title: NF-κB signaling is increased in HD3 cells following exposure to 1,4-benzoquinone: role of reactive oxygen species and p38-MAPK.
abstract: In utero exposure to benzene, a known environmental contaminant, is associated with increased risk of leukemia. We have previously shown that in utero benzene exposure can alter the redox-sensitive transcription factor NF-κB, and we hypothesize that this is through benzene-induced reactive oxygen species (ROS) production interfering with the signaling pathway involving NF-κB and p38-Mitogen Activated Protein Kinase (MAPK). As benzoquinone (BQ) is one of benzene's most toxic metabolites, the objectives of this study were to determine whether ROS and p38-MAPK-mediated BQ-induced increased NF-κB activity. HD3 chicken erythroblast cells were transfected with an NF-κB luciferase-linked reporter plasmid and exposed to BQ (25 μM) for 2-24 h. NF-κB activities were determined through luciferase assays; Western blotting was conducted to assess changes in protein levels in nontransfected cells; and the presence of ROS was determined via 2',7'-dichlorodihydrofluorescein diacetate (DCFDA) flow cytometric assays. Results demonstrated that NF-κB activity was significantly increased following exposure to BQ for 16 and 24 h and DCFDA assays and pretreatment with antioxidants indicated that BQ-mediated ROS production was responsible for this increase. Furthermore, decreased inhibitor of kappaB-alpha (IκB-α) expression suggests that nuclear factor-kappaB (NF-κB) translocates into the nucleus and that p38-MAPK activation through a ROS-dependent pathway mediates BQ-mediated increases in NF-κB activity. Future studies investigating the role of p38-MAPK in this pathway are warranted. Evaluating the effects of toxicant exposure on cell signaling pathways is vital for understanding mechanisms of xenobiotic-induced toxicity.
authors.affiliation: * Department of Biomedical and Molecular Sciences, Graduate Program in Pharmacology and Toxicology and.
authors.forename: Samantha E
authors.initials: SE
authors.lastname: Stokes
authors.forename: Louise M
authors.initials: LM
authors.lastname: Winn
mesh_terms: D000818:Animals; D016227:Benzoquinones / Q000378:metabolism / Q000633:toxicity*; D002460:Cell Line; D002645:Chickens; D004785:Environmental Pollutants / Q000633:toxicity*; D004900:Erythroblasts / Q000187:drug effects* / Q000378:metabolism; D049409:Luciferases, Firefly / Q000235:genetics; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D010957:Plasmids; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*; D014162:Transfection; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D016227:Benzoquinones; D004785:Environmental Pollutants; D016328:NF-kappa B; D047428:Protein Kinase Inhibitors; D017382:Reactive Oxygen Species; C004532:quinone; D049409:Luciferases, Firefly; D048051:p38 Mitogen-Activated Protein Kinases
keywords: IκB-α; NF-κB; benzoquinone; p38-MAPK; reactive oxygen species.