ORCID Profile
0000-0002-7961-638X
Current Organisations
Peter MacCallum Cancer Centre
,
Monash Health
,
University of Melbourne
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Publisher: Elsevier BV
Date: 07-2021
Publisher: Springer Science and Business Media LLC
Date: 12-03-2016
DOI: 10.1007/S10620-016-4109-2
Abstract: Barrett's esophagus (BE) is intestinal metaplasia of the lower esophagus and a precursor lesion for esophageal adenocarcinoma (EAC). Both are important health issues as they have rising incidences in the Western world. Improving the management of BE relies on understanding the underlying biology of this disease, but the exact biological mechanisms have been difficult to determine. BE is generally thought to be an acquired condition that develops secondarily to chronic gastroesophageal reflux. However, multiple reports of familial clustering of patients with BE and/or EAC suggest a possible inherited predisposition to BE may be driving this condition, at least in a subset of patients. Identifying the genetic variants that predispose to BE in these families would open up the possibility for blood-based screening tests that could inform decision-making in regard to surveillance strategies, particularly for relatives of patients with BE and/or EAC. Perhaps more importantly, understanding the genetic mechanisms that predispose to BE may provide valuable insights into the biology of this condition and potentially identify novel targets for therapeutic intervention. Here we review the current evidence for a genetic predisposition to BE and discuss the potential implications of these findings.
Publisher: Springer Science and Business Media LLC
Date: 23-05-2022
DOI: 10.1038/S41418-022-01016-W
Abstract: Colorectal cancers (CRCs) often display histological features indicative of aberrant differentiation but the molecular underpinnings of this trait and whether it directly drives disease progression is unclear. Here, we identify co-ordinate epigenetic inactivation of two epithelial-specific transcription factors, EHF and CDX1, as a mechanism driving differentiation loss in CRCs. Re-expression of EHF and CDX1 in poorly-differentiated CRC cells induced extensive chromatin remodelling, transcriptional re-programming, and differentiation along the enterocytic lineage, leading to reduced growth and metastasis. Strikingly, EHF and CDX1 were also able to reprogramme non-colonic epithelial cells to express colonic differentiation markers. By contrast, inactivation of EHF and CDX1 in well-differentiated CRC cells triggered tumour de-differentiation. Mechanistically, we demonstrate that EHF physically interacts with CDX1 via its PNT domain, and that these transcription factors co-operatively drive transcription of the colonic differentiation marker, VIL1 . Compound genetic deletion of Ehf and Cdx1 in the mouse colon disrupted normal colonic differentiation and significantly enhanced colorectal tumour progression. These findings thus reveal a novel mechanism driving epithelial de-differentiation and tumour progression in CRC.
Publisher: American Association for Cancer Research (AACR)
Date: 07-2014
DOI: 10.1158/1541-7786.MCR-14-0158-T
Abstract: Thyroid malignancies are the most common type of endocrine tumors. Of the various histologic subtypes, anaplastic thyroid carcinoma (ATC) represents a subset of all cases but is responsible for a significant proportion of thyroid cancer-related mortality. Indeed, ATC is regarded as one of the more aggressive and hard to treat forms of cancer. To date, there is a paucity of relevant model systems to critically evaluate how the signature genetic abnormalities detected in human ATC contribute to disease pathogenesis. Mutational activation of the BRAF protooncogene is detected in approximately 40% of papillary thyroid carcinoma (PTC) and in 25% of ATC. Moreover, in ATC, mutated BRAF is frequently found in combination with gain-of-function mutations in the p110 catalytic subunit of PI3′-Kinase (PIK3CA) or loss-of-function alterations in either the p53 (TP53) or PTEN tumor suppressors. Using mice with conditional, thyrocyte-specific expression of BRAFV600E, we previously developed a model of PTC. However, as in humans, BRAFV600E-induced mouse PTC is indolent and does not lead to rapid development of end-stage disease. Here, we use mice carrying a conditional allele of PIK3CA to demonstrate that, although mutationally activated PIK3CAH1047R is unable to drive transformation on its own, when combined with BRAFV600E in thyrocytes, this leads to development of lethal ATC in mice. Combined, these data demonstrate that the BRAFV600E cooperates with either PIK3CAH1074R or with silencing of the tumor-suppressor PTEN, to promote development of anaplastic thyroid carcinoma. Implications: This genetically relevant mouse model of ATC will be an invaluable platform for preclinical testing of pathway-targeted therapies for the prevention and treatment of thyroid carcinoma. Mol Cancer Res 12(7) 979–86. ©2014 AACR.
Publisher: Informa UK Limited
Date: 19-09-2013
DOI: 10.4161/CBT.25362
Publisher: Elsevier BV
Date: 08-2015
DOI: 10.1016/J.YDBIO.2015.04.022
Abstract: The phosphoinositide 3-kinase (PI3K)/AKT signalling pathway regulates many cellular functions including proliferation, migration, survival and protein synthesis. Somatic mutations in PIK3CA, the gene encoding the p110α catalytic subunit of PI3K enzyme, are commonly associated with many human cancers as well as recently being implicated in human overgrowth syndromes. However, it is not clear if such mutations can be inherited through the germline. We have used a novel mouse model with Cre recombinase (Cre)-conditional knock-in of the common H1047R mutation into the endogenous Pik3ca gene. Heterozygous expression of the Pik3ca(H1047R) mutation in the developing mouse embryo resulted in failed 'turning' of the embryo and disrupted vascular remodelling within the embryonic and extraembryonic tissues, leading to lethality prior to E10. As vascular endothelial growth factor A (VEGF-A) signalling was disrupted in these embryos, we used Cre under the control of the Tie2 promoter to target the Pik3ca(H1047R) mutation specifically to endothelial cells. In these embryos turning occurred normally but the vascular remodelling defects and embryonic lethality remained, likely as a result of endothelial hyperproliferation. Our results confirm the lethality associated with heterozygous expression of the Pik3ca(H1047R) mutation during development and likely explain the lack of inherited germline PIK3CA mutations in humans.
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/1535-7163.22521228
Abstract: Figure S5 shows MYC directly regulates SLC7A11 levels and APR-246 sensitivity.
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/1535-7163.22521222.V1
Abstract: Supplemental Table 1, 2, 3. Supplemental Materials and Methods.
Publisher: Wiley
Date: 09-2014
DOI: 10.1111/NYAS.12517
Abstract: The following, from the 12th OESO World Conference: Cancers of the Esophagus, includes commentaries on clonal evolution in Barrett's carcinogenesis biomarkers for early detection of esophageal cancer the role of the methylguanine methyl transferase biomarker in the management of adenocarcinoma and the discovery of high-risk genes in families.
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/1535-7163.22521225
Abstract: Gene List from siRNA screen with APR-246 growth inhibition in H1299 p53-null (Sheet 1) and p53-R273H (Sheet 2)
Publisher: American Association for Cancer Research (AACR)
Date: 15-12-2006
DOI: 10.1158/0008-5472.CAN-06-1968
Abstract: Ovarian cancer is the major cause of death from gynecological malignancy, and there is an urgent need for new therapeutic targets. The phosphatidylinositol 3-kinase (PI3K)/AKT pathway has been strongly implicated in the genesis of ovarian cancer. However, to identify and evaluate potential targets for therapeutic intervention, it is critical to understand the mechanism by which the PI3K/AKT pathway facilitates ovarian carcinogenesis. Here, we show that AKT3 is highly expressed in 19 of 92 primary ovarian tumors. Strikingly, purified AKT3 exhibited up to 10-fold higher specific activity than AKT1, potentially lifying the effects of AKT3 overexpression. Consistent with this finding, AKT3 levels in a range of ovarian cancer cell lines correlated with total AKT activity and proliferation rates, implicating AKT3 as a key mediator of ovarian oncogenesis. Specific silencing of AKT3 using short hairpin RNA markedly inhibited proliferation of the two cell lines with highest AKT3 expression and total AKT activity, OVCA429 and DOV13, by slowing G2-M phase transition. These findings are consistent with AKT3 playing a key role in the genesis of at least one subset of ovarian cancers. (Cancer Res 2006 66(24): 11718-25)
Publisher: Informa UK Limited
Date: 2008
DOI: 10.1080/00365520802102489
Abstract: The molecular and cellular events responsible for regulating development of the oesophageal epithelium are not well understood. At least in part, this is due to the lack of a suitable model system with which to study the process. Here, we report development of a manipulable in vivo transplant model for mouse or human oesophageal epithelium. Epithelial cells were isolated from mouse or human oesophagus and inoculated into de-epithelialized and devitalized rat tracheas. The rat trachea, containing cells, was placed subcutaneously under the dorsal skin of immunodeficient mice. We show that a multilayered stratified squamous epithelium can be generated in 4-6 weeks from as few as 5 x 10(4) isolated oesophageal epithelial cells. The reconstituted epithelium recapitulates many of the structural and histological features of the normal oesophageal epithelium, including a basal layer of cuboidal-like cells, suprabasal layers of differentiating squamous cells and, in the case of murine cells, a superficial layer of cornified material. Our model can be used to generate a multilayered normal murine or human epithelium from a single cell suspension of oesophageal epithelial cells. The ability to genetically manipulate the cells prior to growth in the model is a powerful tool with which to study the molecular mechanisms involved in the development of normal oesophagus or in pathogenic processes such as Barrett's metaplasia or tumorigenesis.
Publisher: American Society for Clinical Investigation
Date: 08-11-2013
DOI: 10.1172/JCI69619
Publisher: Wiley
Date: 07-1992
Abstract: Unlike resident peritoneal macrophages (RPM) or tumor necrosis factor alpha (TNF alpha)-primed bone marrow-derived macrophages (BMM), unprimed BMM do not generate superoxide in response to the protein kinase C (PKC) activator, phorbol myristate acetate (PMA). However, these cells do contain significant levels of PKC activity. In contrast to PMA, zymosan induces the generation of superoxide in unprimed BMM, as well as in TNF alpha-primed BMM and RPM. Staurosporine, a potent PKC inhibitor, failed to affect the zymosan-induced production of superoxide by unprimed and TNF alpha-primed BMM and RPM, in spite of substantial inhibition of PMA-induced superoxide production by the primed BMM and RPM. However, when PKC was depleted from unprimed BMM by prolonged (24 h) treatment with phorbol dibutyrate (PdBt) (10(-7) M) the ability of zymosan to induce the production of superoxide was greatly diminished. Such a result could be interpreted as suggesting a role for PKC in the zymosan-induced response, a conclusion which contrasts with the inhibitor data. However, PKC depletion, in this case, is achieved via the PdBt-induced activation of PKC. It is thus possible that it is the initial activation of PKC, rather than its depletion, that suppresses superoxide production. Consistent with this interpretation, the co-stimulation of unprimed BMM with both zymosan and PMA resulted in a reduced superoxide release compared to zymosan alone. The activation of PKC therefore appears to have a suppressive effect on the generation of superoxide by unprimed cells. We thus conclude that PKC is not required for zymosan-induced superoxide production by either primed or unprimed macrophages and suggest that PKC may be involved in regulatory mechanisms restricting superoxide production by macrophages. However, since PMA alone can initiate the release of superoxide from primed BMM and RPM, it would appear that PKC can mediate both stimulatory and suppressive signals for macrophage superoxide production.
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/1535-7163.22521222
Abstract: Supplemental Table 1, 2, 3. Supplemental Materials and Methods.
Publisher: Springer Science and Business Media LLC
Date: 24-11-2017
DOI: 10.1038/S41467-017-02002-4
Abstract: Mutations in PIK3CA are very frequent in cancer and lead to sustained PI3K pathway activation. The impact of acute expression of mutant PIK3CA during early stages of malignancy is unknown. Using a mouse model to activate the Pik3ca H1047R hotspot mutation in the heterozygous state from its endogenous locus, we here report that mutant Pik3ca induces centrosome lification in cultured cells (through a pathway involving AKT, ROCK and CDK2/Cyclin E-nucleophosmin) and in mouse tissues, and increased in vitro cellular tolerance to spontaneous genome doubling. We also present evidence that the majority of PIK3CA H1047R mutations in the TCGA breast cancer cohort precede genome doubling. These previously unappreciated roles of PIK3CA mutation show that PI3K signalling can contribute to the generation of irreversible genomic changes in cancer. While this can limit the impact of PI3K-targeted therapies, these findings also open the opportunity for therapeutic approaches aimed at limiting tumour heterogeneity and evolution.
Publisher: BMJ
Date: 17-07-2015
DOI: 10.1136/GUTJNL-2015-309770
Abstract: p53 is a critical tumour suppressor and is mutated in 70% of oesophageal adenocarcinomas (OACs), resulting in chemoresistance and poor survival. APR-246 is a first-in-class reactivator of mutant p53 and is currently in clinical trials. In this study, we characterised the activity of APR-246 and its effect on p53 signalling in a large panel of cell line xenograft (CLX) and patient-derived xenograft (PDX) models of OAC. In vitro response to APR-246 was assessed using clonogenic survival, cell cycle and apoptosis assays. Ectopic expression, gene knockdown and CRISPR/Cas9-mediated knockout studies of mutant p53 were performed to investigate p53-dependent drug effects. p53 signalling was examined using quantitative RT-PCR and western blot. Synergistic interactions between APR-246 and conventional chemotherapies were evaluated in vitro and in vivo using CLX and PDX models. APR-246 upregulated p53 target genes, inhibited clonogenic survival and induced cell cycle arrest as well as apoptosis in OAC cells harbouring p53 mutations. Sensitivity to APR-246 correlated with cellular levels of mutant p53 protein. Ectopic expression of mutant p53 sensitised p53-null cells to APR-246, while p53 gene knockdown and knockout diminished drug activity. Importantly, APR-246 synergistically enhanced the inhibitory effects of cisplatin and 5-fluorouracil through p53 accumulation. Finally, APR-246 demonstrated potent antitumour activity in CLX and PDX models, and restored chemosensitivity to a cisplatin/5-fluorouracil-resistant xenograft model. APR-246 has significant antitumour activity in OAC. Given that APR-246 is safe at therapeutic levels our study strongly suggests that APR-246 can be translated into improving the clinical outcomes for OAC patients.
Publisher: Springer Science and Business Media LLC
Date: 29-09-2014
DOI: 10.1007/S10620-013-2882-8
Abstract: Esophageal adenocarcinoma (EAC) has a very high case fatality rate and is one of the fastest rising cancers worldwide. At the same time, research into EAC has been h ered by a relative lack of pre-clinical models, including representative cell lines. The purpose of this study was to establish and characterize a new EAC cell line. Tumor cells were isolated from EAC tissue by enzymatic digestion. Origin of the cell line was confirmed by microsatellite based genotyping. A panel of cancer-related genes was screened for mutations by targeted deep sequencing, Sanger sequencing and high resolution melting.CDKN2A promoter methylation was assessed by methylation specific high resolution melting. HER2 lification was assessed by fluorescent in situ hybridization. Immunohistochemistry was used to assess expression of markers in xenografts grown in SCID mice. A novel EAC cell line, OANC1, was derived from a Barrett's-associated EAC. Microsatellite-based genotyping of OANC1 and patient DNA confirmed the origin of the cell line. Sequencing of OANC1 DNA identified homozygous TP53 missense (c.856G[A, p.E286K)and SMAD4 nonsense (c.1333C[T, p.R445X) mutations.OANC1 are tumorigenic when injected sub-cutaneously into SCID mice and xenografts were positive for columnar, glandular and intestinal epithelial markers commonly expressed in EAC. Xenografts exhibited strong p53 expression, consistent with a TP53 mutation. Some proteins, including p16, EGFR and b-catenin, had heterogeneous expression patterns across xenograft cross-sections, indicative of tumor heterogeneity. OANC1 represents a valuable addition to the limited range of pre-clinical models for EAC. This new cell line will be a useful model system for researchers studying both basic and translational aspects of this disease.
Publisher: Wiley
Date: 28-06-2013
DOI: 10.1002/JSO.23357
Abstract: The phosphatidylinositide 3-kinase (PI3K) pathway is an important signalling pathway that is frequently activated in cancer cells. This has led to the emergence of PI3K inhibitors as potential new treatment modalities for many cancers. We have investigated the frequency of molecular changes in the PI3K pathway in gastric cancer. A series of sixty one human gastric cancer specimens and nine human gastric cancer cell lines were screened for PIK3CA mutations and copy number gain by direct sequencing and multiplex ligation-dependent probe lification (MLPA), respectively. PTEN protein levels were assessed by immunohistochemistry. Alterations in the PI3K pathway were found in 33 of 61 (54%) gastric tumours. PIK3CA mutation and copy number gain were detected in 3 (4.9%) and 8 (13.1%), respectively, of 61 gastric cancer s les while PTEN loss was detected in 24 (39%) of the tumours. Two tumours had both PTEN loss and PIK3CA copy number gain. There were no significant associations between these PI3K pathway changes and the clinical features of the tumours. Alterations in the PI3K pathway are frequent in gastric tumours implicating this pathway as a legitimate therapeutic target in gastric cancer.
Publisher: Springer Science and Business Media LLC
Date: 23-11-2011
DOI: 10.1245/S10434-010-1433-1
Abstract: Cancer treatment is now moving toward a personalized approach, promising improved rates of response and survival. A number of studies have employed the use of microarrays to investigate the predictive potential of expression profiling in gastrointestinal (GI) cancer patients. However while many robust predictive classifiers relating to response and prognosis have been generated for GI cancer patients, these have yet to make the transition to the clinic. The main obstacle is the limited cross validation between predictive gene lists identified for the same tumor type and outcome. Differences in the experimental design, analysis, and interpretation of results all contribute to this variation, with numerous factors influencing which genes are highlighted as predictive. While predictive genomics shows immense potential, it is still a relatively new field and the validation of predictive gene lists derived from microarray data remains a challenge. Future studies must carefully consider all aspects of experimental design to ensure a clinically applicable predictive test can be developed. With this in mind, more extensive and collaborative research must be undertaken before microarray-based platforms can be used routinely in tailoring GI cancer treatment and change clinical practice. Larger cohorts and consistency in methodology will enable the findings from this research to make the transition to the clinic.
Publisher: Springer Science and Business Media LLC
Date: 24-02-2007
DOI: 10.1007/S00198-007-0343-Y
Abstract: BMD and clinical risk factors predict hip and other osteoporotic fractures. The combination of clinical risk factors and BMD provide higher specificity and sensitivity than either alone. INTRODUCTION AND HYPOTHESES: To develop a risk assessment tool based on clinical risk factors (CRFs) with and without BMD. Nine population-based studies were studied in which BMD and CRFs were documented at baseline. Poisson regression models were developed for hip fracture and other osteoporotic fractures, with and without hip BMD. Fracture risk was expressed as gradient of risk (GR, risk ratio/SD change in risk score). CRFs alone predicted hip fracture with a GR of 2.1/SD at the age of 50 years and decreased with age. The use of BMD alone provided a higher GR (3.7/SD), and was improved further with the combined use of CRFs and BMD (4.2/SD). For other osteoporotic fractures, the GRs were lower than for hip fracture. The GR with CRFs alone was 1.4/SD at the age of 50 years, similar to that provided by BMD (GR = 1.4/SD) and was not markedly increased by the combination (GR = 1.4/SD). The performance characteristics of clinical risk factors with and without BMD were validated in eleven independent population-based cohorts. The models developed provide the basis for the integrated use of validated clinical risk factors in men and women to aid in fracture risk prediction.
Publisher: Elsevier BV
Date: 03-1979
DOI: 10.1016/0022-1759(79)90081-4
Abstract: A micro-titre assay of neutrophil intracellular bactericidal activity is presented which requires only a relatively small number of cells and which is simple to perform, making it suitable for use in a clinical situation.
Publisher: Elsevier BV
Date: 03-2000
DOI: 10.1016/S0304-3835(99)00372-9
Abstract: Methylation of the p16 gene was studied in 16 oesophageal tumours. Five (31%) of the tumours were found to be methylated in exon 1 and eight (50%) were methylated in exon 2. The loss of p16 protein correlated with methylation of exon 1 (P = 0.005). However, methylation of exon 2, but not exon 1, was found to be associated with late stage tumours (P = 0.01). We conclude that the methylation of exon 2 of p16 may have effects on the progression of oesophageal tumours that are independent of the expression of the p16 protein.
Publisher: Oxford University Press (OUP)
Date: 12-12-2021
DOI: 10.1093/DOTE/DOAA119
Abstract: Clinical services for Barrett’s esophagus have been rising worldwide including Australia, but little is known of the long-term outcomes of such patients. Retrospective studies using data at baseline are prone to both selection and misclassification bias. We investigated the clinical characteristics and outcomes of Barrett’s esophagus patients in a prospective cohort. We recruited patients diagnosed with Barrett’s esophagus in tertiary settings across Australia between 2008 and 2016. We compared baseline and follow-up epidemiological and clinical data between Barrett’s patients with and without dysplasia. We calculated age-adjusted incidence rates and estimated minimally and fully adjusted hazard ratios (HR) to identify those clinical factors related to disease progression. The cohort comprised 268 patients with Barrett’s esophagus (median follow-up 5 years). At recruitment, 224 (84%) had no dysplasia, 44 (16%) had low-grade or indefinite dysplasia (LGD/IND). The age-adjusted incidence of esophageal adenocarcinoma (EAC) was 0.5% per year in LGD/IND compared with 0.1% per year in those with no dysplasia. Risk of progression to high-grade dysplasia/EAC was associated with prior LGD/IND (fully adjusted HR 6.55, 95% confidence interval [CI] 1.96–21.8) but not long-segment disease (HR 1.03, 95%CI 0.29–3.58). These prospective data suggest presence of dysplasia is a stronger predictor of progression to cancer than segment length in patients with Barrett’s esophagus.
Publisher: Wiley
Date: 09-2014
DOI: 10.1111/NYAS.12521
Abstract: The following, from the 12th OESO World Conference: Cancers of the Esophagus, includes commentaries on the relationship between stem cells, cancer, and the esophagus the behavior of esophageal stem cells and the role of genetics and epigenetics in approaches to translational research.
Publisher: Elsevier BV
Date: 08-2001
Publisher: Springer Science and Business Media LLC
Date: 2003
Publisher: Springer Science and Business Media LLC
Date: 05-08-2008
DOI: 10.1007/S12015-008-9031-3
Abstract: The incidence of adenocarcinoma of the esophagus has increased faster than any other internal malignancy over the last 40 years. Despite this, surprisingly little is known about the basic biology of this tissue, particularly with regards to the organization of cell proliferation within the epithelium. This is a matter of crucial importance for our understanding of the pathogenesis of esophageal cancer. Nevertheless, significant advances have recently been made in the identification and functional characterization of both murine and human esophageal stem cells and their progeny in recent years. This places investigators in an exciting position to gain further insights into the processes of tissue renewal and repair on the one hand and the development of dysplasia and malignancy on the other.
Publisher: Elsevier BV
Date: 05-1999
DOI: 10.1016/S1357-2725(99)00008-4
Abstract: The activation of the neutrophil respiratory burst is a two-step process involving an initial 'priming' phase followed by a 'triggering' event. The biochemical mechanisms which underlie these events are yet to be fully elucidated, but the evidence suggests a crucial role for stimulus-induced tyrosine phosphorylation. The enhanced tyrosine phosphorylation observed upon triggering primed cells may reflect an increase in tyrosine kinase activity or a reduction in the levels of the opposing phosphotyrosine phosphatases (PTPases). We have investigated the latter by examining the possibility that lipopolysaccharide (LPS)-induced priming of the neutrophil respiratory burst involves the suppression of cellular PTPase activity. Purified human neutrophils were incubated for 60 min with and without LPS. Priming of the respiratory burst was confirmed by fMet-Leu-Phe-induced cytochrome c reduction. The level of PTPase activity was assessed by dephosphorylation of [32P]RR-src peptide as substrate. Pretreatment of human neutrophils with 200 ng/ml LPS induced a 2.9 +/- 0.3 (mean +/- SEM, n = 3, P = 0.022) fold increase in the fMet-Leu-Phe-triggered respiratory burst. In the same cells, LPS did not induce a significant change in the total cellular PTPase activity (1.02 +/- 0.02-fold, mean +/- SEM, n = 3, P = 0.63). Similarly, stimulation of neutrophils with fMet-Leu-Phe or phorbol myristate acetate did not significantly affect the cellular PTPase activity (P = 0.94 and 0.68, respectively). Our results suggest that suppression of PTPase activity is not the mechanism underlying the priming and/or triggering of the neutrophil respiratory burst.
Publisher: Cold Spring Harbor Laboratory
Date: 24-08-2023
DOI: 10.1101/2023.08.22.553791
Abstract: Caspase-2, one of the most evolutionarily conserved member of the caspase family, is an important regulator of the cellular response to oxidative stress. Given that ferroptosis is suppressed by antioxidant defense pathways, such as that involving selenoenzyme glutathione peroxidase 4 (GPX4), we hypothesised that caspase-2 may play a role in regulating ferroptosis. This study provides the first demonstration of an important and unprecedented function of caspase-2 in protecting cancer cells from undergoing ferroptotic cell death. Specifically, we show that depletion of caspase-2 leads to downregulation of stress response genes including SESN2, HMOX1, SLC7A11 and sensitises mutant-p53 cancer cells to cell death induced by various ferroptosis inducing compounds. Importantly, the canonical catalytic activity of caspase-2 is not required for its role and suggests that caspase-2 regulates ferroptosis via non-proteolytic interaction with other proteins. Using an unbiased BioID proteomics screen, we identified novel caspase-2 interacting proteins (including heat shock proteins and co-chaperones) that regulate cellular responses to stress. Finally, we demonstrate that caspase-2 limits chaperone mediated autophagic degradation of GPX4 to promote survival of mutant-p53 cancer cells. In conclusion, we document a novel role for caspase-2 as a negative regulator of ferroptosis in cells with mutant-p53. Our results provide evidence for a novel function of caspase-2 functions in cell death regulation and open potential new avenues to exploit ferroptosis in cancer therapy.
Publisher: Springer Science and Business Media LLC
Date: 28-03-2017
DOI: 10.1038/NCOMMS14844
Abstract: TP53 , a critical tumour suppressor gene, is mutated in over half of all cancers resulting in mutant-p53 protein accumulation and poor patient survival. Therapeutic strategies to target mutant-p53 cancers are urgently needed. We show that accumulated mutant-p53 protein suppresses the expression of SLC7A11 , a component of the cystine/glutamate antiporter, system x C − , through binding to the master antioxidant transcription factor NRF2. This diminishes glutathione synthesis, rendering mutant-p53 tumours susceptible to oxidative damage. System x C − inhibitors specifically exploit this vulnerability to preferentially kill cancer cells with stabilized mutant-p53 protein. Moreover, we demonstrate that SLC7A11 expression is a novel and robust predictive biomarker for APR-246, a first-in-class mutant-p53 reactivator that also binds and depletes glutathione in tumours, triggering lipid peroxidative cell death. Importantly, system x C − antagonism strongly synergizes with APR-246 to induce apoptosis in mutant-p53 tumours. We propose a new paradigm for targeting cancers that accumulate mutant-p53 protein by inhibiting the SLC7A11–glutathione axis.
Publisher: Elsevier BV
Date: 10-2020
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/2159-8290.22532960.V1
Abstract: Supplementary Figure 7: Characterization of Pik3ca+/HR, Ptenfl/fl and Pik3ca+/HR Ptenfl/fl prostate tumors. Representative images of IHC to detect (A) PCNA and (B) Cleaved-caspase 3 (CC3) in Pik3ca+/HR, Ptenfl/fl and Pik3ca+/HR Ptenfl/fl prostate tissue 2 weeks post-castration compared to uncastrated, age-matched controls (scale bar: 50 um, n = 3). Mice were castrated when prostate carcinoma was prevalent Pik3ca+/HR = 400 d old, Ptenfl/fl = 200 d old and Pik3ca+/HR Ptenfl/fl =100 d old. Quantitative RT-PCR to detect (C) Nkx3.1 and (D) Pbsn mRNA in Wt prostate and Pik3ca+/HR, Ptenfl/fl and Pik3ca+/HR Ptenfl/fl stage-matched prostate carcinomas (n = 5). Error bars: SEM, *P .05 compared to Wt, or as indicated, one-way ANOVA with Tukey's multiple comparison test. (E) Western Blotting of protein lysates isolated from Wt prostate and stage-matched Pik3ca+/HR, Ptenfl/fl and Pik3ca+/HR Ptenfl/fl prostate carcinomas to detect total AKT, p-AKT Thr308 and p-AKT Ser473 (n = 3).
Publisher: Wiley
Date: 10-2013
DOI: 10.1111/NYAS.12252
Abstract: The following paper on the molecular biology of Barrett's esophagus (BE) includes commentaries on signaling pathways central to the development of BE including Hh, NF-κB, and IL-6/STAT3 surgical approaches for esophagectomy and classification of lesions by appropriate therapy the debate over the merits of minimally invasive esophagectomy versus open surgery outcomes for patients with pharyngolaryngoesophagectomy the applications of neoadjuvant chemotherapy and chemoradiotherapy animal models examining the surgical models of BE and esophageal adenocarcinoma the roles of various morphogens and Cdx2 in BE and the use of in vitro BE models for chemoprevention studies.
Publisher: Springer Science and Business Media LLC
Date: 10-05-2022
DOI: 10.1038/S41388-022-02323-9
Abstract: p110α is a catalytic subunit of phosphoinositide 3-kinase (PI3K), a major downstream effector of receptor tyrosine kinase ErbB2, that is lified and overexpressed in 20-30% of breast cancers, 40% of which have an activating mutation in p110α. Despite the high frequency of PIK3CA gain-of-function mutations, their prognostic value is controversial. Here, we employ a knock-in transgenic strategy to restrict the expression of an activated form of ErbB2 and p110α kinase domain mutation (p110α
Publisher: American Association for the Advancement of Science (AAAS)
Date: 30-03-2016
DOI: 10.1126/SCITRANSLMED.AAD9982
Abstract: Mutant Pik3ca gives rise to venous malformations.
Publisher: Oxford University Press (OUP)
Date: 25-05-2017
DOI: 10.1002/BJS.10572
Abstract: The impact of chemotherapy-associated liver injury (CALI) on postoperative outcome in patients undergoing partial hepatectomy for colorectal liver metastases (CRLM) remains controversial. The objective of this study was to clarify the effect of CALI (sinusoidal dilatation (SD), steatosis and steatohepatitis) on postoperative morbidity and mortality by investigating a large data set from multiple international centres. PubMed and Embase were searched for studies published between 1 January 2004 and 31 December 2013 with keywords ‘chemotherapy’, ‘liver resection’, ‘outcome’ and ‘colorectal metastases’ to identify potential collaborating centres. Univariable and multivariable analyses were performed using binary logistic regression models, with results presented as odds ratios (ORs) with 95 per cent confidence intervals. A consolidated database comprising 788 patients who underwent hepatectomy for CRLM in eight centres was obtained. In multivariable analyses, severe SD was associated with increased major morbidity (Dindo–Clavien grade III–V OR 1·73, 95 per cent c.i. 1·02 to 2·95 P = 0·043). Severe steatosis was associated with decreased liver surgery-specific complications (OR 0·52, 95 per cent c.i. 0·27 to 1·00 P = 0·049), whereas steatohepatitis was linked to an increase in these complications (OR 2·08, 1·18 to 3·66 P = 0·012). Subgroup analysis showed that lobular inflammation was the sole component associated with increased overall morbidity (OR 2·22, 1·48 to 3·34 P = 0·001) and liver surgery-specific complications (OR 3·35, 2·11 to 5·32 P & 0·001). Finally, oxaliplatin treatment was linked to severe SD (OR 2·74, 1·67 to 4·49 P & 0·001). An increase in postoperative major morbidity and liver surgery-specific complications was observed after partial hepatectomy in patients with severe SD and steatohepatitis. Postoperative liver failure occurred more often in patients with severe SD.
Publisher: Wiley
Date: 08-1990
Abstract: Several cytokines have previously been shown to prime macrophages for enhanced release of oxygen radicals in response to subsequent stimulation. We now demonstrate that the presence of the macrophage-specific colony stimulating factor-1 (CSF-1) inhibits the priming of murine macrophages by a variety of agents including tumor necrosis factor alpha, granulocyte/macrophage colony stimulating factor, interferon-gamma, and bacterial lipopolysaccharide. CSF-1 is also able to reduce the respiratory burst in the absence of priming. Our results indicate that CSF-1 is a potent negative regulator of the macrophage respiratory burst which acts to oppose the priming (enhancing) action of macrophage activating agents. We propose that CSF-1 may have a potentially important and previously unrecognized, role as a physiological regulator which restricts or terminates the activation of macrophages in order to prevent an uncontrolled inflammatory reaction.
Publisher: Wiley
Date: 28-02-2006
DOI: 10.1002/IJC.21706
Abstract: Mutation of PIK3CA, the gene coding for the p110alpha catalytic subunit of phosphoinositide 3-kinase (PI3K), has been reported in a limited range of human tumors. We now report that PIK3CA is also mutated in esophageal tumors. Single-strand conformational polymorphism (SSCP) and denaturing high-performance liquid chromatography (DHPLC) were used to screen all 20 exons of PIK3CA in 101 s les from 95 in iduals with esophageal cancer and/or Barrett's esophagus. Somatic mutation of PIK3CA was detected in 4 of 35 (11.8%) of esophageal squamous cell carcinomas (SCC) and 3 of 50 (6%) adenocarcinomas. No mutations were detected in any of 17 s les of Barrett's esophagus. For PIK3CB, we screened exons 11 and 22, which code for the regions corresponding to the exon 9 and 20 mutational 'hotspots' of PIK3CA. No somatic changes were detected in PIK3CB This study extends previous observations in other tumor types by demonstrating the presence of somatic PIK3CA mutations in both SCC and adenocarcinoma of the esophagus, thus implicating the PI3K pathway in the initiation and/or progression of esophageal cancers.
Publisher: Springer Science and Business Media LLC
Date: 13-02-2006
Abstract: Multiple lines of evidence have provided compelling evidence for the existence of a tumor suppressor gene (TSG) on chromosome 7q31.1. ST7 may be the target of this genetic instability but its designation as a TSG is controversial. In this study, we show that, functionally, ST7 behaves as a tumor suppressor in human cancer. ST7 suppressed growth of PC-3 prostate cancer cells inoculated subcutaneously into severe combined immunodeficient mice, and increased the latency of tumor detection from 13 days in control tumors to 23 days. Re-expression of ST7 was also associated with suppression of colony formation under anchorage-independent conditions in MDA-MB-231 breast cancer cells and ST7 mRNA expression was downregulated in 44% of primary breast cancers. Expression profiling of PC-3 cells revealed that ST7 predominantly induces changes in genes involved in re-modeling the extracellular matrix such as SPARC, IGFBP5 and several matrix metalloproteinases. These data indicate that ST7 may mediate tumor suppression through modification of the tumor microenvironment.
Publisher: Springer Science and Business Media LLC
Date: 30-06-2014
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/1535-7163.22521240.V1
Abstract: Figure S1 shows TP53 mutation alone is not predictive of cancer cell response to PRIMA-1.
Publisher: Wiley
Date: 15-08-2018
DOI: 10.1111/NYAS.13947
Abstract: Technological progress within the last 15-20 years has significantly increased our knowledge about the molecular basis of cancer development, tumor progression, and treatment response. As a consequence, a vast number of biomarkers have been proposed, but only a small fraction of them have found their way into clinical use. The aim of this paper is to describe the specific demands a clinically relevant biomarker should meet and how biomarkers can be tested stepwise. We name this procedure the "triple-R principle": robustness, reproducibility, and relevance. The usefulness of this principle is illustrated with the marker TP53. Since it is mutated in a broad spectrum of cancer entities, TP53 can be considered a very promising marker. Thus, TP53 has been studied in detail but there is still no explicit consensus about its clinical value. By considering our own experience and reviewing the literature, we demonstrate that a major problem of current biomarker research is disregard of whether the biomarker is prognostic or predictive. As an ex le, it is demonstrated that TP53 is not a prognostic marker, but rather a purely predictive marker, and that disregard of this fact has made this otherwise strong biomarker appear as not being clinically useful so far.
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/2159-8290.22532957.V1
Abstract: Supplemetary Material and Tables S1 - S7
Publisher: Elsevier BV
Date: 11-2011
Publisher: Informa UK Limited
Date: 02-2004
Publisher: Wiley
Date: 14-09-2006
DOI: 10.1002/GCC.20378
Abstract: Although MYB overexpression in colorectal cancer (CRC) is known to be a prognostic indicator for poor survival, the basis for this overexpression is unclear. Among multiple levels of MYB regulation, the most dynamic is the control of transcriptional elongation by sequences within intron 1. The authors have proposed that this regulatory sequence is transcribed into an RNA stem-loop and 19-residue polyuridine tract, and is subject to mutation in CRC. When this region was examined in colorectal and breast carcinoma cell lines and tissues, the authors found frequent mutations only in CRC. It was determined that these mutations allowed increased transcription compared with the wild type sequence. These data suggest that this MYB regulatory region within intron 1 is subject to mutations in CRC but not breast cancer, perhaps consistent with the mutagenic insult that occurs within the colon and not mammary tissue. In CRC, these mutations may contribute to MYB overexpression, highlighting the importance of noncoding sequences in the regulation of key cancer genes.
Publisher: Impact Journals, LLC
Date: 16-11-2016
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/2159-8290.22532963.V1
Abstract: Supplementary Figure 6: Pik3ca+/HR and Ptenfl/fl prostate cancers acquire CRPC, while Pik3ca+/HR Ptenfl/fl mutants are resistant to castration. (A) Representative H& E images of Pik3ca+/HR, Ptenfl/fl and Pik3ca+/HR Ptenfl/fl anterior (AP) and ventral (VP) prostate lobes post-castration (scale bar: 50 um, n = 3). (B) Representative IHC images of Pik3ca+/HR, Ptenfl/fl and Pik3ca+/HR Ptenfl/fl prostate tissue stained to detect Androgen receptor (AR) 2 weeks post-castration compared to uncastrated, age-matched controls (scale bar: 50 um, n = 3). Mice were castrated when prostate carcinoma was prevalent Pik3ca+/HR = 400 d old, Ptenfl/fl = 200 d old and Pik3ca+/HR Ptenfl/fl = 100 d old. Insert displays positive AR nuclei (arrows) in Pik3ca+/HR Ptenfl/fl compound mutants (scale bar: 5 um). (C) Bar chart displaying total prostate weight normalised to body weight for Pik3ca+/HR mice 0, 2 and 42 weeks post-castration (n = 8, 7 and 7, respectively). Error bars: SEM, *P .05 compared to 0 weeks post-castration, or as indicated, one-way ANOVA with Tukey's multiple comparison test. (D) Representative H& E images of Pik3ca+/HR mice 0, 2 and 42 weeks post-castration (scale bar: 100 um). Mice were castrated at 100 d of age.
Publisher: Public Library of Science (PLoS)
Date: 30-05-2012
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/1535-7163.22521237.V1
Abstract: Figure S2 shows APR-246 and PX-12 activity correlate in CTRPv2 and their impact on mutant-p53 thermostability.
Publisher: Elsevier BV
Date: 03-1997
DOI: 10.1016/S0167-4889(96)00149-8
Abstract: Tyrosine phosphorylation is now recognised as a key event in the activation of the macrophage respiratory burst. Since vanadate, a phosphotyrosine phosphatase (PTP) inhibitor is able to enhance the respiratory burst, we proposed that agents which prime the macrophage for enhance respiratory burst activity may do so by suppressing cellular PTP activity. The level of PTP activity in murine bone marrow-derived macrophages (BMM) was assessed by the ability of cell lysates to dephosphorylate 32P-labelled RR-src peptide. In contrast to our hypothesis, pretreatment of BMM with bacterial lipopolysaccharide (LPS), tumor necrosis factor alpha (TNF alpha) or granulocyte/macrophage-colony stimulating factor (GMCSF), agents which prime for enhanced respiratory burst activity, was found to dramatically increase the level of cellular PTP activity. The time-course for this increase correlated well with the time course of priming by these agents. In addition, colony stimulating factor-1, a cytokine which does not prime the macrophage respiratory burst, did not enhance PTP levels. The physiological relevance of the increased PTP activity was further supported by confirming it was active against endogenous tyrosine phosphorylated substrates. Interestingly, phorbol myristate acetate and zymosan, agents which trigger the macrophage respiratory burst, were found to inhibit the PTP activity of BMM. Our results demonstrate the regulation of cellular PTP activity by priming agents and further highlight the importance of tyrosine phosphorylation and dephosphorylation events in the regulation of macrophage function.
Publisher: Oxford University Press (OUP)
Date: 12-10-2007
DOI: 10.1634/STEMCELLS.2006-0421
Abstract: The identification and characterization of esophageal stem cells are critical to our understanding of the biology of the esophageal epithelium in health and disease. However, the proliferative compartment within the mouse esophageal epithelium remains poorly characterized. Here, we report that the basal cells of the mouse esophagus can be separated into three phenotypically and functionally distinct subpopulations based on the expression of α6 integrin and transferrin receptor (CD71). Cells that express high levels of α6 integrin and low levels of CD71, termed α6briCD71dim, are a minor subpopulation of small and undifferentiated cells that are enriched for label-retaining cells and thus represent a putative esophageal stem cell population. Conversely, cells expressing high levels of both α6 integrin and CD71 (α6briCD71bri), the majority of basal esophageal cells, are enriched for actively cycling cells and therefore represent a transit- lifying population. Kinetic analyses revealed that a third cell population, which is α6 integrin-dim and CD71-bright (α6dim), is destined to leave the basal layer and differentiate.
Publisher: Wiley
Date: 30-12-2014
DOI: 10.1096/FJ.14-262782
Abstract: Mutations in PIK3CA, the gene encoding the p110α catalytic subunit of PI3K, are among the most common mutations found in human cancer and have also recently been implicated in a range of overgrowth syndromes in humans. We have used a novel inducible "exon-switch" approach to knock in the constitutively active Pik3ca(H1047R) mutation into the endogenous Pik3ca gene of the mouse. Ubiquitous expression of the Pik3ca(H1047R) mutation throughout the body resulted in a dramatic increase in body weight within 3 weeks of induction (mutant 150 ± 5% wild-type 117 ± 3%, mean ± sem), which was associated with increased organ size rather than adiposity. Severe metabolic effects, including a reduction in blood glucose levels to 59 ± 4% of baseline (11 days postinduction) and undetectable insulin levels, were also observed. Pik3ca(H1047R) mutant mice died earlier (median survival 46.5 d post-mutation induction) than wild-type control mice (100% survival > 250 days). Although deletion of Akt2 increased median survival by 44%, neither organ overgrowth, nor hypoglycemia were rescued, indicating that both the growth and metabolic functions of constitutive PI3K activity can be Akt2 independent. This mouse model demonstrates the critical role of PI3K in the regulation of both organ size and glucose metabolism at the whole animal level.
Publisher: Routledge
Date: 03-2013
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/2159-8290.22532972.V1
Abstract: Supplementary Figure 3: Characterization of Pik3ca-mutated and Pten-deleted prostate hyperplasia and carcinoma. (A) IHC to detect the apoptotic marker Cleaved-Caspase-3 (CC3) in Wt, Pik3ca+/HR and Ptenfl/fl mice at 400 d (scale bar: 50 um). (B) Quantitation of CC3-positive nuclei in Wt, Pik3ca+/HR and Ptenfl/fl prostate epithelium (n = 3, *P .05 compared to Wt, or as indicated, one-way ANOVA with Tukey's multiple comparison test, ns = not significant. Error bars: SEM). (C) IHC to detect CK5 and CK8 in Pik3ca+/HR and Ptenfl/fl carcinomas (representative images from 3 prostates per genotype, scale bar: 50 um). (D) Representative IHC images to detect PTEN, mTORC1 signaling components (p-AKT Thr308, p-RPS6 Ser235/236 and p-4E-BP1 Thr37/46) and mTORC2 substrates (p-AKT Ser473 and p-NDRG1 Thr346) in Pik3ca+/HR and Ptenfl/fl hyperplastic lesions (n = 3, scale bar: 50 um). IHC quantitation for (E) p-AKT Thr308, (F) p-RPS6 Ser235/236, (G) p-4E-BP1 Thr37/46, (H) p-AKT Ser473 and (I) p-NDRG1 Thr346 in Pik3ca+/HR and Ptenfl/fl prostate hyperplastic lesions (n = 3, Error bars: SEM, *P 0.05, unpaired, two-tailed t-test).
Publisher: Oxford University Press (OUP)
Date: 1995
Publisher: Springer Science and Business Media LLC
Date: 18-10-2021
DOI: 10.1038/S41419-021-04141-5
Abstract: Anal cancer is a rare disease that has doubled in incidence over the last four decades. Current treatment and survival of patients with this disease has not changed substantially over this period of time, due, in part, to a paucity of preclinical models to assess new therapeutic options. To address this hiatus, we set-out to establish, validate and characterise a panel of human anal squamous cell carcinoma (ASCC) cell lines by employing an explant technique using fresh human ASCC tumour tissue. The panel of five human ASCC cell lines were validated to confirm their origin, squamous features and tumourigenicity, followed by molecular and genomic (whole-exome sequencing) characterisation. This panel recapitulates the genetic and molecular characteristics previously described in ASCC including phosphoinositide-3-kinase (PI3K) mutations in three of the human papillomavirus (HPV) positive lines and TP53 mutations in the HPV negative line. The cell lines demonstrate the ability to form tumouroids and retain their tumourigenic potential upon xenotransplantation, with varied inducible expression of major histocompatibility complex class I (MHC class I) and Programmed cell death ligand 1 (PD-L1). We observed differential responses to standard chemotherapy, radiotherapy and a PI3K specific molecular targeted agent in vitro, which correlated with the clinical response of the patient tumours from which they were derived. We anticipate this novel panel of human ASCC cell lines will form a valuable resource for future studies into the biology and therapeutics of this rare disease.
Publisher: Elsevier BV
Date: 06-1994
DOI: 10.1016/0167-4889(94)90175-9
Abstract: We have investigated the relationship between tyrosine phosphorylation and respiratory-burst activity in murine bone-marrow-derived macrophages (BMM) stimulated with phorbol myristate acetate (PMA). In unprimed BMM, a good correlation was observed between the net level of tyrosine phosphorylation and the activity of the respiratory burst. The phosphotyrosine phosphatase inhibitor, vanadate, enhanced both tyrosine phosphorylation and respiratory-burst activity triggered by PMA. Furthermore, the tyrosine kinase inhibitor, ST638, abolished both tyrosine phosphorylation and respiratory-burst activity stimulated by PMA. However, in BMM primed by preexposure to TNF alpha, the correlation between net tyrosine phosphorylation and respiratory-burst activity triggered by PMA was not maintained. ST638 was found to only partially inhibit the PMA-triggered respiratory burst under conditions where PMA-stimulated tyrosine phosphorylation was abolished. We conclude that PMA can activate the macrophage respiratory burst by both tyrosine-kinase-dependent and -independent pathways.
Publisher: American Physiological Society
Date: 15-12-2012
Abstract: The molecular mechanism underlying the development of Barrett's esophagus (BE), the precursor to esophageal adenocarcinoma, remains unknown. Our previous work implicated sonic hedgehog (Shh) signaling as a possible driver of BE and suggested that bone morphogenetic protein 4 (Bmp4) and Sox9 were downstream mediators. We have utilized a novel in vivo tissue reconstitution model to investigate the relative roles of Bmp4 and Sox9 in driving metaplasia. Epithelia reconstituted from squamous epithelial cells or empty vector-transduced cells had a stratified squamous phenotype, reminiscent of normal esophagus. Expression of Bmp4 in the stromal compartment activated signaling in the epithelium but did not alter the squamous phenotype. In contrast, expression of Sox9 in squamous epithelial cells induced formation of columnar-like epithelium with expression of the columnar differentiation marker cytokeratin 8 and the intestinal-specific glycoprotein A33. In patient tissue, A33 protein was expressed specifically in BE, but not in normal esophagus. Expression of Cdx2, another putative driver of BE, alone had no effect on reconstitution of a squamous epithelium. Furthermore, epithelium coexpressing Cdx2 and Sox9 had a phenotype similar to epithelium expressing Sox9 alone. Our results demonstrate that Sox9 is sufficient to drive columnar differentiation of squamous epithelium and expression of an intestinal differentiation marker, reminiscent of BE. These data suggest that Shh-mediated expression of Sox9 may be an important early event in the development of BE and that the potential for inhibitors of the hedgehog pathway to be used in the treatment of BE and/or esophageal adenocarcinoma could be tested in the near future.
Publisher: Elsevier BV
Date: 11-2001
Publisher: Informa UK Limited
Date: 1994
DOI: 10.3109/08977199409000236
Abstract: The activity of phosphatidylinositol (PI) 3-kinase was examined in murine bone marrow-derived macrophages (BMM) stimulated with the haematopoietic growth factors colony stimulating factor-1 (CSF-1) and granulocyte/macrophage-CSF (GM-CSF). PI 3-kinase was immunoprecipitated from cell lysates using anti-phosphotyrosine antibody or an antibody directed against the 85K subunit of PI 3-kinase, and the activity assayed by the phosphorylation of PI in the presence of [gamma 32P]-ATP. The results demonstrate that CSF-1 increases the activity of PI 3-kinase, as compared to the non-stimulated control, in murine macrophages. Maximum activity was seen after 10 min of stimulation with CSF-1 at 3000-5000 U/ml. The dose-response of CSF-1 is consistent with other biochemical effects of CSF-1 seen in the BMM. GM-CSF also stimulated PI 3-kinase activity although to a lesser extent than CSF-1, correlating well with their degree of mitogenic activity on the BMM. Non-mitogenic macrophage activating agents, such as the phorbol myristate acetate, lipopolysaccharide, concanavalin A and formyl-methionyl-leucyl-phenylalanine, did not significantly increase the PI 3-kinase activity. Furthermore, CSF-1 failed to stimulate PI 3-kinase activity in resident peritoneal macrophages, a population of macrophages with poor proliferative capacity. These results suggest that the PI 3-kinase activity may be involved in the haemopoietic growth factor signalling pathways regulating macrophage growth.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 02-2018
DOI: 10.1097/DCR.0000000000001010
Abstract: Anal squamous cell carcinoma is a rare cancer with a high cure rate, making research into the treatment of locoregional failure difficult. The purpose of this study was to examine factors related to local treatment failure and determine the outcomes of patients undergoing local salvage resection. This was a retrospective cohort study. This study was conducted at a quaternary referral center. Patients with anal squamous cell carcinoma treated with chemoradiotherapy between January 1983 and December 2015 were included. The influence of patient-, tumor-, and treatment-related factors on the primary outcome measures of locoregional failure, overall survival, and disease-free survival were investigated. Of 467 patients with anal squamous cell carcinoma, 63 experienced locoregional failure with 41 undergoing salvage resection. Twenty-seven patients (38%) had persistent disease and 36 (62%) developed locoregional recurrence. Multivariate analysis identified tumor stage (HR, 3.16 p 0.002) as an independent predictor of locoregional failure. Thirty abdominoperineal resections and 11 pelvic exenterations were undertaken with no surgical mortality. At a median follow-up of 20 months (range, 4–150 months), 5-year overall and disease-free survival for the salvage cohort was 51% and 47%. Margin positivity was an independent predictor for relapse post-salvage surgery on multivariate analysis (HR, 20.1 p = 0.027). Nineteen patients (48%) developed further relapse, which included all 10 patients with a positive resection margin, 3 of whom underwent re-resection. Of the 19 patients with relapse, 3 remain alive and 2 have persistent disease. Limitations include the retrospective nature of the database, the prolonged time period of the study, and episodes of incomplete data. Advanced T stage is an independent predictor of local failure in anal squamous cell carcinoma. Most patients can be salvaged, with a positive resection margin being a strong predictor of further relapse and poor outcome. See Video Abstract at links.lww.com/DCR/A515.
Publisher: American Society of Clinical Oncology (ASCO)
Date: 11-2018
DOI: 10.1200/PO.18.00075
Abstract: The presence of tumor-infiltrating lymphocytes (TILs) in tumors is superior to conventional pathologic staging in predicting patient outcome. However, their presence does not define TIL functionality. Here we developed an assay that tests TIL cytotoxicity in patients with locally advanced rectal cancer before definitive treatment, identifying those who will obtain a pathologic complete response (pCR). We also used the assay to demonstrate the rescue of TIL function after checkpoint inhibition blockade (CIB). Thirty-four consecutive patients were identified initially, with successful completion of the assay before surgery in those 17 patients who underwent full treatment. An in vitro cytotoxic assay of rectal cancer tumoroids cocultured with patient-matched TILs was established and validated. Newly diagnosed patients were recruited with pretreatment biopsy specimens processed within 1 month. Evaluation of TIL-mediated tumoroid lysis was performed by measuring the mean fluorescence intensity of cell death marker, propidium iodide. CIB (anti–programmed cell death protein 1 [anti–PD-1] antibody) response was also assessed in a subset of patient specimens. Six of the 17 patients achieved an objective pCR on final evaluation of the resected specimen after neoadjuvant chemoradiotherapy. Cytotoxic killing identified the pCR group with a higher mean fluorescence intensity (27,982 [95% CI, 25,340 to 30,625]) compared with the non-pCR cohort (12,428 [95% CI, 9,434 to 15,423] p .001). Assessment of the effectiveness of CIB revealed partial restoration of cytotoxicity in TILs with increased PD-1 expression with anti–PD-1 antibody exposure. Evaluating TIL function can be undertaken within weeks of the diagnostic biopsy, affording the potential to alter patient management decisions and refine selection for a watch-and-wait protocol. This cytotoxic assay also has the potential to serve as a platform to assist in the additional development of CIB.
Publisher: Portland Press Ltd.
Date: 14-02-2014
DOI: 10.1042/BJ20131412
Abstract: PIK3CA, the gene encoding the p110α catalytic subunit of PI3K (phosphoinositide 3-kinase), is mutated in approximately 20% of sporadic CRCs (colorectal cancers), but the role of these mutations in the pathogenesis of CRC remains unclear. In the present study we used a novel mouse model to investigate the role of the Pik3caH1047R mutation, the most common PIK3CA mutation in CRC, during the development and progression of intestinal cancer. Our results demonstrate that Pik3caH1047R, when expressed at physiological levels, is insufficient to initiate intestinal tumorigenesis however, in the context of Apc (adenomatous polyposis coli) loss, which is observed in 80% of CRCs and by itself results in benign intestinal adenomas, the Pik3caH1047R mutation promotes the development of highly aggressive and invasive adenocarcinomas in both the small and large intestines. The results of the present study show that an activating Pik3ca mutation can act in tandem with Apc loss to drive the progression of gastrointestinal cancer and thus this disease may be susceptible to therapeutic targeting using PI3K pathway inhibitors.
Publisher: Wiley
Date: 09-2001
DOI: 10.1046/J.1440-1746.2001.02588.X
Abstract: The cellular configuration of the human colon suggests a predetermined organization that creates specific microenvironments. The role of pericryptal fibroblasts in this microenvironment has been the subject of considerable speculation. This study examined the expression of growth factors and their receptors by colonic crypt epithelium and pericryptal fibroblasts. Pericryptal fibroblast cells were isolated and cultured from decrypted human colonic mucosa. The pericryptal fibroblast cells expressed messenger RNA (mRNA) for interleukin-6 (IL-6), leukemia inhibitory factor (LIF), LIF receptor alpha, and the common coreceptor glycoprotein 130 (GP130), but not the IL-6 receptor alpha. Interleukin-6 protein expression was confirmed by the analysis of conditioned medium and immunohistochemistry. In comparison, normal colonic epithelial cells express mRNA for LIF but not IL-6 as well as the receptors for GP-130, IL-6 receptor alpha but not LIF receptor alpha. As cultures of normal human colonic epithelial cells were not available, the conditioned medium was assayed from established colon carcinoma cell lines and demonstrated a secretion of LIF but not IL-6 protein. The expression of reciprocal cytokine and receptor expression suggest that there is a paracrine relationship between pericryptal fibroblasts and colonic epithelium.
Publisher: American Association for Cancer Research (AACR)
Date: 11-2004
DOI: 10.1158/0008-5472.CAN-04-2933
Abstract: Phosphatidylinositol 3′-kinases are lipid kinases with important roles in neoplasia. Recently, a very high frequency of somatic mutations in PIK3CA has been reported among a large series of colorectal cancers. However, the relevance of PIK3CA mutation in other cancer types remains unclear because of the limited number of tumors investigated. We have screened a total of 284 primary human tumors for mutations in all coding exons of PIK3CA using a combination of single stranded conformational polymorphism and denaturing high-performance liquid chromatography analysis. Among 70 primary breast cancers, 40% (28 of 70) harbored mutations in PIK3CA, making it the most common mutation described to date in this cancer type. Mutations were not associated with histologic subtype, estrogen receptor status, grade or presence of tumor in lymph nodes. Among the primary epithelial ovarian cancers only 11 of 167 (6.6%) contain somatic mutations, but there was a clear histologic subtype bias in their distribution. Only 2 of 88 (2.3%) of serous carcinomas had PIK3CA mutations compared with 8 of 40 (20.0%) endometrioid and clear cell cancers, which was highly significant (P = 0.001). In contrast, PIK3CA gene lification (& -fold) was common among all histologic subtypes (24.5%) and was inversely associated with the presence of mutations. Overall, PIK3CA mutation or gene lification was detected in 30.5% of all ovarian cancers and 45% of the endometrioid and clear cell subtypes. Our study is the first direct evidence that PIK3CA is an oncogene in ovarian cancer and greatly extends recent findings in breast cancer.
Publisher: Informa UK Limited
Date: 04-2013
DOI: 10.4161/ONCI.24185
Publisher: American Association for Cancer Research (AACR)
Date: 09-2004
DOI: 10.1158/0008-5472.CAN-04-1207
Abstract: Sprouty (Spry) proteins were found to be endogenous inhibitors of the Ras/mitogen-activated protein kinase pathway that play an important role in the remodeling of branching tissues. We investigated Spry expression levels in various cancers and found that Spry1 and Spry2 were down-regulated consistently in breast cancers. Such prevalent patterns of down-regulation may herald the later application of these isoforms as tumor markers that are breast cancer specific and more profound than currently characterized markers. Spry1 and 2 were expressed specifically in the luminal epithelial cells of breast ducts, with higher expression during stages of tissue remodeling when the epithelial ducts are forming and branching. These findings suggest that Sprys might be involved as a modeling counterbalance and surveillance against inappropriate epithelial expansion. The abrogation of endogenous Spry activity in MCF-7 cells by the overexpression of a previously characterized dominant-negative mutant of Spry, hSpry2Y55F resulted in enhanced cell proliferation in vitro. The hSpry2Y55F stably expressing cells also formed larger and greater number of colonies in the soft-agar assay. An in vivo nude mice assay showed a dramatic increase in the tumorigenic potential of hSpry2Y55F stable cells. The consistent down-regulation of Spry1 and 2 in breast cancer and the experimental evidence using a dominant-negative hSpry2Y55F indicate that Spry proteins may actively maintain tissue integrity that runs amok when their expression is decreased below normal threshold levels. This alludes to a previously unrecognized role for Sprys in cancer development.
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/2159-8290.22532966.V1
Abstract: Supplementary Figure 5: Pik3caH1047R mutation and Pten-deletion synergize to promote prostate cancer by increasing mTORC1/2 signaling. Histograms displaying phenotype incidence for anterior (A) and ventral (B) prostate lobes at 56 and 100 days of age. (C) Representative IHC images of Pik3ca+/HR Ptenfl/fl prostate tumors at 100 d stained to detect CK8, CK5 and SMA (n = 3, scale bar: 50 um). (D) Bar chart displaying total prostate weight normalised to body weight for Wt (n = 7), Pik3ca+/HR (n = 8), Ptenfl/fl (n = 8) and Pik3ca+/HR Ptenfl/fl (n = 7) 100 d old mice. Error bars: SEM, *P .05 compared to Wt or as indicated, one-way ANOVA with Tukey's multiple comparison test. (E) Quantitation of the apoptotic marker Cleaved-Caspase-3 (CC3) positive nuclei and (F) representative IHC images of CC3 staining in Pik3ca+/HR, Ptenfl/fl and Pik3ca+/HR Ptenfl/fl stage-matched invasive prostate carcinoma (scale bar: 50 um, n = 3, one-way ANOVA with Tukey's multiple comparison test. Error bars: SEM). (G) Representative IHC images of Pik3ca+/HR, Ptenfl/fl and Pik3ca+/HR Ptenfl/fl stage-matched invasive prostate carcinoma stained to detect p-AKT Thr308, p-RPS6 Ser235/236, p-4E-BP1 Thr37/46, p-AKT Ser473 and p-NDRG1 Thr346 (scale bar: 50 um). (H) Representative images of RNA in situ hybridisation (ISH) to detect positive (housekeeping gene PPIB, peptidylprolyl isomerase B) and negative (bacterial gene dapB) control probes to confirm RNA quality and the absence of background signal respectively (scale bar: 50 um, insert scale bar: 5 um).
Publisher: Wiley
Date: 18-01-2007
DOI: 10.1002/IJC.22501
Abstract: Esophageal cancer is a particularly aggressive tumor with poor prognosis, however, our current knowledge of the genes and pathways involved in tumorigenesis of the esophagus are limited. To obtain insight into the molecular processes underlying tumorigenesis of the esophagus, we have used cDNA microarrays to compare the gene expression profiles of 128 tissue s les representing the major histological subtypes of esophageal cancer (squamous cell carcinoma and adenocarcinoma (ADC)) as well as Barrett's esophagus (BE), the precursor lesion to ADC, and normal esophageal epithelium. Linear discriminant analysis and unsupervised hierarchical clustering show the separation of s les into 4 distinct groups consistent with their histological subtype. Differentially expressed genes were identified between each of the tissue types. Comparison of gene ontologies and gene expression profiles identified gene profiles specific to esophageal cancer, as well as BE. "Esophageal cancer clusters," representing proliferation, immune response, and extracellular matrix genes were identified, as well as digestion, hydrolase, and transcription factor clusters specific to the columnar phenotype observed during BE and esophageal ADC. These clusters provide valuable insight into the molecular and functional differences between normal esophageal epithelium, BE, and the 2 histologically distinct forms of esophageal cancers. Our thorough, unbiased analysis provides a rich source of data for further studies into the molecular basis of tumorigenesis of the esophagus, as well as identification of potential biomarkers for early detection of progression.
Publisher: Proceedings of the National Academy of Sciences
Date: 17-05-2010
Abstract: PIK3CA mutations are reported to be present in approximately 25% of breast cancer (BC), particularly the estrogen receptor–positive (ER+) and HER2-overexpressing (HER2+) subtypes, making them one of the most common genetic aberrations in BC. In experimental models, these mutations have been shown to activate AKT and induce oncogenic transformation, and hence these lesions have been hypothesized to render tumors highly sensitive to therapeutic PI3K/mTOR inhibition. By analyzing gene expression and protein data from nearly 1,800 human BCs, we report that a PIK3CA mutation–associated gene signature ( PIK3CA -GS) derived from exon 20 (kinase domain) mutations was able to predict PIK3CA mutation status in two independent datasets, strongly suggesting a characteristic set of gene expression–induced changes. However, in ER+/HER2− BC despite pathway activation, PIK3CA mutations were associated with a phenotype of relatively low mTORC1 signaling and a good prognosis with tamoxifen monotherapy. The relationship between clinical outcome and the PIK3CA -GS was also assessed. Although the PIK3CA -GS was not associated with prognosis in ER− and HER2+ BC, it could identify better clinical outcomes in ER+/HER2− disease. In ER+ BC cell lines, PIK3CA mutations were also associated with sensitivity to tamoxifen. These findings could have important implications for the treatment of PIK3CA -mutant BCs and the development of PI3K/mTOR inhibitors.
Publisher: Springer Science and Business Media LLC
Date: 07-06-2021
DOI: 10.1038/S41467-021-23641-8
Abstract: Barrett’s esophagus in gastrointestinal reflux patients constitutes a columnar epithelium with distal characteristics, prone to progress to esophageal adenocarcinoma. HOX genes are known mediators of position-dependent morphology. Here we show HOX collinearity in the adult gut while Barrett’s esophagus shows high HOXA13 expression in stem cells and their progeny. HOXA13 overexpression appears sufficient to explain both the phenotype (through downregulation of the epidermal differentiation complex) and the oncogenic potential of Barrett’s esophagus. Intriguingly, employing a mouse model that contains a reporter coupled to the HOXA13 promotor we identify single HOXA13-positive cells distally from the physiological esophagus, which is mirrored in human physiology, but increased in Barrett’s esophagus. Additionally, we observe that HOXA13 expression confers a competitive advantage to cells. We thus propose that Barrett’s esophagus and associated esophageal adenocarcinoma is the consequence of expansion of this gastro-esophageal HOXA13 -expressing compartment following epithelial injury.
Publisher: Wiley
Date: 08-05-2018
DOI: 10.1111/CODI.14106
Abstract: The current standard of care for locally advanced rectal cancer involves neoadjuvant chemoradiotherapy (CRT) followed by total mesorectal excision. There is a spectrum of response to neoadjuvant therapy however, the prognostic value of tumour regression grade (TRG) in predicting disease-free survival (DFS) or overall survival (OS) is inconsistent in the literature. This study was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A systematic search was undertaken using Ovid MEDLINE, Embase and Google Scholar. Inclusion criteria were Stage II and III locally advanced rectal cancer treated with long-course CRT followed by radical surgery. The aim of the meta-analysis was to assess the prognostic implication of each TRG for rectal cancer following neoadjuvant CRT. Long-term prognosis was assessed. The main outcome measures were DFS and OS. A random effects model was performed to pool the hazard ratio (HR) from all included studies. There were 4875 patients from 17 studies, with 775 (15.9%) attaining a pathological complete response (pCR) and 719 (29.9%) with no response. A significant association with OS was identified from a pooled-estimated HR for pCR (HR = 0.47, P = 0.002) and nonresponding tumours (HR = 2.97 P < 0.001). Previously known tumour characteristics, such as ypN, lymphovascular invasion and perineural invasion, were also significantly associated with DFS and OS, with estimated pooled HRs of 2.2, 1.4 and 2.3, respectively. In conclusion, the degree of TRG was of prognostic value in predicting long-term outcomes. The current challenge is the development of a high-validity tests to predict pCR.
Publisher: Elsevier BV
Date: 12-2013
DOI: 10.1016/J.EJCA.2013.08.007
Abstract: Ovarian cancer is the major cause of death from gynaecological malignancy with a 5year survival of only ∼30% due to resistance to platinum and paclitaxel-based first line therapy. Dysregulation of the phosphoinositide 3-kinase/mammalian target of rapamycin (PI3K/mTOR) and RAS/extracellular signal-regulated kinase (ERK) pathways is common in ovarian cancer, providing potential new targets for 2nd line therapy. We determined the inhibition of proliferation of an extensive panel of ovarian cancer cell lines, encompassing all the major histotypes, by the dual PI3K/mTOR inhibitor PF-04691502 and a MEK inhibitor, PD-0325901. In addition, we analysed global gene expression, mutation status of key PI3K/mTOR and RAS/ERK pathway members and pathway activation to identify predictors of drug response. PF-04691502 inhibits proliferation of the majority of cell lines with potencies that correlate with the extent of pathway inhibition. Resistant cell lines were characterised by activation of the RAS/ERK pathway as indicated by differential gene expression profiles and pathway activity analysis. PD-0325901 suppressed growth of a subset of cell lines that were characterised by high basal RAS/ERK signalling. Strikingly, using PF-04691502 and PD-0325901 in combination resulted in synergistic growth inhibition in 5/6 of PF-04691502 resistant cell lines and two cell lines resistant to both single agents showed robust synergistic growth arrest. Xenograft studies confirm the utility of combination therapy to synergistically inhibit tumour growth of PF-04691502-resistant tumours in vivo. These studies identify dual targeted inhibitors of PI3K/mTOR in combination with inhibitors of RAS/ERK signalling as a potentially effective new approach to treating ovarian cancer.
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/2159-8290.22532969.V1
Abstract: Supplementary Figure 4: Pik3caH1047R heterozygous oncogenic mutation causes p110alpha-dependent prostate cancer. Representative H& E images (scale bar: 100 um) for Pik3ca+/HR and Ptenfl/fl dorsolateral prostate and histograms displaying phenotype incidence for anterior (B) and ventral (C) prostate lobes from Pik3ca+/HR and Ptenfl/fl mice treated with vehicle, p110alpha�inhibitor (A66), p110beta inhibitor (TGX-221), pan-PI3K inhibitor (BKM120) or A66 + TGX-221 for 4 weeks. ND = not done. A66 and TGX-221 were generated in house by P.R.S. (University of Auckland, New Zealand) (14) and BKM120 was obtained from SYNkinase (Australia).
Publisher: MDPI AG
Date: 23-04-2019
DOI: 10.3390/BIOM9040158
Abstract: The phosphatidylinositol 3-kinase (PI3K) pathway is involved in a myriad of cellular signalling pathways that regulate cell growth, metabolism, proliferation and survival. As a result, alterations in the PI3K pathway are frequently associated with human cancers. Indeed, PIK3CA—the gene encoding the p110α catalytic subunit of PI3K—is one of the most commonly mutated human oncogenes. PIK3CA mutations have also been implicated in non-malignant conditions including congenital overgrowth syndromes and vascular malformations. In order to study the role of PIK3CA mutations in driving tumorigenesis and tissue overgrowth and to test potential therapeutic interventions for these conditions, model systems are essential. In this review we discuss the various mouse models currently available for preclinical studies into the biological consequences and clinical significance of PIK3CA mutations.
Publisher: Wiley
Date: 08-1984
DOI: 10.1111/J.1751-0813.1984.TB15538.X
Abstract: The synthesis and reactivity of a dinickel bridging carbene is described. The previously reported [
Publisher: Oxford University Press (OUP)
Date: 30-04-2018
Publisher: Springer Science and Business Media LLC
Date: 09-07-2018
DOI: 10.1245/S10434-018-6626-Z
Abstract: Clinical trials report improved overall survival following neoadjuvant chemoradiotherapy in patients undergoing surgery for esophageal adenocarcinoma, with a 10-15% survival improvement. MicroRNAs (miRNAs) are small noncoding RNAs that are known to direct the behavior of cancers, including response to treatment. We investigated the ability of miRNAs to predict outcomes after neoadjuvant chemoradiotherapy. Endoscopic biopsies from esophageal adenocarcinomas were obtained before neoadjuvant chemoradiotherapy and esophagectomy. miRNA levels were measured in the biopsies using next generation sequencing and compared with pathological response in the surgical resection, and subsequent survival. miRNA ratios that predicted pathological response were identified by Lasso regression and leave-one-out cross-validation. Association between miRNA ratio candidates and relapse-free survival was assessed using Kaplan-Meier analysis. Cox regression and Harrell's C analyses were performed to assess the predictive performance of the miRNAs. Two miRNA ratios (miR-4521/miR-340-5p and miR-101-3p/miR-451a) that predicted the pathological response to neoadjuvant chemoradiotherapy were found to be associated with relapse-free survival. Pretreatment expression of these two miRNA ratios, pretreatment tumor differentiation, posttreatment AJCC histopathological tumor regression grading, and posttreatment tumor clearance/margins were significant factors associated with survival in Cox regression analysis. Multivariate analysis of the two ratios together with pretherapy factors resulted in a risk prediction accuracy of 85% (Harrell's C), which was comparable with the prediction accuracy of the AJCC treatment response grading (77%). miRNA-ratio biomarkers identified using next generation sequencing can be used to predict disease free survival following neoadjuvant chemoradiotherapy and esophagectomy in patients with esophageal adenocarcinoma.
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/2159-8290.22532975.V1
Abstract: Supplementary Figure 2: Heterozygous Pik3caH1047R oncogenic mutation causes invasive prostate cancer in mice that is phenotypically distinct to Pten-null prostate cancer. (A) Sequencing cDNA isolated from PBiCre+/- Pik3ca+/HR prostate tissue confirmed heterozygosity at known silent base changes within mutant exon 20 adjacent to exon 19, indicating recombination has occurred. (B) allele-specific PCR of cDNA isolated from PBiCre+/- prostate tissue expressing either Pik3ca+/+ (Wt) or Pik3ca+/HR alleles (as previously described (13)) revealed the presence of the mutant exon 20 in PBiCre+/- Pik3ca+/HR prostate cDNA, but not in PBiCre+/- Wt prostate cDNA. (C) Representative H& E images of PBiCre+/- Wt, Pik3ca+/HR and Ptenfl/fl ventral and anterior prostate epithelium at 400 d (scale bar: 100 um). Phenotype incidence plots for PBiCre+/- Wt, Pik3ca+/HR and Ptenfl/fl ventral (D) and anterior (E) prostate lobes. VP = Ventral prostate, AP = anterior prostate, PIN = prostate intraepithelial neoplasia. (F) IHC to detect SMA in Wt, Pik3ca+/HR and Ptenfl/fl mice at 400 d (scale bar: 50 um). (G) Quantitation of PCNA-positive nuclei in PBiCre+/- Pik3ca+/HR and Ptenfl/fl prostate hyperplastic lesions. *P .001, one-way ANOVA with Tukey's multiple comparison test, n = 3. Error bars: SEM.
Publisher: American Association for Cancer Research (AACR)
Date: 26-07-2021
DOI: 10.1158/1535-7163.MCT-21-0067
Abstract: APR-246 (eprenetapopt) is in clinical development with a focus on hematologic malignancies and is promoted as a mutant-p53 reactivation therapy. Currently, the detection of at least one TP53 mutation is an inclusion criterion for patient selection into most APR-246 clinical trials. Preliminary results from our phase Ib/II clinical trial investigating APR-246 combined with doublet chemotherapy [cisplatin and 5-fluorouracil (5-FU)] in metastatic esophageal cancer, together with previous preclinical studies, indicate that TP53 mutation status alone may not be a sufficient biomarker for APR-246 response. This study aims to identify a robust biomarker for response to APR-246. Correlation analysis of the PRIMA-1 activity (lead compound to APR-246) with mutational status, gene expression, protein expression, and metabolite abundance across over 700 cancer cell lines (CCL) was performed. Functional validation and a boutique siRNA screen of over 850 redox-related genes were also conducted. TP53 mutation status was not consistently predictive of response to APR-246. The expression of SLC7A11, the cystine/glutamate transporter, was identified as a superior determinant of response to APR-246. Genetic regulators of SLC7A11, including ATF4, MDM2, wild-type p53, and c-Myc, were confirmed to also regulate cancer-cell sensitivity to APR-246. In conclusion, SLC7A11 expression is a broadly applicable determinant of sensitivity to APR-246 across cancer and should be utilized as the key predictive biomarker to stratify patients for future clinical investigation of APR-246.
Publisher: T.M.C. Asser Press
Date: 24-12-2013
Publisher: American Association for Cancer Research (AACR)
Date: 31-05-2018
DOI: 10.1158/2159-8290.CD-17-0867
Abstract: Genetic alterations that potentiate PI3K signaling are frequent in prostate cancer, yet how different genetic drivers of the PI3K cascade contribute to prostate cancer is unclear. Here, we report PIK3CA mutation/ lification correlates with poor survival of patients with prostate cancer. To interrogate the requirement of different PI3K genetic drivers in prostate cancer, we employed a genetic approach to mutate Pik3ca in mouse prostate epithelium. We show Pik3caH1047R mutation causes p110α-dependent invasive prostate carcinoma in vivo. Furthermore, we report that PIK3CA mutation and PTEN loss coexist in patients with prostate cancer and can cooperate in vivo to accelerate disease progression via AKT–mTORC1/2 hyperactivation. Contrasting single mutants that slowly acquire castration-resistant prostate cancer (CRPC), concomitant Pik3ca mutation and Pten loss caused de novo CRPC. Thus, Pik3ca mutation and Pten deletion are not functionally redundant. Our findings indicate that PIK3CA mutation is an attractive prognostic indicator for prostate cancer that may cooperate with PTEN loss to facilitate CRPC in patients. Significance: We show PIK3CA mutation correlates with poor prostate cancer prognosis and causes prostate cancer in mice. Moreover, PIK3CA mutation and PTEN loss coexist in prostate cancer and can cooperate in vivo to accelerate tumorigenesis and facilitate CRPC. Delineating this synergistic relationship may present new therapeutic rognostic approaches to overcome castration/PI3K–AKT–mTORC1/2 inhibitor resistance. Cancer Discov 8(6) 764–79. ©2018 AACR. See related commentary by Triscott and Rubin, p. 682. This article is highlighted in the In This Issue feature, p. 663
Publisher: Informa UK Limited
Date: 05-07-2017
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3SM50646K
Publisher: Springer Science and Business Media LLC
Date: 22-03-2023
DOI: 10.1038/S41467-023-37161-0
Abstract: In heterogeneous head and neck cancer (HNC), subtype-specific treatment regimens are currently missing. An integrated analysis of patient HNC subtypes using single-cell sequencing and proteome profiles reveals an epithelial-mesenchymal transition (EMT) signature within the epithelial cancer-cell population. The EMT signature coincides with PI3K/mTOR inactivation in the mesenchymal subtype. Conversely, the signature is suppressed in epithelial cells of the basal subtype which exhibits hyperactive PI3K/mTOR signalling. We further identify YBX1 phosphorylation, downstream of the PI3K/mTOR pathway, restraining basal-like cancer cell proliferation. In contrast, YBX1 acts as a safeguard against the proliferation-to-invasion switch in mesenchymal-like epithelial cancer cells, and its loss accentuates partial-EMT and in vivo invasion. Interestingly, phospho-YBX1 that is mutually exclusive to partial-EMT, emerges as a prognostic marker for overall patient outcomes. These findings create a unique opportunity to sensitise mesenchymal cancer cells to PI3K/mTOR inhibitors by shifting them towards a basal-like subtype as a promising therapeutic approach against HNC.
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/2159-8290.22532957
Abstract: Supplemetary Material and Tables S1 - S7
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/2159-8290.22532960
Abstract: Supplementary Figure 7: Characterization of Pik3ca+/HR, Ptenfl/fl and Pik3ca+/HR Ptenfl/fl prostate tumors. Representative images of IHC to detect (A) PCNA and (B) Cleaved-caspase 3 (CC3) in Pik3ca+/HR, Ptenfl/fl and Pik3ca+/HR Ptenfl/fl prostate tissue 2 weeks post-castration compared to uncastrated, age-matched controls (scale bar: 50 um, n = 3). Mice were castrated when prostate carcinoma was prevalent Pik3ca+/HR = 400 d old, Ptenfl/fl = 200 d old and Pik3ca+/HR Ptenfl/fl =100 d old. Quantitative RT-PCR to detect (C) Nkx3.1 and (D) Pbsn mRNA in Wt prostate and Pik3ca+/HR, Ptenfl/fl and Pik3ca+/HR Ptenfl/fl stage-matched prostate carcinomas (n = 5). Error bars: SEM, *P .05 compared to Wt, or as indicated, one-way ANOVA with Tukey's multiple comparison test. (E) Western Blotting of protein lysates isolated from Wt prostate and stage-matched Pik3ca+/HR, Ptenfl/fl and Pik3ca+/HR Ptenfl/fl prostate carcinomas to detect total AKT, p-AKT Thr308 and p-AKT Ser473 (n = 3).
Publisher: Oxford University Press (OUP)
Date: 10-02-2015
Publisher: Oxford University Press (OUP)
Date: 06-1999
Abstract: As the colonic epithelium is physiologically exposed to butyrate and to activators of protein kinase C, we examined the effect of the protein kinase C signalling pathway on butyrate-induced expression of markers of differentiation. Activators and inhibitors of protein kinase C were used in combination with butyrate and effects on the expression of markers of differentiation examined in colon cancer cell lines. When the protein kinase C activator phorbol myristate acetate (100 nM) was added for 24 h prior to the addition of 2 mM butyrate, there was a synergistic increase in alkaline phosphatase activity (154 +/- 11% above that for butyrate alone, P = 0.003) in a concentration- and time-dependent manner. Butyrate-induced expression of carcinoembryonic antigen and interleukin-8, dome formation and cell turnover were also markedly augmented by pre-treatment with phorbol myristate acetate. A similar effect was observed with propionate or acetate (but not other differentiating agents), when phorbol myristate acetate and butyrate were added concurrently, or when other protein kinase C activators were used. Pharmacological inhibition of protein kinase C activity did not alter butyrate-induced alkaline phosphatase activity, but abrogated the augmentation induced by phorbol myristate acetate. We conclude that protein kinase C does not mediate the differentiating effects of butyrate on colon cancer cells, but its activation regulates butyrate-induced cellular differentiation.
Publisher: Elsevier BV
Date: 07-2015
DOI: 10.1016/J.SCITOTENV.2015.03.110
Abstract: Studies of C cycle alterations are extremely important to identify changes due to climate change, especially in the polar ecosystem. The objectives of this study were to (i) examine patterns of soil CO2-C and N2O-N emissions, and (ii) evaluate the quantity and quality of soil organic matter across a glacier retreat chronosequence in the Maritime Antarctica. Field measurements were carried out during January and February 2010 (summer season) along a retreating zone of the White Eagle Glacier, at King George Island, Maritime Antarctica. Soil s les (0-10cm) were collected along a 500-m transect at regular intervals to determine changes in soil organic matter. Field CO2-C emission measurements and soil temperature were carried out at regular intervals. In addition, greenhouse gas production potentials were assessed through 100days laboratory incubations. Soils exposed for a longer time tended to have greater concentrations of soluble salts and possess sandier textures. Total organic C (3.59gkg(-1)), total N (2.31gkg(-1)) and labile C (1.83gkg(-1)) tended to be lower near the glacier front compared with sites away from it, which is correlated with decreasing degree of humification of the soil organic matter with exposure time. Soil CO2-C emissions tended to increase with distance from the glacier front. On average, the presence of vegetation increased CO2-C emissions by 440%, or the equivalent of 0.633g of CO2-C m(-2)h(-1). Results suggest that newly exposed landsurfaces undergo soil formation with increasing labile C input from vegetation, accompanied by increasing soil CO2-C emissions. Despite the importance of exposure time on CO2-C production and emissions, there was no similar trend in soil N2O-N production potentials as a function of glacial retreat. For N2O, instead, the maximum production occurred in sites with the first stages of vegetation growth.
Publisher: Springer Science and Business Media LLC
Date: 13-09-2004
Publisher: Public Library of Science (PLoS)
Date: 13-04-2011
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/2159-8290.22532978.V1
Abstract: Supplementary Figure 1: PIK3CA mutations are predominantly missense mutations and PTEN mutation/loss predicts for poor prostate cancer patient survival. (A) Pie chart depicting the frequency of missense/nonsense mutations, in-frame deletions and fusion events in PIK3CA identified in the 9 prostate cancer genomic datasets assessed in Fig. 1A (3-10). (B) Kaplan-Meier plot comparing TCGA provisional prostate adenocarcinoma dataset with PTEN homozygous deletion, loss or mutation compared to the general population. PTEN age-adjusted COXPH HR: 0.47, P = 0.0026* (n = 492, s les with sequencing and CNA data only). Data was obtained from the TCGA data portal (tcga-data.nci.nih.gov/). PTEN copy number loss criteria Log R ratio {less than or equal to} -0.48, probe number {greater than or equal to} 10. Silent mutations were excluded.
Publisher: American Association for Cancer Research (AACR)
Date: 10-2005
Publisher: Wiley
Date: 05-2022
DOI: 10.1002/CTM2.810
Abstract: The risk of esophageal adenocarcinoma (EAC) is associated with gastro‐esophageal reflux disease (GERD) and obesity. Lipid metabolism‐targeted therapies decrease the risk of progressing from Barrett's esophagus (BE) to EAC, but the precise lipid metabolic changes and their roles in genotoxicity during EAC development are yet to be established. Esophageal biopsies from the normal epithelium (NE), BE, and EAC, were analyzed using concurrent lipidomics and proteomics ( n = 30) followed by orthogonal validation on independent s les using RNAseq transcriptomics ( n = 22) and immunohistochemistry (IHC, n = 80). The EAC cell line FLO‐1 was treated with FADS2 selective inhibitor SC26196, and/or bile acid cocktail, followed by immunofluorescence staining for γH2AX. Metabolism‐focused Reactome analysis of the proteomics data revealed enrichment of fatty acid metabolism, ketone body metabolism, and biosynthesis of specialized pro‐resolving mediators in EAC pathogenesis. Lipidomics revealed progressive alterations (NE‐BE‐EAC) in glycerophospholipid synthesis with decreasing triglycerides and increasing phosphatidylcholine and phosphatidylethanolamine, and sphingolipid synthesis with decreasing dihydroceramide and increasing ceramides. Furthermore, a progressive increase in lipids with C20 fatty acids and polyunsaturated lipids with ≥4 double bonds were also observed. Integration with transcriptome data identified candidate enzymes for IHC validation: Δ4‐Desaturase, Sphingolipid 1 (DEGS1) which desaturates dihydroceramide to ceramide, and Δ5 and Δ6‐Desaturases (fatty acid desaturases, FADS1 and FADS2), responsible for polyunsaturation. All three enzymes showed significant increases from BE through dysplasia to EAC, but transcript levels of DEGS1 were decreased suggesting post‐translational regulation. Finally, the FADS2 selective inhibitor SC26196 significantly reduced polyunsaturated lipids with three and four double bonds and reduced bile acid‐induced DNA double‐strand breaks in FLO‐1 cells in vitro. Integrated multiomics revealed sphingolipid and phospholipid metabolism rewiring during EAC development. FADS2 inhibition and reduction of the high polyunsaturated lipids effectively protected EAC cells from bile acid‐induced DNA damage in vitro, potentially through reduced lipid peroxidation.
Publisher: Elsevier BV
Date: 12-2018
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/2159-8290.22532969
Abstract: Supplementary Figure 4: Pik3caH1047R heterozygous oncogenic mutation causes p110alpha-dependent prostate cancer. Representative H& E images (scale bar: 100 um) for Pik3ca+/HR and Ptenfl/fl dorsolateral prostate and histograms displaying phenotype incidence for anterior (B) and ventral (C) prostate lobes from Pik3ca+/HR and Ptenfl/fl mice treated with vehicle, p110alpha�inhibitor (A66), p110beta inhibitor (TGX-221), pan-PI3K inhibitor (BKM120) or A66 + TGX-221 for 4 weeks. ND = not done. A66 and TGX-221 were generated in house by P.R.S. (University of Auckland, New Zealand) (14) and BKM120 was obtained from SYNkinase (Australia).
Publisher: Springer Science and Business Media LLC
Date: 17-09-2015
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/2159-8290.22532966
Abstract: Supplementary Figure 5: Pik3caH1047R mutation and Pten-deletion synergize to promote prostate cancer by increasing mTORC1/2 signaling. Histograms displaying phenotype incidence for anterior (A) and ventral (B) prostate lobes at 56 and 100 days of age. (C) Representative IHC images of Pik3ca+/HR Ptenfl/fl prostate tumors at 100 d stained to detect CK8, CK5 and SMA (n = 3, scale bar: 50 um). (D) Bar chart displaying total prostate weight normalised to body weight for Wt (n = 7), Pik3ca+/HR (n = 8), Ptenfl/fl (n = 8) and Pik3ca+/HR Ptenfl/fl (n = 7) 100 d old mice. Error bars: SEM, *P .05 compared to Wt or as indicated, one-way ANOVA with Tukey's multiple comparison test. (E) Quantitation of the apoptotic marker Cleaved-Caspase-3 (CC3) positive nuclei and (F) representative IHC images of CC3 staining in Pik3ca+/HR, Ptenfl/fl and Pik3ca+/HR Ptenfl/fl stage-matched invasive prostate carcinoma (scale bar: 50 um, n = 3, one-way ANOVA with Tukey's multiple comparison test. Error bars: SEM). (G) Representative IHC images of Pik3ca+/HR, Ptenfl/fl and Pik3ca+/HR Ptenfl/fl stage-matched invasive prostate carcinoma stained to detect p-AKT Thr308, p-RPS6 Ser235/236, p-4E-BP1 Thr37/46, p-AKT Ser473 and p-NDRG1 Thr346 (scale bar: 50 um). (H) Representative images of RNA in situ hybridisation (ISH) to detect positive (housekeeping gene PPIB, peptidylprolyl isomerase B) and negative (bacterial gene dapB) control probes to confirm RNA quality and the absence of background signal respectively (scale bar: 50 um, insert scale bar: 5 um).
Publisher: Impact Journals, LLC
Date: 11-10-2017
Publisher: Springer Science and Business Media LLC
Date: 12-2012
Abstract: The α-isoform of the Type 1A Phosphoinositide 3-kinases (PI3Kα) has protein kinase activity as well as phosphoinositide lipid kinase activity. The best described substrate for its protein kinase activity is its regulatory subunit, p85α, which becomes phosphorylated on Serine 608. Phosphorylation of Serine 608 has been reported to down-regulate its lipid kinase activity. We have assessed whether oncogenic mutants of PI3Kα, which have up-regulated lipid kinase activity, have altered levels of Serine 608 phosphorylation compared to wild type PI3Kα, and whether differential phosphorylation of Serine 608 contributes to increased activity of oncogenic forms of PI3Kα with point mutations in the helical or the kinase domains. Despite markedly increased lipid kinase activity, protein kinase activity was not altered in oncogenic compared to wild type forms of PI3Kα. By manipulating levels of phosphorylation of Serine 608 in vitro , we found no evidence that the protein kinase activity of PI3Kα affects its phosphoinositide lipid kinase activity in either wild-type or oncogenic mutants of PI3Kα. Phosphorylation of p85α S608 is not a significant regulator of wild-type or oncogenic PI3Kα lipid kinase activity.
Publisher: Springer Science and Business Media LLC
Date: 26-09-2007
DOI: 10.1245/S10434-007-9550-1
Abstract: The use of neoadjuvant therapy, in particular chemoradiotherapy (CRT), in the treatment of esophageal cancer (EC) remains controversial. The ability to predict treatment response in an in idual EC patient would greatly aid therapeutic planning. Gene expression profiles of EC were measured and relationship to therapeutic response assessed. Tumor biopsy s les taken from 46 EC patients before neoadjuvant CRT were analyzed on 10.5K cDNA microarrays. Response to treatment was assessed and correlated to gene expression patterns by using a support vector machine learning algorithm. Complete clinical response at conclusion of CRT was achieved in 6 of 21 squamous cell carcinoma (SCC) and 11 of 25 adenocarcinoma (AC) patients. CRT response was an independent prognostic factor for survival (P < .001). A range of support vector machine models incorporating 10 to 1000 genes produced a predictive performance of tumor response to CRT peaking at 87% in SCC, but a distinct positive prediction profile was unobtainable for AC. A 32-gene classifier was produced, and by means of this classifier, 10 of 21 SCC patients could be accurately identified as having disease with an incomplete response to therapy, and thus unlikely to benefit from neoadjuvant CRT. Our study identifies a 32-gene classifier that can be used to predict response to neoadjuvant CRT in SCC. However, because of the molecular ersity between the two histological subtypes of EC, when considering the AC and SCC s les as a single cohort, a predictive profile could not be resolved, and a negative predictive profile was observed for AC.
Publisher: Wiley
Date: 12-1989
Abstract: Murine bone marrow-derived macrophages (BMM) undergo DNA synthesis in response to growth factors such as colony stimulating factor-1 (CSF-1) and granulocyte-macrophage CSF (GM-CSF). These macrophages can also be "activated," but without subsequent DNA synthesis, by a number of other agents, including lipopolysaccharide (LPS), concanavalin A, zymosan, formyl-methionyl-leucyl-phenylalanine (FMLP), and the Ca2+ ionophore, A23187. When BMM are treated with a range of stimuli, there is some, although not perfect, correlation between transient elevations in both c-myc mRNA and c-fos mRNA levels and increases in DNA synthesis. However, enhanced DNA synthesis and oncogene expression are readily dissociated from rises in inositol phosphates and, by implication, phospholipase C-mediated hydrolysis of phosphatidyl inositol 4,5-bisphosphate. Superoxide formation in BMM can also be dissociated from the other responses and does not necessarily depend on protein kinase C activation.
Publisher: Springer Science and Business Media LLC
Date: 04-04-2012
Publisher: American Association for Cancer Research (AACR)
Date: 02-2015
DOI: 10.1158/2159-8290.CD-14-0856
Abstract: Phosphatidylinositide 3′ (PI3′)-lipid signaling cooperates with oncogenic BRAFV600E to promote melanomagenesis. Sustained PI3′-lipid production commonly occurs via silencing of the PI3′-lipid phosphatase PTEN or, less commonly, through mutational activation of PIK3CA, encoding the 110-kDa catalytic subunit of PI3′-kinase-α (PI3Kα). To define the PI3K catalytic isoform dependency of BRAF-mutated melanoma, we used pharmacologic, isoform-selective PI3K inhibitors in conjunction with melanoma-derived cell lines and genetically engineered mouse (GEM) models. Although BRAFV600E/PIK3CAH1047R melanomas were sensitive to the antiproliferative effects of selective PI3Kα blockade, inhibition of BRAFV600E/PTENNull melanoma proliferation required combined blockade of PI3Kα, PI3Kδ, and PI3Kγ, and was insensitive to PI3Kβ blockade. In GEM models, isoform-selective PI3K inhibition elicited cytostatic effects, but significantly potentiated melanoma regression in response to BRAFV600E pathway–targeted inhibition. Interestingly, PI3K inhibition forestalled the onset of MEK inhibitor resistance in two independent GEM models of BRAFV600E-driven melanoma. These results suggest that combination therapy with PI3K inhibitors may be a useful strategy to extend the duration of clinical response of patients with BRAF-mutated melanoma to BRAFV600E pathway–targeted therapies. Significance: Although BRAFV600E pathway–targeted therapies elicit melanoma regression, the onset of drug resistance limits the durability of response. Here, we show that combined treatment with PI3K inhibitors significantly forestalled the onset of MEK1/2 inhibitor–resistant disease in BRAF-mutated GEM melanoma models. These results provide a conceptual framework for the combined deployment of BRAFV600E plus PI3K pathway–targeted inhibitors in the treatment of a subset of patients with BRAF-mutated melanoma. Cancer Discov 5(2) 143–53. ©2014 AACR. This article is highlighted in the In This Issue feature, p. 97
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/2159-8290.22532963
Abstract: Supplementary Figure 6: Pik3ca+/HR and Ptenfl/fl prostate cancers acquire CRPC, while Pik3ca+/HR Ptenfl/fl mutants are resistant to castration. (A) Representative H& E images of Pik3ca+/HR, Ptenfl/fl and Pik3ca+/HR Ptenfl/fl anterior (AP) and ventral (VP) prostate lobes post-castration (scale bar: 50 um, n = 3). (B) Representative IHC images of Pik3ca+/HR, Ptenfl/fl and Pik3ca+/HR Ptenfl/fl prostate tissue stained to detect Androgen receptor (AR) 2 weeks post-castration compared to uncastrated, age-matched controls (scale bar: 50 um, n = 3). Mice were castrated when prostate carcinoma was prevalent Pik3ca+/HR = 400 d old, Ptenfl/fl = 200 d old and Pik3ca+/HR Ptenfl/fl = 100 d old. Insert displays positive AR nuclei (arrows) in Pik3ca+/HR Ptenfl/fl compound mutants (scale bar: 5 um). (C) Bar chart displaying total prostate weight normalised to body weight for Pik3ca+/HR mice 0, 2 and 42 weeks post-castration (n = 8, 7 and 7, respectively). Error bars: SEM, *P .05 compared to 0 weeks post-castration, or as indicated, one-way ANOVA with Tukey's multiple comparison test. (D) Representative H& E images of Pik3ca+/HR mice 0, 2 and 42 weeks post-castration (scale bar: 100 um). Mice were castrated at 100 d of age.
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/1535-7163.22521234.V1
Abstract: Figure S3 shows extended correlation analysis in haematopoietic and lymphoid, breast and lung cancer cell lines
Publisher: Elsevier BV
Date: 10-1982
DOI: 10.1016/0022-1759(82)90058-8
Abstract: A technique for detecting the nitroblue tetrazolium-reducing activity of human polymorphonuclear leukocyte enzymes separated on polyacrylamide gels is reported. Slices of gel are incubated in buffer containing nitroblue tetrazolium and either NADPH or NADH. Enzymes capable of reducing nitroblue tetrazolium form a dark band due to the formation of the insoluble formazan. By this technique the soluble fraction of human polymorphonuclear leukocyte sonicates was shown to contain several enzymes capable of reducing nitroblue tetrazolium in the presence of NADPH and NADH.
Publisher: Springer Science and Business Media LLC
Date: 24-02-2021
DOI: 10.1038/S41598-021-83979-3
Abstract: The prevalence and dire implications of mutations in the tumour suppressor, p53, highlight its appeal as a chemotherapeutic target. We recently showed that impairing cellular antioxidant systems via inhibition of SLC7A11, a component of the system x c − cystine-glutamate antiporter, enhances sensitivity to mutant-p53 targeted therapy, APR-246. We investigated whether this synergy extends to other genes, such as those encoding enzymes of the pentose phosphate pathway (PPP). TKT, one of the major enzymes of the PPP, is allegedly regulated by NRF2, which is in turn impaired by accumulated mutant-p53 protein. Therefore, we investigated the relationship between mutant-p53, TKT and sensitivity to APR-246. We found that mutant-p53 does not alter expression of TKT, nor is TKT modulated directly by NRF2, suggesting a more complex mechanism at play. Furthermore, we found that in p53null cells, knockdown of TKT increased sensitivity to APR-246, whilst TKT overexpression conferred resistance to the drug. However, neither permutation elicited any effect on cells overexpressing mutant-p53 protein, despite mediating oxidative stress levels in a similar fashion to that in p53-null cells. In sum, this study has unveiled TKT expression as a determinant for sensitivity to APR-246 in p53-null cells.
Publisher: Wiley
Date: 09-2014
DOI: 10.1111/NYAS.12531
Abstract: The following, from the 12th OESO World Conference: Cancers of the Esophagus, includes commentaries on translational research on Barrett's esophagus that address evidence for genetic instability in esophageal cancer the role of microsatellite instability the use of histologic and serum Doublecortin-like kinase 1 expression for progression of Barrett's esophagus to adenocarcinoma the oxidative stress in Barrett's tumorigenesis the genomic alterations in esophageal cancer in vivo modeling in Barrett's esophagus epigenetic and transcriptional regulation in Barrett's esophagus and esophageal adenocarcinoma and normal and disordered regeneration in Barrett's esophagus.
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/1535-7163.22521228.V1
Abstract: Figure S5 shows MYC directly regulates SLC7A11 levels and APR-246 sensitivity.
Publisher: Wiley
Date: 15-09-2020
DOI: 10.1002/PATH.5528
Publisher: American Society for Clinical Investigation
Date: 02-2012
DOI: 10.1172/JCI59309
Publisher: American Association for Cancer Research (AACR)
Date: 05-2011
DOI: 10.1158/1078-0432.CCR-10-2915
Abstract: Purpose: Patients presenting with locally advanced rectal cancer currently receive preoperative radiotherapy with or without chemotherapy. Although pathologic complete response is achieved for approximately 10% to 30% of patients, a proportion of patients derive no benefit from this therapy while being exposed to toxic side effects of treatment. Therefore, there is a strong need to identify patients who are unlikely to benefit from neoadjuvant therapy to help direct them toward alternate and ultimately more successful treatment options. Experimental Design: In this study, we obtained expression profiles from pretreatment biopsies for 51 rectal cancer patients. All patients underwent preoperative chemoradiotherapy, followed by resection of the tumor 6 to 8 weeks posttreatment. Gene expression and response to treatment were correlated, and a supervised learning algorithm was used to generate an original predictive classifier and validate previously published classifiers. Results: Novel predictive classifiers based on Mandard's tumor regression grade, metabolic response, TNM (tumor node metastasis) downstaging, and normal tissue expression profiles were generated. Because there were only 7 patients who had minimal treatment response (& % residual tumor), expression profiles were used to predict good tumor response and outcome. These classifiers peaked at 82% sensitivity and 89% specificity however, classifiers with the highest sensitivity had poor specificity, and vice versa. Validation of predictive classifiers from previously published reports was attempted using this cohort however, sensitivity and specificity ranged from 21% to 70%. Conclusions: These results show that the clinical utility of microarrays in predictive medicine is not yet within reach for rectal cancer and alternatives to microarrays should be considered for predictive studies in rectal adenocarcinoma. Clin Cancer Res 17(9) 3039–47. ©2011 AACR.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 16-09-2022
Abstract: The mechanism of action of eprenetapopt (APR-246, PRIMA-1 MET ) as an anticancer agent remains unresolved, although the clinical development of eprenetapopt focuses on its reported mechanism of action as a mutant-p53 reactivator. Using unbiased approaches, this study demonstrates that eprenetapopt depletes cellular antioxidant glutathione levels by increasing its turnover, triggering a nonapoptotic, iron-dependent form of cell death known as ferroptosis. Deficiency in genes responsible for supplying cancer cells with the substrates for de novo glutathione synthesis ( SLC7A11 , SHMT2 , and MTHFD1L ), as well as the enzymes required to synthesize glutathione ( GCLC and GCLM ), augments the activity of eprenetapopt. Eprenetapopt also inhibits iron-sulfur cluster biogenesis by limiting the cysteine desulfurase activity of NFS1, which potentiates ferroptosis and may restrict cellular proliferation. The combination of eprenetapopt with dietary serine and glycine restriction synergizes to inhibit esophageal xenograft tumor growth. These findings reframe the canonical view of eprenetapopt from a mutant-p53 reactivator to a ferroptosis inducer.
Publisher: Wiley
Date: 21-03-2011
DOI: 10.1111/J.1440-1746.2010.06602.X
Abstract: Barrett's esophagus is an acquired metaplastic abnormality in which the normal stratified squamous epithelium lining of the esophagus is replaced by an intestinal-like columnar epithelium. While in itself a benign and asymptomatic disorder, the clinical importance of this relatively common condition relates to its role as a precursor lesion to esophageal adenocarcinoma, the incidence of which has dramatically increased in Western populations in recent years. Although known to arise as a consequence of chronic gastroesophageal reflux, the cellular and molecular mechanisms underlying development Barrett's esophagus and its progression to cancer remain unclear.
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/1535-7163.22521240
Abstract: Figure S1 shows TP53 mutation alone is not predictive of cancer cell response to PRIMA-1.
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/2159-8290.22532978
Abstract: Supplementary Figure 1: PIK3CA mutations are predominantly missense mutations and PTEN mutation/loss predicts for poor prostate cancer patient survival. (A) Pie chart depicting the frequency of missense/nonsense mutations, in-frame deletions and fusion events in PIK3CA identified in the 9 prostate cancer genomic datasets assessed in Fig. 1A (3-10). (B) Kaplan-Meier plot comparing TCGA provisional prostate adenocarcinoma dataset with PTEN homozygous deletion, loss or mutation compared to the general population. PTEN age-adjusted COXPH HR: 0.47, P = 0.0026* (n = 492, s les with sequencing and CNA data only). Data was obtained from the TCGA data portal (tcga-data.nci.nih.gov/). PTEN copy number loss criteria Log R ratio {less than or equal to} -0.48, probe number {greater than or equal to} 10. Silent mutations were excluded.
Publisher: Elsevier BV
Date: 04-0005
DOI: 10.1111/J.1432-0436.2005.00015.X
Abstract: Frizzled (FZD) receptors have a conserved N-terminal extracellular cysteine-rich domain that interacts with Wnts and co-expression of the receptor ectodomain can antagonize FZD-mediated signalling. Using the ectodomain as an antagonist we have modulated endogenous FZD7 signalling in the moderately differentiated colon adenocarcinoma cell line, SK-CO-1. Unlike the parental cell line, which grows as tightly associated adherent cell clusters, the FZD7 ectodomain expressing cells display a spread out morphology and grow as a monolayer in tissue culture. This transition in morphology was associated with decreased levels of plasma membrane-associated E-cadherin and beta-catenin, localized increased levels of vimentin and redistribution of alpha6 integrin to cellular processes in the FZD7 ectodomain expressing cells. The morphological and phenotype changes induced by FZD7 ectodomain expression in SK-CO-1 cells is thus consistent with the cells undergoing an epithelial-to-mesenchymal-like transition. Furthermore, initiation of tumor formation in a xenograft tumor growth assay was attenuated in the FZD7 ectodomain expressing cells. Our results indicate a pivotal role for endogenous FZD7 in morphology transitions that are associated with colon tumor initiation and progression.
Publisher: Impact Journals, LLC
Date: 09-05-2016
Publisher: Springer Science and Business Media LLC
Date: 23-01-2014
DOI: 10.1186/BCR3605
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/2159-8290.22532972
Abstract: Supplementary Figure 3: Characterization of Pik3ca-mutated and Pten-deleted prostate hyperplasia and carcinoma. (A) IHC to detect the apoptotic marker Cleaved-Caspase-3 (CC3) in Wt, Pik3ca+/HR and Ptenfl/fl mice at 400 d (scale bar: 50 um). (B) Quantitation of CC3-positive nuclei in Wt, Pik3ca+/HR and Ptenfl/fl prostate epithelium (n = 3, *P .05 compared to Wt, or as indicated, one-way ANOVA with Tukey's multiple comparison test, ns = not significant. Error bars: SEM). (C) IHC to detect CK5 and CK8 in Pik3ca+/HR and Ptenfl/fl carcinomas (representative images from 3 prostates per genotype, scale bar: 50 um). (D) Representative IHC images to detect PTEN, mTORC1 signaling components (p-AKT Thr308, p-RPS6 Ser235/236 and p-4E-BP1 Thr37/46) and mTORC2 substrates (p-AKT Ser473 and p-NDRG1 Thr346) in Pik3ca+/HR and Ptenfl/fl hyperplastic lesions (n = 3, scale bar: 50 um). IHC quantitation for (E) p-AKT Thr308, (F) p-RPS6 Ser235/236, (G) p-4E-BP1 Thr37/46, (H) p-AKT Ser473 and (I) p-NDRG1 Thr346 in Pik3ca+/HR and Ptenfl/fl prostate hyperplastic lesions (n = 3, Error bars: SEM, *P 0.05, unpaired, two-tailed t-test).
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/1535-7163.22521231.V1
Abstract: Figure S4 shows the effects of p53 overexpression and repression on SLC7A11 mRNA expression.
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/2159-8290.22532975
Abstract: Supplementary Figure 2: Heterozygous Pik3caH1047R oncogenic mutation causes invasive prostate cancer in mice that is phenotypically distinct to Pten-null prostate cancer. (A) Sequencing cDNA isolated from PBiCre+/- Pik3ca+/HR prostate tissue confirmed heterozygosity at known silent base changes within mutant exon 20 adjacent to exon 19, indicating recombination has occurred. (B) allele-specific PCR of cDNA isolated from PBiCre+/- prostate tissue expressing either Pik3ca+/+ (Wt) or Pik3ca+/HR alleles (as previously described (13)) revealed the presence of the mutant exon 20 in PBiCre+/- Pik3ca+/HR prostate cDNA, but not in PBiCre+/- Wt prostate cDNA. (C) Representative H& E images of PBiCre+/- Wt, Pik3ca+/HR and Ptenfl/fl ventral and anterior prostate epithelium at 400 d (scale bar: 100 um). Phenotype incidence plots for PBiCre+/- Wt, Pik3ca+/HR and Ptenfl/fl ventral (D) and anterior (E) prostate lobes. VP = Ventral prostate, AP = anterior prostate, PIN = prostate intraepithelial neoplasia. (F) IHC to detect SMA in Wt, Pik3ca+/HR and Ptenfl/fl mice at 400 d (scale bar: 50 um). (G) Quantitation of PCNA-positive nuclei in PBiCre+/- Pik3ca+/HR and Ptenfl/fl prostate hyperplastic lesions. *P .001, one-way ANOVA with Tukey's multiple comparison test, n = 3. Error bars: SEM.
Publisher: American Association for Cancer Research (AACR)
Date: 31-10-2013
DOI: 10.1158/0008-5472.CAN-13-0681
Abstract: Adenocarcinoma of the lung, a leading cause of cancer death, frequently displays mutational activation of the KRAS proto-oncogene but, unlike lung cancers expressing mutated EGFR, ROS1, or ALK, there is no pathway-targeted therapy for patients with KRAS-mutated lung cancer. In preclinical models, expression of oncogenic KRASG12D in the lung epithelium of adult mice initiates development of lung adenocarcinoma through activation of downstream signaling pathways. In contrast, mutationally activated BRAFV600E, a KRAS effector, fails to initiate lung carcinogenesis despite highly efficient induction of benign lung tumorigenesis. To test if phosphoinositide 3-kinase (PI3K)-α (PIK3CA), another KRAS effector, might cooperate with oncogenic BRAFV600E to promote lung cancer progression, we used mice carrying a conditional allele of Pik3ca that allows conversion of the wild-type catalytic subunit of PIK3CA to mutationally activated PIK3CAH1047R. Although expression of PIK3CAH1047R in the lung epithelium, either alone or in combination with PTEN silencing, was without phenotype, concomitant expression of BRAFV600E and PIK3CAH1047R led to dramatically decreased tumor latency and increased tumor burden compared with BRAFV600E alone. Most notably, coexpression of BRAFV600E and PIK3CAH1047R elicited lung adenocarcinomas in a manner reminiscent of the effects of KRASG12D. These data emphasize a role for PI3K signaling, not in lung tumor initiation per se, but in both the rate of tumor growth and the propensity of benign lung tumors to progress to a malignant phenotype. Finally, biologic and biochemical analysis of BRAFV600E/PIK3CAH1047R-expressing mouse lung cancer cells revealed mechanistic clues about cooperative regulation of the cell- ision cycle and apoptosis by these oncogenes. Cancer Res 73(21) 6448–61. ©2013 AACR.
Publisher: Elsevier BV
Date: 1992
DOI: 10.1016/0006-291X(92)91792-O
Abstract: Preexposure of human monocytes to recombinant human interleukin-4 (IL-4) suppressed the respiratory burst response to a number of different stimuli, including phorbol myristate acetate, zymosan, platelet-activating factor and the chemotactic peptide, f-met-leu-phe. Under similar conditions, the respiratory burst of murine macrophages was enhanced by preexposure to recombinant murine IL-4. By conducting our studies on cells from different species under similar conditions we have demonstrated that there is a significant disparity in the effects of IL-4 on human and murine macrophages thus providing an explanation for some apparent inconsistencies in the literature and highlighting the need for caution when extrapolating data across species barriers.
Publisher: Cold Spring Harbor Laboratory
Date: 30-05-2017
DOI: 10.1101/143388
Abstract: Hyperactivation of the PI3K signaling is common in human cancers, including gliomas, but the precise role of the pathway in glioma biology remains to be determined. Some limited understanding of PI3K signaling in brain cancer come from studies on neural stem rogenitor cells (NSPCs) where signals transmitted via the PI3K pathway cooperate with other intracellular pathways and downstream transcription factors to regulate NSPC proliferation. To investigate the role for the PI3K pathway in glioma initiation and development, we generated a mouse model targeting the inducible expression of a Pik3ca H1047A oncogenic mutation and simultaneous deletion of the PI3K negative regulator, Pten, in NSPCs. We show that the expression of a Pik3ca H1047A was sufficient to initiate tumorigenesis but that simultaneous loss of Pten, was required for the development of invasive, high-grade glioma. Mutant NSPCs exhibited enhanced neurosphere forming capacity which correlated with increased Wnt signaling. We also show that loss of CREB in Pik3ca-PTEN tumors led to a longer symptom-free survival in mice. Taken together, our findings present a novel mouse model for high-grade glioma with which we demonstrate that the PI3K pathway is important for initiation of tumorigenesis and that disruption of downstream CREB signaling attenuates tumor expansion.
Publisher: American Association for Cancer Research (AACR)
Date: 15-06-2006
DOI: 10.1158/1078-0432.CCR-06-0800
Abstract: Purpose: A very high frequency of somatic mutations in the transforming growth factor-β signaling component km23 has been reported in a small series of ovarian cancers (8 of 19, 42%). Functional studies showed that some mutations disrupt km23 function, resulting in aberrant transforming growth factor-β signaling and presumably enhanced tumorigenicity. If verified, this would elevate mutation of km23 as the single most frequent somatic event in ovarian cancer. Experimental Design: We sought to verify the frequency of silencing of km23 among 104 primary ovarian cancers (49 serous, 18 mucinous, 29 endometrioid/clear cell, and 8 undifferentiated) as well as 72 breast and 61 colorectal cancers by undertaking both somatic mutation and promoter methylation analyses. All four exons of km23 were in idually lified from genomic DNA with primers complementary to surrounding intronic sequences and analyzed by single-stranded conformational polymorphism analysis. Results: Two germ line polymorphisms were identified, but none of the 237 tumors analyzed harbored somatic km23 mutations. In addition, promoter methylation analysis showed that in all cases, the 5′ CpG island was unmethylated. Conclusions: Our data suggest that silencing of km23, either through somatic genetic mutation or promoter hypermethylation, is rare in ovarian, breast, and colorectal cancers.
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/1535-7163.22521225.V1
Abstract: Gene List from siRNA screen with APR-246 growth inhibition in H1299 p53-null (Sheet 1) and p53-R273H (Sheet 2)
Publisher: Elsevier BV
Date: 12-2015
Publisher: SAGE Publications
Date: 10-2001
DOI: 10.1177/074873001129002178
Abstract: Light exposure was measured in 30 permanent night nurses to determine if specific light/dark profiles could be associated with a better circadian adaptation. Circadian adaptation was defined as a significant shift in the timing of the episode of melatonin secretion into the daytime. Light exposure was continuously recorded with ambulatory wrist monitors for 56 h, including 3 consecutive nights of work. Participants were then admitted to the laboratory for 24 h where urine was collected every 2 h under dim light for the determination of 6-sulphatoxymelatonin concentration. Cosinor analysis was used to estimate the phase position of the episode of melatonin secretion. Five participants showed a circadian adaptation by phase delay (“delayed participants”) and 3 participants showed a circadian adaptation by phase advance (“advanced participants”). The other 22 participants had a timing of melatonin secretion typical of day-oriented people (“nonshifters”). There was no significant difference between the 3 groups for total light exposure or for bright light exposure in the morning when traveling home. However, the 24-h profiles of light exposure were very distinctive. The timing of the main sleep episode was associated with the timing of light exposure. Delayed participants, however, slept in darker bedrooms, and this had a major impact on their profile of light/dark exposure. Delayed and advanced participants scored as evening and morning types, respectively, on a morningness-eveningness scale. This observation suggests that circadian phase prior to night work may contribute to the initial step toward circadian adaptation, later reinforced by specific patterns of light exposure.
Publisher: American Association for Cancer Research (AACR)
Date: 14-11-2017
DOI: 10.1158/0008-5472.CAN-17-2210
Abstract: New treatments for triple-negative breast cancer (TNBC) are urgently needed. Despite there being little evidence of clinical activity as single-agent therapies, we show that dual blockade of PI3Kα and CDK4/6 is synergistically effective against multiple RB1-wild-type TNBC models. Combined PI3Kα and CDK4/6 inhibition significantly increased apoptosis, cell-cycle arrest, and tumor immunogenicity and generated immunogenic cell death in human TNBC cell lines. Combination treatment also significantly improved disease control in human xenograft models compared with either monotherapy. Combined PI3Kα and CDK4/6 inhibition significantly increased tumor-infiltrating T-cell activation and cytotoxicity and decreased the frequency of immunosuppressive myeloid-derived suppressor cells in a syngeneic TNBC mouse model. Notably, combined PI3Kα and CDK4/6 inhibition, along with inhibition of immune checkpoints PD-1 and CTLA-4, induced complete and durable regressions (& year) of established TNBC tumors in vivo. Overall, our results illustrate convergent mechanisms of PI3Kα and CDK4/6 blockade on cell-cycle progression, DNA damage response, and immune-modulation and may provide a novel therapeutic approach for TNBC. Cancer Res 77(22) 6340–52. ©2017 AACR.
Publisher: Wiley
Date: 05-07-2018
DOI: 10.1111/NYAS.13916
Abstract: Barrett's esophagus (BE) is clinically significant, as it is the only known precursor lesion for esophageal adenocarcinoma. To develop improved therapies for the treatment of BE, a greater understanding of the disease process at the molecular genetic level is needed. However, achieving a greater understanding will require improved preclinical models so that the disease process can be more closely studied and novel therapies can be tested. Our concise review highlights progress in the development of preclinical models for the study of BE and identifies the most suitable model in which to test novel therapies.
Publisher: Wiley
Date: 03-2016
DOI: 10.1111/CODI.13207
Abstract: Approximately 20% of patients treated with neoadjuvant chemoradiotherapy (nCRT) for locally advanced rectal cancer achieve a pathological complete response (pCR) while the remainder derive the benefit of improved local control and downstaging and a small proportion show a minimal response. The ability to predict which patients will benefit would allow for improved patient stratification directing therapy to those who are likely to achieve a good response, thereby avoiding ineffective treatment in those unlikely to benefit. A systematic review of the English language literature was conducted to identify pathological factors, imaging modalities and molecular factors that predict pCR following chemoradiotherapy. PubMed, MEDLINE and Cochrane Database searches were conducted with the following keywords and MeSH search terms: 'rectal neoplasm', 'response', 'neoadjuvant', 'preoperative chemoradiation', 'tumor response'. After review of title and abstracts, 85 articles addressing the prediction of pCR were selected. Clear methods to predict pCR before chemoradiotherapy have not been defined. Clinical and radiological features of the primary cancer have limited ability to predict response. Molecular profiling holds the greatest potential to predict pCR but adoption of this technology will require greater concordance between cohorts for the biomarkers currently under investigation. At present no robust markers of the prediction of pCR have been identified and the topic remains an area for future research. This review critically evaluates existing literature providing an overview of the methods currently available to predict pCR to nCRT for locally advanced rectal cancer. The review also provides a comprehensive comparison of the accuracy of each modality.
Publisher: Wiley
Date: 17-05-2012
DOI: 10.1111/J.1445-2197.2011.05789.X
Abstract: Chemotherapy is being administered to an increasing number of patients with colorectal liver metastases (CRLM), whether they have resectable disease or not. Although this may be appropriate to downstage patients with unresectable disease, and offers theoretical advantages to those who have resectable disease, there is a price to be paid in the development of chemotherapy‐induced hepatic injuries (CIHI). These include chemotherapy‐associated fatty liver diseases and sinusoidal injuries. The main chemotherapeutic agents currently used in the adjuvant setting for colorectal carcinoma, and the neoadjuvant treatment of CRLM include 5‐flurouracil, oxaliplatin and irinotecan, and while there are non‐specific and overlapping injury profiles, oxaliplatin does appear to be primarily associated with sinusoidal injury and irinotecan with steatohepatitis. In this review, the rationale for administering chemotherapy to patients with CRLM is presented, and the problems this brings are outlined. The specific injury patterns will be detailed, as well as the data correlating specific chemotherapy regimens to these injury patterns. Finally, the clinical outcomes of patients with CRLM who undergo neoadjuvant chemotherapy followed by hepatic resection will be considered. The need for methods to identify patients at risk of CIHI and to recognize established CIHI prior to surgery will be emphasized.
Publisher: Impact Journals, LLC
Date: 21-02-2017
Publisher: Elsevier BV
Date: 05-2012
Publisher: Elsevier BV
Date: 05-2010
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/1535-7163.22521234
Abstract: Figure S3 shows extended correlation analysis in haematopoietic and lymphoid, breast and lung cancer cell lines
Publisher: Elsevier BV
Date: 2021
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/1535-7163.22521237
Abstract: Figure S2 shows APR-246 and PX-12 activity correlate in CTRPv2 and their impact on mutant-p53 thermostability.
Publisher: American Association for Cancer Research (AACR)
Date: 03-04-2023
DOI: 10.1158/1535-7163.22521231
Abstract: Figure S4 shows the effects of p53 overexpression and repression on SLC7A11 mRNA expression.
Publisher: Portland Press Ltd.
Date: 04-2014
DOI: 10.1042/BSR20130133
Abstract: Oncogenic mutations in PIK3CA lead to an increase in intrinsic phosphoinositide kinase activity, but it is thought that increased access of PI3Kα (phosphoinositide 3-kinase α) to its PM (plasma membrane) localized substrate is also required for increased levels of downstream PIP3/Akt [phosphoinositide-3,4,5-trisphosphate/also called PKB (protein kinase B)] signalling. We have studied the subcellular localization of wild-type and the two most common oncogenic mutants of PI3Kα in cells maintained in growth media, and starved or stimulated cells using a novel method in which PI3Kα is pre-formed as a 1:1 p110α:p85α complex in vitro then introduced into live cells by microinjection. Oncogenic E545K and H1047R mutants did not constitutively interact with membrane lipids in vitro or in cells maintained in 10% (v/v) FBS. Following stimulation of RTKs (receptor tyrosine kinases), microinjected PI3Kα was recruited to the PM, but oncogenic forms of PI3Kα were not recruited to the PM to a greater extent and did not reside at the PM longer than the wild-type PI3Kα. Instead, the E545K mutant specifically bound activated Cdc42 in vitro and microinjection of E545K was associated with the formation of cellular protrusions, providing some preliminary evidence that changes in protein–protein interactions may play a role in the oncogenicity of the E545K mutant in addition to the well-known changes in lipid kinase activity.
Publisher: Humana Press
Date: 2012
DOI: 10.1007/978-1-61779-815-3_5
Abstract: Proliferation in mouse oesophageal epithelial cells is confined to the basal layer of the epithelium. Within this population, it is possible to discriminate different sub-populations using a combination of cell kinetic studies and functional assays. In particular, it is possible to distinguish basal epithelial cells, which are post-mitotic and destined to leave the basal layer and differentiate compared with those cells that remain in the cycling pool. Within the cycling basal population, there appears to be a hierarchy with respect to the rate of cell turnover which may reflect a hierarchy of "stemness", although it has not been possible to demonstrate functional differences between these populations using current in vivo tissue reconstitution assays. The aim of this chapter is to describe the development of a quantitative in vivo tissue reconstitution assay to assess the potency of candidate stem cell populations within the mouse oesophageal epithelium.
Publisher: Elsevier BV
Date: 05-2001
DOI: 10.1016/S0304-3835(01)00428-1
Abstract: A polymerase chain reaction-based approach was used to study the expression of Wnt genes in human colon carcinoma tissue and normal colon mucosa. In a number of cases Wnts 2, 4, 5a, 6 and/or 7a were found to be more highly expressed in colon carcinoma tissue compared to surrounding normal-appearing mucosa from the same patients. Wnts 4, 5a, 6 and 7a, but not 2, were also found to be expressed in colon cancer cell lines. The increased levels of expression of these Wnt genes in tumor tissue may indicate their possible involvement in human colon tumorigenesis.
Publisher: Springer Science and Business Media LLC
Date: 18-02-2015
DOI: 10.1245/S10434-015-4425-3
Abstract: Recently, there has been an increase in the availability of targeted molecular therapies for cancer treatment. The application of these approaches to esophageal cancer, however, has been h ered by the relative lack of appropriate models for preclinical testing. Patient-derived tumor xenograft (PDTX) models are gaining popularity for studying many cancers. Unfortunately, it has proven difficult to generate xenografts from esophageal cancer using these models. The purpose of this study was to improve the engraftment efficiency of esophageal PDTXs. Fresh pieces of esophageal tumors obtained from endoscopic biopsies or resected specimens were collected from 23 patients. The tumors were then coated in Matrigel and transplanted in immunocompromised mice subcutaneously (n = 6) and/or using a novel implantation technique whereby the tumor is placed in a dorsal intramuscular pocket (n = 18). They are then monitored for engraftment. With the novel intramuscular technique, successful engraftment was achieved for all 18 patient tumors. Among these PDTXs, 13 recapitulated the original patient tumors with respect to degree of differentiation, molecular and genetic profiles, and chemotherapeutic response. Lymphomatous transformation was observed in the other five PDTXs. Successful engraftment was achieved for only one of six patient tumors using the classic subcutaneous approach. We achieved a much higher engraftment rate of PDTXs using our novel intramuscular transplant technique than has been reported in other published studies. It is hoped that this advancement will help expedite the development and testing of new therapies for esophageal cancer.
Location: United States of America
Location: United States of America
No related grants have been discovered for Wayne Phillips.