Design, synthesis and biological evaluation of dihydroquinoxalinone derivatives as BRD4 inhibitors

BRD4 plays a key role in transcriptional regulation. Recent biological and pharmacological studies have demonstrated that bromodomain-containing protein 4 (BRD4) is a viable drug target for cancer treatment. In this study, we synthesized a series of dihydroquinoxalinone derivatives and evaluated their BRD4 inhibitory activities, obtaining compound 5i with IC50 value of 73nM of binding activity in BRD4(1) and 258nM of cellular activity in MV-4-11 cancer cell lines. Docking studies were performed to explain the structure-activity relationship. Based on its potent biochemical and anti-proliferative activity, the novel BRD4 inhibitor compound 5i, is a promising lead compound for further investigation.