Background: Aerosol-based inhalation therapy is widely used for the treatment of lung diseases, but reliable drug screening approaches in complex phenotypic settings (e.g. cell systems) at the air-liquid interface (ALI) are unavailable. Here, we introduce the ALICE-CLOUD technology, which utilizes the principles of cloud motion for delivery of bioactive aerosolized liquid drugs to pulmonary cell types cultured under physiologically realistic ALI conditions.
Methods: Drug-to-cell delivery efficiency of the ALICE-CLOUD was investigated with fluoresceine as surrogate drug. A novel candidate drug for anti-inflammatory inhalation therapy Bortezomib (Velcade®) was investigated by stimulating human alveolar epithelial cells (A549) with TNFα resulting in a 7-8-fold activation of the IL-8 promoter. Bortezomib (Velcade®) was applied to the cells and the effect on IL-8 promotor activation and proteasome activity was investigated in cell lysates using a luciferase reporter assays. Cytotoxicity was monitored with the WST-1 and LDH assays.
Results: For 200 μL of nebulized liquid, 33.6 μL was delivered within 3.5 min to 6-well transwell inserts (5.6 μL per insert) corresponding to a 16.8% delivery efficiency. The reproducibility of the dose was 9.3% and the insert-insert variability was 4.3%. We found that Bortezomib (Velcade®) can be aerosolized to efficiently block proteasomal activity and mediate potent anti-inflammatory effects in A549 cells cultured at ALI conditions. Importantly, aerosolized and liquid (non-aerosolized) drug delivery showed identical drug efficacy. Of note, the response kinetics of aerosolized Bortezomib was by about a factor of 12 faster than non-aerosolized Bortezomib delivered under submerged conditions.
Conclusion: Our data validate the ALICE-CLOUD as an easy-to-handle, quantitative, and highly suitable tool for preclinical screening for inhalation drugs at realistic conditions. Moreover, we identify Bortezomib – and possibly also other representatives of this class of biopharmaceutics – as a promising candidate for inhalation therapy.