title: Evaluation of cellular dielectric spectroscopy, a whole-cell, label-free technology for drug discovery on Gi-coupled GPCRs.
abstract: Cellular dielectric spectroscopy (CDS) is an emerging technology capable of detecting a range of whole-cell responses in a label-free manner. A new CDS-based instrument, CellKey, has been developed that is optimized for G-protein coupled receptor (GPCR) detection and has automated liquid handling in microplate format, thereby making CDS accessible to lead generation/optimization drug discovery. In addition to having sufficient throughput, new assay technologies must pass rigorous standards for assay development, signal window, dynamic range, and reproducibility to effectively support drug discovery SAR studies. Here, the authors evaluated CellKey with 3 different G(i)-coupled GPCRs for suitability in supporting SAR studies. Optimized assay conditions compatible with the precision, reproducibility, and throughput required for routine screening were quickly achieved for each target. Across a 1000-fold range in compound potencies, CellKey results correlated with agonist and antagonist data obtained using classical methods ([(35)S]GTPgammaS binding and cAMP production). For partial agonists, relative efficacy measurements also correlated with GTPgammaS data. CellKey detection of positive allosteric modulators appeared superior to GTPgammaS methodology. Agonist and antagonist activity could be accurately quantified under conditions of low receptor expression. CellKey is a new technology platform that uses label-free detection in a homogeneous assay that is unaffected by color quenching and is easily integrated into existing microtiter-based compound testing and data analysis procedures for drug discovery.
authors.affiliation: AstraZeneca Pharmaceuticals LP, Wilmington, DE 19803, USA. Matt.Peters@astrazeneca.com
authors.forename: Matthew F
authors.initials: MF
authors.lastname: Peters
authors.forename: Katharine S
authors.initials: KS
authors.lastname: Knappenberger
authors.forename: Deidre
authors.initials: D
authors.lastname: Wilkins
authors.forename: Linda A
authors.initials: LA
authors.lastname: Sygowski
authors.forename: Lois Ann
authors.initials: LA
authors.lastname: Lazor
authors.forename: Jianwei
authors.initials: J
authors.lastname: Liu
authors.forename: Clay W
authors.initials: CW
authors.lastname: Scott
mesh_terms: D000494:Allosteric Regulation; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D000242:Cyclic AMP / Q000378:metabolism; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000378:metabolism*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D006801:Humans; D043588:Receptor, Muscarinic M4 / Q000378:metabolism; D017448:Receptors, Dopamine D2 / Q000819:agonists / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015203:Reproducibility of Results; D013057:Spectrum Analysis / Q000379:methods*; D013329:Structure-Activity Relationship
chemical_list: D043588:Receptor, Muscarinic M4; D017448:Receptors, Dopamine D2; D043562:Receptors, G-Protein-Coupled; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D000242:Cyclic AMP; D019206:GTP-Binding Protein alpha Subunits, Gi-Go