HIF1A and hepatocellular carcinoma: Pretreatment with the proteasome inhibitor MG-132 prevented the ability of 32-134D to block HIF-1α and HIF-2α protein accumulation (Figure 7D), indicating that 32-134D induced proteasomal degradation of HIF-1α subunits in MIO-M1 cells, as previously described for Hep3B human hepatocellular carcinoma cells (44).