1,2,3,4,6-penta-O-galloyl-β-D-glucose up-regulates heme oxygenase-1 expression by stimulating Nrf2 nuclear translocation in an extracellular signal-regulated kinase-dependent manner in HepG2 cells

Figure 2 Effects of PGG-induced HO-1 on t-Bt-HP-induced toxicity in HepG2 cells. A: Cells transiently transfected with HO-1 siRNA were pre-incubated with indicated concentrations of PGG for 12 h, and exposed to 100 µmol/L t-Bt-HP for 4 h; B: Cells (WT) were transiently transfected with control vector (Vector) or HO-1 gene (HO-1), and then exposed to 100 µmol/L t-Bt-HP for 4 h in the absence or presence of 20 µmol/L ZnPP; C: Cells were exposed to 100 µmol/L of t-Bt-HP for 4 h in the absence or presence of indicated concentrations of bilirubin (BR). Data are expressed as mean ± SE of five independent experiments.