RESUMEN
Among organic-inorganic hybrid molecules consisting of organic structure(s) and metal(s), only few studies are available on the cytotoxicity of nucleophilic molecules. In the present study, we investigated the cytotoxicity of a nucleophilic organotellurium compound, diphenyl ditelluride (DPDTe), using a cell culture system. DPDTe exhibited strong cytotoxicity against vascular endothelial cells and fibroblasts along with high intracellular accumulation but showed no cytotoxicity and had less accumulation in vascular smooth muscle cells and renal epithelial cells. The cytotoxicity of DPDTe decreased when intramolecular tellurium atoms were replaced with selenium or sulfur atoms. Electronic state analysis revealed that the electron density between tellurium atoms in DPDTe was much lower than those between selenium atoms of diphenyl diselenide and sulfur atoms of diphenyl disulfide. Moreover, diphenyl telluride did not accumulate and exhibit cytotoxicity. The cytotoxicity of DPDTe was also affected by substitution. p-Dimethoxy-DPDTe showed higher cytotoxicity, but p-dichloro-DPDTe and p-methyl-DPDTe showed lower cytotoxicity than that of DPDTe. The subcellular distribution of the compounds revealed that the compounds with stronger cytotoxicity showed higher accumulation rates in the mitochondria. Our findings suggest that the electronic state of tellurium atoms in DPDTe play an important role in accumulation and distribution of DPDTe in cultured cells. The present study supports the hypothesis that nucleophilic organometallic compounds, as well as electrophilic organometallic compounds, exhibit cytotoxicity by particular mechanisms.
Asunto(s)
Derivados del Benceno/farmacología , Células Endoteliales/efectos de los fármacos , Compuestos Organometálicos/farmacología , Compuestos de Organoselenio/farmacología , Telurio/farmacología , Animales , Derivados del Benceno/química , Derivados del Benceno/metabolismo , Bovinos , Línea Celular , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Células Endoteliales/citología , Células Endoteliales/metabolismo , Células Epiteliales/citología , Células Epiteliales/efectos de los fármacos , Células Epiteliales/metabolismo , Fibroblastos/citología , Fibroblastos/efectos de los fármacos , Fibroblastos/metabolismo , Humanos , Células LLC-PK1 , Modelos Químicos , Estructura Molecular , Miocitos del Músculo Liso/citología , Miocitos del Músculo Liso/efectos de los fármacos , Miocitos del Músculo Liso/metabolismo , Compuestos Organometálicos/química , Compuestos Organometálicos/metabolismo , Compuestos de Organoselenio/química , Compuestos de Organoselenio/metabolismo , Porcinos , Telurio/químicaRESUMEN
The complex [99m Tc(OH2 )3 (CO)3 ]+ has become a versatile building block in radiopharmaceutical chemistry, applied by many groups worldwide. However, despite widespread efforts, only one compound has made it right the way through clinical trials. Along the way from its discovery to its development into an eventual product, the author experienced issues that he would handle differently in retrospect. In this article, these experiences are turned into "lessons" that might be helpful for young researchers finding themselves in similar situations. Beside issues with patenting and company strategies, the carbonyl story has provided scientific implications beyond its own story, and insights from which any future 99m Tc-based chemistry for radiopharmacy or molecular imaging might benefit.
Asunto(s)
Complejos de Coordinación/química , Radiofármacos/química , Tecnecio/química , Complejos de Coordinación/síntesis química , Desarrollo de Medicamentos , Humanos , Estructura Molecular , Radiofármacos/síntesis química , InvestigadoresRESUMEN
As toxic substances can enter the circulating blood and cross endothelial monolayers to reach parenchymal cells in organs, vascular endothelial cells are an important target compartment for such substances. Reactive sulfur species protect cells against oxidative stress and toxic substances, including heavy metals. Reactive sulfur species are produced by enzymes, such as cystathionine γ-lyase (CSE), cystathionine ß-synthase, 3-mercaptopyruvate sulfurtransferase, and cysteinyl-tRNA synthetase. However, little is known about the regulatory mechanisms underlying the expression of these enzymes in vascular endothelial cells. Bio-organometallics is a research field that analyzes biological systems using organic-inorganic hybrid molecules (organometallic compounds and metal coordinating compounds) as molecular probes. In the present study, we analyzed intracellular signaling pathways that mediate the expression of reactive sulfur species-producing enzymes in cultured bovine aortic endothelial cells, using copper diethyldithiocarbamate (Cu10). Cu10 selectively upregulated CSE gene expression in vascular endothelial cells independent of cell density. This transcriptional induction of endothelial CSE required both the diethyldithiocarbamate scaffold and the coordinated copper ion. Additionally, the present study revealed that ERK1/2, p38 MAPK, and hypoxia-inducible factor (HIF)-1α/HIF-1ß pathways mediate transcriptional induction of endothelial CSE by Cu10. The transcription factors NF-κB, Sp1, and ATF4 were suggested to act in constitutive CSE expression, although the possibility that they are involved in the CSE induction by Cu10 cannot be excluded. The present study used a copper complex as a molecular probe to reveal that the transcription of CSE is regulated by multiple pathways in vascular endothelial cells, including ERK1/2, p38 MAPK, and HIF-1α/HIF-1ß. Bio-organometallics appears to be an effective strategy for analyzing the functions of intracellular signaling pathways in vascular endothelial cells.
Asunto(s)
Cistationina gamma-Liasa/genética , Ditiocarba/farmacología , Animales , Translocador Nuclear del Receptor de Aril Hidrocarburo/genética , Translocador Nuclear del Receptor de Aril Hidrocarburo/metabolismo , Bovinos , Células Cultivadas , Cobre/química , Cistationina gamma-Liasa/metabolismo , Ditiocarba/química , Células Endoteliales/efectos de los fármacos , Células Endoteliales/metabolismo , Endotelio Vascular/citología , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Azufre/metabolismoRESUMEN
The design and first enantioselective synthesis of a series of chiral ferrocifens and ferrociphenols was realised by enantioselective palladium-catalysed intramolecular direct C-H bond activation followed by McMurry coupling. Biological evaluation revealed moderate anticancer activities on breast cancer cells and evidence of chiral discrimination between enantiomers. Treatment of the novel ferrocifens with Ag2 O revealed that these systems are unable to form a neutral quinone methide, yet still demonstrate marked antiproliferative properties against both the hormone-dependent MCF-7 and hormone-independent MDA-MB-231 cell lines. This bioactivity arises from two mechanisms: Fenton-type chemistry and the anti-estrogenic activity associated with the tamoxifen-like structure.
Asunto(s)
Antineoplásicos/farmacología , Neoplasias de la Mama/tratamiento farmacológico , Compuestos Ferrosos/farmacología , Antineoplásicos/síntesis química , Antineoplásicos/química , Neoplasias de la Mama/patología , Catálisis , Proliferación Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Femenino , Compuestos Ferrosos/síntesis química , Compuestos Ferrosos/química , Humanos , Estructura Molecular , Paladio/química , Estereoisomerismo , Relación Estructura-Actividad , Células Tumorales CultivadasRESUMEN
As the field of utilization of organic-inorganic hybrid molecules expands, the toxicology of these compounds is becoming more important. We have shown previously that there is a strong correlation between cytotoxicity and intracellular accumulation detected as metal content, which is modulated by the substituents, of organic-inorganic hybrid molecules. In this study, we investigated the cytotoxicity of pentavalent organoantimony compounds with three phenyl groups on cultured vascular endothelial cells. The results indicated that the cytotoxicity of pentavalent organoantimony compounds was not correlated with the hydrophobicity and intracellular accumulation of these compounds. Therefore, we suggest that hydrophobicity and intracellular accumulation are not necessarily predictive of cytotoxicity in organic-inorganic hybrid molecules.
Asunto(s)
Antimonio/toxicidad , Células Endoteliales/efectos de los fármacos , Espacio Intracelular/metabolismo , Compuestos Organometálicos/toxicidad , Animales , Antimonio/química , Antimonio/metabolismo , Bovinos , Técnicas de Cultivo de Célula , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Células Endoteliales/metabolismo , Espacio Intracelular/efectos de los fármacos , Estructura Molecular , Compuestos Organometálicos/química , Compuestos Organometálicos/metabolismo , Relación Estructura-ActividadRESUMEN
Although cytotoxicity of inorganic metals has been well investigated, little is known about the cytotoxicity of organic-inorganic hybrid molecules. The cytotoxicity of zinc complexes was evaluated using a culture system of vascular endothelial cells. We found that bis(1,4-dihydro-2-methyl-1-phenyl-4-thioxo-3-pyridiolato)zinc(II), termed Zn-06, exhibited strong cytotoxicity in vascular smooth muscle cells, epithelial cells, fibroblastic cells, and vascular endothelial cells. This study showed that the tetracoordinate structure of the Zn-06 molecule, which contains two sulfur and two oxygen atoms attached to the zinc atom, facilitated its accumulation within vascular endothelial cells whereas the whole structure of the zinc complex was involved in its cytotoxicity in the cells. The present data suggest that a part of the structure, especially the binding site of the metal atom, was responsible for accumulation of zinc complexes, and the entire structure is responsible for their cytotoxicity in vascular endothelial cells.
Asunto(s)
Células Endoteliales/efectos de los fármacos , Compuestos de Zinc/toxicidad , Animales , Bovinos , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Células Epiteliales/efectos de los fármacos , Fibroblastos/efectos de los fármacos , Humanos , Miocitos del Músculo Liso/efectos de los fármacos , PorcinosRESUMEN
It has been well established that organic-inorganic hybrid molecules can exhibit biological activities that are different from those of either their intramolecular metals in inorganic forms or their organic structures. We have previously reported that organoantimony compound Sb-phenyl-N-methyl-5,6,7,12-tetrahydrodibenz[c,f][1,5]azastibocine (PMTAS) is nontoxic, but that the compound exhibits cytotoxicity in vascular endothelial cells when the antimony atom is replaced with a bismuth atom. In the present study, we investigated the cytotoxicity and intracellular accumulation of PMTAS and its analogs and found that the cytotoxicity of PMTAS analogs also decrease depending on the electron-withdrawing property of the substituent bound to the intramolecular antimony atom. On the other hand, with the exception of the phenyl group, and depending on the carbon number of hydrocarbon group bound to the intramolecular nitrogen atom, cytotoxicity was enhanced. Furthermore, the cytotoxicity of PMTAS analogs correlated with their intracellular accumulation values. These results suggested that the low cytotoxicity effects of PMTAS on vascular endothelial cells is due to the characteristics of substituents bound to intramolecular antimony and nitrogen atoms.
Asunto(s)
Antimonio/toxicidad , Células Endoteliales/efectos de los fármacos , Compuestos Organometálicos/toxicidad , Animales , Bovinos , Supervivencia Celular/efectos de los fármacos , Compuestos Organometálicos/química , Relación Estructura-ActividadRESUMEN
Organic-inorganic hybrid molecules, which are composed of organic-ligand(s) and metal(s), are indispensable as synthetic reagents in chemistry, but they have made very little in the way of contributions to biological research. Previously, we reported that the cytotoxicity of organic-inorganic hybrid molecules in vascular endothelial cells depends on interactions between the intramolecular metal and ligand, but remains independent of the hydrophobicity of the intramolecular metal(s). Herein, we show a synergistic cytotoxicity produced by forming a complex of copper and 2,9-dimethyl-1,10-phenanthroline in vascular endothelial cells that depends on the intracellular accumulation of copper.
Asunto(s)
Complejos de Coordinación/toxicidad , Cobre/toxicidad , Células Endoteliales/efectos de los fármacos , Ligandos , Compuestos Organometálicos/toxicidad , Fenantrolinas/toxicidad , Animales , Bovinos , Células Cultivadas , Complejos de Coordinación/metabolismo , Cobre/metabolismo , Sinergismo Farmacológico , Células Endoteliales/metabolismo , Interacciones Hidrofóbicas e Hidrofílicas , Compuestos Organometálicos/metabolismo , Fenantrolinas/metabolismoRESUMEN
Vascular endothelial cells cover the luminal surface of blood vessels and contribute to the prevention of vascular disorders such as atherosclerosis. Metallothionein (MT) is a low molecular weight, cysteine-rich, metal-binding, inducible protein, which protects cells from the toxicity of heavy metals and active oxygen species. Endothelial MT is not induced by inorganic zinc. Adequate tools are required to investigate the mechanisms underlying endothelial MT induction. In the present study, we found that an organoantimony compound, tris(pentafluorophenyl)stibane, induces gene expression of MT-1A and MT-2A, which are subisoforms of MT in bovine aortic endothelial cells. The data reveal that MT-1A is induced by activation of both the MTF-1-MRE and Nrf2-ARE pathways, whereas MT-2A expression requires only activation of the MTF-1-MRE pathway. The present data suggest that the original role of MT-1 is to protect cells from heavy metal toxicity and oxidative stress in the biological defense system, while that of MT-2 is to regulate intracellular zinc metabolism.
Asunto(s)
Aorta/citología , Células Endoteliales/metabolismo , Hidrocarburos Clorados/farmacología , Metalotioneína/genética , Animales , Bovinos , Proteínas de Unión al ADN/genética , Células Endoteliales/efectos de los fármacos , Glutamato-Cisteína Ligasa/genética , Hemo-Oxigenasa 1/genética , Factor 2 Relacionado con NF-E2/genética , Isoformas de Proteínas/genética , Factores de Transcripción/genética , Transcripción Genética/efectos de los fármacos , Transcripción Genética/genética , Factor de Transcripción MTF-1RESUMEN
The interest in organic-inorganic hybrid molecules as molecular probes for biological systems has been growing rapidly. Such hybrid molecules exhibit unique biological activities. Herein, copper(II) bis(diethyldithiocarbamate) (Cu10) was found to activate the transcription factor NF-E2-related factor 2 (Nrf2), which is responsible for regulating antioxidant and phase II xenobiotic enzymes, in vascular endothelial cells. The copper complex rapidly accumulated within cells and induced nuclear translocation of Nrf2, leading to upregulation of the expression of downstream proteins without cytotoxic effects. However, while copper bis(2-hydroxyethyl)dithiocarbamate activated Nrf2, copper ion, diethyldithiocarbamate ligand with or without zinc or iron failed to exhibit this activity. Intracellular accumulation of Cu10 was higher than that of Cu(II) and Cu(I). While the accumulation of copper(II) bis(dimethyldithiocarbamate) was reduced by small interfering RNA (siRNA)-mediated knockdown of the copper transporter CTR1, the knockdown did not affect Cu10 accumulation, indicating that Cu10 rapidly enters vascular endothelial cells via CTR1-independent mechanisms. In addition, copper and iron complexes with other ligands tested could not activate Nrf2, suggesting that the intramolecular interaction between copper and dithiocarbamate ligand is important for the activation of the transcription factor. Cu10 induced the expression of heme oxygenase-1, NAD(P)H quinone oxidoreductase 1, and γ-glutamylcysteine synthetase, downstream proteins of Nrf2. It was suggested that Cu10-induced activation of Nrf2 was due to proteasome inhibition as well as binding to Kelch-like ECH-associated protein 1. Since the effects of Cu10 on vascular endothelial cells are unique and diverse, the copper complex may be a good molecular probe to analyze the functions of the cells.