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Afzal M, Alarifi A, Abduh NAY, Ayub A, Muddassir M. Identification of anti-cancer organometallic compounds by inhibition of BCL-2/Bax interactions. Comput Biol Med 2023; 167:107657. [PMID: 37931525 DOI: 10.1016/j.compbiomed.2023.107657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 10/21/2023] [Accepted: 10/31/2023] [Indexed: 11/08/2023]
Abstract
Apoptosis is regulated by the BCL-2 family, which includes the anti-apoptotic and pro-apoptotic proteins (Bax, Bok, Bak, etc.). These proteins often interact in dimers and act as apoptotic switches. Anti-apoptotic proteins, such as BCL-2, block the functions of these pro-apoptotic proteins. The pro-apoptotic and anti-apoptotic protein-protein interactions must be inhibited to prevent tumor cells from escaping apoptosis. This method has been used to develop anticancer drugs by inhibiting BCL-2 with both natural and synthetic compounds. Metal-containing compounds were used as pharmaceuticals for human cancer patients for a long time, and cisplatin was the first candidate of this class. Drug design, however, needs to pay more attention to metal complexes. We have studied the X-ray crystal structure of the BCL-2 protein in detail and identified the hydrophobic nature of the site with two less solvent-accessible sites. Based on the hydrophobic nature of the compounds, 74 organometallic compounds with X-ray crystallographically characterized bioactivity (including anticancer activity) were selected from the Cambridge crystallographic database. For testing, molecular docking was used to determine which compound was most effective against the BCL-2 protein. Organometallic compounds (benzene)-chloro-(1-{[(9H-fluoren-2-yl)imino]methyl}naphthalen-2-olato)-ruthenium (2), (1-((1,1'-biphenyl)-4-yl)-2,3,4,5-tetramethylcyclopentadienyl)-chloro-(4,4'-dimethyl-2,2'-bipyridine)-rhodium hexafluorophosphate (37), (μ-1,1'-(butane-1,4-diyl)bis(3-oxy-2-methylpyridin-4(1H)-one))-dichloro-bis(pentamethyl-cyclopentadienyl)-di-rhodium tetrahydrate (46), (μ-1,1'-(butane-1,4-diyl)bis(3-oxy-2-methylpyridin-4(1H)-one))-dichloro-bis(pentamethyl-cyclopentadienyl)-di-iridium (47) etc are found to be important compounds in this study. The capability of different types of complex interactions was identified using Hirshfeld surface analysis of the complexes. A NCI plot was conducted to understand the nature of the interaction between complex amino acids and active-site amino acids. A DFT study was conducted to examine the stability and chemical reactivity of the selected complexes. Using this study, one suitable hydrophobic lead anti-cancer organometallic pharmaceutical was found that binds at the less solvent-accessible hydrophobic site of BCL-2.
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Affiliation(s)
- Mohd Afzal
- Department of Chemistry, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia.
| | - Abdullah Alarifi
- Department of Chemistry, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia
| | - Naaser A Y Abduh
- Department of Chemistry, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia
| | - Arusha Ayub
- Department of Medicine and Health Sciences, University of Georgia, P.O. Box-0171, Tbilisi, Georgia
| | - Mohd Muddassir
- Department of Chemistry, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia
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Łomzik M, Błauż A, Głodek M, Makal A, Tchoń D, Ayine-Tora DM, Hartinger C, Rychlik B, Plażuk D. Organometallic Ru, Os, Rh and Ir half-sandwich conjugates of ispinesib - impact of the organometallic group on the antimitotic activity. Dalton Trans 2023; 52:11859-11874. [PMID: 37464882 DOI: 10.1039/d3dt01217d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
Antimitotic agents are among the most important drugs used in anticancer therapy. Kinesin spindle protein (KSP) was proposed as a promising target for new antimitotic drugs. Herein, we report the synthesis of Ru, Os, Rh, and Ir half-sandwich complexes with the KSP inhibitor ispinesib and its (S)-enantiomer. Conjugation of the organometallic moiety with ispinesib and its (S)-enantiomer resulted in a significantly increased cytotoxicity of up to 5.6-fold compared to the parent compounds, with IC50 values in the nanomolar range. The most active derivatives were the ispinesib Ru and Rh conjugates which were able to generate reactive oxygen species (ROS), which may at least partially explain their high cytotoxicity. At the same time, the Os and Ir derivatives acted as KSP inhibitors with no effects on ROS generation.
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Affiliation(s)
- Michał Łomzik
- Department of Organic Chemistry, Faculty of Chemistry, University of Lodz, ul. Tamka 12, 91-403 Łódź, Poland.
| | - Andrzej Błauż
- Cytometry Lab, Department of Oncobiology and Epigenetics, Faculty of Biology and Environmental Protection, University of Lodz, ul. Pomorska 141/143, 90-236 Łódź, Poland
| | - Marta Głodek
- Department of Organic Chemistry, Faculty of Chemistry, University of Lodz, ul. Tamka 12, 91-403 Łódź, Poland.
| | - Anna Makal
- Laboratory for Structural and Biochemical Research (LBSBio), Biological and Chemical Research Centre, Department of Chemistry, University of Warsaw, ul. Zwirki i Wigury 101, 02-089 Warszawa, Poland
| | - Daniel Tchoń
- Laboratory for Structural and Biochemical Research (LBSBio), Biological and Chemical Research Centre, Department of Chemistry, University of Warsaw, ul. Zwirki i Wigury 101, 02-089 Warszawa, Poland
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | | | - Christian Hartinger
- School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Błażej Rychlik
- Cytometry Lab, Department of Oncobiology and Epigenetics, Faculty of Biology and Environmental Protection, University of Lodz, ul. Pomorska 141/143, 90-236 Łódź, Poland
| | - Damian Plażuk
- Department of Organic Chemistry, Faculty of Chemistry, University of Lodz, ul. Tamka 12, 91-403 Łódź, Poland.
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Bíró L, Tóth B, Lihi N, Farkas E, Buglyó P. Interaction between [(η 6- p-cym)M(H 2O) 3] 2+ (M II = Ru, Os) or [(η 5-Cp*)M(H 2O) 3] 2+ (M III = Rh, Ir) and Phosphonate Derivatives of Iminodiacetic Acid: A Solution Equilibrium and DFT Study. Molecules 2023; 28:molecules28031477. [PMID: 36771142 PMCID: PMC9918899 DOI: 10.3390/molecules28031477] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/29/2023] [Accepted: 01/31/2023] [Indexed: 02/05/2023] Open
Abstract
The pH-dependent binding strengths and modes of the organometallic [(η6-p-cym)M(H2O)3]2+ (MII = Ru, Os; p-cym = 1-methyl-4-isopropylbenzene) or [(η5-Cp*)M(H2O)3]2+ (MIII = Rh, Ir; Cp* = pentamethylcyclopentadienyl anion) cations towards iminodiacetic acid (H2Ida) and its biorelevant mono- and diphosphonate derivatives N-(phosphonomethyl)-glycine (H3IdaP) and iminodi(methylphosphonic acid) (H4Ida2P) was studied in an aqueous solution. The results showed that all three of the ligands form 1:1 complexes via the tridentate (O,N,O) donor set, for which the binding mode was further corroborated by the DFT method. Although with IdaP3- and Ida2P4- in mono- and bis-protonated species, where H+ might also be located at the non-coordinating N atom, the theoretical calculations revealed the protonation of the phosphonate group(s) and the tridentate coordination of the phosphonate ligands. The replacement of one carboxylate in Ida2- by a phosphonate group (IdaP3-) resulted in a significant increase in the stability of the metal complexes; however, this increase vanished with Ida2P4-, which was most likely due to some steric hindrance upon the coordination of the second large phosphonate group to form (5 + 5) joined chelates. In the phosphonate-containing systems, the neutral 1:1 complexes are the major species at pH 7.4 in the millimolar concentration range that is supported by both NMR and ESI-TOF-MS.
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Mészáros JP, Kandioller W, Spengler G, Prado-Roller A, Keppler BK, Enyedy ÉA. Half-Sandwich Rhodium Complexes with Releasable N-Donor Monodentate Ligands: Solution Chemical Properties and the Possibility for Acidosis Activation. Pharmaceutics 2023; 15:pharmaceutics15020356. [PMID: 36839678 PMCID: PMC9964319 DOI: 10.3390/pharmaceutics15020356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/14/2023] [Accepted: 01/17/2023] [Indexed: 01/24/2023] Open
Abstract
Cancer chemotherapeutics usually have serious side effects. Targeting the special properties of cancer and activation of the anticancer drug in the tumor microenvironment in situ may decrease the intensity of the side effects and improve the efficacy of therapy. In this study, half-sandwich Rh complexes are introduced, which may be activated at the acidic, extracellular pH of the tumor tissue. The synthesis and aqueous stability of mixed-ligand complexes with a general formula of [Rh(η5-Cp*)(N,N/O)(N)]2+/+ are reported, where (N,N/O) indicates bidentate 8-quinolate, ethylenediamine and 1,10-phenanthroline and (N) represents the releasable monodentate ligand with a nitrogen donor atom. UV-visible spectrophotometry, 1H NMR, and pH-potentiometry were used to determine the protonation constants of the monodentate ligands, the proton dissociation constants of the coordinated water molecules in the aqua complexes, and the formation constants of the mixed-ligand complexes. The obtained data were compared to those of the analogous Ru(η6-p-cymene) complexes. The developed mixed-ligand complexes were tested in drug-sensitive and resistant colon cancer cell lines (Colo205 and Colo320, respectively) and in four bacterial strains (Gram-positive and Gram-negative, drug-sensitive, and resistant) at different pH values (5-8). The mixed-ligand complexes with 1-methylimidazole displayed sufficient stability at pH 7.4, and their activation was found in cancer cells with decreasing pH; moreover, the mixed-ligand complexes demonstrated antimicrobial activity in Gram-positive and Gram-negative bacteria, including the resistant MRSA strain. This study proved the viability of incorporating releasable monodentate ligands into mixed-ligand half-sandwich complexes, which is supported by the biological assays.
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Affiliation(s)
- János P. Mészáros
- MTA-SZTE Lendület Functional Metal Complexes Research Group, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary
- Department of Inorganic and Analytical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary
- Correspondence: (J.P.M.); (É.A.E.)
| | - Wolfgang Kandioller
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 42, A-1090 Vienna, Austria
- Research Cluster “Translational Cancer Therapy Research”, University of Vienna, Währinger Str. 42, A-1090 Vienna, Austria
| | - Gabriella Spengler
- MTA-SZTE Lendület Functional Metal Complexes Research Group, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary
- Department of Medical Microbiology, Albert Szent-Györgyi Health Center and Albert Szent-Györgyi Medical School, University of Szeged, Semmelweis utca 6, H-6725 Szeged, Hungary
| | - Alexander Prado-Roller
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 42, A-1090 Vienna, Austria
- Research Cluster “Translational Cancer Therapy Research”, University of Vienna, Währinger Str. 42, A-1090 Vienna, Austria
| | - Bernhard K. Keppler
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 42, A-1090 Vienna, Austria
- Research Cluster “Translational Cancer Therapy Research”, University of Vienna, Währinger Str. 42, A-1090 Vienna, Austria
| | - Éva A. Enyedy
- MTA-SZTE Lendület Functional Metal Complexes Research Group, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary
- Department of Inorganic and Analytical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary
- Correspondence: (J.P.M.); (É.A.E.)
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Bíró L, Buglyó P, Farkas E. Diversity in the Interaction of Amino Acid- and Peptide-Based Hydroxamic Acids with Some Platinum Group Metals in Solution. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27030669. [PMID: 35163937 PMCID: PMC8839353 DOI: 10.3390/molecules27030669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 01/12/2022] [Accepted: 01/17/2022] [Indexed: 11/29/2022]
Abstract
Complexes that incorporate both ligand(s) and metal(s) exhibiting cytotoxic activity can especially be interesting to develop multifunctional drug molecules with desired activities. In this review, the limited number of solution results collected in our laboratory on the complexes of Pd(II) and two other platinum group metals—the half-sandwich type, [(η6-p-cym)Ru(H2O)3]2+, and [(η5-Cp*)Rh(H2O)3]2+—with hydroxamic acid derivatives of three amino acids, two imidazole analogues, and four small peptides are summarized and evaluated. Unlike the limited number of coordination sites of these metal ions (four and three for Pd(II) and the organometallic cations, respectively), the ligands discussed here offer a relatively high number of donor atoms as well as variation in their position within the ligands, resulting in a large versatility of the likely coordination modes. The review, besides presenting the solution equilibrium results, also discusses the main factors, such as (N,N) versus (O,O) chelate; size of chelate; amino-N versus imidazole-N; primary versus secondary hydroxamic function; differences between hydrolytic ability of the metal ions studied; and hydrolysis of the coordinated peptide hydroxamic acids in their Pd(II) complexes, which all determine the coordination modes present in the complexes formed in measurable concentrations in these systems. The options for the quantitative evaluation of metal binding effectivity and selectivity of the various ligands and the comparison with each other by using solution equilibrium data are also discussed.
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Pivarcsik T, Dömötör O, Mészáros JP, May NV, Spengler G, Csuvik O, Szatmári I, Enyedy ÉA. 8-Hydroxyquinoline-Amino Acid Hybrids and Their Half-Sandwich Rh and Ru Complexes: Synthesis, Anticancer Activities, Solution Chemistry and Interaction with Biomolecules. Int J Mol Sci 2021; 22:ijms222011281. [PMID: 34681939 PMCID: PMC8570331 DOI: 10.3390/ijms222011281] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 10/10/2021] [Accepted: 10/14/2021] [Indexed: 12/26/2022] Open
Abstract
Solution chemical properties of two novel 8-hydroxyquinoline-D-proline and homo-proline hybrids were investigated along with their complex formation with [Rh(η5-C5Me5)(H2O)3]2+ and [Ru(η6-p-cymene)(H2O)3]2+ ions by pH-potentiometry, UV-visible spectrophotometry and 1H NMR spectroscopy. Due to the zwitterionic structure of the ligands, they possess excellent water solubility as well as their complexes. The complexes exhibit high solution stability in a wide pH range; no significant dissociation occurs at physiological pH. The hybrids and their Rh(η5-C5Me5) complexes displayed enhanced cytotoxicity in human colon adenocarcinoma cell lines and exhibited multidrug resistance selectivity. In addition, the Rh(η5-C5Me5) complexes showed increased selectivity to the chemosensitive cancer cells over the normal cells; meanwhile, the Ru(η6-p-cymene) complexes were inactive, most likely due to arene loss. Interaction of the complexes with human serum albumin (HSA) and calf-thymus DNA (ct-DNA) was investigated by capillary electrophoresis, fluorometry and circular dichroism. The complexes are able to bind strongly to HSA and ct-DNA, but DNA cleavage was not observed. Changing the five-membered proline ring to the six-membered homoproline resulted in increased lipophilicity and cytotoxicity of the Rh(η5-C5Me5) complexes while changing the configuration (L vs. D) rather has an impact on HSA or ct-DNA binding.
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Affiliation(s)
- Tamás Pivarcsik
- MTA-SZTE Lendület Functional Metal Complexes Research Group, University of Szeged, Dóm Tér 7, H-6720 Szeged, Hungary; (T.P.); (O.D.); (J.P.M.); (G.S.)
- Department of Inorganic and Analytical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dóm Tér 7, H-6720 Szeged, Hungary
| | - Orsolya Dömötör
- MTA-SZTE Lendület Functional Metal Complexes Research Group, University of Szeged, Dóm Tér 7, H-6720 Szeged, Hungary; (T.P.); (O.D.); (J.P.M.); (G.S.)
- Department of Inorganic and Analytical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dóm Tér 7, H-6720 Szeged, Hungary
| | - János P. Mészáros
- MTA-SZTE Lendület Functional Metal Complexes Research Group, University of Szeged, Dóm Tér 7, H-6720 Szeged, Hungary; (T.P.); (O.D.); (J.P.M.); (G.S.)
- Department of Inorganic and Analytical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dóm Tér 7, H-6720 Szeged, Hungary
| | - Nóra V. May
- Centre for Structural Science, Research Centre for Natural Sciences, Magyar Tudósok Körútja 2, H-1117 Budapest, Hungary;
| | - Gabriella Spengler
- MTA-SZTE Lendület Functional Metal Complexes Research Group, University of Szeged, Dóm Tér 7, H-6720 Szeged, Hungary; (T.P.); (O.D.); (J.P.M.); (G.S.)
- Department of Medical Microbiology, Albert Szent-Györgyi Health Center and Albert Szent-Györgyi Medical School, University of Szeged, Semmelweis U. 6, H-6725 Szeged, Hungary
| | - Oszkár Csuvik
- Institute of Pharmaceutical Chemistry and Stereochemistry Research Group of Hungarian Academy of Sciences, University of Szeged, Eötvös U. 6, H-6720 Szeged, Hungary; (O.C.); (I.S.)
| | - István Szatmári
- Institute of Pharmaceutical Chemistry and Stereochemistry Research Group of Hungarian Academy of Sciences, University of Szeged, Eötvös U. 6, H-6720 Szeged, Hungary; (O.C.); (I.S.)
| | - Éva A. Enyedy
- MTA-SZTE Lendület Functional Metal Complexes Research Group, University of Szeged, Dóm Tér 7, H-6720 Szeged, Hungary; (T.P.); (O.D.); (J.P.M.); (G.S.)
- Department of Inorganic and Analytical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dóm Tér 7, H-6720 Szeged, Hungary
- Correspondence:
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Rubio AR, González R, Busto N, Vaquero M, Iglesias AL, Jalón FA, Espino G, Rodríguez AM, García B, Manzano BR. Anticancer Activity of Half-Sandwich Ru, Rh and Ir Complexes with Chrysin Derived Ligands: Strong Effect of the Side Chain in the Ligand and Influence of the Metal. Pharmaceutics 2021; 13:1540. [PMID: 34683834 PMCID: PMC8537477 DOI: 10.3390/pharmaceutics13101540] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/09/2021] [Accepted: 09/17/2021] [Indexed: 11/16/2022] Open
Abstract
An important challenge in the field of anticancer chemotherapy is the search for new species to overcome the resistance of standard drugs. An interesting approach is to link bioactive ligands to metal fragments. In this work, we have synthesized a set of p-cymene-Ru or cyclopentadienyl-M (M = Rh, Ir) complexes with four chrysin-derived pro-ligands with different -OR substituents at position 7 of ring A. The introduction of a piperidine ring on chrysin led to the highly cytotoxic pro-ligand HL4 and its metal complexes L4-M (SW480 and A549 cell lines, cytotoxic order: L4-Ir > L4-Ru ≈ L4-Rh). HL4 and its complexes induce apoptosis and can overcome cis-platinum resistance. However, HL4 turns out to be more cytotoxic in healthy than in tumor cells in contrast to its metal complexes which displayed higher selectivity than cisplatin towards cancer cells. All L4-M complexes interact with double stranded DNA. Nonetheless, the influence of the metal is clear because only complex L4-Ir causes DNA cleavage, through the generation of highly reactive oxygen species (1O2). This result supports the hypothesis of a potential dual mechanism consisting of two different chemical pathways: DNA binding and ROS generation. This behavior provides this complex with a great effectivity in terms of cytotoxicity.
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Affiliation(s)
- Ana R. Rubio
- Departamento de Química, Facultad de Ciencias, Universidad de Burgos, Plaza Misael Bañuelos s/n, 09001 Burgos, Spain; (A.R.R.); (M.V.); (G.E.); (B.G.)
| | - Rocío González
- Facultad de Ciencias y Tecnologías Químicas-IRICA, Universidad de Castilla-La Mancha, Avda. C. J. Cela 10, 13071 Ciudad Real, Spain; (R.G.); (A.L.I.); (F.A.J.)
| | - Natalia Busto
- Departamento de Química, Facultad de Ciencias, Universidad de Burgos, Plaza Misael Bañuelos s/n, 09001 Burgos, Spain; (A.R.R.); (M.V.); (G.E.); (B.G.)
| | - Mónica Vaquero
- Departamento de Química, Facultad de Ciencias, Universidad de Burgos, Plaza Misael Bañuelos s/n, 09001 Burgos, Spain; (A.R.R.); (M.V.); (G.E.); (B.G.)
| | - Ana L. Iglesias
- Facultad de Ciencias y Tecnologías Químicas-IRICA, Universidad de Castilla-La Mancha, Avda. C. J. Cela 10, 13071 Ciudad Real, Spain; (R.G.); (A.L.I.); (F.A.J.)
- Facultad de Ciencias de la Ingeniería y Tecnología (FCITEC), Universidad Autónoma de Baja California, Blvd. Universitario # 1000, Unidad Valle de las Palmas, Baja California, Tijuana 21500, Mexico
| | - Félix A. Jalón
- Facultad de Ciencias y Tecnologías Químicas-IRICA, Universidad de Castilla-La Mancha, Avda. C. J. Cela 10, 13071 Ciudad Real, Spain; (R.G.); (A.L.I.); (F.A.J.)
| | - Gustavo Espino
- Departamento de Química, Facultad de Ciencias, Universidad de Burgos, Plaza Misael Bañuelos s/n, 09001 Burgos, Spain; (A.R.R.); (M.V.); (G.E.); (B.G.)
| | - Ana M. Rodríguez
- Departamento de Química Inorgánica, Orgánica y Bioquímica, Escuela Técnica Superior de Ingenieros Industriales, Universidad de Castilla-La Mancha, Avda. C. J. Cela 2, 13071 Ciudad Real, Spain;
| | - Begoña García
- Departamento de Química, Facultad de Ciencias, Universidad de Burgos, Plaza Misael Bañuelos s/n, 09001 Burgos, Spain; (A.R.R.); (M.V.); (G.E.); (B.G.)
| | - Blanca R. Manzano
- Facultad de Ciencias y Tecnologías Químicas-IRICA, Universidad de Castilla-La Mancha, Avda. C. J. Cela 10, 13071 Ciudad Real, Spain; (R.G.); (A.L.I.); (F.A.J.)
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Dömötör O, Pivarcsik T, Mészáros JP, Szatmári I, Fülöp F, Enyedy ÉA. Critical factors affecting the albumin binding of half-sandwich Ru(ii) and Rh(iii) complexes of 8-hydroxyquinolines and oligopyridines. Dalton Trans 2021; 50:11918-11930. [PMID: 34374386 DOI: 10.1039/d1dt01700d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
There is significant interest today in the interaction of half-sandwich anticancer organometallic complexes with proteins. It is considered as a crucial factor in the transport and mode of action of these compounds; thus it can affect their overall pharmacological and toxicological profiles. Albumin binding of high stability Ru(ii)(η6-p-cymene) and Rh(iii)(η5-C5Me5) complexes formed with 8-hydroxyquinoline, its 5-chloro-7-((proline-1-yl)methyl) substituted derivative, 2,2'-bipyridine and 1,10-phenanthroline is discussed herein. The interaction with human serum albumin in terms of kinetic aspects, binding strength and possible binding sites was studied in detail by means of various methods such as 1H NMR spectroscopy, UV-visible spectrophotometry, steady-state and time-resolved fluorometry, ultrafiltration and capillary zone electrophoresis. Ru(ii)(η6-p-cymene)(2,2'-bipyridine) and Ru(ii)(η6-p-cymene)(1,10-phenanthroline) complexes do not bind to the protein measurably, most probably due to kinetic reasons. However, other complexes bind significantly to albumin with fairly different kinetics to albumin. The binding affinity towards hydrophobic binding pockets shows correlation with lipophilicity along with the actual charge of the respective complexes. The studied complexes preserve their original structure upon interaction with albumin. Formation constants computed for the binding of these metal complexes to histidine-containing model oligopeptides demonstrated significant ternary complex formation, pointing out the importance of histidine coordination in the binding of these types of complexes.
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Affiliation(s)
- Orsolya Dömötör
- Department of Inorganic and Analytical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dóm tér 7, H-6720, Szeged, Hungary.
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Nagy S, Ozsváth A, Bényei AC, Farkas E, Buglyó P. Donor Atom Preference of Organoruthenium and Organorhodium Cations on the Interaction with Novel Ambidentate (N,N) and (O,O) Chelating Ligands in Aqueous Solution. Molecules 2021; 26:molecules26123586. [PMID: 34208223 PMCID: PMC8230953 DOI: 10.3390/molecules26123586] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 06/04/2021] [Accepted: 06/04/2021] [Indexed: 11/16/2022] Open
Abstract
Two novel, pyridinone-based chelating ligands containing separated (O,O) and (Namino,Nhet) chelating sets (Namino = secondary amine; Nhet = pyrrole N for H(L3) (1-(3-(((1H-pyrrole-2-yl)methyl)-amino)propyl)-3-hydroxy-2-methylpyridin-4(1H)-one) or pyridine N for H(L5) (3-hydroxy-2-methyl-1-(3-((pyridin-2-ylmethyl)amino)propyl)pyridin-4(1H)-one)) were synthesized via reduction of the appropriate imines. Their proton dissociation processes were explored, and the molecular structures of two synthons were assessed by X-ray crystallography. These ambidentate chelating ligands are intended to develop Co(III)/PGM (PGM = platinum group metal) heterobimetallic multitargeted complexes with anticancer potential. To explore their metal ion binding ability, the interaction with Pd(II), [(η6-p-cym)Ru]2+ and [(η5-Cp*)Rh]2+ (p-cym = 1-methyl-4-isopropylbenzene, Cp* = pentamethyl-cyclopentadienyl anion) cations was studied in aqueous solution with the combined use of pH-potentiometry, NMR and HR ESI-MS. In general, organorhodium was found to form more labile complexes over ruthenium, while complexation of the (N,N) chelating set was slower than the processes of the pyridinone unit with (O,O) coordination. Formation of the organoruthenium complexes starts at lower pH (higher thermodynamic stabilities of the corresponding complexes) than for [(η5-Cp*)Rh]2+ but, due to the higher affinity of [η6-p-cym)Ru]2+ towards hydrolysis, the complexed ligands are capable of competing with hydroxide ion in a lesser extent than for the rhodium systems. As a result, under biologically relevant conditions, the rhodium binding effectivity of the ligands becomes comparable or even slightly higher than their effectivity towards ruthenium. Our results indicate that H(L3) is a less efficient (N,N) chelator for these metal ions than H(L5). Similarly, due to the relative effectivity of the (O,O) and (N,N) chelates at a 1:1 metal-ion-to-ligand ratio, H(L5) coordinates in a (N,N) manner to both cations in the whole pH range studied while, for H(L3), the complexation starts with (O,O) coordination. At a 2:1 metal-ion-to-ligand ratio, H(L3) cannot hinder the intensive hydrolysis of the second metal ion, although a small amount of 2:1 complex with [(η5-Cp*)Rh]2+ can also be detected.
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Affiliation(s)
- Sándor Nagy
- Department of Inorganic and Analytical Chemistry, University of Debrecen, H-4032 Debrecen, Hungary; (S.N.); (A.O.); (E.F.)
| | - András Ozsváth
- Department of Inorganic and Analytical Chemistry, University of Debrecen, H-4032 Debrecen, Hungary; (S.N.); (A.O.); (E.F.)
| | - Attila Cs. Bényei
- Department of Physical Chemistry, University of Debrecen, H-4032 Debrecen, Hungary;
| | - Etelka Farkas
- Department of Inorganic and Analytical Chemistry, University of Debrecen, H-4032 Debrecen, Hungary; (S.N.); (A.O.); (E.F.)
| | - Péter Buglyó
- Department of Inorganic and Analytical Chemistry, University of Debrecen, H-4032 Debrecen, Hungary; (S.N.); (A.O.); (E.F.)
- Correspondence:
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Mészáros JP, Pape VFS, Szakács G, Németi G, Dénes M, Holczbauer T, May NV, Enyedy ÉA. Half-sandwich organometallic Ru and Rh complexes of (N,N) donor compounds: effect of ligand methylation on solution speciation and anticancer activity. Dalton Trans 2021; 50:8218-8231. [PMID: 34032247 DOI: 10.1039/d1dt00808k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A series of half-sandwich polypyridyl complexes was synthesized and compared focusing on structural, cytotoxic and aqueous solution behaviour. The formula of the synthesized complexes is [M(arene)(N,N)Cl]Cl, where M: Ru or Rh, arene: p-cymene, toluene or C5Me5-, (N,N): 2,2'-bipyridine (bpy), 4,4'-dimethyl-2,2'-bipyridine (dmb), 1,10-phenanthroline (phen) or 2,9-dimethyl-1,10-phenanthroline (neo). The structures of five half-sandwich complexes were determined by X-ray crystallography. It was found that introducing methyl groups next to the coordinating nitrogen atoms of the bidentate ligand causes steric congestion around the metal centre which changes the angle between ligand planes. The ligands and the Rh complexes showed significant cytotoxicity in A2780 and MES-SA cancer cell lines (IC50 = 0.1-56 μM) and in the cisplatin-resistant A2780cis cells. Paradoxically, phen and dmb as well as their half-sandwich Rh complexes showed increased toxicity against multidrug resistant MES-SA/Dx5 cells. In contrast, coordination to Ru caused loss of toxicity. Solution equilibrium constants showed that the studied metal complexes have high stability, and no dissociation was found for Ru and Rh complexes even at micromolar concentrations in a wide pH range. However, in the case of Ru complexes a slow and irreversible decomposition, namely arene loss, was also observed, which was more pronounced in light exposure in aqueous solution. In the case of neo, the methyl groups next to the nitrogen atoms significantly decrease the stability of complexes. For Rh complexes, the order of the stability constants corrected with ligand basicity (log K*): 9.78 (phen) > 9.01 (dmb) > 8.89 (bpy) > 3.93 (neo). The coordinated neo resulted in an enormous decrease in the chloride ion affinity of Ru compounds. Based on the results, a universal model was introduced for the prediction of chloride ion capability of half-sandwich Rh and Ru complexes. It combines the effects of the bidentate ligand and the M(arene) part using only two terms, performing multilinear regression procedure.
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Affiliation(s)
- János P Mészáros
- Department of Inorganic and Analytical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary. and MTA-SZTE Lendület Functional Metal Complexes Research Group, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary
| | - Veronika F S Pape
- Institute of Enzymology, Research Centre for Natural Sciences, Magyar Tudósok körútja 2, H-1117 Budapest, Hungary and Department of Physiology, Semmelweis University, Tűzoltó utca 37-47, H-1094 Budapest, Hungary
| | - Gergely Szakács
- Institute of Enzymology, Research Centre for Natural Sciences, Magyar Tudósok körútja 2, H-1117 Budapest, Hungary and Institute of Cancer Research, Medical University of Vienna, Borschkegasse 8a, A-1090 Vienna, Austria
| | - Gábor Németi
- Department of Inorganic and Analytical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary.
| | - Márk Dénes
- Centre for Structural Science, Research Centre for Natural Sciences, Magyar tudósok körútja 2, H-1117 Budapest, Hungary
| | - Tamás Holczbauer
- Centre for Structural Science, Research Centre for Natural Sciences, Magyar tudósok körútja 2, H-1117 Budapest, Hungary and Institute of Organic Chemistry, Research Centre for Natural Sciences, Magyar tudósok körútja 2, H-1117 Budapest, Hungary
| | - Nóra V May
- Centre for Structural Science, Research Centre for Natural Sciences, Magyar tudósok körútja 2, H-1117 Budapest, Hungary
| | - Éva A Enyedy
- Department of Inorganic and Analytical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary. and MTA-SZTE Lendület Functional Metal Complexes Research Group, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary
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11
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Harringer S, Matzinger M, Gajic N, Hejl M, Jakupec MA, Kandioller W, Keppler BK. First insights into the novel class of organometallic compounds bearing a bidentate selenopyridone coordination motif: Synthesis, characterization, stability and biological investigations. Inorganica Chim Acta 2020. [DOI: 10.1016/j.ica.2020.119919] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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12
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Łomzik M, Hanif M, Budniok A, Błauż A, Makal A, Tchoń DM, Leśniewska B, Tong KKH, Movassaghi S, Söhnel T, Jamieson SMF, Zafar A, Reynisson J, Rychlik B, Hartinger CG, Plażuk D. Metal-Dependent Cytotoxic and Kinesin Spindle Protein Inhibitory Activity of Ru, Os, Rh, and Ir Half-Sandwich Complexes of Ispinesib-Derived Ligands. Inorg Chem 2020; 59:14879-14890. [PMID: 33003697 PMCID: PMC7584371 DOI: 10.1021/acs.inorgchem.0c00957] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Ispinesib is a potent inhibitor of kinesin spindle protein (KSP), which has been identified as a promising target for antimitotic anticancer drugs. Herein, we report the synthesis of half-sandwich complexes of Ru, Os, Rh, and Ir bearing the ispinesib-derived N,N-bidentate ligands (R)- and (S)-2-(1-amino-2-methylpropyl)-3-benzyl-7-chloroquinazolin-4(3H)-one and studies on their chemical and biological properties. Using the enantiomerically pure (R)- and (S)-forms of the ligand, depending on the organometallic moiety, either the SM,R or RM,S diastereomers, respectively, were observed in the molecular structures of the Ru- and Os(cym) (cym = η6-p-cymene) compounds, whereas the RM,R or SM,S diastereomers were found for the Rh- and Ir(Cp*) (Cp* = η5-pentamethylcyclopentadienyl) derivatives. However, density functional theory (DFT) calculations suggest that the energy difference between the diastereomers is very small, and therefore a mixture of both will be present in solution. The organometallics exhibited varying antiproliferative activity in a series of human cancer cell lines, with the complexes featuring the (R)-enantiomer of the ligand being more potent than the (S)-configured counterparts. Notably, the Rh and Ir complexes demonstrated high KSP inhibitory activity, even at 1 nM concentration, which was independent of the chirality of the ligand, whereas the Ru and especially the Os derivatives were much less active.
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Affiliation(s)
- Michał Łomzik
- Department of Organic Chemistry, Faculty of Chemistry, University of Łódź, ul. Tamka 12, 91-403 Łódź, Poland
| | - Muhammad Hanif
- School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Aleksandra Budniok
- Cytometry Lab, Department of Molecular Biophysics, Faculty of Biology and Environmental Protection, University of Łódź, ul. Pomorska 141/143, 90-236 Łódź, Poland
| | - Andrzej Błauż
- Cytometry Lab, Department of Molecular Biophysics, Faculty of Biology and Environmental Protection, University of Łódź, ul. Pomorska 141/143, 90-236 Łódź, Poland
| | - Anna Makal
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, ul. Żwirki i Wigury 101, 02-089 Warszawa, Poland
| | - Daniel M Tchoń
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, ul. Żwirki i Wigury 101, 02-089 Warszawa, Poland
| | - Barbara Leśniewska
- Faculty of Chemistry, University of Białystok, ul. K. Ciołkowskiego 1 K, 15-245 Białystok, Poland
| | - Kelvin K H Tong
- School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Sanam Movassaghi
- School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Tilo Söhnel
- School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Stephen M F Jamieson
- Auckland Cancer Society Research Centre, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Ayesha Zafar
- School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Jóhannes Reynisson
- School of Pharmacy and Bioengineering, Keele University, Hornbeam Building, Staffordshire ST5 5BG, United Kingdom
| | - Błażej Rychlik
- Cytometry Lab, Department of Molecular Biophysics, Faculty of Biology and Environmental Protection, University of Łódź, ul. Pomorska 141/143, 90-236 Łódź, Poland
| | - Christian G Hartinger
- School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Damian Plażuk
- Department of Organic Chemistry, Faculty of Chemistry, University of Łódź, ul. Tamka 12, 91-403 Łódź, Poland
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13
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Mészáros JP, Poljarević JM, Szatmári I, Csuvik O, Fülöp F, Szoboszlai N, Spengler G, Enyedy ÉA. An 8-hydroxyquinoline-proline hybrid with multidrug resistance reversal activity and the solution chemistry of its half-sandwich organometallic Ru and Rh complexes. Dalton Trans 2020; 49:7977-7992. [PMID: 32500882 DOI: 10.1039/d0dt01256d] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Herein the design and synthesis of a new 8-hydroxyquinoline derivative, (S)-5-chloro-7-((proline-1-yl)methyl)8-hydroxyquinoline (HQCl-Pro), with good water solubility and multidrug resistance reversal activity are reported. In this work the proton dissociation processes of HQCl-Pro and its complex formation with [Rh(η5-C5Me5)(H2O)3]2+, [Ru(η6-p-cymene)(H2O)3]2+ and [Ru(η6-toluene)(H2O)3]2+ were investigated by the combined use of pH-potentiometry, UV-visible spectrometry and 1H NMR spectroscopy. Our results revealed the prominent solution stability of the complexes in all cases. The lipophilicity of the complexes increased with the chloride ion concentration, and the complexes showed moderate log D values (-0.8 to +0.4) at pH 7.4 at all tested Cl- concentrations. The formation of mixed hydroxido complexes from the aqua complexes was characterized by relatively high pKa values (8.45-9.62 in chloride-free medium). Complexation processes are much slower with the Ru(η6-arene) triaqua cations than with [Rh(η5-C5Me5)(H2O)3]2+. Both the pKa values and H2O/Cl- exchange constants of the Ru-complexes are lower by 0.5-1.0 orders of magnitude than those of the Rh analogue. Arene loss (p-cymene and toluene) and oxidation were found in the case of Ru-complexes when an excess of HQCl-Pro and aromatic (N,N) bidentate ligands was added. The cytotoxicity and antiproliferative effect of HQCl-Pro and its complexes were assayed in vitro. In contrast to the structurally familiar 8-hydroxyquinoline, HQCl-Pro and its Rh(η5-C5Me5) complex were somewhat more effective against drug resistant Colo 320 adenocarcinoma human cells compared to the drug sensitive Colo 205 cells. The Ru- and Rh-complexes showed a similar metal uptake level after 4 h, while a longer incubation time resulted in higher cellular Rh concentration.
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Affiliation(s)
- János P Mészáros
- Department of Inorganic and Analytical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary.
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Shiekh BA. Hierarchy of Commonly Used DFT Methods for Predicting the Thermochemistry of Rh-Mediated Chemical Transformations. ACS OMEGA 2019; 4:15435-15443. [PMID: 31572844 PMCID: PMC6761679 DOI: 10.1021/acsomega.9b01563] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 09/04/2019] [Indexed: 06/10/2023]
Abstract
The accuracy and reliability of 17 commonly used density functionals in conjunction with Poisson-Boltzmann finite solvation model were gauged for predicting the free energy of Rh(I)- and Rh(III)-mediated chemical transformations such as ligand exchange, hydride elimination, dihydrogen elimination, chloride affinity, and silyl hydride bond activation reactions. In total, six Rh-mediated reactions were examined, and the computed density functional theory results were then subjected to comparison with the experimentally reported values. For reaction A, involving replacement of N2 with η2-H2 over Rh(I), MPWB1K-D3, B3PW91, B3LYP, and BHandHYLP emerged to be the best functionals of all the tested methods in terms of their deviations ≤2 kcal mol-1 from experimental data. For reaction B, in which exchange of η2-C2H4 with N2 over Rh(I) takes place, MPWB1K-D3 and M06-2X-D3 functionals performed the best, while as for reaction C (hydride elimination reaction in Rh(III) complex), it is PBE functional that showed impressive performance. Similarly, for reaction D (H2 elimination reaction in Rh(III) complex), PBE0-D3 and PBE-D3 showed exceptional results compared to other functionals. For reaction E (H2O/Cl- exchange), the PBE0 again shows impressive performance as compared to other functionals. For reaction F (Si-H activation), M06-2X-D3, PBE0-D3, and MPWB1K-D3 functionals are undoubtedly the best functionals. Overall, PBE0-D3 and MPWB1K-D3 functionals were impressive in all cases with lowest mean unsigned errors (3.2 and 3.4 kcal mol-1, respectively) with respect to experimental Gibbs free energies. Thus, these two functionals are recommended for studying Rh-mediated chemical transformations.
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Dömötör O, Enyedy ÉA. Binding mechanisms of half-sandwich Rh(III) and Ru(II) arene complexes on human serum albumin: a comparative study. J Biol Inorg Chem 2019; 24:703-719. [PMID: 31300922 PMCID: PMC6682546 DOI: 10.1007/s00775-019-01683-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 06/27/2019] [Indexed: 02/05/2023]
Abstract
Abstract Various half-sandwich ruthenium(II) arene complexes and rhodium(III) arene complexes have been intensively investigated due to their prominent anticancer activity. The interaction of the organometallic complexes of Ru(η6-p-cymene) and Rh(η5-C5Me5) with human serum albumin (HSA) was studied in detail by a combination of various methods such as ultrafiltration, capillary electrophoresis, 1H NMR spectroscopy, fluorometry and UV–visible spectrophotometry in the presence of 100 mM chloride ions. Binding characteristics of the organometallic ions and their complexes with deferiprone, 2-picolinic acid, maltol, 6-methyl-2-picolinic acid and 2-quinaldic acid were evaluated. Kinetic aspects and reversibility of the albumin binding are also discussed. The effect of low-molecular-mass blood components on the protein binding was studied in addition to the interaction of organorhodium complexes with cell culture medium components. The organometallic ions were found to bind to HSA to a high extent via a coordination bond. Release of the bound metal ions was kinetically hindered and could not be induced by the denaturation of the protein. Binding of the Ru(η6-p-cymene) triaqua cation was much slower (ca. 24 h) compared to the rhodium congener (few min), while their complexes interacted with the protein relatively fast (1–2 h). The studied complexes were bound to HSA coordinatively. The highly stable and kinetically inert 2-picolinate Ru(η6-p-cymene) complex bound in an associative manner preserving its original entity, while lower stability complexes decomposed partly or completely upon binding to HSA. Fast, non-specific and high-affinity binding of the complexes on HSA highlights their coordinative interaction with various types of proteins possibly decreasing effective drug concentration. Graphic abstract ![]()
Electronic supplementary material The online version of this article (10.1007/s00775-019-01683-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Orsolya Dömötör
- Department of Inorganic and Analytical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dóm tér 7, 6720, Szeged, Hungary.
| | - Éva A Enyedy
- Department of Inorganic and Analytical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dóm tér 7, 6720, Szeged, Hungary.
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Mészáros JP, Poljarevic JM, Gál GT, May NV, Spengler G, Enyedy ÉA. Comparative solution and structural studies of half-sandwich rhodium and ruthenium complexes bearing curcumin and acetylacetone. J Inorg Biochem 2019; 195:91-100. [PMID: 30928657 DOI: 10.1016/j.jinorgbio.2019.02.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 02/15/2019] [Accepted: 02/26/2019] [Indexed: 01/29/2023]
Abstract
Half-sandwich organometallic complexes of curcumin are extensively investigated as anticancer compounds. Speciation studies were performed to explore the solution stability of curcumin complexes formed with [Rh(η5-C5Me5)(H2O)3]2+. Acetylacetone (Hacac), as the simplest β-diketone ligand bearing (O,O) donor set, was involved for comparison and its Ru(η6‑p‑cymene), Ru(η6‑toluene) complexes were also studied. 1H NMR, UV-visible and pH-potentiometric titrations revealed a clear trend of stability constants of the acac complexes: Ru(η6‑p‑cymene) > Ru(η6‑toluene) > Rh(η5-C5Me5). Despite this order, the highest extent of complex formation is seen for the Rh(η5-C5Me5) complexes at pH 7.4. Formation constant of [Rh(η5-C5Me5)(H2curcumin)(H2O)]+ reveals similar solution stability to that of the acac complex. Additionally, structures of two complexes were determined by X-ray crystallography. The in vitro cytotoxicity of curcumin was not improved by the complexation with these organometallic cations.
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Affiliation(s)
- János P Mészáros
- Department of Inorganic and Analytical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary
| | - Jelena M Poljarevic
- Department of Inorganic and Analytical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary; University of Belgrade - Faculty of Chemistry, Studentski trg 12-16, 11000 Belgrade, Serbia
| | - G Tamás Gál
- Research Centre for Natural Sciences Hungarian Academy of Sciences, Magyar tudósok körútja 2, H-1117 Budapest, Hungary
| | - Nóra V May
- Research Centre for Natural Sciences Hungarian Academy of Sciences, Magyar tudósok körútja 2, H-1117 Budapest, Hungary
| | - Gabriella Spengler
- Department of Medical Microbiology and Immunobiology, University of Szeged, Dóm tér 10, H-6720 Szeged, Hungary
| | - Éva A Enyedy
- Department of Inorganic and Analytical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary.
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