Pei-Lin Li , Chun-Hua Huang , Li Mao , Jun Li , Zhi-Guo Sheng , Ben-Zhan Zhu
{"title":"An unprecedented free radical mechanism for the formation of DNA adducts by the carcinogenic N-sulfonated metabolite of aristolochic acids","authors":"Pei-Lin Li , Chun-Hua Huang , Li Mao , Jun Li , Zhi-Guo Sheng , Ben-Zhan Zhu","doi":"10.1016/j.freeradbiomed.2023.05.005","DOIUrl":null,"url":null,"abstract":"<div><p><span><span>The carcinogenicity of </span>aristolochic acids (AAs) has been attributed mainly to the formation of stable DNA-aristolactam (DNA-AL) adducts by its reactive </span><em>N</em>-sulfonated metabolite N-sulfonatooxyaristolactam (N–OSO<sub>3</sub><sup>-</sup><span>-AL). The most accepted mechanism for such DNA-AL adduct formation is via the postulated but never unequivocally-confirmed aristolactam nitrenium ion. Here we found that both sulfate radical and two ALI-derived radicals (N-centered and C-centered spin isomers) were produced by N–OSO</span><sub>3</sub><sup>-</sup><span>-ALI, which were detected and unequivocally identified by complementary applications of ESR spin-trapping, HPLC-MS coupled with deuterium-exchange methods. Both the formation of the three radical species and DNA-ALI adducts can be significantly inhibited (up to 90%) by several well-known antioxidants, typical radical scavengers, and spin-trapping agents. Taken together, we propose that N–OSO</span><sub>3</sub><sup>-</sup><span>-ALI decomposes mainly via a new N–O bond homolysis rather than the previously proposed heterolysis pathway, yielding reactive sulfate and ALI-derived radicals, which are together and in concert responsible for forming DNA-ALI adducts. This study presents strong and direct evidence for the production of free radical intermediates during N–OSO</span><sub>3</sub><sup>-</sup>-ALI decomposition, providing an unprecedented free radical perspective and conceptual breakthrough, which can better explain and understand the molecular mechanism for the formation of DNA-AA adducts, the carcinogenicity of AAs and their potential prevention.</p></div>","PeriodicalId":12407,"journal":{"name":"Free Radical Biology and Medicine","volume":null,"pages":null},"PeriodicalIF":7.1000,"publicationDate":"2023-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Free Radical Biology and Medicine","FirstCategoryId":"3","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0891584923004100","RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"BIOCHEMISTRY & MOLECULAR BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
The carcinogenicity of aristolochic acids (AAs) has been attributed mainly to the formation of stable DNA-aristolactam (DNA-AL) adducts by its reactive N-sulfonated metabolite N-sulfonatooxyaristolactam (N–OSO3--AL). The most accepted mechanism for such DNA-AL adduct formation is via the postulated but never unequivocally-confirmed aristolactam nitrenium ion. Here we found that both sulfate radical and two ALI-derived radicals (N-centered and C-centered spin isomers) were produced by N–OSO3--ALI, which were detected and unequivocally identified by complementary applications of ESR spin-trapping, HPLC-MS coupled with deuterium-exchange methods. Both the formation of the three radical species and DNA-ALI adducts can be significantly inhibited (up to 90%) by several well-known antioxidants, typical radical scavengers, and spin-trapping agents. Taken together, we propose that N–OSO3--ALI decomposes mainly via a new N–O bond homolysis rather than the previously proposed heterolysis pathway, yielding reactive sulfate and ALI-derived radicals, which are together and in concert responsible for forming DNA-ALI adducts. This study presents strong and direct evidence for the production of free radical intermediates during N–OSO3--ALI decomposition, providing an unprecedented free radical perspective and conceptual breakthrough, which can better explain and understand the molecular mechanism for the formation of DNA-AA adducts, the carcinogenicity of AAs and their potential prevention.
期刊介绍:
Free Radical Biology and Medicine is a leading journal in the field of redox biology, which is the study of the role of reactive oxygen species (ROS) and other oxidizing agents in biological systems. The journal serves as a premier forum for publishing innovative and groundbreaking research that explores the redox biology of health and disease, covering a wide range of topics and disciplines. Free Radical Biology and Medicine also commissions Special Issues that highlight recent advances in both basic and clinical research, with a particular emphasis on the mechanisms underlying altered metabolism and redox signaling. These Special Issues aim to provide a focused platform for the latest research in the field, fostering collaboration and knowledge exchange among researchers and clinicians.