Multi-conformational Virtual Screening And Bio-activity Evaluation Of Phosphoinositide 3-kinase Gamma (PI3K?) Inhibitors

Phosphoinositide 3-kinase gamma(PI3K?)plays as a secondary messenger in the body and participates in various cellular activities,including cell survival,proliferation,and metabolism,etc.Besides,since PI3K? is mainly expressed in the hematopoietic system,it has been considered as a promising drug target for the treatment of hematologic tumors and immune-related diseases.Thus,the development of new selective PI3K? inhibitors has gained much attention.However,accumulative studies have revealed that PI3K? shares high homology with other PI3 K isoforms(PI3K?,?,and ?)and most of the residues are conserved in the ATPbinding pockets of these proteins.It makes developing specific PI3K? inhibitors a big challenge.Traditional experimental methods are difficult to distinguish the sub-structural differences.Thus,in this study,our group utilize computer-aided drug design methodologies to demonstrate the subtle structural features of PI3K? and reveal the selective mechanism of PI3K? inhibition at the molecular level.It may provide new ideas for developing novel PI3K? selective inhibitors:(1)By using quantitative structure-activity,molecular docking and molecular dynamic simulations,etc.,the hotspot residues related to the high affinity and selectivity of ligands in the PI3K? active pocket were identified.These structural features would be used to construct a virtual screening model.(2)49 pro-hit compounds were identified through the integrated virtual screening based on multiple PI3K? structures.Several novel chemical entities were identified in subsequent cellfree enzymatic experiments,among which JN-KI3 showed the highest activity.(3)JN-KI3 exhibited a potent PI3K? inhibitory activity(IC50 = 3.87 ?M)in the in-vitro enzymatic experiments;JN-KI3 exhibited a strong anti-proliferative activity towards hematologic malignancies in the in-vitro cellular experiments and JN-KI3 induced the apoptosis of blood tumor cells by inhibiting PI3K-AKT signaling pathway.(4)The selective inhibition mechanism of JN-KI3 for PI3K? was studied by molecular docking and molecular dynamics simulation.In the active pockets of PI3K?,Val882,Ala885,and Thr886,formed hydrogen bonds with JN-KI3,and Met953 and Ile963 formed strong hydrophobic interactions with JN-KI3.It provided valuable guidance for the further structural modifications of JN-KI3.