Cellular Responses to Oxidative Stress in Models of Colon Cancer Development

描述(由申请人提供) 人类暴露在环境中的多种化学物质(如污染物和药物)和物理物质(如辐射)中，这些物质会在构成组织和器官系统的大多数细胞类型中引起氧化应激。氧化应激可引起细胞大分子，包括脂质、蛋白质和核酸的氧化损伤和信号转导的异常，其特征是ROS水平升高。这种氧化变化直接导致各种有害的生物终点，与几种重要的人类疾病有关，包括心血管和神经退行性疾病以及癌症。有几条证据表明，氧化应激、炎症和结肠癌的发展之间存在联系。在美国，结直肠癌是第三种最常见的癌症，也是癌症死亡的第二大原因。目前，我们对氧化应激介导结肠癌发生的机制知之甚少。该计划项目更新的总主题是描绘两个主要的应激激活的ROS细胞生成器(线粒体和NOx)的致病作用，并研究ROS和ROS损伤的大分子的反应途径，这些大分子直接导致遗传不稳定和其他有助于肿瘤发展的生物变化。这项研究计划以前一支持期间获得的信息为基础，由五个互补、协同的项目组成，这些项目将使用两个强大的真核模型系统(酵母和小鼠)，以确定真核/哺乳动物氧化应激回路的重要元素。这些系统在基因和生化上都是容易处理的，也将提供一个与人类结肠癌发展相关的重要哺乳动物肠道肿瘤模型。采用这种模型系统的巨大优势是，可以在一组同基因酵母菌株、哺乳动物细胞和单个动物的背景下，以使用人类组织和细胞尚不能达到的复杂程度和速度来检查关键目标和系统组件(其中许多组件是在前一支持期间确定和分析的)。从这种研究中产生的信息随后可以直接和快速地转化为利用人类材料的研究。对这些细胞损伤和反应途径的剖析将使人们更清楚地了解氧化应激在结肠癌发生中的作用，并将揭示预防和干预的新靶点。 背景 这是对计划项目赠款的竞争性续签申请的第一次修订，该申请最初是在2002年资助的。最初提案的总体主题是了解介导对DNA损伤的抗性的途径之间的相互关系。最初的计划由五个研究项目组成。以酵母菌和细菌系统为模型。在竞争的更新中，焦点已被重新定向到结肠癌。因此，由Bernard Weiss博士指导的项目将停止，取而代之的是由Lambeth博士指导的项目。根据之前评审者的评论，Siede博士的项目也已被取消。因此，目前的申请有四个研究项目。Shadel博士和Doetsch博士将指导其中两个项目，第四个项目将由Kow博士和Crouse博士联合指导。除了四个研究项目外，还有一个行政核心和一个小鼠肿瘤模型和哺乳动物细胞培养核心。在最初提交的竞争性更新报告中，32种出版物和手稿被列为方案项目赠款提供支持的直接结果。在这个修订版中，这个数字增加到了51个。本修订申请中描述的研究重点是描绘由线粒体和NOx产生的活性氧物种的致病作用，以及对ROS和ROS损伤的大分子的反应途径，这些大分子直接导致遗传不稳定和其他有助于肿瘤发展的生物变化。酵母仍将作为模型系统与哺乳动物肠道肿瘤模型相结合。 将计划作为一项综合努力

DESCRIPTION (provided by applicant) Humans are exposed to a multitude of chemical (e.g. pollutants and drugs) and physical (e.g. radiation) agents in the environment that induce oxidative stress in most cell types that comprise tissues and organ systems. Oxidative stress, characterized by increased levels of reactive oxygen species (ROS), can induce both aberrant signal transduction and oxidative damage to cellular macromolecules, including lipids, proteins and nucleic acids. Such oxidative changes directly contribute to a variety of deleterious biological endpoints associated with several important human diseases, including cardiovascular and neurodegenerative disorders and cancer. Several lines of evidence have revealed links among oxidative stress, inflammation and the development of colon cancer. Colorectal cancer is the third most commonly diagnosed cancer and is the second leading cause of cancer death in the United States. Currently, we have a very poor understanding of the mechanisms by which oxidative stress mediates colon tumor development. The overall theme of this program project renewal is to delineate the pathogenic contributions of two major, stress-activated cellular generators of ROS (mitochondria and Nox) and to investigate the response pathways to ROS and to ROS-damaged macromolecules which directly lead to genetic instability and other biological changes that contribute to tumor development. This program of investigation builds from information obtained during the previous support period and is comprised of five complementary, synergistic projects that will employ two powerful eukaryotic model systems (yeast and mice) in order to define important elements of the eukaryotic/mammalian oxidative stress circuitry. These systems are genetically and biochemically tractable and will also provide an important mammalian intestinal tumor model that is relevant to human colon cancer development. The great advantage of employing such model systems is that key targets and system components (a number of which were identified and analyzed during the previous period of support) can be examined within the context of a battery of isogenic yeast strains, mammalian cells, and individual animals at a level of complexity and pace not yet achievable using human tissues and cells. The information generated from such studies can subsequently be directly and quickly translated into studies utilizing human material. Dissection of these cellular damages and response pathways will lead to a clearer understanding of the role of oxidative stress in colon cancer development and will reveal novel targets for prevention and intervention. BACKGROUND This is the first revision of a competitive renewal application for a Program Project grant that was initially funded in 2002. The overall theme of the initial proposal was to understand the interrelationships between the pathways that mediate resistance to DNA damage. The initial program consisted of five research projects. Yeast and bacterial systems were used as models. In the competitive renewal, the focus has been redirected toward colon cancer. Thus, the project that was directed by Dr. Bernard Weiss will be discontinued and replaced by a project directed by Dr. Lambeth. Based on the comments of the previous reviewers, the project by Dr. Siede has also been eliminated. Thus, the current application has four research projects. Dr. Shadel and Dr. Doetsch will direct two of the projects and the fourth project will be directed jointly by Drs. Kow and Crouse. In addition to the four research projects, there is an administrative core and a mouse tumor model and mammalian cell culture core. In the initial submission of the competitive renewal, 32 publications and manuscripts were listed as a direct result of the support provided by the program project grant. In this revised version, the number has increased to 51. The focus of the studies described in this revised application is to delineate the pathogenic contributions of the reactive oxygen species generated by the mitochondria and the Nox and the response pathways to ROS and ROS-damaged macromolecules which directly lead to genetic instability and other biological changes that contribute to tumor development. Yeast will still be used as a model system in combination with mammalian intestinal tumor models. PROGRAM AS AN INTEGRATED EFFORT