Combined RNA Interference of Hexokinase II and 131 I-Sodium Iodide Symporter Gene Therapy for Anaplastic Thyroid Carcinoma

The purpose of this study was to investigate the enhanced therapeutic effect of the combined use of shRNA (small hairpin RNA) therapy for the hexokinase II (HKII) gene and 131 I human sodium iodide symporter (hNIS) as a gene therapy for in vitro and in vivo treatment of anaplastic thyroid carcinoma cells (ARO) in an animal model. Methods: A recombinant lentivirus containing a plasmid with the hNIS gene driven by phosphoglycerate kinase promoter and green fluorescent protein (GFP) linked with an internal ribosome entry site sequence was produced. ARO cells were transfected with the virus and sorted by fluorescent activated cell sorting using GFP (ARO-NG). The messenger RNA expression of hNIS and GFP were evaluated with reverse-transcriptase polymerase chain reaction, and the function of hNIS was verified by 125 I uptake. The lentiviral vector expressing shRNA against HKII (Lenti-HKII shRNA) was constructed and used to infect ARO-NG cells. The effect of LentiHKII shRNA was evaluated by reverse-transcriptase polymerase chain reaction, 18 F-FDG uptake, and HK activity. An in vitro clonogenic assay was performed after Lenti-HKII shRNA therapy, 131 I therapy, and a combined therapy. The therapies were also applied in vivo to an animal model with an ARO-NG xenograft, and the effects were assessed with caliper measurements and 18 F-FDG PET. Results: ARO-NG cells showed an 125 Iu ptake 76-fold higher than the parent ARO cells. Compared with the uninfected ARO-NG cells, ARO-NG cells infected with Lenti-HKII shRNA had lower HKII messenger RNA expression, lower 18 FFDG uptake, and HK activity. The proliferation of ARO-NG cells was inhibited by 131I and Lenti-HKII shRNA therapies and further inhibited by the combined 131 I and Lenti-HKII shRNA therapy. Both the Lenti-HKII shRNA therapy and the 131I therapy inhibited in vivo tumor growth in the tumor xenograft model. The combined Lenti-HKII shRNA and 131I therapy resulted in a further decrease of tumor growth. Conclusion: Our results suggest that the combined HKII shRNA and 131 I therapy has a stronger anti