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Hepatocellular carcinoma (HCC) is one of the leading causes of mortality worldwide. The aim of the present study was to evaluate the distribution and the therapeutic effect of 188Re-Tin-colloid micro-particles in subcutaneous HCC-bearing mice. The synthesis and characterization of micro-particles labeled with the 188Re isotope were performed. The micro-particles were injected into the tumor site subcutaneously in the BNL HCC-bearing mice with three treatment groups, normal saline, 188Re micro-particles, and 188Re-Tin-colloid micro-particles. The results of biodistribution showed that major radioactivity (188Re) of 188Re-Tin-colloid micro-particles (18.69 ± 4.28 %ID/g) remained at the tumor sites, compared with 188Re micro-particles (0.21 ± 0.12 %ID/g), 24 h post injection. Following the injection of 188Re-Tin-colloid micro-particles for 14 days, all BNL tumors in mice were regressed during the observation period. By contrast, all of the mice treated with normal saline or 188Re micro-particles had died by 24 and 28 days, respectively. The 188Re-Tin-colloid micro-particles demonstrated high accumulation and therapeutic potential in the subcutaneous HCC-bearing mice.

Photodynamic therapy (PDT) is a treatment utilizing the combined action of photosensitizers and light for the treatment of various cancers. The mechanisms for tumor destruction after PDT include direct tumor cell kill by singlet oxygen species (OS), indirect cell kill via vascular damage, and an elicited immune response. However, it has been reported that many cellular activators, including vascular endothelial growth factor (VEGF), are produced by tumor cells after PDT. In this study, we demonstrate that meta-tetra(hydroxyphenyl) chlorin (mTHPC)-based photodynamic therapy combined with bevacizumab (Avastin™), an anti-VEGF neutralizing monoclonal antibody that blocks the binding of VEGF to its receptor, can enhance the effectiveness of each treatment modality. We evaluated the efficacy of bevacizumab-based anti-angiogenesis in combination with PDT as well as the resulting VEGF levels and microvessel density (MVD) in a mouse model of human colon cancer. Enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC) were performed to assess VEGF concentrations and microvessel density in the various treatment groups, and confocal imaging and high performance liquid chromatography (HPLC) analyses were used to measure the distribution and concentration of mTHPC in tumors. Our results demonstrate that combination of PDT followed by bevacizumab significantly elicits a greater tumor response whereas bevacizumab treatment prior to PDT led to a reduced tumor response. Immunostaining and ELISA analyses revealed a lower expression of VEGF in tumors treated with combination therapy of PDT followed by bevacizumab. However, bevacizumab treatment decreased the accumulation of mTHPC in tumors 24 h after administration, which complemented the results of decreased anti-tumor efficacy of bevacizumab followed by PDT.

To improve the effectiveness of cancer treatment, this study aimed to develop biodegradable microspheres and to combine chemotherapy and radiotherapy via transcatheter arterial embolization/chemoembolization (TAE/TACE) with local radiation therapy for the slow release of chemotherapeutic agents. Microparticles were prepared by double emulsification using a biodegradable and biocompatible polymer Poly(D,l-lactide-co-glycolide) (PLGA). Since the microspheres contain a water-soluble Poly(vinylsulfonic acid) (PVSA) solution, the functional groups of this polymer dissociate into −SO3– in water. The positively charged doxorubicin can be loaded into beads, ensuring slow release. After 188Retin colloids were added into the microspheres, TACE was performed in a rat hepatocellular carcinoma model. Single photon emission computed tomography/computed tomography imaging and biodistribution analyses showed that the microspheres were still in the liver after 72 h. During 4 weeks of observation, ultrasound images showed ...

BackgroundCancer stem cells (CSCs) are involved in drug resistance, metastasis, and relapse of cancers, which can significantly affect tumor therapy. Hence, to develop specifically therapeutic target probe at CSCs for improvement of survival and quality of life of cancer patients is urgently needed. The CD166 protein has been suggested to be involved in colorectal cancer (CRC) tumorigenesis and to be considered a marker for colorectal CSCs (CRCSCs) detection. In this study, therefore, we attend to apply a nuclear imaging agent probe, Glycine18-Cystine-linked CD166-targeted peptides (CD166tp-G18C), to detect the changes of CD166 level in a CRC xenograft mouse model.ResultsWe isolated the CD166-positive cells from the HCT15 CRC cell line (CD166+HCT15) and evaluated their morphology and ability of clone formation, migration, protein expression, and drug resistance. The CD166-positive HCT15 cells display the CSCs characteristics. We discovered and designed a CD166-targeted peptide (CD166tp-G18C) as a targeted probe of CRC stem-like cell for cell binding assay. The CD166tp-G18C confirmed the CD166 protein targeting ability in CD166+HCT15 cells. The diethylenetriaminopentaacetic acid (DTPA)-conjugated CD166tp-G18C further was labeled with indium-111 (111In-DTPA-CD166tp-G18C) as nuclear imaging agent for imaging and bio-distribution analysis in vivo. Finally, we observed that the111In-DTPA-CD166tp-G18C was significantly enhanced in tumor tissues of CD166+HCT15 xenograft mice as compared to the non-CD166tp-G18C control.ConclusionsOur results indicated that the indium-111-labeled CD166tp-G18C may be served as a powerful tool for colorectal CSCs nuclear imaging in the CRC patients.

Hypoxic microenvironment is a common situation in solid tumors. Carbonic anhydrase IX (CA9) is one of the reliable cellular biomarkers of hypoxia. The role of CA9 in colorectal cancer (CRC) remains to be clarified. CA9 inhibitor such as sulfonamides is known to block CA9 activation and reduce tumor growth consequently. Here, we aimed to investigate the CA9 expression in serum and tumor from different stages of CRC patients and utilize sulfonamide derivative with indium-111 labeling as a probe for CRC nuclear imaging detection in vivo. The serum CA9 was correlated with the tumor CA9 levels in different stages of CRC patients. Hypoxia increased cell viability and CA9 expression in colorectal cancer HCT-15 cells. Sulfonamide derivative 5-(2-aminoethyl)thiophene-2-sulfonamide (ATS) could bind with CA9 in vitro under hypoxia. Moreover, tumor tissues in HCT-15-induced xenograft mice possessed higher hypoxic fluorescence signal as compared with other organs. We also found that the radioisotope signal of indium-111 labeled ATS, which was utilized for CRC detection in HCT-15-induced xenograft mice, was markedly enhanced in tumors as compared with non-ATS control. Taken together, these findings suggest that CA9 is a potential hypoxic CRC biomarker and measurement of serum CA9 can be as a potential tool for diagnosing CA9 expressions in CRC clinical practice. The radioisotope-labeled sulfonamide derivative (ATS) may be useful to apply in CRC patients for nuclear medicine imaging.

Summary Background Statins are a class of drugs used to lower cholesterol levels, accompanying increased high-density lipoprotein (HDL) levels. Previous studies have suggested that statins can inhibit inflammation, and also reduce tumor proliferation. We therefore hypothesized that pravastatin, a member of the statins, mediating the inhibitory functions in tumor growth may be associated with the upregulated HDL constituent, apolipoprotein A1 (ApoA1). Methods Pravastatin-induced inhibition in tumor proliferation in vitro and in xenografts was investigated. Reduced ApoA1 expressions were detected in the tumor regions in specimens from tumor patients as well in xenografts using Western Blotting. Moreover, ApoA1 was administered to inhibit tumor proliferation, and pravastatin was given to enhance the chemotherapeutic efficacy of doxorubicin (DOX). Results We found a significant statistical reduction of ApoA1 in the tumor regions of specimens from gastric cancer and colorectal cancer patients. MKN45 cells proliferation was inhibited by 18% under the growing medium containing pravastatin. ApoA1 levels were elevated in liver Clone 9 cells administered pravastatin, but not in MKN45 cells. In vitro studies revealed that ApoA1 can reduce MKN45 tumor proliferation. Moreover, the tumor volume was significantly reduced in in vivo xenografts after the administration of pravastatin. Combined treatments of pravastatin with DOX significantly minimized the size of tumors, leading to a better therapeutic efficacy. Conclusion This study demonstrated that pravastatin elevated ApoA1, an HDL major constituent with anti-inflammatory characteristics, which displayed strong adversary associations with tumor developments and growth. Increasing the amounts of ApoA1 by pravastatin coupled with DOX may improve the therapeutic efficacy for cancer treatment.

Colorectal adenocarcinoma is a common cause death cancer in the whole world. The aim of this study is to define the 111In-cetuximab as a diagnosis tracer of human colorectal adenocarcinoma. In this research, cell uptake, nano-SPECT/CT scintigraphy, autoradiography, biodistribution and immunohitochemical staining of EGF receptor were included. HCT-116 and HT-29 cell expressed a relatively high and moderate level of EGF receptor, respectively. The nano-SPECT/CT image of 111In-cetuximab showed tumor radiation uptake of subcutaneous HCT-116 xenograft tumor was higher than SW-620. Autoradiography image also showed that tumor of HCT-116 had high 111In-cetuximab uptake. Mice that bearing CT-26 in situ xenograft colorectal tumors showed similar high uptake in vivo and ex vivo through nano-SPECT/CT imaging at 72 hours. Metastatic HCT-116/Luc tumors demonstrated the highest uptake at 72 hours after the injection of 111In-cetuximab. Relatively, results of 111In-DTPA showed that metabolism through urinary system, especially in the kidney. The quantitative analysis of biodistribution showed count value of metastatic HCT-116/Luc tumors that treated with 111In-cetuximab had a significant difference (P < 0.05) compared with that treated with 111In-DTPA after injection 72 hours. Result of immunohistologic staining of EGF receptor also showed high EGF receptor expression and uptake in metastatic colorectal tumors. In summary, we suggested that 111In-cetuximab will be a potential tool for detecting EGF receptor expression in human metastatic colorectal carcinoma.

The development of radioimmunotherapy has provided an impressive alternative approach in improving trastuzumab therapy. However, the mechanisms of trastuzumab and radiation treatment combined to increase therapeutic efficacy are poorly understood. Here, we try to examine the efficacy of cytotoxicity and apoptosis induction for (188)Re-HYNIC-trastuzumab in cancer cell lines with various levels of Her2.Fluorescence flow cytometry was used to detect the alterations of apoptosis induction after (188)Re-HYNIC-trastuzumab treatment in two breast cancer cell lines with different levels of HER2 (BT-474 and MCF-7) and a colorectal carcinoma cell line (HT-29) for control.Our results indicated that (188)Re-HYNIC-trastuzumab led to cell death of breast cancer cells specifically in HER2 level-dependent and radioactivity dose-dependent fashions. In BT-474 cells, 370 kBq/ml of (188)Re-HYNIC-trastuzumab enhanced the cytotoxicity to a level nearly 100-fold that of trastuzumab-alone treatment. The results also revealed that the mitochondria-dependent pathway attenuated irradiation-induced apoptosis in HER2-expressing breast cancer cells after (188)Re-HYNIC-trastuzumab treatment. In contrast, only after 48 h of (188)Re-HYNIC-trastuzumab treatment, BT-474 cells exhibited typical apoptotic changes, including exposure of phospholipid phosphatidylserine on the cell surface, or fragmented DNA formation, in a radioactivity dose-dependent manner.Briefly, our study demonstrates that (188)Re-labeled HYNIC-trastuzumab not only enhances cell death in a radioactivity dose-dependent fashion, but may also prolong the effects of apoptosis involved with the mitochondria-dependent pathway in HER2-overexpressing breast cancer cells. It is possible that the (188)Re-HYNIC-trastuzumab treatment induced a second round of apoptosis to prolong the effects of cell kill in these cancer cells. These data revealed that (188)Re-HYNIC-trastuzumab has the potential for use as a therapeutic radiopharmaceutical agent in HER2-overexpressing breast cancer cell treatment.

Ying-Hsia Shih,1,2 Xi-Zhang Lin,3 Chung-Hsin Yeh,1 Cheng-Liang Peng,1,2 Ming-Jium Shieh,2,4 Wuu-Jyh Lin,1 Tsai-Yueh Luo1,51Isotope Application Division, Institute of Nuclear Energy Research, Longtan, 2Institute of Biomedical Engineering, National Taiwan University, Taipei, 3Department of Internal Medicine, National Cheng Kung University, Tainan, 4Department of Oncology, National Taiwan University Hospital and College of Medicine, Taipei, 5Institute of Radiological Science, Central Taiwan University of Science and Technology, Taichung, TaiwanAbstract: Radiolabeled Lipiodol® (Guerbet, Villepinte, France) is routinely used in hepatoma therapy. The temperature-sensitive hydrogel polyethylene glycol-b-poly-DL-lactic acid-co-glycolic acid-b-polyethylene glycol triblock copolymer is used as an embolic agent and sustained drug release system. This study attempted to combine the polyethylene glycol-b-poly-DL-lactic acid-co-glycolic acid-b-polyethylene glycol hydrogel and radio-labeled Lipiodol to form a new radio-thermogelling emulsion, rhenium-188–N,N’-1,2-ethanediylbis-L-cysteine diethyl-ester dihydrochloride–Lipiodol/hydrogel (188Re-ELH). The therapeutic potential of 188Re-ELH was evaluated in a rodent hepatoma model. Rhenium-188 chelated with N,N’-1,2-ethanediylbis-L-cysteine diethyl-ester dihydrochloride was extracted with Lipiodol to obtain rhenium-188–N,N’-1,2-ethanediylbis-L-cysteine diethyl-ester dihydrochloride–Lipiodol (188Re-EL), which was blended with the hydrogel in equal volumes to develop 188Re-ELH. The 188Re-ELH phase stability was evaluated at different temperatures. Biodistribution patterns and micro-single-photon emission computed tomography/computed tomography images in Sprague Dawley rats implanted with the rat hepatoma cell line N1-S1 were observed after in situ tumoral injection of ~3.7 MBq 188Re-ELH. The therapeutic potential of 188Re-EL (48.58±3.86 MBq/0.1 mL, n=12) was evaluated in a 2-month survival study using the same animal model. The therapeutic effects of 188Re-ELH (25.52±4.64 MBq/0.1 mL, n=12) were evaluated and compared with those of 188Re-EL. The responses were assessed by changes in tumor size and survival rates. The 188Re-ELH emulsion was stable in the gel form at 25°C–35°C for >52 hours. Biodistribution data and micro-single-photon emission computed tomography/computed tomography images of the 188Re-ELH group indicated that most activity was selectively observed in hepatomas. Long-term 188Re-ELH studies have demonstrated protracted reductions in tumor volumes and positive effects on the survival rates (75%) of N1-S1 hepatoma-bearing rats. Conversely, the 2-month survival rate was 13% in the control sham group. Therapeutic responses differed significantly between the two groups (P

// Siao-Syun Guan 1,2 , Jungshan Chang 3 , Chun-Chia Cheng 2,3 , Tsai-Yueh Luo 2 , Ai-Sheng Ho 4 , Chia-Chi Wang 5 , Cheng-Tien Wu 1 and Shing-Hwa Liu 1,6,7 1 Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan 2 Institute of Nuclear Energy Research, Atomic Energy Council, Taoyuan, Taiwan 3 Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan 4 Division of Gastroenterology, Cheng Hsin General Hospital, Taipei, Taiwan 5 Division of Hepatology, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation and School of Medicine, Tzu Chi University, Hualien, Taiwan 6 Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan 7 Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan Correspondence: Shing-Hwa Liu, email: // Keywords : colorectal cancer / HER2 / afatinib / micelles Received : March 31, 2014 Accepted : May 30, 2014 Published : June 1, 2014 Abstract Colorectal cancer (CRC) is known as a common malignant neoplasm worldwide. The role of EGFR/HER2 in CRC is unclear. Afatinib is an irreversible EGFR/HER2 inhibitor. There were few studies of afatinib on CRC. Here, we investigated the protein levels/expressions of HER2 in sera and tumors from CRC patients and the therapeutic effect of afatinib on HER2-overexpressed CRC in vitro and in vivo . The increased HER2 levels were detected in the collected sera and tumors of patients with CRC. The serological HER2 levels were correlated with the tumor HER2 expressions in patients. Afatinib also inhibited the HER2-positive tumor cell growth and caused apoptosis in HER2-overexpressed human colorectal cancer HCT-15 cells but not in low HER2 expressed human gastric cancer MKN45 cells. In vivo study showed that afatinib reduced tumor growth in HER2-overexpressed xenografts. Moreover, afatinib-encapsulated micelles displayed higher cytotoxic activity in HCT-15 cells and were more effective for tumor growth suppression in HCT-15-induced tumor xenografts than afatinib performance alone. Taken together, these findings suggest that higher serum HER2 levels reflect the higher HER2 contents in tumors of CRC patients, and the improved afatinib-encapsulated micelles possess high therapeutic efficacy in HER2-overexpressed CRC in vitro and in vivo .

Introduction In patients with unresectable HCC, transcatheter arterial chemoembolization (TACE) is a widely used treatment. Recently, as an alternative treatment modality for HCC, transcatheter arterial embolization with radioisotopes has been investigated. In this study, we compared the therapeutic efficacy of an intra-hepatic arterial injection of Re-188-MN-16ET-lipiodol and the TACE method in rats with liver tumors. Methods Twelve male rats bearing hepatic tumors were divided into three groups to evaluate the efficacy of treatment (four in each group). Group 1 received an intra-hepatic arterial injection of 0.2 mCi of Re-188-MN-16ET-lipiodol; group 2 received epirubicin (0.5 mg/kg) and 0.1 ml of lipiodol emulsion; group 3 received 0.1 ml of normal saline and served as the control group. Tumor size was measured by liver sonography before injection, at two weeks, four weeks and eight weeks after injection. Survival time was calculated from the day of treatment to 56 days after treatment by the life-table method. The response to treatment and the survival time in each group were evaluated and compared. Results All rats treated with Re-188 MN-16ET-lipiodol showed good response to the therapy. Their tumor size decreased and all rats survived over eight weeks. All rats treated with epirubicin plus lipiodol survived over 8 weeks; however, two rats (50%) showed increased tumor size in the 8th week. As for the control group (rats treated with normal saline), all rats survived less than 37 days with continuous tumor growth. Conclusion Results showed that Re-188-MN-16ET-lipiodol can be a potential therapeutic pharmaceutical for the treatment of liver tumors.

Intratumoral injection of a radiopharmaceutical is a potential modality to treat liver tumors. Rhenium-188 ((188)Re) was used to chelate with ethyl cysteinate dimer (ECD) in lipiodol solution to form (188)Re-ECD/lipiodol, which was then evaluated for its therapeutic potential in a rodent hepatoma model.Male Sprague-Dawley rats were implanted with N1-S1 hepatoma cells orthotopically and randomly divided into two groups. Group 1 (n = 29) and group 2 (n = 10) received (188)Re-ECD/lipiodol (30.4 +/- 21.8 MBq/0.1 mL) and 0.1 mL of normal saline by intratumoral injection, respectively. Three rats in group 1 were imaged by micro-single-photon emission computed tomography/computed tomography scan to evaluate the biodistribution pattern. All rats were monitored for change of tumor size and survival rate after 2 months.The in vitro stability test showed that (188)Re-ECD was well-retained in the lipiodol phase for 48 hours. The biodistribution image revealed that radioactivity was retained well in hepatomas 24 hours postinjection. Long-term studies demonstrated that rats treated with (188)Re-ECD/Lipiodol had smaller tumor volumes and a better survival rate, compared to the control group. At the end of observation, the survival rates in groups 1 and 2 were 62% and 20%, respectively (p0.05).(188)Re-ECD/lipiodol via direct intratumoral injection shows potential for treating hepatoma and warrants further clinical trials.

Nanoliposomes are important carriers capable of packaging drugs for various delivery applications through passive targeting tumor sites by enhanced permeability and retention effect. Radiolabeled liposomes have potential applications in radiotherapy and diagnostic imaging. The purpose of this study was to investigate the biodistribution, pharmacokinetics and imaging of nanotargeted (188)Re-N,N-bis (2-mercaptoethyl)-N',N'-diethylethylenediamine (BMEDA)-labeled pegylated liposomes (RBLPL) and unencapsulated (188)Re-BMEDA after intraperitoneal (ip) injection in a C26 colon carcinoma ascites mouse model. The nanopegylated liposomes were labeled with (188)Re-BMEDA. The labeling efficiency of RBLPL was 82.3+/-4.5%. In vitro stability of RBLPL in normal saline at room temperature and in rat plasma at 37 degrees C for 72 h was 92.01+/-1.31% and 82.4+/-1.64%, respectively. The biodistribution studies indicated that the radioactivity in ascites was 69.96+/-14.08 percentage injected dose per gram (% ID/g) at 1h to 5.99+/-1.97% ID/g at 48 h after ip administration of RBLPL. The levels of radioactivity in tumor were progressive accumulation to a maximum of 6.57+/-1.7% ID/g at 24 h. The radioactivity of (188)Re-BMEDA in ascites reached the maximum level of 54.89+/-5.91% ID/g at 1 h and declined rapidly with time. Pharmacokinetic studies revealed that the terminal half-life, total body clearance and area under the curve of RBLPL were 5.3-, 9.5- and 9.4-fold higher than that of (188)Re-BMEDA in blood, respectively. These results suggested that the long circulation, bioavailability and localization of RBLPL in tumor and ascites sites, which also demonstrate that the ip administration of RBLPL is a potential multifunctional nanoradiotherapeutics and imaging agents on a C26 colon carcinoma ascites mouse model.

In order to assess the effect of hypercholesterolemia on cardiac sympathetic nerve function, New Zealand white rabbits were fed a normal diet (the control group) or one enriched with 0.5% cholesterol [the hypercholesterol (HC) group] for 3 months. Before and after the 3-month diet treatment, we performed serial imaging examinations and analyzed the uptake and washout ratio of (123)I-meta-iodobenzylguanidine ((123)I-MIBG) from the myocardium by administration of (123)I-MIBG through an ear vein. At the end of the experiments, the rabbits were sacrificed, and right ventricular strips were taken from their hearts. The inotropic response of the right ventricular strips to isoproterenol (ISO) and norepinephrine (NE) were evaluated. The cardiac MIBG uptake of the HC group, which was evaluated using the heart to mediastinum ratio, was higher than that of the age-matched control group. However, the washout ratios of (123)I-MIBG did not differ statistically between the two groups. On pretreatment with cocaine, NE-enhanced contractility was greater in papillary muscles isolated from the HC group. The concentration-response curve to ISO was shifted to the right in the HC group, compared with that in the control group. In conclusion, hypercholesterolemia in rabbits resulted in an increase in sympathetic nerve density in the myocardium, a decrease in the inotropic response to ISO and an increase in the inotropic response to NE in cocaine-treated myocardium. Both the in vivo and in vitro studies demonstrated the functional significance of neural remodeling induced by hypercholesterolemia.

In our recent study, we developed a new radiopharmaceutical (Re-188 MN-16ET lipiodol) with encouraging results for the treatment of liver malignancy. In this study, we further evaluated the therapeutic efficacy of this radiopharmaceutical by measuring tumor response and survival times in rats with liver tumors after intra-hepatic arterial injection of Re-188 MN-16ET lipiodol.Twelve male rats bearing hepatic tumors were divided into three groups. Group 1 received an intra-hepatic arterial injection of 18.5 MBq Re-188 MN-16ET lipiodol; Group 2 received lipiodol and Group 3 received normal saline. Tumor size was measured by liver sonography before injection, at 2, 4, and 8 weeks after injection. Survival time and response rate were calculated.All rats showed good response and survived over 60 days in Group 1 while all rats showed poor response in Group 2 and Group 3 with only 25 % of rats in Group 2 and none (0 %) in Group 3 survived over 60 days. The p value was 0.0067 between Group 1 and Group 3; 0.04 between Group 1 and Group 2; and 0.034 between Group 2 and Group 3.Re-188 MN-16ET lipiodol has good potential for the treatment of hepatoma.

Herceptin is widely used in treating Her2-overexpressing breast cancer. However, the application of Herceptin in prostate cancer is still controversial. Our previous results have indicated the relevance of Her2 in the transition of the androgen requirement in prostate cancer cells. In this study, the effects of radioimmunotherapy against Her2 in prostate cancer were investigated.DU145, an androgen receptor-negative prostate cancer cell line, was used in vitro and in vivo to evaluate the effects of Herceptin labeled with a beta emitter, Rhenium-188 (Re-188). Its effects on cell growth, extent of apoptosis, the bio-distribution of Re-188 labeled Herceptin (Re-H), and protein levels were determined.Treatments with Re-188 and Re-H reduced the proliferation of DU145 cells in dose- and time-dependent manners compared to the Herceptin-treated group. Growth inhibition and apoptosis were induced after Re-H treatment; growth inhibition was more distinct in cells with high Her2/p-Her2 levels. Our in vivo xenograft studies revealed that Re-H treatment significantly retarded tumor growth and altered the levels of apoptosis-related proteins. The bio-distribution of Re-H in mice demonstrated a tissue-specific pattern. Importantly, the levels of p35 protein, which is related to cancer cell survival and invasion, dramatically decreased after Re-H treatment.Our data demonstrate that Re-188-labeled Herceptin effectively inhibited the growth of DU145 cells compared to the Herceptin- and Re-188-treated cohorts. This implies that targeting Her2 by both radio- and immuno- therapy might be a potential strategy for treating patients with androgen-independent prostate cancer.

Neuroblastic tumors are childhood neoplasms that possess amino acid decarboxylase (AADC) activity and can theoretically be imaged by (18)F-fluorodihydroxyphenylalanine ((18)F-FDOPA) PET, a new diagnostic tool for neuroendocrine tumors. In this study, we explored the accuracy and clinical role of (18)F-FDOPA PET in neuroblastic tumors.From 2008 to 2011, patients with tissue-proven neuroblastic tumors receiving (18)F-FDOPA PET at initial diagnosis or during follow-ups were enrolled. The sensitivity and specificity of (18)F-FDOPA PET were compared with those of (123)I-metaiodobenzylguanidine ((123)I-MIBG) scintigraphy and (18)F-FDG PET, using tumor histology as the standard. The maximum standardized uptake value and tumor-to-liver uptake ratio on (18)F-FDOPA PET were measured and correlated with AADC messenger RNA level in tumor tissue.Fifty tumors from 34 patients, including 42 neuroblastic tumors and 8 lesions without viable tumor cells, were eligible for analysis. (18)F-FDOPA PET successfully detected neuroblastic tumors of different histologic types in various anatomic sites, at a sensitivity of 97.6% (87.4%-99.9%) and a specificity of 87.5% (47.3%-99.7%). In tumors with concomitant studies, (18)F-FDOPA PET demonstrated a higher sensitivity than (123)I-MIBG scintigraphy (n = 18; P = 0.0455) or (18)F-FDG PET (n = 46; P = 0.0455). Among the 18 tumors with concomitant (123)I-MIBG scans, 4 tumors with viable cells were (123)I-MIBG-negative but were successfully detected by (18)F-FDOPA PET. The tumor uptake of (18)F-FDOPA significantly correlated with AADC expression (n = 15 nonhepatic tumors; maximum standardized uptake value, P = 0.0002; tumor-to-liver uptake ratio, P0.0001).(18)F-FDOPA PET showed high sensitivity and specificity in detecting and tracking neuroblastic tumors in this preliminary study with a small cohort of patients and might be complementary to (123)I-MIBG scintigraphy and (18)F-FDG PET. By correlating with AADC expression, (18)F-FDOPA PET might serve as a useful imaging tool for the functional assessment of neuroblastic tumors.

Introduction Hepatocellular carcinoma is the most common form of primary hepatic carcinoma. A new N 2 S 2 tetradentate ligand, N -[2-(triphenylmethyl)thioethyl]-3-aza-19-ethyloxycarbonyl-3-[2-(triphenylmethyl)thioethyl]octadecanoate (H 3 MN-16ET), was introduced and labeled with 188 Re to create 188 Re-MN-16ET in the Lipiodol phase. The potential of 188 Re-MN-16ET/Lipiodol for hepatoma therapy was evaluated in a hepatocellular carcinoma animal model of Sprague–Dawley rats implanted with the N1S1 cell line. Methods Synthesis of H 3 MN-16ET was described, and characterization was identified by infrared, nuclear magnetic resonance and mass spectra. We compared the effects of transchelating agents (glucoheptonate or tartaric acid) and a reducing agent (stannous chloride) on the complexing of 188 Re-perrhenate and H 3 MN-16ET. Twenty-four rats implanted with hepatoma were injected with 3.7 MBq/0.1 ml of 188 Re-MN-16ET/Lipiodol or 188 Re-MN-16ET via transcatheter arterial embolization. Biodistribution experiments and single-photon emission computed tomography imaging were performed to investigate tumor accumulation. Results H 3 MN-16ET was proved to easily conjugate with the Re isotope and showed good solubility in Lipiodol. The radiochemical purity of 188 Re-MN-16ET/Lipiodol with 10 mg tartaric acid and stannous chloride was shown to be more than 90%. The major distribution sites of 188 Re-MN-16ET in Sprague–Dawley rats were hepatoma and the liver. However, the radioactivity at the tumor site postadministered with 188 Re-MN-16ET was quickly decreased from 9.15±0.23 (at 1 h) to 2.71%±0.18% of injected dose/g (at 48 h). The biodistribution and micro-single-photon emission computed tomography/computed tomography image data showed that 188 Re-MN-16ET/Lipiodol was selectively retained at the tumor site, with 11.55±1.44, 13.16±1.46 and 10.67%±0.95% of injected dose/g at 1, 24 and 48 h postinjection, respectively. The radioactivity in normal liver tissue was high but significantly lower than that of the tumors. Conclusion H 3 MN-16ET is a suitable tetradentate ligand for 188 Re labeling. From the animal data, we suggest that 188 Re-MN-16ET/Lipiodol has the potential to be a therapeutic radiopharmaceutical for hepatoma treatment.

Introduction Radioimmunotherapy, which utilizes monoclonal antibodies and therapeutic radioisotopes against antigen-expressing tumor tissues, is an attractive therapeutic approach for cancer therapy. Trastuzumab (Herceptin) is a humanized anti-HER-2/neu monoclonal antibody for breast cancer treatment. In this paper, we introduce a new radioimmunoagent, 188 Re-trastuzumab, via a bifunctional ligand, succinimidyl 3,6-diaza-5-oxo-3-[2-((triphenylmethyl)thio)ethyl]-8-[(triphenylmethyl)thio]octanoate (SOCTA), and evaluate its potential to be a therapeutic radiopharmaceutical for breast cancer treatment. Methods Equimolar amounts of SOCTA and trastuzumab were selected to react, and the conjugation ratio of SOCTA–trastuzumab was evaluated by the MALDI-TOF method. The immunoreactivity of SOCTA–trastuzumab was compared with nonconjugated trastuzumab in HER-2/neu overexpressing human breast cancer cell BT-474. Biodistribution experiment and microSPECT/CT images of 188 Re-SOCTA–trastuzumab being administered intravenously to SCID mice bearing xenografted BT-474 breast cancer were investigated to evaluate the tumor-targeting capability. Results The covalent attachment of SOCTA to trastuzumab (at 1:1 molar ratio) resulted in the averaged conjugation ratio of 0.27±0.06 ( n =3). The complex could easily be labeled with 188 Re and achieve 95% radiochemical purity (RCP) after 1 h of reaction at room temperature. The in vitro stability study also revealed that the RCP of 188 Re-SOCTA–trastuzumab was at a value of more than 85% after 48 h of incubation with human serum. The immunoreactivity evaluation showed that SOCTA–trastuzumab and nonconjugated trastuzumab had similar binding capacity ( B max ) to HER-2/neu receptor in BT-474 cells. The animal experiments showed that 188 Re-SOCTA–trastuzumab accumulated more intensively in the tumor site as compared to normal tissue. Conclusion We suggest that 188 Re-SOCTA–trastuzumab could be a potential candidate for radioimmunotherapy.

Purpose: Several studies have reported significant renal toxicity after the use of a high dose of90Y-DOTATOC. Thus, renal protection is necessary in treatments with90Y-DOTA Tyr3-octroetide (DOTATOC). The infusion of certain positively charged amino acids has been shown to effectively reduce renal uptake of DOTATOC. In this study, we compared the effectiveness of three kinds of amino acids, D-lysine (lysine),L-arginine (arginine) and histidine, on renal protection in healthy rats and tried to determine which one was the most effective.Methods: Twenty SD healthy male rats were divided into 4 groups: lysine, histidine, arginine, and control. The rats were injected with a dose of 400 mg/kg of amono acid or 2 ml of phosphate-buffered saline (PBS) (as control) intraperitoneally. All rats were sacrificed at 4 hrs after the injection of 1 MBq111In-DOTATOC. Samples of the kidney were taken and weighed carefully. The counts of radioactivity were measured by a gamma counter and renal concentrations were calculated and expressed as percent injected dose per gram (% ID/g).Results: The renal uptake of111In-DOTATOC was significantly lower for all three kinds of amino acids when compared to the control group. The renal uptake of111In-DOTATOC in the lysine group was significantly lower than those in the histidine and arginine groups. The renal uptake of111In-DOTATOC in the histidine group was lower than that in the arginine group, but no statistical difference was noted.Conclusion: Among these three amino acids, lysine had the best reduction rate of renal uptake of DOTATOC. Histidine was more effective than arginine but no statistical difference was noted.

111In-DTPA octreotide (DTPAOC) has been used for detecting somatostatin receptor positive tumor for years. In-111 DOTA-Tyr3-octreotide (DOTATOC) is newly developed for diagnostic and therapeutic purposes. In this study, we compared the biodistribution and tumor uptake ratio after injection of In-111 DTPAOC and In-111 DOTATOC in rats. Twelve rats bearing pancreatic tumors were divided into two groups: six rats were sacrificed at 4 hr after injection of 3.7 MBq of In-111 DTPAOC and another 6 rats were sacrificed at the same time after injection of 3.7 MBq of In-111 DOTATOC. Samples of various organs were obtained and counted to calculate the tissue concentration. In addition, 12 rats bearing pancreatic tumors were scanned at 4, 24, and 48 hr after injection of 37 MBq of In-111 DTPAOC or In-111 DOTATOC. The tumor uptake ratios (T/N ratio) were calculated. The biodistribution data showed that the activity in the tumor as well as in the kidney was significantly higher in the In-111 DOTATOC group than in the In-111 DTPAOC group, although both radiopharmaceuticals had the expected high affinity to the tumor. The T/N ratios in the In-111 DOTATOC group were also significantly higher than those in the In-111 DTPAOC group at 24 hr after injection. We conclude that In-111 DOTATOC showed lower clearance than In-111 DTPAOC in the rats bearing pancreatic tumors, although both of these radiopharmaceuticals showed expected high tumor uptake.

Radiolabeled Lipiodol has routinely been used in hepatoma therapy. In this article an attempt to develop a new 188 Re-ECD/Lipiodol radiopharmaceutical, in which the chelating agent ECD (ethyl cyteinate dimer), is the constituent of the known brain perfusion agent 99m Tc-ECD, and an evaluation of its stability and biodistribution in rats with hepatic tumors is presented. First, 188 Re-ECD was prepared in a vial, followed by extraction with Lipiodol to get the final product, 188 Re-ECD/Lipiodol. The optimal labeling conditions for 188 Re-ECD were: (1) tartaric acid which is better than EDTA as a weak chelating agent; and (2) 15 mg of SnCl 2 , as the reducing agent, and 5–10 mg of tartaric acid in each vial had a better labeling yield. The radiochemical purity of 188 Re-ECD/Lipiodol was more than 94%. Twenty-four male Sprague-Dawley rats with liver tumors were sacrificed at 1, 24, and 48 h (eight rats each time) after an injection of approximately 7.4 MBq of 188 Re-ECD/Lipiodol via the hepatic artery. The radioactivity in the liver tumor is significantly high following therapeutic arterial injection, and relatively low in other organs including the bone, spleen, brain, thyroid, stomach, muscle, blood, and testis throughout this study. In conclusion, the new preparation of 188 Re-ECD/Lipiodol is a candidate agent for the treatment of liver cancer.