Notes: NEDD8 inhibitor M22 is an inhibitor of NEDD8-activating enzyme (NAE).{65669} It inhibits NEDDylation of ubiquitin-conjugating enzyme 12 (UBC12) in a cell-free assay using recombinant human NAE in a concentration-dependent manner. NEDD8 inhibitor M22 selectively inhibits NEDDylation over SUMOylation and ubiquitination in A549 non-small cell lung cancer (NSCLC) cells and inhibits the growth of A549 cells (GI50 = 5.5 µM). It inhibits tumor growth in an AGS gastric adenocarcinoma mouse xenograft model when administered at a dose of 60 mg/kg.