An ex vivo human model system to evaluate specificity of replicating and non-replicating gene therapy agents.
Rots, M. G. 1,*; Elferink, M. G. L. 2; Gommans, W. M. 1; Oosterhuis, D. 1; Schalk, J. A. C. 3; Curiel, D. T. 4; Olinga, P. 2; Haisma, H. J. 1; Groothuis, G. M. M. 2
[Article]
The Journal of Gene Medicine.
8(1):35-41, January 2006.
(Format: HTML, PDF)
Background: Inefficiency, aspecificity and toxicity of gene transfer vectors hamper gene therapy from showing its full potential. On this basis significant research currently focuses on developing vectors with improved infection and/or expression profiles. Screening assays with validity to the clinical context to determine improved characteristics of such agents are not readily available since this requires a close relationship to the human situation. We present a clinically relevant tissue slice technology to preclinically test improved vector characteristics.
Methods: Slices were prepared from rat, mouse and human liver samples and from tumor tissue. Specificity of gene expression and replication was determined by infecting target and non-target tissue slices with transcriptionally retargeted adenoviruses and oncolytic viruses.
Results: Using rat liver slices, we demonstrate efficient knob-mediated adenoviral infectivity. A favorable tumor-on/liver-off profile, resembling in vitro and mouse in vivo data, was shown for a tumor-specific transcriptionally retargeted adenovirus by infecting slices prepared from tumor or liver tissue. Similar liver-off data were found for mouse, rat and human samples (over 3-log lower activity of the tumor-specific promoter compared to cytomegalovirus (CMV)). More importantly, we show that this technology when applied to human livers is a powerful tool to determine aspecific replication of oncolytic viruses in liver tissue. A 2- to 6-log reduction in viral replication was observed for a tumor-specific oncolytic virus compared to the wild-type adenovirus.
Conclusions: The precision-cut tissue slice technology is a powerful method to test specificity and efficiency of gene transfer as well as of viral replication using human tissue. Copyright (C) 2005 John Wiley & Sons, Ltd.
Copyright (C) 2006 John Wiley & Sons, Inc.