[Effects of Betulinic acid on apoptosis in human gastric cancer SGC-7901 cells].

Objective: To investigate the effects of betulinic acid on apoptosis of human gastric cancer SGC-7901 cells. Methods: The human gastric cancer SGC-7901cells were divided in to 4 groups, and each group was set with 3 replicates. The SGC-7901cells in control group were not treated with betulinic acid; the other 3 experimental groups were treated with betulinic acid at the concentrations of 10, 20 and 30 mg/L, respectively; each group was incubated in a 5% carbon dioxide incubator for 48 h. Laser confocal microscope was used to observe morphological changes of SGC-7901 cells; Flow cytometry was applied to determine apoptosis rate and mitochondrial membrane potential. The mRNA and protein levels of Bcl-2 , Bax and Caspase-3 were also detected by qRT-PCR and western blot respectively. Results: Compared with the control group, SGC-7901 cells in the treated group at final concentrations of 10, 20 and 30 mg/L shrinked, appeared apoptosis body along with nuclear splitting. The percentage of cells in early and advanced period of apoptosis were markedly increased ( P ＜0.05 or P ＜0.01), mitochondrial membrane potential was obviously reduced ( P ＜0.05 or P ＜0.01). qRT-PCR and western blot analysis showed that the mRNA and protein expressions of Bax and Caspase-3 were increased significantly ( P ＜0.01), while the expressions of Bcl-2 were decreased significantly ( P ＜0.01). Conclusion: Within a certain range of concentrations, betulinic acid induces cell apoptosis by regulating the expression of Bcl-2 , Bax and Caspase-3 in human gastric cancer.