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.