Herein, we report the discovery and characterization of a novel class of PAK4 inhibitors with a quinazoline scaffold. Based on the shape and chemical composition of the ATP-binding pocket of PAKs, we chose a 2,4-diaminoquinazoline series of inhibitors as a starting point. Guided by X-ray crystallography and a structure-based drug design (SBDD) approach, a series of novel 4-aminoquinazoline-2-carboxamide PAK4 inhibitors were designed and synthesized. The inhibitors’ selectivity, therapeutic potency, and pharmaceutical properties were optimized. One of the best compounds, 31 (CZh226), showed remarkable PAK4 selectivity (346-fold vs PAK1) and favorable kinase selectivity profile. Moreover, this compound potently inhibited the migration and invasion of A549 tumor cells by regulating the PAK4-directed downstream signaling pathways in vitro. Taken together, these data support the further development of 31 as a lead compound for PAK4-targeted anticancer drug discovery and as a valuable research probe for the further biological investigation of group II PAKs.

A series of novel oleanolic acid coupled 1,2,3-triazole derivatives have been designed and synthesized by employing a Cu(I) catalyzed Huisgen 1,3-dipolar cycloaddition reaction. The anti-proliferative evaluation indicated that some compounds exhibited excellent anti-cancer activity against the examined cancer cell lines. Among all derivatives, compound 3t possesses the best inhibitory activity against HT1080 cells. A series of pharmacology experiments show that compound 3t significantly induced HT1080 cell apoptosis. Therefore, this compound can serve as a promising lead candidate for further study.