title: Deacetylase activity of human tumor cells producing immunosuppressive aminosugars: its possible role in resistance to cell-mediated cytotoxicity.
abstract: In the present study, we examined the presence of deacetylases capable of producing free hexosamines, which we have shown earlier to be immunosuppressive against human natural killer (NK) cell-mediated cytotoxicity, from N-acetylhexosamines in human tumor cells. When human NK-resistant colon cancer cells (Colo-320DM) were incubated with acetyl-D-[1,6-3H(N)]glucosamine, a significant conversion to [3H]glucosamine occurred. Deacetylation was demonstrated as a change of the substrate radioactivity into free glucosamine trapped by a cation exchange resin, and this was subsequently confirmed by paper chromatography. This deacetylase activity was detected in other NK-resistant tumor cell lines, especially in freshly isolated human renal and breast cancer cells and testicular seminoma cells. However, no deacetylase activity was detected in NK-sensitive target cells such as K562, MOLT-4, or HL-60 cells. The ability to produce free hexosamines from N-acetylated aminosugars may provide a new mechanism for the escape of tumor cells from the attack of immune effector cells such as NK cells.
authors.affiliation: Department of Internal Medicine, Tazuke-Kofukai Medical Research Institute, Kitano Hospital, Osaka, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Yagita
authors.forename: A
authors.initials: A
authors.lastname: Seppo
authors.forename: O
authors.initials: O
authors.lastname: Renkonen
authors.forename: E
authors.initials: E
authors.lastname: Saksela
mesh_terms: D000117:Acetylglucosamine / Q000494:pharmacology; D000581:Amidohydrolases / Q000502:physiology*; D003602:Cytotoxicity, Immunologic; D006595:Hexosamines / Q000378:metabolism*; D006801:Humans; D007166:Immunosuppressive Agents / Q000378:metabolism* / Q000494:pharmacology; D007694:Killer Cells, Natural / Q000276:immunology*; D009174:Mycoplasma / Q000201:enzymology; D009369:Neoplasms / Q000201:enzymology* / Q000276:immunology; D013379:Substrate Specificity; D014407:Tumor Cells, Cultured
chemical_list: D006595:Hexosamines; D007166:Immunosuppressive Agents; D000581:Amidohydrolases; D000117:Acetylglucosamine