Objective  To investigate inhibitory effect and machanism of saikosaponin D (SSd) on the growth and migration of gastric cancer SGC-7901 cells.

  Methods  The SGC-7901 cells were assigned into a control group and low-, moderate-, and high-dose SSd (5, 10, and 20 μmol/L) groups. The cell proliferation was detected with methyl thiazolyl tetrazolium (MTT) assay at 24, 48 and 72 hours of cell culture. The cell apoptosis was measured with terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL). The migration ability of the cells was determined with Transwell. The expression of norrin and livin mRNA were determined with real-time PCR. The cellular expression of norrin, livin, p57, and cyclin E were detected with Western blot.

  Results  The results of MTT assay revealed that the proliferation of the cells treated with SSd was significantly inhibited in a dose-response manner (P < 0.05). Transwell results showed that the number of migration cells of low-, moderate-, and high-dose SSd groups (114 ± 9, 87 ± 6, and 38 ± 4 per field of view) were significantly lower than that of the control group (190 ± 7 per field of view) (P < 0.05 for all); whereas, the cellular apoptosis of the different SSd dose groups (apoptosis index AI: 8.46 ± 1.18, 11.76 ± 2.85, and 34.34 ± 7.74) were significantly increased compared to that of the control group (AI: 4.94 ± 1.14) (all P < 0.05). Compared with the control group, the expressions of norrin and livin mRNA and protein in the cells of moderate- and high-dose SSd groups decreased significantly compared with those of the control group (P < 0.05 for all). The expression of cyclin E protein in cells treated with SSd was significantly decreased but the expression of p57 was significantly increased, with a dose-effect relationship (P < 0.05 for all).

  Conclusion  Saikosaponin D can inhibit the growth and migration of gastric cancer cells by promoting cell apoptosis and affecting cell cycle.