Cellular HTS assays for pharmacological characterization of Na(V)1.7 modulators.
Ion channels are challenging targets in the early phases of the drug discovery process, especially because of the lack of technologies available to screen large numbers of compounds in functionally relevant assays. The electrophysiological patch-clamp technique, which is the gold standard for studying ion channels, has low throughput and is not amenable to screening large numbers of compounds. However, for random high-throughput screening (HTS) of compounds against ion channel targets, a number of functional cellular assays have become available during the last few years. Here we use the sodium channel NaV1.7 stably expressed in human embryonic kidney 293 cells and compare three HTS assays-a Li flux atomic absorption spectroscopy (AAS) assay, a fluorescent imaging plate reader (FLIP, Molecular Devices, Sunnyvale, CA) membrane potential assay, and a fluorescence resonance energy transfer (FRET)-based membrane potential assay-to an automated electrophysiological assay (the Ionworks HT [Molecular Devices] platform) and characterize 11 known NaV inhibitors. Our results show that all three HTS assays are suitable for identification of NaV1.7 inhibitors, but as an HTS assay the Li-AAS assay is more robust with higher Z' values than the FLIPR and FRET-based membrane potential assays. Furthermore, there was a better correlation between the Ionworks assay and the Li-AAS assay regarding the potency of the NaV inhibitors investigated. This paper describes the first comparison between all the HTS assays available today to study voltage-gated NaVs, and the results suggest that the Li-AAS assay is more suited as a first HTS assay when starting an NaV drug discovery campaign.
Trivedi
Shephali
S
HTS Center and Global Support Department, AstraZeneca Pharmaceuticals, Wilmington, DE 19850, USA. shephali.trivedi@astrazeneca.com
Dekermendjian
Kim
K
Julien
Ronald
R
Huang
Jian
J
Lund
Per-Eric
PE
Krupp
Johannes
J
Kronqvist
Robert
R
Larsson
Olof
O
Bostwick
Robert
R
D002460:Cell Line; D002478:Cells, Cultured; D003627:Data Interpretation, Statistical; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D004594:Electrophysiology; D031541:Fluorescence Resonance Energy Transfer; D005456:Fluorescent Dyes; D006801:Humans; D008094:Lithium / Q000737:chemistry / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D062556:NAV1.7 Voltage-Gated Sodium Channel; D026941:Sodium Channel Blockers / Q000494:pharmacology*; D015222:Sodium Channels / Q000187:drug effects*; D013054:Spectrophotometry, Atomic
D005456:Fluorescent Dyes; D062556:NAV1.7 Voltage-Gated Sodium Channel; C486866:SCN9A protein, human; D026941:Sodium Channel Blockers; D015222:Sodium Channels; D008094:Lithium