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Wang Z, Ye M, Ma D, Shen J, Fang F. Engineering of 177Lu-labeled gold encapsulated into dendrimeric nanomaterials for the treatment of lung cancer. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2021; 33:197-211. [PMID: 34686102 DOI: 10.1080/09205063.2021.1982446] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
As a novel type of theranostic radioactive agents, 177Lu-labeled nanomaterials conjugated to macromolecules have been described. The study aimed to fabricate PAMAM-G4-(177Lu-dendrimer)-bombesin-folate in the dendrimeric cavity, assess the radiopharmaceutical ability for specifically targeted radiotherapy and simultaneously detects gastrin-releasing peptide receptors (GRPR) and folate receptors (FRs) overexpressed in lung carcinoma cells, respectively. In an aqueous-basic media, p-SCN-benzyl-DOTA was conjugated to the dendrimer. This dendrimer was formed by activating the carboxylic acid groups of DOTA-folic acid and bombesin with HATU and conjugating them to develop the dendrimer. As part of this process, the conjugate was combined with 1% HAuCl4, added NaBH4 and filtered by ultrafiltration. Infrared, UV-Vis, TEM analysis, dynamic light scattering (DLS), and fluorescence spectroscopy were employed to observe the composition of the fabricated sample. Radio-labeled 177LuCl3 was used to label the conjugate, which was then evaluated using the radio-HPLC method. Findings demonstrated dendrimeric functionalization with remarkable radiochemical composition purity up to >96%. Because of fluorescence studies, it was determined that the occurrence of AuNMs in the dendrimeric cavities gives beneficial photo-physical characteristics to the radiopharmaceutical for bio-imaging. HEL-299 lung cancer cells exhibited a selective absorption of the drug (%). It might be helpful as nuclear and optical imaging agents for lung cancers that overexpress FRs and GRPR and as a specific target for radiation therapy if combined with folate-bombesin.
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Affiliation(s)
- Zheng Wang
- Department of Cardiothoracic Surgery, Taizhou Hospital of Zhejiang Province, Taizhou, China
| | - Minhua Ye
- Department of Cardiothoracic Surgery, Taizhou Hospital of Zhejiang Province, Taizhou, China
| | - Dehua Ma
- Department of Cardiothoracic Surgery, Taizhou Hospital of Zhejiang Province, Taizhou, China
| | - Jianfei Shen
- Department of Cardiothoracic Surgery, Taizhou Hospital of Zhejiang Province, Taizhou, China
| | - Fang Fang
- Operating Room, Taizhou Hospital of Zhejiang Province, Taizhou, China
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Abstract
Single photon emission computed tomography (SPECT) is the state-of-the-art imaging modality in nuclear medicine despite the fact that only a few new SPECT tracers have become available in the past 20 years. Critical for the future success of SPECT is the design of new and specific tracers for the detection, localization, and staging of a disease and for monitoring therapy. The utility of SPECT imaging to address oncologic questions is dependent on radiotracers that ideally exhibit excellent tissue penetration, high affinity to the tumor-associated target structure, specific uptake and retention in the malignant lesions, and rapid clearance from non-targeted tissues and organs. In general, a target-specific SPECT radiopharmaceutical can be divided into two main parts: a targeting biomolecule (e.g., peptide, antibody fragment) and a γ-radiation-emitting radionuclide (e.g., 99mTc, 123I). If radiometals are used as the radiation source, a bifunctional chelator is needed to link the radioisotope to the targeting entity. In a rational SPECT tracer design, these single components have to be critically evaluated in order to achieve a balance among the demands for adequate target binding, and a rapid clearance of the radiotracer. The focus of this chapter is to depict recent developments of tumor-targeted SPECT radiotracers for imaging of cancer diseases. Possibilities for optimization of tracer design and potential causes for design failure are discussed and highlighted with selected examples.
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Nurunnabi M, Khatun Z, Badruddoza AZM, McCarthy JR, Lee YK, Huh KM. Biomaterials and Bioengineering Approaches for Mitochondria and Nuclear Targeting Drug Delivery. ACS Biomater Sci Eng 2019. [DOI: 10.1021/acsbiomaterials.8b01615] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Md Nurunnabi
- Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02129 United States
| | - Zehedina Khatun
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts 02111 United States
| | - Abu Zayed Md Badruddoza
- Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond, Virginia 23219 United States
| | - Jason R. McCarthy
- Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02129 United States
| | - Yong-kyu Lee
- Department of Chemical and Biological Engineering, Korea National University of Transportation, Chungju 380-706, Republic of Korea
| | - Kang Moo Huh
- Department of Polymer Science and Engineering, Chungnam National University, Daejeon 305-764, Republic of Korea
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Papagiannopoulou D. Technetium-99m radiochemistry for pharmaceutical applications. J Labelled Comp Radiopharm 2017; 60:502-520. [PMID: 28618064 DOI: 10.1002/jlcr.3531] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 06/08/2017] [Accepted: 06/08/2017] [Indexed: 12/14/2022]
Abstract
Technetium-99m (99m Tc) is a widely used radionuclide, and the development of 99m Tc imaging agents continues to be in demand. This overview discusses basic principles of 99m Tc radiopharmaceutical preparation and design and focuses on the 99m Tc radiochemistry relevant to its pharmaceutical applications. The 99m Tc complexes are described based on the most typical examples in each category, keeping up with the state-of-the-art in the field. In addition, the main current strategies to develop targeted 99m Tc radiopharmaceuticals are summarized.
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Affiliation(s)
- Dionysia Papagiannopoulou
- Department of Pharmaceutical Chemistry, School of Pharmacy, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
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De K, Banerjee I, Sinha S, Ganguly S. Synthesis and exploration of novel radiolabeled bombesin peptides for targeting receptor positive tumor. Peptides 2017; 89:17-34. [PMID: 28088445 DOI: 10.1016/j.peptides.2017.01.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 12/16/2016] [Accepted: 01/04/2017] [Indexed: 11/19/2022]
Abstract
Increasing evidence of peptide receptor overexpression in various cancer cells, warrant the development of receptor specific radiolabeled peptides for molecular imaging and therapy in nuclear medicine. Gastrin-releasing-peptide (GRP) receptor, are overexpressed in a variety of human cancer cells. The present study report the synthesis and biological evaluation of new bombesin (BBN) analogs, HYNIC-Asp-[Phe13]BBN(7-13)-NH-CH2-CH2-CH3:BA1, HYNIC-Pro-[Tyr13Met14]BBN(7-14)NH2:BA2 as prospective tumor imaging agent with compare to BBN(7-14)NH2:BS as standard. The pharmacophores were radiolabeled in high yields with 99mTc, characterized for their stability in serum and saline, cysteine/histidine and were found to be substantially stable. Internalization/externalization and receptor binding studies were assessed using MDA-MB-231 cells and showed high receptor binding-affinity and favourable internalization. Fluorescence studies revealed that BA1 changed the morphology of the cells and could localize in the nucleus more effectively than BA2/BS. Cell-viability studies displayed substantial antagonistic and nuclear-internalization effect of BA1. BA1 also exhibited antiproliferative effect on MDA-MB-231 cell by inducing apoptosis. In vivo behaviour of the radiopeptides was evaluated in GRP receptor positive tumor bearing mice. The 99mTc-BA1/99mTc-BA2 demonstrated rapid blood/urinary clearance through the renal pathway and comparatively more significant tumor uptake image and favourable tumor-to-non-target ratios provided by 99mTc-BA1. The specificity of the in vivo uptake was confirmed by co-injection with BS. Moreover, 99mTc-BA1 provided a much clearer tumor image in scintigraphic studies than others. Thus the combination of favourable in vitro and in vivo properties renders BA1 as more potential antagonist bombesin-peptide for targeting GRP-receptor positive tumor. These properties are encouraging to carry out further experiments for non-invasive receptor targeting potential diagnostinc and therapeutic agent for tumors.
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Affiliation(s)
- Kakali De
- Infectious Diseases and Immunology Division (Nuclear Medicine Laboratory), CSIR-Indian Institute of Chemical Biology, 4 Raja S C Mullick Road, Kolkata, 700032, West Bengal, India.
| | - Indranil Banerjee
- Infectious Diseases and Immunology Division (Nuclear Medicine Laboratory), CSIR-Indian Institute of Chemical Biology, 4 Raja S C Mullick Road, Kolkata, 700032, West Bengal, India
| | - Samarendu Sinha
- Regional Radiation Medicine Center, Thakurpukur Cancer Center and Welfare Home Campus, Kolkata, 700 063, India
| | - Shantanu Ganguly
- Regional Radiation Medicine Center, Thakurpukur Cancer Center and Welfare Home Campus, Kolkata, 700 063, India
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Bromelain-Functionalized Multiple-Wall Lipid-Core Nanocapsules: Formulation, Chemical Structure and Antiproliferative Effect Against Human Breast Cancer Cells (MCF-7). Pharm Res 2016; 34:438-452. [PMID: 27981451 DOI: 10.1007/s11095-016-2074-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 11/28/2016] [Indexed: 12/20/2022]
Abstract
PURPOSE This study was conducted a promising approach to surface functionalization developed for lipid-core nanocapsules and the merit to pursue new strategies to treat solid tumors. METHODS Bromelain-functionalized multiple-wall lipid-core nanocapsules (Bro-MLNC-Zn) were produced by self-assembling following three steps of interfacial reactions. Physicochemical and structural characteristics, in vitro proteolytic activity (casein substrate) and antiproliferative activity (breast cancer cells, MCF-7) were determined. RESULTS Bro-MLNC-Zn had z-average diameter of 135 nm and zeta potential of +23 mV. The complex is formed by a Zn-N chemical bond and a chelate with hydroxyl and carboxyl groups. Bromelain complexed at the nanocapsule surface maintained its proteolytic activity and showed anti-proliferative effect against human breast cancer cells (MCF-7) (72.6 ± 1.2% at 1.250 μg mL-1 and 65.5 ± 5.5% at 0.625 μg mL-1). Comparing Bro-MLNC-Zn and bromelain solution, the former needed a dose 160-folds lower than the latter for a similar effect. Tripan blue dye assay corroborated the results. CONCLUSIONS The surface functionalization approach produced an innovative formulation having a much higher anti-proliferative effect than the bromelain solution, even though both in vitro proteolytic activity were similar, opening up a great opportunity for further studies in nanomedicine.
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Synthesis, characterization and biological evaluation of (99m)Tc/Re-tricarbonyl quinolone complexes. J Inorg Biochem 2015; 160:94-105. [PMID: 26795497 DOI: 10.1016/j.jinorgbio.2015.12.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 11/26/2015] [Accepted: 12/16/2015] [Indexed: 11/24/2022]
Abstract
New rhenium(I) tricarbonyl complexes with the quinolone antimicrobial agents oxolinic acid (Hoxo) and enrofloxacin (Herx) and containing methanol, triphenylphosphine (PPh3) or imidazole (im) as unidentate co-ligands, were synthesized and characterized. The crystal structure of complex [Re(CO)3(oxo)(PPh3)]∙0.5MeOH was determined by X-ray crystallography. The deprotonated quinolone ligands are bound bidentately to rhenium(I) ion through the pyridone oxygen and a carboxylate oxygen. The binding of the rhenium complexes to calf-thymus DNA (CT DNA) was monitored by UV spectroscopy, viscosity measurements and competitive studies with ethidium bromide; intercalation was suggested as the most possible mode and the DNA-binding constants of the complexes were calculated. The rhenium complex [Re(CO)3(erx)(im)] was assayed for its topoisomerase IIα inhibition activity and was found to be active at 100μM concentration. The interaction of the rhenium complexes with human or bovine serum albumin was investigated by fluorescence emission spectroscopy (through the tryptophan quenching) and the corresponding binding constants were determined. The tracer complex [(99m)Tc(CO)3(erx)(im)] was synthesized and identified by comparative HPLC analysis with the rhenium analog. The (99m)Tc complex was found to be stable in solution. Upon injection in healthy mice, fast tissue clearance of the (99m)Tc complex was observed, while both renal and hepatobiliary excretion took place. Preliminary studies in human K-562 erythroleukemia cells showed cellular uptake of the (99m)Tc tracer with distribution primarily in the cytoplasm and the mitochondria and less in the nucleus. These preliminary results indicate that the quinolone (99m)Tc/Re complexes show promise to be further evaluated as imaging or therapeutic agents.
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Vassiliadis V, Triantis C, Raptopoulou CP, Psycharis V, Terzis A, Pirmettis I, Papadopoulos MS, Papagiannopoulou D. Synthesis, structural characterization and radiochemistry of “2+1” fac-[99mTc/Re(CO)3(L)(2-mercaptopyridine)] complexes, where L is phosphine or isocyanide. Polyhedron 2014. [DOI: 10.1016/j.poly.2014.07.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Connell TU, Hayne DJ, Ackermann U, Tochon-Danguy HJ, White JM, Donnelly PS. Rhenium and technetium tricarbonyl complexes of 1,4-Substituted pyridyl-1,2,3-triazole bidentate ‘click’ ligands conjugated to a targeting RGD peptide. J Labelled Comp Radiopharm 2013; 57:262-9. [DOI: 10.1002/jlcr.3169] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 10/29/2013] [Indexed: 12/28/2022]
Affiliation(s)
- Timothy U. Connell
- School of Chemistry, Bio21 Molecular Science and Biotechnology Institute; University of Melbourne; Melbourne 3010 Australia
| | - David J. Hayne
- School of Chemistry, Bio21 Molecular Science and Biotechnology Institute; University of Melbourne; Melbourne 3010 Australia
| | - Uwe Ackermann
- Centre for PET; Austin Health; Melbourne 3084 Australia
| | | | - Jonathan M. White
- School of Chemistry, Bio21 Molecular Science and Biotechnology Institute; University of Melbourne; Melbourne 3010 Australia
| | - Paul S. Donnelly
- School of Chemistry, Bio21 Molecular Science and Biotechnology Institute; University of Melbourne; Melbourne 3010 Australia
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Isostructural Nuclear and Luminescent Probes Derived From Stabilized [2 + 1] Rhenium(I)/Technetium(I) Organometallic Complexes. Inorg Chem 2013; 52:13521-8. [PMID: 24228697 DOI: 10.1021/ic401972g] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Triantis C, Tsotakos T, Tsoukalas C, Sagnou M, Raptopoulou C, Terzis A, Psycharis V, Pelecanou M, Pirmettis I, Papadopoulos M. Synthesis and characterization of fac-[M(CO)3(P)(OO)] and cis-trans-[M(CO)2(P)2(OO)] complexes (M = Re, (99m)Tc) with acetylacetone and curcumin as OO donor bidentate ligands. Inorg Chem 2013; 52:12995-3003. [PMID: 24199833 DOI: 10.1021/ic401503b] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The synthesis and characterization of neutral mixed ligand complexes fac-[M(CO)3(P)(OO)] and cis-trans-[M(CO)2(P)2(OO)] (M = Re, (99m)Tc), with deprotonated acetylacetone or curcumin as the OO donor bidentate ligands and a phosphine (triphenylphosphine or methyldiphenylphosphine) as the monodentate P ligand, is described. The complexes were synthesized through the corresponding fac-[M(CO)3(H2O)(OO)] (M = Re, (99m)Tc) intermediate aqua complex. In the presence of phosphine, replacement of the H2O molecule of the intermediate complex at room temperature generates the neutral tricarbonyl monophosphine fac-[Re(CO)3(P)(OO)] complex, while under reflux conditions further replacement of the trans to the phosphine carbonyl generates the new stable dicarbonyl bisphosphine complex cis-trans-[Re(CO)2(P)2(OO)]. The Re complexes were fully characterized by elemental analysis, spectroscopic methods, and X-ray crystallography showing a distorted octahedral geometry around Re. Both the monophosphine and the bisphosphine complexes of curcumin show selective binding to β-amyloid plaques of Alzheimer's disease. At the (99m)Tc tracer level, the same type of complexes, fac-[(99m)Tc(CO)3(P)(OO)] and cis-trans-[(99m)Tc(CO)2(P)2(OO)], are formed introducing new donor combinations for (99m)Tc(I). Overall, β-diketonate and phosphine constitute a versatile ligand combination for Re(I) and (99m)Tc(I), and the successful employment of the multipotent curcumin as β-diketone provides a solid example of the pharmacological potential of this system.
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Affiliation(s)
- Charalampos Triantis
- Institute of Nuclear and Radiological Sciences and Technology, Energy and Safety, ‡Institute of Biosciences & Applications, and §Institute of Advanced Materials, Physicochemical Processes, Nanotechnology and Microsystems, Department of Materials Science, National Centre for Scientific Research "Demokritos" , 15310 Athens, Greece
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Kluba CA, Bauman A, Valverde IE, Vomstein S, Mindt TL. Dual-targeting conjugates designed to improve the efficacy of radiolabeled peptides. Org Biomol Chem 2012; 10:7594-602. [PMID: 22898743 DOI: 10.1039/c2ob26127h] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Radiolabeled regulatory peptides are useful tools in nuclear medicine for the diagnosis (imaging) and therapy of cancer. The specificity of the peptides towards GPC receptors, which are overexpressed by cancer cells, and their favorable pharmacokinetic profile make them ideal vectors to transport conjugated radionuclides to tumors and metastases. However, after internalization of the radiopeptide into cancer cells and tumors, a rapid washout of a substantial fraction of the delivered radioactivity is often observed. This phenomenon may represent a limitation of radiopeptides for clinical applications. Here, we report the synthesis, radiolabeling, stability, and in vitro evaluation of a novel, dual-targeting peptide radioconjugate designed to enhance the cellular retention of radioactivity. The described trifunctional conjugate is comprised of a Tc-99m SPECT reporter probe, a cell membrane receptor-specific peptide, and a second targeting entity directed towards mitochondria. While the specificity of the first generation of dual-targeting conjugates towards its extracellular target was demonstrated, intracellular targeting could not be confirmed probably due to non-specific binding or hindered passage through the membrane of the organelle. The work presented describes a novel approach with potential to improve the efficacy of radiopharmaceuticals by enhancing the intracellular retention of radioactivity.
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Affiliation(s)
- Christiane A Kluba
- University of Basel Hospital, Department of Radiology and Nuclear Medicine, Division of Radiological Chemistry, Petersgraben 4, 4031 Basel, Switzerland
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Morais GR, Paulo A, Santos I. Organometallic Complexes for SPECT Imaging and/or Radionuclide Therapy. Organometallics 2012. [DOI: 10.1021/om300501d] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Goreti Ribeiro Morais
- Unidade de Ciências
Quı́micas e Radiofarmacêuticas, Instituto
Tecnológico e Nuclear, Instituto Superior Técnico, Universidade Técnica de Lisboa, Estrada Nacional
10, 2686-953, Sacavém, Portugal
| | - António Paulo
- Unidade de Ciências
Quı́micas e Radiofarmacêuticas, Instituto
Tecnológico e Nuclear, Instituto Superior Técnico, Universidade Técnica de Lisboa, Estrada Nacional
10, 2686-953, Sacavém, Portugal
| | - Isabel Santos
- Unidade de Ciências
Quı́micas e Radiofarmacêuticas, Instituto
Tecnológico e Nuclear, Instituto Superior Técnico, Universidade Técnica de Lisboa, Estrada Nacional
10, 2686-953, Sacavém, Portugal
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Abstract
Technetium and Rhenium are the two lower elements in the manganese triad. Whereas rhenium is known as an important part of high resistance alloys, technetium is mostly known as a cumbersome product of nuclear fission. It is less known that its metastable isotope 99mTc is of utmost importance in nuclear medicine diagnosis. The technical application of elemental rhenium is currently complemented by investigations of its isotope 188Re , which could play a central role in the future for internal, targeted radiotherapy. This article will briefly describe the basic principles behind diagnostic methods with radionuclides for molecular imaging, review the 99mTc -based radiopharmaceuticals currently in clinical routine and focus on the chemical challenges and current developments towards improved, radiolabeled compounds for diagnosis and therapy in nuclear medicine.
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Affiliation(s)
- ROGER ALBERTO
- University of Zürich, Institute of Inorganic Chemistry, Winterthurerstr. 190, CH-8057 Zürich, Switzerland
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Santoro G, Blacque O, Zobi F. Post-protein binding metal-mediated coupling of an acridine orange-based fluorophore. Metallomics 2012; 4:253-9. [PMID: 22310805 DOI: 10.1039/c2mt00175f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The HEW lysozyme (Lys) and the fac-[Re(CO)(3)(H(2)O)(3)](+) complex (1) are used as a simple model system for the description of a new approach to the labelling polypeptides with fluorescent tags. The strategy takes advantage of the reaction of an acridine orange-based fluorophore (AO) with the non-native metal fragment 1 hybridized on the enzyme. A synthetic methodology for the quantitative metallation of the protein is first described and it is then shown that the exogenous metal complex can be exploited for the coupling of the fluorescent probe. All Lys-derived species were characterized by various spectroscopic techniques. It is shown that the approach does not significantly alter the activity of the final fluorescent metallo-protein conjugate (Lys2). The accumulation of Lys2 on Micrococcus lysodeikticus bacteria was observed via confocal laser scanning microscopy.
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Affiliation(s)
- Giuseppe Santoro
- Institute of Inorganic Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
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Esteves T, Marques F, Paulo A, Rino J, Nanda P, Smith CJ, Santos I. Nuclear targeting with cell-specific multifunctional tricarbonyl M(I) (M is Re, (99m)Tc) complexes: synthesis, characterization, and cell studies. J Biol Inorg Chem 2011; 16:1141-53. [PMID: 21706254 DOI: 10.1007/s00775-011-0803-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Accepted: 06/01/2011] [Indexed: 11/29/2022]
Abstract
Auger-emitting radionuclides such as (99m)Tc have been the focus of recent studies aiming at finding more selective therapeutic approaches. To explore the potential usefulness of (99m)Tc as an Auger emitter, we have synthesized and biologically evaluated novel multifunctional structures comprising (1) a pyrazolyl-diamine framework bearing a set of donor atoms to stabilize the [M(CO)(3)](+) (M is Re, (99m)Tc) core; (2) a DNA intercalating moiety of the acridine orange type to ensure close proximity of the radionuclide to DNA and to follow the internalization and subcellular trafficking of the compounds by confocal fluorescence microscopy; and (3) a bombesin (BBN) analogue of the type X-BBN[7-14] (where X is SGS, GGG) to provide specificity towards cells expressing the gastrin releasing peptide receptor (GRPr). Of the evaluated (99m)Tc complexes, Tc ( 3 ) containing the GGG-BBN[7-14] peptide showed the highest cellular internalization in GRPr-positive PC3 human prostate tumor cells, presenting a remarkably high nuclear uptake in the same cell line. Live-cell confocal imaging microscopy studies with the congener Re complex, Re ( 3 ), showed a considerable accumulation of fluorescence in the nucleus, with kinetics of uptake similar to that exhibited by Tc ( 3 ). Together, these data show that the acridine orange intercalator and the metal fragment are colocalized in the nucleus, which indicates that they remain connected despite the lysosomal degradation of Tc ( 3 )/Re ( 3 ). These compounds are the first examples of (99m)Tc bioconjugates that combine specific cell targeting with nuclear internalization, a crucial issue to explore use of (99m)Tc in Auger therapy.
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Affiliation(s)
- Teresa Esteves
- Unidade de Ciências Químicas e Radiofarmacêuticas, Instituto Tecnológico e Nuclear, Estrada Nacional, Sacavém, Portugal
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Zelenka K, Borsig L, Alberto R. Metal complex mediated conjugation of peptides to nucleus targeting acridine orange: a modular concept for dual-modality imaging agents. Bioconjug Chem 2011; 22:958-67. [PMID: 21480670 DOI: 10.1021/bc2000269] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To target the nucleus of specific cells, trifunctional radiopharmaceuticals are required. We have synthesized acridine orange derivatives which comprise an imidazole-2-carbaldehyde function for coordination to the [Re(CO)₃](+) or [(99m)Tc(CO)₃](+) core. Upon coordination, this aldehyde is activated and rapidly forms imines with amines from biological molecules. This metal-mediated imine formation allows for the conjugation of a nuclear targeting portion with a specific cell receptor binding function directly on the metal. With this concept, we have conjugated the acridine orange part to a bombesin peptide directly on the (99m)Tc core and in one step. In addition, a linker containing an integrated disulfide has been coupled to bombesin. LC/MS study showed that the disulfide was reductively cleaved with a 60 min half-life time. This concept enables the combination of a nucleus targeting agent with a specific cell receptor molecule directly on the metal without the need of separate conjugation prior to labeling, thus, a modular approach. High uptake of the BBN conjugate into PC-3 cells was detected by fluorescence microscopy, whereas uptake into B16BL6 cells was negligible.
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Affiliation(s)
- Karel Zelenka
- Institute of Inorganic Chemistry, University of Zürich, Winterthurerstrasse 190, Zürich, Switzerland
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