Hypoxia and nickel inhibit histone demethylase JMJD1A and repress Spry2 expression in human bronchial epithelial BEAS-2B cells.
Epigenetic silencing of tumor suppressor genes commonly occurs in human cancers via increasing DNA methylation and repressive histone modifications at gene promoters. However, little is known about how pathogenic environmental factors contribute to cancer development by affecting epigenetic regulatory mechanisms. Previously, we reported that both hypoxia and nickel (an environmental carcinogen) increased global histone H3 lysine 9 methylation in cells through inhibiting a novel class of iron- and α-ketoglutarate-dependent histone demethylases. Here, we investigated whether inhibition of histone demethylase JMJD1A by hypoxia and nickel could lead to repression/silencing of JMJD1A-targeted gene(s). By using Affymetrix GeneChip and ChIP-on-chip technologies, we identified Spry2 gene, a key regulator of receptor tyrosine kinase/extracellular signal-regulated kinase (ERK) signaling, as one of the JMJD1A-targeted genes in human bronchial epithelial BEAS-2B cells. Both hypoxia and nickel exposure increased the level of H3K9me2 at the Spry2 promoter by inhibiting JMJD1A, which probably led to a decreased expression of Spry2 in BEAS-2B cells. Repression of Spry2 potentiated the nickel-induced ERK phosphorylation, and forced expression of Spry2 in BEAS-2B cells decreased the nickel-induced ERK phosphorylation and significantly suppressed nickel-induced anchorage-independent growth. Taken together, our results suggest that histone demethylases could be targets of environmental carcinogens and their inhibition may lead to altered gene expression and eventually carcinogenesis.
Chen
Haobin
H
Department of Environmental Medicine, New York University of School of Medicine, 550 First Avenue, New York, NY 10016, USA. haobin.chen@nyumc.org
Kluz
Thomas
T
Zhang
Ronghe
R
Costa
Max
M
D000818:Animals; D001980:Bronchi / Q000187:drug effects / Q000378:metabolism*; D001984:Bronchial Neoplasms / Q000209:etiology; D002274:Carcinogens, Environmental / Q000633:toxicity*; D015687:Cell Hypoxia; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D015536:Down-Regulation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000502:physiology; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors / Q000235:genetics*; D056484:Jumonji Domain-Containing Histone Demethylases / Q000037:antagonists & inhibitors* / Q000502:physiology; D008565:Membrane Proteins; D051379:Mice; D009532:Nickel / Q000633:toxicity*; D020545:Respiratory Mucosa / Q000166:cytology / Q000187:drug effects / Q000378:metabolism
D002274:Carcinogens, Environmental; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C485561:SPRY2 protein, human; D009532:Nickel; D056484:Jumonji Domain-Containing Histone Demethylases; C530247:KDM3A protein, human; D048049:Extracellular Signal-Regulated MAP Kinases