Synthesis and Structure-activity Relationship of Aminoarylthiazole Derivatives as Potential Potentiators of the Chloride Transport Defect in Cystic Fibrosis

Background: Cystic fibrosis (CF) is the autosomal recessive disorder most common in Caucasian populations. It is caused by mutations in the cystic fibrosis transmembrane regulator protein (CFTR). CFTR is predominantly expressed at the apical plasma membranes of the epithelial cells lining several organs, and functions as a cAMP-regulated chloride/bicarbonate channel. To address the underlying causes of cystic fibrosis, two biomolecular activities are required, namely correctors to increase CFTR levels at the cell surface, and potentiators to allow the effective opening of the CFTR channel. Objective: In our previous data, we demonstrated that some aminoarylthiazoles (AATs) have peculiar activity acting as correctors and as potentiator-like molecules. Curiously, a compound called 1 has been shown to be markedly active as a potentiator. Now, we have further modified its scaffold at different portions, for the identification of molecules with improved potency and effectiveness on mutant CFTR. Methods: Starting from this active compound, we synthesized a small library trying to improve the activity as potentiators. To extrapolate the contribution of a particular structural portion to bioactivity, we selectively modified one portion at a time. Results: Our study has provided a structure-activity relationship (SAR) on AATs and led to the identification of some compounds, with a particular ability to act as CFTR potentiators. Conclusion: Two compounds 2 and 13 appear to be promising molecules and could be used for the future development of potentiators of the chloride transport defect in cystic fibrosis.