Geranium thunbergii extract-induced G1 phase cell cycle arrest and apoptosis in gastric cancer cells.

Geranium thunbergii is a traditional East Asian medicine for stomach diseases including dysentery and stomach ulcers in East Asia and has been reported to possess biological activity. The benefits of G. thunbergii in gastric cancer are unknown. In this study, we demonstrate that G. thunbergii extract suppresses proliferation and induces death and G1/S cell cycle arrest of gastric cancer cells. Proliferation was significantly inhibited in a time- and dose-dependent manner. Cell cycle arrest was associated with significant decreases in CDK4/cyclinD1 complex and CDK2/cyclinE complex genes expression. In addition, the protein expression of caspase-3 was decreased and that of activated poly (ADP-ribose) polymerase (PARP) was increased, which indicated apoptosis. The expressions of the Bax and Bcl-2, which are apoptosis related proteins, were upregulated and down-regulated, respectively. The results indicate that G. thunbergii extract can inhibit proliferation and induce both G/S cell cycle arrest and apoptosis of gastric cancer cells. Also, the induction of apoptosis involved the intrinsic pathways of the cells. Take the results, we suggest that G. thunbergii extract has anti-gastric cancer activity and may be a potential therapeutic candidate for gastric cancer.