Effects of diosgenin on autophagy of human osteosarcoma cells / 中成药

ABSTRACT

AIM To investigate the effects of diosgenin on autophagy of human osteosarcoma cells.METHODS Human osteosarcoma MG63 and U2OS cells with or without exposure to diosgenin had their proliferation detected by MTT assay,their ultrastructure observed by transmission electron microscopy,their expression of autophagy protein Beclin1 observed by immunofluorescence staining,and their expressions of autophagy molecular markers LC3,Beclin1 and PI3K/Akt/mTOR signaling pathway related proteins detected by Western blot.The MG63 and U2OS cells cotreated with diosgenin and PI3K pathway inhibitor LY294002 had the expression of Beclin1 mRNA detected by RT-qPCR.The MG63 and U2OS cells cotreated with autophagy inhibitor 3-methyladenine(3-MA)had their inhibition rate of proliferation detected by MTT assay,their expression of cleaved-caspase3 protein detected by Western blot,and their expression of caspase3 mRNA detected by RT-qPCR.RESULTS Upon osteosarcoma MG63 and U2OS cells,diosgenin inhibited their proliferation,promoted the generation of autophagosomes,increased the protein expression of LC3 Ⅱ and Beclin1(P<0.05,P<0.01),reduced the protein expression of LC3 I(P<0.01),and inhibited the protein phosphorylation level of PI3K/Akt/mTOR pathway(P<0.05,P<0.01),whose effects were offset by the intervention with autophagy inhibitors in terms of the reduced proliferation inhibition and down-regulated expressions of caspase3 mRNA and cleaved-caspase3 protein(P<0.01).CONCLUSION Diosgenin can inhibit the proliferation of osteosarcoma cells and induce their autophagy leading to their death and autophagy apoptosis,which may be related to the activation of PI3K/Akt/mTOR signaling pathway and up-regulation of the expression of LC3 Ⅱ and Beclin1 proteins.