Design, synthesis and antitumor activity of 4-arylamine substituted pyrimidine derivatives as noncovalent EGFR inhibitors overcoming C797S mutation

Clinical researches have shown that epidermal growth factor receptor (EGFR) is a key target for treatment of non-small cell lung cancer (NSCLC). Many EGFR inhibitors were successfully developed as ani-tumor drugs to treat NSCLC patients. Unfortunately, drug resistances were found in clinic. To overcome C797S mutation in EGFR, a novel series of 4-arylamine substituted pyrimidine derivatives were designed and synthesized under the principle of structure-based drug design. Interestingly, compounds 6e and 9i demonstrated the best anti-proliferative activity against A549, NCI-H1975, and HCC827 cells. In particular, the IC50 values against HCC827 cells reached to 24.6 nM and 31.6 nM, which were much lower than human normal cells 2BS and LO2. Furthermore, compounds 6e and 9i showed extraordinary activity against EGFR19del/T790M/C797S (IC50 = 16.06 nM and 37.95 nM) and EGFRL858R/T790M/C797S (IC50 = 11.81 nM and 26.68 nM), which were potent than Osimertinib (IC50 = 52.28 nM and 157.60 nM). Further studies have shown that compounds 6e and 9i could pertain inhibition of HCC827 colony formation, and arrest HCC827 cells at G2/M phase. Moreover, the most promising compound 6e could inhibit the migration of HCC827 cells, induce HCC827 cells apoptosis, and significantly inhibit the phosphorylation of EGFR, AKT and Erk1/2. In vivo xenograft mouse model with HCC827 cells, compound 6e resulted in remarkable tumor regression without obvious toxicity. In addition, molecular docking studies suggested that compound 6e could firmly combine with T790M-mutant, T790 M/C797S-mutant, and L858R/T790 M/C797S-mutant EGFR kinases as ATP-competitive inhibitor.