MECHANISTIC HEPATOCARCINOGENESIS IN FISH

描述：（改编自申请人摘要）：申请人提出 一个综合方案，以调查正常和 肿瘤生长，生长控制，致癌物质代谢，DNA修复和 两种鱼模型系统中的肿瘤促进。 发展新、更快 用于生物测定以鉴定潜在致癌物的真核生物模型， 致癌促进剂是研究的迫切需要。 一队 实验病理学家和生物化学家将满足这一研究需求 利用四年持续合作中最有希望的方面。 日本青鳉（Oryzias latipes）是一种小型水族馆硬骨鱼， 在暴露于经证实的哺乳动物遗传毒性物质后， 致癌物质。 潜伏期短，对多种 降低成本，同时保持大量的 暴露的个体主张进一步开发这种体内模型。 该硬骨鱼的病灶、区域和肿瘤的形态特征 模型类似于哺乳动物模型中所见。 很大一部分 鱼类的肝肿瘤是肝细胞和胆管的混合肿瘤 上皮细胞 这项工作表明，鱼的肝脏是丰富的， 在胆管上皮细胞中。 使用虹鳟鱼（Oncorhynchus mykiss），申请人已经开发了分离和维持 胆管上皮细胞和肝细胞在无血清培养物中提供了 研究致癌物引发相关事件的独特机会， 推广. 申请人假设体外和体内分析 胆管上皮细胞和肝细胞的相互作用， 进一步了解这些重要的健康细胞， 环境相关的肿瘤性疾病。 三大具体目标 将得到解决。 它们是：1）在体内精炼青鳉 定量测定正常人肝癌发生动力学模型 和肿瘤性肝生长; 2）确定致癌物的效率 激活，DNA加合物的形成和DNA修复的鳟鱼肝细胞， 胆管上皮细胞和青鳉肝脏;和3）建立生化 生长因子和肿瘤促进剂在肝细胞和胆汁中的作用 上皮细胞 将进行体外分析以快速筛选和 鉴定那些能够作为肿瘤作用环境化合物 发起人。 这些在青鳉模型中的生物测定将确定它们在 体内相关性。 这种分子和细胞筛选将与 体内生物测定以验证体外结果。

DESCRIPTION: (Adapted from applicant's abstract): The applicant proposes an integrated program to investigate characteristics of normal and neoplastic growth, growth control, carcinogen metabolism, DNA repair and tumor promotion in two fish model systems. The development of new, faster eukaryotic models for bioassay to identify potential carcinogens and promoters of carcinogenesis is a pressing need for research. A team of experimental pathologists and biochemists will address this research need using the most promising aspects of four years of continuous cooperation. The Japanese medaka (Oryzias latipes), a small aquarium teleost species, develops tumors of liver after exposure to proven mammalian genotoxic carcinogens. Brief latency period, sensitivity to a variety of procarcinogens and decreased cost while maintaining large numbers of exposed individuals argue for further development of this in vivo model. Morphological characteristics of foci, areas and tumors in this teleost model resemble those seen in mammalian models. A large proportion of the hepatic neoplasms of fishes are mixed tumors of hepatocytes and biliary epithelial cells. This work has shown that livers of fishes are enriched in biliary epithelial cells. Using the rainbow trout (Oncorhynchus mykiss), the applicant has developed methods for isolating and maintaining biliary epithelial cells and hepatocytes in serum free culture providing a unique opportunity for studying events related to carcinogen initiation and promotion. The applicant hypothesizes that in vitro and in vivo analyses of biliary epithelial cells and hepatocytes and their interactions will further our understanding of these important cells in health and environmentally-associated neoplastic disease. Three broad specific aims will be addressed. They are: 1) refine medaka in vivo hepatocarcinogenesis model by quantitatively determining dynamics of normal and neoplastic liver growth; 2) determine the efficiency of carcinogen activation, DNA adduct formation and DNA repair in trout hepatocytes and biliary epithelial cells and in medaka liver; and 3) establish biochemical actions of growth factors and tumor promoters in hepatocytes and biliary epithelial cells. In vitro analysis will be done to rapidly screen and identify those environmental compounds capable of acting as tumor promoters. Bioassay of these in the medaka model will determine their in vivo relevance. This molecular and cellular screening will be linked to in vivo bioassay to validate in vitro findings.