Quinoxaline-based scaffolds as dual VEGFR-2/EGFR kinase inhibitors and apoptotic inducers: Design, synthesis,...

Dual inhibition of the epidermal growth factor receptor (EGFR) and vascular endothelial growth factor receptor-2 (VEGFR-2) represents an effective strategy for achieving synergistic antitumor activity by simultaneously suppressing tumor proliferation and angiogenesis. In this study, a series of quinoxaline-based derivatives (7-15) was rationally designed, synthesized, and biologically evaluated as dual EGFR/VEGFR-2 inhibitors. In vitro cytotoxicity screening against breast (MCF-7), liver (HepG2), and colon (HCT116) cancer cell lines identified compounds 9, 11, 12, and 13 as the most potent antiproliferative agents, exhibiting activities comparable to or exceeding those of the reference drugs Sorafenib and Erlotinib. Among them, compound 12 demonstrated the highest potency, as evidenced by cellular fold inhibition values of 0.288 and 0.227 against EGFR and VEGFR-2, respectively. Enzymatic assays further confirmed its strong inhibitory activity, with IC₅₀ values of 0.06 μM (EGFR) and 0.204 μM (VEGFR-2), comparable to Erlotinib (0.052 μM) and Sorafenib (0.131 μM). Mechanistic investigations revealed that compound 12 exhibited interesting selectivity, with 2.4-fold lower cytotoxicity toward normal MCF10A cells compared to doxorubicin. It induced a pronounced G2/M phase arrest in MCF-7 cells and significantly promoted apoptosis, resulting in a 12-fold increase in apoptotic cell population. Gene expression analysis indicated activation of both intrinsic and extrinsic apoptotic pathways, demonstrated by a marked increase in the Bax/Bcl-2 ratio (∼20-fold) and upregulation of caspase-9 (7.9-fold) and caspase-8 (2.9-fold). Molecular docking studies supported the experimental findings, revealing a strong binding affinity of compound 12 within the active sites of EGFR and VEGFR-2. Molecular dynamics simulations further confirmed the stability of these interactions over time. Additionally, in silico ADME profiling demonstrated good drug-likeness, fulfilling Lipinski, Veber, Egan, and Muegge criteria. Collectively, these findings highlight compound 12 as a promising dual EGFR/VEGFR-2 inhibitor with significant potential for further development as a multitarget anticancer candidate.