Telomerase assay as a possible predictor of the response to anticancer chemotherapy

Background: The correlation between telomerase activity and antitumor effec ts was investigated in cell lines of human gastric (MKN-28, MKN-45, and MKN -74) and breast (T-47D, MCF-7, ZR75-1) cancers to evaluate the possibility of utilizing this enzyme to predict tumor response to chemotherapy. Materia ls and Methods: After culture with various concentrations of 5-fluorouracil (5-FU) or doxorubicin (DOX) for 3 days, cell viability (trypan blue exclus ion), cell cycle distribution (flow cytometry), and telomerase (TRAP-EZE) w ere measured. Results: Telomerase activity correlated significantly, with t he number of viable cells. After drug exposure, this activity decreased rap idly in a dose-dependent fashion in most cell lines. There was no correlati on between telomerase activity and the distribution of cells in the cell cy cle. Conclusions: As the assay for telomerase activity is extremely sensiti ve and is virtually specific to cancer cells, this method may prove useful for the sensitivity testing of small specimens of human rumors.