Role of NF90 in Prostate Cancer

摘要 前列腺癌(Pca)是最常见的非皮肤癌，居第三位。 导致美国男性癌症死亡的原因。虽然早期前列腺癌可以有效地治疗 手术和放射治疗，转移性前列腺癌仍然是一个挑战和雄激素 剥夺疗法(ADT)是目前主要的治疗方法。尽管大多数高级PCA 最初对ADT反应良好，最终产生抵抗力并成为阉割- 抗性，称为CRPC。CRPC肿瘤不再需要雄激素来生长，但通常会残留 依赖于异常活跃的雄激素受体(AR)。了解以下机制： 这种雄激素非依赖性AR的激活可能为有效的策略提供重要的启示 根除CRPC。EZH2是多梳抑制复合体2(PRC2)的一个酶促亚单位 催化组蛋白H3赖氨酸27三甲基化以抑制基因表达，这一作用可以 成为酶促EZH2抑制剂的有效靶点。最近的证据表明，EZH2可能 在激活基因表达方面具有不依赖于PRC2的作用。然而，关键差距仍然存在，如 靶基因是什么，EZH2如何激活它们，以及它们如何与 EZH2在促进CRPC中的表观遗传学作用。我们的初步结果表明，AR是一种直接的 EZH2介导的转录激活的靶点。这种激活很可能是由EZH2- 交互作用共激活剂NF90。我们的初步数据进一步显示，NF90在 CRPC具有致癌功能。然而，NF90的作用从未被研究过 在PCA中。我们推测NF90与EZH2在AR和EZH2的转录激活中起协同作用。 促进CRPC进展。为了检验这些假设，我们提出了三个具体目标。目标 1将确定NF90如何与EZH2蛋白相互作用来介导AR基因的转录。目标2 将决定NF90如何调节EZH2染色质招募和靶基因激活 使用芯片序列分析和RNA-序列分析，表征NF90的下游基因/途径，以及 检测NF90在原发PCa组织中的表达以确定其与EZH2的相关性 表达和临床结果。最后，目标3将描述NF90在前列腺中的作用 在体外和体内癌症，最重要的是，测试一种新的组合的疗效 利用酶促EZH2同时阻断EZH2双重作用的治疗方法 前列腺癌患者来源的异种移植(PDX)中的GSK126抑制剂和AR拮抗剂苯扎鲁胺 模特们。

Summary Prostate cancer (PCa) is the most commonly diagnosed non-skin cancer and the third leading cause of cancer deaths in American men. While early-stage PCa can be effectively treated with surgery and radiation therapy, metastatic prostate cancer remains a challenge and androgen deprivation therapy (ADT) is the mainstay treatment. Although a majority of advanced PCa initially responds well to ADT, they ultimately develop resistance and become castration- resistant, called CRPC. CRPC tumors no longer need androgen to grow but often remain dependent on an aberrantly active androgen receptor (AR). Understanding the mechanisms to this androgen-independent AR activation may shed significant light on effective strategies to eradicate CRPC. EZH2 is an enzymatic subunit of the Polycomb Repressive Complex 2 (PRC2) that catalyzes histone H3 lysine 27 trimethylation to suppress gene expression, a role that can be effectively targeted by enzymatic EZH2 inhibitors. Recent evidence suggests that EZH2 may have PRC2-independent roles in activating gene expression. However, critical gaps remain as to what the target genes are, how EZH2 activates them, and how they work in concert with the epigenetic roles of EZH2 to promote CRPC. Our preliminary results showed that AR is a direct target of EZH2-mediated transcriptional activation. This activation is likely mediated by EZH2- interacting co-activator NF90. Our preliminary data further showed that NF90 is up-regulated in CRPC and exhibits oncogenic functions. The roles of NF90, however, have never been studied in PCa. We hypothesize that NF90 cooperates with EZH2 in transcriptional activation of AR and promotes CRPC progression. To test these hypotheses, three Specific Aims are proposed. Aim 1 will determine how NF90 interacts with EZH2 protein to mediate AR gene transcription. Aim 2 will determine how NF90 regulates EZH2 chromatin recruitment and target gene activation using ChIP-seq and RNA-seq assays, characterize downstream genes/pathways of NF90, and examine the expression of NF90 in primary PCa tissues to determine its correlation with EZH2 expression and clinical outcomes. Lastly, Aim 3 will characterize the roles of NF90 in prostate cancer in vitro and in vivo and, most importantly, test the efficacy of a new combinatorial therapeutic approach that simultaneously blocks the dual roles of EZH2 using enzymatic EZH2 inhibitor GSK126 and AR antagonist enzalutamide in PCa patient-derived xenograft (PDX) models.