Alterations in the glycolipid composition and cellular properties of ovarian carcinoma-derived RMG-1 cells on transfection of the α1,2-fucosyltransferase gene

Transfection of the mouse Fut1 and Fut2, and human FUT1 genes into human ovarian carcinoma-derived RMG-1 cells resulted in 20-30-fold increases in cellular α1,2-fucosyltransferase activity, and in alteration of the glycolipid composition, including not only fucosylated products, but also precursor glycolipids. Although globo-series glycolipids were not significantly affected by the transfection, the major glycolipids belonging to the lacto-series type 1 chain family in RMG-1 cells and the transfectants were the Lc₄Cer, Lewis a (Le)^a and Le^b, and H-1 glycolipids, respectively, suggesting that fucosylation of Lc₄Cer to the H-1 glycolipid prevents the further modification of Lc₄Cer to Le^a and Le^b in the transfectants. Also, the lacto-series type 2 chains in RMG-1 cells were Le^X, NeuAc-nLC₄Cer and NeuAc-Le^X, and those in the transfectants were Le^X and Le^Y, indicating that the sialylation of nLc₄Cer and Le^X is restricted by increased fucosylation of Le^X. As a result, the amount of sialic acid released by sialidase from the transfectants decreased to 70% of that from RMG-1 cells, and several membrane-mediated phenomena, such as the cell-to-cell interaction between cancer cells and mesothelial cells, and the cell viability in the presence of an anticancer drug, 5-fluorouracil, for the transfectants was found to be increased in comparison to that for RMG-1 cells. These findings indicate that cell surface carbohydrates are involved in the biological properties, including cell-to-cell adhesion and drug resistance, of cancer cells.