title: Effect of Ku70 expression on radiosensitivity in renal carcinoma 786-O cells.
abstract: BACKGROUND
  Radiotherapy plays an important role in cancer therapy. However, the radioresistance of some human cancers, particularly renal carcinoma, often results in radiotherapy failure. The Ku protein is essential for the repair of a majority of DNA double-strand breaks in mammalian cells, but effect of Ku70 expression on radiosensitivity in renal carcinoma is unclear. Here, we investigate the impact of Ku70 on radiosensitivity in renal carcinoma cells through regulating the expression of Ku70.
  
  
  METHODS
  The stable overexpression of Ku70 or suppression of Ku70 in renal carcinoma cell line (786-O) was generated by retrovirus-mediated Ku70 cDNA or shRNA targeting Ku70. Ku70 expression was determined by RT-PCR and Western blot analysis, the apoptosis of the stable cells was assayed with flow cytometry and TUNEL assay and the effect of radiation on the livability of stable cells was assessed by MTT assay.
  
  
  RESULTS
  Up-regulation of Ku70 expression of 786-O cells could inhibit cell apoptosis and reduce susceptibility to radiation. On the contrary, 786-O cells with suppression of Ku70 expression could induce cell apoptosis and significantly enhance the sensitivity to radiation.
  
  
  CONCLUSIONS
  These findings indicated that Ku70 might play an important role in radioresistance of renal carcinoma, and inhibition of Ku70 can increase the radiosensitivity of 786-O cells by enhancing apoptosis, suggesting down-regulation of Ku70 expression combined with radiotherapy will be a potential strategy for renal cell carcinoma therapy.
authors.affiliation: National Hepatobiliary and Enteric Surgery Research Center, Centeral South University, Changsha 410008, China.
authors.forename: Defeng
authors.initials: D
authors.lastname: Qi
authors.affiliation: Department of Urology, Minimally Invasive Surgery Center, Guangdong Provincial Key Laboratory of Urology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510230, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Hu
authors.affiliation: National Hepatobiliary and Enteric Surgery Research Center, Centeral South University, Changsha 410008, China.
authors.forename: Yangde
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Urology, Minimally Invasive Surgery Center, Guangdong Provincial Key Laboratory of Urology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510230, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Peng
authors.affiliation: Department of Urology, Minimally Invasive Surgery Center, Guangdong Provincial Key Laboratory of Urology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510230, China.
authors.forename: Weidong
authors.initials: W
authors.lastname: Ji
keywords: Cell apoptosis; Ku70; Radiosensitivity; Renal cell carcinoma