Transwell Boyden Chamber Invasion Assay

The invasion ability of MCF-7 cells was tested in a Transwell Boyden Chamber (6.5-mm, Costar) as described previously (Wang et al., 2017 (link)). The polycarbonate membranes (8-μm pore size) on the bottom of the upper compartment of the Transwells were coated with 1% human fibronectin (R&D Systems 1918-FN, USA). The cells were harvested 12 h after transfection and suspended in FBS-free DMEM culture medium. Then, cells were added to the upper chamber (2 × 10⁴ cells/well). At the same time, 0.5 mL of DMEM containing 10% FBS was added to the lower compartment, and the Transwell-containing plates were incubated for 6 h in a 5% CO₂ atmosphere saturated with H₂O.