Figure 3.

Analysis of contractile function and cell-mediated forces. (A) Canine mammary tumor (CMT)-U27 and CMT-U309 cells were cultured on shape-determined, fibronectin (FN)-coated micropatterns (CYTOOchips™), and visualized for the organization of actin cytoskeleton. CMT-U309 cells displayed again only thick straight bundles, while CMT-U27 cells had thinner structures with more variability in their organization pattern. Phalloidin-green, DAPI-blue. Scale bar 10 μm. (B) Contractile function of the actin-based structures was analyzed from the cells cultured on these micropatterns. Contractility is directly correlated with the radius of curvature and is calculated by using the formula: $R=\frac{{\left(L/2\right)}^2+w^2}{w}$, where L = length and w = width. (C) Mean contractile function of CMT-U27 and CMT-U309 cells ± SD, n = 32 (U27), n = 39 (U309). (D) Representative examples of traction force maps of CMT-U27 and CMT-U309 cells. Unit of stress is in pascals (Pa). (E) Root mean square tractions of CMT-U27 and CMT-U309 cells are shown in the upper graph and contractile moment in the lower graph. Means ± SD are shown (n = 7 for U27; n = 10 for U309).