TY - JOUR
T1 - Thyroglobulin may affect telomerase activity in thyroid follicular cells
AU - Nagasaka, Akio
AU - Oda, Naohisa
AU - Nakai, Akira
AU - Hotta, Keiko
AU - Nagata, Mutsuko
AU - Kato, Taiya
AU - Suzuki, Atsushi
AU - Itoh, Mitsuyasu
AU - Miura, Hitoshi
AU - Hakuta, Motoo
AU - Yoshida, Shonen
AU - Hibi, Yatsuka
AU - Iwase, Katsumi
N1 - Copyright:
Copyright 2010 Elsevier B.V., All rights reserved.
PY - 2009/4
Y1 - 2009/4
N2 - 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.
AB - 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.
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U2 - 10.1080/14756360802218920
DO - 10.1080/14756360802218920
M3 - Article
C2 - 18830915
AN - SCOPUS:68049091986
SN - 1475-6366
VL - 24
SP - 524
EP - 530
JO - Journal of Enzyme Inhibition and Medicinal Chemistry
JF - Journal of Enzyme Inhibition and Medicinal Chemistry
IS - 2
ER -