Comparison of O-Linked Carbohydrate Chains in MUC-1 Mucin from Normal Breast Epithelial Cell Lines and Breast Carcinoma Cell Lines:

doi:10.1074/jbc.271.52.33325

Comparison of O-Linked Carbohydrate Chains in MUC-1 Mucin from Normal Breast Epithelial Cell Lines and Breast Carcinoma Cell Lines:

DEMONSTRATION OF SIMPLER AND FEWER GLYCAN CHAINS IN TUMOR CELLS*

From the ^‡ Immunology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021 and the
^¶ Imperial Cancer Research Fund, Lincoln's Inn Fields, London WC2A 3PX, United Kingdom

^§ To whom correspondence should be addressed: Memorial Sloan-Kettering Cancer Center, 1275 York Ave., New York, NY 10021. Tel.: 212-639-2257; Fax: 212-717-3379.

Abstract

MUC-1 mucin is considered to be aberrantly glycosylated in breast, ovary, and other carcinomas in comparison with mucin from corresponding normal tissues. In order to clarify these differences in glycosylation, we have compared the O-linked carbohydrate chains from MUC-1 immunoprecipitated from [³H]GlcN-labeled breast epithelial cell lines (MMSV1-1, MTSV1-7, and HB-2) derived from cells cultured from human milk, with three breast cancer cell lines (MCF-7, BT-20, and T47D). Analysis by high pH anion chromatography showed that the normal cell lines had a higher ratio of GlcN/GalN and more complex oligosaccharide profiles than the cancer cell lines. Structural analyses were carried out on the oligosaccharides from MTSV1-7 and T47D MUC-1, and the following structures were proposed. MUC-1 from T47D had rather a simple glycosylation pattern, with NeuAcα2-3Galβ1-3GalNAc-ol, Galβ1-3GalNAc-ol, and GalNAc-ol predominating; in contrast, MUC-1 from MTSV1-7 had more complex structures, including a number of disialo, core 2 species, i.e. NeuAcα2-3Galβ1-4GlcNAcβ1-6[NeuAcα2-3Galβ1-3]GalNAc-ol and NeuAcα2-3Galβ1-4GlcNAcβ1-6[NeuAcα2-3Galβ1-4GlcNAcβ1-3Galβ1-3]GalNAc-ol. Double-labeling experiments with [³H]GlcN and ¹⁴C-aminoacids and analysis of GalNAc or GalNAc-ol:protein ratios in MUC-1 showed that there was also a significant difference in the degree of glycosylation of the mucin between the two cell types. We conclude that MUC-1 from breast cancer cell lines has simpler, and fewer, carbohydrate chains than MUC-1 from normal breast epithelial cells, and that these differences, combined or separately, explain the differential tumor specificity of some MUC-1 antibodies and T cells.

Footnotes

↵* This work was supported in part by National Institutes of Health Grants CA-52477 and CA-08748. The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵¹ The abbreviations used are:

mAb

monoclonal antibody

HPAEC

high pH anion exchange chromatography

GalNAc-ol

N-acetylgalactosaminitol

NeuAc(C7)

5-acetamido-3,5-dideoxy-L-arabino-2-heptulosonic acid

g.u.

glucose units

NDV

Newcastle disease virus

FBS

fetal bovine serum

DMEM

Dulbecco's modified Eagle's medium

Mes

2-(N-morpholino)ethanesulfonic acid.
↵² K. O. Lloyd, unpublished data.
- Received August 2, 1996.
- Revision received October 9, 1996.