ORCID Profile
0000-0001-5954-7105
Current Organisation
Flinders Medical Centre
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Publisher: Springer Science and Business Media LLC
Date: 22-07-2014
Publisher: Springer Science and Business Media LLC
Date: 19-12-2011
DOI: 10.1007/S00418-010-0772-0
Abstract: Damage to sensory neurons induces neural repair, regrowth and hyperexcitability. The regulation of such responses to injury must be organized in some way by the neurons. Regulation can occur at the post-transcriptional level via microRNAs (miRNAs). miRNAs are small non-coding RNAs that influence the stability or translation of mRNAs and thereby regulate gene expression. Although nociceptive neurons show transcriptional and post-transcriptional regulatory mechanisms at many levels, miRNAs have not yet been systematically investigated in these neurons. Based on our preliminary array data we investigated the presence of miR-1 in dorsal root ganglion (DRG) neurons of mice and humans. We detected miR-1 in total RNA from human and mouse DRG and localised miR-1 in human and murine sensory neurons in situ. In Situ Hybridization detected miR-1 expression by nearly all DRG neurons. In vitro studies of enriched sensory neuron subpopulations from mouse DRG showed higher miR-1 expression levels in I-B4 negative neurons compared with I-B4 positive cells. Culturing of primary sensory neurons reduced the relative miR-1 expression levels independent of the presence or absence of laminin on the culture substrate. Transfection with a miR-1 mimic induced a massive increase in neuronal miR-1 associated with attenuated neurite outgrowth. This first description of miR-1 in sensory neurons including nociceptors suggests that miR-1 has a role in modulating neurite outgrowth.
Publisher: Frontiers Media SA
Date: 05-2019
Publisher: Spandidos Publications
Date: 04-07-2011
DOI: 10.3892/OR.2011.1381
Abstract: Neoadjuvant chemotherapy is often used in the treatment of advanced esophageal cancer. In this study, we determined the impact of chemotherapy on microRNA (miRNA) expression in esophageal cancer cells, and whether identified changes might have biological relevance. Two esophageal carcinoma cell lines (one adenocarcinoma and one squamous cell carcinoma) were treated with cisplatin or 5-fluorouracil for 24 or 72 h. RNA was extracted from cells following 24-h treatment, and used for microarray studies. Promising miRNA candidates were selected for RT-PCR validation. Target prediction using TargetScan, combined with bioinformatic analysis (Ingenuity Pathway Analysis, IPA), was performed to evaluate the implications of the altered miRNA expression. Thirteen miRNAs (miR-199a-5p, miR-302f, miR-320a, miR-342-3p, miR-425, miR-455-3p, miR-486-3p, miR-519c-5p, miR-548d-5p, miR-617, miR-758, miR-766, miR-1286) were deregulated after 24- and/or 72-h treatment in both cell lines, and most miRNAs presented similar expression changes after short- or long-term exposure. IPA revealed that the major networks which incorporate the predicted targets, include functions such as 'Cell death', 'Cell cycle', 'Cellular growth and proliferation', 'DNA replication, recombination, and repair' and 'Drug metabolism'. Cisplatin or 5-fluorouracil alter miRNA expression in esophageal cancer cells. IPA suggests that these miRNAs may target molecular pathways involved in cell survival after chemotherapy.
Publisher: Springer Science and Business Media LLC
Date: 14-07-2011
DOI: 10.1245/S10434-010-1213-Y
Abstract: Prognostic and staging information for esophageal cancer impacts clinical decision making. miRNAs, a newly discovered class of biomarkers and their expression might add additional information relevant to this. In this study we evaluated the expression of selected miRNAs and their relationship to tumor stage and survival in patients with locally advanced tumors following esophagectomy. A total of 43 in iduals undergoing esophagectomy (without neoadjuvant therapy) for locally advanced but not metastatic (pT2/3 pN0/1) disease (22 adenocarcinoma [EAC], 21 squamous cell carcinoma [SCC]) were included in this study. Perioperative clinical and survival data were collected and managed on a database. The expression of miR-21, miR-106a, miR-148a, miR-205 in formalin-fixed paraffin-embedded specimens was evaluated by TaqMan qPCR assays. Expression was compared with clinicopathological features of the cancers and outcome. In EAC, miR-148a expression levels were inversely associated with cancer differentiation. miR-21 expression levels were higher in SCC if distant lymph node metastases were present. miR-148a levels were lower when EAC was more proximally located, and miR-21 levels were lower when SCC was more proximal. miR-106a and miR-148a were lower in patients with SCC who developed recurrent disease or had a tumor-related death. In patients with locally advanced esophageal squamous cell carcinoma, but not adenocarcinoma, alterations in the expression of miR-21 correlate with tumor location and lymph node status. Furthermore, miR-106a and miR-148a expression correlates with disease recurrence and tumor-related mortality. miRNA markers might inform the initial assessment of these patients, and predict those at higher risk of postsurgical recurrence.
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: Oxford University Press (OUP)
Date: 22-03-2011
DOI: 10.1093/NAR/GKR110
Publisher: Springer Science and Business Media LLC
Date: 06-2018
DOI: 10.1038/S41540-018-0056-1
Abstract: Recent advances in high-throughput technologies have provided an unprecedented opportunity to identify molecular markers of disease processes. This plethora of complex-omics data has simultaneously complicated the problem of extracting meaningful molecular signatures and opened up new opportunities for more sophisticated integrative and holistic approaches. In this era, effective integration of data-driven and knowledge-based approaches for biomarker identification has been recognised as key to improving the identification of high-performance biomarkers, and necessary for translational applications. Here, we have evaluated the role of circulating microRNA as a means of predicting the prognosis of patients with colorectal cancer, which is the second leading cause of cancer-related death worldwide. We have developed a multi-objective optimisation method that effectively integrates a data-driven approach with the knowledge obtained from the microRNA-mediated regulatory network to identify robust plasma microRNA signatures which are reliable in terms of predictive power as well as functional relevance. The proposed multi-objective framework has the capacity to adjust for conflicting biomarker objectives and to incorporate heterogeneous information facilitating systems approaches to biomarker discovery. We have found a prognostic signature of colorectal cancer comprising 11 circulating microRNAs. The identified signature predicts the patients’ survival outcome and targets pathways underlying colorectal cancer progression. The altered expression of the identified microRNAs was confirmed in an independent public data set of plasma s les of patients in early stage vs advanced colorectal cancer. Furthermore, the generality of the proposed method was demonstrated across three publicly available miRNA data sets associated with biomarker studies in other diseases.
Publisher: Oxford University Press (OUP)
Date: 18-03-2010
DOI: 10.1002/BJS.7000
Abstract: The genetic changes that drive metaplastic progression from squamous oesophageal mucosa toward intestinal metaplasia and adenocarcinoma are unclear. The aberrant expression of microRNAs (miRNAs) is involved in the development of cancer. This study examined whether miRNAs play a role in the development of oesophageal adenocarcinoma. RNA was extracted from mucosa of normal oesophageal squamous epithelium, normal gastric epithelium, Barrett's oesophagus with intestinal metaplasia and oesophageal adenocarcinoma obtained from 16 in iduals. Expression profiles of 377 human miRNAs were determined by microarray analysis and selected miRNAs were analysed further using real-time reverse transcription–polymerase chain reaction (RT–PCR) in tissues from 32 in iduals. Microarray analyses identified 44 miRNAs likely to have altered expression between various mucosal s les. Of these, miR-21, miR-143, miR-145, miR-194, miR-203, miR-205 and miR-215 were chosen for validation by real-time RT-PCR. Tissue-specific expression profiles were observed, with miR-21, miR-143, miR-145, miR-194 and miR-215 significantly upregulated in columnar tissues compared with normal squamous epithelium. Expression of miR-143, miR-145 and miR-215 was lower in oesophageal adenocarcinoma than in Barrett's oesophagus. Levels of miR-203 and miR-205 were high in normal squamous epithelium and low in columnar epithelia. MiR-205 levels were lower in gastric epithelium than in both Barrett's oesophagus and adenocarcinoma. Expression of miRNA might define disease states in oesophageal epithelium. Dysregulation of specific miRNAs could contribute to metaplastic and neoplastic processes in the oesophageal mucosa.
Publisher: American Society of Hematology
Date: 30-09-2010
DOI: 10.1182/BLOOD-2009-12-256297
Abstract: The specification of arterial, venous, and lymphatic endothelial cell fate is critical during vascular development. Although the homeobox transcription factor, Prox1, is crucial for the specification and maintenance of lymphatic endothelial cell identity, little is known regarding the mechanisms that regulate Prox1 expression. Here we demonstrate that miR-181a binds the 3′ untranslated region of Prox1, resulting in translational inhibition and transcript degradation. Increased miR-181a activity in primary embryonic lymphatic endothelial cells resulted in substantially reduced levels of Prox1 mRNA and protein and reprogramming of lymphatic endothelial cells toward a blood vascular phenotype. Conversely, treatment of primary embryonic blood vascular endothelial cells with miR-181a antagomir resulted in increased Prox1 mRNA levels. miR-181a expression is significantly higher in embryonic blood vascular endothelial cells compared with lymphatic endothelial cells, suggesting that miR-181 activity could be an important mechanism by which Prox1 expression is silenced in the blood vasculature during development. Our work is the first ex le of a microRNA that targets Prox1 and has implications for the control of Prox1 expression during vascular development and neo-lymphangiogenesis.
Publisher: Wiley
Date: 14-04-2016
DOI: 10.1111/JFD.12458
Publisher: Elsevier BV
Date: 05-2019
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 07-2006
Publisher: MDPI AG
Date: 07-02-2023
DOI: 10.3390/IJMS24043304
Abstract: The interaction between leukocytes and cytokine-activated retinal endothelium is an initiating step in non-infectious uveitis involving the posterior eye, mediated by cell adhesion molecules. However, because cell adhesion molecules are required for immune surveillance, therapeutic interventions would ideally be employed indirectly. Using 28 primary human retinal endothelial cell isolates, this study sought to identify transcription factor targets for reducing levels of the key retinal endothelial cell adhesion molecule, intercellular adhesion molecule (ICAM)-1, and limiting leukocyte binding to the retinal endothelium. Five candidate transcription factors—C2CD4B, EGR3, FOSB, IRF1, and JUNB—were identified by differential expression analysis of a transcriptome generated from IL-1β- or TNF-α-stimulated human retinal endothelial cells, interpreted in the context of the published literature. Further filtering involved molecular studies: of the five candidates, C2CD4B and IRF1 consistently demonstrated extended induction in IL-1β- or TNF-α-activated retinal endothelial cells and demonstrated a significant decrease in both ICAM-1 transcript and ICAM-1 membrane-bound protein expression by cytokine-activated retinal endothelial cells following treatment with small interfering RNA. RNA interference of C2CD4B or IRF1 significantly reduced leukocyte binding in a majority of human retinal endothelial cell isolates stimulated by IL-1β or TNF-α. Our observations suggest that the transcription factors C2CD4B and IRF1 may be potential drug targets for limiting leukocyte–retinal endothelial cell interactions in non-infectious uveitis involving the posterior eye.
Publisher: Springer Science and Business Media LLC
Date: 02-05-2008
DOI: 10.1007/S11605-008-0522-Y
Abstract: Changes in the expression of mucin genes in the esophageal mucosa associated with uncomplicated gastro-esophageal reflux disease have not been evaluated even though such changes could be associated with reflux-induced mucosal damage. We therefore sought to identify reflux-induced changes in mucin gene expression using a cell line and biopsies from the esophageal mucosa in patients with and without reflux. MUC-1, MUC-3, MUC-4, and MUC-5AC gene expressions were investigated in the HET-1A cell line following exposure to acid (pH 4) and/or bile (120 muM of a bile salt milieu), and in esophageal mucosal biopsies from controls, subjects with non-erosive gastro-esophageal reflux, and subjects with reflux associated with ulcerative esophagitis (erosive). The mucosal biopsies were also evaluated for IL-6 mRNA expression (inflammatory marker) and CK-14 mRNA expression (mucosal basal cell layer marker). Gene expression was determined using real-time reverse transcriptase-polymerase chain reaction analysis. In the cell line studies, there were differences in mRNA levels for all of the evaluated mucins following treatment with either acid or the acid and bile combination. In the studies which evaluated tissue specimens, IL-6 and CK-14 mRNA levels increased according to degree of reflux pathology. The expression of MUC-1 and MUC-4 in mucosa from patients with erosive reflux was lower than in subjects without reflux and in patients with non-erosive reflux, whereas the expression of MUC-3 and MUC-5AC was increased (although these differences did not reach significance at p < 0.05). When mRNA expression data for tissue s les from all groups were combined, significant correlations were identified between IL-6 vs. CK-14 and IL-6 vs. MUC-3, MUC-3 vs. CK-14 and MUC-3 vs. MUC-5AC, and for MUC-1 vs. MUC-5AC. The correlation between IL-6 and CK-14 was also significant within the control and non-erosive reflux groups. The correlation between IL-6 and MUC-3 was significant within the control and erosive reflux groups, and the correlation between MUC-1 and MUC-5AC was significant within the erosive reflux group. The results of this study suggest that the profile of mucin expression in the esophageal mucosa is influenced by the pH and composition of the gastro-esophageal reflux. Further work should explore the response of these genes to acid and bile reflux, and their role in the etiology of mucosal damage in gastro-esophageal reflux.
Publisher: Springer Science and Business Media LLC
Date: 19-01-2011
DOI: 10.1007/S11605-011-1418-9
Abstract: Response to chemotherapy varies widely in patients with advanced oesophageal cancer. We investigated the impact of manipulating certain microRNAs on response to cisplatin and 5-fluorouracil (5-FU) in oesophageal cancer cells. Cisplatin-/5-fluorouracil-resistant oesophageal squamous cell carcinoma (SCC) and adenocarcinoma (EAC) cell lines were established, and the impact of ectopic upregulation of miR-106a and miR-148a on response to both drugs was assessed. The impact of miR-106a-upregulation was inconsistent. Upregulation was followed by reduced sensitivity to cisplatin in chemotherapy-sensitive EAC cells (cell survival, +8.7 ± 0.8% p = 0.003) and an improved response to 5-FU in cisplatin-resistant EAC cells (cell survival, -6.4 ± 2.5% p = 0.011). MiR-148a upregulation significantly increased sensitivity to chemotherapy in seven out of ten cell lines, represented by a decrease in cell viability of 22.6 ± 7.9% to 50.5 ± 10.6% after cisplatin (p ≤ 0.014) and 6.0 ± 0.8% to 15.0 ± 4.1% after 5-FU treatment (p ≤ 0.012). The only cell lines in which miR-148a upregulation had no effect were cisplatin-resistant EAC exposed to cisplatin and 5-FU-sensitive and 5-FU-resistant SCC cells exposed to 5-FU. MiR-148a sensitized chemotherapy-sensitive oesophageal cancer cell lines to cisplatin and, to a lesser extent, to 5-flurouracil and attenuated resistance in chemotherapy-resistant variants. Further experimental and clinical studies to investigate the exact mechanisms involved are warranted.
Publisher: Wiley
Date: 06-2007
DOI: 10.1111/J.1365-2982.2007.00940.X
Abstract: Gallbladder inflammation is a common and painful disease. Inducible nitric oxide synthase (iNOS) plays a major role in inflammatory diseases, and iNOS inhibitors are being developed as therapeutic agents. Reports are inconsistent regarding iNOS expression in normal gallbladder. The aim of this study was to determine the effect of iNOS inhibition on spontaneous gallbladder motility. mRNA extracted from normal possum gallbladders was analysed by PCR. Gallbladder contractility was evaluated using a highly selective iNOS inhibitor AR-C102222AA (AR-C) in in vitro muscle strips (0.1-10 000 microm) and in vivo (0.1-30 micromol kg(-1)) experiments. Gene expression analysis revealed the presence of iNOS mRNA in normal gallbladder (n = 3). In vitro, AR-C (0.1-1000 micromol L(-1)) produced a concentration-dependent increase in spontaneous gallbladder contractile activity and basal tension (P < 0.05 n = 6). The maximum effect was a 1.8-fold increase in activity and 2.1-fold increase in basal tension. Pretreatment of muscle strips with tetrodotoxin (1 micromol L(-1)) did not block the AR-C-induced response (n = 5). In vivo, AR-C (30 micromol kg(-1), i.v.) increased gallbladder contraction frequency (P < 0.05 n = 8). These data suggest that iNOS is continually expressed in the normal gallbladder, which presumably releases low levels of nitric oxide and in turn may modulate spontaneous gallbladder motility. AR-C may be a beneficial treatment for patients suffering from acute cholecystitis.
Publisher: Springer Science and Business Media LLC
Date: 10-2019
DOI: 10.1186/S13104-019-4671-8
Abstract: Survivors of Ebola virus disease (EVD) are at risk of developing blinding intraocular inflammation—or uveitis—which is associated with retinal pigment epithelial (RPE) scarring and persistence of live Zaire ebolavirus (EBOV) within the eye. As part of a large research project aimed at defining the human RPE cell response to being infected with EBOV, this work focused on the microRNAs (miRNAs) associated with the infection. Using RNA-sequencing, we detected 13 highly induced and 2 highly repressed human miRNAs in human ARPE-19 RPE cells infected with EBOV, including hsa-miR-1307-5p, hsa-miR-29b-3p and hsa-miR-33a-5p (up-regulated), and hsa-miR-3074-3p and hsa-miR-27b-5p (down-regulated). EBOV-miR-1-5p was also found in infected RPE cells. Through computational identification of putative miRNA targets, we predicted a broad range of regulatory activities, including effects on innate and adaptive immune responses, cellular metabolism, cell cycle progression, apoptosis and autophagy. The most highly-connected molecule in the miR-target network was leucine-rich repeat kinase 2, which is involved in neuroinflammation and lysosomal processing. Our findings should stimulate new studies on the impact of miRNA changes in EBOV-infected RPE cells to further understanding of intraocular viral persistence and the pathogenesis of uveitis in EVD survivors.
Publisher: Wiley
Date: 27-08-2010
DOI: 10.1111/J.1440-1797.2010.01363.X
Abstract: MicroRNAs (miRNAs) are short non-coding RNAs that modulate physiological and pathological processes by inhibiting target gene expression via blockade of protein translation or by inducing mRNA degradation. These miRNAs potentially regulate the expression of thousands of proteins. As a result, miRNAs have emerged rapidly as a major new area of biomedical research with relevance to kidney disease. MiRNA expression has been shown to differ between the kidney and other organs as well as between different kidney regions. Furthermore, miRNAs have been found to be functionally important in models of podocyte development, diabetic nephropathy and polycystic kidney disease. Of particular interest, podocyte-specific deletion of Dicer, a key enzyme in the biogenesis of miRNA, results in proteinuria and severe renal impairment in mice. One miRNA (miR-192) can also act as an effector of transforming growth factor-β activity in the high-glucose environment of diabetic nephropathy. Differential expression of miRNAs has been reported in kidney allograft rejection. It is anticipated that future studies involving miRNAs will generate new insights into the complex pathophysiology underlying various kidney diseases, generate diagnostic biomarkers and might be of value as therapeutic targets for progressive kidney diseases. The purpose of this review is to highlight key miRNA developments in kidney diseases and how this might influence the diagnosis and management of patients with kidney disease in the future.
Publisher: American Association for Cancer Research (AACR)
Date: 12-2017
DOI: 10.1158/1535-7163.MCT-17-0074
Abstract: We investigated the potential of combining the hypoglycemic drug metformin (MET) and the antiepileptic drug valproic acid (VPA), which act via different biochemical pathways, to provide enhanced antitumor responses in prostate cancer. Prostate cancer cell lines (LNCaP and PC-3), normal prostate epithelial cells (PrEC), and patient-derived prostate tumor explants were treated with MET and/or VPA. Proliferation and apoptosis were assessed. The role of p53 in response to MET + VPA was assessed in cell lines using RNAi in LNCaP (p53+) and ectopic expression of p53 in PC-3 (p53−). The role of the androgen receptor (AR) was investigated using the AR antagonist enzalutamide. The combination of MET and VPA synergistically inhibited proliferation in LNCaP and PC-3, with no significant effect in PrEC. LNCaP, but not PC-3, demonstrated synergistic intrinsic apoptosis in response to MET + VPA. Knockdown of p53 in LNCaP (p53+, AR+) reduced the synergistic apoptotic response as did inhibition of AR. Ectopic expression of p53 in PC-3 (p53−, AR−) increased apoptosis in response to MET + VPA. In patient-derived prostate tumor explants, MET + VPA also induced a significant decrease in proliferation and an increase in apoptosis in tumor cells. In conclusion, we demonstrate that MET + VPA can synergistically kill more prostate cancer cells than either drug alone. The response is dependent on the presence of p53 and AR signaling, which have critical roles in prostate carcinogenesis. Further in vivo/ex vivo preclinical studies are required to determine the relative efficacy of MET + VPA as a potential treatment for prostate cancer. Mol Cancer Ther 16(12) 2689–700. ©2017 AACR.
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 14-07-2017
DOI: 10.1167/TVST.6.4.12
Publisher: Baishideng Publishing Group Inc.
Date: 2014
Publisher: Springer Science and Business Media LLC
Date: 21-10-2010
Abstract: The commonest histological type of renal cancer, clear cell renal cell carcinoma (cc RCC), is associated with genetic and epigenetic changes in the von Hippel-Lindau (VHL) tumour suppressor. VHL inactivation leads to induction of hypoxia-inducible factors (HIFs) and a hypoxic pattern of gene expression. Differential levels of specific microRNAs (miRNAs) are observed in several tumours when compared to normal tissue. Given the central role of VHL in renal cancer formation, we examined the VHL-dependent regulation of miRNAs in renal cancer. VHL-dependent miRNA expression in cc RCC was determined by microarray analysis of renal cell line RCC4 with mutated VHL (RCC4-VHL) and reintroduced wild-type VHL (RCC4 + VHL). Five miRNAs highly upregulated in RCC4 + VHL and five miRNAs highly downregulated in RCC4 + VHL were studied further, in addition to miR-210, which is regulated by the HIF-VHL system. miRNA expression was also measured in 31 cc RCC tumours compared to adjacent normal tissue. A significant increase in miR-210, miR-155 and miR-21 expression was observed in the tumour tissue. miR-210 levels also showed a correlation with a HIF-regulated mRNA, carbonic anhydrase IX (CAIX), and with VHL mutation or promoter methylation. An inverse correlation was observed between miR-210 expression and patient survival, and a putative target of miR-210, iron-sulfur cluster assembly protein (ISCU1/2), shows reciprocal levels of mRNA expression in the tumours. We have identified VHL-regulated miRNAs and found that for some the regulation is HIF-dependent and for others it is HIF-independent. This pattern of regulation was also seen in renal cancer tissue for several of these miRNAs (miR-210, miR-155, let-7i and members of the miR-17-92 cluster) when compared with normal tissue. miR-210 showed marked increases in expression in renal cancer and levels correlated with patient survival. The inverse correlation between miR-210 levels and ISCU1/2 provides support for the hypothesis that ISCU1/2 is a target of miR-210 and that it may contribute to the anaerobic respiration seen in renal (and other) tumours. See Commentary: 741-7015/8/65
Publisher: Oxford University Press (OUP)
Date: 1989
Abstract: Many strains of E. coli K12 restrict DNA containing cytosine methylation such as that present in plant and animal genomes. Such restriction can severely inhibit the efficiency of cloning genomic DNAs. We have quantitatively evaluated a total of 39 E. coli strains for their tolerance to cytosine methylation in phage and plasmid cloning systems. Quantitative estimations of relative tolerance to methylation for these strains are presented, together with the evaluation of the most promising strains in practical recombinant cloning situations. Host strains are recommended for different recombinant cloning requirements. These data also provide a rational basis for future construction of 'ideal' hosts combining optimal methylation tolerance with additional advantageous mutations.
Publisher: Springer Science and Business Media LLC
Date: 04-02-2009
DOI: 10.1007/S11605-009-0799-5
Abstract: Ablation of Barrett's esophagus using Argon plasma coagulation (APC) is usually followed by the formation of a neosquamous epithelium. Investigating simple columnar or stratified squamous epithelium associated cytokeratin and microRNA (miRNA) expression in neo-squamous epithelium could help determine the identity and stability of the neosquamous epithelium. Nine patients underwent ablation of Barrett's esophagus with APC. Biopsies were collected from Barrett's esophagus mucosa and proximal normal squamous epithelium before ablation, and from neosquamous and normal squamous epithelium after ablation. Additional esophageal mucosal biopsies from ten nonrefluxing subjects were used as a reference. RNA was extracted and real-time polymerase chain reaction was used to measure the expression of the cytokeratins CK-8 and CK-14 and the microRNAs miR-143 and miR-205. CK-8 and miR-143 expression were significantly higher in Barrett's esophagus mucosa, compared to neosquamous and normal squamous epithelium before and after APC, whereas miRNA-205 and CK-14 expression was significantly lower in Barrett's esophagus mucosa compared to all categories of squamous mucosa. The expression of CK-8, CK-14, miR-205, and miR-143 was similar between neosquamous epithelium compared to normal squamous epithelium in patients with Barrett's esophagus. Only miR-143 expression was significantly higher in neosquamous and normal squamous epithelium before and after APC compared to normal squamous epithelium from control subjects (p < 0.004). The expression levels of cytokeratins and miRNAs studied in post-ablation neosquamous epithelium and normal squamous epithelium in patients with Barrett's esophagus are similar. In patients with Barrett's esophagus, miR-143 expression is still elevated in both neosquamous mucosa, and the squamous mucosa above the metaplastic segment, suggesting that this mucosa may not be normal i.e., it is different to that seen in subjects without Barrett's esophagus. miR-143 could promote a Barrett's epithelium gene expression pattern, and this could have a role in development of Barrett's esophagus.
Publisher: Oxford University Press (OUP)
Date: 02-09-2011
DOI: 10.1093/NDT/GFR485
Abstract: MicroRNAs (miRNAs) are important regulators of gene expression, which have roles in renal development and disease. They exist in biological fluids including blood and urine and may have signalling roles and potential as disease biomarkers. We measured the levels of miRNAs in patients with different stages of chronic kidney failure including those receiving maintenance haemodialysis treatment. In patients with severe chronic renal failure, circulating levels of total and specific miRNAs are reduced in comparison to patients with mild renal impairment or normal renal function. A strong correlation exists between detected circulating miRNAs and estimated glomerular filtration rate, and less strong correlations with other features of chronic kidney disease, such as anaemia and hyperparathyroidism. These findings have important implications for the use of circulating miRNAs as biomarkers in in iduals with renal impairment and for the pathogenesis of uraemia.
Publisher: Oxford University Press (OUP)
Date: 12-03-2009
DOI: 10.1002/STEM.63
Abstract: This study characterized the contribution of bone marrow-derived cells to human neoplasia and the perineoplastic stroma. The Australasian Bone Marrow Transplant Recipient Registry was used to identify solid organ neoplasia that developed in female recipients of male allogeneic stem cell transplants. Eighteen suitable cases were identified including several skin cancers, two gastric cancers, and one rectal adenoma. Light microscopy, fluorescence and chromogenic in situ hybridization, and immunohistochemistry were performed to determine the nature and origin of the neoplastic and stromal cells. In contrast to recent reports, donor-derived neoplastic cells were not detected. Bone marrow-derived neoplasia-associated myofibroblasts, however, were identified in the rectal adenoma and in a gastric cancer. Bone marrow-derived cells can generate myofibroblasts in the setting of human gastrointestinal neoplasia. Disclosure of potential conflicts of interest is found at the end of this article.
Publisher: Oxford University Press (OUP)
Date: 2007
DOI: 10.1002/BJS.5673
Abstract: MicroRNAs (miRNAs) are small sequences of RNA, 21 to 22 nucleotides long, that have been discovered recently. They are produced from areas of the human genome that were previously thought to have no function. These sequences now appear to be important in the regulation of many fundamental processes. Evidence has recently emerged that deregulated miRNA activity is associated with human cancers. The English literature was searched using PubMed for publications relevant to miRNAs and cancer. Relevant references from identified publications were also sourced. These publications were reviewed to identify existing evidence for the role of miRNAs in cancer. miRNAs inhibit the translation of mRNA from many target genes involved in cancer development. This leads to changes in the levels of protein encoded by these target genes and drives the development of cancer. The genes that produce miRNAs are frequently located in regions of the genome that are either lost, or lified, in cancer cells. Determination of the miRNA expression profile in cancer tissues should lead to a better understanding of the genetic pathways involved in tumour development.
Publisher: Wiley
Date: 05-02-2013
DOI: 10.1002/MC.21879
Abstract: Diet-derived butyrate, a histone deacetylase inhibitor (HDI), decreases proliferation and increases apoptosis in colorectal cancer (CRC) cells via epigenetic changes in gene expression. Other HDIs such as suberoylanilide hydroxamic acid (SAHA) and trichostatin A (TSA) have similar effects. This study examined the role of microRNAs (miRNAs) in mediating the chemo-protective effects of HDIs, and explored functions of the oncogenic miR-17-92 cluster. The dysregulated miRNA expression observed in HT29 and HCT116 CRC cells could be epigenetically altered by butyrate, SAHA and TSA. These HDIs decreased expression of miR-17-92 cluster miRNAs (P < 0.05), with a corresponding increase in miR-17-92 target genes, including PTEN, BCL2L11, and CDKN1A (P < 0.05). The decrease in miR-17-92 expression may be partly responsible for the anti-proliferative effects of HDIs, with introduction of miR-17-92 cluster miRNA mimics reversing this effect and decreasing levels of PTEN, BCL2L11, and CDKN1A (P < 0.05). The growth effects of HDIs may be mediated by changes in miRNA activity, with down-regulation of the miR-17-92 cluster a plausible mechanism to explain some of the chemo-protective effects of HDIs. Of the miR-17-92 cluster miRNAs, miR-19a and miR-19b were primarily responsible for promoting proliferation, while miR-18a acted in opposition to other cluster members to decrease growth. NEDD9 and CDK19 were identified as novel miR-18a targets and were shown to be pro-proliferative genes, with RNA interference of their transcripts decreasing proliferation in CRC cells. This is the first study to identify competing roles for miR-17-92 cluster members, in the context of HDI-induced changes in CRC cells.
Publisher: Public Library of Science (PLoS)
Date: 07-11-2014
Publisher: Elsevier BV
Date: 05-2014
DOI: 10.1111/AJT.12694
Abstract: BK viral infection is an important cause of renal transplant dysfunction and failure. Current strategies utilize surveillance for infection with DNA polymerase chain reaction assays and modulation of immunosuppression. Many viruses including polyomaviruses encode microRNAs (miRNAs). We have detected BK virus (BKV) encoded miRNAs in the blood of infected renal transplant recipients, and see a strong correlation between BKV encoded miRNA and BKV DNA in blood and a relationship between levels of bkv-miR-B1-5p and the presence of biopsy-proven BK viral nephropathy. Further research is needed to determine whether the detection of this and other virally encoded miRNAs may be useful in the diagnosis of active viral replication.
Publisher: Wiley
Date: 25-08-2015
DOI: 10.1002/DDR.21268
Abstract: Chromatin-modifying drugs, such as histone deacetylase inhibitors (HDACi), have shown potential as cancer therapeutics, either alone or in combination with other therapies. HDACi have the ability to reverse aberrant epigenetic modifications associated with cancer, namely dysregulated histone acetylation. There are currently three FDA approved HDACi vorinostat, romidepsin, and panobinostat. Epigenetic modifications can regulate the expression of protein coding genes, and in addition can alter expression of microRNA (miRNA) genes. Many miRNAs play key roles in cell proliferation and apoptosis, and are commonly dysregulated in cancer states. A number of in vitro and in vivo studies have demonstrated the ability of chromatin-modifying drugs to alter miRNA expression, which may provide the basis for further investigation of miRNAs as therapeutic targets or as biomarkers of drug response. This review summarises findings from studies investigating the effects of HDACi on miRNA expression, as well as key clinical trials involving HDACi. Understanding how chromatin-modifying drugs epigenetically modulate miRNA genes provides further insight into the cellular mechanisms that deliver therapeutic responses, and may assist in refining treatment strategies.
Publisher: Elsevier BV
Date: 09-2015
Publisher: MDPI AG
Date: 09-09-2022
Abstract: The long noncoding RNA NEAT1 is known to be heavily dysregulated in many cancers. A single exon gene produces two isoforms, NEAT1_1 and NEAT1_2, through alternative 3′-end processing. As the longer isoform, NEAT1_2 is an essential scaffold for nuclear paraspeckle formation. It was previously thought that the short NEAT1_1 isoform only exists to keep the NEAT1 locus active for rapid paraspeckle formation. However, a recent glycolysis-enhancing function for NEAT1_1, contributing to cancer cell proliferation and the Warburg effect, has been demonstrated. Previous studies have mainly focused on quantifying total NEAT1 and NEAT1_2 expression levels. However, in light of the NEAT1_1 role in cancer cell metabolism, the contribution from specific NEAT1 isoforms is no longer clear. Here, the roles of NEAT1_1 and NEAT1_2 in metabolism and cancer progression are discussed.
Publisher: Springer New York
Date: 10-12-2017
DOI: 10.1007/978-1-4939-6728-5_3
Abstract: Due to their size, small extracellular vesicles such as exosomes have been difficult to identify and to quantify. As the roles that exosomes play in intercellular signalling become clearer, so does their potential utility as both diagnostic biomarkers for disease and as therapeutic vectors. Accurate assessment of exosomes, both their number and their cargo, is important for continued advancement in the field of vesicle research. To that end, several technologies, including nanoparticle tracking analysis, have been developed to define the physical characteristics of vesicle preparations and determine their concentration. This chapter describes a method for identifying the size and concentration of a subpopulation of vesicles in biological s les, using nanoparticle tracking analysis. Characterization of distinct exosomes is enabled by specific marker antibodies, coupled to fluorescent quantum dots.
Publisher: Springer Science and Business Media LLC
Date: 12-2009
Publisher: MDPI AG
Date: 24-11-0005
DOI: 10.3390/IJMS21238898
Abstract: Many patients with Oesophageal Adenocarcinoma (OAC) do not benefit from chemoradiotherapy treatment due to therapy resistance. To better understand the mechanisms involved in resistance and to find potential biomarkers, we investigated the association of microRNAs, which regulate gene expression, with the response to in idual treatments, focusing on radiation. Intrinsic radiation resistance and chemotherapy drug resistance were assessed in eight OAC cell lines, and miRNA expression profiling was performed via TaqMan OpenArray qPCR. miRNAs discovered were either uniquely associated with resistance to radiation, cisplatin, or 5-FU, or were common to two or all three of the treatments. Target mRNA pathway analyses indicated several potential mechanisms of treatment resistance. miRNAs associated with the in vitro treatment responses were then investigated for association with pathologic response to neoadjuvant chemoradiotherapy (nCRT) in pre-treatment serums of patients with OAC. miR-451a was associated uniquely with resistance to radiation treatment in the cell lines, and with the response to nCRT in patient serums. Inhibition of miR-451a in the radiation resistant OAC cell line OE19 increased radiosensitivity (Survival Fraction 73% vs. 87%, p = 0.0003), and altered RNA expression. Pathway analysis of effected small non-coding RNAs and corresponding mRNA targets suggest potential mechanisms of radiation resistance in OAC.
Publisher: Informa UK Limited
Date: 12-07-2015
DOI: 10.1586/14737159.2015.1052797
Abstract: The role of biomarker assessment in determining the best therapeutic options for patients with metastatic colorectal cancer has become increasingly complex and important. Biomarkers that predict the efficacy and/or toxicity of such treatments can affect medical decision making, leading to decreased harm and/or costs associated with treatment and improvements in therapeutic outcomes for patients. This review discusses traditional and emerging biomarkers of potential clinical utility for patients with metastatic colorectal cancer, current assays and methods used in clinical practice, technologies that have allowed the identification of new biomarkers and key considerations for oncologists and pathologists when determining appropriate biomarker evaluations to be undertaken for their patients.
Publisher: Elsevier BV
Date: 12-2022
Publisher: Springer Science and Business Media LLC
Date: 11-2011
DOI: 10.1007/S00441-011-1263-X
Abstract: The unpleasant sensory and emotional experience of pain is initiated by excitation of primary afferent nociceptive neurons. Nerve damage or inflammation induces changes in nociceptive DRG neurons which contribute to both peripheral and central sensitization of pain-sensitive pathways. Recently, blockade of microRNA synthesis has been found to modulate the response of nociceptive neurons to inflammatory stimuli. However, little is known about the contributions of in idual miRNAs to painful conditions. We compared miRNA expression in mouse sensory neurons and focussed on the localisation and control of miR-143. Using miRNA-arrays we compared the microRNA expression profile of intact lumbar DRG with one-day-old DRG cultures and found that nine miRNAs including miR-143 showed lower expression levels in cultures. Subsequent RT-qPCR confirmed array data and in-situ hybridisation localised miR-143 in the cytosol of sensory DRG neurons in situ and in vitro. Analysis of microbead-enriched neuron cultures showed significantly higher expression levels of miR-143 in isolectin B4 (I-B4) binding sensory neurons compared with neurons in the I-B4 negative flow-through fraction. In animal models of peripheral inflammation (injection of Complete Freund's Adjuvant, CFA) and nerve damage (transection of the sciatic nerve), we found that expression levels of miR-143 were significantly lower in DRGs ipsilateral to CFA injection or after nerve damage. Taken together, our data demonstrate for the first time miR-143 expression in nociceptive neurons. Since expression levels of miR-143 were higher in I-B4 positive neurons and declined in response to inflammation but not axotomy, miR-143 could selectively contribute to mRNA regulation in specific populations of nociceptors.
Publisher: American Association for Cancer Research (AACR)
Date: 08-2014
DOI: 10.1158/1940-6207.CAPR-14-0053
Abstract: High red meat (HRM) intake is associated with increased colorectal cancer risk, while resistant starch is probably protective. Resistant starch fermentation produces butyrate, which can alter microRNA (miRNA) levels in colorectal cancer cells in vitro effects of red meat and resistant starch on miRNA expression in vivo were unknown. This study examined whether a HRM diet altered miRNA expression in rectal mucosa tissue of healthy volunteers, and if supplementation with butyrylated resistant starch (HRM+HAMSB) modified this response. In a randomized cross-over design, 23 volunteers undertook four 4-week dietary interventions an HRM diet (300 g/day lean red meat) and an HRM+HAMSB diet (HRM with 40 g/day butyrylated high amylose maize starch), preceded by an entry diet and separated by a washout. Fecal butyrate increased with the HRM+HAMSB diet. Levels of oncogenic mature miRNAs, including miR17–92 cluster miRNAs and miR21, increased in the rectal mucosa with the HRM diet, whereas the HRM+HAMSB diet restored miR17–92 miRNAs, but not miR21, to baseline levels. Elevated miR17–92 and miR21 in the HRM diet corresponded with increased cell proliferation, and a decrease in miR17–92 target gene transcript levels, including CDKN1A. The oncogenic miR17–92 cluster is differentially regulated by dietary factors that increase or decrease risk for colorectal cancer, and this may explain, at least in part, the respective risk profiles of HRM and resistant starch. These findings support increased resistant starch consumption as a means of reducing risk associated with an HRM diet. Cancer Prev Res 7(8) 786–95. ©2014 AACR.
Publisher: Wiley
Date: 17-10-2017
DOI: 10.1111/NEP.12867
Abstract: Extracellular vesicles, such as exosomes, are present in urine with reports of roles in intercellular signalling and diagnostic utility. However, the extent to which the concentration and characteristics of urinary vesicles are altered in albuminuric renal disease has not been well characterized. In this study, we examined the number and characteristics of extracellular vesicles in albuminuric urine. Vesicles were isolated from the urine of 32 patients with varying levels of albuminuria using ultracentrifugation and density gradient purification and were examined using nanoparticle tracking analysis, immunoblotting and transmission electron microscopy. The size profile of particles in these urine preparations was compared with albumin-containing solutions. Overall, there were no substantial differences in the number, or characteristics, of vesicles released into proteinuric urine. Analysis of albumin-containing solutions showed particles of exosome-like size, suggesting that such particles can mimic exosomes in standard nanoparticle tracking analysis. Albumin and IgG depletion of proteinuric urine resulted in a substantial reduction in the concentration of particles detected by nanoparticle tracking analysis. There was no increase in urinary vesicle concentration in patients with albuminuria. Furthermore, these results demonstrate the need for cautious interpretation of nanoparticle tracking analysis of vesicle concentration in biological fluids containing protein and for sophisticated preparative methods in vesicle purification from urine.
Publisher: Springer Science and Business Media LLC
Date: 24-09-2012
Abstract: Exosomes are nanovesicles secreted by tumour cells which have roles in paracrine signalling during tumour progression, including tumour-stromal interactions, activation of proliferative pathways and bestowing immunosuppression. Hypoxia is an important feature of solid tumours which promotes tumour progression, angiogenesis and metastasis, potentially through exosome-mediated signalling. Breast cancer cell lines were cultured under either moderate (1% O 2 ) or severe (0.1% O 2 ) hypoxia. Exosomes were isolated from conditioned media and quantitated by nanoparticle tracking analysis (NTA) and immunoblotting for the exosomal protein CD63 in order to assess the impact of hypoxia on exosome release. Hypoxic exosome fractions were assayed for miR-210 by real-time reverse transcription polymerase chain reaction and normalised to exogenous and endogenous control genes. Statistical significance was determined using the Student T test with a P value of 0.05 considered significant. Exposure of three different breast cancer cell lines to moderate (1% O 2 ) and severe (0.1% O 2 ) hypoxia resulted in significant increases in the number of exosomes present in the conditioned media as determined by NTA and CD63 immunoblotting. Activation of hypoxic signalling by dimethyloxalylglycine, a hypoxia-inducible factor (HIF) hydroxylase inhibitor, resulted in significant increase in exosome release. Transfection of cells with HIF-1α siRNA prior to hypoxic exposure prevented the enhancement of exosome release by hypoxia. The hypoxically regulated miR-210 was identified to be present at elevated levels in hypoxic exosome fractions. These data provide evidence that hypoxia promotes the release of exosomes by breast cancer cells, and that this hypoxic response may be mediated by HIF-1α. Given an emerging role for tumour cell-derived exosomes in tumour progression, this has significant implications for understanding the hypoxic tumour phenotype, whereby hypoxic cancer cells may release more exosomes into their microenvironment to promote their own survival and invasion.
Publisher: Bentham Science Publishers Ltd.
Date: 16-08-2017
DOI: 10.2174/2211536606666170313114821
Abstract: MicroRNAs (miRNAs) are 17-22 nucleotide, non-coding, single stranded RNA molecules that play a key role in post-transcriptional gene regulation. Hypoxia is a reduction in the normal level of tissue oxygen (O2) tension, and is a feature of chronic vascular disease, pulmonary disease and many cancers. Tissue hypoxia can have widespread effects on cellular functions, as O2 availability is critical for many cellular processes. Cells respond to changes in O2 tension through multiple molecular and cellular mechanisms, including changes in gene expression through transcriptional and translational mechanisms. The transcription factor, hypoxia inducible factor-1, plays a dominant role in transcriptional gene regulation in hypoxia. Several hypoxically induced miRNAs have been shown to play important roles in the hypoxic adaptation of cancer cells. Global repression of enzymes critical for miRNA biogenesis seems to be a widespread phenomenon with several different mechanisms operating. This review describes the effects of hypoxia on specific miRNAs and more global effects on miRNA biogenesis, demonstrating that hypoxia is an important regulator of miRNA biogenesis and function.
Publisher: Informa UK Limited
Date: 19-12-2014
DOI: 10.3109/10641955.2013.832772
Abstract: Pre-ecl sia is a multisystem disorder that occurs in the second half of pregnancy affecting 5% of pregnancies. It remains the leading cause of maternal and perinatal mortality and morbidity worldwide. Impaired placental implantation, hypoxia, endothelial dysfunction and systemic inflammation are thought to have a role in the pathogenesis of pre-ecl sia. MicroRNAs (miRNAs) are short non-coding RNAs. They are important regulators of gene expression and have been found to affect cell development, proliferation, differentiation and function. Specific patterns of miRNAs have been detected in the placenta and there is altered miRNA expression in the placenta of patients with pre-ecl sia to but their role in the pathogenesis remains unclear. Furthermore, deregulated miRNAs have also been reported in human villous trophoblasts during hypoxic stress. One of the more consistently elevated miRNAs by hypoxia and in the placenta of patients with pre-ecl sia is miR-210. Whether such miRNAs are bystander markers of hypoxia, or are directly involved in the pathogenesis of pre-ecl sia, needs to be clarified. There is potential for miRNAs to be used as predictors, markers or therapy in pre-ecl sia. This review provides current knowledge about miRNAs, particularly hypoxia-related miRNAs and the interaction of hypoxia, miRNAs and placenta in pre-ecl sia.
Publisher: Springer Science and Business Media LLC
Date: 08-01-2013
Abstract: Ulceration of the oesophageal squamous mucosa (ulcerative oesophagitis) is a pathological manifestation of gastro-oesophageal reflux disease, and is a major risk factor for the development of Barrett’s oesophagus. Barrett’s oesophagus is characterised by replacement of reflux-damaged oesophageal squamous epithelium with a columnar intestinal-like epithelium. We previously reported discovery of microRNAs that are differentially expressed between oesophageal squamous mucosa and Barrett’s oesophagus mucosa. Now, to better understand early steps in the initiation of Barrett’s oesophagus, we assessed the expression, location and function of these microRNAs in oesophageal squamous mucosa from in iduals with ulcerative oesophagitis. Quantitative real-time PCR was used to compare miR-21, 143, 145, 194, 203, 205 and 215 expression levels in oesophageal mucosa from in iduals without pathological gastro-oesophageal reflux to in iduals with ulcerative oesophagitis. Correlations between microRNA expression and messenger RNA differentiation markers BMP-4, CK8 and CK14 were analyzed. The cellular localisation of microRNAs within the oesophageal mucosa was determined using in-situ hybridisation. microRNA involvement in proliferation and apoptosis was assessed following transfection of a human squamous oesophageal mucosal cell line (Het-1A). miR-143, miR-145 and miR-205 levels were significantly higher in gastro-oesophageal reflux compared with controls. Elevated miR-143 expression correlated with BMP-4 and CK8 expression, and elevated miR-205 expression correlated negatively with CK14 expression. Endogenous miR-143, miR-145 and miR-205 expression was localised to the basal layer of the oesophageal epithelium. Transfection of miR-143, 145 and 205 mimics into Het-1A cells resulted in increased apoptosis and decreased proliferation. Elevated miR-143, miR-145 and miR-205 expression was observed in oesophageal squamous mucosa of in iduals with ulcerative oesophagitis. These miRNAs localised to the basal layer of the oesophageal epithelium. They reduced proliferation and increased apoptosis, and may play roles in regulating epithelial restoration in response to injury caused by gastro-oesophageal reflux.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 27-10-2023
Publisher: Baishideng Publishing Group Inc.
Date: 2010
No related grants have been discovered for Michael Michael.