Rescuing defective CFTR applying a drug repositioning strategy based on computational studies, surface plasmon resonance and cell-based assays

Cystic Fibrosis (CF) is caused by mutations (mainly F508del) of the cystic fibrosis transmembrane conductance regulator (CFTR). Current CF therapies are aimed at symptoms alleviation, calling for new drugs to rescue CFTR function. Hypothesis and objectives Drug repositioning is aimed at finding new applications for already marketed drugs, reducing cost and duration and the likelihood of unforeseen adverse events. In this project we have integrated drug repositioning with computational studies, surface plasmon resonance (SPR) [1] and well-tried cellular models [2] to identify new CF drugs and to comprehend their mechanism of action. Methods and results We have prepared a new structural homology model of intact human F508del-CFTR embedded in a phospholipid bilayer and a SPR biosensor containing the same protein in a cell membrane-mimicking lipid film. These tools, along with appropriate cell-based assays, have been firstly used to analyze a mixed library of well-known and new compounds that allowed the validation of the system and the identification of a promising molecule endowed with a F508del-binding and rescuing capacity that is higher than those of drugs already in use. With the computational model we have then performed a virtual drug repositioning on a library of 846 drugs, identifying 10 drugs that were reduced to 4 on the basis of toxicity profile and patient compliance. These drugs will be now subjected to experimental analysis by cell-based and SPR assays for their effective capacity to bind F508del-CFTR and rescue its activity. Also, we will proceed to the virtual repositioning of a library of natural compounds. Spin-off for research & clinical purposes The novel computational models and biosensors will widen the study of CF drugs and made available to other research groups in the field of CF. References 1. Rusnati M, Sala D, Orro A, Bugatti A, Trombetti G, Cichero E, Urbinati C, Di Somma M, Millo E, Galietta LJV, Milanesi L, Fossa P, D'Ursi P. Speeding Up the Identification of Cystic Fibrosis Transmembrane Conductance Regulator-Targeted Drugs: An Approach Based on Bioinformatics Strategies and Surface Plasmon Resonance. Molecules. 2018 Jan 8;23(1). pii: E120. doi: 10.3390/molecules23010120. 2. Tomati V, Pesce E, Caci E, Sondo E, Scudieri P, Marini M, Amato F, Castaldo G, Ravazzolo R, Galietta LJV, Pedemonte N. High-throughput screening identifies FAU protein as a regulator of mutant cystic fibrosis transmembrane conductance regulator channel. J Biol Chem. 2018 Jan 26;293(4):1203-1217. doi: 10.1074/jbc.M117.816595. Epub 2017 Nov 20. Acknowledgment FFC#11/2018 funded by FFC and supported by Delegazione FFC di Torino