Antitumor mechanism of ursolic acid on human gastric cancer cell lines SGC7901 in vitro

Objective To investigate the potential mechanism of inhibition of ursolic acid(UA) on growth of human gastric cancer cell lines SGC7901 in vitro.Methods SGC7901 cells were cultured in vitro,MTT assay was used to observe the effect of UA on growth of SGC7901 cells in various concentrations for different times.After SGC7901 cells were treated by 0—40 μmol/L UA for 24 h,morphological changes were observed by inverted microscope.Apoptotic changes were detected by fluorescence microscopy and flow cytometry (FCM).Protein expressions of Bcl-2 and Bax were determined by Western blotting.Results UA(20—40 μmol/L) could significantly inhibit the growth of SGC7901 cells in a(dose-and) time-dependent manner,the IC_(50) value of UA for SGC7901 cells for 12,24,36,and 48 h were((57.50±)1.18),(34.28±2.05),(27.54±1.11),and(24.83±1.02) μmol/L,respectively.After UA((20—)40 μmol/L) treatment for 24 h,SGC7901 cells turned round and floated at different levels;SGC7901 cells were arrested at G_0/G_1 phase and apoptosis was induced,and the apoptotic rate was increased along with the increase of UA concentration.Meanwhile Bcl-2 protein expression decreased,whereas Bax protein expression unchanged.Conclusion UA has a stronger antitumor effect on SGC7901 cells.Cytotoxic effect,proliferation inhibition,and apoptosis may be involoved in the mechanism of UA,and the apoptosis caused by UA may be enhanced by decrease of Bcl-2 protein expression.