Identification of Adducts Produced by the Reaction of 4-(Acetoxymethylnitrosamino)-1-(3-pyridyl)-1-butanol with Deoxyguanosine and DNA
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- 作者：Pramod Upadhyaya ; Shana J. Sturla ; Natalia Tretyakova ; Rebecca Ziegel ; Peter W. Villalta ; Mingyao Wang ; and Stephen S. Hecht
- 刊名：Chemical Research in Toxicology
- 出版年：2003
- 出版时间：February 2003
- 年：2003
- 卷：16
- 期：2
- 页码：180 - 190
- 全文大小：235K
- 年卷期：v.16,no.2(February 2003)
- ISSN：1520-5010
文摘
4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) is a metabolite of the tobacco specificcarcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). NNAL is present in the bloodand urine of people exposed to tobacco products and has carcinogenic activity in rodents similarto that of NNK. DNA adducts specific to NNAL have not been previously identified. Metabolicactivation of NNAL by 
-methyl hydroxylation, a pathway known to occur in rodent and humanmicrosomes, would produce pyridylhydroxybutylating agents that could react with DNA. Weinvestigated this possibility in the present study by allowing 4-(acetoxymethylnitrosamino)-1-(3-pyridyl)-1-butanone (NNALCH2OAc) to react with dGuo and DNA. Products were identifiedby HPLC with UV detection, liquid chromatography/electrospray ionization-mass spectrometry(LC/ESI-MS) and LC/ESI-tandem mass spectrometry (LC/ESI-MS/MS). In the dGuo reactions,selected ion monitoring for m/z 417, corresponding to pyridylhydroxybutylated dGuo, showedseveral peaks. One adduct was identified as 7-[1-hydroxy-1-(3-pyridyl)but-4-yl]dGuo (21) byneutral thermal hydrolysis, which converted it to 7-[1-hydroxy-1-(3-pyridyl)but-4-yl]Gua (22)and 4-hydroxy-1-(3-pyridyl)-1-butanol (16). Adduct 22 was identified by comparison of its LC/ESI-MS and LC/ESI-MS/MS properties to those of standard 22. Two other adducts, O6-[1-hydroxy-1-(3-pyridyl)but-4-yl]dGuo (17) and N2-[1-hydroxy-1-(3-pyridyl)but-4-yl]dGuo (19), wereidentified by comparison of their LC/ESI-MS and LC/ESI-MS/MS properties to those of standard17 and 19. Further evidence for the identity of 17 and 19 was obtained by mild acid hydrolysis,which converted them to the corresponding Gua bases 18 and 20, identified by comparison tosynthetic standards. Neutral thermal hydrolysis of DNA that had been reacted with NNALCH2OAc produced 22, identified by comparison to a standard. Adducts 17 and 19 were identifiedin enzyme hydrolysates of this DNA by comparison to standards. Thus, DNA that had beenallowed to react with NNALCH2OAc contained adducts 17, 19, and 21. The results of thisstudy provide markers for investigating the role of specific NNAL-DNA adducts in carcinogenesis by NNAL and NNK.
-methyl hydroxylation, a pathway known to occur in rodent and humanmicrosomes, would produce pyridylhydroxybutylating agents that could react with DNA. Weinvestigated this possibility in the present study by allowing 4-(acetoxymethylnitrosamino)-1-(3-pyridyl)-1-butanone (NNALCH2OAc) to react with dGuo and DNA. Products were identifiedby HPLC with UV detection, liquid chromatography/electrospray ionization-mass spectrometry(LC/ESI-MS) and LC/ESI-tandem mass spectrometry (LC/ESI-MS/MS). In the dGuo reactions,selected ion monitoring for m/z 417, corresponding to pyridylhydroxybutylated dGuo, showedseveral peaks. One adduct was identified as 7-[1-hydroxy-1-(3-pyridyl)but-4-yl]dGuo (21) byneutral thermal hydrolysis, which converted it to 7-[1-hydroxy-1-(3-pyridyl)but-4-yl]Gua (22)and 4-hydroxy-1-(3-pyridyl)-1-butanol (16). Adduct 22 was identified by comparison of its LC/ESI-MS and LC/ESI-MS/MS properties to those of standard 22. Two other adducts, O6-[1-hydroxy-1-(3-pyridyl)but-4-yl]dGuo (17) and N2-[1-hydroxy-1-(3-pyridyl)but-4-yl]dGuo (19), wereidentified by comparison of their LC/ESI-MS and LC/ESI-MS/MS properties to those of standard17 and 19. Further evidence for the identity of 17 and 19 was obtained by mild acid hydrolysis,which converted them to the corresponding Gua bases 18 and 20, identified by comparison tosynthetic standards. Neutral thermal hydrolysis of DNA that had been reacted with NNALCH2OAc produced 22, identified by comparison to a standard. Adducts 17 and 19 were identifiedin enzyme hydrolysates of this DNA by comparison to standards. Thus, DNA that had beenallowed to react with NNALCH2OAc contained adducts 17, 19, and 21. The results of thisstudy provide markers for investigating the role of specific NNAL-DNA adducts in carcinogenesis by NNAL and NNK.