Figure 1

COX deficiency enhances susceptibility to H₂O₂-induced cell death. (a) List of utilized chemical inhibitors of the mitochondrial RC. Inhibition of individual RC complexes in HeLa cells was quantified by a reduction in oxygen consumption (left panel). Cytotoxicity was quantified by trypan-blue exclusion after 48 h (right panel). (b) Analysis of cell death by trypan-blue exclusion in HeLa cells treated for 24 h with individual RC complex inhibitors as indicated and subjected to H₂O₂ for further 24 h. (c) Analysis of cell death by trypan-blue exclusion in 143B_ΔCOX cybrid cells and COX10^−/− fibroblasts subjected to H₂O₂ for 20 h. The error bars in panel a and c represent the mean±S.D. (n=3), the error bars in panel b represent the mean±S.D. (n=6), two-tailed unpaired t-test. *P <0.05, ***P<0.001