Figure 5.

Influence of fibroblast derived SPARC on cancer cell migration. F331 fibroblasts transfected with either scr control, SPARC siRNA (KD) or KD cells with additional rSPARC were seeded at high numbers and allowed to secrete and modulate their respective ECM. After 5 days, cancer cells were added on top of the fibroblast monolayers and migration of individual cells was recorded for a total of 22 h. (A–C) shows the resulting tracks for HCT116 cells migrating on F331 with KD, KD + rSPARC and scr control. Similar tracks for SW480 cells are summarized in (D–F). Red circles indicate track length based on maximum Euclidian distance and were positioned at 50%, 100% and 150% of the longest track of the KD group. The average migration speed in µm/min of HCT116 (G) and SW480 (H) was plotted as mean values for each well (n = 10) of 2 independent experiments using 2 different siRNAs. Statistical analysis for different migration velocities was performed by using the Kruskal-Wallis test followed by Dunn’s multiple comparisons test. *: p < 0.05; ****: p < 0.0001. Scatter dot plots: center line, means; whiskers, SD; KD, knockdown; rSPARC, human recombinant SPARC; scr, scrambled control.