Viral vectors for cystic fibrosis gene therapy: What does the future hold?

Abstract

Correspondence: Uta Griesenbach Department of Gene Therapy, Faculty of Medicine at the National Heart and Lung institute, imperial College London, Manresa Road, London Sw3 6LR, UK Tel +44 207 351 8339 Fax +44 207 351 8340 email u.griesenbach@imperial.ac.uk Abstract: Gene transfer to the airway epithelium has been more difficult than originally anticipated, largely because of significant extraand intracellular barriers in the lung. In general, viral vectors are more adapted to overcoming these barriers than nonviral gene transfer agents and are, therefore, more efficient in transferring genes into recipient cells. Viral vectors derived from adenovirus, adeno-associated virus, and Sendai virus, which all have a natural tropism for the airway epithelium, have been evaluated for cystic fibrosis (CF) gene therapy. Although these vectors transduce airway epithelial cells efficiently, gene expression is transient and repeated administration is inefficient. They are, therefore, unlikely to be suitable for CF gene therapy. More recently, lentiviruses (LV) have been assessed for lung gene transfer. In contrast to retroviruses, they transduce nondividing cells and randomly integrate into the genome. However, LVs do not have a natural tropism for the lung, and a significant amount of effort has been put into pseudotyping these vectors with proteins suitable for airway gene transfer. Several studies have shown that LV-mediated transduction leads to persistent gene expression (for the lifetime of the animal) in the airways and, importantly, repeated administration is feasible. Thus, appropriately pseudotyped LV vectors are promising candidates for CF gene therapy. Here, we will review preclinical and clinical research related to viral CF gene therapy.