DVL2 and hepatocellular carcinoma: We then treated HCC cells with the proteasome inhibitor MG132 (10 mM) for 1 h and found that the Dvl2 protein level in the CYP2E1-overexpressing cells was significantly restored (Fig. 4E), suggesting that the Dvl2 decrease in CYP2E1-overexpressing HCC cells may involve a ubiquitin-dependent pathway.