Reevaluation of the Effect of Iodine on Thyroid Cell Survival and Function Using PCCL3 and Nthy-ori 3-1 Cells

The appropriate amount of iodine is critical for normal function of thyroid cells synthesizing thyroid hormones. Although normal thyroid cell lines such as rat PCCL3 and FRTL5 and human Nthy-ori 3-1 have been widely used for in vitro studies on physiological and pathophysiological effects of iodine on thyroid cells, we have recently pointed out the critical differences between FRTL5/PCCL3 cells and Nthy-ori 3-1 cells. Therefore, we here directly compared some of the cellular characteristics?iodine uptake, differentiated status, iodine-induced cytotoxicity, and iodine-regulation of autophagy?between PCCL3 and Nthy-ori 3-1 cells. PCCL3 cells express messenger RNAs for thyrotropin receptor and sodium/iodine symporter and incorporate iodine in a thyrotropin-dependent manner, whereas Nthy-ori 3-1 cells do not either. Nevertheless, both cells were comparably resistant to iodine cytotoxicity: Only far excess iodine (5 × 10?2 M) killed 20% to 40% cells in 24 hours with perchlorate exhibiting no effect, suggesting this cytotoxic effect is due to extracellular iodine. In contrast, a wide range of iodine (5 × 10?9 to 5 × 10?2 M) induced autophagy in PCCL3 cells, which was abolished by perchlorate, indicating intracellular iodine-induction of autophagy, but this effect was not observed in Nthy-ori 3-1 cells. In conclusion,it is critical to discriminate the effect of iodine incorporated into cells from that of extracellular iodine on thyroid cells. Iodine-uptake competent thyroid cells such as PCCL3 and FRTL5 cells, not Nthy-ori 3-1 cells, should be used for studies on iodine effect on thyroid cells

甲状腺癌細胞におけるSNAIL誘導上皮間葉移行とALDH陰性分画における癌幹細胞様特性

Background: Epithelial-to-mesenchymal transition (EMT) is thought to play a critical role in the invasion and metastasis of cancer and to be associated with cancer stem cell (CSC) properties. It is not clear if there is a link between EMT and CSCs in thyroid cancers. We therefore investigated the CSC properties of thyroid cancers that underwent EMT. Method: To induce EMT (spindle-like cell morphology, loss and acquisition of expression of an epithelial marker E-cadherin and a mesenchymal marker vimentin respectively) in an epithelial-type thyroid cancer cell line ACT-1, we used transforming growth factor-β (TGF-β), BRAFV600E, and/or Snail homolog 1 (SNAI1, also known as SNAIL). CSC properties were analyzed with assays for cell proliferation, chemosensitivity, in vitro and in vivo tumor formation ability, cell surface antigens, and intracellular aldehyde dehydrogenase (ALDH; a known CSC marker) activities. Results: EMT was induced most efficiently by SNAIL (ACT-SNAIL cells), whereas TGF-β and BRAFV600E were less efficient. ACT-SNAIL cells showed slightly but significantly enhanced tumor formation ability in an in vitro sphere assay (approximately 3-fold) but not an in vivo subcutaneous tumor growth assay, and showed comparable chemosensitivity compared with the parental ACT-1 cells. However, of interest, although the in vitro sphere-formation ability of ALDH+ cells was almost unchanged after SNAIL induction, SNAIL overexpression induced much higher (approximately 14-fold) spheres in ALDH- cells. Thus, ALDH was no longer a CSC marker in ACT-SNAIL cells. Conclusions: All these data indicate that EMT confers CSC properties in ALDH- cells and appears to influence the ability of ALDH to enrich CSCs.長崎大学学位論文 学位記番号:博(医歯薬)甲第714号 学位授与年月日:平成26年9月19日Author: Kazuaki Yasui, Mika Shimamura, Norisato Mitsutake, Yuji NagayamaCitation: Thyroid, 23(8), pp.989-996; 2013Nagasaki University (長崎大学)課程博

Characterization of metabolic reprogramming by metabolomics in the oncocytic thyroid cancer cell line XTC.UC1

Oncocytic thyroid cancer is characterized by the aberrant accumulation of abnormal mitochondria in the cytoplasm and a defect in oxidative phosphorylation. We performed metabolomics analysis to compare metabolic reprogramming among the oncocytic and non-oncocytic thyroid cancer cell lines XTC.UC1 and TPC1, respectively, and a normal thyroid cell line Nthy-ori 3-1. We found that although XTC.UC1 cells exhibit higher glucose uptake than TPC1 cells, the glycolytic intermediates are not only utilized to generate end-products of glycolysis, but also diverted to branching pathways such as lipid metabolism and the serine synthesis pathway. Glutamine is preferentially used to produce glutathione to reduce oxidative stress in XTC.UC1 cells, rather than to generate α-ketoglutarate for anaplerotic flux into the TCA cycle. Thus, growth, survival and redox homeostasis of XTC.UC1 cells rely more on both glucose and glutamine than do TPC1 cells. Furthermore, XTC.UC1 cells contained higher amounts of intracellular amino acids which is due to higher expression of the amino acid transporter ASCT2 and enhanced autophagy, thus providing the building blocks for macromolecules and energy production. These metabolic alterations are required for oncocytic cancer cells to compensate their defective mitochondrial function and to alleviate excess oxidative stress

Astrometry of H2_2O masers in the massive star--forming region IRAS 06061+2151 with VERA

We measured the trigonometric annual parallax of H$_2$O maser source associated with the massive star-forming regions IRAS 06061+2151 with VERA. The annual parallax of $0.496\pm0.031$ mas corresponding to a distance of $2.02^{+0.13}_{-0.12}$ kpc was obtained by 10 epochs of observations from 2007 October to 2009 September. This distance was obtained with a higher accuracy than the photometric distance previously measured, and places IRAS 06061+2151 in the Perseus spiral arm. We found that IRAS 06061+2151 also has a peculiar motion of larger than 15 km s$^{-1}$ counter to the Galactic rotation. That is similar to five sources in the Perseus spiral arm, whose parallaxes and proper motions have already been measured with higher accuracy. Moreover, these sources move at on average 27 km s$^{-1}$ toward the Galactic center and counter to the Galactic rotation.Comment: 8 pages, 4 figures, accepted to PAS

Minor contribution of cytotoxic T lymphocyte antigen 4 and programmed cell death 1 ligand 1 in immune tolerance against mouse thyrotropin receptor in mice

We have previously shown that wild type (wt) mice exhibit susceptibility to immunization with human (h) thyrotropin receptor (TSHR), but resistance to mouse (m) TSHR, while TSHR knockout (KO) mice are susceptible to mTSHR, indicating the existence of robust immune tolerance against the mTSHR in wt mice. This tolerance may be mediated by either centrally or peripherally. We here explored the contribution of a peripheral arm of immune tolerance against the mTSHR by using antibodies to deplete regulatory T cells (Tregs), to antagonize co-inhibitory molecules and/or to stimulate co-stimulatory molecules. Antagonistic anti-co-inhibitory molecules, cytotoxic T lymphocyte antigen 4 (CTLA4) and programmed cell death 1 ligand 1 (PDL1), induced only low levels of anti-TSHR antibodies without induction of hyperthyroidism in a mouse Graves\u27model. In this experimental setting, antibody levels were significantly higher in THSR+/- mice than wt mice. However, agonistic anti-co-stimulatory molecules, CD40 and CD137, and Treg-depleting anti-CD25 antibodies showed no effect. All these data suggest that peripheral immune tolerance against the mTSHR may play a minor role, and imply the importance of central tolerance, in immune tolerance against mTSHR in mice. Additional studies on central tolerance to the mTSHR will be necessary for completely delineating the mechanisms for immune tolerance against mTSHR in mice