High alpha-2,6-sialylation of N-acetyllactosamine sequences in ras-transformed rat fibroblasts correlates with high invasive potential

Abstract

Through cloning experiments with the FRras EJ4 cell line, previously described to exhibit a Sambucus nigra agglutinin (SNA)+ phenotype, three clones with a SNA− phenotype were isolated. All the selected SNA+ and SNA− clones expressed the ras oncoprotein and cloned in soft agar with the same efficiency. We were interested in studying the adhesion and Invasion properties of the FRras cells presenting a SNA + or − phenotype. They were first compared in their biochemical properties and we found that FRras SNA− were characterized by a low α-2,6-sialylation of their cell surface glycoproteins and a low β-galactoside α-2,6 sialyltransferase activity. Using in vitro invasion assays, FRras cells exhibiting a low α-2,6-sialylation on their surface were found to have a low invasive potential compared to their counterpart SNA+. FRras SNA− clones exhibit a different morphology from that of FRras SNA+ clones. Moreover, homotypic aggregation assays indicated that FRras SNA− were more cohesive with each other and adhesion assays showed that they were more adhesive to fibronectin.