Inhibitory effect of schisandrin B on gastric cancer cells in vitro
【摘要】：AIM: To investigate the inhibitory effect and possible mechanism of action of schisandrin B in SC-B on gastric cancer cells in vitro. METHODS: SC-B consisted of schisandrin B, aloe- emodin, and Astragalus polysaccharides. Exponentially growing human gastric cancer SGC-7901 cells were divided into six treatment groups: (1) control group (RPMI 1640 medium); (2) negative control group (2% DMSO); (3) positive control group (50 mg/L 5-Fluorouracil, 5-FU); (4) low-dose group (LSC, fi nal concentration of schisandrin B, 25 mg/L); (5) moderate-dose group (MSC, fi nal concentration of schisandrin B, 50 mg/L); (6) high- dose group (HSC, fi nal concentration of schisandrin B, 100 mg/L). Follow-up was done at 12-48 h. An MTT (Methylthiazolyldiphenyl-tetrazolium bromide) assay was used to examine the inhibitory effect of SC-B on gastric cancer cells. The mitosis index was assessed using an inverted microscope. Flow cytometry was used to visualize the cell cycle. An RT-PCR (Reverse transcription-Polymerase chain reaction) -based assay was used to detect mRNA expression for cyclin D1 and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). RESULTS: The MTT assay showed that the number of living cells in the LSC, MSC and HSC groups was signif icantly smaller than that in the DMSO-treated group (P 0.05) at 12- 48 h. The inhibitory rate (IR) of the LSC group was 41.15% ± 3.86%, 59.24% ± 5.34% and 69.93% ± 7.81% at 12, 24 and 48 h, respectively. The IR of the MSC group was 42.82% ± 4.94%, 62.68% ± 7.58% and 71.79% ± 8.12% at 12, 24 and 48 h, respectively. The IR of the HSC group was 37.50% ± 3.21%, 40.34% ± 2.98% and 61.99% ± 4.88% at 12, 24 and 48 h, respectively. These results suggested that a moderate dosage had the most obvious inhibitory efficacy at 48 h. Compared to the DMSO group, themitosis index of the LSC, MSC, HSC groups was greatly decreased (P 0.05) at all time points. Any dose of SC-B suppressed mitosis within 12-48 h. Compared to the DMSO group, the percentage of cells in the G0/G1 phase of the MSC group was greatly increased, and that of the S + G2M phase was greatly decreased, while the percentage of cell inhibition (PCI) in the MSC group was greatly increased (P 0.05). This suggested that SC-B could exclusively arrest cells in the G0/G1 phase. Cyclin D1 mRNA expression was lower in the MSC group than that in the DMSO group (P 0.05). CONCLUSION: SC-B can inhibit the proliferation and aberrant mitosis of human gastric cancer SCG-7901 cells in vitro. This inhibitory effect may be due to the down- regulation of cyclin D1 mRNA expression, which causes cell cycle arrest of gastric cancer cells.
【基金】：Supported by The Project of Heilongjiang Natural Science Foundation No. TD 2005-01 Department of Health, Heilongjiang Province No. 2006-391