Angiogenin negatively regulates the expression of basic fibroblast growth factor (bFGF) and inhibits bFGF promoter activity.

Research focused on angiogenin and basic fibroblast growth factor (bFGF) was expected to identify means to inhibit tumor growth and metastasis. However, interactions exist between the two angiogenic factors, and the overall mechanism is still not clear. To explore the mechanism by which angiogenin regulates the expression of bFGF, RT-PCR and western blot were performed to analyze bFGF expression. Nuclear translocation of angiogenin was investigated by immunofluorescence staining and immune electron microscopy. Site-directed mutagenesis, reporter gene assays, and electrophoretic gel mobility shift assay (EMSA) were applied to investigate the promoter activity. The results showed that angiogenin negatively regulates bFGF expression in HeLa cells. Angiogenin undergoes nuclear translocation, and an angiogenin binding site (CTCTCTCT) on the bFGF promoter was identified. bFGF promoter activity was inhibited by angiogenin. Angiogenin and bFGF are two potent and representative angiogenesis factors, that play an important role in tumor angiogenesis and development. These mechanisms guide us to further investigate the effect of angiogenin and bFGF on tumor growth and development. IJCEP