Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.73 (urokinase-type plasminogen activator)
 10,685 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tumour progression to the metastatic phenotype is mainly dependent on tumour cell invasiveness. Cell migration is a crucial step in this process. Here we investigate the effect of hepatocyte growth factor (HGF) on the induction of in vitro invasiveness of poorly aggressive Caco-2 colonic cancer epithelial cells. Invasion assays through a Matrigel barrier were performed. Proteases were assessed by zymography, reverse transcription-polymerase chain reaction and immunoblotting. Caco-2 cells were found to express HGF receptor but not HGF and to secrete several proteases, namely matrix metalloproteinase-1 (MMP-1), MMP-2, possibly MMP-9 and urokinase plasminogen activator (uPA). Exogenous HGF promoted invasiveness of Caco-2 cells through an artificial basement membrane matrix and enhanced their production of proteases. In addition, analyses of media at the end of invasion assays indicated that anti-HGF antibody inhibited protease production in parallel with cell invasion. The involvement of proteases in the HGF-induced invasion process was further investigated using either a synthetic general MMP inhibitor or neutralizing antibodies against MMPs or uPA. All components significantly inhibited HGF-promoted cell invasion. Moreover, specific inhibitors of PKCalpha/beta1 and PI3 kinase also decreased both HGF-promoted cell invasion and protease expression in invasion assay media. Thus, our findings provide evidence that the process of HGF-activated invasiveness of Caco-2 cells involves PI3 kinase and PKC and results from close association of two events, stimulation of cell motile activity and concomitant overproduction of proteases, which permits cell migration through a degraded extracellular matrix.
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PMID:Hepatocyte growth factor induces colonic cancer cell invasiveness via enhanced motility and protease overproduction. Evidence for PI3 kinase and PKC involvement. 1140 46

Components of the extracellular matrix take part in tissue rebuilding as well as activating surface-bound growth factors. In the present study, expression and selected activities of urokinase-type plasminogen activator (uPA), matrix metalloproteinases (MMPs), their inhibitors (plasminogen activator inhibitor 1 (PAI-1) and tissue inhibitors of metalloproteinases (TIMPs)) were examined in bovine oviducts by RT--PCR, ribonuclease protection assay and activity assays. A high content of mRNA encoding for uPA was detected before ovulation with a three-fold decrease after ovulation. In contrast, PAI-1 expression appeared to be stable during the oestrous cycle. Oviductal flushings produced caseinolytic zones in zymograms containing plasminogen at approximately 50 kDa and 28 kDa. An activity assay for uPA showed highest net activity during the early to mid-luteal phase. Increased TIMP-1 and MMP-2 mRNA concentrations were found around the time of ovulation compared with the luteal phase. In contrast, MMP-1 mRNA transcripts were enriched during the early to mid-luteal phase. Gelatin zymograms detected a 70--72 kDa protease activity showing an oestrous cycle-dependent activity with highest activity before ovulation. Reverse zymography detecting TIMPs revealed proteins between 21 kDa and 24 kDa. Only for the smallest (21 kDa) protein were amounts increased around the time of ovulation compared with the luteal phase. The observation that several extracellular matrix components were regulated distinctly in bovine oviducts indicates that local interactions between these components, growth factors, gametes and the embryo are possible and may influence fertilization and early embryonic development.
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PMID:Differential expression of extracellular matrix components in the bovine oviduct during the oestrous cycle. 1142 36

Transforming growth factor beta1 (TGF-beta1) and matrix metalloproteinases (MMPs) produced by tumor cells play important roles in tumor invasion. PSK, a protein-bound polysaccharide, is widely used in Japan as an immunopotentiating biological response modifier for cancer patients. In this study, we focused on the effects of PSK on invasiveness, TGF-beta1 production, and MMPs expression in two human tumor cell lines, pancreatic cancer cell line (NOR-P1) and gastric cancer cell line (MK-1P3). PSK significantly decreased the invasiveness of both cell lines through Matrigel-coated filters but did not affect cell viability, proliferation, or adhesion. Decreased invasion was associated with the inhibition of TGF-beta1, MMP-2, and MMP-9 at both mRNA and protein levels as assessed by reverse transcriptase-polymerase chain reaction, gelatin zymography, and enzyme-linked immunosorbent assay. Antibody against TGF-beta1 neutralized the MMP activities of both cell lines. PSK also suppressed the expression of urokinase plasminogen activator (uPA) and uPA receptor but did not change plasminogen activator inhibitor-1 (PAI-1) expression. Western blot analysis showed that PSK reduced uPA protein expression but not PAI-1 expression in the both cell lines. These results indicate that PSK suppresses tumor cell invasiveness through down-regulation of several invasion-related factors including TGF-beta1, uPA, MMP-2, and MMP-9.
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PMID:Protein-bound polysaccharide PSK inhibits tumor invasiveness by down-regulation of TGF-beta1 and MMPs. 1144 66

Previous studies have shown that matrix vesicles isolated from cultures of costochondral growth zone chondrocytes and treated with 1alpha,25-dihydroxyvitamin D3 [1alpha,25(OH)2D3] can activate recombinant human latent transforming growth factor beta1 (rhTGF-beta1). It is unknown what enzyme or other factor in the extracellular organelles is responsible for the activation. This study tested the hypothesis that enzymes present in matrix vesicles can activate latent TGF-beta1 and that this is regulated by 1alpha,25(OH)2D3. To do this, we examined the ability of matrix vesicle extracts to activate small latent rhTGF-beta1. In addition, enzymes previously determined to be present in matrix vesicles were screened for their ability to activate small latent rhTGF-beta1. Recombinant human matrix metalloproteinase 2 (rhMMP-2; 72 kDa gelatinase), rhMMP-3 (stromelysin 1), purified human plasminogen, and purified urokinase (plasminogen activator) were each tested at varying concentrations. To assess the role of cell maturation, we used a cell culture model in which chondrocytes are derived from two distinct zones of rat costochondral cartilage, the resting zone and the growth zone. Matrix vesicles were isolated from these cultures and then tested. The results showed that extracts of matrix vesicles produced by both growth zone and resting zone chondrocytes were able to activate small latent rhTGF-beta1. The effects were dose and time dependent, with greater activity being found in extracts of matrix vesicles from the growth zone chondrocyte cultures. Only rhMMP-3 was able to activate small latent rhTGF-beta1, indicating that stromelysin-1, but not MMP-2, plasminogen, or urokinase, was involved. As observed in the extracts, the effect of rhMMP-3 was time and dose dependent. When anti-MMP-3 antibody was added to matrix vesicle extracts from both cell types, activation of small latent rhTGF-beta1 was dose-dependently blocked. Neither 1alpha,25(OH)2D3 nor 24R,25(OH)2D3 had a direct effect on activation of small latent rhTGF-beta1 by the extracts. However, when intact matrix vesicles were treated with 1alpha,25(OH)2D3, their ability to activate small latent rhTGF-beta1 was increased. Inhibition of phospholipase A2 with quinacrine blocked the 1alpha,25(OH)2D3-dependent effect. These results suggest that the ability of 1alpha,25(OH)2D3-treated matrix vesicles to activate small latent TGF-beta1 is via action of the secosteroid on the matrix vesicle membrane, not on the enzymes responsible for activating latent TGF-beta1. Because matrix vesicles isolated from growth zone chondrocytes have been shown to contain increased phospholipase A2 activity after treatment with 1alpha,25(OH)2D3, it is likely that this secosteroid promotes loss of membrane integrity through phospholipase A2-dependent formation of lysophospholipids, resulting in the release of MMP-3 into the matrix, where latent TGF-beta1 is stored. Taken together, the results of the current study show that matrix vesicles produced by growth plate chondrocytes contain MMP-3, that this enzyme is at least partially responsible for activation of small latent TGF-beta1 in the matrix, and that 1alpha,25(OH)2D3 regulates MMP release from matrix vesicles.
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PMID:Activation of latent transforming growth factor beta1 by stromelysin 1 in extracts of growth plate chondrocyte-derived matrix vesicles. 1145 Jul 4

Extracellular proteolysis is an absolute requirement for new blood vessel formation (angiogenesis). This review examines the role of the matrix metalloproteinase (MMP) and plasminogen activator (PA)-plasmin systems during angiogenesis. Specifically, a role for gelatinases (MMP-2, MMP-9), membrane-type 1 MMP (MMP-14), the urokinase-type PA receptor, and PA inhibitor 1 has been clearly defined in a number of model systems. The MMP and PA-plasmin systems have also been implicated in experimental vascular tumor formation, and their role during this process will be examined. Antiproteolysis, particularly in the context of angiogenesis, has become a key target in therapeutic strategies aimed at inhibiting tumor growth and other diseases associated with neovascularization.
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PMID:Role of the matrix metalloproteinase and plasminogen activator-plasmin systems in angiogenesis. 1145 38

The effects of tumor necrosis factor (TNF)-alpha on the plasminogen activator (PA)/plasmin system in human dental pulp (HDP) cells were examined. TNF-alpha treatment induced a significantly high level of PA activity in the conditioned medium of HDP cells in a time- and dose-dependent manner, compared with untreated control cells. Western-blot analysis revealed that tissue type (t)PA protein in conditioned medium was increased by TNF-alpha when compared with control medium. Furthermore the tPA mRNA level had increased in HDP cells treated with TNF-alpha, as determined by reverse transcription-polymerase chain reaction, but urokinase PA and PA inhibitor-1 mRNA levels did not increase. We examined the effects of TNF-alpha against activities of matrix metalloproteinases (MMPs) using zymography. TNF-alpha stimulated MMP-2 activity in conditioned medium and stimulated MMP-9 activity with addition of plasminogen into conditioned medium. The present results suggested that TNF-alpha stimulates PA activity via an enhancement of tPA gene expression in HDP cells and MMP-2 activity, and further that tPA-activated TNF-alpha stimulated MMP-9.
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PMID:Stimulation of plasminogen activator activity and matrix metalloproteinases of human dental pulp-derived cells by tumor necrosis factor-alpha. 1148 46

Proteases are linked to the malignant phenotype of different solid tumors. Therefore, the expression of the matrix metalloproteinase (MMP)-2 and MMP-9 and of the serine protease urokinase-type plasminogen activator (uPA) and its inhibitor plasminogen activator inhibitor type 1 (PAI-1) in the progression of ovarian cancer was investigated. Gelatinolytic activity and protein expression of MMP-2 and MMP-9 were analyzed in tissue extracts of 19 cystadenomas and 18 low malignant potential (LMP) tumors, as well as 41 primary tumors of advanced ovarian cancer stage International Federation of Gynecology and Obstetrics IIIc/IV and their corresponding omentum metastases by quantitative gelatin zymography and Western blot. In the same tissue extracts, antigen levels of uPA and its inhibitor PAI-1 were determined by ELISA. Protein expression of pro-MMP-2 (72 kDa) and pro-MMP-9 (92 kDa as well as antigen levels of uPA and PAI-1 were low in benign ovarian tumors but increased significantly from LMP tumors to advanced ovarian cancers. The highest values of all of the proteolytic factors were detected in omentum metastases. Active MMP-2 enzyme (62 kDa) was detected only in ovarian cancer (66%) and corresponding metastases (93%) but never in benign or LMP tumors. The activation rate of MMP-2 to its active isoform was higher in the metastases. Comparing both proteolytic systems, higher PAI-1 concentrations were consistently found in cancers with high pro-MMP-9 expression. These data indicate that members of the plasminogen activator system, as well as the metalloproteinases MMP-2/9, increase with growing malignant potential of ovarian tumors. These findings are of particular relevance to the development of protease inhibitors as new therapeutic approaches in ovarian cancer.
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PMID:Increased expression of matrix metalloproteinases (MMP)-2, MMP-9, and the urokinase-type plasminogen activator is associated with progression from benign to advanced ovarian cancer. 1148 18

We investigated the effect of TGF-beta1 on liver metastasis of pancreatic cancer using surgical specimens of pancreatic cancer and human pancreatic cancer cell lines Capan-2 and SW1990. Immunostaining of TGF-beta1 showed that TGF-beta1 positivity was significantly related to venous invasion and tumor staging, and also relatively associated with liver metastasis. Cellular invasion and protease production of MMP-2 and u-PA, and in vivo liver metastasis were significantly enhanced after treatment of cells with TGF-beta1. These findings suggest that TGF-beta1 might play an important role in enhancing liver metastasis of pancreatic cancer.
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PMID:TGF-beta1 promotes liver metastasis of pancreatic cancer by modulating the capacity of cellular invasion. 1156 45

Circumstantial evidence has suggested an important role of the fibrinolytic (plasminogen/plasmin) and matrix metalloproteinase (MMP) systems in biological processes involving (extra)cellular proteolysis and/or matrix degradation, such as restenosis after vascular interventions in patients with atherothrombosis. The generation of mice with inactivation of main components of both systems and of suitable experimental models has allowed to study the interactions between both systems and their biological role in arterial neointima formation after vascular injury. During neointima formation after electric injury of the femoral artery, expression of MMP-2 and MMP-9 (gelatinase A and B) is strongly enhanced, independently of the presence or absence of plasminogen or of the physiological tissue-type (t-PA) or urokinase-type (u-PA) plasminogen activators. Activation of proMMP-2 occurs independently of plasmin, whereas proMMP-9 activation occurs via plasmin-dependent as well as plasmin-independent (MMP-3- or stromelysin-1-dependent) mechanisms. The temporal and topographic expression patterns of MMP-2, MMP-3, MMP-9, MMP-12 (metalloelastase) and MMP-13 (collagenase) after vascular injury are compatible with a role of MMPs in neointima formation. This is further substantiated by the finding that smooth muscle cell (SMC) migration and neointima formation after vascular injury is significantly enhanced in mice with deficiency of TIMP-1, the main physiological MMP inhibitor. In contrast, arterial neointima formation in mice is not affected by deficiency of alpha 2-antiplasmin, the main physiological plasmin inhibitor. Thus, SMC migration and neointima formation after vascular injury appear to be promoted by several MMP system components, that may be activated via plasmin-dependent or plasmin-independent mechanisms.
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PMID:Role of the fibrinolytic and matrix metalloproteinase systems in arterial neointima formation after vascular injury. 1181 12

Degradation of the extracellular matrix leads to the release of fragments, which elicit biological responses distinct from intact molecules. We have reported that alpha1:Ser(2091)-Arg(2108), a peptide derived from the alpha1-chain of laminin-1, triggers protein kinase C-dependent activation of MAPK(erk1/2), leading to the up-regulation of macrophage urokinase type plasminogen activator and matrix metalloproteinase (MMP)-9 expression. Since intact laminin-1 failed to trigger these events, we hypothesized that alpha1:Ser(2091)-Arg(2108) is cryptic or assumes a conformation not recognized by macrophages. Here we demonstrate that elastase cleavage of laminin-1 generates fragments, which stimulate proteinase expression by RAW264.7 macrophages and peritoneal macrophages. In contrast, fragments generated by MMP-2, MMP-7, or plasmin had no effect on macrophage proteinase expression. Elastase-generated laminin-1 fragments were fractionated by heparin-Sepharose chromatography. Heparin-binding fragments stimulated macrophages' proteinase expression severalfold greater than nonbinding fragments. The heparin binding fragments reacted with antibodies directed against regions of the alpha1-chain including alpha1:Ser(2091)-Arg(2108) and the globular domain. A peptide from the first loop of the globular domain (alpha1:Ser(2179)-Ser(2198)) triggered the phosphorylation of MAPK(erk1/2) and stimulated the expression of macrophage urokinase type plasminogen activator and MMP-9. Moreover, a heparin-binding fraction isolated from an aortic aneurysm contained fragments of alpha1-chain and stimulated macrophages' proteinase expression. Based on these data, we conclude that cryptic domains in the COOH-terminal portion of the alpha1-chain of laminin are exposed by proteolysis and stimulate macrophages' proteinase expression.
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PMID:Exposure of cryptic domains in the alpha 1-chain of laminin-1 by elastase stimulates macrophages urokinase and matrix metalloproteinase-9 expression. 1182 68


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