FIGURE 3.

DPG regulates NF-κB activity in glioblastoma cell lines by miR16- and miR146a-mediating IRAK2 and TRAF6 down-expression. U87MG (A) and T98G (B) cell lines were transfected with the NF-κB-luciferase reporter and incubated with dipotassium glycyrrhizinate (DPG) for 40 h. Equal amounts of cell extract were assayed for dual-luciferase activity. The reporter activity was observed as down-regulated by DPG when comparing with untreated transiently transfected cells. Transiently transfected cells were also treated with dehydroxymethylepoxyquinomicin (DHMEQ) or lipopolysaccharide (LPS). As expected, DHMEQ and LPS down-regulates and induces NF-κB reporter activity, respectively, in both cell lines. DPG significantly increases miR16 and miR146a expression in U87MG (P = 0.004 and P = 0.003, respectively) (C) and T98G (P = 0.01 and P = 0.006, respectively) cell lines. (D) Instead, DPG decreases IRAK2 and TRAF6 mRNA levels in U87MG (P = 0.26 and P = 0.02, respectively) and (E) T98G (P = 0.01 and P = 0.005, respectively) cells. (F) Data represent means and standard deviations of a representative experiment performed in triplicate. Statistics were performed in a two-tailed t-test with P ≤ 0.05.