Phorbol ester responsiveness of the glutathione S-transferase P1 gene promoter involves an inducible c-jun binding in human K562 leukemia cells.
Overexpression of the glutathione S-transferase P1 (GSTP1) gene is related to drug resistance in human cancer cells. However, the mechanisms of the transcriptional activation of this gene remain unclear. In this study, we examined the molecular mechanisms underlying phorbol ester mediated gene regulation using human K562 leukemia cells as a model. Promoter deletion analyses revealed that the activator protein-1 (AP-1) transcription factor site was crucial for 12-O-tetradecanoyl phorbol 13-acetate (TPA)-mediated GSTP1 gene transcription. Electrophoretic mobility shift assays and transient transfection analysis demonstrated that both DNA binding and transactivation activities of AP-1 were induced by TPA. By supershift analysis, we identified transcription factors c-jun and fra-1 as well as NF-E2p45 as components of the induced binding complex. These results show for the first time that the phorbol ester TPA is involved in the molecular mechanism(s) mediating the activation of the GSTP1 promoter in a human leukemia model.
Laboratoire de Recherche sur le Cancer et les Maladies du Sang (RCMS), Centre Universitaire de Luxembourg, 162A, avenue de la Faïencerie, L-1511 Luxembourg, Luxembourg.
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Borde-Chiché
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M
Diederich
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F
Morceau
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M
Wellman
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Dicato
D001665:Binding Sites; D004268:DNA-Binding Proteins / Q000378:metabolism; D050981:Erythroid-Specific DNA-Binding Factors; D005786:Gene Expression Regulation / Q000187:drug effects; D005982:Glutathione Transferase / Q000235:genetics*; D018398:Homeodomain Proteins; D006801:Humans; D020014:K562 Cells; D015778:Minor Histocompatibility Antigens; D009687:Nuclear Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000187:drug effects*; D011485:Protein Binding / Q000187:drug effects; D019253:Proto-Oncogene Proteins c-bcl-2; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D051818:Replication Protein C; D012097:Repressor Proteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014157:Transcription Factors / Q000032:analysis / Q000378:metabolism
C096816:BCL2-related protein A1; D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D018398:Homeodomain Proteins; C096063:MATA1 protein, S cerevisiae; D015778:Minor Histocompatibility Antigens; D009687:Nuclear Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016755:Proto-Oncogene Proteins c-jun; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D005982:Glutathione Transferase; D051818:Replication Protein C; D013755:Tetradecanoylphorbol Acetate