Anti-tumor efficacy of novel cGAS-STING pathway agonists

项目总结 这项提议的目标是对激活先天的新化合物进行分子和免疫学检查。 蛋白质环GMP-AMP(CGAMP)合成酶(CGAS)及其刺激因子介导的免疫信号 干扰素基因(刺痛)。先天免疫是在模式识别受体通过以下途径启动的 指示微生物感染或死亡细胞的分子。这些都导致了适应性免疫的协调 随后消除癌症或感染组织的反应。CGAMP是GAMP的主要激活配体 STING及其合成是由cGAS与胞浆DNA接触而触发的。巨噬细胞、树突状细胞 (DC)，内皮细胞在吞噬来自凋亡细胞的物质后暴露在胞浆DNA中 包括那些在肿瘤微环境中的。STIN介导的信号转导导致I型干扰素的分泌 (干扰素-I)和促炎细胞因子，然后激活抗原提呈细胞(APC)，从而促进 抗原导向的T细胞杀伤。事实上，刺痛是启动免疫反应所必需的，能够清除 肿瘤细胞。有趣的是，药物对刺痛依赖过程的激活可以导致自发的 在小鼠模型中肿瘤清除甚至肿瘤抗原衍生的保护性免疫。许多努力都是 从而着重于了解刺痛介导的治疗的分子和免疫学基础 结果以及确定可以安全地引发这些结果的新的分子实体。我们的工作已经确定了六个 诱导cGAS介导的cGAMP合成的小分子类似物，而不影响细胞内DNA水平。 它们直接激活人类和小鼠细胞中依赖于刺的表型。此外，肿瘤内 在小鼠肿瘤模型中给予原始母体分子会导致肿瘤生长和 延长动物的存活时间。我们假设，当我们改进的类似物与优化的配方配对时 用于体内使用，将显示增强的抗肿瘤活性。据我们所知，这些是第一个合成的直接 CGAS介导的信号转导的诱导物尚未描述。因此，他们在建立cGAS方面处于独特的地位 (也许是一般的刺痛调节蛋白)作为一个可行的药物靶点，也揭示了对 CGAS-STING在抗肿瘤免疫中的作用因此，我们建议进行一项深入和比较的 免疫学和分子反应、抗肿瘤能力和潜在不良反应的特征 我们的新型cGAS激动剂制剂在小鼠癌症模型中的作用。结果将允许机械式的 对它们的免疫治疗效用进行评估，特别是与临床应用的比较 分子和涉及与检查点抑制剂结合的治疗中。我们历史悠久的协作团队 在先天免疫、分子生物学、T细胞免疫学和癌症免疫治疗方面拥有专业知识， 因此能够很好地执行这些研究。

PROJECT SUMMARY The goal of this proposal is a molecular and immunological examination of novel compounds that activate innate immune signaling mediated by the proteins cyclic GMP-AMP (cGAMP) synthase (cGAS) and Stimulator of Interferon Genes (STING). Innate immunity is initiated following engagement of pattern recognition receptors by molecules indicative of microbial infection or dying cells. These lead to the orchestration of adaptive immune responses that subsequently eliminate cancerous or infected tissues. cGAMP is the primary activating ligand of STING and its synthesis is triggered by contact between cGAS and cytosolic DNA. Macrophages, dendritic cells (DCs), and endothelial cells are exposed to cytosolic DNA following phagocytosis of material from apoptotic cells including those in the tumor microenvironment. STING-mediated signaling leads to secretion of type I interferons (IFN-I) and proinflammatory cytokines that then activate antigen-presenting cells (APCs), thereby facilitating antigen-directed T-cell killing. STING is, in fact, required for initiating immune responses capable of clearing tumor cells. Intriguingly, pharmacologic activation of STING-dependent processes can lead to spontaneous tumor clearance and even tumor antigen-derived protective immunity in murine models. Numerous efforts are thus focused on understanding the molecular and immunological bases of STING-mediated therapeutic outcomes as well as identifying new molecular entities that can safely elicit these. Our work has identified six small molecular analogs that induce cGAS-mediated synthesis of cGAMP without affecting cytosolic DNA levels. These directly activate STING-dependent phenotypes in both human and murine cells. Moreover, intratumoral administration of the original parent molecule in mouse models of cancer led to impaired tumor growth and prolonged animal survival. We hypothesize that our improved analogs, when paired with formulations optimized for in vivo use, will exhibit enhanced antitumor activity. To our knowledge these represent the first synthetic direct inducers of cGAS-mediated signaling yet described. As such, they are uniquely positioned to establish cGAS (and perhaps STING regulatory proteins in general) as a viable drug target and also reveal new insights into the role of cGAS-STING in antitumor immunity. We thus propose to undertake a penetrative and comparative characterization of the immunological and molecular responses, anti-tumor capacities, and potential adverse effects of our novel cGAS agonist formulations in murine models of cancer. Results will allow a mechanistic assessment to be made of their immunotherapeutic utility, especially in comparison to clinically pursued molecules and in therapies involving combination with checkpoint inhibitors. Our historically collaborative group possesses expertise in innate immunity, molecular biology, T cell immunology, and cancer immunotherapy and is thus well positioned to execute these studies.