Role of NF90 in Prostate Cancer

摘要 前列腺癌是最常见的非皮肤癌，也是第三大致癌原因。 美国男性的死亡人数。虽然早期前列腺癌可以通过手术和放射治疗有效地治疗， 转移性前列腺癌仍然是一个挑战，雄激素剥夺疗法(ADT)是主流 治疗。虽然大多数高级PCA最初对ADT反应良好，但它们最终会发展为 抵抗，并变得耐阉割，称为CRPC。CRPC肿瘤不再需要雄激素来生长，但 通常仍然依赖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的激活可能为根除CRPC的有效策略提供重要的启示。 EZH2是多梳抑制复合体2(PRC2)的一个酶促亚单位，它催化组蛋白H3赖氨酸 27三甲基化抑制基因表达，这一作用可以有效地被酶EZH2靶向 抑制剂。最近的证据表明，EZH2在激活基因的过程中可能具有不依赖于PRC2的作用 表情。然而，对于靶基因是什么，EZH2如何激活它们，以及如何激活它们，仍然存在关键的差距 它们与EZH2的表观遗传作用协同工作，促进CRPC。我们的初步结果显示， AR是EZH2介导的转录激活的直接靶点。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和 具有致癌功能。然而，NF90在前列腺癌中的作用从未被研究过。我们假设 NF90与EZH2协同转录激活AR，促进CRPC进展。为了测试 在这些假设下，本文提出了三个具体目标。目标1将确定NF90与EZH2的相互作用方式 介导AR基因转录的蛋白质。目标2将确定NF90如何调节EZH2染色质 使用芯片序列分析和RNA-序列分析的重新招募和靶基因激活，以确定下游的特征 NF90的基因/通路，并检测NF90在原代PCa组织中的表达，以确定其 与EZH2表达及临床预后的相关性。最后，目标3将描述NF90在 前列腺癌的体内外实验，最重要的是测试一种新的联合疗法的疗效 利用酶促EZH2抑制剂GSK126和AR同时阻断EZH2双重作用的方法 苯扎鲁胺在PCa患者来源的异种移植(PDX)模型中的拮抗剂。

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.