Thyroglobulin may affect telomerase activity in thyroid follicular cells

Akio Nagasaka, Naohisa Oda, Akira Nakai, Keiko Hotta, Mutsuko Nagata, Taiya Kato, Atsushi Suzuki, Mitsuyasu Itoh, Hitoshi Miura, Motoo Hakuta, Shonen Yoshida, Yatsuka Hibi, Katsumi Iwase

Research output: Contribution to journalArticlepeer-review


Telomerase (TA) activity is known to be present in malignant tumor cells, but not in most somatic differentiated cells. TA shows relatively high activity in thyroid cancer cells, but reports vary. This fact prompted us to elucidate whether cell component inhibitors of TA in the thyroid follicles can modulate its activity. The activity of TA extracted from Hela cells was inhibited by mixing with the supernatant fraction of human thyroid tissue extract. To examine the effect of iodine, thyroid hormones (ℓ-T3 and ℓ-T4) and human thyroglobulin (hTg) contained in the thyroid follicles, ℓ-T3, ℓ-T4 and hTg were added to the TRAP assay system in vitro, using TA from Hela cells. Iodine, ℓ-T3 and ℓ-T4 did not affect TA activity, but hTg inhibited the TA activity in a dose-dependent manner (IC50 of hTg: ca 0.45 μM: inhibiting concentration of hTg was from 0.15 μM to 3.0 μM). The hTg inhibition was not evident in the RT-PCR system, suggesting no effect of hTg on Taq DNA polymerase activity. The hTg inhibition of TA activity was attenuated by dNTP but not significantly by TS primer. These data suggest that hTg contained in thyroid follicular cells of various thyroid diseases may affect the TA activity measured in biopsied thyroid specimens, and that the reduction of the TA activity by hTg may induce slow progression and growth, and low grade malignancy of thyroid cancer, particularly differentiated carcinoma.

Original languageEnglish
Pages (from-to)524-530
Number of pages7
JournalJournal of Enzyme Inhibition and Medicinal Chemistry
Issue number2
Publication statusPublished - 04-2009

All Science Journal Classification (ASJC) codes

  • Pharmacology
  • Drug Discovery


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