Fig. 6.

Parental and Ecad-myc 4T1 cell spheroids display extensive invasion of single cells and multicellular structures in 3D collagen. Spheroids of parental (A) and Ecad-myc (B) 4T1 cells were prepared as described in the Materials and Methods. After embedding in 3D collagen, micrographs of full spheroids were taken at 18 h and 7 days. Dashed red boxes in the left panels indicate the regions magnified in the adjacent panels. Arrows point to examples of single cells that have detached from the spheroids during invasion. Images are representative of two independent experiments. Scale bars: 250 μm.