Differential expression of N-linked oligosaccharides in methotrexate-resistant primary central nervous system lymphoma cells

Yasuo Takashima,Azusa Hayano,Kazuhiro Ikenaka,Ryuya Yamanaka,Yuichiro Kano,Hiroaki Hondoh,Takeshi Yoshimura

doi:10.1186/s12885-019-6129-8

Abstract

BackgroundOligosaccharides of glycoprotein, particularly negatively-charged sialylated N-glycans, on the surface of lymphomas play important roles in cell–cell interactions and bind immunoglobulin-like lectins, causing inflammatory responses and bioregulation. However, their characterizations have largely been unknown in central nervous system (CNS) lymphoma.MethodsHere, we investigated expression patterns of N-linked oligosaccharides of glycoproteins in cells derived from CNS lymphomas and clinical specimens.ResultsWe first generated methotrexate (MTX)-resistant cells derived from HKBML and TK as CNS lymphoma, and RAJI as non-CNS lymphoma and determined N-linked oligosaccharide structures in these cells and other non-CNS lymphoma-derived cells including A4/FUK, OYB, and HBL1. Major components of the total oligosaccharides were high-mannose type N-glycans, whose level increased in MTX-resistant HKBML and TK but decreased in MTX-resistant RAJI. We also detected sialylated biantennary galactosylated N-glycans with α1,6-fucosylation, A2G2F, and A2G2FB from HKBML, TK, and RAJI. Sialylated A4G4F was specifically isolated from RAJI. However, the ratios of these sialylated N-glycans slightly decreased against MTX-resistant compared to non-resistant cells. Interestingly, almost all complex-type oligosaccharides were α2,6-sialylated.DiscussionThis is the first study for the expression profile of N-oligosaccharides on MTX-resistant primary CNS lymphoma-derived cells HKBML and TK, and tumor tissues resected from patients with CNS lymphoma,ConclusionThese results propose a possibility that the differential expression of high-mannose types and sialylated A2G2F, A2G2FB, and A4G4F on the surface of CNS lymphomas may provide a hint for targets for diagnoses and treatments of the oligosaccharide type-specific lymphomas.

Highlights

Oligosaccharides of glycoprotein, negatively-charged sialylated N-glycans, on the surface of lymphomas play important roles in cell–cell interactions and bind immunoglobulin-like lectins, causing inflammatory responses and bioregulation
The increased β1, 6-GlcNAc-bearing N-glycan expression is co-regulated by N-acetyl glucosaminyl transferases V (GnT-V) and the Ets-1 transcription factor, and the branching complex type N-glycans function in glioma invasivity [16]
Expression of A2G2F, A2G2FB, and A4G4F almost did not change in Sialylated N-linked oligosaccharides of glycoproteins in clinical specimens of central nervous system (CNS) lymphoma We further investigated the expression of N-linked oligosaccharides of glycoprotein in tumor tissues derived from three primary and one secondary CNS lymphoma specimens (Additional file 1: Table S1), and detected 53– 67% of the total oligosaccharides in the specimens (Fig. 4a)

Summary

Introduction

Oligosaccharides of glycoprotein, negatively-charged sialylated N-glycans, on the surface of lymphomas play important roles in cell–cell interactions and bind immunoglobulin-like lectins, causing inflammatory responses and bioregulation. Their characterizations have largely been unknown in central nervous system (CNS) lymphoma. Several studies have clarified that the structures of Nlinked oligosaccharide chains on glycoproteins have been involved in tumor cell adhesion to the extracellular matrix (ECM), metastatic potentials, and cell proliferation and differentiation [8, 10,11,12,13,14,15]. The oligosaccharides on the primary central nervous system (CNS) lymphoma (PCNSL) surface have largely been unknown

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