Chlorinated benzenes cause concomitantly oxidative stress and induction of apoptotic markers in lung epithelial cells (A549) at nonacute toxic concentrations

J Proteome Res. 2011 Feb 4;10(2):363-78. doi: 10.1021/pr1005718. Epub 2010 Dec 21.


In industrialized countries, people spend more time indoors and are therefore increasingly exposed to volatile organic compounds that are emitted at working places and from consumer products, paintings, and furniture, with chlorobenzene (CB) and 1,2-dichlorobenzene (DCB) being representatives of the halogenated arenes. To unravel the molecular effects of low concentrations typical for indoor and occupational exposure, we exposed human lung epithelial cells to CB and DCB and analyzed the effects on the proteome level by 2-D DIGE, where 860 protein spots were detected. A set of 25 and 30 proteins were found to be significantly altered due to exposure to environmentally relevant concentrations of 10(-2) g/m(3) of CB or 10(-3) g/m(3) of DCB (2.2 and 0.17 ppm), respectively. The most enriched pathways were cell death signaling, oxidative stress response, protein quality control, and metabolism. The involvement of oxidative stress was validated by ROS measurement. Among the regulated proteins, 28, for example, voltage-dependent anion-selective channel protein 2, PDCD6IP protein, heat shock protein beta-1, proliferating cell nuclear antigen, nucleophosmin, seryl-tRNA synthetase, prohibitin, and protein arginine N-methyltransferase 1, could be correlated with the molecular pathway of cell death signaling. Caspase 3 activation by cleavage was confirmed for both CB and DCB by immunoblotting. Treatment with CB or DCB also caused differential protein phosphorylation, for example, at the proteins HNRNP C1/C2, serine-threonine receptor associated protein, and transaldolase 1. Compared to previous results, where cells were exposed to styrene, for the chlorinated aromatic substances besides oxidative stress, apoptosis was found as the predominant cellular response mechanism.

MeSH terms

  • Apoptosis / drug effects*
  • Biomarkers / metabolism
  • Caspase 3 / metabolism
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Chlorobenzenes / toxicity*
  • Dose-Response Relationship, Drug
  • Electrophoresis, Gel, Two-Dimensional
  • Flow Cytometry
  • Humans
  • Lung / cytology
  • Lung / drug effects*
  • Lung / metabolism
  • Occupational Exposure
  • Oxidative Stress / drug effects*
  • Phosphoproteins / metabolism
  • Phosphorylation / drug effects
  • Proteome / metabolism
  • Reactive Oxygen Species / metabolism
  • Respiratory Mucosa / cytology
  • Respiratory Mucosa / drug effects*
  • Toxicity Tests
  • Volatile Organic Compounds / toxicity


  • Biomarkers
  • Chlorobenzenes
  • Phosphoproteins
  • Proteome
  • Reactive Oxygen Species
  • Volatile Organic Compounds
  • CASP3 protein, human
  • Caspase 3