Effect of ECM proteins on cancer cell migration. (A) U87 cells, (B) U251N cells, (C) MDA-MB-231, (D) MCF-7, (E) HeLa cells. Cells (250,000 to 300,000) were seeded in 6-well plates pre-coated with various ECM proteins and cloning rings were used as described in Materials and Methods. After removal of rings, photographs of the gaps were taken at different migration time points, i.e. 0 h, 24 h, (or 36 h), 48 h and 72 h. The gap areas of the ring cell migration assays were measured using Image J software. The areas were plotted against migration time. Values represent the mean ± s.e.m. (some of which are obscured by the symbols). N = 4 to 10 gaps from three rings. Data shown are representative of three independent experiments. The differences at each time point between control and various ECM protein coatings were determined by post-hoc tests for pairwise comparison (after one-way ANOVA analysis) and Bonferroni correction for multiple testing. *p < 0.05; **p < 0.01; ***p < 0.001.