Coagulation factors as modifiers of the colon cancer microenvironment

 描述（由申请人提供）：本研究项目的目的是确定止血因子促进结直肠癌（CRC）发病的机制。越来越多的证据表明，CRC病理生物学是唯一依赖于中央止血蛋白酶，凝血酶。凝血酶在CRC发病机制中的独特重要性被PI实验室最近发表的研究所证实，这些研究表明凝血酶和纤维蛋白原驱动结肠炎相关结肠癌的肿瘤发生。这些研究代表了凝血酶/纤维蛋白原轴在肿瘤发生和肿瘤生长中起主要作用的唯一明确的例子。拟议的研究建立在这些结果以及强有力的初步数据的基础上，这些数据揭示了癌前和恶性肿瘤微环境中凝血酶介导的蛋白水解是CRC发病机制的广泛重要决定因素，而不仅仅是与炎症性结肠炎相关的环境。凝血酶似乎通过与纤维蛋白原和凝血酶激活受体蛋白酶激活受体-1（PAR-1）偶联的独特机制促进CRC肿瘤发生和肿瘤生长。拟议的研究将直接定义凝血酶与CRC发病机制的耦合机制，并首次探索最近批准的和下一代靶向凝血酶原的药理学药物的治疗潜力，以阻止CRC的发展和进展。本提案中的研究将使用专门为此提案开发的新型基因靶向小鼠系、尖端药理学药物和创新的补充体外分析来测试以下特定假设：1）凝血酶/纤维蛋白原轴在将局部免疫微环境向能够支持肠肿瘤发生的致病性、炎性状态转变方面广泛重要，2）血管外纤维蛋白沉积，特别是纤维蛋白介导的整合素β M β 2的结合，驱动肠肿瘤发生B，将肠单核细胞推向促肿瘤发生表型，3）纤维蛋白介导的巨噬细胞相关β M β 2的结合触发促肿瘤发生细胞因子、趋化因子和生长因子的NF-κ B依赖性产生，从而支持转化的肠上皮细胞的增殖/存活，4）凝血酶还通过激活不同的组织特异性PAR-1信号传导机制与CRC的发生和进展偶联，所述组织特异性PAR-1信号传导机制涉及癌前和肿瘤微环境中的巨噬细胞以及转化的肠上皮细胞，和5）CRC发病机制可以通过多种不同的药理学方法在凝血酶原表达或凝血酶产生水平上限制小鼠。拟议的研究将为止血因子在CRC病理生物学中的精确贡献提供急需的见解，将阐明凝血酶介导的蛋白水解与CRC进展偶联的关键机制途径，并将在实验动物中提供关于高级抗凝剂作为辅助治疗预防或治疗CRC的可翻译性的基本原理验证数据。

 DESCRIPTION (provided by applicant): The objective of this research program is to define the mechanisms by which hemostatic factors promote colorectal cancer (CRC) pathogenesis. Growing evidence suggests that CRC pathobiology is uniquely dependent on the central hemostatic protease, thrombin. The unique importance of thrombin in CRC pathogenesis is evinced by recently published studies from the PIs laboratory revealing that thrombin and fibrinogen drive tumorigenesis in colitis-associated colon cancer. These studies represent the only definitive example of a context where the thrombin/fibrinogen axis plays a major role in tumorigenesis and tumor growth. The proposed studies build on these results, as well as powerful preliminary data revealing that thrombin-mediated proteolysis in the premalignant and malignant tumor microenvironments is a broadly important determinant of CRC pathogenesis, not just settings associated with inflammatory colitis. Thrombin appears to promote CRC tumorigenesis and tumor growth through unique mechanisms coupled to fibrinogen and the thrombin-activatable receptor, protease activated receptor-1 (PAR-1). The proposed studies will directly define the mechanisms coupling thrombin to CRC pathogenesis, and explore, for the first time, the therapeutic potential of recently approved and next-generation pharmacological agents targeting pro/thrombin to impede the development and progression of CRC. The studies in this proposal will use novel gene-targeted mouse lines developed specifically for this proposal, cutting-edge pharmacological agents, and innovative complementary in vitro analyses to test the following specific hypotheses: 1) the thrombin/fibrinogen axis is broadly important in shifting the local immunological microenvironment towards a pathogenic, inflammatory state capable of supporting intestinal tumorigenesis, 2) extravascular fibrin deposition, and specifically fibrin-mediated engagement of the integrin M2, drives intestinal tumorigenesis b pushing intestinal monocytes toward a pro-tumorigenic phenotype, 3) fibrin-mediated binding of macrophage-associated M2 triggers NF-κB-dependent production of pro-tumorigenic cytokines, chemokines, and growth factors, thereby supporting the proliferation/survival of transformed intestinal epithelial cells, 4) thrombin is also coupled to the development and progression of CRC through activation of distinct, tissue-specific PAR-1 signaling mechanisms involving macrophages in the premalignant and tumor microenvironments, as well as transformed intestinal epithelial cells, and 5) CRC pathogenesis can be limited in mice by multiple distinct pharmacological approaches at the level of prothrombin expression or thrombin generation. The proposed studies will provide much needed insights into the precise contribution of hemostatic factors in CRC pathobiology, will illuminate key mechanistic pathways coupling thrombin-mediated proteolysis to CRC progression, and will provide essential proof-of-principle data in experimental animals regarding the translatability of advanced anticoagulants as adjuvant therapy for the prevention or treatment of CRC.