Abstract
The presence of sugar receptors on human myeloid leukemia cells was comparatively assessed by a highly sensitive binding assay, employing a panel of 14 types of neoglycoenzymes (chemically glycosylated Escherichia coli beta-galactosidase). The selected carbohydrate ligands mainly encompass common components of natural glycoconjugates as mono- or disaccharides. The monocytoid cells of the THP-1 line, the very young myeloblasts and the myeloblasts of the lines KG-1a and KG-1, the promyelocytes of the HL-60 line, and the early myeloblasts/erythroblasts of the K-562 line displayed a nonuniform pattern of specific binding with quantitative differences at a fixed, nonsaturating concentration of the probes. Scatchard analysis in four cases corroborated the indication of cell-type-related differences between the various cell lines. To test whether the detectable cellular sugar-binding sites can mediate adhesion to glycoligands, a rather simple model matrix of nitrocellulose-immobilized neoglycoproteins was first used. In comparison to the carbohydrate-free carrier protein significant cell adhesion was observed primarily with neoglycoproteins that exposed galactose, N-acetylgalactosamine, N-acetylglucosamine, mannose, and fucose moieties among the 11 tested types of carbohydrate residue. Subsequently, human bone marrow stromal cell layers were tested as a model matrix with increased levels of physiological relevance and complexity. Mixtures of carbohydrate and neoglycoprotein were employed as inhibitors of an interaction via lectins between the stromal and the tumor cells. The carbohydrate-dependent alterations of this parameter revealed cell-type-associated properties. Tumor cell binding was significantly decreased for not more than two lines with the effective sugars, namely N-acetylgalactosamine, mannose, fucose, and sialic acid.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.