ROCK-Generated Contractility Regulates Breast Epithelial Cell Differentiation in Response to the Physical Properties of a Three-Dimensional Collagen Matrix

• Published in: The Journal of cell biology 2003-11, Vol.163 (3), p.583-595
• Main Authors: Wozniak, Michele A., Desai, Radhika, Solski, Patricia A., Der, Channing J., Keely, Patricia J.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence - genetics; Breasts; Cell Adhesion - drug effects; Cell Adhesion - physiology; Cell Differentiation - drug effects; Cell Differentiation - physiology; Cell division; Cell Division - drug effects; Cell Division - physiology; Cell growth; Cell Line; Cell Movement - drug effects; Cell Movement - physiology; Cell Size - drug effects; Cell Size - physiology; Cells; Cellular biology; Collagen - pharmacology; Collagens; Cultured cells; Down-Regulation - drug effects; Down-Regulation - physiology; Epithelial cells; Epithelial Cells - cytology; Epithelial Cells - drug effects; Epithelial Cells - physiology; Extracellular Matrix - metabolism; Female; Focal Adhesion Kinase 1; Focal Adhesion Protein-Tyrosine Kinases; Focal adhesions; Focal Adhesions - drug effects; Focal Adhesions - metabolism; Gels; Gels - pharmacology; Humans; Intracellular Signaling Peptides and Proteins; Mammary Glands, Human - cytology; Mammary Glands, Human - growth & development; Phosphorylation; Phosphorylation - drug effects; Physiological regulation; Protein-Serine-Threonine Kinases - genetics; Protein-Serine-Threonine Kinases - metabolism; Protein-Tyrosine Kinases - metabolism; rho GTP-Binding Proteins - metabolism; rho-Associated Kinases
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.200305010

Breast epithelial cells differentiate into tubules when cultured in floating three-dimensional (3D) collagen gels, but not when the cells are cultured in the same collagen matrix that is attached to the culture dish. These observations suggest that the biophysical properties of collagenous matrices regulate epithelial differentiation, but the mechanism by which this occurs is unknown. Tubulogenesis required the contraction of floating collagen gels through Rho and ROCK-mediated contractility. ROCK-mediated contractility diminished Rho activity in a floating 3D collagen gel, and corresponded to a loss of FAK phosphorylated at Y397 localized to 3D matrix adhesions. Increasing the density of floating 3D collagen gels also disrupted tubulogenesis, promoted FAK phosphorylation, and sustained high Rho activity. These data demonstrate the novel finding that breast epithelial cells sense the rigidity or density of their environment via ROCK-mediated contractility and a subsequent down-regulation of Rho and FAK function, which is necessary for breast epithelial tubulogenesis to occur.