Cell migration and invasion assays were performed in triplicates using Transwells in 24-well plates. Transwells with 8-μm pore polycarbonate membrane used for cell migration assay were obtained from Corning (Corning, NY). Transwells coated with Matrigel on the upper surface used for invasion assay were obtained from BD Biosciences (Franklin Lakes, NJ). Cells (2 × 104 for migration assay; 5 × 104 for invasion assay) suspended in 250 μl of serum-free medium were placed in the upper chamber, while the lower chamber was loaded with 750 μl of cell culture medium with 10% FBS. After 24 h of incubation, the non-invaded cells were removed from the upper surface by a cotton swab. The invaded cells on the lower surface of the membrane were fixed in 100% methanol for 15 min, air-dried, and stained with 0.1% crystal violet. Cells from three microscopic fields were photographed and counted.