title: Hyperoxia-induced DNA damage causes decreased DNA methylation in human lung epithelial-like A549 cells.
abstract: The effect of hyperoxia on levels of DNA damage and global DNA methylation was examined in lung epithelial-like A549 cells. DNA damage was assessed by the single-cell gel electrophoresis (comet assay) and DNA methylation status by the cytosine extension assays. Cells exposed to ionizing radiation (0, 1, 2, 4, or 8 Gy) showed increasing rates of percentage of DNA in the tail and tail length with increasing radiation dose. When cells were exposed to room air (normoxia) for 1 day and 95% O2 (hyperoxia) for 1, 2, 3, 4, and 5 days, data indicated that hyperoxia caused time-dependent increases in levels of (a) single strand breaks, (b) double strand breaks, and (c) 8-oxoguanine. Decreased DNA methylation also was observed at day 5 of hyperoxic exposure, suggesting that hyperoxia-induced DNA damage can influence patterns of DNA methylation in a lung-derived cell line.
authors.affiliation: Department of Pediatrics, National Jewish Medical and Research Center, Denver, CO 80206, USA.
authors.forename: Mihalis I
authors.initials: MI
authors.lastname: Panayiotidis
authors.forename: Raymond C
authors.initials: RC
authors.lastname: Rancourt
authors.forename: Corrie B
authors.initials: CB
authors.lastname: Allen
authors.forename: Suzette R
authors.initials: SR
authors.lastname: Riddle
authors.forename: Barbara K
authors.initials: BK
authors.lastname: Schneider
authors.forename: Shama
authors.initials: S
authors.lastname: Ahmad
authors.forename: Carl W
authors.initials: CW
authors.lastname: White
mesh_terms: D045744:Cell Line, Tumor; D020552:Comet Assay / Q000379:methods; D004247:DNA / Q000032:analysis / Q000187:drug effects / Q000528:radiation effects; D004249:DNA Damage; D019175:DNA Methylation / Q000187:drug effects* / Q000528:radiation effects; D004260:DNA Repair; D004277:DNA, Single-Stranded / Q000187:drug effects / Q000528:radiation effects; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects; D006147:Guanine / Q000031:analogs & derivatives* / Q000378:metabolism; D006801:Humans; D018496:Hyperoxia / Q000503:physiopathology*; D008175:Lung Neoplasms; D010100:Oxygen / Q000633:toxicity*; D013997:Time Factors
chemical_list: D004277:DNA, Single-Stranded; C024829:8-hydroxyguanine; D006147:Guanine; D004247:DNA; D010100:Oxygen