title: Chemotherapy increases transgene expression in leukemic cells.
abstract: BACKGROUND
  Patients with acute myeloid leukemia (AML) often obtain complete remission with chemotherapy but the majority of patients relapse. Combining chemotherapy and gene therapy appears to be a promising approach; however, the effects of chemotherapy on transgene expression in leukemic cells have not yet been investigated.
  
  
  METHODS
  DA1-3b leukemic cells were transfected with pCDNA3 plasmids carrying GM-CSF or LacZ cDNA. The leukemic K562 cell line and primary cultured AML cells were transduced with an Ad5.CMV-LacZ adenoviral vector. Cells were then incubated with various concentrations of daunorubicin (DNR) and cytosine arabinoside (Ara-C), and expression of the transgene was measured. Murine DA1-3b-pCDNA3/LacZ leukemic cells were also injected into syngeneic C3H/Hej mice.
  
  
  RESULTS
  In the cells carrying pCDNA3, DNR and Ara-C dramatically increased expression of the LacZ and GM-CSF transgenes. Over-expression depended on drug dose and was due to increased transcription. Enhancement was also observed in K562 cells and in some primary cultured AML samples transduced with the Ad5.CMV-LacZ adenovirus. Addition of N-acetyl-L-cysteine inhibited the over-expression, suggesting that reactive oxygen species were involved in activating the CMV promoter. In the A549 lung carcinoma cell line transduced with Ad5.CMV-LacZ, Ara-C had only a minor effect, and DNR had a detrimental effect, suggesting that expression depends on cell type. In vivo experiments in which mice received DA1-3b-pCDNA3/LacZ leukemic cells, and were then treated with Ara-C, also showed increased transgene expression in these leukemic cells.
  
  
  CONCLUSIONS
  In leukemic cells, chemotherapeutic agents can induce over-expression of transgenes. This suggests a promising combined strategy for the treatment of acute leukemia.
authors.affiliation: Unité INSERM 524, Institut de Médecine Prédictive et de Recherche Thérapeutique, Lille (IFR-114), France.
authors.forename: Rodolphe
authors.initials: R
authors.lastname: Vereecque
authors.affiliation: Unité INSERM 524, Institut de Médecine Prédictive et de Recherche Thérapeutique, Lille (IFR-114), France.
authors.forename: Aurore
authors.initials: A
authors.lastname: Saudemont
authors.affiliation: Unité INSERM 524, Institut de Médecine Prédictive et de Recherche Thérapeutique, Lille (IFR-114), France.|Service des Maladies du Sang, Centre Hospitalier et Universitaire, Lille, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Depil
authors.affiliation: Unité INSERM 524, Institut de Médecine Prédictive et de Recherche Thérapeutique, Lille (IFR-114), France.|Service des Maladies du Sang, Centre Hospitalier et Universitaire, Lille, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Quesnel
mesh_terms: D000208:Acute Disease; D000818:Animals; D003561:Cytarabine / Q000494:pharmacology*; D003630:Daunorubicin / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D015870:Gene Expression; D015316:Genetic Therapy; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000235:genetics*; D006801:Humans; D007763:Lac Operon; D007951:Leukemia, Myeloid / Q000188:drug therapy* / Q000235:genetics*; D051379:Mice; D009368:Neoplasm Transplantation; D014162:Transfection; D019076:Transgenes; D014407:Tumor Cells, Cultured
chemical_list: D003561:Cytarabine; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D003630:Daunorubicin