title: Differentiation and apoptosis of U-937 leukemia cells by an active compound from Dendrostellera lessertii.
abstract: Regarding the strong differentiation and anti-leukemic activity of Dendrostellera lessertii extract, an active agent with similar capabilities was isolated from the crude extract of the plant leaves. The aim of this study was to determine whether the anti-proliferative effect observed for this compound, is differentiation-dependent among the drug-treated cells, using U937 cells.
  
  
  
  Monocyte differentiation was evaluated by Wright-Giemsa staining, latex particle assay and flow cytometry. Induction of apoptosis was analyzed by Annexin-PI double staining.
  
  
  
  The new compound, at 0.5-2.5 microg/ml inhibited proliferation of U937 cells by more than 70% and their viabilities were decreased by 47 +/- 2.1% after 72 h of treatments. In addition, we found that the effect of the new compound on U937 cells was associated with differentiation toward monocyte/macrophage lineage based on nitroblue tetrazolium reduction assay, morphology change, phagocytic activity and expression of cell surface markers (CD14 and CD11b) as analyzed by flow cytometry. Moreover, our results indicated that the treatment of U937 cells with the new compound for 3 to 4 days induced apoptosis as assayed qualitatively by acridine orange/ethidium bromide and Annexin-V/PI double staining technique using flow cytometry.
  
  
  
  Based on these observations, it is concluded that the anti-proliferative function of the new compound is exerted through differentiation-dependent apoptosis among the treated cells, similar to the function of 3-hydrogenkwadaphnin previously characterized from D. lessertii crude extract.
authors.affiliation: Institute of Biochemistry and Biophysic, University of Tehran, Tehran, Iran.
authors.forename: Azadeh
authors.initials: A
authors.lastname: Meshkini
authors.affiliation: Institute of Biochemistry and Biophysic, University of Tehran, Tehran, Iran.
authors.forename: Razieh
authors.initials: R
authors.lastname: Yazdanparast
authors.affiliation: Dept. of Immunology,  Medical School, P. O. Box 14155-6447, University of Tehran, Tehran, Iran.
authors.forename: Mojgan
authors.initials: M
authors.lastname: Haidari
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D039481:CD11b Antigen / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D006801:Humans; D007938:Leukemia / Q000473:pathology*; D018950:Lipopolysaccharide Receptors / Q000378:metabolism; D013194:Staining and Labeling; D029645:Thymelaeaceae / Q000737:chemistry*; D020298:U937 Cells
chemical_list: D000970:Antineoplastic Agents; D039481:CD11b Antigen; D018950:Lipopolysaccharide Receptors