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

描述（由申请人提供）：肝细胞癌（HCC）是全球第五大常见癌症，其发展在很大程度上与已知的危险因素相关；常见的危险因素包括人类乙型肝炎病毒（HBV）慢性肝脏感染和长期饮酒。在具有这两种危险因素的个体中，HCC的发生率增加。了解慢性HBV感染和饮酒如何影响HCC的发展和转化，对于开发预防HBV和酒精相关HCC的治疗方法非常重要。我的申请侧重于非结构性乙型肝炎病毒X蛋白（HBx）和酒精暴露对细胞增殖途径的影响，暴露于这两种药物如何加剧这些影响以及HBV复制和肝细胞生理学的后果。我们已经开发了分离和培养原代大鼠肝细胞的方法，从而产生了一个生物学相关的系统来进行我们的研究。我们将使用这个系统来实现以下具体目标：(1)通过检测细胞增殖和细胞周期蛋白的调节来确定HBx、HBV和乙醇对细胞周期进程的影响；(2)我们将分析乙醇暴露和细胞周期进程对HBV复制的影响，并探索特定细胞周期蛋白在这种关系中的作用；(3)确定乙醇和HBx依赖性细胞增殖途径的调节如何影响肝细胞凋亡。这些研究的长期目标是了解HBx和酒精对细胞增殖影响的机制，以便更好地了解HCC发展中激活的信号通路。我们假设，HBx和酒精对细胞周期进程的调节最终会激活肝细胞的凋亡途径，当HBx/HBV和酒精联合使用时，会更大程度地诱导细胞凋亡。饮酒和慢性乙肝病毒感染导致肝细胞的高周转率；这可能导致在再生的病变肝脏中最终选择抵抗凋亡信号的肝细胞。慢性HBV感染和饮酒的结合比单独暴露于乙醇或HBV感染导致肝损伤和HCC发展更快。与在永生化或转化细胞中进行的类似研究相比，正常肝细胞的使用提供了更具生物学相关性的系统。我们的研究将有助于更好地理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.