Insulin Regulates Glucose Consumption and Lactate Production through Reactive Oxygen Species and Pyruvate Kinase M2
Figure 1
Insulin promoted MDA production, glucose consumption and lactate production through ROS production in hepatocellular carcinoma cells. (a) HepG2 cells were seeded in a 12-well plate at 8 × 104 cells/well and cultured at 37°C for 24 h. The cells were then incubated in serum-free medium for 24 h, followed by the pretreatment with catalase (1500 U/mL) for 1 h. CM-H2DCFDA (5 μM) was added and incubated with the cells for 10 min. Cells were then stimulated with insulin (200 nM) for 10 min. The cells were washed thrice with 1x PBS. The representative images were captured with a fluorescence microscope. Bar, 50 μm. (b) Levels of ROS fluorescence signals were quantified by ImageJ; ** compared with that of the same cell line treated without insulin and catalase; ## compared to the cells treated with insulin alone. (c) HepG2 and Bel7402 cells were cultured in serum-free medium overnight. Then, the cells were treated with catalase (1500 U/mL) for 1 h, followed by insulin treatment (200 nM) for 12 h. The proteins were collected and subjected to MDA analysis. Data were presented by mean ± SD (). ** Significant difference compared with that of the same cell line treated or without insulin and catalase (); # and ## significant difference compared to the cells treated with insulin alone ( and , resp.). (d) and (e) HepG2 cells and Bel7402 cells were seeded in 24-well plates and cultured in serum-free medium for 24 h, followed by the treatment with catalase (1500 U/mL) for 1 h. Cells were then stimulated with insulin (200 nM) for 12 h. The medium was collected, and the glucose consumption and lactate production levels were analyzed. Data were mean ± SD from three independent experiments. ** and * compared with that of the same cell line treated without insulin and catalase; # and ## compared to the cells treated with insulin alone.
