Anti-Proliferation Effects and Molecular Mechanisms of Action of Tetramethypyrazine on Human SGC-7901 Gastric Carcinoma Cells

Aim: To investigate the effects of tetramethypyrazine (TMP) on proliferation and apoptosis of the humangastric carcinoma cell line 7901 and its possible mechanism of action.
Methods: The viability of TMP-treated7901 cells was measured with a 3-(4, 5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide assay (MTT)and cell apoptosis was analyzed by flow cytometry. The distribution of cells in different phases of cell cycle afterexposure of TMPs was analyzed with flow cytometry. To investigate the molecular mechanisms of TMP-mediatedapoptosis, the expression of NF-κBp65, cyclinD1 and p16 in SGC-7901 cells was analyzed by reverse transcriptionpolymerasechain reaction (RT-PCR) and western blotting.
Results: TMP inhibited the proliferation of humangastric carcinoma cell line 7901 in dose and time dependent manners. Cell growth was suppressed by TMP atdifferent concentrations (0.25, 0.5, 1.0, 2.0 mg/ml), the inhibition rate is 0.46%, 4.36%, 14.8%, 76.1% (48h) and15.5%, 18.5%, 41.2%, 89.8% (72h) respectively. When the concentration of TMPs was 2.0mg/ml, G1-phasearrest in the SGC-7901 cells was significant based on the data for cell cycle distribution. RT-PCR demonstratedthat NF-κBp65 and cyclin D1 mRNA expression was significantly down-regulated in 7901 cells treated with 2.0mg/ml TMP for 72h (p<0.05), while the p16 mRNA level was up-regulated (p<0.05). The protein expression ofNF-κBp65 and cyclin D1 decreased gradually with the increase in TMP concentration, compared with controlcells (p<0.05), while expression of protein p16 was up-regulated (p<0.01).
Conclusion: TMP exhibits significantanti-proliferative and pro-apoptotic effects on the human gastric carcinoma cell line SGC-7901. NF-κBp65,cyclinD1 and p16 may also play important roles in the regulation mechanisms.