RESUMEN
Hydroxyl radical (·OH) scavenging capacity (HOSC) estimation is essential for evaluating antioxidants, natural extracts, or drugs against clinical diseases. While nanozymes offer advantages in related applications, they still face limitations in activity and selectivity. In response, this work showcases the fabrication of laminarin-modulated osmium (laminarin-Os) nanoclusters (1.45 ± 0.05 nm), functioning as peroxidase-like nanozymes within a colorimetric assay tailored for rational HOSC estimation. This study validates both the characterization and remarkable stability of laminarin-Os. By leveraging the abundant surface negative charges of laminarin-Os and the surface hydroxyls of laminarin, oxidation reactions are facilitated, augmenting laminarin-Os's affinity for 3,3',5,5'-tetramethylbenzidine (TMB) (KM = 0.04 mM). This enables the laminarin-Os-based colorimetric assay to respond to ·OH more effectively than citrate-, albumin-, or other polysaccharides-based Os. In addition, experimental results also validate the selective peroxidase-like behavior of laminarin-Os under acidic conditions. Antioxidants like ascorbic acid, glutathione, tannic acid, and cysteine inhibit absorbance at 652 nm in the colorimetric platform using laminarin-Os's peroxidase-like activity. Compared with commercial kits, this assay demonstrates superior sensitivity (e.g., responds to ascorbic acid 0.01-0.075 mM, glutathione 1-15 µg/mL, tannic acid 0.5-5 µM, and monoammonium glycyrrhizinate cysteine 1.06-10.63 µM) and HOSC testing for glutathione, tannic acid, and monoammonium glycyrrhizinate cysteine. Overall, this study introduces a novel Os nanozyme with exceptional TMB affinity and ·OH selectivity, paving the way for HOSC estimation in biomedical research, pharmaceutical analysis, drug quality control, and beyond.
Asunto(s)
Bencidinas , Depuradores de Radicales Libres , Glucanos , Radical Hidroxilo , Osmio , Bencidinas/química , Colorimetría/métodos , Depuradores de Radicales Libres/química , Depuradores de Radicales Libres/farmacología , Glucanos/química , Radical Hidroxilo/química , Radical Hidroxilo/análisis , Osmio/química , Oxidación-Reducción , Peroxidasa/química , Peroxidasa/metabolismoRESUMEN
Anticancer agents that exhibit catalytic mechanisms of action offer a unique multi-targeting strategy to overcome drug resistance. Nonetheless, many in-cell catalysts in development are hindered by deactivation by endogenous nucleophiles. We have synthesised a highly potent, stable Os-based 16-electron half-sandwich ('piano stool') catalyst by introducing a permanent covalent tether between the arene and chelated diamine ligand. This catalyst exhibits antiproliferative activity comparable to the clinical drug cisplatin towards triple-negative breast cancer cells and can overcome tamoxifen resistance. Speciation experiments revealed Os to be almost exclusively albumin-bound in the extracellular medium, while cellular accumulation studies identified an energy-dependent, protein-mediated Os accumulation pathway, consistent with albumin-mediated uptake. Importantly, the tethered Os complex was active for in-cell transfer hydrogenation catalysis, initiated by co-administration of a non-toxic dose of sodium formate as a source of hydride, indicating that the Os catalyst is delivered to the cytosol of cancer cells intact. The mechanism of action involves the generation of reactive oxygen species (ROS), thus exploiting the inherent redox vulnerability of cancer cells, accompanied by selectivity for cancerous cells over non-tumorigenic cells.
Asunto(s)
Antineoplásicos , Proliferación Celular , Complejos de Coordinación , Osmio , Humanos , Catálisis , Antineoplásicos/farmacología , Antineoplásicos/química , Antineoplásicos/síntesis química , Osmio/química , Osmio/farmacología , Proliferación Celular/efectos de los fármacos , Complejos de Coordinación/química , Complejos de Coordinación/farmacología , Complejos de Coordinación/síntesis química , Femenino , Línea Celular Tumoral , Especies Reactivas de Oxígeno/metabolismo , Neoplasias de la Mama/patología , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/metabolismo , Ensayos de Selección de Medicamentos Antitumorales , Estructura MolecularRESUMEN
Diabetic wounds are susceptible to bacterial infections, largely linked to high blood glucose levels (hyperglycemia). To treat such wounds, enzymes like glucose oxidase (GOx) can be combined with nanozymes (nanomaterials mimic enzymes) to use glucose effectively for purposes. However, there is still room for improvement in these systems, particularly in terms of process simplification, enzyme activity regulation, and treatment effects. Herein, the approach utilizes GOx to directly facilitate the biomineralized growth of osmium (Os) nanozyme (GOx-OsNCs), leading to dual-active centers and remarkable triple enzyme activities. Initially, GOx-OsNCs use vicinal dual-active centers, enabling a self-cascaded mechanism that significantly enhances glucose sensing performance compared to step-by-step reactions, surpassing the capabilities of other metal sources such as gold and platinum. In addition, GOx-OsNCs are integrated into a glucose-sensing gel, enabling instantaneous visual feedback. In the treatment of infected diabetic wounds, GOx-OsNCs exhibit multifaceted benefits by lowering blood glucose levels and exhibiting antibacterial properties through the generation of hydroxyl free radicals, thereby expediting healing by fostering a favorable microenvironment. Furthermore, the catalase-like activity of GOx-OsNCs aids in reducing oxidative stress, inflammation, and hypoxia, culminating in improved healing outcomes. Overall, this synergistic enzyme-nanozyme blend is user-friendly and holds considerable promise for diverse applications.
Asunto(s)
Glucosa Oxidasa , Osmio , Glucosa Oxidasa/química , Glucosa Oxidasa/metabolismo , Animales , Osmio/química , Antibacterianos/farmacología , Antibacterianos/química , Antibacterianos/uso terapéutico , Cicatrización de Heridas/efectos de los fármacos , Ratones , Glucemia/metabolismo , Diabetes Mellitus Experimental , Humanos , Glucosa/metabolismo , Infección de Heridas/tratamiento farmacológico , Infección de Heridas/metabolismoRESUMEN
Five osmium(II) polypyridyl complexes of the general formula [Os(4,7-diphenyl-1,10-phenanthroline)2 L]2+ were synthesized as photosensitizers for photodynamic therapy by varying the nature of the ligand L. Thanks to the pronounced π-extended structure of the ligands and the heavy atom effect provided by the osmium center, these complexes exhibit a high absorption in the near-infrared (NIR) region (up to 740â nm), unlike related ruthenium complexes. This led to a promising phototoxicity in vitro against cancer cells cultured as 2D cell layers but also in multicellular tumor spheroids upon irradiation at 740â nm. The complex [Os(4,7-diphenyl-1,10-phenanthroline)2 (2,2'-bipyridine)]2+ was found to be the most efficient against various cancer cell lines, with high phototoxicity indexes. Experiments on CT26 tumor-bearing BALB/c mice also indicate that the OsII complexes could significantly reduce tumor growth following 740â nm laser irradiation. The high phototoxicity in the biological window of this structurally simple complex makes it a promising photosensitizer for cancer treatment.
Asunto(s)
Complejos de Coordinación , Neoplasias , Fotoquimioterapia , Rutenio , Animales , Ratones , Fármacos Fotosensibilizantes/farmacología , Fármacos Fotosensibilizantes/uso terapéutico , Fármacos Fotosensibilizantes/química , Osmio/química , Complejos de Coordinación/farmacología , Complejos de Coordinación/uso terapéutico , Complejos de Coordinación/química , Neoplasias/tratamiento farmacológico , Rutenio/farmacología , Rutenio/químicaRESUMEN
Influence of the metal center on hydrolysis of organometallic anticancer complexes containing an N-phenyl-2-pyridinecarbothioamide (PCA) ligand, [M(η6-p-cymene)(N-phenyl-2-pyridinecarbothioamide)Cl]+ (M = RuII, 1A, and OsII, 2A), as well as their N-fluorophenyl derivatives [M(η6-p-cymene)(N-fluorophenyl-2-pyridinecarbothioamide)Cl]+ (M = RuII, 1B, and OsII, 2B) have been investigated using the DFT method in aqueous medium. The activation energy barriers for the hydrolysis of 1A (21.5 kcal/mol) and 1B (20.7 kcal/mol) are found to be significantly lower than those of their corresponding osmium analogs 2A (28.6 kcal/mol) and 2B (27.5 kcal/mol). DFT evaluated results reveal the inertness of Os(II)-PCA complex toward the hydrolysis that rationalizes the experimental observations. However, the incorporation of fluoride substituent slightly decreases the activation energy for the hydrolysis of Ru(II)- and Os(II)-PCA. In addition, the interaction of hydrolyzed Ru(II)-PCAs (1AH and 1BH) and Os(II)-PCAs (2AH and 2BH) complexes with the histidine (Hist) have also been investigated. The aquated 1BH and 2BH show an enhanced propensity toward the interaction with histidine, and their activation Gibbs free energies are calculated to be 15.9 and 18.9 kcal/mol, respectively. ONIOM (QM/MM) study of the resulting aquated complexes inside histone protein shows the maximum stability of the 2BH complex having a binding energy of -43.6 kcal/mol.
Asunto(s)
Antineoplásicos , Compuestos Organometálicos , Rutenio , Osmio/química , Rutenio/química , Histidina , Hidrólisis , Antineoplásicos/farmacología , Antineoplásicos/química , Compuestos Organometálicos/químicaRESUMEN
We have recently reported a series of half-sandwich ruthenium(II) complexes with curcuminoid ligands showing excellent cytotoxic activities (particularly ionic derivatives containing PTA (PTA = 1,3,5-triaza-7-phosphaadamantane). In the present study, new members of this family of compounds have been prepared with the objective to investigate the effect of a long hydrophobic chain obtained by replacing the OH-groups, present in curcumin and bisdemethoxycurcumin, with the palmitic acid ester. We report the synthesis of ruthenium(II) and osmium(II) p-cymene derivatives containing palmitic acid curcumin ester ligands ((1E,3Z,6E)-3-hydroxy-5-oxohepta-1,3,6-triene-1,7-diyl)bis(2-methoxy-4,1-phenylene)dipalmitate (p-curcH) and ((1E,3Z,6E)-3-hydroxy-5-oxohepta-1,3,6-triene-1,7-diyl)bis(4,1-phenylene)dipalmitate (p-bdcurcH). Complexes [M(II)(cym)(p-curc)/(p-bdcurc)(Cl)] 1-4 (M = Ru or Os) are neutral, whereas [M(II)(cym)(p-curc)/(p-bdcurc)(PTA)][SO3CF3] 5-8 are salts obtained when the chloride ligand is replaced by the PTA ligand. Stability studies performed on 1-8 in DMSO-PBS under physiological conditions (pH = 7.4) indicate that the complexes remain intact. The complexes exhibit potent and selective cytotoxic activity against an ovarian carcinoma cell line and its cisplatin-resistant form (A2780 and A2780cis), and non-cancerous human embryonic kidney (HEK293T) cells. To define the structure-activity relationships (SAR), the compounds have been compared with other Ru(II) and Os(II) complexes with curcuminoid ligands previously reported. SAR data reveal that the bisdemethoxycurcumin complexes are generally more active and selective than analogous curcumin-containing complexes.
Asunto(s)
Antineoplásicos , Complejos de Coordinación , Curcumina , Compuestos Organometálicos , Neoplasias Ováricas , Rutenio , Antineoplásicos/química , Línea Celular Tumoral , Complejos de Coordinación/química , Curcumina/química , Curcumina/farmacología , Diarilheptanoides/uso terapéutico , Ésteres , Femenino , Células HEK293 , Humanos , Ligandos , Compuestos Organometálicos/química , Osmio/química , Neoplasias Ováricas/tratamiento farmacológico , Ácido Palmítico/uso terapéutico , Rutenio/químicaRESUMEN
Being identified with less toxic and generally showing selective effects for solid tumor metastases, ruthenium and osmium compounds are promising drug candidates for clinical uses. Human serum proteins, such as albumin and transferrin, play vital roles in the transportation and accumulation of ruthenium and osmium agents into target tissues. However, the molecular mechanism of how transferrin transport ruthenium and their osmium analogues at atomic level remains obscure. In this study, we uncovered that the cellular uptake of Os3+ or Ru3+ are not competed by Fe3+. To unveil the molecular mechanism behind the phenomena, we report the first crystal structures of human serum transferrin (hTF) in complex with ruthenium and osmium compounds bound to the non-conserved residues on the surface of hTF without altering its overall conformation. As for Ru3+ and Os3+, these binding sites by descending affinity are: His14/His289, His349-350 ~ His578/Arg581. Ruthenium drugs and their osmium analogues preferentially bind to His14/His289 with bipyridine or imidazole ligands leaving. These binding sites on hTF surface are also available in human lactoferrin and some transferrin family member of other species. The presence of these binding sites makes the cellular uptake of Ru3+ and Os3+ less affected by Fe3+, compare to Zr4+ or Hf4+. Collectively, these findings are critical for our understanding of the role of serum transferrin in cellular delivery of ruthenium and osmium anticancer agents.
Asunto(s)
Rutenio , Sitios de Unión , Humanos , Modelos Moleculares , Osmio/química , Compuestos de Osmio/metabolismo , Rutenio/química , Transferrina/químicaRESUMEN
(1) Background: Ruthenium and osmium complexes attract increasing interest as next generation anticancer drugs. Focusing on structure-activity-relationships of this class of compounds, we report on 17 different ruthenium(II) complexes and four promising osmium(II) analogues with cinnamic acid derivatives as O,S bidentate ligands. The aim of this study was to determine the anticancer activity and the ability to evade platin resistance mechanisms for these compounds. (2) Methods: Structural characterizations and stability determinations have been carried out with standard techniques, including NMR spectroscopy and X-ray crystallography. All complexes and single ligands have been tested for cytotoxic activity on two ovarian cancer cell lines (A2780, SKOV3) and their cisplatin-resistant isogenic cell cultures, a lung carcinoma cell line (A549) as well as selected compounds on three non-cancerous cell cultures in vitro. FACS analyses and histone γH2AX staining were carried out for cell cycle distribution and cell death or DNA damage analyses, respectively. (3) Results: IC50 values show promising results, specifically a high cancer selective cytotoxicity and evasion of resistance mechanisms for Ru(II) and Os(II) compounds. Histone γH2AX foci and FACS experiments validated the high cytotoxicity but revealed diminished DNA damage-inducing activity and an absence of cell cycle disturbance thus pointing to another mode of action. (4) Conclusion: Ru(II) and Os(II) compounds with O,S-bidentate ligands show high cytotoxicity without strong effects on DNA damage and cell cycle, and this seems to be the basis to circumvent resistance mechanisms and for the high cancer cell specificity.
Asunto(s)
Antineoplásicos , Carcinoma , Cisplatino , Compuestos Organometálicos , Neoplasias Ováricas , Antineoplásicos/química , Antineoplásicos/farmacología , Línea Celular Tumoral , Cisplatino/farmacología , Complejos de Coordinación/química , Complejos de Coordinación/farmacología , Resistencia a Antineoplásicos , Femenino , Histonas , Humanos , Ligandos , Estructura Molecular , Compuestos Organometálicos/química , Compuestos Organometálicos/farmacología , Compuestos Organometálicos/uso terapéutico , Osmio/química , Osmio/farmacología , Neoplasias Ováricas/tratamiento farmacológico , Rutenio/química , Rutenio/farmacologíaRESUMEN
We report a new osmium(VI) nitrido complex bearing a nonplanar tetradentate ligand with potent anticancer activity. This complex causes mitochondrial damage, which induces liver cancer cell death via oncosis and apoptosis. This is the first osmium-based anticancer candidate that induces oncosis.
Asunto(s)
Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Complejos de Coordinación/farmacología , Mitocondrias/efectos de los fármacos , Nitrilos/farmacología , Osmio/farmacología , Antineoplásicos/química , Proliferación Celular/efectos de los fármacos , Complejos de Coordinación/química , Ensayos de Selección de Medicamentos Antitumorales , Células Hep G2 , Humanos , Mitocondrias/metabolismo , Estructura Molecular , Nitrilos/química , Osmio/químicaRESUMEN
With the aim of developing photostable near-infrared cell imaging probes, a convenient route to the synthesis of heteroleptic OsII complexes containing the Os(TAP)2 fragment is reported. This method was used to synthesize the dinuclear OsII complex, [{Os(TAP)2}2tpphz]4+ (where tpphz = tetrapyrido[3,2-a:2',3'-c:3â³,2''-h:2â´,3'''-j]phenazine and TAP = 1,4,5,8- tetraazaphenanthrene). Using a combination of resonance Raman and time-resolved absorption spectroscopy, as well as computational studies, the excited state dynamics of the new complex were dissected. These studies revealed that, although the complex has several close lying excited states, its near-infrared, NIR, emission (λmax = 780 nm) is due to a low-lying Os â TAP based 3MCLT state. Cell-based studies revealed that unlike its RuII analogue, the new complex is neither cytotoxic nor photocytotoxic. However, as it is highly photostable as well as live-cell permeant and displays NIR luminescence within the biological optical window, its properties make it an ideal probe for optical microscopy, demonstrated by its use as a super-resolution NIR STED probe for nuclear DNA.
Asunto(s)
Complejos de Coordinación/química , ADN/análisis , Sustancias Luminiscentes/química , Animales , Bovinos , Línea Celular Tumoral , Complejos de Coordinación/síntesis química , Complejos de Coordinación/toxicidad , Humanos , Sustancias Luminiscentes/síntesis química , Sustancias Luminiscentes/toxicidad , Microscopía Confocal , Osmio/química , Osmio/toxicidadRESUMEN
Trithiolato-bridged dinuclear ruthenium(II) complexes [Ru2(p-cym)2(SR)3]Cl (p-cym = p-cymene, R = benzyl derivatives) are regarded as the most cytotoxically potent metal(II) arene antineoplastics, but are oftentimes limited by their poor solubility in aqueous media. Thus, we designed bisphosphonate-functionalized ligands for use in a modular two-step complexation process to synthesize six trithiolato-bridged dinuclear ruthenium(II) and osmium(II) arene complexes bearing one to three bisphosphonate-benzylmercaptane derived ligands. In addition to improved aqueous solubility the high affinity of bisphosphonates towards apatite structures found in bone and bone metastases may grant selective targeting properties to functionalized organometallics. The complex stabilities and hydroxyapatite binding behavior were determined by UV/Vis spectroscopy. The bisphosphonate functionalization decreases antiproliferative activity in vitro, which was correlated to lower cellular accumulation, due to the different lipophilic profiles of the drug candidates.
Asunto(s)
Antineoplásicos/farmacología , Complejos de Coordinación/farmacología , Difosfonatos/farmacología , Antineoplásicos/síntesis química , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Complejos de Coordinación/síntesis química , Difosfonatos/síntesis química , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Ligandos , Osmio/química , Rutenio/química , Solubilidad , Agua/químicaRESUMEN
Extensive studies have laid the groundwork for understanding peroxidase-like nanozymes. However, improvements are still required before their practical applications. On one hand, it is significant to explore highly reactive nanozymes. On the other hand, it is necessary to avoid fouling formed on the surface of nanozymes, which will affect their activity and the results of H2O2 sensors or H2O2-related applications. Herein, a strategy is reported to design osmium nanoclusters (Os NCs) with the existence of bovine serum albumin (BSA) through biomineralization. BSA-Os NCs were found to possess intrinsic peroxidase-like activity with a high specific activity (6120 U/g). Studies also found that the catalytic activity of BSA-Os NCs was better than those of reported protein-assisted metal nanozymes (e.g., BSA-Pt NPs and BSA-Au NCs). More significantly, BSA has been confirmed as a protective shell to give Os NCs extrinsic antifouling property in some typical ions (e.g., Hg2+, Ag+, Pb2+, I-, Cr6+, Cu2+, Ce3+, S2-, etc.), saline (0-2 M), or protein (0-100 mg/mL) conditions. Under optimal conditions, a colorimetric sensor was established to realize a linear range of H2O2 from 1.25 to 200 µM with a low detection limit of 300 nM. On this basis, remarkable features enable a BSA-Os NCs-based colorimetric sensor to detect H2O2 from complex systems with clear color gradients. Together, this work highlights the advantages of protein-assisted Os nanozymes and provides a paragon for peroxidase-like nanozymes in H2O2-related applications.
Asunto(s)
Peróxido de Hidrógeno/análisis , Nanopartículas del Metal/química , Albúmina Sérica Bovina/química , Animales , Catálisis , Bovinos , Colorimetría/métodos , Peróxido de Hidrógeno/química , Límite de Detección , Osmio/química , Oxidación-ReducciónRESUMEN
Although nanoparticles based on Group 8 elements such as Fe and Ru have been developed, not much is known about Os nanoparticles. However, Os-based nanostructures might have potential in various applications including biomedical fields. Therefore, in this study, we synthesized Os-Te nanorods (OsTeNRs) by solvothermal galvanic replacement with Te nanotemplates. We explored the nanozymatic activity of the synthesized OsTeNRs and found that they exhibited superior photothermal conversion and photocatalytic activity. Along with chemotherapy (regorafenib) and immunotherapy, the nanozymatic, photothermal, and photodynamic activities of OsTeNRs were harnessed to develop a pentamodal treatment for hepatocellular carcinoma (HCC); in vitro and in vivo studies demonstrated that the pentamodal therapy could alleviate hypoxia in HCC cells by generating oxygen and reduced unintended drug accumulation in organs. Moreover, bone-marrow toxicity due to regorafenib could be reduced as the drug was released in a sustained manner. Thus, OsTeNRs can be considered as suitable nanotemplates for combinatorial cancer therapy.
Asunto(s)
Antineoplásicos/uso terapéutico , Carcinoma Hepatocelular/tratamiento farmacológico , Portadores de Fármacos/química , Neoplasias Hepáticas/tratamiento farmacológico , Nanotubos/química , Animales , Catálisis , Línea Celular Tumoral , Portadores de Fármacos/síntesis química , Portadores de Fármacos/efectos de la radiación , Masculino , Ratones Endogámicos C57BL , Nanotubos/efectos de la radiación , Osmio/química , Osmio/efectos de la radiación , Compuestos de Fenilurea/uso terapéutico , Fotoquimioterapia , Piridinas/uso terapéutico , Telurio/química , Telurio/efectos de la radiación , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
We report the synthesis of the organo-osmium anticancer complex [Os(η6-p-cym)(N,N-azpy-NMe2)Br]PF6 (1) containing natural abundance 187Os (1.96%), and isotopically-enriched (98%) [187Os]-1. Complex 1 and [187Os]-1 contain a π-bonded para-cymene (p-cym), a chelated 4-(2-pyridylazo)-N,N-dimethylaniline (azpy-NMe2), and a monodentate bromide as ligands. The X-ray crystal structure of 1 confirmed its half-sandwich 'piano-stool' configuration. Complex 1 is a member of a family of potent anticancer complexes, and exhibits sub-micromolar activity against A2780 human ovarian cancer cells (IC50 = 0.40 µM). Complex [187Os]-1 was analysed by high-resolution ESI-MS, 1D 1H and 13C NMR, and 2D 1H COSY, 13C-1H HMQC, and 1H-187Os HMBC NMR spectroscopy. Couplings of 1H and 13C nuclei from the azpy/p-cym ligands to 187Os were observed with J-couplings (1J to 4J) ranging between 0.6-8.0 Hz. The 187Os chemical shift of [187Os]-1 (-4671.3 ppm, determined by 2D 1H-187Os HMBC NMR) is discussed in relation to the range of values reported for related Os(II) arene and cyclopentadienyl complexes (-2000 to -5200 ppm).
Asunto(s)
Antineoplásicos/química , Antineoplásicos/farmacología , Compuestos Organometálicos/química , Compuestos Organometálicos/farmacología , Osmio/farmacología , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Femenino , Humanos , Espectroscopía de Resonancia Magnética , Modelos Moleculares , Estructura Molecular , Osmio/química , Neoplasias Ováricas/tratamiento farmacológicoRESUMEN
Metal complexes have been used to treat cancer since the discovery of cisplatin and its interaction with DNA in the 1960's. Facing the resistance mechanisms against platinum salts and their side effects, safer therapeutic approaches have been sought through other metals, including ruthenium. In the early 2000s, Michel Pfeffer and his collaborators started to investigate the biological activity of organo-ruthenium/osmium complexes, demonstrating their ability to interfere with the activity of purified redox enzymes. Then, they discovered that these organo-ruthenium/osmium complexes could act independently of DNA damage and bypass the requirement for the tumor suppressor gene TP53 to induce the endoplasmic reticulum (ER) stress pathway, which is an original cell death pathway. They showed that other types of ruthenium complexes-as well complexes with other metals (osmium, iron, platinum)-can induce this pathway as well. They also demonstrated that ruthenium complexes accumulate in the ER after entering the cell using passive and active mechanisms. These particular physico-chemical properties of the organometallic complexes designed by Dr. Pfeffer contribute to their ability to reduce tumor growth and angiogenesis. Taken together, the pioneering work of Dr. Michel Pfeffer over his career provides us with a legacy that we have yet to fully embrace.
Asunto(s)
Antineoplásicos/farmacología , Resistencia a Antineoplásicos , Estrés del Retículo Endoplásmico/efectos de los fármacos , Compuestos Organometálicos/farmacología , Animales , Antineoplásicos/química , Humanos , Compuestos Organometálicos/química , Osmio/química , Rutenio/químicaRESUMEN
Half-sandwich Os-arene complexes exhibit promising anticancer activity, but their photochemistry has hardly been explored. To exploit the photocytotoxicity and photochemistry of Os-arenes, O,O-chelated complexes [Os(η6-p-cymene)(Curc)Cl] (OsCUR-1, Curc = curcumin) and [Os(η6-biphenyl)(Curc)Cl] (OsCUR-2), and N,N-chelated complexes [Os(η6-biphenyl)(dpq)I]PF6 (OsDPQ-2, dpq = pyrazino[2,3-f][1,10]phenanthroline) and [Os(η6-biphenyl)(bpy)I]PF6 (OsBPY-2, bpy = 2,2'-bipyridine), have been investigated. The Os-arene curcumin complexes showed remarkable photocytotoxicity toward a range of cancer cell lines (blue light IC50: 2.6-5.8 µM, photocytotoxicity index PI = 23-34), especially toward cisplatin-resistant cancer cells, but were nontoxic to normal cells. They localized mainly in mitochondria in the dark but translocated to the nucleus upon photoirradiation, generating DNA and mitochondrial damage, which might contribute toward overcoming cisplatin resistance. Mitochondrial damage, apoptosis, ROS generation, DNA damage, angiogenesis inhibition, and colony formation were observed when A549 lung cancer cells were treated with OsCUR-2. The photochemistry of these Os-arene complexes was investigated by a combination of NMR, HPLC-MS, high energy resolution fluorescence detected (HERFD), X-ray adsorption near edge structure (XANES) spectroscopy, total fluorescence yield (TFY) XANES spectra, and theoretical computation. Selective photodissociation of the arene ligand and oxidation of Os(II) to Os(III) occurred under blue light or UVA excitation. This new approach to the design of novel Os-arene complexes as phototherapeutic agents suggests that the novel curcumin complex OsCUR-2, in particular, is a potential candidate for further development as a photosensitizer for anticancer photoactivated chemotherapy (PACT).
Asunto(s)
Antineoplásicos/farmacología , Calixarenos/farmacología , Complejos de Coordinación/farmacología , Osmio/farmacología , Células A549 , Antineoplásicos/síntesis química , Antineoplásicos/química , Apoptosis/efectos de los fármacos , Calixarenos/química , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Complejos de Coordinación/síntesis química , Complejos de Coordinación/química , Daño del ADN , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Estructura Molecular , Osmio/química , Procesos FotoquímicosRESUMEN
Ruthenium (Ru) and osmium (Os) complexes are of sustained interest in cancer research and may be alternative to platinum-based therapy. We detail here three new series of ruthenium and osmium complexes, supported by physico-chemical characterizations, including time-dependent density functional theory, a combined experimental and computational study on the aquation reactions and the nature of the metal-arene bond. Cytotoxic profiles were then evaluated on several cancer cell lines although with limited success. Further investigations were, however, performed on the most active series using a genetic approach based on RNA interference and highlighted a potential multi-target mechanism of action through topoisomerase II, mitotic spindle, HDAC and DNMT inhibition.
Asunto(s)
Antineoplásicos/farmacología , Biotina/farmacología , Complejos de Coordinación/farmacología , Morfolinas/farmacología , Osmio/farmacología , Rutenio/farmacología , Animales , Antineoplásicos/síntesis química , Antineoplásicos/química , Biotina/química , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Complejos de Coordinación/síntesis química , Complejos de Coordinación/química , Cristalografía por Rayos X , Teoría Funcional de la Densidad , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Ratones , Modelos Moleculares , Estructura Molecular , Morfolinas/química , Osmio/química , Rutenio/químicaRESUMEN
The preparation of two polyarginine conjugates of the complex Os(II) [bis-(4'-(4-carboxyphenyl)-2,2':6',2â³-terpyridine)] [Os-(Rn)2]x+ (n = 4 and 8; x = 10 and 18) is reported, to explore whether the R8 peptide sequence that promotes cell uptake requires a contiguous amino acid sequence for membrane permeation or if this can be accomplished in a linearly bridged structure with the additive effect of shorter peptide sequences. The conjugates exhibit NIR emission centered at 754 nm and essentially oxygen-insensitive emission with a lifetime of 89 ns in phosphate-buffered saline. The uptake, distribution, and cytotoxicity of the parent complex and peptide derivatives were compared in 2D cell monolayers and a three-dimensional (3D) multicellular tumor spheroid (MCTS) model. Whereas, the bis-octaarginine sequences were impermeable to cells and spheroids, and the bis-tetraarginine conjugate showed excellent cellular uptake and accumulation in two 2D monolayer cell lines and remarkable in-depth penetration of 3D MCTSs of pancreatic cancer cells. Overall, the data indicates that cell permeability can be promoted via non-contiguous sequences of arginine residues bridged across the metal centre.
Asunto(s)
Antineoplásicos/farmacología , Complejos de Coordinación/farmacología , Osmio/farmacología , Péptidos/farmacología , Esferoides Celulares/efectos de los fármacos , Animales , Antineoplásicos/síntesis química , Antineoplásicos/química , Permeabilidad de la Membrana Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Complejos de Coordinación/síntesis química , Complejos de Coordinación/química , Cricetulus , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Estructura Molecular , Imagen Óptica , Osmio/química , Péptidos/químicaRESUMEN
Resonant X-ray emission spectroscopy (RXES) has developed in the past decade as a powerful tool to probe the chemical state of a metal center and in situ study chemical reactions. We have used it to monitor spectral changes associated with the reduction of osmium(VI) nitrido complexes to the osmium(III) ammine state by the biologically relevant reducing agent, glutathione. RXES difference maps are consistent with the proposed DFT mechanism and the formation of two stable osmium(IV) intermediates, thereby supporting the overall pathway for the reduction of these high-valent anticancer metal complexes for which reduction by thiols within cells may be essential to the antiproliferative activity.
Asunto(s)
Antineoplásicos/química , Complejos de Coordinación/química , Teoría Funcional de la Densidad , Osmio/química , Antineoplásicos/síntesis química , Complejos de Coordinación/síntesis química , Estructura Molecular , Oxidación-Reducción , Espectrometría por Rayos XRESUMEN
The treatment of tuberculosis (TB) poses a major challenge as frontline therapeutic agents become increasingly ineffective with the emergence and spread of drug-resistant strains of Mycobacterium tuberculosis (Mtb). To combat this global health problem, new antitubercular agents with novel modes of action are needed. We have screened a close family of 17 organometallic half-sandwich Os(II) complexes [(arene)Os(phenyl-azo/imino-pyridine)(Cl/I)]+Y- containing various arenes (p-cymene, biphenyl, or terphenyl), and NMe2, F, Cl, or Br phenyl or pyridyl substituents, for activity towards Mtb in comparison with normal human lung cells (MRC5). In general, complexes with a monodentate iodido ligand were more potent than chlorido complexes, and the five most potent iodido complexes (MIC 1.25-2.5 µM) have an electron-donating Me2N or OH substituent on the phenyl ring. As expected, the counter anion Y (PF6-, Cl-, I-) had little effect on the activity. The pattern of potency of the complexes towards Mtb is similar to that towards human cells, perhaps because in both cases intracellular thiols are likely to be involved in their activation and their redox mechanism of action. The most active complex against Mtb is the p-cymene Os(II) NMe2-phenyl-azopyridine iodido complex (2), a relatively inert complex that also exhibits potent activity towards cancer cells. The uptake of Os from complex 2 by Mtb is rapid and peaks after 6 h, with temperature-dependence studies suggesting a major role for active transport. Significance to Metallomics Antimicrobial resistance is a global health problem. New advances are urgently needed in the discovery of new antibiotics with novel mechanisms of action. Half-sandwich organometallic complexes offer a versatile platform for drug design. We show that with an appropriate choice of the arene, an N,N-chelated ligand, and monodentate ligand, half-sandwich organo-osmium(II) complexes can exhibit potent activity towards Mycobacterium tuberculosis (Mtb), the leading cause of death from a single infectious agent. The patterns of activity of the 17 azo- and imino-pyridine complexes studied here towards Mtb and normal lung cells suggest a common redox mechanism of action involving intracellular thiols.