Development of Fluorescence Imaging Probes for Labeling COX-1 in Live Ovarian Cancer Cells.

Recent experimental evidence demonstrated an aberrant overexpression of cyclooxygenase-1 (COX-1) in various cancers, which has stimulated the development of COX-1-selective inhibitors as promising anticancer drugs and cancer imaging agents. Herein we describe the synthesis and validation of 3-(furan-2-yl)-N-aryl 5-amino-pyrazoles as a novel class of COX-1 inhibitors, including molecular docking studies. Among all tested compounds, 4-(5-azido-3-(furan-2-yl)-1H-pyrazol-1-yl)benzoic 17 displayed a favorable COX-1 inhibition and selectivity profile (COX-1 IC50 = 0.1 μM, SI >1000 over COX-2). Compound 17 was selected as a lead structure for developing the novel COX-1-selective fluorescent probe 22. Fluorescent probe 22 was prepared via click chemistry by installing a nitro-benzoxadiazole motif as a fluorophore into the 3-(furan-2-yl)-N-aryl 5-amino-pyrazole scaffold. Fluorescence probe 22 was tested in ovarian cancer cell line OVCAR-3, confirming its usefulness for targeting and visualizing COX-1 in living cells with confocal microscopy.