Abstract | BACKGROUND/AIMS: METHODS: We tested the affinity of lubeluzole, its enantiomer, and the racemate for hERG channel using the patch-clamp technique. We synthesized and tested two simplified model compounds corresponding to two moieties included in the lubeluzole structure. The obtained experimental results were rationalized by docking simulation on the recently reported cryo-electron microscopy (cryo-EM) structure of hERG. Group efficiency analysis was performed in order to individuate the fragment most contributing to binding. RESULTS: We found that lubeluzole and its R enantiomer are highly potent inhibitors of human ether-ago-go-related gene (hERG) channel with an IC50 value of 12.9 ± 0.7 nM and 11.3 ± 0.8 nM, respectively. In the presence of lubeluzole, steady-state activation and inactivation of hERG channel were shifted to more negative potentials and inactivation kinetics was accelerated. Mutations of aromatic residues (Y652A and F656A) in the channel inner cavity significantly reduced the inhibitory effect of lubeluzole. Molecular docking simulations performed on the near atomic resolution cryo-electron microscopy structures of hERG supported the role of Y652 and F656 as the main contributors to high affinity binding. Group efficiency analysis indicated that both 1,3-benzothiazol-2-amine and 3-aryloxy-2-propanolamine moieties contribute to drug binding with the former giving higher contribution. CONCLUSIONS: This study suggests the possibility to modulate lubeluzole hERG blockade by introducing suitable substituents onto one or both constituting portions of the parent compound in order to either reduce potency (i. e. torsadogenic potential) or potentiate affinity (useful for class III antiarrhythmic and anticancer agent development).
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Authors | Roberta Gualdani, Maria Maddalena Cavalluzzi, Francesco Tadini-Buoninsegni, Marino Convertino, Philippe Gailly, Anna Stary-Weinzinger, Giovanni Lentini |
Journal | Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology
(Cell Physiol Biochem)
Vol. 45
Issue 6
Pg. 2233-2245
( 2018)
ISSN: 1421-9778 [Electronic] Germany |
PMID | 29550817
(Publication Type: Journal Article)
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Copyright | © 2018 The Author(s). Published by S. Karger AG, Basel. |
Chemical References |
- Ether-A-Go-Go Potassium Channels
- Neuroprotective Agents
- Piperidines
- Thiazoles
- lubeluzole
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Topics |
- Animals
- CHO Cells
- Cricetulus
- Ether-A-Go-Go Potassium Channels
(antagonists & inhibitors, chemistry, genetics, metabolism)
- HEK293 Cells
- Humans
- Molecular Docking Simulation
- Neuroprotective Agents
(pharmacology)
- Patch-Clamp Techniques
- Piperidines
(pharmacology)
- Point Mutation
- Protein Binding
- Protein Conformation, alpha-Helical
- Thiazoles
(pharmacology)
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