Expression of E-, P-, n-cadherins and catenins in human bladder carcinoma cell lines.
OBJECTIVE
Cadherins are cell surface glycoproteins that mediate Ca2+-dependent, homophilic cell-cell adhesion. The classical cadherins, E-, P- and N-cadherins, are known to self-associate from their extracellular domain, while their cytoplasmic domain interacts with either beta-catenin or plakoglobin (gamma-catenin), which in turn is bound to alpha-catenin that links the complex to the actin cytoskeleton. The aim of the present study was to analyze the expression of E-, P- and N-cadherins and catenins in human bladder carcinoma cells.


METHODS
Five human bladder carcinoma cell lines, representing a variety of differentiation states, were grown in cell culture. We performed a cell aggregation assay, specific for biological cadherin activity. The expression of cadherins and catenins was analyzed by immunocytochemistry, Western blotting and RT-PCR. The interactions between cadherins and catenins were assessed by immunoprecipitation.


RESULTS
We observed a reduced E-cadherin expression in the poorly differentiated and invasive-tumor derived cells. Interestingly, immunofluorescence study reveals the persistent localization of catenins at intercellular contacts in two E-cadherin deficient cell lines (T24 and TCCSUP) which yet exhibit an epithelial-like morphology and a calcium-dependent adhesive capacity. This suggests that other cadherin(s) are expressed in these both cell lines. P-cadherin, another epithelial cadherin, is expressed only in E-cadherin positive cells. On the other hand, N-cadherin is present at cell-cell borders in the very anaplastic cell lines, T24 and TCCSUP, and is able to link beta-catenin or plakoglobin.


CONCLUSIONS
These results indicate that N-cadherin may participate in intercellular adhesion, while facilitating bladder tumorigenesis.
Mialhe
A
A
Laboratory of Cell Migration and Tumoral Invasion, Research Group on Bladder Tumors, Albert Bonniot Institute, Joseph-Fourier University, France.
Levacher
G
G
Champelovier
P
P
Martel
V
V
Serres
M
M
Knudsen
K
K
Seigneurin
D
D
D000199:Actins / Q000235:genetics; D000708:Anaplasia; D015153:Blotting, Western; D015820:Cadherins / Q000235:genetics*; D002277:Carcinoma / Q000235:genetics* / Q000473:pathology; D002448:Cell Adhesion / Q000235:genetics; D015815:Cell Adhesion Molecules / Q000235:genetics*; D003598:Cytoskeletal Proteins / Q000235:genetics*; D051180:Desmoplakins; D003896:Desmosomes / Q000235:genetics; D004848:Epithelium / Q000473:pathology; D005455:Fluorescent Antibody Technique; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D007365:Intercellular Junctions / Q000648:ultrastructure; D016133:Polymerase Chain Reaction; D011233:Precipitin Tests; D015534:Trans-Activators; D014407:Tumor Cells, Cultured; D001749:Urinary Bladder Neoplasms / Q000235:genetics* / Q000473:pathology; D051178:alpha Catenin; D051176:beta Catenin; D051185:gamma Catenin
D000199:Actins; C495273:CTNNA1 protein, human; C495270:CTNNB1 protein, human; D015820:Cadherins; D015815:Cell Adhesion Molecules; D003598:Cytoskeletal Proteins; D051180:Desmoplakins; C495292:JUP protein, human; D015534:Trans-Activators; D051178:alpha Catenin; D051176:beta Catenin; D051185:gamma Catenin