Rational design of pyrazole-oxime hybrids as dual-targeting agents for glioma and breast cancer brain metastasis

To design, synthesize, and biologically evaluate a novel series of 1-(4-chlorophenyl)-2-(4-methylpyrazol-1-yl)ethenone oxime derivatives (5-15) as targeted anticancer agents, focusing on their selectivity for glioma, mechanistic action, and blood-brain barrier (BBB) permeability. The oxime derivatives were synthesized and characterized using ¹H-NMR, ¹³C-NMR, and mass spectrometry. In vitro cytotoxicity was assessed against C6 (glioma), MCF-7 (breast cancer), and SH-SY5Y (human neuroblastoma) cell lines. Flow cytometry evaluated apoptosis and cell cycle arrest for the lead compound. Molecular docking simulations were performed against CDK6 (PDB: 5L2I) and P-glycoprotein/ABCB1 (PDB: 7A6E). All derivatives exhibited selective potency against C6 glioma cells. Compound 14 demonstrated the highest antiproliferative activity (IC₅₀: 31.23 µM) against tumor lines while sparing SH-SY5Y cells. Flow cytometry confirmed that compound 14 triggers apoptosis and induces cell cycle arrest in C6 cells. Molecular docking predicted the most favorable docking scores for compound 14 against both CDK6 and P-glycoprotein. Structure-activity relationships (SAR) analysis validates the 4-methylpyrazole core as a viable scaffold for targeted glioma therapy. These results suggest that further functionalization of the O-alkyl oxime moiety merits further investigation as a starting point for potentially brain-penetrant scaffolds, although in vivo and target-level validation are required.