title: [Effects of simvastatin plus all-trans retinoic acid on WT1/hDMP1 gene expression profiles of human promyelocytic leukemia cell line NB4].
abstract: OBJECTIVE
  To investigate the effects of simvastatin (SV) plus all-trans retinoic acid (ATRA) on the proliferation, differentiation, apoptosis and WT1/hDMP1 gene expression profiles of human promyelocytic leukemia cell line NB4.
  
  
  METHODS
  The NB4 cell was incubated with simvastatin and ATRA alone or in combination. And the NB4 cell without any treatment was adopted as a normal control. The cells of different groups were collected at 24, 48 and 72 h post-incubation. Their morphological changes were observed after Wright staining. The method of MTT was employed to assay the growth inhibition rate and flow cytometry was used to detect the early-stage ratios of apoptosis and cell necrosis. Real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) was used to detect the WT1/hDMP1 gene expression levels.
  
  
  RESULTS
  The cell inhibition rates increased gradually (F = 7.15, P = 0.000) at 15, 10 and 5 µmol/L SV respectively. And so did the expression levels of CD11b (F = 3.41, P = 0.014) and Annexin-V (F = 43.38, P = 0.000). However the expression levels of WT1 decreased gradually (F = 5.35, P = 0.001) reversely with the elevated levels of hDMP1 (F = 22.61, P = 0.000). Furthermore the NB4 cell exhibited the most significant changes at 15 µmol/L SV. After a 72-hour incubation, the expression levels of CD11b (89.46% ± 9.13%)and hDMP1 (626.9 ± 56.9) in NB4 cells at 15 µmol/L SV plus 0.5 µmol/L ATRA were significantly higher than those with ATRA(71.27% ± 7.27%, P = 0.000 and 421.8 ± 38.3, P = 0.003 in each) and SV alone(62.41% ± 6.37%, P = 0.003 and 241.4 ± 21.9, P = 0.003 in each). A combination of 15 µmol/L SV with 0.5 µmol/L ATRA displayed obvious interactions with the expressions of CD11b and hDMP1 (F = 4.09, P = 0.025 and F = 29.58, P = 0.000 in each). And there was no significant interaction for cell inhibition rates and Annexin-V expression.
  
  
  CONCLUSIONS
  Simvastatin in vitro inhibits the proliferation of NB4 cell, induces its differentiation and promotes its apoptosis. And the lowered expression of WT1 has a dose-dependent correlation with the elevated expression of hDMP1. It indicates that simvastatin has the synergistic in vitro anti-promyelocytic potency.
authors.affiliation: Department of Hematology, First People's Hospital, Changzhou, China.
authors.forename: Ting-xiu
authors.initials: TX
authors.lastname: Jiang
authors.forename: Wei-ying
authors.initials: WY
authors.lastname: Gu
authors.forename: Guo-qiang
authors.initials: GQ
authors.lastname: Qiu
authors.forename: Zi-xing
authors.initials: ZX
authors.lastname: Chen
authors.forename: Zhi-lin
authors.initials: ZL
authors.lastname: Wang
authors.forename: Hao-qing
authors.initials: HQ
authors.lastname: Wu
authors.forename: Xiao-ying
authors.initials: XY
authors.lastname: Hua
authors.forename: Bai
authors.initials: B
authors.lastname: He
authors.forename: Wei
authors.initials: W
authors.lastname: Wu
authors.forename: Xiao-bao
authors.initials: XB
authors.lastname: Xie
authors.forename: Xiang-shan
authors.initials: XS
authors.lastname: Cao
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D016326:Extracellular Matrix Proteins / Q000235:genetics*; D020869:Gene Expression Profiling; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D010750:Phosphoproteins / Q000235:genetics*; D019821:Simvastatin / Q000494:pharmacology*; D014212:Tretinoin / Q000494:pharmacology*; D025721:WT1 Proteins / Q000235:genetics*
chemical_list: C513309:DMP1 protein, human; D016326:Extracellular Matrix Proteins; D010750:Phosphoproteins; D025721:WT1 Proteins; D014212:Tretinoin; D019821:Simvastatin