title: Molecular characterization of tumor associated antigen in mice exposed to a hepatocarcinogen.
abstract: The present investigation is aimed to identify and characterize tumor-associated antigen (TAA) in animals exposed to hepatocarcinogen. Swiss albino mice showed an enhanced expression of an approximately 58 kDa glycoprotein in liver cells upon exposure to a potential hepatocarcinogen N-nitrosodibutylamine (DBN). Carcinogenesis induction in mice was monitored by assays of y-glutamyl transpeptidase (GGT), acetylcholine esterase (AChE), glutathione-S-transferase (GST) activities and the level of glutathione (GSH) in liver. DBN treated animals showed cell distortion and extensive necrosis as observed by histological examination. The over-expressed TAA was purified by ion-exchange chromatography and further characterized by SDS-PAGE. The carbohydrate contents and glycan linkage to the polypeptide backbone was analyzed by using the DIG glycan differentiation and de-glycosylation kits. The glycoprotein has glycan chains that are N-linked via asparagines to the polypeptide backbone. It was also observed that the molecule is rich in sialic acid residues with a significantly high carbohydrate to protein ratio (> 2:1). The over-expressed high molecular weight glycoprotein TAA was found to be highly immunogenic and could eventually be used to induce immune response in order to counter tumor regression.
authors.affiliation: Immunology Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong 793022, Meghalaya, India. a_alam51@yahoo.com
authors.forename: Anis
authors.initials: A
authors.lastname: Alam
authors.forename: Laishram Indira
authors.initials: LI
authors.lastname: Singha
authors.forename: Vinod
authors.initials: V
authors.lastname: Singh
mesh_terms: D000110:Acetylcholinesterase / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D015295:Antigens, Tumor-Associated, Carbohydrate / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D002241:Carbohydrates / Q000032:analysis; D002273:Carcinogens / Q000633:toxicity; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D005978:Glutathione / Q000378:metabolism; D005982:Glutathione Transferase / Q000187:drug effects / Q000378:metabolism; D006031:Glycosylation; D022781:Hepatocytes / Q000378:metabolism / Q000473:pathology; D006601:Hexoses / Q000032:analysis; D008099:Liver / Q000378:metabolism / Q000473:pathology; D008113:Liver Neoplasms / Q000139:chemically induced / Q000276:immunology* / Q000473:pathology; D008562:Membrane Glycoproteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D051379:Mice; D019158:N-Acetylneuraminic Acid / Q000032:analysis; D009602:Nitrosamines / Q000633:toxicity; D005723:gamma-Glutamyltransferase / Q000187:drug effects / Q000378:metabolism
chemical_list: D015295:Antigens, Tumor-Associated, Carbohydrate; D002241:Carbohydrates; D002273:Carcinogens; D006601:Hexoses; D008562:Membrane Glycoproteins; D009602:Nitrosamines; C012279:dibutylnitrosamine; D005723:gamma-Glutamyltransferase; D005982:Glutathione Transferase; D000110:Acetylcholinesterase; D005978:Glutathione; D019158:N-Acetylneuraminic Acid