Discovery of (<i>S</i>)-2-(1-(4-Amino-3-(3-fluoro-4-methoxyphenyl)-1<i>H</i>-pyrazolo[3,4-<i>d</i>]pyrimidin-1-yl)propyl)-3-cyclopropyl-5-fluoroquinazolin-4(3<i>H</i>)-one (IHMT-PI3Kδ-372) as a Potent and Selective PI3Kδ Inhibitor for the Treatment of Chronic Obstructive Pulmonary Disease
Feng Li, Xiaofei Liang, Zongru Jiang, Aoli Wang, Junjie Wang, Cheng Chen, Wenliang Wang, Fengming Zou, Ziping Qi, Qingwang Liu, Qingwang Liu, Zhenquan Hu, Jiangyan Cao, Hong Wu, Beilei Wang, Li Wang, Jing Liu, Qingsong Liu, Qingsong Liu
Abstract
Accumulated pieces of evidence have shown that PI3Kδ plays a critical role in chronic obstructive pulmonary disease (COPD). Using a fragment-hybrid approach, we discovered a potent and selective PI3Kδ inhibitor (S)-18. In the biochemical assay, (S)-18 inhibits PI3Kδ (IC50 = 14 nM) with high selectivity over other class I PI3Ks (56∼83 fold). (S)-18 also achieves good selectivity over other protein kinases in the kinome (S-score (35) = 0.015). In the cell, (S)-18 selectively and potently inhibits the PI3Kδ-mediated phosphorylation of AKT T308 but not other class I PI3K-mediated signaling. Additionally, (S)-18 exhibits no apparent inhibitory effect on CYP isoforms except for a moderate effect on CYP2C9. Furthermore, it shows no apparent inhibitory activity against hERG (IC50 > 10 μM). In vivo, (S)-18 displays favorable PK properties for inhaled delivery and improves lung function in a rodent model of pulmonary inflammation. These results suggest that (S)-18 might be a new potential therapeutic candidate for COPD.