Analysis of cell-surface sugar receptor expression by neoglycoenzyme binding and adhesion to plastic-immobilized neoglycoproteins for related weakly and strongly metastatic cell lines of murine tumor model systems

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Abstract
Recognition of the carbohydrate part of cellular glycoconjugates by cell‐surface sugar receptors may contribute to interactions, essential to the establishment of metastases. Comparison of the properties of strongly metastatic variants to their related, less metastatic counterparts offers a generally accepted approach to the discovery of metastasisassociated characteristics. The chemically induced murine lymphoma line Eb and its spontaneously arising variant ESb with increased potential for lung and liver colonization, the virally induced lymphosarcoma cell line RAW 117‐P and its in vivo selected variant H 10 with increased potential for liver colonization, and the B16‐FI melanoma line and its in vivo selected variant F 10 with increased potential for lung colonization, were chosen. A panel of 12 types of chemically glycosylated E. coli β‐galactosidase, exposing the pivotal carbohydrate residues for specific carbohydrate‐dependent cell binding, was employed to study the expression of respective cellsurface sugar receptors on these cell lines. Specific binding occurred in a non‐uniform manner for the individual probes. Systematic measurements at a non‐saturating ligand concentration revealed quantitative differences between the 2 cell lines of each system. However, there were no consistent changes associated with the metastatic phenotype. A similar result was obtained employing Scatchard analyses for quantitative evaluation of binding characteristics in several cases. Surface receptor expression was responsive to chemical induction of differentiation in the lymphosarcoma model. Analyses of sugar‐inhibitable cell adhesion to neoglycoproteincoated plastic wells for the lymphoma and lymphosarcoma cells revealed that the presence of cell‐surface sugar receptors, even at similar densities to those defined by neoglycoenzyme binding, will not necessarily translate into an identical adhesive response. Several carbohydrates, especially N‐acetyl‐D‐galactosamine, can differentially affect this interaction at a non‐toxic concentration in both model systems.