EGFR Activation in H. Pylori-Induced Gastric Cancer

H. Py/或Py/诱导的胃癌发生与胃上皮细胞凋亡的失调有关， 然而，控制这些细胞反应的机制尚不清楚。H.幽门螺杆菌诱导胃 表皮生长因子受体（EGFR）和下游靶点ERK 1/2的上皮细胞活化。 这些信号通路调节与肿瘤发生有关的细胞增殖和存活程序， 其他系统和我们的数据现在表明，H。pylori激活EGFR减弱细胞凋亡。我们 初步的研究结果也表明，解整合素和金属蛋白酶-（ADAM-）17的表达是必需的 对于H. pylori，EGFR的激活介导H. py/ori诱导的氧化应激 通过上调精胺氧化酶（SMO）。因此，我们假设EGFR的反式激活 是H. py/ori介导的肿瘤发生，启动 抗凋亡反应，提高了由这种病原体诱变的细胞的保留。 为实现这一目标，我们有三个具体目标：1.确定激活的机制 EGFR与H.幽门。我们将专注于亚当的要求- 图17使用ADAM-17敲除和加回细胞系和特异性抑制剂进行EGFR活化。EGFR 相互作用的蛋白质将用Flag-EGFR沉淀并通过MALDI-TOF分析鉴定。2.定义 EGFR反式激活的贡献，并确定H. Py/or/-介导的胃 上皮细胞DNA损伤。我们将评估SMO作为EGFR下游靶点的作用， 反式激活，确定氧化损伤和DMA损伤，并使用2D-DIGE鉴定下游 H的目标。Py/或i-介导的EGFR反式激活。3.确定EGFR反式激活对 H. py/or/-介导的胃上皮细胞DMA损伤、凋亡、增殖和肿瘤发生 vivo.增殖、凋亡、应激反应和癌前病变将在H.幽门感染 野生型和EGFR缺陷型小鼠。本研究的意义在于确定 H. Py/or/-介导的胃上皮细胞在诱变背景下的存活 途径导致胃肿瘤的发生，这是重要的，确定新的治疗目标H。 Py/ori介导的疾病。此外，这些机制可能与许多炎症相关， 由细胞增殖和凋亡程序改变引起的肠道疾病。

H. py/or/-induced gastric tumorigenesis is associated with dysregulation of gastric epithelial apoptosis and aroliferation; yet, the mechanisms that govern these cellular responses are unclear. H. pylori induces gastric epithelial cell activation of epidermal growth factor receptor (EGFR) and a downstream target, ERK1/2. These signaling pathways regulate cellular proliferation and survival programs implicated in tumorigenesis in other systems and our data now indicate that H. pylori activation of EGFR attenuates apoptosis. Our preliminary findings also show that a disintegrin and metalloproteinase- (ADAM-) 17 expression is required for EGFR transactivation by H. pylori and that activation of EGFR mediates H. py/ori-induced oxidative stress through up-regulation of spermine oxidase (SMO). Therefore, we hypothesize that transactivation of EGFR is a key molecular regulatory step in the pathogenesis of H. py/ori-mediated tumorigenesis, initiating anti-apoptotic responses that heighten the retention of cells mutagenized by this pathogen. Three Specific Aims are designed to achieve this goal: 1. Determine the mechanism of activation of EGFR and the molecular interactions regulated by H. pylori. We will focus on the requirement of ADAM- 17 for EGFR activation using ADAM-17 knockout and add-back cell lines and specific inhibitors. EGFR interacting proteins will be precipitated with Flag-EGFR and identified by MALDI-TOF analysis. 2. Define the contribution of EGFR transactivation and identify downstream targets in H. py/or/-mediated gastric epithelial cell DMA damage. We will assess the role of SMO as a downstream target of EGFR transactivation, determine oxidative injury and DMA damage, and use 2D-DIGE to identify downstream targets of H. py/or/'-mediated EGFR transactivation. 3. Determine the effects of EGFR transactivation on H. py/or/-mediated gastric epithelial cell DMA damage, apoptosis, proliferation, and tumorigenesis in vivo. Proliferation, apoptosis, stress responses, and cancer precursor lesions will be analyzed in H. pyloriinfected wild-type and EGFR-defective mice. The significance of this research is to determine the molecular mechanism(s) of H. py/or/-mediated gastric epithelial cell survival within the context of mutagenesis pathways leading to gastric tumorigenesis, which is important for identifying novel therapeutic targets for H. py/ori-mediated diseases. Furthermore, these mechanisms may be implicated in a number of inflammationassociated intestinal disorders resulting from altered programs of cellular proliferation and apoptosis.