2009-08-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/714056摘要：幽門桿菌是第一個被正式認定為細菌類的致癌物。它利用本身的 type-IV 分泌系統將癌症相關蛋白質CagA送入寄主細胞，並刺激IL-8的表現，進而使寄主細胞增長。我們初步的研究結果發現，annexin A4在胃癌病人的組織及被幽門桿菌感染的寄主細胞中表現量增加，而且幽門桿菌感染後會刺激寄主細胞表現 IL-8，但 IL-8 的表現也會被 annexin A4 的 siRNA 所抑制。幽門桿菌 type-IV 分泌系統感染細胞，進而誘導c-Jun活化的相關研究已很清楚，但是c-Jun如何活化下游基因，因而刺激IL-8的表現仍待進一步探討，於是促使我們探究annexin A4是否在這過程中扮演很重要的調控角色？ 這個計畫的主要目的是要解析幽門桿菌感染後annexin A4相關的基因網路、訊息及調控機制。本計畫將透過與美國洛杉磯加州大學Dr. James C. Liao的國際合作，來鑑定受影響的轉錄因子和路徑，進而分辨多重轉錄因子的效用。了解幽門桿菌感染寄主細胞的重要訊息路徑將提供我們洞悉幽門桿菌造成癌化的分子基礎並找到具潛力的標靶以治療胃癌。本計畫的特定目標如下： 1. 了解幽門桿菌感染後寄主細胞內annexin A4上游基因的調節角色。 2. 建構annexin A4下游的基因網路及鑑定參與反應的轉錄因子和路徑。 本計畫的研究成果可以讓我們更加了解幽門桿菌感染後annexin A4所參與的調控角色，並可提供有用的資訊於胃癌的治療上。 <br> Abstract: Helicobacter pylori (H. pylori) is the first formally recognized bacterial carcinogen. The bacterium uses the type-IV secretion system to deliver a cancer associated protein, CagA, directly into its host cell and then stimulate IL-8 expression, further leads elongation of host cells. Our preliminary results showed that annexin A4 is overexpressed in both tumor tissues and host cancer cells infected by H. pylori. In addition, we found that H. pylori infection indeed stimulates IL-8 expression while annexin A4-specific siRNA oligonucleotide inhibits IL-8 expression in host cells. The activation of the H. pylori type-IV secretion system toward stimulating c-Jun in hosts has been well understood. However, the downstream signaling of c-Jun, leading to cell elongation or induction of IL-8 are still unclear, hampering our understanding of the roles of annexin A4 during H. pylori infection. We propose that c-Jun stimulates its downstream signaling molecules, RACK1, PKC and annexin A4, which then induces IL-8 and other annexin A4 downstream gene expression, leading to cell elongation and invasion. The overall goal of this proposal is to elucidate the gene network of host cells infected by Helicobacter pylori and annexin A4 involved signaling and regulation in gastric cancer. We will collaborate with Dr. James C. Liao at University of California, Los Angeles to identify perturbed transcription factors (TFs) and pathways and separate the effects of multiple TFs. Understanding how key signaling pathways are rewired in H. pylori-infected host cell offers new insights into molecular basis of H. pylori-induced malignancy and potential targets for therapy of gastric cancer. Our specific aims are 1. to determine the regulatory roles of annexin A4 upstream genes involved in H. pylori-infected host cells by using coimmunoprecipitation experiments, pull-down assays, knockdown and immunoblotting experiments; and 2. to construct annexin A4 involved downstream gene network and identify perturbed TFs and pathways in H. pylori-infected host cells using time-course transcriptome measurements and bioinformatics analysis, and verified by q-PCR, yeast two-hybrid system, and pull-down assays. This study will extend our understanding of signal transduction and give us insight of the mechanism of annexin A4 in H. pylori-infected host cells. This information could be useful for therapy of human gastric cancer.幽門桿菌基因網路胃癌annexin A4Helicobacter pylorigene networkgastric cancerannexin A4