Novel quinoxaline derivatives as promising cytotoxic agents: structure-based design, in silico studies, VEGFR-2...

Newly developed compounds based on a 3-methyl-2-oxoquinoxaline core bearing either acetohydrazide, benzohydrazide, or acetamide substituents 7-16 were rationally designed, synthesized, and evaluated for their cytotoxic potential via VEGFR-2 inhibition and targeting of the PI3K/AKT/mTOR signaling pathway. The compounds were screened against five human cancer cell lines (HL-60, PC-3, HepG-2, MCF-7, and A549), with PC-3 cells demonstrating the highest activity. Among the tested derivatives, compounds 10 and 15 exhibited the highest cytotoxic activity against HL-60 (IC₅₀ = 0.803 ± 0.02 and 1.619 ± 0.05 μM) and PC-3 (IC₅₀ = 3.047 ± 0.14 and 3.506 ± 0.11 μM) cells, compared to the reference drug sorafenib. Both compounds showed reduced cytotoxicity toward normal human lung fibroblasts (WI38), indicating a more favorable safety profile. Further studies confirmed their VEGFR-2 inhibitory activity (compound 10: IC₅₀ = 0.139 ± 0.005 μM; compound 15: IC₅₀ = 0.291 ± 0.01 μM). Western blot results displayed compound 10's notable inhibition of the PI3K/AKT/mTOR axis. Apoptosis and cell cycle assays demonstrated that compound 10 induced late apoptosis and necrosis, leading to sub-G1 phase accumulation in PC-3 cells. Molecular docking and pharmacophore modeling indicated key interactions with VEGFR-2similar to sorafenib, while 100 ns molecular dynamics simulations showed that compound 10 maintained a stable and extensive binding network. ADMET predictions supported the drug-likeness and safety of these compounds. Collectively, the results support the promising potential of these quinoxaline derivatives as orally bioavailable VEGFR-2 inhibitors with significant antiproliferative effects against prostate cancer via targeting of PI3K/AKT/mTOR signaling.