The Human Norepinephrine Transporter in Combination with 11C-m-Hydroxyephedrine as a Reporter Gene/Reporter Probe for PET of Gene Therapy

Journal of Nuclear Medicine

Willem Vaalburg¹  Erik F.J. de Vries¹  Hidde J. Haisma¹  Marianne G. Rots¹  Aren van Waarde¹  Geke A.P. Hospers¹  Anne Rixt Buursma¹  Antoine M.J. Beerens¹ 

关键词: ¹¹C-m-hydroxyephedrine;    human norepinephrine transporter;    PET;    gene therapy;    reporter gene;   

DOI  :  

学科分类：医学（综合）

来源: Society of Nuclear Medicine

【 摘 要 】

Although the herpes simplex virus thymidine kinase gene has been frequently applied as a reporter gene for monitoring gene transfection in animals, it has some intrinsic limitations for use in humans. In our search for a reporter gene that lacks these limitations, we have evaluated the feasibility of the human norepinephrine transporter (hNET) as a reporter gene in combination with the reporter probe 11C-m-hydroxyephedrine (mHED) for PET. Methods: An adenoviral vector (AdTrack-hNET) containing the hNET gene as reporter gene and the enhanced green fluorescent protein (EGFP) as a substitute for a therapeutic gene was constructed. After COS-7, A2780, and U373 cells were transiently transduced with AdTrack-hNET, hNET protein expression, EGFP fluorescence, and cellular uptake of 11C-mHED were determined. In rats, U373 tumor xenografts were grown and transiently transduced with either AdTrack-hNET or an AdTrack-Luc control adenovirus. Intratumoral accumulation of 11C-mHED was determined by PET and ex vivo biodistribution. The tumors were subsequently examined for EGFP fluorescence. Results: 11C-mHED uptake was positively correlated with AdTrack-hNET viral titer and hNET protein expression. However, large differences in transfection efficiency between cell lines were observed. The highest 11C-mHED uptake was found in hNET transfected U373 cells, in which tracer uptake was >70-fold higher than that in control cells. 11C-mHED accumulation could be inhibited by desipramine, a potent inhibitor of hNET. In all cell lines, 11C-mHED uptake was positively correlated with EGFP fluorescence, implying that imaging of hNET with 11C-mHED would enable monitoring of a coexpressed therapeutic gene. In the animal model, gene transfection efficiencies were very low, as determined by EGFP fluorescence. Still, a significantly higher 11C-mHED uptake in hNET transduced tumors than that in control tumors was demonstrated by ex vivo biodistribution studies. PET with a clinical camera could visualize 1 of 3 hNET transduced tumors, indicating that the transfection efficiency was near the detection limit. Conclusion: These results indicate that monitoring of gene therapy using the hNET/11C-mHED reporter gene/probe is feasible, but further investigation with regard to the sensitivity of the technique is required.

【 授权许可】

Unknown