Cell invasion assay

Matrigel (BD, Franklin Lakes, NJ) was thawed overnight at 4 ng and diluted (1-5 mg/mL) in serum-free cold DMEM. A 100 μL volume of the diluted Matrigel was added to the upper chamber of a Transwell apparatus and incubated at 37°C for 4-5 hrs to allow the gel to swell. The treated U87MG, U251MG and LN229 cells (2 × 10⁵ cells/mL) were prepared in serum-free medium, and 200 μL of prepared cell suspension was added to each insert. Medium containing FBS (750 μL) was added to the lower chamber of the Transwell apparatus. After 24 hrs, non-invading cells were removed, and the invading cells were quantified as described above [29].