title: Analysis of trichloroethylene-induced global DNA hypomethylation in hepatic L-02 cells by liquid chromatography-electrospray ionization tandem mass spectrometry.
abstract: Trichloroethylene (TCE), a major occupational and environmental pollutant, has been recently associated with aberrant epigenetic changes in experimental animals and cultured cells. TCE is known to cause severe hepatotoxicity; however, the association between epigenetic alterations and TCE-induced hepatotoxicity are not yet well explored. DNA methylation, catalyzed by enzymes known as DNA methyltransferases (DNMT), is a major epigenetic modification that plays a critical role in regulating many cellular processes. In this study, we analyzed the TCE-induced effect on global DNA methylation and DNMT enzymatic activity in human hepatic L-02 cells. A sensitive and quantitative method combined with liquid chromatography and electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) was validated and utilized for assessing the altered DNA methylation in TCE-induced L-02 cells. Quantification was accomplished in multiple reaction monitoring (MRM) mode by monitoring a transition pair of m/z 242.1 (molecular ion)/126.3 (fragment ion) for 5-mdC and m/z 268.1/152.3 for dG. The correlation coefficient of calibration curves between 5-mdC and dG was higher than 0.9990. The intra-day and inter-day relative standard derivation values (RSD) were on the range of 0.53-7.09% and 0.40-2.83%, respectively. We found that TCE exposure was able to significantly decrease the DNA methylation and inhibit DNMT activity in L-02 cells. Our results not only reveal the association between TCE exposure and epigenetic alterations, but also provide an alternative mass spectrometry-based method for rapid and accurate assessment of chemical-induced altered DNA methylation in mammal cells.
authors.affiliation: Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China; School of Life Science, Shenzhen University, Shenzhen 518060, China.
authors.forename: Hang
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China.
authors.forename: Wen-Xu
authors.initials: WX
authors.lastname: Hong
authors.affiliation: Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China.
authors.forename: Jinbo
authors.initials: J
authors.lastname: Ye
authors.affiliation: Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China.
authors.forename: Xifei
authors.initials: X
authors.lastname: Yang
authors.affiliation: Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China.
authors.forename: Xiaohu
authors.initials: X
authors.lastname: Ren
authors.affiliation: Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China.
authors.forename: Aibo
authors.initials: A
authors.lastname: Huang
authors.affiliation: Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China.
authors.forename: Linqing
authors.initials: L
authors.lastname: Yang
authors.affiliation: Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhou
authors.affiliation: Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Huang
authors.affiliation: Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China.
authors.forename: Desheng
authors.initials: D
authors.lastname: Wu
authors.affiliation: Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China.
authors.forename: Xinfeng
authors.initials: X
authors.lastname: Huang
authors.affiliation: Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China.
authors.forename: Zhixiong
authors.initials: Z
authors.lastname: Zhuang
authors.affiliation: Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China. Electronic address: bio-research@hotmail.com.
authors.forename: Jianjun
authors.initials: J
authors.lastname: Liu
mesh_terms: D002460:Cell Line; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004247:DNA / Q000187:drug effects* / Q000235:genetics*; D019175:DNA Methylation / Q000187:drug effects / Q000235:genetics*; D015254:DNA Modification Methylases / Q000378:metabolism*; D044127:Epigenesis, Genetic / Q000187:drug effects / Q000235:genetics*; D022781:Hepatocytes / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D009153:Mutagens / Q000633:toxicity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D014241:Trichloroethylene / Q000633:toxicity*
chemical_list: D009153:Mutagens; D014241:Trichloroethylene; D004247:DNA; D015254:DNA Modification Methylases
keywords: DNA methylation; DNA methyltrasferases (DNMT); Mass spectrometry (MS); Trichloroethylene (TCE)