Suarez-Lopez Lucia, Kong Yi Wen, Sriram Ganapathy, Patterson Jesse C, Rosenberg Samantha, Morandell Sandra, Haigis Kevin M, Yaffe Michael B
Center for Precision Cancer Medicine, Koch Institute for Integrated Cancer Research and Departments of Biological Engineering and Biology, Massachusetts Institute of Technology, Cambridge, MA, United States.
Department of Cancer Biology, Dana Farber Cancer Institute, Boston, MA, United States.
Front Immunol. 2021 Feb 23;11:607891. doi: 10.3389/fimmu.2020.607891. eCollection 2020.
Chronic inflammation increases the risk for colorectal cancer through a variety of mechanisms involving the tumor microenvironment. MAPK-activated protein kinase 2 (MK2), a major effector of the p38 MAPK stress and DNA damage response signaling pathway, and a critical regulator of pro-inflammatory cytokine production, has been identified as a key contributor to colon tumorigenesis under conditions of chronic inflammation. We have previously described how genetic inactivation of MK2 in an inflammatory model of colon cancer results in delayed tumor progression, decreased tumor angiogenesis, and impaired macrophage differentiation into a pro-tumorigenic M2-like state. The molecular mechanism responsible for the impaired angiogenesis and tumor progression, however, has remained contentious and poorly defined. Here, using RNA expression analysis, assays of angiogenesis factors, genetic models, macrophage depletion and reconstitution of macrophage MK2 function using adoptive cell transfer, we demonstrate that MK2 activity in macrophages is necessary and sufficient for tumor angiogenesis during inflammation-induced cancer progression. We identify a critical and previously unappreciated role for MK2-dependent regulation of the well-known pro-angiogenesis factor CXCL-12/SDF-1 secreted by tumor associated-macrophages, in addition to MK2-dependent regulation of Serpin-E1/PAI-1 by several cell types within the tumor microenvironment.
慢性炎症通过涉及肿瘤微环境的多种机制增加结直肠癌风险。丝裂原活化蛋白激酶激活的蛋白激酶2(MK2)是p38丝裂原活化蛋白激酶应激和DNA损伤反应信号通路的主要效应器,也是促炎细胞因子产生的关键调节因子,已被确定为慢性炎症条件下结肠肿瘤发生的关键促成因素。我们之前描述了在结肠癌炎症模型中MK2的基因失活如何导致肿瘤进展延迟、肿瘤血管生成减少以及巨噬细胞向促肿瘤的M2样状态分化受损。然而,导致血管生成受损和肿瘤进展的分子机制仍存在争议且定义不清。在这里,我们使用RNA表达分析、血管生成因子检测、遗传模型、巨噬细胞耗竭以及通过过继性细胞转移重建巨噬细胞MK2功能,证明巨噬细胞中的MK2活性对于炎症诱导的癌症进展过程中的肿瘤血管生成是必要且充分的。我们发现,除了肿瘤微环境中几种细胞类型对丝氨酸蛋白酶抑制剂E1/纤溶酶原激活物抑制剂-1(Serpin-E1/PAI-1)的MK2依赖性调节外,肿瘤相关巨噬细胞分泌的著名促血管生成因子CXCL-12/基质细胞衍生因子-1(CXCL-12/SDF-1)的MK2依赖性调节也起着关键且此前未被认识到的作用。