Molecular Mechanisms & Importance of Oxidative Stress in Estrogen-Induced Carcino

描述（由申请人提供）：长期暴露于雌激素积极参与乳腺癌的发展。现有的数据表明，雌激素形成肿瘤的机制是复杂的，并没有得到很好的理解。在雌激素诱导的致癌作用的一个重要组成部分是越来越多的认识，活性氧可能作为致癌途径的信号剂。本研究拟在与人类乳腺癌相关的动物模型（即雌激素诱导的乳腺癌的雌性ACI大鼠模型）中建立氧化应激在雌激素诱导的致癌作用中的分子机制，并通过使用人类乳腺上皮细胞系MCF-10 F，从而建立氧化应激在雌激素诱导的乳腺癌中的重要性。因此，研究人员将表征：雌激素代谢介导的氧化应激的作用（具体目标1）;雌激素受体（ER）在氧化应激产生中的作用（具体目标2）：氧化应激在修饰ER依赖性基因调控中的作用（具体目标3）;以及，细胞色素P450 1B 1在雌激素诱导的氧化应激和随后的致癌作用（具体目标4）。为实现特定目的1-4，将用雌激素、抗雌激素、抗氧化剂或代谢活化抑制剂处理大鼠。在体外方法中，MCF-10 F细胞将通过基因插入和基因敲除进行遗传操作。然后将这些细胞系用雌激素、抗雌激素、抗氧化剂或代谢活化抑制剂处理，以研究雌激素受体和抗氧化防御基因在调节雌激素依赖性氧化应激中的作用。动物处理将持续7个月，从早期处死的动物组中获得的信息将用于研究早期处理期间以及肿瘤前和肿瘤发育阶段的变化。将描述肿瘤发生率和组织病理学特征。氧化应激的标志物以及抗氧化防御酶的水平将在靶器官乳腺和非靶器官肝脏中进行定量;还将对雌激素-雌激素受体依赖性基因的表达和调节进行定量。考虑到联邦登记处最近将雌激素列为人类致癌物，拟议的研究在开发治疗雌激素诱导的肿瘤的治疗策略方面具有很大的潜力。

DESCRIPTION (provided by applicant): Prolonged exposure to estrogens is actively involved in the development of breast cancers. Available data suggest that the mechanism behind the formation of tumors by estrogens is complex and not well understood. An important part in estrogen-induced carcinogenesis is the growing awareness that reactive oxygen species may serve as signaling agents in carcinogenic pathways. The proposed study seeks to establish the molecular mechanism(s) underlying the role of oxidative stress in estrogen-induced carcinogenesis in an animal model relevant to human breast cancers - namely, the female ACI rat model of estrogen-induced breast cancer - and, by using the human breast epithelial cell line MCF-10F, thus establish the importance of oxidative stress in estrogen-induced breast cancer. Therefore, the investigators will characterize: the role of estrogen metabolism-mediated oxidative stress (Specific Aim 1); the role of estrogen receptors (ERs) in the generation of oxidative stress (Specific Aim 2); the role of oxidative stress in modifying ER-dependent gene regulation (Specific Aim 3); and, the role cytochrome P450 1B1 in estrogen-induced oxidative stress and subsequent carcinogenesis (Specific Aim 4). To accomplish Specific Aims 1-4, rats will be treated with estrogens, anti-estrogens, antioxidants, or with inhibitors of metabolic activation. In in vitro approaches, MCF-10F cells will be genetically manipulated with gene insertions and gene knockouts. These cell lines will then be treated with estrogens, anti-estrogens, antioxidants or inhibitors of metabolic activation to study the roles of estrogen receptors and antioxidant defense genes in the regulation of estrogen-dependent oxidant stress. Treatment of animals will be for seven months and information obtained from groups of animals that have been sacrificed at earlier times will be used to study changes during early treatment periods, as well as during both preneoplastic and neoplastic phases of development. Tumor incidence and histopathology will be characterized. Markers of oxidative stress as well as levels of antioxidant defense enzymes will be quantified both in the target organ breast and the nontarget organ liver; also, expression and regulation of estrogen-estrogen receptor-dependent genes will be quantified. Given the federal register's recent inclusion of estrogens as human carcinogens, the proposed studies have a great potential in the development of therapeutic strategies for the treatment of estrogen-induced neoplasia.