Leveraging Temozolomide to Improve Treatment Efficacy of Immune Checkpoint Blockade in Glioblastoma

项目摘要 胶质母细胞瘤（GBM）是成人中最常见的原发性脑肿瘤，其特征在于侵袭性和侵袭性。 生长、显著的神经系统发病和最终死亡。替莫唑胺（TMZ）是最广泛的 一种公认的用于治疗GBM的化疗药物，尽管其在近50%的GBM中的疗效有限 患者因此，正在研究新的治疗方法，如免疫检查点抑制剂 对于GBM。免疫检查点是一种免疫抑制反应，它被肿瘤细胞吸收， 调节肿瘤抗原的T细胞靶向。针对程序性细胞死亡1（PD-1）的抗体允许T细胞 针对肿瘤新抗原的活化。这种方法在治疗实体瘤方面取得了巨大的成功。 组织肿瘤，现在正在测试对GBM的疗效。 这项研究计划将探讨剂量修饰的TMZ可能引发宿主T细胞的机制 和肿瘤新抗原表达以改善对PD-1免疫检查点阻断的应答。的理由 这一建议包括几个因素。首先，已经发现TMZ在组合使用时是有利的 由于在TMZ诱导的恢复期间宿主免疫的调节， 淋巴细胞减少症第二，免疫检查点抑制剂增强抗肿瘤T细胞对肿瘤的应答。 新抗原这种现象可以被利用，因为已知TMZ是致突变的，并导致 恶性胶质瘤中肿瘤新抗原负荷增加。第三，TMZ和PD-1联合阻断具有显著的抗肿瘤作用。 GBM的耐药表型的独特作用，因为这些肿瘤具有PD-L1表达的增加。 该提案将检验TMZ诱导宿主免疫和肿瘤遗传变化的假设， 导致对PD-1阻断的反应增加。这一假设将通过完成三个目标来检验。的 第一个目标是确定TMZ剂量和时间对宿主免疫变化的影响，以及对 PD-1阻断对GBM的疗效。将通过评价宿主上的PD-1和PD-L1表达来检验这一目的 在各种TMZ给药策略之后，对免疫细胞进行检测，并评估TMZ与PD-1组合的效果。 在同基因小鼠GBM模型中阻断宿主免疫功能和肿瘤浸润淋巴细胞。 第二个目的是评估剂量修饰的TMZ和PD-1阻断剂联合治疗耐药GBM的效用。 肿瘤的该目的将利用MGMT介导的TMZ抗性肿瘤模型来确定MGMT的功效。 用于GBM的抗性表型的组合治疗。最后的目的是探索机制， 剂量修饰的TMZ改变了肿瘤微环境并改变了对PD-1阻断的反应。的 实验将测试肿瘤基因突变和T细胞克隆性在对PD有反应的肿瘤中的差异， 1封锁相比，那些是耐药的。已经用TMZ预处理的肿瘤也将被治疗。 测试以确定治疗后肿瘤对免疫检查点阻断的反应如何不同 与TMZ对宿主免疫力的影响无关。在完成该提议时，PD-1阻断在 与剂量修饰的TMZ组合治疗GBM及其对GBM耐药表型的疗效将被评估。 明白这些结果有可能对GBM患者产生直接影响，因为目前正在进行 审判 这项拟议中的研究将由佛罗里达大学脑肿瘤研究所的拉赫曼博士进行 免疫治疗计划（UFBTIP）。她非常适合作为一个成功完成拟议的研究， 接受过神经肿瘤学专科培训的学术神经外科医生。她完成了一项研究 在布伦特雷诺兹博士和基诺内斯-伊诺霍萨博士的指导下，研究肿瘤干细胞的研究员 恶性胶质瘤和克服治疗耐药性。她完成了一个NIH资助的项目， 临床研究，并在临床和转化科学研究所获得硕士学位。 她的主要导师，杜安米切尔博士，是UFBTIP的主任，并有很强的校外记录 在研究恶性脑肿瘤的新型免疫平台方面获得了资金和成功。她的同事- 导师是Mark吉尔伯特博士和Amy Heimberger博士。吉尔伯特博士是神经肿瘤科主任， NCI他有相当丰富的临床试验经验，并领导了一项研究剂量强化TMZ的RTOG试验 目前正在领导一项临床试验，探索GBM的免疫检查点阻断。博士 Heimberger是MD安德森癌症中心的神经外科医生，在免疫治疗方面具有专长。 脑肿瘤和培养年轻科学家。除了指导她的研究，海姆伯格博士将帮助博士。 拉赫曼学习平衡临床神经外科实践与转化研究的努力。拉赫曼医生 有相当多的资金和充足的资源，通过UFBTIP实现她的研究目标。期间 在获奖期间，拉赫曼博士将完成一个全面的计划，发展成为一名临床科学家。这 计划将包括完成提案中概述的实验方案，完成课程工作， 研究方法和行为，并定期与她的顾问小组，其中包括高度 在神经外科、神经肿瘤学和肿瘤学方面有成就的临床科学家。她的职业目标包括 开发恶性胶质瘤的新疗法，了解如何克服肿瘤治疗耐药性 并改善神经胶质瘤患者的预后。这项职业发展计划将是重要的第一步， 实现这些目标。

PROJECT SUMMARY Glioblastoma (GBM) is the most common primary brain tumor in adults and is characterized by aggressive growth, significant neurologic morbidity and eventually death. Temozolomide (TMZ) is the most widely accepted chemotherapy drug used to treat GBM, although its efficacy is limited in almost 50% of GBM patients. Therefore, novel treatment approaches, such as immune checkpoint inhibitors are being investigated for GBM. Immune checkpoints are immune inhibitory responses that are co-opted by tumor cells to down regulate T cell targeting of tumor antigens. Antibodies to programmed cell death 1 (PD-1) allow for T cell activation against tumor neoantigens. This approach has had tremendous success in the treatment of solid tissue tumors and are now being tested for efficacy in GBM. This research proposal will investigate the mechanisms by which dose-modified TMZ may prime host T cells and tumor neoantigen expression to improve response to PD-1 immune checkpoint blockade. The rationale for this proposal include several factors. First, TMZ has been found to be advantageous when used in combination with immunotherapy for GBM due to conditioning of host immunity during the recovery from TMZ-induced lymphopenia. Second, immune checkpoint inhibitors enhance anti-tumor T cell responses against tumor neoantigens. This phenomenon can be leveraged since TMZ is known to be mutagenic and result in an increase burden of tumor neoantigens in malignant glioma. Third, combination TMZ and PD-1 blockade has a unique role for resistant phenotypes of GBM since these tumors have an increase in PD-L1 expression. This proposal will test the hypothesis that TMZ induces host immunologic and tumor genetic changes that will result in increased response to PD-1 blockade. This hypothesis will be tested by completing three aims. The first aim will determine the effects of TMZ dose and timing on host immunologic changes and the impact on PD-1 blockade efficacy for GBM. This aim will be tested by evaluating PD-1 and PD-L1 expression on host immune cells after various TMZ dosing strategies, and evaluating the effects of combining TMZ with PD-1 blockade on host immunologic function and tumor infiltrating lymphocytes in a syngeneic murine GBM model. The second aim will evaluate the utility of combining dose-modified TMZ and PD-1 blockade for resistant GBM tumors. This aim will utilize an MGMT-mediated TMZ resistant tumor model to determine the efficacy of combinatorial treatment for resistant phenotypes of GBM. The final aim will explore the mechanism by which dose-modified TMZ alters the tumor mico-environment and changes response to PD-1 blockade. The experiments will test the differences tumor genetic mutations and T cell clonality in tumors that respond to PD- 1 blockade compared to those that are resistant. Tumors that have been pre-treated with TMZ will also be tested to determine how post-treatment tumors may differ in response to immune checkpoint blockade independent of TMZ's effects on host immunity. At the completion of this proposal, the role of PD-1 blockade in combination with dose-modified TMZ for GBM and its efficacy for resistant phenotypes of GBM will be understood. These results have the potential for immediate impact for GBM patients as there are ongoing trials. The proposed research will be conducted by Dr. Rahman at the University of Florida Brain Tumor Immunotherapy Program (UFBTIP). She is well-suited to successfully complete the proposed research as an academic neurosurgeon with sub-specialty training in neuro-oncology. She has completed research fellowships under the direction of Dr. Brent Reynolds and Dr. Quinones-Hinojosa in studying tumor stem cells in malignant glioma and overcoming treatment resistance. She has completed an NIH funded program in clinical investigation and obtained her Master's degree from the Clinical and Translational Science Institute. Her primary mentor, Dr. Duane Mitchell, is the director of the UFBTIP, and has a strong record of extra-mural funding and success in investigating novel immunotherapeutic platforms for malignant brain tumors. Her co- mentors are Dr. Mark Gilbert and Dr. Amy Heimberger. Dr. Gilbert is chief of the Neuro-Oncology divison of the NCI. He has considerable clinical trial experience and lead an RTOG trial investigating dose-intensified TMZ for GBM and is currently leading a clinical trial exploring immune checkpoint blockade for GBM. Dr. Heimberger is a neurosurgeon-scientist at MD Anderson Cancer Center with expertise in immunotherapy for brain tumors and training young scientists. In addition to guiding her research, Dr. Heimberger will help Dr. Rahman learn to balance a clinical neurosurgical practice with translational research endeavors. Dr. Rahman has considerable funding and ample resources to accomplish her research goals through the UFBTIP. During the award period, Dr. Rahman will complete a comprehensive program to develop as a clinician scientist. This program will include completing the experimental protocols outlined in the proposal, completing course work in research methods and conduct, and regular scheduled meetings with her advisory panel which includes highly accomplished clinician scientists in neurosurgery, neuro-oncology and oncology. Her career goals include developing novel therapies for malignant glioma, understanding how to overcome tumor treatment resistance and improving outcomes for glioma patients. This career development program will be an important first step in achieving these goals.