CS-6 inhibited the phosphorylation and activation of IKKβ. (A) Human A549 cells were treated with CS-6 at the indicated doses. At 48 h after treatment, the IKKβ, p-IKKβ, IκBα and p-IκBα proteins were analyzed by Western blotting. (B) The best ranked pose of CS6 in the ATP binding site of IKKβ generated with docking. (Left) Interactions of CS6 and IKKβ are delineated by ribbon structure, Hydrogen bonds are displayed as yellow dashed lines, and the participating amino acid residues are marked. (Right) MOLCAD representation the molecular lipophilic potential surface upon the bioactive pose of CS6 in the ATP binding site of IKKβ. The blue denotes the hydrophilic, brown for the lipophilic and green corresponds to the neutral moiety. (C) Cytoplasmic and nuclear extracts were prepared for the Western blot analysis of p-p65, p65 and p50. GAPDH and TFIIB were used as controls for sample loading. (D) A549 cells were treated with CS-6 (50 nM) after pretreatment with CB (50 nM). The IKKβ, and p-IKKβ proteins were analyzed by Western blotting.