title: Glycosidic intermediates identified in 1H MR spectra of intact tumour cells may contribute to the clarification of aspects of glycosylation pathways.
abstract: The glycosylation process, through the addition of carbohydrates, is a major post-translational modification of proteins and glycolipids. Proteins may be glycosylated in either the secretory pathway leading to N-linked or O-linked glycoproteins or as nucleocytoplasmic glycosylation that targets only single proteins involving a single β-linked N-acetylglucosamine. In both cases, the key precursors are the uridine diphospho-N-acetylhexosamines synthesised by the hexosamine biosynthetic pathway. Furthermore, uridine diphospho-N-acetylglucosamine participates in the biosynthesis of sialic acid. In this work, we propose MRS for the detection of uridine diphospho-N-acetylhexosamines visible in high-resolution MR spectra of intact cells from different human tumours. Signals from the nucleotide and amino sugar moieties, including amide signals observed for the first time in whole cells, are assigned, also taking advantage of spectral changes that follow cell treatment with ammonium chloride. Finally, parallel changes in uridine diphospho-N-acetylhexosamines and glutamine pools, observed after pH changes induced by ammonium chloride in the different tumour cell lines, may provide more details on the glycosylation processes.
authors.affiliation: Dipartimento di Tecnologie e Salute and INFN Gruppo Collegato Sanità, Istituto Superiore di Sanità, Rome, Italy. sveva.grande@iss.it
authors.forename: Sveva
authors.initials: S
authors.lastname: Grande
authors.forename: Alessandra
authors.initials: A
authors.lastname: Palma
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Luciani
authors.forename: Antonella
authors.initials: A
authors.lastname: Rosi
authors.forename: Laura
authors.initials: L
authors.lastname: Guidoni
authors.forename: Vincenza
authors.initials: V
authors.lastname: Viti
mesh_terms: D053898:Biosynthetic Pathways / Q000187:drug effects; D045744:Cell Line, Tumor; D006027:Glycosides / Q000032:analysis*; D006031:Glycosylation / Q000187:drug effects; D006801:Humans; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D009369:Neoplasms / Q000378:metabolism*; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011522:Protons; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology; D014537:Uridine Diphosphate N-Acetylglucosamine / Q000737:chemistry / Q000378:metabolism
chemical_list: D006027:Glycosides; D011522:Protons; D000644:Quaternary Ammonium Compounds; D014537:Uridine Diphosphate N-Acetylglucosamine