The roles of NF-κB in homocysteine-induced COX-2 mRNA expression and PGE
secretion. (A) COX-2 mRNA and (B) PGE2 expression were determined in human primary monocytes and U937 cells pretreated with NF-κB inhibitors PDTC and SN50, and then stimulated with 200 μg/mL homocysteine for 2 h. All bar graphs represent folds of CL monocytes, mean ± SEM of three individual experiments. *P < 0.05 versus CL. #P < 0.05 versus DMSO-treated cells with homocysteine stimulation. (C) and (E) NF-κB activation was determined by TF ELISA assays in U937 cells treated with homocysteine only (C) and both homocysteine and PD98059/SP600125 (E). *P < 0.05 versus CL. (D) The phosphorylation of IκB was determined by Western blotting. (F) ChIP assays were performed for NF-κB using p65 antibody. The results shown are representative of three independent experiments with similar results.