Nucleolin mediates cell migration and tubule formation. The binding specificity of employed antinucleolin Ab was shown in panel A. Indicated concentrations of Ab were incubated with HMECs to neutralize cell-surface nucleolin, and the assays of cell adhesion (B), cell migration (C), and cell proliferation (D) were performed. Purified rabbit IgG served as a positive control. Neutralizing cell-surface nucleolin significantly inhibited cell migration but only marginally affected cell adhesion and did not affect cell proliferation. Anti-CD71 was employed in cell migration assay as a control. (E) The efficiency of RNAi was detected by immunoblotting, and the reduction of cell-surface nucleolin was quantified by FACS. (F) Knocking down the endogenous nucleolin in HMECs led to apparent reduction of cell migration. (G) Tubule formation of ECV304 on growth factors supplemented Matrigel in response to 20 μg/mL antinucleolin Abs or interfered with their endogenous expression of nucleolin. Bar, 100 μm. *P < .05; ***P < .01.