Therapeutic Targeting of WDR5 in the Glioblastoma Perivascular Niche

项目总结/摘要：胶质母细胞瘤（GBM）是一种由小的 一群自我更新的高度致瘤性细胞，称为GBM干细胞（GSC）。我们的长期目标是 通过更好地了解驱动这种疾病的生物学，找到GBM的改进疗法。gbm肿瘤 具有复杂的微环境，包括含有GSC的相对增殖的血管周围小生境 富含干细胞标志物SOX 2+，以及通过以下途径调节驻留GSC的独特缺氧生态位 低氧信号因子由于不同GBM肿瘤区域内的细胞与正常细胞显著不同， 我们认为，个体肿瘤微环境必须以独特的小生境特异性 治疗然而，目前的培养模型无法复制GSC的复杂微环境，限制了我们的研究。 研究和治疗GBM的能力。因此，我们开发了患者来源的GBM类器官， 受控的离体系统，其包含增殖和缺氧小生境，以及干细胞和 与在患者肿瘤中观察到的那些相似的非干细胞。我们开发了一种方法， 分离类器官培养物的小生境，并使用这些技术来执行第一个空间分辨功能 筛查任何实体瘤。我们的研究结果指出，表观遗传效应蛋白WDR 5是唯一的 对于在GBM类器官的增殖生态位中生长的GSC至关重要。本申请的目的是 阐明WDR 5在胶质母细胞瘤中的作用，并确定WDR 5活性的破坏是否可能导致 疗效为了实现这一点，我们将测试GSC需要WDR 5来维持的中心假设。 二价基因在增殖性肿瘤小生境内表达，并且WDR 5可以靶向 损害体内GBM生长。我们将通过执行以下具体目标来测试这一点：1） 确定WDR 5活性是否是小生境特异性GSC体内生长所需的，2）确定WDR 5是否产生 GBM中的胚胎干细胞样二价基因调控，以及3）确定WDR 5功能的靶向是否产生 在GBM临床前模型中的治疗益处。拟议的研究是一项创新的首创性研究 这将验证针对特定生态位的靶向筛选和药物鉴定的可行性和有效性。这 通过使用新的方法和可行的新方法来克服 这是一个实验性的屏障，可以跨越多种癌症类型。这个概念和实验框架可以应用于 可以揭示独特的微环境生物学，并可以允许合理设计 针对利基特异性靶点的联合疗法。这项工作的预期成果是了解 WDR 5在GBM生态位生物学中的作用及新型血脑屏障穿透剂WDR 5抑制剂的评价 原位脑肿瘤迫切需要开发新的治疗策略， 提高GBM患者的生存率。该提案将研究WDR 5在GBM中的机制作用 生物学，同时在高度准确的临床前模型中测试有前途的潜在治疗方法。

PROJECT SUMMARY / ABSTRACT: Glioblastoma (GBM) is a uniformly fatal brain cancer driven by a small population of self-renewing, highly tumorigenic cells termed GBM stem cells (GSCs). Our long-term goal is to find improved therapeutics for GBM by better understanding the biology that drives this disease. GBM tumors have a complex microenvironment including a relatively proliferative perivascular niche containing GSCs enriched for the stem cell marker SOX2+, and a distinct hypoxic niche that regulates resident GSCs through hypoxic signaling factors. Because the cells within distinct GBM tumor regions are remarkably different from each other, we believe that individual tumor microenvironments must be targeted with unique niche-specific therapies. However, current culture models fail to replicate the complex microenvironments of GSCs, limiting our ability to study and therapeutically target GBM. We therefore developed patient-derived GBM organoids, a controlled ex-vivo system that contains both proliferative and hypoxic niches, as well as gradients of stem and non-stem cells similar to those observed in patient tumors. We developed methods to 3-dimensionally label the separate niches of organoid cultures and used these techniques to perform the first spatially-resolved functional screen in any solid tumor. Our results pinpointed the epigenetic effector protein WDR5 as being uniquely essential to GSCs growing in the proliferative niche of GBM organoids. The objective of this application is to illuminate the roles of WDR5 in glioblastoma and determine whether disruption of WDR5 activity may have therapeutic efficacy. To achieve this, we will test the central hypothesis that GSCs require WDR5 to maintain bivalent gene expression within proliferative tumor niches, and that WDR5 can be targeted to compromise GBM growth in vivo. We will test this through execution of the following specific Aims: 1) determine if WDR5 activity is required for niche-specific GSC growth in vivo, 2) determine if WDR5 creates embryonic stem-cell-like bivalent gene regulation in GBM, and 3) determine if targeting of WDR5 function yields a therapeutic benefit in GBM preclinical models. The proposed research is an innovative first-of-its-kind study that will verify the feasibility and efficacy of niche-specific targeted screening and drug identification. This represents a significant advancement by using novel methodology and feasible new approaches to overcome an experimental barrier across many cancer types. This conceptual and experimental framework can be applied to a wide range of cancers, can unmask unique microenvironmental biology, and can allow rationally designed combination therapies against niche-specific targets. The expected outcome of this work is an understanding of the roles of WDR5 in GBM niche biology and evaluation of a novel blood-brain-barrier penetrant WDR5 inhibitor in orthotopic brain tumors. There is an urgent need to develop novel therapeutic strategies that significantly improve the survival of GBM patients. This proposal will investigate the mechanistic role of WDR5 in GBM biology, while simultaneously testing a promising potential therapeutic in highly accurate preclinical models.