Role of Autotaxin in HCV-associated Hepatocellular Carcinoma

自分泌运动因子在 HCV 相关肝细胞癌中的作用

• 批准号: 8089443
• 负责人: Neerja Kaushik-Basu
• 金额: $ 10.32万
• 依托单位: UNIV OF MED/DENT OF NJ-NJ MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-06-14 至 2013-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8089443
• 关键词: Address; Biochemical Genetics; Cell Culture Techniques; Cells; Chronic Hepatitis C; Clinical Research; Coupled; Data; Development; Disease; Employment; Enzymes; Etiology; Exhibits; Genes; Goals; Guanosine Triphosphate Phosphohydrolases; Hepatitis C; Hepatitis C virus; Hepatocyte; Human; Integration Host Factors; Intervention; Investigation; Length; Link; Liver; Liver Fibrosis; Lysophospholipids; Malignant Neoplasms; Mediating; Messenger RNA; Modality; Modeling; Molecular; Molecular Genetics; Open Reading Frames; Pathogenesis; Patients; Plasma; Play; Prevention; Primary carcinoma of the liver cells; Proteins; RNA replication; Regulation; Replicon; Reporting; Risk Factors; Role; Sampling; Serum; Signal Pathway; Signal Transduction; Staging; Testing; Therapeutic Intervention; Tissues; Tumor Tissue; Viral Pathogenesis; Viral Proteins; Virus Diseases; Virus Replication; base; cancer cell; cancer type; hepatoma cell; insight; lysophosphatidic acid; mRNA Expression; novel; phosphoric diester hydrolase; promoter; public health relevance; pyrophosphatase; research study; response; rho GTP-Binding Proteins; tumor; tumorigenic; viral RNA; virus pathogenesis

DESCRIPTION (provided by applicant): Hepatitis C virus (HCV) infection is the most significant risk factor for the development of hepatocellular carcinoma (HCC), a major liver malignancy and cancer type worldwide. The molecular genetics and signaling pathways associated with HCV-associated HCC pathogenesis remain poorly understood. Our long-term goal is to elucidate the molecular mechanisms underlying progression of chronic HCV to HCC. Autotaxin (ATX), an ectonucleotide pyrophosphatase/phosphodiesterase 2 enzyme and a potent cell stimulating motogen is over-expressed in various malignant tumor tissues and has been implicated to confer the tumorigenic and metastatic potential of a variety of cancer cells. In 2007, two groups provided the first evidence that the serum ATX activity and plasma lysophosphatidic acid (LPA) levels are increased in chronic hepatitis C in association with liver fibrosis, and that ATX and genes related to ATX signaling pathway were upregulated in HCC patients co-infected with HCV. Is this the cause or consequence of HCV infection? And how does aberrant regulation of ATX impact HCV replication and pathogenesis? We postulate that "ATX over-expression and signaling may be an important determinant in the replication and pathogenesis of HCV". Our hypothesis is based on some novel and vital clues linking ATX expression to HCV infection and pathogenesis. In preliminary experiments we observed that ATX mRNA expression is upregulated in the liver tissues of HCV-infected patients and its expression is further enhanced in HCV- associated HCC samples, consistent with the 2007 clinical study. Further, the expression levels of ATX mRNA were upregulated in HCV replicon cells versus replicon cured cells, suggesting a role for HCV in inducing ATX expression. This observation coupled with our data that HCV replicon cells secrete ATX, suggest that the HCV infected liver may potentially contribute to the aberrant expression of ATX in HCV- infected patients and patients with HCV-associated HCC. We found that the ATX promoter was activated and stimulated in HCV replicon cells, thus implicating HCV proteins and host-factors in HCV-infected cells to potentially play a role in aberrant regulation of ATX. Further, over-expression of ATX in HCV RNA bearing human hepatoma cells induced RhoA expression, activated RhoA and stimulated HCV RNA replication. Conversely, blockage of ATX secretion abrogated RhoA induction and ablated HCV RNA replication. We envision that ATX/LPA over-expression during the course of HCV infection may de-regulate mechanisms involved in Rho GTPase signaling thus contributing towards HCV pathogenesis. To test our hypothesis and to extend our findings two independent but complementary specific aims are proposed. In Aim 1 we will investigate the role of viral proteins and host factors in aberrant regulation of ATX expression during HCV infection and pathogenesis. In Aim 2, we propose to address the role of ATX in HCV replication and pathogenesis mechanisms. To investigate these aspects, we propose to employ nontransformed human hepatocytes (HH4 cells) conditionally expressing the full-length HCV ORF (HH4-HCV) as models for the early stage of HCV infection, and C-5B replicon cells which replicate HCV RNA in hepatoma cells to address questions pertaining to the scenario in the HCV infected tumor microenvironment. These objectives will be achieved via multi-prong approach, including cell culture, biochemical and molecular genetics. We envisage that our findings will provide crucial insights into modulation of ATX during HCV infection and further clarify the role of ATX in HCV replication and pathogenesis. These investigations may provide rational target for therapeutic intervention of HCV. PUBLIC HEALTH RELEVANCE: The proposed studies have the potential to provide crucial insights into regulation and role of autotaxin (ATX), a tumorigenic and metastatic protein, in HCV infection and pathogenesis mechanisms and may likely identify novel modalities for therapeutic intervention of Hepatitis C.

描述（由申请人提供）：丙型肝炎病毒（HCV）感染是肝细胞癌（HCC）发展的最重要的危险因素，肝细胞癌（HCC）是全球主要的肝脏恶性肿瘤和癌症类型。与HCV相关的HCC发病机理相关的分子遗传学和信号通路仍然知之甚少。我们的长期目标是阐明慢性HCV对HCC的进展的分子机制。自身赛（ATX），ecton核苷酸焦磷酸酶/磷酸二酯酶2酶和有效的细胞刺激MOTOGON在各种恶性肿瘤组织中过表达，并已涉及赋予各种癌细胞的肿瘤性和转移性潜力。在2007年，两组提供了第一个证据表明，慢性丙型肝炎与肝纤维化相关的血清ATX活性和血浆溶血磷脂酸（LPA）水平升高，并且在与HCV共同感染的HCC患者中，与ATX信号通路相关的ATX和ATX和基因都被上调。这是HCV感染的原因或结果吗？ ATX的异常调节如何影响HCV复制和发病机理？我们假设“ ATX过表达和信号传导在HCV的复制和发病机理中可能是重要的决定因素”。我们的假设基于一些新颖而重要的线索，将ATX表达与HCV感染和发病机理联系起来。在初步实验中，我们观察到在HCV感染患者的肝组织中ATX mRNA表达上调，并且与2007年临床研究一致的HCV相关HCC样品在HCV相关的HCC样品中进一步增强。此外，在HCV复制子细胞中与复制子固化的细胞中，ATX mRNA的表达水平上调，这表明HCV在诱导ATX表达中的作用。该观察结果与我们的数据相结合的HCV复制细胞分泌ATX，表明HCV感染的肝脏可能有可能导致HCV感染的患者和与HCV相关的HCC患者中ATX的异常表达。我们发现在HCV复制子细胞中激活了ATX启动子并刺激了HCV蛋白和HCV感染细胞中的宿主因子，从而可能在ATX的异常调节中起作用。此外，在轴承人肝癌细胞的HCV RNA中ATX的过表达诱导RhoA表达，激活RhoA并刺激HCV RNA复制。相反，ATX分泌的阻塞废除了RhoA诱导和消融的HCV RNA复制。我们设想，在HCV感染过程中，ATX/LPA过表达可能会取消调节Rho GTPase信号传导的机制，从而有助于HCV发病机理。为了检验我们的假设并扩展了我们的发现，提出了两个独立但互补的特定目标。在AIM 1中，我们将研究病毒蛋白和宿主因子在HCV感染和发病机理期间ATX表达异常调节中的作用。在AIM 2中，我们建议解决ATX在HCV复制和发病机理中的作用。为了研究这些方面，我们建议采用未经转化的人肝细胞（HH4细胞）条件表达全长HCV ORF（HH4-HCV）作为HCV感染的早期阶段的模型，C-5B复制细胞和复制HEPATOMA细胞中的HCV RNA以解决与SENAR的相关性的HEPATOMA细胞中复制HCV RNA的模型。这些目标将通过多支出方法来实现，包括细胞培养，生化和分子遗传学。我们设想，我们的发现将为HCV感染期间ATX的调节提供至关重要的见解，并进一步阐明ATX在HCV复制和发病机理中的作用。这些研究可能为HCV的治疗干预提供合理的目标。 公共卫生相关性：拟议的研究有可能在HCV感染和发病机制中提供至关重要的洞察力（ATX）（ATX）（ATX）（ATX）（ATX）的作用（ATX），并可能确定了乙型肝炎治疗的新型方法。