Novel genomic mechanism for ligand-dependent transcription by androgen receptor

雄激素受体配体依赖性转录的新基因组机制

• 批准号: 9489287
• 负责人: Qianben Wang
• 金额: $ 32.07万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-06-01 至 2021-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9489287
• 关键词: Affect; Agonist; Androgen Analogues; Androgen Antagonists; Androgen Receptor; Binding; Biochemical; ChIP-seq; Chromatin; Clinical; Complex; DNA; DNA receptor; DNase I hypersensitive sites sequencing; Data; Data Analyses; Development; Disease; Elements; Environment; Epigenetic Process; Exonuclease; Foundations; Future; Gene Expression; Gene Targeting; Generations; Genes; Genetic Transcription; Genomic approach; Genomics; HSP 90 inhibition; Histones; Hormone Responsive; Immunoprecipitation; Impairment; Investigation; Ligands; Location; Malignant Neoplasms; Malignant neoplasm of prostate; Mass Spectrum Analysis; Nuclear Hormone Receptors; Nuclear Receptors; Nucleic Acid Regulatory Sequences; Nucleosomes; Oncogenes; Pharmacology; Play; Positioning Attribute; Prostate Cancer therapy; Proteins; Proteomics; Regulator Genes; Resistance; Resolution; Role; Stanolone; Technology; Testing; Tissues; Treatment Efficacy; Treatment Failure; anticancer activity; base; cell growth; chromatin immunoprecipitation; epigenomics; improved; inhibitor/antagonist; member; novel; novel strategies; novel therapeutics; prostate cancer cell; prostate cancer progression; receptor binding; receptor function; recruit; targeted treatment; transcription factor; transcriptome sequencing

Novel genomic mechanism for ligand-dependent transcription by androgen receptor Project Summary/Abstract Androgen receptor (AR) is a member of nuclear hormone receptor (NR) superfamily that binds to cognate hormone responsive elements (HREs) and regulates target gene expression in an endogenous ligand (agonist)-inducible manner in diverse tissues. As AR plays a key role in the onset and progression of prostate cancer, numerous synthetic AR antagonists have been developed to inhibit the action of endogenous AR ligands. A prominent example is enzalutamide (Xtandi®), a second-generation AR antagonist showing strong anti-cancer activity for prostate cancer. However, intrinsic or acquired resistance to enzalutamide, and all available AR antagonists, occurs leading to treatment failure. Thus, therapeutic efficacy of current AR antagonists needs to be improved. Elucidation of genomic mechanisms underlying antagonist-liganded AR function is critically important in order to improve AR-targeted therapy. In preliminary studies, we have defined the first high-resolution (motif-resolution) agonist- and antagonist-liganded AR cistromes in prostate cancer cells by using a novel chromatin immunoprecipitation-exonuclease (ChIP-exo) approach. Unexpectedly, we found that AR bound to natural agonist (dihydrotestosterone, DHT) and antagonist (enzalutamide) recognizes distinctly different DNA motifs on chromatin (termed “DNA motif switching”). Surprisingly, integrated ChIP-exo and RNA-seq analysis found that enzalutamide-liganded AR, bound to a novel AR binding motif, significantly affects global, cancer-relevant transcription. By combining our novel ChIP-exo genomic approach with other epigenomic, proteomic and biochemical approaches, we further found that enzalutamide-liganded AR interacts with specific collaborating transcription factors (e.g. FoxA1) and non-DNA binding coregulators (e.g. Hsp90) on specific active cis-regulatory regions. Importantly, pharmacological Hsp90 inhibition significantly decreases expression of enzalutamide-liganded AR target genes (e.g. cancer promoting genes GR and CD55) and enhances cell growth inhibitory effect of enzalutamide. Based on these compelling data, we hypothesize that DNA motif switching is a novel genomic mechanism underlying antagonist-dependent, cancer-relevant transcription by antagonist-liganded AR transcription complex. Our specific aims are to: 1) determine whether specific transcription factors and epigenetic features globally facilitate AR DNA motif switching; and 2) investigate how antagonist-liganded AR binding regulates expression of cancer-relevant genes. By significantly enhancing our understanding of how antagonist-regulated transcription by AR is controlled at the genomic level, this study will lay the foundation for future development of improved AR-targeted therapy.

雄激素接收器配体转录的新型基因组机制 项目摘要/摘要 雄激素受体（AR）是核马受体（NR）超家族的成员 马酮反应元件（HRE）并调节内源配体中的靶基因表达 （激动剂）在多样性组织中可诱导的方式。由于AR在前列腺的发作和进展中起关键作用 癌症，已经开发出许多合成AR拮抗剂来抑制内源性AR的作用 配体。一个突出的例子是enzalutamide（Xtandi®），这是第二代AR拮抗剂表现强的 前列腺癌的抗癌活性。但是，内在或获得的对恩扎拉酰胺的抗性，以及所有 可用的AR拮抗剂会导致治疗失败。这，当前AR的治疗效率 拮抗剂需要改善。阐明基因组机制的基因组机制 功能至关重要，以改善靶向AR靶向治疗。在初步研究中，我们定义了 前列腺癌中的第一个高分辨率（分辨率）激动剂和拮抗剂AR cistromes 通过使用新型的染色质免疫沉淀 - 核酸酶（CHIP-EXO）方法。出乎意料的是，我们 发现与天然激动剂（二氢睾丸激素，DHT）和拮抗剂（enzalutamide）结合的AR识别 染色质上不同不同的DNA基序（称为“ DNA基序切换”）。令人惊讶的是，集成的芯片exo RNA-seq分析发现，与新型AR结合基序结合的Enzalutamide-liganded AR显着 影响全球与癌症相关的转录。通过将我们的新型芯片-EXO基因组方法与其他 表观基因组，蛋白质组学和生化方法，我们进一步发现enzalutamide-liganded AR相互作用 具有特定的协作转录因子（例如FOXA1）和非DNA结合核心调节剂（例如HSP90） 特定的主动顺式调节区域。重要的是，药物HSP90抑制作用显着降低 enzalutamide-liganded AR靶基因的表达（例如促进基因GR和CD55的癌症）和 增强细胞生长的抑制作用。基于这些引人入胜的数据，我们假设 DNA基序转换是一种新型的基因组机制，依赖性拮抗剂与癌症相关 通过拮抗剂结合的AR转录复合物转录。我们的具体目的是：1）确定是否 特定的转录因子和表观遗传特征在全球范围内促进AR DNA基序转换；和2） 研究拮抗剂结合的AR结合如何调节癌症相关基因的表达。显着 增强我们对在基因组中控制AR的拮抗剂调节转录的理解 水平，这项研究将为未来改进的AR靶向疗法的发展奠定基础。