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Badier L, Quelven I. Zirconium 89 and Copper 64 for ImmunoPET: From Antibody Bioconjugation and Radiolabeling to Molecular Imaging. Pharmaceutics 2024; 16:882. [PMID: 39065579 PMCID: PMC11279968 DOI: 10.3390/pharmaceutics16070882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 06/15/2024] [Accepted: 06/24/2024] [Indexed: 07/28/2024] Open
Abstract
Immunotherapy has transformed cancer treatment. Nevertheless, given the heterogeneity of clinical efficacy, the multiplicity of treatment options available and the possibility of serious adverse effects, selecting the most effective treatment has become the greatest challenge. Molecular imaging offers an attractive way for this purpose. ImmunoPET provides specific imaging with positron emission tomography (PET) using monoclonal antibodies (mAb) or its fragments as vector. By combining the high targeting specificity of mAb and the sensitivity of PET technique, immunoPET could noninvasively and dynamically reveal tumor antigens expression and provide theranostic tools of several types of malignancies. Because of their slow kinetics, mAbs require radioelements defined by a consistent half-life. Zirconium 89 (89Zr) and Copper 64 (64Cu) are radiometals with half-lives suitable for mAb labeling. Radiolabeling with a radiometal requires the prior use of a bifunctional chelate agent (BFCA) to functionalize mAb for radiometal chelation, in a second step. There are a number of BFCA available and much research is focused on antibody functionalization techniques or on developing the optimum chelating agent depending the selected radiometal. In this manuscript, we present a critical account of radiochemical techniques with radionuclides 89Zr and 64Cu and their applications in preclinical and clinical immuno-PET imaging.
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Affiliation(s)
| | - Isabelle Quelven
- Toulouse NeuroImaging Center (ToNIC), INSERM/UPS UMR 1214, University Hospital of Toulouse-Purpan, CEDEX 3, 31024 Toulouse, France;
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2
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Tunçel A, Maschauer S, Prante O, Yurt F. In Vitro Assessment of 177Lu-Labeled Trastuzumab-Targeted Mesoporous Carbon@Silica Nanostructure for the Treatment of HER2-Positive Breast Cancer. Pharmaceuticals (Basel) 2024; 17:732. [PMID: 38931400 PMCID: PMC11206869 DOI: 10.3390/ph17060732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 05/27/2024] [Accepted: 06/01/2024] [Indexed: 06/28/2024] Open
Abstract
This study assessed the effectiveness of a trastuzumab-targeted 177Lu-labeled mesoporous Carbon@Silica nanostructure (DOTA@TRA/MC@Si) for HER2-positive breast cancer treatment, focusing on its uptake, internalization, and efflux in breast cancer cells. The synthesized PEI-MC@Si nanocomposite was reacted with DOTA-NHS-ester, confirmed by the Arsenazo(III) assay. Following this, TRA was conjugated to the DOTA@PEI-MC@Si for targeting. DOTA@PEI-MC@Si and DOTA@TRA/MC@Si nanocomposites were labeled with 177Lu, and their efficacy was evaluated through in vitro radiolabeling experiments. According to the results, the DOTA@TRA/MC@Si nanocomposite was successfully labeled with 177Lu, yielding a radiochemical yield of 93.0 ± 2.4%. In vitro studies revealed a higher uptake of the [177Lu]Lu-DOTA@TRA/MC@Si nanocomposite in HER2-positive SK-BR-3 cells (44.0 ± 4.6% after 24 h) compared to MDA-MB-231 cells (21.0 ± 2.3%). The IC50 values for TRA-dependent uptake in the SK-BR-3 and BT-474 cells were 0.9 µM and 1.3 µM, respectively, indicating affinity toward HER-2 receptor-expressing cells. The lipophilic distribution coefficients of the radiolabeled nanocomposites were determined to be 1.7 ± 0.3 for [177Lu]Lu-DOTA@TRA/MC@Si and 1.5 ± 0.2 for [177Lu]Lu-DOTA@PEI-MC@Si, suggesting sufficient passive transport through the cell membrane and increased accumulation in target tissues. The [177Lu]Lu-DOTA@TRA/MC@Si nanocomposite showed an uptake into HER2-positive cell lines, marking a valuable step toward the development of a nanoparticle-based therapeutic agent for an improved treatment strategy for HER2-positive breast cancer.
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Affiliation(s)
- Ayça Tunçel
- Department of Nuclear Applications, Institute of Nuclear Science, Ege University, Bornova 35100, Turkey;
| | - Simone Maschauer
- Department of Nuclear Medicine, Molecular Imaging and Radiochemistry, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Ulmenweg 18, D-91054 Erlangen, Germany;
| | - Olaf Prante
- Department of Nuclear Medicine, Molecular Imaging and Radiochemistry, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Ulmenweg 18, D-91054 Erlangen, Germany;
| | - Fatma Yurt
- Department of Nuclear Applications, Institute of Nuclear Science, Ege University, Bornova 35100, Turkey;
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3
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Amirdhanayagam J, Guleria M, Sharma R, Kumar N, Mukherjee A, Das T. Formulation of patient dose of [ 177Lu]Lu-Trastuzumab using in-house developed freeze-dried kit: A path forward for clinical translation. J Labelled Comp Radiopharm 2024; 67:131-144. [PMID: 38342496 DOI: 10.1002/jlcr.4086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 01/15/2024] [Accepted: 01/16/2024] [Indexed: 02/13/2024]
Abstract
Trastuzumab is a US-FDA-approved humanized monoclonal antibody used for the treatment of human epidermal growth factor receptor 2 (HER2)-positive breast cancer. The aim of the present work is to optimize a freeze-dried formulation of DOTA-Trastuzumab conjugate for the preparation of patient doses of [177Lu]Lu-Trastuzumab for radioimmunotherapy of breast cancer. The formulation of [177Lu]Lu-Trastuzumab usually takes a long time, and thus, such a process is not suitable for the routine preparation of this agent in hospital radiopharmacies. To circumvent this, a pre-synthesized DOTA-Trastuzumab conjugate as a freeze-dried formulation is proposed. In the present work, DOTA-Trastuzumab conjugate was subjected to a freeze-drying process after the addition of optimized amounts of radioprotectant and cryoprotectant. [177Lu]Lu-DOTA-Trastuzumab was prepared by incubating the lyophilized powder of the kit vial with medium-specific activity 177LuCl3. The final radiochemical purity of [177Lu]Lu-DOTA-Trastuzumab, prepared using freeze-dried kit, was determined to be >95%. To ascertain the reproducibility of the procedure, six consecutive batches of the freeze-dried formulation were prepared, radiolabeled, and evaluated by carrying out both in vitro and ex vivo studies. The consistency of the results of all the six consecutive batches confirmed the robustness and utility of the in-house optimized freeze-dried formulation for the preparation of patient doses of [177Lu]Lu-Trastuzumab at hospital radiopharmacies.
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Affiliation(s)
| | - Mohini Guleria
- Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai, India
- Homi Bhabha National Institute, Mumbai, India
| | - Rohit Sharma
- Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai, India
- Homi Bhabha National Institute, Mumbai, India
| | - Naveen Kumar
- Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai, India
- Homi Bhabha National Institute, Mumbai, India
| | - Archana Mukherjee
- Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai, India
- Homi Bhabha National Institute, Mumbai, India
| | - Tapas Das
- Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai, India
- Homi Bhabha National Institute, Mumbai, India
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4
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Hull A, Hsieh W, Borysenko A, Tieu W, Bartholomeusz D, Bezak E. Development of [ 225Ac]Ac-DOTA-C595 as radioimmunotherapy of pancreatic cancer: in vitro evaluation, dosimetric assessment and detector calibration. EJNMMI Radiopharm Chem 2023; 8:22. [PMID: 37679594 PMCID: PMC10484829 DOI: 10.1186/s41181-023-00209-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 08/28/2023] [Indexed: 09/09/2023] Open
Abstract
BACKGROUND Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy which may benefit from radioimmunotherapy. Previously, [177Lu]Lu-DOTA-C595 has been developed as a beta-emitting radioimmunoconjugate to target cancer-specific mucin 1 epitopes (MUC1-CE) overexpressed on PDAC. However, the therapeutic effect may be enhanced by using an alpha-emitting radionuclide such as Actinium-225 (Ac-225). The short range and high linear energy transfer of alpha particles provides dense cellular damage and can overcome typical barriers related to PDAC treatment such as hypoxia. Despite the added cytotoxicity of alpha-emitters, their clinical implementation can be complicated by their complex decay chains, recoil energy and short-range impeding radiation detection. In this study, we developed and evaluated [225Ac]Ac-DOTA-C595 as an alpha-emitting radioimmunotherapy against PDAC using a series of in vitro experiments and conducted a preliminary dosimetric assessment and cross-calibration of detectors for the clinical implementation of Ac-225. RESULTS Cell binding and internalisation of [225Ac]Ac-DOTA-C595 was rapid and greatest in cells with strong MUC1-CE expression. Over 99% of PDAC cells had positive yH2AX expression within 1 h of [225Ac]Ac-DOTA-C595 exposure, suggesting a high level of DNA damage. Clonogenic assays further illustrated the cytotoxicity of [225Ac]Ac-DOTA-C595 in a concentration-dependent manner. At low concentrations of [225Ac]Ac-DOTA-C595, cells with strong MUC1-CE expression had lower cell survival than cells with weak MUC1-CE expression, yet survival was similar between cell lines at high concentrations irrespective of MUC1-CE expression. A dosimetric assessment was performed to estimate the dose-rate of 1 kBq of [225Ac]Ac-DOTA-C595 with consideration to alpha particles. Total absorption of 1 kBq of Ac-225 was estimated to provide a dose rate of 17.5 mGy/h, confirmed via both detector measurements and calculations. CONCLUSION [225Ac]Ac-DOTA-C595 was shown to target and induce a therapeutic effect in MUC1-CE expressing PDAC cells.
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Affiliation(s)
- Ashleigh Hull
- Allied Health and Human Performance Academic Unit, University of South Australia, City East Campus, Cnr North Tce and Frome Road, Adelaide, SA, 5001, Australia.
- Department of PET, Nuclear Medicine & Bone Densitometry, Royal Adelaide Hospital, SA Medical Imaging, Adelaide, SA, 5000, Australia.
| | - William Hsieh
- Allied Health and Human Performance Academic Unit, University of South Australia, City East Campus, Cnr North Tce and Frome Road, Adelaide, SA, 5001, Australia
- Department of PET, Nuclear Medicine & Bone Densitometry, Royal Adelaide Hospital, SA Medical Imaging, Adelaide, SA, 5000, Australia
| | - Artem Borysenko
- Radiation Protection Branch, South Australian Environment Protection Authority, Adelaide, SA, 5000, Australia
| | - William Tieu
- School of Physical Sciences, The University of Adelaide, Adelaide, SA, 5000, Australia
| | - Dylan Bartholomeusz
- Department of PET, Nuclear Medicine & Bone Densitometry, Royal Adelaide Hospital, SA Medical Imaging, Adelaide, SA, 5000, Australia
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5000, Australia
| | - Eva Bezak
- Allied Health and Human Performance Academic Unit, University of South Australia, City East Campus, Cnr North Tce and Frome Road, Adelaide, SA, 5001, Australia
- School of Physical Sciences, The University of Adelaide, Adelaide, SA, 5000, Australia
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5
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Hull A, Hsieh W, Tieu W, Bartholomeusz D, Li Y, Bezak E. In vitro characterisation of [ 177Lu]Lu-DOTA-C595 as a novel radioimmunotherapy for MUC1-CE positive pancreatic cancer. EJNMMI Radiopharm Chem 2023; 8:18. [PMID: 37578571 PMCID: PMC10425306 DOI: 10.1186/s41181-023-00204-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 08/02/2023] [Indexed: 08/15/2023] Open
Abstract
BACKGROUND Pancreatic ductal adenocarcinoma (PDAC) continues to be a malignancy with an unmet clinical demand. Development of radioimmunoconjugates which target cancer-specific receptors provides an opportunity for radioimmunotherapy of both metastatic and primary PDAC. In this study, we characterised the in vitro behaviour of a novel beta-emitting radioimmunoconjugate [177Lu]Lu-DOTA-C595 as a therapeutic agent against PDAC. [177Lu]Lu-DOTA-C595 is designed to target cancer-specific mucin 1 epitopes (MUC1-CE) overexpressed on most epithelial cancers, including PDAC. RESULTS A series of in vitro experiments were performed on PDAC cell lines (PANC-1, CAPAN-1, BxPC-3 and AsPC-1) exhibiting strong to weak MUC1-CE expression. [177Lu]Lu-DOTA-C595 bound to all cell lines relative to their expression of MUC1-CE. [177Lu]Lu-DOTA-C595 was also rapidly internalised across all cell lines, with a maximum of 75.4% of activity internalised within the PANC-1 cell line at 48 h. The expression of γH2AX foci and clonogenic survival of PANC-1 and AsPC-1 cell lines after exposure to [177Lu]Lu-DOTA-C595 were used to quantify the in vitro cytotoxicity of [177Lu]Lu-DOTA-C595. At 1 h post treatment, the expression of γH2AX foci exceeded 97% in both cell lines. The expression of γH2AX foci continued to increase in PANC-1 cells at 24 h, although expression reduced in AsPC-1. Clonogenic assays showed a high level of cell kill induced by [177Lu]Lu-DOTA-C595. CONCLUSION [177Lu]Lu-DOTA-C595 has favourable in vitro characteristics to target and treat MUC1-CE positive PDAC. Further investigations to characterise the in vivo effects and potential value of [177Lu]Lu-DOTA-C595 in other MUC1-CE expressing malignancies such as lung, ovarian and colorectal adenocarcinoma are warranted.
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Affiliation(s)
- Ashleigh Hull
- Allied Health and Human Performance Academic Unit, University of South Australia, City East Campus, Cnr North Tce and Frome Road, Adelaide, SA, 5001, Australia.
- Department of PET, Nuclear Medicine and Bone Densitometry, Royal Adelaide Hospital, SA Medical Imaging, Adelaide, SA, 5000, Australia.
| | - William Hsieh
- Allied Health and Human Performance Academic Unit, University of South Australia, City East Campus, Cnr North Tce and Frome Road, Adelaide, SA, 5001, Australia
- Department of PET, Nuclear Medicine and Bone Densitometry, Royal Adelaide Hospital, SA Medical Imaging, Adelaide, SA, 5000, Australia
| | - William Tieu
- School of Physical Sciences, The University of Adelaide, Adelaide, SA, 5000, Australia
| | - Dylan Bartholomeusz
- Department of PET, Nuclear Medicine and Bone Densitometry, Royal Adelaide Hospital, SA Medical Imaging, Adelaide, SA, 5000, Australia
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5000, Australia
| | - Yanrui Li
- Allied Health and Human Performance Academic Unit, University of South Australia, City East Campus, Cnr North Tce and Frome Road, Adelaide, SA, 5001, Australia
| | - Eva Bezak
- Allied Health and Human Performance Academic Unit, University of South Australia, City East Campus, Cnr North Tce and Frome Road, Adelaide, SA, 5001, Australia
- School of Physical Sciences, The University of Adelaide, Adelaide, SA, 5000, Australia
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Chen LA, Yu YH, Tian WT, Lin WC, Grauffel C, Wu CY, Chen CL, Lim C, Chu HM, Chang TW, Peng CJ. Site-specific Conjugation of 6 DOTA Chelators to a CA19-9-targeting scFv-Fc Antibody for Imaging and Therapy. J Med Chem 2023; 66:10604-10616. [PMID: 37462154 PMCID: PMC10424180 DOI: 10.1021/acs.jmedchem.3c00753] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Indexed: 08/11/2023]
Abstract
Antibodies conjugated with diagnostic/therapeutic radionuclides are attractive options for inoperable cancers lacking accurate imaging methods and effective therapeutics, such as pancreatic cancer. Hence, we have produced an antibody radionuclide conjugate termed TE-1132 comprising a α-CA19-9 scFv-Fc that is site-specifically conjugated at each C-terminus to 3 DOTA chelators via a cysteine-containing peptide linker. The smaller scFv-Fc size facilitates diffusivity within solid tumors, whereas the chelator-to-antibody ratio of six enabled 177Lu-radiolabeled TE-1132 to exhibit high radioactivity up to 520 MBq/nmol. In mice bearing BxPC3 tumors, immuno-SPECT/CT imaging of [111In]In-TE-1132 and the biodistribution of [177Lu]Lu-TE-1132 showed selective tumor accumulation. Single and multiple doses of [177Lu]Lu-TE-1132 effectively inhibited the BxPC3 tumor growth and prolonged the survival of mice with no irreversible body weight loss or hematopoietic damage. The adequate pharmacokinetic parameters, prominent tumor accumulation, and efficacy with good safety in mice encourage the further investigation of theranostic TE-1132 for treating pancreatic cancer.
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Affiliation(s)
- Li-An Chen
- Immunwork,
Inc., Academia Rd., Sec.
1, Nangang, Taipei 11571, Taiwan
| | - Yueh-Hsiang Yu
- Immunwork,
Inc., Academia Rd., Sec.
1, Nangang, Taipei 11571, Taiwan
| | - Wei-Ting Tian
- Immunwork,
Inc., Academia Rd., Sec.
1, Nangang, Taipei 11571, Taiwan
| | - Wei-Chen Lin
- Immunwork,
Inc., Academia Rd., Sec.
1, Nangang, Taipei 11571, Taiwan
| | - Cédric Grauffel
- Immunwork,
Inc., Academia Rd., Sec.
1, Nangang, Taipei 11571, Taiwan
| | - Chun-Yi Wu
- Department
of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, Beitou, Taipei 112, Taiwan
| | - Chuan-Lin Chen
- Department
of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, Beitou, Taipei 112, Taiwan
| | - Carmay Lim
- Institute
of Biomedical Sciences, Academia Sinica, Academia Road, Taipei 115, Taiwan
| | - Hsing-Mao Chu
- Immunwork,
Inc., Academia Rd., Sec.
1, Nangang, Taipei 11571, Taiwan
| | - Tse-Wen Chang
- Immunwork,
Inc., Academia Rd., Sec.
1, Nangang, Taipei 11571, Taiwan
| | - Chi-Jiun Peng
- Immunwork,
Inc., Academia Rd., Sec.
1, Nangang, Taipei 11571, Taiwan
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7
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Hull A, Li Y, Bartholomeusz D, Hsieh W, Tieu W, Pukala TL, Staudacher AH, Bezak E. Preliminary Development and Testing of C595 Radioimmunoconjugates for Targeting MUC1 Cancer Epitopes in Pancreatic Ductal Adenocarcinoma. Cells 2022; 11:cells11192983. [PMID: 36230945 PMCID: PMC9563759 DOI: 10.3390/cells11192983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 09/23/2022] [Indexed: 11/16/2022] Open
Abstract
Mucin 1 is a transmembrane glycoprotein which overexpresses cancer-specific epitopes (MUC1-CE) on pancreatic ductal adenocarcinoma (PDAC) cells. As PDAC is a low survival and highly aggressive malignancy, developing radioimmunoconjugates capable of targeting MUC1-CE could lead to improvements in PDAC outcomes. The aim of this study was to develop and perform preliminary testing of diagnostic and therapeutic radioimmunoconjugates for PDAC using an anti-MUC1 antibody, C595. Firstly, p-SCN-Bn-DOTA was conjugated to the C595 antibody to form a DOTA-C595 immunoconjugate. The stability and binding affinity of the DOTA-C595 conjugate was evaluated using mass spectrometry and ELISA. DOTA-C595 was radiolabelled to Copper-64, Lutetium-177, Gallium-68 and Technetium-99m to form novel radioimmunoconjugates. Cell binding assays were performed in PANC-1 (strong MUC1-CE expression) and AsPC-1 (weak MUC1-CE expression) cell lines using 64Cu-DOTA-C595 and 177Lu-DOTA-C595. An optimal molar ratio of 4:1 DOTA groups per C595 molecule was obtained from the conjugation process. DOTA-C595 labelled to Copper-64, Lutetium-177, and Technetium-99m with high efficiency, although the Gallium-68 labelling was low. 177Lu-DOTA-C595 demonstrated high cellular binding to the PANC-1 cell lines which was significantly greater than AsPC-1 binding at concentrations exceeding 100 nM (p < 0.05). 64Cu-DOTA-C595 showed similar binding to the PANC-1 and AsPC-1 cells with no significant differences observed between cell lines (p > 0.05). The high cellular binding of 177Lu-DOTA-C595 to MUC1-CE positive cell lines suggests promise as a therapeutic radioimmunoconjugate against PDAC while further work is required to harness the potential of 64Cu-DOTA-C595 as a diagnostic radioimmunoconjugate.
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Affiliation(s)
- Ashleigh Hull
- Allied Health and Human Performance Academic Unit, Cancer Research Institute, University of South Australia, Adelaide, SA 5001, Australia
- Department of PET, Nuclear Medicine & Bone Densitometry, Royal Adelaide Hospital, SA Medical Imaging, Adelaide, SA 5000, Australia
- Correspondence:
| | - Yanrui Li
- Allied Health and Human Performance Academic Unit, Cancer Research Institute, University of South Australia, Adelaide, SA 5001, Australia
| | - Dylan Bartholomeusz
- Department of PET, Nuclear Medicine & Bone Densitometry, Royal Adelaide Hospital, SA Medical Imaging, Adelaide, SA 5000, Australia
- Adelaide Medical School, The University of Adelaide, Adelaide, SA 5000, Australia
| | - William Hsieh
- Allied Health and Human Performance Academic Unit, Cancer Research Institute, University of South Australia, Adelaide, SA 5001, Australia
- Department of PET, Nuclear Medicine & Bone Densitometry, Royal Adelaide Hospital, SA Medical Imaging, Adelaide, SA 5000, Australia
| | - William Tieu
- Molecular Imaging and Therapy Research Unit, South Australian Health and Medical Research Institute, Adelaide, SA 5000, Australia
- School of Physical Sciences, The University of Adelaide, Adelaide, SA 5000, Australia
| | - Tara L. Pukala
- School of Physical Sciences, The University of Adelaide, Adelaide, SA 5000, Australia
| | - Alexander H. Staudacher
- Adelaide Medical School, The University of Adelaide, Adelaide, SA 5000, Australia
- Translational Oncology Laboratory, Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA 5000, Australia
| | - Eva Bezak
- Allied Health and Human Performance Academic Unit, Cancer Research Institute, University of South Australia, Adelaide, SA 5001, Australia
- School of Physical Sciences, The University of Adelaide, Adelaide, SA 5000, Australia
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Kadassery KJ, King AP, Fayn S, Baidoo KE, MacMillan SN, Escorcia FE, Wilson JJ. H 2BZmacropa-NCS: A Bifunctional Chelator for Actinium-225 Targeted Alpha Therapy. Bioconjug Chem 2022; 33:1222-1231. [PMID: 35670495 PMCID: PMC9362842 DOI: 10.1021/acs.bioconjchem.2c00190] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Actinium-225 (225Ac) is one of the most promising radionuclides for targeted alpha therapy (TAT). With a half-life of 9.92 days and a decay chain that emits four high-energy α particles, 225Ac is well-suited for TAT when conjugated to macromolecular targeting vectors that exhibit extended in vivo circulation times. The implementation of 225Ac in these targeted constructs, however, requires a suitable chelator that can bind and retain this radionuclide in vivo. Previous work has demonstrated the suitability of a diaza-18-crown-6 macrocyclic chelator H2macropa for this application. Building upon these prior efforts, in this study, two rigid variants of H2macropa, which contain either one (H2BZmacropa) or two (H2BZ2macropa) benzene rings within the macrocyclic core, were synthesized and investigated for their potential use for 225Ac TAT. The coordination chemistry of these ligands with La3+, used as a nonradioactive model for Ac3+, was carried out. Both NMR spectroscopic and X-ray crystallographic studies of the La3+ complexes of these ligands revealed similar structural features to those found for the related complex of H2macropa. Thermodynamic stability constants of the La3+ complexes, however, were found to be 1 and 2 orders of magnitude lower than those of H2macropa for H2BZmacropa and H2BZ2macropa, respectively. The decrease in thermodynamic stability was rationalized via the use of density functional theory calculations. 225Ac radiolabeling and serum stability studies with H2BZmacropa showed that this chelator compares favorably with H2macropa. Based on these promising results, a bifunctional version of this chelator, H2BZmacropa-NCS, was synthesized and conjugated to the antibody codrituzumab (GC33), which targets the liver cancer biomarker glypican-3 (GPC3). The resulting GC33-BZmacropa conjugate and an analogous GC33-macropa conjugate were evaluated for their 225Ac radiolabeling efficiencies, antigen-binding affinities, and in vivo biodistribution in HepG2 liver cancer tumor-bearing mice. Although both conjugates were comparably effective in their radiolabeling efficiencies, [225Ac]Ac-GC33-BZmacropa showed slightly poorer serum stability and biodistribution than [225Ac]Ac-GC33-macropa. Together, these results establish H2BZmacropa-NCS as a new bifunctional chelator for the preparation of 225Ac radiopharmaceuticals.
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Affiliation(s)
- Karthika J. Kadassery
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - A. Paden King
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Stanley Fayn
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Kwamena E. Baidoo
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Samantha N. MacMillan
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Freddy E. Escorcia
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Justin J. Wilson
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
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9
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Functional in vitro assessment of modified antibodies: Impact of label on protein properties. PLoS One 2021; 16:e0257342. [PMID: 34529712 PMCID: PMC8445452 DOI: 10.1371/journal.pone.0257342] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 08/30/2021] [Indexed: 12/16/2022] Open
Abstract
Labelling of therapeutic antibodies with radionuclides or fluorophores is routinely used to study their pharmacokinetic properties. A critical assumption in utilizing labelled therapeutic antibodies is that the label has no unfavourable effects on antibody charge, hydrophobicity, or receptor affinity. Ideally, the labelled protein should not have any significant deviations from the physiological properties of the original molecule. This article describes an established quality in vitro assessment workflow for labelled antibodies that ensures better prediction of changes in antibody pharmacokinetic (PK) properties after modifications. This analysis package considers degradation and aggregation analysis by size-exclusion chromatography, changes in neonatal-Fc-receptor (FcRn) affinity, and heparin interaction. FcRn binding is important for antibody recycling and half-life extension, whereas heparin affinity provides estimates on the rate of endocytosis through unspecific cell surface binding. Additionally, mass spectrometric analysis to determine the degree of labelling (DoL) completes the package and the combined analysis data allow to predict the label contribution to the PK properties of the modified antibody. This analytical strategy for labelling 11 IgGs has been investigated using 2 different IgG1 constructs and applying 7 different types of labels. Each labelling resulted in a change in the physicochemical properties of the protein. Not only can the DoL of modified IgGs lead to a change in protein properties, but the type of label also can. Furthermore, it was demonstrated that the labelling process can also influence the behaviour of labelled mAbs. An identical label on different constructs of IgG1 can cause different affinities for FcRn and heparin. Considering the assessment data, only 6 of the 11 modified antibodies from this study can be recommended for subsequent experiments. In conclusion, a suitability assessment of labelled antibodies prior to any pharmacokinetic studies is essential to reduce cost, allocate resources and reduce the number of animal experiments during pre-clinical drug development.
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10
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Impact of DOTA Conjugation on Pharmacokinetics and Immunoreactivity of [ 177Lu]Lu-1C1m-Fc, an Anti TEM-1 Fusion Protein Antibody in a TEM-1 Positive Tumor Mouse Model. Pharmaceutics 2021; 13:pharmaceutics13010096. [PMID: 33451158 PMCID: PMC7828678 DOI: 10.3390/pharmaceutics13010096] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 12/30/2020] [Accepted: 01/06/2021] [Indexed: 11/16/2022] Open
Abstract
1C1m-Fc, an anti-tumor endothelial marker 1 (TEM-1) scFv-Fc fusion protein antibody, was previously successfully radiolabeled with 177Lu. TEM-1 specific tumor uptake was observed together with a non-saturation dependent liver uptake that could be related to the number of dodecane tetraacetic acid (DOTA) chelator per 1C1m-Fc. The objective of this study was to verify this hypothesis and to find the best DOTA per 1C1m-Fc ratio for theranostic applications. 1C1m-Fc was conjugated with six concentrations of DOTA. High-pressure liquid chromatography, mass spectrometry, immunoreactivity assessment, and biodistribution studies in mice bearing TEM-1 positive tumors were performed. A multi-compartment pharmacokinetic model was used to fit the data and a global pharmacokinetic model was developed to illustrate the effect of liver capture and immunoreactivity loss. Organ absorbed doses in mice were calculated from biodistribution results. A loss of immunoreactivity was observed with the highest DOTA per 1C1m-Fc ratio. Except for the spleen and bone, an increase of DOTA per 1C1m-Fc ratio resulted in an increase of liver uptake and absorbed dose and a decrease of uptake in tumor and other tissues. Pharmacokinetic models correlated these results. The number of DOTA per antibody played a determining role in tumor targeting. One DOTA per 1C1m-Fc gave the best pharmacokinetic behavior for a future translation of [177Lu]Lu-1C1m-Fc in patients.
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Abbas Abadi S, Alirezapour B, Kertész I, Rasaee MJ, Mohammadnejad J, Paknejad M, Yousefnia H, Zolghadri S. Preparation, quality control, and biodistribution assessment of [
111
In]In‐DOTA‐PR81 in BALB/c mice bearing breast tumors. J Labelled Comp Radiopharm 2021; 64:168-180. [DOI: 10.1002/jlcr.3897] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 11/11/2020] [Accepted: 11/27/2020] [Indexed: 02/05/2023]
Affiliation(s)
| | - Behrouz Alirezapour
- Radiation Application Research School Nuclear Science and Technology Research Institute (NSTRI) Tehran Iran
| | - István Kertész
- Department of Nuclear Medicine University of Debrecen Debrecen Hungary
| | - Mohammad Javad Rasaee
- Department of Clinical Biochemistry, School of Medical Siences Tarbiat Modares University (TMU) Tehran Iran
| | - Javad Mohammadnejad
- Department of Life Science Engineering, Faculty of New Sciences & Technologies University of Tehran Tehran Iran
| | - Malihe Paknejad
- Department of Biochemistry, School of Medicine Tehran University of Medical Sciences Tehran Iran
| | - Hassan Yousefnia
- Radiation Application Research School Nuclear Science and Technology Research Institute (NSTRI) Tehran Iran
| | - Samaneh Zolghadri
- Material and Nuclear Fuel Research School Nuclear Science and Technology Research Institute (NSTRI) Tehran Iran
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12
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de Gooyer JM, Elekonawo FMK, Bos DL, van der Post RS, Pèlegrin A, Framery B, Cailler F, Vahrmeijer AL, de Wilt JHW, Rijpkema M. Multimodal CEA-Targeted Image-Guided Colorectal Cancer Surgery using 111In-Labeled SGM-101. Clin Cancer Res 2020; 26:5934-5942. [PMID: 32900795 DOI: 10.1158/1078-0432.ccr-20-2255] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 07/22/2020] [Accepted: 09/02/2020] [Indexed: 12/09/2022]
Abstract
PURPOSE Intraoperative image guidance may aid in clinical decision-making during surgical treatment of colorectal cancer. We developed the dual-labeled carcinoembryonic antigen-targeting tracer, [111In]In-DTPA-SGM-101, for pre- and intraoperative imaging of colorectal cancer. Subsequently, we investigated the tracer in preclinical biodistribution and multimodal image-guided surgery studies, and assessed the clinical feasibility on patient-derived colorectal cancer samples, paving the way for rapid clinical translation. EXPERIMENTAL DESIGN SGM-101 was conjugated with p-isothiocyanatobenzyl-diethylenetriaminepentaacetic acid (DTPA) and labeled with Indium-111 (111In). The biodistribution of 3, 10, 30, and 100 μg [111In]In-DTPA-SGM-101 was assessed in a dose escalation study in BALB/c nude mice with subcutaneous LS174T human colonic tumors, followed by a study to determine the optimal timepoint for imaging. Mice with intraperitoneal LS174T tumors underwent micro-SPECT/CT imaging and fluorescence image-guided resection. In a final translational experiment, we incubated freshly resected human tumor specimens with the tracer and assessed the tumor-to-adjacent tissue ratio of both signals. RESULTS The optimal protein dose of [111In]In-DTPA-SGM-101 was 30 μg (tumor-to-blood ratio, 5.8 ± 1.1) and the optimal timepoint for imaging was 72 hours after injection (tumor-to-blood ratio, 5.1 ± 1.0). In mice with intraperitoneal tumors, [111In]In-DTPA-SGM-101 enabled preoperative SPECT/CT imaging and fluorescence image-guided resection. After incubation of human tumor samples, overall fluorescence and radiosignal intensities were higher in tumor areas compared with adjacent nontumor tissue (P < 0.001). CONCLUSIONS [111In]In-DTPA-SGM-101 showed specific accumulation in colorectal tumors, and enabled micro-SPECT/CT imaging and fluorescence image-guided tumor resection. Thus, [111In]In-DTPA-SGM-101 could be a valuable tool for preoperative SPECT/CT imaging and intraoperative radio-guided localization and fluorescence image-guided resection of colorectal cancer.
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Affiliation(s)
- Jan Marie de Gooyer
- Department of Radiology, Nuclear Medicine & Anatomy, Radboud University Medical Center, Nijmegen, Gelderland, the Netherlands. .,Department of Surgical Oncology, Radboud University Medical Center, Nijmegen, Gelderland, the Netherlands
| | - Fortuné M K Elekonawo
- Department of Radiology, Nuclear Medicine & Anatomy, Radboud University Medical Center, Nijmegen, Gelderland, the Netherlands.,Department of Surgical Oncology, Radboud University Medical Center, Nijmegen, Gelderland, the Netherlands
| | - Desirée L Bos
- Department of Radiology, Nuclear Medicine & Anatomy, Radboud University Medical Center, Nijmegen, Gelderland, the Netherlands
| | - Rachel S van der Post
- Department of Pathology, Radboud University Medical Center, Nijmegen, Gelderland, the Netherlands
| | - André Pèlegrin
- IRCM, Institut de Recherche en Cancérologie de Montpellier, INSERM U1194, Université de Montpellier, Institut régional du Cancer de Montpellier, Montpellier, France
| | | | | | | | - Johannes H W de Wilt
- Department of Surgical Oncology, Radboud University Medical Center, Nijmegen, Gelderland, the Netherlands
| | - Mark Rijpkema
- Department of Radiology, Nuclear Medicine & Anatomy, Radboud University Medical Center, Nijmegen, Gelderland, the Netherlands
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13
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Delage JA, Faivre-Chauvet A, Fierle JK, Gnesin S, Schaefer N, Coukos G, Dunn SM, Viertl D, Prior JO. 177Lu radiolabeling and preclinical theranostic study of 1C1m-Fc: an anti-TEM-1 scFv-Fc fusion protein in soft tissue sarcoma. EJNMMI Res 2020; 10:98. [PMID: 32804276 PMCID: PMC7431510 DOI: 10.1186/s13550-020-00685-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 08/06/2020] [Indexed: 12/21/2022] Open
Abstract
PURPOSE TEM-1 (tumor endothelial marker-1) is a single-pass transmembrane cell surface glycoprotein expressed at high levels by tumor vasculature and malignant cells. We aimed to perform a preclinical investigation of a novel anti-TEM-1 scFv-Fc fusion antibody, 1C1m-Fc, which was radiolabeled with 177Lu for use in soft tissue sarcomas models. METHODS 1C1m-Fc was first conjugated to p-SCN-Bn-DOTA using different excess molar ratios and labeled with 177Lu. To determine radiolabeled antibody immunoreactivity, Lindmo assays were performed. The in vivo behavior of [177Lu]Lu-1C1m-Fc was characterized in mice bearing TEM-1 positive (SK-N-AS) and negative (HT-1080) tumors by biodistribution and single-photon emission SPECT/CT imaging studies. Estimated organ absorbed doses were obtained based on biodistribution results. RESULTS The DOTA conjugation and the labeling with 177Lu were successful with a radiochemical purity of up to 95%. Immunoreactivity after radiolabeling was 86% ± 4%. Biodistribution showed a specific uptake in TEM-1 positive tumor versus liver as critical non-specific healthy organ, and this specificity is correlated to the number of chelates per antibody. A 1.9-fold higher signal at 72 h was observed in SPECT/CT imaging in TEM-1 positive tumors versus control tumors. CONCLUSION TEM-1 is a promising target that could allow a theranostic approach to soft-tissue sarcoma, and 1C1m-Fc appears to be a suitable targeting candidate. In this study, we observed the influence of the ratio DOTA/antibody on the biodistribution. The next step will be to investigate the best conjugation to achieve an optimal tumor-to-organ radioactivity ratio and to perform therapy in murine xenograft models as a prelude to future translation in patients.
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Affiliation(s)
- J A Delage
- Radiopharmacy Unit, Department of Pharmacy, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - A Faivre-Chauvet
- CRCINA, INSERM, CNRS, Université d'Angers, Université de Nantes, Nantes, France
| | - J K Fierle
- LAbCore, Ludwig Institute for Cancer Research, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - S Gnesin
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - N Schaefer
- Department of Nuclear Medicine and Molecular Imaging, Lausanne University Hospital and University of Lausanne, Rue du Bugnon 46, CH-1011, Lausanne, Switzerland
| | - G Coukos
- Ludwig Institute for Cancer Research and Department of Oncology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - S M Dunn
- LAbCore, Ludwig Institute for Cancer Research, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - D Viertl
- Department of Nuclear Medicine and Molecular Imaging, Lausanne University Hospital and University of Lausanne, Rue du Bugnon 46, CH-1011, Lausanne, Switzerland
| | - J O Prior
- Department of Nuclear Medicine and Molecular Imaging, Lausanne University Hospital and University of Lausanne, Rue du Bugnon 46, CH-1011, Lausanne, Switzerland.
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Kasten BB, Ferrone S, Zinn KR, Buchsbaum DJ. B7-H3-targeted Radioimmunotherapy of Human Cancer. Curr Med Chem 2020; 27:4016-4038. [PMID: 30836909 PMCID: PMC8668195 DOI: 10.2174/0929867326666190228120908] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 01/28/2019] [Accepted: 01/28/2019] [Indexed: 12/21/2022]
Abstract
BACKGROUND Targeted Radioimmunotherapy (RIT) is an attractive approach to selectively localize therapeutic radionuclides to malignant cells within primary and metastatic tumors while sparing normal tissues from the effects of radiation. Many human malignancies express B7-H3 on the tumor cell surface, while expression on the majority of normal tissues is limited, presenting B7-H3 as a candidate target for RIT. This review provides an overview of the general principles of targeted RIT and discusses publications that have used radiolabeled B7-H3-targeted antibodies for RIT of cancer in preclinical or clinical studies. METHODS Databases including PubMed, Scopus, and Google Scholar were searched for publications through June 2018 using a combination of terms including "B7-H3", "radioimmunotherapy", "targeted", "radiotherapy", and "cancer". After screening search results for relevancy, ten publications were included for discussion. RESULTS B7-H3-targeted RIT studies to date range from antibody development and assessment of novel Radioimmunoconjugates (RICs) in animal models of human cancer to phase II/III trials in humans. The majority of clinical studies have used B7-H3-targeted RICs for intra- compartment RIT of central nervous system malignancies. The results of these studies have indicated high tolerability and favorable efficacy outcomes, supporting further assessment of B7-H3-targeted RIT in larger trials. Preclinical B7-H3-targeted RIT studies have also shown encouraging therapeutic outcomes in a variety of solid malignancies. CONCLUSION B7-H3-targeted RIT studies over the last 15 years have demonstrated feasibility for clinical development and support future assessment in a broader array of human malignancies. Future directions worthy of exploration include strategies that combine B7-H3- targeted RIT with chemotherapy or immunotherapy.
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Affiliation(s)
- Benjamin B. Kasten
- Department of Neurosurgery, University of Alabama at Birmingham, Birmingham, Alabama, U.S.A
| | - Soldano Ferrone
- Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, U.S.A
| | - Kurt R. Zinn
- Institute for Quantitative Health Science and Engineering, Department of Radiology, Michigan State University, East Lansing, Michigan, U.S.A
| | - Donald J. Buchsbaum
- Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, Alabama, U.S.A
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15
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Deken MM, Bos DL, Tummers WSFJ, March TL, van de Velde CJH, Rijpkema M, Vahrmeijer AL. Multimodal image-guided surgery of HER2-positive breast cancer using [ 111In]In-DTPA-trastuzumab-IRDye800CW in an orthotopic breast tumor model. EJNMMI Res 2019; 9:98. [PMID: 31754913 PMCID: PMC6872692 DOI: 10.1186/s13550-019-0564-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 09/25/2019] [Indexed: 01/23/2023] Open
Abstract
Background Combining modalities using dual-labeled antibodies may allow preoperative and intraoperative tumor localization and could be used in image-guided surgery to improve complete tumor resection. Trastuzumab is a monoclonal antibody against the human epidermal growth factor-2 (HER2) receptor and dual-labeled trastuzumab with both a fluorophore (IRDye800CW) and a radioactive label (111In) can be used for multimodal imaging of HER2-positive breast cancer. The aim of this study was to demonstrate the feasibility of HER2-targeted multimodal imaging using [111In]In-DTPA-trastuzumab-IRDye800CW in an orthotopic breast cancer model. Methods Trastuzumab was conjugated with p-isothiocyanatobenzyl (ITC)-diethylenetriaminepentaacetic acid (DTPA) and IRDye800CW-NHS ester and subsequently labeled with 111In. In a dose escalation study, the biodistribution of 10, 30, and 100 μg [111In]In-DTPA-trastuzumab-IRDye800CW was determined 48 h after injection in BALB/c nude mice with orthotopic high HER2-expressing tumors. Also, a biodistribution study was performed in a low HER2-expressing breast cancer model. In addition, multimodal image-guided surgery was performed in each group. Autoradiography, fluorescence microscopy, and immunohistochemically stained slices of the tumors were compared for co-localization of tumor tissue, HER2 expression, fluorescence, and radiosignal. Results Based on the biodistribution data, a 30 μg dose of dual-labeled trastuzumab (tumor-to-blood ratio 13 ± 2) was chosen for all subsequent studies. [111In]In-DTPA-trastuzumab-IRDye800CW specifically accumulated in orthotopic HER2-positive BT474 tumors (101 ± 7 %IA/g), whereas uptake in orthotopic low HER2-expressing MCF7 tumor was significantly lower (1.2 ± 0.2 %IA/g, p = 0.007). BT474 tumors could clearly be visualized with both micro-SPECT/CT, fluorescence imaging and subsequently, image-guided resection was performed. Immunohistochemical analyses of BT474 tumors demonstrated correspondence in fluorescence, radiosignal, and high HER2 expression. Conclusions Dual-labeled trastuzumab showed specific accumulation in orthotopic HER2-positive BT474 breast tumors with micro-SPECT/CT and fluorescence imaging and enabled image-guided tumor resection. In the clinical setting, [111In]In-DTPA-trastuzumab-IRDye800CW could be valuable for preoperative detection of (metastatic) tumors by SPECT/CT imaging, and intraoperative localization by using a gamma probe and fluorescence image-guided surgery to improve radical resection of tumor tissue in patients with HER2-positive tumors.
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Affiliation(s)
- Marion M Deken
- Department of Surgery, Leiden University Medical Center, Leiden, The Netherlands.
| | - Desirée L Bos
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - Taryn L March
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Mark Rijpkema
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
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16
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Szkop M, Brygoła K, Janczewska M, Ciach T. A simple time-resolved fluorescence assay for quantitative determination of DOTA chelator. Anal Biochem 2019; 584:113384. [PMID: 31356774 DOI: 10.1016/j.ab.2019.113384] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 07/14/2019] [Accepted: 07/25/2019] [Indexed: 01/01/2023]
Abstract
DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate) is one of the preeminent metal chelator applied for diagnostic and therapeutic purposes, however to date there is no versatile and reliable nonradioisotopic method for its precise determination. In this technical note, we present a novel and sensitive fluorimetric assay for quantitative determination of DOTA based on the luminescence quenching of the highly luminescent europium ions complex with trioctyl phosphine oxide and naphthoyl trifluoroacetone sensitizing activators. The assay is carried out in two simple steps and enables the determination of DOTA in the nanomolar range providing a superior tool compared to commonly applied spectrophotometric assay with Arsenazo-III reagent.
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Affiliation(s)
- Michał Szkop
- NanoThea Inc., Waryńskiego 1, 00-645, Warsaw, Poland.
| | - Kamil Brygoła
- NanoThea Inc., Waryńskiego 1, 00-645, Warsaw, Poland
| | | | - Tomasz Ciach
- NanoThea Inc., Waryńskiego 1, 00-645, Warsaw, Poland; Faculty of Chemical and Process Engineering, Warsaw University of Technology, Waryńskiego 1, 00-645, Warsaw, Poland
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Warnders FJ, Lub-de Hooge MN, de Vries EGE, Kosterink JGW. Influence of protein properties and protein modification on biodistribution and tumor uptake of anticancer antibodies, antibody derivatives, and non-Ig scaffolds. Med Res Rev 2018; 38:1837-1873. [PMID: 29635825 DOI: 10.1002/med.21498] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Revised: 01/30/2018] [Accepted: 03/02/2018] [Indexed: 12/11/2022]
Abstract
Newly developed protein drugs that target tumor-associated antigens are often modified in order to increase their therapeutic effect, tumor exposure, and safety profile. During the development of protein drugs, molecular imaging is increasingly used to provide additional information on their in vivo behavior. As a result, there are increasing numbers of studies that demonstrate the effect of protein modification on whole body distribution and tumor uptake of protein drugs. However, much still remains unclear about how to interpret obtained biodistribution data correctly. Consequently, there is a need for more insight in the correct way of interpreting preclinical and clinical imaging data. Summarizing the knowledge gained to date may facilitate this interpretation. This review therefore provides an overview of specific protein properties and modifications that can affect biodistribution and tumor uptake of anticancer antibodies, antibody fragments, and nonimmunoglobulin scaffolds. Protein properties that are discussed in this review are molecular size, target interaction, FcRn binding, and charge. Protein modifications that are discussed are radiolabeling, fluorescent labeling drug conjugation, glycosylation, humanization, albumin binding, and polyethylene glycolation.
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Affiliation(s)
- Frank-Jan Warnders
- Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Marjolijn N Lub-de Hooge
- Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.,Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Elisabeth G E de Vries
- Department of Medical Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Jos G W Kosterink
- Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.,PharmacoTherapy, Epidemiology & Economy, Groningen Research Institute of Pharmacy, University of Groningen, Groningen, The Netherlands
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18
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Kasten BB, Oliver PG, Kim H, Fan J, Ferrone S, Zinn KR, Buchsbaum DJ. 212Pb-Labeled Antibody 225.28 Targeted to Chondroitin Sulfate Proteoglycan 4 for Triple-Negative Breast Cancer Therapy in Mouse Models. Int J Mol Sci 2018; 19:ijms19040925. [PMID: 29561763 PMCID: PMC5979285 DOI: 10.3390/ijms19040925] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Revised: 03/11/2018] [Accepted: 03/15/2018] [Indexed: 01/16/2023] Open
Abstract
Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with a poor prognosis. There is a clinical need for effective, targeted therapy strategies that destroy both differentiated TNBC cells and TNBC cancer initiating cells (CICs), as the latter are implicated in the metastasis and recurrence of TNBC. Chondroitin sulfate proteoglycan 4 (CSPG4) is overexpressed on differentiated tumor cells and CICs obtained from TNBC patient specimens, suggesting that CSPG4 may be a clinically relevant target for the imaging and therapy of TNBC. The purpose of this study was to determine whether α-particle radioimmunotherapy (RIT) targeting TNBC cells using the CSPG4-specific monoclonal antibody (mAb) 225.28 as a carrier was effective at eliminating TNBC tumors in preclinical models. To this end, mAb 225.28 labeled with 212Pb (212Pb-225.28) as a source of α-particles for RIT was used for in vitro Scatchard assays and clonogenic survival assays with human TNBC cells (SUM159 and 2LMP) grown as adherent cells or non-adherent CIC-enriched mammospheres. Immune-deficient mice bearing orthotopic SUM159 or 2LMP xenografts were injected i.v. with the targeted (225.28) or irrelevant isotype-matched control (F3-C25) mAbs, labeled with 99mTc, 125I, or 212Pb for in vivo imaging, biodistribution, or tumor growth inhibition studies. 212Pb-225.28 bound to adherent SUM159 and 2LMP cells and to CICs from SUM159 and 2LMP mammospheres with a mean affinity of 0.5 nM. Nearly ten times more binding sites per cell were present on SUM159 cells and CICs compared with 2LMP cells. 212Pb-225.28 was six to seven times more effective than 212Pb-F3-C25 at inhibiting SUM159 cell and CIC clonogenic survival (p < 0.05). Radiolabeled mAb 225.28 showed significantly higher uptake than radiolabeled mAb F3-C25 in SUM159 and 2LMP xenografts (p < 0.05), and the uptake of 212Pb-225.28 in TNBC xenografts was correlated with target epitope expression. 212Pb-225.28 caused dose-dependent growth inhibition of SUM159 xenografts; 0.30 MBq 212Pb-225.28 was significantly more effective than 0.33 MBq 212Pb-F3-C25 at inhibiting tumor growth (p < 0.01). These results suggest that CSPG4-specific 212Pb-225.28 is a useful reagent for RIT of CSPG4-expressing tumors, including metastatic TNBC.
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Affiliation(s)
- Benjamin B Kasten
- Department of Radiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| | - Patsy G Oliver
- Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| | - Harrison Kim
- Department of Radiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| | - Jinda Fan
- Department of Radiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| | - Soldano Ferrone
- Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
| | - Kurt R Zinn
- Institute for Quantitative Health Science and Engineering, Department of Radiology, Michigan State University, East Lansing, MI 48824, USA.
| | - Donald J Buchsbaum
- Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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Kasten BB, Gangrade A, Kim H, Fan J, Ferrone S, Ferrone CR, Zinn KR, Buchsbaum DJ. 212Pb-labeled B7-H3-targeting antibody for pancreatic cancer therapy in mouse models. Nucl Med Biol 2017; 58:67-73. [PMID: 29413459 DOI: 10.1016/j.nucmedbio.2017.12.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 12/02/2017] [Accepted: 12/13/2017] [Indexed: 12/14/2022]
Abstract
INTRODUCTION We recently validated monoclonal antibody (mAb) 376.96 as an effective carrier for targeted α-particle radioimmunotherapy (RIT) with 212Pb in ovarian cancer mouse models. In this study, we tested the binding of radiolabeled mAb 376.96 to human pancreatic ductal adenocarcinoma (PDAC) cells and localization in xenografts in immune-deficient mice and evaluated 212Pb-labeled 376.96 (212Pb-376.96) for PDAC therapy. METHODS In vitro Scatchard assays assessed the specific binding of 212Pb-376.96 to human PDAC3 adherent differentiated cells and non-adherent cancer initiating cells (CICs) dissociated from tumorspheres. In vitro clonogenic assays were used to measure the proliferation of adherent PDAC3 cells and CIC-enriched tumorspheres treated with 212Pb-376.96 or the irrelevant isotype-matched 212Pb-F3-C25. Mice bearing patient derived pancreatic cancer Panc039 xenografts were i.v. injected with 0.17-0.70 MBq 212Pb-376.96 or isotype control 212Pb-F3-C25, and used for biodistribution and tumor growth inhibition studies. Mice bearing orthotopic PDAC3 xenografts were i.v. co-injected with 99mTc-376.96 and 125I-F3-C25 and used for biodistribution studies. RESULTS 212Pb-376.96 specifically bound to PDAC3 adherent and dissociated tumorsphere CICs; Kd values averaged 9.0 and 21.7 nM, respectively, with 104-105 binding sites/cell. 212Pb-376.96 inhibited the clonogenic survival of PDAC3 cells or CICs dissociated from tumorspheres 3-6 times more effectively than isotype-matched control 212Pb-F3-C25. Panc039 s.c. tumors showed significantly higher uptake of 212Pb-376.96 (14.0 ± 2.1% ID/g) compared to 212Pb-F3-C25 (6.5 ± 0.9% ID/g, p < .001) at 24 h after dosing. Orthotopic PDAC3 tumors showed significantly higher uptake of 99mTc-376.96 (6.4 ± 1.8% ID/g) compared to 125I-F3-C25 (3.9 ± 0.9% ID/g, p < .05) at 24 h after dosing. Panc039 tumor growth was significantly inhibited by 212Pb-376.96 compared to 212Pb-F3-C25 or non-treated control tumors (p < .05). CONCLUSION Our results provide evidence for the efficacy of B7-H3 targeted RIT against preclinical models of pancreatic ductal adenocarcinoma (PDAC) and support future studies with 212Pb-376.96 in combination with chemotherapy to potentiate efficacy against PDAC.
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Affiliation(s)
- Benjamin B Kasten
- Department of Radiology, University of Alabama at Birmingham, Birmingham, AL, United States.
| | - Abhishek Gangrade
- Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Harrison Kim
- Department of Radiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Jinda Fan
- Department of Radiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Soldano Ferrone
- Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Cristina R Ferrone
- Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Kurt R Zinn
- Institute for Quantitative Health Science and Engineering, Department of Radiology, Michigan State University, East Lansing, MI, United States
| | - Donald J Buchsbaum
- Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, AL, United States
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Nesměrák K, Třmínková P. Spectrometric methods for determination of ligand–protein ratio in monoclonal conjugates: a mini review. MONATSHEFTE FUR CHEMIE 2016. [DOI: 10.1007/s00706-016-1747-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Development of [⁶⁴Cu]-DOTA-PR81 radioimmunoconjugate for MUC-1 positive PET imaging. Nucl Med Biol 2015; 43:73-80. [PMID: 26453525 DOI: 10.1016/j.nucmedbio.2015.07.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Revised: 06/29/2015] [Accepted: 07/29/2015] [Indexed: 11/24/2022]
Abstract
OBJECTIVE Breast cancer radioimmunoscintigraphy targeting MUC1 expression is a growing field of work in nuclear medicine research. PR81 is a monoclonal antibody that binds with high affinity to MUC1, which is over expressed on breast tumors. In this study, we report production, quality control and preclinical qualifications of a copper-64 labeled PR81 for PET imaging of breast cancer. METHODS PR81 was conjugated with DOTA-NHS-ester and purified by molecular filtration followed by chelate:mAb ratio determination by spectrophotometric method. DOTA-PR81 was labeled with (64)Cu followed by radiochemical purity, in vitro stability, in vitro internalization and immunoreactivity determination. The tissue biodistribution of the (64)Cu-DOTA-PR81 and (64)Cu-DOTA-hIgG was evaluated in BALB/c mice with breast carcinoma tumors using tissue counting and imaging. RESULTS The radiochemical purity of radioimmunoconjugate was >95±1.9% (ITLC) (specific activity; 4.6 μCi/μg). The average number of chelators per antibody was 3.4±0.3:1. The (64)Cu-DOTA-PR81 showed immunoreactivity towards MUC1 antigen and MCF7 cell line with significant in vitro stability (>89% in PBS and 78±0.5% in human serum) over 48 h. Maximum internalized activity of radiolabeled PR81 in 4-8 h was 81.5%. The biodistribution and scintigraphy studies showed the accumulation of the complex at the site of tumors with high sensitivity and specificity compared to control probes. CONCLUSION The results showed that (64)Cu-DOTA-PR81 may be considered as a potential PET tracer for diagnosis and follow-up of MUC1 expression in oncology.
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Rijpkema M, Bos DL, Cornelissen AS, Franssen GM, Goldenberg DM, Oyen WJ, Boerman OC. Optimization of Dual-Labeled Antibodies for Targeted Intraoperative Imaging of Tumors. Mol Imaging 2015. [DOI: 10.2310/7290.2015.00015] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Mark Rijpkema
- From the Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, the Netherlands; Immunomedics, Inc., Morris Plains, NJ; and Garden State Cancer Center, Center for Molecular Medicine and Immunology, Morris Plains, NJ
| | - Desirée L. Bos
- From the Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, the Netherlands; Immunomedics, Inc., Morris Plains, NJ; and Garden State Cancer Center, Center for Molecular Medicine and Immunology, Morris Plains, NJ
| | - Alex S. Cornelissen
- From the Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, the Netherlands; Immunomedics, Inc., Morris Plains, NJ; and Garden State Cancer Center, Center for Molecular Medicine and Immunology, Morris Plains, NJ
| | - Gerben M. Franssen
- From the Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, the Netherlands; Immunomedics, Inc., Morris Plains, NJ; and Garden State Cancer Center, Center for Molecular Medicine and Immunology, Morris Plains, NJ
| | - David M. Goldenberg
- From the Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, the Netherlands; Immunomedics, Inc., Morris Plains, NJ; and Garden State Cancer Center, Center for Molecular Medicine and Immunology, Morris Plains, NJ
| | - Wim J. Oyen
- From the Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, the Netherlands; Immunomedics, Inc., Morris Plains, NJ; and Garden State Cancer Center, Center for Molecular Medicine and Immunology, Morris Plains, NJ
| | - Otto C. Boerman
- From the Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, the Netherlands; Immunomedics, Inc., Morris Plains, NJ; and Garden State Cancer Center, Center for Molecular Medicine and Immunology, Morris Plains, NJ
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Charmsaz S, Beckett K, Smith FM, Bruedigam C, Moore AS, Al-Ejeh F, Lane SW, Boyd AW. EphA2 Is a Therapy Target in EphA2-Positive Leukemias but Is Not Essential for Normal Hematopoiesis or Leukemia. PLoS One 2015; 10:e0130692. [PMID: 26083390 PMCID: PMC4470658 DOI: 10.1371/journal.pone.0130692] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 05/24/2015] [Indexed: 12/20/2022] Open
Abstract
Members of the Eph family of receptor tyrosine kinases and their membrane bound ephrin ligands have been shown to play critical roles in many developmental processes and more recently have been implicated in both normal and pathological processes in post-embryonic tissues. In particular, expression studies of Eph receptors and limited functional studies have demonstrated a role for the Eph/ephrin system in hematopoiesis and leukemogenesis. In particular, EphA2 was reported on hematopoietic stem cells and stromal cells. There are also reports of EphA2 expression in many different types of malignancies including leukemia, however there is a lack of knowledge in understanding the role of EphA2 in hematopoiesis and leukemogenesis. We explored the role of EphA2 in hematopoiesis by analyzing wild type and EphA2 knockout mice. Mature, differentiated cells, progenitors and hematopoietic stem cells derived from knockout and control mice were analyzed and no significant abnormality was detected. These studies showed that EphA2 does not have an obligatory role in normal hematopoiesis. Comparative studies using EphA2-negative MLL-AF9 leukemias derived from EphA2-knockout animals showed that there was no detectable functional role for EphA2 in the initiation or progression of the leukemic process. However, expression of EphA2 in leukemias initiated by MLL-AF9 suggested that this protein might be a possible therapy target in this type of leukemia. We showed that treatment with EphA2 monoclonal antibody IF7 alone had no effect on tumorigenicity and latency of the MLL-AF9 leukemias, while targeting of EphA2 using EphA2 monoclonal antibody with a radioactive payload significantly impaired the leukemic process. Altogether, these results identify EphA2 as a potential radio-therapeutic target in leukemias with MLL translocation.
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Affiliation(s)
- Sara Charmsaz
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
- * E-mail:
| | | | - Fiona M. Smith
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | | | - Andrew S. Moore
- The University of Queensland, Brisbane, Australia
- Children’s Health Queensland Hospital and Health Service, Brisbane, Australia
| | - Fares Al-Ejeh
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Steven W. Lane
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
- The University of Queensland, Brisbane, Australia
| | - Andrew W. Boyd
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
- The University of Queensland, Brisbane, Australia
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Schjoeth-Eskesen C, Nielsen CH, Heissel S, Højrup P, Hansen PR, Gillings N, Kjaer A. [(64) Cu]-labelled trastuzumab: optimisation of labelling by DOTA and NODAGA conjugation and initial evaluation in mice. J Labelled Comp Radiopharm 2015; 58:227-33. [PMID: 25906708 PMCID: PMC5029596 DOI: 10.1002/jlcr.3287] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 03/10/2015] [Accepted: 03/11/2015] [Indexed: 12/28/2022]
Abstract
The human epidermal growth factor receptor‐2 (HER2) is overexpressed in 20–30% of all breast cancer cases, leading to increased cell proliferation, growth and migration. The monoclonal antibody, trastuzumab, binds to HER2 and is used for treatment of HER2‐positive breast cancer. Trastuzumab has previously been labelled with copper‐64 by conjugation of a 1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetic acid (DOTA) chelator. The aim of this study was to optimise the 64Cu‐labelling of DOTA‐trastuzumab and as the first to produce and compare with its 1,4,7‐triazacyclononane, 1‐glutaric acid‐5,7 acetic acid (NODAGA) analogue in a preliminary HER2 tumour mouse model. The chelators were conjugated to trastuzumab using the activated esters DOTA mono‐N‐hydroxysuccinimide (NHS) and NODAGA‐NHS. 64Cu‐labelling of DOTA‐trastuzumab was studied by varying the amount of DOTA‐trastuzumab used, reaction temperature and time. Full 64Cu incorporation could be achieved using a minimum of 10‐µg DOTA‐trastuzumab, but the fastest labelling was obtained after 15 min at room temperature using 25 µg of DOTA‐trastuzumab. In comparison, 80% incorporation was achieved for 64Cu‐labelling of NODAGA‐trastuzumab. Both [64Cu]DOTA‐trastuzumab and [64Cu]NODAGA‐trastuzumab were produced after purification with radiochemical purities of >97%. The tracers were injected into mice with HER2 expressing tumours. The mice were imaged by positron emission tomography and showed high tumour uptake of 3–9% ID/g for both tracers.
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Affiliation(s)
- Christina Schjoeth-Eskesen
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen, Denmark.,Cluster for Molecular Imaging, University of Copenhagen, Copenhagen, Denmark
| | - Carsten Haagen Nielsen
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen, Denmark.,Cluster for Molecular Imaging, University of Copenhagen, Copenhagen, Denmark
| | - Søren Heissel
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Peter Højrup
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Paul Robert Hansen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Nic Gillings
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen, Denmark
| | - Andreas Kjaer
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen, Denmark.,Cluster for Molecular Imaging, University of Copenhagen, Copenhagen, Denmark
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Autoradiography imaging in targeted alpha therapy with Timepix detector. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2015; 2015:612580. [PMID: 25688285 PMCID: PMC4320936 DOI: 10.1155/2015/612580] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 10/14/2014] [Indexed: 11/17/2022]
Abstract
There is a lack of data related to activity uptake and particle track distribution in targeted alpha therapy. These data are required to estimate the absorbed dose on a cellular level as alpha particles have a limited range and traverse only a few cells. Tracking of individual alpha particles is possible using the Timepix semiconductor radiation detector. We investigated the feasibility of imaging alpha particle emissions in tumour sections from mice treated with Thorium-227 (using APOMAB), with and without prior chemotherapy and Timepix detector. Additionally, the sensitivity of the Timepix detector to monitor variations in tumour uptake based on the necrotic tissue volume was also studied. Compartmental analysis model was used, based on the obtained imaging data, to assess the Th-227 uptake. Results show that alpha particle, photon, electron, and muon tracks were detected and resolved by Timepix detector. The current study demonstrated that individual alpha particle emissions, resulting from targeted alpha therapy, can be visualised and quantified using Timepix detector. Furthermore, the variations in the uptake based on the tumour necrotic volume have been observed with four times higher uptake for tumours pretreated with chemotherapy than for those without chemotherapy.
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Staudacher AH, Al-Ejeh F, Fraser CK, Darby JM, Roder DM, Ruszkiewicz A, Manavis J, Brown MP. The La antigen is over-expressed in lung cancer and is a selective dead cancer cell target for radioimmunotherapy using the La-specific antibody APOMAB®. EJNMMI Res 2014; 4:2. [PMID: 24387284 PMCID: PMC3882100 DOI: 10.1186/2191-219x-4-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 12/23/2013] [Indexed: 11/21/2022] Open
Abstract
Background The lupus-associated (La)-specific murine monoclonal antibody DAB4 (APOMAB®) specifically binds dead cancer cells. Using DAB4, we examined La expression in human lung cancer samples to assess its suitability as a cancer-selective therapeutic target. We evaluated the safety and effectiveness of radioimmunotherapy (RIT) using DAB4 radiolabeled with Lutetium-177 (177Lu) in the murine Lewis Lung (LL2) carcinoma model, and determined whether combining RIT with DNA-damaging cisplatin-based chemotherapy, a PARP inhibitor (PARPi), or both alters treatment responses. Methods The expression of La mRNA in human lung cancer samples was analysed using the online database Oncomine, and the protein expression of La was examined using a TissueFocus Cancer Survey Tissue Microarray. The binding of DAB4 to cisplatin-treated LL2 cells was assessed in vitro. LL2 tumour-bearing mice were administered escalating doses of 177Lu-DAB4 alone or in combination with chemotherapy, and tumour growth and survival measured. Biodistribution analysis was used to determine tissue uptake of 177Lu-DAB4 or its isotype control (177Lu-Sal5), when delivered alone or after chemotherapy. PARPi (rucaparib; AG-014699) was combined with chemotherapy and the effects of combined treatment on tumour growth, tumour cell DNA damage and death, and intratumoural DAB4 binding were also analysed. The effect of the triple combination of PARPi, chemotherapy and 177Lu-DAB4 on tumour growth and survival of LL2 tumour-bearing mice was tested. Results La was over-expressed at both mRNA and protein levels in surgical specimens of human lung cancer and the over-expression of La mRNA conferred a poorer prognosis. DAB4 bound specifically to cisplatin-induced dead LL2 cells in vitro. An anti-tumour dose response was observed when escalating doses of 177Lu-DAB4 were delivered in vivo, with supra-additive responses observed when chemotherapy was combined with 177Lu-DAB4. Combining PARPi with chemotherapy was more effective than chemotherapy alone with increased tumour cell DNA damage and death, and intratumoural DAB4 binding. The combination of PARPi, chemotherapy and 177Lu-DAB4 was well-tolerated and maximised tumour growth delay. Conclusions The La antigen represents a dead cancer cell-specific target in lung cancer, and DAB4 specifically targeted tumour tissue in vivo, particularly after chemotherapy. Tumour uptake of DAB4 increased further after the combination of PARPi and chemotherapy, which generated new dead tumour cell-binding targets. Consequently, combining 177Lu-DAB4 with PARPi and chemotherapy produced the greatest anti-tumour response. Therefore, the triple combination of PARPi, chemotherapy and RIT may have broad clinical utility.
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Affiliation(s)
- Alexander H Staudacher
- Translational Oncology Laboratory, Centre for Cancer Biology, SA Pathology, Adelaide, Australia.
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Ranson M, Berghofer P, Vine KL, Greguric I, Shepherd R, Katsifis A. Different radiolabelling methods alter the pharmacokinetic and biodistribution properties of Plasminogen Activator Inhibitor Type 2 (PAI-2) forms. Nucl Med Biol 2012; 39:833-9. [DOI: 10.1016/j.nucmedbio.2012.01.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 12/22/2011] [Accepted: 01/17/2012] [Indexed: 11/28/2022]
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Adair JR, Howard PW, Hartley JA, Williams DG, Chester KA. Antibody–drug conjugates – a perfect synergy. Expert Opin Biol Ther 2012; 12:1191-206. [DOI: 10.1517/14712598.2012.693473] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Boswell CA, Mundo EE, Zhang C, Bumbaca D, Valle NR, Kozak KR, Fourie A, Chuh J, Koppada N, Saad O, Gill H, Shen BQ, Rubinfeld B, Tibbitts J, Kaur S, Theil FP, Fielder PJ, Khawli LA, Lin K. Impact of drug conjugation on pharmacokinetics and tissue distribution of anti-STEAP1 antibody-drug conjugates in rats. Bioconjug Chem 2011; 22:1994-2004. [PMID: 21913715 DOI: 10.1021/bc200212a] [Citation(s) in RCA: 149] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Antibody-drug conjugates (ADCs) are designed to combine the exquisite specificity of antibodies to target tumor antigens with the cytotoxic potency of chemotherapeutic drugs. In addition to the general chemical stability of the linker, a thorough understanding of the relationship between ADC composition and biological disposition is necessary to ensure that the therapeutic window is not compromised by altered pharmacokinetics (PK), tissue distribution, and/or potential organ toxicity. The six-transmembrane epithelial antigen of prostate 1 (STEAP1) is being pursued as a tumor antigen target. To assess the role of ADC composition in PK, we evaluated plasma and tissue PK profiles in rats, following a single dose, of a humanized anti-STEAP1 IgG1 antibody, a thio-anti-STEAP1 (ThioMab) variant, and two corresponding thioether-linked monomethylauristatin E (MMAE) drug conjugates modified through interchain disulfide cysteine residues (ADC) and engineered cysteines (TDC), respectively. Plasma PK of total antibody measured by enzyme-linked immunosorbent assay (ELISA) revealed ∼45% faster clearance for the ADC relative to the parent antibody, but no apparent difference in clearance between the TDC and unconjugated parent ThioMab. Total antibody clearances of the two unconjugated antibodies were similar, suggesting minimal effects on PK from cysteine mutation. An ELISA specific for MMAE-conjugated antibody indicated that the ADC cleared more rapidly than the TDC, but total antibody ELISA showed comparable clearance for the two drug conjugates. Furthermore, consistent with relative drug load, the ADC had a greater magnitude of drug deconjugation than the TDC in terms of free plasma MMAE levels. Antibody conjugation had a noticeable, albeit minor, impact on tissue distribution with a general trend toward increased hepatic uptake and reduced levels in other highly vascularized organs. Liver uptakes of ADC and TDC at 5 days postinjection were 2-fold and 1.3-fold higher, respectively, relative to the unmodified antibodies. Taken together, these results indicate that the degree of overall structural modification in anti-STEAP1-MMAE conjugates has a corresponding level of impact on both PK and tissue distribution.
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Affiliation(s)
- C Andrew Boswell
- Department of Pharmacokinetic & Pharmacodynamic Sciences, Genentech Research & Early Development, South San Francisco, California 94080, United States
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Shin IS, Lee SM, Kim HS, Yao Z, Regino C, Sato N, Cheng KT, Hassan R, Campo MF, Albone EF, Choyke PL, Pastan I, Paik CH. Effect of chelator conjugation level and injection dose on tumor and organ uptake of 111In-labeled MORAb-009, an anti-mesothelin antibody. Nucl Med Biol 2011; 38:1119-27. [PMID: 21741258 DOI: 10.1016/j.nucmedbio.2011.05.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 04/27/2011] [Accepted: 05/13/2011] [Indexed: 10/18/2022]
Abstract
INTRODUCTION Radiolabeling of a monoclonal antibody (mAb) with a metallic radionuclide requires the conjugation of a bifunctional chelator to the mAb. The conjugation, however, can alter the physical and immunological properties of the mAb, consequently affecting its tumor-targeting pharmacokinetics. In this study, we investigated the effect of the amount of 2-(p-isothiocyanatobenzyl)-cyclohexyl-diethylenetriamine-pentaacetic acid (CHX-A″) conjugated to MORAb-009, a mAb directed against mesothelin, and the effect of MORAb dose on the biodistribution of (111)In-labeled MORAb-009. METHODS We used nude mice bearing the A431/K5 tumor as a mesothelin-positive tumor model and the A431 tumor as a mesothelin-negative control. To find the optimal level of CHX-A″ conjugation, CHX-A″-MORAb-009 conjugates with 2.4, 3.5 and 5.5 CHX-A″ molecules were investigated. To investigate the effect of injected MORAb-009 dose on neutralizing the shed mesothelin in the circulation, biodistribution studies were performed after the intravenous co-injection of (111)In-labeled MORAb-009 (2.4 CHX-A″/MORAb-009) with three different doses: 0.2, 2 and 30 μg of MORAb-009. RESULTS The tumor uptake in A431/K5 tumor was four times higher than that in A431 tumor, indicating that the tumor uptake in A431/K5 was mesothelin mediated. The conjugate with 5.5 CHX-A″ showed a lower isoelectric point (pI) and lower immunoreactivity (IR) than the 2.4 CHX-A″ conjugate. These differences were reflected in the biodistribution of the (111)In label. The (111)In-labeled MORAb-009 conjugated with 2.4 CHX-A″ produced higher tumor uptake and lower liver and spleen uptakes than the 5.5 CHX-A″ conjugate. The biodistribution studies also revealed that the tumor uptake was significantly affected by the injected MORAb-009 dose and tumor size. The 30-μg dose produced higher tumor uptake than the 0.2- and 2-μg doses, whereas the 30-μg dose produced lower liver and spleen uptakes than the 0.2-μg dose. CONCLUSION This study demonstrates that the number of chelate conjugation and the injected dose are two important parameters to achieve high tumor and low non-target organ uptake of (111)In-labeled MORAb-009. This study also suggests that the injected dose of mAb could be individualized based on the tumor size or the blood level of shed antigen in a patient to achieve the ideal tumor-to-organ radioactivity ratios.
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Affiliation(s)
- In Soo Shin
- Radiopharmaceutical Laboratory, Division of Nuclear Medicine, Department of Radiology and Imaging Sciences, NIH Clinical Center, Bethesda, MD 20892, USA
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Langford JH, Cooper MS, Orchard KH. Development and validation of the 57Co assay for determining the ligand to antibody ratio in bifunctional chelate/antibody conjugates for use in radioimmunotherapy. Nucl Med Biol 2011; 38:1103-10. [PMID: 21741259 DOI: 10.1016/j.nucmedbio.2011.05.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Revised: 03/22/2011] [Accepted: 05/02/2011] [Indexed: 11/30/2022]
Abstract
INTRODUCTION The ligand to antibody ratio is an important characteristic of a chelate/antibody conjugate. It has been widely reported that if the ratio is too high, there will be detrimental effects on immunoreactivity and biodistribution; conversely, if the ratio is too low, the radionuclide may not bind efficiently, and the stability and the specific activity will be reduced. There are little published data on the accuracy or precision of the (57)Co assay. The UK Clinical Trials Regulations state that "systems with procedures that assure the quality of every aspect of the trial should be implemented". The aims of this study were to assess the reliability and accuracy of the (57)Co binding assay and validate it against defined criteria. METHOD Thirty-two serial assays were assessed for reliability. Two batches of conjugated antibody were also analysed by matrix-assisted laser desorption/ionisation time of flight (MALDI-TOF) mass spectrometry (MS) to allow the comparison of the functional test with a physical method. RESULTS Reliability: The coefficient of variation was 0.13. Accuracy: There was 9% variation between the (57)Co binding assay and MALDI-TOF MS results. CONCLUSION A detailed method for the (57)Co ligand to antibody test is described that allows a discrete value to be obtained. The assay was validated as fit for purpose against target values of coefficient of variation <0.20, accuracy±10%, over a permissive range of 0.5-3.0 ligand to antibody ratio.
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Affiliation(s)
- Jonathan H Langford
- Southampton University School of Medicine (Cancer Sciences), Southampton, UK.
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Comparison of (99m)Tc-labeled PR81 and its F(ab')₂ fragments as radioimmunoscintigraphy agents for breast cancer imaging. Ann Nucl Med 2011; 25:87-92. [PMID: 21061190 DOI: 10.1007/s12149-010-0434-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Accepted: 09/15/2010] [Indexed: 01/14/2023]
Abstract
OBJECTIVE We digested anti-MUC1 monoclonal antibody PR81 to produce F(ab')₂ fragments. A comparison was performed between the two radiolabeled PR81 and F(ab')₂ fragments for breast tumor imaging in a mouse model. METHODS The optimum conditions for pepsin digestion of PR81 were investigated in terms of enzymes: antibody ratio, digestion time duration and preserved immunoreactivity of the produced fragments. The F(ab')₂ fragments were labeled with Technetium-99m using HYNIC as a chelator and tricine as a co-ligand. The immunoreactivity of the complexes was assessed by radioimmunoassay using MCF7 cells. Biodistribution and imaging studies were performed in female BALB/c mice with breast tumor xenograft at 4, 8 and 24 h post-administration. The PR81 was labeled with technetium-99m in the same way for comparison. RESULTS The optimum time duration for PR81 digestion was found to be 28 h at an enzyme:antibody weight ratio of 1:20 that resulted in 95.2 ± 4.7% purity. The labeling of intact PR81 and its F(ab')₂ fragments were 87.6 ± 4.2 and 76.1 ± 3.3% after 1 h, respectively (p value <0.05). The percentage of immunoreactivity of F(ab')₂ fragments and intact PR81 were 75.4 ± 2.1% and 85.7 ± 2.9%, respectively (p value <0.05). The biodistribution and imaging studies demonstrated localization of the fragments at 4 h post-administration with high sensitivity and specificity. CONCLUSION The results showed that F(ab')₂ fragment of PR81 is more suitable than intact PR81 for safer and more rapid detection of human breast cancer.
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Comparison of the in vivo distribution of four different annexin a5 adducts in rhesus monkeys. INTERNATIONAL JOURNAL OF MOLECULAR IMAGING 2011; 2011:405840. [PMID: 21629847 PMCID: PMC3099189 DOI: 10.1155/2011/405840] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Revised: 01/19/2011] [Accepted: 02/23/2011] [Indexed: 12/29/2022]
Abstract
Annexin A5 has been used for the detection of apoptotic cells, due to its ability to bind to phosphatidylserine (PS). Four different labeled Annexin A5 adducts were evaluated in rhesus monkey, with radiolabeling achieved via 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA). Of these adducts differing conjugation methods were employed which resulted in nonspecific radiolabeling (AxA5-I), or site-specific radiolabeling (AxA5-II). A nonbinding variant of Annexin A5 was also evaluated (AxA5-IINBV), conjugation here was site specific. The fourth adduct examined had both specific and nonspecific conjugation techniques employed (AxA5-IImDOTA). Blood clearance for each adduct was comparable, while appreciable uptake was observed in kidney, liver, and spleen. Significant differences in uptake of AxA5-I and AxA5-II were observed, as well as between AxA5-II and AxA5-IINBV. No difference between AxA5-II and AxA5-IImDOTA was observed, suggesting that conjugating DOTA nonspecifically did not affect the in vivo biodistribution of Annexin A5.
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Al-Ejeh F, Darby JM, Brown MP. Chemotherapy synergizes with radioimmunotherapy targeting La autoantigen in tumors. PLoS One 2009; 4:e4630. [PMID: 19247485 PMCID: PMC2645682 DOI: 10.1371/journal.pone.0004630] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Accepted: 01/12/2009] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND To date, inefficient delivery of therapeutic doses of radionuclides to solid tumors limits the clinical utility of radioimmunotherapy. We aim to test the therapeutic utility of Yttrium-90 ((90)Y)-radio-conjugates of a monoclonal antibody, which we showed previously to bind specifically to the abundant intracellular La ribonucleoprotein revealed in dead tumor cells after DNA-damaging treatment. METHODOLOGY/PRINCIPAL FINDINGS Immunoconjugates of the DAB4 clone of the La-specific monoclonal antibody, APOMAB, were prepared using the metal chelator, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), and then radiolabeled with (90)Y. Mice bearing established subcutaneous tumors were treated with (90)Y-DOTA-DAB4 alone or after chemotherapy. Non-radiosensitizing cyclophosphamide/etoposide chemotherapy was used for the syngeneic EL4 lymphoma model. Radiosensitizing cisplatin/gemcitabine chemotherapy was used for the syngeneic Lewis Lung carcinoma (LL2) model, and for the xenograft models of LNCaP prostatic carcinoma and Panc-1 pancreatic carcinoma. We demonstrate the safety, specificity, and efficacy of (90)Y-DOTA-DAB4-radioimmunotherapy alone or combined with chemotherapy. EL4 lymphoma-bearing mice either were cured at higher doses of radioimmunotherapy alone or lower doses of radioimmunotherapy in synergy with chemotherapy. Radioimmunotherapy alone was less effective in chemo- and radio-resistant carcinoma models. However, radioimmunotherapy synergized with radiosensitizing chemotherapy to retard significantly tumor regrowth and so prolong the survival of mice bearing LL2, LNCaP, or Panc-1 subcutaneous tumor implants. CONCLUSIONS/SIGNIFICANCE We report proof-of-concept data supporting a unique form of radioimmunotherapy, which delivers bystander killing to viable cancer cells after targeting the universal cancer antigen, La, created by DNA-damaging treatment in neighboring dead cancer cells. Subsequently we propose that DAB4-targeted ionizing radiation induces additional cycles of tumor cell death, which further augments DAB4 binding to produce a tumor-lethal 'genotoxic chain reaction'. Clinically, this approach may be useful as consolidation treatment after a drug-induced cell death among (small-volume) metastatic deposits, the commonest cause of cancer death. This article is part II of a two-part series providing proof-of-concept for the diagnostic and therapeutic use of the DAB4 clone of the La-specific monoclonal antibody, APOMAB.
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Affiliation(s)
- Fares Al-Ejeh
- Experimental Therapeutics Laboratory, Hanson Institute, Adelaide, South Australia, Australia
| | - Jocelyn M. Darby
- Experimental Therapeutics Laboratory, Hanson Institute, Adelaide, South Australia, Australia
| | - Michael P. Brown
- Experimental Therapeutics Laboratory, Hanson Institute, Adelaide, South Australia, Australia
- Department of Medical Oncology, Royal Adelaide Hospital and School of Medicine, The University of Adelaide, Adelaide, South Australia, Australia
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Al-Ejeh F, Darby JM, Tsopelas C, Smyth D, Manavis J, Brown MP. APOMAB, a La-specific monoclonal antibody, detects the apoptotic tumor response to life-prolonging and DNA-damaging chemotherapy. PLoS One 2009; 4:e4558. [PMID: 19247492 PMCID: PMC2645692 DOI: 10.1371/journal.pone.0004558] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Accepted: 01/16/2009] [Indexed: 12/16/2022] Open
Abstract
Background Antineoplastic therapy may impair the survival of malignant cells to produce cell death. Consequently, direct measurement of tumor cell death in vivo is a highly desirable component of therapy response monitoring. We have previously shown that APOMAB® representing the DAB4 clone of a La/SSB-specific murine monoclonal autoantibody is a malignant cell-death ligand, which accumulates preferentially in tumors in an antigen-specific and dose-dependent manner after DNA-damaging chemotherapy. Here, we aim to image tumor uptake of APOMAB® (DAB4) and to define its biological correlates. Methodology/Principal Findings Brisk tumor cell apoptosis is induced in the syngeneic EL4 lymphoma model after treatment of tumor-bearing mice with DNA-damaging cyclophosphamide/etoposide chemotherapy. Tumor and normal organ accumulation of Indium 111 (111In)-labeled La-specific DAB4 mAb as whole IgG or IgG fragments was quantified by whole-body static imaging and organ assay in tumor-bearing mice. Immunohistochemical measurements of tumor caspase-3 activation and PARP-1 cleavage, which are indicators of early and late apoptosis, respectively, were correlated with tumor accumulation of DAB4. Increased tumor accumulation of DAB4 was associated directly with both the extent of chemotherapy-induced tumor cell death and DAB4 binding per dead tumor cell. Tumor DAB4 accumulation correlated with cumulative caspase-3 activation and PARP-1 cleavage as tumor biomarkers of apoptosis and was directly related to the extended median survival time of tumor-bearing mice. Conclusions/Significance Radiolabeled La-specific monoclonal antibody, DAB4, detected dead tumor cells after chemotherapy, rather than chemosensitive normal tissues of gut and bone marrow. DAB4 identified late apoptotic tumor cells in vivo. Hence, radiolabeled DAB4 may usefully image responses to human carcinoma therapy because DAB4 would capture the protracted cell death of carcinoma. We believe that the ability of radiolabeled DAB4 to rapidly assess the apoptotic tumor response and, consequently, to potentially predict extended survival justifies its future clinical development as a radioimmunoscintigraphic agent. This article is part I of a two-part series providing proof-of-concept for the the diagnostic and therapeutic use of a La-specific monoclonal antibody, the DAB4 clone of which is represented by the registered trademark, APOMAB®.
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Affiliation(s)
- Fares Al-Ejeh
- Experimental Therapeutics Laboratory, Hanson Institute, Adelaide, South Australia, Australia
| | - Jocelyn M. Darby
- Experimental Therapeutics Laboratory, Hanson Institute, Adelaide, South Australia, Australia
| | - Chris Tsopelas
- Department of Nuclear Medicine, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Douglas Smyth
- Department of Nuclear Medicine, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Jim Manavis
- Centre for Neurological Disease, Hanson Institute, Adelaide, South Australia, Australia
| | - Michael P. Brown
- Experimental Therapeutics Laboratory, Hanson Institute, Adelaide, South Australia, Australia
- Department of Medical Oncology, Royal Adelaide Hospital Cancer Centre and School of Medicine, The University of Adelaide, Adelaide, South Australia, Australia
- * E-mail:
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