In silico design and bioevaluation of selective benzotriazepine BRD4 inhibitors with potent antiosteoclastogenic activity

• Published in: Chemical biology & drug design Vol. 90; no. 1; pp. 97 - 111
• Main Authors: Deepak, Vishwa, Wang, Binglin, Koot, Dwayne, Kasonga, Abe, Stander, Xiao Xing, Coetzee, Magdalena, Stander, Andre
• Format: Journal Article
• Language: English
• Published: HOBOKEN Wiley 01.07.2017
• Subjects: Actin Cytoskeleton - drug effects; Amino Acid Sequence; Animals; Binding Sites; Biochemistry & Molecular Biology; Cell Differentiation - drug effects; Chemistry, Medicinal; Crystallography, X-Ray; Drug Design; Humans; Life Sciences & Biomedicine; Lipopolysaccharide Receptors - metabolism; mechanism‐based drug design; Mice; Molecular Docking Simulation; molecular modeling; Monocytes - cytology; Monocytes - drug effects; Monocytes - metabolism; Nuclear Proteins - antagonists & inhibitors; Nuclear Proteins - metabolism; Osteoclasts - cytology; Osteoclasts - drug effects; Osteoclasts - metabolism; Osteogenesis - drug effects; Pharmacology & Pharmacy; Protein Structure, Tertiary; RAW 264.7 Cells; Science & Technology; structure‐based drug design; Thermodynamics; Transcription Factors - antagonists & inhibitors; Transcription Factors - metabolism; Triazines - chemistry; Triazines - metabolism; Triazines - pharmacology; structure-based drug design; MOLECULAR-DYNAMICS; HIGH-THROUGHPUT; DISCOVERY; BONE-RESORPTION; BET; REGULATOR; mechanism-based drug design; molecular modeling; CARBONIC-ANHYDRASE-II; OPTIMIZATION; UPDATE; OSTEOCLAST DIFFERENTIATION
• ISSN: 1747-0277; 1747-0285
• DOI: 10.1111/cbdd.12930

The bromodomain (BRD) and extra‐terminal domain (BET) protein family bind to acetylated histones on lysine residues and act as epigenetic readers. Recently, the role of this protein family in bone loss has been gaining attention. Earlier studies have reported that benzotriazepine (Bzt) derivatives could be effective inhibitors of BET proteins. In this study, using in silico tools we designed three Bzt analogs (W49, W51, and W52). By docking, molecular simulations, and chemiluminescent Alpha Screen binding assay, we show that the studied analogs were selective at inhibiting BRD4 when compared to BRD2. Furthermore, we tested the effectiveness of these analogs on osteoclast formation and function. Among the examined analogs, Bzt‐W49 and Bzt‐W52 were found to be the most potent inhibitors of osteoclastogenesis without cytotoxicity in murine RAW264.7 osteoclast progenitors. Both the compounds also inhibited osteoclast formation without affecting cell viability in human CD14+ monocytes. Moreover, owing to attenuated osteoclastogenesis, actin ring formation and bone resorptive function of osteoclasts were severely perturbed. In conclusion, these results suggest that the novel BRD4‐selective Bzt analogs designed in this study could be explored further for developing therapeutics against bone loss diseases characterized by excessive osteoclast activity. Benzotriazepine bromodomain 4 inhibitors capable of inhibiting osteoclast differentiation without cytotoxic effects on murine RAW264.7 osteoclast progenitors, as well as human CD14+ monocytes, were in silico designed and synthesized. This study demonstrates that in silico docking and molecular dynamics simulations are useful to identify BRD inhibitors with a particular selectivity profile. Furthermore, the compounds identified in this study have remarkable antiosteoclastogenic potential and warrant further studies for drug development against bone loss diseases characterized by excessive osteoclast activity.