MicroRNA-302a sensitizes testicular embryonal carcinoma cells to cisplatin-induced cell death.

Cisplatin is a commonly used chemotherapeutic agent for the treatment of several human malignancies, such as testicular germ cell tumors (TGCT). The toxic effects persist and those that are present long after chemotherapy affect the overall quality of life of patients. MicroRNAs (miRNAs) play important roles in the responses of cancer cells to chemotherapy and have been shown to modulate cell sensitivity to chemotherapeutic drugs. However, the relationship between miRNA expression and cisplatin sensitivity of TGCT has not been fully explored. In this study, the effects of miR-302a on cisplatin cytotoxicity in TGCT-derived cell line NTERA-2 (NT2) were evaluated. We found that expression levels of miR-302a were increased in cisplatin-treated NT2 cells. Up-regulation of miR-302a significantly increased the sensitivity of NT2 cells to cisplatin by enhancing cisplatin-induced G2/M phase arrest and the subsequent progression to apoptosis. MiR-302a also increased the killing effects of cisplatin by lowering the apoptotic threshold; the same result was also observed in another TGCT-derived cell line, NCCIT. Furthermore, miR-302a-enhanced cisplatin sensitivity was partially mediated through the down-regulation of p21 in NT2 cells. MiR-302a induced apoptosis was further enhanced by silencing of p53 in NT2 cells. p53 levels were inversely associated with the expression of Oct4, Sox2, and Nanog in response to cisplatin. Thus, targeting miR-302a may offer new therapeutic interventions in TGCT.