Study on the Mechanism of Fibronectin Adhesion to NIH3T3 cell Stimulated by Retinoic Acid.

Retinoic acid (RA) is an inducer of cell differentiation. Recently, it was discovered that RA widely works on cells, causing a series of physiological alterations, and may make the tumor cell differentiation back to the normal cells, but little is known about its role in the adhesion of the cell to the extracellular matrix (Fn). We observed that RA increased the ability of NIH3T3 cells to adhere to Fn in a dose-dependent manner. The cell adhesion to fibronectin was promoted by 20% with 32 &mgr;mol/L RA, but not to polylysine. We use anti-integrin alpha(5)-subunit and beta(1)-subunit monoclonal antibodies to measure the amounts of integrin on the cell surface by FCM. It showed that the amounts of alpha(5) and beta(1) subunits of integrin did not change when the NIH3T3 cells were treated with RA for 24 h. But the incorporation of (3)H-mannose was increased by 53 % and those of tri- or tetra- antennary or bisecting complex type oligosaccharides were increased by 13 %. These results indicated that the increased adhesion of the cells to Fn in presence of RA may be caused by altering amounts and types of the oligosaccharides of the glycoprotein on the cell surface.