Figure 4

Increasement in the proteasome activity following co-treatment with ALA + BOZ is concentration-dependent and correlates with the results on the cell viability. The effect of bortezomib (BOZ) and its combinations with antioxidants on the chymotrypsin-like activity of the proteasome in A2058 (A) and in U266 (B) cells. Cells were treated with therapeutic agents as indicated for 24 h. The data were normalized to the control wells. Data are given as mean values ± standard deviation (SD), (n = 3). A2058 (C,E) or U266 cells (D,F) were treated as indicated and then the relative H₂O₂ level of the cells was determined. The data are normalized to the control wells. Mean ± SD (n = 2). The levels of significance are shown as follows: x: P < 0.05; y: P < 0.01; z: P < 0.001, determined by the One-way ANOVA test followed by Fishers LSD post hoc test.