title: Phorbol ester-induced shedding of intercellular adhesion molecule-1 (ICAM-1) on erythroleukemic K 562 cells.
abstract: The effect of phorbol 12-myristate 13-acetate (PMA) on the expression and shedding of intercellular adhesion molecule-1 (ICAM-1) was investigated on the hematopoietic cell lines K 562 and U 937 using flow cytometry, fluorescence microscopy and ELISA technique. At low concentration of 1 nM, PMA stimulated the expression of ICAM-1 on the cell surface about 4-fold within 24 h, whereas a short-term treatment with 100 nM PMA led to the shedding of 35% of ICAM-1 from the surface of K 562 cells. The release of surface ICAM-1 was found on single cells by fluorescence microscopy to be a uniform process proceeding within 15 min. The shedding of ICAM-1 correlated with elevated levels of sICAM-1 in the supernatants of cultured cells. Also on K 562 cells stimulated by TNF-alpha, a PMA-induced release of ICAM-1 was observed in addition to the known spontaneous shedding. In contrast to the results with K 562 cells, no PMA-induced shedding of ICAM-1 was found on U 937 cells. This indicates a cell-specific process for K 562 cells. The PMA-mediated release of ICAM-1 from K 562 cells suggests that the shedding process does not only occur in parallel to the surface expression of ICAM-1, but may be controlled by particular mechanisms of down-regulation.
authors.affiliation: Institut für Biochemie, Otto-von-Guericke Universität Magdeburg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Fritz
authors.forename: F
authors.initials: F
authors.lastname: Striggow
authors.forename: D
authors.initials: D
authors.lastname: Reinhold
authors.forename: T
authors.initials: T
authors.lastname: Schlüter
authors.forename: P
authors.initials: P
authors.lastname: Schönfeld
authors.forename: S
authors.initials: S
authors.lastname: Ansorge
authors.forename: R
authors.initials: R
authors.lastname: Bohnensack
mesh_terms: D015153:Blotting, Western; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D019084:Fluorescent Antibody Technique, Indirect; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D004915:Leukemia, Erythroblastic, Acute; D008856:Microscopy, Fluorescence; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1; D013755:Tetradecanoylphorbol Acetate