Regulation of androgen receptor function by H3K4 methylation in prostate cancer

描述(申请人提供)：前列腺癌中H3K4甲基化对雄激素受体功能的调节项目摘要前列腺癌从雄激素依赖状态(ADPC)进化到耐阉割状态(CRPC)标志着疾病的致命进展。了解CRPC的发病机制和开发新的治疗方法仍然是迫切需要的。雄激素受体(AR)是一种配体依赖的转录因子，在CRPC中仍有表达和功能，但AR如何调控CRPC中的靶基因以及AR靶基因在CRPC中的功能作用尚不清楚。在初步研究中，我们发现在CRPC细胞模型中，AR选择性地与M期细胞周期基因的增强子区域(如UBE2C)结合，而在ADPC细胞模型中不结合，导致CRPC比ADPC有更高的M期基因表达和更快的生长。有趣的是，我们进一步发现，与ADPC相比，组蛋白H3赖氨酸4(H3K4)在M期基因增强子上的甲基化水平增加是CRPC中M期基因增强子选择性AR结合的潜在机制。然而，这些研究仅限于在一对CRPC/ADPC细胞模型中识别和表征几个增强子H3K4甲基化调节的AR靶基因。在这个建议中，我们假设增强子和启动子H3K4甲基化指导AR在全球调控参与CRPC生长和侵袭等关键过程的目标基因。我们的具体目标是：(1)确定增强子H3K4甲基化和AR是否在调节UBE2C表达中起因果作用，并研究UBE2C在各种CRPC细胞模型和体内肿瘤发生中的功能作用。UBE2C是一个直接增强子H3K4甲基化和AR共同调节的基因，在至少一个CRPC细胞模型的生长和侵袭以及体内肿瘤发生中发挥关键作用的假设将在这一目标中得到验证。(2)对CRPC细胞中H3K4甲基化和AR共调控基因进行全局性鉴定。假设H3K4me2的获得引导远端增强子结合的AR激活癌基因，而H3K4me2和/或H3K4me3的丢失导致增强子和/或启动子结合的AR介导的肿瘤抑制基因在CRPC中的沉默，这一假设将在这一目标中得到检验。(3)探讨前列腺癌组织中靶基因H3K4甲基化/AR调控的相关性。从AIMS 1和2获得的数据与人类前列腺癌相关的假设将在CRPC和ADPC样本中进行评估。

DESCRIPTION (provided by applicant): Regulation of androgen receptor function by H3K4 methylation in prostate cancer Project Summary The evolution of prostate cancer from an androgen-dependent state (ADPC) to one that is castration- resistant (CRPC) marks the lethal progression of the disease. Understanding the pathogenesis of CRPC and development of novel therapies for CRPC remains an urgent need. The androgen receptor (AR), a ligand-dependent transcription factor, is still expressed and functional in CRPC; however, how AR regulates target genes in CRPC and the functional roles of AR target genes in CRPC is poorly understood. In preliminary studies we have found that AR selectively binds to enhancer regions of M- phase cell cycle genes (e.g. UBE2C) in a CRPC cell model but not in an ADPC cell model, leading to higher M-phase gene expression and faster growth of CRPC than of ADPC. Interestingly, we further found that increased histone H3 lysine 4 (H3K4) methylation level on the M-phase gene enhancers is the underlying mechanism for selective AR binding at M-phase gene enhancers in CRPC compared with ADPC. However, these studies are limited to identifying and characterizing a few enhancer H3K4 methyaltion regulated AR target genes in a pair of CRPC/ADPC cell models. In this proposal we hypothesize that enhancer and promoter H3K4 methylation directs AR in the global regulation of target genes involved in critical processes such as growth and invasion in CRPC. Our specific aims are to: (1) To determine whether the enhancer H3K4 methylation and AR play a causal role in regulating UBE2C expression and to investigate the functional role of UBE2C in various CRPC cell models and in tumorigenesis in vivo. The hypothesis that UBE2C is a direct enhancer H3K4 methylation and AR co- regulated gene that plays a critical role in growth and invasion of at least a subset of CRPC cell models and in tumorigenesis in vivo will be tested in this aim. (2) To globally identify and characterize enhancer/promoter H3K4 methylation and AR co-regulated genes in CRPC cells. The hypothesis that gain of H3K4me2 directs distal enhancer-bound AR to activate oncogenes, whereas loss of H3K4me2 and/or H3K4me3 leads to enhancer- and/or promoter-bound AR-mediated silencing of tumor suppressor genes in CRPC will be tested in this aim. (3) To examine the relevance of H3K4 methylation/AR regulation of target genes in human prostate cancer samples. The hypothesis that the data obtained from Aims 1 and 2 is relevant to human prostate cancer will be evaluated in CRPC and ADPC samples in this aim.