Nifedipine inhibits activation of transcription factor NF-κB

Abstract

This study was performed to examine the effects of the calcium channel blockers, nifedipine, amlodipine, diltiazem, and verapamil on the activation of the transcription factor NF-κB. A549 cells, a human epithelium-like lung carcinoma cell line, were transfected with the NF-κB reporter plasmid, which contains the luciferase gene driven by promoters containing a TATA element and 5 copies of the κB cis-acting element, and co-transfected with 0.2 μg of pSV2neo vector using LipofectAMINE. Nifedipine significantly decreased the expression of luciferase protein stimulated with IL-1β (1ng/mL) compared with controls: 80±4% at 3 μmol/L, 47±2% at 10 μmol/L and 30±2% at 30 μmol/L (each, n=3, p<0.0001). The inhibitory effect of nifedipine on promoter activity was concentration-dependent, with a maximal effect obtained at 30 μmol/L. In contrast, high concentrations (30 μmol/L) of amlodipine, diltiazem or verapamil decreased promoter activity to only 89±3%, 90±3% or 87±2% of control, respectively. A comparable inhibitory effect of nifedipine was observed when cells were stimulated with tumor necrosis factor (TNF)-α (50 ng/mL), or phorbol 12-myristate 13-acetate (PMA, 100 ng/mL). Electrophoretic mobility shift assay by lipopolysaccharide stimulation, using the RAW 264.7 macrophage cell line, also showed inhibition of NF-κB activation by nifedipine in concentrations of 30 and 50 μmol/L. Nifedipine possesses the unique property of inhibiting NF-κB, which may be independent of its calcium channel blocking activity, and may, in part, explain its immunosuppressive effect.