miR-650靶向PRDX2调控幽门螺旋杆菌对胃癌细胞氧化应激的机制研究

背景与目的：幽门螺旋杆菌（HP）在人类胃部的定植是引起胃癌发生较明确的危险因素，且研究发现，HP感染后胃癌细胞的氧化应激水平有明显改变，但机制尚未明确。因此，本研究探讨HP引起胃癌细胞氧化应激的潜在机制和作用。方法：用HP感染胃癌细胞SNU-1后，分别用DCF-DA荧光法和CCK-8法检测的活性氧（ROS）水平和增殖能力的变化；用高通量测序和siRNA筛选鉴定HP感染后引起SNU-1细胞氧化应激增强的关键基因，随后通过miRDB在线分析和荧光素酶报告系统鉴定引起胃癌细胞SNU-1氧化应激的关键上游miRNA，同时结合功能获得与功能缺失实验验证。结果：SNU-1细胞感染HP后，ROS水平升高，增殖能力增强，但同时使用氧化应激抑制剂乙酰半胱氨酸处理，SNU-1细胞的以上变化被取消（均P>0.05）。siRNA筛选结果发现，敲低过氧化氢酶2(PRDX2)时HP感染的SNU-1细胞ROS水平升高，增殖能力增强，而过表达PRDX2后则相反（均P<0.05），同时Western blot验证显示，HP感染后SNU-1细胞中PRDX2的表达下调。HP感染后，SNU-1细胞中PRDX2的启...

Mechanism of miR-650 targeting PRDX2 to regulate oxidative stress in gastric cancer cells with Helicobacter pylori infection

Background and Aims The colonization of Helicobacter pylori (HP) in the human stomach is a recognized risk factor for the occurrence of gastric cancer. Study also found that the oxidative stress is significantly changed in gastric cancer cells after HP infection, while the mechanism is not entirely elucidated. Therefore, this study was conducted to investigate the potential mechanism and role of HP-induced oxidative stress in gastric cancer cells.Methods In gastric cancer SNU-1 cells after HP infection, the changes in production of reactive oxygen species (ROS) and proliferation ability were detected by DCF-DA fluorescence and CCK-8 assay. The key genes inducing oxidative stress in SNU-1 cells after HP infection were identified by high-throughput sequencing and siRNA screening, and then the key upstream miRNAs causing oxidative stress in SNU-1 cells were identified using miRDB online analysis tools and luciferase reporter assay, in combination with gain- and loss-of-function experiments for validation.Results In SNU-1 cells after HP infection, the ROS level was increased and the proliferation ability was enhanced, but these changes were abolished by simultaneous treatment with the ROS inhibitor acetylcysteine (all P>0.05). The results of siRNA screening found that the ROS level was increased and the proliferation ability was enhanced in SNU-1 cells with HP infection after peroxiredoxin 2 (PRDX2) knock-down and the opposite changes were found after PRDX2 overexpression (all P<0.05). Meanwhile, Western blot validation showed that PRDX2 was down-regulated in SNU-1 cells after HP infection. The promoter activity of PRDX2 in SNU-1 cells did not change after HP infection (P>0.05), but the mRNA level of PRDX2 was decreased (P<0.05). Results of analysis showed that the expression level of miR-650 in SNU-1 cells with HP infection was increased (P<0.05), and miR-650 targeted at the 3'' non-coding region of the PRDX2 mRNA. Results of validation showed that the PRDX2 expression was down-regulated, the ROS level was increased and the proliferation ability was enhanced in SNU-1 cells after overexpression of miR-650, and the opposite changes were seen after miR-650 knockdown (all P<0.05); the proliferation ability had no significant change in SNU-1 cells with HP infection and simultaneous miR-650 knockdown or simultaneous PRDX2 overexpression (both P>0.05).Conclusion The mechanism and action of HP infection in gastric cancer cells is possibly that it up-relates the expression of miR-650, and the latter suppresses the mRNA and protein expressions of PRDX2 by binding its 3'' non-coding region, and then causes the increase of ROS level, thereby promotes the proliferation of gastric cancer cells.