[Expression of laminin is correlated to the differentiation of human colonic cancer cells].
The level and molecular composition of laminin, a major basement membrane glycoprotein formed of three chains (A, B1 and B2) have been analyzed in various human colonic cancer cells (Caco-2 and HT29). The synthesis of laminin over a 24 h period, corresponding to cellular and secreted molecules purified by affinity chromatography, was the highest in the more differentiated cells. Immunocytochemical detection of the constituent chains of laminin in permeabilized cells as well as after separation on polyacrylamide gels showed that A, B1 and B2 chains were expressed in Caco-2 cells, whereas A chain was not detected in HT29 cells. When cancer cells were cultured on a monolayer of confluent fibroblastic cells, laminin was deposited at the basement membrane level only in the case of the most differentiated cells. In an attempt to define the role of laminin-A chain, transfection of Caco-2 cells with A chain antisense cDNA was performed; among the clones obtained, 3 were deficient for the target polypeptide. The consequences of the absence of laminin-A chain on basement membrane formation, cellular differentiation and tumor invasion will be currently determined.
De Arcangelis
A
A
Unité INSERM 381, Strasbourg.
Simo
P
P
Lesuffleur
T
T
Kedinger
M
M
Simon-Assmann
P
P
D001485:Basement Membrane / Q000378:metabolism; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007158:Immunologic Techniques; D066298:In Vitro Techniques; D007797:Laminin / Q000032:analysis / Q000378:metabolism*; D014162:Transfection; D014407:Tumor Cells, Cultured / Q000378:metabolism
D007797:Laminin
L'expression de la laminine est corrélée à la différenciation des cellules cancéreuses coliques humaines.