A RAPID, USEFUL AND QUANTITATIVE METHOD TO MEASURE TELOMERASE ACTIVITY BY HYBRIDIZATION PROTECTION ASSAY CONNECTED WITH A TELOMERIC REPEAT AMPLIFICATION PROTOCOL

Telomerase, a ribonucleoprotein enzyme, is expected to be a new marker for cancer diagnosis. TRAP (the telomeric-repeat amplification protoc ol) developed by Kim et al. is a sensitive method to detect telomerase activity. Telomerase activity is detected by TRAP in most malignant c ells in vivo and in vitro, but it is not found, or found only in very low amounts, in normal somatic cells and tissues. TRAP and its modifie d protocols are, however, not always suitable for measuring the activi ty of a large number of clinical samples to diagnose cancer, because t hey generally require a time-consuming detection step such as gel elec trophoresis with radioactive materials. To improve the procedure for m ass diagnosis, we applied a hybridization protection assay (HPA) to re place the detection step. HPA, which employs an acridinium-ester-label led probe, is radioactivity-free, easy to handle without electrophores is, quick, and applicable to a quantitative format. In this work we ha ve established and demonstrated the advantages of TRAP/HPA. The telome rase activity of various primary and established cells, differentiatin g cancer cells, and normal and tumour colorectal and liver tissues was quantitatively analysed by TRAP/HPA. The results indicate that HPA co mbined with TRAP is a rapid and simple method, easy to handle and quan tify, for the clinical diagnosis of cancer.