In vitro migration assay was performed as we described in the study by Nellius et al.16 (link) with few minor modifications. 1.5 × 106 cells/ml were seeded on top of the gelatinized microporous membrane (8-mm pore size Corning insert). After 2 h, serum-free media was added to the bottom part of the well and incubated at 37 °C overnight. Migrated cells were visualized using the Diff-Quick staining kit (Dade Behring, Deerfield, IL, USA) and counted in 10 high-powered fields ( × 60).