title: Enhancement of adhesive property of epithelial cell line Mm2T by culture in the presence of methylated vitamin B12.
abstract: A thymic epithelial cell line Mm2T was cultured in a medium containing a high concentration (100 micrograms/ml) of methylated vitamin B12 (CH3-B12). After 19 days, cells were found to have a flat phenotype, to have lost the floating cells which were observed in the control cells at the confluent stage, and to have acquired a resistance to trypsin. However, treatment of the CH3-B12-treated cells with EDTA resulted in a dissociation of cell-to-cell contact and reaggregation was achieved by addition of Ca2+, indicating the involvement of Ca2+ ion in cell-to-cell contact. Electron microscopic analyses revealed that the CH3-B12-treated cells were nearly square in their vertical section, which was in contrast to the dome-shaped feature of the control cells, and their cell-to-cell contact area was significantly widespread, as compared to those of the control, indicating that Mm2T cells acquires an adhesive property by treatment with CH3-B12. Biochemical analyses of both cells indicated that the concentration of glucosylceramide in the CH3-B12-treated cells was higher than that of the control. Free glucose characteristically inhibited the reattachment of cells dissociated with EDTA, suggesting the involvement of glucose in the cell-to-cell adhesion of CH3-B12-treated cells. In addition, WGA-binding glycoconjugates were intensely observed in the boundary region of CH3-B12-treated cells by immunohistochemical staining, but not in that of the control cells. It is suggested that CH3-B12 may affect the morphological alteration of Mm2T by enhancing cell adhesion through elevated expression of the C-type lectin.
authors.affiliation: Department of Plastic Surgery, Faculty of Medicine, University of Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kitano
authors.forename: T
authors.initials: T
authors.lastname: Takaoka
authors.forename: M
authors.initials: M
authors.lastname: Nakahara
authors.forename: K
authors.initials: K
authors.lastname: Harii
authors.forename: M
authors.initials: M
authors.lastname: Iwamori
mesh_terms: D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects*; D002450:Cell Communication / Q000187:drug effects; D002460:Cell Line; D004848:Epithelium / Q000502:physiology / Q000648:ultrastructure; D008745:Methylation; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D014805:Vitamin B 12 / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D014805:Vitamin B 12