title: Susceptibility to proteases of anti-Tn-antigen MLS128 binding glycoproteins expressed in human colon cancer cells.
abstract: Anti-Tn antigen MLS128 monoclonal antibody was produced two decades ago by immunizing mice with "cancerous antigens" derived from LS180 colon cancer cells. Previous studies demonstrated that MLS128 bound to 110 kDa glycoprotein (GP) in colon cancer cells, thereby inhibiting cell growth. Extensive attempts have been made towards understanding the inhibitory action of MLS128 on colon cancer cell growth and solving the primary structure of 110 kDa GP. Since limited proteolysis of 110 kDa GP was observed in microdomain fractions that had been kept frozen for several years, susceptibility of 110 kDa GP to trypsin and other proteases as well as N-glycosidase F has been investigated. Furthermore, 110 kDa GP expression was examined in colon cancer cells independently cultured in Akiyama laboratory. In summary, 110 kDa GP contains N-glycans. It does not contain inter-disulfide bonds but appears to have intra-disulfides. It must contain multiple cleavage sites for trypsin and thermolysin since these proteases digested 110 kDa GP to MLS128-undetectable small fragments. It seems to contain cleavage sites for cathepsin D which could cause limited digestion. LS180 cells derived from Akiyama laboratory produced a limited proteolysis product-like 75 kDa GP. This study provides a structural basis for developing cancer diagnostics and therapeutics.
authors: Department of Applied Biochemistry, Tokai University School of Engineering.
authors: Fumie
authors: F
authors: Oura
authors: Yukiko
authors: Y
authors: Yajima
authors: Munehiro
authors: M
authors: Nakata
authors: Kenzui
authors: K
authors: Taniue
authors: Tetsu
authors: T
authors: Akiyama
authors: Hiroshi
authors: H
authors: Nakada
authors: Kazuo
authors: K
authors: Yamamoto
authors: Yoko
authors: Y
authors: Fujita-Yamaguchi
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology*; D015295:Antigens, Tumor-Associated, Carbohydrate / Q000276:immunology*; D015153:Blotting, Western; D003110:Colonic Neoplasms / Q000201:enzymology / Q000378:metabolism*; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D019073:HT29 Cells; D006801:Humans; D010447:Peptide Hydrolases / Q000494:pharmacology*; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase / Q000494:pharmacology; D011485:Protein Binding; D014357:Trypsin / Q000494:pharmacology
chemical_list: D000911:Antibodies, Monoclonal; D015295:Antigens, Tumor-Associated, Carbohydrate; D006023:Glycoproteins; C040286:Tn antigen; D010447:Peptide Hydrolases; D014357:Trypsin; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase