Lacosamide Isothiocyanate-Based Agents: Novel Agents To Target and Identify Lacosamide Receptors

Abstract

Abstract(R)-Lacosamide ((R)-2, (R)-N-benzyl 2-acetamido-3-methoxypropionamide), has recently gained regulatory approval for the treatment of partial-onset seizures in adults. Whole animal pharmacological studies have documented that (R)-2 function is unique. A robust strategy is advanced for the discovery of interacting proteins associated with function and toxicity of (R)-2 through the use of (R)-2 analogs, 3, that contain "affinity bait (AB)" and "chemical reporter (CR)" functional groups. In 3, covalent modification of the interacting proteins proceeds at the AB moiety, and detection or isolation of the selectively captured protein occurs through the bioorthogonal CR group upon reaction with an appropriate probe. We report the synthesis, pharmacological evaluation, and interrogation of the mouse soluble brain proteome using 3 where the AB group is an isothiocyanate moiety. One compound, (R)-N-(4-isothiocyanato)benzyl 2-acetamido-3-(prop-2-ynyloxy) propionamide ((R)-9), exhibited excellent seizure protection in mice and, like (R)-2, anticonvulsant activity principally resided in the (R)-stereoisomer. Several proteins were preferentially labeled by (R)-9 compared with (S)-9, including collapsin response mediator protein 2.

In Silico Docking and Electrophysiological Characterization of Lacosamide Binding Sites on Collapsin Response Mediator Protein-2 Identifies a Pocket Important in Modulating Sodium Channel Slow Inactivation

“…Using a chemical proteomics approach, we recently reported CRMP-2 interactions with AB&CR-LCM in mouse brain lysates as well as with recombinant CRMP-2 (9). CRMP-2 labeling was confirmed with differential stable isotope labeling followed by liquid chromatography-tandem mass spectrometry, revealing a selective ϳ80% increase in relative levels of CRMP-2 by (R)-, but not (S)-, LCM (9). In this study, we have extended these earlier findings by demonstrating labeling of CRMP-2 in rat brain soluble lysates.…”

“…In this study we investigated how CRMP-2, a recently identified target of LCM's action (9), affects LCM's modulation of its primary clinical target, the voltage-gated Na ϩ channels. Fast inactivation was unaffected by LCM treatment.…”

“…This ability to preferentially block the electrical activity of neurons that are chronically depolarized compared with those at more normal resting potentials sets LCM apart from classic VGSCtargeted anti-epileptic drugs such as carbamazepine, phenytoin, and lamotrigine (7). In addition, protein pulldown assays and a combined chemical-proteomics approach have provided evidence that lacosamide interacts with collapsin response mediator protein 2 (CRMP-2), an axonal growth and guidance protein (8,9). The role of CRMP-2 in the action(s) of lacosamide is not known.…”

“…Using a chemically modified lacosamide harboring "affinity bait" (AB) and "chemical reporter" (CR) moieties, we recently demonstrated lacosamide AB&CR labeling of expressed as well as endogenous CRMP-2 in mouse brain lysate (9). Here, we tested if lacosamide AB&CR adduction could be competed off using excess (R)-lacosamide.…”

Synthesis of a series of unsaturated ketone derivatives as selective and reversible monoamine oxidase inhibitors

“…22 For 2'-substituted Cl compounds 12b, 13b, 14b and 15b, 2-chloro cinnamoyl chloride were directly coupled with the desired aniline with triethylamine in DMF (Scheme 2). …”