QUANTIFYING GENE EFFECTS ON HEPATIC CANCER IN VIVO

这项研究的总体目标是确定以下几种基因在肝癌发生中的作用： 通常在人类和/或小鼠肝肿瘤中鉴定的遗传变化。为了实现这一目标， 采用新开发的新型体内测定系统，比较肝细胞生长测定。作为 在起始材料中，该测定使用已被遗传修饰以反映 提出了致癌途径。从这些动物中分离肝细胞，然后移植到 支持供体瞬时复制的特殊设计的患有肝病的受体小鼠的肝脏 肝细胞：评估供体细胞在新宿主环境中的后续克隆生长， 量化单一或组合遗传修饰对（1） 肝细胞在生长刺激条件下增殖;（2）持续肝细胞生长的能力 在静止的肝脏环境中;和（3）肝细胞进展为恶性转化的风险。 每一项测量都反映了肿瘤细胞的一个重要特征。数据的定量性质。 提供了一个更精确的理解每一个遗传变化的具体贡献，单独和在 联合应用对肝癌的发生有促进作用。最终目标是将该系统作为一种工具， 癌症基因发现，通过将基因表达模式的变化与 肝细胞克隆生长将被鉴定。该提案的具体目标如下。目标1：定义 特定基因改变组合对小鼠肝癌发生的影响。目标2：量化 确定的基因变化对体内肝细胞生长和转化频率的影响。目标3：确定 体内转化肝细胞的生长特性和基因表达模式的变化。 这些实验的成功完成将（1）定义几个高度相关性之间的特定相互作用。 肝移植过程中的相关遗传变化（协同或加性互补，或无互补） 致癌作用;（2）提供遗传和 环境改变，根据其与肝癌的相关性选择，对肝细胞生长潜力的影响;和（3） 将识别在肿瘤进展过程中与癌基因合作的基因组。

The overall goal of this proposed research is to assign a role in hepatocarcinogenesis of each of several genetic changes commonly identified in human and/or mouse liver tumors. To accomplish this objective, a newly developed, novel in vivo assay system is employed, the comparative hepatocyte growth assay. As starting material, this assay uses rodents that have been genetically modified to reflect activation of proposed carcinogenic pathways. Hepatocytes are isolated from these animals, and then transplanted into liver of specially designed recipient mice with liver disease that support transient replication of donor hepatocytes: Evaluation of the subsequent clonal growth of donor cells in the new host environment allows quantification of the influence of single or combined genetic modifications on (1) the rate at which hepatocytes proliferate under growth stimulatory conditions; (2) the capacity for sustained hepatocyte growth in a quiescent liver environment; and (3) the risk for hepatocyte progression to malignant transformation. Each measure reflects an important characteristic of neoplastic cells. The quantitative nature of the data. provides a more refined understanding of the specific contribution of each genetic change, alone and in combination with others, to hepatocarcinogenesis. The final objective is to use this system as a tool for cancer gene discovery, by correlating changes in patterns of gene expression with the changes in hepatocyte clonal growth that will be identified. The proposal has the following specific aims. Aim 1: Define the effects of specified combinations of gene changes on mouse hepatocarcinogenesis. Aim 2: Quantify effects of defined gene changes on hepatocyte growth and transformation frequency in vivo. Aim 3: Identify growth characteristics and changes in the pattern of gene expression of transformed hepatocytes in vivo. Successful completion of these experiments will (1) define specific interactions between several highly relevant genetic changes (synergistic or additive complementation, or no complementation) during hepatic carcinogenesis; (2) provide a systematic and comparative evaluation of the influence of genetic and environmental alterations, selected for their relevance to liver cancer, on hepatocyte growth potential; and (3) will identify gene sets that cooperate with oncogenes during tumor progression.