Cell vitality assay. To determine the cell vitality of Calu-3 cells treated with inhibitors, the CellTiter-Glo Luminescent Cell Viability Assay Kit (Promega) was used. Cells were grown in 96-well plates until reaching 50-60% confluency before they were incubated with DMSO (solvent control) or test compounds at a concentration of 10 μM for 24 h. Next, cell culture supernatants were removed, and 50 μL of the CellTiter-Glo substrate was added to each well and incubated for 30 min on a rocking platform. Finally, samples were transferred into white 96-well plates, and luminescence was measured using a Hidex Sense plate luminometer (Hidex).