Real-time quantitative telomeric repeat amplification protocol assay for the detection of telomerase activity.
BACKGROUND
Telomerase is a ribonucleoprotein enzyme associated with immortalization and transformation of human cells. The telomeric repeat amplification protocol (TRAP) is widely used for the detection of telomerase activity. The TRAP method, although highly sensitive and specific because it includes PCR amplification, is laborious and does not provide precise quantitative information.


METHODS
We developed a real-time quantitative TRAP (RTQ-TRAP) system by combining a real-time PCR technique with the conventional TRAP method. Telomerase activity in human tumor cell lines and in 13 lymphoma samples was measured using the RTQ-TRAP assay, and the results obtained from the samples using the RTQ-TRAP method were compared with the conventional TRAP method.


RESULTS
The RTQ-TRAP method was both accurate and reproducible in measuring telomerase activity in a dilution series of protein extracts from HL60 cells. Telomerase activity in 13 lymphoma samples, as determined by the RTQ-TRAP method, was ninefold lower than that measured by the conventional TRAP method. The half-life of telomerase activity in human tumor cells, as determined using RTQ-TRAP, was much shorter than the half-life reported previously.


CONCLUSIONS
Our results suggest that the conventional TRAP assay frequently overestimates telomerase activity in tumor samples. The RTQ-TRAP method is thus a useful tool to rapidly and precisely quantify telomerase activity.
Department of Medicine, Division of Hematology, Karolinska Hospital and Institute, SE-171 76 Stockholm, Sweden.
M
M
Hou
D
D
Xu
M
M
Björkholm
A
A
Gruber
D004797:Enzyme-Linked Immunosorbent Assay; D005456:Fluorescent Dyes; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000201:enzymology; D016133:Polymerase Chain Reaction; D012091:Repetitive Sequences, Nucleic Acid; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013601:T-Lymphocytes / Q000201:enzymology; D019098:Telomerase / Q000235:genetics / Q000378:metabolism*; D016615:Telomere / Q000235:genetics*; D014407:Tumor Cells, Cultured
D005456:Fluorescent Dyes; D019098:Telomerase