Fig. 5
Hinokiflavone is a novel CK2 inhibitor. (a) The in vitro inhibitory activity of hinokiflavone against CK2α was assessed by using the service of Reaction Biology Corp. The compound was tested in a 10-dose IC50 mode with a 3-fold serial dilution starting at 100 µM in the presence of 10 µM ATP. Data are represented as the percentage of kinase activity relative to the control group. (b) Effect of hinokiflavone on the phosphorylation of CK2 substrates in N/P(14) cells. Cells were treated with hinokiflavone for 24–48 h and analyzed by western blot using an antibody against the consensus sequence of CK2 substrates ((pS/pT)DXE). (c) Docking pose of hinokiflavone in the binding site of CK2α. Hinokiflavone is composed of two flavonoid units, labeled as flavonoid A and flavonoid B. Hydrogen bonds are shown as green dashed lines (d–f) N/P(14) cells were exposed to various concentrations of hinokiflavone (HNK) for 24–48 h and subjected to western blot analysis by using indicated antibodies. M: protein marker. The band intensities of each protein were quantified using ImageJ software and normalized to that of GAPDH. Fold changes compared to the control (0) group are expressed as the mean±S.D. (n = 3). One-way ANOVA with Dunnett’s multiple comparison was used to evaluate statistical significance.
