Histochemical aspects of the process of experimentally induced
metastasis were examined by light and electron microscopy with labelled
lectins employed as a probe. Mouse colon
carcinoma cells (colon 26) were injected into the spleen of Balb/c mice and liver
metastasis was induced. Among the
lectins tested, Erythrina cristagalli
agglutinin (ECA) stained the metastasized colon 26 cells strongly compared with the heterogeneous and faint staining in non-metastasized tumour foci in the spleen or in the subcutaneous space. Other
lectins, such as
Phaseolus vulgaris leucoagglutinin (
PHA-L), Phaseolus vulgaris erythroagglutinin (
PHA-E) and Datura stramonium
agglutinin (DSA), having specificity for branched complex type
sugar chains, did not show any differences between metastasized cells and non-metastasized tumour foci. In addition, N-
acetyl-lactosamine, a specific inhibitor of ECA binding, significantly inhibited the attachment of suspended colon 26 cells to sectioned unfixed normal liver tissue. These results indicate that the expression of
galactose (Gal) beta 1-4
N-acetyl-glucosamine (GlcNAc) residues of branched complex type
sugar chains having specificity for ECA are important for the interaction process of
carcinoma cells with hepatic cells in the process of liver
metastasis.