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Rodrigues CV, Johnson KR, Lombardi VC, Rodrigues MO, Sobrinho JA, de Bettencourt-Dias A. Photocytotoxicity of Thiophene- and Bithiophene-Dipicolinato Luminescent Lanthanide Complexes. J Med Chem 2021; 64:7724-7734. [PMID: 34018753 DOI: 10.1021/acs.jmedchem.0c01805] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
New thiophene-dipicolinato-based compounds, K2nTdpa (n = 1, 2), were isolated. Their anions are sensitizers of lanthanide ion (LnIII) luminescence and singlet oxygen generation (1O2). Emission in the visible and near-infrared regions was observed for the LnIII complexes with efficiencies (ϕLn) ϕEu = 33% and ϕYb = 0.31% for 1Tdpa2- and ϕYb = 0.07% for 2Tdpa2-. The latter does not sensitize EuIII emission. Fluorescence imaging of HeLa live cells incubated with K3[Eu(1Tdpa)3] indicates that the complex permeates the cell membrane and localizes in the mitochondria. All complexes generate 1O2 in solution with efficiencies (ϕO12) as high as 13 and 23% for the GdIII complexes of 1Tdpa2- and 2Tdpa2-, respectively. [Ln(nTdpa)3]3- (n = 1, 2) are phototoxic to HeLa cells when irradiated with UV light with IC50 values as low as 4.2 μM for [Gd(2Tdpa)3]3- and 91.8 μM for [Eu(1Tdpa)3]3-. Flow cytometric analyses indicate both apoptotic and necrotic cell death pathways.
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Affiliation(s)
- Carime V Rodrigues
- Department of Chemistry, University of Nevada, Reno, Reno, Nevada 89557, United States.,Laboratório de Inorgânica e Materiais, Instituto de Química, Universidade de Brasília, Campus Universitário Darcy Ribeiro, Brasilia 70910-900 DF, Brazil
| | - Katherine R Johnson
- Department of Chemistry, University of Nevada, Reno, Reno, Nevada 89557, United States
| | - Vincent C Lombardi
- Department of Microbiology and Immunology, University of Nevada, Reno, Reno, Nevada 89557, United States
| | - Marcelo O Rodrigues
- Laboratório de Inorgânica e Materiais, Instituto de Química, Universidade de Brasília, Campus Universitário Darcy Ribeiro, Brasilia 70910-900 DF, Brazil
| | - Josiane A Sobrinho
- Department of Chemistry, University of Nevada, Reno, Reno, Nevada 89557, United States
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Hernández-Morales A, Rivera JM, López-Monteon A, Lagunes-Castro S, Castillo-Blum S, Cureño-Hernández K, Flores-Parra A, Villaseñor-Granados O, Colorado-Peralta R. Complexes containing benzimidazolyl-phenol ligands and Ln(III) ions: Synthesis, spectroscopic studies and preliminary cytotoxicity evaluation. J Inorg Biochem 2019; 201:110842. [PMID: 31536950 DOI: 10.1016/j.jinorgbio.2019.110842] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 09/06/2019] [Accepted: 09/07/2019] [Indexed: 11/18/2022]
Abstract
Fourteen new complexes were obtained from Ln(III)(NO3)3∙n-H2O and the chromophores 2-(1H-benzo[d]imidazol-2-yl)-phenol (Bzp1) or 2-(5-methyl-1H-benzo[d]imidazol-2-yl)-phenol (Bzp2). The complete characterization allowed us to assign unequivocally the structures of all the complexes. The techniques used for this purpose were Ultraviolet-Visible (UV-Vis) and Fourier-Transform Infrared (FT-IR) spectroscopies, High-Resolution Mass Spectrometry (HRMS), Magnetic Susceptibility (MS), Elemental Analysis (EA) and Molar Conductivity (MC). HRMS allowed us to find the molecular ion and its isotopic pattern. The FT-IR spectral data suggested that benzimidazolyl-phenol ligands coordinate with Ln(III) ions through iminic nitrogen and phenolic oxygen. Thermogravimetric Analysis (TGA) studies of NdBzp1 and GdBzp2 complexes indicate the presence of lattice water along with three nitrates and two benzimidazolyl-phenol ligands; the thermal decomposition was consistent with the minimal formula suggested by EA. The coordination type of the benzimidazolyl-phenol ligands, the geometry and the structural organization of these coordination complexes have been interpreted by Density Functional Theory (DFT) calculations, and they coincided with the physicochemical data suggesting a coordination number eight for the Ln(III) ions. The cytotoxicity of the chromophores and their coordination complexes was tested against a cancer cell line (HeLa), as compared with structure/support cells (NIH-3T3) and defense cells (J774A.1), revealing that three coordination complexes showed moderate cytotoxicity against the cell lines studied.
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Affiliation(s)
| | - José María Rivera
- Maestría en Ciencias en Procesos Biológicos, FCQ-UV, C.P. 94340 Orizaba, Ver., Mexico
| | - Aracely López-Monteon
- Maestría en Ciencias en Procesos Biológicos, FCQ-UV, C.P. 94340 Orizaba, Ver., Mexico
| | | | | | | | | | | | - Raúl Colorado-Peralta
- Maestría en Ciencias en Procesos Biológicos, FCQ-UV, C.P. 94340 Orizaba, Ver., Mexico.
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Piccinelli F, De Rosa C, Melchior A, Faura G, Tolazzi M, Bettinelli M. Eu(iii) and Tb(iii) complexes of 6-fold coordinating ligands showing high affinity for the hydrogen carbonate ion: a spectroscopic and thermodynamic study. Dalton Trans 2019; 48:1202-1216. [PMID: 30460363 DOI: 10.1039/c8dt03621g] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
In the present contribution, four classes of Ln(iii) complexes (Ln = Eu and Tb) have been synthesized and characterized in aqueous solution. They differ by charge, Ln(bpcd)+ [bpcd2- = N,N'-bis(2-pyridylmethyl)-trans-1,2-diaminocyclohexane N,N'-diacetate] and Ln(bQcd)+ (bQcd2- = N,N'-bis(2-quinolinmethyl)-trans-1,2-diaminocyclohexane N,N'-diacetate) being positively charged and Ln(PyC3A) (PyC3A3- = N-picolyl-N,N',N'-trans-l,2-cyclohexylenediaminetriacetate) and Ln(QC3A) (QC3A3- = N-quinolyl-N,N',N'-trans-l,2-cyclohexylenediaminetriacetate) being neutral. Combined DFT, spectrophotometric and potentiometric studies reveal the presence, under physiological conditions (pH 7.4), of a couple of equally and highly stable isomers differing by the stereochemistry of the ligands (trans-N,N and trans-O,O for bpcd2- and bQcd2-; trans-O,O and trans-N,O for PyC3A3- and QC3A3-). Their high log β values (9.97 < log β < 15.68), the presence of an efficient antenna effect and the strong increase of the Ln(iii) luminescence intensity as a function of the hydrogen carbonate concentration in physiological solution, render these complexes as very promising optical probes for a selective detection of HCO3-in cellulo or in extracellular fluid. This particularly applies to the cationic Eu(bpcd)+, Tb(bpcd)+ and Eu(bQcd)+ complexes, which are capable of guesting up to two hydrogen carbonate anions in the inner coordination sphere of the metal ion, so that they show an unprecedented affinity towards HCO3- (log K for the formation of the adduct in the 4.6-5.9 range).
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Affiliation(s)
- Fabio Piccinelli
- Laboratorio Materiali Luminescenti, DB, Università di Verona, and INSTM, UdR Verona, Strada Le Grazie 15, 37134 Verona, Italy.
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Abstract
Lanthanide bioprobes and bioconjugates are ideal luminescent stains in view of their low propensity to photobleaching, sharp emission lines and long excited state lifetimes permitting time-resolved detection for enhanced sensitivity. We show here how the interplay between physical, chemical and biochemical properties allied to microfluidics engineering leads to self-assembled dinuclear lanthanide luminescent probes illuminating live cells and selectively detecting biomarkers expressed by cancerous human breast cells.
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Affiliation(s)
- Jean-Claude G Bünzli
- Institute of Chemical Sciences and Engineering , École Polytechnique Fédérale de Lausanne , BCH 1402, 1015 Lausanne , Switzerland
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Peterson KL, Dang JV, Weitz EA, Lewandowski C, Pierre VC. Effect of lanthanide complex structure on cell viability and association. Inorg Chem 2014; 53:6013-21. [PMID: 24901440 PMCID: PMC4060611 DOI: 10.1021/ic500282n] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A systematic study of the effect of hydrophobicity and charge on the cell viability and cell association of lanthanide metal complexes is presented. The terbium luminescent probes feature a macrocyclic polyaminocarboxylate ligand (DOTA) in which the hydrophobicity of the antenna and that of the carboxyamide pendant arms are independently varied. Three sensitizing antennas were investigated in terms of their function in vitro: 2-methoxyisophthalamide (IAM(OMe)), 2-hydroxyisophthalamide (IAM), and 6-methylphenanthridine (Phen). Of these complexes, Tb-DOTA-IAM exhibited the highest quantum yield, although the higher cell viability and more facile synthesis of the structurally related Tb-DOTA-IAM(OMe) platform renders it more attractive. Further modification of this latter core structure with carboxyamide arms featuring hydrophobic benzyl, hexyl, and trifluoro groups as well as hydrophilic amino acid based moieties generated a family of complexes that exhibit high cell viability (ED50 > 300 μM) regardless of the lipophilicity or the overall complex charge. Only the hexyl-substituted complex reduced cell viability to 60% in the presence of 100 μM complex. Additionally, cellular association was investigated by ICP-MS and fluorescence microscopy. Surprisingly, the hydrophobic moieties did not increase cell association in comparison to the hydrophilic amino acid derivatives. It is thus postulated that the hydrophilic nature of the 2-methoxyisophthalamide antenna (IAM(OMe)) disfavors the cellular association of these complexes. As such, responsive luminescent probes based on this scaffold would be appropriate for the detection of extracellular species.
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Affiliation(s)
- Katie L Peterson
- Department of Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
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Rajendran M, Yapici E, Miller LW. Lanthanide-based imaging of protein-protein interactions in live cells. Inorg Chem 2014; 53:1839-53. [PMID: 24144069 PMCID: PMC3944735 DOI: 10.1021/ic4018739] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In order to deduce the molecular mechanisms of biological function, it is necessary to monitor changes in the subcellular location, activation, and interaction of proteins within living cells in real time. Förster resonance energy-transfer (FRET)-based biosensors that incorporate genetically encoded, fluorescent proteins permit high spatial resolution imaging of protein-protein interactions or protein conformational dynamics. However, a nonspecific fluorescence background often obscures small FRET signal changes, and intensity-based biosensor measurements require careful interpretation and several control experiments. These problems can be overcome by using lanthanide [Tb(III) or Eu(III)] complexes as donors and green fluorescent protein (GFP) or other conventional fluorophores as acceptors. Essential features of this approach are the long-lifetime (approximately milliseconds) luminescence of Tb(III) complexes and time-gated luminescence microscopy. This allows pulsed excitation, followed by a brief delay, which eliminates nonspecific fluorescence before the detection of Tb(III)-to-GFP emission. The challenges of intracellular delivery, selective protein labeling, and time-gated imaging of lanthanide luminescence are presented, and recent efforts to investigate the cellular uptake of lanthanide probes are reviewed. Data are presented showing that conjugation to arginine-rich, cell-penetrating peptides (CPPs) can be used as a general strategy for the cellular delivery of membrane-impermeable lanthanide complexes. A heterodimer of a luminescent Tb(III) complex, Lumi4, linked to trimethoprim and conjugated to nonaarginine via a reducible disulfide linker rapidly (∼10 min) translocates into the cytoplasm of Maden Darby canine kidney cells from the culture medium. With this reagent, the intracellular interaction between GFP fused to FK506 binding protein 12 (GFP-FKBP12) and the rapamycin binding domain of mTOR fused to Escherichia coli dihydrofolate reductase (FRB-eDHFR) were imaged at high signal-to-noise ratio with fast (1-3 s) image acquisition using a time-gated luminescence microscope. The data reviewed and presented here show that lanthanide biosensors enable fast, sensitive, and technically simple imaging of protein-protein interactions in live cells.
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Affiliation(s)
- Megha Rajendran
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, IL 60607
| | - Engin Yapici
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, IL 60607
| | - Lawrence W. Miller
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, IL 60607
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Deiters E, Eliseeva SV, Bünzli JCG. Self-assembly of a helical zinc-europium complex: speciation in aqueous solution and luminescence. Front Chem 2013; 1:15. [PMID: 24790943 PMCID: PMC3982565 DOI: 10.3389/fchem.2013.00015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Accepted: 08/13/2013] [Indexed: 11/13/2022] Open
Abstract
Two new tridentate(NNO)-bidentate(NN) compartmental ligands, HL5 and HL6, are synthesized from pyridine and benzimidazole synthons. They react in aqueous solution under physiological conditions with ZnII, LnIII, or a mixture thereof, to yield complexes of different stoichiometries, 1:3, 2:2, 2:3, 1:1:3, the speciation of which is established by UV-visible titrations and ESI mass spectrometry. Photophysical studies of the EuIII-containing solutions in Tris-HCl 0.1 M (pH = 7.4) show that lanthanide luminescence arises from a unique N6O3 coordination site with pseudo D3 symmetry. Relevant parameters such as crystal field splitting, lifetime, radiative lifetime, and intrinsic quantum yield perfectly match those reported for dinuclear 4f-4f helicates in which the EuIII ion has the same coordination environment.
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Affiliation(s)
- Emmanuel Deiters
- Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland
| | - Svetlana V Eliseeva
- Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland ; Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR 4301 Orléans, France
| | - Jean-Claude G Bünzli
- Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland ; Department of Advanced Materials Chemistry, WCU Center for Next Generation Photovoltaic Systems, Korea University Sejong-si, South Korea
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