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MicroRNA expression for 86 chemo-treated ovarian cancer patients

ABSTRACT: We profile expression in serous epithelial ovarian carcinomas to assess the possibility of an miRNA signature associated with chemoresistance. Resistance to the available therapies is one of the main causes of low survival of patients with advanced epithelial ovarian cancer, thus representing an emergency in oncology. Here, we profiled miRNA expression in 86 naïve serous epithelial ovarian carcinomas (EOCs) to assess the possibility of miRNAs associated with chemoresistance. We identified 23 miRNAs associated with chemoresistance, of which three (miR-484, miR-642 and miR-217) were confirmed in the validation set (112 independent patients). The study of miR-484 role demonstrated that it regulated the chemoresistance of EOC cells acting not on cancer cells but on tumor vasculature. In particular, miR-484 is produced and secreted by chemosensitive EOC, therefore regulating the production of VEGFB by cancer cells and the expression of VEGFR2 in endothelial cells. Overall, we demonstrated that a three-miR signature can classify the response to chemotherapy and that chemoresistance in EOC relays, at least in part, on the control of tumor angiogenesis, indicating new options in the treatment of these patients.

ORGANISM(S): Homo sapiens

PROVIDER: GSE43867 | GEO | 2013/05/17

SECONDARY ACCESSION(S): PRJNA187976

REPOSITORIES: GEO

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Project description:Previously, we have identified the polypeptide N-acetylgalactosaminyltransferase 3 (GALNT3) gene as notably hypomethylated in low-malignant potential (LMP) and high-grade (HG) serous epithelial ovarian tumors, compared to normal ovarian tissues. Here we show that GALNT3 is strongly overexpressed in both LMP and HG serous EOC tumors, thus suggesting that epigenetic mechanisms might be implicated in GALNT3 overexpression in serous epithelial ovarian cancer (EOC). Moreover, GALNT3 expression significantly correlated with shorter progression-free survival (PFS) periods in serous EOC patients with advanced disease. Knockdown of the GALNT3 expression in EOC cells led to sharp decrease of cell proliferation and induced S-phase cell cycle arrest. Additionally, GALNT3 suppression significantly inhibited EOC cell migration and invasion. Gene expression profiling and consecutive network and pathway analyses confirmed these findings, as numerous genes and pathways known previously to be implicated in ovarian tumorigenesis, including EOC tumor invasion and metastasis, were found to be downregulated upon GALNT3 suppression, while some tumor suppressor genes were induced. Moreover, GALNT3 downregulation was associated with reduced MUC1 protein expression in EOC cells, probably related to destabilization of the MUC1 protein due to lack of GALNT3 glycosylation activity.Taken together, our data are indicative for a strong oncogenic potential of the GALNT3 gene in advanced EOC and identify this transferase as a novel EOC biomarker and putative EOC therapeutic target. Our findings also suggest that GALNT3 overexpression might contribute to ovarian etiology through aberrant mucin O-glycosylation. To better understand the molecular mechanisms of GALNT3 gene action in ovarian cancer cells, we employed the Agilent Whole Human Genome microarrays, containing ~ 44,000 genes to identify global gene expression changes upon GALNT3 suppression in A2780s cells. We compared the gene expression of the previously selected clone shRNA- GALNT3-knockdown clones 1 & 2 (sh-cl1 & sh-cl2) against the corresponding control (ctrl) clone. The microarray experiments were performed in duplicates, as four hybridizations were carried out for the GALNT3-suppressing cell clones against the corresponding control, using a fluorescent dye reversal (dye-swap) technique.

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MicroRNA expression for 86 chemo-treated ovarian cancer patients

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