ω-Conotoxin GVIA Mimetics that Bind and Inhibit Neuronal Cav2.2 Ion Channels

Abstract

The neuronal voltage-gated N-type calcium channel (Cav2.2) is a validated target for the treatment of neuropathic pain. A small library of anthranilamide-derived ω-Conotoxin GVIA mimetics bearing the diphenylmethylpiperazine moiety were prepared and tested using three experimental measures of calcium channel blockade. These consisted of a 125I-ω-conotoxin GVIA displacement assay, a fluorescence-based calcium response assay with SH-SY5Y neuroblastoma cells, and a whole-cell patch clamp electrophysiology assay with HEK293 cells stably expressing human Cav2.2 channels. A subset of compounds were active in all three assays. This is the first time that compounds designed to be mimics of ω-conotoxin GVIA and found to be active in the 125I-ω-conotoxin GVIA displacement assay have also been shown to block functional ion channels in a dose-dependent manner.

Synthesis of 2-anilinobenzimidates, anthranilamides, and 2,3-dihydroquinazolin-4(1H)-ones from N-heterocyclic carbenes of indazole

“…6 Concerning the biological activities, derivatives of II have been described recently as substrates for the antibacterial target undecaprenyl pyrophosphate synthase, 7 as modulators of the expression of micro RNAs in neuroblastoma cells which cause cell cycle arrest and apoptosis, 8 as inhibitors for Pseudomonas aeruginosa infections 9 and of SIRT, 10 and of neuronal ion channels. 11 Syntheses and structureactivity relationships of orally active anthranilamide-based factor Xa inhibitors have been studied as well. 12 Apart from their biological significance, anthranilamides II are versatile starting materials for further chemical transformations.…”

Recent Progress in the Discovery and Development of N-Type Calcium Channel Modulators for the Treatment of Pain

“…Truncation at the Lys2 moiety in (2) produced a mimetic for Tyr13 and Arg17 having similar potency but substantially reduced molecular weight (5) [105]. Hybrid approaches combining the anthranilamide and a diphenylmethylpiperazine commonly found in small molecule blockers of N-type channels also displayed low micromolar potency (6) [106]. A virtual screening approach to identify cyclic pentapetides mimicking crucial residues of CVID has also been reported to demonstrate selectivity for N-type channels (7) [107].…”

Conotoxins and Other Conopeptides

“…A fluorescentbased assay known as FLIPR 1 has also been used to measure the activity of conopeptides on ion channels (Tranberg et al, 2012;Vetter et al, 2012). Based on the dose-response curves, the halfmaximum inhibitory concentration (IC 50 ) can be computed, and in turn the inhibitory constant K i can be inferred.…”