USP22 and hepatocellular carcinoma: Reduction of ZEB1 caused by knockdown of USP22 was also prevented by MG132, on the other hand, USP22 depletion accelerated ZEB1 degradation with the treatment of cycloheximide (CHX), which is protein synthesis inhibitor, in HCC-derived cells (Fig. 4D–F and Supplementary Fig. S5A).