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)

Fibrin is a temporary matrix which not only covers a wound, but also provides a structure for invading cells during healing. Changes in the polymerization conditions before gelation of the clot affect the structure of fibrin and thus might influence the interaction with invading cells. Therefore we tested whether changes in the fibrin structure influence the formation of capillary-like tubular structures by human microvascular endothelial cells (hMVEC) in an in vitro angiogenesis model. Opaque [125I]fibrin structures prepared at pH 7.0, fibrin matrices at pH 7.4 and transparent [125I]fibrin structures prepared at pH 7.8 were neutralized (pH 7.4) before seeding hMVEC on top of them in confluent density. Endothelial cells were stimulated with a growth factor [basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF)165] and a cytokine [tumor necrosis factor (TNF)-alpha] to induce the u-PA/u-PA receptor-dependent formation of capillary-like tubular structures. The formation of these structures was quantified by determining the length of the invasive structures by image analysis and by measuring the accompanying [125I]fibrin degradation. Ingrowth of tubular structures proceeded at a faster rate in opaque matrices consisting of thick fibrin fibers as compared to transparent gels with fine fibrin fibers. The more rapid ingrowth of tubular structures in opaque fibrin gels induced by bFGF/TNF-alpha or VEGF165/TNF-alpha was accompanied by a larger extent of fibrin degradation. Both processes were inhibited by aprotinin and epsilon-aminocaproic acid indicating the involvement of plasmin. They were also inhibited by anti-u-PA or anti-u-PA receptor IgG, but not by anti-t-PA IgG, suggesting the involvement of cell-bound u-PA activity. However, in the opaque fibrin gels, the tubular structures dissolved upon prolonged incubation due to excessive fibrin degradation. Simulation of hMVEC with bFGF alone did not induce tubular structures, but ca used a high degree of t-PA- and plasmin-dependent fibrin lysis, and, after several days, a partial detachment of sheets of cells. Gradual inhibition of the excessive fibrin degradation by a series of aprotinin concentrations did not lead to tube formation in bFGF-treated cells. These data indicate that the formation and stability of tubular structures by hMVEC in fibrin is accompanied by controlled fibrinolysis and depends critically not only on cell-bound u-PA-dependent plasminogen activation, but also on the fibrin structure. Because the fibrin structure is largely influenced by the conditions in which fibrin has been polymerized, these conditions may have considerable impact on angiogenesis during wound healing and vascularization of tumour stroma.
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PMID:Influence of fibrin structure on the formation and maintenance of capillary-like tubules by human microvascular endothelial cells. 1451 71

Infection with Helicobacter pylori (H. pylori) is considered a risk factor for gastric carcinoma. The purpose of this study was to clarify whether H. pylori infection plays a role in progression of gastric carcinoma. We examined the expression of genes encoding angiogenic factors and proteases by human gastric carcinoma cell lines (MKN-1 and TMK-1) co-cultured with or without H. pylori by cDNA microarray analysis. Co-culture with H. pylori increased expression of mRNAs encoding interleukin (IL)-8, vascular endothelial growth factor (VEGF), angiogenin, urokinase-type plasminogen activator (uPA), and metalloproteinase (MMP)-9 by gastric carcinoma cells. Up-regulation of these genes at the mRNA and protein levels was confirmed by Northern blot analysis, semi-quantitative RT-PCR analysis, and ELISA. In vitro angiogenic and collagenase activities of conditioned medium from the gastric carcinoma cells were also stimulated by co-culture with H. pylori. These results indicate that H. pylori infection may regulate angiogenesis and invasion of human gastric carcinoma.
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PMID:Helicobacter pylori infection influences expression of genes related to angiogenesis and invasion in human gastric carcinoma cells. 1462 53

VEGF-A is a major angiogenesis and permeability factor. Its cellular effects, which can be used as targets in anti-angiogenesis therapy, have mainly been studied in vitro using endothelial cell cultures. The purpose of the present study was to further characterize these effects in vivo in vascular endothelial cells and pericytes, in an experimental monkey model of VEGF-A-induced iris neovascularization. Two cynomolgus monkeys (Macaca fascicularis) received four injections of 0.5 microg VEGF-A in the vitreous of one eye and PBS in the other eye. After sacrifice at day 9, eyes were enucleated and iris samples were snap-frozen for immunohistochemistry (IHC) and stained with a panel of antibodies recognizing endothelial and pericyte determinants related to angiogenesis and permeability. After VEGF-A treatment, the pre-existing iris vasculature showed increased permeability, hypertrophy, and activation, as demonstrated by increased staining of CD31, PAL-E, tPA, uPA, uPAR, Glut-1, and alphavbeta3 and alphavbeta5 integrins, VEGF receptors VEGFR-1, -2 and -3, and Tie-2 in endothelial cells, and of NG2 proteoglycan, uPA, uPAR, integrins and VEGFR-1 in pericytes. Vascular sprouts at the anterior surface of the iris were positive for the same antigens except for tPA, Glut-1, and Tie-2, which were notably absent. Moreover, in these sprouts VEGFR-2 and VEGFR-3 expression was very high in endothelial cells, whereas many pericytes were present that were positive for PDGFR-beta, VEGFR-1, and NG2 proteoglycan and negative for alpha-SMA. In conclusion, proteins that play a role in angiogenesis are upregulated in both pre-existing and newly formed iris vasculature after treatment with VEGF-A. VEGF-A induces hypertrophy and loss of barrier function in pre-existing vessels, and induces angiogenic sprouting, characterized by marked expression of VEGFR-3 and lack of expression of tPA and Tie-2 in endothelial cells, and lack of alpha-SMA in pericytes. Our in vivo study indicates a role for alpha-SMA-negative pericytes in early stages of angiogenesis. Therefore, our findings shed new light on the temporal and spatial role of several proteins in the angiogenic cascade in vivo.
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PMID:In vivo angiogenic phenotype of endothelial cells and pericytes induced by vascular endothelial growth factor-A. 1468 16

The lipid growth factor lysophosphatidic acid (LPA) is produced by ovarian cancer cells in quantities sufficient to attain concentrations of up to 10 microM. An autocrine circuit was demonstrated when ovarian cancer cells, but not normal ovarian surface epithelial cells, were proven to express LPA(2) (Edg-4) and LPA(3) (Edg-7) G protein-coupled receptors for LPA. Human LPA(2) now has been expressed transgenically in C57BL/6 mouse ovaries under direction of the alpha-inhibin large promoter. Human LPA(2) mRNA and protein were detected in all transgenic (TG) mouse ovaries at levels far higher than in other tissues and at least fivefold higher than in cultured lines of human ovarian cancer cells, with the expected sex cord-stromal distribution. Most LPA(2) TG ovaries produced significantly higher levels than non-TG ovaries of type A, but not type B, vascular endothelial growth factor (VEGF), isomers of VEGF-A, and urokinase-type plasminogen activator (uPA). Many LPA(2) TG ovaries had elevated expression of VEGF receptors 1 and 2, and a depressed level of type 2 PA inhibitor. Thus, the LPA-LPA(2) circuit regulates ovarian cells both directly and through increases in protein growth factor systems.
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PMID:Induction of protein growth factor systems in the ovaries of transgenic mice overexpressing human type 2 lysophosphatidic acid G protein-coupled receptor (LPA2). 1471 17

Cells that have acquired a proliferative advantage form islets of hyperplasia during the initial stages of tumor development. Like normal cells, they require oxygen and nutrients to survive and proliferate. The centre of the islets is characterized by low oxygen pressure and low pH, conditions that stimulate the sprouting of new capillaries from nearby vascular beds. It is now well established that neovascularisation (angiogenesis) of the hyperplasias is essential for further development of the tumor. The family of ras oncogenes promotes the initiation of tumor growth by stimulating tumor cell proliferation, but also ensures tumor progression by stimulating tumor-associated angiogenesis. Oncogenic Ras proteins stimulate a number of effector pathways that culminate in the transcriptional activation of genes that control angiogenesis. Moreover, Ras signaling leads to stabilization of the produced mRNAs and, possibly, to enhanced initiation of their translation. In this review we describe the mechanisms that underlie Ras regulation of vascular endothelial growth factor (VEGF), cyclooxygenases (COX-1/-2), thrombospondins (TSP-1/-2), urokinase plasminogen activator (uPA) and matrix metalloproteases-2 and -9 (MMP-2/-9). As a result of these Ras-regulated changes in gene expression, the tumor cells cause stimulation of endothelial cells in nearby vascular beds (directly via VEGF, and indirectly via COX-produced prostaglandins) and promote remodeling of the extracellular matrix (by lowering TSP and increasing uPA/MMPs). The latter effect makes growth factors available for endothelial cell activation and migration. In addition, tumor cell-activated stromal cells also contribute to the stimulation of angiogenesis by further enhancing the production and secretion of pro-angiogenic factors into the tumor stroma.
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PMID:Stimulation of angiogenesis by Ras proteins. 1498 65

Trophoblast invasion, accompanied by degradation of extracellular matrix, is crucial to normal pregnancy development, whereas shallow placental invasion and implantation likely plays a role in the subsequent development of pre-eclampsia. The growth factors vascular endothelial growth factor (VEGF), epidermal growth factor (EGF) and fibroblast growth factor (FGF) are placental growth factors that activate degradation of extracellular matrix. We determined the effect of VEGF, EGF, FGF-2, FGF-4 and FGF-10 on the plasminogen activator system of first trimester cytotrophoblasts cultured in vitro. We studied the activity of urokinase plasminogen activator (uPA), its inhibitor plasminogen activator inhibitor-1 (PAI-1), and 92 kDa gelatinase-B (matrix metalloproteinase-9, MMP-9), using protein gel and reversed gel zymography. The expression pattern of FGF-4 and FGF-10 in human placental sections was determined by immunohistochemistry. FGF-4 was expressed in first trimester villi stroma, primarily in endothelial cells. FGF-10 expression was localized to first trimester extravillous trophoblasts. VEGF, EGF, FGF-4 and FGF-10, but not FGF-2, stimulate the activity of trophoblast uPA, PAI-1 and MMP-9. These results support the hypothesis that specific growth factors modulate the invasive potential of trophoblasts, and therefore may play an important role in early placental development. Our findings may contribute to the understanding of the pathophysiology of diseases associated with shallow placentation, such as pre-eclampsia.
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PMID:Vascular endothelial growth factor, epidermal growth factor and fibroblast growth factor-4 and -10 stimulate trophoblast plasminogen activator system and metalloproteinase-9. 1499 96

Capitalizing on a proven multicistronic expression vector platform we have designed novel pTRIDENT vectors which (1). enable coordinated expression of three desired transgenes, (2). are size-optimized, (3). take advantage of small highly efficient internal ribosome entry sites of the GTX or Rbm3 type, (4). harbor various sites specific for homing endonucleases facilitating promoter/multicistronic expression unit/polyadenylation site swapping as well as (5). straightforward integration into human HIV-l-based lentiviral expression vectors tailored to contain compatible homing endonucleases. Multicistronic expression profiles of novel pTRIDENT vectors engineered for different tricistronic expression configurations encoding human low-molecular-weight urokinase-type plasminogen activator (u-PA(LMW)) or Bacillus stearothermophilus-derived alpha-amylase (SAMY), human vascular endothelial growth factor (hVEGF), and human placental secreted alkaline phosphatase (SEAP) have been quantified in Chinese hamster ovary cells (CHO-K1), mouse fibroblasts (NIH/3T3), and/or human fibrosarcoma (HT-1080) cells. In addition, a pTRIDENT-derived SAMY-VEGF-SEAP expression cassette transferred into a compatible lentiviral expression vector enabled simultaneous high-level transgene expression following transduction of transgenic lentiviral particles into primary human chondrocytes.
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PMID:New-generation multicistronic expression platform: pTRIDENT vectors containing size-optimized IRES elements enable homing endonuclease-based cistron swapping into lentiviral expression vectors. 1505 37

The angiogenic response of endothelial cells initiated by different growth factors is accompanied by assembly of cell surface-bound proteolytic machinery as a prerequisite for focal invasion. We have shown previously how the vascular endothelial growth factor (VEGF) initiates proteolysis by activation of pro-urokinase (pro-PA) via the VEGF receptor-2 (VEGFR-2). We now show that the cell surface receptor of the uPA-system, the urokinase receptor (uPAR), is redistributed to focal adhesions at the leading edge of endothelial cells in response to VEGF. VEGF165 and VEGF-E, both interacting with VEGFR-2, but not PlGF exclusively stimulating VEGFR-1, induce within minutes internalization of uPAR via an LDL receptor-like molecule, dependent on generation of active uPA and the presence of plasminogen activator inhibitor-1 (PAI-1). uPAR seems to play a pivotal role in VEGFR-2-induced endothelial cell migration because cleavage of surface uPAR impaired the migratory response of endothelial cells toward VEGF-E, but not toward PlGF.
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PMID:Vascular endothelial growth factor receptor-2-induced initial endothelial cell migration depends on the presence of the urokinase receptor. 1513 Oct 9

Intervertebral disc herniation (HD) is one of the most common orthopaedic conditions. MRI analysis of HD has revealed a spontaneous resorption mechanism related with neo-vascularization. It appears that the interaction of activated macrophages with disc tissues leads to the generation of inflammatory cytokines. Moreover, inflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha) is required for the induction of angiogenesis inducing factors such as vascular endothelial growth factor (VEGF) or matrix degrading enzymes such as MMP-3, MMP-7 and plasmin. We hypothesized that these molecules play a crucial role during spontaneous HD resorption. In this study, we have examined the sequential expression of these molecules using a co-culture system which is composed of the interaction of activated macrophages and disc tissues as a model of the acute response of inflammation occurred in HD. We have also considered the mechanism of activating latent MMPs during HD resorption process. Current our results indicate that upregulation of both TNF-alpha mRNA and protein expressions occur first in the inflammation induced by HD. VEGF upregulation follows the increased level of TNF-alpha expression. Both plasmin and MMP-3 are upregulated at later time points. We also demonstrate that both TNF-alpha and VEGF induce upregulated expression of urokinase-type plasminogen activator (u-PA). Our previous work has demonstrated that TNF-alpha could upregulate the expression of VEGF, MMP-3 and MMP-7 in the co-culture system. It has been reported that plasmin could affect to activate latent MMPs. Based on these findings, we suggest that TNF-alpha acts as the initiator of inflammation following contact between macrophages and disc chondrocytes and that plasmin and u-PA play a crucial role in activation of MMPs. We propose a spontaneous HD resorption cascade. Further understanding of the resorption process may provide future novel therapies for HD.
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PMID:Sequential dynamics of inflammatory cytokine, angiogenesis inducing factor and matrix degrading enzymes during spontaneous resorption of the herniated disc. 1518 52

To study the molecular mechanism of inhibition of angiogenesis in HER-2/neu-overexpressing breast cancer by genistein, HER-2/neu negative expression breast cancer MCF-7 cells were transfected with HER-2/neu to establish HER-2/neu-overexpressing MCF-7 cells (named MCF-7/HER-2). Expression of vascular endothelial growth factor (VEGF), urokinase-type plasminogen activator (uPA), matrix metalloproteinase-2,9 (MMP-2,9) in MCF-7, MCF-7/HER-2 as well as genistein-treated MCF-7/HER-2 were measured by immunocytochemistry and Western blot. We found that the expression of VEGF, MMP-2,9 and uPA in MCF-7/HER-2 cells were highter than that in MCF-7 cells, those angiogenesis related factors expression in MCF-7/HER-2 cells significantly decreased after treatment with genistein. Genistein could inhibit expression of angiogenesis-related factors VEGF, MMP-2,9 and uPA in HER-2/neu-overexpressing breast cancer cells, and this may be part of molecular mechanism of its anti-angiogenesis in HER-2/neu-overexpressing breast cancer.
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PMID:[Effect of genistein on expression of angiogenesis related factors in HER-2/neu-overexpressing breast cancer cells]. 1532 30


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