Chrysin suppresses IL-6-induced angiogenesis via down-regulation of JAK1/STAT3 and VEGF: an in vitro and in ovo approach.

Chrysin, 5,7-dihydroxyflavone, possesses many biologic properties. This study aimed to investigate the effects and molecular mechanisms of chrysin on IL-6-induced angiogenesis in vitro and in ovo. Chicken chorioallantoic membrane assay, an in ovo angiogenesis assay, showed chrysin significantly suppressed IL-6-induced neovascularization. Furthermore, chrysin significantly suppressed human umbilical vein endothelial cell (HUVECs) migration and tube formation. The signaling pathway involved in chrysin-related antiangiogenesis was also investigated. The data indicated that chrysin is able to down-regulate the expression of glycoprotein 130 (gp130), soluble IL-6 receptor (IL-6R), phosphorylated JAK1 and STAT3, and VEGF in HUVECs. The IL-6-induced binding of STAT3 was significantly suppressed by chrysin. Moreover, chrysin did not further suppress VEGF expression with STAT3 knocked down. Taken together, the results show that chrysin suppresses IL-6-induced angiogenesis through modulation of the sIL-6R/gp130/JAK1/STAT3/VEGF signaling pathway. Chrysin may provide new therapeutic potential for IL-6-induced pathological angiogenesis.