Dissecting and targeting oncogenic functions of PAK4 in high-risk rhabdomyosarcoma

项目总结/摘要 横纹肌肉瘤是儿童和青少年最常见的软组织肉瘤。总的来说， RMS的存活率约为65- 70%。然而，尽管加强了化疗， 治疗方案，转移性或复发性横纹肌肉瘤患者的长期结果仍然非常 总体生存率在20- 30%之间。因此，替代靶向治疗对于改善 患者结局。我们的建议将解决高风险的知识和治疗方面的重大差距。 横纹肌肉瘤RMS肿瘤在RAS/NF 1通路中有频繁的突变，并且在RAS/NF 1通路中有干扰。 受体酪氨酸激酶（RTK）/RAS/磷酸肌醇3-激酶（PI 3 K）信号传导轴，其与 高风险条件。丝氨酸/苏氨酸激酶的p21激活激酶（PAK）家族与致癌的 通过RTK和RAS激活的途径进行信号传导。下游PAK信号传导调节转移表型 和对治疗药物的抗性，从而使它们成为晚期癌症的有吸引力的靶点。基于广泛的 信息学、功能基因组学、生物化学相互作用组学和药理学数据表明PAK 4 调节内在和外在机制，包括选择性剪接（AS）和免疫调节信号， 有助于RMS进展。此外，使用高通量联合药物筛选，我们发现， 机制上合理的和临床上适用的与PAK 4抑制的协同治疗方案。的 我们计划的首要目标是获得对PAK 4介导的新机制的关键分子见解 并进一步探讨PAK 4靶向治疗RMS的潜力。我们将研究PAK 4作为 AS和PAK 4介导的下游转录组学和蛋白质组学特征的新调节剂， 通过使用我们广泛的高度相关的人类和同基因小鼠的库存， 临床前模型。我们假设PAK 4调节关键的内在和外在分子特征， RMS进展，PAK 4抑制剂与合理的靶向药物组合可以提供有效的新的 为这些高风险患者提供治疗方案。我们提出了三个独立的，但创新和新颖的 互补的目的是解决这个假设。目标1. PAK 4作为一种新的剪接调节蛋白的评价 激酶及其对RMS下游信号传导的直接影响。目标2. PAK 4在肿瘤调控中的作用 使用RMS的相关鼠临床前模型的微环境和治疗应用的鉴定 在我们的实验室里开发的。目标3。研究抑制PAK 4与以下药物组合的治疗潜力： 使用创新的离体3D肺转移模型和体内3D肺转移模型， 原位和转移性RMS模型。这些研究的完成将提供新的分子见解， RMS生物学和影响RMS治疗，提供新的治疗策略，可以迅速转向 治疗复发或转移性RMS的临床试验。

PROJECT SUMMARY/ABSTRACT Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children and adolescents. Overall, survival rates for RMS are approximately 65-70%. However, despite intensification of chemotherapeutic regimens, long-term outcomes for patients with metastatic or relapsed rhabdomyosarcoma remain extremely poor, with overall survival rates between 20-30%. Thus, alternative targeted therapies are essential for improving patient outcomes. Our proposal will address a significant gap in the knowledge and treatment of high-risk rhabdomyosarcoma. RMS tumors have frequent mutations in the RAS/NF1 pathway and perturbations in the receptor tyrosine kinases (RTK)/RAS/phosphoinositide 3-kinase (PI3K) signaling axis, which are associated with high-risk conditions. The p21-activated kinases (PAK) family of serine/threonine kinases intersects the oncogenic signaling by RTK and RAS-activated pathways. Downstream PAK signaling regulates metastatic phenotypes and resistance to therapeutics, thus making them attractive targets for advanced cancers. Based upon extensive informatic, functional genomic, biochemical interactome and pharmacological data we have evidence that PAK4 regulates intrinsic and extrinsic mechanisms, including alternative splicing(AS) and immune modulatory signals, that contributes to RMS progression. In addition, using high-throughput combination drug screens we identified mechanistically rational and clinically applicable synergistic therapeutic regimens with PAK4 inhibition. The overarching goals of our proposal are to gain critical molecular insights into novel PAK4-mediated mechanisms and further investigate the therapeutic potential of targeting PAK4 in RMS. We will examine PAK4’s role as a novel regulator of AS and PAK4-mediated downstream transcriptomic and proteomic signatures that contribute to RMS progression through the use of our extensive inventory of highly relevant human and syngeneic murine pre-clinical models. We hypothesize PAK4 regulates critical intrinsic and extrinsic molecular signatures vital for RMS progression, and PAK4 inhibitors in combination with rational targeted agents can provide effective novel therapeutic regimens for these high-risk patients. We propose three independent, yet innovative and novel complementary aims to address this hypothesis. Aim1. Evaluation of PAK4 as a novel splicing regulating protein kinase and its direct effects on downstream signaling in RMS. Aim 2. Role of PAK4 in modulating the tumor microenvironment and identification of therapeutic applications using relevant murine pre-clinical models of RMS developed in our lab. Aim3. Investigate the therapeutic potential of inhibiting PAK4 in combination with mechanistically rational targeted agents using innovative ex vivo 3D lung metastasis models and in vivo orthotopic and metastatic RMS models. Completion of these studies will provide novel molecular insights into RMS biology and impact RMS therapy by providing new therapeutic strategies that can be quickly moved towards clinical trials for the treatment of relapsed or metastatic RMS.