Systemic Image-Guided Liver Cancer Radiovirotherapy Using Dendrimer-Coated Adenovirus Encoding the Sodium Iodide Symporter as Theranostic Gene

Journal of Nuclear Medicine

Burkhard Göke¹  Reingard Senekowitsch-Schmidtke¹  Manfred Ogris¹  Ernst Wagner¹  Per S. Holm¹  Markus Schwaiger¹  Christine Spitzweg¹  Nathalie Schwenk¹  Alexandra Vetter¹  Geoffrey K. Grünwald¹  Christian Zach¹  Michael J. Willhauck¹  Kathrin Klutz¹ 

关键词: adenovirus serotype 5;    PAMAM dendrimer;    sodium iodide symporter (NIS);    radiovirotherapy;    gene therapy;   

DOI  :  10.2967/jnumed.112.115493

学科分类：医学（综合）

来源: Society of Nuclear Medicine

【 摘 要 】

Currently, major limitations for the clinical application of adenovirus-mediated gene therapy are high prevalence of neutralizing antibodies, widespread expression of the coxsackie-adenovirus receptor (CAR), and adenovirus sequestration by the liver. In the current study, we used the sodium iodide symporter (NIS) as a theranostic gene to investigate whether coating of adenovirus with synthetic dendrimers could be useful to overcome these hurdles in order to develop adenoviral vectors for combination of systemic oncolytic virotherapy and NIS-mediated radiotherapy. Methods: We coated replication-deficient (Ad5-CMV/NIS) (CMV is cytomegalovirus) and replication-selective (Ad5-E1/AFP-E3/NIS) adenovirus serotype 5 carrying the hNIS gene with poly(amidoamine) dendrimers generation 5 (PAMAM-G5) in order to investigate transduction efficacy and altered tropism of these coated virus particles by 123I scintigraphy and to evaluate their therapeutic potential for systemic radiovirotherapy in a liver cancer xenograft mouse model. Results: After dendrimer coating, Ad5-CMV/NIS demonstrated partial protection from neutralizing antibodies and enhanced transduction efficacy in CAR-negative cells in vitro. In vivo 123I scintigraphy of nude mice revealed significantly reduced levels of hepatic transgene expression after intravenous injection of dendrimer-coated Ad5-CMV/NIS (dcAd5-CMV/NIS). Evasion from liver accumulation resulted in significantly reduced liver toxicity and increased transduction efficiency of dcAd5-CMV/NIS in hepatoma xenografts. After PAMAM-G5 coating of the replication-selective Ad5-E1/AFP-E3/NIS, a significantly enhanced oncolytic effect was observed after intravenous application (virotherapy) that was further increased by additional treatment with a therapeutic dose of 131I (radiovirotherapy) and was associated with markedly improved survival. Conclusion: These results demonstrate efficient liver detargeting and tumor retargeting of adenoviral vectors after coating with synthetic dendrimers, thereby representing a promising innovative strategy for systemic NIS gene therapy. Moreover, our studybased on the function of NIS as a theranostic gene allowing the noninvasive imaging of NIS expression by 123I scintigraphyprovides detailed characterization of in vivo vector biodistribution and localization, level, and duration of transgene expression, essential prerequisites for exact planning and monitoring of clinical gene therapy trials that aim to individualize the NIS gene therapy concept.

【 授权许可】

Unknown