The covalent binding of acetaminophen to cellular nucleic acids as the result of the respiratory burst of neutrophils derived from the HL-60 cell line.
After being induced to differentiate into a neutrophilic type, cultures of the leukemic cell line HL-60 were able to cause the bioactivation and nucleic acid binding of acetaminophen upon stimulation of the respiratory burst. This phenomenon was found to simulate the same process as that previously shown with normal human granulocytes. Binding to both DNA and RNA of the cells was determined quantitatively by use of 14C-labeled acetaminophen congeners. Protein binding occurred to about the same extent as did RNA binding. Simultaneous labeling experiments with [ring-14C]- and [14C = O]acetaminophen further showed that the acetaminophen molecule was bound to DNA in an intact manner, while binding to RNA showed about a 50% excess binding of the acetaminophen ring relative to the carbonyl group. Experiments with certain inhibitors showed that catalase and azide ion strongly inhibited DNA binding, while superoxide dismutase had a slight stimulatory effect on binding. These results suggest a significant role for myeloperoxidase in the bioactivation process, which contrasts with the proposed bioactivation mechanism of certain arylamine compounds. A mechanism was proposed for acetaminophen binding to nucleic acids that requires the 1 e- oxidation of this substrate to its phenoxyl radical, although the production of the N-acetyl-p-benzoquinoneimine metabolite, which has been proposed to account for the extensive protein binding known to occur for acetaminophen, might also contribute to such binding. The potential genotoxicity of acetaminophen was considered in view of what might be a unique pathway which can metabolize this chemical to a nucleic acid-binding species.
Corbett
M D
MD
Food Science and Human Nutrition Department, University of Florida, Gainesville 32611.
Corbett
B R
BR
Hannothiaux
M H
MH
Quintana
S J
SJ
D000082:Acetaminophen / Q000378:metabolism*; D002460:Cell Line; D004273:DNA, Neoplasm / Q000302:isolation & purification / Q000378:metabolism*; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D006098:Granulocytes / Q000378:metabolism; D006801:Humans; D007938:Leukemia / Q000378:metabolism; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism; D012334:RNA, Neoplasm / Q000302:isolation & purification / Q000378:metabolism*; D016897:Respiratory Burst
D004273:DNA, Neoplasm; D012334:RNA, Neoplasm; D000082:Acetaminophen; D004121:Dimethyl Sulfoxide