Effects of microRNA-1271 on ovarian cancer via inhibition of epithelial-mesenchymal transition and cisplatin resistance.

Abstract

Efficacy of platinum based-chemotherapy is limited by cisplatin (DDP) resistance, however, the underlying mechanism of cisplatin resistance remains unclear. We aimed to investigate the role of miR-1271 in cisplatin-resistant ovarian cancer cells. Transfection of miR-1271 mimic and inhibitor was performed to study the role of miR-1271 in ovarian cancer. Cell viability was assessed by Cell Counting Kit (CCK)-8 assay. Flow cytometry was used to determine the apoptosis rates. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot were used to detect mRNA and protein expressions. Target predicted by Targetscan7.2 was confirmed by dual-luciferase activity assay. Mammalian target of rapamycin (mTOR) siRNA (simTOR) co-transfection was performed to verify the role of mTOR in the suppression effect of miR-1271 on ovarian cancer. In SKOV3 cells, miR-1271 overexpression significantly decreased cell viability and up-regulated apoptosis rate (from 5.54% of control to 24.03%). MiR-1271 adversely affected SKOV3 cell migration and invasion, and induced the upregulation of E-cadherin and downregulation of N-cadherin and alpha-smooth muscle actin (α-SMA). Moreover, SKOV3/DDP cells had a lower miR-1271 level, and enhancing miR-1271 contributed strongly to cisplatin-induced apoptosis through altering the expressions of B-cell lymphoma-2 associated X protein (BAX), cleaved caspase-3 and B-cell lymphoma 2 (Bcl-2). In contrast, the opposite result was observed in miR-1271 inhibitor. mTOR was identified to be a target of miR-1271. SimTOR partially reversed the increased cell viability under the effect of miR-1271 inhibitor. Our data indicate that miR-1271 can inhibit the ovarian cancer epithelial-mesenchymal transition (EMT) and sensitize resistant cells to cisplatin-induced apoptosis through blocking mTOR expression.