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)

Plasmin is essential for metalloproteases activation, endothelial cell migration and degradation of the extracellular matrix. The process is common to neoangiogenesis pannus formation and cartilage degradation within arthritic joints. Since 80% of synovial cells express urokinase plasminogen activator receptor (uPAR), we investigated the inhibition of plasmin activation in a collagen-induced arthritis (CIA) mice model, by expressing a uPA/uPAR antagonist molecule (ATF) fused to human serum albumin (HSA) to extend its serum half-life. Overexpression was obtained with an adenoviral vector expressing the chimeric murine ATF-HSA. We showed that the genetic coupling did not significantly reduce the ability of the ATF moiety to interact with its receptor uPAR. The chimeric protein was detectable in the sera of injected mice 7 days following Ad-mATF-HSA injection, then decreased in parallel with the anti-HSA titer increase. Systemic Ad-mATF-HSA injection performed on day 25 following CIA induction decreased the incidence of arthritis and the severity of the disease. Moreover, synovial angiogenesis in arthritic paws was decreased after Ad-mATF-HSA gene transfer, as assessed by smooth muscle actin immunostaining. The preventive effect observed on arthritis was related to the decrease in angiogenesis, rather than inhibition of extracellular matrix degradation.
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PMID:Adenovirus-mediated gene transfer of urokinase plasminogen inhibitor inhibits angiogenesis in experimental arthritis. 1185 22

Cell recruitment is a multistep process regulated by cytokines, chemokines, and growth factors. Previous work has indicated that the urokinase plasminogen activator receptor (uPAR) may also play a role in this mechanism, presumably by an interaction with the beta(2) integrin CD11b/CD18. Indeed, an essential role of uPAR in neutrophil recruitment during pulmonary infection has been demonstrated for beta(2) integrin-dependent respiratory pathogens. We investigated the role of uPAR and urokinase plasminogen activator (uPA) during pneumonia caused by a beta(2) integrin-independent respiratory pathogen, Streptococcus pneumoniae. uPAR-deficient (uPAR(-/-)), uPA-deficient (uPA(-/-)), and wild-type (Wt) mice were intranasally inoculated with 10(5) CFU S. pneumoniae. uPAR(-/-) mice showed reduced granulocyte accumulation in alveoli and lungs when compared with Wt mice, which was associated with more S. pneumoniae CFU in lungs, enhanced dissemination of the infection, and a reduced survival. In contrast, uPA(-/-) mice showed enhanced host defense, with more neutrophil influx and less pneumococci in the lungs compared with Wt mice. These data suggest that uPAR is necessary for adequate recruitment of neutrophils into the alveoli and lungs during pneumonia caused by S. pneumoniae, a pathogen eliciting a beta(2) integrin-independent inflammatory response. This function is even more pronounced when uPAR is unoccupied by uPA.
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PMID:Urokinase receptor is necessary for adequate host defense against pneumococcal pneumonia. 1190 12

The process of muscle regeneration in normal and dystrophic muscle depends on locally produced cytokines and growth factors and requires the activity of the urokinase plasminogen activator/urokinase plasminogen activator receptor/plasminogen activator inhibitor-1 system. In this study we tested the effect of basic fibroblast growth factor (bFGF), hepatocyte growth factor (HGF) and transforming growth factor-beta (TGFbeta) on the fibrinolytic pattern of normal and dystrophic satellite cells, their mitogenic and motogenic activities and the dependence of such activities on the cell-associated fibrinolytic system. We have observed that the urokinase plasminogen activator (u-PA) receptor is weakly upregulated by bFGF in normal satellite cells, while it is strongly up-regulated by TGFbeta, mainly in dystrophic myoblasts. bFGF up-regulated u-PA in both normal and dystrophic myoblasts grown in primary culture, while a striking down-regulation was observed with TGFbeta. TGFbeta was the only growth factor able to exceptionally up-regulate plasminogen activator inhibitor-1 (PAI-1), mainly in dystrophic satellite cells. HGF did not show any activity on the fibrinolytic system. Proliferation and invasion into Matrigel matrices of normal and dystrophic cells occurred regardless of the growth factor-dependent regulation of the fibrinolytic system. Nevertheless, each growth factor required the efficiency of the constitutive cell-associated fibrinolytic system to operate, as shown by impairment of growth factor activity with antagonists of u-PA and of its receptor. Noteworthy, TGFbeta induced a dose-dependent increase of Matrigel invasion only in dystrophic myoblasts. Since TGFbeta-challenged dystrophic myoblasts undergo an exceptional up-regulation of the receptor and of PAI-1, we propose the possibility that the TGFbeta-induced fibrinolytic pattern (low urokinase plasminogen activator, high receptor and high PAI-1) may be exploited to promote survival and spreading of transplanted engineered myoblasts in Duchenne muscular dystrophy.
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PMID:Growth factor-dependent proliferation and invasion of muscle satellite cells require the cell-associated fibrinolytic system. 1192 7

Cell migration is a complex process requiring tight control of several mechanisms including dynamic reorganization of the actin cytoskeleton and adhesion to the extracellular matrix. The GPI-anchored urokinase plasminogen activator receptor (uPAR) has an important role in the regulation of cell motility in many cell types. This is partly due to the localization of proteolytic activity on the cell surface by binding of the serine protease uPA. Results accumulated over the last decade suggest that uPAR is also involved in motility control through other mechanisms. These include induction of signal transduction events after ligation with uPA, binding to the extracellular matrix molecule vitronectin (VN), and association with integrins and other transmembrane partners. In this review these mechanisms will be discussed with a special emphasis on how the GPI-linked receptor transmits signals to the intracellular milieu and how uPAR participates in the regulation of actin cytoskeleton reorganization and cell adhesion during cell migration.
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PMID:The urokinase plasminogen activator receptor in the regulation of the actin cytoskeleton and cell motility. 1192 22

A novel alpha-particle emitting ((213)Bi) plasminogen activator inhibitor type 2 construct, which targets the membrane-bound urokinase plasminogen activator on prostate cancer cells, was prepared and evaluated in vitro and in a xenograft animal model. The PC3 prostate cancer cell line expresses urokinase plasminogen activator which binds to its receptor on the cell membrane; plasminogen activator inhibitor type 2 is bound to urokinase plasminogen activator/urokinase plasminogen activator receptor to form stable complexes. In vitro, the cytotoxicity of (213)Bi-plasminogen activator inhibitor type 2 against prostate cancer cells was tested using the MTS assay and apoptosis was documented using terminal deoxynucleotidyl transferase-mediated deoxyuridinetriphosphate nick end-labelling (TUNEL) assay. In vivo, antiproliferative effects for tumours and prostate cancer lymph node metastasis were carried out in an athymic nude mouse model with a subcutaneous xenograft of PC3 cells. (213)Bi-plasminogen activator inhibitor type 2 was specifically cytotoxic to PC3 cells in a concentration-dependent fashion, causing the cells to undergo apoptosis. A single local or i.p. injection of (213)Bi-plasminogen activator inhibitor type 2 was able to completely regress the growth of tumours and lymph node metastases 2 days post subcutaneous inoculation, and obvious tumour regression was achieved in the therapy groups compared with control groups with (213)Bi-plasminogen activator inhibitor type 2 when the tumours measured 30-40 mm(3) and 85-100 mm(3). All control animals and one of five (20%) mice treated with 3 mCi kg(-1) (213)Bi-plasminogen activator inhibitor type 2 developed metastases in the lymph nodes while no lymphatic spread of cancer was found in the 6 mCi kg(-1) treated groups at 2 days and 2 weeks post-cell inoculation. These results demonstrate that this novel (213)Bi-plasminogen activator inhibitor type 2 conjugate selectively targets prostate cancer in vitro and in vivo, and could be considered for further development for the therapy of prostate cancer, especially for the control of micro-metastases or in minimal residual disease.
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PMID:213Bi-PAI2 conjugate selectively induces apoptosis in PC3 metastatic prostate cancer cell line and shows anti-cancer activity in a xenograft animal model. 1195 71

Pericellular proteolysis plays a crucial role in tumor cell invasion. The controlled degradation of the extracellular matrix by tumor cell-associated proteases allows tumor cells to invade surrounding tissues and gain access to the circulation. One of the main protease systems involved in tumor cell invasion and metastasis is the plasminogen/plasmin system (PPS). The components of the PPS include the urokinase plasminogen activator (uPA), its cell surface receptor urokinase plasminogen activator receptor (uPAR), and its naturally occurring inhibitors, plasminogen activator inhibitors 1 and 2 (PAI-1 and PAI-2). Increases in tumor and serum levels of uPA, uPAR, and PAI-1 are associated with a worse prognosis in patients with colon cancer. Use of these proteins as either tumor or serum markers may allow more accurate determination of the prognosis in colon cancer patients. Furthermore, these proteins appear to be attractive as targets for the biologic therapy of colon cancer.
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PMID:Plasmin/plasminogen system in colorectal cancer. 1196 42

The low density lipoprotein (LDL) receptor-related protein 1B (LRP1B) is a newly identified member of the LDL receptor family and is closely related to LRP. It was discovered as a putative tumor suppressor and is frequently inactivated in lung cancer cells. In the present study, we used an LRP1B minireceptor (mLRP1B4), which mimics the function and trafficking of LRP1B, to explore the roles of LRP1B on the plasminogen activation system. We found that mLRP1B4 and urokinase plasminogen activator receptor (uPAR) form immunoprecipitable complexes on the cell surface in the presence of complexes of uPA and its inhibitor, plasminogen activator inhibitor type-1 (PAI-1). However, compared with cells expressing the analogous LRP minireceptor (mLRP4), cells expressing mLRP1B4 display a substantially slower rate of uPA.PAI-1 complex internalization. Expression of mLRP1B4, or an mLRP4 mutant deficient in endocytosis, leads to an accumulation of uPAR at the cell surface and increased cell-associated uPA and PAI-1 when compared with cells expressing mLRP4. In addition, we found that expression of mLRP1B or the mLRP4 endocytosis mutant impairs the regeneration of unoccupied uPAR on the cell surface and that this correlates with a diminished rate of cell migration. Taken together, these results demonstrate that LRP1B can function as a negative regulator of uPAR regeneration and cell migration.
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PMID:Low density lipoprotein (LDL) receptor-related protein 1B impairs urokinase receptor regeneration on the cell surface and inhibits cell migration. 1219 87

Proteolytic cleavage of the urokinase plasminogen activator receptor (uPA(R)) prevents the binding of uPA and vitronectin while generating biologically active uPAR fragments. We have recently shown that matrix metalloproteinase-12 (MMP-12) releases cellular uPAR-antigen from stimulated human micro-vascular endothelial cells providing a novel feedback mechanism between the plasminogen activation and MMP systems. We now show that MMP-12 and other MMPs directly and efficiently cleave uPAR at the Thr86 paralal Tyr87 peptide bond located in the linker region connecting uPAR domains 1 and 2, releasing the major ligand binding domain 1 from the rest of the receptor. The possible biological importance of uPAR cleavage by MMPs is supported by the observation that also murine uPAR is cleaved by MMP-12 (at the Pro89 paralal Gln90 peptide bond), despite the limited sequence homology between the linker regions. Using an antibody raised against the human uPAR linker region we show that this region of uPAR, which contains the chemotactic SRSRY epitope, is exposed upon MMP cleavage.
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PMID:Metalloproteases cleave the urokinase-type plasminogen activator receptor in the D1-D2 linker region and expose epitopes not present in the intact soluble receptor. 1219 4

The expression of plasminogen- and colony-stimulating factor-1-associated markers was first investigated in seven bladder carcinoma cell lines and in 15 primary bladder tumors using RT-PCR (mRNAs), zymography (protein activity), ELISA and immunocytochemistry analysis (ICC) (protein levels). The mRNAs expression, the activity and the levels of the secreted proteins were not informative. Only urokinase plasminogen activator receptor (uPA-R/CD87) and possibly plasminogen activator inhibitor type-2 (PAI2) antigen expression at the cellular levels seem to be useful markers. uPA-R antigen expression correlated with the secretion of hepatocyte growth factor (HGF) ( P=0.016) and the motility of the bladder tumor cells ( P=0.014), two markers associated with a poor prognosis in bladder carcinoma. To validate our technique and confirm these preliminary results, uPA-R and PAI2 antigen expression was determined in the imprints from 129 resected bladder carcinoma fragments. uPA-R correlated with the grade ( P=0.002), tumor invasion ( P=0.003) and the ploidy ( P=0.05) of the bladder carcinomas and with the low overall survival ( P=0.045) of the patients. PAI2 correlated only with the stage ( P=0.02) and low overall survival ( P=0.038). We conclude that in bladder carcinomas, studying the transcripts of PAs, PAIs, CSF-1 and its receptor, as well as measuring their concentration or activity in culture supernatants was of no clinical interest in terms of diagnostic or prognostic value. Only the ICC of uPA-R, which correlated with the major histopathological parameters of tumors and the low overall survival, proved to be a diagnostic and prognostic marker.
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PMID:Plasminogen- and colony-stimulating factor-1-associated markers in bladder carcinoma: diagnostic value of urokinase plasminogen activator receptor and plasminogen activator inhibitor type-2 using immunocytochemical analysis. 1238 18

The urokinase receptor (urokinase plasminogen activator receptor; uPAR) regulates monocyte adhesion by direct binding to vitronectin and by forming complexes with integrins. Therefore, possible up-regulation of uPAR in acute myocardial infarction (AMI) may affect monocyte adhesion. In 20 patients with AMI, uPAR surface expression (measured by flow cytometry) was increased compared with that in patients with chronic stable angina (mean +/- SD fluorescence, 179 +/- 96 vs 80 +/- 53; P =.002). Expression of uPAR correlated with activation of beta(2)-integrins lymphocyte function-associated antigen 1 (LFA-1) and macrophage antigen 1 (Mac-1), measured by using monoclonal antibodies (mAbs) 24 and CBRM1/5. Isolated mononuclear cells (MNCs) from patients with AMI showed enhanced adhesiveness to human umbilical vein endothelial cells (HUVECs), to fibrinogen (Mac-1 ligand), and to vitronectin (uPAR ligand). Excessive adhesion of MNCs to HUVECs was inhibited by mAbs anti-CD18 (84%), anti-CD11a (51%), and anti-CD11b (57%), indicating a major contribution of LFA-1 and Mac-1. The mAb anti-uPAR R3 blocked adhesion of cells from patients with AMI to vitronectin (95%) but also beta(2)-integrin-mediated adhesion to fibrinogen (79%) and HUVECs (66%). Incubation of monocytic MonoMac6 cells with plasma from patients with AMI enhanced uPAR messenger RNA expression and cell adhesion to HUVECs. Thus, released soluble factors may contribute to enhanced monocyte adhesion in AMI. Mouse pre-B lymphocytes (BAF3 cells) transfected with various amounts of uPAR complementary DNA showed a strong correlation of uPAR expression with beta(2)-integrin-dependent adhesion to intercellular adhesion molecule 1, thus providing evidence for the functional relevance of uPAR up-regulation in an isolated in vitro system. In conclusion, we found that uPAR expression is elevated on monocytes in AMI and contributes to enhanced cell adhesion. Thus, uPAR may be a novel target for prevention of unwanted monocyte recruitment as part of inflammatory cardiovascular processes.
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PMID:Urokinase receptor surface expression regulates monocyte adhesion in acute myocardial infarction. 1239 44


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