N-glycan alterations are associated with drug resistance in human hepatocellular carcinoma

Takeaki Kudo,Hiroaki Nakagawa,Shin-Ichiro Nishimura,Satoru Todo,Takahito Nakagawa,Kisaburo Deguchi,Naoya Kamiyama,Masato Takahashi,Hideki Yokoo,Kazuaki Nakanishi,Jun Hamaguchi,Toshiya Kamiyama

doi:10.1186/1476-4598-6-32

Takeaki Kudo, Hiroaki Nakagawa + Show 10 more

Open Access

https://doi.org/10.1186/1476-4598-6-32

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Abstract

BackgroundCorrelations of disease phenotypes with glycosylation changes have been analysed intensively in the tumor biology field. Glycoforms potentially associated with carcinogenesis, tumor progression and cancer metastasis have been identified. In cancer therapy, drug resistance is a severe problem, reducing therapeutic effect of drugs and adding to patient suffering. Although multiple mechanisms likely underlie resistance of cancer cells to anticancer drugs, including overexpression of transporters, the relationship of glycans to drug resistance is not well understood.ResultsWe established epirubicin (EPI) – and mitoxantrone (MIT) – resistant cell lines (HLE-EPI and HLE-MIT) from the human hepatocellular carcinoma cell line (HLE). HLE-EPI and HLE-MIT overexpressed transporters MDR1/ABCB1 and BCRP/ABCG2, respectively. Here we compared the glycomics of HLE-EPI and HLE-MIT cells with the parental HLE line. Core fucosylated triantennary oligosaccharides were increased in the two resistant lines. We investigated mRNA levels of glycosyltransferases synthesizing this oligosaccharide, namely, N-acetylglucosaminyltransferase (GnT)-IVa, GnT-IVb and α1,6-fucosyltransferase (α1,6-FucT), and found that α1,6-FucT was particularly overexpressed in HLE-MIT cells. In HLE-EPI cells, GnT-IVa expression was decreased, while GnT-IVb was increased. Both GnT-IVs were downregulated in HLE-MIT cells. HLE-MIT cells also showed decreases in fucosylated tetraantennary oligosaccharide, the product of GnT-V. GnT-V expression was decreased in both lines, but particularly so in HLE-MIT cells. Thus both N-glycan and glycosyltransferase expression was altered as cells acquired tolerance, suggesting novel mechanisms of drug resistance.ConclusionN-glycan and glycosyltransferase expression in HLE-EPI and HLE-MIT were analysed and presented that glycans altered according with acquired tolerance. These results suggested novel mechanisms of drug resistance.

Highlights

Correlations of disease phenotypes with glycosylation changes have been analysed intensively in the tumor biology field
Yamashita et al reported that products of N-acetylglucosaminyltransferase (GnT)-IV, GnT-V and α1,6-fucosyltransferase (α1,6-FucT) are all increased in hepatocellular carcinoma [3]
Separated sample peaks were analyzed on amide columns, and structures of oligosaccharides contained in each peak were determined using 2-dimensional mapping (2-DM) strategies

Summary

Introduction

Correlations of disease phenotypes with glycosylation changes have been analysed intensively in the tumor biology field. Glycoforms potentially associated with carcinogenesis, tumor progression and cancer metastasis have been identified. Multiple mechanisms likely underlie resistance of cancer cells to anticancer drugs, including overexpression of transporters, the relationship of glycans to drug resistance is not well understood. One cause of resistance is elevated expression or activity of ATP-binding cassette (ABC) transporters, such as multidrug resistant protein 1 (MDR1/ABCB1) and breast cancer resistance protein (BCRP/ABCG2). Both transporters are membrane glycoproteins containing Nglycans. Many studies show that alterations in N-linked oligosaccharides of tumor cells are associated with carcinogenesis, invasion and metastasis [1,2]. The relationship between chemoresistance and N-glycans has been investigated in very few studies

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