1
|
Rivas C, Jackson JA, Rigby A, Jarvis JA, White AJP, Blower PJ, Phanopoulos A, Ma MT. Probing Unexpected Reactivity in Radiometal Chemistry: Indium-111-Mediated Hydrolysis of Hybrid Cyclen-Hydroxypyridinone Ligands. Inorg Chem 2023; 62:5270-5281. [PMID: 36926900 PMCID: PMC10074387 DOI: 10.1021/acs.inorgchem.3c00353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
Chelators based on hydroxypyridinones have utility in incorporating radioactive metal ions into diagnostic and therapeutic agents used in nuclear medicine. Over the course of our hydroxypyridinone studies, we have prepared two novel chelators, consisting of a cyclen (1,4,7,10-tetraazacyclododecane) ring bearing two pendant hydroxypyridinone groups, appended via methylene acetamide motifs at either the 1,4-positions (L1) or 1,7-positions (L2) of the cyclen ring. In radiolabeling reactions of L1 or L2 with the γ-emitting radioisotope, [111In]In3+, we have observed radiometal-mediated hydrolysis of a single amide group of either L1 or L2. The reaction of either [111In]In3+ or [natIn]In3+ with either L1 or L2, in aqueous alkaline solutions at 80 °C, initially results in formation of [In(L1)]+ or [In(L2)]+, respectively. Over time, each of these species undergoes In3+-mediated hydrolysis of a single amide group to yield species in which In3+ remains coordinated to the resultant chelator, which consists of a cyclen ring bearing a single hydroxypyridinone group and a single carboxylate group. The reactivity toward hydrolysis is higher for the L1 complex compared to that for the L2 complex. Density functional theory calculations corroborate these experimental findings and importantly indicate that the activation energy required for the hydrolysis of L1 is significantly lower than that required for L2. This is the first reported example of a chelator undergoing radiometal-mediated hydrolysis to form a radiometalated complex. It is possible that metal-mediated amide bond cleavage is a source of instability in other radiotracers, particularly those in which radiometal complexation occurs in aqueous, basic solutions at high temperatures. This study highlights the importance of appropriate characterization of radiolabeled products.
Collapse
Affiliation(s)
- Charlotte Rivas
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor Lambeth Wing, St Thomas' Hospital, London SE1 7EH, U.K
| | - Jessica A Jackson
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor Lambeth Wing, St Thomas' Hospital, London SE1 7EH, U.K
| | - Alex Rigby
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor Lambeth Wing, St Thomas' Hospital, London SE1 7EH, U.K
| | - James A Jarvis
- Randall Centre of Cell and Molecular Biophysics and Centre for Biomolecular Spectroscopy, King's College London, London SE1 9RT, U.K
| | - Andrew J P White
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London W12 0BZ, U.K
| | - Philip J Blower
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor Lambeth Wing, St Thomas' Hospital, London SE1 7EH, U.K
| | - Andreas Phanopoulos
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London W12 0BZ, U.K
| | - Michelle T Ma
- School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor Lambeth Wing, St Thomas' Hospital, London SE1 7EH, U.K
| |
Collapse
|
2
|
Aziz OA, Zeller M, Zaleski CM. Crystal structure of an indium–salicylhydroximate complex cation: [In 4(H 2shi) 8(H 2O) 6](NO 3) 4·8.57H 2O. Acta Crystallogr E Crystallogr Commun 2022; 78:926-931. [PMID: 36072520 PMCID: PMC9443793 DOI: 10.1107/s2056989022007964] [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: 07/20/2022] [Accepted: 08/08/2022] [Indexed: 11/23/2022]
Abstract
The title compound [In4(H2shi)8(H2O)6](NO3)4·8.57H2O·solvent, where H2shi− is salicylhydroximate, is a dimer of two [In2(H2shi)4(H2O)3]2+ units that are related by an inversion center. The overall configuration of the dimer has a step-like topology, and each InIII ion is seven coordinate with a pentagonal–bipyramidal geometry. The synthesis and crystal structure for the title compound, hexaaquahexakis(μ-2-hydroxybenzenecarbohydroxamato)bis(2-hydroxybenzenecarbohydroxamato)tetraindium(III) tetranitrate 8.57-hydrate + unknown solvent, [In4(H2shi)8(H2O)6](NO3)4·8.57H2O·solvent, where H2shi− is salicylhydroximate (C7H5NO3), are reported. The complex cation of the structure, [In4(H2shi)8(H2O)6]4+, is a dimer with a step-like topology and possesses an inversion center that relates each [In2(H2shi)4(H2O)3]2+ side of the complex cation. Each InIII ion is seven-coordinate with a pentagonal–bipyramidal geometry, and the salicylhydroximate ligands have a 1− charge as only the oxime oxygen of the ligand is deprotonated. Four interstitial nitrate anions maintain the charge balance of the compound. One of the nitrate anions (and its symmetry equivalent) is disordered over two different orientations with an occupancy ratio of 0.557 (7) to 0.443 (7). The interstitial solvent water molecules show substantial disorder. Approximately 8.57 water molecules per formula unit were refined as disordered and partially occupied, while a suitable model could not be devised for the other extensively disordered solvent molecules (water and possibly methanol as this was the synthesis solvent). Thus, these latter solvent molecules were instead treated with the SQUEEZE routine [Spek (2015). Acta Cryst. C71, 9–18.] as implemented in the program PLATON, and the procedure corrected for 151 electrons within solvent-accessible voids of 367 Å3.
Collapse
|
3
|
Liao Z, Li F, Tang Y, Liu W, Gao J, Lan T, Yang J, Liao J, Liu N, Yang Y. Preliminary in vitro comparison of 111In and 131I labeled nimotuzumabs. J Radioanal Nucl Chem 2021. [DOI: 10.1007/s10967-021-07677-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
|
4
|
Ahn SH, Iuliano JN, Boros E. Trivalent metal complex geometry of the substrate governs cathepsin B enzymatic cleavage rate. Chem Commun (Camb) 2020; 56:7289-7292. [DOI: 10.1039/d0cc02862b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The identity of the trivalent metal ion controls the rate of the enzymatic cleavage of a series of metal-complexed cathepsin B substrates. Increasing the distance between the metal complex and the enzyme cleavage site diminishes this effect.
Collapse
Affiliation(s)
- Shin Hye Ahn
- Department of Chemistry
- Stony Brook University
- 100 Nicolls Rd
- Stony Brook
- New York
| | - James N. Iuliano
- Department of Chemistry
- Stony Brook University
- 100 Nicolls Rd
- Stony Brook
- New York
| | - Eszter Boros
- Department of Chemistry
- Stony Brook University
- 100 Nicolls Rd
- Stony Brook
- New York
| |
Collapse
|
5
|
Abstract
Radiometals possess an exceptional breadth of decay properties and have been applied to medicine with great success for several decades. The majority of current clinical use involves diagnostic procedures, which use either positron-emission tomography (PET) or single-photon imaging to detect anatomic abnormalities that are difficult to visualize using conventional imaging techniques (e.g., MRI and X-ray). The potential of therapeutic radiometals has more recently been realized and relies on ionizing radiation to induce irreversible DNA damage, resulting in cell death. In both cases, radiopharmaceutical development has been largely geared toward the field of oncology; thus, selective tumor targeting is often essential for efficacious drug use. To this end, the rational design of four-component radiopharmaceuticals has become popularized. This Review introduces fundamental concepts of drug design and applications, with particular emphasis on bifunctional chelators (BFCs), which ensure secure consolidation of the radiometal and targeting vector and are integral for optimal drug performance. Also presented are detailed accounts of production, chelation chemistry, and biological use of selected main group and rare earth radiometals.
Collapse
Affiliation(s)
- Thomas I Kostelnik
- Medicinal Inorganic Chemistry Group, Department of Chemistry , University of British Columbia , Vancouver , British Columbia V6T 1Z1 , Canada
| | - Chris Orvig
- Medicinal Inorganic Chemistry Group, Department of Chemistry , University of British Columbia , Vancouver , British Columbia V6T 1Z1 , Canada
| |
Collapse
|
6
|
Comba P, Jermilova U, Orvig C, Patrick BO, Ramogida CF, Rück K, Schneider C, Starke M. Octadentate Picolinic Acid-Based Bispidine Ligand for Radiometal Ions. Chemistry 2017; 23:15945-15956. [DOI: 10.1002/chem.201702284] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Indexed: 11/10/2022]
Affiliation(s)
- Peter Comba
- Universität Heidelberg; Anorganisch-Chemisches Institut and Interdisciplinary Center for Scientific Computing, INF 270, D-; 69120 Heidelberg Germany
| | - Una Jermilova
- Life Sciences Division; TRIUMF; 4004 Wesbrook Mall Vancouver V6T 2A3 British Columbia Canada
| | - Chris Orvig
- Medicinal Inorganic Chemistry Group; University of British Columbia; Department of Chemistry; 2036 Main Mall Vancouver V6T 1Z1 British Columbia Canada
| | - Brian O. Patrick
- Medicinal Inorganic Chemistry Group; University of British Columbia; Department of Chemistry; 2036 Main Mall Vancouver V6T 1Z1 British Columbia Canada
| | - Caterina F. Ramogida
- Life Sciences Division; TRIUMF; 4004 Wesbrook Mall Vancouver V6T 2A3 British Columbia Canada
| | - Katharina Rück
- Universität Heidelberg; Anorganisch-Chemisches Institut and Interdisciplinary Center for Scientific Computing, INF 270, D-; 69120 Heidelberg Germany
| | - Christina Schneider
- Universität Heidelberg; Anorganisch-Chemisches Institut and Interdisciplinary Center for Scientific Computing, INF 270, D-; 69120 Heidelberg Germany
| | - Miriam Starke
- Universität Heidelberg; Anorganisch-Chemisches Institut and Interdisciplinary Center for Scientific Computing, INF 270, D-; 69120 Heidelberg Germany
| |
Collapse
|
7
|
Srivastava S, Fergason-Cantrell EA, Nahas RI, Lever JR. Synthesis and opioid receptor binding of indium (III) and [ 111In]-labeled macrocyclic conjugates of diprenorphine: novel ligands designed for imaging studies of peripheral opioid receptors. Tetrahedron 2016; 72:6127-6135. [PMID: 28190898 DOI: 10.1016/j.tet.2016.08.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Radiolabeled diprenorphine (DPN) and analogs are widely used ligands for non-invasive brain imaging of opioid receptors. To develop complementary radioligands optimized for studies of the peripheral opioid receptors, we prepared a pair of hydrophilic DPN derivatives, conjugated to the macrocyclic chelator DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid), for complexation with trivalent metals. The non-radioactive indium (III) complexes, tethered to the C6-oxygen position of the DPN scaffold by 6- to 9-atom spacers, displayed high affinities for binding to μ, δ and κ opioid receptors in vitro. Use of the 9-atom linker conferred picomolar affinities equipotent to those of the parent ligand DPN. The [111In]-labeled complexes were prepared in good yield (>70%), with high radiochemical purity (~99%) and high specific radioactivity (>4000 mCi/μmol). Their log D7.4 values were -2.21 to -1.66. In comparison, DPN is lipophilic, with a log D7.4 of +2.25. Further study in vivo is warranted to assess the suitability of these [111In]-labeled DPN-DOTA conjugates for imaging trials.
Collapse
Affiliation(s)
- Shefali Srivastava
- Department of Radiology, University of Missouri, Columbia, MO 65211, USA; Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO 65201, USA
| | - Emily A Fergason-Cantrell
- Department of Radiology, University of Missouri, Columbia, MO 65211, USA; Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO 65201, USA
| | - Roger I Nahas
- Department of Chemistry, University of Missouri, Columbia, MO 65212, USA; Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO 65201, USA
| | - John R Lever
- Department of Radiology, University of Missouri, Columbia, MO 65211, USA; Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO 65201, USA
| |
Collapse
|
8
|
Laurent G, Bernhard C, Dufort S, Jiménez Sánchez G, Bazzi R, Boschetti F, Moreau M, Vu TH, Collin B, Oudot A, Herath N, Requardt H, Laurent S, Vander Elst L, Muller R, Dutreix M, Meyer M, Brunotte F, Perriat P, Lux F, Tillement O, Le Duc G, Denat F, Roux S. Minor changes in the macrocyclic ligands but major consequences on the efficiency of gold nanoparticles designed for radiosensitization. NANOSCALE 2016; 8:12054-12065. [PMID: 27244570 DOI: 10.1039/c6nr01228k] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Many studies have been devoted to adapting the design of gold nanoparticles to efficiently exploit their promising capability to enhance the effects of radiotherapy. In particular, the addition of magnetic resonance imaging modality constitutes an attractive strategy for enhancing the selectivity of radiotherapy since it allows the determination of the most suited delay between the injection of nanoparticles and irradiation. This requires the functionalization of the gold core by an organic shell composed of thiolated gadolinium chelates. The risk of nephrogenic systemic fibrosis induced by the release of gadolinium ions should encourage the use of macrocyclic chelators which form highly stable and inert complexes with gadolinium ions. In this context, three types of gold nanoparticles (Au@DTDOTA, Au@TADOTA and Au@TADOTAGA) combining MRI, nuclear imaging and radiosensitization have been developed with different macrocyclic ligands anchored onto the gold cores. Despite similarities in size and organic shell composition, the distribution of gadolinium chelate-coated gold nanoparticles (Au@TADOTA-Gd and Au@TADOTAGA-Gd) in the tumor zone is clearly different. As a result, the intravenous injection of Au@TADOTAGA-Gd prior to the irradiation of 9L gliosarcoma bearing rats leads to the highest increase in lifespan whereas the radiophysical effects of Au@TADOTAGA-Gd and Au@TADOTA-Gd are very similar.
Collapse
Affiliation(s)
- G Laurent
- Institut UTINAM, UMR 6213 CNRS-UBFC, Université de Bourgogne Franche-Comté, 25030 Besançon Cedex, France.
| | - C Bernhard
- Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB), UMR 6302 CNRS-UBFC, Université de Bourgogne Franche-Comté, 21078 Dijon Cedex, France
| | - S Dufort
- Nano-H S.A.S, 2 Place de l'Europe, 38070 Saint Quentin-Fallavier, France
| | - G Jiménez Sánchez
- Institut UTINAM, UMR 6213 CNRS-UBFC, Université de Bourgogne Franche-Comté, 25030 Besançon Cedex, France.
| | - R Bazzi
- Institut UTINAM, UMR 6213 CNRS-UBFC, Université de Bourgogne Franche-Comté, 25030 Besançon Cedex, France.
| | | | - M Moreau
- Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB), UMR 6302 CNRS-UBFC, Université de Bourgogne Franche-Comté, 21078 Dijon Cedex, France
| | - T H Vu
- Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB), UMR 6302 CNRS-UBFC, Université de Bourgogne Franche-Comté, 21078 Dijon Cedex, France
| | - B Collin
- Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB), UMR 6302 CNRS-UBFC, Université de Bourgogne Franche-Comté, 21078 Dijon Cedex, France and Plateforme d'imagerie préclinique, Centre Georges-François Leclerc, 21079 Dijon Cedex, France
| | - A Oudot
- Plateforme d'imagerie préclinique, Centre Georges-François Leclerc, 21079 Dijon Cedex, France
| | - N Herath
- Recombinaison, réparation et cancer: de la molécule au patient, Institut Curie, UMR CNRS 3347 - Inserm U1021, 91405 Orsay, France
| | - H Requardt
- ID17 Biomedical Beamline, European Synchrotron Radiation Facility, 38000 Grenoble, France
| | - S Laurent
- NMR Laboratory, Université de Mons, 7000 Mons, Belgium
| | - L Vander Elst
- NMR Laboratory, Université de Mons, 7000 Mons, Belgium
| | - R Muller
- NMR Laboratory, Université de Mons, 7000 Mons, Belgium
| | - M Dutreix
- Recombinaison, réparation et cancer: de la molécule au patient, Institut Curie, UMR CNRS 3347 - Inserm U1021, 91405 Orsay, France
| | - M Meyer
- Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB), UMR 6302 CNRS-UBFC, Université de Bourgogne Franche-Comté, 21078 Dijon Cedex, France
| | - F Brunotte
- Plateforme d'imagerie préclinique, Centre Georges-François Leclerc, 21079 Dijon Cedex, France
| | - P Perriat
- Matériaux Ingénierie et Science, UMR 5510 CNRS-INSA, INSA de Lyon, 69621 Villeurbanne Cedex, France
| | - F Lux
- Institut Lumière Matière, UMR 5306 CNRS-UCBL, Université de Lyon, 69622 Villeurbanne Cedex, France
| | - O Tillement
- Institut Lumière Matière, UMR 5306 CNRS-UCBL, Université de Lyon, 69622 Villeurbanne Cedex, France
| | - G Le Duc
- ID17 Biomedical Beamline, European Synchrotron Radiation Facility, 38000 Grenoble, France
| | - F Denat
- Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB), UMR 6302 CNRS-UBFC, Université de Bourgogne Franche-Comté, 21078 Dijon Cedex, France
| | - S Roux
- Institut UTINAM, UMR 6213 CNRS-UBFC, Université de Bourgogne Franche-Comté, 25030 Besançon Cedex, France.
| |
Collapse
|
9
|
Kriemen E, Holzapfel M, Ruf E, Rehbein J, Maison W. Synthesis and Structural Analysis of 1,4,7,10-Tetraazacyclododecane-1,4,7,10-tetraazidoethylacetic Acid (DOTAZA) Complexes. Eur J Inorg Chem 2015. [DOI: 10.1002/ejic.201500789] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
10
|
Price EW, Zeglis BM, Cawthray JF, Lewis JS, Adam MJ, Orvig C. What a difference a carbon makes: H₄octapa vs H₄C3octapa, ligands for In-111 and Lu-177 radiochemistry. Inorg Chem 2014; 53:10412-31. [PMID: 25192223 PMCID: PMC4186671 DOI: 10.1021/ic501466z] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
![]()
The acyclic ligands H4C3octapa and p-SCN-Bn-H4C3octapa were
synthesized for the first time,
using nosyl protection chemistry. These new ligands were compared
to the previously studied ligands H4octapa and p-SCN-Bn-H4octapa to determine the extent to
which the addition of a single carbon atom to the backbone of the
ligand would affect metal coordination, complex stability, and, ultimately,
utility for in vivo radiopharmaceutical applications. Although only
a single carbon atom was added to H4C3octapa and the metal
donor atoms and denticity were not changed, the solution chemistry
and radiochemistry properties were drastically altered, highlighting
the importance of careful ligand design and radiometal–ligand
matching. It was found that [In(C3octapa)]− and
[Lu(C3octapa)]− were substantially different from
the analogous H4octapa complexes, exhibiting fluxional
isomerization and a higher number of isomers, as observed by 1H NMR, VT-NMR, and 2D COSY/HSQC-NMR experiments. Past evaluation
of the DFT structures of [In(octapa)]− and [Lu(octapa)]− revealed very symmetric complexes; in contrast, the
[In(C3octapa)]− and [Lu(C3octapa)]− complexes were much less symmetric, suggesting lower symmetry and
less rigidity than that of the analogous H4octapa complexes.
Potentiometric titrations revealed the formation constants (log KML, pM) were ∼2 units lower for the In3+ and Lu3+ complexes of H4C3octapa when
compared to that of the more favorable H4octapa ligand
(∼2 orders of magnitude less thermodynamically stable). The
bifunctional ligands p-SCN-Bn-H4C3octapa
and p-SCN-Bn-H4octapa were conjugated
to the antibody trastuzumab and radiolabeled with 111In
and 177Lu. Over a 5 day stability challenge experiment
in blood serum, 111In-octapa– and 111In-C3octapa–trastuzumab immunoconjugates were determined to
be ∼91 and ∼24% stable, respectively, and 177Lu-octapa– and 177Lu-C3octapa–trastuzumab,
∼89% and ∼4% stable, respectively. This work suggests
that 5-membered chelate rings are superior to 6-membered chelate rings
for large metal ions like In3+ and Lu3+, which
is a crucial consideration for the design of bifunctional chelates
for bioconjugation to targeting vectors for in vivo work. New ligands H4C3octapa and p-SCN-Bn-H4C3octapa
were synthesized and compared to the previously studied ligands H4octapa and p-SCN-Bn-H4octapa to
determine the extent to which the addition of a single carbon atom
to the backbone of the ligand would affect metal coordination, complex
stability, and, ultimately, utility for in vivo radiopharmaceutical
applications. It was found that [In(C3octapa)]− and
[Lu(C3octapa)]− were substantially different from
the analogous H4octapa complexes.
Collapse
Affiliation(s)
- Eric W Price
- Medicinal Inorganic Chemistry Group, Department of Chemistry, University of British Columbia , 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | | | | | | | | | | |
Collapse
|
11
|
Price EW, Ferreira CL, Adam MJ, Orvig C. High-denticity ligands based on picolinic acid for 111In radiochemistry. CAN J CHEM 2014. [DOI: 10.1139/cjc-2013-0542] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Four new acyclic ligands, Bn-H3nonapa (3), H3nonapa (4), p-NO2-Bn-H3nonapa (10), and Bn-H3trenpa (7), were synthesized and studied with nonradioactive In3+ and with radioactive 111In3+. The coordination of these ligands to In3+ was confirmed by high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy. Radiolabeling experiments were performed with 111In3+; these demonstrated H3nonapa (4) to be the best indium ligand of those studied herein, achieving radiochemical yields of ∼97% in 10 min at ambient temperature, and stability to transchelation in mouse serum of 44.5% ± 25.9% after 24 h. Although the radiolabeling kinetics of H3nonapa (4) were excellent, serum stability results were inferior to the previously studied ligands DOTA, DTPA, and H4octapa, suggesting that the presented ligands may find their optimum radiopharmaceutical applications with isotopes other than 111In. Owing to the high denticity of these ligands (9–10 coordinate), they may realize their potential with large ion isotopes such as 177Lu, 86/90Y, and 225Ac.
Collapse
Affiliation(s)
- Eric W. Price
- Medicinal Inorganic Chemistry Group, Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3, Canada
| | | | | | - Chris Orvig
- Medicinal Inorganic Chemistry Group, Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| |
Collapse
|
12
|
Abstract
Radiometals comprise many useful radioactive isotopes of various metallic elements. When properly harnessed, these have valuable emission properties that can be used for diagnostic imaging techniques, such as single photon emission computed tomography (SPECT, e.g.(67)Ga, (99m)Tc, (111)In, (177)Lu) and positron emission tomography (PET, e.g.(68)Ga, (64)Cu, (44)Sc, (86)Y, (89)Zr), as well as therapeutic applications (e.g.(47)Sc, (114m)In, (177)Lu, (90)Y, (212/213)Bi, (212)Pb, (225)Ac, (186/188)Re). A fundamental critical component of a radiometal-based radiopharmaceutical is the chelator, the ligand system that binds the radiometal ion in a tight stable coordination complex so that it can be properly directed to a desirable molecular target in vivo. This article is a guide for selecting the optimal match between chelator and radiometal for use in these systems. The article briefly introduces a selection of relevant and high impact radiometals, and their potential utility to the fields of radiochemistry, nuclear medicine, and molecular imaging. A description of radiometal-based radiopharmaceuticals is provided, and several key design considerations are discussed. The experimental methods by which chelators are assessed for their suitability with a variety of radiometal ions is explained, and a large selection of the most common and most promising chelators are evaluated and discussed for their potential use with a variety of radiometals. Comprehensive tables have been assembled to provide a convenient and accessible overview of the field of radiometal chelating agents.
Collapse
Affiliation(s)
- Eric W Price
- Medicinal Inorganic Chemistry Group, Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, CanadaV6T 1Z1.
| | | |
Collapse
|
13
|
Bailey GA, Price EW, Zeglis BM, Ferreira CL, Boros E, Lacasse MJ, Patrick BO, Lewis JS, Adam MJ, Orvig C. H(2)azapa: a versatile acyclic multifunctional chelator for (67)Ga, (64)Cu, (111)In, and (177)Lu. Inorg Chem 2012; 51:12575-89. [PMID: 23106422 DOI: 10.1021/ic302225z] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Preliminary experiments with the novel acyclic triazole-containing bifunctional chelator H2azapa and the radiometals (64)Cu, (67)Ga, (111)In, and (177)Lu have established its significant versatile potential as an alternative to 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) for metal-based radiopharmaceuticals. Unlike DOTA, H2azapa radiolabels quantitatively with (64)Cu, (67)Ga, (111)In, and (177)Lu in 10 min at room temperature. In vitro competition experiments with human blood serum show that (64)Cu remained predominantly chelate-bound, with only 2% transchelated to serum proteins after 20 h. Biodistribution experiments with [(64)Cu(azapa)] in mice reveal uptake in various organs, particularly in the liver, lungs, heart, intestines, and kidneys. When compared to [(64)Cu(DOTA)](2-), the lipophilic neutral [(64)Cu(azapa)] was cleared through the gastrointestinal tract and accumulated in the liver, which is common for lipophilic compounds or free (64)Cu. The chelator H2azapa is a model complex for a click-based bifunctional chelating agent, and the lipophilic benzyl "place-holders" will be replaced by hydrophilic peptides to modulate the pharmacokinetics and direct activity away from the liver and gut. The solid-state molecular structure of [In(azapa)(H2O)][ClO4] reveals a very rare eight-coordinate distorted square antiprismatic geometry with one triazole arm bound, and the structure of [(64)Cu(azapa)] shows a distorted octahedral geometry. The present study demonstrates significant potential for bioconjugates of H2azapa as alternatives to DOTA in copper-based radiopharmaceuticals, with the highly modular and "clickable" molecular scaffold of H2azapa easily modified into a variety of bioconjugates. H2azapa is a versatile addition to the "pa" family, joining the previously published H2dedpa ((67/68)Ga and (64)Cu), H4octapa ((111)In, (177)Lu, and (90)Y), and H5decapa ((225)Ac) to cover a wide range of important nuclides.
Collapse
Affiliation(s)
- Gwendolyn A Bailey
- Medicinal Inorganic Chemistry Group, Department of Chemistry, University of British Columbia , 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Synthesis and evaluation of 111In-labeled d-glucose as a potential SPECT imaging agent. J Radioanal Nucl Chem 2012. [DOI: 10.1007/s10967-012-2224-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
15
|
Moreau M, Raguin O, Vrigneaud JM, Collin B, Bernhard C, Tizon X, Boschetti F, Duchamp O, Brunotte F, Denat F. DOTAGA-trastuzumab. A new antibody conjugate targeting HER2/Neu antigen for diagnostic purposes. Bioconjug Chem 2012; 23:1181-8. [PMID: 22519915 DOI: 10.1021/bc200680x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Improved bifunctional chelating agents (BFC) are required for indium-111 radiolabeling of monoclonal antibodies (mAbs) under mild conditions to yield stable, target-specific agents. 2,2',2"-(10-(2,6-Dioxotetrahydro-2H-pyran-3-yl)-1,4,7,10-tetraazacyclododecane-1,4,7-triyl)triacetic acid (DOTAGA-anhydride) was evaluated for mAb conjugation and labeling with indium-111. The DOTA analogue was synthesized and conjugated to trastuzumab-which targets the HER2/neu receptor-in mild conditions (PBS pH 7.4, 25 °C, 30 min) and gave a mean degree of conjugation of 2.6 macrocycle per antibody. Labeling of this immunoconjugate with indium-111 was performed in 75% yield after 1 h at 37 °C, and the proportion of (111)In-DOTAGA-trastuzumab reached 97% after purification. The affinity of DOTAGA-trastuzumab was 5.5 ± 0.6 nM as evaluated by in vitro saturation assays using HCC1954 breast cancer cell line. SPECT/CT imaging and biodistribution studies were performed in mice bearing breast cancer BT-474 xenografts. BT-474 tumors were clearly visualized on SPECT images at 24, 48, and 72 h postinjection. The tumor uptake of [(111)In-DOTAGA]-trastuzumab reached 65%ID/g 72 h postinjection. These results show that the DOTAGA BFC appears to be a valuable tool for biologics conjugation.
Collapse
Affiliation(s)
- Mathieu Moreau
- Institut de Chimie Moléculaire de l'Université de Bourgogne , UMR CNRS 6302, 21078 Dijon Cedex, France
| | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Liu G, Li Y, Sheth VR, Pagel MD. Imaging in Vivo Extracellular pH with a Single Paramagnetic Chemical Exchange Saturation Transfer Magnetic Resonance Imaging Contrast Agent. Mol Imaging 2012. [DOI: 10.2310/7290.2011.00026] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Guanshu Liu
- From the F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD; Department of Radiology, Johns Hopkins University, Baltimore, MD; Departments of Radiology and Biomedical Engineering, Case Western Reserve University, Cleveland, OH; Departments of Biomedical Engineering and Chemistry and Biochemistry, University of Arizona, Tucson, AZ; and Arizona Cancer Center, Tucson, AZ
| | - Yuguo Li
- From the F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD; Department of Radiology, Johns Hopkins University, Baltimore, MD; Departments of Radiology and Biomedical Engineering, Case Western Reserve University, Cleveland, OH; Departments of Biomedical Engineering and Chemistry and Biochemistry, University of Arizona, Tucson, AZ; and Arizona Cancer Center, Tucson, AZ
| | - Vipul R. Sheth
- From the F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD; Department of Radiology, Johns Hopkins University, Baltimore, MD; Departments of Radiology and Biomedical Engineering, Case Western Reserve University, Cleveland, OH; Departments of Biomedical Engineering and Chemistry and Biochemistry, University of Arizona, Tucson, AZ; and Arizona Cancer Center, Tucson, AZ
| | - Mark D. Pagel
- From the F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD; Department of Radiology, Johns Hopkins University, Baltimore, MD; Departments of Radiology and Biomedical Engineering, Case Western Reserve University, Cleveland, OH; Departments of Biomedical Engineering and Chemistry and Biochemistry, University of Arizona, Tucson, AZ; and Arizona Cancer Center, Tucson, AZ
| |
Collapse
|
17
|
|
18
|
Demmer O, Dijkgraaf I, Schumacher U, Marinelli L, Cosconati S, Gourni E, Wester HJ, Kessler H. Design, synthesis, and functionalization of dimeric peptides targeting chemokine receptor CXCR4. J Med Chem 2011; 54:7648-62. [PMID: 21905730 DOI: 10.1021/jm2009716] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The chemokine receptor CXCR4 is a critical regulator of inflammation and immune surveillance, and it is specifically implicated in cancer metastasis and HIV-1 infection. On the basis of the observation that several of the known antagonists remarkably share a C(2) symmetry element, we constructed symmetric dimers with excellent antagonistic activity using a derivative of a cyclic pentapeptide as monomer. To optimize the binding affinity, we investigated the influence of the distance between the monomers and the pharmacophoric sites in the synthesized constructs. The affinity studies in combination with docking computations support a two-site binding model. In a final step, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) was introduced as chelator for (radio-)metals, thus allowing to exploit these compounds as a new group of CXCR4-binding peptidic probes for molecular imaging and endoradiotherapeutic purposes. Both the DOTA conjugates and some of their corresponding metal complexes retain good CXCR4 affinity, and one (68)Ga labeled compound was studied as PET tracer.
Collapse
Affiliation(s)
- Oliver Demmer
- Institute for Advanced Study, Technische Universität München , Lichtenbergstrasse 4, D-85748 Garching, Germany
| | | | | | | | | | | | | | | |
Collapse
|
19
|
Orcutt KD, Slusarczyk AL, Cieslewicz M, Ruiz-Yi B, Bhushan KR, Frangioni JV, Wittrup KD. Engineering an antibody with picomolar affinity to DOTA chelates of multiple radionuclides for pretargeted radioimmunotherapy and imaging. Nucl Med Biol 2010; 38:223-33. [PMID: 21315278 DOI: 10.1016/j.nucmedbio.2010.08.013] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2009] [Revised: 08/04/2010] [Accepted: 08/31/2010] [Indexed: 11/28/2022]
Abstract
INTRODUCTION In pretargeted radioimmunotherapy (PRIT), a bifunctional antibody is administered and allowed to pre-localize to tumor cells. Subsequently, a chelated radionuclide is administered and captured by cell-bound antibody while unbound hapten clears rapidly from the body. We aim to engineer high-affinity binders to 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelates for use in PRIT applications. METHODS We mathematically modeled antibody and hapten pharmacokinetics to analyze hapten tumor retention as a function of hapten binding affinity. Motivated by model predictions, we used directed evolution and yeast surface display to affinity mature the 2D12.5 antibody to DOTA, reformatted as a single chain variable fragment (scFv). RESULTS Modeling predicts that for high antigen density and saturating bsAb dose, a hapten-binding affinity of 100 pM is needed for near-maximal hapten retention. We affinity matured 2D12.5 with an initial binding constant of about 10 nM to DOTA-yttrium chelates. Affinity maturation resulted in a 1000-fold affinity improvement to biotinylated DOTA-yttrium, yielding an 8.2±1.9 picomolar binder. The high-affinity scFv binds DOTA complexes of lutetium and gadolinium with similar picomolar affinity and indium chelates with low nanomolar affinity. When engineered into a bispecific antibody construct targeting carcinoembryonic antigen, pretargeted high-affinity scFv results in significantly higher tumor retention of a (111)In-DOTA hapten compared to pretargeted wild-type scFv in a xenograft mouse model. CONCLUSIONS We have engineered a versatile, high-affinity, DOTA-chelate-binding scFv. We anticipate it will prove useful in developing pretargeted imaging and therapy protocols to exploit the potential of a variety of radiometals.
Collapse
Affiliation(s)
- Kelly Davis Orcutt
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | | | | | | | | | | |
Collapse
|
20
|
Saludes JP, Natarajan A, DeNardo SJ, Gervay-Hague J. The remarkable stability of chimeric, sialic acid-derived alpha/delta-peptides in human blood plasma. Chem Biol Drug Des 2010; 75:455-60. [PMID: 20486931 DOI: 10.1111/j.1747-0285.2010.00954.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Peptides are labile toward proteolytic enzymes, and structural modifications are often required to prolong their metabolic half-life and increase resistance. One modification is the incorporation of non-alpha-amino acids into the peptide to deter recognition by hydrolytic enzymes. We previously reported the synthesis of chimeric alpha/delta-peptides from glutamic acids (Glu) and the sialic acid derivative Neu2en. Conformational analyses revealed these constructs adopt secondary structures in water and may serve as conformational surrogates of polysialic acid. Polysialic acid is a tumor-associated polysaccharide and is correlated with cancer metastasis. Soluble polysialic acid is rapidly cleared from the blood limiting its potential for vaccine development. One motivation in developing structural surrogates of polysialic acid was to create constructs with increased bioavailability. Here, we report plasma stability profiles of Glu/Neu2en alpha/delta-peptides. DOTA was conjugated at the peptide N-termini by solid phase peptide synthesis, radiolabeled with (111)In, incubated in human blood plasma at 37 degrees C, and their degradation patterns monitored by cellulose acetate electrophoresis and radioactivity counting. Results indicate that these peptides exhibit a long half-life that is two- to three-orders of magnitude higher than natural alpha-peptides. These findings provide a viable platform for the synthesis of plasma stable, sialic acid-derived peptides that may find pharmaceutical application.
Collapse
Affiliation(s)
- Jonel P Saludes
- Department of Chemistry, University of California, Davis, 95616, USA
| | | | | | | |
Collapse
|
21
|
Wadas TJ, Wong EH, Weisman GR, Anderson CJ. Coordinating radiometals of copper, gallium, indium, yttrium, and zirconium for PET and SPECT imaging of disease. Chem Rev 2010; 110:2858-902. [PMID: 20415480 PMCID: PMC2874951 DOI: 10.1021/cr900325h] [Citation(s) in RCA: 671] [Impact Index Per Article: 47.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Thaddeus J Wadas
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S. Kingshighway Blvd., Campus Box 8225 St. Louis, Missouri 63110, USA.
| | | | | | | |
Collapse
|
22
|
Hamplová A, Křížek T, Kubíček V, Bosáková Z, Coufal P. Comparison of HPLC and CZE methods for analysis of DOTA-like esters - reaction intermediates in synthesis of magnetic resonance contrast agents. J Sep Sci 2010; 33:658-63. [DOI: 10.1002/jssc.200900700] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
23
|
Design, synthesis and in vitro characterization of Glucagon-Like Peptide-1 derivatives for pancreatic beta cell imaging by SPECT. Bioorg Med Chem 2009; 18:1265-72. [PMID: 20056547 DOI: 10.1016/j.bmc.2009.12.032] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2009] [Revised: 12/07/2009] [Accepted: 12/09/2009] [Indexed: 12/25/2022]
Abstract
Novel Glucagon-Like Peptide-1 (GLP-1) derivatives containing the metal chelator DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) and naturally occurring Indium ((113/115)In) were prepared using solid-phase Fmoc methods. All synthesized peptides contained d-Ala-8, a modification known to improve resistance towards degradation by dipeptidyl peptidase-IV. The effect of increased distance between DOTA and the peptide chain was investigated using an (aminoethyl) ethoxy acetyl linker, in order to reduce steric effects imposed by DOTA. Placement of linker and DOTA moieties were also varied within the GLP-1 sequence to test for optimal metal-complex location. The binding affinity of the peptide derivatives was determined in vitro with Chinese hamster ovary cells stably transfected with a human GLP-1 receptor (CHO/GLP-1R) cell line and was shown to be in the nM range. Gamma camera imaging of an insulinoma cell line was carried out using (111)In-labeled peptides. Our results suggest that the prepared GLP-1 derivatives are suitable imaging probes for studying pancreatic islet function in vivo.
Collapse
|
24
|
Liu S. Bifunctional coupling agents for radiolabeling of biomolecules and target-specific delivery of metallic radionuclides. Adv Drug Deliv Rev 2008; 60:1347-70. [PMID: 18538888 PMCID: PMC2539110 DOI: 10.1016/j.addr.2008.04.006] [Citation(s) in RCA: 299] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2007] [Accepted: 04/16/2008] [Indexed: 11/23/2022]
Abstract
Receptor-based radiopharmaceuticals are of great current interest in molecular imaging and radiotherapy of cancers, and provide a unique tool for target-specific delivery of radionuclides to the diseased tissues. In general, a target-specific radiopharmaceutical can be divided into four parts: targeting biomolecule (BM), pharmacokinetic modifying (PKM) linker, bifunctional coupling or chelating agent (BFC), and radionuclide. The targeting biomolecule serves as a "carrier" for specific delivery of the radionuclide. PKM linkers are used to modify radiotracer excretion kinetics. BFC is needed for radiolabeling of biomolecules with a metallic radionuclide. Different radiometals have significant difference in their coordination chemistry, and require BFCs with different donor atoms and chelator frameworks. Since the radiometal chelate can have a significant impact on physical and biological properties of the target-specific radiopharmaceutical, its excretion kinetics can be altered by modifying the coordination environment with various chelators or coligand, if needed. This review will focus on the design of BFCs and their coordination chemistry with technetium, copper, gallium, indium, yttrium and lanthanide radiometals.
Collapse
Affiliation(s)
- Shuang Liu
- School of Health Sciences, Purdue University, West Lafayette, USA.
| |
Collapse
|
25
|
De León-Rodríguez LM, Kovacs Z. The Synthesis and Chelation Chemistry of DOTA−Peptide Conjugates. Bioconjug Chem 2007; 19:391-402. [DOI: 10.1021/bc700328s] [Citation(s) in RCA: 202] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Luis M. De León-Rodríguez
- University of Texas Southwestern Medical Center, Advanced Imaging Research Center, 2201 Inwood Road NE 4.2, Dallas, Texas 75390-8568
| | - Zoltan Kovacs
- University of Texas Southwestern Medical Center, Advanced Imaging Research Center, 2201 Inwood Road NE 4.2, Dallas, Texas 75390-8568
| |
Collapse
|
26
|
In vivo imaging of mucosal CD4+ T cells using single photon emission computed tomography in a murine model of colitis. J Immunol Methods 2007; 329:21-30. [PMID: 17964595 DOI: 10.1016/j.jim.2007.09.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Accepted: 09/19/2007] [Indexed: 01/08/2023]
Abstract
Immune responses that occur in the context of human infectious and inflammatory diseases are usually studied by sampling cells from peripheral blood, from biopsies, or by end-point harvests at necropsy. These approaches are likely to yield information that is incomplete and/or non-representative. Here, we report the development and validation of a non-invasive method to localize and to quantitate the disposition of specific subpopulations of cells in vivo. In a murine model of dextran sulfate sodium (DSS)-induced colitis, CD4+ T cells were visualized in the colon by single photon emission computed tomography (SPECT-CT) after injection of monoclonal, non-depleting, indium-111 (111In) labeled anti-CD4+ antibodies. The SPECT-CT colon uptake ratio (CUR) was found to correlate (p<0.01) with the number of total CD4+ T cells and with standard measures of pathology (colon length, cell counts, and histopathologic evidence of apoptosis, edema, and cellular infiltrates) as assessed by direct examination of diseased colon. Each of these parameters, including the SPECT-CT signal uptake, increased as a function of DSS dose (p<0.05). We conclude that CT-SPECT imaging using an 111In-labeled anti-CD4+ antibody is reflective of traditional parameters of pathology in this experimental model of murine colitis. This approach should be readily applicable to the imaging of discrete cell subpopulations in non-human primates and in humans, thus augmenting our understanding of infectious diseases and inflammation in vivo.
Collapse
|
27
|
Al-Ejeh F, Darby JM, Pensa K, Diener KR, Hayball JD, Brown MP. In vivo targeting of dead tumor cells in a murine tumor model using a monoclonal antibody specific for the La autoantigen. Clin Cancer Res 2007; 13:5519s-5527s. [PMID: 17875784 DOI: 10.1158/1078-0432.ccr-07-0964] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE To investigate the potential of the La-specific monoclonal antibody (mAb) 3B9 as an in vivo tumor-targeting agent. EXPERIMENTAL DESIGN The murine EL4 lymphoma cell line was used for in vitro studies and the EL4 model in which apoptosis was induced with cyclophosphamide and etoposide was used for in vivo studies. In vitro studies compared 3B9 binding in the EL4 cell with that in its counterpart primary cell type of the thymocyte. For in vivo studies, 3B9 was intrinsically or extrinsically labeled with carbon-14 or 1,4,7,10-tetra-azacylododecane-N,N',N'',N''''-tetraacetic acid-indium-111, respectively, and biodistribution of the radiotracers was investigated in EL4 tumor-bearing mice, which were treated or not with chemotherapy. RESULTS La-specific 3B9 mAb bound EL4 cells rather than thymocytes, and binding was detergent resistant. 3B9 binding to dead EL4 cells in vitro was specific, rapid, and saturable. Significantly, more 3B9 bound dead EL4 tumor explant cells after host mice were treated with chemotherapy, which suggested that DNA damage induced 3B9 binding. Tumor binding of 3B9 in vivo was antigen specific and increased significantly after chemotherapy. Tumor accumulation of 3B9 peaked at approximately 50% of the injected dose per gram of tumor 72 h after chemotherapy and correlated with increased tumor cell death. Tumor/organ ratios of 3B9 biodistribution, which included the tumor/blood ratio, exceeded unity 48 or more hours after chemotherapy. CONCLUSIONS La-specific mAb selectively targeted dead tumor cells in vivo, and targeting was augmented by cytotoxic chemotherapy. This novel cell death radioligand may be useful both for radioimmunoscintigraphy and radioimmunotherapy.
Collapse
Affiliation(s)
- Fares Al-Ejeh
- Experimental Therapeutics Laboratory, Hanson Institute, School of Pharmacy and Medical Sciences, University of South Australia, and Department of Medical Oncology, Royal Adelaide Hospital, Australia
| | | | | | | | | | | |
Collapse
|
28
|
Yang CT, Li Y, Liu S. Synthesis and structural characterization of complexes of a DO3A-conjugated triphenylphosphonium cation with diagnostically important metal ions. Inorg Chem 2007; 46:8988-97. [PMID: 17784751 PMCID: PMC2529167 DOI: 10.1021/ic7010452] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
To understand the coordination chemistry of a DO3A-conjugated triphenylphosphonium (TPP) cation, triphenyl(4-((4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododecan-1-yl)methyl)benzyl)phosphonium (DO3A-xy-TPP), with diagnostically important metal ions, In(DO3A-xy-TPP)+, Ga(DO3A-xy-TPP)+, and Mn(DO3A-xy-TPP) were prepared by reacting DO3A-xy-TPP with 1 equiv of the respective metal salt. All three complexes have been characterized by elemental analysis, IR, ESI-MS, NMR methods (for In(DO3A-xy-TPP)+ and Ga(DO3A-xy-TPP)+), and X-ray crystallography. Results from HPLC concordance experiments show that (111)In(DO3A-xy-TPP)+ and In(DO3A-xy-TPP)+ have the same composition. The solid-state structures of In(DO3A-xy-TPP)+ and Mn(DO3A-xy-TPP) are very similar with DO3A being heptadentate in bonding to In(III) and Mn(II) in a monocapped octahedral coordination geometry. Because of the smaller size of Ga(III), the DO3A in Ga(DO3A-xy-TPP)+ is only hexadentate with four amine-N and two carboxylate-O atoms bonding to Ga(III). One carboxylic acid group in DO3A is deprotonated to balance the positive charge of Ga(III). The coordination geometry of Ga(DO3A-xy-TPP)+ is best described as a distorted octahedron. The NMR data shows that the coordinated DO3A in In(DO3A-xy-TPP)+ and Ga(DO3A-xy-TPP)+ is symmetrical in aqueous solution. There is no dissociation of the acetate chelating arms in In(DO3A-xy-TPP)+ and Ga(DO3A-xy-TPP)+, providing indirect evidence for the high solution stability of (111)In(DO3A-xy-TPP)+ and (68)Ga(DO3A-xy-TPP)+.
Collapse
Affiliation(s)
- Chang-Tong Yang
- School of Health Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Yongxin Li
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore
| | - Shuang Liu
- School of Health Sciences, Purdue University, West Lafayette, Indiana, USA
- To whom correspondence should be addressed. School of Health Sciences, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47907. Phone: 765-494-0236; Fax 765-496-1377;
| |
Collapse
|
29
|
Raitsimring AM, Astashkin AV, Baute D, Goldfarb D, Poluektov OG, Lowe MP, Zech SG, Caravan P. Determination of the hydration number of gadolinium(III) complexes by high-field pulsed 17O ENDOR spectroscopy. Chemphyschem 2007; 7:1590-7. [PMID: 16810729 DOI: 10.1002/cphc.200600138] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Pulsed 17O Mims electron-nuclear double resonance (ENDOR) spectroscopy at the W band (95 GHz) and D band (130 GHz) is used for the direct determination of the water coordination number (q) of gadolinium-based magnetic resonance imaging (MRI) contrast agents. Spectra of metal complexes in frozen aqueous solutions at approximately physiological concentrations can be obtained either in the presence or absence of protein targets. This method is an improvement over the 1H ENDOR method described previously, which involved the difference ENDOR spectrum of exchangeable protons from spectra taken in H2O and D2O. In addition to exchangeable water protons, the 1H ENDOR method is also sensitive to other exchangeable protons, and it is shown here that this method can overestimate hydration numbers for complexes with exchangeable protons at GdH distances similar to that of the coordinated water, for example, from NH groups. The 17O method does not suffer from this limitation. 17O ENDOR spectroscopy is applied to Gd(III) complexes containing zero, one, or two inner-sphere water molecules. In addition, 13C and 1H ENDOR studies were performed to assess the extent of methanol coordination, since methanol is used to produce a glass in these experiments. Under the experimental conditions used for the hydration number determination (30 mol % methanol), fewer than 15 % of the coordination sites were found to be occupied by methanol.
Collapse
|
30
|
Schmid M, Neumaier B, Vogg ATJ, Wczasek K, Friesen C, Mottaghy FM, Buck AK, Reske SN. Synthesis and evaluation of a radiometal-labeled macrocyclic chelator-derivatised thymidine analog. Nucl Med Biol 2006; 33:359-66. [PMID: 16631084 DOI: 10.1016/j.nucmedbio.2005.12.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2005] [Revised: 11/23/2005] [Accepted: 12/04/2005] [Indexed: 01/26/2023]
Abstract
Several radiolabeled thymidine analogs as metabolic probes of cell proliferation were developed specifically addressing DNA synthesis. Thymidine analogs containing carboranylalkyl groups for neutron capture therapy at the N-3 position were found to be good substrates for cytosolic thymidine kinase 1 (TK1). According to this approach, a DO3A macrocycle in N-3 position was attached to thymidine. The 3-DO3A thymidine analog was labeled with 68Ga and 111In. Different lipophilicities of the corresponding radiometal-thymidines were detected via RP-HPLC. [111In]DO3A-thymidine ([111In]D3T) was evaluated for cellular uptake in different cell lines (HL60 and DoHH2). Cellular uptake was low in both cell lines. Phosphorylation of the radioconjugates by TK1 was negligible. Although stable complexation of radiometals to thymidine was obtained, introduction of the macrocycle DO3A reduced the affinity to cytosolic TK1 drastically. Low cellular uptake can be ascribed to missing substrate specificity of [111In]DO3A-thymidine for TK1. The absence of substrate specificity may be due to the bulky macrocyclic chelator and partial charges remaining on the coordination sphere due to a more complex solution structure.
Collapse
Affiliation(s)
- Michaela Schmid
- Department of Nuclear Medicine, University Hospital Ulm, 89081 Ulm, Germany
| | | | | | | | | | | | | | | |
Collapse
|
31
|
Shinoda S, Okazaki T, Player TN, Misaki H, Hori K, Tsukube H. Cholesterol-Armed Cyclens for Helical Metal Complexes Offering Chiral Self-Aggregation and Sensing of Amino Acid Anions in Aqueous Solutions. J Org Chem 2005; 70:1835-43. [PMID: 15730308 DOI: 10.1021/jo0478297] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cholesterol-armed cyclens worked as octadentate receptors for Na+, Ca2+, and Y3+ complexes in which four chiral cholesterol-functionalized sidearms were bundled and asymmetrically twisted above cyclen-metal complex platforms. Since the resulting helical metal complexes included chiral, hydrophobic cholesterol residues and charged, hydrophilic metal sites as well as asymmetric coordination geometries, they exhibited unique amphiphilic properties and provided chiral self-aggregates in aqueous solutions. Light scattering, fluorescence, and TEM characterizations demonstrated that Na+ complex with cholesterol-armed cyclen gave a particularly stable self-aggregate in aqueous solution and offered supramolecular environments effective for sensing and detection of amino acid anions. Various dansylamino acid derivatives (dansyl = 5-(dimethylamino)-1-naphthalenesulfonyl) were nicely accommodated in the helicate aggregates to give highly enhanced fluorescence signals, which could be detected by the naked eye at 10(-7) mol/L level. Their inclusion behaviors were analyzed by a Langmuir-type equation, indicating that enantiomer-selective inclusion occurred. MM/MD calculations and circular dichroism (CD) studies further suggested that cholesterol-armed cyclen helicates have chiral and hydrophobic cavities upon self-aggregation, in which the dansylamino acid anions were specifically accommodated. Since these helicates exhibited nonselective binding abilities in solvent extraction experiments of dansylamino acid anions, uncommon chiral recognition and sensing functions were generated by supramolecular alignments of the chiral metal helicates in the aqueous solutions.
Collapse
Affiliation(s)
- Satoshi Shinoda
- Department of Chemistry, Graduate School of Science, Osaka City University, Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | | | | | | | | | | |
Collapse
|
32
|
Hsieh WY, Liu S. Synthesis, Characterization, and Structures of Indium In(DTPA-BA2) and Yttrium Y(DTPA-BA2)(CH3OH) Complexes (BA = Benzylamine): Models for111In- and90Y-Labeled DTPA-Biomolecule Conjugates. Inorg Chem 2004; 43:6006-14. [PMID: 15360250 DOI: 10.1021/ic049973g] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
To explore structural differences in In3+, Y3+, and Lu3+ chelates, we prepared M(DTPA-BA2) complexes (M = In, Y, and Lu; DTPA-BA2 = N,N' '-bis(benzylcarbamoylmethyl)diethylenetriamine-N,N',N' '-triacetic acid) by reacting the trisodium salt of DTPA-BA2 with 1 equiv of metal chloride or nitrate. All three complexes have been characterized by elemental analysis, HPLC, IR, ES-MS, and NMR (1H and 13C) methods. ES-MS spectral and elemental analysis data are consistent with the proposed formula for M(DTPA-BA2) (M = In, Y, and Lu) and have been confirmed by the X-ray crystal structures of both In(DTPA-BA2) x 2H2O and Y(DTPA-BA2)(CH3OH) complexes. By a reversed-phase HPLC method, it was found that In(DTPA-BA2) is more hydrophilic than M(DTPA-BA2) (M = Y and Lu), most likely due to the dissociation of the two carbonyl oxygen donors in solution. The X-ray crystal structure of In(DTPA-BA2) revealed a rare example of an eight-coordinated In3+ complex with DTPA-BA2 bonding to the In3+ in a distorted square antiprism coordination geometry. Both benzylamine groups are in the trans position relative to the acetate-chelating arm that is attached to the central N atom. The Y3+ in Y(DTPA-BA2)(CH3OH) is nine-coordinated with an octadentate DTPA-BA2 and a methanol oxygen. The coordination geometry is best described as a tricapped trigonal prism. One benzylamine group is trans and the other cis to the acetate-chelating arm that is attached to the central N atom. All three M(DTPA-BA2) complexes (M = In, Y, and Lu) exist as at least three isomers in solution (approximately 10 mM), as shown by the presence of 6-8 overlapped 1H NMR signals from the methylene hydrogens of the benzylamine groups. The coordinated DTPA-BA2 remains rigid even at temperatures > 85 degrees C. The exchange rate between different isomers in M(DTPA-BA2) (M = In, Y, and Lu) is relatively slow at high concentrations (> 1.0 mM), but it is fast due to the partial dissociation and rapid interconversion of different isomers at lower concentrations ( approximately 10 mircroM). It is not surprising that M(DTPA-BA2) complexes (M = In, Y, and Lu) appear as a single peak in their respective HPLC chromatogram.
Collapse
Affiliation(s)
- Wen-Yuan Hsieh
- Department of Industrial and Physical Pharmacy, School of Pharmacy, Purdue University, 575 Stadium Mall Drive, West Lafayette, Indiana 47907, USA
| | | |
Collapse
|