Rationally designed quinazolinone derivatives incorporating acetyl pyridine and thiazole scaffolds as dual EGFR/HER-2 anticancer agents: integrated biological evaluation, molecular profiling, and advanced computational studies.

Given the well-established anticancer relevance of quinazolinone scaffolds, rational hybridization with acetyl pyridine and thiazole moieties was employed to investigate the impact of electronic and steric modulation on the biological activity of the resulting derivatives. Accordingly, a novel series of quinazolin-4-one hybrids (1a-4b) was synthesized through thiazolo-quinazolinone (series a) and pyridinylacetylquinazolin-4-one (series b) pathways, and their structures were confirmed by IR, 1H/13C NMR, mass spectrometry, and elemental analyses. Antiproliferative evaluation against HeLa and MDA-MB-231 cell lines using the MTT assay revealed that compounds 2b and 3a exhibited the highest cytotoxic activities, with 2b showing superior potency (IC50 = 3.87 ± 0.2 and 3.01 ± 0.6 μM, respectively) and high selectivity toward cancer cells (SI = 22.27-28.63). Both compounds were further evaluated as dual EGFR/HER-2 inhibitors, where 2b displayed the strongest inhibitory activity (IC50 = 0.08 and 0.137 μM, respectively), with preferential EGFR inhibition. Flow cytometry analysis demonstrated that 2b induced significant G1/S phase arrest and apoptosis through BAX and caspase-3 upregulation and CCND1 downregulation. Additionally, 2b markedly inhibited cancer cell migration, reducing wound closure from 94.81% to 62.96%. In silico ADMET profiling indicated favorable oral drug-likeness for both 2b and 3a, with zero Lipinski violations, high intestinal absorption, and no predicted BBB penetration. Molecular docking revealed strong binding affinities of 2b toward EGFR and HER-2 (-10.28 and -9.44 kcal/mol, respectively) through multiple hydrogen-bonding and hydrophobic interactions, while 3a showed weaker binding due to altered binding orientation. Molecular dynamics simulations confirmed stable accommodation of 2b within both EGFR and HER-2 active sites, with the HER-2-2b complex exhibiting enhanced structural stability and persistent hydrogen-bond interactions throughout the 100 ns simulation. DFT studies further revealed high electronic reactivity with a low HOMO-LUMO energy gap (0.307 eV). Collectively, these findings identify compound 2b as a promising dual EGFR/HER-2-targeted anticancer lead.