For the scratch test, cells were plated at 2×105 cells per well in a 6-well plate and grown overnight under standard conditions. After 12 h, the confluent monolayer was scratched manually with a plastic 200 μl pipette tip and after washing with PBS. Then the culture was continued in 2% serum at 37°C for 24 h. Cells that had migrated into the wound area were imaged using an inverted microscope at 100× magnification (Olympus, CKX41). The distance was measured using ImageJ2x.