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001-es BibID:	BIBFORM078703
Első szerző:	Vágner Adrienn (vegyész, kémikus)
Cím:	Equilibrium Thermodynamics, Formation, and Dissociation Kinetics of Trivalent Iron and Gallium Complexes of Triazacyclononane-Triphosphinate (TRAP) Chelators: Unraveling the Foundations of Highly Selective Ga-68 Labeling / Adrienn Vágner, Attila Forgács, Ernő Brücher, Imre Tóth, Alessandro Maiocchi, Alexander Wurzer, Hans-Jürgen Wester, Johannes Notni, Zsolt Baranyai
Dátum:	2018
ISSN:	2296-2646
Megjegyzések:	In order to rationalize the influence of FeIII contamination on labeling with the 68Ga eluted from 68Ge/68Ga-generator, a detailed investigation was carried out on the equilibrium properties, formation and dissociation kinetics of GaIII- and FeIII - complexes of 1,4,7-triazacyclononane-1,4,7-tris(methylene[2-carboxyethylphosphinic acid]) (H6TRAP). The stability and protonation constants of the [Fe(TRAP)]3? complex were determined by pH-potentiometry and spectrophotometry by following the competition reaction between the TRAP ligand and benzhydroxamic acid (0.15 M NaNO3, 25?C). The formation rates of [Fe(TRAP)] and [Ga(TRAP)] complexes were determined by spectrophotometry and 31P-NMR spectroscopy in the pH range 4.5? 6.5 in the presence of 5?40 fold HxTRAP(x?6) excess (x = 1 and 2, 0.15 M NaNO3, 25?C). The kinetic inertness of [Fe(TRAP)]3? and [Ga(TRAP)]3? was examined by the trans-chelation reactions with 10 to 20-fold excess of HxHBED(x?4) ligand by spectrophotometry at 25?C in 0.15 M NaCl (x = 0,1 and 2). The stability constant of [Fe(TRAP)]3? (logKFeL = 26.7) is very similar to that of [Ga(TRAP)]3? (logKGaL = 26.2). The rates of ligand exchange reaction of [Fe(TRAP)]3? and [Ga(TRAP)]3? with HxHBED(x?4) are similar. The reactions take place quite slowly via spontaneous dissociation of [M(TRAP)]3?, [M(TRAP)OH]4? and [M(TRAP)(OH)2] 5? species. Dissociation half-lives (t1/2) of [Fe(TRAP)]3? and [Ga(TRAP)]3? complexes are 1.1 ? 105 and 1.4 ? 105 h at pH = 7.4 and 25?C. The formation reactions of [Fe(TRAP)]3? and [Ga(TRAP)]3? are also slow due to the formation of the unusually stable monoprotonated [?M(HTRAP)]2? intermediates [?logKGa(HL) = 10.4 and ?logKFe(HL) = 9.9], which are much more stable than the [?Ga(HNOTA)]+ intermediate [?logKGa(HL) = 4.2]. Deprotonation and transformation of the monoprotonated [?(HTRAP)]2? intermediates into the final complex occur via OH?-assisted reactions. Rate constants (kOH) characterizing the OH?-driven deprotonation and transformation of [? Ga(HTRAP)]2? and [?Fe(HTRAP)]2? intermediates are 1.4 ? 105 M?1 s-1 and 3.4 ? 104 ?1s?1, respectively. In conclusion, the equilibrium and kinetic properties of [Fe(TRAP)] and [Ga(TRAP)] complexes are remarkably similar due to the close physico-chemical properties of FeIII and GaIII-ions. However, a slightly faster formation of [Ga(TRAP)] over [Fe(TRAP)] provides a rationale for a previously observed, selective complexation of 68GaIII in presence of excess FeIII.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban chelates gallium iron thermodynamics kinetics reaction mechanism positron emission tomography
Megjelenés:	Frontiers in Chemistry. - 6 (2018), p. 1-12. -
További szerzők:	Forgács Attila (1988-) (vegyész) Brücher Ernő (1935-) (vegyész) Tóth Imre (1950-) (vegyész) Maiocchi, Alessandro (vegyész) Wurzer, Alexander Wester, Hans J. Notni, Johannes Baranyai Zsolt (1977-) (vegyész)
Pályázati támogatás:	GINOP-2.3.3-15-2016-00004 GINOP GINOP-2.3.2-15-2016-00008 GINOP
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001-es BibID:	BIBFORM112815
035-os BibID:	(WoS)001025780100001 (Scopus)85165479537
Első szerző:	Váradi Balázs (vegyész)
Cím:	Synthesis and characterization of a novel [52Mn]Mn-labelled affibody based radiotracer for HER2+ targeting / Balázs Váradi, Károly Brezovcsik, Zoltán Garda, Eniko Madarasi, Horea Szedlacsek, Rodica-Aura Badea, Andrei-Mihai Vasilescu, Adina-Gabriela Puiu, Aura Ionescu, Livia-Elena Sima, Cristian V. A. Munteanu, Simona Cǎlǎraş, Adrienn Vagner, Dezső Szikra, Ngô Minh Toàn, Tibor Nagy, Zoltán Szűcs, Stefan Eugen Szedlacsek, Gabor Nagy, Gyula Tircsó
Dátum:	2023
ISSN:	2052-1545 2052-1553
Megjegyzések:	Targeted molecular imaging is a valuable tool in cancer diagnosis. The palette of manganese isotopes provides an excellent opportunity for bimodal imaging, given that it possesses a long-lived positron-emitting isotope usable in functional Positron Emission Tomography (PET) imaging (52Mn), while the paramagnetic nature of 55Mn makes monoaquated complexes of Mn(II) suitable for magnetic Resonance Imaging (MRI). The present study aims to synthesize new model bifunctional Mn(II) chelators (BFC) derived from the macrocyclic 3,9-PC2A ligand and to test their physicochemical properties. From these 3,9-PC2ABnpCO2H platform was selected for bioconjugation and for further in vivo studies. Anti-HER2 affibody was used as a highly specific binding protein. It was expressed in a prokaryotic system, purified by affinity chromatography followed by RP-HPLC. The specificity of the affibody for HER2 receptors was proved following its conjugation with AlexaFluor555 dye. Finally the affibody was conjugated with the selected 3,9-PC2ABnpCO2H BFC and [52Mn]Mn(II) labelling was performed. The labelled conjugate was tested in vivo by PET imaging using MDA-MB (HER2+) and 4T1 (HER2-) tumour-bearing mice. The results demonstrate that the [[52Mn]Mn(3,9 PC2ABnpMA)(H2O)]-Cys-HER2-affibody conjugate is an efficient and specific molecular vehicle for targeting and visualizing HER2+ tumours by 52Mn-based PET imaging.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk
Megjelenés:	Inorganic Chemistry Frontiers. - 10 : 16 (2023), p. 4734-4745. -
További szerzők:	Brezovcsik Károly (1990-) (vegyész) Garda Zoltán (1989-) (vegyész) Madarasi Enikő Szedlacsek, Horea Badea, Rodica-Aura Vasilescu, Andrei-Mihai Puiu, Adina-Gabriela Ionescu, Aura Elena Sima, Livia-Elena Munteanu, Cristian V. A. Cǎlǎraş, Simona Vágner Adrienn (1990-) (vegyész, kémikus) Szikra Dezső Péter (1983-) (vegyész) Toàn, Ngô Minh Nagy Tibor (1988-) (vegyész) Szűcs Zoltán Szedlacsek, Stefan Eugen Nagy Gábor (1990-) (radiokémikus, vegyész) Tircsó Gyula (1977-) (vegyész, kémia tanár)
Pályázati támogatás:	NKFIH-K-128201 Egyéb NKFIH-134694 Egyéb Doctoral School of Chemistry at the University of Debrecen Egyéb Gedeon Richter's Talentum Foundation established by Gedeon Richter Plc (Gedeon Richter Ph.D. Fellowship) Egyéb Doctoral Student Scholarship Program of the Cooperative Doctoral Program of the Ministry of Innovation and Technology financed by the National Research, Development, and Innovation Fund (NKFIH) Egyéb TKP2021-NKTA-42 Egyéb Romanian Ministry of Education and Research, CCDI - UEFISCDI, project number: PN-III-P2-2.1-PED-2019-4184, within PNCDI III, acronym NARAD; PN-III-P1-1.2-PCCDI-2017-0737, within PNCDI III, acronym ARTEMIS; PN-III-P1-1.2-PCCDI-2017-0769, within PNCDI III, acronym ONCORAD Egyéb The Romanian Academy and the Hungarian Academy of Sciences through the bilateral collaboration agreement no. 3698 of 13.09.2018 "Mobility projects" Egyéb
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001-es BibID:	BIBFORM076233
Első szerző:	Wurzer, Alexander
Cím:	Synthesis of Symmetrical Tetrameric Conjugates of the Radiolanthanide Chelator DOTPI for Application in Endoradiotherapy by Means of Click Chemistry / Alexander Wurzer, Adrienn Vágner, Dávid Horváth, Flóra Fellegi, Hans-Jürgen Wester, Ferenc K. Kálmán, Johannes Notni
Dátum:	2018
ISSN:	2296-2646
Megjegyzések:	Due to its 4 carbonic acid groups being available for bioconjugation, the cyclen tetraphosphinate chelator DOTPI, 1,4,7,10-tetraazacyclododecane-1,4,7, 10-tetrakis[methylene(2-carboxyethylphosphinic acid)], represents an ideal scaffold for synthesis of tetrameric bioconjugates for labeling with radiolanthanides, to be applied as endoradiotherapeuticals. We optimized a protocol for bio-orthogonal DOTPI conjugation via Cu(I)-catalyzed Huisgen-cycloaddition of terminal azides and alkynes (CuAAC), based on the building block DOTPI(azide)4. A detailed investigation of kinetic properties of Cu(II)-DOTPI complexes aimed at optimization of removal of DOTPI-bound copper by transchelation. Protonation and equilibrium properties of Ca(II)-, Zn(II), and Cu(II)-complexes of DOTPI and its tetra-cyclohexylamide DOTPI(Chx)4 (a model for DOTPI conjugates) as well as kinetic inertness (transchelation challenge in the presence of 20 to 40-fold excess of EDTA) were investigated by pH-potentiometry and spectrophotometry. Similar stability constants of CaII-, ZnII, and CuII-complexes of DOTPI (logK(CaL) = 8.65, logK(ZnL = 15.40, logK(CuL) = 20.30) and DOTPI(Chx)4 (logK(CaL) = 8.99, logK(ZnL) = 15.13, logK(CuL) = 20.42) were found. Transchelation of Cu(II)-complexes occurs via proton-assisted dissociation, whereafter released Cu(II) is scavenged by EDTA. The corresponding dissociation rates [kd = 25 ? 10?7 and 5 ? 10?7 s?1 for Cu(DOTPI) and Cu(DOTPI(Chx)4), respectively, at pH 4 and 298 K] indicate that conjugation increases the kinetic inertness by a factor of 5. However, demetallation is completed within 4.5 and 7.2 h at pH 2 and 25?C, respectively, indicating that Cu(II) removal after formation of CuAAC can be achieved in an uncomplicated manner by addition of excess H4EDTA. For proof-of-principle, tetrameric DOTPI conjugates of the prostate-specific membrane antigen (PSMA) targeting motif Lys-urea-Glu (KuE) were synthesized via CuAAC as well as dibenzo-azacyclooctine (DBCO) based, strain-promoted click chemistry (SPAAC), which were labeled with Lu-177 and subsequently evaluated in vitro and in SCID mice bearing subcutaneous LNCaP tumor (PSMA+ human prostate carcinoma) xenografts. High affinities (3.4 and 1.4 nM, respectively) and persistent tumor uptakes (approx. 3.5% 24 h after injection) confirm suitability of DOTPI-based tetramers for application in targeted radionuclide therapy.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Frontiers in Chemistry. - 6 (2018), p. 1-11. -
További szerzők:	Vágner Adrienn (1990-) (vegyész, kémikus) Horváth Dávid (1991-) (vegyész) Fellegi Flóra Wester, Hans J. Kálmán Ferenc K. (1978-) (vegyész) Notni, Johannes
Pályázati támogatás:	GINOP-2.3.2-15-2016-00008 GINOP GINOP-2.3.3-15-2016-00004 GINOP Bolyai János Kutatási Ösztöndíj Egyéb
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