title: [Effects of HO-1 gene expression on proliferation of imatinib resistant CML cells].
abstract: OBJECTIVE
  To investigate the effect of heme oxygenase-1 (HO-1) expression on cell growth and apoptosis in imatinib resistant chronic myeloid leukemia (CML) cells (K562/A02-IM), and explore the relationship between HO-1 gene and CML.
  
  
  METHODS
  The expression of HO-1 in 20 drug-resistant CML patients was detected by RT-PCR. Different concentrations of hemin were used to induce HO-1 expression of K562/A02-IM, HO-1 expression at different time was detected by RT-PCR and Western blot analysis. Cell apoptosis was detected by Annexin V/PI staining, and MTT assay was used to detect viability of K562/A02-IM cells after induction or inhibition of HO-1 gene by hemin and zinc protoporphyrin (ZPP).
  
  
  RESULTS
  RT-PCR showed that HO-1 was expressed in the bone marrow mononuclear cells (BMMNCs). When treated with hemin at different concentrations (0, 10, 20, 40 µmol/L) for 16 h, the expression of HO-1 in K562/A02-IM was increased in a dose-dependent manner, and peaked at 20 µmol/L of hemin for 16 h. The apoptosis rates were (17.61 ± 0.01)%, (12.13 ± 0.11)%, (7.94 ± 0.03)% and (4.62 ± 0.15)% at 0,10, 20 and 40 µmol/L of hemin respectively for 16 h and were (14.7 ± 0.05)%, (8.1 ± 0.07)% and (16.3 ± 0.13)% at 20 µmol/L of hemin treatment for 8,16, and 24 h respectively. Hemin induced apoptosis of K562/A02-IM cells in a dose-dependent manner. The expression of HO-1 was induced in K562/A02-IM cells in a dose-dependent manner, and the survival of K562/A02-IM cells was significantly increased as compared to that of control group. When HO-1 was inhibited by ZPP, the cells survival was sharply decreased compared to that of the control group (P < 0.05).
  
  
  CONCLUSIONS
  HO-1 was expressed in the BMMNCs. It is a kind of molecules whose expression can be induced and can promote the growth of drug-resistant cells. Inhibition of HO-1 expression probably be used for the treatment of drug-resistant CML.
authors.affiliation: Department of Hematology, Affiliated Hospital of Gui Yang Medical College, Guiyang 550004, China.
authors.forename: Ji-Shi
authors.initials: JS
authors.lastname: Wang
authors.forename: Bai-Sheng
authors.initials: BS
authors.lastname: Chai
authors.forename: Qin
authors.initials: Q
authors.lastname: Fang
authors.forename: Ying-Ying
authors.initials: YY
authors.lastname: He
authors.forename: Cheng
authors.initials: C
authors.lastname: Chen
authors.forename: Chang
authors.initials: C
authors.lastname: Yang
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D001549:Benzamides; D002453:Cell Cycle; D049109:Cell Proliferation / Q000187:drug effects; D019008:Drug Resistance, Neoplasm / Q000187:drug effects / Q000235:genetics*; D051547:Heme Oxygenase-1 / Q000235:genetics*; D006801:Humans; D000068877:Imatinib Mesylate; D020014:K562 Cells; D010879:Piperazines / Q000494:pharmacology*; D011743:Pyrimidines / Q000494:pharmacology*
chemical_list: D000970:Antineoplastic Agents; D001549:Benzamides; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate; C496541:HMOX1 protein, human; D051547:Heme Oxygenase-1