In addition, FKA functions as a potent cell active NEDDylation inhibitor to induce Cullin1 and Ubc12 deNEDDylation and Skp2 degradation in all tested cancer cell lines that were derived from prostate, breast, renal, liver, lung, colon and cervical cancers, melanoma and osteosarcoma regardless of their genetic background. Here, SKP2 is linked to osteosarcoma.