Effects of GNG4 on DNA damage repair and chemosensitivity of ovarian cancer cisplatin-resistant A2780/DDP cells / 肿瘤研究与临床

ABSTRACT

Objective: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.