5-Fluorouracil (5-FU)-based Aza-Michael addition product: A selective carbonic anhydrase IX inhibitor

Abstract

A new 5-fluorouracil (5-FU) derivative (3) has been obtained by Aza-Michael addition reaction between 5-FU and acrylonitrile. The structure of the compound was elucidated by multi spectroscopic (viz. FT-IR, 1H NMR, MS) techniques, and the solid-state structure was confirmed by single-crystal X-ray studies. Enzyme inhibition studies revealed that compound (3) shows selectivity and high inhibition potential towards carbonic anhydrase IX (CAIX) compared to carbonic anhydrase II (CAII). Fluorescence binding assay showed that compound (3) possesses a high binding affinity for CAIX with a dissociation constant (Kd) = 0.86 μM. Further, compound (3) decreases the viability of HepG2 and HeLa cancer cell lines more effectively in hypoxic conditions than normoxic. For HeLa and HepG2 cells, the estimated IC50 values of compound (3) in normoxic conditions are 19.39±1.23 μM and 26.89±1.89 μM, whereas, in hypoxic conditions, the IC50 significantly decreases to 10.93±1.44 μM and 18.16±1.62 μM, respectively, suggesting the CAIX specific activity of compound (3). The experimental findings were corroborated by molecular docking and molecular dynamics (MD) simulation studies, which indicated that the compound (3) forms a more stable complex with CAIX than CAII. Overall, the present study suggested that compound (3) stands as a potential lead molecule for synthesizing anticancer molecules.