title: A549 subclones demonstrate heterogeneity in toxicological sensitivity and antioxidant profile.
abstract: In A549 cell culture, significant variability was found in sensitivity to actinomycin D. Using limiting dilution, actinomycin D-susceptible (G4S) and -resistant (D3R) subclones were isolated. G4S cells were also susceptible to protein synthesis inhibitors, a redox cycling quinone, and an electrophile with concomitant activation of caspases 3 and 9. D3R cells were resistant to these agents without caspase activation. Antioxidant profiles revealed that D3R cells had significantly higher glutathione and glutathione reductase activity but markedly lower catalase, glutathione peroxidase, and aldehyde reductase activities than G4S cells. Thus A549 cells contain at least two distinct subpopulations with respect to predisposition to cell death and antioxidant profile. Because sensitivities to agents and the antioxidant profile were inconsistent, mechanisms independent of antioxidants, including the apparent inability to activate caspases in D3R cells, may play an important role. Regardless, the results suggest that antioxidant profiles of asymmetrical cell populations cannot predict sensitivity to oxidants and warn that the use of single subclones is advisable for mechanistic studies using A549 or other unstable cell lines.
authors.affiliation: Department of Environmental Health Sciences, School of Public Health and Center for Free Radical Biology, University of Alabama, Birmingham 35294-0022, USA.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Watanabe
authors.forename: Dale A
authors.initials: DA
authors.lastname: Dickinson
authors.forename: David M
authors.initials: DM
authors.lastname: Krzywanski
authors.forename: Karen E
authors.initials: KE
authors.lastname: Iles
authors.forename: Hongqiao
authors.initials: H
authors.lastname: Zhang
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Venglarik
authors.forename: Henry Jay
authors.initials: HJ
authors.lastname: Forman
mesh_terms: D000230:Adenocarcinoma; D000447:Aldehydes / Q000494:pharmacology; D000841:Anisomycin / Q000494:pharmacology; D000975:Antioxidants / Q000378:metabolism*; D017209:Apoptosis / Q000502:physiology; D020169:Caspases / Q000378:metabolism; D003603:Cytotoxins / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D018740:Genetic Heterogeneity; D005978:Glutathione / Q000378:metabolism; D006131:Growth Inhibitors / Q000494:pharmacology; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D008175:Lung Neoplasms; D008297:Male; D009285:Naphthoquinones / Q000494:pharmacology; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000502:physiology*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D013482:Superoxide Dismutase / Q000378:metabolism; D014407:Tumor Cells, Cultured / Q000166:cytology / Q000187:drug effects / Q000378:metabolism
chemical_list: D000447:Aldehydes; D000975:Antioxidants; D003603:Cytotoxins; D006131:Growth Inhibitors; D009285:Naphthoquinones; D011500:Protein Synthesis Inhibitors; D003609:Dactinomycin; C063002:2,3-dimethoxy-1,4-naphthoquinone; D000841:Anisomycin; D006861:Hydrogen Peroxide; D013482:Superoxide Dismutase; D020169:Caspases; D005978:Glutathione; C027576:4-hydroxy-2-nonenal