A Transcriptional Regulatory Role for the Membrane Type-1 Matrix Metalloproteinase in Carcinogen-Induced Inflammasome...

Signal-transducing functions driven by the cytoplasmic domain of membrane type-1 matrix metalloproteinase (MT1-MMP) are believed to regulate many inflammation-associated cancer cell functions including migration, proliferation, and survival. Aside from upregulation of the inflammation biomarker cyclooxygenase-2 (COX-2) expression, MT1-MMP's role in relaying intracellular signals triggered by extracellular pro-inflammatory cues remains poorly understood. Here, we triggered inflammation in HT1080 fibrosarcoma cells with phorbol-12-myristate-13-acetate (PMA), an inducer of COX-2 and of MT1-MMP. To assess the global transcriptional regulatory role that MT1-MMP may exert on inflammation biomarkers, we combined gene array screens with a transient MT1-MMP gene silencing strategy. Expression of MT1-MMP was found to exert both stimulatory and repressive transcriptional control of several inflammasome-related biomarkers such as interleukin (IL)-1B, IL-6, IL-12A, and IL-33, as well as of transcription factors such as EGR1, ELK1, and ETS1/2 in PMA-treated cells. Among the signal-transducing pathways explored, the silencing of MT1-MMP prevented PMA from phosphorylating extracellular signal-regulated kinase, inhibitor of κB, and p105 nuclear factor κB (NF-κB) intermediates. We also found a signaling axis linking MT1-MMP to MMP-9 transcriptional regulation. Altogether, our data indicate a significant involvement of MT1-MMP in the transcriptional regulation of inflammatory biomarkers consolidating its contribution to signal transduction functions in addition to its classical hydrolytic activity.