Aim: To study the effect of staurosporine (ST) on the cell cycle of human gastric cancer cell lines MGC803 and SGC7901.
Methods: Cell proliferation was evaluated by trypan blue dye exclusion method. Apoptotic morphology was observed under a transmission electron microscope. Changes of cell cycle and apoptotic peaks of cells were determined by flow cytometry. Expression of p21WAF1 gene was examined using immunohistochemistry and RT-PCR.
Results: The growth of MGC803 and SGC7901 cells was inhibited by ST. The inhibitory concentrations against 50% cells (IC50) at 24 h and 48 h were 54 ng/ml and 23 ng/ml for MGC803, and 61 ng/ml and 37 ng/ml for SGC7901. Typical apoptotic bodies and apoptotic peaks were observed 24 h after cells were treated with ST at a concentration of 200 ng/ml. The percentage of cells at G0/G1 phase was decreased and that of cells at G2/M was increased significantly in the group treated with ST at the concentrations of 40 ng/ml, 60 ng/ml, 100 ng/ml for 24 h, compared with the control group (P<0.01). The expression levels of p21WAF1 gene in both MGC803 and SGC7901 cells were markedly up-regulated after treatment with ST.
Conclusion: ST can cause arrest of gastric cancer cells at G2/M phase, which may be one of the mechanisms that inhibit cell proliferation and cause apoptosis in these cells. Effect of ST on cells at G2/M phase may be attributed to the up-regulation of p21WAF1 gene.