Transwell migration assay

Cell migration was assayed using a Transwell chamber (8 µm, 12 wells). A total of 1×10⁴ cells in serum-free DMEM were transferred to the upper compartment of the well inserts and the cells were cultured for 24 h at 37°C. Meanwhile, the lower compartment was filled with complete DMEM (10% FBS). After 24 h, the cells on the top surface of the membrane were wiped off softly with a cotton swab and the cells that migrated to the bottom of the membrane were fixed with methanol and were stained with 5% crystal violet for 10 min at room temperature and were visualized using a Leica DC 300F microscope (magnification, ×400).