Esculetin Inhibits VEGF-Induced Angiogenesis Both In Vitro and In Vivo

Esculetin is known to inhibit tumor growth, but its effect in angiogenesis has not been studied. Here, we report the efficacy of esculetin on VEGF-induced angiogenesis. Esculetin treatment inhibited VEGF-induced proliferation and DNA synthesis of HUVECs with no cell toxicity. G1-phase cell-cycle arrest was associated with a decreased expression of cyclins and CDKs via the binding of p27KIP1. Esculetin down-regulated the MMP-2 expression in VEGF-stimulated HUVECs, which suppressed colony tube formation and migration. Esculetin reduced the phosphorylation of VEGFR-2 and the downstream signaling of VEGFR-2, including ERK1/2 and eNOS/Akt pathways. Esculetin suppressed microvessel outgrowth from an aortic ring ex vivo model treated with VEGF, and blocked the VEGF-induced formation of new blood vessels and hemoglobin content in an in vivo Matrigel plug model. Collectively, VEGF-stimulated responses in angiogenesis were inhibited in vitro and in vivo, providing a theoretical basis for effective use against anti-angiogenic therapies.