Inhibitory effect of schisandrin B on gastric cancer cells in vitro.
OBJECTIVE
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, final concentration of schisandrin B, 25 mg/L); (5) moderate-dose group (MSC, final concentration of schisandrin B, 50 mg/L); (6) high-dose group (HSC, final 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 significantly 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, the mitosis 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).


CONCLUSIONS
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.
Liu
Xiao-Ni
XN
Department of Physiology, Mudanjiang Medical College, Mudanjiang 157011, Heilongjiang Province, China. lxnlxm@126.com
Zhang
Cheng-Yu
CY
Jin
Xiu-Dong
XD
Li
Yue-Zhen
YZ
Zheng
Xue-Zhi
XZ
Li
Li
L
D027883:Astragalus Plant; D002453:Cell Cycle / Q000187:drug effects*; D045744:Cell Line, Tumor; D019938:Cyclin D1 / Q000378:metabolism; D034242:Cyclooctanes / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004365:Drugs, Chinese Herbal; D004642:Emodin / Q000031:analogs & derivatives / Q000494:pharmacology; D005960:Glucosides / Q000494:pharmacology; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000378:metabolism; D006801:Humans; D017705:Lignans / Q000494:pharmacology*; D008516:Medicine, Chinese Traditional; D008938:Mitosis / Q000187:drug effects*; D011083:Polycyclic Compounds / Q000494:pharmacology*; D011134:Polysaccharides / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D013274:Stomach Neoplasms / Q000378:metabolism / Q000473:pathology*; D013997:Time Factors
D034242:Cyclooctanes; D004365:Drugs, Chinese Herbal; D005960:Glucosides; D017705:Lignans; D011083:Polycyclic Compounds; D011134:Polysaccharides; D012333:RNA, Messenger; C407723:aloe-emodin 1-O-glucopyranoside; C015499:schizandrin B; D019938:Cyclin D1; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D004642:Emodin