Arsenic suppresses progesterone receptor signaling and promotes tamoxifen resistance and metastasis of ER+ breast cancer

总结 该项目的中心概念是暴露现有的雌激素受体（ER）， 孕激素（PR）阳性（ER+/PR+）乳腺肿瘤对重金属污染物的促进作用 缺乏PR表达和功能的肿瘤细胞的出现。而ER+/PR+乳腺癌 预后良好，对治疗反应良好，ER+/PR-不，往往进展到 高致死性复发性转移性疾病。因此，我们建议环境砷， 镉、铅或这些金属的混合物存在于颗粒空气污染和供水中， 对于ER+/PR+乳腺癌女性的成功治疗构成严重风险 促进这些肿瘤重编程为ER+/PR-表型。此外，我们发现， 重金属引起的表型重编程涉及细胞核氧化还原状态的变化。 随着活性氧（ROS）在细胞核中的增加， 诱导线粒体功能障碍，孕酮受体基因表达被抑制 释放表型重编程我们还发现， （线粒体）或在细胞核（作用部位）中逆转iAs对PR表达的抑制， 镉和铅，并在很大程度上重新敏感金属转化的乳腺癌细胞的抗- 一线选择性雌激素受体调节剂的肿瘤作用，通常最容易获得 治疗低收入和少数民族人口。因为，我们现在有FDA批准，以及， 新的专利化合物，以抑制肿瘤细胞核活性氧，这种策略可能会导致 急需的辅助疗法，以减轻一些最具破坏性的健康影响， 金属污染物对低收入和少数族裔乳腺癌患者的影响不成比例。 因此，本项目的目标是：1）确定核ROS驱动的表观遗传 重编程影响ER+/PR+肿瘤向治疗难治性ER+/PR-表型的转变; 2)确定抑制细胞核中的ROS是否恢复异种移植物中的治疗有效性 金属转化细胞的肿瘤模型; 3）确定FDA批准的药理学 线粒体ROS清除剂在使金属转化的肿瘤细胞对 SERMs。我们建议，找到药理学的方法来减轻一些有害的健康 暴露于重金属的影响可能是一个紧迫的短期解决方案，以减少 环境卫生差距。

SUMMARY The central concept in this project is that exposure of existing estrogen receptor (ER) and progesterone (PR) positive (ER+/PR+) breast tumors to heavy metal pollutants promotes the emergence of tumor cells that lack PR expression and function. While ER+/PR+ breast cancer have excellent prognosis and respond well to treatments, ER+/PR- do not and often progress to highly lethal recurrent metastatic disease. Hence, we propose that environmental arsenic, cadmium, lead or mixtures of these metals present in particulate air pollution and water supplies, poses a grave risk for the successful treatment of women with ER+/PR+ breast cancer via promoting the reprogramming of these tumors to ER+/PR- phenotypes. In addition, we found that phenotypic reprogramming by heavy metals involves changes in the cellular nuclear redox state. As reactive oxygen species (ROS) increase in the nucleus, vastly because of heavy-metal induced mitochondrial dysfunction, progesterone receptor gene expression is suppressed unleashing phenotypic reprogramming. We also found that quenching these ROS at the origin (mitochondria) or in the nucleus (site of action) reverses the suppression of PR expression by iAs, Cd and Pb and to a large extent resensitizes metal-transformed breast cancer cells to the anti- neoplastic action of first line selective estrogen receptor modulators, often the most accessible therapy for low income and minority populations. Since, we now have FDA-approved, as well as, novel proprietary compounds to suppress nuclear ROS in tumor cells, this strategy may lead to much needed adjuvant therapies to mitigate some of the most devastating health effects of heavy metal contaminants disproportionately affecting low income and minority breast cancer patients. Therefore the goals of this project are: 1) Determine how nuclear ROS-driven epigenetic reprogramming impacts ER+/PR+ tumor transitions to treatment refractory ER+/PR- phenotypes; 2) Determine if suppressing ROS in the nucleus restores treatment effectiveness in xenograft tumor models of metal-transformed cells; 3) Determine if FDA-approved pharmacologic mitochondrial ROS scavengers are effective in resensitizing metal-transformed tumor cells to SERMs. We propose that finding pharmacologic ways to mitigate some ofthe detrimental health effects of exposures to heavy metals may be an urgent short term solution to reduce environmental health disparities.