Eugenol suppresses the proliferation and invasion of TNF-α-induced fibroblast-like synoviocytes via regulating NF-κB and COX-2.

Eugenol (4-allyl -2- methoxyphenol), reportedly, a native compound that widely exists in a variety of plants, shows diverse biological activities such as anti-bacteria, anti-inflammation and anti-oxidation. This work was to delve into the effects and molecular mechanisms of eugenol on the phenotypes of fibroblast-like synovial cells from rheumatoid arthritis (RA). Fibroblast-like synovial cells treated with tumor necrosis factor-α (TNF-α) for 24 h received eugenol treatment. In this study, we found eugenol could inhibit TNF-α-induced proliferation, migration, invasion, angiogenesis and inflammatory response of fibroblast-like synovial cells, and promote apoptosis. Eugenol's target genes were significantly associated with vascular endothelial growth factor (VEGF) and NF-kappaB (NF-κB) signaling pathway. Eugenol reversed the promoting effect of TNF-α on the expression of NF-κB signaling pathway-related proteins as well as prostaglandin-endoperoxide synthase 2 (PTGS2, also known as COX-2) protein. In addition, the NF-κB pathway inhibitor Bay11-7082 markedly restrained the viability, migration, aggressiveness, and angiogenic and inflammatory responses of TNF-α-induced fibroblast-like synovial cells and promoted apoptosis. In conclusion, eugenol may represent a novel drug to suppress the progression of RA by inhibiting NF-κB signaling pathway and COX-2 expression in fibroblast-like synovial cells.