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Host cell targeting of novel antimycobacterial 4-aminosalicylic acid derivatives with tuftsin carrier peptides. Eur J Pharm Biopharm 2022; 174:111-130. [DOI: 10.1016/j.ejpb.2022.03.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 03/08/2022] [Accepted: 03/24/2022] [Indexed: 11/23/2022]
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2
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Sanders VA, Iskhakov D, Abdel-Atti D, Devany M, Neary MC, Czerwinski KR, Francesconi LC. Synthesis, characterization and biological studies of rhenium, technetium-99m and rhenium-188 pentapeptides. Nucl Med Biol 2018; 68-69:1-13. [PMID: 30578134 DOI: 10.1016/j.nucmedbio.2018.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 10/19/2018] [Accepted: 11/01/2018] [Indexed: 02/05/2023]
Abstract
A pentapeptide macrocyclic ligand, KYCAR (lysyl-tyrosyl-cystyl-alanyl-arginine), has been designed as a potential chelating ligand for SPECT imaging and therapeutic in vivo agents. This study shows the synthesis and characterization of KYCAR complexes containing nonradioactive rhenium, 99mTc, or 188Re. The metal complexes were also biologically evaluated to determine in vivo distribution in healthy mice. The overall goals of this project were (1) to synthesize the Tc/Re pentapeptide complexes, (2) to identify spectroscopic methods for characterization of syn versus anti rhenium peptide complexes, (3) to analyze the ex vivo stability, and (4) to assess the biological properties of the [99mTc]TcO-KYCAR and [188Re]ReO-KYCAR complexes in vivo. Details on these efforts are provided below. METHODS NatRe/99mTc/188ReO-KYCAR complexes were synthesized, and macroscopic species were characterized via HPLC, IR, NMR, and CD. These characterization data were compared to the crystallographic data of ReO-KYC to assist in the assignment of diastereomers and to aid in the determination of the structure of the complex. RESULTS The radiometal complexes were synthesized with high purity (>95%). HPLC, IR, NMR and CD data on the macroscopic natReO-KYCAR complexes confirm the successful complexation as well as the presence of two diastereomers in syn and anticonformations. Tracer level complexes show favorable stabilities ex vivo for 2+ h. CONCLUSION Macroscopic metal complexes form diastereomers with the KYCAR ligand; however, this phenomenon is not readily observed on the tracer level due to the rapid interconversion. It was determined through pKa measurements that the macroscopic natReO-KYCAR complex is 0 at physiological pH. The [99mTc]TcO-KYCAR is stable in vitro while the [188Re]ReO-KYCAR shows 50% decomposition in PBS and serum. Biologically, the tracer level complexes clear through the hepatobiliary pathway. Some decomposition of both tracers is evident by uptake in the thyroid and stomach.
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Affiliation(s)
- Vanessa A Sanders
- Department of Chemistry, University of Nevada Las Vegas, Las Vegas, NV, USA; Department of Chemistry, Hunter College of the City University of New York, New York, NY, USA.
| | - David Iskhakov
- Department of Chemistry, Hunter College of the City University of New York, New York, NY, USA
| | - Dalya Abdel-Atti
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Matthew Devany
- Department of Chemistry, Hunter College of the City University of New York, New York, NY, USA
| | - Michelle C Neary
- Department of Chemistry, Hunter College of the City University of New York, New York, NY, USA
| | - Ken R Czerwinski
- Department of Chemistry, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Lynn C Francesconi
- Department of Chemistry, Hunter College of the City University of New York, New York, NY, USA; Department of Chemistry, Graduate Center of the City University of New York, New York, NY, USA
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3
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Benaki D, Zikos C, Karachaliou CE, Tsitsilonis O, Leondiadis L, Kalbacher H, Voelter W, Papadopoulos M, Pirmettis I, Pelecanou M, Livaniou E. Complexes of an Alpha Thymosin Derivative with185/187Re and99mTc: Structural Analysis and Initial Biological Evaluation. Chem Biol Drug Des 2012; 80:545-53. [DOI: 10.1111/j.1747-0285.2012.01425.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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4
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Horváti K, Bacsa B, Szabó N, Dávid S, Mező G, Grolmusz V, Vértessy B, Hudecz F, Bősze S. Enhanced cellular uptake of a new, in silico identified antitubercular candidate by peptide conjugation. Bioconjug Chem 2012; 23:900-7. [PMID: 22515329 DOI: 10.1021/bc200221t] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Mycobacterium tuberculosis is a successful pathogen, and it can survive in infected macrophages in dormant phase for years and decades. The therapy of tuberculosis takes at least six months, and the slow-growing bacterium is resistant to many antibiotics. The development of novel antimicrobials to counter the emergence of bacteria resistant to current therapies is urgently needed. In silico docking methods and structure-based drug design are useful bioinformatics tools for identifying new agents. A docking experiment to M. tuberculosis dUTPase enzyme, which plays a key role in the bacterial metabolism, has resulted in 10 new antitubercular drug candidates. The uptake of antituberculars by infected macrophages is limited by extracellular diffusion. The optimization of the cellular uptake by drug delivery systems can decrease the used dosages and the length of the therapy, and it can also enhance the bioavailability of the drug molecule. In this study, improved in vitro efficacy was achieved by attaching the TB5 antitubercular drug candidate to peptide carriers. As drug delivery components, (i) an antimicrobial granulysin peptide and (ii) a receptor specific tuftsin peptide were used. An efficient synthetic approach was developed to conjugate the in silico identified TB5 coumarone derivative to the carrier peptides. The compounds were effective on M. tuberculosis H37Rv culture in vitro; the chemical linkage did not affect the antimycobacterial activity. Here, we show that the OT20 tuftsin and GranF2 granulysin peptide conjugates have dramatically enhanced uptake into human MonoMac6 cells. The TB5-OT20 tuftsin conjugate exhibited significant antimycobacterial activity on M. tuberculosis H37Rv infected MonoMac6 cells and inhibited intracellular bacteria.
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Affiliation(s)
- Kata Horváti
- Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös L. University , Budapest, Hungary
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Pathuri G, Hedrick AF, Disch BC, Doan JT, Ihnat MA, Awasthi V, Gali H. Synthesis and evaluation of novel Tc-99m labeled probestin conjugates for imaging APN/CD13 expression in vivo. Bioconjug Chem 2011; 23:115-24. [PMID: 22148582 DOI: 10.1021/bc200546b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The enzyme aminopeptidase N (APN, also known as CD13) is known to play an important role in tumor proliferation, attachment, angiogenesis, and tumor invasion. In this study, we hypothesized that a radiolabeled high affinity APN inhibitor could be potentially useful for imaging APN expression in vivo. Here, we report synthesis, radiolabeling, and biological evaluation of new probestin conjugates containing a tripeptide, N,N-dimethylglycyl-l-lysinyl-l-cysteinylamide (N(3)S), chelator. New probestin conjugates were synthesized by solid-phase peptide synthesis method, purified by reversed-phase HPLC, and characterized by electrospray mass spectrometry. The conjugates were complexed with Re(V) and (99m)Tc(V) by transmetalation using corresponding Re(V) or (99m)Tc(V) gluconate synthon. The mass spectral analyses of ReO-N(3)S-Probestin conjugates were consistent with the formation of neutral Re(V)O-N(3)S complexes. Initial biological activity of ReO-N(3)S-Probestin conjugates determined by performing an in vitro APN enzyme assay using intact HT-1080 cells demonstrated higher inhibition of APN enzyme activity than bestatin. In vivo biodistribution and whole body planar imaging studies of (99m)TcO-N(3)S-PEG(2)-Probestin performed in nude mice xenografted with human fibrosarcoma tumors derived from HT-1080 cells demonstrated a tumor uptake value of 2.88 ± 0.64%ID/g with tumor-to-blood and tumor-to-muscle ratios of 4.8 and 5.3, respectively, at 1 h postinjection (p.i.). Tumors were clearly visible in whole body planar image obtained at 1 h p.i., but not when the APN was competitively blocked with a coinjection of excess nonradioactive ReO-N(3)S-PEG(2)-Probestin conjugate. These results demonstrate the feasibility of using high affinity APN inhibitor conjugates as targeting vectors for in vivo targeting of APN.
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Affiliation(s)
- Gopal Pathuri
- Department of Pharmaceutical Sciences, College of Pharmacy, The University of Oklahoma Health Sciences Center, 1110 N. Stonewall Avenue, Oklahoma City, OK 73117, United States
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6
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Gourni E, Bouziotis P, Benaki D, Loudos G, Xanthopoulos S, Paravatou-Petsotas M, Mavri-Vavagianni M, Pelecanou M, Archimandritis SC, Varvarigou AD. Structural Assessment and Biological Evaluation of Two N3S Bombesin Derivatives. J Med Chem 2009; 52:4234-46. [DOI: 10.1021/jm900360d] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Eleni Gourni
- Institutes of Radioisotopes—Radiodiagnostic Products and Biology, NCSR “Demokritos”, 15310 Athens, Greece
| | - Penelope Bouziotis
- Institutes of Radioisotopes—Radiodiagnostic Products and Biology, NCSR “Demokritos”, 15310 Athens, Greece
| | - Dimitra Benaki
- Institutes of Radioisotopes—Radiodiagnostic Products and Biology, NCSR “Demokritos”, 15310 Athens, Greece
| | - George Loudos
- Department of Medical Instruments Technology, Technological Educational Institute of Athens, Athens, Greece
| | - Stavros Xanthopoulos
- Institutes of Radioisotopes—Radiodiagnostic Products and Biology, NCSR “Demokritos”, 15310 Athens, Greece
| | - Maria Paravatou-Petsotas
- Institutes of Radioisotopes—Radiodiagnostic Products and Biology, NCSR “Demokritos”, 15310 Athens, Greece
| | | | - Maria Pelecanou
- Institutes of Radioisotopes—Radiodiagnostic Products and Biology, NCSR “Demokritos”, 15310 Athens, Greece
| | - Spyros C. Archimandritis
- Institutes of Radioisotopes—Radiodiagnostic Products and Biology, NCSR “Demokritos”, 15310 Athens, Greece
| | - Alexandra D. Varvarigou
- Institutes of Radioisotopes—Radiodiagnostic Products and Biology, NCSR “Demokritos”, 15310 Athens, Greece
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Bartholomä M, Valliant J, Maresca KP, Babich J, Zubieta J. Single amino acid chelates (SAAC): a strategy for the design of technetium and rhenium radiopharmaceuticals. Chem Commun (Camb) 2009:493-512. [PMID: 19283279 DOI: 10.1039/b814903h] [Citation(s) in RCA: 168] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Mark Bartholomä
- Department of Chemistry, Syracuse University, Syracuse, NY 13244, USA
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8
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Cantorias MV, Howell RC, Todaro L, Cyr JE, Berndorff D, Rogers RD, Francesconi LC. MO tripeptide diastereomers (M=99/99mTc, Re): models to identify the structure of 99mTc peptide targeted radiopharmaceuticals. Inorg Chem 2007; 46:7326-40. [PMID: 17691766 PMCID: PMC2270398 DOI: 10.1021/ic070077p] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Biologically active molecules, such as many peptides, serve as targeting vectors for radiopharmaceuticals based on 99mTc. Tripeptides can be suitable chelates and are easily and conveniently synthesized and linked to peptide targeting vectors through solid-phase peptide synthesis and form stable TcVO complexes. Upon complexation with [TcO]3+, two products form; these are syn and anti diastereomers, and they often have different biological behavior. This is the case with the approved radiopharmaceutical [99mTcO]depreotide ([99mTcO]P829, NeoTect) that is used to image lung cancer. [99mTcO]depreotide indeed exhibits two product peaks in its HPLC profile, but assignment of the product peaks to the diastereomers has proven to be difficult because the metal peptide complex is difficult to crystallize for structural analysis. In this study, we isolated diastereomers of [99TcO] and [ReO] complexes of several tripeptide ligands that model the metal chelator region of [99mTcO]depreotide. Using X-ray crystallography, we observed that the early eluting peak (A) corresponds to the anti diastereomer, where the Tc=O group is on the opposite side of the plane formed by the ligand backbone relative to the pendant groups of the tripeptide ligand, and the later eluting peak (B) corresponds to the syn diastereomer, where the Tc=O group is on the same side of the plane as the residues of the tripeptide. 1H NMR and circular dichroism (CD) spectroscopy report on the metal environment and prove to be diagnostic for syn or anti diastereomers, and we identified characteristic features from these techniques that can be used to assign the diastereomer profile in 99mTc peptide radiopharmaceuticals like [99mTcO]depreotide and in 188Re peptide radiotherapeutic agents. Crystallography, potentiometric titration, and NMR results presented insights into the chemistry occurring under physiological conditions. The tripeptide complexes where lysine is the second amino acid crystallized in a deprotonated metallo-amide form, possessing a short N1-M bond. The pKa measurements of the N1 amine (pKa approximately 5.6) suggested that this amine is rendered more acidic by both metal complexation and the presence of the lysine residue. Furthermore, peptide chelators incorporating a lysine (like the chelator of [TcO]depreotide) likely exist in the deprotonated form in vivo, comprising a neutral metal center. Deprotonation possibly mediates the interconversion process between the syn and anti diastereomers. The N1 amine group on non-lysine-containing metallopeptides is not as acidic (pKa approximately 6.8) and does not deprotonate and crystallize as do the metallo-amide species. Three of the tripeptide ligands (FGC, FSC, and FKC) were radiolabeled with 99mTc, and the individual syn and anti isomers were isolated for biodistribution studies in normal female nude mice. The main organs of uptake were the liver, intestines, and kidneys, with the FGC compounds exhibiting the highest liver uptake. In comparing the diastereomers, the syn compounds had substantially higher organ uptake and slower blood clearance than the anti compounds.
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Affiliation(s)
- Melchor V. Cantorias
- Department of Chemistry, Hunter College and the Graduate Center of the City University of New York, 695 Park Avenue, New York, New York 10021
| | - Robertha C. Howell
- Department of Chemistry, Hunter College and the Graduate Center of the City University of New York, 695 Park Avenue, New York, New York 10021
| | - Louis Todaro
- Department of Chemistry, Hunter College and the Graduate Center of the City University of New York, 695 Park Avenue, New York, New York 10021
| | - John E. Cyr
- Research Laboratories of Schering AG, Radiopharmaceuticals Research, Berlin, Germany
| | - Dietmar Berndorff
- Research Laboratories of Schering AG, Radiopharmaceuticals Research, Berlin, Germany
| | - Robin D. Rogers
- Department of Chemistry, University of Alabama, Tuscaloosa, Alabama 35487
| | - Lynn C. Francesconi
- Department of Chemistry, Hunter College and the Graduate Center of the City University of New York, 695 Park Avenue, New York, New York 10021
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Cyr JE, Pearson DA, Nelson CA, Lyons BA, Zheng Y, Bartis J, He J, Cantorias MV, Howell RC, Francesconi LC. Isolation, characterization, and biological evaluation of syn and anti diastereomers of [(99m)Tc]technetium depreotide: a somatostatin receptor binding tumor imaging agent. J Med Chem 2007; 50:4295-303. [PMID: 17691760 PMCID: PMC2330168 DOI: 10.1021/jm060887v] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The early and later eluting [(99m)TcO]depreotide products on RP-HPLC were confirmed to be the anti and syn diastereomers, respectively, based on proton NMR and circular dichroism spectroscopy. NMR provided evidence of a folded, conformationally constrained structure for the syn diastereomer. The syn diastereomer is predominant (anti/syn approximately 10:90) in the [(99m)TcO]depreotide preparation and shows a slightly higher affinity (IC50 = 0.15 nM) for the somatostatin receptor than the anti diastereomer (IC50 = 0.89 nM). Both diastereomers showed higher binding affinities than the free peptide (IC(50) = 7.4 nM). Biodistribution studies in AR42J tumor xenograft nude mice also showed higher tumor uptake for syn [(99m)TcO]depreotide (6.58% ID/g) than for the anti [(99m)TcO]depreotide (3.38% ID/g). Despite the differences in biological efficacy, the favorable binding affinity, tumor uptake, and tumor-to-background ratio results for both diastereomeric species predict that both are effective for imaging somatostatin receptor-positive tumors in vivo.
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Affiliation(s)
- John E. Cyr
- Diatide Research Laboratories, 9 Delta Drive, Londonderry, New Hampshire 03053
- Research Laboratories of Schering AG, Radiopharmaceuticals Research, Berlin, Germany
- * To whom correspondence should be addressed. John Cyr, Bayer Healthcare Pharmaceuticals, 2600 Hilltop Dr., Richmond, California 94804. Phone: (510) 669-4225. Fax: (510) 669-4770. E-mail: . Lynn C. Francesconi, Department of Chemistry, Hunter College and the Graduate Center of the City University of New York, New York, New York 10021. Phone: (212) 772-5353. Fax: (212) 772-5332. E-mail:
| | - Daniel A. Pearson
- Diatide Research Laboratories, 9 Delta Drive, Londonderry, New Hampshire 03053
| | - Carol A. Nelson
- Diatide Research Laboratories, 9 Delta Drive, Londonderry, New Hampshire 03053
| | - Barbara A. Lyons
- University of Vermont College of Medicine, Burlington, Vermont 05405
| | - Yongyong Zheng
- Department of Chemistry, Hunter College and the Graduate Center of the City University of New York, 695 Park Avenue, New York, New York 10021
| | - Judit Bartis
- Department of Chemistry, Hunter College and the Graduate Center of the City University of New York, 695 Park Avenue, New York, New York 10021
| | - Jiafang He
- Department of Chemistry, Hunter College and the Graduate Center of the City University of New York, 695 Park Avenue, New York, New York 10021
| | - Melchor V. Cantorias
- Department of Chemistry, Hunter College and the Graduate Center of the City University of New York, 695 Park Avenue, New York, New York 10021
| | - Robertha C. Howell
- Department of Chemistry, Hunter College and the Graduate Center of the City University of New York, 695 Park Avenue, New York, New York 10021
| | - Lynn C. Francesconi
- Department of Chemistry, Hunter College and the Graduate Center of the City University of New York, 695 Park Avenue, New York, New York 10021
- * To whom correspondence should be addressed. John Cyr, Bayer Healthcare Pharmaceuticals, 2600 Hilltop Dr., Richmond, California 94804. Phone: (510) 669-4225. Fax: (510) 669-4770. E-mail: . Lynn C. Francesconi, Department of Chemistry, Hunter College and the Graduate Center of the City University of New York, New York, New York 10021. Phone: (212) 772-5353. Fax: (212) 772-5332. E-mail:
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10
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He H, Lipowska M, Xu X, Taylor AT, Marzilli LG. Rhenium analogues of promising renal imaging agents with a [99mTc(CO)3]+ core bound to cysteine-derived dipeptides, including lanthionine. Inorg Chem 2007; 46:3385-94. [PMID: 17375908 DOI: 10.1021/ic0619299] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The coordination chemistry of lanthionine (LANH2) and cystathionine (CSTH2) dipeptides, which respectively consist of two cysteines and one cysteine and one homocysteine linked by a thioether bridge, is almost unstudied. Recently for fac-[99mTc(CO)3(LAN)]- isomers, the first small 99mTc(CO)3 agents evaluated in humans were found to give excellent renal images and to have a high specificity for renal excretion. Herein we report the synthesis and characterization of Re complexes useful for interpreting the nature of tracer 99mTc radiopharmaceuticals. Treatment of [Re(CO)3(H2O)3]OTf with commercially available LANH2 (a mixture of meso (d,l) and chiral (dd,ll) isomers) gave three HPLC peaks, 1A, 1B, and 1C, but treatment with CSTH2 (l,l isomer) gave one major product, Re(CO)3(CSTH) (2). Crystalline Re(CO)3(LANH) products were best obtained with synthetic LANH2, richer in meso or chiral isomers. X-ray crystallography showed that these dipeptides coordinate as tridentate N2S-bound ligands with two dangling carboxyls. The LANH ligand is meso in 1A and 1C and chiral in 1B. While 1A (kinetically favored) is stable at ambient temperature for days, it converted into 1C (thermodynamically favored) at 100 degrees C; after 6 h, equilibrium was reached at a 1A:1C ratio of 1:2 at pH 8. The structures provide a rationale for this behavior and for the fact that 1A and 1C have simple NMR spectra. This simplicity results from fluxional interchange between an enantiomer with both chelate rings having the same delta pucker and an enantiomer with both chelate rings having the same lambda pucker. Agents with the [99mTc(CO)3]+ core and N2S ligands show promise of becoming an important class of 99mTc radiopharmaceuticals. The chemistry of Re analogues with these ligands, such as the LAN2- complexes reported here, provides a useful background for designing new small agents and also tagged large agents because two uncoordinated carboxyl groups are available for conjugation with biological molecules such as proteins.
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Affiliation(s)
- Haiyang He
- Department of Radiology, Emory University, Atlanta, Georgia 30322, and Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803
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Méndez-Rojas MA, Kharisov BI, Tsivadze AY. Recent advances on technetium complexes: coordination chemistry and medical applications¶. J COORD CHEM 2007. [DOI: 10.1080/00958970500324633] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Miguel A. Méndez-Rojas
- a Departamento de Química y Biología , Universidad de las Américas-Puebla , Ex-Hacienda de Sta. Catarina Martir, AP 100, Cholula 72820, Puebla, México
| | - Boris I. Kharisov
- b Facultad de Ciencias Químicas , Universidad Autónoma de Nuevo León , 66450 San Nicolas de los Garza 18-F, Nuevo León, México
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He H, Lipowska M, Xu X, Taylor AT, Carlone M, Marzilli LG. Re(CO)(3) complexes synthesized via an improved preparation of aqueous fac-[Re(CO)(3)(H(2)O)(3)](+) as an aid in assessing (99m)Tc imaging agents. Structural characterization and solution behavior of complexes with thioether-bearing amino acids as tridentate ligands. Inorg Chem 2005; 44:5437-46. [PMID: 16022542 DOI: 10.1021/ic0501869] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Parallel studies of the preparation of Re and (99m)Tc agents aid in interpreting the nature of tracer (99m)Tc radiopharmaceuticals. Aqueous solutions of the fac-[(99m)Tc(CO)(3)(H(2)O)(3)](+) cation are gaining wide use and are readily prepared, but such solutions of the fac-[Re(CO)(3)(H(2)O)(3)](+) cation (1) are not so easily accessible. Herein we describe a new, reliable, and straightforward preparation of aqueous solutions of 1, characterized by HPLC and ESI-MS. Treatment of solutions of 1 with thioether-bearing amino acids, AAH = S-methyl-l-cysteine (MECYSH), S-propyl-l-cysteine (PRCYSH), and methionine (METH), gave high yields of fac-Re(CO)(3)AA complexes. X-ray crystallographic and NMR analyses indicated that MECYS(-), PRCYS(-), and MET(-) were bound in fac-Re(CO)(3)AA complexes as tridentate monoanionic ligands through amino, thioether, and alpha-carboxyl groups. In CD(3)OD, (1)H NMR spectra have broad signals but have two sets of signals at -10 degrees C, consistent with two isomers with different configurations at the pyramidal sulfur; these interconvert slowly on the NMR time scale at low temperatures. Indeed, the crystal structure of the fac-Re(CO)(3)(PRCYS) reveals a mixture of the two possible diastereoisomers. S-(Carboxymethyl)-l-cysteine (CCMH(2)) and 1 gave two products, 5A (kinetically favored) and 5B (thermodynamically favored). X-ray crystallographic analyses of a crystal of 5B and of a 1:1 cocrystal of 5A and 5B showed that 5A and 5B are diastereoisomers with the CCMH(-) alpha-carboxyl group dangling. In addition to the amino and thioether groups, the S-(carboxymethyl) carboxyl group is coordinated, a feature that slows interconversion of diastereoisomers relative to the other fac-Re(CO)(3)AA complexes because interconversion can now occur only after the rupture of Re-ligand bonds. These N, O, and S tridentate adducts are quite stable, and the grouping has promise in (99m)Tc(CO)(3) tracer development.
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Affiliation(s)
- Haiyang He
- Department of Radiology, Emory University, Atlanta, Georgia 30322, USA
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Banerjee SR, Maresca KP, Francesconi L, Valliant J, Babich JW, Zubieta J. New directions in the coordination chemistry of 99mTc: a reflection on technetium core structures and a strategy for new chelate design. Nucl Med Biol 2005; 32:1-20. [PMID: 15691657 DOI: 10.1016/j.nucmedbio.2004.09.001] [Citation(s) in RCA: 153] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2004] [Revised: 08/31/2004] [Accepted: 09/01/2004] [Indexed: 11/26/2022]
Abstract
Bifunctional chelates offer a general approach for the linking of radioactive metal cations to macromolecules. In the specific case of 99mTc, a variety of technologies have been developed for assembling a metal-chelate-biomolecule complex. An evaluation of these methodologies requires an appreciation of the coordination characteristics and preferences of the technetium core structures and oxidation states, which serve as platforms for the development of the imaging agent. Three technologies, namely, the MAG3-based bifunctional chelates, the N-oxysuccinimidylhydrazino-nicotinamide system and the recently described single amino acid chelates for the {Tc(CO)3}1+ core, are discussed in terms of the fundamental coordination chemistry of the technetium core structures. In assessing the advantages and disadvantages of these technologies, we conclude that the single amino acid analogue chelates (SAAC), which are readily conjugated to small peptides by solid-phase synthesis methods and which form robust complexes with the {Tc(CO)3}1+ core, offer an effective alternative to the previously described methods.
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Affiliation(s)
- Sangeeta Ray Banerjee
- Department of Chemistry, Syracuse University, Center for Science and Technology, Syracuse, NY 13244, USA
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14
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Costopoulos B, Benaki D, Pelecanou M, Mikros E, Stassinopoulou CI, Varvarigou AD, Archimandritis SC. Structural Study by NMR of an Oxorhenium−RGD Decapeptide Complex for Application in Radiotherapy. Inorg Chem 2004; 43:5598-602. [PMID: 15332811 DOI: 10.1021/ic049519c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The decapeptide Arg-Gly-Asp-Ser-Cys-Arg-Gly-Asp-Ser-Tyr, which contains two Arg-Gly-Asp (RGD) moieties in its sequence, has been successfully labeled with radioactive rhenium (Re-188) yielding a single, stable oxorhenium complex. This complex is being evaluated for possible application in oncology as a target-specific radiotherapeutic agent, because its radioactive technetium-99m analogue has already been applied for the scintigraphic detection of malignant melanoma in humans. For structural characterization purposes, the complex of the decapeptide was synthesized at the macroscopic level using nonradioactive rhenium (Re-185/Re-187). NMR and mass spectral analysis of the nonradioactive oxorhenium complex revealed that the decapeptide coordinates to the oxorhenium core through the N(amide) of Asp3, the N(amide) of Ser4, and the N(amide) and S(thiolate) atoms of Cys5 to form a complex of the ReO[N(3)S] type.
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Affiliation(s)
- Basil Costopoulos
- Institutes of Radioisotopes & Radiodiagnostic Products and Biology, National Centre for Scientific Research Demokritos, 153 10 Athens, Greece
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Francesconi LC, Zheng Y, Bartis J, Blumenstein M, Costello C, De Rosch MA. Preparation and Characterization of [99TcO] Apcitide: A Technetium Labeled Peptide. Inorg Chem 2004; 43:2867-75. [PMID: 15106974 DOI: 10.1021/ic035473w] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[99mTcO] apcitide (99mTcO(P246)), the technetium complex of the 13 amino acid, apcitide, cyclo-(D-Tyr-Apc-Gly-Asp-Cys)-Gly-Gly-Cys(Acm)-Gly-Cys(Acm)-Gly-Gly-Cys-NH2, where Apc is L-[S-(3-aminopropyl)]cysteine (an arginine mimetic) and Acm is the acetamidomethyl protecting group, has high affinity and selectivity for the GPIIb/IIIa receptor that is expressed on the membrane surface of activated platelets and plays an integral role in platelet aggregation and thrombus formation. Bibapcitide, a 26 amino acid, bis-succinimidomethyl ether-linked dimer of the peptide apcitide has been formulated as a single-vial, lyophilized kit having the trade name AcuTect. When sterile, nonpyrogenic sodium pertechnetate (99mTcO4-) in 0.9% sodium chloride is added to the AcuTect radiopharmaceutical kit and the resulting kit is heated, [99mTcO] apcitide forms. This is the first radiopharmaceutical to target acute deep vein thrombosis (DVT) in the lower extremities. We report here the preparation, purification, and isolation of the 99Tc complex of apcitide and its characterization to determine the mode of binding of Tc to apcitide. [99TcO] apcitide was prepared, on the macroscopic level, by reaction of [99TcOCl4]- with apcitide, purified by preparative HPLC and isolated as a trifluoroacetate salt. [99TcO] apcitide can also be formed from the reaction of bibapcitide and 99TcO4- in the presence of Sn(II) and glucoheptonate at 80 degrees C, conditions that mimic the radiopharmaceutical kit preparation. FTIR data show a Tc=O stretch at 961.2 cm(-1), in the range observed for anionic [TcVO]3+ amide thiolate complexes. The mass spectral data is in agreement with the formula, [C51H73O20N17S5Tc]-, consistent with retention of Acm groups and the Tc binding in the Gly11-Gly12-Cys13 region of the peptide. Despite significant spectral overlap due to numerous similar amino acids, all protons of apcitide and [99TcO] apcitide were unambiguously assigned. The observation of two nonequivalent Acm groups and the observation of only 10 NH-CH cross-peaks in the TOCSY and COSY spectra of [99TcO] apcitide (NH-CH cross-peaks were absent for Gly11-Gly12-Cys13), compared to all 13 cross-peaks found in apcitide, provided compelling evidence to support the 99Tc binding to the terminal Gly11-Gly12-Cys13 region of apcitide.
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Affiliation(s)
- Lynn C Francesconi
- Department of Chemistry, Hunter College and the Graduate School of the City University of New York, New York, New York 10021, USA.
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