[3H]dofetilide binding in SHSY5Y and HEK293 cells expressing a HERG-like K+ channel?
The pharmacological characteristics of [3H]dofetilide binding in SHSY5Y, HEK293 and CHO-K1 cells were examined, and in parallel whole cell recordings used to characterise HERG-like K+ currents. Dofetilide affinity was similar in the human cell lines, SHSY5Y (Kd=99.6 nM) and HEK293 (Kd=102.9 nM), but 10 times lower in CHO-K1 cells (Kd=1200 nM). In contrast, clofilium and E4031 had a similar affinity in all three cell lines, whereas WAY 123,398 had no effect. Electrophysiological studies showed that SHSY5Y cells contained a HERG-like K+ current blocked by application of dofetilide to either side of the membrane. Block was faster when dofetilide was applied intracellularly. In contrast, HEK293 and CHO-K1 cells contained no such current, despite the presence of a partial cDNA for HERG in the former. That [3H]dofetilide is specific for I(Kr)/HERG may be questionable, as HEK293 and CHO-K1 cells contain no such functional K+ current.
Finlayson
K
K
Fujisawa Institute of Neuroscience, Department of Neuroscience, University of Edinburgh, 1 George Square, EH8 9JZ, Edinburgh, UK. Keith.Finlayson@ed.ac.uk
Pennington
A J
AJ
Kelly
J S
JS
D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000378:metabolism* / Q000494:pharmacology; D001562:Benzimidazoles / Q000494:pharmacology; D001665:Binding Sites; D027682:Cation Transport Proteins; D002460:Cell Line; D004268:DNA-Binding Proteins; D004305:Dose-Response Relationship, Drug; D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; D006801:Humans; D008564:Membrane Potentials / Q000187:drug effects; D018408:Patch-Clamp Techniques; D010627:Phenethylamines / Q000378:metabolism* / Q000494:pharmacology; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000378:metabolism*; D024642:Potassium Channels, Voltage-Gated; D011485:Protein Binding; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology; D012313:RNA / Q000378:metabolism; D011869:Radioligand Assay; D013424:Sulfanilamides / Q000494:pharmacology; D013449:Sulfonamides / Q000378:metabolism* / Q000494:pharmacology; D015534:Trans-Activators; D000071230:Transcriptional Regulator ERG; D014407:Tumor Cells, Cultured; D000096926:Benzenesulfonamides
D000889:Anti-Arrhythmia Agents; D001562:Benzimidazoles; D027682:Cation Transport Proteins; D004268:DNA-Binding Proteins; D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; D010627:Phenethylamines; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D000644:Quaternary Ammonium Compounds; D012313:RNA; D013424:Sulfanilamides; D013449:Sulfonamides; D015534:Trans-Activators; D000071230:Transcriptional Regulator ERG; C072312:ERG protein, human; C000606913:KCNH2 protein, human; C092509:KCNH6 protein, human; C073190:WAY 123398; D000096926:Benzenesulfonamides; C022799:clofilium; C063533:dofetilide