Figure 6

Berberine increased p21 protein expression through induction of FOXO3a and p53 protein expressions. A-B, A549 cells were exposed to increased concentration of BBR for 24 h, followed by measuring the protein expression of p21 and cyclin D1 by Western blot. The bar graphs represent the mean ± SD of p21/β-actin or cyclinD1/β-actin of three independent experiments. C-D, A549 cells were transfected with control or p53 or FOXO3a siRNAs (50 nM each) for 24 h prior to exposure of the cells to 25 μM BBR for an additional 24 h. Afterwards, Western blot analysis were used measure the protein levels of p53, FOXO3a and p21 using corresponding antibodies. E, Cells were transfected with control (pEGFP-N1) or FOXO3a expression vector (FOXO3a-pEGFP) for 24 h before exposing the cells to BBR for an additional 24 h. Afterwards, the expression of p21 protein was detected by Western blot. The bar graphs represent the mean ± SD of p21/β-actin of three independent experiments. *indicates significant difference from control (P < 0.05).