title: Nitric oxide-donating acetylsalicylic acid induces apoptosis in chronic lymphocytic leukemia cells and shows strong antitumor efficacy in vivo.
abstract: OBJECTIVE
  Nitric oxide-donating acetylsalicylic acid (NO-ASA) has been shown to possess an antineoplastic effect in Wnt-/β-catenin-active cancers. As chronic lymphocytic leukemia (CLL) cells exhibit aberrantly active Wnt signaling, we investigated the effect of the para-isomer of NO-ASA on CLL cell survival in vitro and in a CLL-like xenograft mouse model.
  
  
  METHODS
  Apoptosis in primary CLL cells was determined by flow cytometric annexin V-FITC (fluorescein isothiocyanate)/PI (propidium iodide) staining and immunoblotting of caspases, poly(ADP-ribose) polymerase (PARP), and antiapoptotic proteins. Interference of NO-ASA with Wnt/β-catenin signaling was analyzed through immunoblots of different pathway members. Influence of caspase activation was investigated by pretreatment with a pan-caspase inhibitor. CLL-like JVM3 cells were subcutaneously inoculated into irradiated nude mice that were treated with 100 mg of para-NO-ASA/kg of body weight p.o. (by mouth) for 21 days.
  
  
  RESULTS
  para-NO-ASA induced apoptosis in CLL cells with an LC(50) (lethal concentration) of 8.72 + 0.04 μmol/L, whereas healthy blood cells were not affected. Furthermore, the compound induced caspase 9, caspase 3, and PARP cleavage. In addition, cleavage of β-catenin and downregulation of β-catenin/lymphoid enhancer factor (Lef)-1 targets was observed. para-NO-ASA demonstrated strong antitumor efficacy in the xenograft mouse model with a tumor inhibtion rate of 83.4%. During therapy, no gross toxicity could be observed.
  
  
  CONCLUSIONS
  para-NO-ASA selectively induces apoptosis in primary CLL cells and efficiently reduces tumor growth in a CLL-like xenograft model. As NO-ASA is orally available and is generally well tolerated, para-NO-ASA might be a promising new compound for CLL therapy.
authors.affiliation: Department I of Internal Medicine, Center for Integrated Oncology, University at Cologne, Cologne, Germany.
authors.forename: Regina
authors.initials: R
authors.lastname: Razavi
authors.forename: Iris
authors.initials: I
authors.lastname: Gehrke
authors.forename: Rajesh Kumar
authors.initials: RK
authors.lastname: Gandhirajan
authors.forename: Simon Jonas
authors.initials: SJ
authors.lastname: Poll-Wolbeck
authors.forename: Michael
authors.initials: M
authors.lastname: Hallek
authors.forename: Karl-Anton
authors.initials: KA
authors.lastname: Kreuzer
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects; D001241:Aspirin / Q000627:therapeutic use*; D020169:Caspases / Q000096:biosynthesis; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000188:drug therapy*; D051821:Lymphoid Enhancer-Binding Factor 1 / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D020030:Nitric Oxide Donors / Q000627:therapeutic use*; D023041:Xenograft Model Antitumor Assays; D051176:beta Catenin / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; C497573:LEF1 protein, human; D051821:Lymphoid Enhancer-Binding Factor 1; D020030:Nitric Oxide Donors; D051176:beta Catenin; D020169:Caspases; D001241:Aspirin