Study of Arctiin and Arctigenin in Inducing Non-apoptotic Death of Human Prostate Cancer PC3 Cells

Objective To investigate the effect of arctiin(ARC) and arctigenin(ARG) on human prostate cancer PC3 cells,and to explore their relevant mechanisms.Methods PC3 cells were cultured with ARC or ARG at various concentrations.Cell survival was measured by methyl thiazolyl tetrazolium(MTT) assay.Morphological changes of cells before and after treatment were observed by Rui Ji's dye staining.Apoptosis and necrosis of PC3 cells were detected by Annexin V-FITC/PI staining with flow cytometer.The expression of apoptosis-related proteins such as Bcl-2,Bax and Caspase 3 was detected by western blotting method.Results The proliferation of PC3 cells was inhibited by both ARC and ARG in time-and dose-dependent manner,and the cell survival rate within 48h was significantly lower than that within 24 h(P0.01).The cells treated with ARG or ARC showed obvious morphological changes such as retraction of cellular membrane,cell membrane attaching closely to the nucleus,reduction of cytoplasm,and obvious fibra network structure in the enchylema.Compared with blank control group,the Annexin V-FITC/PI double staining rate as well as PI single dye rate at concentrations of 20 μmol/L and 5 μmol/L was significantly increased in ARG-or ARC-treated cells(P0.05 or P0.01)showed by the results of flow cytometry,but the Annexin V-FITC single dye rate had no significant changes(P0.05).Western blot analysis revealed that the expression level of Bcl-2 was reduced after PC3 cells had been treated with ARG or ARC for 48h(P0.01),but Bax and Caspase-3 had no significant changes(P0.05).Conclusion ARC and ARG may induce the death of PC3 cells in a non-apoptotic way,and the mechanism is probably related with the down-regulation of Bcl-2 expression.