Caspase-1 cleaves PPARγ for potentiating the pro-tumor action of TAMs

作者：Zhiyuan Niu, Qian Shi, Wenlong Zhang, Yuxin Shu, Nanfei Yang, Bing Chen, Qingsong Wang, Xuyang Zhao, Jiajia Chen, Nan Cheng, Xiujing Feng, Zichun Hua, Jianguo Ji, Pingping Shen · 发表于：Nature Communications · 年份：2017 · DOI：10.1038/s41467-017-00523-6 · 被引用次数：193 · 研究领域：Peroxisome Proliferator-Activated Receptors、Immune cells in cancer、Autophagy in Disease and Therapy

Tumor-associated macrophages are increasingly viewed as a target of great relevance in the tumor microenvironment, because of their important role in cancer progression and metastasis. However, the endogenous regulatory mechanisms underlying tumor-associated macrophage differentiation remain largely unknown. Here, we report that caspase-1 promotes tumor-associated macrophage differentiation by cleaving peroxisome proliferator-activated receptor gamma (PPARγ) at Asp64, thus generating a 41 kDa fragment. This truncated PPARγ translocates to mitochondria, where it directly interacts with medium-chain acyl-CoA dehydrogenase (MCAD). This binding event attenuates MCAD activity and inhibits fatty acid oxidation, thereby leading to the accumulation of lipid droplets and promoting tumor-associated macrophage differentiation. Furthermore, the administration of caspase-1 inhibitors or the infusion of bone marrow-derived macrophages genetically engineered to overexpress murine MCAD markedly suppresses tumor growth. Therefore, targeting the caspase-1/PPARγ/MCAD pathway might be a promising therapeutic approach to prevent tumor progression.Tumor associated macrophages (TAMs) promote cancer progression. Here, the author show that caspase-1 promotes TAMs differentiation by attenuating medium-chain acyl-CoA dehydrogenase activity and that inhibition of this axis results in suppression of tumour growth in a transgenic mouse model of breast cancer.