miR-214 modulates cisplatin sensitivity of osteosarcoma cells through regulation of anaerobic glycolysis.

Osteosarcoma is the most frequent primary bone tumor originating from adolescents and young adults. Despite improvements in the chemo- or radio- therapy of osteosarcoma patients, survival rate has not increased and drug resistance becomes a major factor that limits the effectiveness. Therefore, investigation of new treatment modalities is urgently required to optimize therapeutic options. Our previous study described an oncogenic role of miR-214 through promotion of osteosarcoma cells proliferation. In this study, we report miR-214 contributes to cisplatin resistance in osteosarcoma cells. Overexpression of miR-214 decreased the cisplatin sensitivity. By establishing an osteosarcoma cisplatin resistant cell line, we find miR-214 is significantly upregulated in cisplatin resistant cells. Moreover, we show miR-214 promotes anaerobic glycolysis rates of osteosarcoma cells but suppresses mitochondrial oxidative phosphorylation. Consistently, cisplatin resistant cells exhibit upregulated glycolysis but decreased mitochondrial oxidative phosphorylation, a phenotype called "Warburg effect". Finally, we demonstrate inhibition of glycolysis by either glycolysis inhibitor or miR-214 inhibition significantly re-sensitizes cisplatin resistant osteosarcoma cells. In summary, this study illustrates a miRNA-involved chemosensitivity of osteosarcoma and will contribute to the developments of therapeutic agents for the anti-chemoresistance treatments.