title: Increased apoptosis in U937 cells over-expressing lipocortin 1 (annexin I).
abstract: The potential involvement of endogenous lipocortin 1 in the process of cellular apoptosis, particularly in cells of the myelo-monocytic lineage, has been investigated. U937 cells were transfected either with an antisense or a sense DNA for lipocortin 1 and the stable clones 36.4AS clone (20-40% lower lipocortin 1 levels) and 15S (30% higher lipocortin 1 levels) were obtained. Cell apoptosis was induced by incubation with tumor necrosis factor-alpha: optimal responses were observed within a 24 h incubation period at a 5 ng/ml concentration. Apoptosis was assessed both morphologically, by annexin V binding and cell cycle analysis with propidium iodide. Whilst no consistent difference was seen between wild type cells and clone 36.4AS, a higher incidence of apoptosis (ranging from +30% to + 60%) was observed in the 15S clone. Release of arachidonic acid from loaded cells was promoted by 24 h incubation with the cytokine, and a higher degree of release was measured in the 15S clone. These data indicate that endogenous intracellular lipocortin 1 is involved in the promotion of apoptosis in cells of the myelo-monocytic derivation.
authors.affiliation: The William Harvey Research Institute, London, UK.
authors.forename: S
authors.initials: S
authors.lastname: Canaider
authors.forename: E
authors.initials: E
authors.lastname: Solito
authors.forename: C
authors.initials: C
authors.lastname: de Coupade
authors.forename: R J
authors.initials: RJ
authors.lastname: Flower
authors.forename: F
authors.initials: F
authors.lastname: Russo-Marie
authors.forename: N J
authors.initials: NJ
authors.lastname: Goulding
authors.forename: M
authors.initials: M
authors.lastname: Perretti
mesh_terms: D017305:Annexin A1 / Q000096:biosynthesis*; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D016718:Arachidonic Acid / Q000378:metabolism; D002453:Cell Cycle / Q000502:physiology; D002999:Clone Cells / Q000187:drug effects / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D010741:Phospholipases A / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D020298:U937 Cells
chemical_list: D017305:Annexin A1; D014409:Tumor Necrosis Factor-alpha; D016718:Arachidonic Acid; D010741:Phospholipases A