Lentiviral Vectors for Gene Therapy of Cystic Fibrosis

Abstract

A replication-defective vector based on human immunodeficiency virus (HIV) was evaluated for gene transfer directed to the lung. The tropism of this vector has been expanded through the incorporation of the vesticular stomatitis virus G protein into its envelope. The HIV vector effectively transduced nondividing airway epithelial cells in vitro whereas a murine-based retroviral vector did not. Experiments in a human bronchial xenograft model demonstrated high-level gene transduction with a cystic fibrosis transmembrane conductance regulator (CFTR) HIV vector into undifferentiated, cystic fibrosis (CF)-derived cells of the xenograft. CFTR expression was stable and capable of functional correction of the CF defect after the graft matured. The HIV vector did not effectively transduce cells of the xenograft when instilled after the epithelium had differentiated. This block to transduction appears to be at the level of entry, although post entry restrictions cannot be ruled out. Further development of this vector system for CF gene therapy should focus on a better understanding of potential entry and post entry blocks.

A lentiviral vector expressing a fusogenic glycoprotein for cancer gene therapy

“…Although C-type retroviruses have been used previously, the therapeutic potential of lentiviral vectors in the context of cancer gene therapy is an area which has so far been largely untested. [27][28][29] We investigated the optimal strategies for packaging the GALV FMG cDNA into both C-type and lentiviral vectors. Expression of GALV FMG will rapidly fuse human cell lines so that stable human packaging cell lines cannot be generated.…”

Pseudotyped human lentiviral vector-mediated gene transfer to airway epithelia in vivo

“…In the only published study to date, HIV vectors pseudotyped with the vesicular stomatitis virus (VSV) glycoprotein (G) efficiently transduced undifferentiated airway epithelia, while failing to transduce the well differentiated pseudostratified columnar epithelium of mature human bronchial xenografts. 18 Given the potential advantages of HIV vectors, we explored the utility of this vector system in airway epithelia. After establishing whether HIV vectors could transduce non-dividing airway cells, we examined the ability of these vectors to transduce polarized epithelia in vitro via application of vector to the apical versus the basolateral surfaces.…”

Lentivirus-mediated gene transfer to the respiratory epithelium: a promising approach to gene therapy of cystic fibrosis

“…59 A first-generation VSV-G-pseudotyped HIV-1-derived vector was able to transduce wild-type CFTR into poorly differentiated human bronchial xenografts and its expression normalized both the chloride transport defect and reverted the bacterial killing activity. 39 Primary organotypic cultures of human trachea from patients with CF transduced with a VSV-G-pseudotyped FIVderived vector demonstrated Cl À secretion in response to cAMP agonists in a fashion similar to normal airway epithelia. 44 The correction of Cl À secretory response remained stable for 6 months.…”

“…11 Preliminary studies on the efficiency of HIV-1-derived vectors in transducing the respiratory epithelium of airway xenografts have shown that a proliferating and differentiating epithelium, but not a truly differentiated one, is susceptible to transduction. 39 Recent studies have confirmed that HIV-1-derived vectors could not transduce a fully differentiated airway epithelium unless it was injured. An HIV-1-derived vector transduced polarized tracheal epithelial cells from the apical surface only in the presence of the calcium chelator ethyleneglycol-tetraacetic acid (EGTA) and, however, at a much lower overall efficiency than was observed for polarized alveolar epithelial cells.…”