VEGF-C increased SiHa cell migration and invasion and induced actin cytoskeleton remodeling. (A) Cells were treated with VEGF-C (100 ng/mL) for 24 or 48 h and cell migration was assayed. SiHa cells were scraped out of the cell culture dish and the extent of migration of the remaining cells was assayed. The upper black lines indicate the starting line and the lower black lines indicate the mean migration distance. (B) Migrating cell numbers were measured and data representing the migration cell numbers from the starting line are expressed as mean ± SD. * = P < 0.05 vs. 24 h control; ** = P < 0.01 vs. 48 h control. (C) Cells were treated with VEGF-C (100 ng/mL) for 24 or 48 h. Cell invasion was assayed using invasion chambers. Invading cells were counted in three different central fields of triplicate membranes and invasion indexes are shown. ** = P < 0.01 vs. control. (D) SiHa cells were treated with VEGF-C (100 ng/mL) for 6 h, 12 h, 24 h or 48 h alone, or treated with VEGF-C for 48 h in the presence of Flt-4/IgG (100 ng/mL). Immunofluorescent analysis of Texas Red-phalloidin (in red) revealed the spatial modifications of actin fibres and the formation of specialized cell membrane structures. Green, white and yellow arrows indicate lamellipodia, pseudopodia and focal adhesion complexes, respectively. Nuclei were counterstained in blue. All the experiments were repeated three times with consistent results, and a representative result is shown.