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)

The tumor suppressor PTEN possesses lipid and protein phosphatase activities. It has been well established that the lipid phosphatase activity is essential for its tumor-suppressive function via the phosphoinositide 3-kinase (PI3K) and Akt pathways. The precise role of the protein phosphatase activity is still unclear. In the current study, we demonstrate that overexpression of wild-type PTEN in the MCF-7 breast cancer line results in phosphatase activity-dependent decreases in the phosphorylation of ETS-2, which is a transcription factor whose DNA-binding ability is controlled by phosphorylation. Exposure of MCF-7 cells to insulin, insulin-like growth factor 1 (IGF-1) or epidermal growth factor (EGF) can lead to the phosphorylation of ETS-2, Akt and ERK1/2. The MEK inhibitor PD590089 abrogates insulin-stimulated phosphorylation of ETS-2. In contrast, the PI3K inhibitor LY492002 has no effect on insulin-stimulated phosphorylation of ETS-2, despite the fact that it diminishes insulin-stimulated phosphorylation of Akt. Interestingly, overexpression of PTEN in MCF-7 leads to blockade of insulin-stimulated, but not EGF-stimulated, phosphorylation of ERK, accompanied by dramatic decreases in ETS-2 phosphorylation. We further show that the relationship of PTEN and ETS-2 has functional significance by demonstrating that PTEN abrogates activation of the uPA Ras-responsive enhancer, a target of ETS-2 action, in a phosphatase-dependent manner, irrespective of the presence or absence of insulin. Our observations, therefore, suggest that PTEN blocks insulin-stimulated ETS-2 phosphorylation through inhibition of the ERK members of the MAP kinase family independently of PI3K, and that the PTEN effect on the phosphorylation status of ETS-2 may be mediated through PTEN's protein phosphatase activity.
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PMID:PTEN blocks insulin-mediated ETS-2 phosphorylation through MAP kinase, independently of the phosphoinositide 3-kinase pathway. 1209 11

Activation of phosphoinositide 3-kinase (PI3-kinase) is involved in many cellular responses. FGF-2 is one of the potent inducers of urokinase-type plasminogen activator (uPA) production in endothelial cells. However, little is known about the molecular mechanisms underlying FGF-2-mediated uPA production. Here we examined the signal transduction pathways involved in the regulation of uPA production by FGF-2-treatment. FGF-2 potently upregulated uPA production in murine brain capillary endothelial cells (IBE cells), as well as porcine aortic endothelial (PAE) cells and L6 myoblasts ectopically expressing FGFR1. PI3-kinase inhibitors, wortmannin and LY294002, both enhanced FGF-2-dependent uPA production by these cells. Stable expression of activated mutant p110alpha catalytic subunit of PI3-kinase into IBE cells decreased FGF-2-mediated uPA production, suggesting that PI3-kinase exhibited the negative regulatory effect on uPA production. No increase in FGF-2-induced PI3-kinase activity was observed in proteins immunoprecipitated by anti-phosphotyrosine antibody. Although stable expression of deleted mutant p85alpha regulatory subunit, which lacks association with p110 catalytic subunit, in IBE cells showed no dominant negative effect, transient expression of dominant negative Ras inhibited FGF-2-mediated PI3-kinase activation. These results suggest that only activated Ras contributed the FGF-2-mediated PI3-kinase activation. In cells stably expressing mutant p85alpha subunit, FGF-2 efficiently induced uPA production. Taken together, activation of PI3-kinase by FGF-2 is Ras-dependent and results in down-regulation of uPA production.
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PMID:Negative regulation of urokinase-type plasminogen activator production through FGF-2-mediated activation of phosphoinositide 3-kinase. 1237 Aug 24

OBJECTIVE: To analyze the relationship between metastatic potential and related facters of colorectal tumor cell lines. METHODS: The variants HT-29c and HT-29d cell lines derived from the selection of HT-29 cells were injected into nude rats and the metastatic potential of the two tumor cell variants was analyzed. Expression of urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor type 1 (PAI-1) were measured with ELISA in vitro in colorectal carcinoma cell lines WiDr, HT-29 and HT-29d. Expression of carcinoembryonic antigen (CEA) and phosphoinositide 3-kinase (PI3-Kinase) were determined with immunohistochemistry, (IHC) in vitro and in vivo in WiDr, HT-29 and HT-29d cell lines. In addition, CEA expression was demonstrated with fluorescence activated cell sorter (FACS) in vitro. RESULTS: The liver metastasis rate of the variant HT-29d (with 4 cycles of selection), increased as compared with that of parental HT-29 cells and that of variant HT-29b cells (with 2 cycle of selection). The uPA concentration of variant HT-29d cell line was significantly higher than that of the non metastatic WiDr and the low metastatic HT-29 cells (P<0.05). The variant HT-29d cells produced stronger PI3-kinase expression as compared with the non-anetastatic WiDr cells and the low metastatic HT-29 cells in vivo. CONCLUSION: The selected variant cell lines can exhibit an enhanced metastatic potential. The level of uPA and PAI-1 are positively correlated with the metastatic capacity of tumor cells. The expression of PI3 kinasecorrelates with tumor development and metastasis.
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PMID:[Comparative analysis of metastatic variants from the colorectal tumor cell line HT-29] 1260 85

Autotaxin, a lysophospholipase D producing lysophosphatidic acid, augments invasive and metastatic potential of tumor cells. Current investigations have focused on understanding the molecular mechanisms by which autotaxin regulates the expression of a major mediator of tumor invasion and metastasis, urokinase-type plasminogen activator (uPA) in human A2058 melanoma cells. Autotaxin induced uPA expression in a dose-dependent manner that was inhibited by pharmacological inhibitors for Gi (pertussis toxin), phosphoinositide 3-kinase (PI3K, LY294002), Akt inhibitor (AktI), proteosome activity and IkappaB phosphorylation (pyrrolidine dithiocarbamate), and by a dominant negative mutant (DN) of Akt. Autotaxin phosphorylated Akt and induced the translocation of nuclear [corrected] factor-kappaB (NF-kappaB) to the nucleus that were inhibited by AktI or by overexpressing DN-Akt. Consistently, green fluorescence protein-tagged p65 of NF-kappaB accumulated in the nucleus by autotaxin that was abrogated when the cells were transfected with DN-Akt. Moreover, autotaxin increased the DNA binding ability of NF-kappaB and promoter activity of uPA. Collectively, these data strongly suggest autotaxin induces uPA expression via the Gi-PI3K-Akt-NF-kappaB signaling pathway that might be critical for autotaxin-induced tumor cell invasion and metastasis.
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PMID:Autotaxin stimulates urokinase-type plasminogen activator expression through phosphoinositide 3-kinase-Akt-nuclear [corrected] factor kappa B signaling cascade in human melanoma cells. 1701 94

Activated phosphoinositide 3-kinase (PI3K) and its downstream target Akt/PKB are important signaling molecules and key survival factors involved in the control of cell proliferation, apoptosis and oncogenesis. We investigated the role of the PI3K-Akt signaling pathway in the invasion of prostate cancer cell lines and activation of this pathway in primary human prostate tumors. Treatment of human prostate cancer cells viz. LNCaP, PC-3 and DU145 with PI3K pharmacological inhibitor, LY294002, potentially suppressed the invasive properties in each of these cell lines. Restoration of the PTEN gene to highly invasive prostate cancer PC-3 cells or expression of a dominant negative version of the PI3K target, Akt also significantly inhibited invasion and downregulated protein expression of urokinase-type plasminogen activator (uPA) and matrix metalloproteinase (MMP)-9, markers for cell invasion, indicating a central role of the PI3K-Akt pathway in this process. Immunoblot analysis of PI3K and total/activated levels of Akt showed increased protein levels of catalytic (p110alpha/beta) and regulatory (p85) subunits of PI3K and constitutive Akt activation in high-grade tumors compared to low-grade tumor and benign tissue. Immunohistochemical analyses further confirmed a progressive increase in p-Akt (p-Ser473) levels but not of total-Akt (Akt1/2) in cancer tissues compared to benign specimens. A successive increase in p-Akt expression was further noted in specimens serially obtained from individuals with time-course disease progression. Taken together, these results suggest that aberrant activation of PI3K-Akt pathway may contribute to increased cell invasiveness and facilitate prostate cancer progression.
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PMID:Activation of PI3K-Akt signaling pathway promotes prostate cancer cell invasion. 1755 21

Aggressive and infiltrative invasion is one of the hallmarks of glioblastoma. Low-density lipoprotein receptor-related protein (LRP) is expressed by glioblastoma, but the role of this receptor in astrocytic tumor invasion remains poorly understood. We show that activation of protein kinase C-alpha (PKC-alpha) phosphorylated and down-regulated LRP expression. Pretreatment of tumor cells with PKC inhibitors, phosphoinositide 3-kinase (PI3K) inhibitor, PKC-alpha small interfering RNA (siRNA), and short hairpin RNA abrogated phorbol 12-myristate 13-acetate-induced down-regulation of LRP and inhibited astrocytic tumor invasion in vitro. In xenograft glioblastoma mouse model and in vitro transmembrane invasion assay, LRP-deficient cells, which secreted high levels of urokinase-type plasminogen activator (uPA), invaded extensively the surrounding normal brain tissue, whereas the LRP-overexpressing and uPA-deficient cells did not invade into the surrounding normal brain. siRNA, targeted against uPA in LRP-deficient clones, attenuated their invasive potential. Taken together, our results strongly suggest the involvement of PKC-alpha/PI3K signaling pathways in the regulation of LRP-mediated astrocytoma invasion. Thus, a strategy of combining small molecule inhibitors of PKC-alpha and PI3K could provide a new treatment paradigm for glioblastomas.
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PMID:Protein kinase C-alpha-mediated regulation of low-density lipoprotein receptor related protein and urokinase increases astrocytoma invasion. 1797 65

We have previously reported that Bcl-w enhances the invasiveness of gastric cancer cells by inducing MMP-2 expression via phosphoinositide 3-kinase (PI3K), Akt and Sp1. This study demonstrates that Bcl-w additionally induces uPA expression and FAK activation. Analyses of the hierarchical relationship and functions of these components showed that the PI3K-Akt-Sp1 pathway also mediates the induction of uPA, and that both uPA and MMP-2 contribute to Bcl-w-induced invasion via the stimulation of the FAK-dependent migratory pathway. These findings significantly advance our understandings of the Bcl-w-induced signaling processes that results in the migration and invasion of cancer cells.
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PMID:Signaling components involved in Bcl-w-induced migration of gastric cancer cells. 1909 87

This study first investigates the anti-metastatic effect of alpha-tomatine in the human lung adenocarcinoma cell line: A549. In this study, we first noted alpha-tomatine inhibited A549 cells invasion and migration by wound-healing assay and Boyden chamber assay. The data also showed alpha-tomatine could inhibit phosphorylation of Akt and extracellular signal-regulated kinase 1 and 2 (ERK1/2), which is involved in the up-regulating matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9) or urokinase-type plasminogen activator (u-PA), whereas it did not affect phosphorylation of c-Jun N-terminal kinase (JNK) and p38. Next, alpha-tomatine significantly decreased the nuclear levels of nuclear factor kappa B (NF-kappaB), c-Fos, and c-Jun. Also, treating A549 cells with alpha-tomatine also leads to a dose-dependent inhibition on the binding abilities of NF-kappaB and activator protein-1 (AP-1). Further, the treatment of inhibitors specific for PI3K (Wortmannin) or ERK (U0126) to A549 cells could cause reduced activities of MMP-2, MMP-9, and u-PA. These results showed alpha-tomatine could inhibit the metastatic ability of A549 cells by reducing MMP-2, MMP-9, and u-PA activities through suppressing phosphoinositide 3-kinase/Akt (PI3K/Akt) or ERK1/2 signaling pathway and inhibition NF-kappaB or AP-1 binding activities. These findings proved alpha-tomatine might be an anti-metastatic agent against human lung adenocarcinoma.
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PMID:Alpha-tomatine inactivates PI3K/Akt and ERK signaling pathways in human lung adenocarcinoma A549 cells: effect on metastasis. 1945 46

The peroxiredoxin family of peroxidase has six mammalian members (Prx 1-6). Considering their frequent up-regulation in cancer cells, Prxs may contribute to cancer cells' survival in face of oxidative stress. Here, we show that Prx 6 promotes the invasiveness of lung cancer cells, accompanied by an increase in the activity of phosphoinositide 3-kinase (PI3K), the phosphorylation of p38 kinase and Akt, and the protein levels of uPA. Functional studies reveal that these components support Prx 6-induced invasion in the sequence p38 kinase/PI3K, Akt, and uPA. The findings provide a new understanding of the action of Prx 6 in cancer.
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PMID:Peroxiredoxin 6 promotes lung cancer cell invasion by inducing urokinase-type plasminogen activator via p38 kinase, phosphoinositide 3-kinase, and Akt. 1993 38

Peroxiredoxins (PRDX) are a family of thiol-dependent peroxidases. Among the six mammalian members of this family, PRDX6 is the only protein that additionally exhibits phospholipase A(2) (PLA(2)) activity. The physiologic role of this interesting PRDX6 feature is largely unknown at present. In this study, we show that PRDX6 increases the metastatic potential of lung cancer cells. Functional analyses of the enzymatic activities of PRDX6, using specific pharmacologic inhibitors and mutagenesis studies, reveal that both peroxidase and PLA(2) activities are required for metastasis. Specifically, peroxidase activity facilitates the growth of cancer cells, and PLA(2) activity promotes invasiveness. Further investigation of the latter event discloses that PLA(2) activity promotes accumulation of arachidonic acid, which, in turn, induces the invasive pathway involving p38 kinase, phosphoinositide 3-kinase, Akt, and urokinase-type plasminogen activator. This study is the first to define the functions of the enzymatic activities of PRDX6 in metastasis and to show the involvement of arachidonic acid in PRDX6 action in intact cells. These novel findings provide a significant step toward elucidating the role of PRDX6 in cancer and the mechanism of its action. Mol Cancer Ther; 9(4); 825-32. (c)2010 AACR.
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PMID:Phospholipase A2 activity of peroxiredoxin 6 promotes invasion and metastasis of lung cancer cells. 2035 23


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