Targeting purine biosynthesis to radiosensitize glioblastoma

项目摘要/摘要 胶质母细胞瘤(GBM)是最常见的侵袭性原发脑肿瘤，平均致死率为 存活时间约为1.5年。与手术和化疗一样，放射治疗(RT)是近 在多个随机试验中，每个患有GBM的患者都反复提高了患者的存活率。尽管如此，80%的 大剂量RT野内可见GBMS复发。因此，迫切需要制定战略来克服大流行病。 RT抵抗，以进一步改善患者的预后。 GBM细胞表现出严重的癌症特异性代谢异常，包括嘌呤合成增加，以补充燃料 扩散、侵袭和存活。利用携带颅内原位患者脑肿瘤的小鼠，我的 研究已经证实，嘌呤合成增加的代谢表型也介导了对 RT通过促进RT诱导的DNA损伤修复而在GBM中发挥作用。这种嘌呤介导的RT耐药可以是 可通过霉酚酸酯(MMF)治疗，MMF是FDA批准的一种中枢神经系统穿透抑制药 嘌呤生物合成。 在这个研究方案中，我将确定RT反应和嘌呤合成是如何在 GBM。通过使用各种尖端代谢组学技术和患者衍生的GBM模型，我将1) 定义GBM用来产生嘌呤的生物合成途径，以及2)确定RT反应机制 通过这种方式，GBM增加了嘌呤水平，以抵抗RT诱导的DNA损伤。 这里提出的实验结果将扩大我们对肿瘤如何调节的理解 代谢促进治疗耐药，告知如何将代谢抑制剂与标准药物结合 疗法，并为密歇根大学针对嘌呤的临床试验奠定了机械基础 生物合成以增强GBM患者的RT。

Project Summary/Abstract Glioblastoma (GBM) is the most common aggressive primary brain tumor and is uniformly fatal with a median survival of around 1.5 years. Like surgery and chemotherapy, radiation (RT) is a critical treatment for nearly every patient with GBM and has repeatedly improved patient survival in multiple randomized trials. Still, 80% of GBMs recur within the high dose RT field. Thus, there is a critical need to develop strategies to overcome GBM RT resistance to further improve patient outcomes. GBM cells exhibit profound cancer-specific metabolic abnormalities, including elevated purine synthesis, to fuel proliferation, invasion and survival. Using mice bearing intracranial orthotopic patient-derived brain tumors, my research has established that the metabolic phenotype of elevated purine synthesis also mediates resistance to RT in GBM by promoting the repair of RT-induced DNA damage. This purine-mediated RT resistance can be overcome by treatment with mycophenolate mofetil (MMF), an FDA-approved and CNS-penetrant inhibitor of purine biosynthesis. In this research proposal I will determine how the RT response and purine synthesis regulate one another in GBM. By employing a variety of cutting-edge metabolomic techniques and patient-derived GBM models, I will 1) define the biosynthetic pathway GBMs use to generate purines, and 2) determine the RT response mechanism by which GBMs increase purine levels to resist RT-induced DNA damage. Findings from the experiments proposed here will expand our understanding of how tumors modulate metabolism to promote therapeutic resistance, inform how to combine metabolic inhibitors with standard therapies, and lay the mechanistic groundwork for clinical trials at the University of Michigan that targeting purine biosynthesis to augment RT in GBM patients.