Retinoic acid modulation of alpha(1-->2) fucosyltransferase activity and sensitivity of tumor cells to LAK-mediated cytotoxicity.

We examined the effects of all-trans retinoic acid (RA) on alpha(1-->2) fucosyltransferase activity and sensitivity to LAK-mediated cytotoxicity in two rat colon carcinoma cell lines differing by their glycosylation state and their tumorigenic potential. RA induced a decrease in alpha(1-->2) fucosyltransferase activity in the more tumorigenic variant PROb. Fucosyltransferase mRNA levels were not affected by RA treatment in PROb cells, suggesting a posttranscriptional control. This inhibition was accompanied by a decreased expression of fucosylated membrane glycoconjugates and by a significant increase in the sensitivity to LAK-mediated cytotoxicity. REGb cells, which exhibited a very low enzymatic activity and very few fucosylated glycoconjugates, were more sensitive to LAK-lysis than PROb cells and were not affected by RA treatment.