Mechanisms of Variant ER-alpha Function in Breast Cancer

项目摘要/摘要 雌激素受体-α(ER)是核受体转录因子家族的成员，它推动 乳腺癌细胞的增殖，在大多数乳腺癌中都有表达。表达的肿瘤 ER是乳腺癌相关死亡人数最多的原因。在瞄准配基的同时- 受体功能依赖是乳腺癌临床治疗的成功途径 可以通过其他方式激活。ER的这种替代活性可以促进配体无关的性质 而我们对这一活动的缺乏理解为临床治疗耐药性的挑战创造了障碍。 我们发现，ER的磷酸化可以调控ER生物学的多个方面 在肿瘤细胞中，包括其命运和转录功能，在某些情况下导致配体独立 以及对治疗的抗拒。我们最近描述了一种全基因组DNA结合(即cstrome)分析 磷酸化ER，特别是Ser118处的磷酸化，并发现它具有独特的性质， 包括与发育转录因子GRHL2的新关联 自那以后，这一点已被认为在乳腺癌中起到了作用。基于这些新的发现和其他 初步数据，我们假设pS118和GRHL2识别ER的选择性活性 对于耐药肿瘤的生长是必要的。为了解决这一假设，我们开发了三个 研究领域。目的1利用我们对pS118ER和一个独特的患者肿瘤队列的周期分析 首次用样本定义ER+治疗耐药肿瘤中的pS118ER活性。AIM 2将测试 PS118ER和GRHL2在ER细胞生长和恶性表型中的需求 突变，一种治疗耐药的基因形式。此目标将使用新派生的CRISPR编辑单元格 模特们。AIM 3将使用新的DNA技术来询问pS118ER和GRHL2的机制 与DNA的相互作用，并开发DNA靶向选择性抑制剂。总而言之，这三个目标将 使用患者样本，体外和体内的方法和独特的技术来询问一个后 ER的翻译修饰变体有助于复发肿瘤中ER活性的异常。

PROJECT SUMMARY / ABSTRACT Estrogen receptor-alpha (ER), a member of the nuclear receptor family of transcription factors, drives proliferation of breast cancer cells and is expressed in the majority of breast cancers. Tumors that express ER account for the greatest number of breast cancer associated mortalities. While targeting the ligand- dependent functions of receptor is a successful approach in the clinical management of breast cancer, ER can be activated by other means. This alternative activity of ER can promote ligand-independent properties and our lack of understanding of this activity creates a barrier to the clinical challenge of therapy resistance. We have found that phosphorylation of ER can modulate the regulation of multiple aspects of ER biology in tumor cells, including its fate and transcriptional function, in some cases leading to ligand-independence and resistance to therapy. We recently described a genome-wide DNA binding (i.e. cistrome) analyses of phosphorylated ER, specifically phosphorylation at Ser 118, and found that it has unique properties, including a novel association with Grainyhead-like protein 2 (GRHL2), a developmental transcription factor that has since been recognized to play a role in breast cancer. Based on these novel findings and additional preliminary data, we hypothesize that pS118 and GRHL2 identify selective activities of ER that are necessary for growth of therapy-resistant tumors. Toward addressing this hypothesis, we developed three lines of research. Aim 1 exploits our cistromic analysis of pS118ER and a unique cohort of patient tumor samples to define, for the first time, the pS118ER activity in ER+ therapy-resistant tumors. Aim 2 will test the requirement for pS118ER and GRHL2 in growth and malignant phenotypes in cells bearing ER mutations, a genetic form of therapy resistance. This aim will use newly derived CRISPR edited cell models. Aim 3 will use novel DNA technologies to interrogate mechanisms of pS118ER and GRHL2 interactions on DNA and to develop DNA-targeting selective inhibitors. Collectively, these three aims will employ patient samples, in vitro and in vivo approaches and unique technologies to interrogate how a post- translationally modified variant of ER contributes to the aberrant ER activity in recurrent tumors.