Dynamic transcriptional regulatory complexes including BORIS, CTCF and Sp1 modulate NY-ESO-1 expression in lung cancer cells.
Previously, we reported that the paralogous zinc-finger proteins--CTCF and brother of the regulator of imprinted sites (BORIS), directly contribute to transcriptional regulation of NY-ESO-1 in lung cancer cells. To further examine mechanisms that mediate expression of this cancer-testis gene, we performed software-guided analysis of the NY-ESO-1 promoter region, which revealed several potential Sp1-binding motifs. Sequential 5-aza-2'deoxycytidine/depsipeptide FK228 treatment markedly induced BORIS expression and enhanced nuclear translocation of Sp1 in lung cancer cells. Transient transfection assays using promoter-reporter constructs, as well as gel-shift and chromatin immunoprecipitation experiments revealed that NY-ESO-1 promoter activity coincided with occupancy of the proximal Sp1-binding site in lung cancer cells. Mutations within the Sp1 recognition sequence specifically eliminated binding of Sp1 to this motif in vitro, and markedly diminished NY-ESO-1 promoter activity in vivo. siRNA-mediated inhibition of Sp1 expression decreased NY-ESO-1 promoter activity, whereas knock down of CTCF expression augmented NY-ESO-1 transcription in lung cancer cells. Co-immunoprecipitation experiments indicated that Sp1 physically interacts with BORIS but not with CTCF in vivo. Collectively, these findings suggest that BORIS recruits Sp1 to mediate de-repression of NY-ESO-1 during pulmonary carcinogenesis.
Kang
Y
Y
Thoracic Oncology Section, Surgery Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892-1201, USA.
Hong
J A
JA
Chen
G A
GA
Nguyen
D M
DM
Schrump
D S
DS
D000951:Antigens, Neoplasm / Q000032:analysis / Q000235:genetics*; D001483:Base Sequence; D001665:Binding Sites; D000076246:CCCTC-Binding Factor; D045744:Cell Line, Tumor; D004268:DNA-Binding Proteins / Q000502:physiology*; D047630:Depsipeptides / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism*; D008565:Membrane Proteins / Q000032:analysis / Q000235:genetics*; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000502:physiology*; D016329:Sp1 Transcription Factor / Q000502:physiology*
D000951:Antigens, Neoplasm; D000076246:CCCTC-Binding Factor; C104948:CTAG1B protein, human; C000619697:CTCF protein, human; C456540:CTCFL protein, human; D004268:DNA-Binding Proteins; D047630:Depsipeptides; D008565:Membrane Proteins; D012097:Repressor Proteins; D016329:Sp1 Transcription Factor