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Waugh DT. Fluoride Exposure Induces Inhibition of Sodium/Iodide Symporter (NIS) Contributing to Impaired Iodine Absorption and Iodine Deficiency: Molecular Mechanisms of Inhibition and Implications for Public Health. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:E1086. [PMID: 30917615 PMCID: PMC6466022 DOI: 10.3390/ijerph16061086] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 03/19/2019] [Accepted: 03/21/2019] [Indexed: 12/24/2022]
Abstract
The sodium iodide symporter (NIS) is the plasma membrane glycoprotein that mediates active iodide transport in the thyroid and other tissues, such as the salivary, gastric mucosa, rectal mucosa, bronchial mucosa, placenta and mammary glands. In the thyroid, NIS mediates the uptake and accumulation of iodine and its activity is crucial for the development of the central nervous system and disease prevention. Since the discovery of NIS in 1996, research has further shown that NIS functionality and iodine transport is dependent on the activity of the sodium potassium activated adenosine 5'-triphosphatase pump (Na+, K+-ATPase). In this article, I review the molecular mechanisms by which F inhibits NIS expression and functionality which in turn contributes to impaired iodide absorption, diminished iodide-concentrating ability and iodine deficiency disorders. I discuss how NIS expression and activity is inhibited by thyroglobulin (Tg), tumour necrosis factor alpha (TNF-α), transforming growth factor beta 1 (TGF-β1), interleukin 6 (IL-6) and Interleukin 1 beta (IL-1β), interferon-γ (IFN-γ), insulin like growth factor 1 (IGF-1) and phosphoinositide 3-kinase (PI3K) and how fluoride upregulates expression and activity of these biomarkers. I further describe the crucial role of prolactin and megalin in regulation of NIS expression and iodine homeostasis and the effect of fluoride in down regulating prolactin and megalin expression. Among many other issues, I discuss the potential conflict between public health policies such as water fluoridation and its contribution to iodine deficiency, neurodevelopmental and pathological disorders. Further studies are warranted to examine these associations.
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Affiliation(s)
- Declan Timothy Waugh
- EnviroManagement Services, 11 Riverview, Doherty's Rd, Bandon, Co. Cork, P72 YF10, Ireland.
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Zhao Y, Zhong L, Yi H. A review on the mechanism of iodide metabolic dysfunction in differentiated thyroid cancer. Mol Cell Endocrinol 2019; 479:71-77. [PMID: 30287400 DOI: 10.1016/j.mce.2018.09.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 09/06/2018] [Accepted: 09/07/2018] [Indexed: 12/27/2022]
Abstract
The incidence of differentiated thyroid cancer (DTC) has been increasing rapidly worldwide, and the risk factors remain unclear. With the growing number of patients with DTC, the related issues have been gradually highlighted. 131Iodide (131I) is an important treatment for DTC and has the potential to reduce the risk of recurrence. 131I is also an effective treatment for distant metastases of thyroid carcinoma. However, iodide metabolism dysfunction in metastatic foci causes patients to lose the opportunity of 131I treatment. This article reviews the related mechanisms of iodide metabolism dysfunction in DTC cells and summarizes the clinical transformation progression.
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Affiliation(s)
- Yinlong Zhao
- Department of Nuclear Medicine, Second Hospital of Jilin University, Changchun, Jilin Province, 130041, PR China.
| | - Lili Zhong
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetic, Second Hospital of Jilin University, Changchun, 130041, PR China.
| | - Heqing Yi
- Department of Nuclear Medicine, Zhejiang Cancer Hospital, Key Laboratory of Head & Neck Cancer Translational Research of Zhejiang, 310021, PR China.
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Alotaibi H, Tuzlakoğlu-Öztürk M, Tazebay UH. The Thyroid Na+/I- Symporter: Molecular Characterization and Genomic Regulation. Mol Imaging Radionucl Ther 2017; 26:92-101. [PMID: 28117294 PMCID: PMC5283716 DOI: 10.4274/2017.26.suppl.11] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Iodide (I-) is an essential constituent of the thyroid hormones triiodothyronine (T3) and thyroxine (T4), and the iodide concentrating mechanism of the thyroid gland is essential for the synthesis of these hormones. In addition, differential uptake of iodine isotopes (radioiodine) is a key modality for the diagnosis and therapy of thyroid cancer. The sodium dependent iodide transport activity of the thyroid gland is mainly attributed to the functional expression of the Na+/I- Symporter (NIS) localized at the basolateral membrane of thyrocytes. In this paper, we review and summarize current data on molecular characterization, on structure and function of NIS protein, as well as on the transcriptional regulation of NIS encoding gene in the thyroid gland. We also propose that a better and more precise understanding of NIS gene regulation at the molecular level in both healthy and malignant thyroid cells may lead to the identification of small molecule candidates. These could then be translated into clinical practice for better induction and more effective modulation of radioiodine uptake in dedifferentiated thyroid cancer cells and in their distant metastatic lesions.
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Affiliation(s)
| | | | - Uygar Halis Tazebay
- Gebze Technical University, Department of Molecular Biology and Genetics, Kocaeli, Turkey, Phone: +90 262 605 25 22, E-mail:
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Wittmann G, Mohácsik P, Balkhi MY, Gereben B, Lechan RM. Endotoxin-induced inflammation down-regulates L-type amino acid transporter 1 (LAT1) expression at the blood-brain barrier of male rats and mice. Fluids Barriers CNS 2015; 12:21. [PMID: 26337286 PMCID: PMC4559167 DOI: 10.1186/s12987-015-0016-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 08/18/2015] [Indexed: 11/13/2022] Open
Abstract
Background We recently reported that bacterial lipopolysaccharide (LPS)-induced inflammation decreases the expression of the primary thyroid hormone transporters at the blood–brain barrier, organic anion-transporting polypeptide 1c1 (OATP1c1) and monocarboxylate transporter 8 (MCT8). l-type amino acid transporters 1 and 2 (LAT1 & LAT2) are regarded as secondary thyroid hormone transporters, and are expressed in cells of the blood–brain or blood-cerebrospinal fluid barrier and by neurons. The purpose of this study was to examine the effect of LPS-induced inflammation on the expression of LAT1 and LAT2, as these may compensate for the downregulation of OATP1c1 and MCT8. Methods LPS (2.5 mg/kg body weight) was injected intraperitoneally to adult, male, Sprague–Dawley rats and C57Bl/6 mice, which were euthanized 2, 4, 9, 24 or 48 h later. LAT1 and LAT2 mRNA expression were studied on forebrain sections using semiquantitative radioactive in situ hybridization. LAT1 protein levels in brain vessels were studied using LAT1 immunofluorescence. Statistical comparisons were made by the non-parametric Kruskal–Wallis and Dunn’s tests. Results In both species, LAT1 mRNA decreased in brain blood vessels as soon as 2 h after LPS injection and was virtually undetectable at 4 h and 9 h. During recovery from endotoxemia, 48 h after LPS injection, LAT1 mRNA in brain vessels increased above control levels. A modest but significant decrease in LAT1 protein levels was detected in the brain vessels of mice at 24 h following LPS injection. LPS did not affect LAT1 and LAT2 mRNA expression in neurons and choroid plexus epithelial cells. Conclusions The results demonstrate that LPS-induced inflammation rapidly decreases LAT1 mRNA expression at the blood–brain barrier in a very similar manner to primary thyroid hormone transporters, while changes in LAT1 protein level follow a slower kinetics. The data raise the possibility that inflammation may similarly down-regulate other blood–brain barrier transport systems at the transcriptional level. Future studies are required to examine this possibility and the potential pathophysiological consequences of inflammation-induced changes in blood–brain barrier transport functions. Electronic supplementary material The online version of this article (doi:10.1186/s12987-015-0016-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Gábor Wittmann
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Tupper Research Institute, Tufts Medical Center, Boston, MA, USA.
| | - Petra Mohácsik
- Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary. .,Semmelweis University, János Szentágothai PhD School of Neurosciences, Budapest, Hungary.
| | - Mumtaz Yaseen Balkhi
- Division of Hematology/Oncology, Department of Medicine, Tupper Research Institute, Tufts Medical Center, Boston, MA, USA.
| | - Balázs Gereben
- Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.
| | - Ronald M Lechan
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Tupper Research Institute, Tufts Medical Center, Boston, MA, USA. .,Department of Neuroscience, Tufts University School of Medicine, Boston, MA, USA.
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Yao C, Pan Y, Li Y, Xu X, Lin Y, Wang W, Wang S. Effect of sodium/iodide symporter (NIS)-mediated radioiodine therapy on estrogen receptor-negative breast cancer. Oncol Rep 2015; 34:59-66. [PMID: 25955347 DOI: 10.3892/or.2015.3946] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 02/05/2015] [Indexed: 11/06/2022] Open
Abstract
Since the sodium/iodide symporter (NIS) stimulates the iodine uptake in normal lactating breast, our study aimed to study the effect of NIS-mediated radioiodide therapy on ER-negative breast cancers. A recombinant lentivirus plasmid encoding the human NIS (hNIS) gene and firefly luciferase (Fluc) was constructed. MDA-MB-231 cells were transfected with the recombinant lentivirus, and the hNIS gene expression was identified by western blot analysis and real-time PCR. Tissue-specific expression of the NIS gene was confirmed by immunohistochemical (IHC) staining. Functional NIS activity in the MDA-hNIS cells was confirmed by the uptake of 131I and cytotoxicity assays. The relative expression level of hNIS mRNA exhibited a 10-fold higher expression in the MDA-hNIS cells compared with the level in the control cells without the endogenous NIS gene. Abundant expression of hNIS protein was noted in the cell membrane compared to the cytoplasm which confirmed the efficient expression of the functional hNIS gene. Iodine uptake into the MDA-hNIS cells was rapid, reaching a maximum after 15 min, followed by a decline. Exposure of the MDA-hNIS cells with 131I resulted in a time-dependent reduction in colony formation compared with the survival of the control (MDA) cells. Our results confirmed that NIS overexpression enhances the sensitivity of ER-negative breast cancer cells to radioiodide therapy.
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Affiliation(s)
- Chen Yao
- Department of Vascular, Thyroid and Breast Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Yi Pan
- Southern Medical University, Guangzhou, Guangdong 510080, P.R. China
| | - Yongxin Li
- Department of Vascular, Thyroid and Breast Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Xiangdong Xu
- Department of Vascular, Thyroid and Breast Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Ying Lin
- Department of Vascular, Thyroid and Breast Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Wenjian Wang
- Laboratory of the Department of Surgery, The First Affiliated Hospital, Sun Yat‑sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Shenming Wang
- Department of Vascular, Thyroid and Breast Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China
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Darrouzet E, Lindenthal S, Marcellin D, Pellequer JL, Pourcher T. The sodium/iodide symporter: state of the art of its molecular characterization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:244-53. [PMID: 23988430 DOI: 10.1016/j.bbamem.2013.08.013] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 08/05/2013] [Accepted: 08/19/2013] [Indexed: 12/30/2022]
Abstract
The sodium/iodide symporter (NIS or SLC5A5) is an intrinsic membrane protein implicated in iodide uptake into thyroid follicular cells. It plays a crucial role in iodine metabolism and thyroid regulation and its function is widely exploited in the diagnosis and treatment of benign and malignant thyroid diseases. A great effort is currently being made to develop a NIS-based gene therapy also allowing the radiotreatment of nonthyroidal tumors. NIS is also expressed in other tissues, such as salivary gland, stomach and mammary gland during lactation, where its physiological role remains unclear. The molecular identity of the thyroid iodide transporter was elucidated approximately fifteen years ago. It belongs to the superfamily of sodium/solute symporters, SSS (and to the human transporter family, SLC5), and is composed of 13 transmembrane helices and 643 amino acid residues in humans. Knowledge concerning NIS structure/function relationship has been obtained by taking advantage of the high resolution structure of one member of the SSS family, the Vibrio parahaemolyticus sodium/galactose symporter (vSGLT), and from studies of gene mutations leading to congenital iodine transport defects (ITD). This review will summarize current knowledge regarding the molecular characterization of NIS.
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Affiliation(s)
- Elisabeth Darrouzet
- SBTN, bât 170, centre de Marcoule, BP 17171, 30207 Bagnols sur Cèze CEDEX, France; Laboratoire TIRO, Faculté de médecine, Université de Nice Sophia-Antipolis, 28 Avenue de Valombrose, 06107 Nice CEDEX, France; CAL, TIRO, F-06107 Nice, France.
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Serrano-Nascimento C, Calil-Silveira J, Goulart-Silva F, Nunes MT. New insights about the posttranscriptional mechanisms triggered by iodide excess on sodium/iodide symporter (NIS) expression in PCCl3 cells. Mol Cell Endocrinol 2012; 349:154-61. [PMID: 22001309 DOI: 10.1016/j.mce.2011.09.036] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Revised: 09/06/2011] [Accepted: 09/24/2011] [Indexed: 10/17/2022]
Abstract
Iodide excess acutely downregulates NIS mRNA expression, as already demonstrated. PCCl3 cells treated or not with NaI, NaI+NaClO(4) or NaI+Methimazole, for 30 min to 24 h, were used to further explore how iodide reduces NIS gene expression. NIS mRNA expression was evaluated by Real-Time PCR; its poly(A) tail length, by RACE-PAT; its translation rate, by polysome profile; total NIS content, by Western blotting. NIS mRNA decay rate was evaluated in actinomycin-D-treated cells, incubated with or without NaI for 0-6 h. Iodide treatment caused a reduction in NIS mRNA expression, half-life, poly(A) tail length, recruitment to ribosomes, as well as NIS protein expression. Perchlorate, but not methimazole, prevented these effects. Therefore, reduced poly(A) tail length of NIS mRNA seems to be related to its decreased half-life, in addition to its translation impairment. These data provide new insights about the molecular mechanisms involved in the rapid and posttranscriptional inhibitory effect of iodide on NIS expression.
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Affiliation(s)
- Caroline Serrano-Nascimento
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, 05508-000 São Paulo, SP, Brazil
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Poole A, Saghir SA. Diiodomethyl-p-tolylsulfone: evaluation of the mode of action for reproductive toxicity. Regul Toxicol Pharmacol 2011; 62:504-12. [PMID: 22166729 DOI: 10.1016/j.yrtph.2011.11.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Revised: 11/14/2011] [Accepted: 11/28/2011] [Indexed: 11/29/2022]
Abstract
The mode of action (MOA) underpinning the reproductive toxicity of diiodomethyl-p-tolylsulfone (DIMPTS) is excess systemic iodine levels, resulting in hypothyroidism. This MOA evaluation also addresses the potential for toxicity and adverse health outcomes during critical windows of development for different tissues. The data indicate that testicular development in the neonate represents the tissue and life-stage that are most sensitive to iodine toxicity. Life-stage specific dosimetry appears to be a major determinant of this sensitivity, with the neonate being exposed to higher levels of iodine than the fetus during the period of testicular development, in particular Sertoli cell maturation and differentiation. While no reports could be found in the literature linking excess iodine exposure in humans to testicular toxicity, there is evidence that neonates born to mothers with excessive iodine intake do exhibit signs of transient hypothyroidism. Although there are major physiological and temporal differences in testicular development and Sertoli cell replication between the rat and human, it is not inconceivable that continuous long term exposures to excess iodine first from maternal milk and then in the diet through to the onset of puberty could affect testicular development. However, exposures to iodinated substances - such as DIMPTS - contribute less than 1% of the required daily iodine intake for normal fetal and neonatal development and, consequently, continuous exposure to excess iodine during the pre-pubertal period is unlikely. As exposures to DIMPTS are both very low and sporadic in nature it is not likely that they represent any risk to health at any life-stage.
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Affiliation(s)
- Alan Poole
- Toxicology and Environmental Research and Consulting, Dow Europe GmbH, Bachtobelstrasse 3, CH-8810 Horgen, Switzerland.
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MicroRNA miR-146b-5p regulates signal transduction of TGF-β by repressing SMAD4 in thyroid cancer. Oncogene 2011; 31:1910-22. [PMID: 21874046 DOI: 10.1038/onc.2011.381] [Citation(s) in RCA: 153] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
MicroRNAs (miRNA) are small non-coding RNAs involved in post-transcriptional gene regulation that have crucial roles in several types of tumors, including papillary thyroid carcinoma (PTC). miR-146b-5p is overexpressed in PTCs and is regarded as a relevant diagnostic marker for this type of cancer. A computational search revealed that miR-146b-5p putatively binds to the 3' untranslated region (UTR) of SMAD4, an important member of the transforming growth factor β (TGF-β) signaling pathway. The TGF-β pathway is a negative regulator of thyroid follicular cell growth, and the mechanism by which thyroid cancer cells evade its inhibitory signal remains unclear. We questioned whether the modulation of the TGF-β pathway by miR-146b-5p can contribute to thyroid tumorigenesis. Luciferase reporter assay confirmed the direct binding of miR-146b-5p on the SMAD4 3'UTR. Specific inhibition of miR-146b-5p with a locked nucleic acid-modified anti-miR-146b oligonucleotide significantly increased SMAD4 levels in the human papillary carcinoma cell lines, TPC-1 and BCPAP. Moreover, suppression of miR-146b-5p increased the cellular response to the TGF-β anti-proliferative signal, significantly decreasing the proliferation rate. The overexpression of miR-146b-5p in normal rat follicular PCCL3 cells decreased SMAD4 levels and disrupted TGF-β signal transduction. MiR-146b-5p overexpression in PCCL3 cells also significantly increased cell proliferation in the absence of thyroid-stimulating hormone and conferred resistance to TGF-β-mediated cell-cycle arrest. Additionally, the activation of thyroid most common oncogenes RET/PTC3 and BRAF in PCCL3 cells upregulated miR-146b-5p expression. Our results confirm the oncogenic role of miR-146b-5p in thyroid follicular cells and contribute to knowledge regarding the modulation of TGF-β signal transduction by miRNAs in PTCs.
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Hingorani M, Spitzweg C, Vassaux G, Newbold K, Melcher A, Pandha H, Vile R, Harrington K. The biology of the sodium iodide symporter and its potential for targeted gene delivery. Curr Cancer Drug Targets 2010; 10:242-67. [PMID: 20201784 DOI: 10.2174/156800910791054194] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Accepted: 02/16/2010] [Indexed: 12/12/2022]
Abstract
The sodium iodide symporter (NIS) is responsible for thyroidal, salivary, gastric, intestinal and mammary iodide uptake. It was first cloned from the rat in 1996 and shortly thereafter from human and mouse tissue. In the intervening years, we have learned a great deal about the biology of NIS. Detailed knowledge of its genomic structure, transcriptional and post-transcriptional regulation and pharmacological modulation has underpinned the selection of NIS as an exciting approach for targeted gene delivery. A number of in vitro and in vivo studies have demonstrated the potential of using NIS gene therapy as a means of delivering highly conformal radiation doses selectively to tumours. This strategy is particularly attractive because it can be used with both diagnostic (99mTc, 125I, 124I)) and therapeutic (131I, 186Re, 188Re, 211At) radioisotopes and it lends itself to incorporation with standard treatment modalities, such as radiotherapy or chemoradiotherapy. In this article, we review the biology of NIS and discuss its development for gene therapy.
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Affiliation(s)
- Mohan Hingorani
- The Institute of Cancer Research, 237 Fulham Road, London SW36JB, UK
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Lecat-Guillet N, Ambroise Y. Enhanced iodide sequestration by 3-biphenyl-5,6-dihydroimidazo[2,1-b]thiazole in sodium/iodide symporter (NIS)-expressing cells. ChemMedChem 2008; 3:1211-6. [PMID: 18470848 DOI: 10.1002/cmdc.200800052] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The ability of the sodium/iodide symporter (NIS) to take up iodide has long provided the basis for cytoreductive gene therapy and cancer treatment with radioiodide. One of the major limitations of this approach is that radioiodide retention in NIS-expressing cells is not sufficient for their destruction. We identified and characterized a small organic molecule capable of increasing iodide retention in HEK293 cells permanently transfected with human NIS cDNA (hNIS-HEK293) and in the rat thyroid-derived cell line FRTL-5. In the presence of 3-biphenyl-4'-yl-5,6-dihydroimidazo[2,1-b]thiazole (ISA1), the transmembrane iodide concentration gradient was increased up to 4.5-fold. Our experiments indicate that the imidazothiazole derivative acts either by inhibiting anion efflux mechanisms, or by promoting the relocation of iodide into subcellular compartments. This new compound is not only an attractive chemical tool to investigate the mechanisms of iodide flux at the cellular level, but also opens promising perspectives in the treatment of cancer after NIS gene transfer.
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Affiliation(s)
- Nathalie Lecat-Guillet
- Department of Bioorganic Chemistry and Isotopic Labelling, CEA, Institute of Biology and Technology, Gif sur Yvette 91191, France
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Haberkorn U. Modulation of tracer accumulation in malignant tumors: gene expression, gene transfer, and phage display. Curr Top Dev Biol 2008; 70:145-69. [PMID: 16338341 DOI: 10.1016/s0070-2153(05)70007-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Assessment of gene function following the completion of human genome sequencing may be done using radionuclide imaging procedures. These procedures are needed for the evaluation of genetically manipulated animals or new designed biomolecules which requires a thorough understanding of physiology, biochemistry and pharmacology. The experimental approaches will involve many new technologies including in vivo imaging with SPECT and PET. Nuclear medicine procedures may be applied for the determination of gene function and regulation using established and new tracers or using in vivo reporter genes such as genes encoding enzymes, receptors, antigens or transporters. Visualization of in vivo reporter gene expression can be done using radiolabeled substrates, antibodies or ligands. Combinations of specific promoters and in vivo reporter genes may deliver information about the regulation of the corresponding genes. Furthermore, protein-protein interactions and activation of signal transduction pathways may be visualized non-invasively. The role of radiolabeled antisense molecules for the analysis of mRNA content has to be investigated. However, possible applications are therapeutic intervention using triplex oligonucleotides with therapeutic isotopes which can be brought near to specific DNA sequences to induce DNA strand breaks at selected loci. Imaging of labeled siRNA's makes sense if these are used for therapeutic purposes in order to assess the delivery of these new drugs to their target tissue. Finally, new biomolecules will be developed by bioengineering methods which may be used for isotope-based diagnosis and treatment of disease.
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Affiliation(s)
- Uwe Haberkorn
- Department of Nuclear Medicine, University of Heidelberg Clinical Cooperation Unit Nuclear Medicine German Cancer Research Center, Heidelberg, Germany
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Beyer SJ, Jimenez RE, Shapiro CL, Cho JY, Jhiang SM. Do cell surface trafficking impairments account for variable cell surface sodium iodide symporter levels in breast cancer? Breast Cancer Res Treat 2008; 115:205-12. [PMID: 18500672 DOI: 10.1007/s10549-008-0059-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Accepted: 05/08/2008] [Indexed: 11/30/2022]
Abstract
The Na(+)/I(-) symporter (NIS) is a transmembrane glycoprotein that mediates iodide uptake into thyroid follicular cells and serves as the molecular basis of radioiodine imaging and therapy for thyroid cancer patients. The finding that NIS protein is present in 80-90% of breast tumors suggests that breast cancer patients may also benefit from NIS-mediated radionuclide imaging and targeted therapy. However, only 17-25% of NIS-positive breast tumors have detectable radionuclide uptake activity. The discrepancy between NIS expression and radionuclide uptake activity is most likely contributed by variable cell surface NIS protein levels. Apart from the prevalent view that NIS cell surface trafficking impairments account for the variability, our current study proposes that differential levels of NIS expression may also account for variable cell surface NIS levels among breast tumors. We address the need to confirm the identity of intracellular NIS staining to reveal the mechanisms underlying variable cell surface NIS levels. In addition, we warrant a quantitative correlation between cell surface NIS levels and radionuclide uptake activity in patients such that the cell surface NIS levels required for radionuclide imaging can be defined and the defects impairing NIS activity can be recognized.
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Affiliation(s)
- S J Beyer
- Integrated Biomedical Sciences Graduate Program, The Ohio State University, Columbus, OH 43210, USA
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Li H, Richard K, McKinnon B, Mortimer RH. Effect of Iodide on Human Choriogonadotropin, Sodium-Iodide Symporter Expression, and Iodide Uptake in BeWo Choriocarcinoma Cells. J Clin Endocrinol Metab 2007; 92:4046-51. [PMID: 17726079 DOI: 10.1210/jc.2006-2358] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Active placental transport of maternal iodide by the thyroidal sodium iodide symporter (NIS) provides an essential substrate for fetal thyroid hormone synthesis. NIS is expressed in trophoblast and is regulated by human choriogonadotropin (hCG). In thyroid, iodide down-regulates expression of several genes including NIS. Placentas of iodine-deficient rats demonstrate up-regulation of NIS mRNA, suggesting a role for iodide in regulating placental NIS. OBJECTIVES AND METHODS The objectives were to examine effects of iodide on expression of NIS and hCG in BeWo choriocarcinoma cells. Gene expression was studied by quantitative real-time PCR. Effects on NIS protein expression were assessed by Western blotting. Functional activity of NIS was measured by (125)I uptake. Expression of hCG protein was assessed by immunoassay of secreted hormone. RESULTS Iodide inhibited NIS mRNA and membrane protein expression as well as (125)I uptake, which were paralleled by decreased betahCG mRNA expression and protein secretion. Iodide had no effects on pendrin expression. Addition of hCG increased NIS mRNA expression. This effect was partially inhibited by addition of iodide. The inhibitory effects of iodide on NIS mRNA expression were abolished by propylthiouracil and dithiothreitol. CONCLUSIONS We conclude that expression of placental NIS is modulated by maternal iodide. This may occur through modulation of hCG effects on NIS and hCG gene expression.
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Affiliation(s)
- Huika Li
- Department of Endocrinology, Conjoint Endocrine Laboratory, Royal Brisbane and Women's Hospital and Queensland Health Pathology Services, Brisbane, Queensland 4029, Australia
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Dayem M, Navarro V, Marsault R, Darcourt J, Lindenthal S, Pourcher T. From the molecular characterization of iodide transporters to the prevention of radioactive iodide exposure. Biochimie 2006; 88:1793-806. [PMID: 16905238 DOI: 10.1016/j.biochi.2006.07.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Accepted: 07/19/2006] [Indexed: 12/23/2022]
Abstract
In the event of a nuclear reactor accident, the major public health risk will likely result from the release and dispersion of volatile radio-iodines. Upon body exposure and food ingestion, these radio-iodines are concentrated in the thyroid, resulting in substantial thyroidal irradiation and accordingly causing thyroid cancers. Stable potassium iodide (KI) effectively blocks thyroid iodine uptake and is thus used in iodide prophylaxis for reactor accidents. The efficiency of KI is directly related to the physiological inhibition of the thyroid function in the presence of high plasma iodide concentrations. This regulation is called the Wolff-Chaikoff effect. However, to be fully effective, KI should be administered shortly before or immediately after radioiodine exposure. If KI is provided only several hours after exposure, it will elicit the opposite effect e.g. lead to an increase in the thyroid irradiation dose. To date, clear evaluation of the benefit and the potential toxicity of KI administration remain difficult, and additional data are needed. We outline in this review the molecular characterization of KI-induced regulation of the thyroid function. Significant advances in the knowledge of the iodide transport mechanisms and thyroid physiology have been made. Recently developed molecular tools should help clarify iodide metabolism and the Wolff-Chaikoff effect. The major goals are clarifying the factors which increase thyroid cancer risk after a reactor accident and improving the KI administration protocol. These will ultimately lead to the development of novel strategies to decrease thyroid irradiation after radio-iodine exposure.
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Affiliation(s)
- M Dayem
- Unité TIRO (Transporter in Imaging and Radiotherapy in Oncology), Commissariat à l'énergie atomique DSV-DIEP-SBTN, School of Medicine, University of Nice Sophia Antipolis, 28, avenue de Valombrose, 06107 Nice cedex, France
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17
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Josefsson M, Evilevitch L, Weström B, Grunditz T, Ekblad E. Sodium-iodide symporter mediates iodide secretion in rat gastric mucosa in vitro. Exp Biol Med (Maywood) 2006; 231:277-81. [PMID: 16514173 DOI: 10.1177/153537020623100306] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
In vivo studies on rats have demonstrated that considerable amounts of iodide are transported from the bloodstream into the gastric lumen. The mechanisms for and functional significance of this transport are poorly understood. Active (driven by Na(+)/K(+)-ATPase) iodide transport into thyroid follicular cells is mediated by the sodium-iodide symporter (NIS), which is also abundantly expressed in gastric mucosa. We aimed to further investigate the iodide transport in gastric mucosa and the possible role of NIS in this transport process. Iodide transport in rat gastric mucosa was studied in vitro in an Ussing chamber system using (125)I as a marker. The system allows measurements in both directions over a mucosal specimen. A considerable transport of iodide (from the serosal to the mucosal side) was established across the gastric mucosa, whereas in the opposite direction (mucosa to serosa), iodide transport was negligible. Sodium perchlorate (NaClO(4)), a competitive inhibitor of NIS, and ouabain, an inhibitor of the Na(+)/K(+)-ATPase, both attenuated gastric iodide transport from the serosal to the mucosal side. To investigate a possible neuroendocrine regulation of the iodide transport identified to occur from the serosal to the mucosal side of the stomach, thyroid-stimulating hormone (TSH), thyrotropin-releasing hormone (TRH), vasoactive intestinal peptide (VIP), histamine, or nitric oxide donor S-nitroso-N-acetyl-D,L-penicillamine (SNAP) was added. None of these substances influenced the iodide transport. We conclude that iodide is actively transported into the gastric lumen and that this transport is at least partly mediated by NIS. Additional investigations are needed to understand the regulation and significance of this transport.
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Affiliation(s)
- Malin Josefsson
- Department of Clinical Medical Science, Section for Otorhinolaryngology, Malmö University Hospital, University of Lund, Sweden
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18
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Radović B, Schmutzler C, Köhrle J. Xanthohumol stimulates iodide uptake in rat thyroid-derived FRTL-5 cells. Mol Nutr Food Res 2005; 49:832-6. [PMID: 16092068 DOI: 10.1002/mnfr.200500053] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Sodium-iodide-symporter (NIS), an integral plasma membrane glycoprotein, mediates the sodium-dependent active uptake of iodide (I(-)) into the thyroid gland, which is a fundamental step in thyroid hormone synthesis. In this work, we analyzed the influence of xanthohumol (XN), a prenylated chalcone from hops (Humulus lupulus L.), on the I(-) uptake in a cell culture model of normal, nontransformed rat thyrocytes (FRTL-5). Acute treatment with nanomolar concentrations of XN does not influence I(-) uptake, but after 2 and 3-days of XN stimulation an increase in I(-) uptake was observed; I(-) uptake was maximally increased by 50% compared to control after 3-days of XN stimulation at 1 nM. A clear time-dependent stimulation was observed which showed no marked concentration relationship, however. To investigate whether expression of NIS mRNA is also increased, we grew FRTL-5 cells for 3-days in a medium containing increasing concentrations of XN (0.1 nM-1 muM). Northern blot analysis showed no difference in NIS mRNA transcript levels between control cells and those treated with different concentrations of XN. This study revealed that nanomolar concentrations of XN, a unique compound with anticancer properties, exert stimulating effects on radioiodide uptake. In contrast to many other plant-derived phenolic secondary metabolites such as (iso-)flavonoids, which inhibit I(-) uptake, XN might be an interesting candidate for more efficient radioiodide therapy of thyroid and perhaps other cancer expressing NIS such as breast cancer.
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Affiliation(s)
- Branislav Radović
- Institut für Experimentelle Endokrinologie und Endokrinologisches, Forschungszentrum EnForCé, Charité Universitätsmedizin Berlin, Berlin, Germany.
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19
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Trouttet-Masson S, Selmi-Ruby S, Bernier-Valentin F, Porra V, Berger-Dutrieux N, Decaussin M, Peix JL, Perrin A, Bournaud C, Orgiazzi J, Borson-Chazot F, Franc B, Rousset B. Evidence for transcriptional and posttranscriptional alterations of the sodium/iodide symporter expression in hypofunctioning benign and malignant thyroid tumors. THE AMERICAN JOURNAL OF PATHOLOGY 2004; 165:25-34. [PMID: 15215159 PMCID: PMC1618532 DOI: 10.1016/s0002-9440(10)63272-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The uptake of iodide by epithelial thyroid cells requires the expression of a specific transporter, the Na(+)/I(-) symporter, NIS. Benign and malignant thyroid tumors of epithelial origin show a decrease up to a loss of iodide uptake activity. Previous studies of the human NIS (hNIS) gene expression in these tumors, based on the amplification of transcripts and/or immunohistochemical detection of the protein, have yielded divergent data; hNIS expression was found either increased or decreased. To get a new and integrated view of the alterations of hNIS expression in hypofunctioning thyroid tumors, we performed investigations of hNIS transcript and hNIS protein levels on the same tumors and paired normal tissue samples. HNIS, identified as a 75- to 80-kd species, was present in all normal tissue samples from euthyroid patients, but was undetectable, even at high membrane protein input, in all benign and malignant hypofunctioning thyroid tumors. By contrast, approximately 50% of tumors contained hNIS transcripts. This dissociation between transcript and protein levels was not found for the transcript and protein encoded by the PDS gene assayed in the same tumors. The hNIS transcript-positive tumors contained small amounts of low-molecular mass hNIS-immunoreactive species identified as nonglycosylated hNIS. Tumors containing the nonmature form of hNIS exhibited a predominant intracellular immunolabeling. In conclusion, our data show that benign and malignant hypofunctioning thyroid tumors either no longer express hNIS protein or express only a very low amount of nonglycosylated hNIS and indicate that the impairment of hNIS gene expression might result from alterations at both transcriptional and posttranscriptional levels.
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Affiliation(s)
- Séverine Trouttet-Masson
- UMR369 INSERM /Université Claude Bernard-Lyon 1 and Institut Fédératif de Recherche 62, Faculté de Médecine Lyon-RTH Laennec, Rue Guillaume Paradin, 69372 Lyon Cedex 08, France.
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20
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Chun JT, Di Dato V, D'Andrea B, Zannini M, Di Lauro R. The CRE-like element inside the 5'-upstream region of the rat sodium/iodide symporter gene interacts with diverse classes of b-Zip molecules that regulate transcriptional activities through strong synergy with Pax-8. Mol Endocrinol 2004; 18:2817-29. [PMID: 15319451 DOI: 10.1210/me.2004-0020] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We previously demonstrated that transcription of the rat sodium/iodide symporter (NIS) gene is regulated by NUE, an upstream enhancer located between nucleotides -2264 and -2495 of the 5'-flanking region. To elucidate the mechanism of TSH/cAMP-mediated regulation of NIS gene expression, we have characterized the putative cAMP response element (CRE)/activator protein (AP)-1 site (termed NUC) that is closely located between the two Pax-8 (paired box domain transcription factor-8) binding sites within NUE. In two different approaches using either gel supershift analyses or dominant-negative inhibitors of b-Zip molecules, we have shown that NUC can be recognized by several members of the AP-1 and CREB family transcription factors that modulate the transcriptional activity of NUE. Using tethered dimers of b-Zip molecules, we have also demonstrated that specific homo- or heterodimers of AP-1 can synergistically stimulate NUE activity in concert with Pax-8. To demonstrate further that NUC is a bona fide CRE, we made an artificial promoter with the five-time tandem repeat of this sequence (5xNUC). In comparison to the canonical CRE (5xCRE), 5xNUC manifested greater transcriptional activity and broader response to cAMP signaling. Hence, we postulate that the significance of this evolutionally conserved CRE-like site may lie in its broader cell type specificity.
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Affiliation(s)
- J T Chun
- Department of Biochemistry and Molecular Biology, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli, Italy
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21
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Haberkorn U, Altmann A, Mier W, Eisenhut M. Impact of functional genomics and proteomics on radionuclide imaging. Semin Nucl Med 2004; 34:4-22. [PMID: 14735455 DOI: 10.1053/j.semnuclmed.2003.09.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The assessment of gene function following the completion of human genome sequencing may be performed using radionuclide imaging procedures. These procedures are needed for the evaluation of genetically manipulated animals or newly designed biomolecules, which requires a thorough understanding of physiology, biochemistry, and pharmacology. The experimental approaches will involve many new technologies, including in vivo imaging with single photon emission computed tomography and positron emission tomography. Nuclear medicine procedures may be applied for the determination of gene function and regulation using established and new tracers, or using in vivo reporter genes, such as genes encoding enzymes, receptors, antigens, or transporters. Visualization of in vivo reporter gene expression can be performed using radiolabeled substrates, antibodies, or ligands. Combinations of specific promoters and in vivo reporter genes may deliver information about the regulation of the corresponding genes. Furthermore, protein-protein interactions and activation of signal transduction pathways may be visualized noninvasively. The role of radiolabeled antisense molecules for the analysis of messenger ribonucleic acid (RNA) content has to be investigated. However, possible applications are therapeutic intervention using triplex oligonucleotides with therapeutic isotopes, which can be brought near to specific deoxyribonucleic acid sequences to induce deoxyribonucleic acid strand breaks at selected loci. Imaging of labeled siRNA makes sense if these are used for therapeutic purposes to assess the delivery of these new drugs to their target tissue. Pharmacogenomics will identify new surrogate markers for therapy monitoring, which may represent potential new tracers for imaging. Drug distribution studies for new therapeutic biomolecules are needed at least during preclinical stages of drug development. New treatment modalities, such as gene therapy with suicide genes, will need procedures for therapy planning and monitoring. Finally, new biomolecules will be developed by bioengineering methods, which may be used for the isotope-based diagnosis and treatment of disease.
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Affiliation(s)
- Uwe Haberkorn
- Department of Nuclear Medicine, University of Heidelberg, Germany.
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22
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Affiliation(s)
- Orsolya Dohán
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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23
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Abstract
The Na(+)/I(-) symporter (NIS) is a plasma membrane glycoprotein that mediates active iodide uptake in the thyroid-the essential first step in thyroid hormone biosynthesis-and in other tissues, such as salivary and lactating mammary glands. Thyroidal radioiodide uptake has been used for over 60 years in the diagnosis and effective treatment of thyroid cancer and other diseases. However, the NIS cDNA was only isolated in 1996 by expression cloning in Xenopus laevis oocytes, marking the beginning of the molecular characterization of NIS and the study of its regulation, both in the thyroid and other tissues. One of the most exciting current areas of NIS research-radioiodide treatment of extrathyroidal cancers-was launched by the discovery of functional expression of endogenous NIS in breast cancer and by the ectopic transfer of the NIS gene into otherwise non NIS-expressing cancers. This review summarizes the main findings in NIS research, emphasizing the most recent developments.
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Affiliation(s)
- Orsolya Dohán
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
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24
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Haberkorn U, Kinscherf R, Kissel M, Kübler W, Mahmut M, Sieger S, Eisenhut M, Peschke P, Altmann A. Enhanced iodide transport after transfer of the human sodium iodide symporter gene is associated with lack of retention and low absorbed dose. Gene Ther 2003; 10:774-80. [PMID: 12704416 DOI: 10.1038/sj.gt.3301943] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Transfer of the sodium iodide symporter (hNIS) has been proposed as a new principle of cancer gene therapy. Using clinically relevant doses of (131)I for the treatment of NIS-expressing prostate carcinoma cells, we investigated the kinetics and the absorbed doses obtained in these tumors. hNIS-expressing cell lines accumulated up to 200 times more iodide when compared to wild-type cells. However, a rapid efflux of the radioactivity (80%) occurred during the first 20 min after replacement of the medium. In rats, the hNIS-expressing tumors accumulated up to 20 times more iodide when compared to contralateral transplanted wild-type tumors. After 24 h and doses of 550, 1200 or 2400 MBq/m(2) hNIS-expressing tumors lost 89, 89 and 91% of the initial activity, respectively. Dosimetric calculations showed that 1200 MBq/m(2) resulted in 3+/-0.5 Gy (wild-type tumor 0.15+/-0.1 Gy) and 2400 MBq/m(2) resulted in 3.1+/-0.9 Gy (wild-type tumor 0.26+/-0.02 Gy). Although transduction of the hNIS gene induces iodide transport in rat prostate adenocarcinoma a rapid efflux occurs, which leads to a low absorbed dose in genetically modified tumors. With regard to a therapeutic application additional conditions need to be defined leading to iodide trapping.
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Affiliation(s)
- U Haberkorn
- Department of Nuclear Medicine, University of Heidelberg, Heidelberg, Germany
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25
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Sieger S, Jiang S, Schönsiegel F, Eskerski H, Kübler W, Altmann A, Haberkorn U. Tumour-specific activation of the sodium/iodide symporter gene under control of the glucose transporter gene 1 promoter (GTI-1.3). Eur J Nucl Med Mol Imaging 2003; 30:748-56. [PMID: 12541134 DOI: 10.1007/s00259-002-1099-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Targeted transfer of a functionally active sodium iodide symporter (NIS) into tumour cells may be used for radioiodine therapy of cancer. Therefore, we investigated radioiodine uptake in a hepatoma cell line in vitro and in vivo after transfer of the sodium iodide symporter ( hNIS) gene under the control of a tumour-specific regulatory element, the promoter of the glucose transporter 1 gene (GTI-1.3). Employing a self-inactivating bicistronic retroviral vector for the transfer of the hNIS and the hygromycin resistance genes, rat Morris hepatoma (MH3924A) cells were infected with retroviral particles and hNIS-expressing cell lines were generated by hygromycin selection. (125)I(-) uptake and efflux were determined in genetically modified and wild type hepatoma cells. In addition, the iodide distribution in rats bearing wild type and genetically modified hepatomas was monitored. hNIS-expressing MH3924A cell lines accumulated up to 30 times more iodide than wild type hepatoma cells, with a maximal iodide uptake after 30 min incubation time. Competition experiments in the presence of sodium perchlorate revealed a decrease in the iodide uptake (80-84% decrease). Moreover, ouabain led to a loss of accumulated I(-) (81% decrease) whereas 4,4'-diisothiocyano-2,2'-disulphonic acid stilbene (DIDS) increased the I(-) uptake into cells (87% increase). However, a rapid efflux of the radioactivity (70%) was observed 20 min after (125)I(-)-containing medium had been replaced by non-radioactive medium. Lithium had no significant effect on iodide efflux. In rats, the hNIS-expressing tumours accumulated 22 times more iodide than the contralateral wild type tumour. In accordance with the in vitro data, we also observed a rapid efflux of the radioactivity out of the tumour in vivo. Dosimetric calculations resulted in an absorbed dose of 85 mGy in the wild type tumour and 830 mGy in the hNIS-expressing tumour after administration of 18.5 MBq (131)I. In conclusion, transduction of the hNIS gene under the control of the GLUT1 promoter element induces iodide transport in Morris hepatoma cells in vitro and in vivo. However, for therapeutic application additional conditions need to be defined which inhibit the iodide efflux out of the tumour cells.
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Affiliation(s)
- Stephanie Sieger
- Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Centre, Heidelberg, Germany
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26
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Selmi-Ruby S, Watrin C, Trouttet-Masson S, Bernier-Valentin F, Flachon V, Munari-Silem Y, Rousset B. The porcine sodium/iodide symporter gene exhibits an uncommon expression pattern related to the use of alternative splice sites not present in the human or murine species. Endocrinology 2003; 144:1074-85. [PMID: 12586784 DOI: 10.1210/en.2002-220971] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The sodium/iodide symporter (NIS) is a membrane protein mediating the active transport of iodide into the thyroid gland. NIS, expressed by human, rat, and mouse thyrocytes, is encoded by a single transcript. We identified NIS mRNA species of 3.5 and 3 kb in porcine thyrocytes. Because porcine thyrocytes in primary culture is a widely used experimental system for thyroid iodide metabolism, we further examined the origin and the function of the porcine NIS (pNIS) transcripts. We generated a porcine thyroid cDNA library from which four different clones, pNIS-D, F, J, and Delta J were isolated. pNIS-D encodes a protein of 643 amino acids highly homologous to the human, rat, and mouse NIS. pNIS-F and J differ from each other and from pNIS-D in their C-terminal part. pNIS-Delta J lacks a six-amino-acid segment within the putative transmembrane domain 10. Transiently expressed in Cos-7 cells, the four pNIS-cDNAs led to the synthesis of proteins targeted at the plasma membrane and conferred perchlorate-sensitive iodide uptake activities to Cos-7 cells, except pNIS-Delta J, which was devoid of activity. PNIS-D probably derives from the 3.5-kb transcript and pNIS-F, J, and Delta J from the 3-kb transcript. The relative abundance of pNIS-D, F, and J transcripts in porcine thyrocytes was about 60%, 35%, and 5%, respectively; the Delta J transcript was not present in detectable amount. By comparing porcine NIS genomic and cDNA sequences, splice donor and acceptor sites accounting for the generation of pNIS-F, J, and Delta J transcripts were identified. None of the combinations of alternative splice sites found in the pig was present in the human, rat or mouse NIS gene. Our data show that porcine NIS gene, contrary to the NIS gene from other species, gives rise to splice variants leading to three active and one inactive NIS proteins.
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Affiliation(s)
- Samia Selmi-Ruby
- Institut National de la Santé et de la Recherche Médicale, Unité 369, Institut Fédératif de Recherche Laennec, 69372 Lyon, Cedex 08, France
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27
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Dohán O, De la Vieja A, Paroder V, Riedel C, Artani M, Reed M, Ginter CS, Carrasco N. The sodium/iodide Symporter (NIS): characterization, regulation, and medical significance. Endocr Rev 2003; 24:48-77. [PMID: 12588808 DOI: 10.1210/er.2001-0029] [Citation(s) in RCA: 534] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The Na(+)/I(-) symporter (NIS) is an integral plasma membrane glycoprotein that mediates active I(-) transport into the thyroid follicular cells, the first step in thyroid hormone biosynthesis. NIS-mediated thyroidal I(-) transport from the bloodstream to the colloid is a vectorial process made possible by the selective targeting of NIS to the basolateral membrane. NIS also mediates active I(-) transport in other tissues, including salivary glands, gastric mucosa, and lactating mammary gland, in which it translocates I(-) into the milk for thyroid hormone biosynthesis by the nursing newborn. NIS provides the basis for the effective diagnostic and therapeutic management of thyroid cancer and its metastases with radioiodide. NIS research has proceeded at an astounding pace after the 1996 isolation of the rat NIS cDNA, comprising the elucidation of NIS secondary structure and topology, biogenesis and posttranslational modifications, transcriptional and posttranscriptional regulation, electrophysiological analysis, isolation of the human NIS cDNA, and determination of the human NIS genomic organization. Clinically related topics include the analysis of congenital I(-) transport defect-causing NIS mutations and the role of NIS in thyroid cancer. NIS has been transduced into various kinds of cancer cells to render them susceptible to destruction with radioiodide. Most dramatically, the discovery of endogenous NIS expression in more than 80% of human breast cancer samples has raised the possibility that radioiodide may be a valuable novel tool in breast cancer diagnosis and treatment.
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Affiliation(s)
- Orsolya Dohán
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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28
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Abstract
Flavonoids have inhibiting effects on the proliferation of cancer cells, including thyroidal ones. In the treatment of thyroid cancer the uptake of iodide is essential. Flavonoids are known to interfere with iodide organification in vitro, and to cause goiter. The influence of flavonoids on iodine metabolism was studied in a human thyroid cancer cell line (FTC-133) transfected with the human sodium/iodide transporter (NIS). All flavonoids inhibited growth, and iodide uptake was decreased in most cells. NIS mRNA expression was affected during the early hours after treatment, indicating that these flavonoids can act on NIS. Pendrin mRNA expression did not change after treatment. Only myricetin increased iodide uptake. Apeginin, luteolin, kaempferol and F21388 increased the efflux of iodide, leading to a decreased retention of iodide. Instead myricetin increased the retention of iodide; this could be of use in the radioiodide treatment of thyroid cancer.
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29
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Taki K, Kogai T, Kanamoto Y, Hershman JM, Brent GA. A thyroid-specific far-upstream enhancer in the human sodium/iodide symporter gene requires Pax-8 binding and cyclic adenosine 3',5'-monophosphate response element-like sequence binding proteins for full activity and is differentially regulated in normal and thyroid cancer cells. Mol Endocrinol 2002; 16:2266-82. [PMID: 12351692 DOI: 10.1210/me.2002-0109] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The sodium/iodide symporter (NIS) gene is highly expressed in the thyroid gland and is important for the diagnosis and radioiodide therapy of differentiated thyroid cancers. We investigated a human NIS (hNIS) gene 5'-far-upstream enhancer (hNUE) (-9847 to -8968). The hNUE is TSH responsive in both FRTL-5 cells and primary normal thyroid cells, but not in human papillary thyroid cancer cells (BHP cells). The hNUE enhanced expression of the basal hNIS promoter 15-fold and required both a Pax-8 binding site and a cAMP response element (CRE)-like sequence for full activity. The hNUE activated transcription in a thyroid-selective and cAMP-dependent manner, mediated by both protein kinase A (PKA)-dependent and PKA-independent pathways. Pax-8 and two CRE-like sequence binding proteins bind to the hNUE. Supershift binding assay indicated that one of the CRE-like sequence binding protein(s) was CRE-binding protein-1, activation transcription factor-1, and/or CRE modulator, and the other was an unknown factor(s) that is absent in BHP 2-7 cells. A far-upstream enhancer is important for hNIS regulation in the thyroid. Deficient CRE-like sequence binding protein(s) that bind to the hNUE in normal thyroid cells may be responsible for reduced NIS gene expression in some thyroid carcinomas.
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Affiliation(s)
- Katsumi Taki
- Endocrinology Division, Veterans Affairs Greater Los Angeles Healthcare System and Department of Medicine, University of California-Los Angeles School of Medicine, Los Angeles, California 90073, USA
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30
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Josefsson M, Grunditz T, Ohlsson T, Ekblad E. Sodium/iodide-symporter: distribution in different mammals and role in entero-thyroid circulation of iodide. ACTA PHYSIOLOGICA SCANDINAVICA 2002; 175:129-37. [PMID: 12028133 DOI: 10.1046/j.1365-201x.2002.00968.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
UNLABELLED The sodium (Na+)/iodide (I-)-symporter (NIS) is abundantly expressed and accumulates iodide in thyroid follicular cells. The NIS is also found in extrathyroidal tissues, particularly gastric mucosa. Controversies exist on the localization of extrathyroidal NIS. We have studied the presence of both NIS peptide and NIS messenger RNA (mRNA) in the digestive tract and thyroid from different mammals. The role of gastric NIS is enigmatic and we aimed to unravel its possible involvement in iodide transport. METHODS Distribution and expression of NIS were studied using immunocytochemistry and in situ hybridization. Iodide transport in the gastrointestinal tract was measured after oral or intravenous (i.v.) administration of 125I to rats with or without ligation of the pylorus. RESULTS All thyroid follicular cells in rat and mouse expressed NIS, whereas a patchy staining was noted in man, pig and guinea-pig. Gastric mucosa surface epithelium in all species and ductal cells of parotid gland in guinea-pig, rat and mouse expressed NIS. In parietal cells and in endocrine cells of intestines and pancreas NIS immunoreactivity but no NIS mRNA was found. Studies of 125I uptake showed marked iodide transport from the circulation into the gastric lumen. CONCLUSIONS The localization of NIS varies slightly among mammals. To establish expression of NIS in a particular cell type the need to correlate the presence of both NIS protein by immunocytochemistry and NIS mRNA by in situ hybridization is emphasized. An entero-thyroidal circulation of iodide mediated principally by gastric NIS, but possibly also by NIS in salivary glands is suggested.
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Affiliation(s)
- M Josefsson
- Department of Physiological Sciences, Section for Neuroendocrine Cell Biology, University of Lund, Sweden
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31
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Riedel C, Dohán O, De la Vieja A, Ginter CS, Carrasco N. Journey of the iodide transporter NIS: from its molecular identification to its clinical role in cancer. Trends Biochem Sci 2001; 26:490-6. [PMID: 11504625 DOI: 10.1016/s0968-0004(01)01904-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The Na+/I- symporter (NIS) is an intrinsic plasma membrane protein that mediates the active transport of I- in the thyroid, lactating mammary gland, stomach and salivary glands. The presence of NIS in the thyroid is exploited in diagnostic scintigraphic imaging and radioiodide therapy in thyroid cancer. The continued rapid progress in NIS research (aimed at the elucidation of the Na+-dependent I- transport mechanism, the analysis of NIS structure-function relations and the study of the tissue-specific regulation of NIS at all levels), holds potentially far-reaching medical applications beyond thyroid disease, in breast cancer and malignancies in other tissues.
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Affiliation(s)
- C Riedel
- Albert Einstein College of Medicine, Dept of Molecular Pharmacology, 1300 Morris Park Ave., Bronx, NY 10461, USA
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Riedel C, Levy O, Carrasco N. Post-transcriptional regulation of the sodium/iodide symporter by thyrotropin. J Biol Chem 2001; 276:21458-63. [PMID: 11290744 DOI: 10.1074/jbc.m100561200] [Citation(s) in RCA: 193] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Na(+)/I(-) symporter (NIS) is a key plasma membrane glycoprotein that mediates active I(-) transport in the thyroid gland (Dai, G., Levy, O., and Carrasco, N. (1996) Nature 379, 458-460), the first step in thyroid hormone biogenesis. Whereas relatively little is known about the mechanisms by which thyrotropin (TSH), the main hormonal regulator of thyroid function, regulates NIS activity, post-transcriptional events have been suggested to play a role (Kaminsky, S. M., Levy, O., Salvador, C., Dai, G., and Carrasco, N. (1994) Proc. Natl. Acad. Sci. U. S. A. 91, 3789-3793). Here we show that TSH induces de novo NIS biosynthesis and modulates the long NIS half-life ( approximately 5 days). In addition, we demonstrate that TSH is required for NIS targeting to or retention in the plasma membrane. We further show that NIS is a phosphoprotein and that TSH modulates its phosphorylation pattern. These results provide strong evidence of the major role played by post-transcriptional events in the regulation of NIS by TSH. Beyond their inherent interest, it is also of medical significance that these TSH-dependent regulatory mechanisms may be altered in the large proportion of thyroid cancers in which NIS is predominantly expressed in intracellular compartments, instead of being properly targeted to the plasma membrane.
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Affiliation(s)
- C Riedel
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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33
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Liou MJ, Lin JD, Chan EC, Liu FH, Chao TC, Weng HF. Detection of mRNA of sodium iodide symporter in benign and malignant human thyroid tissues. Cancer Lett 2000; 160:75-80. [PMID: 11098087 DOI: 10.1016/s0304-3835(00)00565-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Human sodium iodide symporter (hNIS) is an intrinsic membrane protein with 12 transmembrane regions, which shows homology to other sodium-dependent transporters. There is controversy as to the amount of hNIS expression in different kinds of human thyroid cancer tissues and cell lines. In this study, reverse transcription-polymerase chain reaction (RT-PCR) was used to detect mRNA of hNIS in various fresh normal, benign tissues and malignant human thyroid tissues. The forward primer was nested hNIS-5' primer containing the sequences: ACCTGGAAATGCGCTTCAGC. The reverse primer was nested hNIS-3' primer containing the sequences: AAGCATGACACCGCGTGCCA. The results revealed three of three normal tissues, six of eight nodular hyperplasia, two of two hyperthyroidism, one of three follicular adenomas, five of ten papillary thyroid carcinomas, one of one follicular carcinoma and zero of one metastatic follicular tissues demonstrated positive results for hNIS in thyroid epithelial cells. A higher percentage of positive results of the symporter mRNA were found in normal benign thyroid tissues and the thyroid tissues of hyperthyroidism, and nodular hyperplasia (84.6%); however follicular adenoma, papillary and follicular thyroid carcinomas demonstrated a lower percentage of expression in the RT-PCR studies (46.7%). Serum thyrotropin levels and the degree of differentiated components presented in cancer tissues have been mentioned as important factors for hNIS expression in the cancer tissues. The discrepancies of the expression of hNIS in in vivo and in vitro studies need further investigation. In conclusion, hNIS was found in higher ratios in normal and benign thyroid tissues than in the malignant tissues. In addition, the RT-PCR technique hNIS did not detect the transporter in most papillary thyroid cancer tissues.
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Affiliation(s)
- M J Liou
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Chang Gung Memorial Hospital, Chang Gung University, 5 Fu-Shin St., Kweishan Village, Taoyuan, PR, Taiwan, China
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De La Vieja A, Dohan O, Levy O, Carrasco N. Molecular analysis of the sodium/iodide symporter: impact on thyroid and extrathyroid pathophysiology. Physiol Rev 2000; 80:1083-105. [PMID: 10893432 DOI: 10.1152/physrev.2000.80.3.1083] [Citation(s) in RCA: 209] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The Na(+)/I(-) symporter (NIS) is an intrinsic membrane protein that mediates the active transport of iodide into the thyroid and other tissues, such as salivary glands, gastric mucosa, and lactating mammary gland. NIS plays key roles in thyroid pathophysiology as the route by which iodide reaches the gland for thyroid hormone biosynthesis and as a means for diagnostic scintigraphic imaging and for radioiodide therapy in hyperthyroidism and thyroid cancer. The molecular characterization of NIS started with the 1996 isolation of a cDNA encoding rat NIS and has since continued at a rapid pace. Anti-NIS antibodies have been prepared and used to study NIS topology and its secondary structure. The biogenesis and posttranslational modifications of NIS have been examined, a thorough electrophysiological analysis of NIS has been conducted, the cDNA encoding human NIS (hNIS) has been isolated, the genomic organization of hNIS has been elucidated, the regulation of NIS by thyrotropin and I(-) has been analyzed, the regulation of NIS transcription has been studied, spontaneous NIS mutations have been identified as causes of congenital iodide transport defect resulting in hypothyroidism, the roles of NIS in thyroid cancer and thyroid autoimmune disease have been examined, and the expression and regulation of NIS in extrathyroidal tissues have been investigated. In gene therapy experiments, the rat NIS gene has been transduced into various types of human cells, which then exhibited active iodide transport and became susceptible to destruction with radioiodide. The continued molecular analysis of NIS clearly holds the potential of an even greater impact on a wide spectrum of fields, ranging from structure/function of transport proteins to the diagnosis and treatment of cancer, both in the thyroid and beyond.
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Affiliation(s)
- A De La Vieja
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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Abstract
In addition to physiologic, diagnostic, and therapeutic implications, the recently cloned and characterized sodium iodide symporter (NIS) also may play an important role in the pathogenesis of autoimmune thyroid disease. Sodium iodide symporter expression patterns characteristically are changed in autoimmune thyroid disease, including Graves' disease and Hashimoto's thyroiditis, which may be caused, in part, by the regulation of sodium iodide symporter expression of cytokines involved in the pathogenesis of autoimmune thyroid disease. Further, there is increasing evidence that NIS-directed antibodies are present in sera from patients with autoimmune thyroid disease, and these antibodies also may affect NIS functional activity.
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Affiliation(s)
- C Spitzweg
- Mayo Medical School, Rochester, Minnesota, USA
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Lin JD, Chan EC, Chao TC, Chen KT, Hsueh C, Ho YS, Weng HF. Expression of sodium iodide symporter in metastatic and follicular human thyroid tissues. Ann Oncol 2000; 11:625-9. [PMID: 10907960 DOI: 10.1023/a:1008340402577] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Active iodide uptake across the basal membrane mediated by human sodium iodide symporter (hNIS) has been shown to be a process coupled with the flow of sodium. There is still controversy as to the amount of hNIS expression present in different kinds of human thyroid cancer tissues. In this study, we present a 58-year-old women with follicular thyroid carcinoma with vertebra and skull metastases. 201Tl and 5 mCi 131I scans clearly demonstrated the metastatic lesions in the brain of this patient. Thyroid and metastatic tissues were then obtained for this study, which is aimed at comparing the iodide trapping ability in vivo and in vitro of hNIS, and then comparing their expression in both thyroid tissue and metastatic tissues. Polyclonal antibodies to hNIS and competitive RT PCR were used to analyze the symporter protein and mRNA expressed in follicular human thyroid and metastatic tissues. Positive staining of the symporter protein was performed in the follicular thyroid carcinomas, otherwise, the metastatic tissues could not have demonstrated the protein in the staining. Follicular thyroid carcinoma tissues from thyroid were revealed around 5 pg hNIS expressed in follicular thyroid carcinoma tissues from the thyroid. Otherwise, there was almost an absence of hNIS expression in the metastatic tissue. These discrepancies of the expression in hNIS in vivo and in vitro studies need further investigation.
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Affiliation(s)
- J D Lin
- Department of Internal Medicine, Chang Gung Memorial Hospital, Taoyuan Hsien, Taiwan, Republic of China
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Affiliation(s)
- S M Jhiang
- Departments of Physiology and Internal Medicine, Ohio State University, 302 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210, USA.
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Dohan O, De la Vieja A, Carrasco N. Molecular study of the sodium-iodide symporter (NIS): a new field in thyroidology. Trends Endocrinol Metab 2000; 11:99-105. [PMID: 10707050 DOI: 10.1016/s1043-2760(00)00237-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The active transport of iodide into the thyroid is mediated by the Na(+)-I- symporter (NIS), an intrinsic membrane protein. NIS plays key roles in thyroid pathophysiology as the route by which I- reaches the gland for thyroid hormone biosynthesis, and as a means for diagnostic scintigraphic imaging and for radioiodide therapy in thyroid cancer. The molecular characterization of NIS started with the isolation in 1996 of a cDNA encoding rat NIS, and has subsequently led to a virtually new field in thyroidology. The research reviewed in this article clearly has far-reaching implications in the areas of structure/function of transport proteins, thyroid pathophysiology, hormone action mechanisms, cell differentiation and cancer.
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Affiliation(s)
- O Dohan
- Albert Einstein College of Medicine, Department of Molecular Pharmacology, 1300 Bronx, NY 10461, USA
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Spitzweg C, Joba W, Morris JC, Heufelder AE. Regulation of sodium iodide symporter gene expression in FRTL-5 rat thyroid cells. Thyroid 1999; 9:821-30. [PMID: 10482376 DOI: 10.1089/thy.1999.9.821] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The sodium iodide symporter (NIS), first identified in FRTL-5 cells, plays a critical role in iodide transport in the thyroid gland and in the production of the iodine-containing thyroid hormones. The aim of our study was to examine the regulation of NIS RNA steady-state levels and protein expression as well as functional activity in FRTL-5 cells. FRTL-5 cells cycling in media containing thyrotropin (TSH) were incubated for 48 hours with dexamethasone (10(-8)-10(-5) M), triiodothyronine (T3; 10(-9)-10(-6) M), methimazole (100 microM), propylthiouracil (PTU; 100 microM), perchlorate (10 microM) and potassium iodide (40 microM). In other experiments, cells were treated for 48 hours with various cytokines including interleukin-6 (IL-6) (100 U/mL), interferon-gamma (IFN-gamma) (100 U/mL), tumor necrosis factor-alpha (TNF-alpha) (10 ng/ml), IL-1alpha (100 U/mL), and IL-1beta (100 U/mL). Northern blot analysis using a 32P-labeled rat NIS-specific cDNA probe (nucleotides 1397-1937) revealed NIS mRNA as a single species of approximately 3 kb. When normalized for beta-actin mRNA signal intensities, NIS RNA steady-state levels in viable FRTL-5 cells were suppressed by approximately 80% after incubation with dexamethasone and T3 in a concentration-dependent manner. Iodide accumulation was decreased by up to 40% after incubation with dexamethasone and T3, respectively, in a concentration-dependent manner. Using a rabbit polyclonal rNIS-specific antibody, Western blot analysis of FRTL-5 cell membranes revealed a 60% and 70% suppression of NIS protein expression after treatment with T3 (0.1 microM) and dexamethasone (1 microM), respectively. In additon, NIS RNA steady-state levels were decreased by approximately 50% after treatment of monolayers with methimazole, PTU, and potassium iodide, respectively. Incubation with methimazole and PTU resulted in a 20% and 25% decrease of iodide accumulation, respectively, whereas potassium iodide suppressed iodide accumulation by approximately 50%. Treatment of FRTL-5 cells with IL-6 and IL-1beta resulted in a 30% decrease of NIS RNA steady-state levels. IL-6 did not alter NIS functional activity, but IL-1beta suppressed iodide accumulation by approximately 25%. IFN-gamma and perchlorate failed to alter NIS RNA steady-state levels. In contrast to IFN-gamma that had no effect on iodide accumulation, perchlorate almost completely suppressed iodide accumulation. TNF-alpha and IL-1alpha failed to alter NIS RNA steady-state levels in higher passage numbers of FRTL-5 cells, whereas treatment with TNF-alpha and IL-1alpha of early passages of FRTL-5 cells (<20 cell passages) resulted in a 70% and 40% decrease of NIS RNA steady-state levels, respectively, and in a 20% suppression of NIS functional activity. In conclusion, our data suggest that various agents known to affect iodide transport are capable of differentially altering NIS gene expression and function in cultured thyroid cells. Suppression of NIS gene expression and function by certain cytokines may be responsible, at least in part, for the impaired radioiodine uptake by thyroid tissue in certain forms of thyroiditis.
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Affiliation(s)
- C Spitzweg
- Division of Endocrinology, Mayo Clinic, Rochester, Minnesota 55905, USA.
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Ohno M, Zannini M, Levy O, Carrasco N, di Lauro R. The paired-domain transcription factor Pax8 binds to the upstream enhancer of the rat sodium/iodide symporter gene and participates in both thyroid-specific and cyclic-AMP-dependent transcription. Mol Cell Biol 1999; 19:2051-60. [PMID: 10022892 PMCID: PMC83998 DOI: 10.1128/mcb.19.3.2051] [Citation(s) in RCA: 180] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The gene encoding the Na/I symporter (NIS) is expressed at high levels only in thyroid follicular cells, where its expression is regulated by the thyroid-stimulating hormone via the second messenger, cyclic AMP (cAMP). In this study, we demonstrate the presence of an enhancer that is located between nucleotides -2264 and -2495 in the 5'-flanking region of the NIS gene and that recapitulates the most relevant aspects of NIS regulation. When fused to either its own or a heterologous promoter, the NIS upstream enhancer, which we call NUE, stimulates transcription in a thyroid-specific and cAMP-dependent manner. The activity of NUE depends on the four most relevant sites, identified by mutational analysis. The thyroid-specific transcription factor Pax8 binds at two of these sites. Mutations that interfere with Pax8 binding also decrease transcriptional activity of the NUE. Furthermore, expression of Pax8 in nonthyroid cells results in transcriptional activation of NUE, strongly suggesting that the paired-domain protein Pax8 plays an important role in NUE activity. The NUE responds to cAMP in both protein kinase A-dependent and -independent manners, indicating that this enhancer could represent a novel type of cAMP responsive element. Such a cAMP response requires Pax8 but also depends on the integrity of a cAMP responsive element (CRE)-like sequence, thus suggesting a functional interaction between Pax8 and factors binding at the CRE-like site.
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Affiliation(s)
- M Ohno
- Stazione Zoologica 'Anton Dohrn', 80121 Naples, Italy
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41
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Abstract
There are several thyroid antigens including human sodium iodide symporter (hNIS), thyrotropin receptor (TSH-R), thyroid peroxidase (TPO), and thyroglobulin (Tg) that have been considered to be thyroid-specific proteins involved in the pathogenesis of autoimmune thyroid diseases. We examined the expression of these thyroid-tolerance related genes in normal human thymus, the lymphoid organ responsible for the induction of central T-cell self. Reverse transcription-polymerase chain reaction (RT-PCR) amplifications were performed with 4 pairs of oligonucleotide primers specific for the hNIS, TSH-R, TPO, and Tg genes, respectively. Gene-specific transcripts were confirmed by Southern hybridization using digoxigenin-labeled internal oligonucleotide probes. To monitor cDNA integrity and quantity, all samples were coamplified with a pair of intron-spanning human beta-actin-specific oligonucleotide primers. Furthermore, using a highly sensitive immunostaining technique and antibodies specific for these 4 antigens, we examined whether NIS-, TSH-R-, TPO-, and Tg-specific immunoreactivity can be detected and localized in normal human thymus. RT-PCR and Southern hybridization revealed expression of each of these 4 thyroid-related genes in normal human thymus. In addition, immunohistochemical analysis of frozen tissue sections derived from normal human thymus showed marked immunoreactivity for NIS, TSH-R, and Tg as well as weaker staining for TPO. Control reactions using isotype matched nonimmune immunoglobulins were consistently negative. Taken together, our results suggest that NIS-, TSH-R-, TPO-, and Tg-RNA are present and actively processed to immunoreactive NIS-, TSH-R-, TPO-, and Tg-like protein in human thymus. These data support the concept that pre-T lymphocytes may be educated to recognize thyroid-related epitopes expressed in thymus, and, thus, to generate self-tolerance against these thyroid-related antigens.
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Affiliation(s)
- C Spitzweg
- Department of Endocrinology, Mayo Clinic, Rochester, Minnesota, USA
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42
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Abstract
Thyroid hormone is an essential regulator of developmental growth and metabolism in vertebrates. Iodine is a necessary constituent of thyroid hormone. Due to the scarcity and uneven distribution of iodine on the Earth's crust, the structure of the thyroid gland is adjusted to collect and store this element in order to secure a continuous supply of thyroid hormone throughout life. Still, disease resulting from hypothyroidism due to iodine deficiency is a global health problem, illustrating the great biological significance that iodine saving mechanisms have evolved. Iodide is accumulated together with prohormone (thyroglobulin) in the lumen of the thyroid follicles. The rate-limiting step of this transport is the sodium/iodide symporter located in the basolateral plasma membrane of the thyroid follicular cells. Iodide is also transferred across the apical plasma membrane into the lumen where hormonogenesis takes place. In this review, recent progress in the understanding of transepithelial iodide transport in the thyroid is summarized.
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Affiliation(s)
- M Nilsson
- Institute of Anatomy and Cell Biology, Göteborg University, Sweden.
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Kotani T, Ogata Y, Yamamoto I, Aratake Y, Kawano JI, Suganuma T, Ohtaki S. Characterization of gastric Na+/I- symporter of the rat. CLINICAL IMMUNOLOGY AND IMMUNOPATHOLOGY 1998; 89:271-8. [PMID: 9837697 DOI: 10.1006/clin.1998.4595] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Characterization of gastric Na+/I- symporter (NIS) of the rat was carried out. Sequencing of the open reading frame of gastric NIS mRNA showed only three nucleotide changes when compared with FRTL-5 NIS cDNA, and two of these changes led to amino acid changes. The results of Northern blot analysis showed that abundant NIS mRNA was expressed in the stomach when compared with other organs. Western blot analysis using gastric mucosa and FRTL-5 lysates detected the difference in molecular weight between FRTL-5 and gastric mucosa lysates, suggesting abnormal posttranslational modification of gastric NIS protein. Immunohistochemically, gastric NIS protein was located in the cornification layer of the stratified squamous epithelium of the pars proventricularis and in parietal cells and on the apical border of surface epithelial cells of the pars glandularis. Gastric NIS protein was present in tubulovesicular structures and lysosomes in parietal cells by immunoelectron microscopy. Gastric NIS protein exists to trap I- from the gastric lumen, except in parietal cells. Results indicated that a very large amount of gastric NIS mRNA is expressed to be translated, whereas only a small amount of immature gastric NIS protein is detected. This may indicate that immature gastric NIS protein rapidly degrades to peptides.
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Affiliation(s)
- T Kotani
- Department of Laboratory Medicine, Miyazaki Medical College, Japan
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Paire A, Bernier-Valentin F, Rabilloud R, Watrin C, Selmi-Ruby S, Rousset B. Expression of alpha- and beta-subunits and activity of Na+K+ ATPase in pig thyroid cells in primary culture: modulation by thyrotropin and thyroid hormones. Mol Cell Endocrinol 1998; 146:93-101. [PMID: 10022767 DOI: 10.1016/s0303-7207(98)00192-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Na+ K+ ATPase located at the basolateral pole of thyroid epithelial cells, contributes to thyroid hormone synthesis by generating the driving force for the uptake of the substrate, iodide. We have investigated whether the expression of the alpha- and beta-subunits and activity of Na+ K+ ATPase were subjected to variations in response, (a) to TSH, that controls the expression of differentiation in thyroid cells and (b) to thyroid hormones as potential autocrine factors. Studies were carried out on pig thyroid cells cultured (a) without TSH to obtain thyroid cell monolayers (TCM) in basal state or (b) with TSH in the form of cell monolayers (TCM-T) or as reconstituted thyroid follicles (RTF). Iodide uptake activity, thyroperoxidase protein and thyroglobulin mRNA taken as parameters of thyroid cell differentiation were 6 to 25-fold higher in RTF and TCM-T than in TCM. Western blot analyses of Na+ K+ ATPase subunits revealed that the alpha-subunit (105 kDa) content of TCM-T and RTF was similar but 8-fold higher than that of TCM. In contrast, the beta-subunit (50 kDa) content of TCM-T and RTF was only about twice that of TCM. Similar relative variations were observed at the mRNA level for both alpha- and beta-subunits. Na+ K+ ATPase activity was only 40% higher in RTF and TCM-T than in TCM. A 48 h treatment of RTF by either T4 or T3 (1-100 nM) induced a 3-fold increase of the alpha-subunit but did neither alter the beta-subunit nor the Na+ K+ ATPase activity. In conclusion, Na+ K+ ATPase activity and the level of expression of its beta-subunit, known to control the assembly and targetting of alpha-beta oligomers and thus the amount of functional sodium pump at the plasma membrane, are only moderately altered when thyroid cells undergo major changes in their differentiation status. Our data show that the expression of the alpha-subunit of Na+ K+ ATPase by thyroid cells is up-regulated by TSH and thyroid hormones.
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Affiliation(s)
- A Paire
- Institut National de la Santé et de la Recherche Médicale, U369, Faculté de Médecine Lyon-RTH Laënnec, France
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Caillou B, Troalen F, Baudin E, Talbot M, Filetti S, Schlumberger M, Bidart JM. Na+/I- symporter distribution in human thyroid tissues: an immunohistochemical study. J Clin Endocrinol Metab 1998; 83:4102-6. [PMID: 9814499 DOI: 10.1210/jcem.83.11.5262] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Antipeptide antibodies raised against the carboxyl-terminal region of the human sodium/iodide (Na+/I-) symporter (hNIS) were used to investigate by immunohistochemistry the presence and distribution of the hNIS protein in normal thyroid tissues, in some pathological nonneoplastic thyroid tissues, and in different histotypes of thyroid neoplasms. In normal thyroid tissue, staining of hNIS protein was heterogeneous and limited to a minority of follicular cells that were in close contact with capillary vessels. In positive cells, immunostaining was limited to the basolateral membrane. In contrast, in Graves' disease the majority of follicular cells expressed the hNIS protein. In autoimmune thyroiditis, the number of hNIS-positive cells, was similar to that found in normal tissue. These positive cells were found essentially close to lymphocytic infiltrates. This observation supports the concept of hNIS as an autoantigen. In diffuse nodular hyperplasia, hNIS staining was heterogeneous, but the number of hNIS-positive cells exceeded that found in normal tissue. In well differentiated follicular or papillary carcinoma, the number of hNIS-positive cells was significantly lower than in normal tissue. In poorly differentiated follicular carcinoma, the number ofhNIS-positive cells was less than that found in well differentiated carcinoma, or there were no positive cells. Interestingly, in all of these thyroid tissues, the number of follicular cells exhibiting TSH receptor (TSHR) immunoreactivity was greater than the number ofhNIS-positive cells. As hNIS expression appears to be related to TSHR stimulation, the decreased number of TSHR-positive cells in cancers may contribute to the reduced capacity of neoplastic cells to concentrate iodide. In one patient with a follicular cancer with an absence of hNIS immunostaining, the total body 131I scan showed no uptake in metastatic tissue. In three cancers with positive hNIS cells, the 131I scan showed uptake in lymph node metastases. This suggests that immunodetection of hNIS could predict radioiodine uptake in thyroid cancers.
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Affiliation(s)
- B Caillou
- Department of Pathology, Institut Gustave-Roussy, Villejuif, France
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Levy O, De la Vieja A, Ginter CS, Riedel C, Dai G, Carrasco N. N-linked glycosylation of the thyroid Na+/I- symporter (NIS). Implications for its secondary structure model. J Biol Chem 1998; 273:22657-63. [PMID: 9712895 DOI: 10.1074/jbc.273.35.22657] [Citation(s) in RCA: 134] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Na+/I- symporter (NIS), a 618-amino acid membrane glycoprotein that catalyzes the active accumulation of I- into thyroid cells, was identified and characterized at the molecular level in our laboratory (Dai, G., Levy, O., and Carrasco, N. (1996) Nature 379, 458-460). Because mature NIS is highly glycosylated, it migrates in SDS-polyacrylamide gel electrophoresis as a broad polypeptide of higher molecular mass (approximately 90-110 kDa) than nonglycosylated NIS (approximately 50 kDa). Using site-directed mutagenesis, we substituted both separately and simultaneously the asparagine residues in all three putative N-linked glycosylation consensus sequences of NIS with glutamine and assessed the effects of the mutations on function and stability of NIS in COS cells. All mutants were active and displayed 50-90% of wild-type NIS activity, including the completely nonglycosylated triple mutant. This demonstrates that to a considerable extent, function and stability of NIS are preserved in the partial or even total absence of N-linked glycosylation. We also found that Asn225 is glycosylated, thus proving that the hydrophilic loop that contains this amino acid residue faces the extracellular milieu rather than the cytosol as previously suggested. We demonstrated that the NH2 terminus faces extracellularly as well. A new secondary structure model consistent with these findings is proposed.
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Affiliation(s)
- O Levy
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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47
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Abstract
The Na+/I- symporter (NIS) catalyzes the accumulation of iodide into thyroid cells, an essential step in the biosynthesis of thyroid hormones. As a result of the isolation of the rat NIS cDNA, steadfast advances in the study of NIS at the molecular level have resulted in the following accomplishments: generation of high-affinity anti-NIS antibodies, elucidation of NIS stoichiometry and specificity by electrophysiological analysis, biochemical and immunological experimental testing of the proposed NIS secondary structure model, monitoring the regulation of NIS protein expression by thyroid stimulating hormone and iodide, characterization of the rat NIS gene promoter, isolation of the cDNA clone encoding human NIS and subsequent determination of human NIS genomic organization, description of NIS mutations in patients with congenital lack of iodide transport, and the molecular identification of NIS in extrathyroidal tissues.
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Affiliation(s)
- O Levy
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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Saito T, Endo T, Kawaguchi A, Ikeda M, Katoh R, Kawaoi A, Muramatsu A, Onaya T. Increased expression of the sodium/iodide symporter in papillary thyroid carcinomas. J Clin Invest 1998; 101:1296-300. [PMID: 9525971 PMCID: PMC508706 DOI: 10.1172/jci1259] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Iodide is concentrated to a much lesser extent by papillary thyroid carcinoma as compared with the normal gland. The Na+/I- symporter (NIS) is primarily responsible for the uptake of iodide into thyroid cells. Our objective was to compare NIS mRNA and protein expression in papillary carcinomas with those in specimens with normal thyroid. Northern blot analysis revealed a 2.8-fold increase in the level of NIS mRNA in specimens with papillary carcinoma versus specimens with normal thyroid. Immunoblot analysis using anti-human NIS antibody that was produced with a glutathione S-transferase fusion protein containing NIS protein (amino acids 466-522) showed the NIS protein at 77 kD. The NIS protein level was elevated in 7 of 17 cases of papillary carcinoma but was not elevated in the normal thyroid. Immunohistochemical staining revealed abundant NIS in 8 of 12 carcinomas, whereas NIS protein was barely detected in specimens with normal thyroid. Although considerable patient-to-patient variation was observed, our results indicate that NIS mRNA is elevated, and its protein tends to be more abundant, in a subset of papillary thyroid carcinomas than in normal thyroid tissue.
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Affiliation(s)
- T Saito
- Third Department of Internal Medicine, Yamanashi Medical University, Tamaho, Yamanashi 409-38, Japan
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Morris JC. Mutations and disorders involving the thyroid iodide transporter--the next wave in thyroid diseases. J Clin Endocrinol Metab 1997; 82:3964-5. [PMID: 9398696 DOI: 10.1210/jcem.82.12.4474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Schmutzler C, Winzer R, Meissner-Weigl J, Köhrle J. Retinoic acid increases sodium/iodide symporter mRNA levels in human thyroid cancer cell lines and suppresses expression of functional symporter in nontransformed FRTL-5 rat thyroid cells. Biochem Biophys Res Commun 1997; 240:832-8. [PMID: 9398654 DOI: 10.1006/bbrc.1997.7715] [Citation(s) in RCA: 132] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Decreased iodide uptake in de-differentiated thyroid carcinomas impedes radioiodide therapy. RTPCR analysis revealed reduced expression of Na+/I- symporter (NIS) mRNA in human thyroid carcinomas as compared to normal thyroid. However, in follicular thyroid carcinoma cell lines FTC-133 and FTC-238, treatment with 1 microM all-trans retinoic acid (RA) markedly increased NIS mRNA levels. Anaplastic thyroid carcinoma cell lines HTh74 and C643 showed basal expression of NIS mRNA, but no RA-stimulation. All four cell lines contained the approximately 80 kD NIS protein as judged by Western blot, although they did not accumulate iodide. In contrast, in nontransformed rat FRTL-5 cells, 1 microM RA downregulated NIS mRNA levels, inhibited the TSH- or forskolin-triggered induction of NIS message after TSH-depletion, and reduced iodide uptake to 38% after 5 d. This divergent RA-responsivity of NIS may provide the means to target radioiodide to thyroid carcinomas by upregulating iodide transport into tumor tissue while simultaneously inhibiting iodide accumulation in normal thyrocytes and may thus re-establish the potential for radioiodide therapy.
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Affiliation(s)
- C Schmutzler
- Medizinische Poliklinik, Universität, Würzburg, Germany.
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