[3H]dofetilide binding in SHSY5Y and HEK293 cells expressing a HERG-like K+ channel?

Eur J Pharmacol. 2001 Feb 2;412(3):203-12. doi: 10.1016/s0014-2999(01)00731-2.

Abstract

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.

MeSH terms

  • Animals
  • Anti-Arrhythmia Agents / metabolism*
  • Anti-Arrhythmia Agents / pharmacology
  • Benzimidazoles / pharmacology
  • Binding Sites
  • Cation Transport Proteins*
  • Cell Line
  • DNA-Binding Proteins*
  • Dose-Response Relationship, Drug
  • ERG1 Potassium Channel
  • Ether-A-Go-Go Potassium Channels
  • Humans
  • Membrane Potentials / drug effects
  • Patch-Clamp Techniques
  • Phenethylamines / metabolism*
  • Phenethylamines / pharmacology
  • Potassium Channel Blockers
  • Potassium Channels / metabolism*
  • Potassium Channels, Voltage-Gated*
  • Protein Binding
  • Quaternary Ammonium Compounds / pharmacology
  • RNA / metabolism
  • Radioligand Assay
  • Sulfanilamides / pharmacology
  • Sulfonamides / metabolism*
  • Sulfonamides / pharmacology
  • Trans-Activators*
  • Transcriptional Regulator ERG
  • Tumor Cells, Cultured

Substances

  • Anti-Arrhythmia Agents
  • Benzimidazoles
  • Cation Transport Proteins
  • DNA-Binding Proteins
  • ERG protein, human
  • ERG1 Potassium Channel
  • Ether-A-Go-Go Potassium Channels
  • KCNH2 protein, human
  • KCNH6 protein, human
  • Phenethylamines
  • Potassium Channel Blockers
  • Potassium Channels
  • Potassium Channels, Voltage-Gated
  • Quaternary Ammonium Compounds
  • Sulfanilamides
  • Sulfonamides
  • Trans-Activators
  • Transcriptional Regulator ERG
  • WAY 123398
  • RNA
  • clofilium
  • dofetilide