title: Oxygen-dependent fragmentation of cellular DNA by nitric oxide.
abstract: Although active oxygen species and related metabolites, such as nitric oxide (NO), have been postulated to play important roles in the apoptosis of various cells, a precise mechanism leading to cell death remains to be elucidated. Recently we found that the lifetime of NO depends greatly on the concentration of environmental oxygen and that NO reversibly inhibits mitochondrial respiration and ATP synthesis; the inhibitory effect is stronger at physiologically low oxygen tension than under atmospheric conditions (Arch. Biochem. Biophys. 323, 27-32, 1995). The present work describes the effects of the NO-generating agent, 1-hydroxy-2-oxo-3,3-bis(2-aminoethyl)-1-triazene (NOC 18) and oxygen tension on the respiration, ATP synthesis and apoptosis of HL-60 cells. When respiration was inhibited by NOC 18, cellular ATP levels decreased significantly and DNA fragmentation was elicited. Both events were enhanced by decreasing oxygen tension and suppressed by adding NO-trapping agents, such as 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO) and oxyhemoglobin. The fragmentation of cellular DNA was inhibited in a dose dependent manner by herbimycin A, a tyrosine kinase inhibitor. Fragmentation of the DNA of HL-60 cells was also induced either by peroxynitrite, superoxide or hydroxyl radical by some mechanism which was diminished by lowering the oxygen tension. These results indicated that the decrease in cellular ATP and activation of tyrosine kinase might play important roles in NO-induced apoptosis particularly under physiologically low oxygen tensions.
authors.affiliation: Institute of Medical Science, Center for Adult Diseases, Kurashiki, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Yabuki
authors.forename: Y
authors.initials: Y
authors.lastname: Inai
authors.forename: T
authors.initials: T
authors.lastname: Yoshioka
authors.forename: K
authors.initials: K
authors.lastname: Hamazaki
authors.forename: T
authors.initials: T
authors.lastname: Yasuda
authors.forename: M
authors.initials: M
authors.lastname: Inoue
authors.forename: K
authors.initials: K
authors.lastname: Utsumi
mesh_terms: D000255:Adenosine Triphosphate / Q000096:biosynthesis; D017209:Apoptosis / Q000187:drug effects; D001565:Benzoates / Q000494:pharmacology; D016227:Benzoquinones; D053938:DNA Fragmentation / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005609:Free Radicals / Q000378:metabolism; D018922:HL-60 Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D047029:Lactams, Macrocyclic; D009566:Nitrates / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism* / Q000494:pharmacology*; D009573:Nitrites / Q000494:pharmacology; D009603:Nitroso Compounds / Q000494:pharmacology; D010100:Oxygen / Q000378:metabolism*; D011809:Quinones / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D017828:Rifabutin / Q000031:analogs & derivatives
chemical_list: D001565:Benzoates; D016227:Benzoquinones; D004791:Enzyme Inhibitors; D005609:Free Radicals; D007093:Imidazoles; D047029:Lactams, Macrocyclic; C093285:NOC 18; D009566:Nitrates; D009573:Nitrites; D009603:Nitroso Compounds; D011809:Quinones; D017382:Reactive Oxygen Species; C079393:1,3-dihydroxy-4,4,5,5-tetramethyl-2-(4-carboxyphenyl)tetrahydroimidazole; D017828:Rifabutin; C039642:peroxynitric acid; D009569:Nitric Oxide; C020754:herbimycin; D000255:Adenosine Triphosphate; D010100:Oxygen