MicroRNA-503 targets FGF2 and VEGFA and inhibits tumor angiogenesis and growth

FGF2 and VEGFA are the two most potent angiogenic factors. Here we report that miR-503 can simultaneously down-regulate FGF2 and VEGFA. The expression of miR-503 is repressed in HCC cells and primary tumors due to a potential epigenetic mechanism. Overexpression of miR-503 reduced tumor angiogenesis in vitro and in vivo. We also found that miR-503 expression was down-regulated by hypoxia through HIF1α. These results identify a miRNA that targets both FGF2 and VEGFA in cancers, demonstrate the anti-angiogenesis role of miR-503 in tumorigenesis, and provide a novel mechanism for hypoxia-induced FGF2 and VEGFA through HIF1α-mediated inhibition of miR-503.