ADHESION OF HUMAN BREAST-CARCINOMA TO EXTRACELLULAR-MATRIX PROTEINS IS MODULATED BY GALECTIN-3

In this report, we have analyzed the adhesive interactions of a breast carcinoma cell line, BT-549, and its galectin-3-transfected subclone 11-9-1-4 with laminin, collagen IV and fibronectin. We determined that 11-9-1-4 cells adhered much more rapidly (within 1 h of plating) to l aminin- and collagen IV-coated wells than the galectin-3 null expressi ng BT-549 cells. However, after 24 h, both cell lines fully adhered to laminin and collagen IV. Both cell lines also achieved maximum adhesi on to fibronectin within 30 min. Not only did 11-9-1-4 express galecti n-3 in the usual punctate pattern on its cell surface, it demonstrated a higher surface expression of alpha(6) beta(1) integrin compared to BT-549. The 11-9-1-4 cells were able to invade through matrigel-coated polycarbonate filters at approximately 3 times the rate of BT-549 par ental cells. Our data suggest that galectin-3 is essential for adhesio n to laminin and collagen IV but not fibronectin by breast carcinoma c ells. In addition, galectin-3 expression may modulate the surface expr ession of some of the integrins specific for laminin and collagen IV a dhesion and invasion of basement membrane by breast carcinoma cells.