title: DNA methylation and histone modifications modulate the β1,3 galactosyltransferase β3Gal-T5 native promoter in cancer cells.
abstract: The native promoter of β1,3 galactosyltransferase β3Gal-T5 contributes to the expression of the enzyme and its oligosaccharide products, such as Lewis antigens, in many tissues. It is mainly sensitive to nuclear factor NF-Y and located nearby two CpG islands. To elucidate the regulation of the native promoter, we analyzed NF-Y protein and β3Gal-T5 mRNA, and found that NF-Y is scarcely modulated among various cell lines and biopsies from normal or cancerous colon. Conversely, β3Gal-T5 expression levels vary in the cell lines and are strongly down-regulated in colon cancer. We also performed quantitative methylation analysis of β3Gal-T5 CpG islands and found an inverse correlation between mRNA expression and DNA methylation. In particular, the methylation levels of both islands are always increased in cancer, with respect to the corresponding normal counterpart, in matched normal and tumor samples of colon and breast origin. Moreover, treatment with chromatin remodeling agents 5-aza-2'deoxycytidine and trichostatin A does not restore transcription in completely negative cells, but only increases expression in basally positive cells. However, methylation analysis after 5-aza-2'deoxycytidine treatment revealed partial demethylation of both islands in all treated cells. Finally, chromatin immunoprecipitation assays on β3Gal-T5 promoter showed that histone H3K4 trymethylation, H3K79 dimethylation, and H3K9-14 acetylation are high in cells expressing the transcript, and very low in those negative, while H4K20 trimethylation and H3K27 dimethylation are the opposite. We conclude that complex epigenetic modulation underlies the regulation of β3Gal-T5 native promoter.
authors: Department of Medicine, Surgery and Dentistry, San Paolo Hospital, Università degli Studi di Milano, Milan, Italy.
authors: Anna
authors: A
authors: Caretti
authors: Silvia M
authors: SM
authors: Sirchia
authors: Silvia
authors: S
authors: Tabano
authors: Aida
authors: A
authors: Zulueta
authors: Fabio
authors: F
authors: Dall'Olio
authors: Marco
authors: M
authors: Trinchera
mesh_terms: D023081:CCAAT-Binding Factor / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D047369:Chromatin Immunoprecipitation; D019175:DNA Methylation; D015536:Down-Regulation; D005700:Galactosyltransferases / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D006657:Histones / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D009369:Neoplasms / Q000201:enzymology* / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D011401:Promoter Regions, Genetic
chemical_list: D023081:CCAAT-Binding Factor; D006657:Histones; C479886:B3GALT5 protein, human; D005700:Galactosyltransferases