Functional Interplay Between Type I Collagen and Cell Surface Matrix Metalloproteinase Activity.

Type I collagen stimulation of pro-matrix metalloproteinase (pro-MMP)-2 activation by ovarian cancer cells involves beta(1) integrin receptor clustering; however,the specific cellular and biochemical events that accompany MMP processing are not well characterized. Collagenolysis is not required for stimulation of pro-MMP-2 activation,and denatured collagen does not elicit an MMP-2 activation response. Similarly,DOV13 cells bind to intact collagen utilizing both alpha(2)beta(1) and alpha(3)beta(1) integrins but interact poorly with collagenase-treated or thermally denatured collagen. Antibody-induced clustering of alpha(3)beta(1) strongly promotes activation of pro-MMP-2,whereas alpha(2)beta(1) integrin clustering has only marginal effects. Membrane-type 1 (MT1)-MMP is present on the DOV13 cell surface as both an active 55-kDa TIMP-2-binding species and a stable catalytically inactive 43-kDa form. Integrin clustering stimulates cell surface expression of MT1-MMP and co-localization of the proteinase to aggregated integrin complexes. Furthermore,cell surface proteolysis of the 55-kDa MT1-MMP species occurs in the absence of active MMP-2,suggesting MT1-MMP autolysis. Cellular invasion of type I collagen matrices requires collagenase activity,is blocked by tissue inhibitor of metalloproteinases-2 (TIMP-2) and collagenase-resistant collagen,is unaffected by TIMP-1,and is accompanied by pro-MMP-2 activation. Together,these data indicate that integrin stimulation of MT1-MMP activity is a rate-limiting step for type I collagen invasion and provide a mechanism by which this activity can be down-regulated following collagen clearance.