title: [Inhibitory effects of rapamycin on proliferation of chronic myelogenous leukemia cells and its mechanism].
abstract: OBJECTIVE
  To explore the inhibitory effects of rapamycin on proliferation of chronic myelogenous leukemia (CML) cells and its possible mechanism.
  
  
  METHODS
  The effects of rapamycin at various concentrations on cell proliferation of CML cell line K562 cells were analyzed by MTT. The expressions of mTOR, 4E-BP1 and p70S6K at protein and mRNA level in K562 cells with rapamycin treatment were detected by Western blot and RT-PCR. The protein expressions and phosphorylation of mTOR, 4E-BP1 and p70S6K in primary bone marrow cells from CML patients at chronic phase (CP) were also investigated by Western blot, bone marrow cells from healthy people were used as control. Data were analyzed by the χ(2) test, Fisher's exact test and one-way analysis of variance (ANOVA).
  
  
  RESULTS
  The phosphorylation of mTOR, 4E-BP1 and p70S6K were significantly increased in CML bone marrow cells compared with that of normal control (70.6% vs 30.0%, 76.5% vs 40.0%, 73.5% vs 20.0%, respectively, P < 0.05). The proliferation of K562 cells was significantly inhibited with 20 nmol/L and more rapamycin treatment. The phosphorylation of mTOR was decreased after rapamycin treatment, as well as the expressions of 4E-BP1 and p70S6K at protein and mRNA level (P < 0.05).
  
  
  CONCLUSIONS
  mTOR signaling played an important role in CML pathogenesis, and rapamycin could decrease CML cells proliferation by inhibiting the activity of mTOR signaling in vitro.
authors: Department of Hematology, the Second Hospital of Hebei Medical University, Shijiazhuang, China.
authors: Jie
authors: J
authors: Li
authors: Li-ying
authors: LY
authors: Xue
authors: Yu-xiang
authors: YX
authors: Han
authors: Yin-tao
authors: YT
authors: Shang
authors: Li
authors: L
authors: Yao
authors: Jian-min
authors: JM
authors: Luo
mesh_terms: D016022:Case-Control Studies; D049109:Cell Proliferation / Q000187:drug effects*; D006801:Humans; D020014:K562 Cells; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000378:metabolism / Q000473:pathology*; D010766:Phosphorylation / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects; D020123:Sirolimus / Q000494:pharmacology*; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism
chemical_list: C546842:MTOR protein, human; D058570:TOR Serine-Threonine Kinases; D020123:Sirolimus