Improving CDK 4/6 inhibition in the treatment of medulloblastoma

提案摘要 这项提案将开发CDK 4/6抑制剂治疗髓母细胞瘤，使用一种新的，纳米粒子 palbociclib制剂，在转基因髓母细胞瘤易感小鼠中进行体内研究，并与 OLIG 2抑制剂CT-179。髓母细胞瘤是小儿最常见的恶性脑肿瘤。新 髓母细胞瘤的治疗是必要的，因为目前的治疗与手术，放射和化疗失败， 20%的患者和幸存者存在神经认知损伤、生长缺陷和心理社会风险 损伤虽然髓母细胞瘤是一种异质性疾病，有四个亚组，所有亚组都有完整的 RB和需要CDK 4/6活性。因此，CyclinD 1/CDK 4/6/视网膜母细胞瘤通路是一个药物靶点 在髓母细胞瘤亚群中共享。我发现FDA的纳米颗粒配方- 获批的CDK 4/6抑制剂palbociclib与母体药物相比，全身毒性降低， 延长内源性SHH驱动的髓母细胞瘤转基因小鼠的生存期。在这里，我展示了 Palbociclib既产生了预期的RB磷酸化降低效应，也产生了意想不到的效应， 包括S期的持久延长和表达OLIG 2的干细胞的增加。 我现在建议在SA 1中定义S期改变的机制，并确定敏感和抗性 使用单细胞转录组学分析（scRNA-seq）、蛋白质印迹和 免疫组化这些研究将证明经典和非经典的作用机制， 确定可以在未来研究中针对的耐药机制。在SA 2中，我建议测试治疗方法 Palbociclib治疗与OLIG 2抑制剂CT-179联合治疗的疗效。临床实践表明， 作为单一药物使用的药物是治疗髓母细胞瘤的，目前所有的治疗方法都依赖于联合用药 的代理人。根据我的初步数据，合理选择了Palbociclib和CT-179的联合用药。 完成我的研究计划和培训计划将为我提供教学和体验式学习 各种各样的机会是从小鼠遗传学，到多维细胞计数分析， scRNA-seq数据的计算分析。这项培训将使我能够发展基本和翻译 研究技能，并建立作为一个创新的，独立的研究科学家的职业基础。

PROPOSAL ABSTRACT This proposal will develop CDK4/6 inhibitor therapy for medulloblastoma, using a novel, nanoparticle formulation of palbociclib, studied in vivo in transgenic medulloblastoma-prone mice and combining with the OLIG2 inhibitor CT-179. Medulloblastoma is the most common malignant pediatric brain tumor. New medulloblastoma treatments are needed because current therapy with surgery radiation and chemotherapy fails 20% of patients and leaves survivors at risk for neurocognitive injury, growth defects, and psychosocial impairment. While medulloblastoma is a heterogenous disease with four subgroups, all subgroups have intact RB and require CDK4/6 activity. The CyclinD1/CDK4/6/Retinoblastoma pathway is therefore a druggable target shared amongst the medulloblastoma subgroups. I have found that a nanoparticle formulation of the FDA- approved CDK 4/6 inhibitor palbociclib shows reduced systemic toxicity compared to the parent drug and can extend the survival of transgenic mice with endogenous, SHH-driven medulloblastoma. Here, I show that palbociclib produces both the expected effect of reduced RB phosphorylation and also unexpected effects, including a durable prolongation of S phase and an increase in OLIG2-expressing stem cells. I now propose in SA1 to define the mechanism of S phase alterations and identify sensitive and resistant populations of medulloblastoma cells, using single-cell transcriptomic analysis (scRNA-seq), western blot and immunohistochemistry. These studies will demonstrate canonical and non-canonical mechanisms of action, and identify mechanisms of resistance that can be targeted in future studies. In SA2, I propose to test the therapeutic efficacy of combining palbociclib therapy with the OLIG2 inhibitor CT-179. Clinical practice has shown that no drug used as a single agent is curative for medulloblastoma, and all current treatments depend on combinations of agents. The combination of palbociclib and CT-179 is rationally chosen based on my preliminary data. Completing my Research Proposal and Training Plan will provide me with didactic and experiential learning opportunities in a diverse range are approaches, from mouse genetics, to multi-dimensional cytometric assays, to computational analysis of scRNA-seq data. This training will allow me to develop basic and translational research skills and build a foundation for a career as an innovative, independent research scientist.