Notes: YH 239-EE is an ethyl ester prodrug form of YH 239, a potent inhibitor of the p53-MDM2 protein-protein interaction.{52286} YH 239-EE (20 μM) inhibits the growth of OCI-AML-3 cells and halts the cell cycle at the sub-G1 phase and induces apoptosis in NB4 and MOLM-13 cells.