Transwell migration assay
In 24 well plates with transwell chamber inserts (Costar 3464, Corning), U2OS WT and MMP-2 KO cells were seeded, separately, in the upper chamber at 20,000 cells in 200 µl serum-free DMEM. In the bottom chamber of the well 800 µl DMEM supplemented with 10% FBS was added. The plates containing triplicates of WT and KO were cultured for 24 hours under standard culture conditions. The following day, non-migrating cells were removed from the upper chamber and migrating cells were fixed with 70% ethanol and stained with 0.2% crystal violet. Membranes were left to dry and images were taken.