The Anti-Angiogenesis Effect Of A New Flavonoid((2S)-8-isopentenyl-7,2',4'-trihydroxy-5-methoxyflavo-none) And Its Mechanism

Angiogenesis is a complex physiological and pathological process that includes activation of endothelial cells by growth factors, followed by enzymatic degradation of basement membrane, detachment of endothelial cells from adhesion proteins, endothelial cells migration into the perivascular spaces and proliferation, and finally new vessels formation. Flavonoids are signaling molecules, intermediates and metabolites of plant polyphenolic compounds with a wide range of complex structure. They have important significance on treatment of human tumor and cardiovascular diseases, as wide pharmacological activity and low toxicity. In this study, we conducted detailed studies to explore the effect of a new flavoiioid(2S)-8-isopentenyl-7,2',4'-trihydroxy-5-methoxyflavonone(SF-45) on angiogenesis and its mechanism.Results:(1) SF-45 exhibited no inhibitory effect on endothelial cells (EcV304) proliferation under 10μg/ml treatment, whereas promoted cell proliferation slightly (p<0.05) under 20μg/ml,.However SF-45 exhibited the inhibition effect under 30,40 and 50μg/ml. (2) Low concentrations (10,20,30μg/ml) of SF-45 had no effect on migration of EcV304 cells, while higher concentrations (40 and 50μg/ml) of SF-45 remarkably inhibited cell migration. (3) SF-45 significantly inhibited ECV304 cell adhesion in a concentration-dependent manner.10μg/ml of SF-45 had obviously induced cell adhesion, and the maximal effect achieved at 50μg/ml. (4) SF-45 significantly inhibited the tube formation in a concentration-dependent manner.10 and 20μg/ml of SF-45 obviously inhibited tube formation, and the maximal effect achieved at 30,40 and 50μg/ml. (5) SF-45 also exhibited antiangiogenesis effect in vivo, gave a less degree of thickness and density of blood vessels compared to control in chicken chorillantoic membrances experiment. (6) 10μg/ml of SF-45 had no effect on the intracellular ROS level. However, high concentration of SF-45 (20,30,40 and 50μg/ml) could obviously reduce ROS generation in ECV304 cells. (7) SF-45 down-regulated VEGF expression without concentration-dependent manner.10μg/ml of SF-45 obviously inhibited the expression of VEGF, and it reached inhibitory the maximal effect at 20μg/ml. However, the inhibition effect under 30,40,50μg/ml treatment had no remarkably difference with 20μg/ml. (8) SF-45 arrested ECV304 cell cycle in G1 phase.Conclusions:(1) According to the inhibitory effect on endothelial cell proliferation, migration, adhesion and tube formation in vitro, and the antiangiogenesis effect in CAM test, we concluded that SF-45 exhibited antiangiogenesis effect both in vitro and in vivo. (2) The mechanism might relate to its antioxidative activity, which further resulted in the inhibition of ROS-associated VEGF expression. On the whole, many diseases, such as cancer, chronic inflammation and diabetes, are dependent on angiogensis, so these diseases may benefit from therapeutic inhibiton of angiogensis. While in many ischemic diseases, such as ischemic coronary artery diseases, critical limb ischemia and brain infarction, angiogensis may be favorable to improve these diseases. The results of the present study suggested that SF-45 is worth to undergo the further study as a potential new drug candidate of anti-angiogenesis.