title: Metabolic study of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone to the enantiomers of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol in vitro in human bronchial epithelial cells using chiral capillary electrophoresis.
abstract: 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) with one chiral center at the carbinol is a major metabolite of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). As tobacco specific N-nitrosamines (TSNAs), NNK and NNAL are the most pulmonary carcinogens in tobacco products and smoke. In this paper, a chiral CE method modified with highly sulfated β-cyclodextrin (S-β-CD) was developed to investigate the stereoselective formation of NNAL from NNK in vitro in normal human bronchial epithelial (NHBE) cells. Combined with solid phase extraction (SPE) of the cell samples, NNK and NNAL enantiomers were baseline separated under the proposed CE conditions, with satisfactory recoveries (72.5-113% for NNK and (±)-NNAL) and low limits of detection (LOD, 2.5-3 μg/mL for NNK and (±)-NNAL). The cytotoxicity of NNK in NHBE cells was investigated through the cell counting kit (CCK) assay and proved to be highly dependent on the NNK's concentration. The metabolic results obtained from CE analysis demonstrated that NNK was preferentially metabolized to (+)-NNAL through carbonyl reduction. Meanwhile, the ratio of [(+)-NNAL]/[(-)-NNAL] was independent of NHBE cells' incubation time with NNK, but could be changed according to the original incubation concentration of NNK. This chiral CE method could be useful for the study on toxicology and metabolic transformations of related TSNAs.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Institute of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
authors.forename: Youyou
authors.initials: Y
authors.lastname: Yang
authors.forename: Cong
authors.initials: C
authors.lastname: Yu
authors.forename: Meng
authors.initials: M
authors.lastname: Zhou
authors.forename: Nannan
authors.initials: N
authors.lastname: Pang
authors.forename: Ning
authors.initials: N
authors.lastname: Li
authors.forename: Honggang
authors.initials: H
authors.lastname: Nie
authors.forename: Jie
authors.initials: J
authors.lastname: Liao
authors.forename: Yu
authors.initials: Y
authors.lastname: Bai
authors.forename: Huwei
authors.initials: H
authors.lastname: Liu
mesh_terms: D001980:Bronchi / Q000166:cytology / Q000378:metabolism*; D002478:Cells, Cultured; D019075:Electrophoresis, Capillary / Q000379:methods*; D004847:Epithelial Cells / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D009602:Nitrosamines / Q000032:analysis / Q000378:metabolism*; D011725:Pyridines / Q000032:analysis / Q000378:metabolism*; D015203:Reproducibility of Results; D020545:Respiratory Mucosa / Q000166:cytology / Q000378:metabolism*; D012680:Sensitivity and Specificity; D052616:Solid Phase Extraction; D013237:Stereoisomerism
chemical_list: D009602:Nitrosamines; D011725:Pyridines; C016583:4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone; C099565:4-(methylnitrosamino)-1-(3-pyridyl)-1-butan-1-ol