摘要目的:探讨GNG4与卵巢癌顺铂耐药A2780/DDP细胞DNA损伤修复及化疗敏感性的关系。方法:将A2780/DDP细胞分为500 ng/ml顺铂作用组（cDDP组）、短发夹RNA（shRNA）-GNG4沉默GNG4表达组（shRNA组）、500 ng/ml顺铂和shRNA-GNG4干预组（shRNA+cDDP组）、未经顺铂和shRNA-GNG4干预组（空白对照组）。采用蛋白质印迹法检测各组细胞GNG4和γH2AX蛋白的表达，单细胞凝胶电泳法检测各组细胞DNA损伤情况，免疫荧光法检测γH2AX基因在损伤位点的焦点形成情况，平板克隆形成实验检测细胞克隆形成能力。结果:与其他3组相比，shRNA+cDDP组GNG4蛋白表达水平最低，γH2AX蛋白表达水平最高，差异均有统计学意义（均 P<0.01）。单细胞凝胶电泳法检测显示，空白对照组、cDDP组、shRNA组、shRNA+cDDP组细胞彗星尾DNA百分含量分别为（7.7±2.5）%、（12.3±3.6）%、（20.1±2.1）%、（38.6±2.8）%，Olive尾距分别为5.12±1.89、8.23±2.97、14.99±3.65、22.43±3.17，shRNA+cDDP组细胞彗星尾DNA含量和Olive尾距均高于其他3组，差异均有统计学意义（均 P<0.05）。免疫荧光法检测显示，空白对照组、cDDP组、shRNA组、shRNA+cDDP组每个细胞中γH2AX的焦点数分别为（4.2±0.7）个、（5.1±0.5）个、（26.8±3.3）个、（71.3±6.2）个，shRNA+cDDP组均高于其他3组，差异均有统计学意义（均 P<0.05）。空白对照组、cDDP组、shRNA组、shRNA+cDDP组克隆形成率分别为（78.27±5.01）%、（45.67±3.29）%、（26.20±5.76）%、（1.56±0.21）%，shRNA+cDDP组均低于其他3组，差异均有统计学意义（均 P<0.001）。 结论:下调GNG4的表达可增加卵巢癌A2780/DDP细胞对顺铂的敏感性，其可能是通过抑制顺铂诱导的DNA损伤修复功能实现的。

abstractsObjective:To investigate the correlation of GNG4 with DNA damage repair and chemosensitivity of ovarian cancer cisplatin-resistant A2780/DDP cells.Methods:A2780/DDP cells were divided into 500 ng/ml cisplatin group (cDDP group), short hairpin RNA (shRNA)-GNG4 silencing GNG4 expression group (shRNA group), 500 ng/ml cisplatin and shRNA-GNG4 intervention group (shRNA+cDDP group), and non cisplatin and shRNA-GNG4 intervention group (blank control group). Western blot was used to detect the expressions of GNG4 and γH2AX proteins in each group; DNA damage in each group was detected by single cell gel electrophoresis. The focus formation of γH2AX gene at the injury site was detected by immunofluorescence. The ability of cell clone formation was detected by plate clone formation experiment.Results:Compared with the other three groups, the expression level of GNG4 protein in shRNA+cDDP group was the lowest, the expression level of γH2AX protein was the highest, and the differences were statistically significant (all P < 0.01). Single cell gel electrophoresis assay showed that the comet tail DNA% in blank control group, cDDP group, shRNA group and shRNA+cDDP group were (7.7±2.5)%, (12.3±3.6)%, (20.1±2.1)%, (38.6±2.8)%, respectively, and Olive trailing distance were 5.12±1.89, 8.23±2.97, 14.99±3.65, 22.43±3.17, respectively, the comet tail DNA% and Olive tail distance in shRNA+cDDP group were higher than those in the other three groups, and the differences were statistically significant (all P < 0.05). Immunofluorescence assay showed that the focus numbers of γH2AX in each cell of blank control group, cDDP group, shRNA group and shRNA+cDDP group were 4.2±0.7, 5.1±0.5, 26.8±3.3, 71.3±6.2, respectively, the shRNA+cDDP group was higher than the other three groups, and the differences were statistically significant (all P < 0.05). The clone formation rates of blank control group, cDDP group, shRNA group and shRNA+cDDP group were (78.27±5.01)%, (45.67±3.29)%, (26.20±5.76)%, (1.56±0.21)%, respectively, the shRNA+cDDP group was lower than the other three groups, and the differences were statistically significant (all P < 0.001). Conclusions:Down-regulation of GNG4 expression can increase the cisplatin sensitivity of ovarian cancer A2780/DDP cells, which may be achieved by inhibiting the DNA damage repair function induced by cisplatin.