Project description:Background: Current protocols for the treatment of ovarian cancer include combination chemotherapy with a platinating agent and a taxane. However, many patients experience relapse of their cancer and the development of drug resistance is not uncommon, making successful second line therapy difficult to achieve. The objective of this study was to develop a cell line resistant to both carboplatin and docetaxel (dual drug resistant ovarian cell line A2780CBNDXL), along with single agent resistant lines (docetaxel resistant A2780DXL and carboplatin resistant A2780CBN), to investigate the mechanisms which underlie the development of dual drug resistance. Methods: The A2780 epithelial ovarian cancer cell line was used to select for isogenic carboplatin, docetaxel and dual drug resistant cell lines. A selection method of gradually increasing drug doses was implemented to avoid clonal selection. Resistance was confirmed using a clonogenic assay. Changes in gene expression associated with the development of drug resistance were determined by microarray analysis compared to parental co-culture control A2780CC. Changes in selected genes were validated by QPCR and immunoblotting. Results: Three isogenic cell lines were developed and resistance to each drug or the combination of drugs was confirmed. Development of resistance was accompanied by a reduced growth rate. The microarray and QPCR analyses showed that unique changes in gene expression occurred in the dual drug resistant cell line and that genes known to be involved in resistance could be identified in all cell lines. Conclusions: Novel changes in gene expression can occur in the development of dual drug resistance, indicating that dual drug resistance is not a simple combination of the changes occurring in single agent resistance Carboplatin, docetaxel (GSE26129) and carboplatin/docetaxel dual resistant cell lines of ovarian A2780 were generated for gene expression profilling. Two colour microarray of Agilent whole human genome nucleotide arrays was conducted with two replicate of both forward and reverse labellings for each cell line. Four arrays were used for this experiments. And it was four replicate of both forward and reverse labellings for A2780 cells. Eight arrays were used for this experiments

Project description:Drug resistance poses a major challenge to ovarian cancer treatment. Understanding mechanisms of drug resistance is important for finding new therapeutic targets. In the present work, a cisplatin-resistant ovarian cancer cell line A2780-DR was established with a resistance index of 6.64. The cellular accumulation of cisplatin was significantly reduced in A2780-DR cells as compared to A2780 cells consistent with the general character of drug resistance. Quantitative proteomic analysis identified 340 differentially expressed proteins between A2780 and A2780-DR cells, which involve in diverse cellular processes, including metabolic process, cellular component biogenesis, cellular processes and stress responses. Expression levels of Ras-related proteins Rab 5C and Rab 11B in A2780-DR cells were lower than those in A2780 cells as confirmed by real-time quantitative PCR and western blotting. The short hairpin (sh)RNA-mediated knockdown of Rab 5C in A2780 cells resulted in markedly increased resistance to cisplatin whereas overexpression of Rab 5C in A2780-DR cells increases sensitivity to cisplatin, demonstrating that Rab 5C-dependent endocytosis plays an important role in cisplatin resistance. Our results also showed that expressions of glycolytic enzymes PKM, GPI, Aldolase, LDH, and PGK were down-regulated in drug resistant cells, indicating drug resistance in ovarian cancer is directly associated with a decrease in glycolysis. Furthermore, it was found that glutathione reductase were up-regulated in A2780-DR, while vimentin, HSP90, and Annexin A1 and A2 were down-regulated. Taken together, our results suggest that drug resistance in ovarian cancer cell line A2780 is caused by multifactorial traits, including the down-regulation of Rab 5C-dependent endocytosis of cisplatin, glycolytic enzymes and vimentin, and up-regulation of antioxidant proteins, suggesting Rab 5C is a potential target for treatment of drug-resistant ovarian cancer. This constitutes a further step towards a comprehensive understanding of drug resistance in ovarian cancer.

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Beta-microseminoprotein (MSMB) downregulation is associated with increased drug resistance in ovarian cancer

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