Hepatitis C virus core protein and cell proliferation

描述(申请人提供)：丙型肝炎病毒(丙型肝炎病毒)感染会导致急性和慢性肝炎、肝脏脂肪变性、肝硬变，并最终导致肝细胞癌。丙型肝炎病毒感染导致肝细胞癌形成的分子事件仍然知之甚少。丙型肝炎病毒核心蛋白被认为是导致氧化应激、脂肪变性和癌变的关键病毒成分之一。对此，我们建立了瞬时高效表达丙型肝炎病毒核心蛋白的人肝癌细胞模型。表达核心蛋白的细胞，尤其是Lb基因的细胞，表现出更强的增殖和细胞周期进展。微阵列分析显示，参与细胞生长和致癌信号通路的基因上调，以响应核心蛋白的表达。特别令人感兴趣的是WNT-1及其下游目标WSAP-2的上调。提示WNT-1信号通路可能由核心蛋白激活，部分介导核心蛋白诱导的细胞增殖。WNT-1信号通路在细胞生长和肿瘤发生中起重要作用。WNT-1通路的失调在包括肝癌在内的许多人类肿瘤中都被发现。因此，进一步研究核心蛋白在丙型肝炎病毒核心表达细胞中WNT-1/WSAP-2信号转导途径及其对肝细胞生长的调控作用，可能会进一步探讨核心蛋白诱导细胞增殖的机制。具体目标1将确定核心蛋白刺激细胞增殖的结构-功能基础。负责的序列将由缺失突变体定义，而基因型特异性决定簇(S)将通过嵌合构建物定位。特异性目标2将研究WNT-1/WSAP-2信号通路在介导促进细胞增殖中的作用。我们将进一步验证WNT-1/β-catenin途径的激活是否真的被丙型肝炎病毒核心蛋白激活，并检测抑制WNT-1/WISP-2蛋白的表达是否会像核心蛋白那样诱导细胞生长。这些研究可能阐明CORE诱导细胞增殖的分子机制，并为预防丙型肝炎病毒诱导的肝癌提供新的靶点。

DESCRIPTION (provided by applicant): Hepatitis C virus (HCV) infection causes acute and chronic hepatitis, liver steatosis, cirrhosis, and eventually hepatocellular carcinoma (HCC). The molecular events of HCV infection leading to HCC formation are still poorly understood. HCV core protein has been proposed to be one of the key viral components contributing to oxidative stress, steatosis, and carcinogenesis. In this regard, we have established a human hepatoma cell model of transient and efficient HCV core protein expression. Cells expressing core protein, especially of the lb genotype, displayed increased proliferation and cell cycle progression. Microarray analysis revealed upregulation of genes involved in cell growth and oncogenic signaling pathways in response to core protein expression. Of particular interest is the up-regulation of both wnt-1 and its downstream target WISP-2. These observations suggest that wnt-1 signaling pathway may be activated by HCV core protein and partly mediate cell proliferation induced by the core protein. The wnt-1 signaling pathway is known to play an important role in cell growth and tumorogenesis. The disregulation of wnt-1 pathway has been found in many human tumors including liver cancer. Therefore, further characterization of wnt-1/WISP-2 signaling in HCV core expressing cells and its effect on regulation of liver cell growth may probe into the mechanisms by which the core protein induced cell proliferation. Specific Aim 1 will determine the structural-functional basis whereby the core protein stimulates cell proliferation. The responsible sequence will be defined by deletion mutants, and genotype specific determinant(s) will be located via chimeric constructs. Specific Aim 2 will examine the role of wnt-1/WISP-2 signaling pathway in mediating enhanced cell proliferation. We will further validate activation of the wnt-1/beta-catenin pathway is indeed activated by HCV core protein and examine whether inhibition of wnt-1/WISP-2 protein expression will block cell growth as elicited by core protein. These studies may elucidate molecular mechanisms of core induced cell proliferation and provide novel targets for prevention of HCV induced liver cancer.