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.
Keywords: Angiogenesis; Esculetin; HUVECs; VEGF.