Figure 4

Migration of Db cell lines and Met cell lines in response to serum. Cells were placed in serum-free medium in the upper chamber of transwell units with 8 μm porosity polycarbonate filter membranes. Medium with 10% FBS was used as a chemoattractant in the lower chamber. Cells were incubated for 18–24 hours, and the cells on the upper surface were removed and the cells on the lower surface were fixed and stained. Cells were visualized with a phase contrast microscope and were photographed. (a) A representative field (40 × magnification) showing very few Db cells migrated in response to the serum. (b) A representative field (40 × magnification) of Met cells showing a much higher number of migratory cells. (c) Migration was quantitated by assessing the mean number of cells that had migrated through the membrane in four representative 20 × fields. Met cells demonstrated a migratory capacity 19 times higher than Db cells (P = 0.001).