Biointeractions of Antiestrogens with Nitric Oxide

描述(申请人提供)：雌激素/激素替代疗法(HRT)用于绝经后症状的使用率大幅下降，因为与激素和化学致癌相关的乳腺癌风险增加。选择性雌激素受体调节剂(SERM)可以提供HRT的替代方案，但由于副作用(包括致癌)的风险，开发一直停滞不前。苯并噻吩SERM(BT-SERM)雷洛昔芬是目前临床上唯一用于绝经后综合征和乳腺癌化学预防的SERM。在一些组织中，SERM作为雌激素激动剂，雌激素和SERM都被氧化代谢成亲电的苯二酚，有可能产生ROS。雌激素激动剂已被证明能升高细胞中的NO；NO与乳腺癌的发生有关。喹诺酮、ROS和NO可以相互作用，也可以修饰蛋白质和损伤DNA。这项建议旨在了解如何通过不调节和适当设计具有氧化还原活性但本身不致癌的SERM来减弱雌激素依赖的致癌作用，为设计安全、非致癌的HRT及以后的SERM提供基础。在目标1中，将合成新的BT-SERM，并将其作为细胞探针。体外DNA损伤和蛋白质修饰将用LC-MS/MS进行研究，目的是确定(抗)雌激素产生的醌、NO和ROS与蛋白质和核酸加合物相互作用的蛋白质和核酸加合物，以及醌结构对这些产物的影响，以便与Aim 2细胞培养结果进行比较。目的2将研究乳腺细胞培养中氧化DNA损伤导致细胞凋亡或恶性转化的调控。我们假设乳腺癌细胞的恶性转化反映了雌激素的化学致癌作用，因此在目标3中计划的实验中将预测BT-SERM和NO调节治疗将减弱肿瘤的形成。在目标3中，将使用建立的雌激素诱导的乳腺癌变模型ACI大鼠来研究一种BT-SERM和NO调节在致癌和肿瘤消退中的作用。 公共卫生相关性：SERM是一类用于绝经后综合征和预防和治疗雌激素依赖型乳腺癌的药物。与雌激素替代治疗相关的风险-收益比和SERM的副作用可能与组织一氧化氮(NO)水平有关。这类药物的重要性要求更好地了解SERM、雌激素和NO之间的相互作用，以此作为改进治疗药物的基础。

DESCRIPTION (provided by applicant): Use of estrogen/hormone replacement therapy (HRT) for post-menopausal symptoms has plummeted because of increased breast cancer risk associated with hormonal and chemical carcinogenesis. Selective estrogen receptor modulators (SERMs) could provide an alternative to HRT, but development has stalled because of the risk of side effects including carcinogenesis. The benzothiophene SERM (BT-SERM) raloxifene is currently the sole SERM in clinical use for postmenopausal syndrome and breast cancer chemoprevention. SERMs act as estrogen agonists in some tissues and both estrogens and SERMs are oxidatively metabolized to electrophilic quinones with potential to generate ROS. Estrogen agonists have been shown to elevate cellular NO; NO is implicated in breast cancer tumorigenesis. Quinones, ROS, and NO can interact chemically and also modify proteins and damage DNA. This proposal is directed at understanding how estrogen-dependent carcinogenesis can be attenuated by NO modulation and by appropriately designed SERMs that are redox-active but not themselves carcinogenic, to provide a basis for design of safe, non-carcinogenic SERMs for HRT and beyond. In Aim 1, new BT-SERMs will be synthesized and profiled as cellular probes. In vitro DNA damage and protein modification will be studied by LC-MS/MS. This aim will determine the protein and nucleic acid adducts of the chemical interaction with quinones, NO, and ROS generated by (anti)estrogens, and the influence of quinone structure on these products, allowing comparison with Aim 2 results in cell cultures. Aim 2 will study modulation of oxidative DNA damage in mammary cell cultures leading to apoptosis or malignant transformation. We hypothesize that malignant transformation of breast cancer cells reflects estrogen chemical carcinogenesis and therefore will be predictive for BT-SERM and NO modulating treatments that will attenuate tumorigenesis in experiments planned in Aim 3. In Aim 3, the ACI rat, an established model for estrogen-induced mammary carcinogenesis will be used to study the effect of one BT-SERM and NO modulation on carcinogenesis and tumor regression. PUBLIC HEALTH RELEVANCE: SERMs are a drug class used for postmenopausal syndromes and for prevention and therapy of estrogen dependent breast cancer. Risk-benefit ratios associated with estrogen replacement therapy and side effects of SERMs may be associated with tissue levels of nitric oxide (NO). The importance of this drug class demands a better understanding of the interactions of SERMs, estrogens, and NO as the foundation for improved therapeutic agents.