title: Expression of glutathione S-transferase P1-1 in leukemic cells is regulated by inducible AP-1 binding.
abstract: Glutathione S-transferases (GST) are involved in cellular protection against xenobiotics, oxidative stress as well as in resistance against chemotherapeutic compounds such as doxorubicin. Levels of human placental type GSTP1-1 are known to be increased in many tumors and hematopoietic diseases. In this work, we compare transcriptional mechanisms in cells that express or not GSTP1-1. Transient transfection assays are used to show that different GST-promoter reporter constructs generate cell-type specific levels of luciferase activity. In expressing cells, transcriptional activity is strongly dependent on AP-1 binding elements within the -65 to -75 bp region of the GSTP1 gene as shown by site-directed mutagenesis. Electrophoretic mobility shift assays show that DNA binding activity is exclusively observed in GSTP1-1-expressing cells and is increased after stimulation with hydrogen peroxide, TPA, tert-butylhydroquinone and doxorubicin. Non-expressing cells present neither constitutive nor inducible AP-1 binding. Taken together, our results provide evidence for the induction of the GSTP1 gene via AP-1 binding activity in leukemia cells and contribute to a better understanding of the molecular events regulating genes involved in drug resistance mechanisms.
authors.affiliation: Laboratoire de Biologie Moléculaire et Cellulaire du Cancer, Hôpital Kirchberg, 9, rue Edward Steichen, L-2540 Luxembourg, Luxembourg.
authors.forename: Annelyse
authors.initials: A
authors.lastname: Duvoix
authors.forename: Michaël
authors.initials: M
authors.lastname: Schnekenburger
authors.forename: Sylvie
authors.initials: S
authors.lastname: Delhalle
authors.forename: Romain
authors.initials: R
authors.lastname: Blasius
authors.forename: Patricia
authors.initials: P
authors.lastname: Borde-Chiché
authors.forename: Franck
authors.initials: F
authors.lastname: Morceau
authors.forename: Mario
authors.initials: M
authors.lastname: Dicato
authors.forename: Marc
authors.initials: M
authors.lastname: Diederich
mesh_terms: D001665:Binding Sites; D004317:Doxorubicin / Q000494:pharmacology; D024202:Electrophoretic Mobility Shift Assay; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D006873:Hydroquinones / Q000494:pharmacology; D007527:Isoenzymes / Q000096:biosynthesis* / Q000235:genetics; D019169:Jurkat Cells; D020014:K562 Cells; D007938:Leukemia; D016297:Mutagenesis, Site-Directed; D011401:Promoter Regions, Genetic; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D018808:Transcription Factor AP-1 / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection; D020298:U937 Cells
chemical_list: D006873:Hydroquinones; D007527:Isoenzymes; D018808:Transcription Factor AP-1; D004317:Doxorubicin; D006861:Hydrogen Peroxide; C018855:2-tert-butylhydroquinone; C496556:GSTP1 protein, human; D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase; D013755:Tetradecanoylphorbol Acetate