GSK973 is a highly selective and orally bioavailable inhibitor that targets the second bromodomains (BD2s) of the BET family. It exhibits a pIC 50 of 7.8 and a pK d of 8.7 specifically for BRD4 BD2. Additionally, GSK973 demonstrates a remarkable selectivity of 1600-fold for BRD4 BD2 over BRD4 BD1. Moreover, it displays good potency against BRD2 BD2, BRD3 BD2, and BRDT BD2, with pIC 50 ranging from 7.4 to 7.8 and pK d ranging from 8.3 to 8.5.
SRX3212 is a Novel BRD4 PI3Kα inhibitor, displaying an IC50 of 3.7 nM toward BRD4BD1 and 32 nM toward BRD4BD2, and therefore was~65-fold more potent inhibitor of BRD4BD1 and~48-fold more potent inhibitor of BRD4BD2 than SF2523 (GLXC-10641), retaining its high inhibitory activity for PI3Kα (IC50: 22 nM).