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

The urokinase-type plasminogen activator plays a central role in tissue remodeling by controlling the synthesis of the extracellular matrix-degrading plasmin. Urokinase expression is transcriptionally regulated by a variety of cytokines including TNF-alpha. The present study was undertaken to identify key transcription factor binding sites in the urokinase promoter necessary for the TNF-alpha-dependent induction of urokinase expression. TNF-alpha treatment of a squamous cell carcinoma cell line, UM-SCC-1, which produces no detectable TNF-alpha, led to a dose-dependent increase in urokinase secretion, thus reflecting a more abundant mRNA. Transient transfections of UM-SCC-1 cells with a CAT reporter driven by 5' deletion fragments of the urokinase promoter indicated that a sequence spanning -2109 to -1870, which contained binding sites for AP-1 and PEA3 was required for the stimulation by TNF-alpha. Mutation of an AP-1 binding site at -1967 and a PEA3 motif at -1973 completely abrogated the inductive effect of TNF-alpha on urokinase promoter activity. Mobility shift assays indicated the presence of a jun-containing factor(s) which bound specifically to the AP-1 sequence present in the urokinase promoter. The amount and/or activity of this factor(s) was greatly enhanced by TNF-alpha treatment. UM-SCC-1 cells transiently transfected with a CAT reporter driven by 3 tandem AP-1 binding sites demonstrated increased CAT activity following TNF-alpha treatment. Thus, the induction of urokinase expression by TNF-alpha is likely to involve the altered expression and/or activity of transcription factors which bind to the AP-1 and PEA3 target sequences in the urokinase promoter.
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PMID:Stimulation of urokinase expression by TNF-alpha requires the activation of binding sites for the AP-1 and PEA3 transcription factors. 762 64

The present study was undertaken to determine the role of the metalloproteinase MMP-9 in the invasive phenotype of squamous-cell carcinoma of the oral cavity and the regulation of its expression. Zymographic analysis of conditioned medium from 2 highly invasive squamous-cell-carcinoma cell lines indicated large amounts of an enzyme which was indistinguishable, in size (92 kDa) from the MMP-9 pro-enzyme. Conversion of the 92-kDa gelatinase into a lower-molecular-weight species (84 kDa), identical in size to the activated gelatinase, was evident when both cell lines, which are avid secretors of urokinase, were cultured in the presence of plasminogen. Penetration of an extracellular-matrix-coated filter was dramatically reduced in the presence of the collagenase inhibitor, tissue inhibitor of metalloproteinase-2, suggesting a critical role for MMP-9 in the invasive process. Immunohistochemical studies demonstrating the presence of MMP-9 in tumor cells of resected squamous-cell cancers suggested that secretion of this collagenase by cells in vitro was reflective of the in vivo setting. Since several phorbol-ester response elements are present in the MMP-9 promoter, we determined the role of protein-kinase-C pathways in the regulation of MMP-9 expression in cultured SCC. Treatment of cells with PMA resulted in a more-than-20-fold increase in the level of protein and mRNA. Conversely, culturing of cells in the presence of the protein-kinase-C inhibitor, calphostin-C, led to a dose-dependent decrease in the amount of MMP-9 mRNA and protein, suggesting that the constitutive expression of this collagenase reflects activation of this signal transduction pathway. In summary, our data suggest that, for a sub-population of squamous-cell carcinomas, secreted MMP-9 is an important determinant of the invasive phenotype, and that the expression of this metalloproteinase is regulated by protein-kinase-C pathways.
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PMID:Role and regulation of expression of 92-kDa type-IV collagenase (MMP-9) in 2 invasive squamous-cell-carcinoma cell lines of the oral cavity. 768 50

The plasminogen activator (PA)/plasmin system is thought to be involved in processes such as tumor invasion and wound healing, during which epithelial and mesenchymal cells come close together. However, information on regulation of the PA/plasmin system during epithelial-mesenchymal interactions is scarce. Therefore, we examined the in vitro modulation of the production and activity of the components of the PA/plasmin system in squamous carcinoma cells (SCC-4) and normal human keratinocytes in relation to cell density and the presence or absence of fibroblasts (3T3 cells). There was an inverse relation between cell density and mRNA expression for urokinase-type plasminogen activator (u-PA) and u-PA receptor in both SCC-4 cells and keratinocytes. In addition, such a relation was found for plasminogen activator inhibitor types 1 (PAI-1) and 2 (PAI-2) in SCC-4 monocultures, but not in keratinocyte monocultures. In contrast to monocultures, variation of cell density did not affect the mRNA expression of the components of the PA/plasmin system in cocultures of SCC-4 cells or keratinocytes with 3T3 cells. However, the relative expression of mRNAs in co-cultures was clearly different from that in monocultures, especially at low cell density. For most of the components of the PA/plasmin system, a decrease in mRNA expression and u-PA receptor protein was observed at most cell densities, whereas for PAI-1 only in keratinocytes a marked increase was documented. Zymography of supernatants revealed that the levels of both free u-PA and PA-PAI were increased in SCC-4/3T3 co-cultures, whereas in keratinocytes/3T3 co-cultures, only levels of the PA-PAI complex were increased, while the amount of free u-PA activity decreased. This occurred despite the increase u-PA immunoreactivity and was probably caused by the markedly elevated levels of immunoreactive PAI-1. The results of the present study reveal that the production and synthesis of various components of the PA/plasmin system in keratinocytes and SCC-4 cells depend on the density of epithelial cells and are modulated by fibroblasts, probably through a direct cell-cell or cell-matrix contact. Fibroblast-induced modulations are similar in keratinocytes and SCC-4 cells except for the regulation of PAI-1, which is markedly enhanced only in keratinocytes. This suggests that the modulation of PA activity in the direct microenvironment may be different under physiologic and pathologic conditions.
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PMID:Differential regulation of plasminogen activation in normal keratinocytes and SCC-4 cells by fibroblasts. 786 Oct 5

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), a suspected human carcinogen, is believed to produce its toxic and carcinogenic effects by altering expression of growth-regulatory factors. TCDD alters the expression of a number of specific genes in the transformed human keratinocyte cell line, SCC-12F, including transforming growth factor-alpha (TGF-alpha), TGF-beta 2, plasminogen activator inhibitor-2 (PAI-2), and interleukin-1 beta (IL-1 beta). To determine whether nontransformed human keratinocytes (NHK) respond similarly to TCDD, we studied the effect of TCDD on NHK growth and differentiation, and gene expression. NHK were treated prior to reaching confluence with 10 nM TCDD and evaluated at 1, 2, 3, and 5 days following treatment for the effect of TCDD on cell number, morphology, involucrin levels, mRNA expression, and protein concentrations. TCDD altered both the mRNA and protein concentrations of TGF-alpha, TGF-beta 2, PAI-2, and IL-1 beta. The mRNA level for u-PA, a plasminogen activator that is inhibited by PAI-2, was not altered following TCDD treatment. However, u-PA protein levels were significantly induced, indicating an effect of TCDD on u-PA synthesis, secretion, or turnover. TCDD enhanced NHK differentiation, as determined by an increase in involucrin expression. TCDD did not alter cell number or colony-forming efficiency, suggesting that TCDD was enhancing the differentiation of cells already committed to terminal differentiation. These results demonstrate that treatment of NHK with TCDD results in the simultaneous modulation of expression of a number of growth-regulatory proteins and suggest that the growth and differentiation response of human keratinocytes to TCDD is due to a complex interaction of these diverse proteins.
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PMID:Regulation of gene expression and acceleration of differentiation in human keratinocytes by 2,3,7,8-tetrachlorodibenzo-p-dioxin. 804 63

The urokinase-type plasminogen activator contributes to tissue remodeling by controlling the synthesis of the extracellular matrix-degrading plasmin. We undertook a study to determine the role of the extracellular signal-regulated kinases (ERKs) in the regulation of urokinase-type plasminogen activator expression in a squamous cell carcinoma cell line (UM-SCC-1) that contains a transcriptionally activated urokinase-type plasminogen activator gene. Transient transfection studies using a CAT reporter driven by the urokinase-type plasminogen activator promoter, which had progressive 5' deletions or which had been point-mutated, indicated the requirement of binding sites for AP-1 (-1967) and PEA3 (-1973) for its maximal activation. Expression of a mutant jun protein, which lacks the transactivation domain, caused a dose-dependent repression of a CAT reporter driven by either the urokinase-type plasminogen activator promoter or three tandem AP-1 repeats upstream of a thymidine kinase minimal promoter indicating the importance of AP-1-binding transcription factor(s) in the regulation of urokinase-type plasminogen activator synthesis. Mobility shift assays with UM-SCC-1 nuclear extract revealed binding of fos and junD proteins to an oligonucleotide spanning the AP-1 site at -1967. In-gel kinase assays indicated the constitutive activation of ERK1, which regulates fos synthesis via phosphorylation of p62TCF, but not ERK2, in UM-SCC-1 cells. Moreover, the expression of a dominant-negative ERK1, but not ERK2, repressed urokinase-type plasminogen activator promoter activity. Similarly, interfering with the function of the c-raf serine-threonine kinase, which lies upstream of ERK1, by the expression of a kinase-inactive c-raf repressed the activity of a CAT reporter driven by either the urokinase-type plasminogen activator promotor or tandem AP-1 repeats. These data suggest that urokinase-type plasminogen activator expression in UM-SCC-1 cells is regulated partly by an ERK1, but not ERK2, -dependent signaling pathway.
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PMID:Regulation of urokinase-type plasminogen activator expression by an ERK1-dependent signaling pathway in a squamous cell carcinoma cell line. 876 47

The elevated expression of the urokinase-type plasminogen activator gene, which is necessary for the invasive phenotype of several types of cancers, is controlled by growth factors such as epidermal growth factor, transforming growth factor a, and fibroblast growth factor which bind to and activate protein tyrosine kinase transmembrane receptors. Since these activated receptors communicate with the nucleus via a signaling pathway in which c-Raf-1, mitogen-activated protein kinase kinase 1 (MEK1), and the extracellular signal-regulated kinases are sequentially activated, we determined the effect of a specific MEK1 inhibitor (PD 098059) on urokinase expression in two squamous cell carcinoma cell lines (UM-SCC-1 and MDA-TU-138) characterized as avid secretors of the plasminogen activator. PD 098059 treatment of either cell line reduced the amount of secreted urokinase in a dose-dependent manner. In contrast, a compound (daidzein) chemically unrelated to PD 098059 had little effect on urokinase secretion. The effect of PD 098059 on urokinase secretion in UM-SCC-1 cells was reversible and correlated with decreased extracellular signal-regulated kinase 1 activity. PD 098059 caused a dose-dependent reduction in the in vitro invasiveness of UM-SCC-1 cells whereas it had little effect on proliferation rates. Transient transfection assays with a chloramphenicol acetyl transferase reporter driven by the urokinase promoter indicated that diminished secretion of the protease was largely a consequence of reduced promoter activity. These findings suggest that interfering with MEK1 may provide a novel means of controlling the invasiveness of tumors in which this signaling cascade is activated by autocrine and/or paracrine growth factors.
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PMID:Effect of PD 098059, a specific inhibitor of mitogen-activated protein kinase kinase, on urokinase expression and in vitro invasion. 896 87

Although the p38 mitogen-activated protein kinase (MAPK) has been implicated in signal transduction events, its role in regulating the Mr 92,000 type IV collagenase matrix metalloprotease-9 (MMP-9) and in vitro invasiveness in cancer has not yet been determined. We made the surprising observation that, in a human squamous cell carcinoma cell line (UM-SCC-1), phorbol ester-enhanced MMP-9 secretion and in vitro invasiveness were associated with a strong activation of the p38 MAPK and its downstream target, MAPK-activated protein kinase-2. To determine the role of p38 activation in these events, we investigated the effect of SB 203580, a novel specific p38 inhibitor, on protease expression and in vitro invasion of these cells. We found that inhibition of p38 by SB 203580 resulted in the almost complete reduction of phorbol myristate acetate-induced MMP-9 secretion but not of urokinase-type plasminogen activator secretion. In contrast, the activation of a transiently transfected wild-type MMP-9 promoter by MEKK-1, a specific c-Jun NH2-terminal kinase activator, was only marginally inhibited by the compound, arguing for the specificity of SB 203580. Moreover, phorbol myristate acetate-enhanced in vitro invasion was completely blocked by SB 203580, whereas p38 inhibition had little effect on growth. These findings suggest that activation of p38 may contribute to a more invasive phenotype in vitro, possibly via the expression of MMP-9, and that targeting of p38 using SB 203580 may provide a novel means of controlling invasion of cancers in which this MAPK is activated.
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PMID:Inhibition of the p38 mitogen-activated protein kinase by SB 203580 blocks PMA-induced Mr 92,000 type IV collagenase secretion and in vitro invasion. 951 96

Normal as well as neoplastic cells traverse extracellular matrix barriers by mobilizing proteolytic enzymes in response to epidermal growth factor (EGF)-EGF receptor (EGFR) or hepatocyte growth factor/scatter factor (SF)-c-Met interactions. The plasminogen activator-plasminogen axis has been proposed to play a key role during cell invasion, but the normal development of plasminogen activator- as well as that of plasminogen-deficient mice supports the existence of alternate proteolytic systems that permit cells to traverse extracellular matrix barriers. To characterize the role that matrix-degrading proteinases play in EGF- or SF-stimulated invasion, a human squamous carcinoma cell line (UM-SCC-1) was triggered atop the matrices of type I collagen or human dermal explants in a three-dimensional culture system. During EGF- or SF-induced invasion, UM-SCC-1 cells expressed urokinase-type plasminogen activator (uPA) and uPA receptor as well as the matrix metalloproteinases (MMPs), membrane-type MMP-1, collagenase 1, stromelysin 1, and gelatinase B. Despite the presence of a positive correlation between uPA receptor-uPA expression and growth factor-stimulated invasion, UM-SCC-1 invasion was not affected by inhibitors directed against the plasminogen activator-plasminogen axis. In contrast, both recombinant and synthetic MMP inhibitors completely suppressed invasion by either EGF- or SF-stimulated cells without affecting either proteinase expression or cell motility across collagen-coated surfaces. These data demonstrate that MMPs, but not the plasminogen activator-plasmin system, can directly regulate the ability of either EGF- or SF-stimulated tumor cells to invade interstitial matrix barriers.
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PMID:Role of the plasminogen activator and matrix metalloproteinase systems in epidermal growth factor- and scatter factor-stimulated invasion of carcinoma cells. 982 36

The plasminogen activating system plays a key role in the cascade of tumour-associated proteolysis leading to extracellular matrix degradation and stromal invasion. Changes in the expression of this system, consisting of urokinase- and tissue-type plasminogen activators (uPA and tPA, respectively), plasminogen activator inhibitors (PAI-1, PAI-2) and uPA receptor, have been associated with tumour aggressiveness in a variety of solid malignant tumours. This paper describes a study of squamous intraepithelial lesions (SILs, n=36), squamous cell carcinomas (SCCs, n=42), and normal mucosa (n=5) of the uterine cervix by in situ hybridization with (35)S-labelled RNA probes. uPA transcripts were absent from normal mucosa and non-invasive lesions, but present in atypical epithelial cells of all microinvasive carcinomas ( n=19) and in some of the more advanced invasive carcinomas (n=11). PAI-1 transcripts were found in stromal cells of most tissue samples with, however, significantly increased levels in invasive SCC compared with SIL, microinvasive SCC, and normal mucosa. uPA-positive invasive carcinomas often displayed additional PAI-1 expression by tumour cells. At variance with uPA, tPA transcripts were found in atypical epithelial cells of low- and high-grade SILs. In the majority of SCCs tested (27/29 cases), the HPV 16 E6/E7 oncogene and uPA transcription were correlated. uPA and PAI-1 expression indicates invasive growth when expressed by atypical epithelial cells of squamous cervical lesions. Moreover, the presence of uPA transcripts is indicative of early invasive growth. uPA and tPA seem to have different functions in the development of invasive properties in uterine cervical squamous epithelium.
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PMID:Urokinase gene expression indicates early invasive growth in squamous cell lesions of the uterine cervix. 1054 82

Angiogenesis is an important phenomenon for the growth and metastasis of solid tumors. The present study examined the characterization of angiogenic factors produced by human oral squamous cell carcinoma (oral SCC) cell lines established from lymph node metastatic tumors and primary tumor in different patients. The conditioned medium of HSC3 with the strongest metastatic ability among the examined lines enhanced a tube-forming activity of bovine carotid artery endothelial (BAE) cells in collagen gel cultures. The treatment of HSC3 with anti-vascular endothelial growth factor (VEGF) antibody or anti-basic fibroblast growth factor (bFGF) antibody, either alone or in combination, attenuated the activity of urokinase-type plasminogen activator (uPA) in the endothelial cells stimulated by the conditioned medium of HSC3. In contrast, neither anti-interleukin-8 (IL-8) antibody nor anti-hepatocyte growth factor (HGF beta) antibody affected uPA activity in the endothelial cells. Among these HSC cell lines, HSC3 secreted VEGF with the highest (1.92 +/- 0.24 ng/10(6) cells/24 h) level and bFGF. The level of bFGF secreted by HSC3 was lower than that secreted by BAE cells. Other oral SCC cell lines secreted lower levels of VEGF and undetectable levels of bFGF. By reverse transcriptase-polymerase chain reaction analysis of mRNA the production of VEGF121, VEGF145, VEGF165, VEGF189, and VEGF206 in these cell lines was able to be detected. Moreover, the conditioned medium of HSC3 enhanced the tyrosine phosphorylation and expression of kinase insert domain-containing receptor (KDR/flk-1) in the endothelial cells. These results suggest that oral SCC promotes angiogenesis via expression of VEGF and upregulation of their receptor KDR/flk-1 expression in endothelial cells.
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PMID:Human oral squamous cell carcinoma cell lines promote angiogenesis via expression of vascular endothelial growth factor and upregulation of KDR/flk-1 expression in endothelial cells. 1088 25


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