Increased expression of highly branched N-linked oligosaccharides terminating in N-acetylglucosamine residues in neoplastic and sclerodermal chicken fibroblasts

Abstract

Although neoplastic cells often show a shift towards the expression of larger N-linked oligosaccharides compared to their normal counterparts, little consideration has been given to the possibility that these changes might be a more general phenomenon characteristic of certain neoplastic and non-neoplastic proliferative disorders. Terminal N-acetylglucosamine (GlcNAc) cluster antigen (TGCA) is an immunoreactive epitope(s) of highly branched N-linked oligosaccharides terminating in GlcNAc residues. Here we have compared the expression of this antigen in normal, neoplastic and sclerodermal chicken fibroblasts by immunomorphological methods. TGCA was detectable in only a few, if any, fibroblasts of normal chicken skin or those cultured from chicken embryos. In contrast, the antigen appeared in 15 to 30% of chicken embryo fibroblasts transformed with avian sarcoma viruses and about 50% of neoplastic fibroblasts of both Rous sarcoma virus-induced fibrosarcomas and carcinogen-induced transplantable fibrosarcomas. Significantly, TGCA was also found in most activated fibroblasts in the skin of chickens with hereditary scleroderma. These results indicate that increased expression of highly branched N-linked oligosaccharides terminating in GlcNAc residues is characteristic of both neoplastic and sclerodermal chicken fibroblasts. Investigation of this phenomenon may thus provide insight into biochemical pathways involved in neoplastic transformation and pathogenesis of a number of non-neoplastic proliferative connective tissue disorders such as scleroderma. Moreover, changes in the expression of TGCA-positive oligosaccharides (or their modified biochemical counterparts in mammalian species) may have considerable value for diagnosis of several connective tissue diseases.