Background & objective: Inhibition of telomere length can be achieved through suppression of telomerase activity, which may result in the inhibition of immortal cell proliferation. In order to explore the possibility of the telomerase as a target for lung cancer therapy, we investigated the effects of anti-sense human telomerase reverse transcriptase (hTERT) on telomerase activity and cell proliferation of A549 lung cancer cell line.
Methods: The anti-sense hTERT cDNA, an 835 bp in the 5' region of hTERT mRNA was amplified by reverse transcription polymerase chain reaction (RT-PCR), before cloning into pLXSN retroviral vector in sense and anti-sense orientations. A549 cells, a human lung cancer cell line, were infected with recombinant virus obtained after transfection into packaging cell PT67. The expression of hTERT protein was determined by Western blot analysis. The telomerase activity was measured by telomerase repeat amplification protocol (TRAP). The cell proliferation was depicted by cell morphology under inverted microscopy as well as cell growth curve. Apoptosis was analyzed by flow cytometry and DNA electrophoresis.
Results: Compared with sense hTERT transduction, hTERT expression and telomerase activity significantly decreased in A549 cells after anti-sense hTERT transduction. The cell proliferation was markedly inhibited with evidence of apoptosis.
Conclusion: Anti-sense hTERT exhibited significant inhibition of telomerase activity and cell proliferation, in addition to acceleration of apoptosis. This implied the possibility of hTERT as the potential target for gene therapy of lung cancer.