Figure 6

MG132 treatment prevented the inhibition of HIF-1α expression by DCPA. DU145 (A) and PC-3 (B) cells were cultured in serum-free MEM basal medium with Earle's salt in the presence of 0, 75, or 150 μM DCPA for 24 h, followed by the treatment with or without 10 μM of MG132 for 30 min. Cells were incubated with or without 10% fetal bovine serum for 6 h. Total cellular protein extracts were prepared from these cells, and aliquots of the extracts (30 μg) were used for the immunoblotting analysis using antibodies against HIF-1α and HIF-1β.