Background: Although intravesical bacillus Calmette-Guerin (BCG) therapy is very effective in the treatment of and prophylaxis against superficial bladder cancer, its exact mechanism of action is not clear. In this study, the effect of BCG on telomerase activity was examined in the T24 and J82 bladder cancer cell lines, the ACHN human renal cell carcinoma cell line, and the PC-3 human prostate cancer cell line.
Methods: T24 and J82 cells were cocultured with BCG for 5 days. Telomerase activity was measured by telomeric repeat amplification protocol. Cell-cycle phase was determined by FACS analysis.
Results: Telomerase activity in all cell lines provided high absorbance. Telomerase activity in BCG-treated T24 and J82 cells was significantly decreased when compared with that in the nontreated cells. On the other hand, telomerase activity did not change in ACHN and PC-3 cells after they had been cocultured with BCG. In BCG-treated T24 cells and J82 cells, apoptotic cells were markedly increased compared with those in the nontreated cells.
Conclusion: These results suggest that the reduction of telomerase activity is related to the mechanism of BCG effects. Possible mechanisms to be considered are either that BCG inhibits telomerase first, or that it induces apoptosis and decreases telomerase activity as a result of this induction.