AM 114, a derivative of boronic chalcone, is a potent small-molecule inhibitor of the proteasome that inhibits the chymotrypsin-like activity of the 20S proteasome, with a value of 50% inhibition concentration IC₅₀ of approximately 1 μM, resulting in a significant accumulation of ubiquitinated p53 and other cellular proteins in whole cells without significantly disrupting the interaction of p53 and murine double minute 2 (mdm2) proteins. AM 114 also exerts anti-cancer activity against cancer cells, which potently inhibits the growth of human colon cancer HCT116 cells with values of IC₅₀ of 1.5 μM and 0.6 μM in MTT and colony formation assays respectively.

Reference

Achanta G, Modzelewska A, Feng L, Khan SR, Huang P. A boronic-chalcone derivative exhibits potent anticancer activity through inhibition of the proteasome. Mol Pharmacol. 2006 Jul;70(1):426-33. Epub 2006 Apr 24.