Identification and anti-tumor evaluation of 3-acyl-indol-based 2,4-diarylaminopyrimidine analogues as potent ALK inhibitors capable of overcoming drug-resistant mutants

A series of novel 2,4-diarylaminopyrimidine analogues (G-1∼G-8 and I-1∼I-24) were rationally designed by incorporating 2-alkyl-3-acyl-1H-indol fragment to interact with the hydrophobic region of the intractable ALK^G1202R mutant. Wherein, compound I-24 bearing a 2-methyl-3-dimethylformamido-1H-indol moiety was identified as the most promising ALK inhibitor with IC₅₀ values below 4 nM against ALK^WT, ALK^L1196M and ALK^G1202R, accompanied by concrete down-regulation of phospho-ALK and its relative downstream signaling. Subsequently, I-24 displayed significant anti-proliferative activity in the nanomolar range towards ALK-positive cell lines including a panel of Ba/F3 cells harboring mutational ALK. Dramatically, the involvement of I-24 decreased colony formation and migration tendency on H2228 cells. Meanwhile, flow cytometry analysis indicated that I-24 could induce cell Apoptosis and achieve cell cycle arrest in G1 phase. Notably, oral administration of I-24 at 50 mg/kg regressed tumor in the H2228 xenograft model with tumor growth inhibition value of 93.5%. Collectively, I-24 with favorable PK profile was supposed to further investigation as potent ALK inhibitor to circumvent clinical drug resistance.

2,4-Diarylaminopyrimidine; ALK; Antitumor evaluation; Design & synthesis; G1202R mutant.