Fig. 6. Two-dimensional cell migration analysis. (A) Average velocity of MDA MB231cells on FN or FN-fibulin-1 substrata. Each value that is plotted represents an average velocity calculated from the displacement of 20 cell centroids during a 5 hour period. Shown are data from two and three independent experiments of cell migration on FN and FN-fibulin-1 substrata, respectively. Lines represent linear fits of all points in all experiments for each substratum. (B) Average distance that a cell travelled during a given time on FN versus FN-fibulin-1 substratum. Each plotted value represents an average of the distance travelled for 20 cells for various times beginning 1 hour after seeding onto FN or FN-fibulin-1. Shown are data from two and three independent experiments of cell migration on FN and FN-fibulin-1 substrata, respectively. (C) Average distance that MDA MB231 cells transfected with either empty vector or fibulin-1 expression construct travel as a function of time on FN substratum. Each plotted value represents an average of the distance travelled by 20 cells for various times after seeding onto FN. (D) Quantification by ELISA of the amount of fibulin-1 secreted into the medium by MDA MB231 cells transfected with fibulin-1 expression construct.