Indirubin derivative E804 inhibits angiogenesis

The anti-angiogenic effects of IDR-E804 were examined by assessing the proliferation, migration and capillary tube formation of HUVECs were induced by vascular endothelial growth factor (VEGF) with or without various concentrations of IDR-E804. The inhibitory effect of IDR-E804 angiogenesis and tumor growth in vivo was also investigated in Balb/c mice subcutaneously transplanted with CT-26 colon cancer cells.IDR-E804 significantly decreased proliferation, migration and tube formation of vascular endothelial growth factor VEGF-treated HUVECs. These effects were accompanied by decreased phosphorylation of VEGF receptor (VEGFR)-2, AKT and extracellular signal regulated kinase in VEGF-treated HUVECs. Intratumor injections of IDR-E804 inhibited the growth of subcutaneously inoculated CT-26 allografts in syngenic mice. Immunohistochemistry revealed a decreased CD31 microvessel density index and Ki-67 proliferative index, but an increased apoptosis index in IDR-E804-treated tumors.These data revealed that IDR-E804 is an inhibitor of angiogenesis and also provide evidence for the efficacy of IDR-E804 for anti-tumor therapies.