Pericellular activation of hepatocyte growth factor by the transmembrane serine proteases matriptase and hepsin, but not by the membrane-associated protease uPA

Abstract

HGF (hepatocyte growth factor) is a pleiotropic cytokine homologous to the serine protease zymogen plasminogen that requires canonical proteolytic cleavage to gain functional activity. The activating proteases are key components of its regulation, but controversy surrounds their identity. Using quantitative analysis we found no evidence for activation by uPA (urokinase plasminogen activator), despite reports that this is a principal activator of pro-HGF. This was unaffected by a wide range of experimental conditions, including the use of various molecular forms of both HGF and uPA, and the presence of uPAR (uPA receptor) or heparin. In contrast the catalytic domains of the TTSPs (type-II transmembrane serine proteases) matriptase and hepsin were highly efficient activators (50% activation at 0.1 and 3.4 nM respectively), at least four orders of magnitude more efficient than uPA. PS-SCL (positional-scanning synthetic combinatorial peptide libraries) were used to identify consensus sequences for the TTSPs, which in the case of hepsin corresponded to the pro-HGF activation sequence, demonstrating a high specificity for this reaction. Both TTSPs were also found to be efficient activators at the cell surface. Activation of pro-HGF by PC3 prostate carcinoma cells was abolished by both protease inhibition and matriptase-targeting siRNA (small interfering RNA), and scattering of MDCK (Madin-Darby canine kidney) cells in the presence of pro-HGF was abolished by inhibition of matriptase. Hepsin-transfected HEK (human embryonic kidney)-293 cells also activated pro-HGF. These observations demonstrate that, in contrast with the uPA/uPAR system, the TTSPs matriptase and hepsin are direct pericellular activators of pro-HGF, and that together these proteins may form a pathway contributing to their involvement in pathological situations, including cancer.

MET signalling: principles and functions in development, organ regeneration and cancer

“…During tissue repair and cancer invasion, several cytokines that are abundant in the reactive interstitial compartment -for example, interleukin-1 and -6, tumour necrosis factor-α and transforming growth factor-β (TGFβ) -induce transcriptional upregulation of both HGF (in fibroblasts and resident macrophages) and MET (in epithelial cells) 33,34 . The inflammatory and tumour stroma also overexpress proteases that are involved in pro-HGF activation, such as the plasminogen activation system and matriptase 35,36 . Thus, biologically competent HGF is not only overproduced but also fully activated.…”

SPINT2 Deregulation in Prostate Carcinoma

“…Matriptase and hepsin have been implicated in the degradation of matrix components and transmembrane molecules, as well as in the modulation of cell-substratum adhesion (Del Rosso et al 2002). Moreover, matriptase, hepsin and HGFA are able to cleave pro-HGF into its active form, and thus trigger the HGF/c-MET signaling pathway, which is implicated in tumor growth, angiogenesis, invasion and metastasis (Benvenuti et al 2007;Owen et al 2010). …”

Glycosylation changes leading to the increase in size on the common core of N-glycans, required enzymes, and related cancer-associated proteins

“…The function of matriptase is associated with epithelial homeostasis in both health and disease situations (Gray et al, 2014). Matriptase participates in tumor growth and progression through the activation of 2 important cancer invasion effectors, hepatocyte growth factor (HGF) and urokinase plasminogen activator (uPA), on the surface of cancer cells (Qiu et al, 2007;Kotthaus et al, 2010;Owen et al, 2010). These proteins are involved in growth and motility of cancer cells, particularly carcinomas, and in the vascularization of tumors (Benaud et al, 2002).…”