Cell-based potassium ion channel screening using the FluxOR assay.
FluxOR technology is a cell-based assay used for high-throughput screening measurements of potassium channel activity. Using thallium influx as a surrogate indicator of potassium ion channel activity, the FluxOR Potassium Ion Channel Assay is based on the activation of a novel fluorescent dye. This indicator reports channel activity with a large fluorogenic response and is proportional to the number of open potassium channels on the cell, making it extremely useful for studying K(+) channel targets. In contrast to BTC-AM ester, FluxOR dye is roughly 10-fold more thallium sensitive, requiring much lower thallium for a larger signal window. This also means that the assay is carried out in a physiological, normal-chloride saline. In this article, the authors describe how they used BacMam gene delivery to express Kv7.2 and 7.3 (KCNQ), Kir2.1, or Kv11.1 (hERG) potassium ion channels in U2-OS cells. Using these cells, they ran the FluxOR assay to identify and characterize channel-specific inhibitory compounds discovered within the library (Tocriscreen Mini 1200 and Sigma Sodium/Potassium Modulators Ligand set). The FluxOR assay was able to identify several known specific inhibitors of Kv7.2/7.3 or hERG, highlighting its potential to identify novel and more efficacious small-molecule modulators.
Beacham
Daniel W
DW
Cellular Systems Division, Invitrogen Molecular Probes, Life Technologies Corporation, Eugene, Oregon 97402, USA.
Blackmer
Trillium
T
O' Grady
Michael
M
Hanson
George T
GT
D001681:Biological Assay / Q000379:methods*; D045744:Cell Line, Tumor; D054815:Cyclic Nucleotide-Gated Cation Channels / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005456:Fluorescent Dyes / Q000378:metabolism*; D006801:Humans; D020128:Inhibitory Concentration 50; D015221:Potassium Channels / Q000032:analysis*; D024661:Potassium Channels, Inwardly Rectifying / Q000378:metabolism; D054852:Small Molecule Libraries / Q000494:pharmacology; D014161:Transduction, Genetic
D054815:Cyclic Nucleotide-Gated Cation Channels; D005456:Fluorescent Dyes; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D054852:Small Molecule Libraries