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An epithelial scatter factor released by embryo fibroblasts
Abstract:
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.
Insights
Human embryo fibroblast-conditioned medium contains a protein factor that causes epithelial cells to separate and scatter. This scattering factor affects cell migration and shape, with potential roles in epithelial cell mobilization.
Area of Science:
- Cell Biology
- Biochemistry
Background:
- Epithelial cells form crucial structural barriers.
- Cell-cell junctions maintain tissue integrity.
- Factors influencing epithelial cell behavior are key to understanding tissue dynamics.
Purpose of the Study:
- To investigate the effects of conditioned medium from human embryo fibroblasts on epithelial cell structure and behavior.
- To characterize the nature of the active component responsible for cell scattering.
Main Methods:
- Utilized Madin-Darby Canine Kidney (MDCK) cells for an in vitro scattering assay.
- Assessed activity through serial dilutions of conditioned medium.
- Determined properties of the active factor including heat lability, non-dialyzability, and sensitivity to trypsin.
Main Results:
- Conditioned medium induced separation and scattering of epithelial cells by disrupting structural junctions.
- The scattering activity was potent, effective at high dilutions (1:64) and low protein concentrations (<100 ng).
- Cell separation initiated within 15 minutes and completed within 10 hours, also affecting MDCK cell migration and dome formation.
Conclusions:
- A heat-labile, trypsin-sensitive protein factor in human embryo fibroblast-conditioned medium disrupts epithelial cell junctions.
- This factor promotes cell scattering and migration, suggesting a role in epithelial cell mobilization.
- Further purification and identification of the factor are needed to elucidate its precise physiological function.