ORCID Profile
0000-0001-9283-9978
Current Organisations
Peter MacCallum Cancer Centre
,
University of Melbourne
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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: 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: Elsevier BV
Date: 12-2004
Publisher: Informa UK Limited
Date: 19-09-2013
DOI: 10.4161/CBT.25362
Publisher: Elsevier BV
Date: 10-2007
DOI: 10.1053/J.GASTRO.2007.06.061
Abstract: The luminal microenvironment including acid and nitric oxide (NO) has been implicated in Barrett's esophagus carcinogenesis. We investigated the ability of acid and NO to induce DNA damage in esophageal cells. Transformed and primary Barrett's esophagus and adenocarcinoma cells were exposed to either acid, (pH 3.5), +/- antioxidant or NO from a donor or generated by acidification of nitrite in the presence of ascorbate +/- NO scavenger. Phosphorylation of histone H2AX and the neutral comet assay were used to detect DNA double-strand breaks (DSBs). Intracellular levels of reactive oxygen species and NO were detected with fluorescent dyes. Mitochondrial viability was measured with a rhodamine dye. Long-term survival was assessed by clonogenic assay. Exposure to acid (pH 3.5) for > or =15 minutes induced DSBs in all cell lines (P 25 micromol/L) and cell-dependent manner (adenocarcinoma >Barrett's esophagus, P < .05). This occurred preferentially in S-phase cells consistent with stalled replication forks and was blocked with a NO scavenger. NO also induced DSBs in primary Barrett's esophagus cells treated ex vivo. Cells were able to survive when exposed to acid and NO. Both acid and NO have the potential to generate DSBs in the esophagus and via distinct mechanisms.
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: 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: Informa UK Limited
Date: 05-07-2017
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: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3SM50646K
Publisher: eLife Sciences Publications, Ltd
Date: 18-03-2020
DOI: 10.7554/ELIFE.56968
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: 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: eLife Sciences Publications, Ltd
Date: 04-11-2019
DOI: 10.7554/ELIFE.48828
Abstract: Human Tim8a and Tim8b are members of an intermembrane space chaperone network, known as the small TIM family. Mutations in TIMM8A cause a neurodegenerative disease, Mohr-Tranebjærg syndrome (MTS), which is characterised by sensorineural hearing loss, dystonia and blindness. Nothing is known about the function of hTim8a in neuronal cells or how mutation of this protein leads to a neurodegenerative disease. We show that hTim8a is required for the assembly of Complex IV in neurons, which is mediated through a transient interaction with Complex IV assembly factors, in particular the copper chaperone COX17. Complex IV assembly defects resulting from loss of hTim8a leads to oxidative stress and changes to key apoptotic regulators, including cytochrome c, which primes cells for death. Alleviation of oxidative stress with Vitamin E treatment rescues cells from apoptotic vulnerability. We hypothesise that enhanced sensitivity of neuronal cells to apoptosis is the underlying mechanism of MTS.
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: American Society for Clinical Investigation
Date: 12-2010
DOI: 10.1172/JCI43653
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: Elsevier BV
Date: 03-2005
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: Proceedings of the National Academy of Sciences
Date: 13-01-2010
Abstract: The stromal compartment is increasingly recognized to play a role in cancer. However, its role in the transition from preinvasive to invasive disease is unknown. Most gastrointestinal tumors have clearly defined premalignant stages, and Barrett’s esophagus (BE) is an ideal research model. Supervised clustering of gene expression profiles from microdissected stroma identified a gene signature that could distinguish between BE metaplasia, dysplasia, and esophageal adenocarcinoma (EAC). EAC patients overexpressing any of the five genes ( TMEPAI , JMY , TSP1 , FAPα , and BCL6 ) identified from this stromal signature had a significantly poorer outcome. Gene ontology analysis identified a strong inflammatory component in BE disease progression, and key pathways included cytokine–cytokine receptor interactions and TGF-β. Increased protein levels of inflammatory-related genes significantly up-regulated in EAC compared with preinvasive stages were confirmed in the stroma of independent s les, and in vitro assays confirmed functional relevance of these genes. Gene set enrichment analysis of external datasets demonstrated that the stromal signature was also relevant in the preinvasive to invasive transition of the stomach, colon, and pancreas. These data implicate inflammatory pathways in the genesis of gastrointestinal tract cancers, which can affect prognosis.
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: eLife Sciences Publications, Ltd
Date: 26-10-2019
Publisher: Wiley
Date: 08-01-2015
DOI: 10.1002/PATH.4467
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: MDPI AG
Date: 21-06-2021
Abstract: A critical hallmark of cancer cells is their ability to evade programmed apoptotic cell death. Consequently, resistance to anti-cancer therapeutics is a hurdle often observed in the clinic. Ferroptosis, a non-apoptotic form of cell death distinguished by toxic lipid peroxidation and iron accumulation, has garnered substantial attention as an alternative therapeutic strategy to selectively destroy tumours. Although there is a plethora of research outlining the molecular mechanisms of ferroptosis, these findings are yet to be translated into clinical compounds inducing ferroptosis. In this perspective, we elaborate on how ferroptosis can be leveraged in the clinic. We discuss a therapeutic window for compounds inducing ferroptosis, the subset of tumour types that are most sensitive to ferroptosis, conventional therapeutics that induce ferroptosis, and potential strategies for lowering the threshold for ferroptosis.
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: 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 Society for Clinical Investigation
Date: 08-2014
DOI: 10.1172/JCI66603
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 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: EMBO
Date: 14-12-2020
Publisher: Springer Science and Business Media LLC
Date: 2006
DOI: 10.1379/CSC-206.1
Abstract: Heat shock protein 70 (Hsp70) is a well-known inhibitor of apoptotic pathways however, a role for Hsp70 in the modulation of death receptor-mediated apoptosis remains largely unexplored. In this study, the ability of Hsp70 to modulate tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL)-induced apoptosis was examined in SW480 and CCRF-CEM cells. These lines exhibit the characteristics of type I cells (SW480, human colon adenocarcinoma), with no requirement for mitochondrial involvement to exhibit apoptosis following death receptor engagement and type II cells (CCRF-CEM, human leukemic T cell), which do require lification of the signal through the mitochondria. Unexpectedly, expression of Hsp70 in the type II CCRF-CEM cells enhanced the extent of TRAIL-induced apoptosis, but in SW480, Hsp70 had no impact on TRAIL-induced apoptosis. The enhanced TRAIL-induced apoptosis was accompanied by an up-regulation of TRAIL receptors, R1 and R2, at the cell surface as determined by flow cytometry and at the transcriptional level as assessed by real-time polymerase chain reaction (PCR). Increased expression of Hsp70 led to up-regulated expression of p53, and chromatin immunoprecipitation combined with real-time PCR revealed increased binding of p53 to its consensus sequence in the TRAIL-R2 gene. In contrast, expression of Hsp70 in SW480 cells did not increase p53 or TRAIL-R1 or TRAIL-R2 surface expression. This result is in marked contrast to most apoptotic stresses, including TNFalpha and Fas ligand, where Hsp70 has been shown to inhibit apoptosis in type II cells. These findings suggest that in tumors retaining functional p53 and expressing high levels of Hsp70, TRAIL may be an effective therapy.
Publisher: Impact Journals, LLC
Date: 16-11-2016
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: 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: 10.1158/1535-7163.22521237.V1
Abstract: Figure S2 shows APR-246 and PX-12 activity correlate in CTRPv2 and their impact on mutant-p53 thermostability.
Publisher: 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: Wiley
Date: 26-02-2018
DOI: 10.1002/PATH.5041
Abstract: The pathogenesis of oro-oesophaeal squamous cell carcinoma is causally linked to the consumption of alcohol. Beyond the carcinogenic effects of ethanol and its metabolites via DNA damage, the precise mechanisms by which alcohol drives tumourigenesis remain to be fully elucidated. A novel contributor now revealed is aberrant differentiation and proliferation mediated by suppression of PAX9, a key regulator of normal squamous maturation in oro-oesophageal tissues. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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: Oxford University Press (OUP)
Date: 27-06-2010
Abstract: Nitric oxide (NO) has been shown to induce double strand DNA breaks in Barrett's oesophagus (BO) and in other cancers has a role in invasion. The specific aims of this study were to investigate whether NO can induce invasion in cells representative of different stages of Barrett's progression and to determine possible underlying mechanisms. Physiological concentrations of NO that mimic luminal production of NO from dietary sources enhanced invasion in cell lines from high-grade dysplasia (GihTERT) and oesophageal adenocarcinoma (FLO) but not a non-dysplastic Barrett's cell line (QhTERT). Real-time reverse transcription-polymerase chain reaction revealed that NO induced expression of matrix metalloproteinase (MMP)-1, -3, -7, -9 and -10 and tissue inhibitor of metalloproteinase (TIMP)-1, -2 and -3 in these cell lines. Furthermore, ex vivo treatment of Barrett's biopsy s les with NO induced increases in MMP-1 and TIMP-1 expression, suggesting that NO enhances invasion through deregulating MMP and TIMP expression in epithelial cells. In keeping with these findings, microarray analysis and immunohistochemistry performed on biopsy s les showed enhanced expression of MMP-1, -3, -7 and -10 and TIMP-1 in the progression from non-dysplastic BO to adenocarcinoma, although this could not be directly attributed to the effect of NO. Thus, NO may play a role in Barrett's carcinogenesis through deregulating MMP and TIMP expression to enhance invasive potential.
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: Springer Science and Business Media LLC
Date: 03-08-2022
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: Elsevier BV
Date: 05-2010
Publisher: Wiley
Date: 25-05-2006
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: 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: Elsevier BV
Date: 2023
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: eLife Sciences Publications, Ltd
Date: 26-10-2019
Publisher: Springer Science and Business Media LLC
Date: 15-07-2021
DOI: 10.1038/S41419-021-03988-Y
Abstract: Asparaginase depletes extracellular asparagine in the blood and is an important treatment for acute lymphoblastic leukemia (ALL) due to asparagine auxotrophy of ALL blasts. Unfortunately, resistance occurs and has been linked to expression of the enzyme asparagine synthetase (ASNS), which generates asparagine from intracellular sources. Although TP53 is the most frequently mutated gene in cancer overall, TP53 mutations are rare in ALL. However, TP53 mutation is associated with poor therapy response and occurs at higher frequency in relapsed ALL. The mutant p53-reactivating compound APR-246 (Eprenetapopt/PRIMA-1Met) is currently being tested in phase II and III clinical trials in several hematological malignancies with mutant TP53 . Here we present CEllular Thermal Shift Assay (CETSA) data indicating that ASNS is a direct or indirect target of APR-246 via the active product methylene quinuclidinone (MQ). Furthermore, combination treatment with asparaginase and APR-246 resulted in synergistic growth suppression in ALL cell lines. Our results thus suggest a potential novel treatment strategy for ALL.
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.
Publisher: MDPI AG
Date: 16-08-2022
Abstract: Metastatic prostate cancer is a lethal disease in patients incapable of responding to therapeutic interventions. Invasive prostate cancer spread is caused by failure of the normal anti-cancer defense systems that are controlled by the tumour suppressor protein, p53. Upon mutation, p53 malfunctions. Therapeutic strategies to directly re-empower the growth-restrictive capacities of p53 in cancers have largely been unsuccessful, frequently because of a failure to discriminate responses in diseased and healthy tissues. Our studies sought alternative prostate cancer drivers, intending to uncover new treatment targets. We discovered the oncogenic potency of MDM4 in prostate cancer cells, both in the presence and absence of p53 and also its mutation. We uncovered that sustained depletion of MDM4 is growth inhibitory in prostate cancer cells, involving either apoptosis or senescence, depending on the cell and genetic context. We identified that the potency of MDM4 targeting could be potentiated in prostate cancers with mutant p53 through the addition of a first-in-class small molecule drug that was selected as a p53 reactivator and has the capacity to elevate oxidative stress in cancer cells to drive their death.
Publisher: Springer Science and Business Media LLC
Date: 12-09-2023
Publisher: MDPI AG
Date: 24-05-2021
DOI: 10.3390/IJMS22115547
Abstract: TP53 gene mutations occur in 70% of oesophageal adenocarcinomas (OACs). Given the central role of p53 in controlling cellular response to therapy we investigated the role of mutant (mut-) p53 and SLC7A11 in a CRISPR-mediated JH-EsoAd1 TP53 knockout model. Response to 2 Gy irradiation, cisplatin, 5-FU, 4-hydroxytamoxifen, and endoxifen was assessed, followed by a TaqMan OpenArray qPCR screening for differences in miRNA expression. Knockout of mut-p53 resulted in increased chemo- and radioresistance (2 Gy survival fraction: 38% vs. 56%, p 0.0001) and in altered miRNA expression levels. Target mRNA pathways analyses indicated several potential mechanisms of treatment resistance. SLC7A11 knockdown restored radiosensitivity (2 Gy SF: 46% vs. 73% p = 0.0239), possibly via enhanced sensitivity to oxidative stress. Pathway analysis of the mRNA targets of differentially expressed miRNAs indicated potential involvement in several pathways associated with apoptosis, ribosomes, and p53 signaling pathways. The data suggest that mut-p53 in JH-EsoAd1, despite being classified as non-functional, has some function related to radio- and chemoresistance. The results also highlight the important role of SLC7A11 in cancer metabolism and redox balance and the influence of p53 on these processes. Inhibition of the SLC7A11-glutathione axis may represent a promising approach to overcome resistance associated with mut-p53.
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 2017
End Date: 2020
Funder: National Health and Medical Research Council
View Funded ActivityStart Date: 2010
End Date: 2012
Funder: National Health and Medical Research Council
View Funded ActivityStart Date: 2008
End Date: 2010
Funder: Australian Research Council
View Funded ActivityStart Date: 2010
End Date: 2012
Funder: Department of Health, Victorian State Government
View Funded ActivityStart Date: 2010
End Date: 2012
Funder: National Health and Medical Research Council
View Funded ActivityStart Date: 2019
End Date: 2020
Funder: Peter MacCallum Cancer Foundation
View Funded ActivityStart Date: 2019
End Date: 2021
Funder: Cancer Council Victoria
View Funded Activity