title: Small interfering RNA against the apurinic or apyrimidinic endonuclease enhances the sensitivity of human pancreatic cancer cells to gemcitabine in vitro.
abstract: OBJECTIVE
  To investigate whether the downregulation of human apurinic or apyrimidinic endonuclease/redox factor-1 gene (APE1/Ref-1) expression by ribonucleic acid interference (RNAi) would increase the sensitivity of SW1990 cells to gemcitabine.
  
  
  METHODS
  Chemically synthesized small interfering RNA (siRNA) directed against human APE1/Ref-1 (si-APE1) was transfected into SW1990 cells through transfection reagents. The mRNA expression of APE1/Ref-1 was detected by semi-quantitative RT-PCR and the protein expression of APE1/Ref-1 was detected by Western blot; cell proliferation and apoptosis were studied by a Cell Counting Kit 8 (CCK-8) and flow cytometry (FCM) and fluorescence microscopy.
  
  
  RESULTS
  After transfecting the SW1990 cells with siRNA directed against human APE1/Ref-1, the mRNA expression of APE1/Ref-1 of these cells was reduced, and its protein expression was reduced by 55.41 +/- 3.58%. The CCK-8 assay showed that the absorbance and the inhibition of cell growth transfected with si-APE1 were significantly different from the blank (cultured with Dulbecco's modified Eagle's medium) and negative control (given 50 nmol/L scrambled control siRNA). The inhibition rates of cell growth of the si-APE1 group at 24, 48, 72 h were 41.69 +/- 2.78%, 24.83 +/- 3.70% and 21.27 +/- 9.82%, respectively. A FCM analysis and cell morphology study showed that the apoptotic rate of SW1990 cells transfected with si-APE1 combined with gemcitabine treatment was significantly different from the blank control and others.
  
  
  CONCLUSIONS
  To knock down APE1/Ref-1 gene expression may significantly sensitize the SW1990 cells to gemcitabine and enhance cell apoptosis.
authors.affiliation: Department of Gastroenterology, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai Institute of Digestive Disease, Shanghai, China.
authors.forename: Guang Su
authors.initials: GS
authors.lastname: Xiong
authors.forename: Hui Ling
authors.initials: HL
authors.lastname: Sun
authors.forename: Shu Ming
authors.initials: SM
authors.lastname: Wu
authors.forename: Jian Zhong
authors.initials: JZ
authors.lastname: Mo
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use*; D017209:Apoptosis; D045744:Cell Line, Tumor; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000235:genetics* / Q000378:metabolism; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D015536:Down-Regulation; D006801:Humans; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics*; D000093542:Gemcitabine
chemical_list: D000964:Antimetabolites, Antineoplastic; D034741:RNA, Small Interfering; D003841:Deoxycytidine; C085108:APEX1 protein, human; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D000093542:Gemcitabine