Abstract
1434
Objectives: We investigated the feasibility of gene therapy and molecular imaging in α-fetoprotein (AFP) producing hepatocellular carcinoma (HCC) following tumor-specific expression of the human sodium iodide symporter (hNIS) using an AFP enhancer/promoter. Methods: The recombinant plasmid containing human AFP enhancer/promoter to direct the tissue-specific expression of hNIS gene was constructed and designated as pcDNA3-AFP/hNIS. The pcDNA3-AFP/hNIS was stably transfected to AFP-producing human HCC cells (Huh-7;Huh-7/AN) and AFP-non producing rat glioma cells (C6;C6/AN) using lipofectamine plus reagent. Functional hNIS expression was confirmed by iodide uptake and the mRNA and protein expression level of hNIS were measured by RT-PCR and western blot analysis in Huh-7/AN and C6/AN cells, respectively. Biodistribution was evaluated at 0.5, 1, 6 and 24 h after injection of I-131 and scintigraphic images of Tc-99m were obtained with a gamma-camera in tumor bearing mice. Clonogenic assay was performed to confirm whether Huh-7/AN and C6/AN can be selectively killed by I-131. Results: The hNIS gene was successfully expressed in Huh-7/AN cells. In Huh-7/AN cells, iodine uptake was 18 and 150 times higher than C6/AN cells and Huh-7 cells, respectively, and completely blocked by perchlorate. The increased mRNA expression of hNIS was shown in Huh-7/AN cells, compared with that of C6/AN cells. The protein level analyzed by western blotting was correlated with mRNA expression level. Radioiodine uptake in Huh-7/AN xenografted tumors was higher than those in Huh-7 and C6 tumors, and the Huh-7/AN tumor was clearly visualized in whole-body scintigraphic images. The survival rate was significantly decreased in Huh-7/AN cells (43.22±1.58%) by I-131. Conclusions: AFP-producing hepatocelluar carcinoma was targeted with hNIS gene using AFP enhancer/promoter. This targeted hNIS gene therapy and molecular imaging have the potential to be used in the management of AFP-producing HCC.
- Society of Nuclear Medicine, Inc.