干扰PARP-1基因对人胃癌HGC-27细胞增殖、凋亡及放射敏感性的影响

Effects of PARP-1 gene interference on proliferation,apoptosis and radiotherapy sensitivity of human gastric cancer HGC-27 cells

目的:探讨干扰多聚腺苷二磷酸核糖聚合酶-1(PARP-1)基因对人胃癌HGC-27细胞增殖、凋亡及放射敏感性的影响。方法:采用qRT-PCR检测人正常胃黏膜上皮细胞GES-1及人胃癌细胞MKN-45、MGC-803、SGC-7901、AGS、HGC-27中PARP-1 mRNA的表达。取HGC-27细胞分为3组,si-PARP-1组和阴性对照组采用脂质体法分别转染特异性PARP-1 siRNA和si-NC,空白对照组不转染。采用qRT-PCR和Western blot法检测上述3组HGC-27细胞中PARP-1 mRNA和蛋白的表达,CCK-8法检测细胞增殖能力,Annexin-Ⅴ/PI双染法检测细胞凋亡,Western blot法检测细胞中Caspase-3和Caspase-8蛋白的表达,同时用克隆形成实验检测细胞的放射敏感性。结果:胃癌细胞中PARP-1 mRNA的表达水平均高于GES-1细胞(P<0.05),且HGC-27细胞中的表达水平最高。与阴性对照组和空白对照组相比,si-PARP-1组HGC-27细胞中PARP-1的表达下调,细胞增殖受抑,细胞凋亡率升高,Caspase-3和Caspase-8蛋白表达水平升高,X射线照射后si-PARP-1组细胞克隆形成数减少(P<0.05)。结论:干扰PARP-1基因可抑制胃癌HGC-27细胞增殖,促进细胞凋亡,增强细胞的放射敏感性,其机制可能与Caspase-8/Caspase-3途径有关。

Aim:To investigate the effects of interfering PARP-1 gene on proliferation,apoptosis and radiosensitivity of human gastric cancer HGC-27 cells.Methods:qRT-PCR was used to detect the expression of PARP-1 mRNA in human normal gastric mucosal epithelial cells GES-1 and different human gastric cancer cells MKN-45,MGC-803,SGC-7901,AGS and HGC-27.HGC-27 cells were transfected by specific PARP-1 siRNA by liposome method(PARP-1 siRNA group),and the negative control group transfected with PARP-1 si-NC(si-NC group)and the blank control group were set.The expression of PARP-1 in HGC-27 cells was detected by qRT-PCR and Western blot.The cell proliferation ability was measured by the CCK-8 method.Cell apoptosis was detected by Annexin-V/PI double staining method.The expressions of Caspase-3 and Caspase-8 were detected by Western blot.Clonal formation assay was adopted to detect cell sensitivity to radioactivity.Results:The expression of PARP-1 mRNA in gastric cancer cells was significantly higher than that in normal gastric mucosal epithelial cells GES-1(P<0.05),and it was the highest in HGC-27 cells.Compared with the si-NC group and blank control group,the expression of PARP-1 in HGC-27 cells was significantly down-regulated,cell proliferation was inhibited,cell apoptosis rate increased,and Caspase-3 and Caspase-8 protein expressions were up-regulated(P<0.05).Besides,the number of clones in the PARP-1 siRNA group was significantly less than those in the si-NC group and blank control group after X-ray irradiation(P<0.05).Conclusion:Interfering PARP-1 gene can inhibit the proliferation of gastric cancer HGC-27 cells,promote cell apoptosis and increase cell sensitivity to radiation.The mechanism of PARP-1 affecting the radiosensitivity of gastric cancer cells may be related to the Caspase-8/Caspase-3 pathway.