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Lewis NA, Marzilli PA, Fronczek FR, Marzilli LG. Models for B12-conjugated radiopharmaceuticals. Cobaloxime binding to new fac-[Re(CO)3(Me2bipyridine)(amidine)]BF4 complexes having an exposed pyridyl nitrogen. Inorg Chem 2014; 53:11096-107. [PMID: 25285912 DOI: 10.1021/ic5016675] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
New mononuclear amidine complexes, fac-[Re(CO)3(Me2bipy)(HNC(CH3)(pyppz))]BF4 [(4,4'-Me2bipy (1), 5,5'-Me2bipy (2), and 6,6'-Me2bipy (3)] (bipy = 2,2'-bipyridine), were synthesized by treating the parent fac-[Re(I)(CO)3(Me2bipy)(CH3CN)]BF4 complex with the C2-symmetrical amine 1-(4-pyridyl)piperazine (pyppzH). The axial amidine ligand has an exposed, highly basic pyridyl nitrogen. The reaction of complexes 1-3 with a B12 model, (py)Co(DH)2Cl (DH = monoanion of dimethylglyoxime), in CH2Cl2 yielded the respective dinuclear complexes, namely, fac-[Re(CO)3(Me2bipy)(μ-(HNC(CH3)(pyppz)))Co(DH)2Cl]BF4 [(4,4'-Me2bipy (4), 5,5'-Me2bipy (5), and 6,6'-Me2bipy (6)]. (1)H NMR spectroscopic analysis of all compounds and single-crystal X-ray crystallographic data for 2, 3, 5, and 6 established that the amidine had only the E configuration in both the solid and solution states and that the pyridyl group is bound to Co in 4-6. Comparison of the NMR spectra of 1-3 with spectra of 4-6 reveals an unusually large "wrong-way" upfield shift for the pyridyl H2/6 signal for 4-6. The wrong-way H2/6 shift of (4-Xpy)Co(DH)2Cl (4-Xpy = 4-substituted pyridine) complexes increased with increasing basicity of the 4-Xpy derivative, a finding attributed to the influence of the magnetic anisotropy of the cobalt center on the shifts of the (1)H NMR signals of the pyridyl protons closest to Co. Our method of employing a coordinate bond for conjugating the fac-[Re(I)(CO)3] core to a vitamin B12 model could be extended to natural B12 derivatives. Because B12 compounds are known to accumulate in cancer cells, such an approach is a very attractive method for the development of (99m)Tc and (186/188)Re radiopharmaceuticals for targeted tumor imaging and therapy.
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Affiliation(s)
- Nerissa A Lewis
- Department of Chemistry, Louisiana State University , Baton Rouge, Louisiana 70803, United States
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52
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Abstract
Minute doses of a complex cofactor cobalamin (Cbl, vitamin B12) are essential for metabolism. The nutritional chain for humans includes: (1) production of Cbl by bacteria in the intestinal tract of herbivores; (2) accumulation of the absorbed Cbl in animal tissues; (3) consumption of food of animal origin. Most biological sources contain both Cbl and its analogues, i.e. Cbl-resembling compounds physiologically inactive in animal cells. Selective assimilation of the true vitamin requires an interplay between three transporting proteins - haptocorrin (HC), intrinsic factor (IF), transcobalamin (TC) - and several receptors. HC is present in many biological fluids, including gastric juice, where it assists in disposal of analogues. Gastric IF selectively binds dietary Cbl and enters the intestinal cells via receptor-mediated endocytosis. Absorbed Cbl is transmitted to TC and delivered to the tissues with blood flow. The complex transport system guarantees a very efficient uptake of the vitamin, but failure at any link causes Cbl-deficiency. Early detection of a negative B12 balance is highly desirable to prevent irreversible neurological damages, anaemia and death in aggravated cases. The review focuses on the molecular mechanisms of cobalamin transport with emphasis on interaction of corrinoids with the specific proteins and protein-receptor recognition. The last section briefly describes practical aspects of recent basic research concerning early detection of B12-related disorders, medical application of Cbl-conjugates, and purification of corrinoids from biological samples.
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Affiliation(s)
- Sergey N Fedosov
- Protein Chemistry Laboratory, Department of Molecular Biology, University of Aarhus, Aarhus, Denmark,
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53
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Hunger M, Mutti E, Rieder A, Enders B, Nexo E, Kräutler B. Organometallic B12-DNA conjugate: synthesis, structure analysis, and studies of binding to human B12-transporter proteins. Chemistry 2014; 20:13103-7. [PMID: 25168390 DOI: 10.1002/chem.201404359] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Indexed: 11/12/2022]
Abstract
Design, synthesis, and structural characterization of a B12-octadecanucleotide are presented herein, a new organometallic B12-DNA conjugate. In such covalent conjugates, the natural B12 moiety may be a versatile vector for controlled in vivo delivery of oligonucleotides to cellular targets in humans and animals, through the endogenous B12 transport systems. Binding of the organometallic B12 octadecanucleotide to the three important human proteins of B12 transport was studied, to examine its structural suitability for the task of eventual in vivo oligonucleotide delivery. Binding was efficient with transcobalamin (TC), but not so efficient with the homologous glycoproteins intrinsic factor and haptocorrin. Binding of the B12 octadecanucleotide to TC suggests the capacity of the B12 moiety to serve as a natural vector for specific transport of single stranded, organometallic oligonucleotide loads from the blood stream into cells.
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Affiliation(s)
- Miriam Hunger
- Institute of Organic Chemistry and Center for Molecular Biosciences (CMBI), Innrain 80/82, University of Innsbruck, 6020 Innsbruck (Austria)
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54
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Ikotun OF, Marquez BV, Fazen CH, Kahkoska AR, Doyle RP, Lapi SE. Investigation of a vitamin B12 conjugate as a PET imaging probe. ChemMedChem 2014; 9:1244-51. [PMID: 24753453 DOI: 10.1002/cmdc.201400048] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Indexed: 12/29/2022]
Abstract
Nutrient demand is a fundamental characteristic of rapidly proliferating cells. Vitamin B12 is vital for cell proliferation; thus neoplastic cells have an increased demand for this essential nutrient. In this study we exploited the vitamin B12 uptake pathway to probe the nutritional demand of proliferating cells with a radiolabeled B12 derivative in various preclinical tumor models. We describe the synthesis and biological evaluations of copper-64-labeled B12 -ethylenediamine-benzyl-1,4,7-triazacyclononane-N,N',N''-triacetic acid (B12 -en-Bn-NOTA-(64) Cu), the first example of a B12 derivative for positron emission tomography (PET) imaging. Small-animal imaging and pharmacological evaluation show high tumor uptake ranging from 2.20 to 4.84% ID g(-1) at 6 h post-administration. Competition studies with excess native B12 resulted in a 95% decrease in tumor accumulation, indicating the specificity of this radiopharmaceutical for B12 endocytotic transport proteins. These results show that a vitamin B12 PET radiopharmaceutical has potential utility for non-invasive imaging of enhanced nutrient demand in proliferating cells.
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Affiliation(s)
- Oluwatayo F Ikotun
- Department of Radiological Sciences, Washington University School of Medicine, 510 S. Kingshighway Blvd., Campus Box 8225, St. Louis, MO 63110 (USA), Fax: (+1) 315-362-4696
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55
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Czömpöly T, Langmár Z, Bors M, Zsákai C, Géczy M, Kulcsár G. Safety, tolerability, and effect on quality of life of a mixture of amino acids and other small molecules in cancer patients. Cancer Biother Radiopharm 2014; 29:124-34. [PMID: 24502241 DOI: 10.1089/cbr.2013.1573] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We performed two clinical studies to evaluate the safety, tolerability, and effect on quality of life of a product containing a mixture of amino acids, vitamins, and other small molecules. In the first one period, open-label, multiple-dose study, the safety and tolerability of a 1-week administration was evaluated in 24 healthy volunteers. In the second one period, open-label, multiple-dose, single-arm study, we investigated the safety, tolerability, and effect on quality of life of a 4-week administration in 50 cancer patients. The safety assessment included the monitoring of adverse events, changes in physical status, and clinical laboratory tests. Changes in quality of life were measured with the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 version 3.0 (EORTC QLQ-C30). We have found that administration of the investigated product is safe and well tolerated in healthy individuals and in cancer patients. Administration of the product to cancer patients significantly improved their quality of life (EORTC QLQ-C30 global health status score: baseline: 24.17 ± 9.2; end of treatment: 47.08 ± 14.56, p<0.001). To evaluate the anticancer activity of the investigated product in humans, a randomized, blinded, combination clinical trial should be conducted.
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Affiliation(s)
- Tamás Czömpöly
- 1 Cancer Research and Drug Development Center, Culevit Ltd. , Pécs, Hungary
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56
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Coogan MP, Doyle RP, Valliant JF, Babich JW, Zubieta J. Single amino acid chelate complexes of the M(CO)3 (+) core for correlating fluorescence and radioimaging studies (M = (99m) Tc or Re). J Labelled Comp Radiopharm 2014; 57:255-61. [PMID: 24395431 DOI: 10.1002/jlcr.3164] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 10/29/2013] [Indexed: 01/03/2023]
Abstract
Single amino acid chelates (SAACs) and SAAC-like bifunctional ligands can be exploited in the design of a variety of bioconjugates for facile metallation with the M(CO)3 (+) unit with M = (99m) Tc or Re. When the donor groups of the ligand are quinolone, thiazole or other similarly conjugated heterocycles, the rhenium complexes are fluorescent, affording complementary and isostructural fluorescent probes to the radioactive (99m) Tc analogues. The versatility of the approach has been demonstrated by the preparation of bioconjugates incorporating peptides, biotin, folic acid, thymidine and vitamin B12 . In addition, the unusual photophysical properties observed for rhenium of the [bisthiazole-diamino butane-Re(CO)3 (+) ] derivative [BTBA-Re(CO)3 ](+) are discussed.
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Affiliation(s)
- Michael P Coogan
- School of Chemistry and Chemical Biology, University of Lancaster, Lancaster, LA1 4YB, UK
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57
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Genç L, Kutlu HM, Güney G. Vitamin B12-loaded solid lipid nanoparticles as a drug carrier in cancer therapy. Pharm Dev Technol 2013; 20:337-44. [DOI: 10.3109/10837450.2013.867447] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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58
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Sah BR, Schibli R, Waibel R, von Boehmer L, Bläuenstein P, Nexo E, Johayem A, Fischer E, Müller E, Soyka JD, Knuth AK, Haerle SK, Schubiger PA, Schaefer NG, Burger IA. Tumor Imaging in Patients with Advanced Tumors Using a New 99mTc-Radiolabeled Vitamin B12 Derivative. J Nucl Med 2013; 55:43-9. [DOI: 10.2967/jnumed.113.122499] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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59
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Núñez-Montenegro A, Carballo R, Abram U, Vázquez-López EM. Preparation and characterization of rhenium(I) complexes with thiosemicarbazone ligands derived from resorcinol. Polyhedron 2013. [DOI: 10.1016/j.poly.2013.08.038] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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60
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Mutti E, Ruetz M, Birn H, Kräutler B, Nexo E. 4-ethylphenyl-cobalamin impairs tissue uptake of vitamin B12 and causes vitamin B12 deficiency in mice. PLoS One 2013; 8:e75312. [PMID: 24073261 PMCID: PMC3779197 DOI: 10.1371/journal.pone.0075312] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 08/13/2013] [Indexed: 11/18/2022] Open
Abstract
Coβ-4-ethylphenyl-cob(III) alamin (EtPhCbl) is an organometallic analogue of vitamin B12 (CNCbl) which binds to transcobalamin (TC), a plasma protein that facilitates the cellular uptake of cobalamin (Cbl). In vitro assays with key enzymes do not convert EtPhCbl to the active coenzyme forms of Cbl suggesting that administration of EtPhCbl may cause cellular Cbl deficiency. Here, we investigate the in vivo effect of EtPhCbl in mice and its ability, if any, to induce Cbl deficiency. We show that EtPhCbl binds to mouse TC and we examined mice that received 3.5 nmol/24h EtPhCbl (n=6), 3.5 nmol/24h CNCbl (n=7) or NaCl (control group) (n=5) through osmotic mini-pumps for four weeks. We analyzed plasma, urine, liver, spleen, submaxillary glands and spinal cord for Cbl and markers of Cbl deficiency including methylmalonic acid (MMA) and homocysteine (tHcy). Plasma MMA (mean±SEM) was elevated in animals treated with EtPhCbl (1.01±0.12 µmol/L) compared to controls (0.30±0.02 µmol/L) and CNCbl (0.29±0.01 µmol/L) treated animals. The same pattern was observed for tHcy. Plasma total Cbl concentration was higher in animals treated with EtPhCbl (128.82±1.87 nmol/L) than in CNCbl treated animals (87.64±0.93 nmol/L). However, the organ levels of total Cbl were significantly lower in animals treated with EtPhCbl compared to CNCbl treated animals or controls, notably in the liver (157.07±8.56 pmol/g vs. 603.85±20.02 pmol/g, and 443.09±12.32 pmol/g, respectively). Differences between the three groups was analysed using one-way ANOVA and, Bonferroni post-hoc test. EtPhCbl was present in all tissues, except the spinal cord, accounting for 35-90% of total Cbl. In conclusion, treatment with EtPhCbl induces biochemical evidence of Cbl deficiency. This may in part be caused by a compromised tissue accumulation of Cbl.
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Affiliation(s)
- Elena Mutti
- Department of Clinical Biochemistry, Aarhus University Hospital, Aarhus, Denmark
| | - Markus Ruetz
- Institute of Organic Chemistry and Centre of Molecular Biosciences, University of Innsbruck, Innsbruck, Austria
| | - Henrik Birn
- Department of Nephrology, Aarhus University Hospital and Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Bernhard Kräutler
- Institute of Organic Chemistry and Centre of Molecular Biosciences, University of Innsbruck, Innsbruck, Austria
| | - Ebba Nexo
- Department of Clinical Biochemistry, Aarhus University Hospital, Aarhus, Denmark
- * E-mail:
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61
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Rutkowska-Zbik D, Mazur G, Drzewiecka-Matuszek A, Orzeł Ł, Stochel G. Exploring novel modified vitamin B12 as a drug carrier: forecast from density functional theory modeling. J Phys Chem B 2013; 117:9655-61. [PMID: 23889131 DOI: 10.1021/jp405821k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Three non-native derivatives of vitamin B12 with imidazole, ethylenediamine, and pyrazine as cobalt(III) β-ligands were characterized by applying the BP/def2-TZVP density functional method. The binding of all three ligands is thermodynamically favorable. It is proposed that their synthesis might be possible from aquacobalamin as a starting form of vitamin B12, as has been done in the case of an imidazole derivative of B12 (Hannibal et al. Inorg. Chem. 2007, 46, 3613-3618). Furthermore, the possibility of the formation of their conjugates with cisplatin is investigated. The proposed β-ligands may serve as bridging ligands, binding to the platin ion as N-donors. In parallel, the calculations are done for the previously synthetized B12-cisplatin adduct with CN(-) as a bridging ligand and are compared with available experimental data, allowing assessment of the applied computational protocol. A good agreement between the computed and experimental structural parameters is obtained. In each of the studied structures, the Co-β-ligand bond is weaker than the Pt-β-ligand bond.
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Affiliation(s)
- Dorota Rutkowska-Zbik
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Kraków, Poland.
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62
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Macias JD, Gerkin RD, Locke D, Macias MP. Differential gene expression in cholesteatoma by DNA chip analysis. Laryngoscope 2013; 123 Suppl S5:S1-21. [PMID: 23670528 DOI: 10.1002/lary.24176] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 03/20/2013] [Accepted: 04/03/2013] [Indexed: 11/10/2022]
Abstract
OBJECTIVES/HYPOTHESIS In contrast to normal epithelium, the desquamating stratified squamous epithelium of temporal bone cholesteatoma characteristically exhibits sustained hyperproliferative growth and a capacity for bone erosion. We conducted genome-wide microarray analyses to determine the molecular nature of cholesteatoma's biological processes and identify disease-associated, altered gene activity. We tested the hypothesis that genes contributing to the pathophysiology of cholesteatoma are differentially expressed compared to control tissue. STUDY DESIGN Prospective experimental analysis. METHODS Using new, enhanced microarray platforms and well-annotated human transcriptome probes, we measured global gene expression levels in surgical specimens of cholesteatoma and in the corresponding normal postauricular skin in four patients. Genes of interest were verified by quantitative real time reverse transcriptase polymerase chain reaction analyses using cholesteatoma and postauricular sample pairs (n = 13). External auditory canal skin from six additional patients was also evaluated as a normal control. Immunohistochemistry detected protein expression in tissue sections and the cells involved. RESULTS DNA chip analyses identified 282 differentially expressed genes in cholesteatoma compared to control samples. Of these, 104 genes were upregulated and 178 were downregulated. Ontological classifications indicate relationships to cellular processes including receptor binding, cell communication and motion, vitamin metabolism, and cytokine-mediated inflammation. Based on potential involvement in disease pathology, 10 genes were selected and independently verified by quantitative polymerase chain reaction. Immunohistochemical detection of transcobalamin-1 and CCL27 implicates cholesteatoma keratinocytes and dermal endothelial cells as contributors in disease processes. CONCLUSIONS We present a comprehensive, human genome-wide survey of disease-associated gene expression that extends the public database and provides new evidence for molecular mechanisms involved in cholesteatoma pathology. Laryngoscope, 123:S1-S21, 2013.
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Affiliation(s)
- John D Macias
- Macias Otology , Phoenix, Arizona, U.S.A; Biomedical Research Program, the EAR Foundation of Arizona , Phoenix, Arizona, U.S.A
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63
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Krall N, Scheuermann J, Neri D. Small Targeted Cytotoxics: Current State and Promises from DNA-Encoded Chemical Libraries. Angew Chem Int Ed Engl 2013; 52:1384-402. [DOI: 10.1002/anie.201204631] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Indexed: 01/06/2023]
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64
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Krall N, Scheuermann J, Neri D. Entwicklung zielgerichteter niedermolekularer zytotoxischer Wirkstoffverbindungen mit DNA-codierten chemischen Bibliotheken. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201204631] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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65
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Abstract
Single photon emission computed tomography (SPECT) is the state-of-the-art imaging modality in nuclear medicine despite the fact that only a few new SPECT tracers have become available in the past 20 years. Critical for the future success of SPECT is the design of new and specific tracers for the detection, localization, and staging of a disease and for monitoring therapy. The utility of SPECT imaging to address oncologic questions is dependent on radiotracers that ideally exhibit excellent tissue penetration, high affinity to the tumor-associated target structure, specific uptake and retention in the malignant lesions, and rapid clearance from non-targeted tissues and organs. In general, a target-specific SPECT radiopharmaceutical can be divided into two main parts: a targeting biomolecule (e.g. peptide, antibody fragment) and a γ-radiation emitting radionuclide (e.g. (99m)Tc, (123)I). If radiometals are used as the radiation source, a bifunctional chelator is needed to link the radioisotope to the targeting entity. In a rational SPECT tracer design these single components have to be critically evaluated in order to achieve a balance among the demands for adequate target binding, and a rapid clearance of the radiotracer. The focus of this chapter is to depict recent developments of tumor-targeted SPECT radiotracers for imaging of cancer diseases. Possibilities for optimization of tracer design and potential causes for design failure are discussed and highlighted with selected examples.
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Affiliation(s)
- Cristina Müller
- Center for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen-PSI, Switzerland.
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66
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Deery E, Schroeder S, Lawrence AD, Taylor SL, Seyedarabi A, Waterman J, Wilson KS, Brown D, Geeves MA, Howard MJ, Pickersgill RW, Warren MJ. An enzyme-trap approach allows isolation of intermediates in cobalamin biosynthesis. Nat Chem Biol 2012; 8:933-40. [PMID: 23042036 PMCID: PMC3480714 DOI: 10.1038/nchembio.1086] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 09/05/2012] [Indexed: 11/16/2022]
Abstract
The biosynthesis of many vitamins and coenzymes has often proven difficult to elucidate owing to a combination of low abundance and kinetic lability of the pathway intermediates. Through a serial reconstruction of the cobalamin (vitamin B(12)) pathway in Escherichia coli and by His tagging the terminal enzyme in the reaction sequence, we have observed that many unstable intermediates can be isolated as tightly bound enzyme-product complexes. Together, these approaches have been used to extract intermediates between precorrin-4 and hydrogenobyrinic acid in their free acid form and permitted the delineation of the overall reaction catalyzed by CobL, including the formal elucidation of precorrin-7 as a metabolite. Furthermore, a substrate-carrier protein, CobE, that can also be used to stabilize some of the transient metabolic intermediates and enhance their onward transformation, has been identified. The tight association of pathway intermediates with enzymes provides evidence for a form of metabolite channeling.
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Affiliation(s)
- Evelyne Deery
- School of Biosciences, University of Kent, Canterbury, Kent, UK
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67
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Maximal load of the vitamin B12 transport system: a study on mice treated for four weeks with high-dose vitamin B12 or cobinamide. PLoS One 2012; 7:e46657. [PMID: 23049711 PMCID: PMC3462184 DOI: 10.1371/journal.pone.0046657] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Accepted: 09/05/2012] [Indexed: 12/24/2022] Open
Abstract
Several studies suggest that the vitamin B12 (B12) transport system can be used for the cellular delivery of B12-conjugated drugs, also in long-term treatment Whether this strategy will affect the endogenous metabolism of B12 is not known. To study the effect of treatment with excess B12 or an inert derivative, we established a mouse model using implanted osmotic minipumps to deliver saline, cobinamide (Cbi) (4.25 nmol/h), or B12 (1.75 nmol/h) for 27 days (n = 7 in each group). B12 content and markers of B12 metabolism were analysed in plasma, urine, kidney, liver, and salivary glands. Both Cbi and B12 treatment saturated the transcobalamin protein in mouse plasma. Cbi decreased the content of B12 in tissues to 33–50% of the level in control animals but did not influence any of the markers examined. B12 treatment increased the tissue B12 level up to 350%. In addition, the transcript levels for methylenetetrahydrofolate reductase in kidneys and for transcobalamin and transcobalamin receptor in the salivary glands were reduced. Our study confirms the feasibility of delivering drugs through the B12 transport system but emphasises that B12 status should be monitored because there is a risk of decreasing the transport of endogenous B12. This risk may lead to B12 deficiency during prolonged treatment.
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Kulcsár G, Gaál D, Kulcsár PI, Schulcz Á, Czömpöly T. A mixture of amino acids and other small molecules present in the serum suppresses the growth of murine and human tumors in vivo. Int J Cancer 2012; 132:1213-21. [PMID: 22858865 PMCID: PMC3562491 DOI: 10.1002/ijc.27756] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 07/02/2012] [Accepted: 07/09/2012] [Indexed: 11/23/2022]
Abstract
Previously we have hypothesized that the small molecules which are selectively accumulated in cancer cells might participate in a non-immunological antitumor surveillance mechanism. We demonstrated earlier that a mixture of experimentally selected substances (“active mixture”, AM: l-arginine, l-histidine, l-methionine, l-phenylalanine, l-tyrosine, l-tryptophan, l-ascorbate, d-biotin, pyridoxine, riboflavin, adenine, l(-)malate) possesses a selective toxic effect in vitro on a variety of tumor cell lines, and we have shown that the AM selectively induces apoptosis of cancer cells in vitro. To explore the in vivo significance of our earlier findings we examined the antitumor effect of AM in Colon 26 murine colorectal adenocarcinoma, B16 murine melanoma, MXT murine mammary carcinoma, S180 murine sarcoma, P388 murine lymphoid leukemia, HL-60 human promyeloid leukemia, PC-3 human prostate carcinoma, and HT-29 human colon carcinoma tumor models. Treatment of tumor bearing mice with AM inhibited the growth of the tumors investigated, with an inhibitory effect ranging from 40 to 69%. The AM had a comparable antitumor effect with 5-fluorouracil and cisplatin in the Colon-26 tumor model, and combined treatment with AM and 5-fluorouracil or cisplatin resulted in an enhanced tumor growth inhibitory effect. The AM induced apoptosis through the mitochondrial pathway and induced G1 arrest in PC-3 cells and increased the number of apoptotic cells in PC-3 xenografts. These findings suggest that the AM might offer an interesting perspective in the treatment of cancer and in combination with other treatments may offer hope for a more effective cancer therapy.
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Affiliation(s)
- Gyula Kulcsár
- Immunal Ltd., Cancer Research and Product Development Laboratory, H-7630 Pécs, Finn u. 1/1., Hungary.
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69
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Morais GR, Paulo A, Santos I. Organometallic Complexes for SPECT Imaging and/or Radionuclide Therapy. Organometallics 2012. [DOI: 10.1021/om300501d] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Goreti Ribeiro Morais
- Unidade de Ciências
Quı́micas e Radiofarmacêuticas, Instituto
Tecnológico e Nuclear, Instituto Superior Técnico, Universidade Técnica de Lisboa, Estrada Nacional
10, 2686-953, Sacavém, Portugal
| | - António Paulo
- Unidade de Ciências
Quı́micas e Radiofarmacêuticas, Instituto
Tecnológico e Nuclear, Instituto Superior Técnico, Universidade Técnica de Lisboa, Estrada Nacional
10, 2686-953, Sacavém, Portugal
| | - Isabel Santos
- Unidade de Ciências
Quı́micas e Radiofarmacêuticas, Instituto
Tecnológico e Nuclear, Instituto Superior Técnico, Universidade Técnica de Lisboa, Estrada Nacional
10, 2686-953, Sacavém, Portugal
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Furger E, Fedosov SN, Launholt Lildballe D, Waibel R, Schibli R, Nexo E, Fischer E. Comparison of recombinant human haptocorrin expressed in human embryonic kidney cells and native haptocorrin. PLoS One 2012; 7:e37421. [PMID: 22662153 PMCID: PMC3360681 DOI: 10.1371/journal.pone.0037421] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 04/20/2012] [Indexed: 02/02/2023] Open
Abstract
Haptocorrin (HC) is a circulating corrinoid binding protein with unclear function. In contrast to transcobalamin, the other transport protein in blood, HC is heavily glycosylated and binds a variety of cobalamin (Cbl) analogues. HC is present not only in blood but also in various secretions like milk, tears and saliva. No recombinant form of HC has been described so far. We report the expression of recombinant human HC (rhHC) in human embryonic kidney cells. We purified the protein with a yield of 6 mg (90 nmol) per litre of cell culture supernatant. The isolated rhHC behaved as native HC concerning its spectral properties and ability to recognize both Cbl and its baseless analogue cobinamide. Similar to native HC isolated from blood, rhHC bound to the asialoglycoprotein receptor only after removal of terminal sialic acid residues by treatment with neuraminidase. Interestingly, rhHC, that compared to native HC contains four excessive amino acids (…LVPR) at the C-terminus, showed subtle changes in the binding kinetics of Cbl, cobinamide and the fluorescent Cbl conjugate CBC. The recombinant protein has properties very similar to native HC and although showing slightly different ligand binding kinetics, rhHC is valuable for further biochemical and structural studies.
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Affiliation(s)
- Evelyne Furger
- Center for Radiopharmaceutical Sciences, Paul Scherrer Institute, Villigen, Switzerland
| | | | | | - Robert Waibel
- Center for Radiopharmaceutical Sciences, Paul Scherrer Institute, Villigen, Switzerland
| | - Roger Schibli
- Center for Radiopharmaceutical Sciences, Paul Scherrer Institute, Villigen, Switzerland
| | - Ebba Nexo
- Department of Clinical Biochemistry, Aarhus University Hospital, Aarhus, Denmark
| | - Eliane Fischer
- Center for Radiopharmaceutical Sciences, Paul Scherrer Institute, Villigen, Switzerland
- * E-mail:
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71
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Thirupathaiah Y, Swarupa Rani C, Sudhakara Reddy M, Venkateswar Rao L. Effect of chemical and microbial vitamin B₁₂ analogues on production of vitamin B₁₂. World J Microbiol Biotechnol 2012; 28:2267-71. [PMID: 22806050 DOI: 10.1007/s11274-012-1011-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2011] [Accepted: 01/28/2012] [Indexed: 10/14/2022]
Abstract
Strain improvement by genetic manipulation or optimization of fermentation conditions for overproduction of vitamin B(12) has a drawback due to feed back inhibition. To resist the feed back inhibition by analogues of vitamin B(12) in Propionibacterium freudenrechii subsps. shermanii (OLP-5), we have tested with microbially separated B(12) analogues from three different strains. Microbial analogues were differentiated from commercially available vitamin B(12) by high pressure liquid chromatography and spectrophotometric method. An analogue isolated from NRRL-B-4327 was shown to increase vitamin B(12) concentration from 18.53 ± 0.15 to 31.67 ± 0.58 mg/l in OLP-5 strain. The presence of chemical analogue (ICH(2) Co(DH)(2) (H(2)Py)(4)) increased vitamin B(12) production from 16.13 ± 0.15 to 18.53 ± 0.15 mg/l in OLP-5. These findings revealed that addition of B(12) analogues in fermentation media have developed strain resistance to feed back inhibition by vitamin B(12).
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Affiliation(s)
- Yeruva Thirupathaiah
- Department of Microbiology, Osmania University, Hyderabad 500007, Andhra Pradesh, India
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72
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Russell-Jones. Increasing the Tumoricidal Activity of Daunomycin-pHPMA Conjugates Using Vitamin B12 as a Targeting Agent. ACTA ACUST UNITED AC 2012. [DOI: 10.6000/1929-2279.2012.01.02.6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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73
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Liu Y, Wang B, Liu X, Xie X, Gu W, Li H, Cao X. Clinical variations of serum levels of ferritin, folic acid and vitamin B12 in acute leukemia patients. ACTA ACUST UNITED AC 2011. [DOI: 10.1016/s1000-1948(11)60051-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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74
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Fedosov SN, Ruetz M, Gruber K, Fedosova NU, Kräutler B. A Blue Corrinoid from Partial Degradation of Vitamin B12 in Aqueous Bicarbonate: Spectra, Structure, and Interaction with Proteins of B12 Transport. Biochemistry 2011; 50:8090-101. [DOI: 10.1021/bi200724s] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sergey N. Fedosov
- Department of Molecular Biology
and Genetics, Aarhus University, Science
Park, Gustav Wieds Vej 10, DK 8000 Aarhus C, Denmark
| | - Markus Ruetz
- Institute of Organic Chemistry
and Center of Molecular Biosciences, University of Innsbruck, Innrain 52A, Innsbruck A-6020, Austria
| | - Karl Gruber
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/3, Graz A-8010,
Austria
| | - Natalya U. Fedosova
- Department of Biomedicine, Aarhus University, Ole Worms Alle 1185, DK 8000 Aarhus
C, Denmark
| | - Bernhard Kräutler
- Institute of Organic Chemistry
and Center of Molecular Biosciences, University of Innsbruck, Innrain 52A, Innsbruck A-6020, Austria
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75
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Todorova R. Comparative analysis of the methods of drug and protein delivery for the treatment of cancer, genetic diseases and diagnostics. Drug Deliv 2011; 18:586-98. [DOI: 10.3109/10717544.2011.600783] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
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76
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Núñez-Montenegro A, Carballo R, Hermida-Ramón JM, Vázquez-López EM. Synthesis, characterization, reactivity and computational studies of new rhenium(I) complexes with thiosemicarbazone ligands derived from 4-(methylthio)benzaldehyde. Polyhedron 2011. [DOI: 10.1016/j.poly.2011.05.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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77
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Keratin 15, transcobalamin I and homeobox gene Hox-B13 expression in breast phyllodes tumors: novel markers in biological classification. Breast Cancer Res Treat 2011; 132:143-51. [DOI: 10.1007/s10549-011-1555-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 04/25/2011] [Indexed: 01/10/2023]
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78
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Huang Y, Zhao R, Fu Y, Zhang Q, Xiong S, Li L, Zhou R, Liu G, Chen Y. Highly Specific Targeting and Imaging of Live Cancer Cells by Using a Peptide Probe Developed from Rationally Designed Peptides. Chembiochem 2011; 12:1209-15. [DOI: 10.1002/cbic.201100031] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Indexed: 02/06/2023]
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79
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Clardy SM, Allis DG, Fairchild TJ, Doyle RP. Vitamin B12in drug delivery: breaking through the barriers to a B12bioconjugate pharmaceutical. Expert Opin Drug Deliv 2010; 8:127-40. [DOI: 10.1517/17425247.2011.539200] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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80
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Ruiz-Sánchez P, König C, Ferrari S, Alberto R. Vitamin B12 as a carrier for targeted platinum delivery: in vitro cytotoxicity and mechanistic studies. J Biol Inorg Chem 2010; 16:33-44. [DOI: 10.1007/s00775-010-0697-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Accepted: 07/30/2010] [Indexed: 01/06/2023]
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81
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Collin SM, Metcalfe C, Refsum H, Lewis SJ, Zuccolo L, Smith GD, Chen L, Harris R, Davis M, Marsden G, Johnston C, Lane JA, Ebbing M, Bønaa KH, Nygård O, Ueland PM, Grau MV, Baron JA, Donovan JL, Neal DE, Hamdy FC, Smith AD, Martin RM. Circulating folate, vitamin B12, homocysteine, vitamin B12 transport proteins, and risk of prostate cancer: a case-control study, systematic review, and meta-analysis. Cancer Epidemiol Biomarkers Prev 2010; 19:1632-42. [PMID: 20501771 DOI: 10.1158/1055-9965.epi-10-0180] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Disturbed folate metabolism is associated with an increased risk of some cancers. Our objective was to determine whether blood levels of folate, vitamin B(12), and related metabolites were associated with prostate cancer risk. METHODS Matched case-control study nested within the U.K. population-based Prostate testing for cancer and Treatment (ProtecT) study of prostate-specific antigen-detected prostate cancer in men ages 50 to 69 years. Plasma concentrations of folate, B(12) (cobalamin), holo-haptocorrin, holo-transcobalamin total transcobalamin, and total homocysteine (tHcy) were measured in 1,461 cases and 1,507 controls. ProtecT study estimates for associations of folate, B(12), and tHcy with prostate cancer risk were included in a meta-analysis, based on a systematic review. RESULTS In the ProtecT study, increased B(12) and holo-haptocorrin concentrations showed positive associations with prostate cancer risk [highest versus lowest quartile of B(12) odds ratio (OR) = 1.17 (95% confidence interval, 0.95-1.43); P(trend) = 0.06; highest versus lowest quartile of holo-haptocorrin OR = 1.27 (1.04-1.56); P(trend) = 0.01]; folate, holo-transcobalamin, and tHcy were not associated with prostate cancer risk. In the meta-analysis, circulating B(12) levels were associated with an increased prostate cancer risk [pooled OR = 1.10 (1.01-1.19) per 100 pmol/L increase in B(12); P = 0.002]; the pooled OR for the association of folate with prostate cancer was positive [OR = 1.11 (0.96-1.28) per 10 nmol/L; P = 0.2) and conventionally statistically significant if ProtecT (the only case-control study) was excluded [OR = 1.18 (1.00-1.40) per 10 nmol/L; P = 0.02]. CONCLUSION Vitamin B(12) and (in cohort studies) folate were associated with increased prostate cancer risk. IMPACT Given current controversies over mandatory fortification, further research is needed to determine whether these are causal associations.
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Affiliation(s)
- Simon M Collin
- Department of Social Medicine, University of Bristol, Bristol, United Kingdom.
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82
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Randaccio L, Geremia S, Demitri N, Wuerges J. Vitamin B12: unique metalorganic compounds and the most complex vitamins. Molecules 2010; 15:3228-59. [PMID: 20657474 PMCID: PMC6257451 DOI: 10.3390/molecules15053228] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 04/27/2010] [Accepted: 04/28/2010] [Indexed: 11/16/2022] Open
Abstract
The chemistry and biochemistry of the vitamin B(12) compounds (cobalamins, XCbl) are described, with particular emphasis on their structural aspects and their relationships with properties and function. A brief history of B(12), reveals how much the effort of chemists, biochemists and crystallographers have contributed in the past to understand the basic properties of this very complex vitamin. The properties of the two cobalamins, the two important B(12) cofactors Ado- and MeCbl are described, with particular emphasis on how the Co-C bond cleavage is involved in the enzymatic mechanisms. The main structural features of cobalamins are described, with particular reference to the axial fragment. The structure/property relationships in cobalamins are summarized. The recent studies on base-off/base-on equilibrium are emphasized for their relevance to the mode of binding of the cofactor to the protein scaffold. The absorption, transport and cellular uptake of cobalamins and the structure of the B(12) transport proteins, IF and TC, in mammals are reviewed. The B(12) transport in bacteria and the structure of the so far determined proteins are briefly described. The currently accepted mechanisms for the catalytic cycles of the AdoCbl and MeCbl enzymes are reported. The structure and function of B(12) enzymes, particularly the important mammalian enzymes methyltransferase (MetH) and methyl-malonyl-coenzyme A mutase (MMCM), are described and briefly discussed. Since fast proliferating cells require higher amount of vitamin B(12) than that required by normal cells, the study of B(12 )conjugates as targeting agents has recently gained importance. Bioconjugates have been studied as potential agents for delivering radioisotopes and NMR probes or as various cytotoxic agents towards cancer cells in humans and the most recent studies are described. Specifically, functionalized bioconjugates are used as "Trojan horses" to carry into the cell the appropriate antitumour or diagnostic label. Possible future developments of B(12) work are summarized.
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Affiliation(s)
- Lucio Randaccio
- Centre of Excellence in Biocrystallography, Department of Chemical Sciences, University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy.
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83
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Johansson EMV, Dubois J, Darbre T, Reymond JL. Glycopeptide dendrimer colchicine conjugates targeting cancer cells. Bioorg Med Chem 2010; 18:6589-97. [PMID: 20674369 DOI: 10.1016/j.bmc.2010.04.026] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 03/15/2010] [Accepted: 04/07/2010] [Indexed: 02/08/2023]
Abstract
Screening of a 65,536-member one-bead-one-compound (OBOC) combinatorial library of glycopeptide dendrimers of structure ((betaGal)(n)(+1)X(8)X(7)X(6)X(5))(2)DapX(4)X(3)X(2)X(1)(beta-Gal)(m) (betaGal=beta-galactosyl-thiopropionic acid, X(8-1)=variable amino acids, Dap=l-2,3-diaminopropionic acid, n, m=0, or 1 if X(8)=Lys resp. X(1)=Lys) for binding of Jurkat cells to the library beads in cell culture, resynthesis and testing lead to the identification of dendrimer J1 (betaGal-Gly-Arg-His-Ala)(2)Dap-Thr-Arg-His-Asp-CysNH(2) and related analogues as delivery vehicles. Cell targeting is evidenced by FACS with fluorescein conjugates such as J1F. The colchicine conjugate J1C is cytotoxic with LD(50)=1.5 microM. The beta-galactoside groups are necessary for activity, as evidenced by the absence of cell-binding and cytotoxicity in the non-galactosylated, acetylated analogue AcJ1F and AcJ1C, respectively. The pentagalactosylated dendrimer J4 betaGal(4)(Lys-Arg-His-Leu)(2)Dap-Thr-Tyr-His-Lys(betaGal)-Cys) selectively labels Jurkat cell as the fluorescein derivative J4F, but its colchicine conjugate J4C lacks cytotoxicity. Tubulin binding assays show that the colchicine dendrimer conjugates do not bind to tubulin, implying intracellular degradation of the dendrimers releasing the active drug.
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Affiliation(s)
- Emma M V Johansson
- Department of Chemistry and Biochemistry, University of Berne, Freiestrasse 3, CH-3012 Berne, Switzerland
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84
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85
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Núñez-Montenegro A, Carballo R, Vázquez-López EM. Synthesis and characterization of thiosemicarbazone derivatives of 2-chloro-4-hydroxy-benzaldehyde and their rhenium(I) complexes. Polyhedron 2009. [DOI: 10.1016/j.poly.2009.09.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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86
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Quadros EV. Advances in the understanding of cobalamin assimilation and metabolism. Br J Haematol 2009; 148:195-204. [PMID: 19832808 DOI: 10.1111/j.1365-2141.2009.07937.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The haematological and neurological consequences of cobalamin deficiency define the essential role of this vitamin in key metabolic reactions. The identification of cubilin-amnionless as the receptors for intestinal absorption of intrinsic factor-bound cobalamin and the plasma membrane receptor for cellular uptake of transcobalamin bound cobalamin have provided a clearer understanding of the absorption and cellular uptake of this vitamin. As the genes involved in the intracellular processing of cobalamins and genetic defects of these pathways are identified, the metabolic disposition of cobalamins and the proteins involved are being recognized. The synthesis of methylcobalamin and 5'-deoxyadenosylcobalamin, their utilization in conjunction with methionine synthase and methylmalonylCoA mutase, respectively, and the metabolic consequences of defects in these pathways could provide insights into the clinical presentation of cobalamin deficiency.
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Affiliation(s)
- Edward V Quadros
- Department of Medicine, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA.
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87
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Siega P, Wuerges J, Arena F, Gianolio E, Fedosov SN, Dreos R, Geremia S, Aime S, Randaccio L. Release of toxic Gd3+ ions to tumour cells by vitamin B12 bioconjugates. Chemistry 2009; 15:7980-7989. [PMID: 19562781 DOI: 10.1002/chem.200802680] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Two probes consisting of vitamin B(12) (CNCbl) conjugated to Gd chelates by esterification of the ribose 5'-OH moiety, Gd-DTPA-CNCbl (1; DTPA = diethylenetriamine-N,N,N',N'',N''-pentaacetic acid) and Gd-TTHA-CNCbl (2; TTHA = triethylenetetramine-N,N,N',N'',N''',N'''-hexaacetic acid), have been synthesised and characterised. The crystal structure of a dimeric form of 1, obtained by crystallisation with an excess of GdCl(3), has been determined. The kinetics of binding to and dissociation from transcobalamin II show that 1 and 2 maintain high-affinity binding to the vitamin B(12) transport protein. Complex 2 is very stable with respect to Gd(3+) release owing to the saturated co-ordination of the Gd(3+) ion by four amino and five carboxylate groups. Hydrolysis of the ester functionality occurs on the time scale of several hours. The lack of saturation and the possible involvement of the ester functionality in co-ordination result in lower stability of 1 towards hydrolysis and in a considerable release of Gd(3+) in vitro. Gd(3+) ions released from 1 are avidly taken up by the K562 tumour cells to an extent corresponding to approximately 10(10) Gd(3+) per cell. The internalisation of toxic Gd(3+) ions causes a marked decrease in cell viability as assessed by Trypan blue and WST-1 tests. On the contrary, the experiments with the more stable 2 did not show any significant cell internalisation of Gd(3+) ions and any influence on cell viability. The results point to new avenues of in situ generation of cytotoxic pathways based on the release of toxic Gd(3+) ions by vitamin B(12) bioconjugates.
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Affiliation(s)
- Patrizia Siega
- Department of Chemical Sciences, Centre of Excellence in Biocrystallography, University of Trieste, Via Licio Giorgieri 1, 32127 Trieste, Italy
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88
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Saatchi K, Häfeli UO. Radiolabeling of Biodegradable Polymeric Microspheres with [99mTc(CO)3]+ and in Vivo Biodistribution Evaluation using MicroSPECT/CT Imaging. Bioconjug Chem 2009; 20:1209-17. [DOI: 10.1021/bc900066j] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Katayoun Saatchi
- Faculty of Pharmaceutical Sciences, University of British Columbia, 2146 East Mall, Vancouver, BC V6T 1Z3, Canada
| | - Urs O. Häfeli
- Faculty of Pharmaceutical Sciences, University of British Columbia, 2146 East Mall, Vancouver, BC V6T 1Z3, Canada
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89
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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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90
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A critical quantum chemical and experimental study of the potentiality of direct labeling of the CN group with [99mTc(CO)3]+ or [186/188Re(CO)3]+ in CN containing biomolecules. Nucl Med Biol 2008; 35:747-53. [DOI: 10.1016/j.nucmedbio.2008.06.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2008] [Revised: 06/13/2008] [Accepted: 06/19/2008] [Indexed: 10/21/2022]
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91
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Mindt TL, Müller C, Melis M, de Jong M, Schibli R. "Click-to-chelate": in vitro and in vivo comparison of a 99mTc(CO)3-labeled N(tau)-histidine folate derivative with its isostructural, clicked 1,2,3-triazole analogue. Bioconjug Chem 2008; 19:1689-95. [PMID: 18646835 DOI: 10.1021/bc800183r] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A side-by-side comparison of the synthesis, radiolabeling, and in vitro and in vivo characterization of two new and isostructural (99m)Tc-tricarbonyl folic acid radiotracers comprising either a N(tau)-functionalized histidine (His) chelator or a 1,4-bifunctionalized 1,2,3-triazole His analogue is described. The 1,2,3-triazole-containing folic acid derivative was synthesized in approximately 80% yield by a short reaction sequence including application of click chemistry (the Cu(I)-catalyzed cycloaddition of azides and terminal alkynes). The synthesis of the ligand system and the functionalization of the folic acid derivative were accomplished simultaneously, which prompted us to call this approach "click-to-chelate". In comparison, the reported regioselective synthesis of the N(tau)-His compound provided the final product in only very low yields (<1%). While the efficiency of the syntheses differs considerably, the two isostructural folate derivatives exhibit virtually identical properties with respect to Tc-99m radiolabeling and in vitro and in vivo characteristics as shown by experiments performed with FR-positive KB cells and xenografted mice bearing folate receptor overexpressing tumors. We have demonstrated herein for the first time that a ligand system known to be an excellent chelator for the stable complexation of the organometallic core [M(CO)3] (+) (M = Tc-99m, Re) can be replaced by an isostructural 1,2,3-triazole analogue without influencing the characteristics of the radiometal conjugate. The "click-to-chelate" strategy provides a highly efficient and convenient entry to metal conjugates suitable for diagnostic and potentially therapeutic applications. The described procedures should be readily applicable to any azide-functionalized (bio)molecule and, thus, are likely to represent the method of choice for the future development of radiopharmaceuticals radiolabeled with the organometallic precursors [M(CO)3(H2O)3] (+) (M = (99m)Tc, (188)Re).
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Affiliation(s)
- Thomas L Mindt
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
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