DNA damage induced by phorbol ester-stimulated neutrophils is augmented by extracellular cofactors. Role of histidine and metals. J Biol Chem 1990 Apr 25;265(12):6693-9
Date
04/25/1990Pubmed ID
2157707Scopus ID
2-s2.0-0025218710 (requires institutional sign-in at Scopus site) 54 CitationsAbstract
Activated neutrophils cause extensive DNA damage in neighboring nonphagocytic cells. To determine whether compounds in the extracellular milieu participate in the DNA damage process, murine neutrophils were cocultivated with target tumor cells in media of varying composition. Using the alkaline elution assay, it was found that the level of strand breaks induced was significantly higher (2.8-fold) in complex cell culture media than in minimal phosphate-buffered saline. Addition of amino acids in general and of histidine in particular increased the level of damage nearly to that observed in complete media (2.7- and 2.1-fold, respectively). The histidine stimulation was concentration-dependent and reached a maximum at 100-400 microM. The mechanism whereby this occurred is not proven but probably derived from chelation of metals and participation in a site-specific Fenton reaction. Addition of the cell-impermeable chelator EDTA dramatically inhibited induction of strand breaks by neutrophils in complete media and prevented the enhancement of damage induced by histidine in phosphate-buffered saline. None of the effects on neutrophil-induced damage could be attributed to modulation of the oxidative burst activity of the cells (O2- and H2O2 production). Histidine also enhanced induction of strand breaks by reagent H2O2. However, EDTA had no effect or actually increased the level of damage induced by both a bolus of H2O2 and a flux of H2O2 generated by glucose oxidase. The cell-permeable chelator o-phenanthroline inhibited both neutrophil- and H2O2-induced damage. The results indicate that secondary reactions involving extracellular amino acids and metals contribute significantly to neutrophil-induced DNA damage to neighboring cells. Moreover, the data show that the mechanism whereby neutrophils induce this damage cannot be attributed solely to secretion of H2O2.
Author List
Shacter E, Lopez RL, Beecham EJ, Janz SAuthor
Siegfried Janz MD Professor in the Medicine department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
Amino AcidsAnimals
Cell Line
Cells, Cultured
DNA Damage
Edetic Acid
Histidine
Hydrogen Peroxide
Hydrogen-Ion Concentration
Kinetics
Leukemia L1210
Metals
Mice
Mice, Inbred BALB C
Neutrophils
Plasmacytoma
Superoxides
Tetradecanoylphorbol Acetate
Tumor Cells, Cultured