PD98059抑制MAPK/ERK信号通路对胃癌细胞生物学功能的影响

目的：研究MAPK/ERK信号通路中关键信号分子MEK和ERK在胃癌SGC-7901细胞中的表达及PD98059抑制MAPK/ERK通路对胃癌细胞生物学功能的影响。方法：体外培养胃癌细胞株SGC-7901，不同浓度（0、25、50、100、200、300和400 mmol/L）PD98059处理24 h后CCK-8法检测细胞增殖率变化；再用0、25、50和100 μmol/L PD98059处理24 h后采用实时荧光定量PCR（qPCR）检测MEK和ERK mRNA的表达量；Western blot检测MEK和ERK蛋白的表达；流式细胞术检测细胞周期和凋亡变化。同时设正常胃黏膜上皮GES-1细胞为对照。结果：与正常胃黏膜上皮GES-1细胞相比，胃癌SGC-7901细胞中MEK和ERK mRNA的表达升高，差异具有统计学意义（P < 0.05）；p-MEK、p-ERK蛋白的表达亦显著升高，差异具有统计学意义（P < 0.05）。0~200 μmol/L PD98059处理SGC-7901细胞后，细胞增殖率随着抑制剂浓度的升高而降低（P < 0.05）。当PD98059浓度处于200~400 μmol/L时抑制作用逐渐趋于平稳。0~100 μmol/L PD98059作用后MEK、ERK mRNA的表达量低于对照组（P < 0.05），随着PD98059浓度升高，ERK mRNA表达量逐渐降低（P < 0.05）。Western blot检测结果显示50和100 μmol/L PD98059作用后p-MEK1/2、p-ERK1/2蛋白表达降低（P < 0.05）。且抑制剂PD98059使胃癌SGC-7901细胞发生G0/G1期阻滞，可诱导细胞凋亡。结论：MAPK/ERK信号通路在胃癌细胞中激活，PD98059通过抑制MAPK/ERK信号通路的活性可影响胃癌细胞的生物学功能。

Inhibitory effects of PD98059 on the MAPK/ERK signaling pathway in gastric cancer cells

OBJECTIVE:To investigate expression of key signaling molecules MEK and ERK in the MAPK/ERK signaling pathway and effect of PD98059 on MAPK/ERK pathway's biological function in the gastric cancer SGC-7901 cells. METHODS:Gastric cancer cell line SGC-7901 was cultured in vitro. Cell proliferation rates were detected by the CCK-8 method after treatment with different concentrations of PD98059 at 0,25,50,100,200,300 and 400 μmol/L for 24 h. Expression of MEK and ERK mRNA was detected by real-time quantitative PCR (qPCR) after treatment with 0,25,50 and 100 μmol/L PD98059 for 24 h. Expression of MEK and ERK proteins was detected by Western blot. Cell cycle and apoptosis were detected by flow cytometry. The normal gastric mucosal epithelial GES-1 cells were used as controls. RESULTS:Compared with the normal cells,expression of MEK and ERK mRNA and p-MEK and p-ERK proteins in the gastric cancer cells was significantly increased (P < 0.05). After treatment with PD98059,the cell proliferation rates were decreased with increasing concentration and in a dose-dependent manner. When the concentration of PD98059 was between 200 and 400 μmol/L,the inhibition became stabilized. Expression of the MEK and ERK mRNA was lower than that of the control group after treatment with 0-100 μmol/L PD98059 (P < 0.05). With increasing concentrations of PD98059,expression of ERK mRNA was gradually reduced (P < 0.05). Western blot analyses show that expression of p-MEK1/2 and p-ERK1/2 protein decreased after treatment with 50 and 100 μmol/L PD98059 (P < 0.05). Moreover,PD98059 caused G0/G1 phase arrest and induced apoptosis. CONCLUSION:MAPK/ERK signaling pathway was active in the gastric cancer cells. PD98059 inhibited activities in the MAPK/ERK signaling pathway and affected the biological function of the gastric cancer cells.