title: Potentiators of Defective ΔF508-CFTR Gating that Do Not Interfere with Corrector Action.
abstract: Combination drug therapies under development for cystic fibrosis caused by the ∆F508 mutation in cystic fibrosis transmembrane conductance regulator (CFTR) include a "corrector" to improve its cellular processing and a "potentiator" to improve its chloride channel function. Recently, it was reported that the approved potentiator N-(2,4-di-tert-butyl-5-hydroxyphenyl)-4-oxo-1,4-dihydroquinoline-3-carboxamide (Ivacaftor) reduces ∆F508-CFTR cellular stability and the efficacy of investigational correctors, including 3-(6-[([1-(2,2-difluoro-1,3-benzodioxol-5-yl)cyclopropyl]carbonyl) amino]-3-methyl-2-pyridinyl)-benzoic acid and 1-(2,2-difluoro-1,3-benzodioxol-5-yl)-N-(1-[(2R)-2,3-dihydroxypropyl]-6-fluoro-2-(2-hydroxy-1,1-dimethylethyl)-1H-indol-5-yl), which might contribute to the modest reported efficacy of combination therapy in clinical trials. Here, we report the identification and characterization of potentiators that do not interfere with ∆F508-CFTR stability or corrector action. High-throughput screening and structure-activity analysis identified several classes of potentiators that do not impair corrector action, including tetrahydrobenzothiophenes, thiooxoaminothiazoles, and pyrazole-pyrrole-isoxazoles. The most potent compounds have an EC(50) for ∆F508-CFTR potentiation down to 18 nM and do not reduce corrector efficacy in heterologous ∆F508-CFTR-expressing cells or primary cultures of ∆F508/∆F508 human bronchial epithelia. The ΔF508-CFTR potentiators also activated wild-type and G551D CFTR, albeit weakly. The efficacy of combination therapy for cystic fibrosis caused by the ∆F508 mutation may be improved by replacement of Ivacaftor with a potentiator that does not interfere with corrector action.
authors.affiliation: Departments of Medicine and Physiology (P.-W.P., J.A.T., A.S.V.) and Department of Pathology (W.E.F.), University of California, San Francisco, California; Department of Physiology and Groupe de Recherche Axé sur la Structure des Protéine (G.V., G.L.L.) and Department of Biochemistry (G.L.L.), McGill University, Montreal, Quebec, Canada.
authors.forename: Puay-Wah
authors.initials: PW
authors.lastname: Phuan
authors.affiliation: Departments of Medicine and Physiology (P.-W.P., J.A.T., A.S.V.) and Department of Pathology (W.E.F.), University of California, San Francisco, California; Department of Physiology and Groupe de Recherche Axé sur la Structure des Protéine (G.V., G.L.L.) and Department of Biochemistry (G.L.L.), McGill University, Montreal, Quebec, Canada.
authors.forename: Guido
authors.initials: G
authors.lastname: Veit
authors.affiliation: Departments of Medicine and Physiology (P.-W.P., J.A.T., A.S.V.) and Department of Pathology (W.E.F.), University of California, San Francisco, California; Department of Physiology and Groupe de Recherche Axé sur la Structure des Protéine (G.V., G.L.L.) and Department of Biochemistry (G.L.L.), McGill University, Montreal, Quebec, Canada.
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Tan
authors.affiliation: Departments of Medicine and Physiology (P.-W.P., J.A.T., A.S.V.) and Department of Pathology (W.E.F.), University of California, San Francisco, California; Department of Physiology and Groupe de Recherche Axé sur la Structure des Protéine (G.V., G.L.L.) and Department of Biochemistry (G.L.L.), McGill University, Montreal, Quebec, Canada.
authors.forename: Walter E
authors.initials: WE
authors.lastname: Finkbeiner
authors.affiliation: Departments of Medicine and Physiology (P.-W.P., J.A.T., A.S.V.) and Department of Pathology (W.E.F.), University of California, San Francisco, California; Department of Physiology and Groupe de Recherche Axé sur la Structure des Protéine (G.V., G.L.L.) and Department of Biochemistry (G.L.L.), McGill University, Montreal, Quebec, Canada.
authors.forename: Gergely L
authors.initials: GL
authors.lastname: Lukacs
authors.affiliation: Departments of Medicine and Physiology (P.-W.P., J.A.T., A.S.V.) and Department of Pathology (W.E.F.), University of California, San Francisco, California; Department of Physiology and Groupe de Recherche Axé sur la Structure des Protéine (G.V., G.L.L.) and Department of Biochemistry (G.L.L.), McGill University, Montreal, Quebec, Canada Alan.Verkman@ucsf.edu.
authors.forename: A S
authors.initials: AS
authors.lastname: Verkman
mesh_terms: D000631:Aminopyridines / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D052117:Benzodioxoles / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D003550:Cystic Fibrosis / Q000378:metabolism / Q000473:pathology; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000819:agonists / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D011916:Rats, Inbred F344; D013329:Structure-Activity Relationship
chemical_list: D000631:Aminopyridines; D052117:Benzodioxoles; C093349:cystic fibrosis transmembrane conductance regulator delta F508; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; C569105:lumacaftor