cdw17-antigen and Colonic-Neoplasms

Glycans play a critical role in physiological and pathological processes through interaction with a variety of ligands. Altered expression and dysregulation of these molecules can cause aberrant cellular function such as malignancy. Glycomics provide information of the structure and function of glycans, glycolipids, and glycoproteins such as proteoglycans, and may help to predict cancer development and progression as biomarkers. In this report, we compared the expression of proteoglycans, the content and structure of glycosaminoglycans and glycolipids between patient-matched normal and cancer tissues obtained from colon cancer patients. Tumor-related proteoglycans, glypican-3, and syndecan-1 showed downregulation in cancer tissues compared to normal tissues. In cancer tissue, the total amount of chondroitin sulfate (CS)/dermatan sulfate and heparan sulfate were lower and, interestingly, the level of disaccharide units of both 4S6S (CS-E) and 6S (CS-C) were higher compared to normal tissue. Also, overall lipids including glycolipids, a major glycomics target, were analyzed by hydrophilic interaction liquid chromatography mass spectrometry. Increase of lyso-phosphatidylcholine (phospholipid), sphingomyelin (sphigolipid), and four types of glycolipids (glucosylceramide, lactosylceramide, monosialic acid ganglioside, and globoside 4) in cancer tissue showed the possibility as potential biomarkers in colon cancer. While requiring the need for careful interpretation, this type of broad investigation gives us a better understanding of pathophysiological roles on glycosaminoglycans and glycolipids and might be a powerful tool for colon cancer diagnosis.

Topics: Adenocarcinoma; Aged; Aged, 80 and over; Antigens, CD; Biomarkers; Carbohydrate Sequence; Case-Control Studies; Chondroitin Sulfates; Colonic Neoplasms; Dermatan Sulfate; Female; Gangliosides; Gene Expression Regulation, Neoplastic; Globosides; Glucosylceramides; Glypicans; Heparitin Sulfate; Humans; Lactosylceramides; Lysophosphatidylcholines; Male; Middle Aged; Molecular Sequence Data; Sphingomyelins; Syndecan-1

In general, an elevated expression of beta 3-galactosyltransferase (beta 3GalT) activity contributed by beta 3GalT5 correlates well with increased biosynthesis and expression of type 1 chain (Gal beta 1-3GlcNAc beta 1-) derivatives such as Lewis A and sialyl Lewis A, which are mostly recognized as terminal epitopes and not further extended. Most known beta 3-N-acetylglucosaminyltransferases show a higher activity toward extending type 2 chain (Gal beta 1-4GlcNAc beta 1-), and an over-expression of beta 3GalT5 could suppress the formation of the type 2 chain poly-N-acetyllactosaminoglycans. The potential of extending instead the predominant type 1 chain termini synthesized under such circumstances was, however, not investigated, partly due to technical difficulty in unambiguous identification of extended type 1 chains. Using an advanced mass spectrometry-based glycomic mapping and glycan sequencing approach, we show here that type 1 chains carried on the lacto-series glycosphingolipids of colonic carcinoma cells can be extended when the endogenous beta 3GalT activity relative to competing beta 4GalT activity, as defined against a common GlcNAc beta 1-3Gal beta 1-4Glc acceptor, is sufficiently high, as found in Colo205 and SW1116, but not in DLD-1 cells. In support of this positive correlation, the lacto-series glycosphingolipids isolated from stably transfected DLD-1 clones over-expressing beta 3GalT5 were shown to comprise fucosylated dimeric type 1 chains, whereas a mock transfectant and the DLD-1 parent carried only fucosylated dimeric type 2 chains on their lactosylceramides. It suggests that while the natural expression of extended type 1 chain is likely to be determined by many contributing factors including the relative amounts of competing glycosyltransferases and the UDP-Gal level, the enhanced expression of beta 3GalT5 is sufficient to promote in vivo extension of type 1 chains by furnishing a significantly higher amount of type 1 chain precursors relative to competing type 2 chains.

Topics: Antigens, CD; Carbohydrate Conformation; Cell Line, Tumor; Colonic Neoplasms; Galactosyltransferases; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Humans; Lactosylceramides; Lewis Blood Group Antigens; Mass Spectrometry; Oligosaccharides

The metabolism of two radiolabelled glycosphingolipids, lactosylceramide and GM1 ganglioside, in differentiated and undifferentiated HT-29 cells is reported. Both lactosylceramide and GM1 ganglioside were demonstrated to be extensively catabolized in undifferentiated cells, as deduced by the relative amount of the compounds formed along the degradative pathway. Conversely, in differentiated cells both precursors were utilized as substrates for sugar-chain elongation. Furthermore we were unable to detect any significant difference in the activity of CMP-NeuAc:GM1 alpha 2-->3 sialyltransferase, a Golgi key enzyme for the glycosylation of glycosphingolipids, between the two cell populations. Taken together with our previous results on the differentiation-dependent trimming of high-mannose N-linked glycoproteins in HT-29 cells, one can suggest that common steps control the anabolic/catabolic balance of these two classes of glycoconjugates as a function of differentiation.

Topics: Antigens, CD; Cell Differentiation; Colonic Neoplasms; G(M1) Ganglioside; Glycosphingolipids; Glycosylation; Golgi Apparatus; Humans; Lactosylceramides; Sialyltransferases; Tumor Cells, Cultured

Monoclonal antibody KH2 (IgM) reactive with lactosyl ceramide and neolactotetraosyl ceramide was applied for the first time to the staining of human cancerous and noncancerous tissues which were fixed with formalin and embedded in paraffin. Digestive-tract cancers originating from stomach, colon, pancreas, gallbladder and bile duct were clearly stained. The staining intensity was especially strong in the apical portion and the intraluminal content of adenocarcinomas. In noncancerous tissues, it was of interest that gastric intestinal metaplasia and certain fetal tissues were stained. A part of the tubules of the kidney, pancreatic ductal cells, lung alveolar epithelial cells and polymorphonuclear leukocytes were stained in normal adult tissues in our study. Enhancement of the intensity of immunostaining by neuraminidase treatment indicated that most of the antigenic determinants should be sialylated and the antigenicity exposed after neuraminidase treatment in several kinds of cancerous and noncancerous tissues. These data suggest that the monoclonal antibody KH2 may be useful in the immunohistologic diagnosis of formalin-fixed human cancerous tissues.

Topics: Antibodies, Monoclonal; Antigens, CD; Antigens, Tumor-Associated, Carbohydrate; Carcinoma; Carcinoma, Hepatocellular; Colonic Neoplasms; Glycosphingolipids; Humans; Immunoenzyme Techniques; Lactosylceramides; Liver Neoplasms; Neoplasms; Neuraminidase; Stomach Neoplasms

Previous studies have indicated that activation of a normally unexpressed beta 1----3-N-acetylglucosaminyltransferase is responsible for the accumulation of a wide diversity of both type 1 and 2 lacto-series antigens in human colonic adenocarcinomas. A beta 1----3-N-acetylglucosaminyltransferase has been solubilized from the human colonic adenocarcinoma cell line SW403 by 0.2% Triton X-100 and some of its properties have been studied. The enzyme was active over a broad pH range from 5.8 to 7.5 and had a strict requirement for Mn2+ as a divalent metal ion. Transfer of N-acetylglucosamine (GlcNAc) to lactosylceramide was optimal when assayed in the presence of a final concentration of Triton CF-54 of 0.3%. Inclusion of CDPcholine in the reaction mixture stimulated the activity by protecting the UDP[14C]GlcNAc from hydrolysis by endogenous enzymes. The kinetic parameters of the enzyme were studied. Km values for acceptors nLc4 and nLc6 were determined to be 0.19 mM for each. However, the Vmax values calculated for these acceptors were 150 and 110 pmol/h/mg protein for nLc4 and nLc6, respectively, suggesting reduced potential for further elongation as the chain length increases. The Km for UDPGlcNAc was determined to be 0.17 mM. Studies of the acceptor specificity have indicated transfer of GlcNAc occurs mainly to type 2 chain nonfucosylated structures. However, elongation of the type 1 chain structure Lc4 was also detected.

Topics: Adenocarcinoma; Antigens, CD; Antigens, Neoplasm; Antigens, Tumor-Associated, Carbohydrate; Cell Line; Chromatography, Thin Layer; Colonic Neoplasms; Detergents; Glucosyltransferases; Glycosphingolipids; Humans; Hydrogen-Ion Concentration; Kinetics; Lactosylceramides; N-Acetylglucosaminyltransferases; Solubility