Erk5 knock-down abrogates PEDF anti-angiogenic activity. A, Erk5 knock-down. We used two distinct shRNAmir cloned in pGIPZ lentiviral vectors. Western blot of the total cell lysates showed 70 and 90% knock-down (KO1 and KO2, respectively). KO2 population has been selected for further analysis. B and C, scratch wound assay was performed on confluent endothelial cell monolayer. B, representative images of the scratch wounds at 0 and 6 h are shown and the areas of the wound used for the quantitative measurements are marked. C, rate of the endothelial cell migration into the wound surface was measured as percent wound closure. □, control; ■, 20 nm PEDF. Asterisk indicates statistically significant difference (p < 0.05 by one-way ANOVA).