mRNA Polyadenylation in Prostate Cancer

项目摘要/摘要 前列腺癌是最常见的男性癌症，也是男性癌症的第二大病因。 死亡。前列腺癌细胞的一个关键生物学特性是它们的生长依赖于转录 一种叫做雄激素受体(AR)的因子。AR由雄激素激活，雄激素是一种男性荷尔蒙。 因此，对晚期前列腺癌患者的有效治疗方法是雄激素剥夺疗法， 它阻断雄激素的作用，抑制AR，并阻止前列腺癌细胞的生长。这个 雄激素剥夺疗法的局限性是前列腺癌细胞最终通过 允许AR重新激活的机制。这一致命阶段被称为耐阉割阶段。 前列腺癌(CRPC)。在这项提议中，我们已经确定了异常的mrna多腺苷基化作为一种调节。 促进CRPC中AR重新激活的机制。前-RNA的剪接是一个生物过程，受 核心剪接体和剪接因子。选择性信使核糖核酸剪接是蛋白质组的一种机制 多样化，使数十万种不同的蛋白质产品能够从 大约20,000个基因编码在人类基因组中。信使核糖核酸剪接是正常发育的关键 和组织动态平衡，已知在包括癌症在内的病理中会发生改变。一个关键的决策点 MRNA剪接是对最后一个外显子的识别，必须在3‘端切割该外显子才能添加 Poly(A)尾巴。这一过程被称为裂解和多聚腺苷酸化，由共识的结合来指导 最后一个外显子上的AAUAAA聚(A)位由一种称为切割和聚腺苷酸化的多肽复合体 特异性因子(CPSF)。我们的初步数据表明，CPSF的核心组成部分的表达 前列腺癌中复杂的表达改变与侵袭性疾病特征有关 包括转移。我们发现了一种新的前列腺癌调控机制，CPSF通过这种机制 复合体，介导AR基因内含子3中另一个AAUAAA聚(A)位点的利用，该位点 协调上游剪接事件，驱动多个成分活性AR变异蛋白的表达 在CRPC细胞中。本研究的假说是通过去调节CPSF使AR mRNA发生异常的多腺化。 ACTION促进多种AR变异体的表达，共同促进CRPC和对AR- 有针对性的治疗。为了验证这一假设，我们将1)研究CPSF复合体的表达和活性 临床前列腺癌的成分；2)阐明CPSF复合体结合AR的机制 前RNA和调节成分活性AR变异体的表达，以及3)核酸- 在治疗学的基础上，我们已经开发出阻断CPSF与AR基因位点的相互作用并抑制 AR变异蛋白的表达。总体而言，这项工作有望推进和连接mRNA的广泛领域 多聚腺苷酸化和AR信号转导，并提供预防或延迟CRPC的治疗机会。

PROJECT SUMMARY/ABSTRACT Prostate cancer is the most frequently diagnosed male cancer and second leading cause of male cancer deaths. A key biological property of prostate cancer cells is that their growth is dependent on a transcription factor called the androgen receptor (AR). The AR is activated by androgen, the male sex hormone. Accordingly, an effective treatment for patients with advanced prostate cancer is androgen deprivation therapy, which blocks the effects of androgens, inhibits the AR, and halts the growth of prostate cancer cells. The limitation of androgen deprivation therapy is that prostate cancer cells eventually develop resistance through mechanisms that allow AR to become reactivated. This lethal stage is referred to as castration-resistant prostate cancer (CRPC). In this proposal, we have identified aberrant mRNA polyadenylation as a regulatory mechanism that promotes AR re-activation in CRPC. Splicing of pre-RNA is a biological process regulated by the core spliceosome and splicing factors. Alternative mRNA splicing is a mechanism underlying proteomic diversification, enabling several hundreds of thousands of different protein products to be synthesized from the approximately 20,000 genes encoded in the human genome. mRNA splicing is critical for normal development and tissue homeostasis, and is known to be altered in pathologies including cancer. One key decision point in mRNA splicing is recognition of the last exon, which must be cleaved at the 3’ end before addition of the poly(A) tail. This process, termed cleavage and polyadenylation, is directed by binding of the consensus AAUAAA poly(A) site in the last exon by a polypeptide complex called the cleavage and polyadenylation specificity factor (CPSF). Our preliminary data demonstrates that expression of core components of the CPSF complex display altered expression in prostate cancer, which is associated with aggressive disease features including metastasis. We have uncovered a new prostate cancer regulatory mechanism whereby the CPSF complex, mediates utilization of an alternative AAUAAA poly(A) site in intron 3 of the AR gene, which coordinates upstream splicing events that drive expression of multiple constitutively active AR variant proteins in CRPC cells. The hypothesis of this study is that aberrant AR mRNA polyadenylation via de-regulated CPSF action promotes expression of multiple AR variants that collectively promote CRPC and resistance to AR- targeted therapies. To test this hypothesis, we will 1) study the expression and activity of CPSF complex components in clinical prostate cancer; 2) elucidate the mechanisms by which the CPSF complex binds AR pre-RNA and regulates expression of constitutively active AR variants, and 3) test efficacy of nucleic acid- based therapeutics we have developed that block CPSF interaction with the AR gene locus and inhibit expression of AR variant proteins. Overall, this work is expected to advance and link the broad fields of mRNA polyadenylation and AR signaling, and provide therapeutic opportunities to prevent or delay CRPC.