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

H. Shimura et al., Transcriptional activation of the thyroglobulin promoter directing suicidegene expression by thyroid transcription factor-1 in thyroid cancer cells, CANCER RES, 61(9), 2001, pp. 3640-3646
Citations number
Categorie Soggetti
Oncology,"Onconogenesis & Cancer Research
Journal title
ISSN journal
0008-5472 → ACNP
Year of publication
3640 - 3646
SICI code
Gene therapy with thyroglobulin (TG) promoter and a prodrug/suicide gene co mbination may prove useful as a treatment for thyroid carcinoma. However, m ost poorly differentiated and anaplastic thyroid carcinomas have lost the a bility to express the TG gene expression accompanied by loss of transcripti on factors [thyroid transcription factor-1 (TTF-1), TTF-2, or Pax-8] intera cting with the TG promoter. In anticipation of developing transcriptionally targeted gene therapy of TG-nonproducing thyroid carcinomas, we investigat ed the effect of TTF-1 gene transfer on TG promoter activity and the cytoto xic effect obtained by the TG promoter-driven HSV-TK gene along with gancic lovir in thyroid carcinoma and nonthyroidal cells. Using a chimeric constru ct containing the 5'-flanking region of the rat TG gene between -826 and +3 9 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 thyr oid 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 [H4 41; 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 expr ession vector stimulated TG promoter activity in FRT and BHP15-3 dedifferen tiated thyroid cells, but not in H441 pulmonary cells, Only weak activation was observed in MDCK kidney cells. We then constructed recombinant adenovi rus vectors, AdTTF-1 and AdTGTK, AdTTF-1 contained cytomegalovirus promoter and rat TTF-1 cDNA; AdTGTK carried the TG promoter-driven HSV-TK gene. Inf ection with AdTGTK and combined with GCV treatment induced a cytotoxic effe ct 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 thyro id 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 mug /ml of ganciclovir. These results suggest that cotransduction of a TG promo ter-controlled suicide gene and the TTF-1 gene by adenoviral vectors confer s transcriptionally targeted gene-mediated cytotoxicity in poorly different iated thyroid carcinoma cells unable to express the TG gene.