The anti-malaria agent artesunate inhibits expression of vascular endothelial growth factor and hypoxia-inducible factor-1 alpha in human rheumatoid arthritis fibroblast-like synoviocyte

Increasing evidence indicates that the anti-malarial agent artemisinin and its derivatives may exert anti-angiogenic effect. In the present study, we explored the effect of artesunate, a artemisinin derivative, on TNF alpha- and hypoxia-induced expression of hypoxia inducible factor-1 alpha (HIF-1 alpha) and secretion of vascular endothelial growth factor (VEGF) and inteleukin-8 (IL-8) in human rheumatoid arthritis fibroblast-like synoviocytes (RA FLS), and further investigated the signal mechanism by which this compound modulates HIF-1 alpha, VEGF and IL-8 expression. RA FLS obtained from patients with active rheumatoid arthritis were pretreated with artesunate, and then stimulated with TNF alpha and hypoxia. Production of VEGF and IL-8 was measured by ELISA. Nuclear location of HIF-1 alpha was measured by confocal fluorescence microscopy. HIF-1 alpha and other signal transduction proteins expression was measured by Western blot. Artesunate decreased the secretion of VEGF and IL-8 from TNF alpha- or hypoxia-stimulated RA FLS in a dose-dependent manner. Artesunate also inhibited TNF alpha- or hypoxia-induced nuclear expression and translocation of HIF-1 alpha. We also showed that artesunate prevented Akt phosphorylation, but did not find evidence that phosphorylation of p38 and ERK was affected. TNF alpha- or hypoxia-induced secretion of VEGF and IL-8 and expression of HIF-1 alpha were hampered by treatment with the PI3 kinase inhibitor LY294002, suggesting that inhibition of PI3 kinase/Akt activation might inhibit VEGF and IL-8 secretion and HIF-1 alpha expression induced by TNF alpha or hypoxia. Our results suggest that artesunate inhibits angiogenic factor expression in RA FLS, and provide novel evidence that, as a low-cost agent, artesunate may have therapeutic potential for RA.