1. Potent and specific inhibition of the biological activity of the type-II transmembrane serine protease matriptase by the cyclic microprotein MCoTI-II.
- Author
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Gray K, Elghadban S, Thongyoo P, Owen KA, Szabo R, Bugge TH, Tate EW, Leatherbarrow RJ, and Ellis V
- Subjects
- Animals, Cell Line, Tumor, Cell Movement drug effects, Dogs, Electric Impedance, HEK293 Cells, Hepatocyte Growth Factor metabolism, Humans, Madin Darby Canine Kidney Cells, Male, Molecular Targeted Therapy, Neoplasm Invasiveness, Prostatic Neoplasms enzymology, Prostatic Neoplasms pathology, Protein Precursors metabolism, Serine Endopeptidases genetics, Substrate Specificity, Tight Junctions drug effects, Tight Junctions enzymology, Time Factors, Transfection, Cyclotides pharmacology, Serine Endopeptidases metabolism, Serine Proteinase Inhibitors pharmacology
- Abstract
Matriptase is a type-II transmembrane serine protease involved in epithelial homeostasis in both health and disease, and is implicated in the development and progression of a variety of cancers. Matriptase mediates its biological effects both via as yet undefined substrates and pathways, and also by proteolytic cleavage of a variety of well-defined protein substrates, several of which it shares with the closely-related protease hepsin. Development of targeted therapeutic strategies will require discrimination between these proteases. Here we have investigated cyclic microproteins of the squash Momordica cochinchinensis trypsin-inhibitor family (generated by total chemical synthesis) and found MCoTI-II to be a high-affinity (Ki 9 nM) and highly selective (> 1,000-fold) inhibitor of matriptase. MCoTI-II efficiently inhibited the proteolytic activation of pro-hepatocyte growth factor (HGF) by matriptase but not by hepsin, in both purified and cell-based systems, and inhibited HGF-dependent cell scattering. MCoTI-II also selectively inhibited the invasion of matriptase-expressing prostate cancer cells. Using a model of epithelial cell tight junction assembly, we also found that MCoTI-II could effectively inhibit the re-establishment of tight junctions and epithelial barrier function in MDCK-I cells after disruption, consistent with the role of matriptase in regulating epithelial integrity. Surprisingly, MCoTI-II was unable to inhibit matriptase-dependent proteolytic activation of prostasin, a GPI-anchored serine protease also implicated in epithelial homeostasis. These observations suggest that the unusually high selectivity afforded by MCoTI-II and its biological effectiveness might represent a useful starting point for the development of therapeutic inhibitors, and further highlight the role of matriptase in epithelial maintenance.
- Published
- 2014
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