title: Effects of histone acetylation on sodium iodide symporter promoter and expression of thyroid-specific transcription factors.
abstract: Inhibitors of histone deacetylases (HDACs) activate the sodium iodide symporter (NIS) expression in thyroid tumor cells. In this study, mechanisms accounting for these effects were investigated. Various human thyroid tumor cell lines (ARO, BCPAP, FRO, TPC-1) were treated with the HDAC inhibitors Na butyrate (NaB) and tricostatin A (TSA), and the effects on the expression of NIS and several thyroid-specific transcription factors together with the activity of NIS promoter were evaluated. TSA and NaB increased NIS mRNA levels in all cell lines. Among thyroid-specific transcription factors, only expression of PAX8 in ARO cells was increased. Down-regulation of thyroid-specific transcription factor-1 expression was observed in BCPAP and TPC-1 cell lines. Thyroid-specific transcription factor-2 mRNA was reduced in FRO, BCPAP, and TPC-1 cells. Histone acetylation had no significant effects on HEX expression. Altogether, these data indicate that the increase of NIS expression is not mediated by modification of expression of thyroid-specific transcription factors. Accordingly, in transfection experiments performed in the HeLa cell line (which does not express thyroid-specific transcription factors), treatment with TSA and NaB increased NIS promoter activity. Stimulation of NIS promoter activity was also obtained by overexpressing histone acetylating proteins pCAF and p300 in HeLa cells. Conversely, overexpression of the HDAC 1 enzyme inhibited basal activity of the NIS promoter. Effects of TSA and NaB on NIS expression were also evaluated in nonthyroid cell lines MCF-7, Hep-G2, and SAOS-2. In all cell lines TSA and NaB greatly increased NIS mRNA levels. We concluded that control of NIS expression by inhibition of HDAC appears not to be mediated by cell-specific mechanisms, suggesting it as a potential strategy to induce radioiodine sensitivity in different human tumors.
authors.affiliation: Dipartimento di Scienze e Tecnologie Biomediche, Policlinico Universitario di Udine, Piazzale Kolbe 1, 33100 Udine, Italy.
authors.forename: Cinzia
authors.initials: C
authors.lastname: Puppin
authors.forename: Federica
authors.initials: F
authors.lastname: D'Aurizio
authors.forename: Angela V
authors.initials: AV
authors.lastname: D'Elia
authors.forename: Laura
authors.initials: L
authors.lastname: Cesaratto
authors.forename: Gianluca
authors.initials: G
authors.lastname: Tell
authors.forename: Diego
authors.initials: D
authors.lastname: Russo
authors.forename: Sebastiano
authors.initials: S
authors.lastname: Filetti
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Ferretti
authors.forename: Emanuele
authors.initials: E
authors.lastname: Tosi
authors.forename: Tiziana
authors.initials: T
authors.lastname: Mattei
authors.forename: Annalisa
authors.initials: A
authors.lastname: Pianta
authors.forename: Lucia
authors.initials: L
authors.lastname: Pellizzari
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Damante
mesh_terms: D000107:Acetylation; D001943:Breast Neoplasms; D006528:Carcinoma, Hepatocellular; D045744:Cell Line, Tumor; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015870:Gene Expression / Q000502:physiology; D015972:Gene Expression Regulation, Neoplastic; D056572:Histone Deacetylase Inhibitors; D006655:Histone Deacetylases / Q000378:metabolism; D006657:Histones / Q000378:metabolism*; D006801:Humans; D008113:Liver Neoplasms; D012516:Osteosarcoma; D011401:Promoter Regions, Genetic / Q000502:physiology; D027981:Symporters / Q000235:genetics*; D013964:Thyroid Neoplasms / Q000235:genetics* / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D000099209:Sodium-Iodide Symporters
chemical_list: D004791:Enzyme Inhibitors; D056572:Histone Deacetylase Inhibitors; D006655:Histone Deacetylases; D006657:Histones; D027981:Symporters; D014157:Transcription Factors; D000099209:Sodium-Iodide Symporters