过氧化物酶体增殖剂激活受体-γ在白藜芦醇抑制胃癌SGC-7901细胞增殖中的作用

Role of peroxisome proliferator-activated receptor-γin resveatrol-induced proliferation inhibition of gastric cancer cell line SGC-7901

目的:探讨过氧化物酶体增殖剂激活受体-γ(PPAR-γ)在白藜芦醇(Res)抑制人胃癌细胞SGC-7901增殖中的作用.方法:体外常规培养人胃癌细胞SGC-7901,MTT法检测Res和GW9662(PPAR-γ特异阻断剂)对SGC-7901细胞的增殖抑制作用,流式细胞仪测定对细胞周期的影响,RT-PCR方法检测PPAR-γ,Cyclin D1的mRNA表达,Western blot检测PPAR-γ蛋白的表达,免疫细胞化学检测Cyclin D1蛋白表达的改变.结果:Res以时间、浓度依赖性方式抑制胃癌细胞SGC-7901的增殖(P<0.05),使细胞周期停留在G1期;胃癌细胞SGC-7901存在PPAR-γmRNA和蛋白的表达,Res呈浓度依赖性的激活PPAR-γmRNA的转录.25,50,75,100μmol/L Res作用于胃癌细胞后,细胞中PPAR-γmRNA相对表达分别是空白对照组的122.2%,195.1%,232.9%和277.1%(P<0.05),而PPAR-γ蛋白的表达几乎没有变化;胃癌SGC-7901细胞高水平表达Cvclin D1,Res显著的抑制Cyclin D1的表达.经25,50,75,100μmol/L Res处理后,Cyclin D1 mRNA抑制率分别为11.3%,24.3%,35.4%,59.5%,而GW9662能够明显降低Res的上述作用.结论:Res在胃癌SGC-7901细胞中部分的通过激活PPAR-γ从而抑制Cyclin D1的表达,使癌细胞停留在G1期,抑制细胞的增殖.

AIM： To investigate the role of peroxisome proliferator-activated receptor-γ（PPAR-γ） in the inhibitory effects of resveratrol （Res） on gastric cancer cell SGC-7901 proliferation in vitro. METHODS： After human gastric cancer cell SGC-7901 was cultured in vitro, MTT assay was used to detect the inhibitory effect of Res and GW9662 （specific blocker of PPAR-γ） on cell proliferation. Flow cytometry was used to detect cell cycle, and PPAR-γ, Cyclin D1 mRNA was measured quantitatively by reverse transcription-polymerase chain reaction （RT-PCR）. The expression of PPAR-γ, protein was measured quantitatively by Western blot, and the expression of Cyclin D1 protein in gastric cancer cells was detected by immunohistochemistry. RESULTS： Res inhibited the proliferation of SGC-7901 cells in a dose- and time-dependent manner （P 〈 0.05）, and flow cytometry analysis revealed that the cell cycle was blocked at G1- phase. RT-PCR and Western blot showed that both PPAR-γ mRNA and protein were expressed in SGC-7901 cells, and Res enhanced PPAR-γ mRNA expression. After SGC-7901 cells were treated by Res with the concentration of 25, 50, 75 and 100 μmol/L, the relative percentages of PPAR-γ mRNA expression were 122.2%, 195.1%, 232.9% and 277.1% of those in the controls （P 〈 0.05）, but the expression of PPAR-γ protein didn＇t changed. The high levels of Cyclin D1 mRNA and protein expression were detected in SGC-7901 cells, while Res significantly decreased the expression of Cyclin D1. After SGC-7901 cells were treated by Res with the concentration of 25, 50, 75 and 100μmol/L, the inhibitory rates of Cyclin D1 mRNA were 11.3%, 24.3%, 35.4% and 59.5%, respectively, while GW9662 markedly decreased the above effects of Res. CONCLUSION： Res can significantly inhibit Cyclin D1 expression partly by activating PPAR-γ in gastric cancer cells SGC-7901, which results in the blockage of cell cycle at G1 phase and inhibition of cell proliferation.