Albumin-binding agents enhance tumor uptake of radiopharmaceuticals targeting prostate-specific membrane antigens (PSMAs) in radiotherapy. We synthesized PSMA-NARI-56, a molecule with both PSMA targeting activity and albumin-binding moiety, labeled with 177Lu as the therapeutic agent. The aim of this study was to determine the specific binding of 177Lu-PSMA-NARI-56 towards PSMA, assess its biodistribution, and evaluate therapeutic effectiveness by tumor-bearing mice. The effect of 177Lu-PSMA-NARI-56 viability of PSMA-positive cell (LNCaP) was evaluated. Biodistribution and endoradiotherapy studies were utilized to determine the distribution, targeting, and anti-tumor efficacy by tumor-bearing mice identified by 111In-PSMA-NARI-56. 177Lu-PSMA-NARI-56 exhibited a significant impact on the viability of the LNCaP cell. Biodistribution results revealed the maximum tumor uptake of 177Lu-PSMA-NARI-56 occurring within 24 h, reaching 40.56 ± 10.01%ID/g. In radionuclide therapy, at 58 days post-injection (p.i.), 177Lu-PSMA-NARI-56 demonstrated superior tumor inhibition (98%) compared to 177Lu-PSMA-617 (58%), and the mouse survival rate after 90 days of radiotherapy (90%) was also higher than that of 177Lu-PSMA-617 (30%) in LNCaP tumor-bearing mice. In the PSMA-positive animal model, 177Lu-PSMA-NARI-56 shows higher potential radiotheranostic and prolonged accumulation (identify by 111In-PSMA-NARI-56/nanoSPECT/CT image), offering the potential for improved treatment effectiveness and increased survival rates when compared to 177Lu-PSMA-617.

The prostate-specific membrane antigen (PSMA) is a great target for prostate cancer in the current. The MH-PC-AB-56, a molecule with PSMA-targeted activity and with an albumin-binding motif, was radiolabeled with indium as a diagnostic agent and with lutetium with a therapeutic agent, respectively. We evaluated the molecule's theranostic application with 111In and 177Lu in NanoSPECT/CT imaging. Methods: The radiolabeled peptide, 111In/177Lu-MH-PC-AB-56, was performed with sodium acetate buffer and heating with 15 min or 30 min at 95℃. The radiochemical purity was analyzed by TLC and HPLC. The PSMA-expressed tumor cell LNCaP was implanted right front leg at BALB/c nude mice. NanoSPECT/CT image was performed at 1 h, 4 h, 24 h, 48 h, 72 h, and 96 h after injection of 111In-MH-PC-AB-56 or 177Lu-MH-PC-AB-56. Results: The radiochemical purity of 111In-MH-PC-AB-56 or 177Lu-MH-PC-AB-56 was 99.09 ± 0.38

The Arg–Gly–Asp (RGD) peptide shows a high affinity for αvβ3 integrin, which is overexpressed in new tumor blood vessels and many types of tumor cells. The radiolabeled RGD peptide has been studied for cancer imaging and radionuclide therapy. We have developed a long-term tumor-targeting peptide DOTA-EB-cRGDfK, which combines a DOTA chelator, a truncated Evans blue dye (EB), a modified linker, and cRGDfK peptide. The aim of this study was to evaluate the potential of indium-111(111In) radiolabeled DOTA-EB-cRGDfK in αvβ3 integrin-expressing tumors. The human glioblastoma cell line U-87 MG was used to determine the in vitro binding affinity of the radiolabeled peptide. The in vivo distribution of radiolabeled peptides in U-87 MG xenografts was investigated by biodistribution, nanoSPECT/CT, pharmacokinetic and excretion studies. The in vitro competition assay showed that 111In-DOTA-EB-cRGDfK had a significant binding affinity to U-87 MG cancer cells (IC50 = 71.7 nM). NanoSPECT/CT imaging showed 111In-DOTA-EB-cRGDfK has higher tumor uptake than control peptides (111In-DOTA-cRGDfK and 111In-DOTA-EB), and there is still a clear signal until 72 h after injection. The biodistribution results showed significant tumor accumulation (27.1 ± 2.7% ID/g) and the tumor to non-tumor ratio was 22.85 at 24 h after injection. In addition, the pharmacokinetics results indicated that the 111In-DOTA-EB-cRGDfK peptide has a long-term half-life (T1/2λz = 77.3 h) and that the calculated absorbed dose was safe for humans. We demonstrated that radiolabeled DOTA-EB-cRGDfK may be a promising agent for glioblastoma tumor imaging and has the potential as a theranostic radiopharmaceutical.

Pancreatic cancer is usually asymptomatic in the early stages; the 5-y survival rate is around 9%; and there is a lack of effective treatment. Here we show that SSEA-4 is more expressed in all pancreatic cancer cell lines examined but not detectable in normal pancreatic cells; and high expression of SSEA-4 or the key enzymes B3GALT5 + ST3GAL2 associated with SSEA-4 biosynthesis significantly lowers the overall survival rate. To evaluate potential new treatments for pancreatic cancer, homogeneous antibodies with a well-defined Fc glycan for optimal effector functions and CAR-T cells with scFv construct designed to target SSEA-4 were shown highly effective against pancreatic cancer in vitro and in vivo. This was further supported by the finding that a subpopulation of natural killer ( NK) cells isolated by the homogeneous antibody exhibited enhancement in cancer- cell killing activity compared to the unseparated NK cells. These results indicate that targeting SSEA-4 by homologous antibodies or CAR-T strategies can effectively inhibit cancer growth, suggesting SSEA-4 as a potential immunotherapy target for treating pancreatic disease.

3114 Objectives: MH-PC-AB-53 showed high binding affinity for prostate-specific membrane antigen. Radiolabeled PSMA peptides that are prostate specific can be used for prostate -targeted radiotheragnostic application. The MH-PC-AB-53 (15-30μg) was labeled with ~3 or ~6mCi InCl3 (from INER) in sodium acetate (NaOAc) with different pH values (4.0-6.0) at 95℃ within 15mins. After labeling with In-111, quality control was performed by RP-HPLC and radio thin layer chromatography. Radiochemical purity was analyzed in the radio-TLC scanner with a 0.1M citric acid solution as the mobile phase. The Rf of free In-111 was approximately 0.95, and the Rf of 111In -MH-PC-AB-53 was approximately 0.05. The Radiochemical purity of the 111In-MH-PC-AB-53 was assayed by TLC(96.8%) and HPLC (96%). LNCaP tumor bearing mice were intravenously injected with 111In -MH-PC-AB-53. Scans were performed 1, 4, and 24 h after the administration. 111In-MH-PC-AB-53 showed high tumor uptake at all time points.

The objective of this study was to evaluate radiolabeled DOTA-SP90 as a radiotracer for breast cancer. The in vitro competition assay showed that radiolabeled DOTA-SP90 had significant binding affinity to BT-483 cancer cells. Biodistribution, nanoSPECT/CT and nanoPET/CT imaging results indicated that radiolabeled DOTA-SP90 can accumulate in tumors. In addition, radiolabeled DOTA-SP90 peptides can also detect metastatic tumors. Therefore, radiolabeled SP90 peptide may provide the potential capability as diagnostic agent for breast cancer patients.

3097 Introduction: Prostate-specific membrane antigen (PSMA) is a well-known targeting for prostate cancer. PSMA-617 is prostate radionuclide ligand therapy (PRLT) classic idol of NAAG inhibitor-modified. We design a precursor MH-PC-AB-9 that has a spacer link urea-based NAAG inhibitor and albumin binder to change the pharmacokinetics of NAAG inhibitor for PSMA. We use lysine, tyrosine, tyrosine, and glutamic acid (from N-terminal to C-terminal) as a spacer. And 4-(p-Tolyl) butyric acid link the lysine9s side chain as an albumin binder. The chelator is DOTA and the one carboxylic acid of DOTA is conjugating with lysine’ N-terminal. Methods: 20 μg of the precursor was diluted with sodium acetate buffer pH6.0 and added to 0.1 GBq of [In-111] InCl3 in 0.01N HCl. The solution heated to 95 ℃ for 15 min with 500 rpm agitation. Radiochemical purity was established by thin layer chromatography (TLC) and high pressure liquid chromatography (HPLC). The TLC chamber was loaded with 10 % methanol in water. The Xselect HSS T3 column (4.6 mm x 250 mm) was used and eluted with a linear gradient from 20 to 60% acetonitrile in water (0.1% TFA) over 10 min at a flow rate of 0.8 mL/min. The detector was used gamma radiated detector and UV detector was adjusted for 220 nm. The bioactivity to recognized PSMA of [In-111] In-MH-PC-AB-9 was performed by LNCaP tumor-bearing mice. Results: The chemical purity of [In-111] In-MH-PC-AB-9 was over 95% determined by TLC and HPLC. The retardation factor of free [In-111] In is 0.27 and [In-111] In-MH-PC-AB-9 is 0.95 in TLC. The retention time of free [In-111] In is 3.26 min and [In-111] In-MH-PC-AB-9 is 11.052 min in HPLC. The distribution of [In-111] In-MH-PC-AB-9 in tumor-bearing mice was imaging with nano-SPECT/CT at 1, 24, 72 hours. There still has radioactive accumulated until post-injection 72 hours at the tumor site. Conclusions: The precursor MH-PC-AB-9 has long circulating time was provided by labeling with [In-111] InCl3 and injected into tumor-bearing mice. And the radioactive was increasing with post-injected time. Hence, MH-PC-AB-9 has improved the blood half-life of the NAAG inhibitor more than PSMA-617. Supporting data Figure1. Thin layer chromatography to analyze the radiochemical purity of [In-111] In-MH-PC-AB-9. A is free [In-111] InCl3; B is [In-111] In-MH-PC-AB-9. Figure2. The radiochemical purity of [In-111] In-MH-PC-AB-9 is analyzed by HPLC. The A and B is radio detector; C is UV detector. Figure3. The biodistribution of [In-111] In-MH-PC-AB-9 is imaging with nano-SPECT/CT at post-injected 1, 24 and 72 hours.

2019 Objectives: Peptide Receptor Radionuclide Therapy (PRRT) is a widely known molecular targeted therapy. PRRT is performed by using a small peptide which is combined with therapeutic radionuclides. We tried to develop a multimodality compound for both PRRT and Boron Neutron capture therapy (BNCT), and also both the binding affinity and the ratio of tumor to normal tissue (T/N) of boron drug will be high than traditional BNCT drugs. We selected peptide-NPY derivative, modified with BSH analogue, as a multimodality drug for BNCT. Neuropeptide Y (NPY) is a 36-amino acid peptide and regulates in various physiological functions through its four receptors. Its receptors are a family of G protein-coupled receptors and can be divided into five subtypes.The aims of this study was to synthesize a long-circulated NPY derivative and evaluate tumor image of the MCF-7 and 4T1 animal model as a candidate for breast cancer therapy. Methods: We synthesized DOTA-Boron-ENPY, which is a 16-amino acid NPY derivative. In our research strategy, we used the recombination of EB(Albumin affinity compound), DOTA, BSH and breast cancer targeted NPY-peptide as the pharmacophore for BNCT, once label with In-111 for PRRT. 30-60μg DOTA-Boron-ENPY peptide reacted with 6mCi indium-111 chloride (from INER) at 95℃ within 15min. The radiochemical purity was detected by Radio-HPLC. In animal study, tumor xenografts were performed in 6-wk-old female BALB/c mice by subcutaneous injection of2[asterisk]106 4T1 cells, and nanoSPECT/CT imaging was performed at 0.5 h to 96h after injecting of the 111In-DOTA-Boron-ENPY.Results: The radiochemical purity of 111In-DOTA-Boron-ENPY was greater than 90%. In vivo study, MCF-7 animal tumors uptake was greater than 7% ID/g in 72 hours post-injection for111In-DOTA-Boron-ENPY. In the 4T1 animal model, tumors uptake was greater than 30% ID/g in 48 hours post-injection for111In-DOTA-Boron-ENPY. It also has a high tumor to muscle ratio (T/M) greater than 4. Conclusions: From the in vivo study, we consider the DOTA-Boron-ENPY as a long circulation radiopharmaceutical candidate for companion diagnostics (CDx). It can be a potential candidate drug in breast tumor for BNCT.

Neuropeptide Y (NPY) is a 36-amino acid peptide and regulates in various physiological functions through its four receptors.Recently, NPY receptor-Y1R has been found to be overexpressed in breast carcinomas.Although the truncated NPY analog has high affinity with Y1R, it is rapidly metabolized, resulting in low tumor uptake.The aims of this study were to synthesize a long-circulated NPY analog and evaluate tumor image of the 4T1 animal model as a candidate for breast cancer therapy.

Introduction: Epidepride is a compound with an affinity in picomolar range for D-2/D-3 receptors. The aim of this work was designed to investigate the diagnostic possibility of [I-123]epidepride imaging platform for risperidone-treatment chronic MK-801-induced rat schizophrenia model.Methods: Rats received repeated administration of MK-801 (dissolved in saline, i.p., 0.3 mg/kg/day) or saline for 4 weeks. After 1-week administration of MK-801, rats in MK-801 + risperidone group received risperidone (0.5 mg/kg/day) intraperitoneally 15 min prior to MK-801 administration for the rest of 3-week treatment. We obtained serial [I-123]epidepride neuroimages from nanoSPECT/CT and evaluated the alteration of specific binding in striatum and midbrain.Results: Risperidone reversed chronic MK-801-induced decrease in social interaction duration.IHC and ELISA analysis showed consistent results that chronic MK-801 treatment significantly decreased striatal and midbrain D2R expression but repeated risperidone administration reversed the effect of MK-801 treatment. In addition, [I-123]epidepride nanoSPECT/CT neuroimaging revealed that low specific [I-123]epidepride binding ratios caused by MK-801 in striatum and midbrain were statistically alleviated after 1- and 2-week risperidone administration, respectively.Conclusions: We established a rat schizophrenia model by chronic MK-801 administration for 4 weeks. [I-123] Epidepride nanoSPECT neuroimaging can trace the progressive alteration of D2R expression in striatum and midbrain caused by long-lasting MK-801 treatment. Besides diagnosing illness stage of disease, [I-123] epidepride can be a useful tool to evaluate therapeutic effects of antipsychotic drug in chronic MK-801-induced rat schizophrenia model. (C) 2014 Elsevier Inc. All rights reserved.

Radiolabeled annexin V (ANV) has been widely used for imaging cell apoptosis. Recently, a novel ANV-Kunitz-type protease inhibitor fusion protein, ANV-6L15, was found to be a promising probe for improved apoptosis detection based on its higher affinity to phosphatidylserine (PS) compared to native ANV. The present paper investigates the feasibility of apoptosis detection using radioiodinated ANV-6L15. Native ANV and ANV-6L15 were labeled with iodine-123 and iodine-125 using Iodogen method. The binding between the radioiodinated proteins and erythrocyte ghosts or chemical-induced apoptotic cells was examined. ANV-6L15 can be radioiodinated with high yield (40%−60%) and excellent radiochemical purity (>95%). 123I-ANV-6L15 exhibited a higher binding ratio to erythrocyte ghosts and apoptotic cells compared to 123I-ANV. The biodistribution of 123I-ANV-6L15 in mice was also characterized. 123I-ANV-6L15 was rapidly cleared from the blood. High uptake in the liver and the kidneys may limit the evaluation of apoptosis in abdominal regions. Our data suggest that radiolabled ANV-6L15 may be a better scintigraphic tracer than native ANV for apoptosis detection.