Eur J Pharmacol. 2020 Oct 10:173651. doi: 10.1016/j.ejphar.2020.173651. Online ahead of print.
α-Conidendrin is a lignan isolated from Taxus wallichiana and other species. In the present study, we demonstrated that α-conidendrin inhibited the cell-surface expression of intercellular adhesion molecule-1 (ICAM-1) induced by tumor necrosis factor-α (TNF-α) at an IC50 value of 40-60 μM in human lung adenocarcinoma A549 cells. α-Conidendrin decreased ICAM-1 protein and mRNA expression levels at concentrations of 40-100 μM in TNF-α-stimulated A549 cells. The TNF-α-induced mRNA expression of vascular cell adhesion molecule-1, E-selectin, and cyclooxygenase-2 was also reduced by α-conidendrin. In the TNF-α-induced nuclear factor-κB (NF-κB) signaling pathway, α-conidendrin did not influence the translocation of the NF-κB subunit RelA from the cytoplasm to the nucleus at concentrations up to 100 μM. A chromatin immunoprecipitation assay revealed that α-conidendrin at 100 μM reduced the binding of RelA to the ICAM-1 promoter in response to a stimulation with TNF-α. Collectively, these results indicated that α-conidendrin interfered with the DNA binding of RelA to the ICAM-1 promoter, thereby reducing ICAM-1 transcription.