Yao Yongfang, Shi Qian, Chen Bing, Wang Qingsong, Li Xinda, Li Long, Huang Yahong, Ji Jianguo, Shen Pingping
From the State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing 210023, China.
the Division of Nephrology, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229.
J Biol Chem. 2016 Aug 12;291(33):17450-66. doi: 10.1074/jbc.M116.717868. Epub 2016 Jun 20.
Alternatively activated macrophages (AAMs) play essential roles in the promotion of tissue remodeling, vasculogenesis, and tumor progression; however, the detailed mechanisms underlying the activation of AAMs remain largely unknown. Here, by using quantitative proteomic analysis, we identified 62 proteins that were up-regulated in IL-4-induced macrophages. Among these, Caspase-6 was increased significantly. Caspase-6 is important in the apoptotic signaling pathway; however, its role in non-apoptosis is also reported. Here, we first examined the non-apoptotic role of Caspase-6 in the alternative activation of macrophages after administration of IL-4, 4T1 tumor conditional medium, or co-culture with 4T1 cells. Both treatments promoted alternative activation of RAW264.7 cells and primary macrophages, whereas disruption of caspase-6 expression and activity could markedly suppress the biomarker levels of AAMs. Overexpression of Caspase-6 could significantly promote the activation of AAMs. Importantly, we further present evidence that caspase-6 could regulate breast cancer cell invasion by modulating MMP-2 and MMP-9 expression in 4T1 tumor-associated macrophages, as ablation of protein levels or activity of caspase-6 suppressed tumor cell invasion in vitro In conclusion, the observed results markedly expanded our views of the dynamic changes in protein composition during alternative activation of macrophages, and they revealed a critical new role of caspase-6 in regulating this cellular biological process, which suggested that caspase-6 might be a key nod molecule to regulate immunological steady-state and be a therapeutic candidate for tumor immunotherapy.
交替活化巨噬细胞（AAMs）在促进组织重塑、血管生成和肿瘤进展中发挥着重要作用；然而，AAMs活化的详细机制仍 largely未知。在这里，通过定量蛋白质组学分析，我们鉴定出62种在IL-4诱导的巨噬细胞中上调的蛋白质。其中，半胱天冬酶-6显著增加。半胱天冬酶-6在凋亡信号通路中很重要；然而，其在非凋亡中的作用也有报道。在这里，我们首先研究了在给予IL-4、4T1肿瘤条件培养基或与4T1细胞共培养后，半胱天冬酶-6在巨噬细胞交替活化中的非凋亡作用。两种处理均促进了RAW264.7细胞和原代巨噬细胞的交替活化，而半胱天冬酶-6表达和活性的破坏可显著抑制AAMs的生物标志物水平。半胱天冬酶-6的过表达可显著促进AAMs的活化。重要的是，我们进一步提供证据表明，半胱天冬酶-6可通过调节4T1肿瘤相关巨噬细胞中MMP-2和MMP-9的表达来调节乳腺癌细胞的侵袭，因为半胱天冬酶-6蛋白水平或活性的缺失在体外抑制了肿瘤细胞的侵袭。总之，观察结果显著扩展了我们对巨噬细胞交替活化过程中蛋白质组成动态变化的认识，并且揭示了半胱天冬酶-6在调节这一细胞生物学过程中的关键新作用，这表明半胱天冬酶-6可能是调节免疫稳态的关键节点分子，并且是肿瘤免疫治疗的候选靶点。
