Ovarian carcinoma regulation of matrix metalloproteinase-2 and membrane type 1 matrix metalloproteinase through beta 1 integrin

Culturing DOV 13 ovarian carcinoma cells on three-dimensional collagen latt ice but not on thin-layer collagen induces processing of promatrix metallop roteinase (MMP)-2 to a M-r 62,000 form, suggesting that multivalent integri n aggregation may participate in proteinase regulation. To address the role of collagen-binding integrins in this event, we treated DOV 13 cells with soluble beta 1 integrin antibodies (clones P4C10 or 21C8) or pi integrin an tibodies immobilized on latex beads to promote integrin aggregation. Divale nt ligation of beta 1 integrins with soluble P4C10 antibodies stimulated ex pression of pro-MMP-2 and its inhibitor, tissue inhibitor of metalloprotein ase-2, whereas soluble 21C8 antibodies had no effect. Aggregation of beta 1 integrins with immobilized 21C8 or P4C10 antibodies stimulated MMP-depende nt pro-MMP-2 activation and accumulation of a M-r 43,000 form of membrane t ype 1 MMP (MT1-MMP), a cell surface activator of pro-MMP-2 in cell extracts . beta 1 integrin-mediated MMP-2 activation required protein synthesis and tyrosine kinase signaling and was reduced by an inhibitor of gene transcrip tion. Treatment of control cells with concanavalin A stimulated MMP-depende nt pro-MMP-2 activation and accumulation of M-r 55,000 and 43,000 forms of MT1-MMP in cell extracts, Addition of either the MMP inhibitor GM-6001-X of exogenous tissue inhibitor of metalloproteinase-2 to concanavalin A-treate d cells resulted in loss of the M-r 43,000 form of MT1-MMP and accumulation of the M-r 55,000 form of the enzyme in cell extracts, suggesting that the M-r 43,000 form is a product of MMP-dependent M-r 55,000 MT1-MMP proteolys is. Together, these data suggest that pi integrin stimulation of pro-MMP-2 activation involves MT1-MMP posttranslational processing and requires multi valent integrin aggregation.