title: [An experimental study of telomerase reverse transcriptase (hTERT) DNAzyme on growth of A549/DDP cells].
abstract: BACKGROUND
  Telomerase expresses in many cancers and may contribute to drug-resistance. The aim of this study is to observe the effect of telomerase reverse transcriptase (hTERT) DNAzyme on growth of A549/DDP cells and to explore the possibility of telomerase as a new target in treatment of drug resistance for lung cancer.
  
  
  METHODS
  An hTERT DNAzyme was composed. Telomerase activity was measured by telomeric repeat amplification protocol (TRAP) modified from Kim's method. MTT was used to show the influence of hTERT DNAzyme and cisplatin on A549/DDP cells.
  
  
  RESULTS
  The telomerase activity of A549/DDP cells was down-regulated by hTERT DNAzyme in a dose-dependent manner. The growth inhibition rate of A549/DDP cells was 32.9% by hTERT DNAzyme of 0.25μmol/L, and 60.5% by hTERT DNAzyme combined with 3mg/L cisplatin. The CDI of hTERT DNAzyme and cisplatin was 0.9.
  
  
  CONCLUSIONS
  hTERT DNAzyme can inhibit the growth of A549/DDP cells and has a synergistic effect with cisplatin. It is suggested that telomerase may be a new target in treatment of drug-resistant lung cancer cells.
authors.affiliation: Department of Respiratory Medicine, Chinese PLA General Hospital, Beijing 100853, P.R.China.
authors.forename: Bingxiang
authors.initials: B
authors.lastname: Yu
authors.forename: Jie
authors.initials: J
authors.lastname: Zhu
authors.forename: Youning
authors.initials: Y
authors.lastname: Liu
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Zheng