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)

To address the role of ras signaling in monocytic phagocytes in vivo, the expression of two dominant suppressors of in vitro ras signaling pathways, the carboxyl-terminal region of the GTPase-activating protein (GAP-C) and the DNA binding domain of the transcription factor ets-2, were targeted to this cell compartment. A 5-kb portion of the human c-fms proximal promoter was shown to direct expression of the transgenes to the monocytic lineage. As a result of the GAP-C transgene expression, ras-GTP levels were reduced in mature peritoneal macrophages by 70%. The terminal differentiation of monocytes was altered, as evidence by the accumulation of atypical monocytic cells in the blood. Mature peritoneal macrophages exhibited changes in colony-stimulating factor 1-dependent survival and structure. Further, expression of the colony-stimulating factor 1-stimulated gene urokinase plasminogen activator was inhibited in peritoneal macrophages. The results indicate that ras action is critical in monocytic cells after these cells have lost the capacity to traverse the cell cycle.
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PMID:Alterations in differentiation and behavior of monocytic phagocytes in transgenic mice that express dominant suppressors of ras signaling. 782 38

The mouse epidermal cell line 308 contains an activated Ha-ras gene and forms benign papillomas when transplanted to the skin of athymic nude mice. A radiation-associated malignant variant of this cell line, 308-10Gy5, has been isolated and shown to form squamous cell carcinomas in nude mice. To further examine the molecular events involved in malignant conversion of 308-10Gy5, we assessed the activator protein-1 (AP-1) binding and transactivating ability of 308 and 308-10Gy5. In nuclear protein extracts of 308, AP-1 sequence-specific binding to an oligonucleotide containing a single high-affinity AP-1 binding site was induced by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate, as determined by gel shift analysis. Nuclear extracts of 308-10Gy5 bound to the AP-1 oligonucleotide without treatment with tumor promoters. Not only was sequence-specific AP-1 DNA binding constitutively active in malignant versus benign tumor cells, but so was transactivation of a unique AP-1-responsive chloramphenicol acetyltransferase reporter construct, pTiCTaK. Constitutive transactivation of this AP-1-responsive reporter construct was observed in the malignant but not the benign tumor cells. Furthermore, steady-state transcript levels of the tumor-associated AP-1-responsive genes stromelysin, urokinase-type plasminogen activator, c-jun, and c-fos were higher in malignant 308-10Gy5 cells than in benign 308 cells. These results suggest that acquisition of constitutive AP-1 DNA binding and transactivation can result in sustained deregulation of gene expression. While malignant progression in keratinocytes is probably not due solely to the acquisition of constitutive cellular AP-1 activity, the effect of deregulated expression of AP-1-regulated genes, especially basement membrane-degrading enzymes, may be functionally related to malignant conversion.
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PMID:Constitutive AP-1 DNA binding and transactivating ability of malignant but not benign mouse epidermal cells. 814 9

Plasminogen activation is observed in the human epidermis during reepithelialization of epidermal defects and under certain pathological conditions. The activation reaction depends on keratinocyte-associated plasminogen activators (PAs), which convert the ubiquitous proenzyme plasminogen into the active trypsin-like serine proteinase plasmin. The PAs are controlled by PA inhibitors (PAIs), of which two major types are known: PAI-1 and PAI-2. In vitro and in vivo keratinocytes express both PAIs. In the current study, we have addressed the possible function of PAI-2 in regulating extracellular PA activity in cultured normal human epidermal keratinocytes (NHEK), the human keratinocyte cell line (HaCaT), and a Ha-ras transfected HaCaT variant (HaRas). PAI-2 was detected intracellularly in all three cell types. Whereas only the NHEK and the HaCaT cells secreted detectable levels of PAI-2 into the culture medium, all three cell types released urokinase-type PA (uPA) into the supernatants. When comparing HaCaT and HaRas cells, we found that the cell lines secreted comparable levels of uPA antigen, whereas the levels of uPA activity were low in the presence of PAI-2, indicating that PAI-2 serves to regulate uPA activity. This assumption was supported by the findings that PAI-2 formed complexes with secreted uPA and that uPA/PAI-2 complexes were present at the surface of the PAI-2-secreting HaCaT cells but not at the surface of PAI-2 nonsecreting HaRas cells. Finally, PAI-2 was found to counteract the uPA-dependent and plasmin-mediated detachment of cultured HaCaT cells. Taken together, our findings indicate that secreted PAI-2 serves to regulate the activity of extracellular uPA in keratinocytes.
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PMID:Plasminogen activator inhibitor type-2 (PAI-2) in human keratinocytes regulates pericellular urokinase-type plasminogen activator. 863

Invasive and metastatic cells require protease expression for migration through the extracellular matrix. Metastatic NIH 3T3 fibroblasts transformed by different activated ras genes showed two different protease phenotypes, rasuPA+/CL- and rasCL+/uPA- (Zhang, J-Y., and Schultz, R. M. (1992) Cancer Research 52, 6682-6689). Phenotype rasuPA+/CL- is dependent on expression of the serine-type protease urokinase plasminogen activator (uPA) and the phenotype rasCL+/uPA- on the cystine-type protease cathepsin L (CL) for lung colonization in experimental metastasis. The existence of multiple invasive phenotypes on ras-isoform transformation implied the activation of alternative pathways downstream from Ras. We now show that c-Raf-1, extracellular signal-regulated protein kinase (ERK)-1, and ERK-2 are hyperphosphorylated, and the ERK activity is high in both the uPA- and CL-dependent ras-transformed invasive phenotypes. Levels of c-Jun and c-Jun NH2-terminal kinase (JNK) activity are also high in the uPA-dependent phenotype, but they are almost undetectable in the CL-dependent phenotype. The uPA Ras-response element is a PEA3/URTF element, and mobility shift assays show a strong PEA3/URTF protein band in the uPA-dependent phenotype. This band is competed by a consensus AP-1 DNA sequence and by antibodies to PEA3 and c-Jun. Thus, the uPA-invasive phenotype appears to require the activation of Ets/PEA3 and c-Jun transcription factors activated by the ERK and JNK pathways, while the CL-invasive phenotype appears to require ERK activity with suppression of JNK and c-Jun activities. These postulates are supported by the introduction of a dominant negative c-Jun, TAM67, into cells of phenotype rasuPA+/CL-, which down-regulated the high uPA mRNA levels characteristic of this phenotype to basal levels and up-regulated basal levels of CL mRNA to levels similar to those observed in cells of phenotype rasCL+/uPA-. We conclude that the JNK pathway acts as a switch between two distinct protease phenotypes that are redundant in their abilities to grow tumors and metastasize.
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PMID:Characterization of downstream Ras signals that induce alternative protease-dependent invasive phenotypes. 903 12

Recent advance in cell-molecular biological studies have revealed various prognostic factors in lung cancer. The aim of this paper is to critically review the current status of molecular biological prognostic markers in non-small cell lung cancer. DNA ploidy, AgNORs and PCNA as marker of tumor cellular proliferative activity are reported to be a prognostic marker but still remain controversial. The proteases such as uPA, MMPs and CB catalyze degradation of the extracellular matrix and basement membranes. Although the prognostic implications of the uPA and MMPs still remain unclear, cathepsin B appears to be one of the most useful prognostic markers so far reported for non-small cell lung cancer. In a number of studies, genetic abnormalitis has been reported to be a prognostic marker in cancer patients. In non-small cell lung cancer, the prognostic implication of the altered p53 expression or ras p21 expression still remain unclear, especially p53 is conflicting. The most useful clinical prognostic marker may be obtained by the combined analysis of some prognostic information.
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PMID:[Molecular biological prognostic markers in lung cancer]. 904 11

The activation status of the ras pathway was studied in eight ovarian tumor cell lines. Three biochemical parameters indicative of ras activation were tested: (a) the ratio of the ras-GTP:ras-GDP complex; (b) the activity of mitogen-activated protein kinases p42/p44; and (c) ets-2 phosphorylation at position threonine 72, a mitogen-activated protein kinase phosphorylation site in vivo. Four of the ovarian tumor cell lines had an activated ras pathway by these three parameters, whereas only one of these contained a mutated ras gene. In addition, ras/ets-2 responsive genes such as the urokinase plasminogen activator (uPA) were activated in these four cell lines. Transient transfection assays indicated that the compound ets-AP1 oncogene responsive enhancer present in the uPA gene was the target of ras signaling in ovarian tumor cells and that the combination of activated ras and ets-2 could superactivate the uPA enhancer element. Coexpression of the dominant-negative ras-Asn17 cDNA gene abrogated activity of this uPA element in ovarian tumor cells. These data indicate that ets-2 is a nuclear target of ras action in ovarian tumor cell lines and that ras signaling pathways may be activated in ovarian cancer by mechanisms independent of direct genetic damage to ras genes.
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PMID:Activation of the ras-mitogen-activated protein kinase pathway and phosphorylation of ets-2 at position threonine 72 in human ovarian cancer cell lines. 960 74

Ras activates a multitude of downstream activities with roles in cellular proliferation, invasion and metastasis, differentiation, and programmed cell death. In this work we have evaluated the requirement of extracellular signal-regulated protein kinase (ERK), c-Jun NH2-terminal kinase kinase (JNKK), and c-Jun/AP-1 activities in transformation and extracellular matrix invasion of ras oncogene expressing NIH 3T3 fibroblasts by expressing stable mutant genes that constitutively inhibit these activities. Whereas the inhibition of ERK activity reverts the transformed and invasive phenotype, the inhibition of the JNK pathway and AP-1 trans-activating activities by JNKK[K129R] and c-Jun(TAM67) had no effect on the ability of the ras oncogene-expressing cells to grow in soft agar or invade Matrigel basement membrane. Thus an elevated JNK activity and/or c-Jun/AP-1 trans-activating activity are not absolute requirements for ras transformation or invasion through basement membrane, and the dependence on AP-1 activity for transformation is cell-specific. However, inhibition of JNK kinase (JNKK) in ras-transformed cells with normally elevated JNK activity switches the protease-dependent invasive phenotype from a urokinase plasminogen activator (uPA)-dependent to a cathepsin L (CL)-dependent invasive phenotype. Conversely, treatment of ras-transformed cells of low constitutive JNK activity with the JNK stimulator, anisomycin, converts the protease mRNA levels from those characteristic of a CL-dependent to a uPA-dependent phenotype. These protease phenotypes can be duplicated in untransformed NIH 3T3 cells that express platelet-derived growth factor receptors and m1 muscarinic receptors that selectively stimulate the ERK or JNK pathways, respectively. It is concluded that high ERK activity is required for both protease phenotypes, whereas the JNK pathway and c-Jun/AP-1 activity are not required for transformation but regulate a switch between uPA and CL protease phenotypes in both transformed and untransformed cells. In ras-transformed NIH 3T3 fibroblasts, the uPA- and CL-dependent protease phenotypes are redundant in their ability to invade through basement membrane.
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PMID:Role of mitogen-activated protein kinases and c-Jun/AP-1 trans-activating activity in the regulation of protease mRNAs and the malignant phenotype in NIH 3T3 fibroblasts. 987 19

Macrophage colony-stimulating factor (CSF-1) binds to a receptor (CSF-1R) encoded by the c-fms proto-oncogene and activates transcription of the urokinase plasminogen activator (uPA) gene in murine bone-marrow-derived macrophages. This article demonstrates that the murine macrophage cell line RAW264 responds to CSF-1 with inducible phosphorylation of cytoplasmic proteins on tyrosine residues but fails to induce transcription of uPA. The defect was correlated with a selective failure to maintain CSF-1Rs on the cell surface, whereas all RAW264 cells contained abundant CSF-1Rs within the presumptive Golgi/endoplasmic reticulum compartment. Transfection with a CSF-1R expression plasmid permitted CSF-1-dependent activation of the signalling pathway targeting an Ets/AP1 (activator protein 1) element in the uPA promoter that has been shown previously to be a target of oncogenic ras and protein kinase C pathways. Mutation of the expressed CSF-1R at either Y807 or Y559, sites of receptor tyrosine phosphorylation implicated in signal transduction, reduced but did not abolish uPA promoter activation by CSF-1. Activation by mutant CSF-1R plasmids was additive; there was no evidence of mutual complementation. The results indicate that maintenance of elevated uPA transcription by CSF-1 requires new receptors emerging continuously on the cell surface. Parallel, partly redundant, signalling pathways arising from phosphorylated tyrosines on the CSF-1R activate multiple cis-acting elements on the complex uPA promoter.
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PMID:Regulation of urokinase plasminogen activator gene transcription in the RAW264 murine macrophage cell line by macrophage colony-stimulating factor (CSF-1) is dependent upon the level of cell-surface receptor. 1072 33

In the experimental metastasis assay certain animals, from groups of similarly treated animals, develop more lung metastases than expected from random chance alone. This clustering of metastases is characterized by a power function relationship, sigma(2) = amu(b), between the variance, sigma(2), and mean, mu, of the numbers of lung metastases per animal (a and b are constants). To determine whether this clustering could be an artifact of experimental metastasis, whether it could be influenced by different experimental conditions, and to attempt to clarify its cause, 22 published data sets from experimental metastasis utilizing 2,145 mice, as well as 8 data sets from spontaneous metastasis utilizing 1,020 mice were analyzed. In these experiments cell cloning, cell-cell fusion, treatment with a protein kinase C inhibitor, treatment with cell adhesion compounds, and transfection with either the ras oncogene, the sialidase gene, or the urokinase sense and antisense genes were used to influence metastasis. They employed 14 different cell lines and 6 different strains of inbred mice. Clustering of metastasis was evident in animals from the spontaneous metastasis assays as well as from the experimental metastasis assays. It was apparent whether mice were injected with tumor cells derived from clones or from cell lines. Clustering was demonstrated within each data set, regardless of the experimental conditions employed. A single variance to mean power function (with a = 2.2 and b = 1.51) characterized the clustering in the 30 data sets. The regional distribution of blood flow through lungs and other organs is nonuniform, exhibiting a fractal symmetry on change of scale. This symmetry implies that the variance of a region's blood flow is related to its mean by the same power function as was observed with metastasis. Indeed, measurements of blood flow from isolated canine lungs yield b = 1.56, similar to the corresponding figure from murine lung metastasis. These findings lend support to the hypothesis that the observed clustering of metastases is a consequence of fractal variations in lung blood flow.
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PMID:Clustering of murine lung metastases reflects fractal nonuniformity in regional lung blood flow. 1072 73

Sodium phenylacetate (NaPa), a non-toxic phenylalanine metabolite, has been shown to induce in vivo and in vitro cytostatic and antiproliferative effects on various cell types. In this work, we analysed the effect of NaPa on the invasiveness of breast cancer cell (MDA-MB-231, MCF-7 and MCF-7 ras). Using the highly invasive breast cancer cell line MDA-MB-231, we demonstrated that an 18-hour incubation with NaPa strongly inhibits the cell invasiveness through Matrigel (86% inhibition at 20 mM of NaPa). As cell invasiveness is greatly influenced by the expression of urokinase (u-PA) and its cell surface receptor (u-PAR) as well as the secretion of matrix metalloproteinases (MMP), we tested the effect of NaPa on these parameters. An 18-hour incubation with NaPa did not modify u-PA expression, either on MDA-MB-231 or on MCF-7 and MCF-7 ras cell lines, and induced a small u-PA decrease after 3 days of treatment of MDA-MB-321 with NaPa. In contrast, an 18 h incubation of MDA-MB-231 increased the expression of u-PAR and the secretion of MMP-9. As u-PAR is a ligand for vitronectin, a composant of the extracellular matrix, these data could explain the increased adhesion of MDA-MB-231 to vitronectin, while cell adhesivity of MCF-7 and MCF-7 ras was unmodified by NaPa treatment. NaPa induced also an increased expression of both Lymphocyte Function-Associated-1 (LFA-1) and Intercellular Adhesion Molecule-1 (ICAM-1), which was obvious from 18 hour incubation with NaPa for the MDA-MB-231 cells, but was delayed (3 days) for MCF-7 and MCF-7 ras. Only neutralizing antibodies against LFA-1 reversed the decreased invasiveness of NaPa-treated cells. Therefore we can conclude that the strong inhibition of MDA-MB-231 invasiveness is not due to a decrease in proteases involved in cell migration (u-PA and MMP) but could be related both to the modification of cell structure and an increased expression of adhesion molecules such as u-PAR and LFA-1.
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PMID:Decrease of breast cancer cell invasiveness by sodium phenylacetate (NaPa) is associated with an increased expression of adhesive molecules. 1125 95


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