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

项目总结 摘要胶质母细胞瘤是成人最常见的原发脑肿瘤，具有侵袭性的特点。 生长，严重的神经系统疾病，并最终死亡。替莫唑胺(TMZ)是应用最广泛的 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 病人。因此，人们正在研究新的治疗方法，如免疫检查点抑制剂。 对于GBM。免疫检查点是由肿瘤细胞选择的免疫抑制反应。 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 针对肿瘤新抗原的激活。这种方法在治疗固体肿瘤方面取得了巨大的成功。 组织肿瘤，目前正在测试对GBM的疗效。 这项研究计划将研究剂量修饰的TMZ可能激活宿主T细胞的机制 和肿瘤新抗原的表达，以提高对PD-1免疫检查点阻断的反应。其基本原理是 这项提议包括几个因素。首先，已经发现TMZ在组合使用时是有利的 TMZ诱导的恢复期宿主免疫调节对GBM的免疫治疗 淋巴细胞减少症。第二，免疫检查点抑制剂增强抗肿瘤T细胞对肿瘤的反应 新抗原。这种现象可以利用，因为TMZ已知是诱变的，并导致 恶性胶质瘤中肿瘤新抗原负荷增加。第三，TMZ和PD-1联合封锁具有 由于这些肿瘤的PD-L1表达增加，因此对耐药表型的GBM具有独特的作用。 这项提议将检验TMZ诱导宿主免疫学和肿瘤基因变化的假设，这将 导致对PD-1阻断的反应增强。这一假设将通过完成三个目标来检验。这个 第一个目标将确定TMZ的剂量和时机对宿主免疫变化的影响以及对 PD-1对基底膜的阻断作用。这一目标将通过评估主机上PD-1和PD-L1的表达来测试 TMZ不同给药策略对免疫细胞的影响及TMZ与PD-1联合应用的效果 阻断同基因小鼠GBM模型的宿主免疫功能和肿瘤浸润性淋巴细胞。 第二个目标将评估剂量调整的TMZ和PD-1阻断联合治疗耐药的GBM的有效性 肿瘤。这一目标将利用MGMT介导的TMZ耐药肿瘤模型来确定 GBM耐药表型的联合治疗。最终目标将探索通过什么机制 剂量修饰的TMZ改变了肿瘤微环境，改变了对PD-1阻断的反应。这个 实验将测试对PD-1有反应的肿瘤的肿瘤基因突变和T细胞克隆的差异。 与那些抵抗的人相比，1个封锁。已经用TMZ预治疗的肿瘤也将被 测试以确定治疗后肿瘤对免疫检查点阻断的反应有何不同 与TMZ对宿主免疫的影响无关。在这项提议完成时，PD-1封锁在 联合剂量修饰的TMZ治疗GBM及其对GBM耐药表型的疗效 明白了。这些结果有可能对GBM患者产生直接影响，因为有正在进行的 审判。 这项拟议的研究将由佛罗里达大学脑瘤大学的拉赫曼博士进行 免疫治疗计划(UFBTIP)。她非常适合成功地完成拟议的研究 在神经肿瘤学方面有专科训练的学术神经外科医生。她已经完成了研究 在Brent Reynolds博士和Quinones-Hinojosa博士的指导下研究肿瘤干细胞 在恶性胶质瘤中，克服治疗耐药性。她已经完成了美国国立卫生研究院资助的一个项目 她从事临床研究，并在临床和翻译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，在壁外方面有很好的记录 为研究恶性脑瘤的新型免疫治疗平台提供资金并取得成功。她的搭档- 导师是马克·吉尔伯特博士和艾米·海姆伯格博士。吉尔伯特博士是世界卫生组织神经肿瘤科主任 美国国家情报局。他有丰富的临床试验经验，并领导了一项研究剂量增强型TMZ的RTOG试验 目前正在领导一项临床试验，探索对GBM的免疫检查点阻断。Dr。 Heimberger是MD Anderson癌症中心的神经外科医生兼科学家，在免疫治疗方面拥有专业知识 脑瘤和培训年轻科学家。除了指导她的研究，海姆伯格博士还将帮助Dr。 拉赫曼学会了平衡临床神经外科实践和翻译研究努力。拉赫曼博士 拥有可观的资金和充足的资源，通过UFBTIP实现她的研究目标。在.期间 在获奖期间，拉赫曼博士将完成一个全面的项目，以发展成为一名临床医生科学家。这 课程将包括完成提案中概述的实验方案，完成课程作业 研究方法和行为，以及与她的顾问小组定期安排的会议，其中包括 在神经外科、神经肿瘤学和肿瘤学方面有丰富经验的临床科学家。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阻力 并改善胶质瘤患者的预后。这一职业发展计划将是 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.