title: A Central Role for JNK/AP-1 Pathway in the Pro-Oxidant Effect of Pyrrolidine Dithiocarbamate through Superoxide Dismutase 1 Gene Repression and Reactive Oxygen Species Generation in Hematopoietic Human Cancer Cell Line U937.
abstract: Pyrrolidine dithiocarbamate (PDTC) known as antioxidant and specific inhibitor of NF-κB was also described as pro-oxidant by inducing cell death and reactive oxygen species (ROS) accumulation in cancer. However, the mechanism by which PDTC indices its pro-oxidant effect is unknown. Therefore, we aimed to evaluate the effect of PDTC on the human Cu/Zn superoxide dismutase 1 (SOD1) gene transcription in hematopoietic human cancer cell line U937. We herein show for the first time that PDTC decreases SOD1 transcripts, protein and promoter activity. Furthermore, SOD1 repression by PDTC was associated with an increase in oxidative stress as evidenced by ROS production. Electrophoretic mobility-shift assays (EMSA) show that PDTC increased binding of activating protein-1 (AP-1) in dose dependent-manner suggesting that the MAPkinase up-stream of AP-1 is involved. Ectopic NF-κB p65 subunit overexpression had no effect on SOD1 transcription. In contrast, in the presence of JNK inhibitor (SP600125), p65 induced a marked increase of SOD1 promoter, suggesting that JNK pathway is up-stream of NF-κB signaling and controls negatively its activity. Indeed, using JNK deficient cells, PDTC effect was not observed nether on SOD1 transcription or enzymatic activity, nor on ROS production. Finally, PDTC represses SOD1 in U937 cells through JNK/c-Jun phosphorylation. Taken together, these results suggest that PDTC acts as pro-oxidant compound in JNK/AP-1 dependent-manner by repressing the superoxide dismutase 1 gene leading to intracellular ROS accumulation.
authors.affiliation: Unidad de Reumatología, Nivel plaza del Instituto Autónomo Hospital Universitario de Los Andes. Mérida, Venezuela.
authors.forename: Humberto
authors.initials: H
authors.lastname: Riera
authors.affiliation: INSERM U1029, Laboratoire de l'Angiogenèse et du Microenvironnement des Cancers, Pessac, France.
authors.forename: Valéry
authors.initials: V
authors.lastname: Afonso
authors.affiliation: UMR 8601, Laboratoire de Chimie & Biochimie Pharmacologique, Paris, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Collin
authors.affiliation: INSERM U1029, Laboratoire de l'Angiogenèse et du Microenvironnement des Cancers, Pessac, France.
authors.forename: Abderrahim
authors.initials: A
authors.lastname: Lomri
mesh_terms: D000818:Animals; D002461:Cell Line, Transformed; D045744:Cell Line, Tumor; D015536:Down-Regulation; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D055786:Gene Knockout Techniques; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000172:deficiency / Q000378:metabolism*; D020935:MAP Kinase Signaling System; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011759:Pyrrolidines / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*; D013482:Superoxide Dismutase / Q000235:genetics*; D000072105:Superoxide Dismutase-1; D013859:Thiocarbamates / Q000494:pharmacology*; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D014158:Transcription, Genetic; D020298:U937 Cells
chemical_list: D016328:NF-kappa B; D009687:Nuclear Proteins; D011759:Pyrrolidines; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; C000606290:SOD1 protein, human; D013859:Thiocarbamates; D018808:Transcription Factor AP-1; C020972:pyrrolidine dithiocarbamic acid; C000606291:Sod1 protein, mouse; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; D048031:JNK Mitogen-Activated Protein Kinases