Figure 2. Bortezomib-induced inhibition of proteasome activities in parental and bortezomib-resistant HCC cells.

Chymotrypsin-, caspase- and trypsin-like activities were determined using intact cells after treatment with a concentration range of bortezomib for 24 h. Proteasome activities were normalized to untreated cells, which were set at 100%. Bortezomib-resistant cells (right panel) required higher bortezomib concentrations for proteasome inhibition comparable with the parental cells. All results represent the mean ± SEM of at least three experiments.