title: DNA damage induced by 3-chloro-4-(dichloromethyl)-5-hydroxy-2[5H]-furanone (MX) in HL-60 cells and purified DNA in vitro.
abstract: Chlorinated tap water often contains 3-chloro-4-(dichloromethyl)-5-hydroxy-2[5H]-furanone (MX), which is a potent directly acting bacterial mutagen. We have investigated the induction of DNA damage by MX in a promyelocytic human leukaemia cell line (HL-60 cells). Exposure of HL-60 cells to 100-300 microM MX resulted in increased levels of DNA single-strand breaks and/or alkali-labile sites (SSBs) as detected by alkaline filter elution. When adding inhibitors of DNA break repair (AraC plus hydroxyurea), increased levels of DNA SSBs were observed at very low concentrations (1-3 microM) of MX, as observed by both alkaline filter elution and the single-cell gel electrophoresis assay. Increased DNA SSBs could also be observed if DNA repair inhibitors were added immediately after exposure to 10 microM MX, indicating that low concentrations of MX cause a relatively stable modification of DNA that may be recognized and incised by DNA repair enzyme activities. Further studies with DNA break repair inhibitors indicated that HL-60 cells exposed to 10 microM MX for 1 h repaired 50% of their initial DNA damage during a 2-h period and the repair appeared to be complete at 22 h. Analysis of MX-treated DNA by sequencing methods indicated that MX preferentially reacts with guanines in DNA.
authors.affiliation: Department of Environmental Medicine, National Institute of Public Health, Oslo, Norway.
authors.forename: U
authors.initials: U
authors.lastname: Marsteinstredet
authors.forename: G
authors.initials: G
authors.lastname: Brunborg
authors.forename: M
authors.initials: M
authors.lastname: Bjørås
authors.forename: E
authors.initials: E
authors.lastname: Søderlund
authors.forename: E
authors.initials: E
authors.lastname: Seeberg
authors.forename: L
authors.initials: L
authors.lastname: Kronberg
authors.forename: J A
authors.initials: JA
authors.lastname: Holme
mesh_terms: D003561:Cytarabine / Q000494:pharmacology; D004247:DNA / Q000737:chemistry* / Q000187:drug effects; D004249:DNA Damage; D004277:DNA, Single-Stranded / Q000737:chemistry / Q000187:drug effects; D004586:Electrophoresis / Q000379:methods; D005374:Filtration; D005663:Furans / Q000737:chemistry / Q000633:toxicity*; D006147:Guanine / Q000737:chemistry / Q000378:metabolism; D018922:HL-60 Cells / Q000187:drug effects*; D006801:Humans; D006918:Hydroxyurea / Q000494:pharmacology; D009153:Mutagens / Q000633:toxicity; D017422:Sequence Analysis, DNA
chemical_list: D004277:DNA, Single-Stranded; D005663:Furans; D009153:Mutagens; D003561:Cytarabine; D006147:Guanine; C054121:3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone; D004247:DNA; D006918:Hydroxyurea