Inhibition of angiogenesis in human endothelial cell using VEGF specific nanobody.

Angiogenesis is an important step in tumor development and metastasis. Vascular endothelial growth factor (VEGF) plays an important role in progression of angiogenesis. VEGF121 and VEGF165 are the most relative forms of VEGF family which contain the full biological activity. Nanobodies derived from camelidae are the smallest biding site of antigen. Unique characteristic of nanobodies make them as a useful candidate for research. In this report, we describe the isolation of VEGF specific nanobodies from dromedaries immunized with purified VEGF antigen using phage display. Four clones that showed the highest signal value in ELISA experiment were selected and expressed as a His-tagged fusion protein. Four selected nanobodies were reacted strongly to VEGF in cross-reactivity assay. The binding affinity of selected nanobodies named Nb22, Nb23, Nb35 and Nb42 were differed from 0.1 to 60nM. The nanobodies inhibited endothelial cell proliferation or tube formation in response of VEGF in a dose-dependent manner. These results indicate the potential of nanobodies in inhibition of VEGF and represent a promising candidate for cancer research and therapeutics.