MicroRNA-302a Sensitizes Tes-Ticular Embryonal Carcinoma Cell To Cisplatin-induced Cell Death

BackgroudCisplatin is a commonly used chemotherapeutic agent for the treatment of sever-al human malignancies such as testicular germ cell tumors (TGCT). The toxic effects persistent or present long after chemotherapy affect the overall quality of life of pa-tients. This is the major problem in testicular cancer treatment. Thus, understanding the mechanism of cisplatin sensitivity and exploring new treatment combinations may have implications for minimizing treatment complications, especially, for those pa-tients with advanced or recurrent testicular cancer.Micro RNA (miRNA) is the fragment of non-coding small RNAs and consists of21-25nucleotides. It can regulated gene expression by either binding to or regulating the translation process of some specific mRNA. MicroRNAs (miRNAs) play im-portant roles in the responses of cancer cells to chemotherapy and have been shown to modulate cell sensitivity to chemotherapeutic drugs. This might useful in the diagno-sis and treatment of cancer. Some research have observed that miR-302family is overexpressed in all malignant TGCT, but not in benign GCTs (teratomas), suggesting that miR-302clusters could be potential serum biomarkers of malignant germ cell tumors. However, the relationship between miRNA expression and cisplatin sensitivi-ty of TGCT has not been fully explored.ObjectiveIn this study, the effects and molecular mechanism of miR-302a on cell prolifera-tion, cell cycle, cell sensitivity and apoptosis were evaluated in TGCT-derived cell line NTERA-2(NT2).MethodsExpression of miR-302a in cisplatin-treated TGCT-derived cell line NTERA-2(NT2) was evaluated by real-time quantitative PCR. Cell proliferation, cell sensitivity, FACS (cell cycle and cell apoptosis) and Western blotting were performed to detect the function and molecular mechanism of miR-302a in miR-302a-overexpressing cells.ResultsWe found that expression level of miR-302a was increased in cisplatin-treated NT2cells. Up-regulation of miR-302a significantly increased the sensitivity of NT2cells to cisplatin by enhancing cisplatin-induced G2/M phase arrest and subsequently progressed to apoptosis. MiR-302a also increased the killing effects of cisplatin by lowering the apoptotic threshold and the same result was also observed in another TGCT-derived cell line NCCIT. Furthermore, miR-302a-enhanced cisplatin sensitivity was partially mediated through down-regulation of p21in NT2cells. MiR-302a in-duced apoptosis was further enhanced by silencing of p53in NT2cells. p53levels were inversely associated with the expression of Oct4, Sox2and Nanog in response to cisplatin.ConclusionThus, targeting miR-302a may offer new therapeutic interventions in TGCT.