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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
17
pubmed:dateCreated
2005-9-5
pubmed:abstractText
Regulatory sequences recognized by the unique pair of paralogous factors, CTCF and BORIS, have been implicated in epigenetic regulation of imprinting and X chromosome inactivation. Lung cancers exhibit genome-wide demethylation associated with derepression of a specific class of genes encoding cancer-testis (CT) antigens such as NY-ESO-1. CT genes are normally expressed in BORIS-positive male germ cells deficient in CTCF and meCpG contents, but are strictly silenced in somatic cells. The present study was undertaken to ascertain if aberrant activation of BORIS contributes to derepression of NY-ESO-1 during pulmonary carcinogenesis. Preliminary experiments indicated that NY-ESO-1 expression coincided with derepression of BORIS in cultured lung cancer cells. Quantitative reverse transcription-PCR analysis revealed robust, coincident induction of BORIS and NY-ESO-1 expression in lung cancer cells, but not normal human bronchial epithelial cells following 5-aza-2'-deoxycytidine (5-azadC), Depsipeptide FK228 (DP), or sequential 5-azadC/DP exposure under clinically relevant conditions. Bisulfite sequencing, methylation-specific PCR, and chromatin immunoprecipitation (ChIP) experiments showed that induction of BORIS coincided with direct modulation of chromatin structure within a CpG island in the 5'-flanking noncoding region of this gene. Cotransfection experiments using promoter-reporter constructs confirmed that BORIS modulates NY-ESO-1 expression in lung cancer cells. Gel shift and ChIP experiments revealed a novel CTCF/BORIS-binding site in the NY-ESO-1 promoter, which unlike such sites in the H19-imprinting control region and X chromosome, is insensitive to CpG methylation in vitro. In vivo occupancy of this site by CTCF was associated with silencing of the NY-ESO-1 promoter, whereas switching from CTCF to BORIS occupancy coincided with derepression of NY-ESO-1. Collectively, these data indicate that reciprocal binding of CTCF and BORIS to the NY-ESO-1 promoter mediates epigenetic regulation of this CT gene in lung cancer cells, and suggest that induction of BORIS may be a novel strategy to augment immunogenicity of pulmonary carcinomas.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0008-5472
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
65
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7763-74
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed-meshheading:16140944-Antigens, Neoplasm, pubmed-meshheading:16140944-Base Sequence, pubmed-meshheading:16140944-Cell Line, Tumor, pubmed-meshheading:16140944-Chromatin Immunoprecipitation, pubmed-meshheading:16140944-DNA Methylation, pubmed-meshheading:16140944-DNA-Binding Proteins, pubmed-meshheading:16140944-Gene Expression Regulation, Neoplastic, pubmed-meshheading:16140944-Gene Silencing, pubmed-meshheading:16140944-Histones, pubmed-meshheading:16140944-Humans, pubmed-meshheading:16140944-Immunohistochemistry, pubmed-meshheading:16140944-Lung Neoplasms, pubmed-meshheading:16140944-Membrane Proteins, pubmed-meshheading:16140944-Molecular Sequence Data, pubmed-meshheading:16140944-Polymerase Chain Reaction, pubmed-meshheading:16140944-Promoter Regions, Genetic, pubmed-meshheading:16140944-Protein Binding, pubmed-meshheading:16140944-Repressor Proteins, pubmed-meshheading:16140944-Reverse Transcriptase Polymerase Chain Reaction, pubmed-meshheading:16140944-Sulfites
pubmed:year
2005
pubmed:articleTitle
Reciprocal binding of CTCF and BORIS to the NY-ESO-1 promoter coincides with derepression of this cancer-testis gene in lung cancer cells.
pubmed:affiliation
Thoracic Oncology Section, Surgery Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892-1201, USA.
pubmed:publicationType
Journal Article