title: [Effect of up-regulated expression of tumor suppressor gene p14(ARF) on apoptosis of chronic myeloid leukemia cells].
abstract: OBJECTIVE
  To investigate the effect of up-regulated expression of tumor suppressor gene p14(ARF) on apoptosis of chronic myeloid leukemia (CML) cells and its interaction with imatinib.
  
  
  METHODS
  Tumor suppressor gene p14(ARF) was transduced into K562 (K562-p14(ARF)) and 4 blast crisis primary CML cells (CML-BC 1-4) using vesicular stomatitis virus glycoprotein (VSV-G) pseudotyped lentiviral vector with cells transduced by empty vector as control. Fluorescence microscopy and flow cytometry were applied to measure transduction efficiency, and Western blotting assay was used to detect p14(ARF) protein of K562 cells. WST-8 method was used to determine cell growth inhibition rate of K562 cells transduced by the target gene under different concentrations of imatinib (0, 0.015, 0.062, 0.125, 0.25, 0.5, 1.0, 2.0 μmol/L). Cell apoptosis and leukemic cellular colony-forming ability were detected by Annexin V-FITC/PI dyeing using flow cytometry (FCM) and semi-solid culture method respectively.
  
  
  RESULTS
  Fluorescence microscopy and FCM showed that transduction efficiency (GFP positive cells) of K562-p14(ARF), K562-VSV and CML-BC1 cells were close to 100%, and CML-BC 2-4 cells were 80% to 90% on average. Results of Western blotting showed that the levels of ARF protein expression of K562 cells transduced by p14(ARF) were significantly higher than of untransduced cells; the apoptosis rate of K562-p14(ARF) was 20%; the mean apoptosis rate of 4 primary leukemic cells transduced by the p14(ARF) [(71.1±22.4)%] was significantly higher than of control group [(12.4±6.2)%] (P<0.05). Imatinib significantly inhibited the proliferation of K562-p14(ARF) cells in a dose-dependent manner. The mean leukemic cellular colony-forming unit of 4 primary leukemic cells transduced by the p14(ARF) (41.5±13.2) was significantly lower than of the control group (88.5±7.9) (P<0.05).
  
  
  CONCLUSIONS
  Increased p14(ARF) gene expression could induce apoptosis of CML cells; Moreover, it could enhance inhibitory effect on cell proliferation when combined with imatinib.
authors.affiliation: Department of Hematology/Oncology,China-Japan Union Hospital of Jilin University, Changchun 130031, China.
authors.forename: Yuan-song
authors.initials: YS
authors.lastname: Bai
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.forename: Xiao-hui
authors.initials: XH
authors.lastname: Liu
authors.forename: En-yong
authors.initials: EY
authors.lastname: Dai
authors.forename: Bu-tong
authors.initials: BT
authors.lastname: Sun
authors.forename: Zhen-xia
authors.initials: ZX
authors.lastname: Lu
mesh_terms: D017209:Apoptosis; D015973:Gene Expression Regulation, Leukemic; D005822:Genetic Vectors; D006801:Humans; D020014:K562 Cells; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000378:metabolism* / Q000473:pathology*; D025803:Tumor Suppressor Protein p14ARF / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D025803:Tumor Suppressor Protein p14ARF