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Efforts toward PET-Activatable Red-Shifted Silicon Rhodamines and Silicon Pyronine Dyes. Pharmaceuticals (Basel) 2023; 16:ph16030401. [PMID: 36986500 PMCID: PMC10053042 DOI: 10.3390/ph16030401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 02/14/2023] [Accepted: 02/18/2023] [Indexed: 03/09/2023] Open
Abstract
Tracers for bimodal optical imaging and positron emission tomography unite multiple advantages in a single molecule. Their tumor-specific uptake can be visualized after their PET activation by radiofluorination via PET/CT or PET/MRI allowing for staging or therapy planning, while their non-radioactive moiety additionally facilitates the visualization of malignant tissue during intraoperative fluorescence-guided surgery or in histological assessments. The silicon-bridged xanthene core offers the opportunity for radiofluorination with SiFA isotope exchange to obtain a small-molecule, PET-activatable NIR dye that can be linked to different target vectors. Herein, we demonstrate for the first time the PET-activation of a fluorinated silicon pyronine, belonging to a class of low-molecular-weight fluorescence dyes with a large Stokes shift (up to 129 nm) and solvent-dependent NIR dye properties, with a successful radiochemical conversion of 70%. The non-fluorinated pyronine precursor is easily accessible by a three-step sequence from commercially starting material with a 12% overall yield. Moreover, a library of seven unusually functionalized (by approximately 15 nm), red-shifted silicon rhodamines were synthesized in three- to four-step sequences and the optical properties of the novel dyes were characterized. It was also shown that the synthesized silicon rhodamine dyes can be easily conjugated by amide bond formation or ‘click-reaction’ approaches.
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2
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Yi X, Wang Z, Hu X, Yu A. Affinity probes based on small-molecule inhibitors for tumor imaging. Front Oncol 2022; 12:1028493. [PMID: 36387103 PMCID: PMC9647038 DOI: 10.3389/fonc.2022.1028493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 10/17/2022] [Indexed: 11/29/2022] Open
Abstract
Methods for molecular imaging of target areas, including optical imaging, radionuclide imaging, magnetic resonance imaging and other imaging technologies, are helpful for the early diagnosis and precise treatment of cancers. In addition to cancer management, small-molecule inhibitors are also used for developing cancer target probes since they act as the tight-binding ligands of overexpressed proteins in cancer cells. This review aims to summarize the structural designs of affinity probes based on small-molecule inhibitors from the aspects of the inhibitor, linker, dye and radionuclide, and discusses the influence of the modification of these structures on affinity and pharmacokinetics. We also present examples of inhibitor affinity probes in clinical applications, and these summaries will provide insights for future research and clinical translations.
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Affiliation(s)
| | | | - Xiang Hu
- *Correspondence: Aixi Yu, ; Xiang Hu,
| | - Aixi Yu
- *Correspondence: Aixi Yu, ; Xiang Hu,
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Takematsu M, Umezawa M, Sera T, Kitagawa Y, Kurahashi H, Yamada S, Okubo K, Kamimura M, Yokota H, Soga K. Influence of the difference in refractive index on the interface of an object and the surroundings in near-infrared fluorescence tomography. APPLIED OPTICS 2022; 61:638-644. [PMID: 35200907 DOI: 10.1364/ao.445357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 12/03/2021] [Indexed: 06/14/2023]
Abstract
The refraction of fluorescence from the inside of a sample at the surface results in fluctuations in fluorescence computed tomography (CT). We evaluated the influence of the difference in refractive index (RI) between the sample body and the surroundings on fluorescence CT results. The brightest fluorescent point is away from the correct point on the tomograms owing to the refraction. The speculated position is determined as the exact point if the RI ratio ranges between 0.97 and 1.03 by immersing the body in an RI matching liquid. The results can help in experimental settings of fluorescence CT for acquiring three-dimensional positional information.
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Ariztia J, Solmont K, Moïse NP, Specklin S, Heck MP, Lamandé-Langle S, Kuhnast B. PET/Fluorescence Imaging: An Overview of the Chemical Strategies to Build Dual Imaging Tools. Bioconjug Chem 2022; 33:24-52. [PMID: 34994545 DOI: 10.1021/acs.bioconjchem.1c00503] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Molecular imaging is a biomedical research discipline that has quickly emerged to afford the observation, characterization, monitoring, and quantification of biomarkers and biological processes in living organism. It covers a large array of imaging techniques, each of which provides anatomical, functional, or metabolic information. Multimodality, as the combination of two or more of these techniques, has proven to be one of the best options to boost their individual properties, hence offering unprecedented tools for human health. In this review, we will focus on the combination of positron emission tomography and fluorescence imaging from the specific perspective of the chemical synthesis of dual imaging agents. Based on a detailed analysis of the literature, this review aims at giving a comprehensive overview of the chemical strategies implemented to build adequate imaging tools considering radiohalogens and radiometals as positron emitters, fluorescent dyes mostly emitting in the NIR window and all types of targeting vectors.
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Affiliation(s)
- Julen Ariztia
- Université Paris-Saclay, Inserm, CNRS, CEA, Laboratoire d'Imagerie Biomédicale Multimodale Paris-Saclay, 91401, Orsay, France
| | - Kathleen Solmont
- Université Paris-Saclay, Inserm, CNRS, CEA, Laboratoire d'Imagerie Biomédicale Multimodale Paris-Saclay, 91401, Orsay, France
| | | | - Simon Specklin
- Université Paris-Saclay, Inserm, CNRS, CEA, Laboratoire d'Imagerie Biomédicale Multimodale Paris-Saclay, 91401, Orsay, France
| | - Marie Pierre Heck
- Université Paris-Saclay, INRAE, Département Médicaments et Technologies pour la santé (DMTS), SCBM, 91191, Gif-sur-Yvette cedex, France
| | | | - Bertrand Kuhnast
- Université Paris-Saclay, Inserm, CNRS, CEA, Laboratoire d'Imagerie Biomédicale Multimodale Paris-Saclay, 91401, Orsay, France
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5
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Woźniak M, Konopka CJ, Płoska A, Hedhli J, Siekierzycka A, Banach M, Bartoszewski R, Dobrucki LW, Kalinowski L, Dobrucki IT. Molecularly targeted nanoparticles: an emerging tool for evaluation of expression of the receptor for advanced glycation end products in a murine model of peripheral artery disease. Cell Mol Biol Lett 2021; 26:10. [PMID: 33726678 PMCID: PMC7968326 DOI: 10.1186/s11658-021-00253-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 03/02/2021] [Indexed: 12/15/2022] Open
Abstract
Background Molecular imaging with molecularly targeted probes is a powerful tool for studying the spatio-temporal interactions between complex biological processes. The pivotal role of the receptor for advanced glycation end products (RAGE), and its involvement in numerous pathological processes, aroused the demand for RAGE-targeted imaging in various diseases. In the present study, we evaluated the use of a diagnostic imaging agent for RAGE quantification in an animal model of peripheral artery disease, a multimodal dual-labeled probe targeted at RAGE (MMIA-CML). Methods PAMAM dendrimer was conjugated with Nε-carboxymethyl-lysine (CML) modified albumin to synthesize the RAGE-targeted probe. A control untargeted agent carried native non-modified human albumin (HSA). Bifunctional p-SCN-Bn-NOTA was used to conjugate the 64Cu radioisotope. Surgical right femoral artery ligation was performed on C57BL/6 male mice. One week after femoral artery ligation, mice were injected with MMIA-CML or MMIA-HSA labeled with 64Cu radioisotope and 60 min later in vivo microPET-CT imaging was performed. Immediately after PET imaging studies, the murine hindlimb muscle tissues were excised and prepared for gene and protein expression analysis. RAGE gene and protein expression was assessed using real-time qPCR and Western blot technique respectively. To visualize RAGE expression in excised tissues, microscopic fluorescence imaging was performed using RAGE-specific antibodies and RAGE-targeted and -control MMIA. Results Animals subjected to PET imaging exhibited greater MMIA-CML uptake in ischemic hindlimbs than non-ischemic hindlimbs. We observed a high correlation between fluorescent signal detection and radioactivity measurement. Significant RAGE gene and protein overexpression were observed in ischemic hindlimbs compared to non-ischemic hindlimbs at one week after surgical ligation. Fluorescence microscopic staining revealed significantly increased uptake of RAGE-targeted nanoparticles in both ischemic and non-ischemic muscle tissues compared to the control probe but at a higher level in ischemic hindlimbs. Ischemic tissue exhibited explicit RAGE dyeing following anti-RAGE antibody and high colocalization with the MMIA-CML targeted at RAGE. Conclusions The present results indicate increased expression of RAGE in the ischemic hindlimb and enable the use of multimodal nanoparticles in both in vitro and in vivo experimental models, creating the possibility for imaging structural and functional changes with a RAGE-targeted tracer. Supplementary Information The online version contains supplementary material available at 10.1186/s11658-021-00253-0.
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Affiliation(s)
- Marcin Woźniak
- Department of Medical Laboratory Diagnostics - Fahrenheit Biobank BBMRI.pl, Medical University of Gdansk, 7 Debinki Street, 80-211, Gdansk, Poland.,University of Illinois at Urbana-Champaign Beckman Institute for Advanced Science and Technology, 405 N Mathews Ave, MC-251, 61801 Urbana, IL, USA
| | - Christian J Konopka
- University of Illinois at Urbana-Champaign Beckman Institute for Advanced Science and Technology, 405 N Mathews Ave, MC-251, 61801 Urbana, IL, USA.,Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Agata Płoska
- Department of Medical Laboratory Diagnostics - Fahrenheit Biobank BBMRI.pl, Medical University of Gdansk, 7 Debinki Street, 80-211, Gdansk, Poland.,Biobanking and Biomolecular Resources Research Infrastructure Poland (BBMRI.pl), Gdansk, Poland
| | - Jamila Hedhli
- University of Illinois at Urbana-Champaign Beckman Institute for Advanced Science and Technology, 405 N Mathews Ave, MC-251, 61801 Urbana, IL, USA
| | - Anna Siekierzycka
- Department of Medical Laboratory Diagnostics - Fahrenheit Biobank BBMRI.pl, Medical University of Gdansk, 7 Debinki Street, 80-211, Gdansk, Poland
| | - Maciej Banach
- Department of Hypertension, Medical University of Lodz, Lodz, Poland
| | - Rafal Bartoszewski
- Department of Biology and Pharmaceutical Botany, Medical University of Gdansk, Gdansk, Poland
| | - Lawrence W Dobrucki
- Department of Medical Laboratory Diagnostics - Fahrenheit Biobank BBMRI.pl, Medical University of Gdansk, 7 Debinki Street, 80-211, Gdansk, Poland.,University of Illinois at Urbana-Champaign Beckman Institute for Advanced Science and Technology, 405 N Mathews Ave, MC-251, 61801 Urbana, IL, USA.,Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Biobanking and Biomolecular Resources Research Infrastructure Poland (BBMRI.pl), Gdansk, Poland.,Cancer Center at Illinois, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Carle-Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Leszek Kalinowski
- Department of Medical Laboratory Diagnostics - Fahrenheit Biobank BBMRI.pl, Medical University of Gdansk, 7 Debinki Street, 80-211, Gdansk, Poland. .,Biobanking and Biomolecular Resources Research Infrastructure Poland (BBMRI.pl), Gdansk, Poland. .,BioTechMed Centre, Department of Mechanics of Materials and Structures, Gdansk University of Technology, Gdansk, Poland.
| | - Iwona T Dobrucki
- University of Illinois at Urbana-Champaign Beckman Institute for Advanced Science and Technology, 405 N Mathews Ave, MC-251, 61801 Urbana, IL, USA. .,Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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Chen KT, Nieuwenhuizen J, Handula M, Seimbille Y. A novel clickable MSAP agent for dual fluorescence/nuclear labeling of biovectors. Org Biomol Chem 2020; 18:6134-6139. [DOI: 10.1039/d0ob01222j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Simple and efficient synthesis of dual-modality imaging agents for preoperative surgical planning and intraoperative surgical guidance.
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Affiliation(s)
- Kuo-Ting Chen
- Erasmus MC
- University Medical Center Rotterdam
- Department of Radiology and Nuclear Medicine
- Rotterdam
- The Netherlands
| | - Jim Nieuwenhuizen
- Erasmus MC
- University Medical Center Rotterdam
- Department of Radiology and Nuclear Medicine
- Rotterdam
- The Netherlands
| | - Maryana Handula
- Erasmus MC
- University Medical Center Rotterdam
- Department of Radiology and Nuclear Medicine
- Rotterdam
- The Netherlands
| | - Yann Seimbille
- Erasmus MC
- University Medical Center Rotterdam
- Department of Radiology and Nuclear Medicine
- Rotterdam
- The Netherlands
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7
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Targeting MMP-14 for dual PET and fluorescence imaging of glioma in preclinical models. Eur J Nucl Med Mol Imaging 2019; 47:1412-1426. [PMID: 31773232 DOI: 10.1007/s00259-019-04607-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 11/07/2019] [Indexed: 02/08/2023]
Abstract
PURPOSE There is a clinical need for agents that target glioma cells for non-invasive and intraoperative imaging to guide therapeutic intervention and improve the prognosis of glioma. Matrix metalloproteinase (MMP)-14 is overexpressed in glioma with negligible expression in normal brain, presenting MMP-14 as an attractive biomarker for imaging glioma. In this study, we designed a peptide probe containing a near-infrared fluorescence (NIRF) dye/quencher pair, a positron emission tomography (PET) radionuclide, and a moiety with high affinity to MMP-14. This novel substrate-binding peptide allows dual modality imaging of glioma only after cleavage by MMP-14 to activate the quenched NIRF signal, enhancing probe specificity and imaging contrast. METHODS MMP-14 expression and activity in human glioma tissues and cells were measured in vitro by immunofluorescence and gel zymography. Cleavage of the novel substrate and substrate-binding peptides by glioma cells in vitro and glioma xenograft tumors in vivo was determined by NIRF imaging. Biodistribution of the radiolabeled MMP-14-binding peptide or substrate-binding peptide was determined in mice bearing orthotopic patient-derived xenograft (PDX) glioma tumors by PET imaging. RESULTS Glioma cells with MMP-14 activity showed activation and retention of NIRF signal from the cleaved peptides. Resected mouse brains with PDX glioma tumors showed tumor-to-background NIRF ratios of 7.6-11.1 at 4 h after i.v. injection of the peptides. PET/CT images showed localization of activity in orthotopic PDX tumors after i.v. injection of 68Ga-binding peptide or 64Cu-substrate-binding peptide; uptake of the radiolabeled peptides in tumors was significantly reduced (p < 0.05) by blocking with the non-labeled-binding peptide. PET and NIRF signals correlated linearly in the orthotopic PDX tumors. Immunohistochemistry showed co-localization of MMP-14 expression and NIRF signal in the resected tumors. CONCLUSIONS The novel MMP-14 substrate-binding peptide enabled PET/NIRF imaging of glioma models in mice, warranting future image-guided resection studies with the probe in preclinical glioma models.
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8
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Microwave-Synthesized Platinum-Embedded Mesoporous Silica Nanoparticles as Dual-Modality Contrast Agents: Computed Tomography and Optical Imaging. Int J Mol Sci 2019; 20:ijms20071560. [PMID: 30925712 PMCID: PMC6480439 DOI: 10.3390/ijms20071560] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 03/25/2019] [Accepted: 03/25/2019] [Indexed: 11/16/2022] Open
Abstract
Nanoparticle-based imaging contrast agents have drawn tremendous attention especially in multi-modality imaging. In this study, we developed mesoporous silica nanoparticles (MSNs) for use as dual-modality contrast agents for computed tomography (CT) and near-infrared (NIR) optical imaging (OI). A microwave synthesis for preparing naked platinum nanoparticles (nPtNPs) on MSNs (MSNs-Pt) was developed and characterized with physicochemical analysis and imaging systems. The high density of nPtNPs on the surface of the MSNs could greatly enhance the CT contrast. Inductively coupled plasma mass spectrometry (ICP-MS) revealed the MSNs-Pt compositions to be ~14% Pt by weight and TEM revealed an average particle diameter of ~50 nm and covered with ~3 nm diameter nPtNPs. To enhance the OI contrast, the NIR fluorescent dye Dy800 was conjugated to the MSNs-Pt nanochannels. The fluorescence spectra of MSNs-Pt-Dy800 were very similar to unconjugated Dy800. The CT imaging demonstrated that even modest degrees of Pt labeling could result in substantial X-ray attenuation. In vivo imaging of breast tumor-bearing mice treated with PEGylated MSNs-Pt-Dy800 (PEG-MSNs-Pt-Dy800) showed significantly improved contrasts in both fluorescence and CT imaging and the signal intensity within the tumor retained for 24 h post-injection.
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9
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Perrin DM. Organotrifluoroborates as prosthetic groups for Single-Step F18-Labeling of Complex Molecules. Curr Opin Chem Biol 2018; 45:86-94. [DOI: 10.1016/j.cbpa.2018.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 02/23/2018] [Accepted: 03/07/2018] [Indexed: 12/11/2022]
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10
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Yoshida S, Kanno K, Kii I, Misawa Y, Hagiwara M, Hosoya T. Convergent synthesis of trifunctional molecules by three sequential azido-type-selective cycloadditions. Chem Commun (Camb) 2018. [PMID: 29527608 DOI: 10.1039/c8cc01195h] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A facile strategy for the synthesis of trifunctional molecules involving three sequential selective triazole-forming reactions is proposed. This method exploits three kinds of mechanistically different azido-type-selective cycloadditions. Three different azidophiles could be efficiently connected to a triazido platform molecule with three types of azido groups in a consecutive manner, which rendered a practical trifunctional molecule readily available.
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Affiliation(s)
- Suguru Yoshida
- Laboratory of Chemical Bioscience, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University (TMDU), 2-3-10 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062, Japan.
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Heinzmann K, Carter LM, Lewis JS, Aboagye EO. Multiplexed imaging for diagnosis and therapy. Nat Biomed Eng 2017; 1:697-713. [PMID: 31015673 DOI: 10.1038/s41551-017-0131-8] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 08/02/2017] [Indexed: 12/12/2022]
Abstract
Complex molecular and metabolic phenotypes depict cancers as a constellation of different diseases with common themes. Precision imaging of such phenotypes requires flexible and tunable modalities capable of identifying phenotypic fingerprints by using a restricted number of parameters while ensuring sensitivity to dynamic biological regulation. Common phenotypes can be detected by in vivo imaging technologies, and effectively define the emerging standards for disease classification and patient stratification in radiology. However, for the imaging data to accurately represent a complex fingerprint, the individual imaging parameters need to be measured and analysed in relation to their wider spatial and molecular context. In this respect, targeted palettes of molecular imaging probes facilitate the detection of heterogeneity in oncogene-driven alterations and their response to treatment, and lead to the expansion of rational-design elements for the combination of imaging experiments. In this Review, we evaluate criteria for conducting multiplexed imaging, and discuss its opportunities for improving patient diagnosis and the monitoring of therapy.
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Affiliation(s)
- Kathrin Heinzmann
- Department of Surgery and Cancer, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Lukas M Carter
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Jason S Lewis
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Eric O Aboagye
- Department of Surgery and Cancer, Imperial College London, Du Cane Road, London, W12 0NN, UK.
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12
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Chittoor B, Krishnarjuna B, Morales RAV, MacRaild CA, Sadek M, Leung EWW, Robinson SD, Pennington MW, Norton RS. The Single Disulfide-Directed β-Hairpin Fold. Dynamics, Stability, and Engineering. Biochemistry 2017; 56:2455-2466. [PMID: 28437072 DOI: 10.1021/acs.biochem.7b00120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Grafting bioactive peptide sequences onto small cysteine-rich scaffolds is a promising strategy for enhancing their stability and value as novel peptide-based therapeutics. However, correctly folded disulfide-rich peptides can be challenging to produce by either recombinant or synthetic means. The single disulfide-directed β-hairpin (SDH) fold, first observed in contryphan-Vc1, provides a potential alternative to complex disulfide-rich scaffolds. We have undertaken recombinant production of full-length contryphan-Vc1 (rCon-Vc1[Z1Q]) and a truncated analogue (rCon-Vc11-22[Z1Q]), analyzed the backbone dynamics of rCon-Vc1[Z1Q], and probed the conformational and proteolytic stability of these peptides to evaluate the potential of contryphan-Vc1 as a molecular scaffold. Backbone 15N relaxation measurements for rCon-Vc1[Z1Q] indicate that the N-terminal domain of the peptide is ordered up to Thr19, whereas the remainder of the C-terminal region is highly flexible. The solution structure of truncated rCon-Vc11-22[Z1Q] was similar to that of the full-length peptide, indicating that the flexible C-terminus does not have any effect on the structured domain of the peptide. Contryphan-Vc1 exhibited excellent proteolytic stability against trypsin and chymotrypsin but was susceptible to pepsin digestion. We have investigated whether contryphan-Vc1 can accept a bioactive epitope while maintaining the structure of the peptide by introducing peptide sequences based on the DINNN motif of inducible nitric oxide synthase. We show that sCon-Vc11-22[NNN12-14] binds to the iNOS-binding protein SPSB2 with an affinity of 1.3 μM while maintaining the SDH fold. This study serves as a starting point in utilizing the SDH fold as a peptide scaffold.
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Affiliation(s)
- Balasubramanyam Chittoor
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia
| | - Bankala Krishnarjuna
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia
| | - Rodrigo A V Morales
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia
| | - Christopher A MacRaild
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia
| | - Maiada Sadek
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia
| | - Eleanor W W Leung
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia
| | - Samuel D Robinson
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia
| | | | - Raymond S Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia
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Martelli C, Dico AL, Diceglie C, Lucignani G, Ottobrini L. Optical imaging probes in oncology. Oncotarget 2016; 7:48753-48787. [PMID: 27145373 PMCID: PMC5217050 DOI: 10.18632/oncotarget.9066] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 04/10/2016] [Indexed: 01/19/2023] Open
Abstract
Cancer is a complex disease, characterized by alteration of different physiological molecular processes and cellular features. Keeping this in mind, the possibility of early identification and detection of specific tumor biomarkers by non-invasive approaches could improve early diagnosis and patient management.Different molecular imaging procedures provide powerful tools for detection and non-invasive characterization of oncological lesions. Clinical studies are mainly based on the use of computed tomography, nuclear-based imaging techniques and magnetic resonance imaging. Preclinical imaging in small animal models entails the use of dedicated instruments, and beyond the already cited imaging techniques, it includes also optical imaging studies. Optical imaging strategies are based on the use of luminescent or fluorescent reporter genes or injectable fluorescent or luminescent probes that provide the possibility to study tumor features even by means of fluorescence and luminescence imaging. Currently, most of these probes are used only in animal models, but the possibility of applying some of them also in the clinics is under evaluation.The importance of tumor imaging, the ease of use of optical imaging instruments, the commercial availability of a wide range of probes as well as the continuous description of newly developed probes, demonstrate the significance of these applications. The aim of this review is providing a complete description of the possible optical imaging procedures available for the non-invasive assessment of tumor features in oncological murine models. In particular, the characteristics of both commercially available and newly developed probes will be outlined and discussed.
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Affiliation(s)
- Cristina Martelli
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
- Centre of Molecular and Cellular Imaging-IMAGO, Milan, Italy
| | - Alessia Lo Dico
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
- Umberto Veronesi Foundation, Milan, Italy
| | - Cecilia Diceglie
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
- Centre of Molecular and Cellular Imaging-IMAGO, Milan, Italy
- Tecnomed Foundation, University of Milan-Bicocca, Monza, Italy
| | - Giovanni Lucignani
- Centre of Molecular and Cellular Imaging-IMAGO, Milan, Italy
- Department of Health Sciences, University of Milan, Milan, Italy
| | - Luisa Ottobrini
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
- Centre of Molecular and Cellular Imaging-IMAGO, Milan, Italy
- Institute for Molecular Bioimaging and Physiology (IBFM), National Research Council (CNR), Milan, Italy
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Cox N, Kintzing JR, Smith M, Grant GA, Cochran JR. Integrin-Targeting Knottin Peptide-Drug Conjugates Are Potent Inhibitors of Tumor Cell Proliferation. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201603488] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Nick Cox
- Stanford ChEM-H Medicinal Chemistry Knowledge Center; Stanford University; Stanford CA 94305 USA
| | - James R. Kintzing
- Department of Bioengineering; Stanford University; Stanford CA 94305 USA
| | - Mark Smith
- Stanford ChEM-H Medicinal Chemistry Knowledge Center; Stanford University; Stanford CA 94305 USA
| | - Gerald A. Grant
- Department of Neurosurgery; Stanford University; Stanford CA 94305 USA
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15
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Cox N, Kintzing JR, Smith M, Grant GA, Cochran JR. Integrin-Targeting Knottin Peptide-Drug Conjugates Are Potent Inhibitors of Tumor Cell Proliferation. Angew Chem Int Ed Engl 2016; 55:9894-7. [PMID: 27304709 DOI: 10.1002/anie.201603488] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Revised: 05/16/2016] [Indexed: 01/05/2023]
Abstract
Antibody-drug conjugates (ADCs) offer increased efficacy and reduced toxicity compared to systemic chemotherapy. Less attention has been paid to peptide-drug delivery, which has the potential for increased tumor penetration and facile synthesis. We report a knottin peptide-drug conjugate (KDC) and demonstrate that it can selectively deliver gemcitabine to malignant cells expressing tumor-associated integrins. This KDC binds to tumor cells with low-nanomolar affinity, is internalized by an integrin-mediated process, releases its payload intracellularly, and is a highly potent inhibitor of brain, breast, ovarian, and pancreatic cancer cell lines. Notably, these features enable this KDC to bypass a gemcitabine-resistance mechanism found in pancreatic cancer cells. This work expands the therapeutic relevance of knottin peptides to include targeted drug delivery, and further motivates efforts to expand the drug-conjugate toolkit to include non-antibody protein scaffolds.
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Affiliation(s)
- Nick Cox
- Stanford ChEM-H Medicinal Chemistry Knowledge Center, Stanford University, Stanford, CA, 94305, USA
| | - James R Kintzing
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Mark Smith
- Stanford ChEM-H Medicinal Chemistry Knowledge Center, Stanford University, Stanford, CA, 94305, USA
| | - Gerald A Grant
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA
| | - Jennifer R Cochran
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA.
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Zhang C, Kimura R, Abou-Elkacem L, Levi J, Xu L, Gambhir SS. A Cystine Knot Peptide Targeting Integrin αvβ6 for Photoacoustic and Fluorescence Imaging of Tumors in Living Subjects. J Nucl Med 2016; 57:1629-1634. [PMID: 27230926 DOI: 10.2967/jnumed.115.169383] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 04/14/2016] [Indexed: 11/16/2022] Open
Abstract
Photoacoustic imaging is a nonionizing biomedical imaging modality with higher resolution and imaging depth than fluorescence imaging, which has greater sensitivity. The combination of the 2 imaging modalities could improve the detection of cancer. Integrin αvβ6 is a cell surface marker overexpressed in many different cancers. Here, we report the development and evaluation of a dye-labeled cystine knot peptide, which selectively recognizes integrin αvβ6 with high affinity, for photoacoustic and fluorescence imaging. The new dual-modality probe may find clinical application in cancer diagnosis and intraoperative imaging of integrin αvβ6-positive tumors. METHODS An engineered cystine knot peptide, R01, that recognizes integrin αvβ6 was labeled with Atto 740 (A740) and evaluated for its specific cell uptake and its sensitivity threshold. A740-R01 was injected via the tail vein into nude mice xenografted with A431 (integrin αvβ6-positive) or 293T (integrin αvβ6-negative) tumors. Photoacoustic and fluorescence scans of tumors were acquired before and at 0.5, 1, 2, and 4 h after injection of A740-R01. Dynamic photoacoustic scans of various normal organs were also acquired. Ex vivo fluorescence imaging of tissues was performed 1 h after injection. RESULTS The A740-R01 demonstrated integrin αvβ6-dependent binding to A431 cells in culture. Sensitivity studies indicated that the probe may potentially detect lesions as small as 1 or 6 mm3 by fluorescence or photoacoustic imaging, respectively. The photoacoustic and fluorescence signals of A431 xenografts at 1 h after injection were 1.87 ± 0.25 arbitrary units (AU) and 8.27 ± 0.87 AU, respectively. Target specificity was confirmed by low tumor uptake in 293T tumors at 1 h after injection (1.07 ± 0.15 AU and 1.10 ± 0.14 AU for photoacoustic and fluorescence signals, respectively). A740-R01 exhibited hepatobiliary clearance marked by high uptake in the liver, spleen, and intestine but low uptake in the kidneys. CONCLUSION A740-R01 specifically targeted integrin αvβ6 with low nanomolar affinity. A740-R01 was able to detect integrin αvβ6 both in vitro and in vivo by photoacoustic and fluorescence imaging. A740-R01 is able to detect αvβ6-positive tumors in living subjects and may have clinical application in cancer diagnosis and real-time image-guided surgery.
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Affiliation(s)
- Chao Zhang
- Department of Radiology, Molecular Imaging Program at Stanford, Canary Center for Cancer Early Detection, Stanford University, Stanford, California; and Department of Medical Ultrasound, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Richard Kimura
- Department of Radiology, Molecular Imaging Program at Stanford, Canary Center for Cancer Early Detection, Stanford University, Stanford, California; and
| | - Lotfi Abou-Elkacem
- Department of Radiology, Molecular Imaging Program at Stanford, Canary Center for Cancer Early Detection, Stanford University, Stanford, California; and
| | - Jelena Levi
- Department of Radiology, Molecular Imaging Program at Stanford, Canary Center for Cancer Early Detection, Stanford University, Stanford, California; and
| | - Lingyun Xu
- Department of Radiology, Molecular Imaging Program at Stanford, Canary Center for Cancer Early Detection, Stanford University, Stanford, California; and
| | - Sanjiv Sam Gambhir
- Department of Radiology, Molecular Imaging Program at Stanford, Canary Center for Cancer Early Detection, Stanford University, Stanford, California; and
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17
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Protein/peptide-based entry/fusion inhibitors as anti-HIV therapies: challenges and future direction. Rev Med Virol 2015; 26:4-20. [DOI: 10.1002/rmv.1853] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 07/02/2015] [Accepted: 07/15/2015] [Indexed: 11/07/2022]
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18
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Paulus A, Desai P, Carney B, Carlucci G, Reiner T, Brand C, Weber WA. Development of a clickable bimodal fluorescent/PET probe for in vivo imaging. EJNMMI Res 2015; 5:120. [PMID: 26285667 PMCID: PMC4540712 DOI: 10.1186/s13550-015-0120-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 07/27/2015] [Indexed: 01/13/2023] Open
Abstract
Background Fluorescent imaging agents are becoming evermore important in preclinical and clinical research. They do, however, suffer from poor tissue penetration, which makes optical fluorescence imaging incompatible with whole-body imaging techniques. The design of novel bimodal PET active and fluorescent tracers could therefore combine the benefits of optical imaging with radioactively labeled imaging probes. Herein, we report the synthesis and evaluation of a clickable 18F-labeled fluorescent dye. Methods An azide-modified BODIPY-Fl dye could be successfully radio-labeled with 18F using an 18F/19F exchange reaction of the boron-fluoride core of the BODIPY dye to yield a clickable bimodal PET/fluorescent imaging tool. In vitro as well as in vivo imaging (PET/fluorescence) using a bombesin analog was conducted to study the applicability of the dual-modality imaging probe. Results We use the radio-labeled small molecule, 18F-BODIPY-azide to label site-specifically different targeted peptides, based on a standard modular labeling protocol. Following the synthesis of a bimodal bombesin analog, we determine the peptide tracer’s performance in vitro and in vivo, exploring both the optical as well as PET imaging capabilities. Conclusion This versatile methodology has the potential to have a transformational impact on 18F radiotracer synthesis, opening the door for rapid screening of novel-labeled peptide tracers, both on the cellular (optical) as well as whole-body (PET) level. Electronic supplementary material The online version of this article (doi:10.1186/s13550-015-0120-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Andreas Paulus
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, 10065, New York, NY, USA,
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Sun Y, Ma X, Cheng K, Wu B, Duan J, Chen H, Bu L, Zhang R, Hu X, Deng Z, Xing L, Hong X, Cheng Z. Strained Cyclooctyne as a Molecular Platform for Construction of Multimodal Imaging Probes. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201500941] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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20
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Sun Y, Ma X, Cheng K, Wu B, Duan J, Chen H, Bu L, Zhang R, Hu X, Deng Z, Xing L, Hong X, Cheng Z. Strained cyclooctyne as a molecular platform for construction of multimodal imaging probes. Angew Chem Int Ed Engl 2015; 54:5981-4. [PMID: 25800807 DOI: 10.1002/anie.201500941] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Indexed: 11/06/2022]
Abstract
Small-molecule-based multimodal and multifunctional imaging probes play prominent roles in biomedical research and have high clinical translation ability. A novel multimodal imaging platform using base-catalyzed double addition of thiols to a strained internal alkyne such as bicyclo[6.1.0]nonyne has been established in this study, thus allowing highly selective assembly of various functional units in a protecting-group-free manner. Using this molecular platform, novel dual-modality (PET and NIRF) uPAR-targeted imaging probe: (64)Cu-CHS1 was prepared and evaluated in U87MG cells and tumor-bearing mice models. The excellent PET/NIRF imaging characteristics such as good tumor uptake (3.69%ID/g at 2 h post-injection), high tumor contrast, and specificity were achieved in the small-animal models. These attractive imaging properties make (64)Cu-CHS1 a promising probe for clinical use.
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Affiliation(s)
- Yao Sun
- State Key Laboratory of Virology, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan 430071 (China); Molecular Imaging Program at Stanford (MIPS), Bio-X Program, and Department of Radiology, Stanford University, California, 94305-5344 (USA)
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Stephan H, Walther M, Fähnemann S, Ceroni P, Molloy JK, Bergamini G, Heisig F, Müller CE, Kraus W, Comba P. Bispidines for Dual Imaging. Chemistry 2014; 20:17011-8. [DOI: 10.1002/chem.201404086] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Indexed: 11/08/2022]
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Abstract
Molecular imaging non-invasively visualizes and characterizes the biologic functions and mechanisms in living organisms at a molecular level. In recent years, advances in imaging instruments, imaging probes, assay methods, and quantification techniques have enabled more refined and reliable images for more accurate diagnoses. Multimodal imaging combines two or more imaging modalities into one system to produce details in clinical diagnostic imaging that are more precise than conventional imaging. Multimodal imaging offers complementary advantages: high spatial resolution, soft tissue contrast, and biological information on the molecular level with high sensitivity. However, combining all modalities into a single imaging probe involves problems yet to be solved due to the requirement of high dose contrast agents for a component of imaging modality with low sensitivity. The introduction of targeting moieties into the probes enhances the specific binding of targeted multimodal imaging modalities and selective accumulation of the imaging agents at a disease site to provide more accurate diagnoses. An extensive list of prior reports on the targeted multimodal imaging probes categorized by each modality is presented and discussed. In addition to accurate diagnosis, targeted multimodal imaging agents carrying therapeutic medications make it possible to visualize the theranostic effect and the progress of disease. This will facilitate the development of an imaging-guided therapy, which will widen the application of the targeted multimodal imaging field to experiments in vivo.
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23
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Liu Z, Radtke MA, Wong MQ, Lin KS, Yapp DT, Perrin DM. Dual Mode Fluorescent 18F-PET Tracers: Efficient Modular Synthesis of Rhodamine-[cRGD]2-[18F]-Organotrifluoroborate, Rapid, and High Yielding One-Step 18F-Labeling at High Specific Activity, and Correlated in Vivo PET Imaging and ex Vivo Fluorescence. Bioconjug Chem 2014; 25:1951-62. [DOI: 10.1021/bc5003357] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zhibo Liu
- Chemistry
Department University of British Columbia 2036 Main Mall, Vancouver, British Columbia V6T-1Z1, Canada
| | - Mark Alex Radtke
- Chemistry
Department University of British Columbia 2036 Main Mall, Vancouver, British Columbia V6T-1Z1, Canada
| | | | | | | | - David M. Perrin
- Chemistry
Department University of British Columbia 2036 Main Mall, Vancouver, British Columbia V6T-1Z1, Canada
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Bimodal imaging probes for combined PET and OI: recent developments and future directions for hybrid agent development. BIOMED RESEARCH INTERNATIONAL 2014; 2014:153741. [PMID: 24822177 PMCID: PMC4009187 DOI: 10.1155/2014/153741] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 03/18/2014] [Indexed: 12/02/2022]
Abstract
Molecular imaging—and especially positron emission tomography (PET)—has gained increasing importance for diagnosis of various diseases and thus experiences an increasing dissemination. Therefore, there is also a growing demand for highly affine PET tracers specifically accumulating and visualizing target structures in the human body. Beyond the development of agents suitable for PET alone, recent tendencies aim at the synthesis of bimodal imaging probes applicable in PET as well as optical imaging (OI), as this combination of modalities can provide clinical advantages. PET, due to the high tissue penetration of the γ-radiation emitted by PET nuclides, allows a quantitative imaging able to identify and visualize tumors and metastases in the whole body. OI on the contrary visualizes photons exhibiting only a limited tissue penetration but enables the identification of tumor margins and infected lymph nodes during surgery without bearing a radiation burden for the surgeon. Thus, there is an emerging interest in bimodal agents for PET and OI in order to exploit the potential of both imaging techniques for the imaging and treatment of tumor diseases. This short review summarizes the available hybrid probes developed for dual PET and OI and discusses future directions for hybrid agent development.
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Zhu X, Li J, Hong Y, Kimura RH, Ma X, Liu H, Qin C, Hu X, Hayes TR, Benny P, Gambhir SS, Cheng Z. 99mTc-labeled cystine knot peptide targeting integrin αvβ6 for tumor SPECT imaging. Mol Pharm 2014; 11:1208-17. [PMID: 24524409 PMCID: PMC3993876 DOI: 10.1021/mp400683q] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Integrin
αvβ6 is overexpressed
in a variety of cancers, and its expression is often associated with
poor prognosis. Therefore, there is a need to develop affinity reagents
for noninvasive imaging of integrin αvβ6 expression since it may provide early cancer diagnosis, more
accurate prognosis, and better treatment planning. We recently engineered
and validated highly stable cystine knot peptides that selectively
bind integrin αvβ6 with no cross-reactivity
to integrins αvβ5, α5β1, or αvβ3, also
known to be overexpressed in many cancers. Here, we developed a single
photon emission computed tomography (SPECT) probe for imaging integrin
αvβ6 positive tumors. Cystine knot
peptide, S02, was first conjugated with a single amino
acid chelate (SAAC) and labeled with [99mTc(H2O)3(CO)3]+. The resulting probe, 99mTc-SAAC-S02, was then evaluated by in
vitro cell uptake studies using two αvβ6 positive cell lines (human lung adenocarcinoma cell line
HCC4006 and pancreatic cancer cell line BxPC-3) and two αvβ6 negative cell lines (human lung adenocarcinoma
cell line H838 and human embryonic kidney cell line 293T). Next, SPECT/CT
and biodistribution studies were performed in nude mice bearing HCC4006
and H838 tumor xenografts to evaluate the in vivo performance of 99mTc-SAAC-S02. Significant
differences in the uptake of 99mTc-SAAC-S02
were observed in αvβ6 positive vs
negative cells (P < 0.05). Biodistribution and
small animal SPECT/CT studies revealed that 99mTc-SAAC-S02 accumulated to moderate levels in antigen positive tumors
(∼2% ID/g at 1 and 6 h postinjection, n =
3 or 4/group). Moreover, the probe demonstrated tumor-to-background
tissue ratios of 6.81 ± 2.32 (tumor-to-muscle) and 1.63 ±
0.18 (tumor-to-blood) at 6 h postinjection in αvβ6 positive tumor xenografts. Co-incubation of the probe with
excess amount of unlabeled S02 as a blocking agent demonstrated
significantly reduced tumor uptake, which is consistent with specific
binding to the target. Renal filtration was the main route of clearance.
In conclusion, knottin peptides are excellent scaffolds for which
to develop highly stable imaging probes for a variety of oncological
targets. 99mTc-SAAC-S02 demonstrates promise
for use as a SPECT agent to image integrin αvβ6 expression in living systems.
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Affiliation(s)
- Xiaohua Zhu
- Molecular Imaging Program at Stanford (MIPS), Department of Radiology, and Bio-X Program, Canary Center at Stanford for Cancer Early Detection, Stanford University , Stanford, California 94305-5344, United States
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Knottins: disulfide-bonded therapeutic and diagnostic peptides. DRUG DISCOVERY TODAY. TECHNOLOGIES 2013; 9:e1-e70. [PMID: 24064239 DOI: 10.1016/j.ddtec.2011.07.003] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Stern LA, Case BA, Hackel BJ. Alternative Non-Antibody Protein Scaffolds for Molecular Imaging of Cancer. Curr Opin Chem Eng 2013; 2. [PMID: 24358455 DOI: 10.1016/j.coche.2013.08.009] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The development of improved methods for early detection and characterization of cancer presents a major clinical challenge. One approach that has shown excellent potential in preclinical and clinical evaluation is molecular imaging with small-scaffold, non-antibody based, engineered proteins. These novel diagnostic agents produce high contrast images due to their fast clearance from the bloodstream and healthy tissues, can be evolved to bind a multitude of cancer biomarkers, and are easily functionalized by site-specific bioconjugation methods. Several small protein scaffolds have been verified for in vivo molecular imaging including affibodies and their two-helix variants, knottins, fibronectins, DARPins, and several natural ligands. Further, the biodistribution of these engineered ligands can be optimized through rational mutation of the conserved regions, careful selection and placement of chelator, and modification of molecular size.
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Affiliation(s)
- Lawrence A Stern
- Department of Chemical Engineering and Materials Science, University of Minnesota - Twin Cities, Minneapolis, MN 55455
| | - Brett A Case
- Department of Chemical Engineering and Materials Science, University of Minnesota - Twin Cities, Minneapolis, MN 55455
| | - Benjamin J Hackel
- Department of Chemical Engineering and Materials Science, University of Minnesota - Twin Cities, Minneapolis, MN 55455
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von Recum HA, Pokorski JK. Peptide and protein-based inhibitors of HIV-1 co-receptors. Exp Biol Med (Maywood) 2013; 238:442-9. [PMID: 23856897 DOI: 10.1177/1535370213480696] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Human immunodeficiency virus (HIV) afflicts an estimated 30 million people globally, making it a continuing pandemic. Despite major research efforts, the rate of new infections has remained relatively static over time. This article reviews an emerging strategy for the treatment of HIV, the inhibition of the co-receptors necessary for HIV entry, CCR5 and CXCR4. The aim of this article is to highlight potential therapeutics derived from peptides and proteins that show particular promise in HIV treatment. Molecules that act on CCR5, CXCR4 or on both receptors will be discussed herein.
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Affiliation(s)
- Horst A von Recum
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
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29
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Moore SJ, Hayden Gephart MG, Bergen JM, Su YS, Rayburn H, Scott MP, Cochran JR. Engineered knottin peptide enables noninvasive optical imaging of intracranial medulloblastoma. Proc Natl Acad Sci U S A 2013; 110:14598-603. [PMID: 23950221 PMCID: PMC3767496 DOI: 10.1073/pnas.1311333110] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Central nervous system tumors carry grave clinical prognoses due to limited effectiveness of surgical resection, radiation, and chemotherapy. Thus, improved strategies for brain tumor visualization and targeted treatment are critically needed. We demonstrate that mouse cerebellar medulloblastoma (MB) can be targeted and illuminated with a fluorescent, engineered cystine knot (knottin) peptide that binds with high affinity to αvβ3, αvβ5, and α5β1 integrin receptors. This integrin-binding knottin peptide, denoted EETI 2.5F, was evaluated as a molecular imaging probe in both orthotopic and genetic models of MB. Following tail vein injection, fluorescence arising from dye-conjugated EETI 2.5F was localized to the tumor compared with the normal surrounding brain tissue, as measured by optical imaging. The imaging signal intensity correlated with tumor volume. Due to its unique ability to bind to α5β1 integrin, EETI 2.5F showed superior in vivo and ex vivo brain tumor imaging contrast compared with other engineered integrin-binding knottin peptides and with c(RGDfK), a well-studied integrin-binding peptidomimetic. Next, EETI 2.5F was fused to an antibody fragment crystallizable (Fc) domain (EETI 2.5F-Fc) to determine if a larger integrin-binding protein could also target intracranial brain tumors. EETI 2.5F-Fc, conjugated to a fluorescent dye, illuminated MB following i.v. injection and was able to distribute throughout the tumor parenchyma. In contrast, brain tumor imaging signals were not detected in mice injected with EETI 2.5F proteins containing a scrambled integrin-binding sequence, demonstrating the importance of target specificity. These results highlight the potential of using EETI 2.5F and EETI 2.5-Fc as targeted molecular probes for brain tumor imaging.
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Affiliation(s)
- Sarah J. Moore
- Departments of Bioengineering
- Center for Children’s Brain Tumors
- Stanford Cancer Institute, and
| | - Melanie G. Hayden Gephart
- Departments of Bioengineering
- Neurosurgery
- Developmental Biology
- Center for Children’s Brain Tumors
- Stanford Cancer Institute, and
| | - Jamie M. Bergen
- Departments of Bioengineering
- Center for Children’s Brain Tumors
- Stanford Cancer Institute, and
| | - YouRong S. Su
- Departments of Bioengineering
- Developmental Biology
- Genetics, and
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305
| | - Helen Rayburn
- Departments of Bioengineering
- Developmental Biology
- Genetics, and
- Center for Children’s Brain Tumors
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305
| | - Matthew P. Scott
- Departments of Bioengineering
- Developmental Biology
- Genetics, and
- Center for Children’s Brain Tumors
- Stanford Cancer Institute, and
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305
| | - Jennifer R. Cochran
- Departments of Bioengineering
- Chemical Engineering
- Center for Children’s Brain Tumors
- Stanford Cancer Institute, and
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Abstract
The suite of currently used drugs can be divided into two categories - traditional 'small molecule' drugs with typical molecular weights of <500 Da but with oral bioavailability, and much larger 'biologics' typically >5000 Da that are not orally bioavailable and need to be delivered via injection. Due to their small size, conventional small molecule drugs may suffer from reduced target selectivity that often ultimately manifests in human side-effects, whereas protein therapeutics tend to be exquisitely specific for their targets due to many more interactions with them, but this comes at a cost of low bioavailability, poor membrane permeability, and metabolic instability. The time has now come to reinvestigate new drug leads that fit between these two molecular weight extremes, with the goal of combining advantages of small molecules (cost, conformational restriction, membrane permeability, metabolic stability, oral bioavailability) with those of proteins (natural components, target specificity, high potency). This article uses selected examples of peptides to highlight the importance of peptide drugs, some potential new opportunities for their exploitation, and some difficult challenges ahead in this field.
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Affiliation(s)
- David J Craik
- Division of Chemistry & Structural Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld 4072, Australia.
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Moore SJ, Leung CL, Norton HK, Cochran JR. Engineering agatoxin, a cystine-knot peptide from spider venom, as a molecular probe for in vivo tumor imaging. PLoS One 2013; 8:e60498. [PMID: 23573262 PMCID: PMC3616073 DOI: 10.1371/journal.pone.0060498] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 02/26/2013] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Cystine-knot miniproteins, also known as knottins, have shown great potential as molecular scaffolds for the development of targeted therapeutics and diagnostic agents. For this purpose, previous protein engineering efforts have focused on knottins based on the Ecballium elaterium trypsin inhibitor (EETI) from squash seeds, the Agouti-related protein (AgRP) neuropeptide from mammals, or the Kalata B1 uterotonic peptide from plants. Here, we demonstrate that Agatoxin (AgTx), an ion channel inhibitor found in spider venom, can be used as a molecular scaffold to engineer knottins that bind with high-affinity to a tumor-associated integrin receptor. METHODOLOGY/PRINCIPAL FINDINGS We used a rational loop-grafting approach to engineer AgTx variants that bound to αvβ3 integrin with affinities in the low nM range. We showed that a disulfide-constrained loop from AgRP, a structurally-related knottin, can be substituted into AgTx to confer its high affinity binding properties. In parallel, we identified amino acid mutations required for efficient in vitro folding of engineered integrin-binding AgTx variants. Molecular imaging was used to evaluate in vivo tumor targeting and biodistribution of an engineered AgTx knottin compared to integrin-binding knottins based on AgRP and EETI. Knottin peptides were chemically synthesized and conjugated to a near-infrared fluorescent dye. Integrin-binding AgTx, AgRP, and EETI knottins all generated high tumor imaging contrast in U87MG glioblastoma xenograft models. Interestingly, EETI-based knottins generated significantly lower non-specific kidney imaging signals compared to AgTx and AgRP-based knottins. CONCLUSIONS/SIGNIFICANCE In this study, we demonstrate that AgTx, a knottin from spider venom, can be engineered to bind with high affinity to a tumor-associated receptor target. This work validates AgTx as a viable molecular scaffold for protein engineering, and further demonstrates the promise of using tumor-targeting knottins as probes for in vivo molecular imaging.
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Affiliation(s)
- Sarah J. Moore
- Department of Bioengineering, Stanford University, Stanford, California, United States of America
| | - Cheuk Lun Leung
- Department of Chemical Engineering, Stanford University, Stanford, California, United States of America
| | - Heidi K. Norton
- Department of Bioengineering, Stanford University, Stanford, California, United States of America
| | - Jennifer R. Cochran
- Department of Bioengineering, Stanford University, Stanford, California, United States of America
- Department of Chemical Engineering, Stanford University, Stanford, California, United States of America
- Stanford Cancer Institute and Bio-X Program, Stanford, California, United States of America
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Zatsikha YV, Yakubovskyi VP, Shandura MP, Kovtun YP. Boradipyrromethenecyanines on the base of a BODIPY nucleus annelated with a pyridone ring: a new approach to long-wavelength dual fluorescent probe design. RSC Adv 2013. [DOI: 10.1039/c3ra42633e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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A novel radiofluorinated agouti-related protein for tumor angiogenesis imaging. Amino Acids 2012; 44:673-81. [PMID: 22945905 DOI: 10.1007/s00726-012-1391-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2012] [Accepted: 08/20/2012] [Indexed: 10/27/2022]
Abstract
A novel protein scaffold based on the cystine knot domain of the agouti-related protein (AgRP) has been used to engineer mutants that can bind to the α(v)β(3) integrin receptor with high affinity and specificity. In the current study, an (18)F-labeled AgRP mutant (7C) was prepared and evaluated as a positron emission tomography (PET) probe for imaging tumor angiogenesis. AgRP-7C was synthesized by solid phase peptide synthesis and site-specifically conjugated with 4-nitrophenyl 2-(18/19)F-fluoropropionate ((18/19)F-NFP) to produce the fluorinated peptide, (18/19)F-FP-AgRP-7C. Competition binding assays were used to measure the relative affinities of AgRP-7C and (19)F-FP-AgRP-7C to human glioblastoma U87MG cells that overexpress α(v)β(3) integrin. In addition, biodistribution, metabolic stability, and small animal PET imaging studies were conducted with (18)F-FP-AgRP-7C using U87MG tumor-bearing mice. Both AgRP-7C and (19)F-FP-AgRP-7C specifically competed with (125)I-echistatin for binding to U87MG cells with half maximal inhibitory concentration (IC(50)) values of 9.40 and 8.37 nM, respectively. Non-invasive small animal PET imaging revealed that (18)F-FP-AgRP-7C exhibited rapid and good tumor uptake (3.24 percentage injected dose per gram [% ID/g] at 0.5 h post injection [p.i.]). The probe was rapidly cleared from the blood and from most organs, resulting in excellent tumor-to-normal tissue contrasts. Tumor uptake and rapid clearance were further confirmed with biodistribution studies. Furthermore, co-injection of (18)F-FP-AgRP-7C with a large molar excess of blocking peptide c(RGDyK) significantly inhibited tumor uptake in U87MG xenograft models, demonstrating the integrin-targeting specificity of the probe. Metabolite assays showed that the probe had high stability, making it suitable for in vivo applications. (18)F-FP-AgRP-7C exhibits promising in vivo properties such as rapid tumor targeting, good tumor uptake, and excellent tumor-to-normal tissue ratios, and warrants further investigation as a novel PET probe for imaging tumor angiogenesis.
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Bernhard C, Moreau M, Lhenry D, Goze C, Boschetti F, Rousselin Y, Brunotte F, Denat F. DOTAGA-anhydride: a valuable building block for the preparation of DOTA-like chelating agents. Chemistry 2012; 18:7834-41. [PMID: 22615050 DOI: 10.1002/chem.201200132] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Indexed: 11/07/2022]
Abstract
A DOTA derivative that contains an anhydride group was readily synthesized by reacting DOTAGA with acetic anhydride and its reactivity was investigated. Opening the anhydride with propylamine led to the selective formation of one of two possible regioisomers. The structure of the obtained isomer was unambiguously determined by 1D and 2D NMR experiments, including COSY, HMBC, and NOESY techniques. This bifunctional chelating agent offers a convenient and attractive approach for labeling biomolecules and, more generally, for the synthesis of a large range of DOTA derivatives. The scope of the reaction was extended to prepare DOTA-like compounds that contained various functional groups, such as isothiocyanate, thiol, ester, and amino acid moieties. This versatile building block was also used for the synthesis of a bimodal tag for SPECT or PET/optical imaging.
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Affiliation(s)
- Claire Bernhard
- Institut de Chimie Moléculaire de l'Université de Bourgogne, UMR CNRS 6302, 9 avenue Alain Savary, 21000 Dijon, France
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Abstract
Peptide-based toxins have attracted much attention in recent years for their exciting potential applications in drug design and development. This interest has arisen because toxins are highly potent and selectively target a range of physiologically important receptors. However, peptides suffer from a number of disadvantages, including poor in vivo stability and poor bioavailability. A number of naturally occurring cyclic peptides have been discovered in plants, animals, and bacteria that have exceptional stability and potentially ameliorate these disadvantages. The lessons learned from studies of the structures, stabilities, and biological activities of these cyclic peptides can be applied to the reengineering of toxins that are not naturally cyclic but are amenable to cyclization. In this chapter, we describe solid-phase chemical synthetic methods for the reengineering of peptide toxins to improve their suitability as therapeutic, diagnostic, or imaging agents. The focus is on small disulfide-rich peptides from the venoms of cone snails and scorpions, but the technology is potentially widely applicable to a number of other peptide-based toxins.
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Affiliation(s)
- Richard J Clark
- School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
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Abstract
Cystine-knot miniproteins, also known as knottins, contain a conserved core of three tightly woven disulfide bonds which impart extraordinary thermal and proteolytic stability. Interspersed between their conserved cysteine residues are constrained loops that possess high levels of sequence diversity among knottin family members. Together these attributes make knottins promising molecular scaffolds for protein engineering and translational applications. While naturally occurring knottins have shown potential as both diagnostic agents and therapeutics, protein engineering is playing an important and increasing role in creating designer molecules that bind to a myriad of biomedical targets. Toward this goal, rational and combinatorial approaches have been used to engineer knottins with novel molecular recognition properties. Here, methods are described for creating and screening knottin libraries using yeast surface display and fluorescence-activated cell sorting. Protocols are also provided for producing knottins by synthetic and recombinant methods, and for measuring the binding affinity of knottins to target proteins expressed on the cell surface.
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Affiliation(s)
- Sarah J Moore
- Department of Bioengineering, Cancer Institute, and Bio-X Program, Stanford University, Stanford, California, USA
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Miao Z, Levi J, Cheng Z. Protein scaffold-based molecular probes for cancer molecular imaging. Amino Acids 2011; 41:1037-47. [PMID: 20174842 PMCID: PMC2914822 DOI: 10.1007/s00726-010-0503-9] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Accepted: 01/25/2010] [Indexed: 01/18/2023]
Abstract
Protein scaffold molecules are powerful reagents for targeting various cell signal receptors, enzymes, cytokines and other cancer-related molecules. They belong to the peptide and small protein platform with distinct properties. For the purpose of development of new generation molecular probes, various protein scaffold molecules have been labeled with imaging moieties and evaluated both in vitro and in vivo. Among the evaluated probes Affibody molecules and analogs, cystine knot peptides, and nanobodies have shown especially good characteristics as protein scaffold platforms for development of in vivo molecular probes. Quantitative data obtained from positron emission tomography, single photon emission computed tomography/CT, and optical imaging together with biodistribution studies have shown high tumor uptakes and high tumor-to-blood ratios for these probes. High tumor contrast imaging has been obtained within 1 h after injection. The success of those molecular probes demonstrates the adequacy of protein scaffold strategy as a general approach in molecular probe development.
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Affiliation(s)
- Zheng Miao
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, CA 94305-5344, USA
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Mansi L, Virgolini I. Diagnosis and therapy are walking together on radiopeptides' avenue. Eur J Nucl Med Mol Imaging 2011; 38:605-12. [PMID: 21365250 DOI: 10.1007/s00259-011-1762-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Azhdarinia A, Wilganowski N, Robinson H, Ghosh P, Kwon S, Lazard ZW, Davis AR, Olmsted-Davis E, Sevick-Muraca EM. Characterization of chemical, radiochemical and optical properties of a dual-labeled MMP-9 targeting peptide. Bioorg Med Chem 2011; 19:3769-76. [PMID: 21612930 DOI: 10.1016/j.bmc.2011.04.054] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 04/25/2011] [Accepted: 04/30/2011] [Indexed: 10/18/2022]
Abstract
Optical imaging possesses similar sensitivity to nuclear imaging and has led to the emergence of multimodal approaches with dual-labeled nuclear/near-infrared (NIR) agents. The growing impact of (68)Ga (t(1/2)=68 min) labeled peptides on preclinical and clinical research offers a promising opportunity to merge the high spatial resolution of NIR imaging with the clinically-accepted positron emission tomography (PET). Previously, dual-labeled agents have been prepared with longer-lived radiometals and showed no detrimental effects on optical properties as a result of radiolabeling. In this study, we selected a peptide (M(2)) that targets MMP-2/9 and is dual-labeled with IRDye 800 CW and (68)Ga. Since (68)Ga chelation typically requires low pH (3.5-4) and elevated heating temperatures (95 °C), we sought to evaluate the impact of (68)Ga labeling on the optical properties of M(2). An efficient method for preparation of (68)Ga-M(2) was developed and reaction conditions were optimized. Stability studies in PBS, DTPA, and serum were performed and high levels of intact agent were evident under each condition. The addition of multiple reporters to a targeting agent adds further complexity to the characterization and validation and thus requires not only testing to ensure the agent is stable chemically and radiochemically, but also optically. Therefore, fluorescence properties were evaluated using a spectrofluorometer as well as by fluorescence detection via HPLC. It was determined that (68)Ga-labeling conditions did not impair the fluorescent properties of the agent. The agent was then used for in vivo imaging in a mouse model of heterotopic ossification (HO) with activated MMP-9 expression as an early biomarker which precedes mineralization. Although (68)Ga-complexation greatly reduced binding affinity of the peptide and negated tracer uptake on PET, NIR imaging showed consistent fluorescent signal that correlated to MMP-9 expression. This attests to the feasibility of using (68)Ga/NIR for dual-labeling of other peptides or small molecules for multimodality molecular imaging.
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Affiliation(s)
- Ali Azhdarinia
- Center for Molecular Imaging, The Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center, Houston, TX 77030, USA.
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Abstract
Targeted radionuclide therapy, which is based on the selective delivery of a sufficient radiation dose to tumors without significantly affecting normal tissues, is a promising therapeutic approach for the treatment of a wide variety of malignancies. Integrins, a family of cell adhesion molecules, play key roles during tumor angiogenesis and metastasis. Among all the integrins, αvβ3 seems to be the most important in the process of tumor angiogenesis. Integrin αvβ3 is highly expressed on activated endothelial cells, new-born vessels as well as some tumor cells, but is not present in resting endothelial cells and most normal organ systems, making it a suitable target for anti-tumor therapy. In this review, we summarize the current development and applications of antibody-, peptide-, and other ligand-based integrin targeted radiotherapeutics for tumor radiation therapy.
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Abstract
The cystine knot is a structural motif that confers exceptional stability on proteins. Here we provide an update on the topology of the cystine knot and the combinatorial diversity of proteins that contain it. We describe recent chemical biology studies that have utilised this structural motif for the development of potential therapeutic or diagnostic agents. The cystine knot appears to have evolved in fungi, plants and animals as a stable and adaptable framework for the display of a wide variety of bioactive peptide sequences, but is amenable to chemical or recombinant synthesis and thus has a wide range of applications in chemistry, biology and medicine.
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Kimura RH, Jones DS, Jiang L, Miao Z, Cheng Z, Cochran JR. Functional mutation of multiple solvent-exposed loops in the Ecballium elaterium trypsin inhibitor-II cystine knot miniprotein. PLoS One 2011; 6:e16112. [PMID: 21364742 PMCID: PMC3041754 DOI: 10.1371/journal.pone.0016112] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Accepted: 12/08/2010] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND The Ecballium elaterium trypsin inhibitor (EETI-II), a 28-amino acid member of the knottin family of peptides, contains three interwoven disulfide bonds that form multiple solvent-exposed loops. Previously, the trypsin binding loop of EETI-II has been engineered to confer binding to several alternative molecular targets. Here, EETI-II was further explored as a molecular scaffold for polypeptide engineering by evaluating the ability to mutate two of its structurally adjacent loops. METHODOLOGY/PRINCIPAL FINDINGS Yeast surface display was used to engineer an EETI-II mutant containing two separate integrin binding epitopes. The resulting knottin peptide was comprised of 38 amino acids, and contained 11- and 10-residue loops compared to wild-type EETI-II, which naturally contains 6- and 5-residue loops, respectively. This knottin peptide bound to α(v)β(3) and α(v)β(5) integrins with affinities in the low nanomolar range, but bound weakly to the related integrins α(5)β(1) and α(iib)β(3). In addition, the engineered knottin peptide inhibited tumor cell adhesion to vitronectin, an extracellular matrix protein that binds to α(v)β(3) and α(v)β(5) integrins. A (64)Cu radiolabeled version of this knottin peptide demonstrated moderate serum stability and excellent tumor-to-muscle and tumor-to-blood ratios by positron emission tomography imaging in human tumor xenograft models. Tumor uptake was ∼3-5% injected dose per gram (%ID/g) at one hour post injection, with rapid clearance of probe through the kidneys. CONCLUSIONS/SIGNIFICANCE We demonstrated that multiple loops of EETI-II can be mutated to bind with high affinity to tumor-associated integrin receptors. The resulting knottin peptide contained 21 (>50%) non-native amino acids within two mutated loops, indicating that extended loop lengths and sequence diversity were well tolerated within the EETI-II scaffold. A radiolabeled version of this knottin peptide showed promise for non-invasive imaging of integrin expression in living subjects. However, reduced serum and metabolic stability were observed compared to an engineered integrin-binding EETI-II knottin peptide containing only one mutated loop.
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Affiliation(s)
- Richard H. Kimura
- Department of Radiology, Molecular Imaging Program at Stanford (MIPS), Cancer Center, Bio-X Program, Stanford University, Stanford, California, United States of America
| | - Douglas S. Jones
- Department of Bioengineering, Cancer Center, Bio-X Program, Stanford University, Stanford, California, United States of America
| | - Lei Jiang
- Department of Radiology, Molecular Imaging Program at Stanford (MIPS), Cancer Center, Bio-X Program, Stanford University, Stanford, California, United States of America
| | - Zheng Miao
- Department of Radiology, Molecular Imaging Program at Stanford (MIPS), Cancer Center, Bio-X Program, Stanford University, Stanford, California, United States of America
| | - Zhen Cheng
- Department of Radiology, Molecular Imaging Program at Stanford (MIPS), Cancer Center, Bio-X Program, Stanford University, Stanford, California, United States of America
| | - Jennifer R. Cochran
- Department of Bioengineering, Cancer Center, Bio-X Program, Stanford University, Stanford, California, United States of America
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Current molecular imaging positron emitting radiotracers in oncology. Nucl Med Mol Imaging 2011; 45:1-14. [PMID: 24899972 DOI: 10.1007/s13139-011-0075-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Accepted: 01/21/2011] [Indexed: 12/21/2022] Open
Abstract
Molecular imaging is one of the fastest growing areas of medical imaging. Positron emission tomography (PET) has been widely used in the clinical management of patients with cancer. Nuclear imaging provides biological information at the cellular, subcellular, and molecular level in living subjects with non-invasive procedures. In particular, PET imaging takes advantage of traditional diagnostic imaging techniques and introduces positron-emitting probes to determine the expression of indicative molecular targets at different stages of cancer. (18)F-fluorodeoxyglucose ((18)F-FDG), the only FDA approved oncological PET tracer, has been widely utilized in cancer diagnosis, staging, restaging, and even monitoring response to therapy; however, (18)F-FDG is not a tumor-specific PET tracer. Over the last decade, many promising tumor-specific PET tracers have been developed and evaluated in preclinical and clinical studies. This review provides an overview of the current non-(18)F-FDG PET tracers in oncology that have been developed based on tumor characteristics such as increased metabolism, hyperproliferation, angiogenesis, hypoxia, apoptosis, and tumor-specific antigens and surface receptors.
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Ting R, Aguilera TA, Crisp JL, Hall DJ, Eckelman WC, Vera DR, Tsien RY. Fast 18F labeling of a near-infrared fluorophore enables positron emission tomography and optical imaging of sentinel lymph nodes. Bioconjug Chem 2011; 21:1811-9. [PMID: 20873712 PMCID: PMC2957852 DOI: 10.1021/bc1001328] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We combine a novel boronate trap for F− with a near-infrared fluorophore into a single molecule. Attachment to targeting ligands enables localization by positron emission tomography (PET) and near-infrared fluorescence (NIRF). Our first application of this generic tag is to label Lymphoseek (tilmanocept), an agent designed for receptor-specific sentinel lymph node (SLN) mapping. The new conjugate incorporates 18F− in a single, aqueous step, targets mouse SLN rapidly (1 h) with reduced distal lymph node accumulation, permits PET or scintigraphic imaging of SLN, and enables NIRF-guided excision and histological verification even after 18F decay. This embodiment is superior to current SLN mapping agents such as nontargeted [99mTc]sulfur colloids and Isosulfan Blue, as well as the phase III targeted ligand [99mTc]SPECT Lymphoseek counterpart, species that are visible by SPECT or visible absorbance separately. Facile incorporation of 18F into a NIRF probe should promote many synergistic PET and NIRF combinations.
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Affiliation(s)
- Richard Ting
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093, USA
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Kuil J, Velders AH, van Leeuwen FWB. Multimodal tumor-targeting peptides functionalized with both a radio- and a fluorescent label. Bioconjug Chem 2011; 21:1709-19. [PMID: 20812730 DOI: 10.1021/bc100276j] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The use of monolabeled tumor-targeting peptides for molecular imaging is widespread. However, it is often desirable to use the same compound for different clinical applications, e.g., combined pre- and intraoperative tumor detection. On the basis of their detection sensitivity, the combination of radioactivity and fluorescence is probably the most valuable in multimodal molecular imaging. In this review, we compare multimodal peptide derivatives and discuss the influence of the diagnostic labels on receptor affinity and biodistribution. On the basis of the described constructs, we propose improvements for the design of future multimodal tumor-targeting peptide derivatives.
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Affiliation(s)
- Joeri Kuil
- Division of Diagnostic Oncology, The Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands
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Park JC, Yu MK, An GI, Park SI, Oh J, Kim HJ, Kim JH, Wang EK, Hong IH, Ha YS, Choi TH, Jeong KS, Chang Y, Welch MJ, Jon S, Yoo J. Facile preparation of a hybrid nanoprobe for triple-modality optical/PET/MR imaging. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2010; 6:2863-2868. [PMID: 21104828 DOI: 10.1002/smll.201001418] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Affiliation(s)
- Jeong Chan Park
- Department of Molecular Medicine and Nuclear Medicine, Kyungpook National University, Daegu 700-422, Korea
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Preliminary evaluation of 177Lu-labeled knottin peptides for integrin receptor-targeted radionuclide therapy. Eur J Nucl Med Mol Imaging 2010; 38:613-22. [DOI: 10.1007/s00259-010-1684-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Accepted: 11/15/2010] [Indexed: 01/19/2023]
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Nielsen CH, Kimura RH, Withofs N, Tran PT, Miao Z, Cochran JR, Cheng Z, Felsher D, Kjær A, Willmann JK, Gambhir SS. PET imaging of tumor neovascularization in a transgenic mouse model with a novel 64Cu-DOTA-knottin peptide. Cancer Res 2010; 70:9022-30. [PMID: 21062977 DOI: 10.1158/0008-5472.can-10-1338] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Due to the high mortality of lung cancer, there is a critical need to develop diagnostic procedures enabling early detection of the disease while at a curable stage. Targeted molecular imaging builds on the positive attributes of positron emission tomography/computed tomography (PET/CT) to allow for a noninvasive detection and characterization of smaller lung nodules, thus increasing the chances of positive treatment outcome. In this study, we investigate the ability to characterize lung tumors that spontaneously arise in a transgenic mouse model. The tumors are first identified with small animal CT followed by characterization with the use of small animal PET with a novel 64Cu-1,4,7,10-tetra-azacylododecane-N,N',N'',N'''-tetraacetic acid (DOTA)-knottin peptide that targets integrins upregulated during angiogenesis on the tumor associated neovasculature. The imaging results obtained with the knottin peptide are compared with standard 18F-fluorodeoxyglucose (FDG) PET small animal imaging. Lung nodules as small as 3 mm in diameter were successfully identified in the transgenic mice by small animal CT, and both 64Cu-DOTA-knottin 2.5F and FDG were able to differentiate lung nodules from the surrounding tissues. Uptake and retention of the 64Cu-DOTA-knottin 2.5F tracer in the lung tumors combined with a low background in the thorax resulted in a statistically higher tumor to background (normal lung) ratio compared with FDG (6.01±0.61 versus 4.36±0.68; P<0.05). Ex vivo biodistribution showed 64Cu-DOTA-knottin 2.5F to have a fast renal clearance combined with low nonspecific accumulation in the thorax. Collectively, these results show 64Cu-DOTA-knottin 2.5F to be a promising candidate for clinical translation for earlier detection and improved characterization of lung cancer.
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Affiliation(s)
- Carsten H Nielsen
- Molecular Imaging Program at Stanford, Department of Radiology, Division of Oncology, Stanford University, Stanford, California 94305-5427, USA
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Detection of Cancer Metastases with a Dual-labeled Near-Infrared/Positron Emission Tomography Imaging Agent. Transl Oncol 2010; 3:307-217. [PMID: 20885893 DOI: 10.1593/tlo.10139] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Revised: 06/07/2010] [Accepted: 06/14/2010] [Indexed: 01/08/2023] Open
Abstract
UNLABELLED By dual labeling a targeting moiety with both nuclear and optical probes, the ability for noninvasive imaging and intraoperative guidance may be possible. Herein, the ability to detect metastasis in an immunocompetent animal model of human epidermal growth factor receptor 2 (HER-2)-positive cancer metastases using positron emission tomography (PET) and near-infrared (NIR) fluorescence imaging is demonstrated. METHODS ((64)Cu-DOTA)(n)-trastuzumab-(IRDye800)(m) was synthesized, characterized, and administered to female Balb/c mice subcutaneously inoculated with highly metastatic 4T1.2neu/R breast cancer cells. ((64)Cu-DOTA)(n)-trastuzumab-(IRDye800)(m) (150 µg, 150 µCi, m = 2, n = 2) was administered through the tail vein at weeks 2 and 6 after implantation, and PET/computed tomography and NIR fluorescence imaging were performed 24 hours later. Results were compared with the detection capabilities of F-18 fluorodeoxyglucose ((18)FDG-PET). RESULTS Primary tumors were visualized with (18)FDG and ((64)Cu-DOTA)(n)-trastuzumab-(IRDye800)(m), but resulting metastases were identified only with the dual-labeled imaging agent. (64)Cu-PET imaging detected lung metastases, whereas ex vivo NIR fluorescence showed uptake in regions of lung, skin, skeletal muscle, and lymph nodes, which corresponded with the presence of cancer cells as confirmed by histologic hematoxylin and eosin stains. In addition to detecting the agent in lymph nodes, the high signal-to-noise ratio from NIR fluorescence imaging enabled visualization of channels between the primary tumor and the axillary lymph nodes, suggesting a lymphatic route for trafficking cancer cells. Because antibody clearance occurs through the liver, we could not distinguish between nonspecific uptake and liver metastases. CONCLUSION ((64)Cu-DOTA)(n)-trastuzumab-(IRDye800)(m) may be an effective diagnostic imaging agent for staging HER-2-positive breast cancer patients and intraoperative resection.
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