Structure-Based Discovery of Quinazolin-2-amine Derivatives as Potent ROR1 Pseudokinase Inhibitors with In Vitro and In Vivo Efficacy against Triple-Negative Breast Cancer

As a kind of pseudokinase, although ROR1 lacks the ATP catalytic activity similar to that of classical kinases, it has been proven to play a crucial role in the occurrence and development of triple-negative breast cancer (TNBC). Through structure-based drug design strategy, we have discovered novel quinolin-2-amine ROR1 inhibitor 59 which exhibited excellent binding activity to ROR1 (KD = 0.052 μM) and antiproliferative against breast cancer cells in vitro (IC50 = 0.075 μM) while maintaining good selectivity through kinase profiling screening. Mechanistic studies confirmed 59 could induce cell apoptosis and suppresses ROR1 phosphorylation. In vivo experiments in mice have demonstrated that compound 59 could significantly inhibit the growth (TGI = 92.1% at 20 mg/kg) and metastasis of tumors, moreover 59 showed no significant toxicity. Although the oral bioavailability is relatively low, the overall results confirm that compound 59 can serve as a potential candidate for the treatment of TNBC.