title: Selective modulation of matrix metalloproteinase 9 (MMP-9) functions via exosite inhibition.
abstract: Unregulated activities of the matrix metalloproteinase (MMP) family have been implicated in primary and metastatic tumor growth, angiogenesis, and pathological degradation of extracellular matrix components, such as collagen and laminin. However, clinical trials with small molecule MMP inhibitors have been largely unsuccessful, with a lack of selectivity considered particularly problematic. Enhanced selectivity could be achieved by taking advantage of differences in substrate secondary binding sites (exosites) within the MMP family. In this study, triple-helical substrates and triple-helical transition state analog inhibitors have been utilized to dissect the roles of potential exosites in MMP-9 collagenolytic behavior. Substrate and inhibitor sequences were based on either the alpha1(V)436-450 collagen region, which is hydrolyzed at the Gly (downward arrow) Val bond selectively by MMP-2 and MMP-9, or the Gly (downward arrow) Leu cleavage site within the consensus interstitial collagen sequence alpha1(I-III)769-783, which is hydrolyzed by MMP-1, MMP-2, MMP-8, MMP-9, MMP-13, and MT1-MMP. Exosites within the MMP-9 fibronectin II inserts were found to be critical for interactions with type V collagen model substrates and inhibitors and to participate in interactions with an interstitial (types I-III) collagen model inhibitor. A triple-helical peptide incorporating a fibronectin II insert-binding sequence was constructed and found to selectively inhibit MMP-9 type V collagen-based activities compared with interstitial collagen-based activities. This represents the first example of differential inhibition of collagenolytic activities and was achieved via an exosite-binding triple-helical peptide.
authors.affiliation: Department of Chemistry and Biochemistry and College of Biomedical Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA.
authors.forename: Janelle L
authors.initials: JL
authors.lastname: Lauer-Fields
authors.forename: John K
authors.initials: JK
authors.lastname: Whitehead
authors.forename: Shunzi
authors.initials: S
authors.lastname: Li
authors.forename: Robert P
authors.initials: RP
authors.lastname: Hammer
authors.forename: Keith
authors.initials: K
authors.lastname: Brew
authors.forename: Gregg B
authors.initials: GB
authors.lastname: Fields
mesh_terms: D001665:Binding Sites; D004791:Enzyme Inhibitors / Q000494:pharmacology; D017353:Gene Deletion; D007700:Kinetics; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism*; D061965:Matrix Metalloproteinase Inhibitors; D009154:Mutation / Q000235:genetics; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D004791:Enzyme Inhibitors; D061965:Matrix Metalloproteinase Inhibitors; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9