Virus-gene interactions during hepatic carcinogenesis

描述（由申请人提供）：肝细胞癌（HCC）是全球癌症相关死亡的主要原因之一。肝细胞癌是一种恶性肿瘤，其发病机制是由遗传和环境因素的组合诱导的。在环境因素中，HBV或HCV感染是主要的危险因素。最近的分子和遗传学研究表明，HBV和HCV病毒蛋白通过去调节对肝细胞增殖、分化和凋亡至关重要的信号通路，在HCC发病过程中发挥直接作用。15然而，HBV或HCV转基因小鼠研究中HCC发展的长潜伏期和低发病率表明，在这些受损的肝细胞中发生了额外的基因突变，其是恶性转化和HCC形成所需的。该提案的目标是描述肝癌发生过程中病毒-基因相互作用的特征。我们假设特定的遗传事件，如c-Myc或c-Met过表达，β-连环蛋白激活突变和肿瘤抑制基因TP53的缺失，将加速HBV或HCV核心转基因小鼠中HCC的发展。为了验证这一假设，我们提出了两个具体目标。在目标一中，我们将确定在HBV转基因小鼠中诱导肝癌发生的遗传改变;在目标二中，我们将确定在HCV核心转基因小鼠中诱导肝癌发生的遗传改变。为了实现这些目标，我们将应用流体动力学转染方法将基因直接靶向（使用表达载体或shRNA构建体）到小鼠肝细胞中进行长期稳定表达。我们计划在HBV或HCV核心转基因小鼠中表达的基因包括：c-Myc、c-Met、N90 - 2-catenin和sh-p53，所有这些基因都代表了在人类HCC发病过程中观察到的常见遗传修饰。通过在小鼠肝脏中表达这些特异性基因，我们将确定当小鼠易受HBV全基因组或HCV核心蛋白表达诱导的肝癌发生时，这些基因改变中的任何一个是否能够加速HCC的发展。总而言之，这些研究将有助于识别在肝癌发病机制中起关键作用的重要驱动癌基因或肿瘤抑制基因。这项研究还将提供新的见解肝癌发展的分子机制的背景下，病毒癌蛋白的表达。从拟议的研究中产生的小鼠模型将显着受益于肝癌研究界，并提供有价值的体内模型，研究肝癌预防和治疗的新策略。

DESCRIPTION (provided by applicant): Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths worldwide. HCC is a type of malignancy whose pathogenesis is induced by a combination of genetic and environmental factors. Among the environmental factors, HBV or HCV infections are the major risk factors. Recent molecular and genetic studies have demonstrated that HBV and HCV viral proteins have direct roles during HCC pathogenesis by de-regulating signaling pathways important for hepatocyte proliferation, differentiation and apoptosis.15 However, the long latency and low incidence rate of HCC development from the HBV or HCV transgenic mice studies suggest that additional genetic mutations occur in these damaged hepatocytes, which are required for the malignant transformation and HCC formation. The goal of the proposal is to characterize the virus-gene interactions during hepatic carcinogenesis. We hypothesize that specific genetic events, such as c-Myc or c-Met overexpression, ¿-catenin activating mutations, and loss of tumor suppressor genes TP53, will accelerate HCC development in HBV or HCV core transgenic mice. To test the hypothesis, we propose two Specific Aims. In Aim One, we will determine the genetic alteration(s) that induces hepatic carcinogenesis in HBV transgenic mice; and in Aim Two, we will determine the genetic alteration(s) that induces hepatic carcinogenesis in HCV Core transgenic mice. To achieve these aims, we will apply hydrodynamic transfection method to directly target genes (using either expression vectors or shRNA constructs) into mouse hepatocytes for long term and stable expression. The genes that we plan to express into HBV or HCV core transgenic mice include: c-Myc, c-Met, N90-2-catenin and sh-p53, all representing common genetic modifications observed during human HCC pathogenesis. By expressing these specific genes into the mouse liver, we will determine whether any of these genetic alterations is able to accelerate HCC development when mice are predisposed to hepatic carcinogenesis induced by HBV entire genome or HCV core protein expression. Altogether, the proposed studies will be of great help in identifying important driver oncogenes or tumor suppressor genes that have critical roles during liver cancer pathogenesis. The study will also provide novel insight into the molecular mechanisms of HCC development in the context of viral oncoprotein expression. The murine models generated from the proposed study will significantly benefit HCC research community and provide valuable in vivo models to study novel strategies for HCC prevention and treatment.