Frontal affinity chromatography with MS detection of EphB2 tyrosine kinase receptor. 2. Identification of small-molecule inhibitors via coupling with virtual screening.

We have integrated two complementary methods, high-throughput virtual screening with a "high-content" wet screening technique based on frontal affinity chromatography with mass spectrometry detection (FAC-MS), for identification of hits against the erythropoietin-producing hepatocellular B2 (EphB2) receptor tyrosine kinase domain. Both an EphB2-directed virtual screen combining docking and scoring and a kinase-directed pharmacophore search strategy were used to identify a compound set enriched in bioactive compounds against EphB2. The coupling of virtual screening methodologies with FAC-MS is a unique hybrid approach that can be used to increase the efficacy of both hit discovery and optimization efforts in drug discovery and has successfully identified hits, in particular 19a (36% shift, IC(50) = 5.2 microM, K(d) = 3.3 microM), as inhibitors for EphB2, a potential cancer target.

Global kinase screening. Applications of frontal affinity chromatography coupled to mass spectrometry in drug discovery.

Utilizing frontal affinity chromatography with mass spectrometry detection (FAC-MS), we have identified novel applications in the discovery of small-molecule hits to protein targets that are difficult if not impossible to accomplish using traditional assays. We demonstrate for the first time an ability to distinguish between competitive ligands for the ATP and substrate sites of protein kinase C independently in the same experiment and show that ATP competitive ligands using a functionally inactive receptor tyrosine kinase can be identified. This ability of FAC-MS to simultaneously monitor binding at the ATP and substrate binding sites, as well as measure ligand binding to both active and inactive kinases, suggests that FAC-MS can be used as a "global kinase binding assay".