Therapeutically targeting cancer cell motility

 描述(由申请人提供)： 前列腺癌(PCa)的死亡是由转移瘤的形成引起的。这对美国退伍军人来说是一个重大问题。因此，推动转移发展的过程，如细胞运动性增加，代表着高价值的治疗靶点。所有选择性靶向细胞运动和随之而来的转移的尝试都失败了。我们通过设计一种独特的策略来解决这个棘手而重要的问题，该策略使用小化学物质作为高度精炼的探针，以确定新的和重要的生物调控位点。这导致我们合成了探针KBU2046，它抑制了热休克蛋白90β上Ser226的磷酸化。Ser226的磷酸化驱动细胞侵袭，并介导KBU2046的抗侵袭效应。当口服时，KBU2046在NM浓度下抑制小鼠的人前列腺癌转移。了解到HSP90的伴侣作用维持雄激素受体(AR)的功能状态，我们进一步证明了KBU2046介导的HSP90功能中断抑制了AR信号和AR驱动的细胞生长。最后，全面的临床前毒性和药理学研究都支持KBU2046作为一种药物在人类身上具有很高的活性潜力。我们假设我们的化学探针策略已经确定HSP90KBU2046的磷酸化是一种新的和选择性的调节转移进展的机制，KBU2046的疗效至少部分归因于调节客户蛋白与HSP90β结合，导致Ser226磷酸化状态的改变，并且这一策略为抑制人类的β转移提供了一条可行的途径。目的1.研究KBU2046影响客户蛋白结合和Ser226磷酸化的分子机制。KBU2046不直接抑制激酶功能。它改变了客户蛋白与热休克蛋白90β的结合，并且似乎是通过稳定热休克蛋白90β/CDC37异源复合体来实现的。研究将充分表征KBU2046诱导的客户蛋白与热休克蛋白90β结合的变化，并将继续评估它们如何影响Ser226磷酸化状态和细胞运动。目的2.评价KBU2046在临床相关的人PCa小鼠异种移植模型中的疗效。目的研究KBU2046是否能提高激素治疗的疗效，并延缓对激素治疗的耐药性的出现。Aim 2B的实验建立在我们最近发现KBU2046选择性抑制骨连接蛋白表达的基础上。Osteonectin是一种细胞外基质蛋白，已被证明可促进人前列腺癌的转移。我们假设KBU2046将阻断PCA细胞向骨的扩散，并将使用转移的心脏内注射模型进行测试。冲击力。研究将增加我们对癌细胞运动和转移的基本生物学的理解，并将向我们提供在人类中调节它的最佳方法。

 DESCRIPTION (provided by applicant): Prostate cancer (PCa) mortality is caused by the formation of metastases. This is a major problem for US veterans. Processes that drive the development of metastases, such as increased cell motility, therefore represent high value therapeutic targets. All attempts to selectively therapeutically target cell motility and consequent metastasis have failed. We approached this intractable and important problem by designing a unique strategy that used small chemicals as highly refined probes to identify novel and important biological regulatory sites. This led us to synthesize the probe, KBU2046, which inhibits phosphorylation of Ser226 on HSP90β. Phosphorylation of Ser226 drives cell invasion and mediates KBU2046 anti-invasion efficacy. When administered orally, KBU2046 inhibits human PCa metastasis in mice at nM concentrations. Knowing that HSP90 chaperone action maintains androgen receptor (AR) in its functional state, we went on to demonstrate that KBU2046-mediated disruption of HSP90 function inhibits AR signaling and AR-driven cell growth. Finally, comprehensive preclinical toxicity and pharmacology studies all support that KBU2046, as a drug, will have a high potential for activity in humans. We hypothesize that our chemical probe strategy has identified modulation of HSP90β Ser226 phosphorylation as a novel and selective mechanism regulating metastatic progression, that KBU2046 efficacy is due, at least in part, to modulation of client protein binding to HSP90β, resulting in changes in Ser226 phosphorylation status, and that this strategy provides a viable pathway for inhibiting PCa metastasis in humans. Aim 1. Characterize the molecular mechanism by which KBU2046 affects client protein binding and Ser226 phosphorylation. KBU2046 does not directly inhibit kinase function. It alters binding of client proteins to HSP90β, and appears to do so through stabilization of the HSP90β/CDC37 heterocomplex. Studies will fully characterize KBU2046 induced changes in client protein binding to HSP90β, and will go on to assess how they affect Ser226 phosphorylation status and cell motility. Aim 2. Evaluate KBU2046 efficacy in clinically relevant human PCa murine xenograft models. Aim 2A examines whether KBU2046 enhances the efficacy of hormone therapy, and delays emergence of resistance to it. Experiments in Aim 2B build upon our recent finding that KBU2046 selectively suppresses osteonectin expression. Osteonectin is an extracellular matrix protein, which has been shown to drive metastasis in human PCa. We hypothesize that KBU2046 will disrupt PCa cell dissemination to bone, and will test this using an intra-cardiac injection model of metastasis. Impact. Studies will increase our understanding of the basic biology of cancer cell motility and metastasis, and will inform us of the optimal means to modulate it in humans.