Tunicamycin as a Novel Redifferentiation Agent in Radioiodine Therapy for Anaplastic Thyroid Cancer.

The silencing of thyroid-related genes presents difficulties in radioiodine therapy for anaplastic thyroid cancers (ATCs). Tunicamycin (TM), an N-linked glycosylation inhibitor, is an anticancer drug. Herein, we investigated TM-induced restoration of responsiveness to radioiodine therapy in radioiodine refractory ATCs. 125I uptake increased in TM-treated ATC cell lines, including BHT101 and CAL62, which was inhibited by KClO4, a sodium-iodide symporter (NIS) inhibitor. TM upregulated the mRNA expression of iodide-handling genes and the protein expression of NIS. TM blocked pERK1/2 phosphorylation in both cell lines, but AKT (protein kinase B) phosphorylation was only observed in CAL62 cells. The downregulation of glucose transporter 1 protein was confirmed in TM-treated cells, with a significant reduction in 18F-fluorodeoxyglucose (FDG) uptake. A significant reduction in colony-forming ability and marked tumor growth inhibition were observed in the combination group. TM was revealed to possess a novel function as a redifferentiation inducer in ATC as it induces the restoration of iodide-handling gene expression and radioiodine avidity, thereby facilitating effective radioiodine therapy.

Visualization of the Biological Behavior of Tumor-Associated Macrophages in Living Mice with Colon Cancer Using Multimodal Optical Reporter Gene Imaging.

We sought to visualize the migration of tumor-associated macrophages (TAMs) to tumor lesions and to evaluate the effects of anti-inflammatory drugs on TAM-modulated tumor progression in mice with colon cancer using a multimodal optical reporter gene system. Murine macrophage Raw264.7 cells expressing an enhanced firefly luciferase (Raw/effluc) and murine colon cancer CT26 cells coexpressing Rluc and mCherry (CT26/Rluc-mCherry, CT26/RM) were established. CT26/RM tumor-bearing mice received Raw/effluc via their tail veins, and combination of bioluminescence imaging (BLI) and fluorescence imaging (FLI) was conducted for in vivo imaging of TAMs migration and tumor progression. Dexamethasone (DEX), a potent anti-inflammatory drug, was administered intraperitoneally to tumor-bearing mice following the intravenous transfer of Raw/effluc cells. The migration of TAMs and tumor growth was monitored by serial FLI and BLI. The migration of Raw/effluc cells to tumor lesions was observed at day 1, and BLI signals were still distinct at tumor lesions on day 4. Localization of BLI signals from migrated Raw/effluc cells corresponded to that of FLI signals from CT26/RM tumors. In vivo FLI of tumors demonstrated enhanced tumor growth associated with macrophage migration to tumor lesions. Treatment with DEX inhibited the influx of Raw/effluc cells to tumor lesions and abolished the enhanced tumor growth associated with macrophage migration. These findings suggest that molecular imaging approach for TAM tracking is a valuable tool for evaluating the role of TAMs in the tumor microenvironment as well as for the development of new drugs to control TAM involvement in the modulation of tumor progression.

Corrigendum to "Visualization of the Biological Behavior of Tumor-Associated Macrophages in Living Mice with Colon Cancer Using Multimodal Optical Reporter Gene Imaging" [Neoplasia 18 (2016) 133-141].

[This corrects the article DOI: 10.1016/j.neo.2016.01.004.].

Inverse Agonist of Estrogen-Related Receptor γ Enhances Sodium Iodide Symporter Function Through Mitogen-Activated Protein Kinase Signaling in Anaplastic Thyroid Cancer Cells.

UNLABELLED: Anaplastic thyroid cancer (ATC), a rare thyroid cancer with poor prognosis, is associated with insufficient function of the sodium iodide symporter (NIS). Estrogen-related receptor γ (ERRγ) is a member of the orphan nuclear receptors with important functions in cell development and homeostasis. However, there are no reports that demonstrate whether ERRγ is related to NIS function. Here, we evaluated the role of ERRγ in the regulation of NIS function in ATC cells using GSK5182, an inverse agonist of ERRγ. METHODS: Two ATC cell lines, BHT-101 and CAL62, were incubated with GSK5182 at various time points and doses. The NIS function in the ATC cells was serially assessed by their uptake of radioiodine. The effects of GSK5182 on ERRγ and the mitogen-activated protein (MAP) kinase pathway, as well as on NIS protein, were evaluated by immunoblot assay. To examine whether the GSK5182-induced NIS functional activity can be affected by inhibition of the MAP kinase pathway, the MAP kinase activity and levels of radioiodine uptake were determined after application of a mitogen-activated protein kinase kinase (MEK) inhibitor to GSK5182-treated cells. Finally, the cytotoxic effect of (131)I was determined by clonogenic assay. RESULTS: Treatment with GSK5182 resulted in dose- and time-dependent increases in iodide uptake in ATC cells, which were accompanied by both the downregulation of ERRγ protein and the activation of extracellular signal-regulated kinase (ERK) 1/2. Both the increased radioiodine uptake and ERK1/2 activation of ATC cells were completely inhibited by the specific MEK inhibitor. GSK5182 treatment enhanced the membrane localization of NIS in both ATC cell lines. Accordingly, preexposure to GSK5182 enhanced the cytotoxic effects of (131)I treatment in ATC cells. CONCLUSION: These findings suggest that the inverse agonist of ERRγ enhances the responsiveness of radioiodine therapy by modulating NIS function in ATC cells via the regulation of ERRγ and the MAP kinase signaling pathway.

Tracking of dendritic cell migration into lymph nodes using molecular imaging with sodium iodide symporter and enhanced firefly luciferase genes.

We sought to evaluate the feasibility of molecular imaging using the human sodium iodide symporter (hNIS) gene as a reporter, in addition to the enhanced firefly luciferase (effluc) gene, for tracking dendritic cell (DCs) migration in living mice. A murine dendritic cell line (DC2.4) co-expressing hNIS and effluc genes (DC/NF) was established. For the DC-tracking study, mice received either parental DCs or DC/NF cells in the left or right footpad, respectively, and combined I-124 PET/CT and bioluminescence imaging (BLI) were performed. In vivo PET/CT imaging with I-124 revealed higher activity of the radiotracer in the draining popliteal lymph nodes (DPLN) of the DC/NF injection site at day 1 than DC injection site (p < 0.05). The uptake value further increased at day 4 (p < 0.005). BLI also demonstrated migration of DC/NF cells to the DPLNs at day 1 post-injection, and signals at the DPLNs were much higher at day 4. These data support the feasibility of hNIS reporter gene imaging in the tracking of DC migration to lymphoid organs in living mice. DCs expressing the NIS reporter gene could be a useful tool to optimize various strategies of cell-based immunotherapy.

Combined Fluorescence and Magnetic Resonance Imaging of Primary Macrophage Migration to Sites of Acute Inflammation Using Near-Infrared Fluorescent Magnetic Nanoparticles.

PURPOSE: This study aimed to track the migration of primary macrophages labeled with near-infrared (NIR) fluorescent magnetic nanoparticles toward chemically induced acute inflammatory lesions in mice and to visualize the effect of anti-inflammatory drugs on macrophage migration using combined fluorescence and magnetic resonance imaging (FLI/MRI). PROCEDURES: Primary macrophages were labeled with NIR fluorescent magnetic nanoparticles, and labeled cells were injected into mice intravenously. One day later, inflammation was induced by subcutaneous injection of 1% carrageenan (CG) solution to footpads of the right hind leg, and phosphate-buffered saline (PBS) as control treatment was subcutaneously injected to footpad of the left hind leg. To evaluate the effect of drug treatment on macrophage migration, a single dose of dexamethasone (DEX) was intraperitoneally administered to the mice immediately after the induction of inflammation and was followed by combined FLI/MRI at predetermined time points. RESULTS: No difference in cellular viability or phagocytic activity was observed between the labeled and parent macrophages. In vivo optical imaging revealed an increase in FLI signals in CG-injected footpads in a time-dependent manner, but not in PBS-treated footpads. DEX treatment inhibited the migration of the labeled macrophages to the CG-injected footpads, with relative decreases in FLI activity. In accordance with FLI, T2*-weighted MR images showed hypo-intense signals in the CG-injected footpads but not in the PBS-injected footpads. The DEX-treated mice did not show a dark signal loss zone on MR images in the CG-treated paw. CONCLUSIONS: We successfully tracked the migration of macrophages to inflammatory lesions using both FLI and MRI with NIR fluorescent magnetic nanoparticles and demonstrated the inhibitory effects of DEX on macrophage migration to inflammation sites.

Noninvasive imaging of apoptosis induced by adenovirus-mediated cancer gene therapy using a caspase-3 biosensor in living subjects.

We attempted to visualize the serial induction of caspase-3-dependent apoptosis mediated by Fas ligand/tumor necrosis factor-related apoptosis-inducing ligand (FasL/TRAIL) adenoviral gene therapy in mice bearing human glioma xenografts using a caspase-3 biosensor and monitored its therapeutic effects. Human D54 glioma cells expressing both the caspase-3 sensor and the Renilla luciferase (Rluc) gene were established (referred to as D54-CR cells). The bioluminescence imaging (BLI) signals of the caspase-3 sensor in the D54-CR cells were increased in a time- and virus dose-dependent manner by Ad-TRAIL or Ad-FasL transduction. Fluorescence-activated cell sorting (FACS) analysis revealed an increase in both cleaved caspase-3 or poly(ADP-ribose) polymerase (PARP) and annexin V- and propidium iodide-positive cells depending on the dosage of administered virus. Ad-FasL treatment resulted in a significant increase in the BLI activity of the caspase-3 sensor in the D54-CR tumors, which were ≈ 8.2, ≈ 12.9, and ≈ 46.6 times higher than those of control at 12 hours, 24 hours, and 96 hours posttreatment, respectively. In contrast, a significant reduction in Rluc activity, as a surrogate marker of cell viability, was detected in the tumors treated with Ad-FasL but not in those treated with Ad-null. Overall, the activation of caspase-3-dependent apoptosis induced by Ad-FasL/Ad-TRAIL gene therapy was successfully monitored by a sensitive imaging platform for caspase-3 activation.

Evaluation of therapeutic effects of natural killer (NK) cell-based immunotherapy in mice using in vivo apoptosis bioimaging with a caspase-3 sensor.

Natural killer (NK) cell-based immunotherapy is a promising strategy for cancer treatment, and caspase-3 is an important effector molecule in NK cell-mediated apoptosis in cancers. Here, we evaluated the antitumor effects of NK cell-based immunotherapy by serial noninvasive imaging of apoptosis using a caspase-3 sensor in mice with human glioma xenografts. Human glioma cells expressing both a caspase-3 sensor as a surrogate marker for caspase-3 activation and Renilla luciferase (Rluc) as a surrogate marker for cell viability were established and referred to as D54-CR cells. Human NK92 cells were used as effector cells. Treatment with NK92 cells resulted in a time- and effector number-dependent increase in bioluminescence imaging (BLI) activity of the caspase-3 sensor in D54-CR cells in vitro. Caspase-3 activation by NK92 treatment was blocked by Z-VAD treatment in D54-CR cells. Transfusion of NK92 cells induced an increase of the BLI signal by caspase-3 activation in a dose- and time-dependent manner in D54-CR tumor-bearing mice but not in PBS-treated mice. Accordingly, sequential BLI with the Rluc reporter gene revealed marked retardation of tumor growth in the NK92-treatment group but not in the PBS-treatment group. These data suggest that noninvasive imaging of apoptosis with a caspase-3 sensor can be used as an effective tool for evaluation of therapeutic efficacy as well as for optimization of NK cell-based immunotherapy.-Lee, H. W., Singh, T. D., Lee, S.-W., Ha, J.-H., Rehemtulla, A., Ahn, B.-C., Jeon, Y.-H., Lee, J. Evaluation of therapeutic effects of natural killer (NK) cell-based immunotherapy in mice using in vivo apoptosis bioimaging with a caspase-3 sensor.

Dual reporter gene imaging for tracking macrophage migration using the human sodium iodide symporter and an enhanced firefly luciferase in a murine inflammation model.

PURPOSE: The purpose of this study is to visualize the migration of reporter macrophages expressing both the human sodium iodide symporter (hNIS) and enhanced firefly luciferase (effluc) gene in mice with chemically induced inflammation. PROCEDURES: A macrophage cell line expressing both hNIS and effluc genes (Raw264.7/hNIS-effluc, herein referred to as a Raw264.7/NF) was established by cotransduction of two genes into a murine macrophage cell line (Raw264.7), and cell proliferation and phagocytic activity were compared between parental Raw264.7 and Raw264.7/NF cells. Both serial bioluminescence imaging (BLI) and small animal positron emission tomography (PET) imaging with I-124 were performed in inflammation-induced mice at various time points after intravenous injection of either Raw264.7 or Raw264.7/NF cells. RESULTS: There was no significant difference in cellular proliferation and phagocytic activity between parental Raw264.7 and Raw264.7/NF cells. Early distribution of Raw264.7/NF cells was successfully visualized in the lung and spleen by BLI, but not by I-124 PET imaging. BLI signals, but not PET signals, were observed from the inflammation site at day 4 after the injection of Raw264.7/NF cells, and the signal intensity gradually increased until day 8. In contrast, focal uptake of I-124 was first detected at the site of inflammation at postinjection day 8, and signal intensity from the inflamed lesion was highest at that time point. While visualization of the inflamed lesion was possible by both BLI and PET imaging until day 14, it was only possible by BLI until day 21 after injection. CONCLUSIONS: Tracking of macrophage migration toward inflammation foci was successfully achieved in vivo from early time points by dual reporter gene imaging with a combination of nuclear and optical reporters. Multimodal reporter imaging of macrophages might successfully overcome the limitations of single reporter gene imaging in preclinical models of inflammation.

Effects of single treatment of anti-dementia drugs on sleep-wake patterns in rats.

We studied the effects of acetylcholinesterase inhibitors, donepezil and galantamine, and an N-methyl-D-aspartate (NMDA) receptor blocker, memantine, on sleep-wake architecture in rats. Screw electrodes were chronically implanted into the frontal and parietal cortex for the electroencephalography (EEG). EEG was recorded with a bio-potential amplifier for 8 h from 09:30 to 17:30. Vibration was recorded to monitor animal activity with a vibration measuring device. Sleep-wake states such as wake (W), slow-wave sleep (S) and paradoxical or rapid eye movement sleep (P), were scored every 10 sec by an experimenter. We measured mean episode duration and number of episode to determine which factor sleep disturbance was attributed to. Donepezil and memantine showed a significant increase in total W duration and decreases in total S and P duration and delta activity. Memantine showed increases in sleep latency and motor activity. Changes of S and P duration in memantine were attributed from changes of mean episode duration. Galantamine had little effect on sleep architecture. From these results, it is showed that galantamine may be an anti-dementia drug that does not cause sleep disturbances and memantine may be a drug that causes severe sleep disturbance.

L-theanine partially counteracts caffeine-induced sleep disturbances in rats.

L-theanine has been reported to inhibit the excitatory effects of caffeine. The present study examined the effects of L-theanine on caffeine-induced sleep disturbances in rats. Rats received the following drug pairings: saline and saline (Control), 7.5 mg/kg caffeine and saline, or 7.5 mg/kg of caffeine followed by various doses of L-theanine (22.5, 37.5, 75, or 150 mg/kg). Vigilance states were divided into: wakefulness (W), transition to slow-wave sleep (tSWS), slow-wave sleep (SWS), and rapid-eye-movement sleep (REMS). Caffeine significantly increased the duration of W and decreased the duration of SWS and REMS compared to the Control. Although L-theanine failed to reverse the caffeine-induced W increase, at 22.5 and 37.5 mg/kg (but not at 75 and 150 mg/kg), it significantly reversed caffeine-induced decreases in SWS. In conclusion, low doses of L-theanine can partially reverse caffeine-induced reductions in SWS; however, effects of L-theanine on caffeine-induced insomnia do not appear to increase dose-dependently.

Enhanced antiproliferative effects of combination hexokinase II shRNA and NIS gene therapy on vascular smooth muscle cells.

INTRODUCTION: This study was designed to determine the antiproliferative effects of combination gene therapy using sodium iodide symporter (NIS)-based radioiodine and lentivirus-mediated short hairpin RNA (shRNA) against hexokinase II (HKII) on vascular smooth muscle cells (VSMCs). METHODS: A7r5 rat VSMCs were stably transfected with a dual-expression vector of NIS and Fluc (A7r5-NL cells). Functional assessment was performed by radioiodine uptake assay, luciferase assay and confocal microscopy. After exposure to lentivirus-HKII-shRNA, the (18)F-FDG uptake test and HK activity assay were performed. The effects of combination therapy with (131)I and lentivirus-HKII-shRNA on VSMCs were assessed with an in vitro clonogenic assay. In vivo bioluminescence and nuclear imaging were undertaken using a xenografted mouse model. RESULTS: In vitro functional assessment confirmed expression of NIS and Fluc genes in A7r5-NL, but not in parent A7r5 cells. Transfection of lentivirus-HKII-shRNA resulted in a significant decrease in messenger RNA expression of the HKII gene, (18)F-FDG uptake and HK activity. The cell survival rate of A7r5-NL decreased to 61.9% and 90.5% by single therapy with 7.4 MBq of (131)I or lentivirus-HKII-shRNA, respectively, and further decreased to 42.9% by combined therapy (P<.05). In vivo bioluminescent and gamma camera images clearly demonstrated optical signals and (99m)Tc pertechnetate uptake at the site of A7r5-NL cell inoculation in nude mice. CONCLUSION: The enhanced antiproliferative effect on VSMCs was achieved by a combination of NIS-based radioiodine and lentivirus-mediated HKII shRNA gene therapy. Successful demonstration of in vivo dual reporter gene imaging assures the potential for further application in an animal model.

Combined E7-dendritic cell-based immunotherapy and human sodium/iodide symporter radioiodine gene therapy with monitoring of antitumor effects by bioluminescent imaging in a mouse model of uterine cervical cancer.

Using a uterine cervical cancer cell line expressing human papillomavirus (HPV) 16 E7 antigen and bioluminescent imaging (BLI), we evaluated the therapeutic potential of combined immunotherapy using transfected dendritic cells (DC-E7) and human sodium/iodide symporter (hNIS) radioiodine gene therapy in a xenograft animal cancer model. Dendritic cells expressing either E7 antigen (DC-E7) or no-insert (DC-no insert) were made for immunization materials, and murine uterine cervical cancer cell line coexpressing E7, firefly luciferase, hNIS, and EGFP genes (TC-1/FNG) were prepared for the animal tumor model. C57BL/6 mice were divided into five therapy groups (phosphate-buffered saline [PBS], DC-no insert, DC-E7, I-131, and DC-E7+I-131 groups). Single therapy with either DC-E7 or I-131 induced greater retardation in tumor growth compared with PBS or DC-no insert groups, and it resulted in some tumor-free mice (DC-E7 and I-131 groups, 40% and 20%, respectively). Combination therapy with DC-E7 and I-131 dramatically inhibited tumor growth, thus causing complete disappearance of tumors in all mice, and these effects were further confirmed by BLI in vivo. In conclusion, complete disappearance of the tumor was achieved with combined DC-E7 vaccination and hNIS radioiodine gene therapy in a mouse model with E7-expressing uterine cervical cancer, and serial BLIs successfully demonstrated antitumor effects in vivo.

Combined Cerenkov luminescence and nuclear imaging of radioiodine in the thyroid gland and thyroid cancer cells expressing sodium iodide symporter: initial feasibility study.

Radioiodine (RI) such as (131)I or (124)I, can generate luminescent emission and be detected with an optical imaging (OI) device. To evaluate the possibility of a novel Cerenkov luminescence imaging (CLI) for application in thyroid research, we performed feasibility studies of CLI by RI in the thyroid gland and human anaplastic thyroid carcinoma cells expressing sodium iodide symporter gene (ARO-NIS). For in vitro study, FRTL-5 and ARO-NIS were incubated with RI, and the luminometric and CLI intensity was measured with luminometer and OI device. Luminescence intensity was compared with the radioactivity measured with γ-counter. In vivo CLI of the thyroid gland was performed in mice after intravenous injection of RI with and without thyroid blocking. Mice were implanted with ARO-NIS subcutaneously, and CLI was performed with injection of (124)I. Small animal PET or γ-camera imaging was also performed. CLI intensities of thyroid gland and ARO-NIS were quantified, and compared with the radioactivities measured from nuclear images (NI). Luminometric assay and OI confirmed RI uptake in the cells in a dose-dependent manner, and luminescence intensity was well correlated with radioactivity of the cells. CLI clearly demonstrated RI uptake in thyroid gland and xenografted ARO-NIS cells in mice, which was further confirmed by NI. A strong positive correlation was observed between CLI intensity and radioactivity assessed by NI. We successfully demonstrated dual molecular imaging of CLI and NI using RI both in vitro and in vivo. CLI can provide a new OI strategy in preclinical thyroid studies.

Evaluation of the reversal of multidrug resistance by MDR1 ribonucleic acid interference in a human colon cancer model using a Renilla luciferase reporter gene and coelenterazine.

The reversal effect of multidrug resistance (MDR1) gene expression by adenoviral vector-mediated MDR1 ribonucleic acid interference was assessed in a human colon cancer animal model using bioluminescent imaging with Renilla luciferase (Rluc) gene and coelenterazine, a substrate for Rluc or MDR1 gene expression. A fluorescent microscopic examination demonstrated an increased green fluorescent protein signal in Ad-shMDR1- (recombinant adenovirus that coexpressed MDR1 small hairpin ribonucleic acid [shRNA] and green fluorescent protein) infected HCT-15/Rluc cells in a virus dose-dependent manner. Concurrently, with an increasing administered virus dose (0, 15, 30, 60, and 120 multiplicity of infection), Rluc activity was significantly increased in Ad-shMDR1-infected HCT-15/Rluc cells in a virus dose-dependent manner. In vivo bioluminescent imaging showed about 7.5-fold higher signal intensity in Ad-shMDR1-infected tumors than in control tumors (p < .05). Immunohistologic analysis demonstrated marked reduction of P-glycoprotein expression in infected tumor but not in control tumor. In conclusion, the reversal of MDR1 gene expression by MDR1 shRNA was successfully evaluated by bioluminescence imaging with Rluc activity using an in vivo animal model with a multidrug resistance cancer xenograft.

Trafficking macrophage migration using reporter gene imaging with human sodium iodide symporter in animal models of inflammation.

UNLABELLED: The aim of this study was to investigate the feasibility of nuclear molecular imaging using the human sodium iodide symporter (hNIS) as a reporter gene to monitor macrophage migration toward the inflammatory foci. METHODS: A stable macrophage cell line coexpressing hNIS and green fluorescent protein (GFP) genes (RAW264.7/hNIS-GFP and R(NIS) cell) was established from an immortalized macrophage cell line (RAW264.7 cells). (125)I uptake was determined (for hNIS protein functional activity), and flow cytometry analysis (to examine GFP gene expression), a cell proliferation assay, a cytokine assay, and a phagocytic activity assay were performed. (99m)Tc-pertechnetate images were acquired at 1 d after subcutaneous inoculation of R(NIS) cells in nude mice. Chemical inflammation was induced for in vivo imaging in the thigh of nude mice by turpentine oil injection. Small-animal PET with (18)F-FDG and (124)I was performed with an intravenous administration of RAW264.7 or R(NIS) cells in inflammation-induced animals. RESULTS: The expression of hNIS and GFP genes was confirmed in R(NIS) cells by flow cytometry and immunofluorescent staining. (125)I uptake was about 67 times higher in R(NIS) cells than in RAW264.7 cells. No significant difference was observed in cell proliferation, cytokine production, and phagocytic activity between RAW264.7 and R(NIS) cells. (99m)Tc-pertechnetate imaging revealed increased tracer uptake at the inoculation site. PET with (124)I demonstrated a donut-shaped uptake, correlating with uptake shown by the (18)F-FDG PET images, at the inflammation site of mice administered R(NIS) cells. (124)I uptake (percentage injected dose per gram) was about 2.12 times higher at the inflammation site in the R(NIS) mice than in RAW264.7 mice. By immunohistochemistry, the migration of macrophages was further confirmed by positive staining for GFP and hNIS at the inflammation site of R(NIS) mice. CONCLUSION: These data support the feasibility of hNIS reporter gene imaging to monitor the macrophage migration toward an inflammatory lesion. Macrophages expressing hNIS may provide a new strategy to investigate the cellular behavior seen with inflammatory response in a preclinical model.

Enhanced antitumor effects by combination gene therapy using MDR1 gene shRNA and HSV1-tk in a xenograft mouse model.

The use of a novel therapeutic vector containing HSV1-thymidine kinase (HSV1-tk) and a short hairpin RNA for the MDR1 gene (shMDR) was proposed previously. We investigated the antitumor effects in an in vivo mouse model of colon cancer and assessed treatment response by serial non-invasive imaging. shMDR-TK expressing (MTKG) tumors for the dual therapy group mice with ganciclovir and doxorubicin showed a decrease in size, while tumors in the single therapy group mice showed a moderate increase (p<0.05). The (131)I-5-iodo-2'-fluoro-2'deoxy-1-beta-d-arabinofuranosyluracil (FIAU) uptake ratio of MTKG-to-parent HCT-15 tumors decreased as treatment progressed for single or dual therapy group mice, while that of the control group mice increased gradually. This study demonstrates the enhanced antitumor effects with combination gene therapy compared with a single therapeutic approach, and provides the potential of therapeutic response monitoring.

Combined radionuclide-chemotherapy and in vivo imaging of hepatocellular carcinoma cells after transfection of a triple-gene construct, NIS, HSV1-sr39tk, and EGFP.

The sodium iodine symporter (NIS) or mutant Herpes-simplex virus type1 sr39 thymidine kinase (HSV1-sr39tk) gene is used for in vivo imaging and cancer therapy. Transfection of both NIS and HSV1-sr39tk genes to hepatocellular carcinoma cells (Huh-7/NTG) could enhance intracellular accumulation of therapeutic radionuclides and guanosine nucleoside analogue prodrugs to produce better outcomes than single gene therapy. Non-invasive imaging with I-124, F-18 FHBG and combination therapy with I-131 and GCV were performed in hepatocellular carcinoma cells transfected with NIS, HSV1-sr39tk and GFP. Our results show that: (1) all three genes are stably expressed in Huh-7/NTG cells, (2) I-125 and H3-PCV uptake were markedly increased in the Huh-7/NTG cells in vitro, (3) cellular survival and tumor growth of Huh-7/NTG was inhibited by I-131 or GCV both in vitro and in vivo, and was much prominent with combination therapy, (4) in vivo imaging with I-124 and F-18 FHBG revealed increased uptake in the Huh-7/NTG tumor. Our results demonstrated the potential of combination gene therapy using NIS and HSV1-sr39tk followed by radioiodine treatment and chemotherapy in human hepatocellular carcinoma cells.

Human sodium iodide symporter added to multidrug resistance 1 small hairpin RNA in a single gene construct enhances the therapeutic effects of radioiodine in a nude mouse model of multidrug resistant colon cancer.

The objective of this study was to investigate the therapeutic potential of ¹³¹I added to doxorubicin therapy in multidrug resistance (MDR) mouse colon cancer coexpressing the MDR1 small hairpin RNA (shRNA) and human sodium iodide symporter (hNIS) gene in a single gene construct and to visualize the antitumor effects using molecular nuclear imaging. HCT-15 coexpressing shRNA for MDR1 gene (MDR1 shRNA) and hNIS gene with a single construct was established (referred to as MN61 cell). Inhibition of P-gp function by MDR1 shRNA and functional activity of hNIS gene was assessed using a 99(m)Tc sestamibi uptake and ¹²5I uptake, respectively. Cytotoxic effects by a combination of doxorubicin and ¹³¹I were determined in parental (HCT-15) or MN61 cells using an in vitro clonogenic assay. Therapeutic effect of either combination therapy (doxorubicin and ¹³¹I) or single therapy (doxorubicin or ¹³¹I alone) was evaluated by tumor volume measurement. 99(m)Tc-sestamibi, ¹²³I, and 99(m)Tc-pertechnetate images of mice were acquired to evaluate functional assessment in vivo. Cellular uptake of 99(m)Tc-sestamibi and ¹²5I was approximately 2-fold and 100-fold higher in MN61 cells than in parental cells, respectively. Combination of ¹³¹I and doxorubicin resulted in higher cytotoxcity in MN61 cells as compared with parental cells. Scintigraphic imaging showed higher uptake of 99(m)Tc-sestamibi and ¹²³I in MN61 tumor as compared with parental tumor. In mice treated with doxorubicin, there was a slight delay in tumor growth in the MN61 tumor but not in the parental tumor. Cancer treatment with ¹³¹I or doxorubicin induced a rapid reduction of tumor volume in the MN61 tumor but not in the parental tumor. Combination therapy further generated a rapid reduction of tumor volume as compared with ¹³¹I therapy alone (p < 0.05). A combination hNIS mediated radioiodine gene therapy added to MDR1 shRNA treatment improved the effects of cancer treatment in a MDR cancer model and could enable visualization of the antitumor effects with nuclear imaging.