Human bronchial epithelial BEAS-2B cells were cultured in RPMI growth medium, supplemented with 10% FCS, 1% penicillin/streptomycin at 37°C in a humidified incubator at 5% CO2. Human primary bronchial epithelial cell cultures (primary HBE) were bought from Lonza (Visp, Switzerland) or isolated from biopsies from individuals treated by lobectomy because of non-small-cell lung carcinoma at the Thoraxklinik Heidelberg. Ethics approval (S-381/2014) was obtained from the regional Ethics Committee at the University of Heidelberg, and all study participants provided a written informed consent. Two methods of bronchial epithelial cells isolation were used (65, 66): Briefly, the obtained biopsies were washed with cold EBSS and cleaned from any additional connective tissue and mucus. The segments were then cut open and incubated on a shaker at 4°C overnight in 9 ml EBSS including 1 ml digestion solution (DS, 10x: 0.01% DNase I, 1% Protease XIV in sterile PBS). On the next day, 1.1 ml FCS was added to the solution to terminate digestion. The epithelium was scraped into the digestion medium using a sterile scalpel. The biopsies were additionally washed with EBSS. All epithelial cells from scraping were collected by spinning at 4°C at 500 × g for 5 min. Cell pellets were resuspended in 10 ml of warm BEGM (Lonza) and cells were then seeded into collagen-coated (3 mg/ml PureCol, Cellsystems, 1:75 in ddH2O) prewarmed 10 cm culture dishes.