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 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

Multiple aspects of the transformed phenotype induced in a murine mammary epithelial cell line scp-2 by expression of activated G22V M-Ras, including maintainance of cell number at low density, anchorage-independent growth, invasion of Matrigel, and secretion of matrix metalloproteinases (MMP) 2 and 9, were dependent on an autocrine mechanism. Conditioned medium from dense cultures of scp-2 cells expressing G22V M-Ras, but not from parental cells, induced activation of Erk and Akt in cells expressing G22V M-Ras, maintained the cell number and promoted anchorage-independent growth of cells expressing G22V M-Ras (although not the parental cells), and induced scattering of MDCK cells. The latter activities were blocked by neutralizing antibodies to hepatocyte growth factor/scatter factor (HGF/SF) and could be mimicked by HGF/SF. Anti-HGF/SF antibodies also inhibited invasion of Matrigel, and the production of MMP-2 and MMP-9, together with urokinase-type plasminogen activator, was secreted by G22V M-Ras scp-2 cells but not by parental cells. Invasion of Matrigel was blocked by an inhibitor of MMPs, BB94, and by the mitogen-activated protein kinase kinase 1/2 kinase inhibitor PD98059 but was only marginally affected by the phosphatidylinositol 3-kinase inhibitor LY294002. Autocrine HGF/SF was thus critical for expression of key features of the phenotype of mammary epithelial cells transformed by expression of activated M-Ras.
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PMID:Multiple aspects of the phenotype of mammary epithelial cells transformed by expression of activated M-Ras depend on an autocrine mechanism mediated by hepatocyte growth factor/scatter factor. 1514 Sep 46