The Experts below are selected from a list of 8190 Experts worldwide ranked by ideXlab platform
Francesco Blasi - One of the best experts on this subject based on the ideXlab platform.
-
The Urokinase Receptor and the regulation of cell proliferation.
Thrombosis and haemostasis, 2005Co-Authors: Roberta Mazzieri, Francesco BlasiAbstract:The Urokinase Receptor is a multifunctional Receptor modulating both proteolytic dependent and independent processes. It binds the extracellular proteolytic enzyme Urokinase and engages lateral interactions with several transmembrane Receptors, including integrins and the EGFR. Both, by initiating a proteolytic cascade acting on the extracellular matrix components, and by regulating the activity of important signal transducers, uPAR participates not only in the modulation of cell-cell and cell-extracellular matrix interactions, but also in the control of extracellular signals determining the proliferative state of a cell. Alteration of such a complex and finely modulated mechanism results in unregulated cell proliferation and altered tissue organization, typically associated with tumor progression.
-
Urokinase Urokinase Receptor and vitronectin αvβ3 integrin induce chemotaxis and cytoskeleton reorganization through different signaling pathways
Oncogene, 2001Co-Authors: Bernard Degryse, Simone Orlando, Massimo Resnati, Shafaat A Rabbani, Francesco BlasiAbstract:Urokinase/Urokinase Receptor and vitronectin/α v β 3 integrin induce chemotaxis and cytoskeleton reorganization through different signaling pathways
-
Urokinase/Urokinase Receptor and vitronectin/αvβ3 integrin induce chemotaxis and cytoskeleton reorganization through different signaling pathways
Oncogene, 2001Co-Authors: Bernard Degryse, Simone Orlando, Massimo Resnati, Shafaat A Rabbani, Francesco BlasiAbstract:Urokinase/Urokinase Receptor and vitronectin/α v β 3 integrin induce chemotaxis and cytoskeleton reorganization through different signaling pathways
-
proteolytic cleavage of the Urokinase Receptor substitutes for the agonist induced chemotactic effect
The EMBO Journal, 1996Co-Authors: Massimo Resnati, Francesco Blasi, Nicolai Sidenius, M Guttinger, S Valcamonica, Francesca FazioliAbstract:Physiological concentrations of Urokinase plasminogen activator (uPA) stimulated a chemotactic response in human monocytic THP-1 through binding to the Urokinase Receptor (uPAR). The effect did not require the protease moiety of uPA, as stimulation was achieved also with the N-terminal fragment (ATF), while the 33 kDa low molecular weight uPA was ineffective. Co-immunoprecipitation experiments showed association of uPAR with intracellular kinase(s), as demonstrated by in vitro kinase assays. Use of specific antibodies identified p56/p59hck as a kinase associated with uPAR in THP-1 cell extracts. Upon addition of ATF, p56/p59hck activity was stimulated within 2 min and returned to normal after 30 min. Since uPAR lacks an intracellular domain capable of interacting with intracellular kinase, activation of p56/p59hck must require a transmembrane adaptor. Evidence for this was strongly supported by the finding that a soluble form of uPAR (suPAR) was capable of inducing chemotaxis not only in THP-1 cells but also in cells lacking endogenous uPAR (IC50, 5 pM). However, activity of suPAR require chymotrypsin cleavage between the N-terminal domain D1 and D2 + D3. Chymotrypsin-cleaved suPAR also induced activation of p56/p59hck in THP-1 cells, with a time course comparable with ATF. Our data show that uPA-induced signal transduction takes place via uPAR, involves activation of intracellular tyrosine kinase(s) and requires an as yet undefined adaptor capable of connecting the extracellular ligand binding uPAR to intracellular transducer(s).
-
Removal of domain D2 or D3 of the human Urokinase Receptor does not affect ligand affinity.
FEBS letters, 1996Co-Authors: Leena Riittinen, Paola Limongi, Massimo P. Crippa, Massimo Conese, Luciano Hernandez-marrero, Francesca Fazioli, Francesco BlasiAbstract:The main ligand-binding determinant of the human Urokinase Receptor (uPAR) is located in the amino terminal domain D1, but when isolated this domain presents a 1500 fold lower affinity than the intact three-domain uPAR (D1D2D3) [1]. uPAR mutants missing either domain 2 (D1HD3) or domain 3 (D1D2) were expressed in murine LB6 cells and showed to be properly GPI-anchored to the cell surface. Binding assays with [125I]ATF demonstrated that these mutants possessed a normal (D1D2) or slightly reduced (D1HD3) affinity, indicating that a high ligand-affinity may be achieved by a combination of D1 with domain D2 or D3.
Bernard Degryse - One of the best experts on this subject based on the ideXlab platform.
-
Data on the inhibition of cell proliferation and invasion by the D2A-Ala peptide derived from the Urokinase Receptor
'Elsevier BV', 2019Co-Authors: F. Furlan, Ralitsa Arnaudova, Giuseppina Andreotti, Valentina Citro, Maria Vittoria Cubellis, Andrea Motta, G. Eden, M. Archinti, Bernard DegryseAbstract:The data presented in this article are connected to our research article entitled \u201cD2A-Ala peptide derived from the Urokinase Receptor exerts anti-tumoural effects in vitro and in vivo\u201d (Furlan et al., 2018). These data further extend our understanding of the inhibitory effects of D2A-Ala peptide. Dose-response curve using a wide range of concentrations of D2A-Ala shows that this peptide has no effects per se on proliferation of rat smooth muscle cells (RSMC). However, D2A-Ala dose-dependently inhibits epidermal growth factor (EGF)-induced RSMC proliferation. Kinetics lasting up to seven days revealed that D2A-Ala peptide completely blocked EGF-promoted RSMC proliferation. Moreover, D2A-Ala peptide inhibited invasion of HT 1080 cells towards RSMC
-
Data on the inhibition of cell proliferation and invasion by the D2A-Ala peptide derived from the Urokinase Receptor
Elsevier, 2019Co-Authors: Federico Furlan, Gabriele Eden, Marco Archinti, Ralitsa Arnaudova, Giuseppina Andreotti, Valentina Citro, Maria Vittoria Cubellis, Andrea Motta, Bernard DegryseAbstract:The data presented in this article are connected to our research article entitled “D2A-Ala peptide derived from the Urokinase Receptor exerts anti-tumoural effects in vitro and in vivo” (Furlan et al., 2018). These data further extend our understanding of the inhibitory effects of D2A-Ala peptide. Dose-response curve using a wide range of concentrations of D2A-Ala shows that this peptide has no effects per se on proliferation of rat smooth muscle cells (RSMC). However, D2A-Ala dose-dependently inhibits epidermal growth factor (EGF)-induced RSMC proliferation. Kinetics lasting up to seven days revealed that D2A-Ala peptide completely blocked EGF-promoted RSMC proliferation. Moreover, D2A-Ala peptide inhibited invasion of HT 1080 cells towards RSMC. Keywords: Peptide, Urokinase Receptor, Cell proliferation, Cell invasio
-
D2A sequence of the Urokinase Receptor induces cell growth through αvβ3 integrin and EGFR
Cellular and Molecular Life Sciences, 2018Co-Authors: Gabriele Eden, Marco Archinti, Federico Furlan, Ralitsa Arnaudova, Giuseppina Andreotti, Valentina Citro, Maria Vittoria Cubellis, Andrea Motta, Bernard DegryseAbstract:The Urokinase Receptor (uPAR) stimulates cell proliferation by forming a macromolecular complex with αvβ3 integrin and the epidermal growth factor Receptor (EGFR, ErbB1 or HER1) that we name the uPAR proliferasome. uPAR transactivates EGFR, which in turn mediates uPAR-initiated mitogenic signal to the cell. EGFR activation and EGFR-dependent cell growth are blocked in the absence of uPAR expression or when uPAR activity is inhibited by antibodies against either uPAR or EGFR. The mitogenic sequence of uPAR corresponds to the D2A motif present in domain 2. NMR analysis revealed that D2A synthetic peptide has a particular three-dimensional structure, which is atypical for short peptides. D2A peptide is as effective as EGF in promoting EGFR phosphorylation and cell proliferation that were inhibited by AG1478, a specific inhibitor of the tyrosine kinase activity of EGFR. Both D2A and EGF failed to induce proliferation of NR6-EGFR-K721A cells expressing a kinase-defective mutant of EGFR. Moreover, D2A peptide and EGF phosphorylate ERK demonstrating the involvement of the MAP kinase signalling pathway. Altogether, this study reveals the importance of sequence D2A of uPAR, and the interdependence of uPAR and EGFR.
-
The Urokinase Receptor interactome.
Current pharmaceutical design, 2011Co-Authors: Gabriele Eden, Marco Archinti, Federico Furlan, Ronan P. Murphy, Bernard DegryseAbstract:The Urokinase Receptor (uPAR) was originally identified as the membrane Receptor of the serine protease Urokinase (uPA), thereby implicated in the plasminogen activation cascade and regulation of pericellular proteolysis. Later on, vitronectin was showed to be another major ligand providing uPAR with a role in cell adhesion. Other unrelated ligands have been subsequently reported including for example factor XII and SRPX2 expanding the functions of uPAR to unexpected biological areas such as the initiation of the coagulation cascade or the regulation of language development. Due to its glycosylphosphatidylinositol (GPI) anchor, uPAR has no intracellular domain and thus exerts its signaling capacity through lateral interactions with other components of the plasma membrane that actually mediate uPAR-induced signals. As yet, a total 42 proteins interacting directly with uPAR can be numbered comprising 9 soluble ligands and 33 lateral partners. The fact that uPAR interacts with members of three major families of membrane Receptors i.e. G protein-coupled Receptors, Receptor tyrosine kinases, and integrins implies that the actual number of components constituting the uPAR interacome is extremely high. For example, 156 factors belong to the integrin adhesome. Moreover, in the light of the wide diversity of the components of the uPAR interactome, uPAR appears to be an essential player of major biological systems including the blood coagulation, complement and plasma kallikrein-kinin cascades. This review describes the soluble ligands and lateral partners of the uPAR interactome, the mechanisms regulating uPAR interactions and their proved and/or potential biological functions.
-
The Urokinase Receptor system as strategic therapeutic target: challenges for the 21st century.
Current pharmaceutical design, 2011Co-Authors: Bernard DegryseAbstract:The story that led to the discovery of Urokinase Receptor (uPAR) system started in 1947 with the report of MacFarlane and Pilling who identified but did not named Urokinase (uPA). Today, the uPAR system is recognized as one very important actor in tumourigenesis and is even considered as a valuable tumour marker. Its critical functions justify the important effort of translational research that has produced many inhibitors which unfortunately failed to be transferred in the clinic. However, the role of the uPAR system in cancer development should not shade the vital functions of this system in hematopoietic stem cells mobilization, cognitive functions including language development, inflammation, innate immunity, coagulation and fibrinolysis. All these topics are covered in this special theme issue of the journal Current Pharmaceutical Design that comprises 9 reviews written by leading scientists. Other aspects are also embraced by additional articles including the first attempt to depict the complete atlas of the uPAR interactome, and the regulation of the uPAR system by the LDL Receptor-related protein-1 (LRP-1).
Harold A. Chapman - One of the best experts on this subject based on the ideXlab platform.
-
Random Peptide Bacteriophage Display as a Probe for Urokinase Receptor Ligands
Biological chemistry, 2002Co-Authors: Susan Fong, M. V. Doyle, Robert James Goodson, Harold A. Chapman, Robert J. Drummond, Jennifer R. Stratton, Lisa Mcguire, Laura V. Doyle, Steven RosenbergAbstract:The Urokinase Receptor is a multi-functional protein that plays a central role in cell surface plasminogen activation, cell migration, and cell adhesion. We previously demonstrated that high affinity peptide ligands for the Urokinase Receptor, which are Urokinase competitors, can be obtained from a 15mer peptide library (Goodson et al., 1994). In order to probe for additional Urokinase Receptor binding sites we affinity selected the same bacteriophage library on complexes of soluble Urokinase Receptor (suPAR) and the Receptor binding domain of Urokinase, residues 1-48 (uPA1-48). Bacteriophage were isolated which bound to suPAR and suPAR:uPA1-48 complexes with high yield. The peptide sequences encoded by these bacteriophage were distinct from those obtained previously on Urokinase Receptor expressing cells, and comprise two groups based upon effects on su-PAR:1-anilino-8-napthalene sulfonate (ANS) fluorescence, and vitronectin binding competition. Alanine scanning mutagensis of the soluble peptides was used to define minimal regions and key residues for suPAR binding by competition with the parent bacteriophage. A comparison of these results with sequences of domains of both vitronectin and integrin alpha-chains, which have been reported to be important for Urokinase Receptor binding, suggests that the homology with the peptide sequences selected is functionally significant.
-
Protease crosstalk with integrins: the Urokinase Receptor paradigm.
Thrombosis and haemostasis, 2001Co-Authors: Harold A. Chapman, Ying WeiAbstract:Migratory cells use both adhesion Receptors and proteolytic enzymes to regulate their interaction with and response to extracellular matrices. Cooperation between integrins and proteases operates at several levels: integrin signaling induces proteases, proteases co-localize with integrins, and proteases regulate the interface between integrins and the intracellular cytoskeleton. One protease system intimately connected to integrins is the Urokinase/Urokinase Receptor(uPAR)/plasmin system. Recent studies indicate Urokinase promotes the ligand-like binding of its Receptor to a set of b1 and b2 integrins, this binding in turn affecting integrin signaling and cell migration. The glycolipid anchor of uPAR associates with cholesterol-rich membrane rafts. Binding of uPAR to integrins may enrich integrin clusters with signaling molecules such as src-family kinases that localize to rafts and are important to integrin function. Signals derived from integrin/uPAR complexes promote the function of other integrins. Thus the Urokinase/plasmin system coordinates with integrins to regulate cell: matrix interactions.
-
Nonproteolytic Role for the Urokinase Receptor in Cellular Migration In Vivo
American journal of respiratory cell and molecular biology, 2000Co-Authors: David A Waltz, Steven Rosenberg, Ross M. Fujita, Xuiwei Yang, Lisa Natkin, Shaoqiu Zhuo, Craig Gerard, Harold A. ChapmanAbstract:The Urokinase Receptor (uPAR) binds and localizes Urokinase activity at cellular surfaces, facilitating fibrinolysis and cellular migration at sites of tissue injury. uPAR also participates in cellular signaling and regulates integrin-dependent adhesion and migration in vitro. We now report evidence that uPAR occupancy regulates cellular migration in vivo in the absence of functional Urokinase. Recombinant murine KC (1.5 μg), a potent neutrophil chemoattractant, was delivered to the lungs of wild-type, Urokinase-deficient or uPAR-deficient mice 18 h after intraperitoneal injection of 200 μg human immunoglobulin G (IgG) or a fusion protein composed of an amino-terminal Receptor-binding fragment of Urokinase and a human IgG Fc fragment (GFD-Fc). Whole lung lavage for recovery of leukocytes was performed 4 h later. KC treatment resulted in a 100-fold increase in lavage neutrophils. GFD-Fc injection resulted in > 50% reduction in neutrophil influx in both wild-type and Urokinase-deficient animals but had no e...
-
a role for caveolin and the Urokinase Receptor in integrin mediated adhesion and signaling
Journal of Cell Biology, 1999Co-Authors: Ying Wei, Xiuwei Yang, Qiumei Liu, John A Wilkins, Harold A. ChapmanAbstract:The assembly of signaling molecules surrounding the integrin family of adhesion Receptors remains poorly understood. Recently, the membrane protein caveolin was found in complexes with β1 integrins. Caveolin binds cholesterol and several signaling molecules potentially linked to integrin function, e.g., Src family kinases, although caveolin has not been directly implicated in integrin-dependent adhesion. Here we report that depletion of caveolin by antisense methodology in kidney 293 cells disrupts the association of Src kinases with β1 integrins resulting in loss of focal adhesion sites, ligand-induced focal adhesion kinase (FAK) phosphorylation, and adhesion. The nonintegrin Urokinase Receptor (uPAR) associates with and stabilizes β1 integrin/caveolin complexes. Depletion of caveolin in uPAR-expressing 293 cells also disrupts uPAR/integrin complexes and uPAR-dependent adhesion. Further, β1 integrin/caveolin complexes could be disassociated by uPAR-binding peptides in both uPAR-transfected 293 cells and human vascular smooth muscle cells. Disruption of complexes by peptides in intact smooth muscle cells blocks the association of Src family kinases with β1 integrins and markedly impairs their migration on fibronectin. We conclude that ligand-induced signaling necessary for normal β1 integrin function requires caveolin and is regulated by uPAR. Caveolin and uPAR may operate within adhesion sites to organize kinase-rich lipid domains in proximity to integrins, promoting efficient signal transduction.
-
identification of the Urokinase Receptor as an adhesion Receptor for vitronectin
Journal of Biological Chemistry, 1994Co-Authors: Robert J. Drummond, Steven Rosenberg, Harold A. ChapmanAbstract:Abstract Urokinase Receptors, expressed on surfaces of many cell types, focus to the pericellular space plasminogen-dependent proteolysis important in matrix remodeling and cell movement. We now report that the Urokinase Receptor (uPAR) is also a high affinity (Kd < 30 nM) Receptor for vitronectin. Recombinant uPAR binds vitronectin in the absence of Urokinase, but vitronectin binding is promoted by concurrent Receptor binding of either Urokinase or fragments thereof containing its uPAR binding domain. Stable epithelial cell transfectants expressing membrane-anchored uPAR, but not cells expressing soluble uPAR, become strongly adhesive with altered morphology in the absence of Urokinase. These observations identify a new class of vitronectin Receptor and imply a duality in function for the Receptor that intrinsically links matrix adhesion to regulation of protease activity. Increases in Urokinase Receptor expression known to be associated with cellular activation and malignant transformation could modulate cellular trafficking and function by promoting attachment to vitronectin.
R W Stephens - One of the best experts on this subject based on the ideXlab platform.
-
Soluble Urokinase Receptor released from human carcinoma cells: A plasma parameter for xenograft tumour studies
British Journal of Cancer, 1999Co-Authors: C Holst-hansen, M J A G Hamers, B E Johannessen, N Brünner, R W StephensAbstract:The Urokinase plasminogen activator Receptor (uPAR) plays a critical role in Urokinase-mediated plasminogen activation and thereby in the process leading to invasion and metastasis. Soluble Urokinase Receptor (suPAR) is released from tumours, and in cancer patients the blood level of soluble Receptor is increased. Using an enzyme-linked, immunosorbent assay (ELISA)-specific for the human Urokinase Receptor, release of soluble Receptor was measured in cultures of human breast carcinoma cells, in tumour extracts and in plasma from mice with xenografted human tumours. Soluble human Urokinase Receptor (shuPAR) was released into culture supernatant during the growth of the human breast cancer cell line MDA-MB-231 BAG, and the level of shuPAR in conditioned medium determined by ELISA was a linear function of both viable cell number and time of incubation. Western blotting showed that the form of shuPAR measured by ELISA in conditioned medium consisted virtually exclusively of the three-domain full-length protein, while uPAR in cell lysates consisted of full-length uPAR as well as the domains (2+3) cleavage product. shuPAR was also released into the plasma of nude mice during growth of MDA-MB-231 BAG, MDA-MB-435 BAG and HCT 116 cells as subcutaneously xenografted tumours. Western blotting demonstrated that the shuPAR released from the xenografted human tumours into plasma consisted of the three-domain full-length protein, despite the finding of some cleaved uPAR in detergent extracts of tumour tissue. The levels of shuPAR determined by ELISA in the plasma of host mice during the growth of xenografted cell lines were highly correlated with tumour volume.
-
Soluble Urokinase Receptor released from human carcinoma cells: a plasma parameter for xenograft tumour studies.
British journal of cancer, 1999Co-Authors: C Holst-hansen, M J A G Hamers, B E Johannessen, N Brünner, R W StephensAbstract:The Urokinase plasminogen activator Receptor (uPAR) plays a critical role in Urokinase-mediated plasminogen activation and thereby in the process leading to invasion and metastasis. Soluble Urokinase Receptor (suPAR) is released from tumours, and in cancer patients the blood level of soluble Receptor is increased. Using an enzyme-linked, immunosorbent assay (ELISA)-specific for the human Urokinase Receptor, release of soluble Receptor was measured in cultures of human breast carcinoma cells, in tumour extracts and in plasma from mice with xenografted human tumours. Soluble human Urokinase Receptor (shuPAR) was released into culture supernatant during the growth of the human breast cancer cell line MDA-MB-231 BAG, and the level of shuPAR in conditioned medium determined by ELISA was a linear function of both viable cell number and time of incubation. Western blotting showed that the form of shuPAR measured by ELISA in conditioned medium consisted virtually exclusively of the three-domain full-length protein, while uPAR in cell lysates consisted of full-length uPAR as well as the domains (2+3) cleavage product. shuPAR was also released into the plasma of nude mice during growth of MDA-MB-231 BAG, MDA-MB-435 BAG and HCT 116 cells as subcutaneously xenografted tumours. Western blotting demonstrated that the shuPAR released from the xenografted human tumours into plasma consisted of the three-domain full-length protein, despite the finding of some cleaved uPAR in detergent extracts of tumour tissue. The levels of shuPAR determined by ELISA in the plasma of host mice during the growth of xenografted cell lines were highly correlated with tumour volume. © 1999 Cancer Research Campaign
-
ELISA determination of soluble Urokinase Receptor in blood from healthy donors and cancer patients
Clinical chemistry, 1997Co-Authors: R W Stephens, Keld Dano, M J A G Hamers, Anders N. Pedersen, Hans Jørgen Nielsen, Gunilla Høyer-hansen, E Rønne, E. Dybkjær, N BrünnerAbstract:Measurement of Urokinase Receptor (uPAR) in tumor extracts has prognostic value, but assay of the soluble uPAR (suPAR) in peripheral blood may offer wider applications in cancer patient management. A tumor extract uPAR ELISA was modified to eliminate nonspecific plasma protein interference, enabling specific detection of suPAR in plasma and sera with >90% recovery of added calibrator. suPAR concentrations in citrate plasma correlated with sera in 93 healthy blood donors ( r = 0.84, P
Steven Rosenberg - One of the best experts on this subject based on the ideXlab platform.
-
Random Peptide Bacteriophage Display as a Probe for Urokinase Receptor Ligands
Biological chemistry, 2002Co-Authors: Susan Fong, M. V. Doyle, Robert James Goodson, Harold A. Chapman, Robert J. Drummond, Jennifer R. Stratton, Lisa Mcguire, Laura V. Doyle, Steven RosenbergAbstract:The Urokinase Receptor is a multi-functional protein that plays a central role in cell surface plasminogen activation, cell migration, and cell adhesion. We previously demonstrated that high affinity peptide ligands for the Urokinase Receptor, which are Urokinase competitors, can be obtained from a 15mer peptide library (Goodson et al., 1994). In order to probe for additional Urokinase Receptor binding sites we affinity selected the same bacteriophage library on complexes of soluble Urokinase Receptor (suPAR) and the Receptor binding domain of Urokinase, residues 1-48 (uPA1-48). Bacteriophage were isolated which bound to suPAR and suPAR:uPA1-48 complexes with high yield. The peptide sequences encoded by these bacteriophage were distinct from those obtained previously on Urokinase Receptor expressing cells, and comprise two groups based upon effects on su-PAR:1-anilino-8-napthalene sulfonate (ANS) fluorescence, and vitronectin binding competition. Alanine scanning mutagensis of the soluble peptides was used to define minimal regions and key residues for suPAR binding by competition with the parent bacteriophage. A comparison of these results with sequences of domains of both vitronectin and integrin alpha-chains, which have been reported to be important for Urokinase Receptor binding, suggests that the homology with the peptide sequences selected is functionally significant.
-
Nonproteolytic Role for the Urokinase Receptor in Cellular Migration In Vivo
American journal of respiratory cell and molecular biology, 2000Co-Authors: David A Waltz, Steven Rosenberg, Ross M. Fujita, Xuiwei Yang, Lisa Natkin, Shaoqiu Zhuo, Craig Gerard, Harold A. ChapmanAbstract:The Urokinase Receptor (uPAR) binds and localizes Urokinase activity at cellular surfaces, facilitating fibrinolysis and cellular migration at sites of tissue injury. uPAR also participates in cellular signaling and regulates integrin-dependent adhesion and migration in vitro. We now report evidence that uPAR occupancy regulates cellular migration in vivo in the absence of functional Urokinase. Recombinant murine KC (1.5 μg), a potent neutrophil chemoattractant, was delivered to the lungs of wild-type, Urokinase-deficient or uPAR-deficient mice 18 h after intraperitoneal injection of 200 μg human immunoglobulin G (IgG) or a fusion protein composed of an amino-terminal Receptor-binding fragment of Urokinase and a human IgG Fc fragment (GFD-Fc). Whole lung lavage for recovery of leukocytes was performed 4 h later. KC treatment resulted in a 100-fold increase in lavage neutrophils. GFD-Fc injection resulted in > 50% reduction in neutrophil influx in both wild-type and Urokinase-deficient animals but had no e...
-
Urokinase Receptor Antagonists Inhibit Angiogenesis and Primary Tumor Growth in Syngeneic Mice
Cancer research, 1996Co-Authors: Hye Yeong Min, Laura V. Doyle, Charles R. Vitt, Catherine L. Zandonella, Jennifer R. Stratton-thomas, Marc A. Shuman, Steven RosenbergAbstract:Urokinase plasminogen activator (uPA) and its Receptor are key components of a cell surface proteolytic cascade used by tumor cells and capillary endothelial cells for basement membrane invasion, a process required for metastasis and angiogenesis. We have cloned, expressed, and purified the epidermal growth factor-like domain of murine uPA alone and fused it to the Fc portion of human IgG as high-affinity murine Urokinase Receptor antagonists. These molecules are potent inhibitors of murine Urokinase binding to its Receptor and inhibit angiogenesis in an in vitro model of capillary tube formation in fibrin gels. In vivo, basic fibroblast growth factor-induced neovascularization and B16 melanoma growth in syngeneic mice are also substantially suppressed by these molecules. Coupled with previous studies showing inhibition of metastasis, these findings suggest that Urokinase Receptor antagonists may be useful therapeutically as inhibitors of tumor progression.
-
identification of the Urokinase Receptor as an adhesion Receptor for vitronectin
Journal of Biological Chemistry, 1994Co-Authors: Robert J. Drummond, Steven Rosenberg, Harold A. ChapmanAbstract:Abstract Urokinase Receptors, expressed on surfaces of many cell types, focus to the pericellular space plasminogen-dependent proteolysis important in matrix remodeling and cell movement. We now report that the Urokinase Receptor (uPAR) is also a high affinity (Kd < 30 nM) Receptor for vitronectin. Recombinant uPAR binds vitronectin in the absence of Urokinase, but vitronectin binding is promoted by concurrent Receptor binding of either Urokinase or fragments thereof containing its uPAR binding domain. Stable epithelial cell transfectants expressing membrane-anchored uPAR, but not cells expressing soluble uPAR, become strongly adhesive with altered morphology in the absence of Urokinase. These observations identify a new class of vitronectin Receptor and imply a duality in function for the Receptor that intrinsically links matrix adhesion to regulation of protease activity. Increases in Urokinase Receptor expression known to be associated with cellular activation and malignant transformation could modulate cellular trafficking and function by promoting attachment to vitronectin.