Targeting Adaptive Radioresistance of Glioblastoma

项目摘要 胶质母细胞瘤（GBM）是一种通过手术、放疗和化疗治疗的致命性脑癌。而 分次放射治疗（60 Gy，4-6周）可有效杀死许多癌细胞， 获得放射抗性并存活，导致肿瘤复发。了解潜在的机制 适应性辐射抗性可能导致克服辐射抗性的新的治疗方法。破译 辐射抗性机制，我们需要反映GBM遗传异质性的复杂模型， 包括干细胞群体，其被认为特别倾向于获得辐射抗性。直到 目前，只建立了有限的放射抗性模型，胶质瘤干细胞（GSC）的作用还不清楚， 得到了适当的检查。为了解决这一知识缺口，我开发了新的小鼠和 逐渐适应重复照射的人GSC。利用这些模型，我发现了一本小说 IGF 1诱导的N-cadherin信号传导驱动的耐药机制验证了我的方法。以识别 另外的辐射抗性基因，我在辐射抗性人类中进行了全基因组CRISPR文库筛选， GSC和发现新的候选基因，包括Syndecan 1（SDC 1）。我证明了SDC 1的表达是 在4种不同的放射抗性GSC系中增加，并与患者的恶性程度和不良结局相关 恶性胶质瘤（TCGA数据库）。在抗辐射GSC中敲除SDC 1恢复了辐射敏感性， 降低IGF 1 R表达并抑制IGF 1 R信号传导。如先前文献所示，SDC 1和 SDC 1与IGF 1 R之间存在相互作用，提示SDC 1与IGF 1 R可能是同一种辐射抗性的组成部分 通路基于这一基本原理，我假设增加SDC 1表达诱导适应性GBM 通过激活IGF 1 R信号传导产生辐射抗性;阻断SDC 1诱导的IGF 1 R激活将拮抗 辐射抗性和增加存活率。我将通过以下目的来检验我的假设：1）检验SDC 1如何 赋予GSC辐射抗性，2）确定SDC 1如何激活IGF 1 R信号传导，和3）评估功效 在小鼠模型中靶向SDC 1诱导的辐射抗性。我的项目是创新的，因为SDC 1的作用- IGF 1 R介导的信号传导在GSC辐射抗性从未被检查。该项目将导致 我的研究将为我未来的职业生涯奠定基础。我的职业规划是 系统地识别GSC中辐射抗性的驱动因素和相关信号传导机制。我有 作为神经外科医生和基础神经肿瘤学研究人员的双重背景，并进一步确保了 顾问和专业合作者的支持（见支持信）。成功完成该项目 将导致更好的治疗耐药GBM的治疗方法的发展，并推动我的研究。 过渡到神经肿瘤学的独立研究者。

PROJECT SUMMARY Glioblastoma (GBM) is a lethal brain cancer treated by surgery, radiotherapy, and chemotherapy. While fractionated radiation therapy (60Gy delivered over 4-6 weeks) is efficacious in killing many cancer cells, a subset gains radioresistance and survive, leading to tumor recurrence. Understanding the mechanisms underlying adaptive radioresistance may lead to new therapeutic approaches to overcome radioresistance. To decipher radioresistance mechanisms, we need sophisticated models that reflect the genetic heterogeneity of GBM, including the stem cell population, which is considered to be particularly prone to acquiring radioresistance. Till now, only limited radioresistance models have been developed and the role of glioma stem cells (GSCs) has not been properly examined. To address this gap in knowledge, I developed novel preclinical models of mouse and human GSCs that were progressively adapted to repeated irradiation. Using these models, I identified a novel resistance mechanism driven by IGF1-induced N-cadherin signaling validating my approach. To identify additional radioresistance genes, I performed a genome-wide CRISPR library screening in radioresistant human GSCs and found new candidate genes, including Syndecan 1 (SDC1). I showed that SDC1 expression is increased in 4 different radioresistant GSC lines and correlates with malignancy and poor outcome of patients with malignant glioma (TCGA database). Knockout of SDC1 in radioresistant GSCs restored radio-sensitivity, decreased IGF1R expression and suppressed IGF1R signaling. As prior literature has shown that SDC1 and IGF1R interact, these findings suggest that SDC1 and IGF1R might be components of the same radioresistance pathway. Based on this rationale, I hypothesize that increased SDC1 expression induces adaptive GBM radioresistance by activating IGF1R signaling; and that blocking SDC1-induced IGF1R activation will antagonize radioresistance and increase survival. I will test my hypothesis through the following aims: 1) examine how SDC1 confers GSC radioresistance, 2) determine how SDC1 activates IGF1R signaling, and 3) evaluate the efficacy of targeting SDC1-induced radioresistance in mouse models. My project is innovative because the role of SDC1- IGF1R-mediated signaling in GSC radioresistance has never been examined. This project will lead to the development of future my research and will become a foundation for my future career. My career plan is to systematically identify the drivers and related signaling mechanisms underlying radioresistance in GSCs. I have a dual background as a neurosurgeon and basic neuro-oncology researcher and have further secured the support of advisors and professional collaborators (see letters of support). Successful completion of this project will lead to the development of better therapies for the treatment of therapy-resistant GBM and propel my transition to an independent investigator in neuro-oncology.