title: Overexpression of TTF-1 and PAX-8 restores thyroglobulin gene promoter activity in ARO and WRO cell lines.
abstract: BACKGROUND
  In anticipation of developing gene therapy against thyroid carcinoma we created an expression vector using the thyroglobulin (Tg) gene promoter. The inhibition of both Tg and thyroid-specific transcription factor (TTF-1 and PAX-8) gene expression, however, has been well documented in thyroid carcinomas. We therefore examined the effects of overexpression of TTF-1 and PAX-8 on Tg gene promoter activity in the human thyroid carcinoma cell lines, ARO (anaplastic) and WRO (follicular).
  
  
  METHODS
  ARO, WRO, and nonthyroid cells were transfected with an expression vector in which beta-galactosidase (beta-gal) is driven by the Tg gene promoter (beta-gal). Tg, TTF-1, and PAX-8 gene expression were also examined by reverse transcriptase-polymerase chain reaction (RT-PCR).
  
  
  RESULTS
  ARO and WRO exhibited decreased gene expression of Tg, TTF-1, and PAX-8. Transfection with TG--gal alone exhibited minimal beta-gal expression, whereas cotransfection with TTF-1 and PAX-8 resulted in markedly increased expression. There was no evidence of beta-gal expression with or without TTF-1 and PAX-8 in nonthyroid cells.
  
  
  CONCLUSIONS
  Weak Tg gene promoter activity in ARO and WRO is associated with decreased expression of transcription factors TTF-1 and PAX-8 but can be restored with their overexpression. This model may serve as a template on which to further develop cell-specific gene therapy against thyroid carcinoma.
authors.affiliation: Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Md., USA.
authors.forename: Y S
authors.initials: YS
authors.lastname: Chun
authors.forename: M
authors.initials: M
authors.lastname: Saji
authors.forename: M A
authors.initials: MA
authors.lastname: Zeiger
mesh_terms: D004268:DNA-Binding Proteins / Q000235:genetics*; D006801:Humans; D009687:Nuclear Proteins / Q000235:genetics*; D000072636:PAX8 Transcription Factor; D051761:Paired Box Transcription Factors; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis; D013954:Thyroglobulin / Q000235:genetics*; D013961:Thyroid Gland; D013964:Thyroid Neoplasms / Q000235:genetics*; D000074482:Thyroid Nuclear Factor 1; D015534:Trans-Activators / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D004268:DNA-Binding Proteins; C000614412:NKX2-1 protein, human; D009687:Nuclear Proteins; D000072636:PAX8 Transcription Factor; C083325:PAX8 protein, human; D051761:Paired Box Transcription Factors; D012333:RNA, Messenger; D000074482:Thyroid Nuclear Factor 1; D015534:Trans-Activators; D014157:Transcription Factors; D013954:Thyroglobulin