Expression of sodium iodide symporter in benign and malignant human thyroid tissues

The extent of human sodium iodide symporter (hNIS) expression in different kinds of human thyroid cancer tissues and cell lines remains controversial. In this study, polyclonal antibodies to hNIS were used to analyze the expression of symporter protein in benign and malignant human thyroid tissues. Formalin-fixed, paraffin wax-embedded tissue sections were used. Staining was performed using primary polyclonal antibody of rabbit anti-human hNIS diluted in PBS (1:500). Results showed that 2 of 3 normal tissue, 3 of nodular hyperplasia, one follicular adenoma, 3 of 11 papillary thyroid carcinoma, 1 of 5 follicular carcinoma and none of 3 metastatic thyroid epithelial tissue specimens stained positively for hNIS. A higher percentage of positive staining for symporter protein was found in benign thyroid tissues including normal thyroid tissue, nodular hyperplasia, and adenoma (60%). In contrast, papillary and follicular thyroid carcinomas demonstrated lower symporter protein expression (20%). In conclusion, although the number of tissue samples examined in this study was small, hNIS staining found a higher ratio of symporter protein expression in normal and benign thyroid tissues compared with malignant tissues. Determination of the reason for discrepancies in the expression of hNIS in in vivo and in vitro studies will require further investigation.     

Expression of the sodium iodide symporter and thyroglobulin genes are reduced in papillary thyroid cancer.

Altered expression of the gene encoding the sodium iodine symporter (NIS) may be an important factor that leads to the reduced iodine accumulation characteristic of most benign and malignant thyroid nodules. Both up- and down-regulation of NIS gene expression have been reported in thyroid cancer using several different methods. The goal of the present study was to accurately identify alterations in NIS gene expression in benign and malignant thyroid nodules using an accurate real-time quantitative RT-PCR assay system. Total RNA was prepared from 18 benign thyroid nodules, 20 papillary thyroid cancers, and 23 normal thyroid samples from 38 subjects. Quantitative RT-PCR was used to measure NIS and thyroglobulin (TG) mRNA expression in normal thyroid tissue and in each nodular tissue sample. Papillary thyroid cancer samples had significantly lower NIS mRNA expression (72 +/- 41 picogram equivalents [pg Eq]), than did benign nodules (829 +/- 385 pg Eq), or normal tissues (1907 +/- 868 pg Eq, P = 0.04). Most important, in the paired samples, NIS gene expression was decreased in each papillary thyroid cancer compared with normal tissue (69% median decrease; range, 40-96%; P = .013). Eleven of the 12 benign nodules also demonstrated lower NIS gene expression than the normal tissue (49% decrease; range, 2-96%; P = .04). Analysis of the paired samples demonstrated that Tg mRNA expression was significantly lower in each of the thyroid cancer samples than in corresponding normal tissue (759 +/- 245 pg Eq vs. 1854 +/- 542 pg Eq, P = .03). We have demonstrated a significant decrement in NIS gene expression in all papillary thyroid cancers and in over 90% of benign nodules examined compared with adjacent normal thyroid tissue, using a highly accurate quantitative RT-PCR technique. Similarly, thyroid cancers demonstrated significantly lower TG mRNA expression than corresponding normal thyroid. Reduced NIS expression may be an important factor in the impairment of iodine-concentrating ability of neoplastic thyroid tissues.     

The correlation of sodium iodide symporter and BRAFV600E mutation in classical variant papillary thyroid carcinoma

BRAF^V600E mutation was analyzed by real-time polymerase chain reaction in 96 consecutive cases with classical variant papillary thyroid cancer, and immunohistochemical staining of Na +/I − symporter (NIS) protein was evaluated. Localization (intracellular or membranous), density, and the intensity of cytoplasmic staining were characterized semiquantitatively. Extrathyroidal invasion, surgical margin positivity, and lymph node metastasis were compared with BRAF^V600E mutation and NIS expression. Eighty-eight patients who had at least 24-month follow-up were also included in survival analysis. BRAF^V600E mutation was determined in 78.1% (75/96) and functional NIS activity in 74% (71/96) of the cases. There were statistically significant differences in mean ages between BRAF^V600E mutation–positive (48.6) and BRAF^V600E mutation–negative cases (37.3; Levene test, P = .419; Student t test, P = .001). The surgical margin positivity (46.7%) and extrathyroidal extension percentage (54.7%) in the BRAF^V600E mutation–positive group were higher than the negative (28.6% and 33.3%, respectively) group, without statistical significance (P = .138 and P = .084, respectively). Functional NIS activity was higher in BRAF^V600E mutation–positive cases (78.1%) than mutation-negative ones (57.1%; P = .047). The possibility of moderate and intense cytoplasmic staining in BRAF^V600E mutation–positive cases (72%) was 6.3 times higher than the possibility of weak staining (28%) in the mutation-positive cases (95% confidence interval, 2.2-18.8; P = .001). Functional NIS expression is higher in patients with classical variant papillary thyroid cancer with BRAF^V600E mutation. However, the clinical features were not found to be associated with NIS expression. There may be different mechanisms determining the outcome of therapy.     

Sodium/iodide symporter: physiopathological aspects and therapeutic perspectives

The existence of the natriuric/iodide symporter (NIS) represents a new view to understand the thyroid metabolism of iodide. Due to its cellular localisation on basolateral membrane, this transporter exerts an essential role in the biological functions of the thyroid, especially the capacity to accumulate iodide into the thyrocytes. Clinical perspectives of NIS activity modulation would ameliorate the diagnosis and the treatment of thyroid diseases by using radioisotopes transported by the NIS (131 iodide, 99m technetium, 188 rhenium). The study of the regulation pathways modulating the expression and the activity of the symporter NIS, would allow to understand pathogeny of benign or malignant diseases of the thyroid gland. The relative facility of the therapy management by 131 iodide and its good efficiency associated to the recent advance of NIS function also give an interesting perspective to the gene therapy treatment of the nonthyroid cancers despite existent methodological problems.     

hTPO和hNIS共转染提高人胶质瘤、肺癌及甲状腺癌细胞摄放射性碘能力

目的 研究共转染人甲状腺过氧化物酶基因（hTPO）及人钠碘转运体基因（hNIS）后胶质瘤、肺癌及甲状腺癌细胞的摄碘能力变化。方法 克隆,重组,包装并扩增纯化得到重组腺病毒（AdTPO）,测定病毒滴度。使用脂质体转染法将hNIS基因转染入人胶质瘤、肺癌及甲状腺癌细胞系中,经过G418抗生素筛选获得稳定表达hNIS的细胞系,只转染hNIS基因的细胞系为对照组;使用重组腺病毒将hTPO基因转导入对照组中,共转染hNIS及hTPO基因的细胞系为实验组;未转入hTPO和hNIS基因的原始肿瘤细胞系为空白对照组。然后进行3组细胞系的体外摄125I 率及各细胞系的125I外流实验。结果 在各肿瘤细胞系中,实验组细胞的摄碘率和有效半衰期,较对照组细胞和空白对照组细胞均有所提高,实验组细胞的摄碘率：H460组为59628 1281,U251组为7968 1261,ARO组为52971 2162,FRO组为49638 1281,三组间总体具有统计学差异（P<0.01）。结论 将hTPO和hNIS基因共转染至肿瘤后,能有效提高肿瘤的摄碘能力并延长细胞内碘滞留时间。     

Sodium/iodide‐symporter: distribution in different mammals and role in entero‐thyroid circulation of iodide

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.     

Mesenchymal Stem Cell-mediated delivery of the sodium iodide symporter supports radionuclide imaging and treatment of breast cancer

Mesenchymal Stem Cells (MSCs) migrate specifically to tumors in vivo, and coupled with their capacity to bypass immune surveillance, are attractive vehicles for tumor-targeted delivery of therapeutic agents. This study aimed to introduce MSC-mediated expression of the sodium iodide symporter (NIS) for imaging and therapy of breast cancer. Tumor bearing animals received an intravenous or intratumoral injection of NIS expressing MSCs (MSC-NIS), followed by (99m) Technetium pertechnetate imaging 3-14 days later using a BazookaSPECT γ-camera. Tissue was harvested for analysis of human NIS (hNIS) expression by relative quantitative-polymerase chain reaction. Therapy animals received an i.p. injection of (131) I or saline 14 days after injection of MSC-NIS, and tumor volume was monitored for 8 weeks. After injection of MSC-NIS, BazookaSPECT imaging revealed an image of animal intestines and chest area at day 3, along with a visible weak tumor image. By day 14, the tumor was visible with a significant reduction in radionuclide accumulation in nontarget tissue observed. hNIS gene expression was detected in the intestines, heart, lungs, and tumors at early time points but later depleted in nontarget tissues and persisted at the tumor site. Based on imaging/biodistribution data, animals received a therapeutic dose of (131) I 14 days after MSC-NIS injection. This resulted in a significant reduction in tumor growth (mean ± SEM, 236 ± 62 mm(3) vs. 665 ± 204 mm(3) in controls). The ability to track MSC migration and transgene expression noninvasively in real time before therapy is a major advantage to this strategy. This promising data supports the feasibility of this approach as a novel therapy for breast cancer.     

靶向性启动子携带报告基因NIS介导提高胶质瘤摄碘能力

目的 在细胞实验中探讨靶向性人端粒酶逆转录酶(hTERT)启动子携带人类钠碘转运体(hNIS)基因能否提高胶质瘤的摄碘能力.方法 检测在hTERT启动子引导下表达hNIS基因的腺病毒,使用该腺病毒转染U87和U251细胞系,然后使用Υ记数仪检测转染后细胞的摄碘能力.结果 实验组肿瘤细胞在转染Ad-hTERT-hNIS后...     

A transporter gene (sodium iodide symporter) for dual purposes in gene therapy: imaging and therapy

Radioiodide uptake (RAIU) in thyroid follicular epithelial cells, mediated by a plasma membrane transporter, sodium iodide symporter (NIS), provides a first step mechanism for thyroid cancer detection by radioiodide injection and effective radioiodide treatment for patients with invasive, recurrent, and/or metastatic thyroid cancers after total thyroidectomy. NIS gene transfer to tumor cells may significantly and specifically enhance internal radioactive accumulation of tumors following radioiodide administration, and result in better tumor control. NIS gene transfers have been successfully performed in a variety of tumor animal models by either plasmid-mediated transfection or virus (adenovirus or retrovirus)-mediated gene delivery. These animal models include nude mice xenografted with human melanoma, glioma, breast cancer or prostate cancer, rats with subcutaneous thyroid tumor implantation, as well as the rat intracranial glioma model. In these animal models, non-invasive imaging of in vivo tumors by gamma camera scintigraphy after radioiodide or technetium injection has been performed successfully, suggesting that the NIS can serve as an imaging reporter gene for gene therapy trials. In addition, the tumor killing effects of 131I after NIS gene transfer have been demonstrated in in vitro clonogenic assays and in vivo radioiodide therapy studies, suggesting that NIS gene can also serve as a therapeutic agent when combined with radioiodide injection. Better NIS-mediated tumor treatment by radioiodide requires a more efficient and specific system of gene delivery with better retention of radioiodide in tumor. Results thus far are, however, promising, and suggest that NIS gene transfer followed by radioiodide treatment will allow non-invasive in vivo imaging to assess the outcome of gene therapy and provide a therapeutic strategy for a variety of human cancers.     

钠碘转运体基因显像及治疗新进展

钠碘转运体（NIS）是一种位于甲状腺滤泡细胞膜上的糖蛋白，负责介导碘进入甲状腺滤泡细胞内。因为NIS的运碘特性，所以临床上有巨大的应用价值。目前，NIS基因可以作为报告基因进行显像，还可以通过NIS基因介导放射性核素治疗癌症。但是将这种方法应用于临床还面临很多问题，细胞中碘的有效半衰期较短就是其中之一。对此，已有的解决方法，一是，使用NIS介导更强的放射性核索；再是，进行甲状腺过氧化物酶基因（TPO）的共转染。     

The sodium iodide symporter (NIS) as an imaging reporter for gene, viral, and cell-based therapies

Preclinical and clinical tomographic imaging systems increasingly are being utilized for non-invasive imaging of reporter gene products to reveal the distribution of molecular therapeutics within living subjects. Reporter gene and probe combinations can be employed to monitor vectors for gene, viral, and cell-based therapies. There are several reporter systems available; however, those employing radionuclides for positron emission tomography (PET) or singlephoton emission computed tomography (SPECT) offer the highest sensitivity and the greatest promise for deep tissue imaging in humans. Within the category of radionuclide reporters, the thyroidal sodium iodide symporter (NIS) has emerged as one of the most promising for preclinical and translational research. NIS has been incorporated into a remarkable variety of viral and non-viral vectors in which its functionality is conveniently determined by in vitro iodide uptake assays prior to live animal imaging. This review on the NIS reporter will focus on 1) differences between endogenous NIS and heterologously-expressed NIS, 2) qualitative or comparative use of NIS as an imaging reporter in preclinical and translational gene therapy, oncolytic viral therapy, and cell trafficking research, and 3) use of NIS as an absolute quantitative reporter.     

Metabolic syndrome: pathophysiology and impact on lithogenesis

In our societies, the increase of the frequency of the diseases of overweight, in particular obesity, diabetes type 2 and metabolic syndrome, coincides with that of the urinary lithiasis. Like the lithiasic disease, the metabolic syndrome or syndrome X is multi-factor. Several epidemiological studies were interested in research of a physiopathological relation between the various components of this syndrome (obesity, arterial hypertension, diabetes, dyslipemy) and lithogenesis. During the metabolic syndrome, resistance to insulin and the defect of renal ammoniogenesis constitute the principal disorders supporting lithogenesis. The defect of renal ammoniogenesis armature by the resistance of the renal cells to insulin involves a urinary hyperacidity which supports the crystallization of the uric acid responsible for the formation of uric or mixed uric acid/oxalate stones.     

Sodium/iodide symporter expression in primary lung cancer and comparison with glucose transporter 1 expression

The aim of the present study was to evaluate the expression of sodium/iodide symporter (NIS) and glucose transporter 1 (Glut1) in 139 primary lung cancers on immunohistochemistry, and to determine the diagnostic utility of NIS as an imaging reporter. Immunoreactivity for NIS and Glut1 was noted in 75 (54.0%) and 72 (51.8%) of the 139 cases, respectively. Analysis of NIS expression on Western blot confirmed the immunohistochemistry. NIS expression was significantly higher in the adenocarcinomas than in the other carcinomas, and Glut1 expression was significantly higher in the squamous cell carcinomas than in the other carcinomas (each P  < 0.0001). The frequency of NIS expression in those carcinomas lacking Glut1 expression was significantly higher than in those with Glut1 expression ( P  = 0.012). Among 64 adenocarcinomas, the frequency of the NIS(+)/Glut1(−) phenotype was 61.0%, which was the most frequent expression pattern. By studying the expression pattern of NIS in lung cancer, the present paper provides a helpful foundation for examining the potential utility of NIS-mediated radioiodide as an alternative diagnostic modality, especially for the management of patients with lung adenocarcinoma lacking Glut1 expression.     

Kinetic analysis of iodide transport in dog thyroid slices: perchlorate-induced discharge.

Dog thyroid slices were incubated with methimazole (2 mM) and radioiodide. The medium radioactivity was continuously recorded for 8 h. Multiple data were collected for individual glands to calculate simultaneously by compartmental analysis the influx and efflux rates of iodide from the slices. A two-compartment thyroid model was necessary and sufficient to simulate the transport of inorganic iodide. The two compartments could be defined as the cellular and the luminal spaces, but interferences due to slice thickness, nonuniform follicle sizes, and open follicles were not excluded. Sodium perchlorate (1 mM) inhibited the influx of iodide into the follicles and discharged the trapped radioiode into the medium with increased efflux rates. Our data suggest that perchlorate decreases the inward influx rates by competition and enhances the outward efflux rates by countertransport and support the hypothesis of mobile iodide carriers at the basal and apical membranes of the thyroid cells.     

Effect of potassium iodide and perchlorate on the secretion of thyroid hormones

The effect of potassium iodide and perchlorate was studied on parameters characterizing the secretion of thyroid hormones: the cyclic AMP level in the thyroid gland tissue and the number of intracellular colloid drops during stimulation with thyroid hormones. Excess of iodide was shown to depress these indices whereas perchlorate prevented the inhibitory effect of iodide. The results support the view that the adenylate-cyclase system of the thyroid gland is sensitive to the organic iodine concentration. Excess of iodide evidently reduces the ability of perchlorate to affect its concentration in the gland, so that the process of organification of iodine and the secretion of thyroid hormones are maintained at the optimal level.Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 86, No. 12, pp. 653–655, December, 1978.     

MicroRNAs in gray and white matter multiple sclerosis lesions: impact on pathophysiology

Multiple sclerosis (MS) is a chronic disease of the CNS, hallmarked by inflammation and demyelination. Early stages of the disease frequently show active lesions containing numerous foamy macrophages and inflammatory cells. Disease progression is highlighted by increasing numbers of mixed active/inactive or inactive lesions showing sparse inflammation and pronounced astrogliosis. Furthermore, gray matter lesions increase in number and extent during disease progression. MicroRNAs (miRNAs) comprise a group of several thousand (in humans more than 2000), small non-coding RNA molecules with a fundamental influence on about one-third of all protein-coding genes. Furthermore, miRNAs have been detected in body fluids, including spinal fluid, and they are assumed to participate in intercellular communications. Several studies have determined miRNA profiles from dissected white and gray matter lesions of autoptic MS patients. In this review, we summarize in detail the current knowledge of individual miRNAs in gray and white matter lesions of MS patients and present the concepts of MS tissue lesion development based on the altered miRNA profiles. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.