Small leucine-rich proteoglycans and matrix metalloproteinase-14: Key partners?

Small leucine-rich proteoglycans (SLRPs) are important regulators of extracellular matrix assembly and cell signaling. They are a family of proteoglycans that are present in extracellular matrix and that share in common multiple repeats of a leucine-rich structural motif. SLRPs have been identified as inhibitors of cancer progression by affecting MMPs, especially MMP-14 activity. Lumican, a member of the SLRPs family, and its derived peptides were shown to possess anti-tumor activity. Interestingly, it was demonstrated recently that lumican interacts directly with the catalytic domain of MMP-14 and inhibits its activity. The aim of this review was to summarize the interactions between SLRPs and MMPs with a special interest to lumican.