title: A novel approach to decrease sialic acid expression in cells by a C-3-modified N-acetylmannosamine.
abstract: Due to its position at the outermost of glycans, sialic acid is involved in a myriad of physiological and pathophysiological cell functions such as host-pathogen interactions, immune regulation, and tumor evasion. Inhibitors of cell surface sialylation could be a useful tool in cancer, immune, antibiotic, or antiviral therapy. In this work, four different C-3 modified N-acetylmannosamine analogs were tested as potential inhibitors of cell surface sialylation. Peracetylated 2-acetylamino-2-deoxy-3-O-methyl-D-mannose decreases cell surface sialylation in Jurkat cells in a dose-dependent manner up to 80%, quantified by flow cytometry and enzyme-linked lectin assays. High-performance liquid chromatography experiments revealed that not only the concentration of membrane bound but also of cytosolic sialic acid is reduced in treated cells. We have strong evidence that the observed reduction of sialic acid expression in cells is caused by the inhibition of the bifunctional enzyme UDP-GlcNAc-2-epimerase/ManNAc kinase. 2-Acetylamino-2-deoxy-3-O-methyl-D-mannose inhibits the human ManNAc kinase domain of the UDP-GlcNAc-2-epimerase/ManNAc kinase. Binding kinetics of the inhibitor and human N-acetylmannosamine kinase were evaluated using surface plasmon resonance. Specificity studies with human N-acetylglucosamine kinase and hexokinase IV indicated a high specificity of 2-acetylamino-2-deoxy-3-O-methyl-D-mannose for MNK. This substance represents a novel class of inhibitors of sialic acid expression in cells, targeting the key enzyme of sialic acid de novo biosynthesis.
authors.affiliation: Institut für Laboratoriumsmedizin, Klinische Chemie, und Pathobiochemie, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Arnimallee 22, D-14195 Berlin-Dahlem.
authors.forename: Paul R
authors.initials: PR
authors.lastname: Wratil
authors.affiliation: Institut für Organische Chemie, Universität Leipzig, Fakultät für Chemie und Mineralogie, Johannisallee 29, D-04103 Leipzig, and.
authors.forename: Stephan
authors.initials: S
authors.lastname: Rigol
authors.affiliation: Octapharma R&D, Molecular Biochemistry Berlin, Walther-Nernst-Strasse 3, D-12489 Berlin, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Solecka
authors.affiliation: Octapharma R&D, Molecular Biochemistry Berlin, Walther-Nernst-Strasse 3, D-12489 Berlin, Germany.
authors.forename: Guido
authors.initials: G
authors.lastname: Kohla
authors.affiliation: Octapharma R&D, Molecular Biochemistry Berlin, Walther-Nernst-Strasse 3, D-12489 Berlin, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Kannicht
authors.affiliation: Institut für Laboratoriumsmedizin, Klinische Chemie, und Pathobiochemie, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Arnimallee 22, D-14195 Berlin-Dahlem.
authors.forename: Werner
authors.initials: W
authors.lastname: Reutter
authors.affiliation: Institut für Organische Chemie, Universität Leipzig, Fakultät für Chemie und Mineralogie, Johannisallee 29, D-04103 Leipzig, and. Electronic address: giannis@uni-leipzig.de.
authors.forename: Athanassios
authors.initials: A
authors.lastname: Giannis
authors.affiliation: Institut für Laboratoriumsmedizin, Klinische Chemie, und Pathobiochemie, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Arnimallee 22, D-14195 Berlin-Dahlem,. Electronic address: long-duc.nguyen@charite.de.
authors.forename: Long D
authors.initials: LD
authors.lastname: Nguyen
mesh_terms: D002238:Carbohydrate Epimerases / Q000737:chemistry*; D002352:Carrier Proteins / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D003600:Cytosol / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D006595:Hexosamines / Q000737:chemistry*; D006801:Humans; D019169:Jurkat Cells; D007700:Kinetics; D037102:Lectins; D019158:N-Acetylneuraminic Acid / Q000737:chemistry*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000737:chemistry; D011485:Protein Binding; D012542:Scattering, Radiation; D013379:Substrate Specificity; D020349:Surface Plasmon Resonance
chemical_list: D002352:Carrier Proteins; D006595:Hexosamines; D037102:Lectins; D017853:Phosphotransferases (Alcohol Group Acceptor); C018716:N-acetylglucosamine kinase; D002238:Carbohydrate Epimerases; C100033:UDP acetylglucosamine-2-epimerase; C024519:N-acyl-D-glucosamine 2-epimerase; D019158:N-Acetylneuraminic Acid; C002022:N-acetylmannosamine
keywords: Enzyme Inhibitor; Flow Cytometry; Glycosylation Inhibitor; High-performance Liquid Chromatography (HPLC); Sialic Acid; Surface Plasmon Resonance (SPR)