Altered glycosylation of the MUC-1 protein core contributes to the colon carcinoma-associated increase of mucin-bound sialyl-Lewis (x) expression
Hanski, C.; Drechsler, K.; Hanisch, F.G.; Sheehan, J.; Manske, M.; Ogorek, D.; Klussmann, E.; Hanski, M.L.; Blank, M.; Xing, P.X.
Cancer Research 53(17): 4082-4088
1993
ISSN/ISBN: 0008-5472 PMID: 7689422 Document Number: 415049
The mucin carbohydrate epitope sialyl-Le(x), detected with the monoclonal antibody AM-3, is strongly overexpressed in > 90% of human colon carcinomas. We show here that in colon carcinoma one of the mucin cores bearing the sialyl-Le(x) group is MUC-1, whereas sialyl-Le(x) present in normal colon is not detectable on MUC-1. The amounts of MUC-1 core detectable with the monoclonal antibody BC3 in extracts of tumor tissue are 60-180% of those in normal tissue. Two other carbohydrate epitopes located on MUC-1 in mucins from normal and tumor tissue have also been characterized. In contrast to sialyl-Le(x), their expression on MUC-1 is variable and does not correlate with the malignant transformation of colonic mucosa. The transfer of the sialyl-Le(x) group onto the MUC-1 core contributes to the colon carcinoma-associated overexpression of the sialyl-Le(x) epitope.