title: [Effect of NOR1 gene knockdown on the biological behavior of HeLa cells].
abstract: OBJECTIVE
  To explore the effect of the oxidored nitro domain containing protein 1 (NOR1) gene knockdown on the biological behavior of HeLa cells in cervical carcinoma.
  
  
  METHODS
  The recombinant plasmids pSUPER-shNOR1-1, pSUPER-shNOR1-2 and pSUPERscramble, which targeted to NOR1 gene, were constructed by pSUPER.neo+GFP vector, transfected into HeLa cells respectively using Lipofectamine 2000 reagent, and followed by G418 selection. The expression level of NOR1 mRNA and protein were determined by RT-PCR and Western blotting, respectively. Methyl thiazolyl tetrazolium (MTT) assay was performed to determine the growth curve of cell viability. The stable transfectants were treated with H₂O₂ and cell apoptosis was determined by Hoechst 33258 staining and terminal deoxynucleotidyl transferasemediated dUTP nick end labeling (TUNEL) assay. The expression levels of Bcl-2, cleaved caspase 9 and poly ADP-ribose polymerase (PARP) were measured by Western blot.
  
  
  RESULTS
  NOR1- knockdown HeLa cells were successfully constructed by transfection of pSUPER-shNOR1-1 or pSUPER-shNOR1-2 plasmids into HeLa cells. MTT assay showed that the silence of endogenous NOR1 in HeLa cells could lead to the increase in cell viability and proliferation, and the inhibition of H₂O₂-induced apoptosis compared with the negative control. Western blot showed that the expression level of active caspase 9 and cleaved PARP was inhibited in NOR1-knockdown cells when they were treated with H₂O₂ while the expression level of Bcl-2 protein increased.
  
  
  CONCLUSIONS
  Silence of endogenous NOR1 facilitates the cell viability and growth of HeLa cells, and attenuates HeLa cells apoptosis induced by H₂O₂, which might be mediated by up-regulation of Bcl-2 level and down-regulation of the cleaved caspase 9 cascade.
authors.affiliation: Department of Dermatology, Second Xiangya Hospital, Central South University, Changsha 410011, China.
authors.forename: Yixin
authors.initials: Y
authors.lastname: Tan
authors.forename: Wenjuan
authors.initials: W
authors.lastname: Li
authors.forename: Mei
authors.initials: M
authors.lastname: Yi
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Pan
authors.initials: P
authors.lastname: Zheng
authors.forename: Haijing
authors.initials: H
authors.lastname: Zhang
authors.forename: Bo
authors.initials: B
authors.lastname: Xiang
authors.forename: Guiyuan
authors.initials: G
authors.lastname: Li
mesh_terms: D017209:Apoptosis; D053453:Caspase 9 / Q000378:metabolism; D002470:Cell Survival; D015536:Down-Regulation; D055785:Gene Knockdown Techniques; D005822:Genetic Vectors; D006367:HeLa Cells; D006801:Humans; D006861:Hydrogen Peroxide; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D012333:RNA, Messenger; D014162:Transfection; D015854:Up-Regulation
chemical_list: C000595707:BCL2 protein, human; D026901:Membrane Transport Proteins; C479458:OSCP1 protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D006861:Hydrogen Peroxide; C506433:CASP9 protein, human; D053453:Caspase 9