MG132 + DOX induces potential mitochondrial membrane loss. U937 cells were cultured and treated with MG132 (1 μM), DOX 1 μM, or MG132 + DOX. After 24 h, the cells were harvested and the ΔΨm was assessed by flow cytometry using DIOC6 staining. Protonophore Cyanide m-chorophenylhydrazone (CCCP) was used as a positive control. Representative histograms of each treatment are displayed. For each sample, at least 20,000 events were acquired in a FACSAria-I cell sorter and the data were analyzed with FACSDiva software. The graph shows the results as mean ± the Standard deviation (SD) of three independent experiments performed in triplicate. Statistical analysis, the Mann–Whitney U test. *p <0.05 all groups vs the Untreated control group (UGC); ●p <0.05 MG132 + DOX vs all groups.