Figure 6.

PTEN and ERK are essential for the protective role of vitamin D. (A) vitamin D downregulated the expression of PTEN and upregulated the phosphorylation of Akt after AR-insult. However, with the addition of LY294002, the expression of p-p70S6K could not be obviously reduced by vitamin D. Relative PTEN (B), p-Akt (C), and p-p70S6K (D) levels were determined by densitometry and normalized to GAPDH or each total protein levels. (E) Western blot showing decrease in the expression of Beclin-1 when hepatocytes were transfected with Beclin-1 targeting siRNA. (F) Results of the CCK-8 assay showing a significant protective effect of vitamin D on hepatocytes while U0126, LY294002, and Beclin-1 siRNA treatment caused an aggravation of cell viability in spite of vitamin D presence. (G) DCFH-DA fluorescence measurements of cellular ROS levels showed significantly lower ROS level in vitamin D group compared with that in control group. However, this reduction was reversed by U0126, LY294002, and Beclin-1 siRNA treatment, respectively.