MiR-634 restores drug sensitivity in resistant ovarian cancer cells by targeting the Ras-MAPK pathway
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ABSTRACT: The development of drug resistance is still a major impediment for the successful treatment of cancer, such as advanced stage ovarian cancer, which has a 5-year survival rate of only 30%. The molecular processes that contribute to resistance have been extensively studied, however, not much is known about the role of microRNAs. We compared microRNA expression profiles of three isogenic cisplatin sensitive and resistant cell line pairs. The only microRNA that was consistently downregulated (FDR = 0.000) in all resistant cell lines was miR-634. We investigated the effects of miR-634 modulation in ovarian cancer cell lines and patient derived tumor cells. Overexpression of miR-634 gave rise to a modest G1 phase block and enhanced apoptosis. Furthermore, miR-634 resensitized resistant ovarian cancer cell lines and patient derived tumor cells to cisplatin chemotherapy. Similarly, miR-634 enhanced the response of tumor cells to carboplatin and doxorubicin, but not to paclitaxel. We showed that miR-634 regulates cyclin D1 (CCND1), which is required for the G1-S phase transition, explaining the effects on the cell cycle. In addition, miR-634 repressed expression of GRB2, ERK2, RSK1 and RSK2, components of the Ras-MAPK pathway. Altogether, our findings suggest that miR-634 modulates several cancer relevant targets and therefore miR-634 is an attractive therapeutic candidate to resensitize chemotherapy resistant ovarian tumors. The miRNA expression profile was determined of three cisplatin sensitive/resistant cell line pairs (ovarian cancer cell line pair A2780/A2780 DDP; colon cancer cell line pair HCT8/HCT8 DDP; bladder cancer cell line pairT24/T24 DDP10).
ORGANISM(S): Homo sapiens
SUBMITTER: Erik Wiemer
PROVIDER: E-GEOD-54665 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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