title: [Cytotoxicity of homoharringtonine on leukemic stem-like cells in AML cell line KG-1].
abstract: OBJECTIVE
  To investigate the effect of homoharringtonine (HHT) on leukemic stem-like cells (LSC) in human acute myeloid leukemia (AML) cell lines.
  
  
  METHODS
  The phenotypes of AML cell lines U937,Kasumi-1,and KG-1 cells were analyzed by flow cytometry (FACS). The effect of HHT on leukemia stem-like cells with immunophenotype of CD34(+)CD38(-)CD96(+) was detected with FACS. Cell growth was measured by MTT assay. Activation of Caspase pathway and expression of apoptosis-related regulator proteins were examined by Western blotting.
  
  
  RESULTS
  FACS demonstrated that the 69% of KG-1 cells expressed LSC phenotype CD34(+)CD38(-)CD96(+), while 26.7% on Kasumi-1 cells expressed this marker. In contrast,U937 cells showed CD96 negative. HHT significantly inhibited cell growth of KG-1 cells with an IC(50) of 16.9 ng/ml at 48 h. The ratio of CD34(+)CD38(-)CD96(+) cells decreased from 63.6% to 17.1% after HHT treatment. Enhanced apoptosis was demonstrated in HHT group evidenced by strong activation of Caspase-9,Caspase-3 and PARP.HHT treatment resulted in down-regulation of expression of anti-apoptotic protein BCL-2 and phosphorylated-Akt.
  
  
  CONCLUSIONS
  HHT can effectively kill the leukemic stem-like cells in human AML cell line KG1 by inhibiting cell growth and inducing apoptosis which is associated with activation of Caspase pathway and down-regulation of anti-apoptotic proteins and phosphorylated-Akt.
authors.affiliation: Department of Hematology, Zhejiang Province Traditional Chinese Medicine Hospital, Hangzhou, China.
authors.forename: Jian-ping
authors.initials: JP
authors.lastname: Shen
authors.forename: Hong
authors.initials: H
authors.lastname: Yang
authors.forename: Wan-mao
authors.initials: WM
authors.lastname: Ni
authors.forename: Wen-bin
authors.initials: WB
authors.lastname: Qian
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic; D006248:Harringtonines / Q000494:pharmacology*; D000077863:Homoharringtonine; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000378:metabolism / Q000473:pathology*; D014411:Neoplastic Stem Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D006248:Harringtonines; D000077863:Homoharringtonine; C505407:CASP3 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053453:Caspase 9