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

我们的目标是测试阻断新发现的免疫抑制因子的假设， GBM中的调节纤维蛋白原样蛋白2（Fgl 2）将全面逆转肿瘤介导的免疫反应， 抑制，从而允许中枢神经系统内的神经胶质瘤的免疫清除。我们有 发现Fgl 2在GBM组织中高度表达（最近由JNCI发表）。GBM患者 具有高水平Fgl 2表达的肿瘤相对于具有高水平Fgl 2表达的肿瘤具有统计学上更短的总体存活时间。 低表达水平。作为概念的进一步证明，Fgl 2工程化的GBM肿瘤随着Fgl 2基因的表达而快速进展。 神经后遗症和死亡的报告基因-GFP工程GBM细胞相比，在同基因 小鼠我们的数据显示Fgl 2是与免疫检查点相关的关键免疫抑制中心， 家族表达（PD-L1、PD-1和CTLA-4）、免疫抑制细胞因子（TGF-β）和神经胶质瘤浸润， 免疫抑制性免疫群体，如骨髓来源的抑制细胞（MDSC）、TCFs和M2 巨噬细胞该观察结果的一个潜在机制是Fgl 2诱导T细胞中的⑶ 39和⑶ 73。的 CD 39蛋白将ATP转化为ADP和AMP，然后由CD 73转化为腺苷。腺苷是一种 免疫抑制代谢物，然后抑制T淋巴细胞活化和效应子功能。 此外，CD 39/CD 73复合物增强了M1转化为促肿瘤M2，从而促进肿瘤的发生。 肿瘤生长基于这些数据，我们已经创建了阻断Fgl 2免疫的第一代抗体， 抑制活性，并增加具有已建立的脑内胶质瘤的鼠模型的中位生存期。 为了测试我们针对该应用的中心假设，提出了以下目标： Fgl 2表达与人GBM中免疫抑制的相关性，并研究其机制。 GBM中不同类型免疫细胞中的CD 39/CD 73表达;目的2：选择治疗效果最好的 有效的跨物种Fgl 2 mAb，其促进抗肿瘤免疫应答。 影响：这项研究将产生一种治疗候选物-一种可以逆转肿瘤的Fgl 2阻断抗体- 介导的免疫抑制和GBM中免疫抑制细胞的数量。考虑到Fgl 2 可以在几乎所有的GBM中检测到，其中大多数具有非常高的水平， 重要.本研究也将进一步阐明Fgl 2调控免疫抑制基因的机制 在免疫抑制细胞和效应免疫群体内表达。最后，这项研究将表明， 是否使用我们新发明的通用CTC检测循环GBM肿瘤细胞（CTC）中的Fgl 2 捕获技术（PCT/US 2014/020615）将与GBM肿瘤Fgl 2表达水平相关， 生物标志物，用于指导未来的阻断治疗。这种类型的分析也将是非常重要的， 用于基因表达分析的纵向液体活检，可用于多种临床 例如早期进展/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.