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FILETTI
Regulation of iodide uptake and sodium/iodide symporter expression in the MCF-7 human breast cancer cell line.Arturi F, Ferretti E, Presta I, Mattei T, Scipioni A, Scarpelli D, Bruno R, Lacroix L, Tosi E, Gulino A, Russo D, Filetti S. J Clin Endocrinol Metab. 2005 Apr;90(4):2321-6. Epub 2004 Dec 28.
"Sodium/iodide symporter (NIS) expression has recently been described in human breast cancer, with emphasis on its potential exploitation for the treatment of these tumors with radioiodine. In this study, we analyzed the regulation of NIS expression and function in the MCF-7 human breast cancer cell line. Cell exposure to insulin, IGF-I, IGF-II, or prolactin induced significant increases in 125I uptake and the expression of both NIS mRNA and NIS protein. The latter increases were evident after 6 and 12 h of hormonal stimulation, respectively. In immunocytochemistry studies, NIS was detected mainly in the plasma membrane of MCF-7 cells. A low but significant increase in iodide uptake was produced by treatment with activators of the adenylyl cyclase (cAMP) or protein kinase C pathways.
Our study demonstrates that: 1) MCF-7 breast cancer cells are capable of active iodide transport that can be stimulated by insulin, IGF-I, IGF-II, or prolactin; 2) both NIS transcript and protein are expressed in these cells, and this expression is also hormonally stimulated; and 3) MCF-7 iodide transport and NIS expression may be influenced by the activation of cAMP or protein kinase C-dependent signaling. These findings increase our understanding of the molecular mechanisms that regulate NIS expression in breast cancer cells, information that is fundamental for future research aimed at the development of targeted radioiodide treatment for this type of cancer."
Modulation of thyroid-specific gene expression in normal and nodular human thyroid tissues from adults: an in vivo effect of thyrotropin.Bruno R, Ferretti E, Tosi E, Arturi F, Giannasio P, Mattei T, Scipioni A, Presta I, Morisi R, Gulino A, Filetti S, Russo D. J Clin Endocrinol Metab. 2005 Oct;90(10):5692-7. Epub 2005 Aug 2.
"CONTEXT: Evidence from in vitro studies or animal models has shown that TSH affects thyrocytes by thyroid-specific expression modulation.
OBJECTIVE: The objective of our study was to analyze the role of TSH in human thyroid gene expression in vivo.
DESIGN/SETTING: Thirty-nine normal thyroid tissues were collected at the same center.
STUDY SUBJECTS: Patients were divided into two groups based on serum TSH levels: 17 with normal TSH levels (1-4 mU/liter; group 1) and 22 with TSH levels below 0.5 mU/liter (group 2).
INTERVENTION: Group 2 underwent thyroidectomy after suppressive L-T4 therapy.
MAIN OUTCOME MEASURES: mRNA levels of thyroid genes such as sodium/iodide symporter (NIS), apical iodide transporter, pendrin, thyroglobulin, thyroperoxidase, TSH receptor, paired box transcription factor 8, and thyroid transcription factor-1 were evaluated by quantitative PCR.
RESULTS: The reduction of TSH stimulation causes decreases in NIS and apical iodide transporter gene expression in normal tissues and more limited reductions in thyroglobulin, thyroperoxidase, and paired box transcription factor 8, but it has no significant effect on TSH receptor, pendrin, or thyroid transcription factor-1. Comparison of NIS levels in normal and nodular tissues from the same patient confirmed that it is differentially expressed in nodules only in the presence of normal TSH (P < 0.01). In patients with suppressed TSH, nodular NIS levels were similar to those in normal tissues.
CONCLUSIONS: Our data represent the first demonstration in human thyroid tissues that TSH contributes to the regulation of thyrocyte differentiation by modulating thyroid gene levels. It exerts a particularly important effect on the transcription of NIS, which becomes very low after prolonged TSH suppression."
Recovery of NIS expression in thyroid cancer cells by overexpression of Pax8 gene.Presta I, Arturi F, Ferretti E, Mattei T, Scarpelli D, Tosi E, Scipioni A, Celano M, Gulino A, Filetti S, Russo D. BMC Cancer. 2005 Jul 19;5(1):80.
"BACKGROUND: Recovery of iodide uptake in thyroid cancer cells by means of obtaining the functional expression of the sodium/iodide symporter (NIS) represents an innovative strategy for the treatment of poorly differentiated thyroid cancer. However, the NIS gene expression alone is not always sufficient to restore radioiodine concentration ability in these tumour cells.
METHODS: In this study, the anaplastic thyroid carcinoma ARO cells were stably transfected with a Pax8 gene expression vector. A quantitative RT-PCR was performed to assess the thyroid specific gene expression in selected clones. The presence of NIS protein was detected by Western blot and localized by immunofluorescence. A iodide uptake assay was also performed to verify the functional effect of NIS induction and differentiation switch.
RESULTS: The clones overexpressing Pax8 showed the re-activation of several thyroid specific genes including NIS, Pendrin, Thyroglobulin, TPO and TTF1. In ARO-Pax8 clones NIS protein was also localized both in cell cytoplasm and membrane. Thus, the ability to uptake the radioiodine was partially restored, associated to a high rate of efflux. In addition, ARO cells expressing Pax8 presented a lower rate of cell growth.
CONCLUSION: These finding demonstrate that induction of Pax8 expression may determine a re-differentiation of thyroid cancer cells, including a partial recovery of iodide uptake, fundamental requisite for a radioiodine-based therapeutic approach for thyroid tumours."
Expression, regulation, and function of paired-box gene 8 in the human placenta and placental cancer cell lines.Ferretti E, Arturi F, Mattei T, Scipioni A, Tell G, Tosi E, Presta I, Morisi R, Lacroix L, Gulino A, Russo D, Damante G, Filetti S. Endocrinology. 2005 Sep;146(9):4009-15. Epub 2005 Jun 16.
"Pax proteins are transcriptional regulators that control a variety of developmental decisions in vertebrates. During development, the paired-box gene 8 (PAX8) is expressed in the thyroid, kidney, and several areas of the central nervous system. It is also expressed in the adult thyroid gland, in which it mediates TSH-induced modulation of the expression of important genes, such as those encoding thyroglobulin, thyroperoxidase, and the sodium/iodide symporter (NIS). Thus far, placental expression of PAX8 has been described only in mice. In the present study, we show that PAX8 is also expressed in the human placenta at term. In an in vitro model of placental cancer, the JAR choriocarcinoma cell line, human chorionic gonadotropin (hCG) increased levels of PAX8 mRNA and protein, and gel retardation assays indicated that the up-regulation of PAX8 protein expression is associated with an increase in its DNA-binding activity. The effects of hCG were mimicked by forskolin, indicating that they are cAMP dependent. Levels of mRNA for the Wilms' tumor 1 (WT1) and NIS genes were increased in JAR cells by hCG treatment, whereas overexpression of PAX8 increased only levels of WT1 mRNA. In cells transfected with PAX8-specific small interfering RNA, the stimulatory effects of hCG on WT1 mRNA levels were abolished, but hormonal enhancement of NIS mRNA levels was unchanged. These findings indicate that, in JAR cells, hCG activates a cAMP-dependent pathway that can up-regulate WT1 expression through PAX8."
Sodium iodide symporter expression and radioiodine distribution in extrathyroidal tissues.Bruno R, Giannasio P, Ronga G, Baudin E, Travagli JP, Russo D, Filetti S, Schlumberger M. J Endocrinol Invest. 2004 Dec;27(11):1010-4. [abstract only]
"The functional role of the sodium iodide symporter (NIS) in extrathyroidal tissues was investigated by examining its mRNA and protein expression, together with the evidence of radioiodine (131)I uptake in 302 patients who underwent (131)I total body scanning, following the administration of high doses of (131)I for a papillary or follicular thyroid carcinoma. By using a real-time kinetic quantitative RT-PCR and immunohistochemistry, the expression of NIS protein was detected mainly in secretory tissues. In parallel, 1311 uptake was evidenced in the majority of patients in the salivary glands (in 39%) and stomach (in 78%), but was found in breast in only 4 young female patients. These data demonstrate a strong correlation between the organ radioactivity distribution, as observed in vivo, and NIS protein expression. Interestingly, (131)I is rarely concentrated by mammary glands, even when large doses are administered. Moreover, a (131)I transfer in secretion fluids may represent a potential source of contamination responsible for false positive images and diagnostic pitfalls."
Transcriptional regulation of human sodium/iodide symporter gene: a role for redox factor-1.Puppin C, Arturi F, Ferretti E, Russo D, Sacco R, Tell G, Damante G, Filetti S. Endocrinology. 2004 Mar;145(3):1290-3. Epub 2003 Nov
20. "The transcriptional regulation of the human sodium/iodide symporter (NIS) gene in normal and transformed thyroid cells is a crucial issue in attempting to restore iodide uptake and use radioiodine as a therapeutic treatment of thyroid cancer. Previous investigations have shown that the multifunctional protein apurinic apyrimidinic endonuclease/redox factor 1 (APE/Ref-1) plays an important role in regulation of thyroid-specific gene transcription.
In this study, we investigated the effects of APE/Ref-1 on human NIS promoter activity. Cotransfection experiments performed in nonthyroid HeLa cells demonstrated that APE/Ref-1 exerts both PAX8-dependent and PAX8-independent effects. In fact, in the absence of PAX8, overexpression of APE/Ref-1 enhanced NIS promoter activity 2-fold. When the expression plasmid of APE/Ref-1 was transfected together with an expression plasmid for PAX8, a strong cooperative effect was detected with an increase of NIS promoter activity 9-fold over control. The PAX8-independent effect of APE/Ref-1 was specific for the NIS promoter, resulting not present for the promoter of the thyroperoxidase (TPO) gene. It was, at least in part, due to the up-regulation of the transcriptional activity of the ubiquitous factor early growth response-1 (Egr-1). In the thyroid tumor cell lines TPC-1 and B-CPAP, APE/Ref-1 was not effective by itself, and it also failed to increase PAX8 stimulation on NIS promoter activity.
These data demonstrate a role for APE/Ref-1 protein in the transcriptional regulation of NIS gene expression by itself and in cooperation with PAX8. However, restoring the PAX8-APE/Ref-1 expression in tumor cells may not be sufficient to obtain adequate levels of NIS gene expression."
Increased expression of AP2 and Sp1 transcription factors in human thyroid tumors: a role in NIS expression regulation?Chiefari E, Brunetti A, Arturi F, Bidart JM, Russo D, Schlumberger M, Filetti S. BMC Cancer. 2002 Dec 10;2:35. Epub 2002 Dec 10.
"BACKGROUND: Sodium/iodide symporter (NIS) is a key protein in iodide transport by thyroid cells and this activity is a prerequisite for effective radioiodide treatment of thyroid cancer. In the majority of thyroid cancers, however, iodide uptake is reduced, probably as a result of decreased NIS protein expression.
METHODS: To identify the mechanisms that negatively affect NIS expression in thyroid tumors, we performed electrophoresis mobility shift assays and immunoblot analysis of nuclear protein extracts from normal and tumoral thyroid tissues from 14 unrelated patients.
RESULTS: Two proteins closely related to the transcription factors AP2 and Sp1 were identified in the nuclear extracts. Expression of both AP2 and Sp1 in nuclear extracts from thyroid tumors was significantly higher than that observed in corresponding normal tissues.
CONCLUSION: These observations raise the possibility that NIS expression, and subsequently iodide transport, are reduced in thyroid tumors at least in part owing to alterations in the binding activity of AP2 and Sp1 transcription factors to NIS promoter.
Stimulation of iodide uptake by human chorionic gonadotropin in FRTL-5 cells: effects on sodium/iodide symporter gene and protein expression.Arturi F, Presta I, Scarpelli D, Bidart JM, Schlumberger M, Filetti S, Russo D. Eur J Endocrinol. 2002 Nov;147(5):655-61.
"BACKGROUND: Various clinical and experimental findings support the concept that human chorionic gonadotropin (hCG) can stimulate iodide uptake in thyroid cells.
DESIGN: We investigated the molecular mechanisms underlying the effects of hCG on iodide uptake, and particularly its action on the expression of Na+/I- symporter (NIS) mRNA and protein.
METHODS: Iodide uptake was analyzed in FTRL-5 cells by measuring (125)I concentrations in cells after a 30-min exposure to 0.1 microCi carrier-free Na (125)I in the presence or absence of hCG or, for control purposes, TSH. Expression of NIS mRNA and NIS protein synthesis were evaluated, respectively, with a semiquantitative 'multiplex' RT-PCR method and Western blot analysis.
RESULTS: Iodide uptake was increased by hCG in a dose- and time-dependent manner: maximal effects were observed after 72 h of stimulation. The effect was cAMP dependent and paralleled that of TSH, although it lacked the early cycloheximide-independent component seen with TSH, and its peak effect was lower. Semiquantitative multiplex RT-PCR revealed that hCG produced a significant increase in NIS mRNA levels that was detectable after 4 h and peaked after 48 h. In contrast, in TSH-stimulated FRTL-5 cells, maximum NIS mRNA expression was observed after 24 h of stimulation. Western blot analysis demonstrated that hCG also caused a 2.5-fold increase over basal values in NIS protein levels, which was similar to that observed after TSH stimulation although the peak effects of the latter hormone were less marked and occurred earlier.
CONCLUSION: Our data demonstrated that hCG stimulates iodide uptake in FRTL-5 cells by increasing NIS mRNA and protein levels. Thus, the functional status of the thyroid may be influenced by hCG-dependent changes in NIS expression occurring during pregnancy."
Regulation by human chorionic gonadotropin of sodium/iodide symporter gene expression in the JAr human choriocarcinoma cell line.Arturi F, Lacroix L, Presta I, Scarpelli D, Caillou B, Schlumberger M, Russo D, Bidart JM, Filetti S. Endocrinology. 2002 Jun;143(6):2216-20.
"Sodium/iodide symporter (NIS) gene and protein
expressions have been recently described in human cytotrophoblasts,
emphasizing its potential function in the active transport of iodide
from the mother to the fetus. In this study we analyzed NIS expression
and function in the human JAr placental choriocarcinoma cell line.
Using real-time quantitative RT-PCR, we first demonstrated that NIS
transcripts are expressed at a high level in JAr cells compared with
other cell lines, including thyroid cancer cells. Functional analysis
clearly showed that Jar cells are able to concentrate iodide in
presence of hCG. Iodide accumulation increased after 2-h exposure to 5
IU/ml hCG, to 6-fold over the basal level after 8 h. This effect was
reproduced using forskolin, the cAMP analog (Bu)(2)-cAMP, and phorbol
acetate. Moreover, hCG increased both NIS mRNA after 2 h and NIS
protein levels after 4 h, reaching a maximum after 8 h in both cases.
In conclusion, our data demonstrate that 1) NIS is expressed in JAr
cells; 2) iodide transport in JAr cells is regulated by hCG and by
cAMP-dependent and -independent mechanisms; 3) the stimulation of
iodide uptake is due to an increase in both NIS mRNA and protein
levels; and 4) JAr cells may represent an excellent in vitro model
suitable to analyze the molecular mechanisms involved in iodide
transport from mother to fetus."
Transposition of the thyroid iodide uptake and organification system in nonthyroid tumor cells by adenoviral vector-mediated gene transfers.Boland A, Magnon C, Filetti S, Bidart JM, Schlumberger M, Yeh P, Perricaudet M. Thyroid. 2002 Jan;12(1):19-26. [abstract only]
"Radioactive iodine (131I) is routinely used for the treatment of differentiated thyroid cancers. Attempts have been made to enlarge this therapeutic strategy to nonthyroid tumors by coupling radioactive iodide administration with transfer of the sodium iodide symporter (NIS) gene into target cells, for example with an adenoviral vector (AdNIS). Although efficient iodide uptake was achieved in the tumors treated with AdNIS, no therapeutic effect could be observed with 131I, most probably because the iodide retention time in the target cells was short. To circumvent this problem, we propose to organify the iodide taken up, as it occurs in the thyroid. We constructed a recombinant adenovirus encoding the human thyroperoxidase (TPO) gene under the control of the cytomegalovirus early promoter (AdTPO). Infection of nonthyroid tumor cells with this virus led to production of an enzymatically active protein. A significant increase in iodide organification could be observed in cells coinfected with both AdNIS and AdTPO in the presence of exogenous hydrogen peroxide. However, the levels of iodide organification obtained were too low to significantly increase the iodide retention time in the target cells."
Sodium/iodide symporter (NIS) and pendrin are expressed differently in hot and cold nodules of thyroid toxic multinodular goiter.Russo D, Bulotta S, Bruno R, Arturi F, Giannasio P, Derwahl M, Bidart JM, Schlumberger M, Filetti S. Eur J Endocrinol. 2001 Nov;145(5):591-7.
"OBJECTIVE: The expression of two iodide transporters, the sodium/iodide symporter (NIS) and pendrin, was analyzed in thyroid tissues of patients with toxic multinodular goiter (TMNG) and non-toxic multinodular goiter (MNG).
METHODS: The levels of NIS and pendrin proteins were analyzed in total protein extracts from nodular and non-nodular tissues by Western blot.
RESULTS: In tissue samples from TMNG, we found an increased expression of NIS (2.5-fold) in the hot nodules, and similar levels between cold nodules and non-nodular tissues. In contrast, the levels of pendrin were slightly increased in both hot and cold nodules from TMNG, and decreased (about twofold) in cold nodules from MNG. We also noticed that there was no relationship between NIS and pendrin expression.
CONCLUSIONS: Our data demonstrate that hot nodules from TMNG express a higher number of iodide transporters (mainly NIS), whereas cold nodules from TMNG, but not from MNG, show levels of the two proteins comparable with normal tissue, suggesting a role in vivo of TSH in maintaining the expression of NIS and pendrin protein in normal thyroid tissue. Finally, different mechanisms are involved in the regulation of NIS and pendrin expression."
Expression pattern of the pendrin and sodium/iodide symporter genes in human thyroid carcinoma cell lines and human thyroid tumors.Arturi F, Russo D, Bidart JM, Scarpelli D, Schlumberger M, Filetti S. Eur J Endocrinol. 2001 Aug;145(2):129-35.
"OBJECTIVE: In the present study we analyzed the pattern of pendrin (PDS) and sodium/iodide symporter (NIS) gene expression in some thyroid carcinoma cell lines and a series of thyroid tumoral tissues.
METHODS: Total RNA was extracted from all cell lines and from 53 tissues, and gene expression was examined by RT-PCR. Semiquantitative 'multiplex' RT-PCR was used to assess variations in PDS gene expression among various thyroid pathologies. Pendrin expression was determined in the thyroid cell lines by Western blot analysis.
RESULTS: PDS mRNA was expressed in all the cells investigated; conversely, NIS mRNA was detectable only in the B-CPAP cells. Pendrin protein was expressed in B-CPAP and WRO cell lines, reduced in FRO and absent in ARO cells. PDS gene expression was not detected in 5 of 25 differentiated thyroid carcinomas (DTC) while NIS gene was not expressed in six carcinomas. A concordance expression of both PDS and NIS transcripts was found in 20 DTC. In contrast, 2 neoplastic thyroid tissues carrying undetectable PDS mRNA maintained NIS transcript, and 3 thyroid carcinomas negative for NIS mRNA retained the expression of PDS gene. A semiquantitative analysis showed that the mean PDS mRNA levels were significantly decreased in DTC tissues.
CONCLUSIONS: Our data demonstrate that
pendrin expression: (i) is present in the more differentiated
thyroid carcinoma cell lines studied; (ii) is reduced or absent
in DTC tissues; (iii) may not correlate with the NIS expression.
These alterations may contribute to the loss of iodine
concentration ability detected in thyroid tumors."
Sodium/iodide symporter in thyroid cancer.Mian C, Lacroix L, Bidart JM, Caillou B, Filetti S, Schlumberger M. Exp Clin Endocrinol Diabetes. 2001;109(1):47-51. Review. [citation only]
Absence of sodium/iodide symporter gene mutations in differentiated human thyroid carcinomas.Russo D, Manole D, Arturi F, Suarez HG, Schlumberger M, Filetti S, Derwahl M. Thyroid. 2001 Jan;11(1):37-9. [abstract only]
"Decrease or loss of the sodium iodide (Na+/I-) symporter (NIS) activity influences the suitability of using radioiodine to detect and treat metastatic thyroid tissues. In previous studies, the presence of the NIS transcript, albeit at lower expression levels, has been shown in most thyroid differentiated carcinomas. In this study we searched for point mutations or other genetic alterations that may be responsible for an altered function of the NIS protein in tumors that still express NIS transcripts. Tumoral cDNAs derived from seven differentiated thyroid carcinomas (DTC), five papillary and two follicular, were analyzed by direct sequencing after polymerase chain reaction (PCR) amplification of the structural gene of the Na+/I- symporter. Neither mutations nor other genetic abnormalities were detected in any tumor sample examined. The data indicate that mutations or other genetic alterations of the NIS structural gene are not a major cause of the reduced iodide uptake in DTC."
Na(+)/I(-) symporter and Pendred syndrome gene and protein expressions in human extra-thyroidal tissues.Lacroix L, Mian C, Caillou B, Talbot M, Filetti S, Schlumberger M, Bidart JM. Eur J Endocrinol. 2001 Mar;144(3):297-302.
"OBJECTIVE: The expression of two recently identified iodide transporters, namely the sodium/iodide symporter (NIS) and pendrin, the product of the gene responsible for the Pendred syndrome (PDS), was studied in a series of various extra-thyroidal human tissues, and especially in those known to concentrate iodide.
METHODS: To this end, we used real-time kinetic quantitative PCR to detect NIS and PDS transcripts and immunohistochemistry for the analysis of their protein products.
RESULTS: NIS gene and protein expression was detected in most tissues known to concentrate iodine, and particularly in salivary glands and stomach. In contrast, PDS gene expression was restricted to a few tissues, such as kidney and Sertoli cells. Interestingly, in kidney, pendrin immunostaining was detected at the apical pole of epithelial cells of the thick ascending limb of the Henle's loop and of the distal convoluted tubule.
CONCLUSION: This study provides new insights on
the localization and expression of two genes involved in iodide
transport and emphasizes the interest of combining real-time
quantitative PCR and immunohistochemistry for the comparison of gene
and protein expression in tissues."
Sodium-iodide symporter (NIS) gene expression in lymph-node metastases of papillary thyroid carcinomas.Arturi F, Russo D, Giuffrida D, Schlumberger M, Filetti S. Eur J Endocrinol. 2000 Nov;143(5):623-7.
"OBJECTIVE: To investigate the molecular mechanisms underlying the influence of alteration of iodine trapping on the prognosis of metastatic papillary thyroid carcinomas, focusing on the expression of the Na+/I(-) symporter (NIS).
DESIGN: We evaluated the expression of the NIS gene in a series of 11 enlarged neck lymph-node metastases of papillary thyroid carcinomas, including four patients in whom an enlarged lymph node represented the first sign of the tumoral disease. Nine lymph nodes, either reactive or metastatic for non-thyroid tumors, were also investigated.
METHODS: Expression of the NIS gene was evaluated by RT-PCR in material obtained by fine-needle aspiration biopsy.
RESULTS: The NIS gene was expressed in eight (73%) of 11 differentiated thyroid cancer metastatic lymph nodes examined. Five of these metastatic lymph nodes were positive at the post-treatment total-body iodine-131 scan; in the other three, the total-body scan showed no uptake in the metastatic tissues, indicating an alteration downstream to the NIS mRNA synthesis causing the loss of iodide uptake. As expected, when the NIS mRNA expression was absent, total-body (131)I scan showed no uptake in the metastatic lymph nodes.
CONCLUSIONS: Our study demonstrates that NIS gene expression may be absent in metastatic differentiated thyroid carcinomas and that different mechanisms, other than loss of NIS transcription, may also be involved in the loss of iodide uptake in metastatic thyroid cells. Study of NIS gene expression in the metastatic lymph nodes, therefore, may provide useful information in the management of patients with thyroid carcinoma."
Expression of Na+/I- symporter and Pendred syndrome genes in trophoblast cells.Bidart JM, Lacroix L, Evain-Brion D, Caillou B, Lazar V, Frydman R, Bellet D, Filetti S, Schlumberger M. J Clin Endocrinol Metab. 2000 Nov;85(11):4367-72.
"Placental iodide transport is critical for the fetal thyroid function, but the molecular mechanisms of this transport are not understood. The expression of two recently identified iodide transporters, namely the sodium/iodide symporter (NIS) and pendrin, the product of the gene responsible for the Pendred syndrome (PDS), was studied using real-time kinetic quantitative PCR and immunohistochemistry 1) in placental tissues collected at different gestational ages and 2) in primary cultures of villous cytotrophoblast cells (VCT) that differentiate and fuse over 2-3 days in vitro to form villous syncytiotrophoblast (VSCT) cells. Both NIS and PDS genes are expressed in placenta, albeit at low levels compared with those in thyroid tissue. NIS gene expression in placental samples from first trimester and term pregnancies was similar. In contrast, the expression of PDS gene was higher in term than in first trimester pregnancy samples. In vitro, NIS gene was expressed at a high level in VCT obtained from first trimester pregnancy, and its expression decreased by 3- to 4-fold during the differentiation of VCT in VSCT. Expression of NIS was lower (up to 30-fold) in VCT obtained in placental samples from third trimester than from first trimester pregnancy. In contrast, the expression of PDS gene was low in VCT and increased by 5- to 10-fold during VSCT formation; this was observed in cells isolated from placental samples of both first trimester and term pregnancies. Immunohistochemical analysis showed that NIS protein was present on the entire membrane of VCT, whereas pendrin was mainly located at the brush border membrane of VSCT, facing the mother. In conclusion, 1) NIS and PDS genes are differently expressed in the placenta during gestation; and 2) whereas pendrin is expressed at the brush border membrane of syncytiotrophoblast cells, NIS protein is mainly located in the cytotrophoblast layer."
Expression of pendrin and the Pendred syndrome (PDS) gene in human thyroid tissues.Bidart JM, Mian C, Lazar V, Russo D, Filetti S, Caillou B, Schlumberger M. J Clin Endocrinol Metab. 2000 May;85(5):2028-33.
"The gene recently cloned
that is responsible for the Pendred syndrome (PDS), an autosomal
recessive disease characterized by goiter and congenital sensorineural
deafness, is mainly expressed in the thyroid gland. Its product,
designated pendrin, was shown to transport chloride and iodide. To
investigate whether the PDS gene is altered during thyroid
tumorigenesis, PDS gene expression and pendrin expression were studied
using real-time kinetic quantitative PCR and antipeptide antibodies,
respectively, in normal, benign, and malignant human thyroid tissues.
The results were then compared to those observed for sodium/iodide
symporter (NIS) expression. In normal tissue, pendrin is localized at
the apical pole of thyrocytes, and this in contrast to the basolateral
location of NIS. Immunostaining for pendrin was heterogeneous both
inside and among follicles. In hyperfunctioning adenomas, the PDS
messenger ribonucleic acid level was in the normal range, although
immunohistochemical analysis showed strong staining in the majority of
follicular cells. In hypofunctioning adenomas, mean PDS gene
expression was similar to that detected in normal thyroid tissues, but
pendrin immunostaining was highly variable. In thyroid carcinomas, PDS
gene expression was dramatically decreased, and pendrin immunostaining
was low and was positive only in rare tumor cells. This expression
profile was similar to that observed for the NIS gene and its protein
product. In conclusion, our study demonstrates that pendrin is located
at the apical membrane of thyrocytes and that PDS gene expression is
decreased in thyroid carcinomas."
Adenovirus-mediated transfer of the thyroid sodium/iodide symporter gene into tumors for a targeted radiotherapy.Boland A, Ricard M, Opolon P, Bidart JM, Yeh P, Filetti S, Schlumberger M, Perricaudet M. Cancer Res. 2000 Jul 1;60(13):3484-92.
"The Na+/I- symporter (NIS) present in the membranes of thyroid cells is responsible for the capacity of the thyroid to concentrate iodide. This allows treatment of thyroid cancers with 131I. We propose to enlarge this therapeutic strategy to nonthyroid tumors by using an adenoviral vector to deliver the NIS gene into the tumor cells. We constructed a recombinant adenovirus encoding the rat NIS gene under the control of the cytomegalovirus promoter (AdNIS). Infection of SiHa cells (human cervix tumor cells) with AdNIS resulted in perchlorate-sensitive 125I uptake by these cells to a level 125-225 times higher than that in noninfected cells. Similar results were obtained for other human tumor cell lines, including MCF7 and T-47D (mammary gland), DU 145 and PC-3 (prostate), A549 (lung), and HT-29 (colon), demonstrating that the AdNIS vector can function in tumor cells of various origins. In addition, AdNIS-infected tumor cells were selectively killed by exposure to 131I, as revealed by clonogenic assays. To assess the efficiency of this cancer gene therapy strategy in vivo, we injected the AdNIS vector in human tumors (SiHa or MCF7 cells) established s.c. in nude mice. Immunohistological analysis confirmed the expression of the NIS protein in the tumor. Three days after intratumoral injection, AdNIS-treated tumors could specifically accumulate 125I or 123I, as revealed by kinetics and imaging experiments. A quantitative analysis demonstrated that the uptake in AdNIS-injected tumors was 4-25 times higher than that in nontreated tumors. On average, 11% of the total amount of injected 125I could be recovered per gram of AdNIS-treated tumor tissue. Altogether, these data indicate that AdNIS is very efficient in triggering significant iodide uptake by a tumor, outlining the potential of this novel cancer gene therapy approach for a targeted radiotherapy."
Sodium/iodide symporter: a key transport system in thyroid cancer cell metabolism.Filetti S, Bidart JM, Arturi F, Caillou B, Russo D, Schlumberger M. Eur J Endocrinol. 1999 Nov;141(5):443-57. Review.
"The recent cloning of the gene encoding the sodium/iodide symporter (NIS) has enabled better characterization of the molecular mechanisms underlying iodide transport, thus opening the way to clarifying its role in thyroid diseases. Several studies, at both the mRNA and the protein expression levels, have demonstrated that TSH, the primary regulator of iodide uptake, upregulates NIS gene expression and NIS protein abundance, both in vitro and in vivo. However, other factors, including iodide, retinoic acid, transforming growth factor-beta, interleukin-1alpha and tumour necrosis factor alpha, may participate in the regulation of NIS expression. Investigation of NIS mRNA expression in different thyroid tissues has revealed increased levels of expression in Graves' disease and toxic adenomas, whereas a reduction or loss of NIS transcript was detected in differentiated thyroid carcinomas, despite the expression of other specific thyroid markers. NIS mRNA was also detected in non-thyroid tissues able to concentrate radioiodine, including salivary glands, stomach, thymus and breast. The production of specific antibodies against the NIS has facilitated study of the expression of the symporter protein. Despite of the presence of high levels of human (h)NIS mRNA, normal thyroid glands exhibit a heterogeneous expression of NIS protein, limited to the basolateral membrane of the thyrocytes. By immunohistochemistry, staining of hNIS protein was stronger in Graves' and toxic adenomas and reduced in thyroid carcinomas. Measurement of iodide uptake by thyroid cancer cells is the cornerstone of the follow-up and treatment of patients with thyroid cancer. However, radioiodide uptake is found only in about 67% of patients with persistent or recurrent disease. Several studies have demonstrated a decrease in or a loss of NIS expression in primary human thyroid carcinomas, and immunohistochemical studies have confirmed this considerably decreased expression of the NIS protein in thyroid cancer tissues, suggesting that the low expression of NIS may represent an early abnormality in the pathway of thyroid cell transformation, rather than being a consequence of cancer progression. The relationship between radioiodine uptake and NIS expression by thyroid cancer cells require further study. New strategies, based on manipulation of NIS expression, to obtain NIS gene reactivation or for use as NIS gene therapy in the treatment of radiosensitive cancer, are also being investigated."
Expression of the Na+/I- symporter gene in human thyroid tumors: a comparison study with other thyroid-specific genes.Lazar V, Bidart JM, Caillou B, Mahe C, Lacroix L, Filetti S, Schlumberger M. J Clin Endocrinol Metab. 1999 Sep;84(9):3228-34.
"The expression of 4 thyroid tissue-specific genes [Na+/I- symporter (NIS), thyroid peroxidase (TPO), thyroglobulin (Tg), TSH receptor (TSH-R)] as well as of the glucose transporter type 1 (Glut1) gene was analyzed in 90 human thyroid tissues Messenger ribonucleic acids were extracted from 43 thyroid carcinomas (38 papillary and 5 follicular), 24 cold adenomas, 5 Graves' thyroid tissues, 8 toxic adenomas, and 5 hyperplastic thyroid tissues; 5 normal thyroid tissues were used as reference. A kinetic quantitative PCR method, based on the fluorescent TaqMan methodology and real-time measurement of fluorescence, was used. NIS expression was decreased in 40 of 43 thyroid carcinomas (10- to 1200-fold) and in 20 of 24 cold adenomas (2- to 700-fold); it was increased in toxic adenomas and Graves' thyroid tissues (up to 140-fold). TPO expression was decreased in thyroid carcinomas, but was normal in cold adenomas; it was increased in toxic adenomas and Graves' thyroid tissues Tg expression was decreased in thyroid carcinomas, but was normal in the other tissues. TSH-R expression was normal in most tissues studied and was decreased in only some thyroid carcinomas. In thyroid cancer tissues, a positive relationship was found between the individual levels of expression of NIS, TPO, Tg and TSH-R. No relationship was found with the age of the patient. Higher tumor stages (stages >I vs stage I) were associated with lower expression of NIS (P = 0.03) and TPO (P < 0.01). Expression of the Glut1 gene was increased in 1 of 24 adenomas and in 8 of 43 thyroid carcinomas. In 6 thyroid carcinoma patients, 131I uptake was studied in vivo; NIS expression was low in all samples; 3 patients with normal Glut-1 gene expression had 131I uptake in metastases, whereas the other 3 patients with increased Glut-1 gene expression had no detectable 131I uptake. In conclusion, this study shows 1) a reduced expression of NIS gene in most hypofunctioning benign and malignant thyroid tumors; 2) a differential regulation of the expression of thyroid-specific genes; 3) an increased expression of Glut-1 gene in some malignant tumors that may suggest a role for glucose derivative tracers to detect in vivo thyroid cancer metastases by positron emission tomography scanning."
Iodide symporter gene expression in normal and transformed rat thyroid cells.Trapasso F, Iuliano R, Chiefari E, Arturi F, Stella A, Filetti S, Fusco A, Russo D. Eur J Endocrinol. 1999 May;140(5):447-51.
"OBJECTIVE: Decrease or loss of the Na+/I- symporter (NIS) activity profoundly affects the suitability of the use of radioiodine to detect or treat metastatic thyroid tissues. The aim of our study was to verify whether specific oncogene abnormalities were responsible for the alteration in NIS activity in thyroid cells.
DESIGN AND METHODS: Expression of the NIS gene was investigated by Northern blot analysis in normal and in some oncogene-transformed cell lines with different degrees of malignancy which had lost the iodide uptake ability.
RESULTS: NIS gene expression was up-regulated by TSH in a dose-dependent and time-dependent way in normal PC Cl 3 cells. The same effect was observed by activating the cAMP-dependent pathway by forskolin. Conversely, insulin and 12-O-tetradecanoylphorbol-13-acetate (TPA) showed a partial inhibitory effect on NIS gene expression. The oncogene-transformed cell lines PC v-erbA, PC HaMSV, PC v-raf, and PC E1A cells showed reduced NIS mRNA levels compared with the normal PC Cl 3 cells. Conversely, an almost complete absence of NIS gene expression was found in PC RET/PTC, PC KiMSV, PC p53(143ala), and PC PyMLV cell lines.
CONCLUSIONS: Our data show that oncogene activation could play a role in affecting the iodide uptake ability in thyroid tumoral cells; different mechanisms are involved in the oncogene-dependent loss of NIS activity in transformed thyroid cells."
Na+/I- symporter distribution in human thyroid tissues: an immunohistochemical study.Caillou B, Troalen F, Baudin E, Talbot M, Filetti S, Schlumberger M, Bidart JM. J Clin Endocrinol Metab. 1998 Nov;83(11):4102-6.
"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."
Iodide symporter gene expression in human thyroid tumors.Arturi F, Russo D, Schlumberger M, du Villard JA, Caillou B, Vigneri P, Wicker R, Chiefari E, Suarez HG, Filetti S. J Clin Endocrinol Metab. 1998 Jul;83(7):2493-6.
"Expression of the Na+/I- symporter (NIS) gene
was investigated by RT-PCR in a selected series of 26 primary thyroid
carcinomas (19 papillary, 5 follicular, and 2 anaplastic). Fifteen
follicular adenomas (11 "cold" and 4 "hot" adenomas) were also
studied. Five of 19 papillary thyroid cancer did not express NIS
messenger ribonucleic acid (mRNA). In all but 1 follicular cancer, NIS
transcript was fully detected. In anaplastic tissue, NIS mRNA was only
barely detected in 1 case. All of the follicular thyroid adenomas
except 1 expressed the NIS gene. In contrast, all tumors studied
excluding the anaplastic histotype fully expressed thyroglobulin and
thyroid peroxidase mRNA transcripts. In 2 patients, a lower expression
(3- to 5-fold) of NIS mRNA was found in metastasis by dot blot
analysis compared with those in both normal and primary neoplastic
thyroid tissue. Four of 8 differentiated thyroid cancer patients
selected for the presence of metastases with negative posttherapy 131I
total body scan showed the lack of NIS gene expression in their
primary cancer. This defect, at least in these cases, is a somatic and
intrinsic lesion of the primary cancer cells and is not due to a
dedifferentiation process in the metastatic tissue. The early
detection of the loss of NIS gene expression in the primary cancer,
therefore, may provide useful information for the management of
differentiated thyroid cancer patients." |
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