Abstract
We have previously shown that an integral plasma membrane glycoprotein (AP2) is highly polarized to the apical domain in confluent Madin-Darby canine kidney (MDCK) epithelial cells. However, when the monolayers are prevented from forming intercellular contacts, approximately 60% of the AP2 cellular content is stored in the intracellular vacuolar apical compartment (VAC). In the current work we found that AP2 was present in the non-tumorigenic human mammary epithelial cell line MCF-10A, in the breast carcinoma cell lines MCF-7 and T47D, and in breast ductal carcinomas in vivo. By radioimmunoassay, an intracellular compartment of AP2 was identified in the mammary cell lines in culture. In MCF-10A, this compartment behaved as in MDCK cells; namely it was observed only when the cells cannot form cell-cell contacts. However, in the carcinoma cell lines MCF-7 and T47D, a significant AP2 intracellular compartment was observed also under conditions permissive for the formation of intercellular contacts. These results were confirmed by immunofluorescence and immunoelectron microscopy experiments that showed VACs in MCF-7 and T47D, even in cells with extensive intercellular contacts. In MCF-7 cells, the addition of serum caused a partial decrease of the AP2 intracellular compartment. The exocytosis of VACs occurred towards the center of multi-cellular groups, forming intercellular lumens, similar to those transiently observed in MDCK cells and to structures described by others during embryo development. Altogether, these results suggest that VAC exocytosis is controlled by cell-cell contact signalling, which may be defective in carcinoma cells.
| Original language | English |
|---|---|
| Pages (from-to) | 131-141 |
| Number of pages | 11 |
| Journal | Differentiation |
| Volume | 54 |
| Issue number | 2 |
| DOIs | |
| State | Published - Dec 31 1993 |
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ASJC Scopus subject areas
- Pathology and Forensic Medicine
- Developmental Biology
- Cell Biology
Cite this
Vacuolar apical compartment (VAC) in breast carcinoma cell lines (MCF-7 and T47D) : Failure of the cell-cell regulated exocytosis mechanism of apical membrane. / Vega-Salas, D. E.; San Martino, J. A.; Salas, Pedro J; Baldi, A.
In: Differentiation, Vol. 54, No. 2, 31.12.1993, p. 131-141.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Vacuolar apical compartment (VAC) in breast carcinoma cell lines (MCF-7 and T47D)
T2 - Failure of the cell-cell regulated exocytosis mechanism of apical membrane
AU - Vega-Salas, D. E.
AU - San Martino, J. A.
AU - Salas, Pedro J
AU - Baldi, A.
PY - 1993/12/31
Y1 - 1993/12/31
N2 - We have previously shown that an integral plasma membrane glycoprotein (AP2) is highly polarized to the apical domain in confluent Madin-Darby canine kidney (MDCK) epithelial cells. However, when the monolayers are prevented from forming intercellular contacts, approximately 60% of the AP2 cellular content is stored in the intracellular vacuolar apical compartment (VAC). In the current work we found that AP2 was present in the non-tumorigenic human mammary epithelial cell line MCF-10A, in the breast carcinoma cell lines MCF-7 and T47D, and in breast ductal carcinomas in vivo. By radioimmunoassay, an intracellular compartment of AP2 was identified in the mammary cell lines in culture. In MCF-10A, this compartment behaved as in MDCK cells; namely it was observed only when the cells cannot form cell-cell contacts. However, in the carcinoma cell lines MCF-7 and T47D, a significant AP2 intracellular compartment was observed also under conditions permissive for the formation of intercellular contacts. These results were confirmed by immunofluorescence and immunoelectron microscopy experiments that showed VACs in MCF-7 and T47D, even in cells with extensive intercellular contacts. In MCF-7 cells, the addition of serum caused a partial decrease of the AP2 intracellular compartment. The exocytosis of VACs occurred towards the center of multi-cellular groups, forming intercellular lumens, similar to those transiently observed in MDCK cells and to structures described by others during embryo development. Altogether, these results suggest that VAC exocytosis is controlled by cell-cell contact signalling, which may be defective in carcinoma cells.
AB - We have previously shown that an integral plasma membrane glycoprotein (AP2) is highly polarized to the apical domain in confluent Madin-Darby canine kidney (MDCK) epithelial cells. However, when the monolayers are prevented from forming intercellular contacts, approximately 60% of the AP2 cellular content is stored in the intracellular vacuolar apical compartment (VAC). In the current work we found that AP2 was present in the non-tumorigenic human mammary epithelial cell line MCF-10A, in the breast carcinoma cell lines MCF-7 and T47D, and in breast ductal carcinomas in vivo. By radioimmunoassay, an intracellular compartment of AP2 was identified in the mammary cell lines in culture. In MCF-10A, this compartment behaved as in MDCK cells; namely it was observed only when the cells cannot form cell-cell contacts. However, in the carcinoma cell lines MCF-7 and T47D, a significant AP2 intracellular compartment was observed also under conditions permissive for the formation of intercellular contacts. These results were confirmed by immunofluorescence and immunoelectron microscopy experiments that showed VACs in MCF-7 and T47D, even in cells with extensive intercellular contacts. In MCF-7 cells, the addition of serum caused a partial decrease of the AP2 intracellular compartment. The exocytosis of VACs occurred towards the center of multi-cellular groups, forming intercellular lumens, similar to those transiently observed in MDCK cells and to structures described by others during embryo development. Altogether, these results suggest that VAC exocytosis is controlled by cell-cell contact signalling, which may be defective in carcinoma cells.
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UR - http://www.scopus.com/inward/citedby.url?scp=0027380783&partnerID=8YFLogxK
U2 - 10.1111/j.1432-0436.1993.tb00716.x
DO - 10.1111/j.1432-0436.1993.tb00716.x
M3 - Article
C2 - 8243890
AN - SCOPUS:0027380783
VL - 54
SP - 131
EP - 141
JO - Differentiation
JF - Differentiation
SN - 0301-4681
IS - 2
ER -