Small interfering RNA against the apurinic or apyrimidinic endonuclease enhances the sensitivity of human pancreatic cancer cells to gemcitabine in vitro.
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.
Xiong
Guang Su
GS
Department of Gastroenterology, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai Institute of Digestive Disease, Shanghai, China.
Sun
Hui Ling
HL
Wu
Shu Ming
SM
Mo
Jian Zhong
JZ
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
D000964:Antimetabolites, Antineoplastic; D034741:RNA, Small Interfering; D003841:Deoxycytidine; C085108:APEX1 protein, human; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D000093542:Gemcitabine