Aspirin-inspired acetyl-donating HDACs inhibitors.

Aspirin is one of the oldest drugs for the treatment of inflammation, fever, and pain. It is reported to covalently modify COX-2 enzyme by acetylating a serine amino acid residue. By virtue of aspirin's acetylating potential, we for the first time developed novel acetyl-donating HDAC inhibitors. In this study, we report the design, synthesis, in silico docking study, and biological evaluation of acetyl-donating HDAC inhibitors. The exposure of MDA-MB-231 cells with compound 4c significantly promotes the acetylation of α-tubulin and histone H3, which are substrates of HDAC6 and HDAC1, respectively. In silico docking simulation also indicates that compound 4c tightly binds to the deep substrate-binding pocket of HDAC6 by coordinating the active zinc ion in a bidentate manner and forming hydrogen bond interactions with Ser531 and His573 amino acid residues. In particular, compound 4c (GI50  = 147 μM) affords the significant enhancement of anti-proliferative effect on MDA-MB-231 cells, compared with its parent compound 2c (GI50  > 1000 μM) and acetyl-donating group deficient compound 6 (GI50  = 554 μM). Overall, compound 4c presents a novel strategy for developing acetyl-donating HDAC inhibitors.