Xenografts from a human colon carcinoma and its metastases: establishment, characterization and differences in the pattern of carbohydrate-binding proteins

Investigation of the pathogenesis of human colorectal carcinoma metastasis can be rendered experimentally possible by suitable human cell biological model systems. The purpose of these studies was to establish xenografts in nude mice from human colon carcinoma and from its metastasis in the same patient as an appropriate model. Surgically removed biopsy specimens from a colon adenocarcinoma (grade 3) and its local relapse two years later with metastases in the small intestine were established as xenotransplants and their growth characteristics examined. Both tissue types shared common characteristics with respect to marker expression (carcinoembryonic antigen, neuron-specific enolase, cytokeratin). The primary tumor showed remarkable development of necrotic effusion with cytotoxic activity that ceased after several passages. The profile of endogenous carbohydrate-binding proteins (lectins), the receptors for cellular glycoconjugates in a recognitive protein-carbohydrate interplay with potential relevance to metastases formation, revealed differences between these two human tumor samples of identical origin, especially with respect to beta-galactoside-specific receptors. This glycobiochemical analysis employed standardized procedures. Prolonged passaging was also shown to result in profile alterations, as was similarly noted in comparison to another species. These studies may encourage the application of systems of primary tumor and its metastases in the same patient in attempts to correlate the expression of cellular characteristics with the biological and clinical behavior of human colonic tumor cells.