Increase in cell surface wheat germ agglutinin binding in a rat hepatoma cell line dRLa 74 treated with concanavalin A.

Wheat germ agglutinin binding to a rat hepatoma cell line dRLa 74 treated with concanavalin A was studied. It increased depending on the concanavalin A concentration in the culture medium. The cells exhibited about twofold increase in wheat germ agglutinin-binding when pretreated with 50 micrograms/ml of concanavalin A for 48 h. The wheat germ agglutinin binding sites were shown to be localized at the cell surface by lectin-histochemistry. Wheat germ agglutinin blotting of microsomal membrane proteins showed a broad wheat germ agglutinin-reactive band with an apparent molecular weight of 90 to 100 kDa. Loss of wheat germ agglutinin binding to dRLa 74 cells and the glycoprotein after neuraminidase treatment suggested that wheat germ agglutinin reacted with cell surface sialyl residues of dRLa 74 cells. The induced change was reversible. Increased wheat germ agglutinin binding returned to the pretreatment level when the concanavalin A-treated cells were subcultured in the absence of concanavalin A. These observations suggest that environmental factors interacting with tumor cell surface sugar moieties may induce reversible epigenetic changes on cell surface carbohydrate structures.