Role of Inflammation and DNA Damage-Repair in HCV Carcinogenesis

炎症和 DNA 损伤修复在 HCV 癌变中的作用

• 批准号: 7246016
• 负责人: Michael M.C. Lai
• 金额: $ 26.31万
• 依托单位: UNIVERSITY OF SOUTHERN CALIFORNIA
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-04-01 至 2012-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7246016
• 关键词: Role; Inflammation; DNA; Damage; Repair

Specific Aims Hepatocellular carcinoma (HOC) is common following hepatitis C virus (HCV) infection and in diabetics or alcoholics with inflammation-related liver pathology. Alcoholism and obesity increases the gut-derived endotoxin whose co-receptor is TLR4. We have previously shown that HCV infection increases expression of TLR4. Commonality of TLR4 suggests synergism between HCV and alcoholism/obesity. Our studies in a mouse model of HCC suggest that the combination of inflammation-induced hepatocyte regeneration plus impairment of DNA damage repair caused by the viral core protein leads to chromosomal instability and hepatic oncogenesis. According to the model diagrammed below, activation of the IKKp/c-Jun/Stat3 plus inflammation cytokines (TNF-a, IL-6) by viral infection and alcoholism/obesity leads to hepatocyte DNA damage plus upregulation of mitogens and hepatocyte proliferation. Together, these changes lead to increased incidence of HCC. HYPOTHESES 1. HCV-induced Toll-like receptor 4 (TLR4) enhances TNF-a, leading to synergism between HCV and alcoholism/diabetes for oncogenic potential. 2. HCV inhibits DNA damage defense barrier, including DNA damage-induced signal transduction (ATM sand ATR) and complex formation of nonhomologous end-joining (NHEJ). 3. HCV infection-associated inflammation facilitates carcinogenesis through IKKp/c-jun/STAT3 activation. SPECIFIC AIMS 1. Determine the effect of TLR4 gene disruption on HCC in an alcohol/diabetes mouse model and core/NS5A transgenic mice. 2. Determine the mechanism of inhibition of DNA damage-repair by viral proteins, and the possible association of the core with the NHEJ complex by proteomics analysis with Dr. Deshaies (California Institute of Technology). 3. Determine the role of c-jun/IKKp/STAT3 in HCV-associated HCC in a conditional knockout animal model.

具体目标 肝细胞癌（HOC）是常见的丙型肝炎病毒（HCV）感染和糖尿病患者 或患有炎症相关肝脏病变的酗酒者。酗酒和肥胖会增加肠道源性 内毒素，其共受体是TLR 4。我们先前已经证明，HCV感染增加了 TLR4。TLR 4的共同性表明HCV与酗酒/肥胖之间存在协同作用。我们的研究在一个 肝癌小鼠模型表明，炎症诱导的肝细胞再生加上 由病毒核心蛋白引起的DNA损伤修复的损伤导致染色体不稳定性， 肝肿瘤发生根据下面的模型，IKKp/c-Jun/Stat 3 + 病毒感染和酒精中毒/肥胖引起的炎症细胞因子（TNF-α，IL-6）导致肝细胞DNA 损伤加上有丝分裂原和肝细胞增殖的上调。这些变化共同导致 增加HCC的发病率。 假设 1. HCV诱导的Toll样受体4（TLR 4）增强TNF-α，导致HCV和TNF-α之间的协同作用。 酒精中毒/糖尿病的潜在致癌性。 2. HCV抑制DNA损伤防御屏障，包括DNA损伤诱导的信号转导（ATM 和ATR）和非同源末端连接（NHEJ）的复合物形成。 3. HCV感染相关炎症通过IKKp/c-jun/STAT 3激活促进癌发生 具体目标 1.在酒精/糖尿病小鼠模型中确定TLR 4基因破坏对HCC的影响， core/NS 5A转基因小鼠。 2.确定病毒蛋白抑制DNA损伤修复的机制，以及可能的 Deshaies博士（加州）通过蛋白质组学分析， 技术研究所）。 3.在条件性基因敲除动物中确定c-jun/IKKp/STAT 3在HCV相关HCC中的作用 模型