Targeting GRP94-TGF-beta Pathway for Cancer Immunotherapy

项目摘要 GRP 94作为内质网中普遍存在的HSP 90蛋白，对蛋白质的质量起着重要作用 通过参与未折叠蛋白质反应和ER相关蛋白质反应来控制分泌途径。 蛋白质降解途径我的实验室已经证明GRP 94是一个具有战略意义的目标， 癌症，因为它控制着细胞生长，迁移，免疫耐受和 在一个实施方案中，所述细胞分化抑制剂包括整合素、TLR、IGF-II、Wnt共受体LRP 6和GARP（或LRRC 32）。GARP （糖蛋白A重复占主导地位）负责表面对接和激活潜伏的TGF β和TGF β受体。 我们已经通过免疫学和生物医学领域的研究， 生物化学研究，包括：1）GARP是通过调节癌症免疫逃避的重要分子， 多种细胞类型（例如，癌细胞、血小板、调节性T细胞、B细胞）。2)我们发现了一种新的机制 通过GARP的蛋白水解切割从细胞表面GARP-TGF β复合物活化TGF β。3)GARP一直在 发现在多种人类癌症中异常表达，通过癌细胞内源性 和-外部机制。4)临床前研究表明，GARP是一种新型的肿瘤治疗靶点 免疫疗法这些成果加深了我们的信念，GRP 94及其客户的研究 网络将导致更好地了解这种伴侣生物学在癌症和发展新的癌症 治疗剂，单独或与批准的免疫抑制剂组合。在研究的下一阶段， 我们将提出一个假设，即GRP 94/GARP靶向治疗应用于多种易受攻击的癌症， 克服对检查点抑制剂的免疫抵抗。 首先，我们将确定GRP 94调节TGF β生物合成的作用和分子机制， 激活和信号传导。该目标将集中于GRP 94-GARP复合物的结构分析，并解决 GRP 94折叠在调节TGF β信号传导中重要的另外两种分子：LRRC 33和 LRG 1。其次，我们将开发针对GRP 94和GARP的新型癌症免疫策略。的 目标是通过里程碑驱动的 战略这包括抑制GARP切割的试剂、GARP特异性抗体、药物样GRP 94选择性抗体、GARP特异性抗体和GARP特异性抗体。 抑制剂，针对优先在癌细胞上表达的细胞表面GRP 94（ectoGRP 94）的抗体，和 T细胞被工程化以表达嵌合抗原受体（CAR），所述嵌合抗原受体由针对人T细胞的单链抗体组成。 与T细胞信号传导基序融合的ectoGRP 94（GRP 94-CAR-T）。总的来说，这项研究的影响在于 基本了解GRP 94在调节TGF β通路和开发有前途的下一个 产生免疫抑制剂。

PROJECT SUMMARY As a ubiquitous HSP90 paralog in the endoplasmic reticulum (ER), GRP94 plays important roles in protein quality control in the secretory pathway by participating in both the unfolded protein response and the ER-associated protein degradation pathway. My laboratory has demonstrated that GRP94 is a strategically important target for cancer, because it controls multiple key molecular pathways in cell growth, migration, immune tolerance and differentiation, including integrins, TLRs, IGF-II, Wnt co-receptor LRP6, and GARP (or LRRC32). GARP (Glycoprotein A Repetitions Predominant) is responsible for surface docking and activation of latent TGFb and a focus of this proposal We have made significant contributions to this area through immunological and biochemical studies, including: 1) that GARP is an important molecule for cancer immune evasion via regulating multiple cell types (e.g., cancer cells, platelets, regulatory T cells, B cells). 2) We discovered a novel mechanism of TGFb activation from cell surface GARP-TGFb complex via proteolytic cleavage of GARP. 3) GARP has been found to be aberrantly expressed in multiple human cancers to promote oncogenesis via both cancer cell-intrinsic and -extrinsic mechanisms. 4) Preclinical studies suggest that GARP is a novel therapeutic target for cancer immunotherapy. These accomplishments have deepened our conviction that the study of GRP94 and its client network will lead to better understanding of this chaperone biology in cancer and to development of novel cancer therapeutics, alone or in combination with approved immunotherapeutic agents. In the next phase of the study, we will address the hypothesis that GRP94/GARP-targeted therapy applied to multiple vulnerable cancers will overcome immune resistance to checkpoint inhibitors. First, we will determine the roles and molecular mechanism involved in GRP94 regulation of TGFb biogenesis, activation and signaling. This aim will focus on structural analysis of the GRP94-GARP complex, and on resolving mechanisms of GRP94 in folding two other molecules important in regulating TGFb signaling: LRRC33 and LRG1. Second, we will develop novel cancer immunotherapeutic strategies targeting GRP94 and GARP. The goal is to advance the top first-in-class agent(s) among several pre-clinical leads through a milestone-driven strategy. This includes agents to inhibit GARP cleavage, GARP-specific antibodies, drug-like GRP94-selective inhibitors, antibodies against the cell surface GRP94 (ectoGRP94) preferentially expressed on cancer cells, and T cells engineered to express chimeric antigen receptor (CAR) composed of a single-chain antibody against ectoGRP94 fused with T cell signaling motifs (GRP94-CAR-T). Overall, the impact of this study lies in fundamental understanding of GRP94 in regulating the TGFb pathway and in developing promising next generation immunotherapeutic agents.