Assessment of Bromodomain Target Engagement by a Series of BI2536 Analogues with Miniaturized BET-BRET

• Published in: ChemMedChem Vol. 11; no. 23; pp. 2575 - 2581
• Main Authors: Koblan, Luke W., Buckley, Dennis L., Ott, Christopher J., Fitzgerald, Mark E., Ember, Stuart W. J., Zhu, Jin-Yi, Liu, Shuai, Roberts, Justin M., Remillard, David, Vittori, Sarah, Zhang, Wei, Schonbrunn, Ernst, Bradner, James E.
• Format: Journal Article
• Language: English
• Published: WEINHEIM Blackwell Publishing Ltd 06.12.2016; Wiley; Wiley Subscription Services, Inc
• Subjects: bromodomain inhibition; Cell Cycle Checkpoints - drug effects; Cell Cycle Proteins - antagonists & inhibitors; Cell Cycle Proteins - metabolism; Cell Survival - drug effects; Chemistry, Medicinal; Drug Design; Energy transfer; Enzyme inhibitors; epigenetics; Evaluation; fluorescence; Fluorescence Resonance Energy Transfer; Fluorescent Dyes - chemistry; HEK293 Cells; Humans; in-cell target engagement assays; Kinases; Life Sciences & Biomedicine; luminescence; Luminescent Measurements; Nuclear Proteins - antagonists & inhibitors; Nuclear Proteins - metabolism; Optimization; Pharmacology & Pharmacy; Polo-Like Kinase 1; Protein Binding; Protein Serine-Threonine Kinases - antagonists & inhibitors; Protein Serine-Threonine Kinases - metabolism; Proto-Oncogene Proteins - antagonists & inhibitors; Proto-Oncogene Proteins - metabolism; Pteridines - chemistry; Pteridines - metabolism; Pteridines - toxicity; Science & Technology; Transcription Factors - antagonists & inhibitors; Transcription Factors - metabolism; luminescence; bromodomain inhibition; drug design; fluorescence; in-cell target engagement assays; INHIBITOR; SELECTIVITY; epigenetics; BRD4
• ISSN: 1860-7179; 1860-7187
• DOI: 10.1002/cmdc.201600502

Evaluating the engagement of a small molecule ligand with a protein target in cells provides useful information for chemical probe optimization and pharmaceutical development. While several techniques exist that can be performed in a low‐throughput manner, systematic evaluation of large compound libraries remains a challenge. In‐cell engagement measurements are especially useful when evaluating compound classes suspected to target multiple cellular factors. In this study we used a bioluminescent resonant energy transfer assay to assess bromodomain engagement by a compound series containing bromodomain‐ and kinase‐biasing polypharmacophores based on the known dual BRD4 bromodomain/PLK1 kinase inhibitor BI2536. With this assay, we discovered several novel agents with bromodomain‐selective specificity profiles and cellular activity. Thus, this platform aids in distinguishing molecules whose cellular activity is difficult to assess due to polypharmacologic effects. Place your BETs on BRET: Target engagement assays for evaluating small molecules in cells provide valuable information for the development of drugs and probes. Here, a high‐throughput bioluminescence resonance energy transfer assay is used to study bromodomain inhibition. Novel bromodomain‐specific inhibitors are identified from a series of bromodomain‐ and kinase‐binding polypharmacophores whose cellular activity can obscure the pertinent biological target of the compounds.