title: [Influence of I2PP2A gene silencing by RNA interference on proliferation and apoptosis of human acute promyelocytic leukemia cell line NB4-R1].
abstract: OBJECTIVE
  To explore the effect of RNA interference of human I2PP2A gene on the proliferation and apoptosis of retinoic acid-resistant human acute promyelocytic leukemia (APL) cell line NB4-R1.
  
  
  METHODS
  Designed and constructed a RNA interference lentiviral vector I2PP2A-shRNA which targeted against I2PP2A gene, then transfected it into NB4-R1 via polybrene mediation. The I2PP2A expression levels before and after transfection were detected by qRT-PCR and Western blot, respectively. Meanwhile, the proliferation and apoptosis rates of each group were determined by CCK-8 and flow cytometry assay. The protein expressions of caspase-8 and PARP were detected by Western blot.
  
  
  RESULTS
  Both qRT-PCR and Western blot data showed the I2PP2A expression level was significantly downregulated in the transfection group. The I2PP2A mRNA expression level decreased by (70.0 ± 9.6)% and (64.0 ± 6.2)% respectively, compared with blank control and negative control group, and the I2PP2A protein expression level showed a consistent trend. CCK-8 proliferation assay indicated the NB4-R1 cell proliferation rate in I2PP2A-shRNA transfection group significantly reduced compared to blank control group (P<0.05). Flow cytometry results showed that NB4-R1 apoptosis rate in I2PP2A-shRNA transfection group increased by (6.30 ± 0.67) times and (6.04 ± 0.56) times, respectively (P<0.01). After inhibition of I2PP2A, the total caspase-8 and total PARP expressions decreased by (44.0 ± 3.1)% and (57.0 ± 4.0)%, respectively; Meanwhile, the cleaved caspase-8 (p43) and cleaved PARP (p89) increased by (36.0 ± 2.5)% and (45.0 ± 4.8)%, respectively compared with blank control group (P<0.05).
  
  
  CONCLUSIONS
  I2PP2A gene silenced by RNA interference could inhibit the proliferation and promote the apoptosis of NB4-R1, which may be regulated through caspase-8-induced exogenous apoptosis pathway.
authors.affiliation: Department of Hematology, The First Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an 710061, China.
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Hematology, The First Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an 710061, China.
authors.forename: Pengcheng
authors.initials: P
authors.lastname: He
authors.affiliation: Department of Hematology, The First Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an 710061, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.affiliation: Department of Hematology, The First Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an 710061, China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Cheng
authors.affiliation: Department of Hematology, The First Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an 710061, China.
authors.forename: Mei
authors.initials: M
authors.lastname: Zhang
mesh_terms: D017209:Apoptosis / Q000235:genetics; D053181:Caspase 8 / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000235:genetics; D004268:DNA-Binding Proteins; D019008:Drug Resistance, Neoplasm; D056488:Histone Chaperones / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute / Q000378:metabolism / Q000473:pathology*; D034622:RNA Interference; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014212:Tretinoin / Q000494:pharmacology
chemical_list: D004268:DNA-Binding Proteins; D056488:Histone Chaperones; C513473:SET protein, human; D014157:Transcription Factors; D014212:Tretinoin; C505530:CASP8 protein, human; D053181:Caspase 8