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.
Footnotes
- Received May 23, 2013.
- Accepted August 30, 2013.
C.J.L. and E.J.R. contributed equally to this work.
This work was supported by the Korea Institute of Science and Technology Institutional Program [Grant 2E24182]; the World Class Institute Program of the National Research Foundation of Korea funded by the Ministry of Education, Science and Technology of Korea [Grant WCI 2009-003]; the National Institutes of Health National Institute of General Medical Sciences [Grant R01 GM60448]; the National Institutes of Health National Eye Institute [Grant R01 EY11482]; and a pilot grant from the Emory Center for Cystic Fibrosis Research of Children’s Healthcare of Atlanta.
↵This article has supplemental material available at molpharm.aspetjournals.org.
S.-J.O. and S.J.H. contributed equally to this work.
- Copyright © 2013 by The American Society for Pharmacology and Experimental Therapeutics