Radioiodine therapy, the most effective form of systemic radiotherapy available, is currently useful only for thyroid cancer because of the thyroid-specific expression of the human sodium iodide symporter （hNIS）. He...Radioiodine therapy, the most effective form of systemic radiotherapy available, is currently useful only for thyroid cancer because of the thyroid-specific expression of the human sodium iodide symporter （hNIS）. Here, we explore the efficacy of a novel form of gene therapy using prostate-specific membrane antigen （PSMA） promoter-mediated hNIS gene transfer followed by radioiodine administration for the treatment of castration-resistant prostate cancer （CRPC）. The androgen-dependent C33 LNCaP cell line and the androgen-independent C81 LNCaP cell line were transfected by adenovirus. PSMA promoter-hNIS （Ad.PSMApro-hNIS） or adenovirus.cytomegalovirus-hNIS containing the cytomegalovirus promoter （Ad.CMM-hNIS） or a control virus. The iodide uptake was measured in vitro. The in vivo iodide uptake by C81 cell xenografts in nude mice injected with an adenovirus carrying the hNIS gene linked to PSMA and the corresponding tumor volume fluctuation were assessed. Iodide accumulation was shown in different LNCaP cell lines after Ad.PSMApro-hNIS and Ad.CMV-hNIS infection, but not in different LNCaP cell lines after adenovirus.cytomegalovirus （Ad.CMV） infection. At each time point, higher iodide uptake was shown in the C81 cells infected with Ad.PSMApro-hNIS than in the C33 cells （P 〈 0.05）. An in vivo animal model showed a significant difference in 1311 radioiodine uptake in the tumors infected with Ad.PSMApro-hNIS, Ad.CMV-hNIS and control virus （P 〈 0.05） and a maximum reduction of tumor volume in mice infected with Ad.PSMApro-hNIS. These results show prostate-specific expression of the hNIS gene delivered by the PSMA promoter and effective radioiodine therapy of CRPC by the PSMA promoter-driven hNIS transfection.展开更多
To investigate human sodium/iodide symporter (hNIS) induced iodine uptake in human lung adenocarcinoma via baculovirus, a recombinant baculovirus encoding hNIS gene was constructed under the control of CMV promoter (B...To investigate human sodium/iodide symporter (hNIS) induced iodine uptake in human lung adenocarcinoma via baculovirus, a recombinant baculovirus encoding hNIS gene was constructed under the control of CMV promoter (Bac-CMV-hNIS). In vitro, baculovirus infected A549 cells accumulated about 27 times more 125I than that of noninfected cells. The 125I uptake was maximal after 30-min incubation of the cells, and efflux of the radioactivity was rapid, with 50% lost during the first 2 min after 125I-containing medium had been replaced by nonradioactive medium. Competition experiments in the presence of sodium perchlorate revealed a dose-dependent decrease of 125I uptake. Bac-CMV-hNIS infected tumor cells were selectively killed by exposure to 131I, as revealed by clonogenic assays. In nude mice, Bac-CMV-hNIS infected A549 cells accumulated more 131I than that of the control monitored by 1-h scintigraphy after 131I administration. The transduction of hNIS gene through baculovirus is sufficient to induce iodine transporting in A549 cells in vitro and in vivo, outlining the potential of this novel tumor gene imaging approach. But a rapid efflux of radioactivity from the tumor was shown in vivo and the in vivo therapy test showed no sign of effect.展开更多
Objective We investigated the correlation between the expression of the sodium-iodide symporter(NIS) and the detection of circulating tumor cells(CTCs) in differentiated thyroid carcinoma(DTC).Methods NIS expression i...Objective We investigated the correlation between the expression of the sodium-iodide symporter(NIS) and the detection of circulating tumor cells(CTCs) in differentiated thyroid carcinoma(DTC).Methods NIS expression in differentiated thyroid and the positive rate of CTCs in the peripheral blood were determined by immunohistochemistry S-P and flow cytometry from the records of 172 cases of differentiated thyroid carcinoma.Results Seventy-six cases(44.2%) expressed NIS in the differentiated thyroid and 63 cases(36.6%) were positive for CTCs in the peripheral blood. There was a significant difference between N0 and N1 in the expression of NIS(χ~2 = 6.015, P = 0.014) and the positive rate of CTCs(χ~2 = 14.035, P = 0.001). N0 and N1 also differed significantly in the expression of NIS(r =-0.383,-0.610, P = 0.002, < 0.001). The differences in the NIS expression, but not in the positive rate of CTCs, were significant among the different pathological subtypes(χ~2 = 7.897, P = 0.005; χ~2 = 1.455, P = 0.228, respectively). There was a significant negative correlation between the highly differentiated type and intermediate differentiation type both in the expression of NIS and positive rate of CTCs(r =-0.591,-0.443, P < 0.001, P = 0.002). Conclusion There was a significant negative correlation between the expression of tissue NIS and positive rate of CTCs in the peripheral blood in DTC. The malignancy level and lymph node metastasis in differentiated thyroid carcinoma were negatively correlated with NIS expression and positively correlated with the positive rate of CTC.展开更多
To investigate the effect of cytokines (TNF-α, IFN-γ and IL-6) on the expression of sodi-um-iodide symporter(NIS) gene in breast cancer cell (MCF-7). Methods:The breast cancer cell was cultureds with negative contro...To investigate the effect of cytokines (TNF-α, IFN-γ and IL-6) on the expression of sodi-um-iodide symporter(NIS) gene in breast cancer cell (MCF-7). Methods:The breast cancer cell was cultureds with negative control culture or cultures with different concentrations of cytokines for 72 h. NIS germ mRNA in breast cancer cells cultured was determined by reverse transcriptase-polymerase chain reaction(RT-PCR). Results:Expression of sodium-iodide symporter mRNA can be found decreasing along with increasing the concentration of cytokine dose-depen-dently. Conchzs/on ~ Cytokine may play a role in iodide-uptake modulating in breast cancer cells by their effect on NIS germ expression.展开更多
Radioiodine i s a routine therapy for differentiated thyroid cancers.Non-thyroid cancers can intake radioiodine after transfection of the human sodium iodide symporter (hNIS) gene.The human telomerase reverse transcri...Radioiodine i s a routine therapy for differentiated thyroid cancers.Non-thyroid cancers can intake radioiodine after transfection of the human sodium iodide symporter (hNIS) gene.The human telomerase reverse transcriptase (hTERT) promoter,an excellent tumor-specific promoter,has potential value for targeted gene therapy of glioma.We used the hTERT promoter to drive the expression of the hNIS and human thyroid peroxidase (hTPO) gene as a primary step for testing the effects of radioiodine therapy on malignant glioma.The U87 and U251 cells were co-transfected with two adenoviral vectors,in which the hNIS gene had been coupled to the hTERT promoter and the hTPO gene had been coupled to the CMV promoter,respectively.Then,we performed Western blot,125I intake and efflux assays,and clonogenic assay with cancer cells.We also did 99mTc tumor imaging of nude mice models.After co-transfection with Ad-hTERT-hNIS and Ad-CMV-hTPO,glioma cells showed the 125I intake almost 1.5 times higher than cells transfected with Ad-hTERT-hNIS alone.Western blots revealed bands of approximately 70 kDa and 110 kDa,consistent with the hNIS and hTPO proteins.In clonogenic assay,approximately 90% of cotransfected cells were killed,compared to 50% of control cells after incubated with 37 MBq of 131I.These results demonstrated that radioiodine therapy was effective in treating malignant glioma cell lines following induction of tumor-specific iodide intake by the hTERT promoter-directed hNIS expression in vitro.Cotransfected hNIS and hTPO genes can result in increased intake and longer retention of radioiodine.Nude mice harboring xenografts transfected with Ad-hTERT-NIS can take 99mTc scans.展开更多
BACKGROUND A proportion of lung cancers show sodium/iodide symporter(NIS)expression.Lung cancers with NIS expression may uptake radioiodine(RAI)and show RAIavid lesions on RAI scan for differentiated thyroid cancer(DT...BACKGROUND A proportion of lung cancers show sodium/iodide symporter(NIS)expression.Lung cancers with NIS expression may uptake radioiodine(RAI)and show RAIavid lesions on RAI scan for differentiated thyroid cancer(DTC)surveillance.AIM To investigate the possibility of RAI uptake by lung cancer in a cohort with thyroid cancer.METHODS RAI-avid lung cancers were analyzed using a prospectively maintained database of patients with thyroid cancer who were registered at a medical center between December 1,1976 and May 28,2018.NIS expression in lung cancer was assessed using immunohistochemical staining.RESULTS Of the 5000 patients with thyroid cancer from the studied dataset,4602 had DTC.During follow-up,33 patients developed primary lung cancer.Of these patients,nine received an iodine-131(131I)scan within 1 year before the diagnosis of lung cancer.One of these nine lung cancers was RAI-avid.NIS expression was evaluated,and three of the eight available lung cancers revealed NIS expression.The proportions of lung cancer cells with NIS expression were 60%,15%,and 10%.The RAI-avid lung cancer had the highest level of expression(60%).The RAI-avid lung cancer had a spiculated border upon single-photon emission computed tomography/computed tomography,which led to an accurate diagnosis.CONCLUSION A proportion of lung cancer demonstrates NIS expression and is RAI-avid.Clinicians should be aware of this possibility in the interpretation of RAI scintigraphy.展开更多
Anaplastic thyroid cancer(ATC)is a rare but highly lethal disease.ATCs are resistant to standard therapies and are extremely difficult to manage.The stepwise cell dedifferentiation results in the impairment of the iod...Anaplastic thyroid cancer(ATC)is a rare but highly lethal disease.ATCs are resistant to standard therapies and are extremely difficult to manage.The stepwise cell dedifferentiation results in the impairment of the iodine-metabolizing machinery and the infeasibility of radioiodine treatment in ATC.Hence,reinducing iodine-metabolizing gene expression to restore radioiodine avidity is considered as a promising strategy to fight against ATC.In the present study,capsaicin(CAP),a natural potent transient receptor potential vanilloid type 1(TRPV1)agonist,was discovered to reinduce ATC cell differentiation and to increase the expression of thyroid transcription factors(TTFs including TTF-1,TTF-2,and PAX8)and iodine-metabolizing proteins,including thyroidstimulating hormone receptor(TSHR),thyroid peroxidase,and sodium iodine symporter(NIS),in two ATC cell lines,8505C and FRO.Strikingly,CAP treatment promoted NIS glycosylation and its membrane trafficking,resulting in a significant enhancement of radioiodine uptake of ATC cells in vitro.Mechanistically,CAP-activated TRPV1 channel and subsequently triggered Ca2þinflux,cyclic adenosine monophosphate(cAMP)generation,and cAMP-responsive element-binding protein(CREB)signal activation.Next,CREB recognized and bound to the promoter of SLC5A5 to facilitate its transcription.Moreover,the TRPV1 antagonist CPZ,the calcium chelator BAPTA,and the PKA inhibitor H-89 effectively alleviated the redifferentiation exerted by CAP,demonstrating that CAP might improve radioiodine avidity through the activation of the TRPV1–Ca2þ/cAMP/PKA/CREB signaling pathway.In addition,our study indicated that CAP might trigger a novel cascade to redifferentiate ATC cells and provide unprecedented opportunities for radioiodine therapy in ATC,bypassing canonical TSH–TSHR pathway.展开更多
Objective The present study investigated the sodium/iodide symporter mRNA expression in mouse lactating mammary gland cells under different iodine levels and the effects of thyroid-stimulating hormone(TSH),estradiol(E...Objective The present study investigated the sodium/iodide symporter mRNA expression in mouse lactating mammary gland cells under different iodine levels and the effects of thyroid-stimulating hormone(TSH),estradiol(E2)and prolactin(PRL)on NIS mRNA expression in mouse lactating mammary gland cells.展开更多
Background The sodium-iodide symporter （NIS） protein can mediate the active radioiodine uptake.The human telomerase reverse transcriptase （hTERT） promoter is known to be selectively reactivated in majority of tumo...Background The sodium-iodide symporter （NIS） protein can mediate the active radioiodine uptake.The human telomerase reverse transcriptase （hTERT） promoter is known to be selectively reactivated in majority of tumors and hence could be used for tumor targeting.We constructed a recombinant adenovirus containing the human sodium iodide symporter （hNIS） gene directed by the hTERT promoter, characterized the ability of infected cells in uptaking iodide, and explored the therapeutic efficacy of 131I in a lung cancer cell line in vitro.Methods The hTERT promoter was amplified by PCR from DNA isolated from log-phase HepG2 cells, subcloned into lineralized FL＊-hNIS/pcDNA3, and then the hTERT-hNIS sequence was subcloned into the shuttle plasmid pAdTrack.The recombinant adenovirus Ad-hTERT-hNIS was constructed by AdEasy system.A positive control adenovirusAd-CMV-hNIS and a negative control adenovirus Ad-CMV were created similarly.A549 cells were transduced with recombinant adenoviruses.125I uptake studies and sodium perchlorate suppression studies were used to confirm hNIS expression and function.Toxic effects of 131I on tumor cells were studied by in vitro clonogenic assay.Results We first successfully constructed an adenovirus mediated transgene expression system of the hNIS under the control of hTERT promoter.When infected with recombinant adenovirus constructs expressing hNIS directed by hTERTand CMV-promoters （Ad-hTERT-hNIS and Ad-CMV-hNIS, respectively）, the lung cancer cell line A549 had increased ability to uptake radioiodide up to 23- and 30- fold compared to the control parental cells, respectively.The radioiodide uptake ability of both the Ad-CMV-hNIS and Ad-hTERT-hNIS transduced cell lines were repressed 11-fold by sodium perchlorate （NaCIO4）.The subsequent in vitro clonogenic assay of the infected A549 cell line was further repressed to 23% （Ad-CMV-hNIS） and 30% （Ad-hTERT-hNIS） of the control group after receiving radioiodide for 7 hours （P 〈0.001）.Conclusion Our preliminary study indicates that an adenovirus mediated transgene expression system of the hNIS under the control of hTERT promoter has the potential to become an effective wide-spectrum yet highly specific anti-cancer strategy.展开更多
文摘Radioiodine therapy, the most effective form of systemic radiotherapy available, is currently useful only for thyroid cancer because of the thyroid-specific expression of the human sodium iodide symporter （hNIS）. Here, we explore the efficacy of a novel form of gene therapy using prostate-specific membrane antigen （PSMA） promoter-mediated hNIS gene transfer followed by radioiodine administration for the treatment of castration-resistant prostate cancer （CRPC）. The androgen-dependent C33 LNCaP cell line and the androgen-independent C81 LNCaP cell line were transfected by adenovirus. PSMA promoter-hNIS （Ad.PSMApro-hNIS） or adenovirus.cytomegalovirus-hNIS containing the cytomegalovirus promoter （Ad.CMM-hNIS） or a control virus. The iodide uptake was measured in vitro. The in vivo iodide uptake by C81 cell xenografts in nude mice injected with an adenovirus carrying the hNIS gene linked to PSMA and the corresponding tumor volume fluctuation were assessed. Iodide accumulation was shown in different LNCaP cell lines after Ad.PSMApro-hNIS and Ad.CMV-hNIS infection, but not in different LNCaP cell lines after adenovirus.cytomegalovirus （Ad.CMV） infection. At each time point, higher iodide uptake was shown in the C81 cells infected with Ad.PSMApro-hNIS than in the C33 cells （P 〈 0.05）. An in vivo animal model showed a significant difference in 1311 radioiodine uptake in the tumors infected with Ad.PSMApro-hNIS, Ad.CMV-hNIS and control virus （P 〈 0.05） and a maximum reduction of tumor volume in mice infected with Ad.PSMApro-hNIS. These results show prostate-specific expression of the hNIS gene delivered by the PSMA promoter and effective radioiodine therapy of CRPC by the PSMA promoter-driven hNIS transfection.
基金Supported by National Natural Science Foundation of China (No.30900375)Shanghai Leading Academic Discipline Project (No.S30203)Medical Engineering (Science) Cross micro PET Special Foundation of Shanghai Jiaotong University (No.YG08PETZD01)
文摘To investigate human sodium/iodide symporter (hNIS) induced iodine uptake in human lung adenocarcinoma via baculovirus, a recombinant baculovirus encoding hNIS gene was constructed under the control of CMV promoter (Bac-CMV-hNIS). In vitro, baculovirus infected A549 cells accumulated about 27 times more 125I than that of noninfected cells. The 125I uptake was maximal after 30-min incubation of the cells, and efflux of the radioactivity was rapid, with 50% lost during the first 2 min after 125I-containing medium had been replaced by nonradioactive medium. Competition experiments in the presence of sodium perchlorate revealed a dose-dependent decrease of 125I uptake. Bac-CMV-hNIS infected tumor cells were selectively killed by exposure to 131I, as revealed by clonogenic assays. In nude mice, Bac-CMV-hNIS infected A549 cells accumulated more 131I than that of the control monitored by 1-h scintigraphy after 131I administration. The transduction of hNIS gene through baculovirus is sufficient to induce iodine transporting in A549 cells in vitro and in vivo, outlining the potential of this novel tumor gene imaging approach. But a rapid efflux of radioactivity from the tumor was shown in vivo and the in vivo therapy test showed no sign of effect.
基金Supported by a grant from the Gansu Province Key Traditional Chinese Medicine Project(No.GZK-2010-Z9)
文摘Objective We investigated the correlation between the expression of the sodium-iodide symporter(NIS) and the detection of circulating tumor cells(CTCs) in differentiated thyroid carcinoma(DTC).Methods NIS expression in differentiated thyroid and the positive rate of CTCs in the peripheral blood were determined by immunohistochemistry S-P and flow cytometry from the records of 172 cases of differentiated thyroid carcinoma.Results Seventy-six cases(44.2%) expressed NIS in the differentiated thyroid and 63 cases(36.6%) were positive for CTCs in the peripheral blood. There was a significant difference between N0 and N1 in the expression of NIS(χ~2 = 6.015, P = 0.014) and the positive rate of CTCs(χ~2 = 14.035, P = 0.001). N0 and N1 also differed significantly in the expression of NIS(r =-0.383,-0.610, P = 0.002, < 0.001). The differences in the NIS expression, but not in the positive rate of CTCs, were significant among the different pathological subtypes(χ~2 = 7.897, P = 0.005; χ~2 = 1.455, P = 0.228, respectively). There was a significant negative correlation between the highly differentiated type and intermediate differentiation type both in the expression of NIS and positive rate of CTCs(r =-0.591,-0.443, P < 0.001, P = 0.002). Conclusion There was a significant negative correlation between the expression of tissue NIS and positive rate of CTCs in the peripheral blood in DTC. The malignancy level and lymph node metastasis in differentiated thyroid carcinoma were negatively correlated with NIS expression and positively correlated with the positive rate of CTC.
文摘To investigate the effect of cytokines (TNF-α, IFN-γ and IL-6) on the expression of sodi-um-iodide symporter(NIS) gene in breast cancer cell (MCF-7). Methods:The breast cancer cell was cultureds with negative control culture or cultures with different concentrations of cytokines for 72 h. NIS germ mRNA in breast cancer cells cultured was determined by reverse transcriptase-polymerase chain reaction(RT-PCR). Results:Expression of sodium-iodide symporter mRNA can be found decreasing along with increasing the concentration of cytokine dose-depen-dently. Conchzs/on ~ Cytokine may play a role in iodide-uptake modulating in breast cancer cells by their effect on NIS germ expression.
基金supported by a grant from Tianjin Basic Research and Leading Edge Science Project of China (No. 08JCZDJC23900)
文摘Radioiodine i s a routine therapy for differentiated thyroid cancers.Non-thyroid cancers can intake radioiodine after transfection of the human sodium iodide symporter (hNIS) gene.The human telomerase reverse transcriptase (hTERT) promoter,an excellent tumor-specific promoter,has potential value for targeted gene therapy of glioma.We used the hTERT promoter to drive the expression of the hNIS and human thyroid peroxidase (hTPO) gene as a primary step for testing the effects of radioiodine therapy on malignant glioma.The U87 and U251 cells were co-transfected with two adenoviral vectors,in which the hNIS gene had been coupled to the hTERT promoter and the hTPO gene had been coupled to the CMV promoter,respectively.Then,we performed Western blot,125I intake and efflux assays,and clonogenic assay with cancer cells.We also did 99mTc tumor imaging of nude mice models.After co-transfection with Ad-hTERT-hNIS and Ad-CMV-hTPO,glioma cells showed the 125I intake almost 1.5 times higher than cells transfected with Ad-hTERT-hNIS alone.Western blots revealed bands of approximately 70 kDa and 110 kDa,consistent with the hNIS and hTPO proteins.In clonogenic assay,approximately 90% of cotransfected cells were killed,compared to 50% of control cells after incubated with 37 MBq of 131I.These results demonstrated that radioiodine therapy was effective in treating malignant glioma cell lines following induction of tumor-specific iodide intake by the hTERT promoter-directed hNIS expression in vitro.Cotransfected hNIS and hTPO genes can result in increased intake and longer retention of radioiodine.Nude mice harboring xenografts transfected with Ad-hTERT-NIS can take 99mTc scans.
基金Chang Gung Memorial Hospital,No.CMRPG3J0471and US NIH/NCI Cancer Center Support Grant,No.P30 CA008748.
文摘BACKGROUND A proportion of lung cancers show sodium/iodide symporter(NIS)expression.Lung cancers with NIS expression may uptake radioiodine(RAI)and show RAIavid lesions on RAI scan for differentiated thyroid cancer(DTC)surveillance.AIM To investigate the possibility of RAI uptake by lung cancer in a cohort with thyroid cancer.METHODS RAI-avid lung cancers were analyzed using a prospectively maintained database of patients with thyroid cancer who were registered at a medical center between December 1,1976 and May 28,2018.NIS expression in lung cancer was assessed using immunohistochemical staining.RESULTS Of the 5000 patients with thyroid cancer from the studied dataset,4602 had DTC.During follow-up,33 patients developed primary lung cancer.Of these patients,nine received an iodine-131(131I)scan within 1 year before the diagnosis of lung cancer.One of these nine lung cancers was RAI-avid.NIS expression was evaluated,and three of the eight available lung cancers revealed NIS expression.The proportions of lung cancer cells with NIS expression were 60%,15%,and 10%.The RAI-avid lung cancer had the highest level of expression(60%).The RAI-avid lung cancer had a spiculated border upon single-photon emission computed tomography/computed tomography,which led to an accurate diagnosis.CONCLUSION A proportion of lung cancer demonstrates NIS expression and is RAI-avid.Clinicians should be aware of this possibility in the interpretation of RAI scintigraphy.
基金supported by grants from the National Natural Science Foundation of China(81972503 and 82103656).
文摘Anaplastic thyroid cancer(ATC)is a rare but highly lethal disease.ATCs are resistant to standard therapies and are extremely difficult to manage.The stepwise cell dedifferentiation results in the impairment of the iodine-metabolizing machinery and the infeasibility of radioiodine treatment in ATC.Hence,reinducing iodine-metabolizing gene expression to restore radioiodine avidity is considered as a promising strategy to fight against ATC.In the present study,capsaicin(CAP),a natural potent transient receptor potential vanilloid type 1(TRPV1)agonist,was discovered to reinduce ATC cell differentiation and to increase the expression of thyroid transcription factors(TTFs including TTF-1,TTF-2,and PAX8)and iodine-metabolizing proteins,including thyroidstimulating hormone receptor(TSHR),thyroid peroxidase,and sodium iodine symporter(NIS),in two ATC cell lines,8505C and FRO.Strikingly,CAP treatment promoted NIS glycosylation and its membrane trafficking,resulting in a significant enhancement of radioiodine uptake of ATC cells in vitro.Mechanistically,CAP-activated TRPV1 channel and subsequently triggered Ca2þinflux,cyclic adenosine monophosphate(cAMP)generation,and cAMP-responsive element-binding protein(CREB)signal activation.Next,CREB recognized and bound to the promoter of SLC5A5 to facilitate its transcription.Moreover,the TRPV1 antagonist CPZ,the calcium chelator BAPTA,and the PKA inhibitor H-89 effectively alleviated the redifferentiation exerted by CAP,demonstrating that CAP might improve radioiodine avidity through the activation of the TRPV1–Ca2þ/cAMP/PKA/CREB signaling pathway.In addition,our study indicated that CAP might trigger a novel cascade to redifferentiate ATC cells and provide unprecedented opportunities for radioiodine therapy in ATC,bypassing canonical TSH–TSHR pathway.
文摘Objective The present study investigated the sodium/iodide symporter mRNA expression in mouse lactating mammary gland cells under different iodine levels and the effects of thyroid-stimulating hormone(TSH),estradiol(E2)and prolactin(PRL)on NIS mRNA expression in mouse lactating mammary gland cells.
基金This work was supported by Project of Natural Science Foundation of Jiangsu Province （NO. BK2008164）.
文摘Background The sodium-iodide symporter （NIS） protein can mediate the active radioiodine uptake.The human telomerase reverse transcriptase （hTERT） promoter is known to be selectively reactivated in majority of tumors and hence could be used for tumor targeting.We constructed a recombinant adenovirus containing the human sodium iodide symporter （hNIS） gene directed by the hTERT promoter, characterized the ability of infected cells in uptaking iodide, and explored the therapeutic efficacy of 131I in a lung cancer cell line in vitro.Methods The hTERT promoter was amplified by PCR from DNA isolated from log-phase HepG2 cells, subcloned into lineralized FL＊-hNIS/pcDNA3, and then the hTERT-hNIS sequence was subcloned into the shuttle plasmid pAdTrack.The recombinant adenovirus Ad-hTERT-hNIS was constructed by AdEasy system.A positive control adenovirusAd-CMV-hNIS and a negative control adenovirus Ad-CMV were created similarly.A549 cells were transduced with recombinant adenoviruses.125I uptake studies and sodium perchlorate suppression studies were used to confirm hNIS expression and function.Toxic effects of 131I on tumor cells were studied by in vitro clonogenic assay.Results We first successfully constructed an adenovirus mediated transgene expression system of the hNIS under the control of hTERT promoter.When infected with recombinant adenovirus constructs expressing hNIS directed by hTERTand CMV-promoters （Ad-hTERT-hNIS and Ad-CMV-hNIS, respectively）, the lung cancer cell line A549 had increased ability to uptake radioiodide up to 23- and 30- fold compared to the control parental cells, respectively.The radioiodide uptake ability of both the Ad-CMV-hNIS and Ad-hTERT-hNIS transduced cell lines were repressed 11-fold by sodium perchlorate （NaCIO4）.The subsequent in vitro clonogenic assay of the infected A549 cell line was further repressed to 23% （Ad-CMV-hNIS） and 30% （Ad-hTERT-hNIS） of the control group after receiving radioiodide for 7 hours （P 〈0.001）.Conclusion Our preliminary study indicates that an adenovirus mediated transgene expression system of the hNIS under the control of hTERT promoter has the potential to become an effective wide-spectrum yet highly specific anti-cancer strategy.
