Restoration of cyclic adenosine monophosphate-stimulated chloride channel activity in human cystic fibrosis tracheobronchial submucosal gland cells by adenovirus-mediated and cationic lipid-mediated gene transfer

In human airways, the cystic fibrosis (CF) transmembrane conductance regula tor (CFTR) is predominantly expressed in serous cells of the tracheobronchi al glands. Despite considerable evidence that submucosal glands are importa nt contributors to the pathophysiology of CF lung disease, most attempts at CFTR gene transfer have primarily targeted airway surface epithelial cells . In this study, we systematically evaluated CFTR gene transfer into cultur es of immortalized CF human tracheobronchial submucosal gland (6CFSMEO) cel ls using adenovirus and cationic Lipid vectors. We found that the efficienc y of adenovirus-mediated gene transfer was comparable in 6CFSMEO and CFT1 c ells (a surface airway epithelial cell line isolated from a subject with CF ). So was the ranking order of adenovirus vectors containing different enha ncers/promoters (CMV >> Ela similar to phosphoglycerokinase), as determined by both X-Gal staining and quantitative measurement of P-galactosidase act ivity. Further, we provide the first demonstration that cationic lipids med iate efficient gene transfer into 6CFSMEO cells in vitro. The transfection efficiency at optimal conditions was higher in 6CFSMEO than in CFT1 cells. Finally, either infection with adenoviral vectors or transfection with cati onic lipid:plasmid DNA complexes encoding CFTR significantly increased chlo ride (Cl-) permeability, as assessed using the 6-methoxy-N-(3-sulfopropyl)- quinolinium (SPQ) fluorescence assay, indicating restoration of functional CFTR Cl- channel activity. These data show that although the mechanisms of transfection may be different between the two cell types, 6CFSMEO cells are as susceptible as CFT1 cells to transfection by adenoviral and cationic-li pid gene transfer vectors.