Identification of Caspase-6 as a new regulator of alternatively activated macrophages

Yongfang Yao, Qian Shi, Bing Chen, Qingsong Wang, Xinda Li, Long Li, Yahong Huang, Jianguo Ji, Pingping Shen

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)17450-17466
Number of pages17
JournalJournal of Biological Chemistry
Volume291
Issue number33
DOIs
StatePublished - Aug 12 2016

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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