Cellular Responses to Oxidative Stress in Models of Colon Cancer Development

描述（由申请人提供） 人类暴露于环境中的多种化学（例如污染物和药物）和物理（例如辐射）试剂，这些试剂在构成组织和器官系统的大多数细胞类型中诱导氧化应激。以活性氧（ROS）水平增加为特征的氧化应激可诱导异常信号转导和对细胞大分子（包括脂质、蛋白质和核酸）的氧化损伤。这种氧化变化直接导致与几种重要的人类疾病相关的各种有害生物学终点，包括心血管和神经退行性疾病和癌症。一些证据表明，氧化应激、炎症和结肠癌的发展之间存在联系。结直肠癌是第三大最常见的癌症，也是美国癌症死亡的第二大原因。目前，我们对氧化应激介导结肠肿瘤发展的机制了解甚少。该计划项目更新的总体主题是描述两种主要的应激激活的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性和其他有助于肿瘤发展的生物学变化。该研究计划建立在前一个支持期获得的信息基础上，由五个互补的协同项目组成，这些项目将采用两种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。这些系统在遗传学和生物化学上是易于处理的，并且还将提供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最大优点是，关键目标和系统组件（其中一些在前一个支持期内被鉴定和分析）可以在一组等基因酵母菌株、哺乳动物细胞和个体动物的背景下进行检查，其复杂性和速度尚无法使用人体组织和细胞实现。从这些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。这些细胞损伤和反应途径的解剖将导致更清楚地了解氧化应激在结肠癌发展中的作用，并将揭示预防和干预的新靶点。 背景 这是2002年最初资助的计划项目赠款竞争性续期申请的第一次修订。最初提案的总体主题是了解介导DNA损伤抗性的途径之间的相互关系。最初的计划包括五个研究项目。酵母和细菌系统被用作模型。在竞争性更新中，焦点已转向结肠癌。因此，由Bernard韦斯博士指导的项目将停止，由兰贝斯博士指导的项目取代。根据之前评审员的意见，Siede博士的项目也被删除。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。 在竞争性更新的初始提交中，32篇出版物和手稿被列为计划项目赠款提供支持的直接结果。在这次修订中，这一数字增加到51个。本修订申请中描述的研究重点是描述线粒体和Nox产生的活性氧的致病作用以及对ROS和ROS损伤大分子的反应途径，这些大分子直接导致遗传不稳定性和其他有助于肿瘤发展的生物学变化。酵母仍将用作与哺乳动物肠道肿瘤模型组合的模型系统。 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