Rational design of hybrid hydrazide–hydrazone/thiourea derivatives as potential VEGFR-2 targeting anticancer agents: synthesis, biological evaluation, and mechanistic insights into anticancer activity

The development of novel anticancer agents capable of modulating pathways associated with tumor progression remains a critical strategy, particularly for aggressive breast cancer subtypes such as triple-negative breast cancer (TNBC). In this study, a new series of hydrazide–hydrazone/thiourea derivatives (MIH-31-46) was rationally designed, synthesized, and evaluated as potential anticancer agents targeting vascular endothelial growth factor receptor-2 (VEGFR-2). Structural characterization was performed using 1H NMR, 13C NMR, and HR-MS. The antiproliferative activities of the synthesized derivatives were assessed against MCF-7 and MDA-MB-231 breast cancer cell lines, along with non-cancerous L929 cells. Several compounds exhibited moderate cytotoxicity, with MIH-36 emerging as the most promising candidate, demonstrating dual activity against both cancer cell lines and improved selectivity. Functional assays revealed that MIH-36 significantly inhibited cell migration and induced apoptosis in both models. Mechanistic investigations revealed increased VEGFR-2 mRNA expression, accompanied by reduced surface VEGFR-2 levels, suggesting possible interference with VEGFR-2-associated signaling through feedback regulation and receptor internalization. Molecular docking and molecular dynamics simulations supported the experimental findings, indicating strong binding affinity of MIH-36, MIH-38, and MIH-44 toward VEGFR-2, particularly in its inactive (DFG-out) conformation, suggesting a potential type II inhibitor-like binding profile. Stable interactions with key residues, such as Cys919, Glu885, and Asp1046, along with favorable binding free-energy profiles, further support their potential as VEGFR-2-targeting compounds. Overall, this study identifies MIH-36 as a promising lead compound with a multifaceted anticancer activity profile, associated with reduced proliferation, migration, and survival of breast cancer cells, potentially through modulation of VEGFR-2-associated pathways. These findings provide a valuable framework for further optimization and development of hydrazide–hydrazone/thiourea-based VEGFR-2-targeted therapeutics.