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Publication Abstract from PubMed

Bromodomains have been pursued intensively over the past several years as emerging targets for the devel-opment of anti-cancer and anti-inflammatory agents. It has recently been shown that some kinase inhibitors are able to potently inhibit the bromodomains of BRD4. The clinical activities of PLK inhibitor BI-2536 and JAK2-FLT3 inhibitor TG101348 have been attributed to this unexpected poly-pharmacology, indicating that dual-kinase/bromodomain activity may be advantageous in a therapeutic context. However, for target validation and biological investigation, a more selec-tive target profile is desired. Here we report that benzo[e]pyrimido-[5,4-b]diazepine-6(11H)-ones, versatile ATP-site di-rected kinase pharmacophores utilized in the development of inhibitors of multiple kinases including a number of previ-ously reported kinase chemical probes, are also capable of exhibiting potent BRD4-dependent pharmacology. Using a dual kinase-bromodomain inhibitor of the kinase domains of ERK5 and LRRK2, and the bromodomain of BRD4 as a case study, we define the structure-activity relationships required to achieve dual kinase/BRD4 activity as well as how to di-rect selectivity towards inhibition of either ERK5 or BRD4. This effort resulted in identification of one of the first report-ed kinase-selective chemical probes for ERK5 (JWG-071), a BET selective inhibitor with 1 muM BRD4 IC50 (JWG-115), and additional inhibitors with rationally designed polypharmacology (JWG-047, JWG-069). Co-crystallography of seven representative inhibitors with the first bromodomain of BRD4 demonstrate that distinct atropisomeric conformers rec-ognize the kinase ATP-site and the BRD4 acetyl lysine binding site, conformational preferences supported by rigid dock-ing studies.

Structural and atropisomeric factors governing the selectivity of pyrimido-benzodiazipinones as inhibitors of kinases and bromodomains.,Wang J, Erazo T, Ferguson FM, Buckley DL, Gomez N, Munoz-Guardiola P, Dieguez-Martinez N, Deng X, Hao M, Massefski W, Fedorov O, Offei-Addo NK, Park PM, Dai L, DiBona A, Becht K, Kim ND, McKeown MR, Roberts JM, Zhang J, Sim T, Alessi DR, Bradner JE, Lizcano JM, Blacklow SC, Qi J, Xu X, Gray NS ACS Chem Biol. 2018 Aug 13. doi: 10.1021/acschembio.7b00638. PMID:30102854^[3]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.