Engineering T Cell Adoptive Therapy for Glioblastoma

项目摘要 该提案集中在临床前胶质母细胞瘤（GBM）中T细胞受体（TCR）导向治疗的使用 模型GBM仍然是一种难以治疗的癌症，临床结果仍然很差。但尽管 尽管免疫疗法在癌症中的巨大影响，但仍然没有FDA批准的用于GBM的免疫疗法。 有几个原因导致难以将基于免疫的治疗扩展到中枢神经系统。 神经系统（CNS）。GBM携带很少的T细胞，被认为是"非炎症"， 树突状细胞在脑实质中，和无数的免疫抑制功能已被确定， 患者中枢神经系统也是免疫专业化的，由于存在位点特异性元素，没有看到 其他地方-例如，缺乏淋巴结，存在硬脑膜炎和血脑屏障， 他人此外，GBM的基因组景观引入了额外的障碍，因为许多抗原性和特异性结合都是不可避免的。 新抗原靶是不均匀分布的。重要的是，虽然异质性是一个可怕的 由于免疫疗法的挑战，它在临床前环境中的建模很差。尽管有这些障碍， CNS免疫治疗的最终目标-T细胞克隆扩增-保持不变。在这里，我们将测试使用 过继性转移的TCR定向T细胞治疗临床前GBM，作为理解关键的 最终临床转化的机械原理。我们组建了一个由Charest博士和Dr. Petti为这项工作带来了不同的专业知识。这项工作的重点是一种新型的转基因小鼠， 靶向GL261小鼠模型中的内源性新抗原突变体Imp3（mImp3）。这只老鼠 突变型Imp3特异性转基因（MISTIC）小鼠，表达识别H2-Db限制性T细胞的TCR。 mImp3新抗原因此代表了TCR导向细胞治疗的令人兴奋的模型。在目标1中，我们 剖析MISTIC治疗的机制，并了解内源性 在有效治疗中的RAG依赖性淋巴细胞群。此外，我们将开发和研究一种新的， 自发的、EGFR驱动的和新抗原定义的GBM模型的本地模型，使我们能够 研究MISTIC细胞疗法在生理环境中。在目标2中，我们将研究观察到的一小部分 小鼠逃避MISTIC治疗，并通过询问分子和细胞 通过表征肿瘤和微环境水平的变化来确定耐药性的基础。在目标3中， 我们将使用我们的同基因，CRISPR编辑的GL261克隆与野生型Imp3来模拟异质性，并探索 用细胞因子和趋化因子改造MISTIC细胞，以重塑GBM 微环境作为靶向异质性肿瘤的平台。我们将这种方法视为一种证明- 使用单抗原系统释放表位扩散的概念。这些目标将共同揭示新的 从TCR细胞治疗模型的见解，将导致新的本土模型的开发和探索 GBM异质性的工程方法，共同具有直接的翻译应用。

PROJECT SUMMARY This proposal centers on the use of T cell receptor (TCR) directed therapy in preclinical glioblastoma (GBM) models. GBM remains a difficult cancer to treat, and clinical outcomes remain poor. However, despite the seismic influence of immunotherapy in cancer, there remain no FDA approved immunotherapies for GBM. There are several reasons that underlie the difficulty in extending immune-based treatments to the central nervous system (CNS). GBM harbors few T cells and is considered “non-inflamed”, there is a paucity of dendritic cells in the brain parenchyma, and a myriad of immunosuppressive features has been identified in patients. The CNS is also immunologically specialized due to the presence of site-specific elements not seen elsewhere—e.g., lack of lymph nodes, presence of dural lymphatics, and the blood-brain barrier, among others. Moreover, the genomic landscape of GBM introduces additional obstacles in that many antigenic and neoantigenic targets are heterogeneously distributed. Importantly, although heterogeneity is a formidable challenge to immunotherapy, it is poorly modeled in preclinical settings. Despite these barriers, however, the final goal of CNS immunotherapy—T cell clonal expansion—remains the same. Here, we will test the use of adoptively transferred TCR directed T cells to treat preclinical GBM as a gateway to understand key mechanistic principles for ultimate clinical translation. We have assembled a team with Dr. Charest and Dr. Petti that brings diverse expertise to this work. The proposed work focuses on a novel transgenic mouse that targets an endogenous neoantigen, mutant Imp3 (mImp3), in the GL261 mouse model. This mouse, the Mutant Imp3 Specific TransgenIC (MISTIC) mouse, expresses a TCR that recognizes the H2-Db restricted mImp3 neoantigen and thus represents an exciting model for TCR-directed cell therapy. In Aim 1, we will dissect the mechanisms underlying MISTIC therapy and also understand the requirement for endogenous RAG-dependent lymphocyte populations in effective treatment. Additionally, we will develop and study a new, autochthonous model of spontaneous, EGFR-driven and neoantigenically-defined GBM model to allow us to study MISTIC cell therapy in physiologic settings. In Aim 2, we will study the observation that a small subset of mice escape MISTIC therapy and progress after prolonged survival by interrogating the molecular and cellular basis of resistance by characterizing changes at both the level of the tumor and microenvironment. In Aim 3, we will use our isogenic, CRISPR-edited GL261 clones with wild type Imp3 to model heterogeneity and explore the engineering of MISTIC cells with cytokines and chemokines designed to remodel the GBM microenvironment as a platform to target heterogeneous tumors. We envision this approach as a proof-of - concept to use single-antigen systems to unleash epitope spreading. Together, these Aims will reveal new insights from a TCR cell therapy model that will lead to novel autochthonous model development and explore engineering approaches for GBM heterogeneity that, together, have immediate translational applications.