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Recent progress of astatine-211 in endoradiotherapy: Great advances from fundamental properties to targeted radiopharmaceuticals. CHINESE CHEM LETT 2022. [DOI: 10.1016/j.cclet.2022.03.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Björkelund H, Gedda L, Malmqvist M, Andersson K. Resolving the EGF-EGFR interaction characteristics through a multiple-temperature, multiple-inhibitor, real-time interaction analysis approach. Mol Clin Oncol 2012; 1:343-352. [PMID: 24649173 DOI: 10.3892/mco.2012.37] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 10/19/2012] [Indexed: 01/15/2023] Open
Abstract
Overexpression and aberrant activity of the epidermal growth factor (EGF) have been observed in various cancer types, rendering it an important target in oncology research. The interaction between EGF and its receptor (EGFR), as well as subsequent internalization, is complex and may be affected by various factors including tyrosine kinase inhibitors (TKIs). By combining real-time binding curves produced in LigandTracer® with internalization assays conducted at different temperatures and with different TKIs, the processes of ligand binding, internalization and excretion was visualized. SKOV3 cells had a slower excretion rate compared to A431 and U343 cells, and the tested TKIs (gefitinib, lapatinib, AG1478 and erlotinib) reduced the degree of internalization. The kinetic analysis of the binding curves further demonstrated TKI-dependent balances of EGFR monomer and dimer populations, where lapatinib promoted the monomeric form, while the other TKIs induced dimers. The dimer levels were found to be associated with the apparent affinity of the EGF-EGFR interaction, with EGF binding stronger to EGFR dimers compared to monomers. This study analyzed how real-time molecular interaction analysis may be utilized in combination with perturbations in order to understand the kinetics of a ligand-receptor interaction, as well as some of its associated intracellular processes. Our multiple-temperature and -inhibitor assay setup renders it possible to follow the EGFR monomer, dimer and internalized populations in a detailed manner, allowing for a new perspective of the EGFR biology.
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Affiliation(s)
- Hanna Björkelund
- Biomedical Radiation Sciences, Department of Radiology, Oncology and Radiation Sciences, Rudbeck Laboratory, Uppsala University; ; Ridgeview Instruments AB, Uppsala
| | - Lars Gedda
- Biomedical Radiation Sciences, Department of Radiology, Oncology and Radiation Sciences, Rudbeck Laboratory, Uppsala University; ; Swedish Radiation Safety Authority, Stockholm
| | - Magnus Malmqvist
- Biomedical Radiation Sciences, Department of Radiology, Oncology and Radiation Sciences, Rudbeck Laboratory, Uppsala University; ; Ridgeview Instruments AB, Uppsala; ; Ridgeview Diagnostics AB c/o Bioventia AB, Uppsala, Sweden
| | - Karl Andersson
- Biomedical Radiation Sciences, Department of Radiology, Oncology and Radiation Sciences, Rudbeck Laboratory, Uppsala University; ; Ridgeview Instruments AB, Uppsala; ; Ridgeview Diagnostics AB c/o Bioventia AB, Uppsala, Sweden
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Björkelund H, Gedda L, Andersson K. Comparing the epidermal growth factor interaction with four different cell lines: intriguing effects imply strong dependency of cellular context. PLoS One 2011; 6:e16536. [PMID: 21304974 PMCID: PMC3031572 DOI: 10.1371/journal.pone.0016536] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Accepted: 12/19/2010] [Indexed: 02/07/2023] Open
Abstract
The interaction of the epidermal growth factor (EGF) with its receptor (EGFR) is known to be complex, and the common over-expression of EGF receptor family members in a multitude of tumors makes it important to decipher this interaction and the following signaling pathways. We have investigated the affinity and kinetics of (125)I-EGF binding to EGFR in four human tumor cell lines, each using four culturing conditions, in real time by use of LigandTracer®.Highly repeatable and precise measurements show that the overall apparent affinity of the (125)I-EGF - EGFR interaction is greatly dependent on cell line at normal culturing conditions, ranging from K(D) ≈ 200 pM on SKBR3 cells to K(D)≈8 nM on A431 cells. The (125)I-EGF - EGFR binding curves (irrespective of cell line) have strong signs of multiple simultaneous interactions. Furthermore, for the cell lines A431 and SKOV3, gefitinib treatment increases the (125)I-EGF - EGFR affinity, in particular when the cells are starved. The (125)I-EGF - EGFR interaction on cell line U343 is sensitive to starvation while as on SKBR3 it is insensitive to gefitinib and starvation.The intriguing pattern of the binding characteristics proves that the cellular context is important when deciphering how EGF interacts with EGFR. From a general perspective, care is advisable when generalizing ligand-receptor interaction results across multiple cell-lines.
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RNA helicase A is a DNA-binding partner for EGFR-mediated transcriptional activation in the nucleus. Proc Natl Acad Sci U S A 2010; 107:16125-30. [PMID: 20802156 DOI: 10.1073/pnas.1000743107] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
EGF induces the translocation of EGF receptor (EGFR) from the cell surface to the nucleus where EGFR activates gene transcription through its binding to an AT-rich sequence (ATRS) of the target gene promoter. However, how EGFR, without a DNA-binding domain, can bind to the gene promoter is unclear. In the present study, we show that RNA helicase A (RHA) is an important mediator for EGFR-induced gene transactivation. EGF stimulates the interaction of EGFR with RHA in the nucleus of cancer cells. The EGFR/RHA complex then associates with the target gene promoter through binding of RHA to the ATRS of the target gene promoter to activate its transcription. Knockdown of RHA expression in cancer cells abrogates the binding of EGFR to the target gene promoter, thereby reducing EGF/EGFR-induced gene expression. In addition, interruption of EGFR-RHA interaction decreases the EGFR-induced promoter activity. Consistently, we observed a positive correlation of the nuclear expression of EGFR, RHA, and cyclin D1 in human breast cancer samples. These results indicate that RHA is a DNA-binding partner for EGFR-mediated transcriptional activation in the nucleus.
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Björkelund H, Gedda L, Andersson K. Avoiding false negative results in specificity analysis of protein-protein interactions. J Mol Recognit 2010; 24:81-9. [DOI: 10.1002/jmr.1026] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Abstract
For the treatment of minimum residual diseases such micrometastases and residual tumor margins that remain after debulking of the primary tumor, targeted radiotherapy using radiopharmaceuticals tagged with alpha-particle-emitting radionuclides is very attractive. In addition to the their short range in tissue, which helps minimize harmful effects on adjacent normal tissues, alpha-particles, being high LET radiation, have several radiobiological advantages. The heavy halogen, astatine-211 is one of the prominent alpha-particle-emitting radionuclides in practice. Being a halogen, it can often be incorporated into biomolecules of interest by adapting radioiodination chemistry. A wide spectrum of compounds from the simple [(211)At]astatide ion to small organic molecules, peptides, and large proteins labeled with (211)At have been investigated with at least two reaching the stage of clinical evaluation. The chemistry, cytotoxic advantages, biodistribution studies, and microdosimetry/pharmacokinetic modeling of some of these agents will be reviewed. In addition, potential problems such as the harmful effect of radiolysis on the synthesis, lack of sufficient in vivo stability of astatinated compounds, and possible adverse effects when they are systemically administered will be discussed.
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Affiliation(s)
- Ganesan Vaidyanathan
- Department of Radiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Michael R. Zalutsky
- Department of Radiology, Duke University Medical Center, Durham, North Carolina, USA
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Andersson U, Johansson D, Behnam-Motlagh P, Johansson M, Malmer B. Treatment schedule is of importance when gefitinib is combined with irradiation of glioma and endothelial cells in vitro. Acta Oncol 2008; 46:951-60. [PMID: 17917826 DOI: 10.1080/02841860701253045] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Amplified epidermal growth factor receptor (EGFR) signaling is supposed to contribute to clinical radiation resistance of glioblastoma multiforme (GBM). Therefore, inhibition of EGFR signaling pathways by the selective EGFR tyrosine kinase inhibitor, gefitinib (ZD1839, Iressa), may increase the therapeutic effects of radiotherapy. The effects of different schedules for administration of gefitinib on sensitivity to irradiation of the human glioma cell lines (251MG and SF-767), a rat glioma cell line (BT4C), and an immortalized rat brain endothelial cell line (RBE4) is reported. Differences in effects of the combined treatment on cell toxicity were determined by a fluorometric cytotoxicity assay, and nuclear DNA fragmentation was used for quantification of apoptosis. Pre-administration with gefitinib for 30 min prior to irradiation followed by continuous incubation with gefitinib significantly increased the cytotoxicity of SF-767, BT4C, and RBE4 cells. However, the human glioma cell line 251MG was protected against radiation-induced damage by this treatment schedule, at lower concentrations of gefitinib. Pre-administration with gefitinib for 24 h prior to irradiation without following incubation with gefitinib increased the cytotoxicity of SF-767 and BT4C cells. Post-irradiation treatment with gefitinib significantly increased the cytotoxicity in all cell lines except for 251MG. We demonstrated heterogeneity in the cytotoxic effects of gefitinib between cell lines. Response to gefitinib might be due to other mechanisms than through the EGF receptor as some of the cell lines showed sensitivity to gefitinib despite no or low expression of EGFR. This study also demonstrates the importance of timing of gefitinib administration when this agent is combined with irradiation.
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Almqvist Y, Steffen AC, Lundqvist H, Jensen H, Tolmachev V, Sundin A. Biodistribution of 211At-labeled humanized monoclonal antibody A33. Cancer Biother Radiopharm 2007; 22:480-7. [PMID: 17803442 DOI: 10.1089/cbr.2007.349a] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Radioimmunotherapy (RIT) could be a possible adjuvant treatment method for patients with colorectal carcinoma. The A33 antigen is a promising RIT target, as it is highly and homogenously expressed in 95% of all colorectal carcinomas. In this study, the humanized monoclonal antibody A33 (huA33), targeting the A33 antigen, was labeled with the therapeutic nuclide 211At, and the biodistribution and in vivo targeting ability of the conjugate was investigated in an athymic mouse xenograft model. There was an accumulation of 211At in tumor tissue over time, but no substantial accumulation was seen in any organ apart from the skin and thyroid, indicating no major release of free 211At in vivo. At all time points, the uptake of 211At-huA33 was higher in tumor tissue than in most organs, and at 8 hours postinjection (p.i.), no organ had a higher uptake than tumor tissue. The tumor-to-blood ratio of 211At-huA33 increased with time, reaching 2.5 after 21 hours p.i. The highest absorbed dose was found in the blood, but the tumor received a higher dose than any organ other than the thyroid. An in vivo blocking experiment showed that 211At-huA33 binds specifically to human tumor xenografts in athymic mice. In conclusion, the favorable biodistribution and specific in vivo targeting ability of 211At-huA33 makes it a potential therapeutic agent for the RIT of metastatic colorectal carcinoma.
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Affiliation(s)
- Ylva Almqvist
- Unit of Radiology, Department of Oncology, Radiology, and Clinical Immunology, Uppsala University, Sweden, and Department of Clinical Physiology and Nuclear Medicine, PET and Cyclotron Unit, Rigshospitalet, Copenhagen, Denmark.
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Boswell CA, Brechbiel MW. Development of radioimmunotherapeutic and diagnostic antibodies: an inside-out view. Nucl Med Biol 2007; 34:757-78. [PMID: 17921028 PMCID: PMC2212602 DOI: 10.1016/j.nucmedbio.2007.04.001] [Citation(s) in RCA: 182] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Revised: 03/29/2007] [Accepted: 04/04/2007] [Indexed: 11/25/2022]
Abstract
Only a handful of radiolabeled antibodies (Abs) have gained US Food and Drug Administration (FDA) approval for use in clinical oncology, including four immunodiagnostic agents and two targeted radioimmunotherapeutic agents. Despite the advent of nonimmunogenic Abs and the availability of a diverse library of radionuclides, progress beyond early Phase II radioimmunotherapy (RIT) studies in solid tumors has been marginal. Furthermore, [18F]fluorodeoxyglucose continues to dominate the molecular imaging domain, underscored by a decade-long absence of any newly approved Ab-based imaging agent (none since 1996). Why has the development of clinically successful Abs for RIT been limited to lymphoma? What obstacles must be overcome to allow the FDA approval of immuno-positron emission tomography (immuno-PET) imaging agents? How can we address the unique challenges that have thus far prevented the introduction of Ab-based imaging agents and therapeutics for solid tumors? Many poor decisions have been made regarding radiolabeled Abs, but useful insight can be gained from these mistakes. The following review addresses the physical, chemical, biological, clinical, regulatory and financial limitations that impede the progress of this increasingly important class of drugs.
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Affiliation(s)
- C. Andrew Boswell
- Radioimmune & Inorganic Chemistry Section, Radiation Oncology Branch, National Cancer Institute, Building 10 Center Drive, Bethesda, Maryland, 20892-1088
| | - Martin W. Brechbiel
- Radioimmune & Inorganic Chemistry Section, Radiation Oncology Branch, National Cancer Institute, Building 10 Center Drive, Bethesda, Maryland, 20892-1088
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Carlsson J, Ren ZP, Wester K, Sundberg AL, Heldin NE, Hesselager G, Persson M, Gedda L, Tolmachev V, Lundqvist H, Blomquist E, Nistér M. Planning for intracavitary anti-EGFR radionuclide therapy of gliomas. Literature review and data on EGFR expression. J Neurooncol 2006; 77:33-45. [PMID: 16200342 DOI: 10.1007/s11060-005-7410-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Targeting with radionuclide labelled substances that bind specifically to the epidermal growth factor receptor, EGFR, is considered for intracavitary therapy of EGFR-positive glioblastoma multiforme, GBM. Relevant literature is reviewed and examples of EGFR expression in GBM are given. The therapeutical efforts made so far using intracavitary anti-tenascin radionuclide therapy of GBM have given limited effects, probably due to low radiation doses to the migrating glioma cells in the brain. Low radiation doses might be due to limited penetration of the targeting agents or heterogeneity in the expression of the target structure. In this article we focus on the possibilities to target EGFR on the tumour cells instead of an extracellular matrix component. There seems to be a lack of knowledge on the degree of intratumoral variation of EGFR expression in GBM, although the expression seemed rather homogeneous over large areas in most of the examples (n=16) presented from our laboratory. The observed homogeneity was surprising considering the genomic instability and heterogeneity that generally characterises highly malignant tumours. However, overexpression of EGFR is, at least in primary GBMs, one of the steps in the development of malignancy, and tumour cells that lose or downregulate EGFR will probably be outgrown in an expanding tumour cell population. Thus, loss of EGFR expression might not be the critical factor for successful intracavitary radionuclide therapy. Instead, it is likely that the penetration properties of the targeting agents are critical, and detailed studies on this are urgent.
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Affiliation(s)
- J Carlsson
- Unit of Biomedical Radiation Sciences, Department of Oncology, Radiology and Clinical Immunology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden.
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Carlsson J, Eriksson V, Stenerlöw B, Lundqvist H. Requirements regarding dose rate and exposure time for killing of tumour cells in beta particle radionuclide therapy. Eur J Nucl Med Mol Imaging 2006; 33:1185-95. [PMID: 16718515 PMCID: PMC1998878 DOI: 10.1007/s00259-006-0109-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2005] [Accepted: 02/26/2006] [Indexed: 10/25/2022]
Abstract
PURPOSE The purpose of this study was to identify combinations of dose rate and exposure time that have the potential to provide curative treatment with targeted radionuclide therapy applying low dose rate beta irradiation. METHODS Five tumour cell lines, U-373MG and U-118MG gliomas, HT-29 colon carcinoma, A-431 cervical squamous carcinoma and SKBR-3 breast cancer, were used. An experimental model with 10(5) tumour cells in each sample was irradiated with low dose rate beta particles. The criterion for successful treatment was absence of recovery of cells during a follow-up period of 3 months. The initial dose rates were in the range 0.1-0.8 Gy/h, and the cells were continuously exposed for 1, 3 or 7 days. These combinations covered dose rates and doses achievable in targeted radionuclide therapy. RESULTS Continuous irradiation with dose rates of 0.2-0.3 and 0.4-0.6 Gy/h for 7 and 3 days, respectively, could kill all cells in each tumour cell sample. These treatments gave total radiation doses of 30-40 Gy. However, when exposed for just 24 h with about 0.8 Gy/h, only the SKBR-3 cells were successfully treated; all the other cell types recovered. There were large cell type-dependent variations in the growth delay patterns for the cultures that recovered. The U-118MG cells were most resistant and the U-373MG and SKBR-3 cells most sensitive to the treatments. The HT-29 and A-431 cells were intermediate. CONCLUSION The results serve as a guideline for the combinations of dose rate and exposure time necessary to kill tumour cells when applying low dose rate beta irradiation. The shift from recovery to "cure" fell within a narrow range of dose rate and exposure time combinations.
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Affiliation(s)
- Jörgen Carlsson
- Division of Biomedical Radiation Sciences, Department of Oncology, Radiology and Clinical Immunology, Rudbeck Laboratory, Uppsala University, SE-751 85, Uppsala, Sweden.
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Mume E, Orlova A, Malmström PU, Lundqvist H, Sjöberg S, Tolmachev V. Radiobromination of humanized anti-HER2 monoclonal antibody trastuzumab using N-succinimidyl 5-bromo-3-pyridinecarboxylate, a potential label for immunoPET. Nucl Med Biol 2006; 32:613-22. [PMID: 16026708 DOI: 10.1016/j.nucmedbio.2005.04.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2005] [Revised: 04/17/2005] [Accepted: 04/17/2005] [Indexed: 11/24/2022]
Abstract
Combining the specificity of radioimmunoscintigraphy and the high sensitivity of PET in an in vivo detection technique could improve the quality of nuclear diagnostics. Positron-emitting nuclide (76)Br (T(1/2)=16.2 h) might be a possible candidate for labeling monoclonal antibodies (mAbs) and their fragments, provided that the appropriate labeling chemistry has been established. For internalizing antibodies, such as the humanized anti-HER2 monoclonal antibody, trastuzumab, radiobromine label should be residualizing, i.e., ensuring that radiocatabolites are trapped intracellularly after the proteolytic degradation of antibody. This study evaluated the chemistry of indirect radiobromination of trastuzumab using N-succinimidyl 5-(tributylstannyl)-3-pyridinecarboxylate. Literature data indicated that the use of this method provided residualizing properties for iodine and astatine labels on some antibodies. An optimized "one-pot" procedure produced an overall labeling efficiency of 45.5+/-1.2% over 15 min. The bromine label was stable under physiological and denaturing conditions. The labeled trastuzumab retained its capacity to bind specifically to HER2-expressing SKOV-3 ovarian carcinoma cells in vitro (immunoreactivity more than 75%). However, in vitro cell test did not demonstrate that the radiobromination of trastuzumab using N-succinimidyl 5-bromo-3-pyridinecarboxylate improves cellular retention of radioactivity in comparison with the use of N-succinimidyl 4-bromobenzoate.
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Affiliation(s)
- Eskender Mume
- Organic Chemistry, Department of Chemistry, Uppsala University, S-751 24 Uppsala, Sweden
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Björke H, Andersson K. Measuring the affinity of a radioligand with its receptor using a rotating cell dish with in situ reference area. Appl Radiat Isot 2006; 64:32-7. [PMID: 16055339 DOI: 10.1016/j.apradiso.2005.06.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2005] [Revised: 06/03/2005] [Accepted: 06/06/2005] [Indexed: 10/25/2022]
Abstract
This report describes a semi-automated method for the measurement of affinity of radiolabeled ligands interacting with cell-surface receptors on intact cancer cells. The method saves labor time and reagents compared to common manual measurements. A complete affinity measurement can be performed in one cell dish by using a target cell area and a reference area and repeatedly measure the differential activity (i.e. target activity-reference activity). The affinities obtained for different ligand-receptor interactions agreed with affinities reported in the literature.
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Affiliation(s)
- Henrik Björke
- Division of Biomedical Radiation Sciences, Uppsala University, Sweden
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Lee FT, Mountain AJ, Kelly MP, Hall C, Rigopoulos A, Johns TG, Smyth FE, Brechbiel MW, Nice EC, Burgess AW, Scott AM. Enhanced Efficacy of Radioimmunotherapy with 90Y-CHX-A″-DTPA-hu3S193 by Inhibition of Epidermal Growth Factor Receptor (EGFR) Signaling with EGFR Tyrosine Kinase Inhibitor AG1478. Clin Cancer Res 2005; 11:7080s-7086s. [PMID: 16203806 DOI: 10.1158/1078-0432.ccr-1004-0019] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Monoclonal antibodies and tyrosine kinase inhibitors specific for the epidermal growth factor receptor (EGFR) have been shown to enhance the effect of external beam radiation on EGFR-positive tumors. The effect of EGFR signaling abrogation by EGFR tyrosine kinase inhibitor on the efficacy of radioimmunotherapy has not been reported previously. This study investigated the effect of EGFR tyrosine kinase inhibition on the efficacy of radioimmunotherapy in a human cancer xenograft model. EXPERIMENTAL DESIGN The humanized anti-Lewis Y antibody hu3S193 and the EGFR tyrosine kinase inhibitor AG1478 were studied. BALB/c nude mice were engrafted with A431 squamous carcinoma cells. Initial biodistribution properties of the 90Y-CHX-A''-DTPA-hu3S193 were evaluated in this model. In therapy experiments, cohorts of four to five xenografted mice were treated with saline as placebo, 0.4 mg AG1478 i.p. (six doses over 2 weeks), single i.v. injections of unlabeled hu3S193, or 90Y-CHX-A''-DTPA-hu3S193 (12.5, 25, 50, or 100 microCi). The combination of 0.4 mg AG1478 i.p. and 25 microCi 90Y-CHX-A''-DTPA-hu3S193 i.v. was subsequently evaluated in the A431 model. RESULTS 90Y-CHX-A''-DTPA-hu3S193 retained excellent immunoreactivity after radiolabeling. The biodistribution study showed excellent uptake in tumor (90.33 +/- 38.84%ID/g) peaking at 24 to 72 hours after injection and with prolonged retention. 90Y-CHX-A''-DTPA-hu3S193 significantly inhibited A431 xenograft growth at 25, 50, and 100 microCi doses. The combination of 0.4 mg AG1478 with a single dose of 25 microCi 90Y-CHX-A''-DTPA-hu3S193 resulted in a significant enhancement of efficacy compared with either agent alone (P = 0.013). CONCLUSIONS The efficacy of radioimmunotherapy with 90Y-CHX-A''-DTPA-hu3S193 is significantly enhanced by EGFR tyrosine kinase inhibitor AG1478. Further investigations of dosing regimens using EGFR tyrosine kinase inhibitors and radioimmunotherapy in the treatment of EGFR expressing tumors are warranted.
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Affiliation(s)
- Fook T Lee
- Tumour Targeting Program, Ludwig Institute for Cancer Research, Austin Hospital, Heidelberg, Victoria, Australia
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Steffen AC, Wikman M, Tolmachev V, Adams GP, Nilsson FY, Ståhl S, Carlsson J. In vitro characterization of a bivalent anti-HER-2 affibody with potential for radionuclide-based diagnostics. Cancer Biother Radiopharm 2005; 20:239-48. [PMID: 15989469 DOI: 10.1089/cbr.2005.20.239] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The 185 kDa transmembrane glycoprotein human epidermal growth factor receptor 2 (HER-2) (p185/neu, c-ErbB-2) is overexpressed in breast and ovarian cancers. Overexpression in breast cancer correlates with poor patient prognosis, and visualization of HER-2 expression might provide valuable diagnostic information influencing patient management. We have previously described the generation of a new type of affinity ligand, a 58-amino-acid affibody (Z(HER2:4)) with specific binding to HER-2. In order to benefit from avidity effects, we have created a bivalent form of the affibody ligand, (Z(HER2:4))2. The monovalent and bivalent ligands were compared in various assays. The new bivalent affibody has a molecular weight of 15.6 kDa and an apparent affinity (K(D)) against HER-2 of 3 nM. After radioiodination, using the linker molecule N-succinimidyl p-(trimethylstannyl) benzoate (SPMB), in vitro binding assays showed specific binding to HER-2 overexpressing cells. Internalization of 125I was shown after delivery with both the monovalent and the bivalent affibody. The cellular retention of 125I was longer after delivery with the bivalent affibody when compared to delivery with the monovalent affibody. With approximately the same affinity as the monoclonal antibody trastuzumab (Herceptin) but only one tenth of the size, this new bivalent molecule is a promising candidate for radionuclide-based detection of HER-2 expression in tumors. 125I was used in this study as a surrogate marker for the diagnostically relevant radioisotopes 123I for single photon emission computed tomography (SPECT)/gamma-camera imaging and 124I for positron emission tomography (PET).
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Affiliation(s)
- Ann-Charlott Steffen
- Unit of Biomedical Radiation Sciences, Department of Oncology, Radiology and Clinical Immunology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden.
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Cornelissen B, Kersemans V, Jans L, Staelens L, Oltenfreiter R, Thonissen T, Achten E, Slegers G. Comparison between 1 T MRI and non-MRI based volumetry in inoculated tumours in mice. Br J Radiol 2005; 78:338-42. [PMID: 15774595 DOI: 10.1259/bjr/20260420] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Tumour volume is an important therapeutic endpoint for mouse tumour models in the evaluation of new chemotherapeutic drugs and in pre-clinical evaluation of new radioimmunotherapy pharmaceuticals. In this study, two 1 T MRI-based methods both using T1-T2 hybrid weighting, a manual method (determination of the area per slice) and a semi-automated method (using thresholding), are compared with two classical methods, the abovementioned calliper method and volumetry by water displacement after dissection of the tumour. Interoperator and intraoperator differences for both MRI-based methods were good (no differences p<0.05 using a repeated measures analysis of variance (ANOVA) test). Correlation between the different methods was excellent. No significant differences were obtained (p<0.05), except for the semi-automated method, because it automatically excludes necrotic regions from the tumour. Therefore, we conclude that both manual and semi-automated tumour volumetry in subcutaneous tumour bearing athymic mice by low-field MRI are accurate and reliable methods. The semi-automated method is especially useful for larger tumour volumes, since it accounts for necrotic areas within the tumour.
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Affiliation(s)
- B Cornelissen
- Laboratory of Radiopharmacy, Ghent University, Harelbekestraat 72, B-9000 Gen, Belgium
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Lindencrona U, Sillfors-Elverby L, Nilsson M, Forssell-Aronsson E. Adsorption and volatility of free 211At and 125I-. Appl Radiat Isot 2005; 62:395-403. [PMID: 15607915 DOI: 10.1016/j.apradiso.2004.07.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2004] [Accepted: 07/20/2004] [Indexed: 11/17/2022]
Abstract
The present study was undertaken to extend our knowledge of the behaviour of 211At in the laboratory environment. An unexpectedly high volatility of free 211At was found, up to 85% during an hour. Free 211At also adsorbed more onto the plastic material studied than 125I-. The results of this study show that it is of great importance to pay careful attention to radiation protection procedures during the practical handling of free 211At.
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Affiliation(s)
- Ulrika Lindencrona
- Department of Radiation Physics, Göteborg University, Sahlgrenska University Hospital, SE-413 45 Göteborg, Sweden.
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