title: Anti-tumor effect of the anti-KL-6/MUC1 monoclonal antibody through exposure of surface molecules by MUC1 capping.
abstract: Human polymorphic epithelial mucin (MUC1) is a heavily glycosylated large protein that is frequently overexpressed on the surface of many human adenocarcinomas. Studies using monoclonal antibodies (mAb) identified MUC1 as a tumor-associated antigen that has been intensely studied as a target for cancer immunotherapy. We previously identified a mouse IgG(1) mAb that recognizes a sialylated sugar chain, designated as KL-6, classified in 'Cluster 9 (MUC1)'. Using the anti-KL-6 mAb, we investigated antitumor effects of anti-MUC1 mAb on breast cancer cell lines expressing MUC1 abundantly. We showed that anti-KL-6 mAb induced capping of MUC1 and facilitated E-cadherin-mediated cell-cell interaction in the breast cancer cell lines YMB-S and ZR-75-1S, which proliferate in suspension culture without aggregation. Moreover, anti-KL-6 mAb enhanced the cytotoxic activity of lymphokine-activated killer cells. These results indicate that the capping of MUC1 restores cell surface proteins, such as adhesion molecules and tumor antigens, to work in cell-cell interactions, leading to inhibition of tumor proliferation due to cell-cell adhesion and increased accessibility to effector cells that are needed to kill tumor cells.
authors.affiliation: Department of Molecular and Internal Medicine, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
authors.forename: Mihoko
authors.initials: M
authors.lastname: Doi
authors.forename: Akihito
authors.initials: A
authors.lastname: Yokoyama
authors.forename: Keiichi
authors.initials: K
authors.lastname: Kondo
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ohnishi
authors.forename: Nobuhisa
authors.initials: N
authors.lastname: Ishikawa
authors.forename: Noboru
authors.initials: N
authors.lastname: Hattori
authors.forename: Nobuoki
authors.initials: N
authors.lastname: Kohno
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D000951:Antigens, Neoplasm; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001943:Breast Neoplasms / Q000276:immunology / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects / Q000276:immunology; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D003602:Cytotoxicity, Immunologic; D005260:Female; D018922:HL-60 Cells; D006801:Humans; D007152:Immunologic Capping; D020014:K562 Cells; D015979:Killer Cells, Lymphokine-Activated; D051379:Mice; D018396:Mucin-1; D009077:Mucins / Q000276:immunology* / Q000378:metabolism / Q000494:pharmacology; D014162:Transfection
chemical_list: D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D000970:Antineoplastic Agents; C060192:MUC1 protein, human; D018396:Mucin-1; D009077:Mucins