title: Perfluorooctanoic acid induces gene promoter hypermethylation of glutathione-S-transferase Pi in human liver L02 cells.
abstract: Perfluorooctanoic acid (PFOA) is one of the most commonly used perfluorinated compounds. Being a persistent environmental pollutant, it can accumulate in human tissues via various exposure routes. PFOA may interfere in a toxic fashion on the immune system, liver, development, and endocrine systems. In utero human exposure had been associated with cord serum global DNA hypomethylation. In light of this, we investigated possible PFOA-induced DNA methylation alterations in L02 cells in order to shed light into its epigenetic-mediated mechanisms of toxicity in human liver. L02 cells were exposed to 5, 10, 25, 50 or 100 mg/L PFOA for 72h. Global DNA methylation levels were determined by LC/ESI-MS, glutathione-S-transferase Pi (GSTP) gene promoter DNA methylation was investigated by methylation-specific polymerase chain reaction (PCR) with bisulfite sequencing, and consequent mRNA expression levels were measured with quantitative real-time reverse transcriptase PCR. A dose-related increase of GSTP promoter methylation at the transcription factor specificity protein 1 (SP1) binding site was observed. However, PFOA did not significantly influence global DNA methylation; nor did it markedly alter the promoter gene methylation of p16 (cyclin-dependent kinase inhibitor 2A), ERα (estrogen receptor α) or PRB (progesterone receptor B). In addition, PFOA significantly elevated mRNA transcript levels of DNMT3A (which mediates de novo DNA methylation), Acox (lipid metabolism) and p16 (cell apoptosis). Considering the role of GSTP in detoxification, aberrant methylation may be pivotal in PFOA-mediated toxicity response via the inhibition of SP1 binding to GSTP promoter.
authors.affiliation: Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China.
authors.forename: Meiping
authors.initials: M
authors.lastname: Tian
authors.forename: Siyuan
authors.initials: S
authors.lastname: Peng
authors.forename: Francis L
authors.initials: FL
authors.lastname: Martin
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.forename: Liangpo
authors.initials: L
authors.lastname: Liu
authors.forename: Zhanlin
authors.initials: Z
authors.lastname: Wang
authors.forename: Sijun
authors.initials: S
authors.lastname: Dong
authors.forename: Heqing
authors.initials: H
authors.lastname: Shen
mesh_terms: D042962:Acyl-CoA Oxidase / Q000235:genetics; D002210:Caprylates / Q000633:toxicity*; D002460:Cell Line; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics; D019175:DNA Methylation; D000090205:DNA Methyltransferase 3A; D004785:Environmental Pollutants / Q000633:toxicity*; D047628:Estrogen Receptor alpha / Q000235:genetics; D005466:Fluorocarbons / Q000633:toxicity*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D051549:Glutathione S-Transferase pi / Q000235:genetics*; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D011401:Promoter Regions, Genetic / Q000187:drug effects; D012333:RNA, Messenger / Q000378:metabolism; D011980:Receptors, Progesterone / Q000235:genetics
chemical_list: D002210:Caprylates; D019941:Cyclin-Dependent Kinase Inhibitor p16; C000717967:DNMT3A protein, human; C506487:ESR1 protein, human; D004785:Environmental Pollutants; D047628:Estrogen Receptor alpha; D005466:Fluorocarbons; D012333:RNA, Messenger; D011980:Receptors, Progesterone; C097314:progesterone receptor B; C023036:perfluorooctanoic acid; D042962:Acyl-CoA Oxidase; D004248:DNA (Cytosine-5-)-Methyltransferases; D000090205:DNA Methyltransferase 3A; D051549:Glutathione S-Transferase pi