CELL AND MOLECULAR BIOLOGY OF RAT HEPATOCARCINOGENESIS

大鼠肝癌发生的细胞和分子生物学

• 批准号: 5206979
• 负责人: HENRY C PITOT
• 金额: --
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/5206979
• 关键词: aldehyde dehydrogenases; carcinogenesis; cell growth regulation; chemical carcinogenesis; gene expression; genetic disorder; genetic markers; genetic regulation; genetically modified animals; hydro lyase; laboratory rat; liver cells; liver neoplasms; molecular oncology; neoplasm /cancer genetics; neoplastic process; nucleic acid sequence; preneoplastic state; protein glutamine gamma glutamyltransferase; tissue /cell culture; tumor suppressor genes

This research program is directed toward an understanding of the regulation of genetic expression in normal, preneoplastic, and neoplastic liver in the rat. The approach utilized will be to study the fine structure of regulation of several genes whose expression in preneoplastic and/or neoplastic liver is significantly different from normal, to characterize more completely the stage of progression, and to characterize hepatocarcinogenesis in a transgenic model as compared to multi-stage carcinogenesis induced by chemicals in the rat. The structure and function of the regulatory components of the serine dehydratase (SDH), aldehyde dehydrogenase (Type 3) (ALDH) and gamma- glutamyl transpeptidase (GGT) genes, all of whose expression is abnormal during hepatocarcinogenesis, will be characterized. Characterization will include the determination of the specific nucleotide sequences involved in the regulation of the expression of these genes in vivo, the identification and characterization of protein(s) that bind to the regulatory sequences of these genes, the levels of such proteins in nuclei of normal, preneoplastic and malignant hepatocytes, and functioning of the regulatory sequences of these genes in their expression during preneoplasia and overt neoplasia. Utilizing a model developed in this laboratory for the study of multi- stage hepatocarcinogenesis in rat liver, we plan to develop better methods to quantitate the development of the stage of progression in hepatocarcinogenesis, to characterize this stage at both the cellular and molecular levels and to develop quantitative methods for the identification of progressor agents. Characterization of the stage will involve a study of the regulation of the expression of several known and potential "marker" genes utilizing cytochemical methods. Chromosomal abnormalities which develop early during the formation of hepatocellular carcinoma in the rat in the stage of progression and the specificity of such abnormalities for the evolution of this stage will be determined. Potential tumor suppressor genes, especially the p53 gene, will be characterized as to their chromosomal localization and any mutation in their sequences, the latter initially in relation to the p53 gene. We will also use a colony of transgenic rats carrying the SV40 T antigen transgene under the control of the mouse albumin promoter/enhancer to compare genetically programmed hepatocarcinogenesis with chemically induced hepatocarcinogenesis. The stages of initiation, promotion, and progression will be delineated in the transgenic model and compared with these stages occurring during the chemical induction of hepatocarcinogenesis. The effect of environmental factors including hormones, diet, and xenobiotics on the natural history of genetically programmed hepatocarcinogenesis will be determined. Characterization of both neoplastic and morphologically normal hepatocytes from the transgenic animals will be carried out in vitro. Together these studies should enable us to define more accurately the critical genetic characteristics of multi-stage hepatocarcinogenesis in the rat, especially during the stage of progression, and to gain a better understanding of the mechanisms of the abnormalities in genetic expression characteristic of the stages of promotion and progression.

这项研究计划旨在了解 正常、癌前和癌前病变组织中基因表达的调控 大鼠肝脏肿瘤。所采用的方法将是研究 几个基因表达调控的精细结构 癌前和/或肿瘤性肝脏与 正常，更全面地描述进展的阶段，并 转基因模型中肝癌发生的特征与 化学物质对大鼠的多阶段致癌作用。这个 丝氨酸调节成分的结构和功能 脱水酶(SDH)、乙醛脱氢酶(ALDH)和γ- 谷氨酰转肽酶(GGT)基因，表达均异常 在肝癌发生过程中，将具有特征性。表征 将包括特定核苷酸序列的测定 参与这些基因在体内表达的调节， 结合蛋白(S)的鉴定与鉴定 这些基因的调控序列，这些蛋白质在 正常、癌前和恶性肝细胞的核，以及 这些基因的调控序列在其 在癌前病变和显性肿瘤中的表达。 利用本实验室开发的一个模型来研究多个 在大鼠肝脏发生肝癌阶段，我们计划发展得更好 定量研究进展期进展的方法 肝癌发生，从细胞和细胞两个方面描述这一阶段 和分子水平，并开发定量方法 进步因子的识别。舞台人物形象的塑造 涉及对几个已知和 利用细胞化学方法进行潜在的“标记”基因。染色体 肝细胞形成过程中早期发展的异常 大鼠肿瘤进展期及其特异性的研究 这一阶段演变的这种反常现象将被确定。 潜在的肿瘤抑制基因，特别是p53基因，将是 特征是它们的染色体定位和任何突变 它们的序列，后者最初与p53基因有关。 我们还将使用一群携带SV40T抗原的转基因大鼠 小鼠白蛋白启动子/增强子控制下的转基因 基因程序性肝癌发生与化学致癌的比较 诱发肝癌的发生。启动阶段、推广阶段和 进展将在转基因模型中描绘出来，并与 这些阶段发生在化学诱导过程中 肝癌的发生。环境因素的影响包括 激素、饮食和外源生物对遗传病自然历史的影响 程序性肝癌的发生将被确定。特征描述 肿瘤和形态正常的肝细胞均来自 转基因动物将在体外进行。把这些研究放在一起 应该使我们能够更准确地定义关键的基因 大鼠多阶段肝癌发生的特点， 尤其是在进步阶段，为了获得更好的 对遗传基因异常机制的认识 表现出提升和进步阶段的特点。