Migration and Invasion Assays for Cells

For migration detection, after transfection for 24 h, cells (3 × 10⁵/mL) were cultured in medium (no serum). The final concentration of fetal bovine serum was 1% and the volume was 150 μL when cells were added to the upper chamber. We added 10% FBS medium in the lower chamber to make the volume 500 μL. After 48 h of incubation in the cell incubator, the upper chamber fluid was absorbed and placed in a 24-well plate containing 500 μL of 4% paraformaldehyde (G1101, Servicebio, China). The cells were fixed at room temperature for 20 min. After imbibing the fixative solution, the cells were placed in a 24-well plate containing 500 μL 0.1% crystal violet solution (G1014, Servicebio) for 20 min, and then the inner surface cells of the bottom membrane of the upper ventricle were wiped off. The results were observed and captured under the microscope. For invasion measurement [19 (link)], the apical chamber was coated with Matrigel matrix and then cells were added. The remaining steps were the same as those in migration detection.