Structure-based modification of ortho-amidophenylaminopyrimidines as a novel mutant EGFR inhibitor against resistant non-small cell lung cancer

Abstract

The challenge of acquired drug resistance in patients with epidermal growth factor receptor (EGFR)-mediated non-small cell lung cancer (NSCLC) has not been overcome, especially the tertiary C797S mutation of EGFR. Herein, it was reported the structure-based design of ortho-amidophenylaminopyrimidines as new mutant EGFR (EGFRL858R/T790M/C797S and EGFRL858R/T790M) inhibitors (type I‒II). Among them, target Ⅱd exhibited the strongest activity against EGFRL858R/ T790M/C797S (IC50=5.51 nM) and EGFRL858R/T790M (IC50=33.35 nM) kinases, and suppressed Ba/F3 cells harboring EGFRL858R/ T790M/C797S and EGFR19Del/T790M/C797S mutants with IC50 values of 0.433 μM and 1.485 μM, respectively. In particular, compared with Ⅰb (IC50=3.656 μM) which was the best inhibitor of type I, Ⅱd (IC50=0.442 μM) displayed enhanced antiproliferative effect against gefitinib-resistant H1975 cells harboring the EGFRL858R/T790M mutation. Ⅱd also demonstrated promising EGFRL858R/T790M/C797S mutant selectivity, and was 70-fold less potent against the wild type EGFR. In addition, Ⅱd behaved low toxicity against the normal human liver cells L02, which was 28-fold less potent. Moreover, both DAPI staining and apoptosis assays demonstrated that Ⅱd induced apoptosis in the resistant H1975 cells. Cycle assays showed that Ⅱd arrested the cell cycle at the G2/M phase. Western blot analysis revealed that Ⅱd suppressed phosphorylation of the EGFR and the downstream signaling ERK1/2 level in NSCLC cells. Hence, these results suggested that Ⅱd might be useful as a potent mutant EGFR inhibitor and was effective in both third- and fourth-generation EGFR-mutant NSCLC, the activity would not be limited by the C797S mutation for further development in the treatment of resistant NSCLC.