Chemosensitization of Glioblastoma by Propentofylline

摘要 胶质母细胞瘤（GBM）是中枢神经系统最常见的原发性肿瘤，治疗选择有限且疗效不佳 临床预后。标准护理治疗，包括手术切除、放射治疗和同步治疗 替莫唑胺 (TMZ) 治疗后辅以 TMZ 辅助治疗，可提高新诊断 GBM 的中位生存率 约 15 个月。肿瘤复发是由于肿瘤细胞对治疗产生耐药性所致；因此，治疗策略 需要提高肿瘤细胞对化疗的敏感性来改善患者的预后。 TROY (TNFRSF19) 是 TNF 受体超家族的成员，最近被发现可以影响 GBM 进展。简而言之，TROY 表达随着神经胶质瘤分级的增加而增加，并与 患者生存。 TROY 表达增加刺激 GBM 细胞在体外和体内迁移/侵袭 增加体外对 TMZ 或辐射的抵抗力，而 TROY 表达的敲低则抑制细胞侵袭， 增加对 TMZ 的敏感性，并延长小鼠患者来源的异种移植 (PDX) 模型的生存期。这些 其他研究表明 TROY 代表了 GBM 的潜在新治疗靶点。 丙茶碱 (PPF)，一种已在多种非 GBM 临床试验中进行研究的药物 适应症，下调 TROY，抑制 GBM 侵袭并增加体外和体内对 TMZ 的敏感性 和放射治疗。 PPF 表现出良好的药理学特征，包括良好的大脑分布 和有利的安全指标。重新利用 PPF 可以更快地进入临床试验，风险更低，成本也更低 新化学实体的传统药物开发途径。 该提案的主要目标是测试 PPF 使 GBM 对 TMZ 敏感的能力。次要目标 包括评估：TROY 对于 PPF 活动的必要性、PPF 诱导的 TROY 的作用机制 下调，以及 PPF 治疗和 TROY 表达对促肿瘤小胶质细胞的影响。 以下目标旨在回答这些问题。具体目标1：测试PPF的能力 使 TMZ 耐药 GBM 肿瘤对颅内 PDX 模型中的治疗敏感，并 同基因模型。 PPF 使 GBM 细胞对 TMZ 敏感的能力将在 5 种 TMZ 耐药性 PDX 中进行评估 小鼠模型和一种免疫活性同系模型。 IVIS 监测肿瘤生长、持续时间 生存以及肿瘤和肿瘤微环境的组织病理学和分子分析将 评价。具体目标 2：表征 PPF 的细胞和分子靶点以预测临床 反应能力。活细胞自动成像和分子技术将用于帮助定义细胞 和PPF的分子靶点。我们将测试 PPF 对 20 个人类 GBM PDX 的多样化组敏感的能力 代表不同分子和预后亚型的线，以 TMZ 离体治疗并评估效果 PPF 对小胶质细胞的体外影响。

SUMMARY Glioblastoma (GBM) is the most common primary tumor of the CNS with limited treatment options and a poor clinical prognosis. Standard of care treatment, including surgical resection, radiation therapy and concurrent temozolomide (TMZ) treatment followed by adjuvant TMZ, produces a median survival in newly diagnosed GBM of ~15 months. Tumor recurrence happens due to therapy resistant tumor cells; therefore, therapeutic strategies that improve tumor cell sensitivity to chemotherapy are needed to improve patient outcomes. TROY (TNFRSF19), a member of the TNF receptor superfamily, has recently been discovered to impact GBM progression. Briefly, TROY expression increases with increasing glial tumor grade and inversely correlates with patient survival. Increased expression of TROY stimulates GBM cell migration/invasion in vitro and in vivo and increases resistance to TMZ or radiation in vitro, while knockdown of TROY expression inhibits cell invasion, increases sensitivity to TMZ, and prolongs survival in a murine patient-derived xenograft (PDX) model. These and additional studies indicate that TROY represents a potential novel therapeutic target for GBM. Propentofylline (PPF), a drug that has been studied in numerous clinical trials for several non-GBM indications, downregulates TROY, inhibits GBM invasion and increases sensitivity in vitro and in vivo to TMZ and radiotherapy. PPF exhibits a well-characterized pharmacological profile, including good brain distribution and favorable safety metrics. Repurposing PPF could be faster to clinical trials, less risky and less costly than the traditional drug development pathway for new chemical entities. The primary goal of this proposal is to test the ability of PPF to sensitize GBM to TMZ. Secondary goals include assessing: the necessity of TROY for PPF activity, the mechanisms of action for PPF-induced TROY downregulation, and the impact of PPF treatment and TROY expression on tumor-promoting microglia. The following aims have been designed to answer these questions. Specific Aim 1: Test the ability of PPF to sensitize TMZ resistant GBM tumors to therapeutic treatment in intracranial PDX models and a syngeneic model. The ability of PPF to sensitize GBM cells to TMZ will be evaluated in five TMZ resistant PDX mouse models and one immunocompetent syngeneic model. IVIS-monitoring of tumor growth, duration of survival as well as histopathological and molecular analysis of tumor and tumor microenvironment will be evaluated. Specific Aim 2: Characterize the cellular and molecular targets of PPF to predict clinical responsiveness. Live-cell automated imaging and molecular techniques will be used to help define the cellular and molecular targets of PPF. We will test the ability of PPF to sensitize a diverse panel of 20 human GBM PDX lines, representing varied molecular and prognostic subtypes, to TMZ treatment ex vivo and assess the effects of PPF on microglia in vitro.