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Sample records for 64cu-labeled dota-d-phe1-tyr3-octreotide 64cu-dota-toc

  1. Evaluation of (64)Cu-labeled DOTA-D-Phe(1)-Tyr (3)-octreotide ((64)Cu-DOTA-TOC) for imaging somatostatin receptor-expressing tumors.

    PubMed

    Hanaoka, Hirofumi; Tominaga, Hideyuki; Yamada, Keiich; Paudyal, Pramila; Iida, Yasuhiko; Watanabe, Shigeki; Paudyal, Bishnuhari; Higuchi, Tetsuya; Oriuchi, Noboru; Endo, Keigo

    2009-08-01

    In-111 ((111)In)-labeled octreotide has been clinically used for imaging somatostatin receptor-positive tumors, and radiolabeled octreotide analogs for positron emission tomography (PET) have been developed. Cu-64 ((64)Cu; half-life, 12.7 h) is an attractive radionuclide for PET imaging and is produced with high specific activity using a small biomedical cyclotron. The aim of this study is to produce and fundamentally examine a (64)Cu-labeled octreotide analog, (64)Cu-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-D: -Phe(1)-Tyr(3)-octreotide ((64)Cu-DOTA-TOC). (64)Cu produced using a biomedical cyclotron was reacted with DOTA-TOC for 30 min at 45 degrees C. The stability of (64)Cu-DOTA-TOC was evaluated in vitro (incubated with serum) and in vivo (blood collected after administration) by HPLC analysis. Biodistribution studies were performed in normal mice by administration of mixed solution of (64)Cu-DOTA-TOC and (111)In-DOTA-TOC and somatostatin receptor-positive U87MG tumor-bearing mice by administration of (64)Cu-DOTA-TOC or (64)Cu-1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetraacetic acid-octreotide ((64)Cu-TETA-OC). The tumor was imaged using (64)Cu-DOTA-TOC, (64)Cu-TETA-OC, and FDG with an animal PET scanner. (64)Cu-DOTA-TOC can be produced in amounts sufficient for clinical study with high radiochemical yield. (64)Cu-DOTA-TOC was stable in vitro, but time-dependent transchelation to protein was observed after injection into mice. In biodistribution studies, the radioactivity of (64)Cu was higher than that of (111)In in all organs except kidney. In tumor-bearing mice, (64)Cu-DOTA-TOC showed a high accumulation in the tumor, and the tumor-to-blood ratio reached as high as 8.81 +/- 1.17 at 6 h after administration. (64)Cu-DOTA-TOC showed significantly higher accumulation in the tumor than (64)Cu-TETA-OC. (64)Cu-DOTA-TOC PET showed a very clear image of the tumor, which was comparable to that of (18)F-FDG PET and very similar to that of (64)Cu

  2. Therapy using labelled somatostatin analogues: comparison of the absorbed doses with 111In-DTPA-D-Phe1-octreotide and yttrium-labelled DOTA-D-Phe1-Tyr3-octreotide.

    PubMed

    Barone, Raffaella; Walrand, Stéphan; Konijnenberg, Mark; Valkema, Roelf; Kvols, Larry K; Krenning, Eric P; Pauwels, Stanislas; Jamar, François

    2008-03-01

    We estimated the absorbed doses for (111)In-DTPA-D-Phe(1)-octreotide and (90)Y-DOTA-D-Phe(1)-Tyr(3)-octreotide in the same patients in order to compare the potential effectiveness (tumour dose) and safety (kidney and red marrow dose) of these drugs for peptide-targeted radiotherapy of somatostatin receptor positive tumours. Six patients with neuroendocrine tumours underwent quantitative (111)In-DTPA-D-Phe(1)-octreotide SPECT and (86)Y-DOTA-D-Phe(1)-Tyr(3)-octreotide PET scan at intervals of 1 week. All studies were performed with a co-infusion of amino acids for renal protection. PET and SPECT were reconstructed using iterative algorithms, incorporating attenuation and scatter corrections. Tissue uptakes (IA%) were measured and used to calculate residence times. Absorbed doses to tissues were estimated and the maximal allowed activity, defined as either the activity delivering 23 Gy to the kidneys (MAA(K)) or 2 Gy to the red marrow (MAA(RM)), was calculated and the resulting tumour absorbed doses were computed. For the MAA(K) the mean absorbed dose to the red marrow was lower for (90)Y-DOTA-D-Phe(1)-Tyr(3)-octreotide than for (111)In-DTPA-D-Phe(1)-octreotide (1.8+/-0.9 Gy vs. 6.4+/-1.6 Gy; P<0.001). The median absorbed dose to tumours for the MAA(K) was two-fold higher for (90)Y-DOTA-D-Phe(1)-Tyr(3)-octreotide as compared to (111)In-DTPA-D-Phe(1)-octreotide (30.1 vs. 12.6 Gy; P<0.05). The median absorbed dose to tumours estimated for the MAA(RM) was 10-fold higher for (90)Y-DOTA-D-Phe(1)-Tyr(3)-octreotide than for (111)In-DTPA-D-Phe(1)-octreotide (35.1 Gy vs. 3.9 Gy; P<0.05). This direct intra-patient comparison confirms that the use of (90)Y-DOTA-D-Phe(1)-Tyr(3)-octreotide is more appropriate for therapy of somatostatin receptor bearing tumours. When using (111)In-DTPA-D-Phe(1)-octreotide, the red marrow represents the major critical organ; this can result in significant toxicity if high activities have to be administered to obtain efficient tumour irradiation.

  3. Failure of functional imaging with gallium-68-DOTA-D-Phe1-Tyr3-octreotide positron emission tomography to localize the site of ectopic adrenocorticotropic hormone secretion: a case report

    PubMed Central

    2011-01-01

    Introduction The diagnostic efficacy of biochemical and imaging modalities for investigating the causes of Cushing's syndrome are limited. We report a case demonstrating the limitations of these modalities, especially the inability of functional imaging to help localize the site of ectopic adrenocorticotropic hormone secretion. Case presentation A 37-year-old Arabian woman presented with 12 months of progressive Cushing's syndrome-like symptoms. Biochemical evaluation confirmed adrenocorticotropic hormone -dependent Cushing's syndrome. However, the anatomical site of her excess adrenocorticotropic hormone secretion was not clearly delineated by further investigations. Magnetic resonance imaging of our patient's pituitary gland failed to demonstrate the presence of an adenoma. Spiral computed tomography of her chest only revealed the presence of a non-specific 7 mm lesion in her left inferobasal lung segment. Functional imaging, including a positron emission tomography scan using 18-fluorodeoxyglucose and gallium-68-DOTA-D-Phe1-Tyr3-octreotide, also failed to show increased metabolic activity in the lung lesion or in her pituitary gland. Our patient was commenced on medical treatment with ketoconazole and metyrapone to control the clinical features associated with her excess cortisol secretion. Despite initial normalization of her urinary free cortisol excretion rate, levels began to rise eight months after commencement of medical treatment. Repeated imaging of her pituitary gland, chest and pelvis again failed to clearly localize a source of her excess adrenocorticotropic hormone secretion. The bronchial nodule was stable in size on serial imaging and repeatedly reported as having a nonspecific appearance of a small granuloma or lymph node. We re-explored the treatment options and endorsed our patient's favored choice of resection of the bronchial nodule, especially given that her symptoms of cortisol excess were difficult to control and refractory. Subsequently

  4. In vivo biodistribution and small animal PET of (64)Cu-labeled antimicrobial peptoids.

    PubMed

    Seo, Jiwon; Ren, Gang; Liu, Hongguang; Miao, Zheng; Park, Minyoung; Wang, Yihong; Miller, Tyler M; Barron, Annelise E; Cheng, Zhen

    2012-05-16

    Peptoids are a rapidly developing class of biomimetic polymers based on oligo-N-substituted glycine backbones, designed to mimic peptides and proteins. Inspired by natural antimicrobial peptides, a group of cationic amphipathic peptoids has been successfully discovered with potent, broad-spectrum activity against pathogenic bacteria; however, there are limited studies to address the in vivo pharmacokinetics of the peptoids. Herein, (64)Cu-labeled DOTA conjugates of three different peptoids and two control peptides were synthesized and assayed in vivo by both biodistribution studies and small animal positron emission tomography (PET). The study was designed in a way to assess how structural differences of the peptidomimetics affect in vivo pharmacokinetics. As amphipathic molecules, major uptake of the peptoids occurred in the liver. Increased kidney uptake was observed by deleting one hydrophobic residue in the peptoid, and (64)Cu-3 achieved the highest kidney uptake of all the conjugates tested in this study. In comparison to peptides, our data indicated that peptoids had general in vivo properties of higher tissue accumulation, slower elimination, and higher in vivo stability. Different administration routes (intravenous, intraperitoneal, and oral) were investigated with peptoids. When administered orally, the peptoids showed poor bioavailability, reminiscent of that of peptide. However, remarkably longer passage through the gastrointestinal (GI) tract without rapid digestion was observed for peptoids. These unique in vivo properties of peptoids were rationalized by efficient cellular membrane permeability and protease resistance of peptoids. The results observed in the biodistribution studies could be confirmed by PET imaging, which provides a reliable way to evaluate in vivo pharmacokinetic properties of peptoids noninvasively and in real time. The pharmacokinetic data presented here can provide insight for further development of the antimicrobial peptoids as

  5. Evaluation of 64Cu-Labeled Acridinium Cation: A PET Radiotracer Targeting Tumor Mitochondria

    PubMed Central

    Zhou, Yang; Kim, Young-Seung; Shi, Jiyun; Jacobson, Orit; Chen, Xiaoyuan; Liu, Shuang

    2011-01-01

    This report presents the synthesis and evaluations of 64Cu(DO3A-xy-ACR) (DO3A-xy-ACR = 2,6-bis(dimethylamino)-10-(4-((4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododecan-1-yl)methyl)benzyl)acridin-10-ium) as a radiotracer for imaging tumors in athymic nude mice bearing U87MG glioma xenografts by PET (positron emission tomography). The biodistribution data suggested that 64Cu(DO3A-xy-ACR) was excreted mainly through the renal system with >65% of injected radioactivity being recovered from urine samples at 1 h post-injection (p.i.). The tumor uptake of 64Cu(DO3A-xy-ACR) was 1.07 ± 0.23, 1.58 ± 0.55, 2.71 ± 0.66, 3.47 ± 1.19, and 3.52 ± 1.72 %ID/g at 0.5, 1, 2, 4 and 24 h p.i., respectively. 64Cu(DO3A-xy-ACR) had very high liver uptake (31.90 ± 3.98, 24.95 ± 5.64, 15.20 ± 4.29, 14.09 ± 6.82, and 8.18 ± 1.27 %ID/g at 0.5, 1, 2, 4 and 24 h p.i., respectively) with low tumor/liver ratios. MicroPET studies showed that the tumors were clearly visualized as early as 30 min p.i. in the glioma-bearing mouse administered with 64Cu(DO3A-xy-ACR). The high liver radioactivity accumulation was also seen. 64Cu(DO3A-xy-ACR) had a relatively high metabolic stability during excretion via both renal and hepatobiliary routes; but it was completely decomposed in the liver homogenate. We explored the localization mechanism of Cu(DO3A-xy-ACR) using both U87MG human glioma and the cultured primary U87MG glioma cells. The results from the cellular staining assays showed that 64Cu(DO3A-xy-ACR) is able to localize in the mitochondria of living U87MG glioma cells due to the enhanced negative mitochondrial potential as compared to normal cells. Although 64Cu(DO3A-xy-ACR) is not an ideal PET radiotracer for tumor imaging due to its high liver uptake, the results from this study strongly suggest that 64Cu-labeled acridinium cations are indeed able to localize in the energized mitochondria of tumor cells. PMID:21413736

  6. A Novel PET Imaging Using 64Cu-Labeled Monoclonal Antibody against Mesothelin Commonly Expressed on Cancer Cells

    PubMed Central

    Kobayashi, Kazuko; Sasaki, Takanori; Takenaka, Fumiaki; Yakushiji, Hiromasa; Fujii, Yoshihiro; Kishi, Yoshiro; Kita, Shoichi; Shen, Lianhua; Kumon, Hiromi; Matsuura, Eiji

    2015-01-01

    Mesothelin (MSLN) is a 40-kDa cell differentiation-associated glycoprotein appearing with carcinogenesis and is highly expressed in many human cancers, including the majority of pancreatic adenocarcinomas, ovarian cancers, and mesotheliomas, while its expression in normal tissue is limited to mesothelial cells lining the pleura, pericardium, and peritoneum. Clone 11-25 is a murine hybridoma secreting monoclonal antibody (mAb) against human MSLN. In this study, we applied the 11-25 mAb to in vivo imaging to detect MSLN-expressing tumors. In in vitro and ex vivo immunochemical studies, we demonstrated specificity of 11-25 mAb to membranous MSLN expressed on several pancreatic cancer cells. We showed the accumulation of Alexa Fluor 750-labeled 11-25 mAb in MSLN-expressing tumor xenografts in athymic nude mice. Then, 11-25 mAb was labeled with 64Cu via a chelating agent DOTA and was used in both in vitro cell binding assay and in vivo positron emission tomography (PET) imaging in the tumor-bearing mice. We confirmed that 64Cu-labeled 11-25 mAb highly accumulated in MSLN-expressing tumors as compared to MSLN-negative ones. The 64Cu-labeled 11-25 mAb is potentially useful as a PET probe capable of being used for wide range of tumors, rather than 18F-FDG that occasionally provides nonspecific accumulation into the inflammatory lesions. PMID:25883990

  7. PET Imaging of Abdominal Aortic Aneurysm with 64Cu-Labeled Anti-CD105 Antibody Fab Fragment

    PubMed Central

    Shi, Sixiang; Orbay, Hakan; Yang, Yunan; Graves, Stephen A.; Nayak, Tapas R.; Hong, Hao; Hernandez, Reinier; Luo, Haiming; Goel, Shreya; Theuer, Charles P.; Nickles, Robert J.; Cai, Weibo

    2015-01-01

    The critical challenge in abdominal aortic aneurysm (AAA) research is the accurate diagnosis and assessment of AAA progression. Angiogenesis is a pathological hallmark of AAA, and CD105 is highly expressed on newly formed vessels. Our goal was to use 64Cu-labeled anti-CD105 antibody Fab fragment for noninvasive assessment of angiogenesis in the aortic wall in a murine model of AAA. Methods Fab fragment of TRC105, a mAb that specifically binds to CD105, was generated by enzymatic papain digestion and conjugated to NOTA for 64Cu-labeling. Binding affinity/specificity of NOTA-TRC105-Fab was evaluated by flow cytometry and various ex vivo studies. BALB/c mice were anesthetized and treated with calcium phosphate to induce AAA, which underwent weekly PET scans using 64Cu-NOTA-TRC105-Fab. Biodistribution and autoradiography studies were also performed to confirm the accuracy of PET results. Results NOTA-TRC105-Fab exhibited high purity and specifically bound to CD105 in vitro. Uptake of 64Cu-NOTA-TRC105-Fab increased from a control level of 3.4 ± 0.1 to 9.5 ± 0.4 %ID/g at 6 h p.i. on Day 5, and decreased to 7.2 ± 1.4 %ID/g on Day 12 which correlated well with biodistribution and autoradiography studies (i.e. much higher tracer uptake in AAA than normal aorta). Of note, enhanced AAA contrast was achieved, due to the minimal background in the abdominal area of mice. Degradation of elastic fibers and highly expressed CD105 were observed in ex vivo studies. Conclusion 64Cu-NOTA-TRC105-Fab cleared rapidly through kidneys, which enabled noninvasive PET imaging of the aorta with enhanced contrast and showed increased angiogenesis (CD105 expression) during AAA. 64Cu-NOTA-TRC105-Fab PET may potentially be used for future diagnosis and prognosis of AAA. PMID:25883125

  8. 64Cu-Labeled Inhibitors of Prostate-Specific Membrane Antigen for PET Imaging of Prostate Cancer

    PubMed Central

    2015-01-01

    Prostate-specific membrane antigen (PSMA) is a well-recognized target for identification and therapy of a variety of cancers. Here we report five 64Cu-labeled inhibitors of PSMA, [64Cu]3–7, which are based on the lysine–glutamate urea scaffold and utilize a variety of macrocyclic chelators, namely NOTA(3), PCTA(4), Oxo-DO3A(5), CB-TE2A(6), and DOTA(7), in an effort to determine which provides the most suitable pharmacokinetics for in vivo PET imaging. [64Cu]3–7 were prepared in high radiochemical yield (60–90%) and purity (>95%). Positron emission tomography (PET) imaging studies of [64Cu]3–7 revealed specific accumulation in PSMA-expressing xenografts (PSMA+ PC3 PIP) relative to isogenic control tumor (PSMA– PC3 flu) and background tissue. The favorable kinetics and high image contrast provided by CB-TE2A chelated [64Cu]6 suggest it as the most promising among the candidates tested. That could be due to the higher stability of [64Cu]CB-TE2A as compared with [64Cu]NOTA, [64Cu]PCTA, [64Cu]Oxo-DO3A, and [64Cu]DOTA chelates in vivo. PMID:24533799

  9. Small-Animal PET Imaging of Pancreatic Cancer Xenografts Using a 64Cu-Labeled Monoclonal Antibody, MAb159.

    PubMed

    Wang, Hui; Li, Dan; Liu, Shuanglong; Liu, Ren; Yuan, Hong; Krasnoperov, Valery; Shan, Hong; Conti, Peter S; Gill, Parkash S; Li, Zibo

    2015-06-01

    Overexpression of the GRP78 receptor on cell surfaces has been linked with tumor growth, metastasis, and resistance to therapy. We developed a (64)Cu-labeled probe for PET imaging of tumor GRP78 expression based on a novel anti-GRP78 monoclonal antibody, MAb159. MAb159 was conjugated with the (64)Cu-chelator DOTA through lysines on the antibody. DOTA-human IgG was also prepared as a control that did not bind to GRP78. The resulting PET probes were evaluated in BXPC3 pancreatic cancer xenografts in athymic nude mice. The radiotracer was synthesized with a specific activity of 0.8 MBq/μg of antibody. In BXPC3 xenografts, (64)Cu-DOTA-MAb159 demonstrated prominent tumor accumulation (4.3 ± 1.2, 15.4 ± 2.6, and 18.3 ± 1.0 percentage injected dose per gram at 1, 17, and 48 after injection, respectively). In contrast, (64)Cu-DOTA-human IgG had low BXPC3 tumor accumulation (4.8 ± 0.5, 7.5 ± 0.7, and 4.6 ± 0.8 percentage injected dose per gram at 1, 17, and 48 h after injection, respectively). We demonstrated that GRP78 can serve as a valid target for pancreatic cancer imaging. The success of this approach will be valuable for evaluating disease course and therapeutic efficacy at the earliest stages of anti-GRP78 treatment. Moreover, these newly developed probes may have important applications in other types of cancer overexpressing GRP78. © 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

  10. Positron Emission Tomography Imaging of CD105 Expression with a 64Cu-Labeled Monoclonal Antibody: NOTA Is Superior to DOTA

    PubMed Central

    Zhang, Yin; Hong, Hao; Engle, Jonathan W.; Bean, Jero; Yang, Yunan; Leigh, Bryan R.; Barnhart, Todd E.; Cai, Weibo

    2011-01-01

    Optimizing the in vivo stability of positron emission tomography (PET) tracers is of critical importance to cancer diagnosis. In the case of 64Cu-labeled monoclonal antibodies (mAb), in vivo behavior and biodistribution is critically dependent on the performance of the bifunctional chelator used to conjugate the mAb to the radiolabel. This study compared the in vivo characteristics of 64Cu-labeled TRC105 (a chimeric mAb that binds to both human and murine CD105), through two commonly used chelators: 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA). Flow cytometry analysis confirmed that chelator conjugation of TRC105 did not affect its CD105 binding affinity or specificity. PET imaging and biodistribution studies in 4T1 murine breast tumor-bearing mice revealed that 64Cu-NOTA-TRC105 exhibited better stability than 64Cu-DOTA-TRC105 in vivo, which resulted in significantly lower liver uptake without compromising the tumor targeting efficiency. In conclusion, this study confirmed that NOTA is a superior chelator to DOTA for PET imaging with 64Cu-labeled TRC105. PMID:22174762

  11. Positron emission tomography imaging of CD105 expression with a 64Cu-labeled monoclonal antibody: NOTA is superior to DOTA.

    PubMed

    Zhang, Yin; Hong, Hao; Engle, Jonathan W; Bean, Jero; Yang, Yunan; Leigh, Bryan R; Barnhart, Todd E; Cai, Weibo

    2011-01-01

    Optimizing the in vivo stability of positron emission tomography (PET) tracers is of critical importance to cancer diagnosis. In the case of (64)Cu-labeled monoclonal antibodies (mAb), in vivo behavior and biodistribution is critically dependent on the performance of the bifunctional chelator used to conjugate the mAb to the radiolabel. This study compared the in vivo characteristics of (64)Cu-labeled TRC105 (a chimeric mAb that binds to both human and murine CD105), through two commonly used chelators: 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA). Flow cytometry analysis confirmed that chelator conjugation of TRC105 did not affect its CD105 binding affinity or specificity. PET imaging and biodistribution studies in 4T1 murine breast tumor-bearing mice revealed that (64)Cu-NOTA-TRC105 exhibited better stability than (64)Cu-DOTA-TRC105 in vivo, which resulted in significantly lower liver uptake without compromising the tumor targeting efficiency. In conclusion, this study confirmed that NOTA is a superior chelator to DOTA for PET imaging with (64)Cu-labeled TRC105.

  12. Positron emission tomography imaging of tumor angiogenesis with a (61/64)Cu-labeled F(ab')(2) antibody fragment.

    PubMed

    Hong, Hao; Zhang, Yin; Orbay, Hakan; Valdovinos, Hector F; Nayak, Tapas R; Bean, Jero; Theuer, Charles P; Barnhart, Todd E; Cai, Weibo

    2013-02-04

    The objective of this study was to characterize the in vitro and in vivo properties of the F(ab')(2) fragment of TRC105, a human/murine chimeric IgG1 monoclonal antibody that binds with high avidity to human and murine CD105 (i.e., endoglin), and investigate its potential for positron emission tomography (PET) imaging of tumor angiogenesis after (61/64)Cu-labeling. TRC105-F(ab')(2) of high purity was produced by pepsin digestion of TRC105, which was confirmed by SDS-PAGE, HPLC analysis, and mass spectrometry. (61/64)Cu-labeling of NOTA-TRC105-F(ab')(2) (NOTA denotes 1,4,7-triazacyclononane-1,4,7-triacetic acid) was achieved with yields of >75% (specific activity: ∼115 GBq/μmol). PET imaging revealed rapid tumor uptake of (64)Cu-NOTA-TRC105-F(ab')(2) in the 4T1 murine breast cancer model (5.8 ± 0.8, 7.6 ± 0.6, 5.6 ± 0.4, 5.0 ± 0.6, and 3.8 ± 0.7% ID/g at 0.5, 3, 16, 24, and 48 h postinjection respectively; n = 4). Since tumor uptake peaked at 3 h postinjection, (61)Cu-NOTA-TRC105-F(ab')(2) also gave good tumor contrast at 3 and 8 h postinjection. CD105 specificity of the tracers was confirmed by blocking studies and histopathology. In conclusion, the use of a F(ab')(2) fragment led to more rapid tumor uptake (which peaked at 3 h postinjection) than radiolabeled intact antibody (which often peaked after 24 h postinjection), which may allow for same day immunoPET imaging in future clinical studies.

  13. Improved PET imaging of uPAR expression using new (64)Cu-labeled cross-bridged peptide ligands: comparative in vitro and in vivo studies.

    PubMed

    Persson, Morten; Hosseini, Masood; Madsen, Jacob; Jørgensen, Thomas J D; Jensen, Knud J; Kjaer, Andreas; Ploug, Michael

    2013-01-01

    The correlation between uPAR expression, cancer cell invasion and metastases is now well-established and has prompted the development of a number of uPAR PET imaging agents, which could potentially identify cancer patients with invasive and metastatic lesions. In the present study, we synthesized and characterized two new cross-bridged (64)Cu-labeled peptide conjugates for PET imaging of uPAR and performed a head-to-head comparison with the corresponding and more conventionally used DOTA conjugate. Based on in-source laser-induced reduction of chelated Cu(II) to Cu(I), we now demonstrate the following ranking with respect to the chemical inertness of their complexed Cu ions: DOTA-AE105 < CB-TE2A-AE105 < CB-TE2A-PA-AE105, which is correlated to their corresponding demetallation rate. No penalty in the uPAR receptor binding affinity of the targeting peptide was encountered by conjugation to either of the macrobicyclic chelators (IC50 ~ 5-10 nM) and high yields and radiochemical purities (>95%) were achieved in all cases by incubation at 95ºC. In vivo, they display identical tumor uptake after 1h, but differ significantly after 22 hrs, where the DOTA-AE105 uptake remains surprisingly high. Importantly, the more stable of the new uPAR PET tracers, (64)Cu-CB-TE2A-PA-AE105, exhibits a significantly reduced liver uptake compared to (64)Cu-DOTA-AE105 as well as (64)Cu-CB-TE2A-AE105, (p<0.0001), emphasizing that our new in vitro stability measurements by mass spectrometry predicts in vivo stability in mice. Specificity of the best performing ligand, (64)Cu-CB-TE2A-PA-AE105 was finally confirmed in vivo using a non-binding (64)Cu-labeled peptide as control ((64)Cu-CB-TE2A-PA-AE105(mut)). This control PET-tracer revealed significantly reduced tumor uptake (p<0.0001), but identical hepatic uptake compared to its active counterpart ((64)Cu-CB-TE2A-PA-AE105) after 1h. In conclusion, our new approach using in-source laser-induced reduction of Cu(II)-chelated PET-ligands provides

  14. Improved PET Imaging of uPAR Expression Using new 64Cu-labeled Cross-Bridged Peptide Ligands: Comparative in vitro and in vivo Studies

    PubMed Central

    Persson, Morten; Hosseini, Masood; Madsen, Jacob; Jørgensen, Thomas J. D.; Jensen, Knud J; Kjaer, Andreas; Ploug, Michael

    2013-01-01

    The correlation between uPAR expression, cancer cell invasion and metastases is now well-established and has prompted the development of a number of uPAR PET imaging agents, which could potentially identify cancer patients with invasive and metastatic lesions. In the present study, we synthesized and characterized two new cross-bridged 64Cu-labeled peptide conjugates for PET imaging of uPAR and performed a head-to-head comparison with the corresponding and more conventionally used DOTA conjugate. Based on in-source laser-induced reduction of chelated Cu(II) to Cu(I), we now demonstrate the following ranking with respect to the chemical inertness of their complexed Cu ions: DOTA-AE105 << CB-TE2A-AE105 < CB-TE2A-PA-AE105, which is correlated to their corresponding demetallation rate. No penalty in the uPAR receptor binding affinity of the targeting peptide was encountered by conjugation to either of the macrobicyclic chelators (IC50 ~ 5-10 nM) and high yields and radiochemical purities (>95%) were achieved in all cases by incubation at 95ºC. In vivo, they display identical tumor uptake after 1h, but differ significantly after 22 hrs, where the DOTA-AE105 uptake remains surprisingly high. Importantly, the more stable of the new uPAR PET tracers, 64Cu-CB-TE2A-PA-AE105, exhibits a significantly reduced liver uptake compared to 64Cu-DOTA-AE105 as well as 64Cu-CB-TE2A-AE105, (p<0.0001), emphasizing that our new in vitro stability measurements by mass spectrometry predicts in vivo stability in mice. Specificity of the best performing ligand, 64Cu-CB-TE2A-PA-AE105 was finally confirmed in vivo using a non-binding 64Cu-labeled peptide as control (64Cu-CB-TE2A-PA-AE105mut). This control PET-tracer revealed significantly reduced tumor uptake (p<0.0001), but identical hepatic uptake compared to its active counterpart (64Cu-CB-TE2A-PA-AE105) after 1h. In conclusion, our new approach using in-source laser-induced reduction of Cu(II)-chelated PET-ligands provides useful

  15. Correlation between positron emission tomography and Cerenkov luminescence imaging in vivo and ex vivo using 64Cu-labeled antibodies in a neuroblastoma mouse model

    PubMed Central

    Maier, Florian C.; Schmitt, Julia; Maurer, Andreas; Ehrlichmann, Walter; Reischl, Gerald; Nikolaou, Konstantin; Handgretinger, Rupert; Pichler, Bernd J.; Thaiss, Wolfgang M.

    2016-01-01

    Antibody-based therapies gain momentum in clinical therapy, thus the need for accurate imaging modalities with respect to target identification and therapy monitoring are of increasing relevance. Cerenkov luminescence imaging (CLI) are a novel method detecting charged particles emitted during radioactive decay with optical imaging. Here, we compare Position Emission Tomography (PET) with CLI in a multimodal imaging study aiming at the fast and efficient screening of monoclonal antibodies (mAb) designated for targeting of the neuroblastoma-characteristic epitope disialoganglioside GD2. Neuroblastoma-bearing SHO mice were injected with a 64Cu-labeled GD2-specific mAb. The tumor uptake was imaged 3 h, 24 h and 48 h after tracer injection with both, PET and CLI, and was compared to the accumulation in GD2-negative control tumors (human embryonic kidney, HEK-293). In addition to an in vivo PET/CLI-correlation over time, we also demonstrate linear correlations of CLI- and γ-counter-based biodistribution analysis. CLI with its comparably short acquisition time can thus be used as an attractive one-stop-shop modality for the longitudinal monitoring of antibody-based tumor targeting and ex vivo biodistribution. These findings suggest CLI as a reliable alternative for PET and biodistribution studies with respect to fast and high-throughput screenings in subcutaneous tumors traced with radiolabeled antibodies. However, in contrast to PET, CLI is not limited to positron-emitting isotopes and can therefore also be used for the visualization of mAb labeled with therapeutic isotopes like electron emitters. PMID:27602580

  16. In Vitro and In Vivo Evaluation of a 64Cu-Labeled NOTA-Bn-SCN-Aoc-Bombesin Analogue in Gastrin-Releasing Peptide Receptor Expressing Prostate Cancer

    PubMed Central

    Craft, Jeffrey M.; De Silva1, Ravindra A.; Lears, Kimberly A.; Andrews, Rebecca; Liang, Kexian; Achilefu, Samuel; Rogers, Buck E.

    2012-01-01

    Introduction Bombesin (BN) is an amphibian peptide that binds to the gastrin-releasing peptide receptor (GRPR). It has been demonstrated that BN analogues can be radiolabeled for potential diagnosis and treatment of GRPR-expressing malignancies. Previous studies have conjugated various chelators to the eight C-terminal amino acids of BN (BN(7-14)) for radiolabeling with 64Cu. Recently, (1,4,7-triazacyclononane-1,4,7-triacetic acid) (NOTA) has been evaluated as the five coordinate 64Cu complex with results indicating GRPR-specific tumor uptake. This study aimed to conjugate S-2-(4-isothiocyanatobenzyl)-NOTA (p-SCN-Bn-NOTA) to BN(7-14) such that it could form a six coordinate complex with 64Cu and evaluate the resulting peptide. Methods p-SCN-NOTA was conjugated to 8-aminooctanoic acid (Aoc)-BN(7-14) in solution to yield NOTA-Bn-SCN-Aoc-BN(7-14). The unlabeled peptide was evaluated in a cell binding assay using PC-3 prostate cancer cells and 125I-Tyr4-BN to determine the IC50 value. The peptide was radiolabeled with 64Cu and evaluated for internalization into PC-3 cells and for tumor uptake in mice bearing PC-3 xenografts using biodistribution and microPET imaging studies. Results The binding assay demonstrated that NOTA-Bn-SCN-Aoc-BN(7-14) bound with high affinity to GRPR with an IC50 of 1.4 nM. The radiolabeled peptide demonstrated time-dependent internalization into PC-3 cells. In vivo, the peptide demonstrated tumor-specific uptake and imaging that was comparable to that of previously reported 64Cu-labeled BN analogues. Conclusions These studies demonstrate that 64Cu-NOTA-Bn-SCN-Aoc-BN(7-14) binds to GRPR expressing cells and that it can be used for imaging of GRPR-expressing prostate cancer. PMID:22261146

  17. Targeting CD146 with a 64Cu-labeled antibody enables in vivo immunoPET imaging of high-grade gliomas

    PubMed Central

    Yang, Yunan; Hernandez, Reinier; Rao, Jun; Yin, Li; Qu, Yazhuo; Wu, Jinrong; England, Christopher G.; Graves, Stephen A.; Lewis, Christina M.; Wang, Pu; Meyerand, Mary E.; Nickles, Robert J.; Bian, Xiu-wu; Cai, Weibo

    2015-01-01

    Given the highly heterogeneous character of brain malignancies and the associated implication for its proper diagnosis and treatment, finding biomarkers that better characterize this disease from a molecular standpoint is imperative. In this study, we evaluated CD146 as a potential molecular target for diagnosis and targeted therapy of glioblastoma multiforme (GBM), the most common and lethal brain malignancy. YY146, an anti-CD146 monoclonal antibody, was generated and radiolabeled for noninvasive positron-emission tomography (PET) imaging of orthotopic GBM models. 64Cu-labeled YY146 preferentially accumulated in the tumors of mice bearing U87MG xenografts, which allowed the acquisition of high-contrast PET images of small tumor nodules (∼2 mm). Additionally, we found that tumor uptake correlated with the levels of CD146 expression in a highly specific manner. We also explored the potential therapeutic effects of YY146 on the cancer stem cell (CSC) and epithelial-to-mesenchymal (EMT) properties of U87MG cells, demonstrating that YY146 can mitigate those aggressive phenotypes. Using YY146 as the primary antibody, we performed histological studies of World Health Organization (WHO) grades I through IV primary gliomas. The positive correlation found between CD146-positive staining and high tumor grade (χ2 = 9.028; P = 0.029) concurred with the GBM data available in The Cancer Genome Atlas (TCGA) and validated the clinical value of YY146. In addition, we demonstrate that YY146 can be used to detect CD146 in various cancer cell lines and human resected tumor tissues of multiple other tumor types (gastric, ovarian, liver, and lung), indicating a broad applicability of YY146 in solid tumors. PMID:26553993

  18. Correlation between positron emission tomography and Cerenkov luminescence imaging in vivo and ex vivo using 64Cu-labeled antibodies in a neuroblastoma mouse model.

    PubMed

    Maier, Florian C; Schmitt, Julia; Maurer, Andreas; Ehrlichmann, Walter; Reischl, Gerald; Nikolaou, Konstantin; Handgretinger, Rupert; Pichler, Bernd J; Thaiss, Wolfgang M

    2016-10-11

    Antibody-based therapies gain momentum in clinical therapy, thus the need for accurate imaging modalities with respect to target identification and therapy monitoring are of increasing relevance. Cerenkov luminescence imaging (CLI) are a novel method detecting charged particles emitted during radioactive decay with optical imaging. Here, we compare Position Emission Tomography (PET) with CLI in a multimodal imaging study aiming at the fast and efficient screening of monoclonal antibodies (mAb) designated for targeting of the neuroblastoma-characteristic epitope disialoganglioside GD2. Neuroblastoma-bearing SHO mice were injected with a 64Cu-labeled GD2-specific mAb. The tumor uptake was imaged 3 h, 24 h and 48 h after tracer injection with both, PET and CLI, and was compared to the accumulation in GD2-negative control tumors (human embryonic kidney, HEK-293). In addition to an in vivo PET/CLI-correlation over time, we also demonstrate linear correlations of CLI- and γ-counter-based biodistribution analysis. CLI with its comparably short acquisition time can thus be used as an attractive one-stop-shop modality for the longitudinal monitoring of antibody-based tumor targeting and ex vivo biodistribution.These findings suggest CLI as a reliable alternative for PET and biodistribution studies with respect to fast and high-throughput screenings in subcutaneous tumors traced with radiolabeled antibodies. However, in contrast to PET, CLI is not limited to positron-emitting isotopes and can therefore also be used for the visualization of mAb labeled with therapeutic isotopes like electron emitters.

  19. In vitro and in vivo evaluation of a 64Cu-labeled NOTA-Bn-SCN-Aoc-bombesin analogue in gastrin-releasing peptide receptor expressing prostate cancer.

    PubMed

    Craft, Jeffrey M; De Silva, Ravindra A; Lears, Kimberly A; Andrews, Rebecca; Liang, Kexian; Achilefu, Samuel; Rogers, Buck E

    2012-07-01

    Bombesin (BN) is an amphibian peptide that binds to the gastrin-releasing peptide receptor (GRPR). It has been demonstrated that BN analogues can be radiolabeled for potential diagnosis and treatment of GRPR-expressing malignancies. Previous studies have conjugated various chelators to the eight C-terminal amino acids of BN [BN(7-14)] for radiolabeling with 64Cu. Recently, (1,4,7-triazacyclononane-1,4,7-triacetic acid) (NOTA) has been evaluated as the five-coordinate 64Cu complex, with results indicating GRPR-specific tumor uptake. This study aimed to conjugate S-2-(4-isothiocyanatobenzyl)-NOTA (p-SCN-Bn-NOTA) to BN(7-14) such that it could form a six-coordinate complex with 64Cu and to evaluate the resulting peptide. p-SCN-NOTA was conjugated to 8-aminooctanoic acid (Aoc)-BN(7-14) in solution to yield NOTA-Bn-SCN-Aoc-BN(7-14). The unlabeled peptide was evaluated in a cell binding assay using PC-3 prostate cancer cells and 125I-Tyr4-BN to determine the IC50 value. The peptide was radiolabeled with 64Cu and evaluated for internalization into PC-3 cells and for tumor uptake in mice bearing PC-3 xenografts using biodistribution and micro-positron emission tomography imaging studies. The binding assay demonstrated that NOTA-Bn-SCN-Aoc-BN(7-14) bound with high affinity to GRPR with an IC50 of 1.4 nM. The radiolabeled peptide demonstrated time-dependent internalization into PC-3 cells. In vivo, the peptide demonstrated tumor-specific uptake and imaging that were comparable to those of previously reported 64Cu-labeled BN analogues. These studies demonstrate that 64Cu-NOTA-Bn-SCN-Aoc-BN(7-14) binds to GRPR-expressing cells and that it can be used for imaging of GRPR-expressing prostate cancer. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. Preparation and biological evaluation of (64)Cu labeled Tyr(3)-octreotate using a phosphonic acid-based cross-bridged macrocyclic chelator.

    PubMed

    Guo, Yunjun; Ferdani, Riccardo; Anderson, Carolyn J

    2012-07-18

    Somatostatin receptors (SSTr) are overexpressed in a wide range of neuroendocrine tumors, making them excellent targets for nuclear imaging and therapy, and radiolabeled somatostatin analogues have been investigated for positron emission tomography imaging and radionuclide therapy of SSTr-positive tumors, especially of the subtype-2 (SSTr2). The aim of this study was to develop a somatostatin analogue, Tyr(3)-octreotate (Y3-TATE), conjugated to a novel cross-bridged macrocyclic chelator, 11-carboxymethyl-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane-4-methanephosphonic acid (CB-TE1A1P). Unlike traditional cross-bridged macrocycles, such as 4,11-bis(carboxymethyl)-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane (CB-TE2A), CB-TE1A1P-Y3-TATE was radiolabeled with (64)Cu in high purity and high specific activity using mild conditions. Saturation binding assays revealed that (64)Cu-CB-TE1A1P-Y3-TATE had comparable binding affinity but bound to more binding sites in AR42J rat pancreatic tumor cell membranes than (64)Cu-CB-TE2A-Y3-TATE. Both radiopharmaceuticals showed comparable uptake in SSTr2 positive tissues in AR42J tumor-bearing rats. (64)Cu-CB-TE1A1P-Y3-TATE demonstrated improved blood clearance compared to (64)Cu-CB-TE2A-Y3-TATE, as the tumor/blood ratios of (64)Cu-CB-TE1A1P-Y3-TATE were shown to be significantly higher than those of (64)Cu-CB-TE2A-Y3-TATE at 4 and 24 h postinjection. (64)Cu-CB-TE1A1P-Y3-TATE, in spite of a relatively high kidney uptake, accumulated less in nontarget organs such as liver, lung, and bone. Small animal PET/CT imaging of (64)Cu-CB-TE1A1P-Y3-TATE in AR42J tumor bearing rats validated significant uptake and good contrast in the tumor. This study suggests that CB-TE1A1P is a promising bifunctional chelator for (64)Cu-labeled for Y3-TATE, owing to high binding affinity and target tissue uptake, the ability to radiolabel the agent at lower temperatures, and improved tumor/nontarget organ ratios over (64)Cu-CB-TE2A-Y3-TATE.

  1. In Vitro and In Vivo Evaluation of 64Cu-Labeled SarAr-Bombesin Analogs in Gastrin-Releasing Peptide Receptor–Expressing Prostate Cancer

    PubMed Central

    Lears, Kimberly A.; Ferdani, Riccardo; Liang, Kexian; Zheleznyak, Alexander; Andrews, Rebecca; Sherman, Christopher D.; Achilefu, Samuel; Anderson, Carolyn J.; Rogers, Buck E.

    2011-01-01

    internalization into PC-3 cells. In vivo, the radiolabeled peptides demonstrated tumor-specific uptake (13.0 and 8.5 percentage injected dose per gram for 64Cu-SarAr-SA-Aoc-bombesin(7–14) and 64Cu-SarAr-SA-Aoc-GSG-bombesin(7–14), respectively, at 1 h) and imaging that was comparable to, or better than, that of the previously reported 64Cu-labeled bombesin analogs. The 64Cu-SarAr-SA-Aoc-GSG-bombesin(7–14) had more rapid blood clearance and lower tumor and normal-tissue uptake than 64Cu-SarAr-SA-Aoc-bombesin(7–14), resulting in similar tumor-to-blood ratios for each analog (15.1 vs. 11.3 for 64Cu-SarAr-SA-Aoc-bombesin(7–14) and 64Cu-SarAr-SA-Aoc-GSG-bombesin(7–14), respectively, at 1 h). Conclusion These studies demonstrate that 64Cu-SarAr-SA-Aoc-bombesin(7–14) and 64Cu-SarAr-SA-Aoc-GSG-bombesin(7–14) bound with high affinity to GRPR-expressing cells and that these peptides can be used for PET of GRPR-expressing prostate cancer. PMID:21321264

  2. Positron emission tomography/computed tomographic and magnetic resonance imaging in a murine model of progressive atherosclerosis using (64)Cu-labeled glycoprotein VI-Fc.

    PubMed

    Bigalke, Boris; Phinikaridou, Alkystis; Andia, Marcelo E; Cooper, Margaret S; Schuster, Andreas; Schönberger, Tanja; Griessinger, Christoph M; Wurster, Thomas; Onthank, David; Ungerer, Martin; Gawaz, Meinrad; Nagel, Eike; Botnar, Rene M

    2013-11-01

    Plaque erosion leads to exposure of subendothelial collagen, which may be targeted by glycoprotein VI (GPVI). We aimed to detect plaque erosion using (64)Cu-labeled GPVI-Fc (fragment crystallized). Four-week-old male apolipoprotein E-deficient (ApoE(-/-)) mice (n=6) were fed a high-fat diet for 12 weeks. C57BL/6J wild-type (WT) mice served as controls (n=6). Another group of WT mice received a ligation injury of the left carotid artery (n=6) or sham procedure (n=4). All mice received a total activity of ≈12 MBq (64)Cu-GPVI-Fc by tail vein injection followed by delayed (24 hours) positron emission tomography using a NanoPET/computed tomographic scanner (Mediso, Hungary; Bioscan, USA) with an acquisition time of 1800 seconds. Seventy-two hours after positron emission tomography/computed tomography, all mice were scanned 2 hours after intravenous administration of 0.2 mmol/kg body weight of a gadolinium-based elastin-specific MR contrast agent. MRI was performed on a 3-T clinical scanner (Philips Healthcare, Best, The Netherlands). In ApoE(-/-) mice, the (64)Cu-GPVI-Fc uptake in the aortic arch was significantly higher compared with WT mice (ApoE(-/-): 13.2±1.5 Bq/cm(3) versus WT mice: 5.1±0.5 Bq/cm(3); P=0.028). (64)Cu-GPVI-Fc uptake was also higher in the injured left carotid artery wall compared with the intact right carotid artery of WT mice and as a trend compared with sham procedure (injured: 20.7±1.3 Bq/cm(3) versus intact: 2.3±0.5 Bq/cm(3); P=0.028 versus sham: 12.7±1.7 Bq/cm(3); P=0.068). Results were confirmed by ex vivo histology and in vivo MRI with elastin-specific MR contrast agent that measures plaque burden and vessel wall remodeling. Higher R1 relaxation rates were found in the injured carotid wall with a T1 mapping sequence (injured: 1.44±0.08 s(-1) versus intact: 0.91±0.02 s(-1); P=0.028 versus sham: 0.97±0.05 s(-1); P=0.068) and in the aortic arch of ApoE(-/-) mice compared with WT mice (ApoE(-/-): 1.49±0.05 s(-1) versus WT: 0.92±0.04 s

  3. (64)Cu-Labeled Trastuzumab Fab-PEG24-EGF Radioimmunoconjugates Bispecific for HER2 and EGFR: Pharmacokinetics, Biodistribution, and Tumor Imaging by PET in Comparison to Monospecific Agents.

    PubMed

    Kwon, Luke Yongkyu; Scollard, Deborah A; Reilly, Raymond M

    2017-02-06

    Heterodimerization of EGFR with HER2 coexpressed in breast cancer (BC) promotes tumor growth, and increased EGFR expression is associated with trastuzumab resistance. Our aim was to construct (64)Cu-labeled bispecific radioimmunoconjugates (bsRIC) composed of trastuzumab Fab, which binds HER2 linked through a polyethylene glycol (PEG24) spacer to EGF, and to compare their pharmacokinetic, biodistribution, and tumor imaging characteristics by positron-emission tomography (PET). bsRICs were generated by linking maleimide modified trastuzumab Fab with thiolated EGF through a thioether bond. HER2 and EGFR binding were assessed in vitro in MDA-MB-231 (EGFR(mod)/HER2(low)), MDA-MB-468 (EGFR(high)/HER2(neg)), MDA-MB-231-H2N (EGFR(mod)/HER2(mod)), and SKOV3 (EGFR(low)/HER2(high)) cells by competition and saturation cell binding assays to estimate the dissociation constant (Kd). The elimination of the (64)Cu-NOTA-trastuzumab Fab-PEG24-EGF bsRICs from the blood of Balb/c mice was compared to monospecific (64)Cu-NOTA-trastuzumab Fab and (64)Cu-NOTA-EGF. MicroPET/CT imaging was performed in NOD/SCID mice bearing subcutaneous MDA-MB-468, MDA-MB-231/H2N, or SKOV3 human BC xenografts at 24 and 48 h postinjection (p.i.) of bsRICs. Tumor and normal tissue uptake were quantified by biodistribution studies and compared to monospecific agents. The binding of bsRICs to MDA-MB-231 cells was decreased to 24.5 ± 5.2% by excess EGF, while the binding of bsRICs to SKOV3 cells was decreased to 38.6 ± 5.4% by excess trastuzumab Fab, demonstrating specific binding to both EGFR and HER2. (64)Cu-labeled bsRICs incorporating the PEG24 spacer were eliminated more slowly from the blood than (64)Cu-bsRICs without the PEG spacer and were cleared much more slowly than (64)Cu-NOTA-Fab or (64)Cu-NOTA-EGF. All three tumor xenografts were visualized by microPET/CT at 24 and 48 h p.i. of bsRICs. Biodistribution studies at 48 h p.i. in NOD/SCID mice with MDA-MB-231/H2N tumors demonstrated significantly

  4. PET of c-Met in cancer with 64Cu-labeled Hepatocyte Growth Factor

    PubMed Central

    Luo, Haiming; Hong, Hao; Slater, Michael R.; Graves, Stephen A.; Shi, Sixiang; Yang, Yunan; Nickles, Robert J.; Fan, Frank; Cai, Weibo

    2015-01-01

    The hepatocyte growth factor (HGF) and its receptor, c-Met, are actively involved in tumor progression/metastasis and associated closely with poor prognostic outcome of cancer patients. Thus developing positron emission tomography (PET) agents for assessing c-Met expression would be extremely useful for diagnosis of cancer and subsequent monitoring of responses to c-Met-targeted therapies. Here we report the characterization of recombinant human hepatocyte growth factor (rh-HGF) as a PET tracer for detection of c-Met expression in vivo. Methods rh-HGF was expressed in human embryonic kidney (HEK) 293 cells and purified by nickel-nitrilogriacetic acid (Ni-NTA) affinity chromatography. The concentrated rh-HGF was conjugated to 2-S-(4-isothiocyanatobenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid (p-SCN-Bn-NOTA) and labeled with 64Cu. c-Met binding evaluation by flow cytometry was performed in both U87MG and MDA-MB-231 cell lines, which have high and low level of c-Met, respectively. PET imaging and biodistribution studies were performed in nude mice bearing U87MG and MDA-MB-231 xenografted tumors. Results The rh-HGF expression yield was 150–200 µg protein per 5 × 106 cells after 48 h transfection with purity of 85% ~ 90%. Flow cytometry examination confirmed strong and specific binding capacity of rh-HGF to c-Met. After labeled with 64Cu, PET imaging revealed specific and prominent uptake of 64Cu-NOTA-rh-HGF in c-Met positive U87MG tumors (6.7 ± 1.8 %ID/g at 9 h post-injection) and significantly lower uptake in c-Met negative MDA-MB-231 tumors (1.8 ± 0.6 %ID/g at 9 h post-injection). The fact that sonicated-denatured rh-HGF (termed as dnrh-HGF) had significantly lower uptake in U87MG tumors, along with histology analysis, confirmed the c-Met specificity of 64Cu-NOTA-rh-HGF. Conclusion The study provided the initial evidence to confirm that 64Cu-NOTA-rh-HGF is applicable for visualizing c-Met expression in vivo, which may also find potential applications in treatment monitoring of c-Met-targeted cancer therapy. PMID:25840981

  5. PET Imaging of VEGFR-2 Expression in Lung Cancer with 64Cu-Labeled Ramucirumab

    PubMed Central

    Luo, Haiming; England, Christopher G.; Graves, Stephen A.; Sun, Haiyan; Liu, Glenn; Nickles, Robert J.; Cai, Weibo

    2015-01-01

    Lung cancer accounts for 17% of cancer-related deaths worldwide, and most patients present with locally advanced or metastatic disease. Novel PET imaging agents for assessing vascular endothelial growth factor receptor-2 (VEGFR-2) expression can be used for detecting VEGFR-2–positive malignancies and subsequent monitoring of therapeutic response to VEGFR-2–targeted therapies. Here, we report the synthesis and characterization of the antibody-based imaging agent for PET imaging of VEGFR-2 expression in vivo. Methods Ramucirumab (named RamAb), a fully humanized IgG1 monoclonal antibody, was conjugated to 2-S-(4-isothiocyanatobenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid (p-SCN-Bn-NOTA) and labeled with 64Cu. Flow cytometry analysis and microscopy studies were performed to compare the VEGFR-2 binding affinity of RamAb and NOTA-RamAb. PET imaging and biodistribution studies were performed in nude mice bearing HCC4006 and A549 xenograft tumors. Ex vivo histopathology was performed to elucidate the expression patterns of VEGFR-2 in different tissues and organs to validate in vivo results. Results Flow cytometry examination revealed the specific binding capacity of FITC-RamAb to VEGFR-2, and no difference in VEGFR-2 binding affinity was seen between RamAb and NOTA-RamAb. After being labeled with 64Cu, PET imaging revealed specific and prominent uptake of 64Cu-NOTA-RamAb in VEGFR-2–positive HCC4006 tumors (9.4 ± 0.5 percentage injected dose per gram at 48 h after injection; n = 4) and significantly lower uptake in VEGFR-2–negative A549 tumors (4.3 ± 0.2 percentage injected dose per gram at 48 h after injection; n = 3). Blocking experiments revealed significantly lower uptake in HCC4006 tumors, along with histology analysis, further confirming the VEGFR-2 specificity of 64Cu-NOTA-RamAb. Conclusion This study provides initial evidence that 64Cu-NOTA-RamAb can function as a PET imaging agent for visualizing VEGFR-2 expression in vivo, which may also find potential applications in monitoring the treatment response of VEGFR-2 targeted cancer therapy. PMID:26541778

  6. Design, synthesis and 64Cu labeling of fatty acid analogs containing dithiosemicarbazone chelate.

    PubMed

    Arano, Y; Magata, Y; Horiuchi, K; Matsumoto, K; Fujibayashi, Y; Ohmomo, Y; Tanaka, C; Saji, H; Yokoyama, A

    1989-01-01

    For the development of 62Cu labeled fatty acid analogs, two fatty acid analogs, containing dithiosemicarbazone (DTS) molecule as the 62Cu coordinating site, were designed and synthesized: a fatty acid analog containing DTS molecule at the omega-position, (a) the 12,13-dioxotetradecanoic acid di(N-methyl-thiosemicarbazone) (FA-DTS), and an omega-phenyl fatty acid analog containing DTS molecule at the para-position, (b) the p-carboxyundecylphenylglyoxal-di (N-methylthiosemicarbazone] (PFA-DTS). FA-DTS was synthesized by the reaction of ethyl diethoxyacetate with ethyl 11-bromonundecanate by successive decarboxylation and hydrolysis and final condensation with N-methylthiosemicarbazide. PFA-DTS was synthesized by the Friedel-Craft acylation of ethyl 11-phenylundecanate, selenium oxidation of the acetophenone derivative, followed by the condensation with N-methylthiosemicarbazide. Radiolabeling of FA-DTS and PFA-DTS with [64Cu]copper acetate was simple, rapid and quantitative. When injected into mice, both compounds were distributed and retained in the myocardium. These results offer a good basis for further development of 62Cu labeled fatty acid analogs.

  7. Imaging of Prostate Cancer Using (64)Cu-Labeled Prostate-Specific Membrane Antigen Ligand.

    PubMed

    Singh, Aviral; Kulkarni, Harshad R; Baum, Richard P

    2017-04-01

    Prostate cancer is the most common noncutaneous cancer among men, rendering the diagnosis and staging of significant medical and public interest. One of the most interesting developments in the application of nuclear oncology has been the development of novel diagnostic agents that are able to facilitate targeted therapies using the concept of theranostics. This review summarizes the current and emerging molecular imaging techniques for the investigation of patients with prostate cancer with emphasis on the potential of (64)Cu-PSMA PET/CT in staging, restaging, and the application of theranostics.

  8. PET/CT Based In Vivo Evaluation of 64Cu Labelled Nanodiscs in Tumor Bearing Mice

    PubMed Central

    Huda, Pie; Binderup, Tina; Pedersen, Martin Cramer; Midtgaard, Søren Roi; Elema, Dennis Ringkjøbing; Kjær, Andreas; Jensen, Mikael; Arleth, Lise

    2015-01-01

    64Cu radiolabelled nanodiscs based on the 11 α-helix MSP1E3D1 protein and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine lipids were, for the first time, followed in vivo by positron emission tomography for evaluating the biodistribution of nanodiscs. A cancer tumor bearing mouse model was used for the investigations, and it was found that the approximately 13 nm nanodiscs, due to their size, permeate deeply into cancer tissue. This makes them promising candidates for both drug delivery purposes and as advanced imaging agents. For the radiolabelling, a simple approach for 64Cu radiolabelling of proteins via a chelating agent, DOTA, was developed. The reaction was performed at sufficiently mild conditions to be compatible with labelling of the protein part of a lipid-protein particle while fully conserving the particle structure including the amphipathic protein fold. PMID:26132074

  9. Normal uptake of 68Ga-DOTA-TOC by the pancreas uncinate process mimicking malignancy at somatostatin receptor PET.

    PubMed

    Jacobsson, Hans; Larsson, Patricia; Jonsson, Cathrine; Jussing, Emma; Grybäck, Per

    2012-04-01

    To characterize a commonly occurring increased uptake by the uncinate process of the pancreas at PET/CT using 68Ga-DOTA-d-Phe1-Tyr3-octreotide (68Ga-DOTA-TOC). This tracer has replaced In pentetreotide (OctreoScan®) for somatostatin receptor scintigraphy at our laboratory. Fifty of our first 74 PET/CT examinations with 68Ga-DOTA-TOC could be evaluated in retrospect. None of these patients had surgery or showed any pathology in the pancreas head at the concomitant CT. Thirty-five of the 50 examinations (70%) showed an uptake by the uncinate process sufficiently intense to be interpreted as pathologic and simulating a tumor. Mean SUVmax was 9.2. Mean SUVmean using an isoactivity cut-off of >75% and >50% was 7.8 and 6.0, respectively. Volume calculations of the uncinate process activity using these definitions gave 0.9 mL and 4.2 mL, respectively. There is a frequent physiological uptake of 68Ga-DOTA-TOC by the pancreas uncinate process. This may be caused by an accumulation of pancreatic polypeptide-containing cells expressing somatostatin receptors. If there is a normal finding at concomitant diagnostic CT, this uptake should be regarded as physiological.

  10. 64Cu-Labeled LyP-1-Dendrimer for PET-CT Imaging of Atherosclerotic Plaque

    PubMed Central

    2015-01-01

    The ability to detect and quantify macrophage accumulation can provide important diagnostic and prognostic information for atherosclerotic plaque. We have previously shown that LyP-1, a cyclic 9-amino acid peptide, binds to p32 proteins on activated macrophages, facilitating the visualization of atherosclerotic plaque with PET. Yet, the in vivo plaque accumulation of monomeric [18F]FBA-LyP-1 was low (0.31 ± 0.05%ID/g). To increase the avidity of LyP-1 constructs to p32, we synthesized a dendritic form of LyP-1 on solid phase using lysine as the core structural element. Imaging probes (FAM or 6-BAT) were conjugated to a lysine or cysteine on the dendrimer for optical and PET studies. The N-terminus of the dendrimer was further modified with an aminooxy group in order to conjugate LyP-1 and ARAL peptides bearing a ketone. Oxime ligation of peptides to both dendrimers resulted in (LyP-1)4- and (ARAL)4-dendrimers with optical (FAM) and PET probes (6-BAT). For PET-CT studies, (LyP-1)4- and (ARAL)4-dendrimer-6-BAT were labeled with 64Cu (t1/2 = 12.7 h) and intravenously injected into the atherosclerotic (ApoE–/–) mice. After two hours of circulation, PET-CT coregistered images demonstrated greater uptake of the (LyP-1)4-dendrimer-64Cu than the (ARAL)4-dendrimer-64Cu in the aortic root and descending aorta. Ex vivo images and the biodistribution acquired at three hours after injection also demonstrated a significantly higher uptake of the (LyP-1)4-dendrimer-64Cu (1.1 ± 0.26%ID/g) than the (ARAL)4-dendrimer-64Cu (0.22 ± 0.05%ID/g) in the aorta. Similarly, subcutaneous injection of the LyP-1-dendrimeric carriers resulted in preferential accumulation in plaque-containing regions over 24 h. In the same model system, ex vivo fluorescence images within aortic plaque depict an increased accumulation and penetration of the (LyP-1)4-dendrimer-FAM as compared to the (ARAL)4-dendrimer-FAM. Taken together, the results suggest that the (LyP-1)4-dendrimer can be applied for in vivo PET imaging of plaque and that LyP-1 could be further exploited for the delivery of therapeutics with multivalent carriers or nanoparticles. PMID:24433095

  11. The somatostatin receptor-targeted radiotherapeutic [90Y-DOTA-DPhe1, Tyr3]octreotide (90Y-SMT 487) eradicates experimental rat pancreatic CA 20948 tumours.

    PubMed

    Stolz, B; Weckbecker, G; Smith-Jones, P M; Albert, R; Raulf, F; Bruns, C

    1998-07-01

    Somatostatin receptor-expressing tumours are potential targets for therapy with radiolabelled somatostatin analogues. We have synthesized a number of such analogues in the past and identified [DOTA-dPhe1, Tyr3]octreotide (SMT 487) as the most promising candidate molecule because of its advantageous properties in cellular and in vivo tumour models. In the current paper we describe the radiotherapeutic effect of yttrium-90 labelled SMT 487 in Lewis rats bearing the somatostatin receptor-positive rat pancreatic tumour CA 20948. SMT 487 binds with nanomolar affinity to both the human and the rat somatostatin receptor subtype 2 (sst2) (human sst2 IC50=0.9 nM, rat sst2 IC50=0.5 nM). In vivo, 90Y-SMT 487 distributed rapidly to the sst2 expressing CA 20948 rat pancreatic tumour, with a tumour-to-blood ratio of 49.15 at 24 h post injection. A single intravenous administration of 10 mCi/kg 90Y-SMT 487 resulted in a complete remission of the tumours in five out of seven CA 20948 tumour-bearing Lewis rats. No regrowth of the tumours occurred 8 months post injection. Control animals that were treated with 30 microg/kg of unlabelled SMT 487 had to be sacrificed 10 days post injection due to excessive growth or necrotic areas on the tumour surface. Upon re-inoculation of tumour cells into those rats that had shown complete remission, the tumours disappeared after 3-4 weeks of moderate growth without any further treatment. The present study shows for the first time the curative potential of 90Y-SMT 487-based radiotherapy for somatostatin receptor-expressing tumours. Clinical phase I studies with yttrium-labelled SMT 487 have started in September 1997.

  12. [68Ga]-DOTATOC-PET/CT for meningioma IMRT treatment planning

    PubMed Central

    2009-01-01

    Purpose The observation that human meningioma cells strongly express somatostatin receptor (SSTR 2) was the rationale to analyze retrospectively in how far DOTATOC PET/CT is helpful to improve target volume delineation for intensity modulated radiotherapy (IMRT). Patients and Methods In 26 consecutive patients with preferentially skull base meningioma, diagnostic magnetic resonance imaging (MRI) and planning-computed tomography (CT) was complemented with data from [68Ga]-DOTA-D Phe1-Tyr3-Octreotide (DOTATOC)-PET/CT. Image fusion of PET/CT, diagnostic computed tomography, MRI and radiotherapy planning CT as well as target volume delineation was performed with OTP-Masterplan®. Initial gross tumor volume (GTV) definition was based on MRI data only and was secondarily complemented with DOTATOC-PET information. Irradiation was performed as EUD based IMRT, using the Hyperion Software package. Results The integration of the DOTATOC data led to additional information concerning tumor extension in 17 of 26 patients (65%). There were major changes of the clinical target volume (CTV) which modify the PTV in 14 patients, minor changes were realized in 3 patients. Overall the GTV-MRI/CT was larger than the GTV-PET in 10 patients (38%), smaller in 13 patients (50%) and almost the same in 3 patients (12%). Most of the adaptations were performed in close vicinity to bony skull base structures or after complex surgery. Median GTV based on MRI was 18.1 cc, based on PET 25.3 cc and subsequently the CTV was 37.4 cc. Radiation planning and treatment of the DOTATOC-adapted volumes was feasible. Conclusion DOTATOC-PET/CT information may strongly complement patho-anatomical data from MRI and CT in cases with complex meningioma and is thus helpful for improved target volume delineation especially for skull base manifestations and recurrent disease after surgery. PMID:19922642

  13. Radiolabeling of DOTATOC with the long-lived positron emitter 44Sc.

    PubMed

    Pruszyński, Marek; Majkowska-Pilip, Agnieszka; Loktionova, Natalia S; Eppard, Elisabeth; Roesch, Frank

    2012-06-01

    The positron-emitting radionuclide (44)Sc with a half-life of 3.97 h and a β(+) branching of 94.3% is of potential interest for clinical PET. As so far it is available from a (44)Ti/(44)Sc generator in Mainz, where long-lived (44)Ti decays to no-carrier-added (nca) (44)Sc. The (44)Sc is a trivalent metal cation and should be suitable for complexation with many well established bifunctional chelators conjugated to peptides or other molecular targeting vectors. Thus, the aim of this work was to investigate the potential of (44)Sc for labeling of DOTA-conjugated peptides. DOTA-D-Phe(1)-Tyr(3)-octreotide (DOTATOC) was used as a model molecule to study and optimize labeling procedure. Reaction parameters such as buffer conditions, concentration of peptide, pH range, reaction temperature and time were optimized. Addition of 21 nmol of DOTATOC to (44)Sc in ammonium acetate buffer pH 4.0 provided labeling yields >98% within 25 min of heating in an oil-bath at 95°C. This time can be reduced to 3 min only by applying microwave supported heating. (44)Sc-DOTATOC was found to be stable in 0.9% NaCl, PBS pH 7.4, fetal calf and human serums, and also in the presence of competing metal cations (Fe(3+), Ca(2+), Cu(2+), Mg(2+)), as well as other ligand competitors, like EDTA and DTPA, even after almost 25 h incubation at 37°C. Present study shows that nca (44)Sc forms stable complexes with the macrocyclic ligand DOTA and that (44)Sc-DOTATOC and analog targeting vectors may be synthesized for further preclinical and clinical investigations. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Microwave-supported preparation of (68)Ga bioconjugates with high specific radioactivity.

    PubMed

    Velikyan, I; Beyer, G J; Långström, B

    2004-01-01

    The generator-produced positron-emitting (68)Ga (T(1/2) = 68 min) is of potential interest for clinical PET. (68)Ga as a metallic cation is suitable for complexation reactions with chelators, naked or conjugated, with peptides or other macromolecules. Large (68)Ga generator eluate volumes, metal traces from the generator column material, or reaction reagents, however, disturb a fast, reliable, and quantitative labeling procedure. In this paper we describe a simple technique, based on anion exchange, aiming first, to increase the (68)Ga concentration, second to purify it from competing impurities, and third to obtain a fast and quantitative (68)Ga-labeled peptide conjugate that can be applied in humans without further purification. Within 5 min one can obtain from the original 6 mL generator eluate a 200 microL (68)Ga preparation (volume reduction by a factor 30) that is suitable for direct and quantitative labeling of peptide conjugates. DOTATOC (DOTA-D-Phe(1)-Tyr(3)-octreotide, DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) was used as a test tracer for comparing the labeling properties of the different (68)Ga preparations. In combination with microwave heating, peptide conjugates of 0.5-1 nmol quantities could be labeled within 10 min with the full (68)Ga activity of a generator. Further purification of the (68)Ga-labeled peptide conjugate was no longer required since the nuclide incorporation was quantitative. The specific radioactivity (with respect to the peptide) was improved by a factor approximately 100 compared to the previously applied techniques using the original generator eluate. The commercial (68)Ge/(68)Ga generator from Obninsk in combination with this system for purification and concentration with an integrated microwave-supported labeling technology resulted in a kitlike technology for (68)Ga-tracer production. The first automated prototype using this technology is being tested.

  15. Early efficacy of and toxicity from lutetium-177-DOTATATE treatment in patients with progressive metastatic NET.

    PubMed

    Pencharz, Deborah; Walker, Martin; Yalchin, Mehmet; Quigley, Ann-Marie; Caplin, Martyn; Toumpanakis, Christos; Navalkissoor, Shaunak

    2017-07-01

    Lutetium-177 DOTA-D-Phe1-Tyr3-octreotide (Lu-DOTATATE) is a treatment option for patients with well-differentiated metastatic neuroendocrine tumours. Our centre started administering this therapy in 2012. The aim of this study was therefore to analyse the first cohort of patients treated with Lu-DOTATATE to determine its early efficacy and toxicity. We retrospectively analysed patient, tumour and treatment characteristics, end-of-treatment outcome, time to progression and toxicity in 79 consecutive patients treated with Lu-DOTATATE who had progressive NET according to Response Evaluation Criteria in Solid Tumours criteria. Follow-up time was 12-40 months. Study of Kaplan-Meier plots, analysis of time to progression and multiple regression analysis of factors predictive of time to progression were performed. At end-of-treatment radiological restaging, 13% of patients were found to have partial response and 64% to have stable disease; 23% of patients progressed through treatment. Overall, 47% of patients demonstrated a reduction in chromogranin A levels. The overall estimated median time to progression from the start of treatment was 28 months for the entire cohort and 31, 30 and 5 months for those with partial response, stable disease and progressive disease, respectively. On multivariate regression analysis, higher grade of tumour was found to be significantly associated with shorter progression-free survival. Three patients experienced grade 1 haematotoxicity, five grade 1 nephrotoxicity and one grade 2 nephrotoxicity. Early outcomes of patients treated with Lu-DOTATATE are similar to those in previously published series in terms of end-of-treatment efficacy and toxicity. This provides further evidence that this is a safe and efficacious form of treatment for patients with progressive metastatic neuroendocrine tumours.

  16. Synthesis, Cu(II) complexation, 64Cu-labeling and biological evaluation of cross-bridged cyclam chelators with phosphonate pendant arms†

    PubMed Central

    Ferdani, Riccardo; Stigers, Dannon J.; Fiamengo, Ashley L.; Wei, Lihui; Li, Barbara T. Y.; Golen, James A.; Rheingold, Arnold L.; Weisman, Gary R.; Wong, Edward H.; Anderson, Carolyn J.

    2012-01-01

    A new class of cross-bridged cyclam-based macrocycles featuring phosphonate pendant groups has been developed. 1,4,8,11-tetraazacyclotetradecane-1,8-di(methanephosphonic acid) (CB-TE2P, 1) and 1,4,8,11-tetraazacyclotetradecane-1-(methanephosphonic acid)-8-(methanecarboxylic acid) (CB-TE1A1P, 2) have been synthesized and have been shown to readily form neutral copper (II) complexes at room temperature as the corresponding dianions. Both complexes showed high kinetic inertness to demetallation and crystal structures confirmed complete encapsulation of copper (II) ion within each macrocycle’s cleft-like structure. Unprecedented for cross-bridged cyclam derivatives, both CB-TE2P (1) and CB-TE1A1P (2) can be radiolabeled with 64Cu at room temperature in less than 1 hour with specific activities >1mCi/μg. The in vivo behavior of both 64Cu-CB-TE2P and 64Cu-CB-TE1A1P were investigated through biodistribution studies using healthy, male, Lewis rats. Both new compounds showed rapid clearance with similar or lower accumulation in non-target organs/tissues when compared to other copper chelators including CB-TE2A, NOTA and Diamsar. PMID:22170043

  17. Evaluation of Novel 64Cu-Labeled Theranostic Gadolinium-Based Nanoprobes in HepG2 Tumor-Bearing Nude Mice

    NASA Astrophysics Data System (ADS)

    Hu, Pengcheng; Cheng, Dengfeng; Huang, Tao; Banizs, Anna B.; Xiao, Jie; Liu, Guobing; Chen, Quan; Wang, Yuenan; He, Jiang; Shi, Hongcheng

    2017-09-01

    Radiation therapy of liver cancer is limited by low tolerance of the liver to radiation. Radiosensitizers can effectively reduce the required radiation dose. AGuIX nanoparticles are small, multifunctional gadolinium-based nanoparticles that can carry radioisotopes or fluorescent markers for single-photon emission computed tomography (SPECT), positron emission tomography (PET), fluorescence imaging, and even multimodality imaging. In addition, due to the high atomic number of gadolinium, it can also serve as a tumor radiation sensitizer. It is critical to define the biodistribution and pharmacokinetics of these gadolinium-based nanoparticles to quantitate the magnitude and duration of their retention within the tumor microenvironment during radiotherapy. Therefore, in this study, we successfully labeled AGuIX with 64Cu through the convenient built-in chelator. The biodistribution studies indicated that the radiotracer 64Cu-AGuIX accumulates to high levels in the HepG2 xenograft of nude mice, suggesting that it would be a potential theranostic nanoprobe for image-guided radiotherapy in HCC. We also used a transmission electron microscope to confirm AGuIX uptake in the HepG2 cells. In radiation therapy studies, a decrease in 18F-FDG uptake was observed in the xenografts of the nude mice irradiated with AGuIX, which was injected 1 h before. These results provide proof-of-concept that AGuIX can be used as a theranostic radiosensitizer for PET imaging to guide radiotherapy for liver cancer.

  18. Imaging Cancer Using PET – the Effect of the Bifunctional Chelator on the Biodistribution of a 64Cu-Labeled Antibody

    PubMed Central

    Dearling, Jason L.J.; Voss, Stephan D.; Dunning, Patricia; Snay, Erin; Fahey, Frederic; Smith, Suzanne V.; Huston, James S.; Meares, Claude F.; Treves, S. Ted; Packard, Alan B.

    2010-01-01

    Introduction Use of copper radioisotopes in antibody radiolabeling is challenged by reported loss of the radionuclide from the bifunctional chelator used to label the protein. The objective of this study was to investigate the relationship between the thermodynamic stability of the 64Cu-complexes of five commonly used bifunctional chelators (BFCs) and the biodistribution of an antibody labeled with 64Cu using these chelators in tumor-bearing mice. Methods The chelators (p-NH2-Bn-NOTA, BAT-6, p-NH2-Bn-DOTA, DOTA, and SarAr) were conjugated to the anti-GD2 antibody ch14.18, and the conjugated antibody was labeled with 64Cu and injected into mice bearing subcutaneous human melanoma tumors (M21) (n = 3-5 for each study). Biodistribution data were obtained from PET images acquired at 1, 24 and 48 hours post-injection, and at 48 hours post-injection a full ex vivo biodistribution study was carried out. Results The biodistribution, including tumor targeting, was similar for all the radioimmunoconjugates. At 48 h post-injection, the only statistically significant differences in radionuclide uptake (p < 0.05) were between blood, liver, spleen and kidney. For example, liver uptake of [64Cu]ch14.18-p-NH2-Bn-NOTA was 4.74 ± 0.77 per cent of the injected dose per gram of tissue (%ID/g), and for [64Cu]ch14.18-SarAr was 8.06 ± 0.77 %ID/g. Differences in tumor targeting correlated with variations in tumor size rather than which BFC was used. Conclusions The results of this study indicate that differences in the thermodynamic stability of these chelator-Cu(II) complexes were not associated with significant differences in uptake of the tracer by the tumor. However, there were significant differences in tracer concentration in other tissues, including those involved in clearance of the radioimmunoconjugate (e.g., liver and spleen). PMID:21220127

  19. HaloTag as a reporter gene: positron emission tomography imaging with 64Cu-labeled second generation HaloTag ligands

    PubMed Central

    Hong, Hao; Benink, Hélène A; Uyeda, H Tetsuo; Valdovinos, Hector F; Zhang, Yin; Meisenheimer, Poncho; Barnhart, Todd E; Fan, Frank; Cai, Weibo

    2013-01-01

    The goal of this study is to employ the HaloTag technology for positron emission tomography (PET), which involves two components: the HaloTag protein (a modified hydrolase which covalently binds to synthetic ligands) and HaloTag ligands (HTLs). 4T1 murine breast cancer cells were stably transfected to express HaloTag protein on the surface (termed as 4T1-HaloTag-ECS, ECS denotes extracellular surface). Two new HTLs were synthesized and termed NOTA-HTL2G-S and NOTA-HTL2G-L (2G indicates second generation, S stands for short, L stands for long, NOTA denotes 1,4,7-triazacyclononane-N,N’N’’-triacetic acid). Microscopy studies confirmed surface expression of HaloTag in 4T1-HaloTag-ECS cells, which specifically bind NOTA-HTL2G-S/L. Uptake of 64Cu-NOTA-HTL2G-L in 4T1-HaloTag-ECS tumors (4.3 ± 0.5, 4.1± 0.2, 4.0 ± 0.2, 2.3 ± 0.1, and 2.2 ± 0.1 %ID/g at 0.5, 3, 6, 18, and 24 h post-injection respectively; n = 4) was significantly higher than that in the 4T1 tumors (3.0 ± 0.3, 3.0± 0.1, 3.0 ± 0.2, 2.0 ± 0.4, and 2.4 ± 0.3 %ID/g at 0.5, 3, 6, 18, and 24 h post-injection respectively; n = 4) at early time points. In comparison, 64Cu-NOTA-HTL2G-S did not demonstrate significant uptake in either 4T1-HaloTag-ECS or 4T1 tumors. Blocking studies and autoradiography of tumor lysates confirmed that 64Cu-NOTA-HTL2G-L binds specifically to HaloTag protein in the 4T1-HaloTag-ECS tumors, corroborated by histology. HaloTag protein-specific targeting and PET imaging in vivo with 64Cu-NOTA-HTL2G-L serves as a proof-of-principle for future non-invasive and sensitive tracking of HaloTag-transfected cells with PET, as well as many other studies of gene/protein/cell function in vivo. PMID:23634240

  20. Evaluation of Novel (64)Cu-Labeled Theranostic Gadolinium-Based Nanoprobes in HepG2 Tumor-Bearing Nude Mice.

    PubMed

    Hu, Pengcheng; Cheng, Dengfeng; Huang, Tao; Banizs, Anna B; Xiao, Jie; Liu, Guobing; Chen, Quan; Wang, Yuenan; He, Jiang; Shi, Hongcheng

    2017-09-06

    Radiation therapy of liver cancer is limited by low tolerance of the liver to radiation. Radiosensitizers can effectively reduce the required radiation dose. AGuIX nanoparticles are small, multifunctional gadolinium-based nanoparticles that can carry radioisotopes or fluorescent markers for single-photon emission computed tomography (SPECT), positron emission tomography (PET), fluorescence imaging, and even multimodality imaging. In addition, due to the high atomic number of gadolinium, it can also serve as a tumor radiation sensitizer. It is critical to define the biodistribution and pharmacokinetics of these gadolinium-based nanoparticles to quantitate the magnitude and duration of their retention within the tumor microenvironment during radiotherapy. Therefore, in this study, we successfully labeled AGuIX with (64)Cu through the convenient built-in chelator. The biodistribution studies indicated that the radiotracer (64)Cu-AGuIX accumulates to high levels in the HepG2 xenograft of nude mice, suggesting that it would be a potential theranostic nanoprobe for image-guided radiotherapy in HCC. We also used a transmission electron microscope to confirm AGuIX uptake in the HepG2 cells. In radiation therapy studies, a decrease in (18)F-FDG uptake was observed in the xenografts of the nude mice irradiated with AGuIX, which was injected 1 h before. These results provide proof-of-concept that AGuIX can be used as a theranostic radiosensitizer for PET imaging to guide radiotherapy for liver cancer.

  1. A comparison of image contrast with (64)Cu-labeled long circulating liposomes and (18)F-FDG in a murine model of mammary carcinoma.

    PubMed

    Wong, Andrew W; Ormsby, Eleanor; Zhang, Hua; Seo, Jai Woong; Mahakian, Lisa M; Caskey, Charles F; Ferrara, Katherine W

    2013-01-01

    Conjugation of the (64)Cu PET radioisotope (t(1/2) = 12.7 hours) to long circulating liposomes enables long term liposome tracking. To evaluate the potential clinical utility of this radiotracer in diagnosis and therapeutic guidance, we compare image contrast, tumor volume, and biodistribution of (64)Cu-liposomes to metrics obtained with the dominant clinical tracer, (18)F-FDG. Twenty four female FVB mice with MET1 mammary carcinoma tumor grafts were examined. First, serial PET images were obtained with the (18)F-FDG radiotracer at 0.5 hours after injection and with the (64)Cu-liposome radiotracer at 6, 18, 24, and 48 hours after injection (n = 8). Next, paired imaging and histology were obtained at four time points: 0.5 hours after (18)F-FDG injection and 6, 24, and 48 hours after (64)Cu-liposome injection (n = 16). Tissue biodistribution was assessed with gamma counting following necropsy and tumors were paraffin embedded, sectioned, and stained with hematoxylin and eosin. The contrast ratio of images obtained using (18)F-FDG was 0.88 ± 0.01 (0.5 hours after injection), whereas with the (64)Cu-liposome radiotracer the contrast ratio was 0.78 ± 0.01, 0.89 ± 0.01, 0.88 ± 0.01, and 0.94 ± 0.01 at 6, 18, 24, and 48 hours, respectively. Estimates of tumor diameter were comparable between (64)Cu-liposomes and (18)F-FDG, (64)Cu-liposomes and necropsy, and (64)Cu-liposomes and ultrasound with Pearson's r-squared values of 0.79, 0.79, and 0.80, respectively. Heterogeneity of tumor tracer uptake was observed with both tracers, correlating with regions of necrosis on histology. The average tumor volume of 0.41 ± 0.05 cc measured with (64)Cu-liposomes was larger than that estimated with (18)F-FDG (0.28 ± 0.04 cc), with this difference apparently resulting primarily from accumulation of the radiolabeled particles in the pro-angiogenic tumor rim. The imaging of radiolabeled nanoparticles can facilitate tumor detection, identification of tumor margins, therapeutic evaluation and interventional guidance.

  2. Synthesis, Cu(II) complexation, 64Cu-labeling and biological evaluation of cross-bridged cyclam chelators with phosphonate pendant arms.

    PubMed

    Ferdani, Riccardo; Stigers, Dannon J; Fiamengo, Ashley L; Wei, Lihui; Li, Barbara T Y; Golen, James A; Rheingold, Arnold L; Weisman, Gary R; Wong, Edward H; Anderson, Carolyn J

    2012-02-21

    A new class of cross-bridged cyclam-based macrocycles featuring phosphonate pendant groups has been developed. 1,4,8,11-tetraazacyclotetradecane-1,8-di(methanephosphonic acid) (CB-TE2P, 1) and 1,4,8,11-tetraazacyclotetradecane-1-(methanephosphonic acid)-8-(methanecarboxylic acid) (CB-TE1A1P, 2) have been synthesized and have been shown to readily form neutral copper(II) complexes at room temperature as the corresponding dianions. Both complexes showed high kinetic inertness to demetallation and crystal structures confirmed complete encapsulation of copper(II) ion within each macrocycle's cleft-like structure. Unprecedented for cross-bridged cyclam derivatives, both CB-TE2P (1) and CB-TE1A1P (2) can be radiolabeled with (64)Cu at room temperature in less than 1 h with specific activities >1 mCi μg(-1). The in vivo behavior of both (64)Cu-CB-TE2P and (64)Cu-CB-TE1A1P were investigated through biodistribution studies using healthy male Lewis rats. Both new compounds showed rapid clearance with similar or lower accumulation in non-target organs/tissues when compared to other copper chelators including CB-TE2A, NOTA and Diamsar.

  3. Targeted radiotherapy with [(90)Y]-SMT 487 in mice bearing human nonsmall cell lung tumor xenografts induced to express human somatostatin receptor subtype 2 with an adenoviral vector.

    PubMed

    Rogers, Buck E; Zinn, Kurt R; Lin, Chin-Yu; Chaudhuri, Tandra R; Buchsbaum, Donald J

    2002-02-15

    Novel approaches to increasing the therapeutic efficacy of targeted radiotherapy of cancer are required. One strategy to achieve this goal is to induce high-level expression of a receptor on the surface of tumor cells that can be targeted with a radiolabeled peptide. The objectives of this study were to 1) induce somatostatin receptor (SSTr2) expression in tumor cells using an adenovirus encoding the SSTr2 gene (AdSSTr2), 2) demonstrate tumor localization of [(111)In]-DTPA-D-Phe(1)-octreotide in AdSSTr2-injected tumors, and 3) show therapeutic efficacy with [(90)Y]-DOTA-D-Phe(1)-Tyr(3)-octreotide ([(90)Y]-SMT 487). SSTr2 expression was validated in vitro by the binding and subsequent internalization of [(111)In]-DTPA-D-Phe(1)-octreotide (21.3% per mg of total protein) in A-427 cells infected with AdSSTr2. In vivo imaging confirmed 5- to 10-fold greater uptake 5.5 hours after intravenous administration of [(111)In]-DTPA-D-Phe(1)-octreotide in AdSSTr2-injected tumors relative to control tumors. For therapy studies, mice bearing established subcutaneous A-427 tumors were given two intratumoral injections of AdSSTr2 1 week apart, followed by an intravenous injection of 400 microCi or 500 microCi [(90)Y]-SMT 487 at 2 and 4 days after each adenoviral administration. Control animals either were not treated or were administered 500 microCi [(90)Y]-SMT 487 with no AdSSTr2 injection. These studies showed that untreated animals and animals treated with no virus and 500 microCi [(90)Y]-SMT 487 had median tumor quadrupling times of 16 and 25 days, respectively. Mice administered AdSSTr2 and either 400 microCi or 500 microCi of [(90)Y]-SMT 487 demonstrated significantly longer median tumor quadrupling times of 40 and 44 days, respectively (P < 0.02). These studies are the first to demonstrate in vivo therapeutic efficacy using a radiolabeled peptide targeted to a receptor expressed on the surface of tumor cells following gene transfer. Future studies will focus on the

  4. Processing of generator-produced 68Ga for medical application.

    PubMed

    Zhernosekov, Konstantin P; Filosofov, Dimitry V; Baum, Richard P; Aschoff, Peter; Bihl, Heiner; Razbash, Anatoli A; Jahn, Markus; Jennewein, Mark; Rösch, Frank

    2007-10-01

    The (68)Ge/(68)Ga generator provides an excellent source of positron-emitting (68)Ga. However, newly available "ionic" (68)Ge/(68)Ga radionuclide generators are not necessarily optimized for the synthesis of (68)Ga-labeled radiopharmaceuticals. The eluates have rather large volumes, a high concentration of H(+) (pH of 1), a breakthrough of (68)Ge, increasing with time or frequency of use, and impurities such as stable Zn(II) generated by the decay of (68)Ga, Ti(IV) as a constituent of the column material, and Fe(III) as a general impurity. We have developed an efficient route for the processing of generator-derived (68)Ga eluates, including the labeling and purification of biomolecules. Preconcentration and purification of the initial generator eluate are performed using a miniaturized column with organic cation-exchanger resin and hydrochloric acid/acetone eluent. The purified fraction was used for the labeling of nanomolar amounts of octreotide derivatives either in pure aqueous solution or in buffers. Using the generator post-eluate processing system, >97% of the initially eluated (68)Ga activity was obtained within 4 min as a 0.4-mL volume of a hydrochloric acid/acetone fraction. The initial amount of (68)Ge(IV) was decreased by a factor of 10(4), whereas initial amounts of Zn(II), Ti(IV), and Fe(III) were reduced by factors of 10(5), 10(2), and 10, respectively. The processed (68)Ga fraction was directly transferred to solutions containing labeling precursors-for example, DOTA-dPhe(1)-Tyr(3)-octreotide (DOTATOC) (DOTA = 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid). Labeling yields of >95% were achieved within 10 min. Overall yields reached 70% at 20 min after generator elution relative to the eluted (68)Ga activity, not corrected for decay. Specific activities of (68)Ga-DOTATOC were 50 MBq/nmol using a standard protocol, reaching 450 MBq/nmol under optimized conditions. Processing on a cation-exchanger in hydrochloric acid/acetone media

  5. 64Cu-labeled somatostatin analogues conjugated with cross-bridged phosphonate-based chelators via strain-promoted click chemistry for PET imaging: in silico through in vivo studies.

    PubMed

    Cai, Zhengxin; Ouyang, Qin; Zeng, Dexing; Nguyen, Kim N; Modi, Jalpa; Wang, Lirong; White, Alexander G; Rogers, Buck E; Xie, Xiang-Qun; Anderson, Carolyn J

    2014-07-24

    Somatostatin receptor subtype 2 (sstr2) is a G-protein-coupled receptor (GPCR) that is overexpressed in neuroendocrine tumors. The homology model of sstr2 was built and was used to aid the design of new somatostatin analogues modified with phosphonate-containing cross-bridged chelators for evaluation of using them as PET imaging radiopharmaceuticals. The new generation chelators were conjugated to Tyr3-octreotate (Y3-TATE) through bioorthogonal, strain-promoted alkyne azide cycloaddition (SPAAC) to form CB-TE1A1P-DBCO-Y3-TATE (AP) and CB-TE1K1P-PEG4-DBCO-Y3-TATE (KP) in improved yields compared to standard direct conjugation methods of amide bond formation. Consistent with docking studies, the clicked bioconjugates showed high binding affinities to sstr2, with Kd values ranging from 0.6 to 2.3 nM. Selected isomers of the clicked products were used in biodistribution and PET/CT imaging. Introduction of the bulky dibenzocyclooctyne group in AP decreased clearance rates from circulation. However, the additional carboxylate group and PEG linker from the KP conjugate significantly improved labeling conditions and in vivo stability of the copper complex and ameliorated the slower pharmacokinetics of the clicked somatostatin analogues.

  6. 64Cu-Labeled Somatostatin Analogues Conjugated with Cross-Bridged Phosphonate-Based Chelators via Strain-Promoted Click Chemistry for PET Imaging: In silico through in Vivo Studies

    PubMed Central

    2015-01-01

    Somatostatin receptor subtype 2 (sstr2) is a G-protein-coupled receptor (GPCR) that is overexpressed in neuroendocrine tumors. The homology model of sstr2 was built and was used to aid the design of new somatostatin analogues modified with phosphonate-containing cross-bridged chelators for evaluation of using them as PET imaging radiopharmaceuticals. The new generation chelators were conjugated to Tyr3-octreotate (Y3-TATE) through bioorthogonal, strain-promoted alkyne azide cycloaddition (SPAAC) to form CB-TE1A1P–DBCO–Y3-TATE (AP) and CB-TE1K1P–PEG4–DBCO–Y3-TATE (KP) in improved yields compared to standard direct conjugation methods of amide bond formation. Consistent with docking studies, the clicked bioconjugates showed high binding affinities to sstr2, with Kd values ranging from 0.6 to 2.3 nM. Selected isomers of the clicked products were used in biodistribution and PET/CT imaging. Introduction of the bulky dibenzocyclooctyne group in AP decreased clearance rates from circulation. However, the additional carboxylate group and PEG linker from the KP conjugate significantly improved labeling conditions and in vivo stability of the copper complex and ameliorated the slower pharmacokinetics of the clicked somatostatin analogues. PMID:24983404

  7. Cu(I)-assisted click chemistry strategy for conjugation of non-protected cross-bridged macrocyclic chelators to tumour-targeting peptides.

    PubMed

    Cai, Zhengxin; Li, Barbara T Y; Wong, Edward H; Weisman, Gary R; Anderson, Carolyn J

    2015-03-07

    Copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) click chemistry has inherent challenges for copper-labeled radiopharmaceuticals. An azide-modified phosphonate-based cross-bridged macrocyclic chelator was synthesized for click chemistry conjugation with azide-modified Y3-TATE (a somatostatin analogue) on resin, without the need for protecting the chelator. The (64)Cu-labeled bioconjugate shows favourable in vitro and in vivo behaviour.

  8. VEGF-Iron Oxide Conjugate for Dual MR and PET Imaging of Breast Cancer Angiogenesis

    DTIC Science & Technology

    2007-09-01

    iron oxide nanoparticles conjugated with macrocyclic chelating agent DOTA for 64Cu-labeling and cyclic RGD peptide for integrin alpha (v)beta(3...Nanoparticles We have developed two types of novel superparamagentic iron oxide nanoparticles (USPIO), namely, PVP -IO and PASP-IO...Polyvinylpyrrolidone ( PVP )-coated iron oxide ( PVP -IO) nanoparticles were synthesized by a one-step thermal decomposition method (Fig. 3). The overall size of the

  9. Click-chemistry strategy for labeling antibodies with copper-64 via a cross-bridged tetraazamacrocyclic chelator scaffold.

    PubMed

    Kumar, Amit; Hao, Guiyang; Liu, Li; Ramezani, Saleh; Hsieh, Jer-Tsong; Öz, Orhan K; Sun, Xiankai

    2015-04-15

    We report a click-chemistry based modular strategy for antibody labeling with (64)Cu (t1/2 = 12.7 h; β(+) 0.656 MeV, 17.4%; β(-) 0.573 MeV, 39%; EC 43%) under ambient condition utilizing a cross-bridged tetraazamacrocyclic (CB-TE2A) analogue, which otherwise requires harsh conditions that make the CB-TE2A analogues under-utilized for protein labeling despite the fact that they form kinetically inert copper complexes with high in vivo stability. Our strategy involves prelabeling a CB-TE2A based scaffold (CB-TE2A-1C) with (64)Cu and its subsequent reaction with an antibody via the tetrazine-norbornene mediated click chemistry. The effectiveness of this strategy was demonstrated by labeling two monoclonal antibodies, an anti-PSMA antibody (YPSMA-1) and a chimeric anti-phosphatidylserine antibody (Bavituximab). The immunoreactivity of the antibodies remained unchanged after the tetrazine modification and click-chemistry (64)Cu labeling. To further demonstrate the practicality of the modular (64)Cu labeling strategy, we tested positron emission tomography (PET) imaging of tumor with the (64)Cu-labeled bavituximab in a mouse xenograft model. The tumor visualization and uptake of the labeled antibody exhibited the versatility of the click-chemistry strategy.

  10. Monoclonal antibodies for copper-64 PET dosimetry and radioimmunotherapy.

    PubMed

    Bryan, Jeffrey N; Jia, Fang; Mohsin, Huma; Sivaguru, Geethapriya; Anderson, Carolyn J; Miller, William H; Henry, Carolyn J; Lewis, Michael R

    2011-06-15

    We previously described a two-antibody model of (64)Cu radioimmunotherapy to evaluate low-dose, solid-tumor response. This model was designed to test the hypothesis that cellular internalization is critical in causing tumor cell death by mechanisms in addition to radiation damage. The purpose of the present study was to estimate radiation dosimetry for both antibodies (mAbs) using positron emission tomography (PET) imaging, and evaluate the effect of internalization on tumor growth. Dosimetry was similar between therapy groups. Median time to tumor progression to 1 g ranged from 7 to 12 days for control groups and was 32 days for both treatment groups (p < 0.0001). No statistically significant difference existed between any control group or between the treatment groups. In female nude mice bearing LS174T colon carcinoma xenografts, tumor dosimetry was calculated using serial PET images of three mice in each group of either internalizing (64)Cu-labeled DOTA-cBR96 (DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) or non-internalizing (64)Cu-labeled DOTA-cT84.66 from 3 to 48 h. For the therapy study, controls (n = 10) received saline, DOTA-cBR96, or DOTA-cT84.66. Treatment animals (n = 9) received 0.890 mCi of (64)Cu-labeled DOTA-cBR96 or 0.710 mCi of (64)Cu-labeled DOTA-cT84.66. Tumors were measured daily. PET imaging allows the use of (64)Cu for pre-therapy calculation of tumor dosimetry. In spite of highly similar tumor dosimetry, an internalizing antibody did not improve the outcome of (64)Cu radioimmunotherapy. Radioresistance of this tumor cell line and copper efflux may have confounded the study. Further investigations of the 2 therapeutic efficacy of (64)Cu-labeled mAbs will focus on interaction between (64)Cu and tumor suppressor genes and copper chaperones.

  11. Tumor Uptake of Hollow Gold Nanospheres after Intravenous and Intra-arterial Injection: PET/CT Study in a Rabbit VX2 Liver Cancer Model

    PubMed Central

    Tian, Mei; Lu, Wei; Zhang, Rui; Xiong, Chiyi; Ensor, Joe; Nazario, Javier; Jackson, James; Shaw, Colette; Dixon, Katherine A.; Miller, Jennifer; Wright, Kenneth; Li, Chun; Gupta, Sanjay

    2014-01-01

    Purpose This study was designed to investigate the intratumoral uptake of hollow gold nanospheres (HAuNS) after hepatic intra-arterial (IA) and intravenous (IV) injection in a liver tumor model. Materials and Methods Fifteen VX2 tumor-bearing rabbits were randomized into five groups (N=3 in each group) that received either IV 64Cu-labeled PEG-HAuNS (IV-PEG-HAuNS), IA 64Cu-labeled PEG-HAuNS (IA-PEG-HAuNS), IV cyclic peptide (RGD)-conjugated 64Cu-labeled PEG-HAuNS (IV-RGD-PEG-HAuNS), IA RGD-conjugated 64Cu-labeled PEG-HAuNS (IA-RGD-PEG-HAuNS), or IA 64Cu-labeled PEG-HAuNS with lipiodol (IA-PEG-HAuNS-lipiodol). The animals underwent PET/CT 1 hour after injection, and uptake expressed as percentage of injected dose per gram of tissue (%ID/g) was measured in tumor and major organs. The animals were euthanized 24 hours after injection, and tissues were evaluated for radioactivity. Results At 1 hour after injection, animals in the IA-PEG-HAuNS-lipiodol group showed significantly higher tumor uptake (P < 0.001) and higher ratios of tumor-to-normal liver uptake (P < 0.001) than those in all other groups. The biodistribution of radioactivity 24 hours after injection showed that IA delivery of PEG-HAuNS with lipiodol resulted in the highest tumor uptake (0.33 %ID/g; P < 0.001) and tumor-to-normal liver ratio (P < 0.001) among all delivery methods. At 24 hours, the IA-RGD-PEG-HAuNS group showed higher tumor uptake than the IA-PEG-HAuNS group (0.20 %ID/g vs. 0.099 %ID/g; P < 0.001). Conclusion Adding iodized oil to IA-PEG-HAuNS maximizes nanoparticle delivery to hepatic tumors and therefore may be useful in targeted chemotherapy and photoablative therapy. PET/CT can be used to noninvasively monitor the biodistribution of radiolabeled HAuNS after IV or IA injection. PMID:23608932

  12. PET Imaging in Prostate Cancer: Focus on Prostate-Specific Membrane Antigen

    PubMed Central

    Mease, Ronnie C.; Foss, Catherine A.; Pomper, Martin G.

    2014-01-01

    Prostate cancer (PCa) is the second leading cause of cancer-related death in American men. Positron emission tomography/computed tomography (PET/CT) with emerging radiopharmaceuticals promises accurate staging of primary disease, restaging of recurrent disease, detection of metastatic lesions and, ultimately, for predicting the aggressiveness of disease. Prostate-specific membrane antigen (PSMA) is a well-characterized imaging biomarker of PCa. Because PSMA levels are directly related to androgen independence, metastasis and progression, PSMA could prove an important target for the development of new radiopharmaceuticals for PET. Preclinical data for new PSMA-based radiotracers are discussed and include new 89Zr- and 64Cu-labeled anti-PSMA antibodies and antibody fragments, 64Cu-labeled aptamers, and 11C-, 18F-, 68Ga-, 64Cu-, and 86Y-labeled low molecular weight inhibitors of PSMA. Several of these agents, namely 68Ga-HBED-CC conjugate 15, 18F-DCFBC 8, and BAY1075553 are particularly promising, each having detected sites of PCa in initial clinical studies. These early clinical results suggest that PET/CT using PSMA-targeted agents, especially with compounds of low molecular weight, will make valuable contributions to the management of PCa. PMID:23590171

  13. Theranostic Unimolecular Micelles Based on Brush-Shaped Amphiphilic Block Copolymers for Tumor-Targeted Drug Delivery and Positron Emission Tomography Imaging

    PubMed Central

    2015-01-01

    Brush-shaped amphiphilic block copolymers were conjugated with a monoclonal antibody against CD105 (i.e., TRC105) and a macrocyclic chelator for 64Cu-labeling to generate multifunctional theranostic unimolecular micelles. The backbone of the brush-shaped amphiphilic block copolymer was poly(2-hydroxyethyl methacrylate) (PHEMA) and the side chains were poly(l-lactide)-poly(ethylene glycol) (PLLA-PEG). The doxorubicin (DOX)-loaded unimolecular micelles showed a pH-dependent drug release profile and a uniform size distribution. A significantly higher cellular uptake of TRC105-conjugated micelles was observed in CD105-positive human umbilical vein endothelial cells (HUVEC) than nontargeted micelles due to CD105-mediated endocytosis. In contrast, similar and extremely low cellular uptake of both targeted and nontargeted micelles was observed in MCF-7 human breast cancer cells (CD105-negative). The difference between the in vivo tumor accumulation of 64Cu-labeled TRC105-conjugated micelles and that of nontargeted micelles was studied in 4T1 murine breast tumor-bearing mice, by serial positron emission tomography (PET) imaging and validated by biodistribution studies. These multifunctional unimolecular micelles offer pH-responsive drug release, noninvasive PET imaging capability, together with both passive and active tumor-targeting abilities, thus making them a desirable nanoplatform for cancer theranostics. PMID:24628452

  14. Visualizing implanted tumors in mice with magnetic resonance imaging using magnetotactic bacteria.

    PubMed

    Benoit, Michael R; Mayer, Dirk; Barak, Yoram; Chen, Ian Y; Hu, Wei; Cheng, Zhen; Wang, Shan X; Spielman, Daniel M; Gambhir, Sanjiv S; Matin, A

    2009-08-15

    To determine if magnetotactic bacteria can target tumors in mice and provide positive contrast for visualization using magnetic resonance imaging. The ability of the magnetotactic bacterium, Magnetospirillum magneticum AMB-1 (referred to from here as AMB-1), to confer positive magnetic resonance imaging contrast was determined in vitro and in vivo. For the latter studies, AMB-1 were injected either i.t. or i.v. Bacterial growth conditions were manipulated to produce small (approximately 25-nm diameter) magnetite particles, which were observed using transmission electron microscopy. Tumor targeting was confirmed using 64Cu-labeled bacteria and positron emission tomography and by determination of viable cell counts recovered from different organs and the tumor. We show that AMB-1 bacteria with small magnetite particles generate T1-weighted positive contrast, enhancing in vivo visualization by magnetic resonance imaging. Following i.v. injection of 64Cu-labeled AMB-1, positron emission tomography imaging revealed increasing colonization of tumors and decreasing infection of organs after 4 hours. Viable cell counts showed that, by day 6, the bacteria had colonized tumors but were cleared completely from other organs. Magnetic resonance imaging showed a 1.22-fold (P = 0.003) increased positive contrast in tumors on day 2 and a 1.39-fold increase (P = 0.0007) on day 6. Magnetotactic bacteria can produce positive magnetic resonance imaging contrast and colonize mouse tumor xenografts, providing a potential tool for improved magnetic resonance imaging visualization in preclinical and translational studies to track cancer.

  15. Generation and Screening of Monoclonal Antibodies for ImmunoPET Imaging of IGF1R in Prostate Cancer

    PubMed Central

    2015-01-01

    Insulin-like growth factor 1 receptor (IGF1R) plays an important role in proliferation, apoptosis, angiogenesis, and tumor invasion. The expression level of IGF1R is related to resistance to several targeted therapies. The goal of this study was to develop an immunoPET tracer for imaging of IGF1R in prostate cancer. Murine antibodies against human IGF1R were generated in BALB/c mice, which were screened in IGF1R-positive MCF-7 cells using flow cytometry as well as biodistribution studies with multiple 64Cu-labeled antibody clones. The antibody production method we adopted could readily produce milligram quantities of anti-IGF1R antibodies for in vivo studies. One antibody clone (1A2G11) with the highest affinity for IGF1R was selected and conjugated to NOTA for 64Cu-labeling. NOTA-1A2G11 maintained IGF1R specificity/avidity based on flow cytometry. 64Cu-labeling was achieved with good yield (>50%) and high specific activity (>1 Ci/μmol). Serial PET imaging revealed that uptake of 64Cu-NOTA-1A2G11 was 2.8 ± 0.7, 10.2 ± 2.6, and 9.6 ± 1.7 %ID/g in IGF1R-positive DU-145 tumors at 4, 24, and 48 h postinjection, respectively (n = 3), significantly higher than that in IGF1R-negative LNCaP tumors (<3 %ID/g at each time point) except at 4 h postinjection. Histology studies showed strong correlations between IGF1R expression level in the prostate cancer tumor tissues and tumor uptake of 64Cu-NOTA-1A2G11. Prominent, persistent, and IGF1R-specific uptake of 64Cu-NOTA-1A2G11 in IGF1R-positive prostate tumors holds strong potential for future cancer diagnosis, prognosis, and therapy using this antibody. PMID:25157758

  16. Initial comparison of Cu-67-and Cu-64-labeled anti-colorectal carcinoma Mab 1A3 as agents for radioimmunotherapy in tumor-bearing hamsters

    SciTech Connect

    Anderson, C.J.; Connett, J.M.; Guo, L.W.

    1994-05-01

    For imaging or radiotherapy, {sup 64}Cu (T{sub 1/2}=12.8 h) has advantages over {sup 67}Cu (T{sub 1/2}=62h) that include wider availibility, lower cost, and a higher specific activity. {sup 67}Cu- and {sup 64}Cu- labeled monoclonal antibody (MAb) 1A3 showed similar lethal efficiencies in vitro to LS174T human colon cancer cells. To compare the lethal effiencies of these agents in vivo, 200 or 400 {mu}Ci of {sup 67}Cu-labeled Mab 1A3 and 500, 1000 or 2000 {mu}Ci of {sup 64}Cu-labeled 1A3 were administered into hamsters carrying 2 day old GW-39 human colon tumors in their thigh musculature. In another group of hamsters, {sup 67}Cu- and {sup 64}Cu-labeled non-specific Mab MOPC were also administered in corresponding amounts. A control group was injected with saline solution. At all doses, hamsters that were given either {sup 64}Cu- or {sup 67}Cu-labeled 1A3 showed inhibition of tumor growth over hamsters injected with either saline or {sup 64}Cu- or {sup 67}Cu-labeled MOPC. Tumor weights in hamsters administered with 2000 {mu}Ci of {sup 64}Cu-1A3 showed an 11-fold decrease over tumors in hamsters given saline (0.184 {plus_minus} 0.106 (n=3) vs 2.056 {plus_minus} 0.369 (n=10)), and a 5-fold decrease over those where {sup 64}Cu-MOPC was administered (0.184 {plus_minus} 0.106 (n=3) vs 0.961 {plus_minus} 0.228 (n=4)). In hamsters injected with 400 {mu}Ci {sup 67}Cu-1A3, a 13-fold decrease in tumor weight was observed over control hamsters given saline (0.345 {plus_minus} 0.129 (n=5)vs 4.457 {plus_minus}0.405 (n=10)), and a 7-fold decrease was observed when {sup 67}Cu-MOPC was injected (0.345 {plus_minus} 0.129 (n=5) vs 2.507 {plus_minus} 1.064 (n=5)). Given the 5-fold difference in half-life between {sup 67}Cu and {sup 64}Cu, at corresponding doses the inhibition of tumor growth was similar. These initial experiments indicate that {sup 64}Cu has a radiotherapeutic potential comparable to {sup 67}Cu when labeled to Mab 1A3.

  17. Copper-64 Radiopharmaceuticals for PET Imaging of Cancer: Advances in Preclinical and Clinical Research

    PubMed Central

    Ferdani, Riccardo

    2009-01-01

    Summation Copper-64 (T1/2 = 12.7 hours; β+, 0.653 MeV [17.8 %]; β−, 0.579 MeV [38.4 %]) has decay characteristics that allow for positron emission tomography (PET) imaging and targeted radiotherapy of cancer. The well-established coordination chemistry of copper allows for its reaction with a wide variety of chelator systems that can potentially be linked to peptides and other biologically relevant small molecules, antibodies, proteins, and nanoparticles. The 12.7-hours half-life of 64Cu provides the flexibility to image both smaller molecules and larger, slower clearing proteins and nanoparticles. In a practical sense, the radionuclide or the 64Cu-radiopharmaceuticals can be easily shipped for PET imaging studies at sites remote to the production facility. Due to the versatility of 64Cu, there has been an abundance of novel research in this area over the past 20 years, primarily in the area of PET imaging, but also for the targeted radiotherapy of cancer. The biologic activity of the hypoxia imaging agent, 60/64Cu-ATSM, has been described in great detail in animal models and in clinical PET studies. An investigational new drug application for 64Cu-ATSM was recently approved by the U.S. Food and Drug Administration (FDA) in the United States, paving the way for a multicenter trial to validate the utility of this agent, with the hopeful result being FDA approval for routine clinical use. This article discusses state-of-the-art cancer imaging with 64Cu radiopharmaceuticals, including 64Cu-ATSM for imaging hypoxia, 64Cu-labeled peptides for tumor-receptor targeting, 64Cu-labeled monoclonal antibodies for targeting tumor antigens, and 64Cu-labeled nanoparticles for cancer targeting. The emphasis of this article will be on the new scientific discoveries involving 64Cu radiopharmaceuticals, as well as the translation of these into human studies. PMID:19694573

  18. RGD-based PET tracers for imaging receptor integrin αv β3 expression.

    PubMed

    Cai, Hancheng; Conti, Peter S

    2013-05-15

    Positron emission tomography (PET) imaging of receptor integrin αv β3 expression may play a key role in the early detection of cancer and cardiovascular diseases, monitoring disease progression, evaluating therapeutic response, and aiding anti-angiogenic drugs discovery and development. The last decade has seen the development of new PET tracers for in vivo imaging of integrin αv β3 expression along with advances in PET chemistry. In this review, we will focus on the radiochemistry development of PET tracers based on arginine-glycine-aspartic acid (RGD) peptide, present an overview of general strategies for preparing RGD-based PET tracers, and review the recent advances in preparations of (18) F-labeled, (64) Cu-labeled, and (68) Ga-labeled RGD tracers, RGD-based PET multivalent probes, and RGD-based PET multimodality probes for imaging receptor integrin αv β3 expression.

  19. Particle Size, Surface Coating, and PEGylation Influence the Biodistribution of Quantum Dots in Living Mice

    PubMed Central

    Schipper, Meike L.; Iyer, Gopal; Koh, Ai Leen; Cheng, Zhen; Ebenstein, Yuval; Aharoni, Assaf; Keren, Shay; Bentolila, Laurent A.; Li, Jianquing; Rao, Jianghong; Chen, Xiaoyuan; Banin, Uri; Wu, Anna M.; Sinclair, Robert; Weiss, Shimon

    2011-01-01

    This study evaluates the influence of particle size, PEGylation, and surface coating on the quantitative biodistribution of near-infrared-emitting quantum dots (QDs) in mice. Polymer- or peptide-coated 64Cu-labeled QDs 2 or 12 nm in diameter, with or without polyethylene glycol (PEG) of molecular weight 2000, are studied by serial micropositron emission tomography imaging and region-of-interest analysis, as well as transmission electron microscopy and inductively coupled plasma mass spectrometry. PEGylation and peptide coating slow QD uptake into the organs of the reticuloendothelial system (RES), liver and spleen, by a factor of 6–9 and 2–3, respectively. Small particles are in part renally excreted. Peptide-coated particles are cleared from liver faster than physical decay alone would suggest. Renal excretion of small QDs and slowing of RES clearance by PEGylation or peptide surface coating are encouraging steps toward the use of modified QDs for imaging living subjects. PMID:19051182

  20. Rapid Hepatobiliary Excretion of Micelle-Encapsulated/Radiolabeled Upconverting Nanoparticles as an Integrated Form

    PubMed Central

    Seo, Hyo Jung; Nam, Sang Hwan; Im, Hyung-Jun; Park, Ji-yong; Lee, Ji Youn; Yoo, Byeongjun; Lee, Yun-Sang; Jeong, Jae Min; Hyeon, Taeghwan; Who Kim, Ji; Lee, Jae Sung; Jang, In-Jin; Cho, Joo-Youn; Hwang, Do Won; Suh, Yung Doug; Lee, Dong Soo

    2015-01-01

    In the field of nanomedicine, long term accumulation of nanoparticles (NPs) in the mononuclear phagocyte system (MPS) such as liver is the major hurdle in clinical translation. On the other hand, NPs could be excreted via hepatobiliary excretion pathway without overt tissue toxicity. Therefore, it is critical to develop NPs that show favorable excretion property. Herein, we demonstrated that micelle encapsulated 64Cu-labeled upconverting nanoparticles (micelle encapsulated 64Cu-NOTA-UCNPs) showed substantial hepatobiliary excretion by in vivo positron emission tomography (PET) and also upconversion luminescence imaging (ULI). Ex vivo biodistribution study reinforced the imaging results by showing clearance of 84% of initial hepatic uptake in 72 hours. Hepatobiliary excretion of the UCNPs was also verified by transmission electron microscopy (TEM) examination. Micelle encapsulated 64Cu-NOTA-UCNPs could be an optimal bimodal imaging agent owing to quantifiability of 64Cu, ability of in vivo/ex vivo ULI and good hepatobiliary excretion property. PMID:26494465

  1. A Novel Side-Bridged Hybrid Phosphonate/Acetate Pendant Cyclam: Synthesis, Characterization, and 64Cu Small Animal PET Imaging

    PubMed Central

    Boswell, C. Andrew; Regino, Celeste A. S.; Baidoo, Kwamena E.; Wong, Karen J.; Milenic, Diane E.; Kelley, James A.; Lai, Christopher C.; Brechbiel, Martin W.

    2008-01-01

    Copper-64 (t½ = 12.7 hr; β+: 0.653 MeV, 17.4%; β−: 0.578 MeV, 39%) is produced in a biomedical cyclotron and has applications in both imaging and therapy. Macrocyclic chelators are widely used as bifunctional chelators to bind copper radionuclides to antibodies and peptides owing to their relatively high kinetic stability. A novel side-bridged cyclam featuring both pendant acetate and phosphonate groups was synthesized using a Kabachnik-Fields approach followed by hydrobromic acid deprotection. The Cu(II) complex of the novel ligand was synthesized, radiolabeling with 64Cu was demonstrated, and in vitro (serum) stability was performed. In addition, in vivo distribution and clearance of the 64Cu-labeled complex was visualized by positron emission tomography (PET) imaging. This novel chelate may be useful in 64Cu-mediated diagnostic positron emission tomography (PET) imaging as well as targeted radiotherapeutic applications. PMID:19101152

  2. PET and SPECT imaging of a radiolabeled minigastrin analogue conjugated with DOTA, NOTA, and NODAGA and labeled with (64)Cu, (68)Ga, and (111)In.

    PubMed

    Roosenburg, S; Laverman, P; Joosten, L; Cooper, M S; Kolenc-Peitl, P K; Foster, J M; Hudson, C; Leyton, J; Burnet, J; Oyen, W J G; Blower, P J; Mather, S J; Boerman, O C; Sosabowski, J K

    2014-11-03

    Cholecystokinin-2 (CCK-2) receptors, overexpressed in cancer types such as small cell lung cancers (SCLC) and medullary thyroid carcinomas (MTC), may serve as targets for peptide receptor radionuclide imaging. A variety of CCK and gastrin analogues has been developed, but a major drawback is metabolic instability or high kidney uptake. The minigastrin analogue PP-F11 has previously been shown to be a promising peptide for imaging of CCK-2 receptor positive tumors and was therefore further evaluated. The peptide was conjugated with one of the macrocyclic chelators DOTA, NOTA, or NODAGA. The peptide conjugates were then radiolabeled with either (68)Ga, (64)Cu, or (111)In. All (radio)labeled compounds were evaluated in vitro (IC50) and in vivo (biodistribution and PET/CT and SPECT/CT imaging). IC50 values were in the low nanomolar range for all compounds (0.79-1.51 nM). In the biodistribution studies, (68)Ga- and (111)In-labeled peptides showed higher tumor-to-background ratios than the (64)Cu-labeled compounds. All tested radiolabeled compounds clearly visualized the CCK2 receptor positive tumor in PET or SPECT imaging. The chelator did not seem to affect in vivo behavior of the peptide for (111)In- and (68)Ga-labeled peptides. In contrast, the biodistribution of the (64)Cu-labeled peptides showed high uptake in the liver and in other organs, most likely caused by high blood levels, probably due to dissociation of (64)Cu from the chelator and subsequent transchelation to proteins. Based on the present study, (68)Ga-DOTA-PP-F11 might be a promising radiopharmaceutical for PET/CT imaging of CCK2 receptor expressing tumors such as MTC and SCLC. Clinical studies are warranted to investigate the potential of this tracer.

  3. Visualizing Implanted Tumors in Mice with Magnetic Resonance Imaging Using Magnetotactic Bacteria

    PubMed Central

    Benoit, Michael R.; Mayer, Dirk; Barak, Yoram; Chen, Ian Y.; Hu, Wei; Cheng, Zhen; Wang, Shan X.; Spielman, Daniel M.; Gambhir, Sanjiv S.; Matin, A.

    2012-01-01

    Purpose To determine if magnetotactic bacteria can target tumors in mice and provide positive contrast for visualization using magnetic resonance imaging. Experimental Design The ability of the magnetotactic bacterium, Magnetospirillum magneticum AMB-1 (referred to from here as AMB-1), to confer positive magnetic resonance imaging contrast was determined in vitro and in vivo. For the latter studies, AMB-1 were injected either i.t. or i.v. Bacterial growth conditions were manipulated to produce small (~25-nm diameter) magnetite particles, which were observed using transmission electron microscopy. Tumor targeting was confirmed using 64Cu-labeled bacteria and positron emission tomography and by determination of viable cell counts recovered from different organs and the tumor. Results We show that AMB-1 bacteria with small magnetite particles generate T1-weighted positive contrast, enhancing in vivo visualization by magnetic resonance imaging. Following i.v. injection of 64Cu-labeled AMB-1, positron emission tomography imaging revealed increasing colonization of tumors and decreasing infection of organs after 4 hours. Viable cell counts showed that, by day 6, the bacteria had colonized tumors but were cleared completely from other organs. Magnetic resonance imaging showed a 1.22-fold (P = 0.003) increased positive contrast in tumors on day 2 and a 1.39-fold increase (P = 0.0007) on day 6. Conclusion Magnetotactic bacteria can produce positive magnetic resonance imaging contrast and colonize mouse tumor xenografts, providing a potential tool for improved magnetic resonance imaging visualization in preclinical and translational studies to track cancer. PMID:19671860

  4. Theranostic probe for simultaneous in vivo photoacoustic imaging and confined photothermolysis by pulsed laser at 1064 nm in 4T1 breast cancer model

    NASA Astrophysics Data System (ADS)

    Zhou, Min; Ku, Geng; Pageon, Laura; Li, Chun

    2014-11-01

    Here, we report that polyethylene glycol (PEG)-coated copper(ii) sulfide nanoparticles (PEG-CuS NPs) with their peak absorption tuned to 1064 nm could be used both as a contrast agent for photoacoustic tomographic imaging of mouse tumor vasculature and as a mediator for confined photothermolysis of tumor cells in an orthotopic syngeneic 4T1 breast tumor model. PEG-CuS NPs showed stronger photoacoustic signal than hollow gold nanospheres and single-wall carbon nanotubes at 1064 nm. MicroPET imaging of 4T1 tumor-bearing mice showed a gradual accumulation of the NPs in the tumor over time. About 6.5% of injected dose were taken up in each gram of tumor tissue at 24 h after intravenous injection of 64Cu-labeled PEG-CuS NPs. For both photoacoustic imaging and therapeutic studies, nanosecond (ns)-pulsed laser was delivered with Q-switched Nd:YAG at a wavelength of 1064 nm. Unlike conventional photothermal ablation therapy mediated by continuous wave laser with which heat could spread to the surrounding normal tissue, interaction of CuS NPs with short pulsed laser deliver heat rapidly to the treatment volume keeping the thermal damage confined to the target tissues. Our data demonstrated that it is possible to use a single-compartment nanoplatform to achieve both photoacoustic tomography and highly selective tumor destruction at 1064 nm in small animals.Here, we report that polyethylene glycol (PEG)-coated copper(ii) sulfide nanoparticles (PEG-CuS NPs) with their peak absorption tuned to 1064 nm could be used both as a contrast agent for photoacoustic tomographic imaging of mouse tumor vasculature and as a mediator for confined photothermolysis of tumor cells in an orthotopic syngeneic 4T1 breast tumor model. PEG-CuS NPs showed stronger photoacoustic signal than hollow gold nanospheres and single-wall carbon nanotubes at 1064 nm. MicroPET imaging of 4T1 tumor-bearing mice showed a gradual accumulation of the NPs in the tumor over time. About 6.5% of injected dose were

  5. PET of Follicle-Stimulating Hormone Receptor: Broad Applicability to Cancer Imaging

    PubMed Central

    Hong, Hao; Yan, Yongjun; Shi, Sixiang; Graves, Stephen A.; Krasteva, Lazura K.; Nickles, Robert J.; Yang, Min; Cai, Weibo

    2015-01-01

    Selective overexpression of follicle-stimulating hormone receptor (FSHR) inside the vascular endothelium of tumors has been confirmed to play critical roles in angiogenesis, tumor invasion, and metastases. The expression level of FSHR correlates strongly with the response of tumors to antiangiogenic therapies. In this study, an immunoPET tracer was developed for imaging of FSHR in different cancer types. A monoclonal antibody (FSHR-mAb) against FSHR was conjugated with S-2-(4-isothiocyanatobenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid (p-SCN-Bn-NOTA) and used for subsequent 64Cu-labeling. NOTA-FSHR-mAb preserved FSHR specificity/affinity, confirmed by flow cytometry measurements. 64Cu-labeling was successfully conducted with decent yields (~ 25%) and high specific activity (0.93 GBq/mg). The uptake of 64Cu-NOTA-FSHR-mAb was 3.6 ± 0.8, 13.2 ± 0.7, and 14.6 ± 0.4%ID/g in FSHR-positive CAOV-3 tumors at 4, 24, and 48 h post-injection, respectively (n = 3), significantly higher (p<0.05) than that in FSHR-negative SKOV-3 tumors (2.3 ± 1.2, 8.0 ± 0.9, and 9.1 ± 1.3 %ID/g at 4, 24, and 48 h post-injection, respectively (n = 3)) except at 4 h p.i. FSHR-relevant uptake of 64Cu-NOTA-FSHR-mAb was also readily observed in other tumor types (e.g. triple-negative breast tumor MDA-MB-231 or prostate tumor PC-3). Histology studies showed universal FSHR expression in microvasculature of these four tumor types and also prominent expression in tumor cells of CAOV-3, PC-3, and MDA-MB-231. Correlations between tumor FSHR level and uptake of 64Cu-NOTA-FSHR-mAb were witnessed in this study. FSHR-specific uptake of 64Cu-NOTA-FSHR mAb in different tumors enables its applicability for future cancer theranostic applications and simultaneously establishes FSHR as a promising clinical target for cancer. PMID:25581441

  6. (68)Ga/DOTA- and (64)Cu/NOTA-phthalocyanine conjugates as fluorescent/PET bimodal imaging probes.

    PubMed

    Ranyuk, Elena; Lebel, Réjean; Bérubé-Lauzière, Yves; Klarskov, Klaus; Lecomte, Roger; van Lier, Johan E; Guérin, Brigitte

    2013-09-18

    In this paper, we describe the synthesis and characterization of a series of new bimodal probes combining water-soluble sulfonated zinc phthalocyanine (ZnPc) as a fluorescence imaging unit and either (68)Ga/1,4,7,10-tetraazocyclododecane-N,N'N″,N'″-tetraacetic acid (DOTA) or (64)Cu/1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) for PET imaging. The two moieties were linked through aliphatic chains of different lengths to modulate amphiphilicity. Labeling of DOTA- or NOTA-ZnPc conjugates with (68)Ga (t1/2 = 68 min) and (64)Cu (t1/2 = 12.7 h) was performed at 100 °C for 15 min with >90% efficiency for all conjugates. In vitro plasma stability assays demonstrated high stability of the (64)Cu/NOTA-ZnPc conjugate, which remained intact over a 24 h time period, and reasonably high stability of the (68)Ga/DOTA-ZnPc conjugate, which released up to 7% of free (68)Ga over a 3 h period. Based on in vitro plasma stability results, we performed biodistribution studies on two (64)Cu-labeled derivatives, which allowed us to select a single candidate for preliminary in vivo experiments. Fluorescence and PET imaging confirmed the potential of these novel conjugates to act as bimodal probes.

  7. Size Dependent Kinetics of Gold Nanorods in EPR Mediated Tumor Delivery

    PubMed Central

    Tong, Xiao; Wang, Zhantong; Sun, Xiaolian; Song, Jibin; Jacobson, Orit; Niu, Gang; Kiesewetter, Dale O.; Chen, Xiaoyuan

    2016-01-01

    Gold nanorods (AuNR) have been intensively used in nanomedicine for cancer diagnostics and therapy, due to their excellent plasmonic photothermal properties. Tuning the size and aspect ratio of AuNR tailors the localized surface plasmon resonance (LSPR) in the NIR spectrum at which biological tissues are transparent, thus enables specific and effective treatment. The AuNR extravasates into tumor interstitium through enhanced permeation and retention (EPR) effect. Efficient AuNR based cancer therapy requires efficient AuNR tumor delivery. However, the size of AuNR can dramatically affect its blood circulation and tumor accumulation. Here we proposed for the first time a systematic framework to investigate the size-dependent kinetics of AuNRs during EPR mediated tumor delivery. By using 64Cu-labeled AuNRs with positron emission tomography (PET) and kinetic modeling, the in vivo uptake and kinetics of 64Cu-AuNR during its blood circulation, tumor accumulation and elimination were studied both in vitro and in vivo. The results of different sized AuNRs were compared and the optimum size of AuNR was suggested for EPR mediated tumor delivery. Our study provides a better understanding of the in vivo behavior of AuNR, which can help future design of nanomaterials for cancer imaging and therapy. PMID:27698939

  8. In Vivo Tumor Targeting and Image-Guided Drug Delivery with Antibody-Conjugated, Radiolabeled Mesoporous Silica Nanoparticles

    PubMed Central

    Chen, Feng; Hong, Hao; Zhang, Yin; Valdovinos, Hector F.; Shi, Sixiang; Kwon, Glen S.; Theuer, Charles P.; Barnhart, Todd E.; Cai, Weibo

    2013-01-01

    Since the first use of biocompatible mesoporous silica (mSiO2) nanoparticles as drug delivery vehicles, in vivo tumor targeted imaging and enhanced anti-cancer drug delivery has remained a major challenge. In this work, we describe the development of functionalized mSiO2 nanoparticles for actively targeted positron emission tomography (PET) imaging and drug delivery in 4T1 murine breast tumor-bearing mice. Our structural design involves the synthesis, surface functionalization with thiol groups, PEGylation, TRC105 antibody (specific for CD105/endoglin) conjugation, and 64Cu-labeling of uniform 80 nm sized mSiO2 nanoparticles. Systematic in vivo tumor targeting studies clearly demonstrated that 64Cu-NOTA-mSiO2-PEG-TRC105 could accumulate prominently at the 4T1 tumor site via both the enhanced permeability and retention effect and TRC105-mediated binding to tumor vasculature CD105. As a proof-of-concept, we also demonstrated successful enhanced tumor targeted delivery of doxorubicin (DOX) in 4T1 tumor-bearing mice after intravenous injection of DOX-loaded NOTA-mSiO2-PEG-TRC105, which holds great potential for future image-guided drug delivery and targeted cancer therapy. PMID:24083623

  9. Copper(II) chemistry of the functionalized macrocycle cyclam tetrapropionic acid.

    PubMed

    Comba, Peter; Emmerling, Franziska; Jakob, Maik; Kraus, Werner; Kubeil, Manja; Morgen, Michael; Pietzsch, Jens; Stephan, Holger

    2013-05-07

    The Cu(II) complex of H(4)TETP (H(4)TETP = 1,4,8,11-tetraazatetradecane-1,4,8,11-tetrapropionic acid) is five-coordinate with a distorted square-pyramidal structure (τ = 0.45; i.e. the geometry is nearly half-way between square-pyramidal and trigonal-bipyramidal) and a relatively long Cu-N and a short Cu-O bond; the comparison between powder and solution electronic spectroscopy, the frozen solution EPR spectrum and ligand-field-based calculations (angular overlap model, AOM) indicate that the solution and solid state structures are very similar, i.e. the complex has a relatively low "in-plane" and a significant axial ligand field with a d(x(2)-y(2)) ground state. The ligand-enforced structure is therefore shown to lead to a partially quenched Jahn-Teller distortion and to a relatively low complex stability, lower than with the corresponding acetate-derived ligand H(4)TETA. This is confirmed by potentiometric titration and by the biodistribution with (64)Cu-labeled ligands which show that the uptake in the liver is significantly increased with the H(4)TETP-based system.

  10. Sequential Drug Release and Enhanced Photothermal and Photoacoustic Effect of Hybrid Reduced Graphene Oxide-Loaded Ultrasmall Gold Nanorod Vesicles for Cancer Therapy

    PubMed Central

    Song, Jibin; Yang, Xiangyu; Jacobson, Orit; Lin, Lisen; Huang, Peng; Niu, Gang; Ma, Qingjie; Chen, Xiaoyuan

    2017-01-01

    We report a hybrid reduced graphene oxide (rGO)-loaded ultrasmall plasmonic gold nanorod vesicle (rGO-AuNRVe) (~65 nm in size) with remarkably amplified photoacoustic (PA) performance and photothermal effects. The hybrid vesicle also exhibits a high loading capacity of doxorubicin (DOX), as both the cavity of the vesicle and the large surface area of the encapsulated rGO can be used for loading DOX, making it an excellent drug carrier. The loaded DOX is released sequentially: near-infrared photothermal heating induces DOX release from the vesicular cavity, and an intracellular acidic environment induces DOX release from the rGO surface. Positron emission tomography imaging showed high passive U87MG tumor accumulation of 64Cu-labeled rGO-AuNRVes (~9.7% ID/g at 24 h postinjection) and strong PA signal in the tumor region. Single intravenous injection of rGO-AuNRVe-DOX followed by low-power-density 808 nm laser irradiation (0.25 W/cm2) revealed effective inhibition of tumor growth due to the combination of chemo- and photothermal therapies. The rGO-AuNRVe-DOX capable of sequential DOX release by laser light and acid environment may have the potential for clinical translation to treat cancer patients with tumors accessible by light. PMID:26308265

  11. Improved Tumor Uptake by Optimizing Liposome Based RES Blockade Strategy

    PubMed Central

    Sun, Xiaolian; Yan, Xuefeng; Jacobson, Orit; Sun, Wenjing; Wang, Zhantong; Tong, Xiao; Xia, Yuqiong; Ling, Daishun; Chen, Xiaoyuan

    2017-01-01

    Minimizing the sequestration of nanomaterials (NMs) by the reticuloendothelial system (RES) can enhance the circulation time of NMs, and thus increase their tumor-specific accumulation. Liposomes are generally regarded as safe (GRAS) agents that can block the RES reversibly and temporarily. With the help of positron emission tomography (PET), we monitored the in vivo tissue distribution of 64Cu-labeled 40 × 10 nm gold nanorods (Au NRs) after pretreatment with liposomes. We systematically studied the effectiveness of liposome administration by comparing (1) differently charged liposomes; (2) different liposome doses; and (3) varying time intervals between liposome dose and NR dose. By pre-injecting 400 μmol/kg positively charged liposomes into mice 5 h before the Au NRs, the liver and spleen uptakes of Au NRs decreased by 30% and 53%, respectively. Significantly, U87MG tumor uptake of Au NRs increased from 11.5 ± 1.1 %ID/g to 16.1 ± 1.3 %ID/g at 27 h post-injection. Quantitative PET imaging is a valuable tool to understand the fate of NMs in vivo and cationic liposomal pretreatment is a viable approach to reduce RES clearance, prolong circulation, and improve tumor uptake. PMID:28042337

  12. Radiopharmaceuticals in Preclinical and Clinical Development for Monitoring of Therapy with PET

    PubMed Central

    Dunphy, Mark PS.; Lewis, Jason S.

    2010-01-01

    This review article discusses PET agents, other than 18F-FDG, with the potential to monitor the response to therapy before, during, or after therapeutic intervention. This review deals primarily with non–18F-FDG PET tracers that are in the final stages of preclinical development or in the early stages of clinical application for monitoring the therapeutic response. Four sections related to the nature of the tracers are included: radiotracers of DNA synthesis, such as the 2 most promising agents, the thymidine analogs 3′-18F-fluoro-3′-deoxythymidine and 18F-1-(2′-deoxy-2′-fluoro-β-d-arabinofuranosyl)thymine; agents for PET imaging of hypoxia within tumors, such as 60/62/64Cu-labeled diacetyl-bis(N4-methylthiosemicarbazone) and 18F-fluoromisonidazole; amino acids for PET imaging, including the most popular such agent, l-[methyl-11C]methionine; and agents for the imaging of tumor expression of androgen and estrogen receptors, such as 16β-18F-fluoro-5α-dihydrotestosterone and 16α-18F-fluoro-17β-estradiol, respectively. PMID:19380404

  13. Hormonally produced changes in caeruloplasmin synthesis and secretion in primary cultured rat hepatocytes. Relationship to hepatic copper metabolism.

    PubMed Central

    Weiner, A L; Cousins, R J

    1983-01-01

    Hormonally produced changes in the synthesis and secretion of the serum copper-containing protein caeruloplasmin were studied in primary cultures of rat liver parenchymal cells isolated by the collagenase-perfusion technique. A rabbit antibody directed against rat caeruloplasmin was used to immunoprecipitate labelled caeruloplasmin. Isolated liver cells synthesized and secreted caeruloplasmin over a period of 3 days. Synthesis and secretion of this protein was enhanced when cells were treated with dexamethasone. The accumulation of copper was also moderately enhanced with glucocorticoid treatment. Inclusion of adrenaline in the culture medium resulted in elevated incorporation of copper into newly synthesized caeruloplasmin as well as an increase in 64Cu-labelled caeruloplasmin in the culture medium. However, adrenaline did not seem to increase the secretion of 3H-labelled protein, despite the elevation in secreted 64Cu-caeruloplasmin. This may be due to a large increase in the intracellular pool of 64Cu caused by enhanced accumulation of this metal when adrenaline is included in the incubation medium. Enhanced copper accumulation was also seen when cells were treated with glucagon. Adrenaline-stimulated accumulation of 64Cu could be inhibited by including phenoxybenzamine, an alpha-adrenergic blocker, in the culture medium. Elevation of extracellular copper caused enhancement in the detection of labelled caeruloplasmin in the medium of cultured cells, probably owing to the ability of this metal to stabilize the protein. Images Fig. 1. PMID:6882374

  14. Comparative study of 64Cu/NOTA-[D-Tyr6,βAla11,Thi13,Nle14]BBN(6-14) monomer and dimers for prostate cancer PET imaging.

    PubMed

    Fournier, Patrick; Dumulon-Perreault, Véronique; Ait-Mohand, Samia; Langlois, Réjean; Bénard, François; Lecomte, Roger; Guérin, Brigitte

    2012-02-14

    Gastrin-releasing peptide receptors [GRPR] are highly over-expressed in multiple cancers and have been studied as a diagnostic target. Multimeric gastrin-releasing peptides are expected to have enhanced tumor uptake and affinity for GRPR. In this study, a 64Cu-labeled 1,4,7-triazacyclononane-1,4,7-triacetic acid [NOTA]-monomer and two NOTA-dimers of [D-Tyr6,βAla11, Thi13, Nle14]bombesin(6-14) ] [BBN(6-14)] were compared. Monomeric and dimeric peptides were synthesized on solid phase support and radiolabeled with 64Cu. NOTA-dimer 1 consists of asymmetrically linked BBN(6-14), while NOTA-dimer 2 has similar spacer between the two BBN(6-14) ligands and the chelator. In vitro GRPR-binding affinities were determined with competitive binding assays on PC3 human prostate cancer cells. In vivo stability and biodistribution of radiolabeled compounds were assessed in Balb/c mice. Cellular uptake and efflux were measured with radiolabeled NOTA-monomer and NOTA-dimer 2 on PC3 cells for up to 4 h. In vivo biodistribution kinetics were measured in PC3 tumor-bearing Balb/c nude mice by μ-positron emission tomography [μPET] imaging and confirmed by dissection and counting. NOTA-monomer, NOTA-dimers 1 and 2 were prepared with purity of 99%. The inhibition constants of the three BBN peptides were comparable and in the low nanomolar range. All 64Cu-labeled peptides were stable up to 24 h in mouse plasma and 1 h in vivo. 64Cu/NOTA-dimer 2 featuring a longer spacer between the two BBN(6-14) ligands is a more potent GRPR-targeting probe than 64Cu/NOTA-dimer 1. PC3 tumor uptake profiles are slightly different for 64Cu/NOTA-monomer and 64Cu/NOTA-dimer 2; the monomeric BBN-peptide tracer exhibited higher tumor uptake during the first 0.5 h and a fast renal clearance resulting in higher tumor-to-muscle ratio when compared to 64Cu/NOTA-dimer 2. The latter exhibited higher tumor-to-blood ratio and was retained longer at the tumor site when compared to 64Cu/NOTA-monomer. Lower ratios of

  15. High Resolution PET with 250 micrometer LSO Detectors and Adaptive Zoom

    SciTech Connect

    Cherry, Simon R.; Qi, Jinyi

    2012-01-08

    There have been impressive improvements in the performance of small-animal positron emission tomography (PET) systems since their first development in the mid 1990s, both in terms of spatial resolution and sensitivity, which have directly contributed to the increasing adoption of this technology for a wide range of biomedical applications. Nonetheless, current systems still are largely dominated by the size of the scintillator elements used in the detector. Our research predicts that developing scintillator arrays with an element size of 250 {micro}m or smaller will lead to an image resolution of 500 {micro}m when using 18F- or 64Cu-labeled radiotracers, giving a factor of 4-8 improvement in volumetric resolution over the highest resolution research systems currently in existence. This proposal had two main objectives: (i) To develop and evaluate much higher resolution and efficiency scintillator arrays that can be used in the future as the basis for detectors in a small-animal PET scanner where the spatial resolution is dominated by decay and interaction physics rather than detector size. (ii) To optimize one such high resolution, high sensitivity detector and adaptively integrate it into the existing microPET II small animal PET scanner as a 'zoom-in' detector that provides higher spatial resolution and sensitivity in a limited region close to the detector face. The knowledge gained from this project will provide valuable information for building future PET systems with a complete ring of very high-resolution detector arrays and also lay the foundations for utilizing high-resolution detectors in combination with existing PET systems for localized high-resolution imaging.

  16. A Pretargeted Approach for the Multimodal PET/NIRF Imaging of Colorectal Cancer

    PubMed Central

    Adumeau, Pierre; Carnazza, Kathryn E.; Brand, Christian; Carlin, Sean D.; Reiner, Thomas; Agnew, Brian J.; Lewis, Jason S.; Zeglis, Brian M.

    2016-01-01

    The complementary nature of positron emission tomography (PET) and near-infrared fluorescence (NIRF) imaging makes the development of strategies for the multimodal PET/NIRF imaging of cancer a very enticing prospect. Indeed, in the context of colorectal cancer, a single multimodal PET/NIRF imaging agent could be used to stage the disease, identify candidates for surgical intervention, and facilitate the image-guided resection of the disease. While antibodies have proven to be highly effective vectors for the delivery of radioisotopes and fluorophores to malignant tissues, the use of radioimmunoconjugates labeled with long-lived nuclides such as 89Zr poses two important clinical complications: high radiation doses to the patient and the need for significant lag time between imaging and surgery. In vivo pretargeting strategies that decouple the targeting vector from the radioactivity at the time of injection have the potential to circumvent these issues by facilitating the use of positron-emitting radioisotopes with far shorter half-lives. Here, we report the synthesis, characterization, and in vivo validation of a pretargeted strategy for the multimodal PET and NIRF imaging of colorectal carcinoma. This approach is based on the rapid and bioorthogonal ligation between a trans-cyclooctene- and fluorophore-bearing immunoconjugate of the huA33 antibody (huA33-Dye800-TCO) and a 64Cu-labeled tetrazine radioligand (64Cu-Tz-SarAr). In vivo imaging experiments in mice bearing A33 antigen-expressing SW1222 colorectal cancer xenografts clearly demonstrate that this approach enables the non-invasive visualization of tumors and the image-guided resection of malignant tissue, all at only a fraction of the radiation dose created by a directly labeled radioimmunoconjugate. Additional in vivo experiments in peritoneal and patient-derived xenograft models of colorectal carcinoma reinforce the efficacy of this methodology and underscore its potential as an innovative and useful

  17. (64)Cu-PSMA-617 PET/CT Imaging of Prostate Adenocarcinoma: First In-Human Studies.

    PubMed

    Grubmüller, Bernhard; Baum, Richard P; Capasso, Enza; Singh, Aviral; Ahmadi, Yasaman; Knoll, Peter; Floth, Andreas; Righi, Sergio; Zandieh, Shahin; Meleddu, Carlo; Shariat, Shahrokh F; Klingler, Hans Christoph; Mirzaei, Siroos

    2016-10-07

    The prostate-specific membrane antigen (PSMA) is a cell surface protein, which is overexpressed in nearly all cases of prostate cancer (PCa). PET imaging with (68)Ga-PSMA-HBED-CC has recently found widespread application in the diagnosis of recurrent PCa. In this study, the diagnostic potential of (64)Cu-labeled PSMA ligand (PSMA-617) PET in patients with PCa has been investigated. The study was conducted simultaneously at two nuclear medicine centers, Austria (Vienna, Center 1) and Germany (Bad Berka, Center 2). The patients (n = 29) included in this study were referred for PET (Center 1, 21 patients) or PET/CT (Center 2, 8 patients) imaging with either a high suspicion of recurrent disease or for possible surgical or PSMA radioligand therapy planning. PET images of the whole body were performed at 1 hour p.i. and additional images of the pelvis at 2 hours p.i. In 23 of 29 patients, at least one focus of pathological tracer uptake suspicious for primary disease in the prostate lobe or recurrent disease was detected. Among healthy organs, the salivary glands, kidneys, and liver showed the highest radiotracer uptake. Lesions suspicious for PCa were detected with excellent contrast as early as 1 hour p.i. with high detection rates even at low prostate-specific antigen (PSA) levels. The preliminary results of this study demonstrate the high potential of (64)Cu-PSMA ligand PET/CT imaging in patients with recurrent disease and in the primary staging of selected patients with progressive local disease. The acquired PET images showed an excellent resolution of the detected lesions with very high lesion-to- background contrast. Furthermore, the long half-life of (64)Cu allows distribution of the tracer to clinical PET centers that lack radiochemistry facilities for the preparation of (68)Ga-PSMA ligand (satellite concept).

  18. Pretargeted PET Imaging Using a Site-Specifically Labeled Immunoconjugate.

    PubMed

    Cook, Brendon E; Adumeau, Pierre; Membreno, Rosemery; Carnazza, Kathryn E; Brand, Christian; Reiner, Thomas; Agnew, Brian J; Lewis, Jason S; Zeglis, Brian M

    2016-08-17

    In recent years, both site-specific bioconjugation techniques and bioorthogonal pretargeting strategies have emerged as exciting technologies with the potential to improve the safety and efficacy of antibody-based nuclear imaging. In the work at hand, we have combined these two approaches to create a pretargeted PET imaging strategy based on the rapid and bioorthogonal inverse electron demand Diels-Alder reaction between a (64)Cu-labeled tetrazine radioligand ((64)Cu-Tz-SarAr) and a site-specifically modified huA33-trans-cyclooctene immunoconjugate ((ss)huA33-PEG12-TCO). A bioconjugation strategy that harnesses enzymatic transformations and strain-promoted azide-alkyne click chemistry was used to site-specifically append PEGylated TCO moieties to the heavy chain glycans of the colorectal cancer-targeting huA33 antibody. Preclinical in vivo validation studies were performed in athymic nude mice bearing A33 antigen-expressing SW1222 human colorectal carcinoma xenografts. To this end, mice were administered (ss)huA33-PEG12-TCO via tail vein injection and-following accumulation intervals of 24 or 48 h-(64)Cu-Tz-SarAr. PET imaging and biodistribution studies reveal that this strategy clearly delineates tumor tissue as early as 1 h post-injection (6.7 ± 1.7%ID/g at 1 h p.i.), producing images with excellent contrast and high tumor-to-background activity concentration ratios (tumor:muscle = 21.5 ± 5.6 at 24 h p.i.). Furthermore, dosimetric calculations illustrate that this pretargeting approach produces only a fraction of the overall effective dose (0.0214 mSv/MBq; 0.079 rem/mCi) of directly labeled radioimmunoconjugates. Ultimately, this method effectively facilitates the high contrast pretargeted PET imaging of colorectal carcinoma using a site-specifically modified immunoconjugate.

  19. A Pretargeted Approach for the Multimodal PET/NIRF Imaging of Colorectal Cancer.

    PubMed

    Adumeau, Pierre; Carnazza, Kathryn E; Brand, Christian; Carlin, Sean D; Reiner, Thomas; Agnew, Brian J; Lewis, Jason S; Zeglis, Brian M

    2016-01-01

    The complementary nature of positron emission tomography (PET) and near-infrared fluorescence (NIRF) imaging makes the development of strategies for the multimodal PET/NIRF imaging of cancer a very enticing prospect. Indeed, in the context of colorectal cancer, a single multimodal PET/NIRF imaging agent could be used to stage the disease, identify candidates for surgical intervention, and facilitate the image-guided resection of the disease. While antibodies have proven to be highly effective vectors for the delivery of radioisotopes and fluorophores to malignant tissues, the use of radioimmunoconjugates labeled with long-lived nuclides such as (89)Zr poses two important clinical complications: high radiation doses to the patient and the need for significant lag time between imaging and surgery. In vivo pretargeting strategies that decouple the targeting vector from the radioactivity at the time of injection have the potential to circumvent these issues by facilitating the use of positron-emitting radioisotopes with far shorter half-lives. Here, we report the synthesis, characterization, and in vivo validation of a pretargeted strategy for the multimodal PET and NIRF imaging of colorectal carcinoma. This approach is based on the rapid and bioorthogonal ligation between a trans-cyclooctene- and fluorophore-bearing immunoconjugate of the huA33 antibody (huA33-Dye800-TCO) and a (64)Cu-labeled tetrazine radioligand ((64)Cu-Tz-SarAr). In vivo imaging experiments in mice bearing A33 antigen-expressing SW1222 colorectal cancer xenografts clearly demonstrate that this approach enables the non-invasive visualization of tumors and the image-guided resection of malignant tissue, all at only a fraction of the radiation dose created by a directly labeled radioimmunoconjugate. Additional in vivo experiments in peritoneal and patient-derived xenograft models of colorectal carcinoma reinforce the efficacy of this methodology and underscore its potential as an innovative and useful

  20. ImmunoPET of Tissue Factor in Pancreatic Cancer

    PubMed Central

    Hong, Hao; Zhang, Yin; Nayak, Tapas R.; Engle, Jonathan W.; Wong, Hing C.; Liu, Bai; Barnhart, Todd E.; Cai, Weibo

    2012-01-01

    Upregulation of tissue factor (TF) expression leads to increased patient morbidity and mortality in many solid tumor types. The goal of this study was to develop a positron emission tomography (PET) tracer for imaging of TF expression in pancreatic cancer. Methods ALT-836, a chimeric anti-human TF monoclonal antibody, was conjugated to 2-S-(4-isothiocyanatobenzyl)-1, 4, 7-triazacyclononane-1, 4, 7-triacetic acid (p-SCN-Bn-NOTA) and labeled with 64Cu. To compare the TF binding affinity of ALT-836 and NOTA-ALT-836, flow cytometry analysis was performed in three pancreatic cancer cell lines with different expression level of TF (from low to high: PANC-1, ASPC-1, and BXPC-3). PET imaging, biodistribution, blocking, and histology studies were performed on pancreatic tumor-bearing mice to evaluate the ability and specificity of 64Cu-NOTA-ALT-836 to target TF in vivo. Results There was no difference in TF binding affinity between ALT-836 and NOTA-ALT-836. 64Cu-labeling was achieved with high yield and specific activity. Serial PET imaging revealed that the uptake of 64Cu-NOTA-ALT-836 in BXPC-3 tumors (high TF expression) was 5.7 ± 0.5, 10.3 ± 0.5, and 16.5 ± 2.6 %ID/g at 4, 24, and 48 h post-injection respectively (n = 4), significantly higher than that in the PANC-1 and ASPC-1 tumors. Biodistribution data as measured by gamma counting were consistent with the PET findings. Blocking experiments and histology further confirmed the TF specificity of 64Cu-NOTA-ALT-836. Conclusion Herein we report the first successful PET imaging of TF expression. Persistent and TF-specific uptake of 64Cu-NOTA-ALT-836 was observed in pancreatic cancer models. PMID:22988057

  1. Evaluation of H2CHXdedpa, H2dedpa- and H2CHXdedpa-N,N'-propyl-2-NI ligands for (64)Cu(ii) radiopharmaceuticals.

    PubMed

    Ramogida, Caterina F; Boros, Eszter; Patrick, Brian O; Zeisler, Stefan K; Kumlin, Joel; Adam, Michael J; Schaffer, Paul; Orvig, Chris

    2016-08-16

    The chiral acyclic "pa" ligand (pa = picolinic acid) H2CHXdedpa (N4O2) and two NI-containing dedpa analogues (H2CHXdedpa-N,N'-propyl-2-NI, H2dedpa-N,N'-propyl-2-NI, NI = nitroimidazole) were studied as chelators for copper radiopharmaceuticals (CHX = cyclohexyl, H2dedpa = 1,2-[[carboxypyridin-2-yl]methylamino]ethane). The hexadentate ligand H2CHXdedpa was previously established as a superb system for (67/68)Ga radiochemistry. The solid state X-ray crystal structures of [Cu(CHXdedpa-N,N'-propyl-2-NI)] and [Cu(dedpa-N,N'-propyl-2-NI)] reveal the predicted hexadentate, distorted octahedral binding of the copper(ii) ion. Cyclic voltammetry of [Cu(dedpa-N,N'-propyl-2-NI)] shows that there is one reversible couple associated with the NI redox, and one irreversible but reproducible couple attributed to the Cu(ii)/Cu(i) redox cycle. Quantitative radiolabeling (>99%) of CHXdedpa(2-) and (dedpa-N,N'-propyl-2-NI)(2-) with (64)Cu was achieved under fast and efficient labeling conditions (10 min, RT, 0.5 M sodium acetate buffer, pH 5.5) at ligand concentrations as low as 10(-6) M. In vitro kinetic inertness studies of the (64)Cu labelled complexes were studied in human serum at 37 °C over 24 hours; [(64)Cu(CHXdedpa)] was found to be 98% stable compared to previously investigated [(64)Cu(dedpa)] which was only 72% intact after 24 hours.

  2. 64Cu antibody-targeting of the T-cell receptor and subsequent internalization enables in vivo tracking of lymphocytes by PET

    PubMed Central

    Griessinger, Christoph M.; Maurer, Andreas; Kesenheimer, Christian; Kehlbach, Rainer; Reischl, Gerald; Ehrlichmann, Walter; Bukala, Daniel; Harant, Maren; Cay, Funda; Brück, Jürgen; Nordin, Renate; Kohlhofer, Ursula; Rammensee, Hans-Georg; Quintanilla-Martinez, Leticia; Schaller, Martin; Röcken, Martin; Pichler, Bernd J.; Kneilling, Manfred

    2015-01-01

    T cells are key players in inflammation, autoimmune diseases, and immunotherapy. Thus, holistic and noninvasive in vivo characterizations of the temporal distribution and homing dynamics of lymphocytes in mammals are of special interest. Herein, we show that PET-based T-cell labeling facilitates quantitative, highly sensitive, and holistic monitoring of T-cell homing patterns in vivo. We developed a new T-cell receptor (TCR)-specific labeling approach for the intracellular labeling of mouse T cells. We found that continuous TCR plasma membrane turnover and the endocytosis of the specific 64Cu-monoclonal antibody (mAb)–TCR complex enables a stable labeling of T cells. The TCR–mAb complex was internalized within 24 h, whereas antigen recognition was not impaired. Harmful effects of the label on the viability, DNA-damage and apoptosis-necrosis induction, could be minimized while yielding a high contrast in in vivo PET images. We were able to follow and quantify the specific homing of systemically applied 64Cu-labeled chicken ovalbumin (cOVA)-TCR transgenic T cells into the pulmonary and perithymic lymph nodes (LNs) of mice with cOVA-induced airway delayed-type hypersensitivity reaction (DTHR) but not into pulmonary and perithymic LNs of naïve control mice or mice diseased from turkey or pheasant OVA-induced DTHR. Our protocol provides consequent advancements in the detection of small accumulations of immune cells in single LNs and specific homing to the sites of inflammation by PET using the internalization of TCR-specific mAbs as a specific label of T cells. Thus, our labeling approach is applicable to other cells with constant membrane receptor turnover. PMID:25587131

  3. PACE4-based molecular targeting of prostate cancer using an engineered ⁶⁴Cu-radiolabeled peptide inhibitor.

    PubMed

    Couture, Frédéric; Levesque, Christine; Dumulon-Perreault, Véronique; Ait-Mohand, Samia; D'Anjou, François; Day, Robert; Guérin, Brigitte

    2014-08-01

    The potential of PACE4 as a pharmacological target in prostate cancer has been demonstrated as this proprotein convertase is strongly overexpressed in human prostate cancer tissues and its inhibition, using molecular or pharmacological approaches, results in reduced cell proliferation and tumor progression in mouse tumor xenograft models. We developed a PACE4 high-affinity peptide inhibitor, namely, the multi-leucine (ML), and sought to determine whether this peptide could be exploited for the targeting of prostate cancer for diagnostic or molecular imaging purposes. We conjugated a bifunctional chelator 1,4,7-triazacyclononane-1,4,7- triacetic acid (NOTA) to the ML peptide for copper-64 ((64)Cu) labeling and positron emission tomography (PET)- based prostate cancer detection. Enzyme kinetic assays against recombinant PACE4 showed that the NOTA-modified ML peptide displays identical inhibitory properties compared to the unmodified peptide. In vivo biodistribution of the (64)Cu/NOTA-ML peptide evaluated in athymic nude mice bearing xenografts of two human prostate carcinoma cell lines showed a rapid and high uptake in PACE4-expressing LNCaP tumor at an early time point and in PACE4-rich organs. Co-injection of unlabeled peptide confirmed that tumor uptake was target-specific. PACE4-negative tumors displayed no tracer uptake 15 minutes after injection, while the kidneys, demonstrated high uptake due to rapid renal clearance of the peptide. The present study supports the feasibility of using a (64)Cu/NOTA-ML peptide for PACE4-targeted prostate cancer detection and PACE4 status determination by PET imaging but also provides evidence that ML inhibitor-based drugs would readily reach tumor sites under in vivo conditions for pharmacological intervention or targeted radiation therapy.

  4. PACE4-Based Molecular Targeting of Prostate Cancer Using an Engineered 64Cu-Radiolabeled Peptide Inhibitor1☆☆

    PubMed Central

    Couture, Frédéric; Levesque, Christine; Dumulon-Perreault, Véronique; Ait-Mohand, Samia; D’Anjou, François; Day, Robert; Guérin, Brigitte

    2014-01-01

    The potential of PACE4 as a pharmacological target in prostate cancer has been demonstrated as this proprotein convertase is strongly overexpressed in human prostate cancer tissues and its inhibition, using molecular or pharmacological approaches, results in reduced cell proliferation and tumor progression in mouse tumor xenograft models. We developed a PACE4 high-affinity peptide inhibitor, namely, the multi-leucine (ML), and sought to determine whether this peptide could be exploited for the targeting of prostate cancer for diagnostic or molecular imaging purposes. We conjugated a bifunctional chelator 1,4,7-triazacyclononane-1,4,7- triacetic acid (NOTA) to the ML peptide for copper-64 (64Cu) labeling and positron emission tomography (PET)– based prostate cancer detection. Enzyme kinetic assays against recombinant PACE4 showed that the NOTA-modified ML peptide displays identical inhibitory properties compared to the unmodified peptide. In vivo biodistribution of the 64Cu/NOTA-ML peptide evaluated in athymic nude mice bearing xenografts of two human prostate carcinoma cell lines showed a rapid and high uptake in PACE4-expressing LNCaP tumor at an early time point and in PACE4-rich organs. Co-injection of unlabeled peptide confirmed that tumor uptake was target-specific. PACE4-negative tumors displayed no tracer uptake 15 minutes after injection, while the kidneys, demonstrated high uptake due to rapid renal clearance of the peptide. The present study supports the feasibility of using a 64Cu/NOTA-ML peptide for PACE4-targeted prostate cancer detection and PACE4 status determination by PET imaging but also provides evidence that ML inhibitor–based drugs would readily reach tumor sites under in vivo conditions for pharmacological intervention or targeted radiation therapy. PMID:25220591

  5. Molecular imaging-based dose painting: a novel paradigm for radiation therapy prescription.

    PubMed

    Bentzen, Søren M; Gregoire, Vincent

    2011-04-01

    Dose painting is the prescription of a nonuniform radiation dose distribution to the target volume based on functional or molecular images shown to indicate the local risk of relapse. Two prototypical strategies for implementing this novel paradigm in radiation oncology are reviewed: subvolume boosting and dose painting by numbers. Subvolume boosting involves the selection of a "target within the target," defined by image segmentation on the basis of the quantitative information in the image or morphologically, and this is related to image-based target volume selection and delineation. Dose painting by numbers is a voxel-level prescription of dose based on a mathematical transformation of the image intensity of individual pixels. The quantitative use of images to decide both where and how to delivery radiation therapy in an individual case is also called theragnostic imaging. Dose painting targets are imaging surrogates for cellular or microenvironmental phenotypes associated with poor radioresponsiveness. In this review, the focus is on the following positron emission tomography tracers: FDG and choline as surrogates for tumor burden, fluorothymidine as a surrogate for proliferation (or cellular growth fraction) and hypoxia-sensitive tracers, including [(18)F] fluoromisonidazole, EF3, EF5, and (64)Cu-labeled copper(II) diacetyl-di(N(4)-methylthiosemicarbazone) as surrogates of cellular hypoxia. Research advances supporting the clinicobiological rationale for dose painting are reviewed as are studies of the technical feasibility of optimizing and delivering realistic dose painted radiation therapy plans. Challenges and research priorities in this exciting research field are defined and a possible design for a randomized clinical trial of dose painting is presented.

  6. Comparison of conjugation strategies of cross-bridged macrocyclic chelators with cetuximab for copper-64 radiolabeling and PET imaging of EGFR in colorectal tumor-bearing mice.

    PubMed

    Zeng, Dexing; Guo, Yunjun; White, Alexander G; Cai, Zhengxin; Modi, Jalpa; Ferdani, Riccardo; Anderson, Carolyn J

    2014-11-03

    Epidermal growth-factor receptor (EGFR) is overexpressed in a wide variety of solid tumors and has served as a well-characterized target for cancer imaging and therapy. Cetuximab was the first mAb targeting EGFR approved by the FDA for the treatment of metastatic colorectal and head and neck cancers. Previous studies showed that (64)Cu (T1/2 = 12.7 h; β(+) (17.4%)) labeled DOTA-cetuximab showed promise for PET imaging of EGFR-positive tumors; however the in vivo stability of this compound has been questioned. In this study, two recently developed cross-bridged macrocyclic chelators (CB-TE1A1P and CB-TE1K1P) were conjugated to cetuximab using standard NHS coupling procedures and/or strain-promoted azide-alkyne cycloaddition (SPAAC) methodologies. The radiolabeling and in vitro/vivo evaluation of the resulting cetuximab conjugates were compared. Improved Cu-64 labeling efficiency and high specific activity (684 kBq/μg, decay corrected to the end of bombardment) were obtained with the CB-TE1K1P-PEG4-click-cetuximab conjugate. Saturation binding assays indicated that the prepared cetuximab conjugates had comparable affinity (1.32-2.00 nM) in the HCT116 human colorectal tumor cell membranes. In the subsequent in vivo evaluation, (64)Cu-CB-TE1K1P-PEG4-click-cetuximab demonstrated more rapid renal clearance with a higher tumor/nontumor ratio than other (64)Cu-labeled cetuximab conjugates, and it shows the greatest promise for imaging and therapy of EGFR-positive tumors.

  7. Synthesis and Evaluation of New Generation Cross-Bridged Bifunctional Chelator for (64)Cu Radiotracers.

    PubMed

    Dale, Ajit V; An, Gwang Il; Pandya, Darpan N; Ha, Yeong Su; Bhatt, Nikunj; Soni, Nisarg; Lee, Hochun; Ahn, Heesu; Sarkar, Swarbhanu; Lee, Woonghee; Huynh, Phuong Tu; Kim, Jung Young; Gwon, Mi-Ri; Kim, Sung Hong; Park, Jae Gyu; Yoon, Young-Ran; Yoo, Jeongsoo

    2015-09-08

    Bifunctional chelators have been successfully used to construct (64)Cu-labeled radiopharmaceuticals. Previously reported chelators with cross-bridged cyclam backbones have various essential features such as high stability of the copper(II) complex, high efficiency of radiolabeling at room temperature, and good biological inertness of the radiolabeled complex, along with rapid body clearance. Here, we report a new generation propylene-cross-bridged chelator with hybrid acetate/phosphonate pendant groups (PCB-TE1A1P) developed with the aim of combining these key properties in a single chelator. The PCB-TE1A1P was synthesized from cyclam with good overall yield. The Cu(II) complex of our chelator showed good robustness in kinetic stability evaluation experiments, such as acidic decomplexation and cyclic voltammetry studies. The Cu(II) complex of PCB-TE1A1P remained intact under highly acidic conditions (12 M HCl, 90 °C) for 8 d and showed quasi-reversible reduction/oxidation peaks at -0.77 V in electrochemical studies. PCB-TE1A1P was successfully radiolabeled with (64)Cu ions in an acetate buffer at 60 °C within 60 min. The electrophoresis study revealed that the (64)Cu-PCB-TE1A1P complex has net negative charge in aqueous solution. The biodistribution and in vivo stability study profiles of (64)Cu-PCB-TE1A1P indicated that the radioactive complex was stable under physiological conditions and cleared rapidly from the body. A whole body positron emission tomography (PET) imaging study further confirmed high in vivo stability and fast clearance of the complex in mouse models. In conclusion, PCB-TE1A1P has good potential as a bifunctional chelator for (64)Cu-based radiopharmaceuticals, especially those involving peptides.

  8. Copper-64 labeled liposomes for imaging bone marrow.

    PubMed

    Lee, Sang-Gyu; Gangangari, Kishore; Kalidindi, Teja Muralidhar; Punzalan, Blesida; Larson, Steven M; Pillarsetty, Naga Vara Kishore

    2016-12-01

    Bone marrow is the soft tissue compartment inside the bones made up of hematopoietic cells, adipocytes, stromal cells, phagocytic cells, stem cells, and sinusoids. While [(18)F]-FLT has been utilized to image proliferative marrow, to date, there are no reports of particle based positron emission tomography (PET) imaging agents for imaging bone marrow. We have developed copper-64 labeled liposomal formulation that selectively targets bone marrow and therefore serves as an efficient PET probe for imaging bone marrow. Optimized liposomal formulations were prepared with succinyl PE, DSPC, cholesterol, and mPEG-DSPE (69:39:1:10:0.1) with diameters of 90 and 140nm, and were doped with DOTA-Bn-DSPE for stable (64)Cu incorporation into liposomes. PET imaging and biodistribution studies with (64)Cu-labeled liposomes indicate that accumulation in bone marrow was as high as 15.18±3.69%ID/g for 90nm liposomes and 7.01±0.92%ID/g for 140nm liposomes at 24h post-administration. In vivo biodistribution studies in tumor-bearing mice indicate that the uptake of 90nm particles is approximately 0.89±0.48%ID/g in tumor and 14.22±8.07%ID/g in bone marrow, but respective values for Doxil® like liposomes are 0.83±0.49%ID/g and 2.23±1.00%ID/g. Our results indicate that our novel PET labeled liposomes target bone marrow with very high efficiency and therefore can function as efficient bone marrow imaging agents. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Designed hydrophilic and charge mutations of the fibronectin domain: towards tailored protein biodistribution

    PubMed Central

    Hackel, Benjamin J.; Sathirachinda, Ataya; Gambhir, Sanjiv S.

    2012-01-01

    Engineered proteins are attractive affinity scaffolds for molecular imaging and drug delivery. Although exquisite binding specificity and affinity can be engineered, many proteins exhibit off-target uptake, particularly in the kidneys and liver, from physiologic effects. We quantified the ability to alter renal and hepatic uptake via hydrophilic and charge mutations. As a model protein, we used the 10th type III domain of human fibronectin, which has been engineered to bind many targets and has been validated for molecular imaging. We screened rational mutants, identified by structural and phylogenetic analyses, to yield eight mutations that collectively substantially increase protein hydrophilicity. Mutation of two parental clones yielded four domains with a range of hydrophilicity. These proteins were labeled with 64Cu, injected intravenously into nu/nu mice (n = 3–5 each) and evaluated by positron emission tomography. Renal uptake strongly correlated with hydrophilicity (Pearson's correlation coefficient = 0.97), ranging from 29 ± 11 to 100 ± 22% ID/g at 1 h. Hepatic uptake inversely correlated with hydrophilicity (Pearson's correlation coefficient = −0.92), ranging from 30 ± 7 to 3 ± 1% ID/g. Thus, renal and hepatic uptake are directly tunable through hydrophilic mutation, identifiable by structural and phylogenetic analyses. To investigate charge, we mutated acidic and basic residues in both parental clones and evaluated 64Cu-labeled mutants in nu/nu mice (n = 5–7). Selected charge removal reduced kidney signal: 78 ± 13 to 51 ± 8%ID/g (P < 0.0001) for the hydrophilic clone and 32 ± 10 to 21 ± 3 (P = 0.0005) for the hydrophobic clone. Elucidation of hydrophilicity and charge enabled modulation of background signal thereby enhancing the utility of protein scaffolds as translatable targeting agents for molecular imaging and therapy. PMID:22691700

  10. Pycup – A bifunctional, cage-like ligand for 64Cu radiolabeling

    PubMed Central

    Boros, Eszter; Rybak-Akimova, Elena; Holland, Jason P.; Rietz, Tyson; Rotile, Nicholas; Blasi, Francesco; Day, Helen; Latifi, Reza; Caravan, Peter

    2014-01-01

    In developing targeted probes for positron emission tomography (PET) based on 64Cu, stable complexation of the radiometal is key, and a flexible handle for bioconjugation is highly advantageous. Here, we present the synthesis and characterization of the chelator pycup and 4 derivatives. Pycup is a cross-bridged cyclam derivative with a pyridyl donor atom integrated into the cross-bridge resulting in a pentadentate ligand. The pycup platform provides kinetic inertness toward 64Cu de-chelation and offers versatile bioconjugation chemistry. We varied the number and type of additional donor atoms by alkylation of the remaining two secondary amines, providing three model ligands, pycup2A, pycup1A1Bn and pycup2Bn in 3–4 synthetic steps from cyclam. All model copper complexes displayed very slow decomplexation in 5 M HCl and 90 °C (t1/2: 1.5 h for pycup1A1Bn, 2.7 h for pycup2A, 20.3 h for pycup2Bn). The single crystal crystal X-ray structure of the [Cu(pycup2Bn)]2+ complex showed that the copper was coordinated in a trigonal, bi-pyramidal manner. The corresponding radiochemical complexes were at least 94% stable in rat plasma after 24 h. Biodistribution studies conducted in Balb/c mice at 2 h post-injection of 64Cu labeled pycup2A revealed low residual activity in kidney, liver and blood pool with predominantly renal clearance observed. Pycup2A was readily conjugated to a fibrin-targeted peptide and labeled with 64Cu for successful PET imaging of arterial thrombosis in a rat model, demonstrating the utility of our new chelator in vivo. PMID:24294970

  11. PET Imaging of Extracellular pH in Tumors with 64Cu- and 18F-Labeled pHLIP Peptides: A Structure–Activity Optimization Study

    PubMed Central

    2016-01-01

    pH (low) insertion peptides (pHLIP peptides) target acidic extracellular environments in vivo due to pH-dependent cellular membrane insertion. Two variants (Var3 and Var7) and wild-type (WT) pHLIP peptides have shown promise for in vivo imaging of breast cancer. Two positron emitting radionuclides (64Cu and 18F) were used to label the NOTA- and NO2A-derivatized Var3, Var7, and WT peptides for in vivo biodistribution studies in 4T1 orthotopic tumor-bearing BALB/c mice. All of the constructs were radiolabeled with 64Cu or [18F]-AlF in good yield. The in vivo biodistribution of the 12 constructs in 4T1 orthotopic allografted female BALB/c mice indicated that NO2A-cysVar3, radiolabeled with either 18F (4T1 uptake; 8.9 ± 1.7%ID/g at 4 h p.i.) or 64Cu (4T1 uptake; 8.2 ± 0.9%ID/g at 4 h p.i. and 19.2 ± 1.8% ID/g at 24 h p.i.), shows the most promise for clinical translation. Additional studies to investigate other tumor models (melanoma, prostate, and brain tumor models) indicated the universality of tumor targeting of these tracers. From this study, future clinical translation will focus on 18F- or 64Cu-labeled NO2A-cysVar3. PMID:27396694

  12. Novel (64)Cu- and (68)Ga-labeled RGD conjugates show improved PET imaging of α(ν)β(3) integrin expression and facile radiosynthesis.

    PubMed

    Dumont, Rebecca A; Deininger, Friederike; Haubner, Roland; Maecke, Helmut R; Weber, Wolfgang A; Fani, Melpomeni

    2011-08-01

    )Cu-labeled RGD peptides in patients.

  13. Controlled administration of penicillamine reduces radiation exposure in critical organs during 64Cu-ATSM internal radiotherapy: a novel strategy for liver protection.

    PubMed

    Yoshii, Yukie; Matsumoto, Hiroki; Yoshimoto, Mitsuyoshi; Furukawa, Takako; Morokoshi, Yukie; Sogawa, Chizuru; Zhang, Ming-Rong; Wakizaka, Hidekatsu; Yoshii, Hiroshi; Fujibayashi, Yasuhisa; Saga, Tsuneo

    2014-01-01

    doses to the large intestine. We developed a novel strategy to reduce radiation exposure in critical organs during (64)Cu-ATSM IRT, thus promoting its clinical applications. This method could be beneficial for other (64)Cu-labeled compounds.

  14. Detection of early stage atherosclerotic plaques using PET and CT fusion imaging targeting P-selectin in low density lipoprotein receptor-deficient mice

    SciTech Connect

    Nakamura, Ikuko; Hasegawa, Koki; Wada, Yasuhiro; Hirase, Tetsuaki; Node, Koichi; Watanabe, Yasuyoshi

    2013-03-29

    Highlights: ► P-selectin regulates leukocyte recruitment as an early stage event of atherogenesis. ► We developed an antibody-based molecular imaging probe targeting P-selectin for PET. ► This is the first report on successful PET imaging for delineation of P-selectin. ► P-selectin is a candidate target for atherosclerotic plaque imaging by clinical PET. -- Abstract: Background: Sensitive detection and qualitative analysis of atherosclerotic plaques are in high demand in cardiovascular clinical settings. The leukocyte–endothelial interaction mediated by an adhesion molecule P-selectin participates in arterial wall inflammation and atherosclerosis. Methods and results: A {sup 64}Cu-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid conjugated anti-P-selectin monoclonal antibody ({sup 64}Cu-DOTA-anti-P-selectin mAb) probe was prepared by conjugating an anti-P-selectin monoclonal antibody with DOTA followed by {sup 64}Cu labeling. Thirty-six hours prior to PET and CT fusion imaging, 3 MBq of {sup 64}Cu-DOTA-anti-P-selectin mAb was intravenously injected into low density lipoprotein receptor-deficient Ldlr-/- mice. After a 180 min PET scan, autoradiography and biodistribution of {sup 64}Cu-DOTA-anti-P-selectin monoclonal antibody was examined using excised aortas. In Ldlr-/- mice fed with a high cholesterol diet for promotion of atherosclerotic plaque development, PET and CT fusion imaging revealed selective and prominent accumulation of the probe in the aortic root. Autoradiography of aortas that demonstrated probe uptake into atherosclerotic plaques was confirmed by Oil red O staining for lipid droplets. In Ldlr-/- mice fed with a chow diet to develop mild atherosclerotic plaques, probe accumulation was barely detectable in the aortic root on PET and CT fusion imaging. Probe biodistribution in aortas was 6.6-fold higher in Ldlr-/- mice fed with a high cholesterol diet than in those fed with a normal chow diet. {sup 64}Cu-DOTA-anti-P-selectin m

  15. Evaluation of copper-64-labeled somatostatin agonists and antagonist in sstr2-transfected cell lines that are positive and negative for p53: implications for cancer therapy

    PubMed Central

    Nguyen, Kim; Parry, Jesse J.; Rogers, Buck E.; Anderson, Carolyn J.

    2011-01-01

    Objectives Radiolabeled somatostatin analogs have become important agents for molecular imaging and targeted radiotherapy of somatostatin receptor-positive tumors. Here we determine the effect of the tumor suppressor protein, p53, on trafficking 64Cu to tumor cell nuclei from DOTA vs.CB-TE2A-conjugated agonist Y3-TATE and the antagonist 64Cu-CB-TE2A-sst2-ANT in cell lines that are positive or negative for p53. Methods Receptor binding, internalization, cAMP and nuclear localization studies were performed with the SSTr2 agonists, 64Cu-CB-TE2A-Y3-TATE and 64Cu-DOTA-Y3-TATE vs. antagonist, 64Cu-CB-TE2A-sst2-ANT, in SSTr2-transfected p53 +/+ and −/− HCT116 colorectal carcinoma cells. Results The antagonist, 64Cu-CB-TE2A-sst2-ANT, bound 8-9-fold more SSTr2 binding sites than did the 64Cu-labeled agonists. 64Cu-CB-TE2A-Y3-TATE was more efficiently internalized than 64Cu-DOTA-Y3-TATE, while 64Cu-CB-TE2A-sst2-ANT showed lower, yet significant levels of internalization. CB-TE2A-Y3-TATE acted as a full agonist, inhibiting cAMP production, whereas CB-TE2A-sst2-ANT showed no inhibition of cAMP production.The 64Cu from agonists 64Cu-DOTA-Y3-TATE and 64Cu-CB-TE2A-Y3-TATE showed greater nuclear localization at 24 h in p53 +/+ vs. −/− cells; however, there was no difference in the levels of 64Cu from the antagonist based on p53 status. Surprisingly, the DOTA and CB-TE2A-conjugated agonists showed similar nuclear localization in the p53 +/+ and −/− cells, suggesting no difference in 64Cu release from these chelators in the HCT116 cell lines. Conclusion Based on thesein vitro data, the agonist 64Cu-CB-TE2A-Y3-TATE demonstrated the most promise as an agent for targeted radiotherapy in p53 positive, SSTr2-positive tumors. PMID:22056254

  16. PET Studies on P-glycoprotein function in the blood-brain barrier: how it affects uptake and binding of drugs within the CNS.

    PubMed

    Elsinga, Philip H; Hendrikse, N Harry; Bart, Joost; Vaalburg, Willem; van Waarde, Aren

    2004-01-01

    Permeability of the blood-brain barrier (BBB) is one of the factors determining the bioavailability of therapeutic drugs. The BBB only allows entry of lipophilic compounds with low molecular weights by passive diffusion. However, many lipophilic drugs show negligible brain uptake. They are substrates for transporters such as P-glycoprotein (P-gp), multidrug-resistance associated protein (MRP) and organic anion transporting polypeptides (OATPs). The action of these carrier systems results in rapid efflux of xenobiotics from the central nervous system (CNS). Classification of candidate drugs as substrates or inhibitors of such carrier proteins is of crucial importance in drug development. Positron emission tomography (PET) can play an important role in the screening process by providing in vivo information, after the putative drug has passed in vitro tests. Although radiolabeled probes for MRP and OATP function are not yet available, many radiotracers have been prepared to study P-glycoprotein function in vivo with PET. These include alkaloids ((11)C-colchicine), antineoplastic agents ((11)C-daunorubicin, (18)F-paclitaxel), modulators of L-type calcium channels ((11)C-(+/-)verapamil, (11)C-R(+)-verapamil), beta-adrenoceptor antagonists ((11)C-(S)-carazolol, (18)F-(S)-1'-fluorocarazolol, (11)C-carvedilol), serotonin 5-HT(1A) receptor antagonists ((18)F-MPPF), opioid receptor antagonists ((11)C-loperamide, (11)C-carfentanyl), and various (64)Cu-labeled copper complexes. Studies in experimental animals have indicated that it is possible to assess P-glycoprotein function in the BBB and its effect on the uptake and binding of drugs within the intact CNS, using suitable P-gp modulators labeled with positron emitters. Provided that radiopharmaceuticals (and P-gp modulators) can be developed for human use, several exciting fields of study may be explored, viz. (i) direct evaluation of the effect of modulators on the cerebral uptake of therapeutic drugs; (ii) assessment of

  17. Mechanism of Copper Uptake from Blood Plasma Ceruloplasmin by Mammalian Cells

    PubMed Central

    Ramos, Danny; Vargas, Rebecca; Gaite, Michaella; Montgomery, Aaron; Linder, Maria C.

    2016-01-01

    Ceruloplasmin, the main copper binding protein in blood plasma, has been of particular interest for its role in efflux of iron from cells, but has additional functions. Here we tested the hypothesis that it releases its copper for cell uptake by interacting with a cell surface reductase and transporters, producing apoceruloplasmin. Uptake and transepithelial transport of copper from ceruloplasmin was demonstrated with mammary epithelial cell monolayers (PMC42) with tight junctions grown in bicameral chambers, and purified human 64Cu-labeled ceruloplasmin secreted by HepG2 cells. Monolayers took up virtually all the 64Cu over 16h and secreted half into the apical (milk) fluid. This was partly inhibited by Ag(I). The 64Cu in ceruloplasmin purified from plasma of 64Cu-injected mice accumulated linearly in mouse embryonic fibroblasts (MEFs) over 3-6h. Rates were somewhat higher in Ctr1+/+ versus Ctr1-/- cells, and 3-fold lower at 2°C. The ceruloplasmin-derived 64Cu could not be removed by extensive washing or trypsin treatment, and most was recovered in the cytosol. Actual cell copper (determined by furnace atomic absorption) increased markedly upon 24h exposure to holoceruloplasmin. This was accompanied by a conversion of holo to apoceruloplasmin in the culture medium and did not occur during incubation in the absence of cells. Four different endocytosis inhibitors failed to prevent 64Cu uptake from ceruloplasmin. High concentrations of non-radioactive Cu(II)- or Fe(III)-NTA (substrates for cell surface reductases), or Cu(I)-NTA (to compete for transporter uptake) almost eliminated uptake of 64Cu from ceruloplasmin. MEFs had cell surface reductase activity and expressed Steap 2 (but not Steaps 3 and 4 or dCytB). However, six-day siRNA treatment was insufficient to reduce activity or uptake. We conclude that ceruloplasmin is a circulating copper transport protein that may interact with Steap2 on the cell surface, forming apoceruloplasmin, and Cu(I) that enters cells

  18. Positron Emission Tomography Imaging of Macaques with Tuberculosis Identifies Temporal Changes in Granuloma Glucose Metabolism and Integrin α4β1-Expressing Immune Cells.

    PubMed

    Mattila, Joshua T; Beaino, Wissam; Maiello, Pauline; Coleman, M Teresa; White, Alexander G; Scanga, Charles A; Flynn, JoAnne L; Anderson, Carolyn J

    2017-07-15

    Positron emission tomography and computed tomography imaging (PET/CT) is an increasingly valuable tool for diagnosing tuberculosis (TB). The glucose analog [(18)F]fluoro-2-deoxy-2-d-glucose ([(18)F]-FDG) is commonly used in PET/CT that is retained by metabolically active inflammatory cells in granulomas, but lacks specificity for particular cell types. A PET probe that could identify recruitment and differentiation of different cell populations in granulomas would be a useful research tool and could improve TB diagnosis and treatment. We used the Mycobacterium-antigen murine inflammation model and macaques with TB to identify [(64)Cu]-labeled CB-TE1A1P-PEG4-LLP2A ([(64)Cu]-LLP2A), a high affinity peptidomimetic ligand for very late Ag-4 (VLA-4; also called integrin α4β1) binding cells in granulomas, and compared [(64)Cu]-LLP2A with [(18)F]-FDG over the course of infection. We found that [(64)Cu]-LLP2A retention was driven by macrophages and T cells, with less contribution from neutrophils and B cells. In macaques, granulomas had higher [(64)Cu]-LLP2A uptake than uninfected tissues, and immunohistochemical analysis of granulomas with known [(64)Cu]-LLP2A uptake identified significant correlations between LLP2A signal and macrophage and T cell numbers. The same cells coexpressed integrin α4 and β1, further supporting that macrophages and T cells drive [(64)Cu]-LLP2A avidity in granulomas. Over the course of infection, granulomas and thoracic lymph nodes experienced dynamic changes in affinity for both probes, suggesting metabolic changes and cell differentiation or recruitment occurs throughout granuloma development. These results indicate [(64)Cu]-LLP2A is a PET probe for VLA-4, which when used in conjunction with [(18)F]-FDG, may be a useful tool for understanding granuloma biology in TB. Copyright © 2017 by The American Association of Immunologists, Inc.

  19. PET of c-Met in Cancer with ⁶⁴Cu-Labeled Hepatocyte Growth Factor.

    PubMed

    Luo, Haiming; Hong, Hao; Slater, Michael R; Graves, Stephen A; Shi, Sixiang; Yang, Yunan; Nickles, Robert J; Fan, Frank; Cai, Weibo

    2015-05-01

    The hepatocyte growth factor (HGF) and its receptor, c-Met, are actively involved in tumor progression and metastasis and are closely associated with a poor prognostic outcome for cancer patients. Thus, the development of PET agents that can assess c-Met expression would be extremely useful for diagnosing cancer and subsequently monitoring response to c-Met-targeted therapies. Here, we report the characterization of recombinant human HGF (rh-HGF) as a PET tracer for detection of c-Met expression in vivo. rh-HGF was expressed in human embryonic kidney 293 cells and purified by nickel-nitrilotriacetic acid affinity chromatography. The concentrated rh-HGF was conjugated to 2-S-(4-isothiocyanatobenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid and labeled with (64)Cu. c-Met binding evaluation by flow cytometry was performed on both U87MG and MDA-MB-231 cell lines, which have a high level and a low level, respectively, of c-Met. PET imaging and biodistribution studies were performed on nude mice bearing U87MG and MDA-MB-231 xenografted tumors. The rh-HGF expression yield was 150-200 μg of protein per 5 × 10(6) cells after a 48-h transfection, with purity of approximately 85%-90%. Flow cytometry examination confirmed that rh-HGF had a strong and specific capacity to bind to c-Met. After (64)Cu labeling, PET imaging revealed specific and prominent uptake of (64)Cu-NOTA-rh-HGF in c-Met-positive U87MG tumors (percentage injected dose per gram, 6.8 ± 1.8 at 9 h after injection) and significantly lower uptake in c-Met-negative MDA-MB-231 tumors (percentage injected dose per gram, 1.8 ± 0.6 at 9 h after injection). The fact that sonication-denatured rh-HGF had significantly lower uptake in U87MG tumors, along with histology analysis, confirmed the c-Met specificity of (64)Cu-NOTA-rh-HGF. This study provided initial evidence that (64)Cu-NOTA-rh-HGF visualizes c-Met expression in vivo, an application that may prove useful for c-Met-targeted cancer therapy. © 2015 by the

  20. MicroPET/CT imaging of patient-derived pancreatic cancer xenografts implanted subcutaneously or orthotopically in NOD-scid mice using (64)Cu-NOTA-panitumumab F(ab')2 fragments.

    PubMed

    Boyle, Amanda J; Cao, Ping-Jiang; Hedley, David W; Sidhu, Sachdev S; Winnik, Mitchell A; Reilly, Raymond M

    2015-02-01

    Our objective was to study microPET/CT imaging of patient-derived pancreatic cancer xenografts in NOD-scid mice using F(ab')2 fragments of the fully-human anti-EGFR monoclonal antibody, panitumumab (Vectibix) labeled with (64)Cu. More than 90% of pancreatic cancers are EGFR-positive. F(ab')2 fragments were produced by proteolytic digestion of panitumumab IgG or non-specific human IgG, purified by ultrafiltration then modified with NOTA chelators for complexing (64)Cu. Panitumumab IgG and Fab fragments were similarly labeled with (64)Cu. EGFR immunoreactivity was determined in competition and direct (saturation) cell binding assays. The biodistribution of (64)Cu-labeled panitumumab IgG, F(ab')2 and Fab was compared in non-tumor-bearing Balb/c mice. MicroPET/CT and biodistribution studies were performed in NOD-scid mice engrafted subcutaneously (s.c.) or orthotopically with patient-derived OCIP23 pancreatic tumors, or in NOD-scid with s.c. PANC-1 human pancreatic cancer xenografts. Panitumumab F(ab')2 fragments were produced in high purity (>90%), derivitized with 3.2±0.7 NOTA/F(ab')2, and labeled with (64)Cu (0.3-3.6MBq/μg). The binding of (64)Cu-NOTA-panitumumab F(ab')2 to OCIP23 or PANC-1 cells was decreased significantly by an excess of panitumumab IgG. The Kd for binding of (64)Cu-NOTA-panitumumab F(ab')2 to EGFR on PANC-1 cells was 0.14±0.05nmol/L. F(ab')2 fragments exhibited more suitable normal tissue distribution for tumor imaging with (64)Cu than panitumumab IgG or Fab. Tumor uptake at 48h post injection (p.i.) of (64)Cu-NOTA-panitumumab F(ab')2 was 12.0±0.9% injected dose/g (ID/g) in s.c. and 11.8±0.9% ID/g in orthotopic OCIP23 tumors vs. 6.1±1.1% ID/g in s.c. PANC-1 xenografts. Tumor/Blood (T/B) ratios were 5:1 to 9:1 for OCIP23 and 2.4:1 for PANC-1 tumors. Tumor uptake of (64)Cu-NOTA-non-specific F(ab')2 in OCIP23 xenografts was 5-fold lower than (64)Cu-panitumumab F(ab')2. All tumor xenografts were clearly imaged by microPET/CT at 24 or 48h p

  1. In Vitro and In Vivo Evaluation of 64Cu-Radiolabeled KCCYSL Peptides for Targeting Epidermal Growth Factor Receptor-2 in Breast Carcinomas

    PubMed Central

    Kumar, Senthil R.; Gallazzi, Fabio A.; Ferdani, Riccardo; Anderson, Carolyn J.; Quinn, Thomas P.

    2010-01-01

    pharmacokinetic properties of the 64Cu-labeled GSG-KCCYSL peptide, which enables the selection of a suitable peptide homolog as a PET imaging agent for EGFR-2 expressing breast carcinomas. PMID:21204764

  2. 68Ga-labeling and in vivo evaluation of a uPAR binding DOTA- and NODAGA-conjugated peptide for PET imaging of invasive cancers.

    PubMed

    Persson, Morten; Madsen, Jacob; Østergaard, Søren; Ploug, Michael; Kjaer, Andreas

    2012-05-01

    -NODAGA-AE105-NH(2) 60 min postinjection. The use of (68)Ga-DOTA-AE105-NH(2) and (68)Ga-NODAGA-AE105-NH(2) as the first gallium-68 labeled uPAR radiotracers for noninvasive PET imaging is reported, which combine versatility with good imaging properties. These new tracers thus constitute an interesting alternative to the (64)Cu-labeled version ((64)Cu-DOTA-AE105 and 64Cu-DOTA-AE105-NH(2)) for detecting uPAR expression in tumor tissue. In our hands, the fractionated elution approach was superior for labeling of peptides, and (68)Ga-NODAGA-AE105-NH(2) is the favored tracer as it provides the highest tumor-to-background ratio. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. Radio-photothermal therapy mediated by a single compartment nanoplatform depletes tumor initiating cells and reduces lung metastasis in the orthotopic 4T1 breast tumor model

    NASA Astrophysics Data System (ADS)

    Zhou, Min; Zhao, Jun; Tian, Mei; Song, Shaoli; Zhang, Rui; Gupta, Sanjay; Tan, Dongfeng; Shen, Haifa; Ferrari, Mauro; Li, Chun

    2015-11-01

    breast tumor metastasis through eradication of TICs. Positron electron tomography (PET) imaging and biodistribution studies showed that more than 90% of [64Cu]CuS NPs was retained in subcutaneously grown BT474 breast tumor 24 h after intratumoral (i.t.) injection, indicating the NPs are suitable for the combination therapy. Combined RT/PTT therapy resulted in significant tumor growth delay in the subcutaneous BT474 breast cancer model. Moreover, RT/PTT treatment significantly prolonged the survival of mice bearing orthotopic 4T1 breast tumors compared to no treatment, RT alone, or PTT alone. The RT/PTT combination therapy significantly reduced the number of tumor nodules in the lung and the formation of tumor mammospheres from treated 4T1 tumors. No obvious side effects of the CuS NPs were noted in the treated mice in a pilot toxicity study. Taken together, our data support the feasibility of a therapeutic approach for the suppression of tumor metastasis through localized RT/PTT therapy. Electronic supplementary information (ESI) available: Details of methods used for radiolabeling efficiency and stability of 64Cu-labeled CuS NPs. See DOI: 10.1039/c5nr04587h

  4. (64)Cu- and (68)Ga-Based PET Imaging of Folate Receptor-Positive Tumors: Development and Evaluation of an Albumin-Binding NODAGA-Folate.

    PubMed

    Farkas, Renáta; Siwowska, Klaudia; Ametamey, Simon M; Schibli, Roger; van der Meulen, Nicholas P; Müller, Cristina

    2016-06-06

    A number of folate-based radioconjugates have been synthesized and evaluated for nuclear imaging purposes of folate receptor (FR)-positive tumors and potential therapeutic application. A common shortcoming of radiofolates is, however, a significant accumulation of radioactivity in the kidneys. This situation has been faced by modifying the folate conjugate with an albumin-binding entity to increase the circulation time of the radiofolate, which led to significantly improved tumor-to-kidney ratios. The aim of this study was to develop an albumin-binding folate conjugate with a NODAGA-chelator (rf42) for labeling with (64)Cu and (68)Ga, allowing application for PET imaging. The folate conjugate rf42 was synthesized in 8 steps, with an overall yield of 5%. Radiolabeling with (64)Cu and (68)Ga was carried out at room temperature within 10 min resulting in (64)Cu-rf42 and (68)Ga-rf42 with >95% radiochemical purity. (64)Cu-rf42 and (68)Ga-rf42 were stable (>95% intact) in phosphate-buffered saline over more than 4 half-lives of the corresponding radionuclide. In vitro, the plasma protein-bound fraction of (64)Cu-rf42 and (68)Ga-rf42 was determined to be >96%. Cell experiments proved FR-specific uptake of both radiofolates, as it was reduced to <1% when KB tumor cells were coincubated with excess folic acid. In vivo, high accumulation of (64)Cu-rf42 and (68)Ga-rf42 was found in KB tumors of mice (14.52 ± 0.99% IA/g and 11.92 ± 1.68% IA/g, respectively) at 4 h after injection. The tumor-to-kidney ratios were in the range of 0.43-0.55 over the first 4 h of investigation. At later time points (up to 72 h p.i. of (64)Cu-rf42) the tumor-to-kidney ratio increased to 0.73. High-quality PET/CT images were obtained 2 h after injection of (64)Cu-rf42 and (68)Ga-rf42, respectively, allowing distinct visualization of tumors and kidneys. Comparison of PET/CT images obtained with (64)Cu-rf42 and a (64)Cu-labeled DOTA-folate conjugate (cm10) clearly proved the superiority of NODAGA