1 × 105 cells were plated onto 24-well cell chambers (pore size: 8 μm). The cells were plated in medium without serum, and medium with 20% serum was used as a chemoattractant. The cells were incubated at 37°C for 16 h. Cells in 10 random fields of view at 100× magnification were counted. Images were acquired using an inverted phase-contrast microscope at 100× magnification. (A) Images from the Trans-well migration assays of A549, H1975 and PC9 cells transfected with indicated plasmids (× 100). (B) Statistical results for the trans-well migration assays of A549, H1975 and PC9 cells transfected with indicated plasmids (analyzed by t-tests); %migration = [mean number of cells invading the membrane/mean number of cells migrating through the control insert membrane] × 100. *p < 0.05; **p < 0.01; ***p < 0.001.