Migration and Invasion Assays

For migration assay, cells were prepared as a suspension of 1×105 cells/mL in serum-free medium. A 24-well culture plate was used as the lower chamber, and a transwell chamber was used as the upper chamber. A total of 600 µL of culture medium containing 20% fetal bovine serum was added to each well of the lower chamber, and 100 µL of the cell suspension was added to the upper chamber. The culture plate was placed in an incubator for 24 hours, and then the lower chamber was washed. The chamber was immersed in paraformaldehyde for 30 minutes at room temperature and rinsed. After staining with 0.1% crystal violet for 10 minutes and rinsing, photographs were taken under a microscope. The number of cells was counted in three random fields, and the average number of migrated cells was calculated. Invasion assay was basically the same as migration assay except the chamber was percolated with matrigel.