Parp Function in Prostate Cancer

项目总结 这项建议是建立在我们在上一个资助期中发现的一种新的 整合雄激素信号与ADP核糖化的前列腺癌细胞。这条路有 四个关键成分，雄激素受体(AR)，Parp7，Parp9和Dtx3L。我们发现， 途径涉及Parp7的AR诱导和Parp7，On的多位点单-ADP-核糖化 AR氨基末端区域的半胱氨酸。在这个途径中，Parp7作为ADP-核糖的写入者 而Parp9作为ADP-核糖阅读器，这些反应的结果是雄激素- AR-Dtx3L/Parp9复合体的依赖组装及其对AR活性的调节 转录因子。有了这个知识库，我们就可以解决重要的问题 关于该途径如何驱动前列腺癌细胞的生物学效应，以及Parp7是否是一种 在包括去势抵抗前列腺癌的模型中可操作的靶点 未得到满足的临床需求。在目标1中，我们将确定AR-Parp7通路和单-ADP- 用结构-功能实验研究核糖化对前列腺癌细胞成瘤的调控作用 它询问了四个组成部分中每一个的贡献。因为AR是唯一已知的 PARP7底物，我们将确定前列腺中的ADP-核糖蛋白质组 癌细胞识别额外的AR非依赖性途径，Parp7通过这些途径调节前列腺 癌细胞。在目标2中，我们将确定ADP-核糖写入和读取的分子基础 在AR-Parp7通路上。AR的Parp7ADP-核糖化是雄激素结合的AR所特有的， 我们有一个策略来确定AR的激动剂构象是如何产生的 允许ADP-核糖化的位点。AR将被用作研究读者的模型 Parp9大结构域的功能，特别是对选择性很重要的特征。在……里面 目的3我们确定前列腺癌细胞对一类Parp7抑制剂的易感性， 并测试该抑制剂是否能促进前列腺癌的生长和转移。我们的研究将受益于 由国内和国际科学家组成的团队做出的重大贡献 前列腺癌模型，蛋白质组标度质谱学，合成肽化学，PARP 结构生物学，以及PARP抑制剂的实施。我们的总体假设是 通过Parp7转导的雄激素信号同时调节基因组和非基因组 选择性阻断Parp7将抑制前列腺癌的发生。如果 假设是正确的，我们的工作将确定Parp7作为前列腺癌的新治疗靶点 并扩展基于PARP抑制剂的治疗工具箱。

PROJECT SUMMARY This proposal builds upon our discovery in the previous funding period of a novel pathway in prostate cancer cells that integrates androgen signaling with ADP-ribosylation. The pathway has four key components, the androgen receptor (AR), Parp7, Parp9 and Dtx3L. We found that the pathway involves AR induction of Parp7 and multi-site mono-ADP-ribosylation by Parp7, on cysteines in the AR amino-terminal domain. In this pathway, Parp7 acts as an ADP-ribose writer and Parp9 serves as an ADP-ribose reader, and the outcome of these reactions is androgen- dependent assembly of an AR-Dtx3L/Parp9 complex and regulation of AR activity as a transcription factor. With this knowledge base, we are positioned to tackle important questions on how the pathway drives biological effects in prostate cancer cells, and whether Parp7 is an actionable target in models that include castrate-resistant prostate cancer where there is an unmet clinical need. In Aim 1, we will determine how the AR-Parp7 pathway and mono-ADP- ribosylation regulate tumorigenesis in prostate cancer cells using structure-function experiments that interrogate the contributions of each of the four components. Since AR is the only known Parp7 substrate in prostate cancer cells, we will define the ADP-ribosyl-proteome in prostate cancer cells to identify additional, AR-independent pathways, by which Parp7 regulates prostate cancer cells. In Aim 2 we will determine the molecular basis for ADP-ribose writing and reading on the AR-Parp7 pathway. Parp7 ADP-ribosylation of AR is specific for androgen-bound AR, and we have a strategy in place to determine how the agonist conformation of AR generates sites that are permissive for ADP-ribosylation. AR will be used as a model to study the reader function of Parp9 macrodomains, in particular, the features that are important for selectivity. In Aim 3 we determine the vulnerability of prostate cancer cells to a first-in-class Parp7 inhibitor, and test whether the inhibitor can prostate growth and metastasis. Our study will benefit from significant contributions from a team of national and international scientists with expertise in prostate cancer models, proteome-scale mass spectrometry, synthetic peptide chemistry, Parp structural biology, and implementation of Parp inhibitors. Our overall hypothesis is that androgen signaling transduced through Parp7 regulates both genomic and non-genomic pathways, and that selective blockade of Parp7 will inhibit prostate tumorigenesis. If the hypothesis is correct, our work will identify Parp7 as a new therapeutic target in prostate cancer and expand the toolbox of Parp inhibitor-based treatments.