title: E-cadherin negatively regulates CD44-hyaluronan interaction and CD44-mediated tumor invasion and branching morphogenesis.
abstract: CD44 is a principal cell-surface receptor for hyaluronan (HA). Up-regulation of CD44 is often associated with morphogenesis and tumor invasion. On the contrary, reduction of cell-cell adhesion due to down-regulation of E-cadherin is associated with the invasive and metastatic phenotype of carcinomas. In our current study, we investigated the functional relationship between CD44 and E-cadherin. We established an inverse correlation between CD44 and E-cadherin indicating that the cells expressing higher levels of E-cadherin display weaker binding affinity between CD44 and HA. By using TA3 murine mammary carcinoma (TA3) cells, which display CD44-dependent HA binding, branching morphogenesis, and invasion, we demonstrated an inverse functional relationship between CD44 and E-cadherin by transfecting exogenous E-cadherin into the cells. Our results showed that increased expression of E-cadherin in TA3 cells, but not ICAM-1, weakens the binding between CD44 and HA and blocks spreading of the cells on HA substratum and CD44-mediated branching morphogenesis and tumor cell invasion. The results reported here demonstrated for the first time that E-cadherin negatively regulated CD44-HA interaction and CD44 function and suggested that balanced function of CD44 and E-cadherin may be essential for normal epithelial cell functions, and imbalanced up-regulation of CD44 function and/or down-regulation of E-cadherin function likely contributes to tumor progression.
authors.affiliation: Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia 19104, USA.
authors.forename: Yin
authors.initials: Y
authors.lastname: Xu
authors.forename: Qin
authors.initials: Q
authors.lastname: Yu
mesh_terms: D015820:Cadherins / Q000502:physiology*; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism*; D006820:Hyaluronic Acid / Q000378:metabolism*; D009024:Morphogenesis; D009361:Neoplasm Invasiveness; D011485:Protein Binding; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D015820:Cadherins; D018960:Hyaluronan Receptors; D006820:Hyaluronic Acid