Figure 3. Inhibition of HIF-1α protein accumulation by mitomycin C is not due to an effect on protein degradation.

(a) HEK293 cells were treated with 200 µM desferrioxamine (DFO) and 10 µg/ml mitomycin C for 10.5 hours, as indicated, in the absence or presence of the 26S proteasome inhibitors epoxomicin (1 µM) or lactacystin (5 µM). (b) The cells were pretreated with 200 µM desferrioxamine for three hours, followed by addition of 10 µg/ml mitomycin and 40 µM cycloheximide for 8 hours.