Bicyclic 2-aminopyrimidine derivatives as potent VEGFR-2 inhibitors and apoptosis Inducers: Structure-Guided design, synthesis, anticancer assessment, and in-silico exploration

Anticancer therapy focuses on VEGFR-2 inhibition to disrupt angiogenesis, a critical process that sustains tumor growth and metastasis. This study outlines the synthesis and biological evaluation of 14 newly designed compounds featuring a bicyclic 2-amino-pyrimidine scaffold. In-vitro VEGFR-2 inhibition showed that compounds 55 and 61 were more potent with IC₅₀ of 0.035 μM and 0.043 μM respectively, compared to the reference drug Sorafenib, and revealed selectivity for VEGFR-2 over EGFR. Consequently, 55 and 61 displayed good antiproliferative activities against the tested cell lines A549 (IC₅₀ = 2.67 and 2.71 μM, respectively) and HCT116 (IC₅₀ = 10.87 and 12.17 μM, respectively). The most active compounds were further assessed for their ability to induce apoptosis and preferential effect on wound closure in A549 cells, investigated via the cell scratch assay. Moreover, these compounds substantially reduced the phosphorylation of ERK and AKT, two downstream targets of VEGFR-2. The CAM assay further verified the antiangiogenic potential of lead compounds, revealing a significant reduction of neovascularization. Molecular docking studies performed for compound 55 showed hydrogen bond interactions with Asp1046, Cys919, and Glu885, similar to FDA-approved sorafenib. Moreover, a 100 ns MD simulation confirmed the complex's stability, while other analyses, such as RMSD, RMSF, PCA, and FEL, were performed to characterize protein conformational variations. Thorough SAR analysis, along with findings of cytotoxic activities and in-vitro inhibition of VEGFR-2, supports the potential of these synthetic compounds as VEGFR-2 inhibitors.