Induction of apoptosis by berbamine in androgen-independent prostate cancer cell PC-3 in vitro

Objective To investigate the effects of berbamine on cell proliferation and apoptosis of PC-3 in vitro and the possible mechanisms involved.Methods The A values of PC-3 in each group with various concentrations(10,20,30,40 mg/L)of berhamine at various time intervals(24,48,72 h) were detected with the MTT.The apoptosis rate and cell cycle of the PC-3 cells treated with berbamine were assessed by flow cytometry analysis.Transmission electron microscope was employed for the cell ap- optosis.Immunohistochemical technique was used to determine the expression of bax,bcl-2 and survivin proteins after treatment with berbamine.Results After PC-3 cells were treated with 10,20,30 and 40 mg/L berbamine for 48 h,the inhibition ratio was(13.60±1.49)%,(31.79±2.31)%,(54.16±3.09)% and(63.72±2.46)% respectively(compared with the controls,P0.05).Cell proliferation of prostate cancer cell PC-3 was markedly inhibited by berbamine in a time-and-dose dependent manner.Af- ter PC-3 cells were incubated with 40 mg/L berbamine for 24,48 and 72 h,the cell apoptotic rate was (31.44±3.27)%,(50.32±4.03)% and(63.46±3.75)% respectively(compared with the controls, P0.05).With the increase of berbamine concentration,the ratio of G_0/G_1 and S cells was increased and the ratio of G_2/M was decreased.Under the transmission electron microscopy,the apoptosis body was seen. Immunohistochemical technique showed the expression of bax in the PC-3 cells treated with 40 mg/L of berbamine was significandy increased and survivin significantly decreased(P0.05).There was no sig- nificant changes in the expression of bcl-2(P0.05).Conclusion Berbamine can inhibit the prolifera- tion of PC-3 cells by inducing apoptosis and affecting cell cycle in vitro in a time-and-dose-dependent manner.Berbamine induces apoptosis by down-regulating the expression of survivin protein and up-regula- ting the expression of bax protein.