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1.
Dalton Trans ; 48(47): 17461-17471, 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31513202

RESUMO

A symmetric osmium(ii) [bis-(4'-(4-carboxyphenyl)-2,2':6',2''-terpyridine)] was prepared and conjugated to two mitochondrial-targeting peptide sequences; FrFKFrFK (r = d-arginine). The parent and conjugate complexes showed strong near infra-red emission centred at λmax 745 nm that was modestly oxygen dependent in the case of the parent and oxygen independent in the case of the conjugate, attributed in the latter case, surprisingly, to a shorter emission lifetime of the conjugate compared to the parent. Confocal fluorescence imaging of sub-live HeLa and MCF 7 cells showed the parent complex was cell impermeable whereas the conjugate was rapidly internalised into the cell and distributed in a concentration dependent manner. At concentrations below approximately 30 µmol, the conjugate localised to the mitochondria of both cell types where it was observed to trigger apoptosis induced by the collapse of the mitochondrial membrane potential (MPP). At concentrations exceeding 30 µmol the conjugate was similarly internalised rapidly but distributed throughout the cell, including to the nucleus and nucleolus. At these concentrations, it was observed to precipitate a caspase-dependent apoptotic pathway. The combination of concentration dependent organelle targeting, NIR emission coincident with the biological window, and distribution dependent cytotoxicity offers an interesting approach to theranostics with the possibility of eliciting site dependent therapeutic effect whilst monitoring the therapeutic effect with luminescence imaging.


Assuntos
Antineoplásicos/farmacologia , Complexos de Coordenação/farmacologia , Corantes Fluorescentes/farmacologia , Mitocôndrias/efeitos dos fármacos , Osmio/farmacologia , Piridinas/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Morte Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Complexos de Coordenação/síntese química , Complexos de Coordenação/química , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/química , Células HeLa , Humanos , Células MCF-7 , Mitocôndrias/metabolismo , Estrutura Molecular , Osmio/química , Piridinas/química , Relação Estrutura-Atividade , Células Tumorais Cultivadas
2.
Anal Chim Acta ; 1067: 56-62, 2019 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-31047149

RESUMO

Altered glycosylation is a universal feature of cancer cells and certain glycans are well-known markers of tumor progression. In this work we studied two glycan isomers, 2,3-sialyllactose (3-SL) and 2,6-sialyllactose (6-SL), frequently appearing in glycoproteins connected with cancer. A combination of square wave voltammetry and glycan modification with osmium(VI) N,N,N',N'-tetramethylethylenediamine (Os(VI)tem) allowed to distinguish between these regioisomers, since the 6-SL molecule can bind three Os(VI), while the 3-SL only two Os(VI) moieties, as experiments using capillary electrophoresis, inductively coupled plasma mass spectrometry and thin layer chromatography showed. A similar pattern of Os(VI)-modification was found for isomers of sialyl-N-acetyllactosamine and sialylgalactose. Covalent adducts of Os(VI)tem with glycans yielded three reduction voltammetric peaks. The ratio of peak I/peak II heights depends on the content of individual regioisomer in the sample. Our proposed approach allows the determination of isomer percentage representation in the mixture after one voltammogram recording. These results show a new appropriate method for the discrimination of glycan isomers containing terminal sialic acid important for distinguishing between cancerous and non-cancerous origin of biomarkers.


Assuntos
Complexos de Coordenação/química , Técnicas Eletroquímicas , Lactose/análogos & derivados , Osmio/química , Ácidos Siálicos/análise , Ácidos Siálicos/química , Humanos , Lactose/análise , Lactose/química , Estereoisomerismo
3.
J Immunol ; 202(10): 3103-3112, 2019 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-30988119

RESUMO

Polystyrene beads are broadly applied in flow cytometry. Implementing bead-based assays in mass cytometry is desired but hampered by the lack of an elemental label required for their detection. In this study, we introduce stable osmium tetroxide labeling as a universal approach for generating functionalized beads readily detectable by mass cytometry. We demonstrate the utility of osmium-labeled beads for signal spillover compensation in mass cytometry, and, strikingly, their application in quantitative Ab-binding capacity assays combined with high-dimensional profiling of human PBMC enabled the systematic assessment of receptor expression profiles across large numbers of cellular phenotypes. This analysis confirmed increased monocytic Siglec-1 expression in active systemic lupus erythematosus patients and, additionally, revealed interrelated reductions of CD4 expression by regulatory and memory CD4 T cells and HLA-DR expression by myeloid dendritic cells, pointing toward defective cross-talk at the immunological synapse that may limit immune responses in systemic lupus erythematosus. By converting conventional flow cytometry beads into beads suitable for mass cytometry, our approach paves the way toward the broad implementation of bead-based assays in high-dimensional cell profiling studies by mass cytometry in biomedical research.


Assuntos
Citometria de Fluxo , Regulação da Expressão Gênica/imunologia , Antígenos HLA-DR , Lúpus Eritematoso Sistêmico , Microesferas , Osmio/química , Linfócitos T Reguladores , Adulto , Idoso , Feminino , Antígenos HLA-DR/sangue , Antígenos HLA-DR/imunologia , Humanos , Memória Imunológica , Lúpus Eritematoso Sistêmico/sangue , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/patologia , Masculino , Pessoa de Meia-Idade , Poliestirenos/química , Coloração e Rotulagem , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Linfócitos T Reguladores/patologia
4.
Microscopy (Oxf) ; 68(3): 243-253, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-30860257

RESUMO

This study was designed to observe osteoclasts in the rat femora by light and electron microscopic cytochemistry for nicotinamide adenine dinucleotide phosphatase (NADPase) and arylsulfatase, and scanning electron microscopy using osmium maceration to assess the three-dimensional morphology of the Golgi apparatus in osteoclasts. The Golgi apparatus showed strong NADPase activity and surrounded each nucleus with the cis-side facing the nucleus. The Golgi apparatus could be often traced for a length of 20 µm or longer. Observations of serial semi-thin sections confirmed that a single line of reaction products (=lead precipitates) intervened somewhere between any two neighboring nuclei. The nuclear membrane showed strong arylsulfatase activity as well as rough endoplasmic reticulum and lysosomes. Scanning electron microscopy showed that the Golgi apparatus covered the nucleus in a porous sheet-like configuration. Under magnification, the cis-most saccule showed a sieve-like configuration with fine fenestrations. The saccules decreased fenestration numbers toward the trans-side and displayed a more plate-like appearance. The above findings indicate the following. (1) The Golgi saccules of osteoclasts have a three-dimensional structure comparable with that generally seen in other cell types. (2) The Golgi apparatus forms a porous multi-spherical structure around nuclei. Within the structure, in most cases a Golgi stack partitions the room into several compartments in each of which a nucleus fits. (3) The nuclear membrane synthesizes some kinds of proteins more stably and sufficiently than the rough endoplasmic reticulum. Consequently, the Golgi apparatus accumulates around nuclei with the cis-side facing the nucleus.


Assuntos
Arilsulfatases/metabolismo , Complexo de Golgi/ultraestrutura , NAD/química , Osteoclastos/ultraestrutura , Pirofosfatases/metabolismo , Animais , Retículo Endoplasmático Rugoso/metabolismo , Complexo de Golgi/metabolismo , Lisossomos/metabolismo , Masculino , Microscopia Eletrônica de Varredura , Membrana Nuclear/metabolismo , Osmio/química , Ratos , Ratos Wistar
5.
Methods Mol Biol ; 1880: 211-221, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30610699

RESUMO

Autophagy-related organelles, including omegasomes, isolation membranes (or phagophores), autophagosomes, and autolysosomes, are characterized by dynamic changes in lipid membranes including morphology as well as their associated proteins. Therefore, it is critical to define and track membranous elements for identification and detailed morphological analyses of these organelles. However, it is often difficult to clearly observe these organelles with good morphology in conventional electron microscopy (EM), thus hampering 3D analyses and correlative light-electron microscopy (CLEM). Here, we focus on describing fixation procedures using (1) ferrocyanide-reduced osmium for CLEM and (2) aldehyde/OsO4 mixture for detecting omegasome structures and isolation membrane-associated tubules (IMATs). These methods can be easily applied to cultured mammalian cells for conventional and cutting-edge EM analyses, leading to a better understanding of ultrastructural details in autophagosome formation.


Assuntos
Autofagossomos/ultraestrutura , Autofagia , Microscopia Eletrônica/métodos , Fixação de Tecidos/métodos , Aldeídos/química , Animais , Linhagem Celular , Ferrocianetos/química , Fibroblastos/ultraestrutura , Indicadores e Reagentes/química , Camundongos , Microscopia Confocal/métodos , Imagem Óptica/métodos , Osmio/química , Tetróxido de Ósmio/química , Oxirredução , Inclusão do Tecido/métodos
6.
Anal Bioanal Chem ; 411(9): 1887-1894, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30324259

RESUMO

Alpha-1-acid glycoprotein (AGP) is a serum glycoprotein whose levels are increased two or three times during disease or injury. This makes it a potential biomarker for inflammatory bowel diseases and sepsis. Consequently, fast, simple, and cheap analytical methods for prognosis, diagnosis, and follow-up of these diseases are demanded. In this work, we propose a simple electrochemical approach based on carbon nanotubes scaffold films (CNSFs) for total AGP determination in serum samples. Firstly, AGP is labeled with an electrochemical tag (osmium(VI) complex), and then the total amount of AGP is quantified by adsorptive transfer stripping square wave voltammetry (AdTSWV). Multi-walled carbon nanotubes scaffold films (MWSFs) yielded the best analytical performance in terms of sensitivity with a good limit of detection of 0.6 mg L-1 for AGP determination in serum samples, in less than 20 min. A simplified AGP calibration and its sequential serum sample analysis strategy with good accuracy (81%) and excellent reproducibility (RSD < 1%) was additionally proposed to meet the point-of-care/needs requirements. Graphical abstract Multi-walled carbon nanotubes scaffold films for total AGP determination on disposable platforms integrating single-point calibration and sequential sample analysis.


Assuntos
Técnicas Eletroquímicas/métodos , Nanotubos de Carbono/química , Orosomucoide/análise , Adsorção , Calibragem , Humanos , Limite de Detecção , Osmio/química , Espectroscopia Fotoeletrônica , Sistemas Automatizados de Assistência Junto ao Leito , Reprodutibilidade dos Testes , Soro
7.
Anal Sci ; 35(1): 103-106, 2019 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-30146546

RESUMO

A novel flexible lactate sensor based on organic field-effect transistors (OFETs) is demonstrated. Because lactate is known as a biomarker for assessing our physical performance, wearable lactate sensors could contribute to the monitoring of human health conditions. The flexible and low-voltage operatable OFET possesses an extended-gate modified with enzymes and an osmium-redox polymer for the lactate detection, meaning that the continuous measurement of lactate levels (0 - 10 mM) has been successfully achieved. We believe that insight obtained will open up opportunities for applying OFETs in wearable biosensors.


Assuntos
Técnicas Biossensoriais/instrumentação , Enzimas Imobilizadas/química , Ácido Láctico/análise , Polímeros/química , Transistores Eletrônicos , Eletrodos , Peroxidase do Rábano Silvestre/química , Oxigenases de Função Mista/química , Osmio/química , Oxirredução , Maleabilidade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Propriedades de Superfície
8.
Chem Commun (Camb) ; 55(11): 1548-1551, 2019 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-30534756

RESUMO

A dual signal amplification method based on surface-enhanced Raman scattering (SERS) is developed by photo-triggered release of SERS probes from mesoporous silica-coated Au nanorods (SiO2@Au) and the use of a specially-designed SERS substrate with an internal reference. Two metal carbonyl (metal-CO) labels (Os-SCO and Re-SCO) are proposed here as novel interference-free labels. Results demonstrate that tumor-related DNA can be quantitatively detected by this reliable and ultra-sensitive SERS platform.


Assuntos
Complexos de Coordenação/química , DNA de Neoplasias/análise , Nanotubos/química , Análise Espectral Raman , DNA de Neoplasias/metabolismo , Ouro/química , Humanos , Lasers , Neoplasias/genética , Neoplasias/patologia , Osmio/química , Rênio/química , Dióxido de Silício/química
9.
Inorg Chem ; 57(22): 14427-14434, 2018 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-30406647

RESUMO

The promise of the metal(arene) structure as an anticancer pharmacophore has prompted intensive exploration of this chemical space. While N-heterocyclic carbene (NHC) ligands are widely used in catalysis, they have only recently been considered in metal complexes for medicinal applications. Surprisingly, a comparatively small number of studies have been reported in which the NHC ligand was coordinated to the RuII(arene) pharmacophore and even less with an OsII(arene) pharmacophore. Here, we present a systematic study in which we compared symmetrically substituted methyl and benzyl derivatives with the nonsymmetric methyl/benzyl analogues. Through variation of the metal center and the halido ligands, an in-depth study was conducted on ligand exchange properties of these complexes and their biomolecule binding, noting in particular the stability of the M-CNHC bond. In addition, we demonstrated the ability of the complexes to inhibit the selenoenzyme thioredoxin reductase (TrxR), suggested as an important target for anticancer metal-NHC complexes, and their cytotoxicity in human tumor cells. It was found that the most potent TrxR inhibitor diiodido(1,3-dibenzylbenzimidazol-2-ylidene)(η6-p-cymene)ruthenium(II) 1bI was also the most cytotoxic compound of the series, with the antiproliferative effects in general in the low to middle micromolar range. However, since there was no clear correlation between TrxR inhibition and antiproliferative potency across the compounds, TrxR inhibition is unlikely to be the main mode of action for the compound type and other target interactions must be considered in future.


Assuntos
Antineoplásicos/farmacologia , Benzimidazóis/farmacologia , Complexos de Coordenação/farmacologia , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Antineoplásicos/toxicidade , Benzimidazóis/síntese química , Benzimidazóis/química , Benzimidazóis/toxicidade , Linhagem Celular Tumoral , Complexos de Coordenação/síntese química , Complexos de Coordenação/química , Complexos de Coordenação/toxicidade , Citocromos c/química , DNA/química , Estabilidade de Medicamentos , Feminino , Humanos , Camundongos Endogâmicos BALB C , Simulação de Dinâmica Molecular , Estrutura Molecular , Osmio/química , Rutênio/química , Relação Estrutura-Atividade , Tiorredoxina Dissulfeto Redutase/antagonistas & inibidores , Ubiquitina/química
10.
Dalton Trans ; 47(42): 14841-14854, 2018 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-30325378

RESUMO

Recent work has shown that the chemical reactivity of osmium complexes can be finely tuned by the choice of osmium oxidation state, the ligands (including C- and N-bound), and the coordination geometry and stereochemistry, so opening up a wide range of new potential biological and medical applications. Osmium cancer therapeutics can have diverse modes of action and targets, including DNA interactions, redox modulation and protein inhibition. Polypyridyl Os(ii) compounds have potential advantages for luminescent cell imaging and photodynamic therapy due to their favourable photophysical and photochemical properties, such as long-wavelength metal-ligand charge transfer (MLCT) absorptions, high photostability and useful near-infrared (NIR) emission. Here we summarize recent progress in the design and application of innovative organo-osmium compounds as anticancer agents with novel mechanisms and as organelle-targeted imaging probes.


Assuntos
Antineoplásicos/farmacologia , Complexos de Coordenação/farmacologia , Corantes Fluorescentes/farmacologia , Neoplasias/tratamento farmacológico , Osmio/farmacologia , Fármacos Fotossensibilizantes/farmacologia , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Complexos de Coordenação/síntese química , Complexos de Coordenação/química , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/química , Humanos , Ligantes , Conformação Molecular , Neoplasias/diagnóstico por imagem , Neoplasias/metabolismo , Organelas/efeitos dos fármacos , Organelas/metabolismo , Osmio/química , Fotoquimioterapia , Fármacos Fotossensibilizantes/síntese química , Fármacos Fotossensibilizantes/química
11.
Inorg Chem ; 57(21): 13201-13212, 2018 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-30351084

RESUMO

The series of complexes [Os(bpy)3- n(pytz) n][PF6]2 (bpy = 2,2'-bipyridyl, pytz = 1-benzyl-4-(pyrid-2-yl)-1,2,3-triazole, 1 n = 0, 2 n = 1, 3 n = 2, 4 n = 3) were prepared and characterized and are rare examples of luminescent 1,2,3-triazole-based osmium(II) complexes. For 3 we present an attractive and particularly mild preparative route via an osmium(II) η6-arene precursor circumventing the harsh conditions that are usually required. Because of the high spin-orbit coupling constant associated with the Os(II) center the absorption spectra of the complexes all display absorption bands of appreciable intensity in the range of 500-700 nm corresponding to spin-forbidden ground-state-to-3MLCT transitions (MLCT = metal-to-ligand charge transfer), which occur at significantly lower energies than the corresponding spin-allowed 1MLCT transitions. The homoleptic complex 4 is a bright emitter (λmaxem = 614 nm) with a relatively high quantum yield of emission of ∼40% in deoxygenated acetonitrile solutions at room temperature. Water-soluble chloride salts of 1-4 were also prepared, all of which remain emissive in aerated aqueous solutions at room temperature. The complexes were investigated for their potential as phosphorescent cellular imaging agents, whereby efficient excitation into the 3MLCT absorption bands at the red side of the visible range circumvents autofluorescence from biological specimens, which do not absorb in this region of the spectrum. Confocal microscopy reveals 4 to be readily taken up by cancer cell lines (HeLa and EJ) with apparent lysosomal and endosomal localization, while toxicity assays reveal that the compounds have low dark and light toxicity. These complexes therefore provide an excellent platform for the development of efficient luminescent cellular imaging agents with advantageous photophysical properties that enable excitation and emission in the biologically transparent region of the optical spectrum.


Assuntos
Complexos de Coordenação/química , Substâncias Luminescentes/química , Imagem Óptica , Osmio/química , Piridinas/química , Triazóis/química , Sobrevivência Celular/efeitos dos fármacos , Complexos de Coordenação/síntese química , Complexos de Coordenação/farmacologia , Células HeLa , Humanos , Substâncias Luminescentes/síntese química , Substâncias Luminescentes/farmacologia , Medições Luminescentes , Estrutura Molecular , Processos Fotoquímicos , Teoria Quântica , Células Tumorais Cultivadas
12.
Chem Commun (Camb) ; 54(79): 11120-11123, 2018 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-30204166

RESUMO

A series of six osmium(ii) complexes of the type [(η6-p-cymene)Os(C^N)X] (X = chlorido or acetato) containing benzimidazole C^N ligands with an ester group as a handle for further functionalization have been synthesized. They exhibit IC50 values in the low micromolar range in a panel of cisplatin (CDDP)-resistant cancer cells (approximately 10× more cytotoxic than CDDP in MCF-7), decrease the levels of intracellular ROS and reduce the NAD+ coenzyme, and inhibit tubulin polymerization. This discovery could open the door to a new large family of osmium(ii)-based bioconjugates with diverse modes of action.


Assuntos
Antineoplásicos/farmacologia , Antioxidantes/farmacologia , Benzimidazóis/farmacologia , Complexos de Coordenação/farmacologia , Osmio/química , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Antioxidantes/síntese química , Antioxidantes/química , Apoptose/efeitos dos fármacos , Benzimidazóis/síntese química , Benzimidazóis/química , Linhagem Celular Tumoral , Chlorocebus aethiops , Cisplatino/farmacologia , Colchicina/farmacologia , Complexos de Coordenação/síntese química , Complexos de Coordenação/química , Ensaios de Seleção de Medicamentos Antitumorais , Pontos de Checagem da Fase G1 do Ciclo Celular/efeitos dos fármacos , Humanos , Ligantes , NAD/metabolismo , Necrose/induzido quimicamente , Espécies Reativas de Oxigênio/metabolismo , Moduladores de Tubulina/síntese química , Moduladores de Tubulina/química , Moduladores de Tubulina/farmacologia
13.
J Med Chem ; 61(20): 9246-9255, 2018 10 25.
Artigo em Inglês | MEDLINE | ID: mdl-30230827

RESUMO

Platinum drugs are widely used for cancer treatment. Other precious metals are promising, but their clinical progress depends on achieving different mechanisms of action to overcome Pt-resistance. Here, we evaluate 13 organo-Os complexes: 16-electron sulfonyl-diamine catalysts [(η6-arene)Os( N, N')], and 18-electron phenylazopyridine complexes [(η6-arene)Os( N, N')Cl/I]+ (arene = p-cymene, biphenyl, or terphenyl). Their antiproliferative activity does not depend on p21 or p53 status, unlike cisplatin, and their selective potency toward cancer cells involves the generation of reactive oxygen species. Evidence of such a mechanism of action has been found both in vitro and in vivo. This work appears to provide the first study of osmium complexes in the zebrafish model, which has been shown to closely model toxicity in humans. A fluorescent osmium complex, derived from a lead compound, was employed to confirm internalization of the complex, visualize in vivo distribution, and confirm colocalization with reactive oxygen species generated in zebrafish.


Assuntos
Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Compostos Organometálicos/química , Compostos Organometálicos/farmacologia , Osmio/química , Platina/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Humanos
14.
Dalton Trans ; 47(35): 12197-12208, 2018 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-30112527

RESUMO

There is an urgent need to discover new, selective compounds to add to the limited arsenal of chemotherapeutics displaying selective toxicity for aggressive triple-negative breast cancer (TNBC) cells. The effect of two, recently developed metal-based half-sandwich complexes [Os(η6-pcym)(bphen)(dca)]PF6 (Os-dca) and [Ru(η6-pcym)(bphen)(dca)]PF6 (Ru-dca) [pcym = 1-methyl-4-(propan-2-yl)benzene (p-cymene); bphen = 4,7-diphenyl-1,10-phenanthroline (bathophenanthroline); dca = dichloroacetate] on triple-negative breast cancer cells MDA-MB-231 is reported. The complexes display selective toxicity in several tumor cells (at submicromolar concentrations), and a prominent effect is observed against highly progressive triple negative breast cancer MDA-MB-231 cells for Os-dca. The lower potency of Ru-dca in comparison with Os-dca is apparently connected with a relatively quick release of the dca ligand due to the hydrolysis of Ru-dca before this complex enters the cells. Remarkably, both Os-dca and Ru-dca reduce successfully metastasis-related properties of the triple-negative breast cancer cells such as migration, invasion, and re-adhesion. The anti-metastatic effects of Os-dca and Ru-dca are associated with their ability to suppress matrix metalloproteinase activity and/or production and reduce the expression of aquaporins. Further detailed mechanistic studies reveal that Os-dca reverses Warburg's effect and oncosis seems to be a prominent mode of cell death that predominates over apoptosis. As such, Os-dca can efficiently overcome the resistance of cancer cells to clinically-used apoptotic inducers cisplatin and carboplatin. The cytostatic and anti-metastatic properties of Os-dca in MDA-MB-231 provide a strong impetus for the development of new metal-based compounds to target hardly treatable human TNBC cells and displaying different modes of action compared to the antitumor metallodrugs in clinical use.


Assuntos
Antineoplásicos/farmacologia , Complexos de Coordenação/farmacologia , Osmio/farmacologia , Fenantrolinas/farmacologia , Rutênio/farmacologia , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/patologia , Antineoplásicos/síntese química , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Complexos de Coordenação/síntese química , Complexos de Coordenação/química , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Estrutura Molecular , Osmio/química , Fenantrolinas/química , Rutênio/química
15.
Chembiochem ; 19(15): 1653-1656, 2018 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-29799158

RESUMO

5-Methylcytidine (m5 C) and 5-methyluridine (m5 U) are highly abundant post-transcriptionally modified nucleotides that are observed in various natural RNAs. Such nucleotides were labeled through a chemical approach, as both underwent oxidation at the C5=C6 double bond, leading to the formation of osmium-bipyridine complexes, which could be identified by mass spectrometry. This osmium tag made it possible to distinguished m5 C and m5 U from their isomers, 2'-O-methylcytidine and 2'-O-methyluridine, respectively. Queuosine and 2-methylthio-N6 -isopentenyladenosine in tRNA were also tagged through complex formation.


Assuntos
Citidina/análogos & derivados , Osmio/química , Processamento Pós-Transcricional do RNA , RNA/química , Uridina/análogos & derivados , Citidina/análise , Isomerismo , Espectrometria de Massas , Oxirredução , Uridina/análise
16.
Anal Chem ; 90(12): 7139-7147, 2018 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-29808995

RESUMO

By taking advantage of the spectral properties of metal carbonyls, we have designed a surface-enhanced Raman spectroscopy (SERS) ratiometric assay for measuring cell-free circulating DNA (cfDNA) from Epstein-Barr virus in blood for nasopharyngeal carcinoma (NPC). This assay consists of a rhenium carbonyl (Re-CO) to serve as a DNA probe, an osmium carbonyl (Os-CO) embedded within the SERS-active substrate as an internal reference, and a streptavidin layer on the surface of the substrate. Hybridization of cfDNA with biotinylated-capture sequence leads to immobilization of cfDNA on the substrate. The binding of Re-CO via daunorubicin (DNR) to cfDNA is accompanied by an appearance of a strong symmetry stretching vibrations peak at 2113 cm-1, which has spectral overlap with Os-CO (2025 cm-1). This results in an increase in the I2113/ I2025 ratio and quantitatively correlates with cfDNA. This SERS assay can be readily used to detect cfDNA in blood samples from patients due to the intensity ratio of I2113/ I2025 lying in a silent region (1780-2200 cm-1) in the SERS spectrum of the biomolecules.


Assuntos
Monóxido de Carbono/química , Ácidos Nucleicos Livres/sangue , DNA Viral/sangue , Herpesvirus Humano 4/genética , Osmio/química , Rênio/química , Ácidos Nucleicos Livres/genética , DNA Viral/genética , Herpesvirus Humano 4/isolamento & purificação , Humanos , Reação em Cadeia da Polimerase em Tempo Real , Análise Espectral Raman , Propriedades de Superfície
17.
J Inorg Biochem ; 185: 26-29, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29730234

RESUMO

Microfocus synchrotron x-ray fluorescence (SXRF) imaging focussed on detection of the Os LIII edge shows that the organo­osmium metallodrug candidate [(ŋ6-p-cym)Os(Azpy-NMe2)I]+ (p-cym = p-cymene, Azpy-NMe2 = 2-(p-([dimethylamino]phenylazo)pyridine)) [1] penetrates efficiently into the interior of A2780 human ovarian cancer cell spheroids, a model for a solid tumour. The accompanying changes in Zn and Ca distribution suggest that the complex causes nuclear damage and initiates signalling events for cell death, consistent with findings for cultured cancer cell monolayers. Such tumour penetration is likely to be important for combatting resistance to chemotherapy, which is becoming a problem for current clinical platinum drugs.


Assuntos
Antineoplásicos/farmacocinética , Compostos Organometálicos/farmacocinética , Osmio/farmacocinética , Espectrometria por Raios X/métodos , Antineoplásicos/química , Cálcio/metabolismo , Linhagem Celular Tumoral , Feminino , Humanos , Compostos Organometálicos/química , Osmio/química , Neoplasias Ovarianas/metabolismo , Neoplasias Ovarianas/patologia , Esferoides Celulares/metabolismo , Síncrotrons , Zinco/metabolismo
18.
Dalton Trans ; 47(16): 5714-5724, 2018 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-29632937

RESUMO

The [Os(η6-pcym)(dpa)(VP)]PF6 (1-VP) complex contains the histone deacetylase (HDAC) inhibitor valproate (2-propylpentanoate; VP) as a monodentate O-donor ligand and shows ca. 3-fold higher in vitro cytotoxicity against A2780 human ovarian carcinoma cells than its chlorido analogue [Os(η6-pcym)(dpa)Cl]PF6 (1-Cl); pcym = 1-methyl-4-(propan-2-yl)benzene (p-cymene), dpa = 2,2'-dipyridylamine. The complex 1-VP showed promising selectivity towards the A2780 ovarian carcinoma cell line (IC50 = 20.9 µM) over normal human hepatocytes (IC50 > 200.0 µM). Moreover, the complex 1-VP was found to be inactive against MCF-7 (breast adenocarcinoma), PANC-1 (pancreatic adenocarcinoma) and HT-29 (colon carcinoma) up to a concentration of 100 µM. Detailed flow cytometry studies indicated that treatment of A2780 cells with complex 1-VP led to induction of apoptosis, production of reactive oxygen species (ROS) and superoxide (SO) anion radicals, as well as mitochondrial membrane potential depletion and cell cycle perturbations. The microscopic assessment (standard hematoxylin/eosin staining) revealed signs of morphological changes associated with the progression of apoptosis in A2780 cells treated with the IC50 concentration of the complex 1-VP. Consistent with the intracellular production of ROS and SO, the complex 1-VP induced hydroxyl radical formation, as proved by EPR spin trapping experiments. This case study suggests that replacement of the chlorido ligand of half-sandwich Os(ii) complexes by a releasable monodentate biologically active ligand (e.g., VP used in this study) is an effective strategy for the development of novel non-platinum cytotoxic agents.


Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Complexos de Coordenação/química , Complexos de Coordenação/farmacologia , Osmio/química , 2,2'-Dipiridil/análogos & derivados , 2,2'-Dipiridil/química , Antineoplásicos/síntese química , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Complexos de Coordenação/síntese química , Cimenos , Humanos , Concentração Inibidora 50 , Membranas Mitocondriais/efeitos dos fármacos , Monoterpenos/química , Espécies Reativas de Oxigênio/metabolismo , Superóxidos/metabolismo , Ácido Valproico/análogos & derivados , Ácido Valproico/química
19.
Molecules ; 23(2)2018 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-29443934

RESUMO

We report on the preparation and thorough characterization of cytotoxic half-sandwich complexes [Ru(η6-pcym)(bphen)(dca)]PF6 (Ru-dca) and [Os(η6-pcym)(bphen)(dca)]PF6 (Os-dca) containing dichloroacetate(1-) (dca) as the releasable O-donor ligand bearing its own cytotoxicity; pcym = 1-methyl-4-(propan-2-yl)benzene (p-cymene), bphen = 4,7-diphenyl-1,10-phenanthroline (bathophenanthroline). Complexes Ru-dca and Os-dca hydrolyzed in the water-containing media, which led to the dca ligand release (supported by ¹H NMR and electrospray ionization mass spectra). Mass spectrometry studies revealed that complexes Ru-dca and Os-dca do not interact covalently with the model proteins cytochrome c and lysozyme. Both complexes exhibited slightly higher in vitro cytotoxicity (IC50 = 3.5 µM for Ru-dca, and 2.6 µM for Os-dca) against the A2780 human ovarian carcinoma cells than cisplatin (IC50 = 5.9 µM), while their toxicity on the healthy human hepatocytes was found to be IC50 = 19.1 µM for Ru-dca and IC50 = 19.7 µM for Os-dca. Despite comparable cytotoxicity of complexes Ru-dca and Os-dca, both the complexes modified the cell cycle, mitochondrial membrane potential, and mitochondrial cytochrome c release by a different way, as revealed by flow cytometry experiments. The obtained results point out the different mechanisms of action between the complexes.


Assuntos
Complexos de Coordenação/química , Ácido Dicloroacético/química , Neoplasias Ovarianas/tratamento farmacológico , Fenantrolinas/química , Proliferação de Células/efeitos dos fármacos , Complexos de Coordenação/farmacologia , Ácido Dicloroacético/farmacologia , Liberação Controlada de Fármacos , Feminino , Humanos , Ligantes , Osmio/química , Fenantrolinas/farmacologia , Rutênio/química
20.
Nat Chem ; 10(3): 347-354, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29461524

RESUMO

Catalytic anticancer metallodrugs active at low doses could minimize side-effects, introduce novel mechanisms of action that combat resistance and widen the spectrum of anticancer-drug activity. Here we use highly stable chiral half-sandwich organometallic Os(II) arene sulfonyl diamine complexes, [Os(arene)(TsDPEN)] (TsDPEN, N-(p-toluenesulfonyl)-1,2-diphenylethylenediamine), to achieve a highly enantioselective reduction of pyruvate, a key intermediate in metabolic pathways. Reduction is shown both in aqueous model systems and in human cancer cells, with non-toxic concentrations of sodium formate used as a hydride source. The catalytic mechanism generates selectivity towards ovarian cancer cells versus non-cancerous fibroblasts (both ovarian and lung), which are commonly used as models of healthy proliferating cells. The formate precursor N-formylmethionine was explored as an alternative to formate in PC3 prostate cancer cells, which are known to overexpress a deformylase enzyme. Transfer-hydrogenation catalysts that generate reductive stress in cancer cells offer a new approach to cancer therapy.


Assuntos
Antineoplásicos/farmacologia , Compostos Organometálicos/farmacologia , Osmio/farmacologia , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/metabolismo , Antineoplásicos/síntese química , Antineoplásicos/química , Catálise/efeitos dos fármacos , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Fibroblastos/efeitos dos fármacos , Humanos , Hidrogenação/efeitos dos fármacos , Modelos Moleculares , Estrutura Molecular , Compostos Organometálicos/síntese química , Compostos Organometálicos/química , Osmio/química , Neoplasias Ovarianas/patologia , Relação Estrutura-Atividade
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