Effects of the indolocarbazole 3744W on the tyrosine kinase activity of the cytoplasmic domain of the platelet-derived growth factor beta-receptor

PKIS deep dive yields a chemical starting point for dark kinases and a cell active BRSK2 inhibitor

The Published Kinase Inhibitor Set (PKIS) is a publicly-available chemogenomic library distributed to more than 300 laboratories by GlaxoSmithKline (GSK) between 2011 and 2015 and by SGC-UNC from 2015 to 2017. Screening this library of well-annotated, published kinase inhibitors has yielded a plethora of data in diverse therapeutic and scientific areas, funded applications, publications, and provided impactful pre-clinical results. GW296115 is a compound that was included in PKIS based on its promising selectivity following profiling against 260 human kinases. Herein we present more comprehensive profiling data for 403 wild type human kinases and follow-up enzymatic screening results for GW296115. This more thorough investigation of GW296115 has confirmed it as a potent inhibitor of kinases including BRSK1 and BRSK2 that were identified in the original panel of 260 kinases as well as surfaced other kinases that it potently inhibits. Based on these new kinome-wide screening results, we report that GW296115 is an inhibitor of several members of the Illuminating the Druggable Genome (IDG) list of understudied dark kinases. Specifically, our results establish GW296115 as a potent lead chemical tool that inhibits six IDG kinases with IC50 values less than 100 nM. Focused studies establish that GW296115 is cell active, and directly engages BRSK2. Further evaluation showed that GW296115 downregulates BRSK2-driven phosphorylation and downstream signaling. Therefore, we present GW296115 as a cell-active chemical tool that can be used to interrogate the poorly characterized function(s) of BRSK2.

THP-1 and Dictyostelium Infection Models for Screening and Characterization of Anti-Mycobacterium abscessus Hit Compounds

!!NCR1!! presents a great challenge to antimycobacterial therapy due to its innate resistance against most antibiotics. M. abscessus is able to grow intracellularly in human macrophages, suggesting that intracellular models can facilitate drug discovery. Thus, we have developed two host cell models: human macrophages for use in a new high-content screening method for M. abscessus growth and a Dictyostelium discoideum infection model with the potential to simplify downstream genetic analysis of host cell factors. A screen of 568 antibiotics for activity against intracellular M. abscessus led to the identification of two hit compounds with distinct growth inhibition. A collection of 317 human kinase inhibitors was analyzed, with the results yielding three compounds with an inhibitory effect on mycobacterial growth, strengthening the notion that host-directed therapy can be applied for M. abscessus.