Downregulation of Cdk1 and cyclinB1 expression contributes to oridonin-induced cell cycle arrest at G2/M phase and growth inhibition in SGC-7901 gastric cancer cells.

BACKGROUND Oridonin isolated from Rabdosia rubescens, a plant used to treat cancer in Chinese folk medicine, is one of the most important antitumor active ingredients. Previous studies have shown that oridonin has anti- tumor activities in vivo and in vitro, but little is known about cell cycle effects of oridonin in gastric cancer. MATERIALS AND METHODS MTT assay was adopted to detect the proliferation inhibition of SGC-7901 cells, the cell cycle was assessed by flow cytometry and protein expression by Western blotting. RESULTS Oridonin could inhibit SGC-7901 cell proliferation, the IC50 being 15.6 μM, and blocked SGC-7901 cell cycling in the G2/M phase. The agent also decreased the protein expression of cyclinB1 and CDK1. CONCLUSIONS Oridonin may inhibit SGC-7901 growth and block the cells in the G2/M phase by decreasing Cdk1 and cyclinB1 proteins.