title: Identification of mono- and disulfated N-acetyl-lactosaminyl Oligosaccharide structures as epitopes specifically recognized by humanized monoclonal antibody HMOCC-1 raised against ovarian cancer.
abstract: A humanized monoclonal antibody raised against human ovarian cancer RMG-I cells and designated as HMOCC-1 (Suzuki, N., Aoki, D., Tamada, Y., Susumu, N., Orikawa, K., Tsukazaki, K., Sakayori, M., Suzuki, A., Fukuchi, T., Mukai, M., Kojima-Aikawa, K., Ishida, I., and Nozawa, S. (2004) Gynecol. Oncol. 95, 290-298) was characterized for its carbohydrate epitope structure. Specifically, a series of co-transfections was performed using mammalian expression vectors encoding specific glycosyltransferases and sulfotransferases. These experiments identified one sulfotransferase, GAL3ST3, and one glycosyltransferase, B3GNT7, as required for HMOCC-1 antigen formation. They also suggested that the sulfotransferase CHST1 regulates the abundance and intensity of HMOCC-1 antigen. When HEK293T cells were co-transfected with GAL3ST3 and B3GNT7 expression vectors, transfected cells weakly expressed HMOCC-1 antigen. When cells were first co-transfected with GAL3ST3 and B3GNT7 and then with CHST1, the resulting cells strongly expressed HMOCC-1 antigen. However, when cells were transfected with a mixture of GAL3ST3 and CHST1 before or after transfection with B3GNT7, the number of antigen-positive cells decreased relative to the number seen with only GAL3ST3 and B3GNT7, suggesting that CHST1 plays a regulatory role in HMOCC-1 antigen formation. Because these results predicted that HMOCC-1 antigens are SO(3) → 3Galβ1 → 4GlcNAcβ1 → 3(±SO(3) → 6)Galβ1 → 4GlcNAc, we chemically synthesized mono- and disulfated and unsulfated oligosaccharides. Immunoassays using these oligosaccharides as inhibitors showed the strongest activity by disulfated tetrasaccharide, weak but positive activity by monosulfated tetrasaccharide at the terminal galactose, and no activity by nonsulfated tetrasaccharides. These results establish the HMOCC-1 epitope, which should serve as a useful reagent to further characterize ovarian cancer.
authors.affiliation: Tumor Microenvironment Program, Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California 920137, USA.
authors.forename: Toshiaki K
authors.initials: TK
authors.lastname: Shibata
authors.forename: Fumiko
authors.initials: F
authors.lastname: Matsumura
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
authors.forename: Shinyi
authors.initials: S
authors.lastname: Yu
authors.forename: Chi-Chi
authors.initials: CC
authors.lastname: Chou
authors.forename: Kay-Hooi
authors.initials: KH
authors.lastname: Khoo
authors.forename: Kazuko
authors.initials: K
authors.lastname: Kitayama
authors.forename: Tomoya O
authors.initials: TO
authors.lastname: Akama
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Sugihara
authors.forename: Naohiro
authors.initials: N
authors.lastname: Kanayama
authors.forename: Kyoko
authors.initials: K
authors.lastname: Kojima-Aikawa
authors.forename: Peter H
authors.initials: PH
authors.lastname: Seeberger
authors.forename: Minoru
authors.initials: M
authors.lastname: Fukuda
authors.forename: Atsushi
authors.initials: A
authors.lastname: Suzuki
authors.forename: Daisuke
authors.initials: D
authors.lastname: Aoki
authors.forename: Michiko N
authors.initials: MN
authors.lastname: Fukuda
mesh_terms: D000606:Amino Sugars / Q000138:chemical synthesis / Q000276:immunology*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity / Q000276:immunology*; D016466:CHO Cells; D002240:Carbohydrate Sequence; D006224:Cricetinae; D004220:Disulfides / Q000138:chemical synthesis / Q000276:immunology; D018604:Epitope Mapping; D000939:Epitopes / Q000276:immunology*; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D008969:Molecular Sequence Data; D017351:N-Acetylglucosaminyltransferases / Q000235:genetics / Q000378:metabolism; D019158:N-Acetylneuraminic Acid / Q000378:metabolism; D009844:Oligosaccharides / Q000138:chemical synthesis / Q000276:immunology*; D010051:Ovarian Neoplasms / Q000276:immunology* / Q000473:pathology; D034741:RNA, Small Interfering / Q000494:pharmacology; D015238:Sulfotransferases / Q000235:genetics / Q000378:metabolism; D014407:Tumor Cells, Cultured; D000097811:Carbohydrate Sulfotransferases
chemical_list: D000606:Amino Sugars; D000911:Antibodies, Monoclonal; D004220:Disulfides; D000939:Epitopes; D017351:N-Acetylglucosaminyltransferases; D019158:N-Acetylneuraminic Acid; D009844:Oligosaccharides; D034741:RNA, Small Interfering; D015238:Sulfotransferases; D000097811:Carbohydrate Sulfotransferases; C000458:N-acetyllactosamine; C499227:B3GNT7 protein, human; C432916:galactose-3-O-sulfotransferase 3