ASPARAGINE-LINKED OLIGOSACCHARIDES IN MALIGNANT-TUMOR GROWTH

The expression of beta 1-6-branched complex-type oligosaccharides in several tumour cell models appears to be associated with enhanced metastatic potential. P2B, a major PHA-L-binding glycoprotein was isolated from metastatic MDAY-D2 cells and shown to bind to collagen, fibronectin and laminin with increased affinity after removal of N-linked sialic acid or polylactosamine. Sialylated polylactosamine-containing beta 1-6-branched oligosaccharides on proteins such as P2B and fibronectin may reduce cell adhesion and enhance tumour cell invasion. The loss of branched complex-type oligosaccharides in tumour cells due to somatic mutations or inhibition by swainsonine is also associated with decreased cell proliferation in tissue culture and slower rates of solid tumour growth in mice.