Cell migration and invasion assay

Cell migration and invasion abilities were analyzed by Transwell chamber assays. A total of 200 µl cell medium (1x10⁵ cells/100 µl in RPMI 1640 medium) were added to the upper chamber of Transwell equipment, and medium containing 10% FBS (HyClone; GE Healthcare Life Sciences) was added to the lower chamber. For invasion assays, Matrigel-coated Transwell cell culture chambers (1:5; BD Biosciences) were introduced. After 24 h, SiHa and CaSki cells on the upper side of the filter were removed with a cotton swab. Migrated and invaded cells on the lower membrane surface were fixed in 4% paraformaldehyde for 30 min at room temperature, stained with 0.1% crystal violet for 15 min at 25˚C and visualized using a light microscope (Olympus Corp.; magnification, x20).