Cloning of a functional promoter of the human sodium/iodide-symporter gene.
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ABSTRACT:
SUBMITTER: Behr M
PROVIDER: S-EPMC1219361 | biostudies-other | 1998 Apr
REPOSITORIES: biostudies-other
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Project description:Background: The ability of thyroid follicular epithelial cells to accumulate iodide via the sodium/iodide symporter (NIS) is exploited to successfully treat most thyroid cancers, although a subset of patients lose functional NIS activity and become unresponsive to radioiodide therapy, with poor clinical outcome. Our knowledge of NIS regulation remains limited, however. While numerous membrane proteins are functionally regulated via dimerization, there is little definitive evidence of NIS dimerization, and whether this might impact upon radioiodide uptake and treatment success is entirely unknown. We hypothesized that NIS dimerizes and that dimerization is a prerequisite for iodide uptake. Methods: Coimmunoprecipitation, proximity ligation, and Förster resonance energy transfer (FRET) assays were used to assess NIS:NIS interaction. To identify residues involved in dimerization, a homology model of NIS structure was built based on the crystal structure of the dimeric bacterial protein vSGLT. Results: Abundant cellular NIS dimerization was confirmed in vitro via three discrete methodologies. FRET and proximity ligation assays demonstrated that while NIS can exist as a dimer at the plasma membrane (PM), it is also apparent in other cellular compartments. Homology modeling revealed one key potential site of dimeric interaction, with six residues <3Å apart. In particular, NIS residues Y242, T243, and Q471 were identified as critical to dimerization. Individual mutation of residues Y242 and T243 rendered NIS nonfunctional, while abrogation of Q471 did not impact radioiodide uptake. FRET data show that the putative dimerization interface can tolerate the loss of one, but not two, of these three clustered residues. Conclusions: We show for the first time that NIS dimerizes in vitro, and we identify the key residues via which this happens. We hypothesize that dimerization of NIS is critical to its trafficking to the PM and may therefore represent a new mechanism that would need to be considered in overcoming therapeutic failure in patients with thyroid cancer.
| S-EPMC6797079 | biostudies-literature
Project description:Radioiodine is a routine therapy for differentiated thyroid cancers. Non-thyroid cancers may be treated with radio-iodine following transfection with the human sodium/iodide symporter (hNIS) gene. The glial fibrillary acidic protein (GFAP) promoter is an effective tumor-specific promoter for gene expression and thus may be useful in targeted gene therapy of malignant glioma. The present study used GFAP promoter-modulated expression of the hNIS gene in an experimental model of radioiodine-based treatment for malignant glioma. Cells were transfected using a recombination adeno-virus and evaluated in cells by studying the transfected transgene expression through western blot analysis, (125)I uptake and efflux, clonogenicity following (131)I treatment and radioiodine therapy using a U87 xenograft nude mouse model. Following transfection with the hNIS gene, the cells showed 95-70-fold higher (125)I uptake compared with the control cells transfected with Ad-cytomegalovirus (CMV)-enhanced green fluorescent protein (EGFP). The western blotting revealed bands of ∼70, 49 and 43 kDa, consistent with the hNIS, GFAP and β-actin proteins. The clonogenic assay indicated that, following exposure to 500 μCi of (131)I-iodide for 12 h, >90% of cells transfected with the hNIS gene were killed. Ad-GFAP-hNIS-transfected and 2 mCi (131)I-injected U87 xenograft nude mice survived the longest of the three groups. The hNIS-expressing tumor tissue accumulated (99m)TcO(4) rapidly within 30 min of it being intraperitoneally injected. The experiments demonstrated that effective (131)I therapy was achieved in the malignant glioma cell lines following the induction of tumor-specific iodide uptake activity by GFAP promoter-directed hNIS gene expression in vitro and in vivo. (131)I therapy retarded Ad-GFAP-hNIS transfected-tumor growth following injection with (131)I in U87 xenograft-bearing nude mice.
| S-EPMC3573145 | biostudies-literature
Project description:For decades, sodium/iodide symporter NIS-mediated iodide uptake has played a crucial role in the radioactive ablation of thyroid cancer cells. NIS-based gene therapy has also become a promising tool for the treatment of tumors of extrathyroidal origin. But its applicability has been hampered by reduced expression of NIS, resulting in a moderated capacity to accumulate 131I and in inefficient ablation. Despite numerous preclinical enhancement strategies, the understanding of NIS expression within tumors remains limited. This study aims at a better understanding of the functional behavior of exogenous NIS expression in the context of malignant solid tumors that are characterized by rapid growth with an insufficient vasculature, leading to hypoxia and quiescence. Using subcutaneous HT29NIS and K7M2NIS tumors, we show that NIS-mediated uptake and NIS expression at the plasma membrane of cancer cells are impaired in the intratumoral regions. For a better understanding of the underlying molecular mechanisms induced by hypoxia and quiescence (separately and in combination), we performed experiments on HT29NIS cancer cells. Hypoxia and quiescence were both found to impair NIS-mediated uptake through mechanisms including NIS mis-localization. Modifications in the expression of proteins and metabolites involved in plasma membrane localization and in energy metabolism were found using untargeted proteomics and metabolomics approaches. In conclusion, our results provide evidence that hypoxia and quiescence impair NIS expression at the plasma membrane, and iodide uptake. Our study also shows that the tumor microenvironment is an important parameter for successful NIS-based cancer treatment.
| S-EPMC7679261 | biostudies-literature
Project description:The aberrant expression of human sodium iodide symporter (NIS) in breast cancer (BC) has raised the possibility of using targeted radioiodide therapy. Here we investigate modulation of endogenous, functional NIS expression by histone deacetylase inhibitors (HDACi) in vitro and in vivo. Luciferase reporter based initial screening of six different HDACi shows 2-10 fold enhancement of NIS promoter activity in majority of the cell types tested. As a result of drug treatment, endogenous NIS transcript and protein shows profound induction in BC cells. To get an insight on the mechanism of such transcriptional activation, role of Stat4, CREB and other transcription factors are revealed by transcription factor profiling array. Further, NIS-mediated intracellular iodide uptake also enhances substantially (p < 0.05) signifying functional relevance of the transcriptional modulation strategy. Gamma camera imaging confirms 30% higher uptake in VPA or NaB treated BC tumor xenograft. Corroborating with such functional impact of NIS, significant reduction in cell survival (p < 0.005) is observed in VPA, NaB or CI994 drug and (131)I combination treatment in vivo indicating effective radioablation. Thus, for the first time this study reveals the mechanistic basis and demonstrates functional relevance of HDACi pre-treatment strategy in elevating NIS gene therapy approach for BC management in clinic.
| S-EPMC4726020 | biostudies-literature
Project description:BackgroundPropylthiouracil (PTU) and methimazole (MMI) are drugs that are widely used to treat Graves' disease. Although both exert an antithyroid effect primarily by blocking thyroid peroxidase activity, their molecular structure and other actions are different. We hypothesized that PTU and MMI may have differential effects on thyroid-specific gene expression and function.MethodsThe effects of PTU and MMI on thyroid-specific gene expression and function were examined in rat thyroid FRTL-5 cells using DNA microarray, reverse transcriptase (RT)-polymerase chain reaction (PCR), real-time PCR, Western blot, immunohistochemistry, and radioiodine uptake studies.ResultsDNA microarray analysis showed a marked increase in sodium/iodide symporter (NIS) gene expression after PTU treatment, whereas MMI had no effect. RT-PCR and real-time PCR analysis revealed that PTU-induced NIS mRNA levels were comparable to those elicited by thyroid-stimulating hormone (TSH). PTU increased 5'-1880-bp and 5'-1052-bp activity of the rat NIS promoter. While PTU treatment also increased NIS protein levels, the size of the induced protein was smaller than that induced by TSH, and the protein localized predominantly in the cytoplasm rather than the plasma membrane. Accumulation of (125)I in FRTL-5 cells was increased by PTU stimulation, but this effect was weaker than that produced by TSH.ConclusionsWe found that PTU induces NIS expression and iodide uptake in rat thyroid FRTL-5 cells in the absence of TSH. Although PTU and MMI share similar antithyroid activity, their effects on other thyroid functions appear to be quite different, which could affect their therapeutic effectiveness.
| S-EPMC3407387 | biostudies-literature
Project description:Iodine has shown promise in enhancing radiotherapy. However, conventional iodine compounds show fast clearance and low retention inside cancer cells, limiting their application as a radiosensitizer. Herein, we synthesize poly(maleic anhydride-alt-1-octadecene) coated KI nanoparticles (PMAO-KI NPs) and evaluate their potential for enhancing radiotherapy. Owing to the polymer coating, the KI core of PMAO-KI NPs is not instantly dissolved in aqueous solutions but slowly degraded, allowing for controlled release of iodide (I-). I- is transported into cells via the sodium iodide symporter (NIS), which is upregulated in breast cancer cells. Our results show that PMAO-KI NPs can enhance radiation-induced production of reactive oxygen species such as hydroxyl radicals. When tested in vitro with MCF-7 cells, PMAO-KI NPs promote radiation-induced DNA double-strand breaks and lipid peroxidation, causing a drop in cancer cell viability and reproductivity. When tested in MCF-7 bearing mice, PMAO-KI NPs show significant radiosensitizing effects, leading to complete tumor eradication in 80% of the treated animals without inducing additional toxicity. Overall, our strategy exploits electrolyte nanoparticles to deliver iodide into cancer cells through NIS, thus promoting radiotherapy against breast cancer.
| S-EPMC9035482 | biostudies-literature
Project description:The sodium/iodide symporter (NIS) is the essential plasma membrane protein that mediates active iodide (I-) transport into the thyroid gland, the first step in the biosynthesis of the thyroid hormones-the master regulators of intermediary metabolism. NIS couples the inward translocation of I- against its electrochemical gradient to the inward transport of Na+ down its electrochemical gradient1,2. For nearly 50 years before its molecular identification3, NIS was the molecule at the centre of the single most effective internal radiation cancer therapy: radioiodide (131I-) treatment for thyroid cancer2. Mutations in NIS cause congenital hypothyroidism, which must be treated immediately after birth to prevent stunted growth and cognitive deficiency2. Here we report three structures of rat NIS, determined by single-particle cryo-electron microscopy: one with no substrates bound; one with two Na+ and one I- bound; and one with one Na+ and the oxyanion perrhenate bound. Structural analyses, functional characterization and computational studies show the substrate-binding sites and key residues for transport activity. Our results yield insights into how NIS selects, couples and translocates anions-thereby establishing a framework for understanding NIS function-and how it transports different substrates with different stoichiometries and releases substrates from its substrate-binding cavity into the cytosol.
| S-EPMC10501339 | biostudies-literature
Project description:To test the feasibility of using the survivin promoter to induce specific expression of sodium/iodide symporter (NIS) in cancer cell lines and tumors for targeted use of radionuclide therapy, a recombinant adenovirus, Ad-SUR-NIS, that expressed the NIS gene under control of the survivin promoter was constructed. Ad-SUR-NIS mediating iodide uptake and cytotoxicity was performed in vitro. Scintigraphic, biodistribution and radioiodine therapy studies were performed in vivo. PC-3 (prostate); HepG2 (hepatoma) and A375 (melanoma) cancer cells all exhibited perchlorate-sensitive iodide uptake after infection with Ad-SUR-NIS, approximately 50 times higher than that of negative control Ad-CMV-GFP-infected cells. No significant iodide uptake was observed in normal human dental pulp fibroblast (DPF) cells after infection with Ad-SUR-NIS. Clonogenic assays demonstrated that Ad-SUR-NIS-infected cancer cells were selectively killed by exposure to (131)I. Ad-SUR-NIS-infected tumors show significant radioiodine accumulation (13.3 ± 2.85% ID per g at 2 h post-injection), and the effective half-life was 3.1 h. Moreover, infection with Ad-SUR-NIS in combination with (131)I suppressed tumor growth. These results indicate that expression of NIS under control of the survivin promoter can likely be used to achieve cancer-specific expression of NIS in many types of cancers. In combination with radioiodine therapy, this strategy is a possible method of cancer gene therapy.
| S-EPMC3025317 | biostudies-literature
Project description:Radioactive iodine (RAI) is a key therapeutic modality for thyroid cancer. Loss of RAI uptake in thyroid cancer inversely correlates with patient's survival. In this review, we focus on the challenges encountered in delivering sufficient doses of I-131 to eradicate metastatic lesions without increasing the risk of unwanted side effects. Sodium iodide symporter (NIS) mediates iodide influx, and NIS expression and function can be selectively enhanced in thyroid cells by thyroid-stimulating hormone. We summarize our current knowledge of NIS modulation in normal and cancer thyroid cells, and we propose that several reagents evaluated in clinical trials for other diseases can be used to restore or further increase RAI accumulation in thyroid cancer. Once validated in preclinical mouse models and clinical trials, these reagents, mostly small-molecule inhibitors, can be readily translated into clinical practice. We review available genetically engineered mouse models of thyroid cancer in terms of their tumor development and progression as well as their thyroid function. These mice will not only provide important insights into the mechanisms underlying the loss of RAI uptake in thyroid tumors but will also serve as preclinical animal models to evaluate the efficacy of candidate reagents to selectively increase RAI uptake in thyroid cancers. Taken together, we anticipate that the optimal use of RAI in the clinical management of thyroid cancer is yet to come in the near future.
| S-EPMC4458071 | biostudies-other
Project description:Stem cell-based therapies are a promising approach for the treatment of degenerative muscular diseases; however, clinical trials have shown inconclusive and even disappointing results so far. Noninvasive cell monitoring by medicine imaging could improve the understanding of the survival and biodistribution of cells following injection. In this study, we assessed the canine sodium iodide symporter (cNIS) reporter gene as an imaging tool to track by single-photon emission computed tomography (SPECT/CT) transduced canine myoblasts after intramuscular (IM) administrations in dogs. cNIS-expressing cells kept their myogenic capacities and showed strong 99 mTc-pertechnetate (99 mTcO4 -) uptake efficiency both in vitro and in vivo. cNIS expression allowed visualization of cells by SPECT/CT along time: 4 h, 48 h, 7 days, and 30 days after IM injection; biopsies collected 30 days post administration showed myofiber's membranes expressing cNIS. This study demonstrates that NIS can be used as a reporter to track cells in vivo in the skeletal muscle of large animals. Our results set a proof of concept of the benefits NIS-tracking tool may bring to the already challenging cell-based therapies arena in myopathies and pave the way to a more efficient translation to the clinical setting from more accurate pre-clinical results.
| S-EPMC7293195 | biostudies-literature