DNA损伤修复酶hOGG1降低食管鳞癌细胞对H2O2和顺铂的敏感性

目的 观察食管鳞状上皮癌( ESCC)细胞中,DNA损伤修复酶人8-羟基鸟嘌呤DNA糖苷酶( hOGG1)的高表达,对该细胞H2O2氧化剂和化疗药物顺铂(DDP)敏感性的影响。方法 构建重组腺病毒pAd-CMV5-DEST-hOGG1,并转染食管鳞癌细胞,建立高表达hOGG1的食管鳞癌细胞( EC9706-hOGG1)模型。H2O2和顺铂分别作用于转染重组腺病毒的EC9706细胞、转染空腺病毒EC9706细胞(EC9706-LACZ)以及未转染病毒EC9706( EC9706)细胞。用噻唑蓝(MTT)比色法和锥虫蓝染色法比较3种细胞的存活率,用8-羟基鸟嘌呤(8-oxoG)免疫组织化学比较3种细胞的氧化损伤程度,用TUNEL法和流式细胞仪(FCM)检测法比较3种细胞的凋亡。结果 高表达hOGG1的食管鳞癌细胞较两对照组细胞有更高的存活率、更低的8-oxoG氧化损伤程度和凋亡指数。用1000μmol/L H2O2作用1.5h后,用流式细胞仪检测,发现EC9706-hOGG1细胞较EC9706-LACZ及EC9706细胞凋亡减少。凋亡率为EC9706-hOGG1:5.50％,EC9706-LACZ:12.54％,EC9706:13.48％。用10 mg/L DDP作用1.5h后,发现EC9706-hOGG1细胞较EC9706-LACZ及EC9706细胞凋亡减少。凋亡率分别为EC9706-hOGGl:3.95％,EC9706-LACZ:11.59％,EC9706:11.48％。结论 食管鳞癌细胞中hOGG1蛋白高表达,可能会导致食管鳞癌细胞对氧化剂H2O2和化疗药物顺铂耐受。

Reduction of H2O2 and DDP sensitivity of ESCC cells by high-level expression of DNA repair enzyme hOGG1

Objective To explore the effect of high-level expression of DNA repair enzyme human 8-oxoguanine DNA glycosylase (hOGG1) on H2O2 and cisplatin (DDP) sensitivity of esophageal squamous cell carcinoma (ESCC) EC9706 cells. Methods Recombinant adenovirus pAd-CMV5-DEST-hOGG1 was transferred into EC 9706 cells to establish the EC9706 cell model with high-level expression of hOGG1 protein. EC9706 cells infected with the recombinant adenovirus (EC9706-hOGG1) or adenovirus vector (EC9706-LACZ), or non-transfected EC9706 cells (EC9706) were acted by H2O2 and DDP, respectively. The survival rate of the three kinds of cells was compared by using methyl thiazol tetrazolium (MTT) and trypan blue experiments. The comparison of the oxidative damage of the three kinds of ceils was performed by using 8-oxoG immunohistochemistry. The apoptosis index were assayed by the TUNEL staining and flow cytometry (FCM). Results The higher survival rate and the lower 8-oxoG oxidative damage and the lower apoptosis index of the EC9706 cells with high-lever high hOGGlexpression were than ones of the two control groups;Detected by FCM,after 1000 μmol/L H2O2 inducing apoptosis 1.5 hour, cell apoptosis rate of EC9706-hOGG1 ( 5.50％ ) was downregulated markedly than EC9706-LACZ ( 12. 54％ ) and EC9706 cells (13.48％). After three groups treat with 10 mg/L DDP 1.5 h,the apoptois rate in groups EC9706-hOGG1 ,EC9706-LACZ and EC9706 was 3.95％, 11.59％ and 11.48％. There was significant difference between group EC9706-hOGG1 and other control groups. Conclusion The high-level expression of hOGG1 protein of EC 9706 cells may reduce H2O2 and cisplatin sensitivity to EC 9706 cells.