[Effect of tankyrase antisense oligonucleotide combined human telomerase reverse transcriptase antisense oligonucleotide on telomere dynamics in human lung adenocarcinoma A549 cells]

Tankyrase (TANKS) regulates telomerase-mediated telomere elongation and plays an important role in cellular senescence and immortalization. This study was to determine the effect of tankyrase antisense oligonucleotide (asTANKS) combined human telomerase reverse transcriptase antisense oligonucleotide (ashTERT) on telomere dynamics in human lung adenocarcinoma A549 cells.

A549 cells were transfected with ashTERT, asTANKS, ashTERT combined asTANKS, and human telomerase reverse transcriptase sense oligonucleotide (shTERT), tankyrase sense oligonucleotide (sTANKS), or blank vector as control. The expression of hTERT mRNA was detected by reverse transcription-polymerase chain reaction (RT-PCR). Telomerase activity was detected by enzyme-linked immunosorbent assay-PCR (ELISA-PCR). Tankyrase activity was detected by Western blot. Telomere length was analyzed by quantitative fluorescence in situ hybridization (Q-FISH). Cell proliferation was measured by population doubling test.

The mRNA level and telomerase activity of hTERT in A549 cells were strongly suppressed by ashTERT, but not by asTANKS; while tankyrase activity was significantly inhibited by asTANKS, not by ashTERT. Telomere length was significantly shorter in the cells treated with ashTERT combined asTANKS than in the cells treated with either ashTERT or asTANKS [(3.55+/-0.08) kb vs. (7.59+/-0.07) kb and (7.33+/-0.09) kb, t = 37.33, t = 32.50, P < 0.001]. The generational activity of the A549 cells continuously treated with ashTERT combined asTANKS was significantly weaker than those treated with either ashTERT or asTANKS [(24.53+/-0.40) population double times (PD) vs. (56.92+/-0.46) PD and (53.33+/-0.57) PD, t = 53.38, t = 43.39, P < 0.001].

The combination of ashTERT and asTANKS can enhance the efficacy of telomere shortening and hasten early tumor cellular crisis. Tankyrase might be a potential target of telomere-based molecular cancer therapy.