Design, synthesis and biological evaluation of novel indole derivatives as potential HDAC/BRD4 dual inhibitors and anti-leukemia agents.

HDAC inhibitors and BRD4 inhibitors were considered to be potent anti-cancer agents. Recent studies have demonstrated that HDAC and BRD4 participate in the regulation of some signal paths like PI3K-AKT. In this work, a series of indole derivatives that combine the inhibitory activities of BRD4 and HDAC into one molecule were designed and synthesized through the structure-based design method. Most compounds showed potent HDAC inhibitory activity and moderate BRD4 inhibitory activity. In vitro anti-proliferation activities of the synthesized compounds were also evaluated. Among them, 19f was the most potent inhibitor against HDAC3 with IC value of 5 nM and BRD4 inhibition rate of 88% at 10 μM. It was confirmed that 19f could up-regulate the expression of Ac-H3 and reduce the expression of c-Myc by western blot analysis. These results indicated that 19f was a potent dual HDAC/BRD4 inhibitor and deserved further investigation.