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

描述(申请人提供)：长期接触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很复杂，而且还不太清楚。在雌激素诱导的致癌过程中，一个重要的部分是人们越来越意识到，活性氧物种可能在致癌途径中充当信号媒介。本研究试图在与人类乳腺癌相关的动物模型中建立氧化应激在雌激素诱导的乳腺癌发生中的作用的分子机制(S)，并通过使用人乳腺上皮细胞系MCF-10F来确定氧化应激在雌激素诱导的乳腺癌中的重要性。因此，研究人员将描述：雌激素代谢介导的氧化应激的作用(特定目标1)；雌激素受体(ER)在氧化应激产生中的作用(特定目标2)；氧化应激在改变ER依赖的基因调控中的作用(特定目标3)；以及细胞色素P450 1b1在雌激素诱导的氧化应激和随后的癌症发生中的作用(特定目标4)。为了实现特定的目标1-4，大鼠将接受雌激素、抗雌激素、抗氧化剂或代谢激活抑制剂的治疗。在体外方法中，MCF-10F细胞将通过基因插入和基因敲除进行基因操作。然后，这些细胞株将被雌激素、抗雌激素、抗氧化剂或代谢激活抑制剂处理，以研究雌激素受体和抗氧化防御基因在雌激素依赖的氧化应激调节中的作用。对动物的治疗将持续七个月，从早期牺牲的动物群体中获得的信息将用于研究早期治疗期间以及癌前和肿瘤发展阶段的变化。肿瘤发病率和组织病理学将被描述。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房和非靶器官肝脏中进行量化；同时，雌激素-雌激素受体依赖基因的表达和调控也将被量化。鉴于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巨大的潜力。

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.