Design, synthesis, antiproliferative assessments, and computational studies of new quinolin-2(1H)-ones as dual EGFR/HER-2 inhibitors

Compound <b>5a</b> exhibited the most potent antiproliferative profile, particularly against MCF-7 breast cancer cells (IC₅₀ = 34 nM), outperforming erlotinib (IC₅₀ = 40 nM). Kinase inhibition assays further confirmed dual activity of <b>5a</b>, with IC₅₀ values of 87?nM and 33?nM against EGFR and HER-2, respectively. Compound <b>5a</b> induced apoptosis via activation of caspase-3, -8, and -9, along with upregulation of Bax, downregulation of Bcl-2, and increased cytochrome c release. Flow cytometry analysis demonstrated that <b>5a</b> caused significant G0/G1 phase arrest in MCF-7 cells, indicating a cytostatic mechanism of action. Computational studies provided structural validation of the observed biological activities. Molecular docking studies showed a strong binding affinity <b>5a</b> within the ATP-binding pockets of EGFR and HER-2, supported by key hydrogen bonding and hydrophobic interactions. These findings were further corroborated by 100 ns molecular dynamics simulations, which confirmed the structural stability and compactness of the <b>5a</b>-HER-2 complex, as evidenced by low RMSD, consistent RMSF, and favorable radius of gyration and potential energy profiles. Additionally, ADME predictions revealed that <b>5a</b> possesses favorable physicochemical and pharmacokinetic properties. Density Functional Theory (DFT) calculations provided insights into the electronic structure of <b>5a</b>, highlighting favorable HOMO-LUMO distribution and electrostatic potential surfaces that support its dual-binding behavior.