Nonradioisotopic telomeric repeat amplification protocol (TRAP) using digoxigenin labeled probe

We have attempted to detect telomerase activity by Southern blot analysis using a digoxigenin labeled probe (5'-(CCCTTA)₆CCCTAA-3'). Telomerase activity was detected in all cancer cell lines that were tested, and:the lower limit for detection was 10³ cells. Although telomerase activity was detected in colon cancer tissues, it was not found in adenoma or normal tissues. Telomerase activity was completely abrogated by heat and RNase treatment of the CHAPS extract. Our results demonstrate that this nonradioisotopic assay is safe and reliable for detecting telomerase activity in cancer cell lines and biopsy samples.