Rat sodium iodide symporter for radioiodide therapy of cancer.

Design and development of new approaches for targeted radiotherapy of cancer and improvement of therapeutic index by more local radiation therapy are very important issues. Adenovirus-mediated delivery of the sodium iodide symporter (NIS) gene to cancer cells is a powerful technique to concentrate lethal radiation in tumor cells and eradicate tumors with increased therapeutic index. A replication-defective adenoviral vector expressing the rat NIS gene (Ad-rNIS) was used for in vitro gene delivery and into human prostate cancer xenografts to study antitumor effect. Robust function of the rat symporter was detected in DU145, T47D, and HCT-15 human cancer cell lines transduced with Ad-rNIS. All three cancer cell lines successfully transferred functionally active rat symporter to the plasma membrane, resulting in very high levels of iodine-125 accumulation. Three-dimensional multicellular tumor spheroids derived from DU145 human prostate cancer cells were transduced with Ad-rNIS and incubated with (131)I for 24 hours. After treatment, spheroids rapidly decreased in size and disappeared within 10 days. In vivo data revealed an inhibition of tumor growth in athymic nude mice after intratumoral Ad-rNIS injection followed by (131)I administration. Eighty-eight percent of experimental mice survived >30 days, whereas control groups had only 18% survival >30 days. This is the first report that demonstrates the rat NIS gene can effectively induce growth arrest of human tumor xenografts after in vivo adenoviral gene delivery and (131)I administration. The data confirm our hypothesis that the rat NIS gene is an attractive suicide gene candidate for cancer treatment.     

Systemic retinoic acid treatment induces sodium/iodide symporter expression and radioiodide uptake in mouse breast cancer models

Lactating breast tissue and some breast cancers express the sodium/iodide symporter (NIS) and concentrate iodide. We recently demonstrated that all-trans retinoic acid (tRA) induces both NIS gene expression and iodide accumulation in vitro in well-differentiated human breast cancer cells (MCF-7). In the present study, we investigated the in vivo efficacy and specificity of tRA-stimulated iodide accumulation in mouse breast cancer models. Immunodeficient mice with MCF-7 xenograft tumors were treated with systemic tRA for 5 days. Iodide accumulation in the xenograft tumors was markedly increased, approximately 15-fold greater than levels without treatment, and the effects were tRA dose dependent. Iodide accumulation in other organs was not significantly influenced by tRA treatment. Significant induction of NIS mRNA and protein in the xenograft tumors was observed after tRA treatment. Iodide accumulation and NIS mRNA expression were also selectively induced in breast cancer tissues in transgenic mice expressing the oncogene, polyoma virus middle T antigen. These data demonstrate selective induction of functional NIS in breast cancer by tRA. Treatment with short-term systemic retinoic acid, followed by radioiodide administration, is a potential tool in the diagnosis and treatment of some differentiated breast cancer.     

Targeting sodium/iodide symporter gene expression for estrogen-regulated imaging and therapy in breast cancer

Expression of the sodium iodide symporter (hNIS) has been detected in breast cancer tissue, but frequently, not at the levels necessary to mediate (131)I accumulation. Transducing the hNIS gene into breast cancer cells with adenovirus could be a tractable strategy to render breast cancer susceptible to radioiodide therapy. We constructed the replication-incompetent virus, AdSERE, in which an estrogen-responsive promoter directs the expression of hNIS. In vitro, we demonstrate that AdSERE mediates hNIS expression and iodide uptake in ER+ breast cancer cells. In vivo, we show that AdSERE-infected ER+ tumors can be imaged due to tracer accumulation; in addition, AdSERE in combination with therapeutic doses of (131)I suppresses tumor growth.     

全反式维甲酸对甲状腺癌细胞NIS基因表达及吸碘能力影响的实验研究

目的：探讨全反式维甲酸（ATRA）对甲状腺癌细胞株钠/碘同向转运体（NIS）基因表达、吸碘能力的影响,为ATRA用于放射性碘治疗甲状腺癌提供理论依据。方法：分别以不同浓度（10^-7mol/L、10^-6mol/L、10^-5mol/L、10^-4mol/L）的ATRA处理体外培养的甲状腺癌细胞株（FTC-133）,48h后利用半定量RT-PCR检测细胞NISmRNA表达,γ-计数仪检测细胞吸碘能力。结果：ARTA浓度在（0～10%-5）mol/L范围内,细胞NIS基因表达及吸碘能力随ARTA剂量的增加而增加（P〈0.05）。当ARTA浓度达10%-4mol/L时,增加与前一浓度相比无统计学意义（P〉0.05）。结论：ATRA可上调甲状腺癌FTC-133细胞NIS基因表达,增强其吸碘能力,而且这种作用在一定浓度范围内具有剂量依赖性。     

细胞因子对乳腺癌细胞钠碘转运体基因表达的调控

目的本实验通过三种细胞因子(肿瘤坏死因子-α,干扰素-γ和白细胞介素-6)对乳腺细胞钠碘转运体(NIS)基因表达的影响,探讨乳腺肿瘤组织NIS的表达特点和调控因素.方法采用乳腺癌细胞MCF-7和MB453进行培养,分别给予不同浓度的肿瘤坏死因子-α,干扰素-γ或白细胞介素-6刺激72 h.采用RT-PCR方法检测细胞中NIS mRNA表达情况.结果乳腺癌细胞在经过肿瘤坏死因子-α,干扰素-γ或白细胞介素-6刺激后,细胞中NIS的mRNA表达比对照组明显降低,并且与细胞因子浓度呈负相关.结论肿瘤坏死因子-α,干扰素-γ和白细胞介素-6对乳腺癌细胞MCF-7和MB453的NIS基因mRNA表达有抑制作用,这提示细胞因子可能通过调节乳腺癌NIS基因mRNA的表达,从而影响乳腺癌细胞对放射性碘治疗的敏感性.     

Ectopic expression of the thyroperoxidase gene augments radioiodide uptake and retention mediated by the sodium iodide symporter in non-small cell lung cancer

Radioiodide is an effective therapy for thyroid cancer. This treatment modality exploits the thyroid-specific expression of the sodium iodide symporter (NIS) gene, which allows rapid internalization of iodide into thyroid cells. To test whether a similar treatment strategy could be exploited in nonthyroid malignancies, we transfected non-small cell lung cancer (NSCLC) cell lines with the NIS gene. Although the expression of NIS allowed significant radioiodide uptake in the transfected NSCLC cell lines, rapid radioiodide efflux limited tumor cell killing. Because thyroperoxidase (TPO) catalyzes iodination of proteins and subsequently causes iodide retention within thyroid cells, we hypothesized that coexpression of both NIS and TPO genes would overcome this deficiency. Our results show that transfection of NSCLC cells with both human NIS and TPO genes resulted in an increase in radioiodide uptake and retention and enhanced tumor cell apoptosis. These findings suggest that single gene therapy with only the NIS gene may have limited efficacy because of rapid efflux of radioiodide. In contrast, the combination of NIS and TPO gene transfer, with resulting TPO-mediated organification and intracellular retention of radioiodide, may lead to more effective tumor cell death. Thus, TPO could be used as a therapeutic strategy to enhance the NIS-based radioiodide concentrator gene therapy for locally advanced lung cancer.     

Treatment of prostate cancer by radioiodine therapy after tissue-specific expression of the sodium iodide symporter

Causing prostate cancer cells to express functionally active sodium iodide symporter (NIS) by targeted NIS gene transfer might offer the possibility of radioiodine therapy of prostate cancer. Therefore, we investigated radioiodine accumulation and therapeutic effectiveness of 131I in NIS-transfected prostate cancer cells in vitro and in vivo. The human prostatic adenocarcinoma cell line LNCaP was stably transfected with NIS cDNA under the control of the prostate-specific antigen promoter. The stably transfected LNCaP cell line NP-1 showed perchlorate-sensitive, androgen-dependent iodide uptake in vitro that resulted in selective killing of these cells by 131I in an in vitro clonogenic assay. Xenografts were established in athymic nude mice and imaged using a gamma camera after i.p. injection of 500 microCi of 123I. In contrast to the NIS-negative control tumors (P-1) which showed no in vivo uptake of 123I, NP-1 tumors accumulated 25-30% of the total 123I administered with a biological half-life of 45 h. In addition, NIS protein expression in LNCaP cell xenografts was confirmed by Western blot analysis and immunohistochemistry. After a single i.p. application of a therapeutic 131I dose (3 mCi), significant tumor reduction was achieved in NP-1 tumors in the therapy group compared with P-1 tumors and tumors in the control group. In conclusion, a therapeutic effect of 131I has been demonstrated in prostate cancer cells after induction of tissue-specific iodide uptake activity by prostate-specific antigen promoter-directed NIS expression in vitro and in vivo. This study demonstrates the potential of NIS as a novel therapeutic gene for nonthyroidal cancers, in particular prostate cancer.     

甲状腺乳头状癌BRAFV600E基因突变与钠碘同向转运体表达的研究

目的:探讨甲状腺乳头状癌(PTC)患者中BRAFV600E基因突变及钠碘同向转运体(NIS)蛋白的表达及两者间的相关性.方法:收集2008-01-01—2011-01-01青岛大学医学院附属医院病理科PTC石蜡包埋组织30例,其中癌旁组织为正常组织(G正常组)15例,癌旁组织为结节性甲状腺肿组织(G结甲组)15例.对PTC组织行DNA提取、PCR扩增、基因测序检测BRAFV600E基因突变,同时采用免疫组化的方法分析NIS蛋白表达,结果以免疫组化评分(IHS)表示.结果:30例PTC均无BRAFV600E基因突变;30例PTC组织中NIS蛋白表达,从0～12分,G正常组IHS=(7.92±3.01)分,G结甲组IHS=(6.58±2.71)分,两组NIS差异无统计学1意义,t=1.11,P=0.95;BRAFV600E突变与NIS蛋白表达无相关性.结论:尚未发现癌旁不同的PTCBRAFV600E基因有突变及NIS蛋白表达的差异.BRAFV600E基因突变与NIS表达在PTC中的关系有待进一步研究.     

Radiofrequency induction on sodium/iodide symporter expression of thyroid cancer

Objective:The aim of this study was to investigate the ef ects of radiofrequency treatment on sodium/iodide symporter expression of thyroid cancer cells. Methods:In 29 thyroid cancer patients with low or no expression of soda\iodide symporter, the radio frequency combined 131I therapy was used, the whole-body scintigraphy and serum Ig were detected before and after the radiofrequency treatment. Results:The whole-body scintigraphy showed that 4 cases (4/29) before radiofrequency treatment had positive iodine uptake, 19 cases (19/29) two weeks after radiofrequency treatment had the positive iodine uptake, 12 cases (12/29) four weeks after radiofrequency treatment had the positive iodine uptake. Four weeks after radiofrequency treatment, 5 cases had increased serum Ig levels, 17 cases had decreased serum Ig levels, 7 cases showed no change. 25 cases (25/29) were ef ective, 15 cases (15/29) were cured. Conclusion:The radiofrequency induced the non-expressed the sodium/iodide symporter of thyroid cancer cells regain the iodine intake ability, it improved the clinical ef icacy of 131I therapy in dedif erentiated thyroid cancer.     

钠碘转运体转基因介导放射性碘治疗非甲状腺恶性肿瘤的研究进展

钠碘转运体(NIS)是一种能介导碘向细胞内转运的膜蛋白,可以配合放射性碘来治疗肿瘤.目前已经利用转基因技术使不表达或低表达NIS的非甲状腺恶性肿瘤细胞表达NIS蛋白.同时发现肿瘤细胞的低摄碘能力与NIS合成的量及NIS是否能正确锚着密切相关.当前努力的方向除促进NIS的表达和锚着,还要研究如何使肿瘤细胞摄入的碘能够在细胞内滞留足够长的时间以达到杀伤肿瘤的目的.目前已经在乳腺、前列腺、绒毛膜癌、非小细胞肺癌等肿瘤进行了细胞水平的转基因治疗研究.     

PI3K activation is associated with intracellular sodium/iodide symporter protein expression in breast cancer

Background  

The sodium/iodide symporter (NIS) is a membrane glycoprotein mediating active iodide uptake in the thyroid gland and is the molecular basis for radioiodide imaging and therapeutic ablation of thyroid carcinomas. NIS is expressed in the lactating mammary gland and in many human breast tumors, raising interest in similar use for diagnosis and treatment. However, few human breast tumors have clinically evident iodide uptake ability. We previously identified PI3K signaling as important in NIS upregulation in transgenic mouse models of breast cancer, and the PI3K pathway is commonly activated in human breast cancer.     

Effect of ligands of nuclear hormone receptors on sodium/iodide symporter expression and activity in breast cancer cells

Iodide uptake by normal and cancerous thyroid cells is an active process mediated by the sodium/iodide symporter (NIS). Using quantitative real-time RT-PCR, we found that all 22 fresh human breast cancer samples had very low NIS expression similar to levels in untreated MCF-7 breast cancer cells. 9-cis retinoic acid (9-cis RA), a ligand for both retinoic acid receptor (RAR)/retinoic X receptor (RXR) heterodimers as well as RXR/RXR homodimers, markedly induced NIS mRNA expression in MCF-7 breast cancer cells in a dose- and time-dependent fashion, with maximal levels occurring at 12 h. All-trans retinoic acid, ATRA, a RAR specific ligand had a similar potency. Among eight breast cancer cell lines, three out of four estrogen receptor (ER)-positive and zero of four ER-negative cell lines responded to 9-cis RA by increasing their expression of NIS. Combining a RAR with a RXR selective ligand enhanced both NIS mRNA expression and iodide uptake in MCF-7 cells. Similarly, a ligand for proliferator-activated receptor (PPAR) when combined with 9-cis RA synergistically increased both NIS mRNA levels and iodide uptake in these MCF-7 cells. The iodide uptake was blocked by KClO₄. In conclusions, these findings suggest that selected combinations of NHR ligands should be examined in a limited trial to determine if their administration to patients allows the use of radioactive iodine for diagnosis and possibly treatment of metastatic breast cancer.     

Visualization of endogenous p53-mediated transcription in vivo using sodium iodide symporter.

PURPOSE: To develop a gamma camera imaging method for the determination of endogenous gene expression, we evaluated the expression of endogenous p53 gene using human sodium iodide symporter (hNIS) gene as reporter. EXPERIMENTAL DESIGN: We constructed cis-p53RE-hNIS reporter vector placed under control of an artificial enhancer (p53RE). Moreover, we transfected it into human hepatoma cell line SK-Hep1 by liposome. Geneticin was used for the selection of stable transfectant (SK-Hep1p53NIS). To evaluate the function of hNIS, the inhibition study was examined with 1 mmol/L potassium perchlorate. After treatment of Adriamycin with serial dose for 24 hours, we measured the uptake of 125I and did Western blot analysis to evaluate expression of p53 protein. Tumor xenografts were produced in nude mice by s.c. injection of SK-Hep1p53NIS cells. After 7 days, scintigraphic images of nude mice before and after Adriamycin treatment were obtained using [99mTc]-pertechnetate. RESULTS: In the SK-Hep1p53NIS cells, Adriamycin-treated cells accumulated up to three times higher than did nontreated cells. Potassium perchlorate inhibited completely the uptake of 125I. As Adriamycin dose increased, radioiodide uptake was significantly correlated with activated p53 as well as total p53 protein level. When Adriamycin (2 mg/kg) was treated in the same mice, a significantly higher uptake of [99mTc]-pertechnetate was observed in SK-Hep1p53NIS xenografts compared with nontreated xenografts (P < 0.05, unpaired t test). CONCLUSIONS: These results suggest that p53 expression level can be monitored by NIS gene expression using cis-p53RE-hNIS system in vitro and in vivo.     

The rat sodium iodide symporter gene permits more effective radioisotope concentration than the human sodium iodide symporter gene in human and rodent cancer cells

Expression of the sodium iodide symporter (NIS) gene in tumor cells may provide a novel mechanism for treating cancer. The NIS mediates the normal physiological transport of iodide across the thyroid cell membrane. This mechanism of iodide uptake has been used to both diagnose and treat thyroid cancer. Tissue expression of the NIS is largely limited to the thyroid; therefore, expression of the NIS gene in cancer cells would allow for specific iodine uptake, radioisotope accumulation, and treatment. In this study, we directly compared the human and rat NIS (rNIS) for their ability to concentrate radioisotope into human and rodent cancer cells. Perchlorate-sensitive (125)I uptake in multiple cell lines was demonstrated following transduction with retroviral vectors expressing either the human or rNIS gene. Surprisingly, iodine uptake was consistently higher with the rNIS gene, up to 5-fold greater, when compared to the human gene, even within a variety of human tumor cell lines. This iodine uptake allowed for cell killing following (131)I treatment in NIS-transduced cells when assayed by in vitro clonogenic assays. These results demonstrate that the rNIS gene provides superior iodine uptake ability, and may be preferable for use in designing anticancer gene therapy approaches.     

MUC1 expression in primary breast cancer: the effect of tamoxifen treatment

This was a non-randomised single institution retrospective study. Forty-six banked frozen tumour specimens were obtained from a group of patients who had undergone 3 weeks of neoadjuvant treatment with tamoxifen between biopsy and surgery. Fifty-one comparison specimens were randomly selected from a group of concomitantly treated primary breast cancer patients who did not receive neoadjuvant tamoxifen. Specimen selection was not based on prognostic factors: hormone receptor status, patient age, or menopausal status. MUC1 expression and cell cycle distribution were assessed by flow cytometry. S-phase fraction of MUC1 positive and MUC1 negative cells were compared. A lower percentage of cells expressed MUC1 following 3-week tamoxifen treatment 18.2% versus 28.5% (p=0.03, Mann-Whitney) and lower levels of MUC1 expression were seen following tamoxifen treatment 31,519 molecules/cell versus 39,387 (p=0.04, Mann-Whitney). MUC1 positive cells, irrespective of treatment group, had a greater proportion of cells in S-phase of the cell cycle 27.9% versus 16.8% (p=0.0004, Mann-Whitney) and demonstrated more cases of aneuploidy 80.65% versus 42.6% (p<0.0001). MUC1 levels in primary tumours treated neoadjunctively with 3 weeks of tamoxifen were lower than a comparison group which did not receive tamoxifen. MUC1 should be explored further as an intermediate biomarker for assessment of treatment and prognosis.     

Endogenous expression of the sodium iodide symporter mediates uptake of iodide in murine models of colorectal carcinoma

The sodium iodide symporter (NIS) mediates iodide uptake into the thyroid. Because of this mechanism, differentiated thyroid cancer is susceptible for radioiodine therapy. Functional NIS expression in extrathyroidal tumors has been reported mainly in breast cancer. We screened colorectal tumors for NIS expression and investigated the mechanisms regulating NIS activity. Cell lines were screened for iodide uptake in vitro and NIS expression was evaluated by real‐time RT‐PCR, immunocytochemistry and immunoblotting. Iodide and pertechnetate uptake were evaluated in allograft tumors by biodistribution studies and scintigraphy. Tumors of transgenic mouse models for colorectal cancer harboring mutations in the oncogenes KRAS, β‐catenin or the tumor‐suppressor gene adenomatous‐polyposis coli (APC) were screened for NIS expression by RT‐PCR. In vitro, functional NIS activity was detected in murine CMT93 rectal carcinoma cells and NIS expression was verified on mRNA and protein level. Inhibition of tyrosine kinases increased iodide uptake. Inhibition of tyrosine phosphatases decreased iodide uptake. In vivo, functional NIS expression was preserved in CMT93 tumors and tumor uptake could be enhanced by treatment of mice with tyrosine kinase inhibitors. In transgenic murine models of colorectal cancer, 14% of endogenous tumors expressed elevated levels of NIS mRNA. We conclude that NIS is functionally expressed in a subset of murine colorectal tumors and its activity is regulated by tyrosine phosphorylation. Therefore, with specific tyrosine kinase inhibition, these tumors might be susceptible for radioiodine treatment. Further studies are justified to identify the specific pathways regulating NIS activity and to transfer these findings to human cell lines and tissues. © 2009 UICC     

Experimental targeted radioiodide therapy following transfection of the sodium iodide symporter gene: effect on clonogenicity in both two-and three-dimensional models

To evaluate the potential of the expression of the sodium/iodide symporter (NIS) as a means of targeting radioiodine to tumor cells, we have employed plasmid-mediated transfection of the NIS gene into a range of mammalian cell hosts. We observed perchlorate-inhibitable iodide uptake up to 41-fold over control in all NIS-transfected cells. We assessed the effect of NIS expression followed by exposure to 131I- on the clonogenic survival of UVW glioma cells. After exposure of two-dimensional monolayer cultures of UVW-NIS cells to 131I- at a radioactive concentration of 4 MBq/mL, clonogenic survival was reduced to 21%. Similar treatment of UVW-NIS cells in three-dimensional spheroid cultures resulted in a reduction of clonogenic survival to 2.5%. This increase in sensitivity to 131I- exposure is likely to be due to a radiological bystander effect. These results are very encouraging for the development of a novel cytotoxic gene-therapy strategy in which a radiological bystander effect plays a significant role in tumor cell sterilization.     

ER阳性乳腺癌中MUC1的强阳性表达及其与预后的关系

背景与目的:黏蛋白1(mucin 1,MUC1)主要作为血清学分子标记应用于乳腺癌患者术后肿瘤复发转移的监测,但其在乳腺癌患者术后早期检测对预后的价值尚不明确.本研究旨在通过检测乳腺癌组织中MUC1的强阳性表达,分析其与ER表达以及预后的关系,以探讨MUC1强阳性表达在乳腺癌术后早期检测对预后的作用.方法:采用免疫组织化学法检测134例乳腺癌组织中MUC1的强阳性表达情况,并分析其与ER表达以及预后的关系.结果:本组乳腺癌组织中MUC1强阳性表达率为47.0%,乳腺癌组织中MUC1强阳性表达与ER阳性表达存在着显著的正相关关系(x2=10.09,P＜0.01,r=0.27).在ER阴性乳腺癌患者中尚不能认为MUC1强阳性表达与预后相关(P=0.26);经单因素和多因素分析,在ER阳性并接受他莫昔芬治疗的乳腺癌患者中,MUC1强阳性表达、Her-2强阳性表达和淋巴结转移状态均是独立的预后因子(P＜0.05).同时,多因素分析表明Her-2强阳性表达的优势比最大(OR=12.41),淋巴结转移状态次之,MUC1强阳性表达最小.结论:在乳腺癌组织中MUC1强阳性表达与ER表达正相关,在ER阳性并接受他莫昔芬治疗的乳腺癌患者中MUC1强阳性表达具有独立的预后价值.