Efficient inhibition of human telomerase activity by antisense oligonucleotides sensitizes cancer cells to radiotherapy.
OBJECTIVE
To investigate the effect of the antisense oligonucleotides (ASODN) specific for human telomerase RNA (hTR) on radio sensitization and proliferation inhibition in human neurogliocytoma cells (U251).


METHODS
U251 cells were transfected with hTR ASODN or nonspecific oligonucleotides (NSODN). Before and after irradiation of (60)Co- gamma ray, telomerase activity was assayed by telomeric repeat amplification protocol ( TRAP-PCR-ELISA), and DNA damage and repair were examined by the comet assay. The classical colony assay was used to plot the cell-survival curve, to detect the D(0 )value.


RESULTS
hTR antisense oligonucleotides could downregulate the telomerase activity, increase radiation induced DNA damage and reduce the subsequent repair. Furthermore, it could inhibit the proliferation and decrease the D(0 ) value which demonstrates rising radiosensitivity. However, telomere length was unchanged over a short period of time.


CONCLUSIONS
These findings suggest that an ASODN-based strategy may be used to develop telomerase inhibitors, which can efficiently sensitize radiotherapy.
Ji
Xue-mei
XM
Department of Chemotherapy and Radiation Oncology, Zhongnan Hospital, Wuhan University, Wuhan 430071, China.
Xie
Cong-hua
CH
Fang
Ming-hao
MH
Zhou
Fu-xiang
FX
Zhang
Wen-jie
WJ
Zhang
Ming-sheng
MS
Zhou
Yun-feng
YF
D045744:Cell Line, Tumor; D049109:Cell Proliferation; D003037:Cobalt Radioisotopes; D004249:DNA Damage; D004260:DNA Repair; D005720:Gamma Rays; D005910:Glioma / Q000201:enzymology* / Q000473:pathology; D006801:Humans; D016376:Oligonucleotides, Antisense / Q000235:genetics / Q000494:pharmacology*; D011836:Radiation Tolerance; D019098:Telomerase / Q000235:genetics / Q000378:metabolism*; D016615:Telomere / Q000187:drug effects; D014162:Transfection
D003037:Cobalt Radioisotopes; D016376:Oligonucleotides, Antisense; D019098:Telomerase