Braiden V, Nagayama Y, Iitaka M, Namba H, Niwa M, Yamashita S
Department of Nature Medicine, Atomic Bomb Disease Institute, Nagasaki University School of Medicine, Japan.
Endocrinology. 1998 Sep;139(9):3996-9. doi: 10.1210/endo.139.9.6286.
To develop gene therapy targeting thyroid carcinoma, the recombinant retrovirus (LNTGTK) carrying herpes simplex virus thymidine kinase (HSV-TK) gene under the control of thyroglobulin (TG) promoter was constructed and its efficacy was investigated in 3 thyroid cell lines; a differentiated normal rat thyroid cell line (FRTL5), malignant rat thyroid carcinoma cells derived from FRTL5 (FRTC) and a human anaplastic thyroid carcinoma cell line (FRO). TG mRNA was detected by Northern blot analysis in FRTL5 cells and by RT-PCR in FRTC cells when cultured with 2 U/L TSH and its expression levels were decreased by TSH withdrawal. However, either methods revealed no TG expression in FRO cells. In vitro cytotoxic assays demonstrated TG expression status-dependent cell killing by transduction of LNTGTK followed by ganciclovir (GCV) treatment. Thus, LNTGTK transduction increased the GCV sensitivity approximately 13,000- and approximately 160-folds in the presence of TSH and approximately 4- and approximately 27-folds in the absence of TSH in FRTL5 and FRTC cells, respectively. In contrast, there was no difference in the GCV cytotoxicity between parental and transduced FRO cells. Significant growth inhibition, but not complete eradication, of transduced FRTC cells was observed in in vivo subcutaneous tumor models of nude mice. These results demonstrate that retrovirus-mediated transduction of HSV-TK gene under the control of the TG promoter confers the GCV sensitivity selectively to TG-expressing thyroid cells. This system may therefore be feasible for gene therapy targeting TG-expressing thyroid carcinomas.
为了开发针对甲状腺癌的基因治疗方法，构建了携带在甲状腺球蛋白（TG）启动子控制下的单纯疱疹病毒胸苷激酶（HSV-TK）基因的重组逆转录病毒（LNTGTK），并在3种甲状腺细胞系中研究了其疗效；一种分化型正常大鼠甲状腺细胞系（FRTL5）、源自FRTL5的恶性大鼠甲状腺癌细胞（FRTC）和一种人未分化甲状腺癌细胞系（FRO）。当用2 U/L促甲状腺激素（TSH）培养时，通过Northern印迹分析在FRTL5细胞中检测到TG mRNA，通过逆转录聚合酶链反应（RT-PCR）在FRTC细胞中检测到TG mRNA，并且TSH撤除后其表达水平降低。然而，两种方法均未显示FRO细胞中有TG表达。体外细胞毒性试验表明，转导LNTGTK后再用更昔洛韦（GCV）处理，细胞杀伤具有TG表达状态依赖性。因此，在FRTL5和FRTC细胞中，LNTGTK转导分别在有TSH存在时使GCV敏感性增加约13000倍和约160倍，在无TSH存在时增加约4倍和约27倍。相比之下，亲本FRO细胞和转导后的FRO细胞在GCV细胞毒性方面没有差异。在裸鼠体内皮下肿瘤模型中观察到转导后的FRTC细胞有显著的生长抑制，但未完全根除。这些结果表明，在TG启动子控制下逆转录病毒介导的HSV-TK基因转导选择性地赋予表达TG的甲状腺细胞对GCV的敏感性。因此，该系统可能对靶向表达TG的甲状腺癌的基因治疗是可行的。
