Proteomic and Postproteomic Characterization of Keratan Sulfate-Glycanated Isoforms of Thyroglobulin and Transferrin Uniquely Elaborated by Papillary Thyroid Carcinomas

Abstract

Previous studies have suggested that surface components of papillary thyroid carcinoma (PTC) cells may be aberrantly glycanated, but the precise nature of these molecules has not been unveiled nor documented to be of clinical relevance. A monoclonal antibody was raised against a unique keratan sulfate (KS) determinant and used to differentially screen benign and malignant thyroid tissue for the expression of components carrying these moieties. In a total of 349 cases of benign and malignant thyroid lesions, 100% of the 115 PTC cases examined (including various histological subtypes) were found to contain KSbearing molecules, whereas these were virtually absent from benign tissues and other thyroid tumors, with the exception of 21% of the follicular carcinoma cases analyzed. A composite immunoaffinity chromatography, immunochemistry, and mass spectrometric approach revealed that the PTC-specific KS-bearing macromolecules were unique glycoforms of thyroglobulin and transferrin. Combined, reciprocal immunoprecipitation and Western blotting further indicated that the former glycoform predominated and that most of the transferrin produced by PTC was glycanated with KS moieties. Fluorescent keratanase II-based fingerprinting of the KS moieties bound to these isoforms further demonstrated several PTC-specific peculiarities: 1) that a considerable portion of the moieties was covalently attached via a novel core protein linkage structure; 2) they had an unusual extended average length; 3) an unusual relative ratio of highly sulfated disaccharides terminating with ␣ Papillary thyroid carcinoma (PTC) is by far the most frequent malignant tumor of the thyroid with a threefold prevalence in females.

Identification and characterization of sulfated glycoproteins from small cell lung carcinoma cells assisted by management of molecular charges

“…Many reports have shown that proteins containing sulfated glycans (i.e., sulfated glycoproteins) are associated with various diseases, such as cancer [1,2], cystic fibrosis [3,4], and osteoarthritis [5][6][7]. Most of these reports have indirectly demonstrated the presence of sulfated glycoproteins by experiments using sulfotransferase genes, specific antibodies for a particular sulfated glycans, and/or radioisotope [ 35 SO 4 ] labeling [8][9][10].…”

Characterization of thyroid 'follicular neoplasms' in fine-needle aspiration cytological specimens using a panel of immunohistochemical markers: a proposal for clinical application

“…Keratan-sulphate (KS) is a glycoprotein complex having an unusual relative ratio of highly sulphated disaccharides and carrying a novel non-characterized oligosaccharide moiety at the non-reducing terminus, which is recognized by the monoclonal antibody 373E1 (Magro et al 2003). This aberrant glycoprotein complex has been found almost exclusively in thyroid papillary carcinomas.…”

“…This aberrant glycoprotein complex has been found almost exclusively in thyroid papillary carcinomas. Moreover, it has been reported that papillary carcinoma-specific KS-bearing macromolecules are unique glycoforms of thyroglobulin and transferrin (Magro et al 2003). The peculiar KS epitope has been proposed as a novel marker for the differential diagnosis of benign and malignant thyroid tumours (Magro et al 2003).…”

Thyroglobulin Autoantibodies, Thyroid Nodules, and New Insights Into Some Old Questions

“…However, the authors' speculation that thyroglobulin (Tg) in thyroid cancer patients might differ from ordinary Tg, potentially rendering it more immunogenic, is supported by several previous publications since the 1980s through to the more recent past (6,7). Whether such increased Tg immunogenicity would translate into different epitope recognition patterns remains Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota.…”