2.5. Transwell migration and invasion assay

The 24-well transwell chambers with a pore size of 8 µm polycarbonate membrane (Multiskan MK3, Thermo, Waltham, MA, USA) were used to analyze the migration and invasion capacities of colon cells. Cells were seeded into the upper chamber with a serum-free medium without Matrigel coating at a density of 1 × 10⁵ cells per well for the migration assay. For the invasion assay, the upper chamber was coated with Matrigel (BD Biosciences, Franklin Lakes, NJ, USA). Culture medium with 10% FBS was placed in the lower chamber as a chemoattractant. The chambers were incubated at 37°C for 48 h, then the migrated and invasive cells were stained with 0.05% crystal violet for 30 min and counted by the microscope.