hOGG1低表达肿瘤细胞对阿霉素的敏感性研究

Study on Sensitivity to Adriamycin of Down-regulated Cells Expressed hOGG1 Gene which Target to Oxidative DNA Damage and Repair

目的研究8-羟基鸟嘌呤DNA糖苷酶1基因(hOGG 1)低表达细胞对阿霉素的敏感性,为化疗增敏提供实验依据。方法用不同剂量的阿霉素处理肺腺癌A 549细胞和通过稳定转染hOGG 1核酶而获得的hOGG 1低表达的A 549-R细胞,用M TT法测定两种细胞的存活率;体外微核试验及单细胞凝胶电泳检测两种细胞微核率及DNA损伤与修复的差异;流式细胞术检测周期分布、凋亡率和细胞增殖指数。结果A 549-R细胞阿霉素半数抑制浓度(IC50)低于A 549细胞(P<0.05);阿霉素可诱导两种细胞的微核率增高,而在相同阿霉素剂量作用下A 549-R细胞微核率较A 549细胞更高(P<0.05);单细胞凝胶电泳结果显示阿霉素作用下两种细胞均有不同程度DNA损伤,A 549-R细胞的拖尾率和DNA迁移长度大于A 549细胞(P<0.05);与A 549细胞比较,A 549-R细胞更不易修复。流式细胞术检测显示:阿霉素处理使两种细胞都表现为G0/G1期细胞阻滞,细胞凋亡随阿霉素浓度增加而增加,细胞增殖指数随阿霉素浓度增加而降低,这些变化均以A 549-R细胞更为明显。结论hOGG 1低表达使细胞DNA修复能力降低,从而使细胞对阿霉素的敏感性增强。

Objective To investigate the sensitivity to Adriamyein of down-regulated cells expressed hOGG1 gene which target to oxidative DNA damage and repair,and provide more experimental evidence of sensitizing the response of tumor to chemotherapy. Methods Human lung adenoeareinoma A549 cells and A549-R cells transfeeted with a ribozyme gene which inhibited the hOGG1 mRNA expression were studied. The viability of cells treated with Adriamyein at different dosage was detected by MTT test. Mieronueleus rate, DNA damage and repair were detected by mieronueleus test in vitro and single cell gel eleetrophoresis assay （SCGE） ; Apoptotie cell population, cell cycle distribution and cell proliferation index of the two kind of cells were determined by flow eytometry. Results The cell viability after treatment with Adriamyein was significantly lower in A549-R cells than in A549 cells （P〈0. 05）. The mieronueleus rate in A549-R cells was higher than A549 cells statistically （P〈0. 05）. DNA damage of A549-R cells induced by Adriamyein at different dosage was more serious than A549 cells both in comet cell rate and DNA migration length. The DNA repair after treatment of Adriamyein happened late in both kinds of cells but had a big difference in the repair capability of the two kinds of cells. The repair capability in A549-R cells was significantly lower than that of A549 cells. The percentages of A549-R cells in G0/G1 phase were increased after treatment with Adriamyein. Additionally, the apoptosis percentages of cells were significantly increased in the two kinds of cells, and the cell proliferation index was decreased with the increase of Adriamyein dosage. These changes in A549-R cells were demonstrated more obviously than that of A549 cells. Conclusion Down-regulating of the expression of hOGG1 can decrease the DNA repair capability of A549 cells, and increase the sensitivity of cells to Adriamyein.