Benzene's metabolites alter c-MYB activity via reactive oxygen species in HD3 cells

Toxicol Appl Pharmacol. 2007 Jul 15;222(2):180-9. doi: 10.1016/j.taap.2007.04.016. Epub 2007 May 21.

Abstract

Benzene is a known leukemogen that is metabolized to form reactive intermediates and reactive oxygen species (ROS). The c-Myb oncoprotein is a transcription factor that has a critical role in hematopoiesis. c-Myb transcript and protein have been overexpressed in a number of leukemias and cancers. Given c-Myb's role in hematopoiesis and leukemias, it is hypothesized that benzene interferes with the c-Myb signaling pathway and that this involves ROS. To investigate our hypothesis, we evaluated whether benzene, 1,4-benzoquinone, hydroquinone, phenol, and catechol generated ROS in chicken erythroblast HD3 cells, as measured by 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate (DCFDA) and dihydrorhodamine-123 (DHR-123), and whether the addition of 100 U/ml of the antioxidating enzyme superoxide dismutase (SOD) could prevent ROS generation. Reduced to oxidized glutathione ratios (GSH:GSSG) were also assessed as well as hydroquinone and benzoquinone's effects on c-Myb protein levels and activation of a transiently transfected reporter construct. Finally we attempted to abrogate benzene metabolite mediated increases in c-Myb activity with the use of SOD. We found that benzoquinone, hydroquinone, and catechol increased DCFDA fluorescence, increased DHR-123 fluorescence, decreased GSH:GSSG ratios, and increased reporter construct expression after 24 h of exposure. SOD was able to prevent DCFDA fluorescence and c-Myb activity caused by benzoquinone and hydroquinone only. These results are consistent with other studies, which suggest metabolite differences in benzene-mediated toxicity. More importantly, this study supports the hypothesis that benzene may mediate its toxicity through ROS-mediated alterations in the c-Myb signaling pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetyltransferases / genetics
  • Animals
  • Benzene / metabolism
  • Benzene / toxicity*
  • Benzene Derivatives / metabolism
  • Benzene Derivatives / toxicity*
  • Benzoquinones / toxicity
  • Carcinogens / toxicity
  • Cell Line
  • Chickens
  • Dose-Response Relationship, Drug
  • Erythroblasts / cytology
  • Erythroblasts / drug effects
  • Erythroblasts / metabolism
  • Fluoresceins / chemistry
  • Fluoresceins / metabolism
  • Fluorescence
  • Free Radical Scavengers / pharmacology
  • Glutathione / metabolism
  • Glutathione Disulfide / metabolism
  • Hydroquinones / toxicity
  • Immunoblotting
  • Luciferases / genetics
  • Luciferases / metabolism
  • Phenol / toxicity
  • Polyethylene Glycols / pharmacology
  • Promoter Regions, Genetic / genetics
  • Proto-Oncogene Proteins c-myb / metabolism*
  • Reactive Oxygen Species / metabolism*
  • Rhodamines / chemistry
  • Rhodamines / metabolism
  • Superoxide Dismutase / pharmacology
  • Transfection

Substances

  • Benzene Derivatives
  • Benzoquinones
  • Carcinogens
  • Fluoresceins
  • Free Radical Scavengers
  • Hydroquinones
  • Proto-Oncogene Proteins c-myb
  • Reactive Oxygen Species
  • Rhodamines
  • dihydrorhodamine 123
  • diacetyldichlorofluorescein
  • Phenol
  • quinone
  • Polyethylene Glycols
  • Luciferases
  • Superoxide Dismutase
  • polyethylene glycol-superoxide dismutase
  • Acetyltransferases
  • mim-1 protein, Gallus gallus
  • Glutathione
  • Benzene
  • Glutathione Disulfide
  • hydroquinone