An epithelial scatter factor released by embryo fibroblasts.

Medium conditioned by human embryo fibroblasts breaks structural junctions between several types of epithelial cells, leading to separation and scattering of the cells. An assay developed in MDCK cells shows activity up to a dilution of at least 1 in 64, equivalent to less than 100 ng of total protein. The activity is non-dialysable, heat-labile, and sensitive to trypsin, and it is assumed to be due to one or more proteins. After addition of the factor, separation of MDCK cells begins in about 15 min and is complete in 10 h. It increases migration of MDCK cells into wounds, and causes collapse of domes. Locomotion of isolated cells is not enhanced, but cell shape is affected by local membrane movement. Under the culture conditions used the factor, or an associated protein, causes a weak inhibition of cell growth without cytotoxic activity. The scattering factor has not been purified, nor has a physiological role been identified, but it might be concerned in the mobilization of epithelial cells.