title: Comparison of chemically induced DNA breakage in cellular and subcellular systems using the comet assay.
abstract: The alkaline comet assay, employing a single cell gel electrophoresis, is a rapid, simple and sensitive technique for visualizing and measuring DNA damage leading to strand breakage in individual mammalian cells. In this report, we describe a modified version of this assay which we used to assess DNA damage as a result of treating lysed cells with genotoxic and antimetabolic agents. By means of this modified assay, DNA is no longer held under the regulation of any metabolic pathway or membrane barrier. Using 3 direct-acting agents, hydrogen peroxide, N-methyl-N-nitrosourea, and bleomycin, we were able to induce increased DNA migration by both the standard and modified comet assays. In contrast, with 4-nitroquinoline 1-oxide, 5-fluorouracil, and methotrexate, which require cellular enzymatic activity to induce DNA damage, we succeeded in inducing increased DNA migration using the standard comet assay conditions only. In some cases, the modified comet assay might be helpful in analyzing chemical and biological characteristics of genotoxic agents when performed in combination with the standard comet assay.
authors.affiliation: Faculty of Pharmaceutical Sciences, Nagoya City University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kasamatsu
authors.forename: K
authors.initials: K
authors.lastname: Kohda
authors.forename: Y
authors.initials: Y
authors.lastname: Kawazoe
mesh_terms: D015112:4-Nitroquinoline-1-oxide / Q000633:toxicity; D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000633:toxicity*; D001761:Bleomycin / Q000633:toxicity; D004247:DNA / Q000187:drug effects*; D004249:DNA Damage; D005472:Fluorouracil / Q000633:toxicity; D006861:Hydrogen Peroxide / Q000633:toxicity; D007939:Leukemia L1210 / Q000473:pathology; D008727:Methotrexate / Q000633:toxicity; D008770:Methylnitrosourea / Q000633:toxicity; D051379:Mice; D009152:Mutagenicity Tests; D009153:Mutagens / Q000633:toxicity*; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D000964:Antimetabolites, Antineoplastic; D009153:Mutagens; D001761:Bleomycin; D015112:4-Nitroquinoline-1-oxide; D008770:Methylnitrosourea; D004247:DNA; D006861:Hydrogen Peroxide; D005472:Fluorouracil; D008727:Methotrexate