Tumour suppressor p16(INK4a) - anoikis-favouring decrease in N/O-glycan/cell surface sialylation by down-regulation of enzymes in sialic acid biosynthesis in tandem in a pancreatic carcinoma model

• Published in: The FEBS journal 2012-11, Vol.279 (21), p.4062-4080
• Main Authors: Amano, Maho, Eriksson, Hanna, Manning, Joachim C, Detjen, Katharina M, André, Sabine, Nishimura, Shin-Ichiro, Lehtiö, Janne, Gabius, Hans-Joachim
• Format: Article
• Language: English
• Subjects: Anoikis; Carbohydrate Epimerases - metabolism; Cell Membrane - metabolism; Cyclin-Dependent Kinase Inhibitor p16 - metabolism; Galectin 1 - metabolism; Gene Expression Regulation, Enzymologic; Genes, Tumor Suppressor; Glycosylation; Humans; Lectins - metabolism; Medicin och hälsovetenskap; N-Acetylneuraminic Acid - metabolism; Pancreatic Neoplasms - metabolism; Pancreatic Neoplasms - pathology; Phosphotransferases (Alcohol Group Acceptor) - metabolism; Polysaccharides - metabolism; Proteome; Spectrometry, Mass, Electrospray Ionization
• ISSN: 1742-4658; 1742-4658
• DOI: 10.1111/febs.12001

Tumour suppressor p16(INK4a) is known to exert cell-cycle control via cyclin-dependent kinases. An emerging aspect of its functionality is the orchestrated modulation of N/O-glycosylation and galectin expression to induce anoikis in human Capan-1 pancreatic carcinoma cells. Using chemoselective N/O-glycan enrichment technology (glycoblotting) and product characterization, we first verified a substantial decrease in sialylation. Tests combining genetic (i.e. transfection with α2,6-sialyltransferase-specific cDNA) or metabolic (i.e. medium supplementation with N-acetylmannosamine to track down a bottleneck in sialic acid biosynthesis) engineering with cytofluorometric analysis of lectin binding indicated a role of limited substrate availability, especially for α2,6-sialylation, which switches off reactivity for anoikis-triggering homodimeric galectin-1. Quantitative MS analysis of protein level changes confirmed an enhanced galectin-1 presence along with an influence on glycosyltransferases (β1,4-galactosyltransferase-IV, α2,3-sialyltransferase-I) and detected p16(INK4a) -dependent down-regulation of two enzymes in the biosynthesis pathway for sialic acid [i.e. the bifunctional UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE) and N-acetylneuraminic acid 9-phosphate synthase] (P