The CURN caused down-regulation of ICAM-1 expression in TNF-α-stimulated A549 is mediated by inhibition of AP-1 activation.

<p>(A) Nuclear extracts prepared from untreated cells or from cells with or without 24 h pretreatment with 50 µM CURN or CURH and then incubated with 30 ng/ml TNF-α for 1 h were tested for (A) AP-1 and NF-κB DNA binding activity by EMSA. (B, C) Cells were pretreated with Tanshinone II A(AP-1 inhibitor) and Bay117082 (NF-κB inhibitor) for 1 h, and then incubated with 30 ng/ml TNF-α for 24 h. The levels of ICAM-1 protein were determined by Western blot. (D) Cells were pretreated with 50 µM CURN, CURH or 10 µM DPI for 1 h, and then incubated with 30 ng/ml TNF-α for 30 min. The levels of phosphorylation of c-jun and c-fos were determined by Western blot. Representative results from three separate experiments are shown. The data are expressed as a fold of the control value and are the means±SEM for three separate experiments. GAPDH was used as the loading control.