title: MONNA, a potent and selective blocker for transmembrane protein with unknown function 16/anoctamin-1.
abstract: Transmembrane protein with unknown function 16/anoctamin-1 (ANO1) is a protein widely expressed in mammalian tissues, and it has the properties of the classic calcium-activated chloride channel (CaCC). This protein has been implicated in numerous major physiological functions. However, the lack of effective and selective blockers has hindered a detailed study of the physiological functions of this channel. In this study, we have developed a potent and selective blocker for endogenous ANO1 in Xenopus laevis oocytes (xANO1) using a drug screening method we previously established (Oh et al., 2008). We have synthesized a number of anthranilic acid derivatives and have determined the correlation between biological activity and the nature and position of substituents in these derived compounds. A structure-activity relationship revealed novel chemical classes of xANO1 blockers. The derivatives contain a --NO₂ group on position 5 of a naphthyl group-substituted anthranilic acid, and they fully blocked xANO1 chloride currents with an IC₅₀ < 10 μM. The most potent blocker, N-((4-methoxy)-2-naphthyl)-5-nitroanthranilic acid (MONNA), had an IC₅₀ of 0.08 μM for xANO1. Selectivity tests revealed that other chloride channels such as bestrophin-1, chloride channel protein 2, and cystic fibrosis transmembrane conductance regulator were not appreciably blocked by 10∼30 μM MONNA. The potent and selective blockers for ANO1 identified here should permit pharmacological dissection of ANO1/CaCC function and serve as potential candidates for drug therapy of related diseases such as hypertension, cystic fibrosis, bronchitis, asthma, and hyperalgesia.
authors.affiliation: Center for Neuroscience and Center for Functional Connectomics, Brain Science Institute (S.-J.O., J.J., J.K., J.Y.C., C.J.L.), and Chemical Kinomics Research Center, Future Convergence Research Division (S.J.H., E.J.R.), Korea Institute of Science and Technology (KIST), Seoul, Korea; Neuroscience Program, University of Science and Technology, Daejeon, Korea (C.J.L.); KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, Korea (C.J.L.); and Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia (K.Y., H.C.H.).
authors.forename: Soo-Jin
authors.initials: SJ
authors.lastname: Oh
authors.forename: Seok Jin
authors.initials: SJ
authors.lastname: Hwang
authors.forename: Jonghoon
authors.initials: J
authors.lastname: Jung
authors.forename: Kuai
authors.initials: K
authors.lastname: Yu
authors.forename: Jeongyeon
authors.initials: J
authors.lastname: Kim
authors.forename: Jung Yoon
authors.initials: JY
authors.lastname: Choi
authors.forename: H Criss
authors.initials: HC
authors.lastname: Hartzell
authors.forename: Eun Joo
authors.initials: EJ
authors.lastname: Roh
authors.forename: C Justin
authors.initials: CJ
authors.lastname: Lee
mesh_terms: D000818:Animals; D000075369:Anoctamin-1; D018118:Chloride Channels / Q000037:antagonists & inhibitors*; D004353:Drug Evaluation, Preclinical; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors*; D013329:Structure-Activity Relationship; D014982:Xenopus laevis; D062367:ortho-Aminobenzoates / Q000494:pharmacology*
chemical_list: C476213:ANO1 protein, human; D000075369:Anoctamin-1; D018118:Chloride Channels; C585066:N-((4-methoxy)-2-naphthyl)-5-nitroanthranilic acid; D009363:Neoplasm Proteins; D062367:ortho-Aminobenzoates