2.6. Transwell migration and invasion assays

The determination of cell migration and invasion abilities was conducted using a polycarbonate insert featuring 8-μm pores (Corning, NY, USA) in 24-well plates. Initially, 1x10⁵ cells were positioned within each upper chamber, along with 300 μL of medium lacking serum. Subsequently, in the lower compartment, DMEM containing 30 % FBS was added. For the invasion assay, each upper chamber was pre-coated with 50 μL Matrigel (Becton Dickinson, USA) at least 24 h in advance. Following an incubation period of 48 h, the cells were fixed using 4 % paraformaldehyde for 25 min. Subsequently, the fixed cell and were stained with crystal violet (Solarbio, Beijing, China) for 20 min [13]. A minimum of five randomly chosen visual fields per chamber were assessed. The cell count in each field was conducted under a light microscope.