HIF1A and osteosarcoma: As we expected, restoration of HIF-1α expression in miR-199a overexpressing cells led to a significant tolerance to cisplatin compared with the transfection with control vector in miR-199a overexpressing cisplatin resistant cells (Figure 6B), confirming that overexpression of miR-199a sensitizes cisplatin resistant osteosarcoma cells to cisplatin by the inhibition of HIF-1α.