Willhauck M J, Sharif Samani B R, Klutz K, Cengic N, Wolf I, Mohr L, Geissler M, Senekowitsch-Schmidtke R, Göke B, Morris J C, Spitzweg C
Department of Internal Medicine II, Ludwig-Maximilians-University, Munich, Germany.
Gene Ther. 2008 Feb;15(3):214-23. doi: 10.1038/sj.gt.3303057. Epub 2007 Nov 8.
Due to limited treatment options the prognosis of patients with advanced hepatocellular cancer (HCC) has remained poor. To investigate an alternative therapeutic approach, we examined the feasibility of radioiodine therapy of HCC following human sodium iodide symporter (NIS) gene transfer using a mouse alpha-fetoprotein (AFP) promoter construct to target NIS expression to HCC cells. For this purpose, the murine Hepa 1-6 and the human HepG2 hepatoma cell lines were stably transfected with NIS cDNA under the control of the tumor-specific AFP promoter. The stably transfected Hepa 1-6 cell line showed a 10-fold increase in iodide accumulation, while HepG2 cells accumulated (125)I approximately 60-fold. Tumor-specific NIS expression was confirmed on mRNA level by northern blot analysis, and on protein level by immunostaining, that revealed primarily membrane-associated NIS-specific immunoreactivity. In an in vitro clonogenic assay up to 78% of NIS-transfected Hepa 1-6 and 93% of HepG2 cells were killed by (131)I exposure, while up to 96% of control cells survived. In vivo NIS-transfected HepG2 xenografts accumulated 15% of the total (123)I administered per gram tumor with a biological half-life of 8.38 h, resulting in a tumor absorbed dose of 171 mGy MBq(-1) (131)I. After administration of a therapeutic (131)I dose (55.5 MBq) tumor growth of NIS expressing HepG2 xenografts was significantly inhibited. In conclusion, tumor-specific iodide accumulation was induced in HCC cells by AFP promoter-directed NIS expression in vitro and in vivo, which was sufficiently high to allow a therapeutic effect of (131)I. This study demonstrates the potential of tumor-specific NIS gene therapy as an innovative treatment strategy for HCC.
由于治疗选择有限，晚期肝细胞癌（HCC）患者的预后仍然很差。为了研究一种替代治疗方法，我们使用小鼠甲胎蛋白（AFP）启动子构建体将人碘化钠同向转运体（NIS）基因转移至HCC细胞后，检测了HCC放射性碘治疗的可行性，该构建体可将NIS表达靶向至HCC细胞。为此，将鼠Hepa 1-6和人HepG2肝癌细胞系在肿瘤特异性AFP启动子的控制下稳定转染NIS cDNA。稳定转染的Hepa 1-6细胞系碘摄取增加了10倍，而HepG2细胞积累的（125）I约为60倍。通过Northern印迹分析在mRNA水平以及通过免疫染色在蛋白质水平证实了肿瘤特异性NIS表达，免疫染色显示主要为膜相关的NIS特异性免疫反应性。在体外克隆形成试验中，高达78%的NIS转染Hepa 1-6细胞和93%的HepG2细胞在暴露于（131）I后被杀死，而高达96%的对照细胞存活。在体内，NIS转染的HepG2异种移植瘤每克肿瘤积累了所给予总（123）I的15%，生物半衰期为8.38小时，导致肿瘤吸收剂量为171 mGy MBq（-1）（131）I。给予治疗剂量的（131）I（55.5 MBq）后，表达NIS的HepG2异种移植瘤的肿瘤生长受到显著抑制。总之，通过AFP启动子导向的NIS表达在体外和体内均可诱导HCC细胞中肿瘤特异性碘摄取，其足够高以实现（131）I的治疗效果。本研究证明了肿瘤特异性NIS基因治疗作为HCC创新治疗策略的潜力。
