Effect of PI3K-mediated autophagy in human osteosarcoma MG63 cells on sensitivity to the chemotherapy drug cisplatin

Objective: To investigate the influence of autophagy on sensitivity to the chemotherapy drug cisplatin(DDP) and the role of PI3 K in autophagy. Methods: MTT methods and l ow cytometer, with rapamycin up-regulating the autophagy and 3-MA down-regulating the autophagy, were employed to measure the proliferation inhibition rate on DDP-treated osteosarcoma cells and the change in cell cycle. The expression of intracellular protein was detected by Western blot. The autophagy of MG63 cell was observed using l uorescence microscope and transmission electron microscope. Results: Western blot showed that basic autophagy level of MG63 cell was significantly lower than that of h FOB cell. MTT test revealed that the cell proliferation inhibition rate in the group treated with rapamycin and DDP, group treated with 3-MA and DDP, and group only treated with DDP was signii cantly dif erent. It was demonstrated by the l ow cytometry that in group treated with DDP, inhibition on autophagy can increase the cell numbers in G1 phase and reduce the cell numbers in S phase of cell cycle. Increase of autophagosome in MG63 cytoplasm was observed under l uorescence microscope. Conclusions: Up-regulating the autophagy signii cantly reduced the sensitivity of MG63 cell to chemotherapy with DDP. DDP induced autophagy of MG63 cell and blocked the cell cycle at G1 phase.