Molecular identification of lectin binding sites differentiating related low and high metastatic murine lymphomas

We have previously shown that differences in cell surface carbohydrates can be detected in related murine tumor lines of varying metastatic capacity using plant lectins such as soybean agglutinin (SBA) or Vicia villosa (VV) but not concanavalin A (ConA). Here we show that weakly metastatic Eb cells bind SBA via four glycoproteins and one GL2-like glycolipid. The major high-affinity SBA binding component of weakly metastatic ESb-MP cells was a glycoprotein of 210-220 kd. Highly metastatic ESb cells also expressed this protein but the oligosaccharide side chains were altered in such a way that SBA-binding was completely lost while ConA and peanut agglutinin (PNA) binding remained similar. Quantitative binding studies using iodinated lectins indicated that SBA binding of ESb cells could only be detected at lectin concentrations greater than 75 micrograms/ml. The role of altered carbohydrates in metastasis is discussed.