Prinomastat, a hydroxamate inhibitor of matrix metalloproteinases, has a complex effect on migration of breast carcinoma cells

Abstract

Membrane type-1 matrix metalloproteinase (MT1-MMP) and αvβ3 integrin have been directly implicated in tumor cell dissemination and metastasis. We have demonstrated that in the case of breast carcinoma MCF7 cells co-expressing MT1-MMP and αvβ3 integrin, the proteinase processes the pro-αv integrin subunit, thus facilitating αvβ3 integrin maturation and cell migration on vitronectin. Our findings show that cell surface MT1-MMP is a short-lived protein with a life span in the range of several hours. In contrast, turnover of αvβ3 integrin is much slower. The half-life of αvβ3 heterodimer is about 24 hr. This large difference in life span allowed us to distinguish between the effects of MT1-MMP on cell migration brought by matrix proteolysis from those imposed through αvβ3 integrin maturation. We then modulated the enzyme's activity by a potent hydroxamate MMP inhibitor, Prinomastat (AG3340), to analyze the divergent effects of MT1-MMP on cell migration. Although Prinomastat immediately blocked MT1-MMP-mediated matrix degradation, the pool of MT1-MMP-modified αvβ3 integrin molecules was still capable of mediating cell-matrix interactions. To our considerable surprise, inhibition of MT1-MMP-dependent vitronectin proteolysis by Prinomastat allowed a several-fold increase in migration of MCF7 cells co-expressing MT1-MMP and αvβ3 integrin. In contrast, long-term Prinomastat inhibition of MT1-MMP-dependent pro-αv cleavage and thus αvβ3 integrin maturation strongly inhibited cell motility. Our studies suggest that MT1-MMP could actually promote cell migration via modification of the cell surface receptors, including αvβ3 integrin, rather than facilitate cell migration through direct cleavage of the matrix proteins. © 2003 Wiley-Liss, Inc.