title: Effects of phosphorothioate anti-sense oligodeoxynucleotides on colorectal cancer cell growth and telomerase activity.
abstract: OBJECTIVE
  To investigate the inhibitory effect of phosphorothioate anti-sense oligodeoxynucleotides (PASODN) on colorectal cancer LS-174T cells in vitro and the mechanism of inhibition of telomerase activity in these cells.
  
  
  METHODS
  PASODN were used to infect LS-174T cells and block human telomerase RNA (hTR) through anti-sense technology. The inhibitory effect of PASODN was evaluated by colony-forming inhibition assay and growth curve. Changes of telomerase activity in LS-174T cells were detected by polymerase chain reaction-enzyme-linked immunosorbent assay (PCR-ELISA), and the level of apoptosis was analyzed by flow cytometry (FCM) assay.
  
  
  RESULTS
  PASODN showed a dose and time-dependent inhibition of cell proliferation. The optimal dosage of PASODN was 10 mumol/L. The colony-forming efficiency was 10.3% in PASODN group after 10 d, whereas that in phosphorothioate mis-sense oligodeoxynucleotides (PMSODN) group with the same concentration and in PBS group (blank control) was 49.1% and 50.7%, respectively. PCR-ELISA results indicated that telomerase activity in the PASODN group was obviously inhibited in comparison with in the control groups (P<0.01, t = 3.317 and 3.241, t0.01(20) = 2.845). Meanwhile, before the number of cells was decreased, the morphological changes were observed in the cells of PASODN group. The cells in PASODN group showed the apoptotic peak at 72 h after infection, whereas the control group did not show.
  
  
  CONCLUSIONS
  Specific sequence oligonucleotides can inhibit telomerase activity and lead to cell apoptosis, suggesting a novel treatment strategy for malignant tumors induced by telomerase.
authors.affiliation: Department of Abdominal Surgery, Tumour Hospital of Harbin Medical University, Harbin 150040, Heilongjiang Province, China. 1966120808@sina.com
authors.forename: Xi-Shan
authors.initials: XS
authors.lastname: Wang
authors.forename: Kuan
authors.initials: K
authors.lastname: Wang
authors.forename: Xue
authors.initials: X
authors.lastname: Li
authors.forename: Song-Bin
authors.initials: SB
authors.lastname: Fu
mesh_terms: D017209:Apoptosis; D002455:Cell Division; D045744:Cell Line, Tumor / Q000166:cytology; D015179:Colorectal Neoplasms; D004789:Enzyme Activation / Q000235:genetics; D005434:Flow Cytometry; D006801:Humans; D014411:Neoplastic Stem Cells; D020319:Oligodeoxyribonucleotides, Antisense / Q000494:pharmacology*; D019098:Telomerase / Q000378:metabolism*; D013873:Thionucleotides / Q000494:pharmacology*
chemical_list: D020319:Oligodeoxyribonucleotides, Antisense; D013873:Thionucleotides; D019098:Telomerase