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.

Project description:The ATP binding cassette (ABC) transporter family is widely distributed in vertebrates and is essential for drug resistance, cell signaling and energy homeostasis. There is growing evidence that various ABC transporters contribute to the growth and development of tumors but relatively little is known about how the ABC transporter family behaves in hepatocellular carcinoma (HCC). ABCC6 transporter was downregulated in HCC tissues and that it was associated with successful treatment for HCC patients. Cellular model studies have shown that ABCC6 plays a role in the migration and cytoskeleton rearrangement of HepG2 hepatocarcinoma cells, highlighting its role in cancer biology. Abcc6-silenced HepG2 cells are used as cell model to obtain more deep information about the molecular mechanisms underlying the observed results. MTT and colony formation assays, showed the effects of Abcc6 on HepG2 cell proliferation. Western blotting analysis, real-time PCR, and immunofluorescence were used to find the E-cadherin, Vimentin, and N-cadherin markers associated with the epithelial-to-mesenchymal transition (EMT). Colony formation experiments in the current study showed that Abcc6 decreased HepG2 cell viability. The migratory and invasion activities were dramatically slowed down by Abcc6 silencing, according to the Transwell and wound-healing assays. In tumor cells, EMT has been shown to be crucial for enhancing migration and invasion and is frequently characterized by a loss of epithelial markers (E-cadherin) and an increase in mesenchymal markers (Vimentin and N-cadherin). In the western blotting examination, E-cadherin expression was considerably elevated compared to the control group, while N-cadherin and Vimentin expression were downregulated. This led to the hypothesis that the underlying mechanism of Abcc6 knockdown prevents migration and invasion in HepG2 cells and is linked to the suppression of EMT. In conclusion all evidence suggested that ABC transporters play a more active role in cancer biology.

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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Expression profile of etoposide-resistant MCF7 (MCF7VP) cells with targeted RUNX2 knockdown

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