1
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Wongso H, Yamasaki T, Kumata K, Ono M, Higuchi M, Zhang MR, Fulham MJ, Katsifis A, Keller PA. Design, Synthesis, and Biological Evaluation of Novel Fluorescent Probes Targeting the 18-kDa Translocator Protein. ChemMedChem 2021; 16:1902-1916. [PMID: 33631047 DOI: 10.1002/cmdc.202000984] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/22/2021] [Indexed: 12/20/2022]
Abstract
A series of fluorescent probes from the 6-chloro-2-phenylimidazo[1,2-a]pyridine-3-yl acetamides ligands featuring the 7-nitro-2-oxa-1,3-diazol-4-yl (NBD) moiety has been synthesized and biologically evaluated for their fluorescence properties and for their binding affinity to the 18-kDa translocator protein (TSPO). Spectroscopic studies including UV/Vis absorption and fluorescence measurements showed that the synthesized fluorescent probes exhibit favorable spectroscopic properties, especially in nonpolar environments. In vitro fluorescence staining in brain sections from lipopolysaccharide (LPS)-injected mice revealed partial colocalization of the probes with the TSPO. The TSPO binding affinity of the probes was measured on crude mitochondrial fractions separated from rat brain homogenates in a [11 C]PK11195 radioligand binding assay. All the new fluorescent probes demonstrated moderate to high binding affinity to the TSPO, with affinity (Ki ) values ranging from 0.58 nM to 3.28 μM. Taking these data together, we propose that the new fluorescent probes could be used to visualize the TSPO.
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Affiliation(s)
- Hendris Wongso
- School of Chemistry and Molecular Bioscience, and Molecular Horizons, University of Wollongong, Wollongong, NSW, 2522, Australia.,Center for Applied Nuclear Science and Technology, National Nuclear Energy Agency, Bandung, 40132, Indonesia
| | - Tomoteru Yamasaki
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Chiba, 263-8555, Japan
| | - Katsushi Kumata
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Chiba, 263-8555, Japan
| | - Maiko Ono
- Department of Functional Brain Imaging Research, National Institutes for Quantum and Radiological Science and Technology, Chiba, 263-8555, Japan
| | - Makoto Higuchi
- Department of Functional Brain Imaging Research, National Institutes for Quantum and Radiological Science and Technology, Chiba, 263-8555, Japan
| | - Ming-Rong Zhang
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Chiba, 263-8555, Japan
| | - Michael J Fulham
- Department of PET and Nuclear Medicine, Royal Prince Alfred Hospital, Camperdown, NSW, 2050, Australia
| | - Andrew Katsifis
- Department of PET and Nuclear Medicine, Royal Prince Alfred Hospital, Camperdown, NSW, 2050, Australia
| | - Paul A Keller
- School of Chemistry and Molecular Bioscience, and Molecular Horizons, University of Wollongong, Wollongong, NSW, 2522, Australia
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2
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Xie Q, Su M, Liu Y, Zhang D, Li Z, Bai M. Translocator protein (TSPO)-Targeted agents for photodynamic therapy of cancer. Photodiagnosis Photodyn Ther 2021; 34:102209. [PMID: 33561573 DOI: 10.1016/j.pdpdt.2021.102209] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 01/15/2021] [Accepted: 02/01/2021] [Indexed: 11/26/2022]
Abstract
Photodynamic therapy (PDT) is a clinically approved therapeutic strategy that combines a specific wavelength of light and light-activated photosensitizers (PSs). The usage of PDT for cancer treatment is often hampered by the lack of tumor selectivity of PSs, which may cause photodamage to surrounding normal tissues. Recently, translocator protein (TSPO) has attracted great interest as a tumor biomarker, whose expression correlates with tumor aggressiveness. In this study, we report the development of a series of novel TSPO-PSs based on quinazoline, pyrazolopyrimidine, and tetrahydrocarbazole structures. These TSPO-PSs bind to TSPO with nanomolar affinities and demonstrated efficient and target-specific PDT effect upon light irradiation. Therefore, they may have great potential in the treatment of tumors associated with high-TSPO expression.
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Affiliation(s)
- Qing Xie
- Vanderbilt University Institute of Imaging Sciences, Vanderbilt University Medical Center, 1161 21st Avenue South, Nashville, TN, 37232, USA
| | - Meng Su
- Vanderbilt University Institute of Imaging Sciences, Vanderbilt University Medical Center, 1161 21st Avenue South, Nashville, TN, 37232, USA
| | - Yang Liu
- Vanderbilt University Institute of Imaging Sciences, Vanderbilt University Medical Center, 1161 21st Avenue South, Nashville, TN, 37232, USA
| | - Dawei Zhang
- Vanderbilt University Institute of Imaging Sciences, Vanderbilt University Medical Center, 1161 21st Avenue South, Nashville, TN, 37232, USA; Department of Hepatobiliary Surgery, The Second Affiliated Hospital of Guangzhou Medical University, No. 250 East Changgang Road, Guangzhou, 510260, PR China
| | - Zhen Li
- Vanderbilt University Institute of Imaging Sciences, Vanderbilt University Medical Center, 1161 21st Avenue South, Nashville, TN, 37232, USA; Department of General Surgery, The Fourth Affiliated Hospital of China Medical University, No. 4 Chongshan East Road, Huanggu District, Shenyang, 110032, PR China
| | - Mingfeng Bai
- Vanderbilt University Institute of Imaging Sciences, Vanderbilt University Medical Center, 1161 21st Avenue South, Nashville, TN, 37232, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, 37232, USA; Vanderbilt Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.
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3
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Cohen AS, Li J, Hight MR, McKinley E, Fu A, Payne A, Liu Y, Zhang D, Xie Q, Bai M, Ayers GD, Tantawy MN, Smith JA, Revetta F, Washington MK, Shi C, Merchant N, Manning HC. TSPO-targeted PET and Optical Probes for the Detection and Localization of Premalignant and Malignant Pancreatic Lesions. Clin Cancer Res 2020; 26:5914-5925. [PMID: 32933996 DOI: 10.1158/1078-0432.ccr-20-1214] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 07/24/2020] [Accepted: 09/10/2020] [Indexed: 12/28/2022]
Abstract
PURPOSE Pancreatic cancer is among the most aggressive malignancies and is rarely discovered early. However, pancreatic "incidentalomas," particularly cysts, are frequently identified in asymptomatic patients through anatomic imaging for unrelated causes. Accurate determination of the malignant potential of cystic lesions could lead to life-saving surgery or spare patients with indolent disease undue risk. Current risk assessment of pancreatic cysts requires invasive sampling, with attendant morbidity and sampling errors. Here, we sought to identify imaging biomarkers of high-risk pancreatic cancer precursor lesions. EXPERIMENTAL DESIGN Translocator protein (TSPO) expression, which is associated with cholesterol metabolism, was evaluated in premalignant and pancreatic cancer lesions from human and genetically engineered mouse (GEM) tissues. In vivo imaging was performed with [18F]V-1008, a TSPO-targeted PET agent, in two GEM models. For image-guided surgery (IGS), V-1520, a TSPO ligand for near-IR optical imaging based upon the V-1008 pharmacophore, was developed and evaluated. RESULTS TSPO was highly expressed in human and murine pancreatic cancer. Notably, TSPO expression was associated with high-grade, premalignant intraductal papillary mucinous neoplasms (IPMNs) and pancreatic intraepithelial neoplasia (PanIN) lesions. In GEM models, [18F]V-1008 exhibited robust uptake in early pancreatic cancer, detectable by PET. Furthermore, V-1520 localized to premalignant pancreatic lesions and advanced tumors enabling real-time IGS. CONCLUSIONS We anticipate that combined TSPO PET/IGS represents a translational approach for precision pancreatic cancer care through discrimination of high-risk indeterminate lesions and actionable surgery.
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Affiliation(s)
- Allison S Cohen
- Vanderbilt Center for Molecular Probes, Vanderbilt University Medical Center, Nashville, Tennessee.,Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Jun Li
- Vanderbilt Center for Molecular Probes, Vanderbilt University Medical Center, Nashville, Tennessee.,Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Matthew R Hight
- Vanderbilt Center for Molecular Probes, Vanderbilt University Medical Center, Nashville, Tennessee.,Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Eliot McKinley
- Vanderbilt Center for Molecular Probes, Vanderbilt University Medical Center, Nashville, Tennessee.,Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee.,Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee
| | - Allie Fu
- Vanderbilt Center for Molecular Probes, Vanderbilt University Medical Center, Nashville, Tennessee.,Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Adria Payne
- Vanderbilt Center for Molecular Probes, Vanderbilt University Medical Center, Nashville, Tennessee.,Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Yang Liu
- Vanderbilt Center for Molecular Probes, Vanderbilt University Medical Center, Nashville, Tennessee.,Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Dawei Zhang
- Vanderbilt Center for Molecular Probes, Vanderbilt University Medical Center, Nashville, Tennessee.,Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Qing Xie
- Vanderbilt Center for Molecular Probes, Vanderbilt University Medical Center, Nashville, Tennessee.,Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Mingfeng Bai
- Vanderbilt Center for Molecular Probes, Vanderbilt University Medical Center, Nashville, Tennessee.,Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee.,Vanderbilt Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Gregory D Ayers
- Vanderbilt Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee.,Department of Biostatistics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Mohammed Noor Tantawy
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Jarrod A Smith
- Vanderbilt University Center for Structural Biology, Vanderbilt University, Nashville, Tennessee
| | - Frank Revetta
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - M Kay Washington
- Vanderbilt Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee.,Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Chanjuan Shi
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Nipun Merchant
- Vanderbilt Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - H Charles Manning
- Vanderbilt Center for Molecular Probes, Vanderbilt University Medical Center, Nashville, Tennessee. .,Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee.,Vanderbilt Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee
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4
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Li J, Smith JA, Dawson ES, Fu A, Nickels ML, Schulte ML, Manning HC. Optimized Translocator Protein Ligand for Optical Molecular Imaging and Screening. Bioconjug Chem 2017; 28:1016-1023. [PMID: 28156095 DOI: 10.1021/acs.bioconjchem.6b00711] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Translocator protein (TSPO) is a validated target for molecular imaging of a variety of human diseases and disorders. Given its involvement in cholesterol metabolism, TSPO expression is commonly elevated in solid tumors, including glioma, colorectal cancer, and breast cancer. TSPO ligands capable of detection by optical imaging are useful molecular tracers for a variety of purposes that range from quantitative biology to drug discovery. Leveraging our prior optimization of the pyrazolopyrimidine TSPO ligand scaffold for cancer imaging, we report herein a new generation of TSPO tracers with superior binding affinity and suitability for optical imaging and screening. In total, seven candidate TSPO tracers were synthesized and vetted in this study; the most promising tracer identified (29, Kd = 0.19 nM) was the result of conjugating a high-affinity TSPO ligand to a fluorophore used routinely in biological sciences (FITC) via a functional carbon linker of optimal length. Computational modeling suggested that an n-alkyl linker of eight carbons in length allows for positioning of the bulky fluorophore distal to the ligand binding domain and toward the solvent interface, minimizing potential ligand-protein interference. Probe 29 was found to be highly suitable for in vitro imaging of live TSPO-expressing cells and could be deployed as a ligand screening and discovery tool. Competitive inhibition of probe 29 quantified by fluorescence and 3H-PK11195 quantified by traditional radiometric detection resulted in equivalent affinity data for two previously reported TSPO ligands. This study introduces the utility of TSPO ligand 29 for in vitro imaging and screening and provides a structural basis for the development of future TSPO imaging ligands bearing bulky signaling moieties.
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Affiliation(s)
- Jun Li
- Interdisciplinary Materials Science Program, ∥Vanderbilt University Center for Structural Biology, and ■Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37232, United States.,Vanderbilt University Institute of Imaging Science (VUIIS), §Center for Molecular Probes, ⊥Department of Radiology and Radiological Sciences, #Department of Biochemistry, ¶Vanderbilt-Ingram Cancer Center (VICC), and ▽Department of Neurosurgery, Vanderbilt University Medical Center , Nashville, Tennessee 37232, United States
| | - Jarrod A Smith
- Interdisciplinary Materials Science Program, ∥Vanderbilt University Center for Structural Biology, and ■Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37232, United States.,Vanderbilt University Institute of Imaging Science (VUIIS), §Center for Molecular Probes, ⊥Department of Radiology and Radiological Sciences, #Department of Biochemistry, ¶Vanderbilt-Ingram Cancer Center (VICC), and ▽Department of Neurosurgery, Vanderbilt University Medical Center , Nashville, Tennessee 37232, United States
| | - Eric S Dawson
- Interdisciplinary Materials Science Program, ∥Vanderbilt University Center for Structural Biology, and ■Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37232, United States.,Vanderbilt University Institute of Imaging Science (VUIIS), §Center for Molecular Probes, ⊥Department of Radiology and Radiological Sciences, #Department of Biochemistry, ¶Vanderbilt-Ingram Cancer Center (VICC), and ▽Department of Neurosurgery, Vanderbilt University Medical Center , Nashville, Tennessee 37232, United States
| | - Allie Fu
- Interdisciplinary Materials Science Program, ∥Vanderbilt University Center for Structural Biology, and ■Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37232, United States.,Vanderbilt University Institute of Imaging Science (VUIIS), §Center for Molecular Probes, ⊥Department of Radiology and Radiological Sciences, #Department of Biochemistry, ¶Vanderbilt-Ingram Cancer Center (VICC), and ▽Department of Neurosurgery, Vanderbilt University Medical Center , Nashville, Tennessee 37232, United States
| | - Michael L Nickels
- Interdisciplinary Materials Science Program, ∥Vanderbilt University Center for Structural Biology, and ■Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37232, United States.,Vanderbilt University Institute of Imaging Science (VUIIS), §Center for Molecular Probes, ⊥Department of Radiology and Radiological Sciences, #Department of Biochemistry, ¶Vanderbilt-Ingram Cancer Center (VICC), and ▽Department of Neurosurgery, Vanderbilt University Medical Center , Nashville, Tennessee 37232, United States
| | - Michael L Schulte
- Interdisciplinary Materials Science Program, ∥Vanderbilt University Center for Structural Biology, and ■Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37232, United States.,Vanderbilt University Institute of Imaging Science (VUIIS), §Center for Molecular Probes, ⊥Department of Radiology and Radiological Sciences, #Department of Biochemistry, ¶Vanderbilt-Ingram Cancer Center (VICC), and ▽Department of Neurosurgery, Vanderbilt University Medical Center , Nashville, Tennessee 37232, United States
| | - H Charles Manning
- Interdisciplinary Materials Science Program, ∥Vanderbilt University Center for Structural Biology, and ■Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37232, United States.,Vanderbilt University Institute of Imaging Science (VUIIS), §Center for Molecular Probes, ⊥Department of Radiology and Radiological Sciences, #Department of Biochemistry, ¶Vanderbilt-Ingram Cancer Center (VICC), and ▽Department of Neurosurgery, Vanderbilt University Medical Center , Nashville, Tennessee 37232, United States
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5
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Zhang S, Yang L, Ling X, Shao P, Wang X, Edwards WB, Bai M. Tumor mitochondria-targeted photodynamic therapy with a translocator protein (TSPO)-specific photosensitizer. Acta Biomater 2015; 28:160-170. [PMID: 26432436 DOI: 10.1016/j.actbio.2015.09.033] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 09/10/2015] [Accepted: 09/28/2015] [Indexed: 12/20/2022]
Abstract
Photodynamic therapy (PDT) has been proven to be a minimally invasive and effective therapeutic strategy for cancer treatment. It can be used alone or as a complement to conventional cancer treatments, such as surgical debulking and chemotherapy. The mitochondrion is an attractive target for developing novel PDT agents, as it produces energy for cells and regulates apoptosis. Current strategy of mitochondria targeting is mainly focused on utilizing cationic photosensitizers that bind to the negatively charged mitochondria membrane. However, such an approach is lack of selectivity of tumor cells. To minimize the damage on healthy tissues and improve therapeutic efficacy, an alternative targeting strategy with high tumor specificity is in critical need. Herein, we report a tumor mitochondria-specific PDT agent, IR700DX-6T, which targets the 18kDa mitochondrial translocator protein (TSPO). IR700DX-6T induced apoptotic cell death in TSPO-positive breast cancer cells (MDA-MB-231) but not TSPO-negative breast cancer cells (MCF-7). In vivo PDT study suggested that IR700DX-6T-mediated PDT significantly inhibited the growth of MDA-MB-231 tumors in a target-specific manner. These combined data suggest that this new TSPO-targeted photosensitizer has great potential in cancer treatment. STATEMENT OF SIGNIFICANCE Photodynamic therapy (PDT) is an effective and minimally invasive therapeutic technique for treating cancers. Mitochondrion is an attractive target for developing novel PDT agents, as it produces energy to cells and regulates apoptosis. Current mitochondria targeted photosensitizers (PSs) are based on cationic molecules, which interact with the negatively charged mitochondria membrane. However, such PSs are not specific for cancerous cells, which may result in unwanted side effects. In this study, we developed a tumor mitochondria-targeted PS, IR700DX-6T, which binds to translocator protein (TSPO). This agent effectively induced apoptosis in TSPO-positive cancer cells and significantly inhibited tumor growth in TSPO-positive tumor-bearing mice. These combined data suggest that IR700DX-6T could become a powerful tool in the treatment of multiple cancers that upregulate TSPO.
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Affiliation(s)
- Shaojuan Zhang
- Molecular Imaging Laboratory, Department of Radiology, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Ling Yang
- Molecular Imaging Laboratory, Department of Radiology, University of Pittsburgh, Pittsburgh, PA 15219, USA
- Department of Cellular and Genetic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China
| | - Xiaoxi Ling
- Molecular Imaging Laboratory, Department of Radiology, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Pin Shao
- Molecular Imaging Laboratory, Department of Radiology, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Xiaolei Wang
- Molecular Imaging Laboratory, Department of Radiology, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - W Barry Edwards
- Molecular Imaging Laboratory, Department of Radiology, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Mingfeng Bai
- Molecular Imaging Laboratory, Department of Radiology, University of Pittsburgh, Pittsburgh, PA 15219, USA
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261, USA
- University of Pittsburgh Cancer Institute, Pittsburgh, PA 15232, USA
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6
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Samuelson LE, Anderson BM, Bai M, Dukes MJ, Hunt CR, Casey JD, Han Z, Papadopoulos V, Bornhop DJ. A self-internalizing mitochondrial TSPO targeting imaging probe for fluorescence, MRI and EM. RSC Adv 2014; 4:9003-9011. [PMID: 32051760 DOI: 10.1039/c3ra47161f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Advances in probes for cellular imaging have driven discoveries in biology and medicine. Primarily, antibodies and small molecules have been made for contrast enhancement of specific proteins. The development of new dendrimer-based tools offers opportunities to tune cellular internalization and targeting, image multiple modalities in the same molecule and explore therapeutics. The translocator protein (TSPO) offers an ideal target to develop dendrimer tools because it is well characterized and implicated in a number of disease states. The TSPO-targeted dendrimers reported here, primarily ClPhIQ-PAMAM-Gd-Liss, are cell membrane permeable nanoparticles that enable labeling of TSPO and provide contrast in fluorescence, electron microscopy and magnetic resonance imaging. The molecular binding affinity for TSPO was found to be 0.51 μM, 3 times greater than the monomeric agents previously demonstrated in our laboratory. The relaxivity per Gd3+ of the ClPhIQ23-PAMAM-Gd18 dendrimer was 7.7 and 8.0 mM-1 s-1 for r 1 and r 2 respectively, approximately double that of the clinically used monomeric Gd3+ chelates. In vitro studies confirmed molecular selectively for labeling TSPO in the mitochondria of C6 rat glioma and MDA-MB-231 cell lines. Fluorescence co-registration with Mitotracker Green® and increased contrast of osmium-staining in electron microscopy confirmed mitochondrial labeling of these TSPO-targeted agents. Taken collectively these experiments demonstrate the versatility of conjugation of our PAMAM dendrimeric chemistry to allow multi-modality agents to be prepared. These agents target organelles and use complementary imaging modalities in vitro, potentially allowing disease mechanism studies with high sensitivity and high resolution techniques.
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Affiliation(s)
- Lynn E Samuelson
- Department of Chemistry, The Vanderbilt Institute for Chemical Biology and Vanderbilt-Ingram Cancer Center, Vanderbilt University, VU Station B 351822 Nashville, Tennessee 37235-1822, USA
| | - Bernard M Anderson
- Department of Chemistry, The Vanderbilt Institute for Chemical Biology and Vanderbilt-Ingram Cancer Center, Vanderbilt University, VU Station B 351822 Nashville, Tennessee 37235-1822, USA
| | - Mingfeng Bai
- Department of Chemistry, The Vanderbilt Institute for Chemical Biology and Vanderbilt-Ingram Cancer Center, Vanderbilt University, VU Station B 351822 Nashville, Tennessee 37235-1822, USA
| | - Madeline J Dukes
- Department of Chemistry, The Vanderbilt Institute for Chemical Biology and Vanderbilt-Ingram Cancer Center, Vanderbilt University, VU Station B 351822 Nashville, Tennessee 37235-1822, USA
| | - Colette R Hunt
- Department of Chemistry, The Vanderbilt Institute for Chemical Biology and Vanderbilt-Ingram Cancer Center, Vanderbilt University, VU Station B 351822 Nashville, Tennessee 37235-1822, USA
| | - Jonathon D Casey
- Department of Chemistry, The Vanderbilt Institute for Chemical Biology and Vanderbilt-Ingram Cancer Center, Vanderbilt University, VU Station B 351822 Nashville, Tennessee 37235-1822, USA
| | - Zeqiu Han
- Department of Biochemistry &Molecular and Ceilular Biology, Georgetown University Medical Center, BSB Room 315, 3900 Reservoir Road NW, Washington, DC 20057, USA
| | - Vassilios Papadopoulos
- The Research Institute of the McGill University Health Centre, Departments of Medicine, Biochemistry, and Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Darryl J Bornhop
- Department of Chemistry, The Vanderbilt Institute for Chemical Biology and Vanderbilt-Ingram Cancer Center, Vanderbilt University, VU Station B 351822 Nashville, Tennessee 37235-1822, USA
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7
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Trapani A, Palazzo C, de Candia M, Lasorsa FM, Trapani G. Targeting of the Translocator Protein 18 kDa (TSPO): A Valuable Approach for Nuclear and Optical Imaging of Activated Microglia. Bioconjug Chem 2013; 24:1415-28. [DOI: 10.1021/bc300666f] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Adriana Trapani
- Department of Pharmacy and Drug
Sciences, University of Bari, Bari, 70125,
Italy
| | - Claudio Palazzo
- Department of Pharmacy and Drug
Sciences, University of Bari, Bari, 70125,
Italy
| | - Modesto de Candia
- Department of Pharmacy and Drug
Sciences, University of Bari, Bari, 70125,
Italy
| | | | - Giuseppe Trapani
- Department of Pharmacy and Drug
Sciences, University of Bari, Bari, 70125,
Italy
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8
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Loison S, Cottet M, Orcel H, Adihou H, Rahmeh R, Lamarque L, Trinquet E, Kellenberger E, Hibert M, Durroux T, Mouillac B, Bonnet D. Selective Fluorescent Nonpeptidic Antagonists For Vasopressin V2 GPCR: Application To Ligand Screening and Oligomerization Assays. J Med Chem 2012; 55:8588-602. [DOI: 10.1021/jm3006146] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Stéphanie Loison
- Laboratoire
d’Innovation
Thérapeutique, UMR7200 CNRS/Université de Strasbourg,
Faculté de Pharmacie, 74 route du Rhin, 67412 Illkirch, France
| | - Martin Cottet
- CNRS UMR 5203, INSERM U661,
and Université Montpellier I et II, Institut de Génomique
Fonctionnelle, Département de Pharmacologie Moléculaire,
141 rue de la Cardonille, 34094 Montpellier Cedex 5, France
| | - Hélène Orcel
- CNRS UMR 5203, INSERM U661,
and Université Montpellier I et II, Institut de Génomique
Fonctionnelle, Département de Pharmacologie Moléculaire,
141 rue de la Cardonille, 34094 Montpellier Cedex 5, France
| | - Hélène Adihou
- Laboratoire
d’Innovation
Thérapeutique, UMR7200 CNRS/Université de Strasbourg,
Faculté de Pharmacie, 74 route du Rhin, 67412 Illkirch, France
| | - Rita Rahmeh
- CNRS UMR 5203, INSERM U661,
and Université Montpellier I et II, Institut de Génomique
Fonctionnelle, Département de Pharmacologie Moléculaire,
141 rue de la Cardonille, 34094 Montpellier Cedex 5, France
| | - Laurent Lamarque
- Cisbio Bioassays, Parc Marcel
Boiteux, BP84175, 30200 Codolet, France
| | - Eric Trinquet
- Cisbio Bioassays, Parc Marcel
Boiteux, BP84175, 30200 Codolet, France
| | - Esther Kellenberger
- Laboratoire
d’Innovation
Thérapeutique, UMR7200 CNRS/Université de Strasbourg,
Faculté de Pharmacie, 74 route du Rhin, 67412 Illkirch, France
| | - Marcel Hibert
- Laboratoire
d’Innovation
Thérapeutique, UMR7200 CNRS/Université de Strasbourg,
Faculté de Pharmacie, 74 route du Rhin, 67412 Illkirch, France
| | - Thierry Durroux
- CNRS UMR 5203, INSERM U661,
and Université Montpellier I et II, Institut de Génomique
Fonctionnelle, Département de Pharmacologie Moléculaire,
141 rue de la Cardonille, 34094 Montpellier Cedex 5, France
| | - Bernard Mouillac
- CNRS UMR 5203, INSERM U661,
and Université Montpellier I et II, Institut de Génomique
Fonctionnelle, Département de Pharmacologie Moléculaire,
141 rue de la Cardonille, 34094 Montpellier Cedex 5, France
| | - Dominique Bonnet
- Laboratoire
d’Innovation
Thérapeutique, UMR7200 CNRS/Université de Strasbourg,
Faculté de Pharmacie, 74 route du Rhin, 67412 Illkirch, France
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9
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Wyatt SK, Manning HC, Bai M, Ehtesham M, Mapara KY, Thompson RC, Bornhop DJ. Preclinical molecular imaging of the translocator protein (TSPO) in a metastases model based on breast cancer xenografts propagated in the murine brain. Curr Mol Med 2012; 12:458-66. [PMID: 22348613 DOI: 10.2174/156652412800163361] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 01/09/2012] [Accepted: 02/02/2012] [Indexed: 01/14/2023]
Abstract
Previous studies have demonstrated the feasibility of translocator protein (TSPO) imaging to visualize and quantify human breast adenocarcinoma (MDA-MB-231) cells in vivo using a TSPO-targeted near-infrared (NIR) probe (NIR-conPK11195). This study aimed to extend the use of the TSPO-targeted probe to a more biologically relevant and clinically important tumor microenvironment as well as to assess our ability to longitudinally detect the presence and progression of breast cancer cells in the brain. The in vivo biodistribution and accumulation of NIR-conPK11195 and free (unconjugated) NIR dye were quantitatively evaluated in intracranial MDA-MB-231-bearing mice and non-tumor-bearing control mice longitudinally once a week from two to five weeks post-inoculation. The in vivo time-activity curves illustrate distinct clearance profiles for NIR-conPK11195 and free NIR dye, resulting in preferential accumulation of the TSPO-targeted probe in the intracranial tumor bearing hemisphere (TBH) with significant tumor contrast over normal muscle tissue (p < 0.005 at five weeks; p < 0.01 at four weeks). In addition, the TSPO-labeled TBHs demonstrated significant contrast over the TBHs of mice injected with free NIR dye (p < 0.001 at four and five weeks) as well as over the TSPO-labeled non-tumor-bearing hemispheres (NTBHs) of control mice (p < 0.005 at four and five weeks). Overall, TSPO-targeted molecular imaging appears useful for visualizing and quantifying breast cancer xenografts propagated in the murine brain and may assist in preclinical detection, diagnosis and monitoring of metastatic disease as well as drug discovery. Furthermore, these results indicate it should be possible to perform TSPO-imaging of breast cancer cells in the brain using radiolabeled TSPO-targeted agents, particularly in light of the fact that [11C]-labeled TSPO probes such as [11C]-PK 11195 have been successfully used to image gliomas in the clinic.
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Affiliation(s)
- Shelby K Wyatt
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA
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Bai M, Achilefu S. Synthesis and spectroscopy of near infrared fluorescent dyes for investigating dichromic fluorescence. Bioorg Med Chem Lett 2010; 21:280-4. [PMID: 21106373 DOI: 10.1016/j.bmcl.2010.11.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Revised: 10/30/2010] [Accepted: 11/02/2010] [Indexed: 11/24/2022]
Abstract
We developed a series of near infrared (NIR) cyanine dyes to study dichromic fluorescence phenomenon, which provides new protocols for in vivo optical imaging. Preliminary spectroscopic studies show that dichromic fluorescence correlates with structural symmetry. This feature suggests the potential use of dichromic fluorescent molecules to study biological processes that can alter the structural symmetry of the molecular probes.
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Affiliation(s)
- Mingfeng Bai
- Department of Radiology, Washington University, 4525 Scott Avenue, St Louis, MO 63110, United States
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Gao F, Liu J, Yang L, Wang Q, Li H, Zhang S. Synthesis and Spectral Tuning of Novel Triphenylamine-Based Derivatives Containing Electron Donor-Acceptor Groups. CHINESE J CHEM 2010. [DOI: 10.1002/cjoc.201090177] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Molecular imaging of the translocator protein (TSPO) in a pre-clinical model of breast cancer. Mol Imaging Biol 2009; 12:349-58. [PMID: 19949989 DOI: 10.1007/s11307-009-0270-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Revised: 05/20/2009] [Accepted: 05/29/2009] [Indexed: 10/20/2022]
Abstract
PURPOSE To quantitatively evaluate the utility of a translocator protein (TSPO)-targeted near-infrared (NIR) probe (NIR-conPK11195) for in vivo molecular imaging of TSPO in breast cancer. PROCEDURES NIR-conPK11195 uptake and TSPO-specificity were validated in TSPO-expressing human breast adenocarcinoma cells (MDA-MB-231). In vivo NIR-conPK11195 biodistribution and accumulation were quantitatively evaluated in athymic nude mice bearing MDA-MB-231 xenografts. RESULTS Fluorescence micrographs illustrated intracellular labeling of MDA-MB-231 cells by NIR-conPK11195. Quantitative uptake and competition assays demonstrated dose-dependent (p < 0.001) and TSPO-specific (p < 0.001) NIR-conPK11195 uptake. In vivo, NIR-conPK11195 preferentially labeled MDA-MB-231 tumors with an 11-fold (p < 0.001) and 7-fold (p < 0.001) contrast enhancement over normal tissue and unconjugated NIR dye, respectively. CONCLUSIONS NIR-conPK11195 appears to be a promising TSPO-targeted molecular imaging agent for visualization and quantification of breast cancer cells in vivo. This research represents the first study to demonstrate the feasibility of TSPO imaging as an alternative breast cancer imaging approach.
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Samuelson LE, Dukes MJ, Hunt CR, Casey JD, Bornhop DJ. TSPO targeted dendrimer imaging agent: synthesis, characterization, and cellular internalization. Bioconjug Chem 2009; 20:2082-9. [PMID: 19863077 PMCID: PMC3038571 DOI: 10.1021/bc9002053] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
While it has become common practice for dendrimers to deliver imaging and therapeutic agents, there are few reported examples of cellular internalization of dendrimers. Moreover, targeting of dendrimers to the mitochondria in cells has not yet been reported. Previously, we have delivered small molecule imaging agents into glioma and breast cancer cells by targeting the translocator protein (TSPO; formerly known as the peripheral benzodiazepine receptor or PBR) with a family of high-affinity conjugable ligands. The 18 kDa multimeric TSPO is expressed in steroid-producing cells, primarily on the outer mitochondrial membrane. This protein is a prime candidate for molecular targeting because tumors and other disease-related cells contain high densities of TSPO. Here, we present the synthesis, characterization, and cellular internalization into C6 rat glioma cells of a TSPO targeted dendrimer imaging agent.
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Affiliation(s)
- Lynn E. Samuelson
- Department of Chemistry, The Vanderbilt Institute for Chemical Biology and Vanderbilt-Ingram Cancer Center, Vanderbilt University, VU Station B 351822 Nashville, Tennessee 37235-1822
| | - Madeline J. Dukes
- Department of Chemistry, The Vanderbilt Institute for Chemical Biology and Vanderbilt-Ingram Cancer Center, Vanderbilt University, VU Station B 351822 Nashville, Tennessee 37235-1822
| | - Colette R. Hunt
- Department of Chemistry, The Vanderbilt Institute for Chemical Biology and Vanderbilt-Ingram Cancer Center, Vanderbilt University, VU Station B 351822 Nashville, Tennessee 37235-1822
| | - Jonathan D. Casey
- Department of Chemistry, The Vanderbilt Institute for Chemical Biology and Vanderbilt-Ingram Cancer Center, Vanderbilt University, VU Station B 351822 Nashville, Tennessee 37235-1822
| | - Darryl J. Bornhop
- Department of Chemistry, The Vanderbilt Institute for Chemical Biology and Vanderbilt-Ingram Cancer Center, Vanderbilt University, VU Station B 351822 Nashville, Tennessee 37235-1822
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Bai M, Rone MB, Papadopoulos V, Bornhop DJ. A novel functional translocator protein ligand for cancer imaging. Bioconjug Chem 2007; 18:2018-23. [PMID: 17979225 DOI: 10.1021/bc700251e] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The translocator protein (TSPO) is an attractive target for tumor imaging due to its up-regulation in numerous cancer cell types. Here, we report a series of functional TSPO ligands, n-TSPOmbb732, which can be conjugated to a variety of signaling moieties and are widely applicable in TSPO-targeted molecular imaging. Two fluorescent dye-labeled 6-TSPOmbb732 displayed nanomolar binding affinities to TSPO and were successfully imaged in vitro.
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Affiliation(s)
- Mingfeng Bai
- Department of Chemistry, Vanderbilt University, VU Station B 351822, Nashville, TN 37235-1822, USA
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