Cluster speeds show temporal differences in the different regions of the circle (A), square (B) and cross (C) shapes respectively.

<p>Speeds from the sides increase (I), plateau (II) and finally decrease (III) over time. These results show clear differences in cluster edge speeds which depend on spatial location in the geometry. Significant differences (p<0.05) in speeds are indicated in each figure.</p

Velocity and vorticity fields in MCF7 cell monolayers in the circle (A), square (B), cross vertex (C) and intersections (D) at 30 hours summed every hour.

<p>The solid black line is the cluster border at the start of migration. Scale bar = 250 μm.</p

MCF7 cells at the time of release from circle (A), square (B) and cross (C) shaped constraints are shown.

<p>A representation of the regions chosen as the vertices (red), sides (blue) and intersections (green) in the three shapes are indicated in the boxes. Scale bar = 500 μm.</p

Velocity and vorticity plots are shown for cell clusters treated with 50 μM blebbistatin to inhibit myosin2 and alter cytoskeletal tension.

<p>A. MCF7 at 30 hours and B. MDCK at 16 hours. Scale bar = 200 μm.</p

Fluorescence images show actin (red) and the nucleus (blue) for MCF7 clusters at 0 hours (A), 24 hours (B), and 48 hours (C) after release from constraints.

<p>There is no clear cable-like structure bounding the cluster. Scale bar = 100 μm.</p

Velocity fields and vorticity maps for MDCK cells are shown at 2 hours (A, D), 8 hours (B, E) and 16 hours (C, F) after removal of constraint.

<p>The cluster border is also shown at 0 hours for reference. Cells in the vertices show minimal movement as compared to those in the sides and intersections (D, E, F). We see the development of vortices, in both clockwise (blue) and counter clockwise (yellow-red) directions at intersections by 16 hours. Scale bar = 250 μm.</p

Migrations of MCF7 cells located on the advancing edges of the circle (A), square (B) and cross shapes (C) were obtained using individual cell tracking and are illustrated on a windrose plot to show the cell migration trajectories from the cluster edge.

<p>We see differences in motility that depend on the cell spatial positions which are labelled corresponding to sides, vertices and intersections.</p

Gelatin Methacrylate Hydrogels as Biomimetic Three-Dimensional Matrixes for Modeling Breast Cancer Invasion and Chemoresponse in Vitro

Recent studies have shown that three-dimensional (3D) culture environments allow the study of cellular responses in a setting that more closely resembles the in vivo milieu. In this context, hydrogels have become popular scaffold options for the 3D cell culture. Because the mechanical and biochemical properties of culture matrixes influence crucial cell behavior, selecting a suitable matrix for replicating in vivo cellular phenotype in vitro is essential for understanding disease progression. Gelatin methacrylate (GelMA) hydrogels have been the focus of much attention because of their inherent bioactivity, favorable hydration and diffusion properties, and ease-of-tailoring of their physicochemical characteristics. Therefore, in this study we examined the efficacy of GelMA hydrogels as a suitable platform to model specific attributes of breast cancer. We observed increased invasiveness in vitro and increased tumorigenic ability in vivo in breast cancer cells cultured on GelMA hydrogels. Further, cells cultured on GelMA matrixes were more resistant to paclitaxel treatment, as shown by the results of cell-cycle analysis and gene expression. This study, therefore, validates GelMA hydrogels as inexpensive, cell-responsive 3D platforms for modeling key characteristics associated with breast cancer metastasis, in vitro