Thiadiazole-Derived VEGFR-2 Inhibitors: From Design to Anticancer Evaluation

In this study, a series of novel thiadiazole derivatives (7a, 7b, 9a, 9b, and 9c) were rationally designed as potential VEGFR-2 inhibitors using a pharmacophore-guided strategy. The compounds were synthesized and assessed for their antiangiogenic and anticancer effects. Among them, compound 9b showed the strongest VEGFR-2 inhibition (IC₅₀ = 0.030 ± 0.001 μM), outperforming the reference drug Sorafenib. Cytotoxicity tests revealed that 9b was highly effective against MCF-7 breast cancer cells (IC₅₀ = 8.06 ± 0.7 μM) while exhibiting minimal toxicity toward normal WI-38 cells. Flow cytometry demonstrated that 9b induced significant G2/M cell cycle arrest and increased apoptosis, supported by molecular data showing upregulation of caspase-3 and Bax and downregulation of Bcl-2, indicating activation of the intrinsic apoptotic pathway. Extensive in silico studies-including molecular docking, 200 ns molecular dynamics simulations, interaction mapping, principal component analysis of trajectories, and free energy landscape analysis-confirmed that 9b binds stably and efficiently within the VEGFR-2 active site. Overall, these results highlight compound 9b as a promising VEGFR-2-targeted antiangiogenic agent with potent enzymatic and cellular activity, favorable selectivity, and mechanistic validation through combined experimental and computational approaches.