细胞毒力因子CagA上调人胃黏膜上皮GES-1细胞TET2蛋白的表达  

Virulence factor CagA upregulates TET2 protein expression in human gastric mucosa epithelial GES-1 cells

作　　者：张昕[1] 付华林[1] 郅晓[1] 金卫林[1] 崔大祥[1] 

机构地区：[1]上海交通大学微纳科学技术研究院生物纳米工程研究室微纳制造技术国家重点实验室薄膜与微细技术教育部重点实验室,上海200240

出　　处：《中国肿瘤生物治疗杂志》2013年第2期153-158,共6页Chinese Journal of Cancer Biotherapy

基　　金：国家重点基础研究发展计划(973计划)资助项目(No.2010CB933901);国家杰出青年基金资助项目(No.81225010)~~

摘　　要：目的:探讨幽门螺旋杆菌细胞毒素相关基因A(cytotoxin associated gene A,CagA)与胃黏膜中TET2(ten-eleventranslocation 2)蛋白表达的关系,以及TET2在CagA致癌过程中可能的作用。方法:Real-time PCR检测人胃黏膜上皮细胞株GES-1和胃癌细胞株MGC-803中TET2 mRNA的表达水平,细胞免疫染色法检测TET2蛋白的细胞定位及表达。将pEGFP-CagA通过脂质体介导转染GES-1细胞,用200μmol/L H2O2处理GES-1细胞建立氧化应激模型,流式细胞仪检测细胞中活性氧(reactive oxygen species,ROS)和细胞周期的变化。结果:TET2 mRNA在GES-1细胞的表达水平低于胃癌MGC-803细胞(1.00±0.08 vs 1.68±0.07,P<0.05),TET2蛋白在GES-1细胞表达水平低于胃癌MGC-803细胞(8.09±3.57 vs14.60±2.31,P<0.05)。与阴性对照组pEGFP-N1相比,pEGFP-CagA转染组GES-1细胞中TET2 mRNA表达水平升高(1.00±0.04 vs 0.06±0.00,P<0.05),TET2蛋白表达水平也升高(16.45±4.40 vs 10.82±3.39,P<0.05),ROS积累水平升高(18.39±4.52 vs 15.31±4.40,P<0.05),细胞周期检测出现明显的凋亡峰。氧化应激(H2O2处理)模型中GES-1细胞与空白对照GES-1细胞相比,TET2 mRNA水平升高(1.44±0.02 vs 1.00±0.04,P<0.05),TET2蛋白表达水平增高(15.72±4.52vs 11.74±4.34,P<0.05)。结论:幽门螺旋杆菌毒力因子CagA可诱导GES-1细胞ROS增高和细胞周期的失衡,氧化应激可以诱导TET2表达上调,TET2可能参与CagA的致癌过程。Objective： To investigate the association between the expression of the ten-eleven translocation 2 （TET2） protein and the cytotoxin associated gene A （CagA） of Helicobacter pylori （ Hp）, and to explore the possible mechanisms of CagA in the process of gastric carcinogenesis. Methods： Real-time PCR was used to detect TET2 mRNA level in hu- man gastric epithelial GES-1 cells and gastric cancer MGC-803 cells. Immuncytochemistry was used to detect the TET2 protein localization and expression in GES-1 and MGC-803 cells. GES-1 cells were transfected with pEGFP-CagA and a cell oxidative stress model was constructed with 200 μmol/L H202. Flow cytometry was used to analyze cell cycle and ROS in GES-1 cells. Results： The mean expression level of TET2 mRNA in GES-1 ceils was lower than that in MGC-803 cells （ 1.00 ± 0.08 vs 1.68 ± 0.07, P 〈 0.05 ）. TET2 protein expression in GES-1 cells was lower than that in MGC-803 cells （8.09 ± 3.57 vs 14.60 ± 2.31 ,P 〈 0.05）. Compared with the negative control pEGFP-N1 group, the mean expres- sion level of TET2 mRNA in pEGFP-CagA-transfected GES-1 cells was increased （ 1.00 ± 0.04 vs O. 06 ±0. 00, P 〈0. 05 ）, and TET2 protein expression in pEGFP-CagA-transfected GES-1 cells was also increased （ 10.82 ＋ 3.39 vs 16.45 ± 4.40 ,P 〈 0.05 ）, and a higher level of ROS production was observed in pEGFP-CagA-transfected GES-1 cells （69 ＋ 9.0 vs 91 ± 16.8 ,P 〈0.05）, which significantly displayed the cell apoptosis in cycle analysis. In the cell oxidative stress model, TET2 mRNA level in H202 treated cells was higher than that in normal GES-1 cells （1.44 ±0.02 vs 1.00 ±0.0g, P 〈0. 05 ） and TET2 protein expression level was higher than that in normal GES-1 cells （ 11.74 ＋4.34 vs 15.72 ＋g. 52, P 〈 0.05 ）. Conclusion： CagA factor can induce ROS accumulation and cell cycle disruption of GES-1, indicating that TET2 can be upregulated by oxidative stress and may be involved in the progress of CagA-induced carcinogenesis.

关 键 词：细胞毒素相关基因A(CagA) 幽门螺旋杆菌 TET2蛋白 胃癌 MGC-803细胞株 GES-1细胞株 活性氧 

分 类 号：R735.2[医药卫生—肿瘤] R730.2[医药卫生—临床医学]