The c-Ha-ras oncogene induces increased expression of β-galactoside α-2,6-sialyltransferase in rat fibroblast (FR3T3) cells

• Published in: Glycobiology (Oxford) 1992-02, Vol.2 (1), p.49-56
• Main Authors: Le Marer, Nadia, Laudet, Vincent, Svensson, Eric C., Cazlaris, Haris, Van Hille, Benoit, Lagrou, Christian, Stehelin, Dominique, Montreuil, Jean, Verbert, André, Delannoy, Philippe
• Format: Article
• Language: English
• Subjects: 6-sialyltransferase; Animals; c-Ha-ras; Carbohydrate Sequence; Cell Line, Transformed; Cell Membrane - metabolism; Cell Transformation, Neoplastic - genetics; Fibroblasts - metabolism; Fluorescent Antibody Technique; Galactosides - genetics; Gene Expression; Genes, ras - physiology; Glycoconjugates - metabolism; Immunosorbent Techniques; Molecular Sequence Data; N-Acetylneuraminic Acid; Oncogenes; Rats; RNA, Messenger - biosynthesis; sialic acids; Sialic Acids - metabolism; Sialyltransferases - genetics; Transfection; transformation; α-2
• ISSN: 0959-6658; 1460-2423
• DOI: 10.1093/glycob/2.1.49

Alteration in cell surface carbohydrates, and in particular cell surface sialylation, have been known to occur during oncogenic transformation. To examine the basis for such changes, we have transformed the rat fibroblast cell line FR3T3 with the oncogenes c-Ha-ras EJ, v-mycOK10, v-src, polyoma virus middle T or the transforming bovine papilloma virus 1 (BPV1), and measured the sialyltransferase activities of cellular lysates. We found that, in contrast to all other oncogenes examined, c-Ha-ras induced a striking increase in β-galactoside α-2,6-sialyltransferase (Gal α-2,6-ST) activity in FR3T3 cells. This increase in Gal α-2,6-ST activity resulted in the increased expression of cell surface α-2,6-linked sialic acid on cell surface glyco-conjugates, as determined by cell staining with fluoresceinlabelled Sambucus nigra agglutinin. Immunoprecipitation and immunofluorescence experiments revealed that the increase in Gal α-2,6-ST activity was due to an elevation of expression of the enzyme. Moreover, Northern analysis suggested that the increased expression of this enzyme was the result of an increase in the steady-state mRNA level of the Gal α-2,6-ST gene. These results support the notion that alterations seen in cell surface glycoconjugates during oncogenic transformation can be the result of altered expression of glycosyltransferases.