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: Paul R Wratil, Stephan Rigol, Barbara Solecka, Guido Kohla, Christoph Kannicht, Werner Reutter, Athanassios Giannis, Long D Nguyen
• Journal: The Journal of biological chemistry (J Biol Chem) Vol. 289 Issue 46 Pg. 32056-32063 (Nov 14 2014) ISSN: 1083-351X [Electronic] United States
• PMID: 25278018 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Chemical References

• Carrier Proteins
• Hexosamines
• Lectins
• Phosphotransferases (Alcohol Group Acceptor)
• N-acetylglucosamine kinase
• Carbohydrate Epimerases
• UDP acetylglucosamine-2-epimerase
• N-acyl-D-glucosamine 2-epimerase
• N-Acetylneuraminic Acid
• N-acetylmannosamine

Topics

• Carbohydrate Epimerases (chemistry)
• Carrier Proteins (chemistry)
• Chromatography, High Pressure Liquid
• Cloning, Molecular
• Cytosol (metabolism)
• Dose-Response Relationship, Drug
• Flow Cytometry
• Hexosamines (chemistry)
• Humans
• Jurkat Cells
• Kinetics
• Lectins
• N-Acetylneuraminic Acid (chemistry)
• Phosphotransferases (Alcohol Group Acceptor) (chemistry)
• Protein Binding
• Scattering, Radiation
• Substrate Specificity
• Surface Plasmon Resonance