Efficient inhibition of human telomerase activity by antisense oligonucleotides sensitizes cancer cells to radiotherapy
Abstract
Aim: 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 60Co-γ 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 D0 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 D0 value which demonstrates rising radiosensitivity. However, telomere length was unchanged over a short period of time.
Conclusion: These findings suggest that an ASODN-based strategy may be used to develop telomerase inhibitors, which can efficiently sensitize radiotherapy.
Keywords:
Methods: U251 cells were transfected with hTR ASODN or nonspecific oligonucleotides (NSODN). Before and after irradiation of 60Co-γ 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 D0 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 D0 value which demonstrates rising radiosensitivity. However, telomere length was unchanged over a short period of time.
Conclusion: These findings suggest that an ASODN-based strategy may be used to develop telomerase inhibitors, which can efficiently sensitize radiotherapy.