In vitro study | The act of VX-809 acting at the level of the estrogen receptor (ER) causes a part of the F508del-CFTR to take a correctly folded way, exit the ER, transfer to the cell surface, and function normally. VX-809 acting on F508del-CFTR-expressing Fischer Rat Thyroid (FRT) cells VX-809 significantly increase F508del-CFTR mutation by 7.1 times with an EC50 of 0.1 μm and enhance F508del-CFTR-regulated chloride transport, the EC50 is 0.5 μm when it is increased by 5 times, while the EC50 is 7.9 μm and 16 μm when it is VRT-768. VX-809 (3 μm) acts on F508del-CFTR-expressing HEK-293 cells and increases F508del-CFTR in ER by a factor of 6. VX-809 increased CFTR maturation and chloride secretion in primary human bronchial epithelial (HBE) cells carrying F508del-CFTR mutations, with EC50 values of 350 nM and 81 nM, respectively, more effective than Corr-4a and VRT-325. VX-809 modified F508del-CFTR has a single channel development probability of 0.39, which is similar to the normal CFTR, which is 0.40. Unlike VX-770, VX-809 are not CFTR enhancers, and sharp addition of VX-809 does not affect F508del-CFTR function. In contrast to VRT-325 and Corr-4a, VX-809 does not promote the progression of normal or mutant forms of hERG or P-gp, and other disease-causing mislocalized proteins, including the α1-antitrypsin Z mutation (E342K-α1-AT) or N370S-β-glucosidase, indicating that VX-809 acts specifically on CFTR. |