Figure 4.

Effect of TTFA and 3NP, two complex II inhibitors with different target specificities. (a) Time- and dose-dependent pro-apoptotic effects by TTFA or 3NP. HeLa cells were treated with the indicated concentrations of TTFA or 3NP. After incubation, apoptotic cells were quantified by flow cytometry using PI staining of the sub-G1 population. (b) Effects of TTFA and 3NP on SQR and SDH activities. (Top panel) HeLa cells were treated for 8 h with TTFA (0.5 mM) or 3NP (1 mM). Mitochondria were isolated and SQR and SDH activities were assessed by specific assays. (Bottom panel) Isolated mitochondria were treated by the indicated concentrations of TTFA immediately before the appropriate enzymatic assay. ^*P<0.05 compared with the related control; ^#P<0.05