Fgl-2 targeted therapy for reversing multi-modality immune suppression

我们这个应用程序的目标是测试这样一个假设：阻断新发现的免疫抑制 基底膜调节因子纤维蛋白原样蛋白2将全面逆转肿瘤介导的免疫 抑制，从而允许中枢神经系统内的胶质瘤的免疫清除。我们有 发现Fgl2在GBM组织中高度表达(最近由JNCI发表)。患有基底膜的患者 具有高水平Fgl2表达的肿瘤总体生存时间在统计学上比那些 表达水平较低。作为概念的进一步证明，Fgl2工程的GBM肿瘤进展迅速 神经后遗症和死亡与报告基因-GFP工程的同基因GBM细胞的比较 老鼠。我们的数据显示，Fgl2是一个关键的免疫抑制枢纽，与免疫检查点相关 家族表达(PD-L1、PD-1和CTLA-4)、免疫抑制细胞因子(转化生长因子-β)和胶质瘤浸润性， 免疫抑制免疫群体，如髓系来源的抑制细胞(MDSCs)、Tregs和M2 巨噬细胞。这种观察的一个潜在机制是Fgl2诱导T细胞中的CD39和CD73。这个 CD39蛋白将ATP转化为ADP和AMP，再由CD73转化为腺苷。腺苷是一种 免疫抑制代谢物，然后抑制T淋巴细胞激活和效应器功能。 此外，CD39/CD73复合体促进M1转化为促肿瘤M2，从而促进 肿瘤生长。基于这些数据，我们创造了一种阻断Fgl2免疫的第一代抗体 在已建立的脑内胶质瘤小鼠模型中，抑制活性和提高中位生存期。 为了测试我们对这一应用程序的中心假设，提出了以下目标：目标1：确定 人肾小球基底膜Fgl2表达与免疫抑制的关系及其机制探讨 CD39/CD73在不同类型免疫细胞中的表达；目的2：选择治疗效果最好的 有效的跨物种Fgl2单抗，促进抗肿瘤免疫反应。 影响：这项研究将产生一种治疗候选--一种可能逆转肿瘤的Fgl2封闭抗体-- 介导性免疫抑制与基底膜免疫抑制细胞数量。考虑到Fgl2 可以在几乎所有的GBM中检测到，大多数都有非常高的水平，这样的候选治疗方法将是 很重要。这项研究还将进一步从机制上阐明Fgl2是如何调节免疫抑制基因的 在免疫抑制细胞和效应器免疫群体中表达。最后，这项研究将表明 用我们新发明的通用CTC检测循环GBM肿瘤细胞(CTC)中的Fgl2 捕获技术(PCT/US 2014/020615)将与基底膜肿瘤Fgl2表达水平相关，作为 用于指导未来封闭治疗的生物标志物。这种类型的检测也将具有非常重要的意义 可用于多个临床背景的基因表达分析的纵向液体活检 应用如早期进展/治疗失败和对治疗的反应。

Our goal of this application is to test the hypothesis that blocking the newly identified immune suppressive regulator fibrinogen-like protein 2 (Fgl2) in GBM will comprehensively reverse tumor-mediated immune suppression thereby allowing immunological clearance of gliomas within the central nervous system. We have discovered that Fgl2 is highly expressed in GBM tissues(recently published by JNCI). Patients with GBM tumors that have high levels of Fgl2 expression have a statistically shorter overall survival time relative to those with low expression levels. As further proof of concept, Fgl2-engineered GBM tumors progressed rapidly with neurological sequela and death when compared to the reporter gene-GFP-engineered GBM cells in syngeneic mice. Our data shows that Fgl2 is a key immune suppressive hub that correlates with immune checkpoint family expression (PD-L1, PD-1, and CTLA-4), immune suppressive cytokines (TGF-β), and glioma-infiltrating, of immunosuppressive immune populations such as myeloid-derived suppressor cells (MDSCs), Tregs and M2 macrophages. One underlying mechanism for this observation is Fgl2 induced CD39 and CD73 in T cells. The CD39 protein converts ATP to ADP and AMP, which is then converted to adenosine by CD73. Adenosine is an immunosuppressive metabolite that then suppresses T lymphocyte activation and effector function. Furthermore, the CD39/CD73 complex enhances the conversion of M1 into tumor-promoting M2 to promote tumor growth. Based on these data, we have created a first generation antibody that blocks Fgl2 immune suppressive activity and increases median survival in murine models with established intracerebral gliomas. To test our central hypothesis for this application, the following aims are proposed: Aim 1: Determine the association of Fgl2 expression with immune suppression in human GBM and investigate the mechanism of CD39/CD73 expression in different types of immune cells in GBM; Aim 2: Select the most therapeutically efficacious cross-species Fgl2 mAb that promotes antitumor immune response. Impact: This study will yield a therapeutic candidate – a Fgl2 blocking antibody that may reverse tumor- mediated immune suppression and the number of immune suppressive cells in GBM. Considering that Fgl2 can be detected in almost all GBMs, with most having very high levels, such a candidate therapeutic will be important. This study will also further mechanistically elucidate how Fgl2 regulates immune suppressive gene expression in immune suppressive cells and within effector immune populations. Finally, this study will show whether detection of Fgl2 in circulating GBM tumor cells (CTC) using our newly invented universal CTC capture technology (PCT/US2014/020615) will correlate with the level of GBM tumor Fgl2 expression as a biomarker for guiding blocking therapy in the future. This type of assay would also be highly significant as a longitudinal liquid biopsy for gene expression analysis that could be used in the context of multiple clinical applications such as early progression/treatment failure and response to treatment.