Effects of rapamycin on proliferation and apoptosis of human osteosarcoma cells in vitro

Objective To observe the effects of rapamycin (RAPA) on the proliferation and apoptosis of osteosarcoma U-2OS and Saos-2 cells and the action mechanism.Methods U-2OS and Saos-2 cells were cultured in vitro.The methyl thiazolyl tetrazoliun (MTT) and flow cytometry methods were used to detect the effects of different concentrations of rapamycin on the proliferation and apoptosis of osteosarcoma cells.The expression of Fas protein was detected by Western blotting.Results Rapamycin could inhibit the proliferation of human osteosarcoma cells.When the concentration of rapamycin reached 20 nmol/L,the inhibition was increased significantly,P ＜0.05,The inhibition rate was 31.2％ and 28.7％ in U-2OS and Saos-2 cells respectively.The apoptosis rate was increased notably when the concentration of rapamycin reached 20 nmo/L ( P ＜ 0.05 ).The protein expression of Fas was significantly increased when the rapamycin was given 48 h later.Conclusion Rapamycin could inhibit the proliferation and induce apoptosis of human osteosarooma U-2OS and Saos-2 cells.It might play its role through increasing the protein expression of Fas. Key words: Rapamycin; Osteosarcoma; Fas