Helicobacter pylori CagA inhibits the expression of Runx3 via Src/MEK/ERK and p38 MAPK pathways in gastric epithelial cell
Helicobacter pylori CagA inhibits the expression of Runx3 via Src/MEK/ERK and p38 MAPK pathways in gastric epithelial cell
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幽门螺杆菌 CagA 通过 Src/MEK/ERK 和 p38 MAPK 通路抑制胃上皮细胞 Runx3 的表达
DOI：
10.1002/jcb.23440
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发表时间：
2012-03-01
影响因子：
4
通讯作者：
Jia, Jihui
中科院分区：
文献类型：
--
作者：
Liu, Zhifang;Xu, Xia;Jia, Jihui
CagA阳性幽门螺杆菌感染是胃癌最强的危险因素。在递送到胃上皮细胞中后，CagA通过酪氨酸磷酸化依赖性和非依赖性机制与细胞内信号传导分子物理相互作用并解除调节来干扰细胞功能。Runx 3可能是一种抑癌基因，与胃癌的发生、发展密切相关。本研究的目的是验证H. pylori毒力因子CagA对Runx 3表达水平的影响，探讨影响Runx 3表达的分子机制和信号通路。用FuGENE HD转染试剂将CagA表达载体或对照载体转染人胃上皮永生化GES-1细胞。通过QRT-PCR和免疫印迹测定Runx 3表达水平。然后我们建造了一个1,150？bp Runx 3启动子荧光素酶报告质粒pGL 3 -1150？bp，与CagA表达载体或对照载体共转染GES-1细胞。荧光素酶报告基因检测用于确定CagA对1，150？bp的Runx 3启动子活性。使用信号抑制剂来检测CagA通过其影响Runx 3的信号途径。结果表明，CagA能显著降低Runx 3在mRNA和蛋白水平的表达。重要的是，1,150？与用对照载体转染的细胞相比，用CagA表达载体转染的细胞中bp Runx 3启动子活性降低。这种抑制作用依赖于CagA的磷酸化。信号通路Src/MEK/ERK和p38 MAPK参与了这一调节。我们的发现为理解H.幽门癌发生J.细胞。113：10801086，2012. (C)2011 Wiley Periodicals，Inc.
Infection with CagA-positive Helicobacter pylori is the strongest risk factor for gastric carcinoma. Upon delivery into gastric epithelial cells, CagA disturbs cellular functions by physically interacting with and deregulating intracellular signaling molecules via both tyrosine phosphorylation-dependent and -independent mechanisms. Runx3 was suggested to be a tumor suppressor and closely associated with tumorigenesis and progression of gastric cancer. The aim of our study is to verify the effect of H. pylori virulence factor CagA on Runx3 expression level and investigate the corresponding molecular mechanisms and signaling pathways influencing Runx3 expression. Human gastric epithelial immortalized GES-1 cells were transfected with CagA-expression vector or control vector with FuGENE HD transfection reagent. Runx3 expression levels were determined by QRT-PCR and immunoblotting. Then we constructed a 1,150?bp Runx3 promoter luciferase reporter plasmid, pGL3-1150?bp, which was co-transfected into GES-1 cell with CagA-expression vector or control vector. Luciferase reporter assay was used to determine the effects of CagA on the 1,150?bp promoter activity of Runx3. Signal inhibitors were used to detect the signal pathway(s) through which CagA affects Runx3. Our results showed that CagA can reduce the expression level of Runx3 at both mRNA and protein levels significantly. Importantly, the 1,150?bp Runx3 promoter activity was decreased in cells transfected with CagA-expression vector comparing with cells transfected with control vector. And this inhibition is dependent on the phosphorylation of CagA. Signal pathways Src/MEK/ERK and p38 MAPK are involved in this regulation. Our findings provide new insights for understanding the mechanism of H. pylori carcinogenesis. J. Cell. Biochem. 113: 10801086, 2012. (C) 2011 Wiley Periodicals, Inc.