Zafirlukast inhibits the growth of lung adenocarcinoma ……

Lung cancer has the highest mortality among cancers worldwide due to its high incidence and lack of the effective cures. We have previously demonstrated that the membrane ion channel TMEM16A is a potential drug target for the treatment of lung adenocarcinoma and have identified a pocket of inhibitor binding that provides the basis for screening promising new inhibitors. However, conventional drug discovery strategies are lengthy and costly, and the unpredictable side effects lead to a high failure rate in drug development. Therefore, finding new therapeutic directions for already marketed drugs may be a feasible strategy to obtain safe and effective therapeutic drugs. Here, we screened a library of over 1400 Food and Drug Administration–approved drugs through virtual screening and activity testing. We identified a drug candidate, Zafirlukast (ZAF), clinically approved for the treatment of asthma, that could inhibit the TMEM16A channel in a concentration-dependent manner. Molecular dynamics simulations and site-directed mutagenesis experiments showed that ZAF can bind to S387/N533/R535 in the nonselective inhibitor binding pocket, thereby blocking the channel pore. Furthermore, we demonstrate ZAF can target TMEM16A channel to inhibit the proliferation and migration of lung adenocarcinoma LA795 cells. In vivo experiments showed that ZAF can significantly inhibit lung adenocarcinoma tumor growth in mice. Taken together, we identified ZAF as a novel TMEM16A channel inhibitor with excellent anticancer activity, and as such, it represents a promising candidate for future preclinical and clinical studies.

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Experimental procedures

 Drug screening

The calcium-bound structure of TMEM16A (PDB ID: 5OYB) (38) was used as a docked receptor, and the missing short loops were complemented using the SWISS-MODEL program (39, 40). Virtual screening of drugs was performed using the molecular docking program Vina (41). The database contains 1435 FDA-approved drug molecules. Autodock tool (42) was used to prepare the PDBQT files of TMEM16A and drugs. The receptor was programmed to remain rigid, while the ligand was flexible. The grid center was determined according to the center of the upper inhibitor binding pocket of the pore, with a searching space size of 24 Å3. The global search exhaustiveness value was set to 50. The maximum energy difference between the optimal binding mode and the worst case was set to 5 kcal/mol to ensure diverse docked poses. Conivaptan and Zafirlukast were purchased from DeSiTe (Chengdu, China).

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DOI：https ://doi.org/10.1016/j.jbc.2022.101731