Hepatitis B Virus X protein and Alcohol Regulation of Cell Cycle Progression

描述(申请人提供)：肝细胞癌(肝细胞癌)是全球第五大最常见的癌症，其发展主要与已知的风险因素有关；常见的风险因素包括慢性肝脏感染人类乙肝病毒(乙肝病毒)和长期饮酒。在有这两种危险因素的个体中，肝细胞癌的发生率增加。了解慢性乙肝病毒感染和饮酒如何影响肝细胞癌的发展和转化，对于开发预防乙肝和酒精相关肝细胞癌的治疗方法非常重要。我的应用重点是非结构性的乙肝病毒X蛋白(HBX)和酒精暴露对细胞增殖途径的影响，暴露在这两种药物下如何加剧这些影响以及对乙肝病毒复制和肝细胞生理的影响。我们已经开发出分离和培养原代大鼠肝细胞的方法，从而产生一个生物学上相关的系统来进行我们的研究。我们将使用该系统来解决以下特定目标：(1)通过检测细胞增殖和细胞周期蛋白的调节，确定HBx、乙肝病毒和乙醇对细胞周期进程的影响；(2)我们将检测乙醇暴露和细胞周期进程对乙肝病毒复制的影响，并探索特定的细胞周期蛋白在这种关系中的作用；(3)确定乙醇和HBx依赖的细胞增殖途径调节对肝细胞凋亡的影响。这些研究的长期目标是从机制上理解HBx和酒精对细胞增殖的影响，以便更好地理解在肝癌发生发展过程中激活的信号通路。我们假设，HBx和酒精对细胞周期进程的调节最终将激活肝细胞的凋亡通路，当HBx/乙肝病毒和酒精联合使用时，将导致更大的凋亡诱导。饮酒和慢性乙肝病毒感染导致肝细胞的高周转率；这可能导致最终在再生的、患病的肝脏中选择对凋亡信号具有抵抗力的肝细胞。慢性乙肝病毒感染和饮酒的组合导致肝损伤和肝细胞癌的进展比酒精暴露或单纯的乙肝病毒感染更快。与在永生化或转化细胞中进行的类似研究相比，使用正常肝细胞提供了一个更具生物学相关性的系统。我们的研究将有助于更好地了解肝癌发生的分子机制。

DESCRIPTION (provided by applicant): The development of hepatocellular carcinoma (HCC), the fifth most common cancer worldwide, is largely associated with known risk factors; common risk factors include chronic infections of the liver with the human hepatitis B virus (HBV) and chronic alcohol consumption. In individuals with both risk factors, there is an increase in the presence of HCC. Understanding how chronic HBV infections and alcohol consumption affect the development of HCC and transformation is important in developing therapies for preventing HBV and alcohol-associated HCC. My application focuses on the effect of the nonstructural, hepatitis B virus X protein (HBx) and alcohol exposure on cell proliferation pathways, how exposure to both agents may exacerbate these effects and the consequence for HBV replication and hepatocyte physiology. We have developed methods for isolating and culturing primary rat hepatocytes, thereby generating a biologically relevant system in which to conduct our studies. We will use this system to address the following specific aims: (1) determine the effects of HBx, HBV and ethanol on cell cycle progression by examining cell proliferation and regulation of cell cycle proteins, (2) we will assay the effect of ethanol exposure and cell cycle progression on HBV replication and explore the roles of specific cell cycle proteins in this relationship and (3) determine how ethanol- and HBx dependent regulation of cellular proliferation pathways impacts hepatocyte apoptosis. The long-term goal of these studies is to generate a mechanistic understanding of the effect of HBx and alcohol on cell proliferation in order to create a better understanding of the signaling pathways activated in the development of HCC. We hypothesize that HBx and alcohol regulation of cell cycle progression will ultimately activate apoptotic pathways in hepatocytes and that, when combined, HBx/HBV and alcohol will cause a greater induction of apoptosis. Alcohol consumption and chronic HBV infection cause a high turnover rate of hepatocytes; this may lead to the eventual selection of hepatocytes resistant to apoptotic signals in a regenerating, diseased liver. The combination of a chronic HBV infection and alcohol consumption causes a more rapid progression of liver injury and HCC development than either ethanol exposure or HBV infection alone. The use of normal hepatocytes provides a more biologically relevant system than similar studies performed in immortalized or transformed cells. Our studies will provide a better understanding of the molecular mechanisms contributing to the development of liver cancer.