ABSTRACT
A series of novel noncovalent glycine/ß-alanine anilide derivatives possessing 2-chloronaphthoquinone structure as a pharmacophoric unit were designed, synthesized, and evaluated for their antiproliferative and antiproteasomal activities against MCF-7 cell line, in vitro. According to biological activity results, all the target compounds showed antiproliferative activity in the range of IC50 = 7.10 ± 0.10-41.08 ± 0.14 µM and most of them exhibited inhibitory efficacy with varying ratios against the three catalytic subunits (ß1, ß2, and ß5) presenting caspase-like (C-L), trypsin-like (T-L) and chymotrypsin-like (ChT-L) activities of proteasome. The antiproteasomal activity evaluations revealed that compounds preferentially inhibited the ß5 subunit compared with ß1 and ß2 subunits of the proteasome. Among the compounds, compounds 7 and 9 showed the highest antiproliferative activity with an IC50 value of 7.10 ± 0.10 and 7.43 ± 0.25 µM, respectively. Additionally, compound 7 displayed comparable potency to PI-083 lead compound in terms of ß5 antiproteasomal activity with an inhibition percentage of 34.67 at 10 µM. This compound showed an IC50 value of 32.30 ± 0.45 µM against ß5 subunit. Furthermore, molecular modeling studies of the most active compound 7 revealed key interactions with ß5 subunit. The results suggest that this class of compounds may be beneficial for the development of new potent proteasome inhibitors.
