Figure 3

Enhanced endogenous ROS up-regulate glycolytic activity. (a) Quantification of ROS levels in SMMC-7721 cells in comparison with their XO-transfected cells. SMMC-7721 cells were transfected with a void vector (XO-) or a vector expressing XO (XO+) as described in "Materials and methods". In some cases XO+ cells were treated with 5 mM α-LA for 24 h. ROS levels were measured by DCF fluorescence using flow cytometry as described in "Materials and methods". Data were expressed relative to control SMMC-7721 cells (XO-). (b) Enhanced XO expression caused an elevated protein level of HIF1-α and HK2. In some cases XO+7721 cells were treated with 5 mM α-LA for 24 h. XO, HIF1-α and HK2 protein levels were assessed by Western blot as described in "Materials and methods". The present blots are representative of three experiments. (c) Comparison of glycolytic enzymes activity (LDH activity) in SMMC-7721(XO-) and XO-transfected 7721 cells (XO+). LDH activity levels are expressed relative to control SMMC-7721 cells (XO-). * P < 0.05 versus 7721 cells (XO-) in the absence of α-LA treatment (a, c); **, P < 0.05 versus XO+7721 cells in the absence of α-LA treatment (a). Columns: means ± S.D. of four independent experiments.