Autochthonous and Ex-vivo Derived Mouse Models of Malignant Glioma

项目摘要/摘要 尽管投入了大量资源来开发更好的治疗方法，但多形性胶质母细胞瘤(GBM) 患者面临的治疗选择很少，而且普遍结果很差。通过治疗，中位数 存活期为15个月。免疫疗法可能拥有最大的潜力来对抗这种可怕的疾病 疾病，但关于免疫系统和大脑之间的关系仍然存在许多问题， 尤其是免疫系统和脑癌。免疫反应的哪些组成部分是 对胶质母细胞瘤的免疫反应是不可缺少的？为什么免疫系统最终无法控制 GBM？此外，我们如何利用免疫反应来更好地治疗胶质母细胞瘤？这个项目的重点是 询问胶质母细胞瘤的这些方面，并有效地做到这一点，首先要从更好的小鼠模型开始，这是 这个项目的中心推力。 免疫编辑假说假定癌细胞提供源自自身的多肽。 突变的蛋白质，可以被免疫系统识别为外来的蛋白质。这些突变的作用是 靶点，可以标记肿瘤以供细胞毒性T细胞破坏。在这个过程中， 肿瘤进化为免疫原性降低，并与免疫系统保持平衡。最终， 肿瘤会产生较少的免疫原性靶点，并有效地使免疫系统看不见。对此 一旦肿瘤脱离免疫系统的控制，就会出现临床症状。这一过程是如何发生的 对中枢神经系统的影响知之甚少。人类的GBM构成了额外的挑战，因为它们 突变负担低，因此几乎没有突变可供靶向。目前的GBM小鼠模型要么有 高突变负荷，或低突变负荷，但由于各种原因不适合研究肿瘤免疫 系统交互。这个项目的模型将使用慢病毒作为传递两种致癌蛋白的手段 和Cre重组酶以精确的方式切除loxP侧翼的肿瘤抑制基因，在免疫成熟的情况下 纯基因背景的老鼠。这种原生的、原位的临床前模式将更忠实地 重述一下这种疾病在人类身上发生的情况。该系统还将用于开发一种超突变的 建立突变负荷与关卡封锁关系的复发性GBM模型 中枢神经系统肿瘤的敏感性。这些模型将更好地模拟在人类中看到的疾病，因为 他们的低突变负担，因为基因定位是精确的，因为免疫系统将如何“看到” 这种肿瘤类似于人类的疾病，而且由于肿瘤形成的固有性质。 这些基底膜的基因工程小鼠模型将回答有关如何 免疫系统与GBM相互作用，将建立突变负担和检查点之间的关系 阻断中枢神经系统肿瘤的敏感性，并有望导致更有效的治疗方法的开发。

PROJECT SUMMARY/ABSTRACT Despite immense resources devoted to developing better treatments, glioblastoma multiforme (GBM) patients face a paucity of treatment options and universally have poor outcomes. With treatment, the median survival is fifteen months. Immunotherapy treatment likely holds the greatest potential to combat this terrible disease, and yet many questions remain regarding the relationship between the immune system and the brain, and in particular, the immune system and cancer of the brain. Which components of immune response are indispensable for the immune response to glioblastoma? Why does the immune system ultimately fail to control GBM? Further, how can we leverage the immune response to better treat glioblastoma? This project focuses on interrogating these aspects of glioblastoma, and to effectively do so begins with better mouse models, which is the central thrust of this project. The immune editing hypothesis postulates that cancer cells present peptides derived from their own mutated proteins, which can be recognized as foreign by the immune system. These mutations function as targets, which can mark the tumor for destruction by cytotoxic T cells. During the course of this process, the tumor evolves to become less immunogenic and persists in equilibrium with the immune system. Eventually, the tumor gives rise to less immunogenic targets and effectively becomes invisible to the immune system. At this point, the tumor escapes beyond the immune system’s control and presents clinically. How this process occurs in the central nervous system is less well understood. Human GBMs pose the additional challenge in that they carry low mutational burden, and hence have few mutations to target. Current mouse models of GBM either have high mutational burden, or low mutational burden but are for various reasons unsuitable to study tumor-immune system interactions. The model for this project will use lentivirus as a means to deliver both oncogenic proteins and Cre-recombinase to excise loxP flanked tumor-suppressors in a precise way, in immunologically mature mice, of a pure genetic background. This autochthonous, orthotopic pre-clinical model will more faithfully recapitulate the disease as it occurs in humans. This system will also be employed to develop a hypermutated model of recurrent GBM to establish the relationship between mutational burden and checkpoint blockade sensitivity in CNS tumors. These models will be superior for simulating the disease seen in humans because of their low mutational burden, because the genetic targeting is precise, because how the immune system will “see” the tumor is similar to the human disease, and because of the autochthonous nature of tumor formation. These genetically engineered mouse models of GBM will answer fundamental questions regarding how the immune system interacts with GBM, will establish the relationship between mutational burden and checkpoint blockade sensitivity of CNS tumors, and will hopefully lead to development of more effective treatments.