Activation of the {beta}-catenin/T-cell-specific transcription factor/lymphoid enhancer factor-1 pathway by plasminogen activators in ECV304 carcinoma cells.
Besides its involvement in clot lysis, the plasminogen activator (PA) system elicits various cellular responses involved in cell migration, adhesion, and proliferation and plays a key role in the progression of cancers. beta-Catenin interacts with E-cadherins and functions as transcriptional coactivator of the Wnt-signaling pathway, which is implicated in tumor formation when aberrantly activated. We report that tissue-type plasminogen activator (tPA) elicited tyrosine phosphorylation and cytosolic accumulation of an active (non-serine-threonin phosphorylated, nonubiquitinated) form of beta-catenin in ECV304 carcinoma cells. tPA-dependent beta-catenin activation is mediated through epidermal growth factor receptor (EGFR) transactivation (via Src), suggested by the inhibitory effects of AG1478 and PP2 (specific inhibitors of EGFR and Src, respectively) and by the lack of beta-catenin activation in EGFR-negative B82 fibroblasts. EGFR phosphorylation and beta-catenin activation were inhibited by plasminogen activator inhibitor 1 and pertussis toxin, two inhibitors of the urokinase-type plasminogen activator (uPA)/uPA receptor system. beta-Catenin activation was correlated with the phosphorylation of glycogen synthase kinase-3beta through a phosphatidylinositol 3-kinase/Akt-dependent mechanism. Gel shift experiments revealed the activation of beta-catenin/T-cell-specific transcription factor (Tcf)/lymphoid enhancer factor-1 (Lef) transcriptional complex, evidenced by an increased binding of nuclear extracts to oligonucleotides containing the cyclin D1 Lef/Tcf site. beta-Catenin silencing through small interfering RNA and antisense oligonucleotides inhibited both the tPA-mediated cyclin D1 expression and cell proliferation. A similar activation of the beta-catenin pathway was triggered by amino-terminal fragment, the NH(2)-terminal catalytically inactive fragment of tPA, thus suggesting that this effect was independent of the proteolytic activity of plasminogen activators. In conclusion, the beta-catenin/Lef/Tcf pathway is activated by tPA and is involved in cell cycle progression and proliferation.
Maupas-Schwalm
Françoise
F
Institut National de la Santé et de la Recherche Médicale U466, IFR31, Centre Hospitalier Universitaire Rangueil, Toulouse, France.
Robinet
Catherine
C
Augé
Nathalie
N
Thiers
Jean-Claude
JC
Garcia
Virginie
V
Cambus
Jean-Pierre
JP
Salvayre
Robert
R
Nègre-Salvayre
Anne
A
D021581:Active Transport, Cell Nucleus / Q000502:physiology; D002277:Carcinoma / Q000378:metabolism*; D002453:Cell Cycle / Q000502:physiology; D048708:Cell Growth Processes / Q000502:physiology; D045744:Cell Line, Tumor; D019938:Cyclin D1 / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D003598:Cytoskeletal Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004789:Enzyme Activation; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000502:physiology; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D051821:Lymphoid Enhancer-Binding Factor 1; D016376:Oligonucleotides, Antisense / Q000235:genetics / Q000494:pharmacology; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D034741:RNA, Small Interfering; D010959:Tissue Plasminogen Activator / Q000378:metabolism*; D015534:Trans-Activators / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D051176:beta Catenin
C495270:CTNNB1 protein, human; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; D051821:Lymphoid Enhancer-Binding Factor 1; D016376:Oligonucleotides, Antisense; D011518:Proto-Oncogene Proteins; D034741:RNA, Small Interfering; D015534:Trans-Activators; D014157:Transcription Factors; D051176:beta Catenin; D019938:Cyclin D1; D066246:ErbB Receptors; C494918:AKT1 protein, human; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D038362:Glycogen Synthase Kinase 3; D010959:Tissue Plasminogen Activator