Discovery of potent and selective PI3Kδ inhibitors bearing amino acid fragments.

The selective inhibition of PI3Kδ is a potential therapeutic strategy for the treatment of hematologic malignancies. Herein, we report a series of compounds bearing amino acid fragments as potent and selective PI3Kδ inhibitors. Among them, compound A10 exhibited sub-nanomolar PI3Kδ potency. In cellular assays, A10 achieved strong antiproliferation against SU-DHL-6 cells, and caused cell cycle arrest, and induced apoptosis in SU-DHL-6 cells. The docking study showed that A10 tightly bound to PI3Kδ protein with a planar-shaped conformation. Collectively, compound A10 represented a promising potent and selective PI3Kδ inhibitor bearing amino acid fragement albeit with moderate selectivity over PI3Kγ but superior selectivity against PI3Kα and β. This study suggested that using the amino acid fragments instead of the pyrrolidine ring is new strategy for design of potent PI3Kδ inhibitors.