ISSN:
1573-7276
Keywords:
breast carcinoma cell
;
collagen
;
integrin
;
laminin
;
metastasis
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
We examined the expression and ligand specificity of the α2β1 integrin on human mammary epithelial cells (HMEC) and a panel of breast carcinoma cell lines in vitro. We found that the α2β1 integrin was universally, but quite variably expressed on these cells by FACS analysis. No significant correlation was observed between its expression and other known cellular phenotypes. Substrate attachment assays using blocking antibodies demonstrated that α2β1 integrin served as a receptor for collagen on HMEC and almost all breast carcinoma cells. However, its contribution to laminin binding of these cells appeared to be related to cellular differentiation as evaluated by sex steroid receptor status and by markers of epithelial-mesenchymal transition, i.e. loss of E-cadherin and expression of vimentin. Two different populations of non-malignant immortalized HMEC (184A1N4 and MCF-10A) contained cells capable of using α2β1 integrin as a laminin receptor. Breast cancer cell lines positive for estrogen receptor (ER) and E-cadherin (MCF-7, T47D, ZR75-1) could also use α2β1 integrin as a laminin receptor. Conversely, α2β1 integrin appeared to be incapable of binding to laminin or to be a very minor receptor for laminin on metastatic ER-negative breast carcinoma cells that expressed vimentin (MDA-MB 231, MDA-MB 435, and MDA-MB 436). These findings suggest that the ligand specificity of α2β1 integrin, i.e. its function as a laminin receptor, may be regulated during the malignant progression of breast carcinoma cells. A reduced contribution of α2β1 integrin to the cellular laminin binding appears to be associated with an increased malignant phenotype and with an epithelial-mesenchymal transition of breast carcinoma cells.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00133478
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