Design, synthesis, and biological evaluation of purine-containing hydrazone derivatives as anticancer agents targeting EGFR and HER2 kinases

Abstract

Cancer represents a major health issue across the world and is identified as the second leading cause of mortality globally. The simultaneous inhibition of epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) tyrosine kinases becomes an efficient strategy in cancer management. The present research focused on designing, synthesising, and biological assessment of a novel purine-hydrazone derivative as a cancer-treating agent that targets EGFR and HER2 tyrosine kinases. Initially, the designed molecules were investigated in silico using molecular docking to assess their predicted binding modes and relative docking scores within the kinase domains of EGFR and HER2. Subsequently, the compounds were synthesised and evaluated in vitro for their antiproliferative activity against multiple cancer cell lines using the MTT assay. The most potent derivatives were then analysed for their kinase inhibitory effects on EGFR and HER2, as well as their ability to induce cell cycle arrest and apoptosis. Among the assessed molecules, 19a, 16b, and 22b displayed considerable antiproliferative efficacy and effectively inhibited both EGFR and HER2 kinases. Compounds 19a, 16b, and 22b showed greater kinase suppression potency against EGFR relative to lapatinib (which showed an IC50 of 0.130 ± 0.002 μM), demonstrating IC50 values of 0.081 ± 0.003, 0.062 ± 0.002, and 0.074 ± 0.002 μM, respectively. (E)-4-((9-cyclopentyl-9H-purin-6-yl) amino)-N'-(3-(trifluoromethyl) benzylidene) benzohydrazide (16b) received further structural modifications to optimise its effectiveness in suppressing cell proliferation and dual inhibition of EGFR/HER2 kinases. Modifying the purine ring at the N9 position by substituting the cyclopentyl moiety with the 3-methylbenzyl group (in compound 16e) resulted in increased anti-proliferative activity on A549, SKOV-3, and SKBR-3 cell lines. Compound 16e displayed EC50 values of 0.64 ± 0.04, 1.93 ± 0.01, and 1.9 ± 0.1 μM, while compound 16b showed less efficacy with EC50 values of 2.6 ± 0.4, 2.0 ± 0.1, and 4 ± 1 μM, respectively. Furthermore, compound 16e exhibited enhanced kinase inhibitory effects towards EGFR compared to 16b, with an IC50 value of 0.024 ± 0.001 μM for 16e and 0.062 ± 0.002 μM for 16b. Additionally, 16e demonstrated substantial activity against HER2, exhibiting an IC50 value of 0.062 ± 0.003 μM. Flow cytometry analysis revealed that compound 16e substantially triggers apoptosis and arrests the cell cycle at the G0/G1 phase in both UFH-001 and A549 cells. Overall, the results of this study highlight compound 16e as a promising anticancer agent, warranting further investigation into its therapeutic potential across diverse cancer types.