Fig. 6

DSF/Cu²⁺ induces proteasome inhibition and apoptosis independent of the CT-like activity. Lysates from CMY cells treated with IC₉₀ doses of DSF/Cu²⁺ (160 nM) or BTZ (5 nM) were prepared at the indicated time points. Western blot analysis was performed using an antibody against ubiquitin (a, upper panel), against PARP (a, middle panel), and Tubulin was used as a loading control (a, lower panel). CT-like activity of CMY cells treated with DSF/Cu²⁺ or BTZ at the concentrations described in (a) was measured at 12 h and plotted as a percent of control (y-axis) against drug treatment (x-axis). BTZ significantly inhibited the CT-like activity compared to DSF/Cu²⁺ and vehicle control (b). The same experiment was performed at 12 h using increasing doses of both BTZ and DSF/Cu²⁺ (c)