Design, synthesis and biological evaluation of new series of hexahydroquinoline and fused quinoline derivatives as potent inhibitors of wild-type EGFR and mutant EGFR (L858R and T790M)

New series of hexahydroquinoline and fused quinoline derivatives were designed and synthesized. The thirty seven new compounds were screened for in vitro antitumor activity against HepG2, HCT-116 and MCF-7 Cancer cells. Results indicated that compounds 2e, 2h, 5b, 5c, 6a, 7d and 9b have the strongest potency against the three Cancer cells, and they were further screened for in vitro cytotoxicity against A431 and H1975 Cancer cells, as well as WI38 and WISH normal cells. Results revealed that 7d potently inhibited the growth of H1975 cells harboring EGFR^T790M mutation (IC₅₀ = 1.32 ± 0.2 µM) over A431 cells overexpressing EGFR^WT (IC₅₀ = 4.96 ± 0.3 µM). Moreover, the seven compounds displayed low cytotoxicity against the tested normal cells. The seven potent antitumor compounds were examined for their ability to inhibit the activity of EGFR^WT. The attained data manifested that 7d has remarkable EGFR^WT inhibitory activity (IC₅₀ = 0.083 ± 0.002 μM) compared to erlotinib (IC₅₀ = 0.067 ± 0.002 μM). Compound 7d was further studied for its enzymatic inhibitory activity against other eight human kinases, and it displayed outstanding inhibitory activity against EGFR^L858R and EGFR^T790M mutants (IC₅₀ = 0.053 ± 0.002, 0.026 ± 0.001 μM, respectively), as well as JAK3 (IC₅₀ = 0.069 ± 0.003 μM). Analysis of cell cycle evidenced that 7d induces cell cycle arrest in G2/M and pre-G1 phases in the tested Cancer cells. In addition, Cancer cell death induced by 7d was proved to take place via Apoptosis supported by elevated Bax/Bcl-2 ratio in the tested Cancer cells. Moreover, docking results confirmed the good binding interactions of 7d with EGFR^WT, EGFR^L858R, EGFR^T790M and JAK3, which came in agreement with the results of in vitro Enzyme assay. Further, 7d is predicted to have good oral absorption, good drug-likeness properties and low toxicity risks in human.