MOLECULAR MECHANISMS OF CARCINOGENESIS IN FERAL FISH

接近100%的老哈德逊河小鳕表现出组织学定义 肝细胞癌，而这种情况是不存在的小鳕 清洁的水路环境。 这些肿瘤的病因 鱼是未知的。 然而，哈德逊河在历史上 受到大量环境污染的影响， 已知的哺乳动物致癌物 增加对癌症发生的认识， 鱼类有可能增加我们对这一过程的理解， 所有脊椎动物的癌症诱导，并可能导致描述 适用于致癌试验的替代种属。 而其他 研究人员已经研究了致癌作用的环境起源， 野生鱼类种群， 这些生物体中缺乏肿瘤形成。 本研究将评估 哈德逊河致癌过程的分子遗传学机制 小鳕鱼 具体来说，我们将确定哈德逊河小鳕是否构成 一个单独的群体， 肿瘤或对环境致癌物的敏感性增加。 这 将通过使用线粒体DNA分析来完成， 确定暴露于以下物质的每个种群的鱼的肿瘤发病率： 清洁或哈德逊河环境。 此外，我们亦会探讨 哈德逊中已知和新的鱼类癌基因的潜在激活 小鳕鱼河。 这种方法将涉及一系列的转染， 将小鳕鱼DNA导入NIH3T3细胞并利用裸鼠共转染 比色法 将对转化的细胞进行外源性鱼DNA测定 序列和癌基因通过使用Southern印迹杂交鉴定。 活化的癌基因将根据其 激活机制和新的癌基因将被克隆， 表征了

Close to 100% of older Hudson River tomcod exhibit histologically defined hepatocellular carcinomas, whereas this condition is absent in tomcod from a clean waterway environment. The etiology of neoplasia in these fishes is unknown. However, the Hudson River has historically been subject to elevated levels of environmental insult with a multitude of known mammalian carcinogens. Increased knowledge of carcinogenesis in fishes has the potential to increase our understanding of the process of cancer induction in all vertebrates, and may result in the description of alternate species suitable for carcinogenesis testing. While other workers have addressed the environmental origin of carcinogenesis in feral fish populations, investigations on the genetic aspects of neoplasia in these organisms are lacking. This study will evaluate molecular genetic mechanisms in the carcinogenic process in Hudson River tomcod. Specifically, we will determine if Hudson River tomcod constitute a separate population with either a genetically programmed predisposition to neoplasia or increased sensitivity to environmental carcinogens. This will be accomplished through the use of mitochondrial DNA analysis and determination of tumor incidence in fish from each population exposed to clean or Hudson River environments. In addition, we will explore the potential activation of both known and novel fish oncogenes in Hudson River tomcod. This approach will involve a series of transfections of tomcod DNA into NIH3T3 cells and use of the nude mouse co-transfection assay. Transformed cells will be assayed for exogenous fish DNA sequences and oncogenes identified by use of Southern blot hybridization. Activated oncogenes will be characterized with respect to their mechanisms of activation and novel oncogenes will be cloned and characterized.