Inhibition by Imatinib of Expression of O-glycan-related Glycosyltransferases and Tumor-associated Carbohydrate Antigens in the K562 Human Leukemia Cell Line

Qi-Chang Sun,Lan Xu,Mi-Bo Liu,Zhi Jiang,Jian-Long Ni,Hong-Jie Shen,Li-Ping Gao,Shi-Liang Wu

doi:10.7314/apjcp.2013.14.4.2447

Qi-Chang Sun, Lan Xu + Show 6 more

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https://doi.org/10.7314/apjcp.2013.14.4.2447

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Abstract

To study changes of tumor associated carbohydrate antigen (TACAs) expression and mRNA levels for tumor associated glycosyltransferases, and assess subcellular localizations of N-acetyl galactosyltransferases (GalNAc-Ts) in the K562 leukemia cell line after imatinib treatment. RT-PCR was performed to analyze the expression of glycosyltransferases which synthesize O-glycan in tumor-associated carbohydrate antigens (TCTAs). The expression of Tn antigen, T antigen and sialyl T antigen on K562 cell membranes was measured by flow cytometry after treatment with different concentrations of imatinib. Co-localization of GalNAc-Ts and ER (endoplasmic reticulum) was determined by confocal laser scanning microcopy. Transcript expression levels of several glycosyltransferases related to TCTAs were decreased after imatinib (0-0.3μM) treatment. Expression of Tn antigen and T antigen was increased while that of sialyl T antigen was decreased. Co-localization of GalNAc-Ts and ER was reduced by 0.2μM of imatinib. Imatinib inhibited the expression of O-glycan related TACAs and several related glycosyltransferases, while decreasing the co-localization of GalNAc-Ts and ER and normalizing O-glycosylation in the K562 human leukemia cell.

Highlights

Chronic myelogenous leukemia (CML) is a neoplastic disease of the hematopoietic stem cells
The tumor associated carbohydrate antigens (TACAs) are synthesized by the specified glycosyltransferases, where the GalNAc-T2 initializes the synthesis of Tn antigen, C1Gal1 catalyzes Tn to T antigen, ST6GalNAc1 catalyzes Tn to Sialyl-Tn antigen, while ST3Gal1, and ST6GalNAc4 catalyzes T antigen to sialyl-T antigen
Slides were coated with polylysine and stored at Disialyl T antigen synthesis in K562 cells was mainly catalyzed by ST6GalNAc4

Summary

Introduction

Chronic myelogenous leukemia (CML) is a neoplastic disease of the hematopoietic stem cells. Objective: To study changes of tumor associated carbohydrate antigen (TACAs) expression and mRNA levels for tumor associated glycosyltransferases, and assess subcellular localizations of N-acetyl galactosyltransferases (GalNAc-Ts) in the K562 leukemia cell line after imatinib treatment. Methods: RT-PCR was performed to analyze the expression of glycosyltransferases which synthesize O-glycan in tumor-associated carbohydrate antigens (TCTAs).

Results

Conclusion