MECHANISMS OF ESTROGEN RECEPTOR REGULATION

雌激素受体调节机制

基本信息

批准号：
7352699
负责人：
RONALD J WEIGEL
金额：
$ 23.14万
依托单位：
UNIVERSITY OF IOWA
依托单位国家：
美国
项目类别：
财政年份：
2006
资助国家：
美国
起止时间：
2006-02-01 至 2010-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7352699
关键词：
Address Alleles Binding Binding Sites Breast Cancer Cell Cell fusion Cell model Cells Chemicals Chromatin Chromatin Structure Cultured Cells Epigenetic Process Estrogen Receptor alpha Estrogen Receptors Future Gene Expression Gene Targeting Genes Genetic Transcription Goals Histone Acetylation Hormone Responsive Hormones Human In Vitro Location MCF7 cell Maps Mediating Methylation Modification Nucleic Acid Regulatory Sequences Pathway interactions Peptides Phenotype Physiological Processes Protein Overexpression Protein p53 Proteolysis Regulation Regulatory Element Repression Research Personnel Role Site Small Interfering RNA TP53 gene Transcription Factor AP-2 Alpha Tumor Suppressor Proteins base crosslink hormone regulation inhibitor/antagonist interest malignant breast neoplasm novel therapeutics promoter response transcription factor

项目摘要

The expression of estrogen receptor-alpha (ERa) is critical for establishing the hormone responsive phenotype of breast cancers. Functional promoter analysis and hypersensitive site mapping identified the AP2y transcription factor as a regulator of ERa expression and confirmed the location of AP2 regulatory sites in the human ERa gene promoter. Eliminating AP2y expression in ERa-positive cells using siRNA significantly down-regulates the expression of ERa and ERa-target genes. We conclude that AP2y is a key regulator of ERa expression in hormone responsive breast cancer cells. Epigenetic alterations involving methylation and histone acetylation have also been shown to contribute to the control of ERa gene expression. We hypothesize that epigenetic changes involving the AP2 regulatory element may provide an additional mechanism to regulate expression from the ERa promoter. Furthermore, we have identified an interaction between AP2 factors and the tumor suppressor protein p53 and there is substantial evidence showing that overexpression of p53 is capable of inhibiting the transcriptional activity of AP2. Hence, the interaction between AP2 factors and p53 represents another potential mechanism regulating the expression of ERa and may explain the finding that breast cancers with p53 overexpression are usually ERa-negative. Herein we propose to define the mechanisms regulating AP2-mediated activation of ERa and to determine the physiologic processes of hormone response controlled by AP2y. To accomplish this goal we propose to analyze the parameters of hormone response controlled by AP2y in MCF7 cells. We will define the functional domains of AP2 factors that are necessary for regulation of ERa. Using cell models of ERa repression and reactivation, we will determine if epigenetic alterations of the AP2 regulatory region contribute to control of ERa expression. We will investigate the mechanisms of p53-mediated repression of ERa by determining if p53 alters AP2y activity or chromatin interaction. The role of p53 in regulating ERa will be investigated by examining p53 alleles recovered from breast cancers for mutationsthat disrupt the AP2-interaction domain. We will define residues that are critical for the interaction between AP2 and p53 and generate antagonists as a prelude to developing a specific inhibitor of the AP2-p53 interaction. In the future it may be possible to develop a novel therapeutic to induce hormone response in breast cancers by specifically targeting the AP2 pathway.

雌激素受体-α (ERa) 的表达对于建立激素反应至关重要乳腺癌的表型。功能启动子分析和超敏感位点定位确定了 AP2y转录因子作为ERa表达的调节因子并确认了AP2调节位点的位置位于人类 ERa 基因启动子中。使用 siRNA 消除 ERa 阳性细胞中的 AP2y 表达显着下调 ERa 和 ERa 靶基因的表达。我们得出结论 AP2y 是关键激素反应性乳腺癌细胞中 ERa 表达的调节因子。表观遗传改变涉及甲基化和组蛋白乙酰化也被证明有助于 ERa 基因的控制表达。我们假设涉及 AP2 调控元件的表观遗传变化可能提供调节 ERa 启动子表达的额外机制。此外，我们还确定了一个 AP2 因子与抑癌蛋白 p53 之间存在相互作用，并且有大量证据显示p53的过度表达能够抑制AP2的转录活性。因此， AP2 因子和 p53 之间的相互作用代表了调节表达的另一种潜在机制可能解释了 p53 过度表达的乳腺癌通常是 ERa 阴性的这一发现。在此，我们建议定义调节 AP2 介导的 ERa 激活的机制并确定 AP2y 控制的激素反应的生理过程。为了实现这一目标，我们建议分析MCF7细胞中AP2y控制的激素反应参数。我们将定义 AP2 因子的功能域是 ERa 调节所必需的。使用 ERa 的细胞模型抑制和重新激活，我们将确定 AP2 调节区的表观遗传改变是否有助于控制 ERa 表达。我们将研究 p53 介导的抑制机制 ERa 通过确定 p53 是否改变 AP2y 活性或染色质相互作用。 p53在调节ERa中的作用将通过检查从乳腺癌中回收的 p53 等位基因来研究是否存在破坏 AP2-相互作用域。我们将定义对 AP2 和 p53 之间相互作用至关重要的残基并产生拮抗剂，作为开发 AP2-p53 相互作用的特异性抑制剂的前奏。在未来可能会开发出一种新的疗法来诱导乳腺癌的激素反应专门针对 AP2 通路。