Chun Y S, Saji M, Zeiger M A
Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Md., USA.
Surgery. 1998 Dec;124(6):1100-5. doi: 10.1067/msy.1998.92008.
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).
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).
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.
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.
为了开发针对甲状腺癌的基因治疗方法，我们利用甲状腺球蛋白（Tg）基因启动子构建了一个表达载体。然而，在甲状腺癌中，Tg以及甲状腺特异性转录因子（TTF-1和PAX-8）基因表达的抑制已有充分记录。因此，我们检测了在人甲状腺癌细胞系ARO（间变性）和WRO（滤泡性）中过表达TTF-1和PAX-8对Tg基因启动子活性的影响。
用一个表达载体转染ARO、WRO和非甲状腺细胞，该表达载体中β-半乳糖苷酶（β-gal）由Tg基因启动子驱动（β-gal）。还通过逆转录聚合酶链反应（RT-PCR）检测Tg、TTF-1和PAX-8基因表达。
ARO和WRO中Tg、TTF-1和PAX-8的基因表达降低。单独转染TG-β-gal时β-gal表达极少，而与TTF-1和PAX-8共转染则导致表达显著增加。在非甲状腺细胞中，无论有无TTF-1和PAX-8，均未检测到β-gal表达。
ARO和WRO中较弱的Tg基因启动子活性与转录因子TTF-1和PAX-8表达降低有关，但过表达这些转录因子可使其恢复。该模型可作为进一步开发针对甲状腺癌的细胞特异性基因治疗的模板。
