OBJECTIVETo explore the effect of Rg3 on inhibiting and inducing apoptosis of bladder cancer cells.

METHODThe bladder cancer cell line EJ was treated with Rg3 of various concentrations. Cell proliferation was measured by MTT assay. Morphological changes of cells were observed by fluorescent staining of Hoechst 33258. Cell cycle and apoptosis rate were analyzed by flow cytometry (FCM). The expression of caspase-3 in cells was detected by immunocytochemistry. DNA ladder was showed by agarose gel electrophoresis.

RESULTRg3 inhibited proliferation of EJ cells in a manner of concentration-dependent relationship, IC50 of Rg3 in 48 h treatment was 125.5 mg x L(-1) to EJ cells. When treated with 150 mg x L(-1) of Rg3 for 24 h and 48 h, the cells showed apoptotic morphological characteristics including the condensed chromatin, the nuclear fragmentation, the apoptotic body and bright fluorescent granules as well as a higher caspase-3 expression. FCM assay indicated that Rg3 regulated cell cycle and induced apoptosis of EJ cells. When treated for 24 h and 48 h with 75 mg x L(-1) of Rg3 as well as for 48 h with 150 mg x L(-1) of Rg3, the percentages of cells in S phase and G2/M phase were increased, whereas the percentage of cells in G0-G1 was decreased. The apoptosis rates were increased from (1.05 +/- 0.17)% in control group cells to (8.41 +/- 0.98)%, (18.57 +/- 2.20)% and (33.98 +/- 1.64)%, respectively. Remarkable DNA ladders were revealed. The effects showed a manner in dose and time dependent of Rg3.

CONCLUSIONThe results suggest that ginsenoside Rg3 exerts an inhibiting effect on proliferation of EJ cells by inducing apoptosis.