Transwell migration and invasion assays

The migration and invasion ability of the ovarian cancer cells was detected using a 24-well Transwell chamber (Costar; Corning, Inc.) with an 8.0-µm pore size. The transfected cells were suspended in serum-free DMEM and inoculated in the upper chamber at a density of 5.0×10⁵ cells/well. Matrigel-coated chambers (BD Biosciences) were used for the invasion assay, while chambers without Matrigel coating were used for the migration assay. The chamber coating was performed at 37°C for 30 min. Medium containing 10% FBS was added to the lower chamber with or without rhCTGF. After 48 h of incubation at 37°C, the migratory or invading cells on the membrane were fixed with methanol and stained with 0.1% crystal violet (Beyotime Institute of Biotechnology) at ambient temperature for 20 min. The number of migrating and invading cells was counted in 5 random fields using a Leica AM6000 microscope.