Oxidative Stress and Hepatocellular Carcinoma

描述（由申请人提供）：本提案基于以下假设：氧化应激和损伤是慢性肝病患者肝细胞癌（HCC）的常见和主要驱动因素，而抗氧化能力的下降增加了慢性肝病患者发生HCC的可能性。因此，本研究的长期目标是确定丙型肝炎（HCV）感染后氧化应激介导的HCC发展机制，并确定与HCC进展相关的危险因素和氧化应激介导的生物标志物。一些临床研究表明，低水平的超氧化物歧化酶（SOD）与HCC的发生存在因果关系；几个用于重现HCC发展的小鼠模型显示氧化损伤水平升高；具有氧自由基代谢遗传缺陷的突变小鼠在长时间孵育后发生HCC。综上所述，这些研究提示氧化应激可能在慢性肝病HCC的发展中起直接而重要的作用。我们将重点研究hcv介导的HCC发展、氧化应激和SOD缺乏之间的相互作用。本文提出了三个特定目的，以确定HCV感染、ROS生成、钙稳态与肝癌发生之间的关系，确定SOD在HCV介导的肝癌发生中的作用，并通过比较蛋白质组学分析确定慢性HCV感染和SOD缺乏的共同分子靶点。体外和体内研究将使用已建立的人肝细胞系、原代人肝细胞、HCV转基因小鼠和CuZnSOD缺陷小鼠进行，以确定HCV蛋白对ROS生成、钙稳态和氧化还原敏感信号分子激活的影响。将采用遗传方法降低HCV转基因小鼠的SOD水平，以调节HCC的发展过程。此外，将采用不同的蛋白质组学工具和程序来鉴定HCV转基因小鼠和CuZnSOD缺陷小鼠中易受氧化修饰的分子。

DESCRIPTION (provided by applicant): This proposal is based on the hypothesis that oxidative stress and injury is a common and major driving force of hepatocellular carcinoma (HCC) in chronic liver diseases and that decreased antioxidant capacity increases the probability of HCC development in patients with chronic liver diseases. Therefore, the long term objectives of this proposal are to determine the mechanism underling oxidative stress-mediated HCC development from hepatitis C (HCV) infection and to identify risk factors and oxidative stress-mediated biomarkers associated with the progression of HCC. Several clinical studies showed a causal relationship between low levels of superoxide dismutase (SOD) and the development of HCC; several mouse models generated to recapitulate HCC development were shown to have elevated levels of oxidative damage; and mutant mice with genetic defects in oxygen free radical metabolism develop HCC after a long incubation time. Collectively, these studies suggest that oxidative stress may play a direct and important role in the development of HCC in chronic liver diseases. We will focus our studies on the interplay between HCV-mediated HCC development, oxidative stress, and SOD deficiency in this proposal. Three Specific Aims are proposed to determine the relationship between HCV infection, ROS production, calcium homeostasis, and hepatocarcinogenesis, to determine the role of SOD in the development of HCV-mediated hepatocarcinogenesis, and to identify molecular targets common to chronic HCV infection and SOD deficiency by comparative proteomic analyses. In vitro and in vivo studies using established human liver cell line, primary human hepatocytes, HCV transgenic mice, and CuZnSOD deficient mice will be carried out to determine the effects of HCV proteins on ROS production, calcium homeostasis, and the activation of redox-sensitive signaling molecules. A genetic approach will be used to reduce SOD levels in HCV transgenic mice to modulate the course of HCC development. In addition, different proteomic tools and procedures will be implemented to identify molecules that are vulnerable to oxidative modification in HCV transgenic and CuZnSOD deficient mice.