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DNA damage induced by phorbol ester-stimulated neutrophils is augmented by extracellular cofactors. Role of histidine and metals
Journal article   Open access   Peer reviewed

DNA damage induced by phorbol ester-stimulated neutrophils is augmented by extracellular cofactors. Role of histidine and metals

Emily Shacter, Rosa L Lopez, Edward J Beecham and Siegfried Janz
The Journal of biological chemistry, Vol.265(12), pp.6693-6699
04/25/1990
DOI: 10.1016/S0021-9258(19)39206-3
PMID: 2157707
url
https://doi.org/10.1016/S0021-9258(19)39206-3View
Published (Version of record) Open Access

Abstract

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.
Cell Line Histidine - pharmacology Tetradecanoylphorbol Acetate - pharmacology Neutrophils - drug effects Tumor Cells, Cultured - drug effects Cells, Cultured Neutrophils - physiology Tumor Cells, Cultured - metabolism Amino Acids - pharmacology Hydrogen Peroxide - metabolism Animals Edetic Acid - pharmacology Superoxides - metabolism Mice Mice, Inbred BALB C DNA Damage Kinetics Plasmacytoma Leukemia L1210 Neutrophils - metabolism Hydrogen-Ion Concentration Metals - pharmacology

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