VEGFR-1-dependent migration and invasion of MDA-MB-231 and MCF-7 cells.

(A) Western blot analysis of VEGFR-1 expression in MDA-MB-231 and MCF-7 cells transfected with a shRNA against VEGFR-1. VEGFR-1 expression was significantly decreased in both MDA-MB-231 (left) and MCF-7 cells (right) expressing VEGFR-1-shRNA. The bar graph shows the relative protein expression levels among groups. β-actin was used as a loading control. Data are presented as average ± s.d. for three independent experiments. *P<0.05. (B) VEGFR-1 activation increased the migration of MDA-MB-231 and MCF-7 cells in vitro. PlGF induced a 3-fold increase in migration of MDA-MB-231 cells and at least a 4-fold of MCF-7 cells compared with the controls. Reduction of VEGFR-1 expression inhibited the PlGF-mediated migration of MDA-MB-231 and MCF-7 cells. (C) VEGFR-1 activation increased the invasion of MDA-MB-231 and MCF-7 cells in vitro. PlGF induced a 1.5-fold increase in invasion of MDA-MB-231 and 5-fold of MCF-7 cells compared with the controls. Decreased VEGFR-1 expression blocked the PlGF-mediated invasion of MDA-MB-231, but not in MCF-7 cells. Data are presented as average ± s.d. for three independent experiments. *P<0.05.