SiRNA or lentivirus transfected cells were seeded in 6-well plates and cultured until reached 100% confluence. Then, sterile pipette tips were used to make scratches across the cell monolayer and the photographs of scratched areas were taken. 24 h later, different scratched areas were selected in each well and were photographed under inverted microscope (Nikon, Tokyo, Japan). The cells protruding from the border of the scratches were counted.