Figure 6

Proliferation effects decrease in relation with distance from endothelial cells. A) Schematic representation of BRENCs and epithelial cells in gradient co-culture. BRENCs and epithelial cells were embedded into separate gels on culture plates. The gels were allowed to fuse before culture medium was added. B) Composite image of the gradient co-culture demonstrating the epithelial and endothelial boundaries. Phase contrast image demonstrates the spatial distribution of epithelial colonies. The size of the colonies decreases proportionally with the distance from BRENCs. The distal colony growth, however, demonstrates that the endothelial effects are mediated at least partially by soluble factors. C) Effects of endothelial cells are most prominent at close distance to epithelial cells. Gradient co-culture show prominent proximal effects in MCF10A. The effects are however still present distally. No distal effects were seen in co-culture of BRENCs and MB-MDA-231. The apparent difference between co-culture and proximal windows can possibly be explained by the earlier appearance of mesenchymal colonies in co-culture.