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Reciprocal epigenetic remodeling mediated by polycomb and DNMT3B control testicular cancer hypersensitivity and resistance to 5-aza and cisplatin [DNMT3B Knockdown]

ABSTRACT: We undertook a pharmacogenomic approach in order to better understand mechanisms of hypomethylating agent hypersensitivity of TGCTs by generating a panel of acquired 5-aza resistant TGCT cells and contrasting these to previously generated acquired cisplatin resistance cells from the same parent. Interestingly, there was a reciprocal relationship between cisplatin and 5-aza sensitivity, with cisplatin resistance associated with increased sensitivity to 5-aza and 5-aza resistance associated with increased sensitivity to cisplatin. Unbiased transcriptome analysis revealed 5-aza resistant cells strongly downregulated polycomb target gene expression, the exact opposite of the finding for cisplatin resistant cells which upregulated polycomb target genes. This was associate with a dramatic increase in H3K27me3 and substantial decrease in DNMT3B levels in 5-aza resistant cells, the exact opposite changes seen in cisplatin resistant cells.

ORGANISM(S): Homo sapiens

PROVIDER: GSE172458 | GEO | 2021/12/31

REPOSITORIES: GEO

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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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Reciprocal epigenetic remodeling mediated by polycomb and DNMT3B control testicular cancer hypersensitivity and resistance to 5-aza and cisplatin [DNMT3B Knockdown]

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