title: Effects of nickel treatment on H3K4 trimethylation and gene expression.
abstract: Occupational exposure to nickel compounds has been associated with lung and nasal cancers. We have previously shown that exposure of the human lung adenocarcinoma A549 cells to NiCl(2) for 24 hr significantly increased global levels of trimethylated H3K4 (H3K4me3), a transcriptional activating mark that maps to the promoters of transcribed genes. To further understand the potential epigenetic mechanism(s) underlying nickel carcinogenesis, we performed genome-wide mapping of H3K4me3 by chromatin immunoprecipitation and direct genome sequencing (ChIP-seq) and correlated with transcriptome genome-wide mapping of RNA transcripts by massive parallel sequencing of cDNA (RNA-seq). The effect of NiCl(2) treatment on H3K4me3 peaks within 5,000 bp of transcription start sites (TSSs) on a set of genes highly induced by nickel in both A549 cells and human peripheral blood mononuclear cells were analyzed. Nickel exposure increased the level of H3K4 trimethylation in both the promoters and coding regions of several genes including CA9 and NDRG1 that were increased in expression in A549 cells. We have also compared the extent of the H3K4 trimethylation in the absence and presence of formaldehyde crosslinking and observed that crosslinking of chromatin was required to observe H3K4 trimethylation in the coding regions immediately downstream of TSSs of some nickel-induced genes including ADM and IGFBP3. This is the first genome-wide mapping of trimethylated H3K4 in the promoter and coding regions of genes induced after exposure to NiCl(2). This study may provide insights into the epigenetic mechanism(s) underlying the carcinogenicity of nickel compounds.
authors: Department of Environmental Medicine, New York University School of Medicine, Tuxedo, New York, United States of America. tchouk02@nyumc.org
authors: Kam-Meng
authors: KM
authors: Tchou-Wong
authors: Kathrin
authors: K
authors: Kiok
authors: Zuojian
authors: Z
authors: Tang
authors: Thomas
authors: T
authors: Kluz
authors: Adriana
authors: A
authors: Arita
authors: Phillip R
authors: PR
authors: Smith
authors: Stuart
authors: S
authors: Brown
authors: Max
authors: M
authors: Costa
mesh_terms: D000951:Antigens, Neoplasm / Q000235:genetics; D000071231:Carbonic Anhydrase IX; D002256:Carbonic Anhydrases / Q000235:genetics; D018797:Cell Cycle Proteins / Q000235:genetics; D045744:Cell Line, Tumor; D019175:DNA Methylation / Q000187:drug effects* / Q000235:genetics*; D044127:Epigenesis, Genetic / Q000187:drug effects* / Q000235:genetics; D006657:Histones / Q000187:drug effects* / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics; D009532:Nickel / Q000494:pharmacology*; D000099259:N-myc Downstream-Regulated Gene 1 Protein
chemical_list: D000951:Antigens, Neoplasm; D000071231:Carbonic Anhydrase IX; D002256:Carbonic Anhydrases; D018797:Cell Cycle Proteins; D006657:Histones; D047908:Intracellular Signaling Peptides and Proteins; D009532:Nickel; D000099259:N-myc Downstream-Regulated Gene 1 Protein; C089226:CA9 protein, human