Transcriptional activation of the thyroglobulin promoter directing suicide gene expression by thyroid transcription factor-1 in thyroid cancer cells.

Abstract

Gene therapy with thyroglobulin (TG) promoter and a prodrug/suicide gene combination may prove useful as a treatment for thyroid carcinoma. However, most poorly differentiated and anaplastic thyroid carcinomas have lost the ability to express the TG gene expression accompanied by loss of transcription factors [thyroid transcription factor-1 (TTF-1), TTF-2, or Pax-8] interacting with the TG promoter. In anticipation of developing transcriptionally targeted gene therapy of TG-nonproducing thyroid carcinomas, we investigated the effect of TTF-1 gene transfer on TG promoter activity and the cytotoxic effect obtained by the TG promoter-driven HSV-TK gene along with ganciclovir in thyroid carcinoma and nonthyroidal cells. Using a chimeric construct containing the 5'-flanking region of the rat TG gene between -826 and +39 bp and the luciferase gene, TG promoter activity was detected in a normal rat thyroid cell line (FRTL-5), but not in a dedifferentiated line of thyroid cells (FRT) expressing Pax-8 but not TTF-1, TTF-2, or TG [TTF-1(-)/TTF-2(-)/Pax-8(+)/TG(-)], or in a human papillary thyroid carcinoma cell line [BHP15-3; TTF-1(-)/TTF-2(-)/Pax-8(-)/TG(-)], a human pulmonary cell line [H441; TTF-1(+)/TTF-2(-)/Pax-8(-)/TG(-)], or a dog kidney epithelial cell line [MDCK; TTF-1(-)/TTF-2(-)/Pax-8(+)/TG(-)]. Cotransfection of the TTF-1 expression vector stimulated TG promoter activity in FRT and BHP15-3 dedifferentiated thyroid cells, but not in H441 pulmonary cells. Only weak activation was observed in MDCK kidney cells. We then constructed recombinant adenovirus vectors, AdTTF-1 and ADTGTK: AdTTF-1 contained cytomegalovirus promoter and rat TTF-1 cDNA; AdTGTK carried the TG promoter-driven HSV-TK gene. Infection with AdTGTK and combined with GCV treatment induced a cytotoxic effect in FRTL-5 cells but not in dedifferentiated thyroid or nonthyroid cells. Cotransduction of AdTTF-1 and AdTGTK permitted 90% cytotoxicity for BHP15-3 and >95% cytotoxicity for FRT, as well as for BHP7-13 and BHP18-21v thyroid cancer cell lines [both/TTF1(-)/TTF-2(-)/Pax-8(+)/TG(-)]. In contrast, little cytotoxicity was seen for H441 and MDCK cell lines even with 300 microg/ml of ganciclovir. These results suggest that cotransduction of a TG promoter-controlled suicide gene and the TTF-1 gene by adenoviral vectors confers transcriptionally targeted gene-mediated cytotoxicity in poorly differentiated thyroid carcinoma cells unable to express the TG gene.

• Authors: H Shimura, H Suzuki, A Miyazaki, F Furuya, K Ohta, K Haraguchi, T Endo, T Onaya
• Journal: Cancer research (Cancer Res) Vol. 61 Issue 9 Pg. 3640-6 (May 01 2001) ISSN: 0008-5472 [Print] United States
• PMID: 11325833 (Publication Type: Journal Article)

Chemical References

• NKX2-1 protein, human
• Nkx2-1 protein, rat
• Nuclear Proteins
• Thyroid Nuclear Factor 1
• Transcription Factors
• Thyroglobulin
• Thymidine Kinase
• Ganciclovir

Topics

• Adenoviridae (genetics)
• Animals
• Carcinoma, Papillary (drug therapy, genetics, therapy)
• Ganciclovir (pharmacokinetics, pharmacology)
• Gene Expression Regulation, Neoplastic
• Genetic Therapy (methods)
• Genetic Vectors (genetics)
• HeLa Cells
• Humans
• Nuclear Proteins (genetics)
• Promoter Regions, Genetic
• Rats
• Simplexvirus (enzymology, genetics)
• Thymidine Kinase (genetics, metabolism)
• Thyroglobulin (biosynthesis, genetics)
• Thyroid Neoplasms (drug therapy, genetics, therapy)
• Thyroid Nuclear Factor 1
• Transcription Factors (genetics)
• Transcriptional Activation
• Transduction, Genetic
• Tumor Cells, Cultured