UMB-32 is a potent, selective inhibitor of the BET bromodomain BRD4 [1]. The BET family (BRD2, BRD3, BRD4, and BRDT) functions as transcriptional coactivator proteins. BET bromodomains are also important mediators of cell cycle progression and facilitate developmental transitions such as spermiogenesis. Deregulation of BET bromodomain function has been observed in numerous malignancies. BET bromodomain inhibition has contributed new insights into gene regulation and emerged as a promising therapeutic strategy in cancer [1].

In vitro: UMB-32 bound to BRD4 with a Kd value of 550 nM and 724 nM cellular potency in BRD4-dependent lines. UMB-32 showed potency against TAF1, a bromodomain-containing transcription factor. UMB-32 showed markedly increased potency for the BET proteins associated with a dramatic improvement in selectivity. UMB-32 potently bound to the TAF1 and TAF1L with the Kd values of 560nM and 1.3 μM, respectively [1].

Reference:
[1] McKeown M R, Shaw D L, Fu H, et al.  Biased multicomponent reactions to develop novel bromodomain inhibitors[J]. Journal of medicinal chemistry, 2014, 57(21): 9019-9027.