Telomerase is not activated in human hyperplastic and adenomatous parathyroid tissue

Abstract

Background: Telomerase is a speci®c enzyme that appears to have a key role in cellular senescence and the progression of neoplastic tissue. High telomerase activity has been found in several cancers, but not in most normal and benign tissue. Little is known about the in¯uence of telomerase on the abnormal growth associated with hyperparathyroidism. Objective: To analyse telomerase activity in parathyroid tissue obtained from 29 patients undergoing surgery for primary hyperparathyroidism. Design: Tissue for telomerase activity measurements was collected from six hyperplastic, 20 adenomatous and 22 normal parathyroid glands. Methods: The highly sensitive PCR-based telomeric repeat ampli®cation protocol, TRAP, combined with ELISA, was used to detect telomerase activity in tissue extracts containing 3.0 mg protein.Result: Telomerase was not activated in any of the analysed tissue by 3 mg protein. Reassay of 12 samples containing 6.0 mg protein veri®ed these negative TRAP results. Conclusion: Our ®ndings indicate that telomerase is not a part of the mechanism promoting parathyroid proliferation and the underlying conditions remain to be determined.

Telomerase Activation and Expression of its Catalytic Subunits in Benign and Malignant Tumors of the Parathyroid

“…Results of this real-time PCR method are expressed as a C T value representing the suggested that TA was not involved in the abnormal growth of cells with hyperparathyroidism. 12 Two other reports and our results concurred with these observations. Thus, we suggest that TA is present only in malignant parathyroid tumors.…”

“…12 Total RNA was collected from samples, using a TRI-reagent (Life Technologies, Gaithersburg, MD, USA). One nanogram of total RNA was reverse-transcribed in a 20-µl reaction buffer, containing 1 µl (0.…”

“…9 However, there are only sporadic reports on the activation of telomerase in the parathyroid gland. [10][11][12] According to these reports, TA was found only in parathyroid cancer and was never detected in any benign parathyroid tumors. Although these previous studies reported similar results, to our knowledge the mechanism of TA, including hTERT expression, in parathyroid tumors has never been described.…”

Demonstration of human telomerase reverse transcriptase (hTERT) in human parathyroid tumours by in situ hybridization with a new oligonucleotide probe

“…(1999) reported finding that metastatic tissue from primary parathyroid carcinoma and primary cultured cells from only one patient with a parathyroid carcinoma exhibited a very high telomerase activity according the results of a telomeric repeat amplification protocol (TRAP) assay. Velin et al . (2001) reported that normal, hyperplastic and adenomatous parathyroid tissue were telomerase negative.…”

TERT promoter mutations are rare in parathyroid tumors

“…By contrast, telomerase activity was virtually absent in adenomas (0/47), hyperplasias (0/11), and normal parathyroid tissues (0/23) (Falchetti et al 1999, Velin et al 2001, Kammori et al 2003, Onoda et al 2004. These observations suggest that telomerase activation is necessary for parathyroid malignancy but not for the proliferation of benign lesions.…”