ABSTRACT
[Cu(thp)4]PF6, [Cu(PTA)4]PF6, [Au(thp)4]PF6 and [Au(PTA)4]PF6 are phosphane (thp = tris(hydroxymethyl)phosphane; PTA = 1,3,5-triaza-7-phosphaadamantane) copper(I) and gold(I) water-soluble complexes characterized by high anticancer activity in a wide range of solid tumors, often able to overcome drug resistance of platinum-based compounds. For these reasons, they have been proposed as a valid alternative to platinum-based chemotherapeutic drugs (e.g., cisplatin and oxaliplatin). In vitro experiments performed on organotypic cultures of dorsal root ganglia (DRG) from 15-day-old rat embryos revealed that copper-based compounds were not neurotoxic even at concentrations higher than the IC50 obtained in human cancer cells while [Au(PTA)4]PF6 was neurotoxic at lower concentration than IC50 in cancer cell lines. The ability of these compounds to hinder the proteasome machinery in DRG neurons was tested by fluorimetric assay showing that the non-neurotoxic copper-based complexes do not inhibit proteasome activity in DRG primary neuron cultures. On the contrary, the neurotoxic complex [Au(PTA)4]PF6, induced a significant inhibition of proteasome activity even at concentrations lower than the IC50 in cancer cells. The proteasome inhibition induced by [Au(PTA)4]PF6 was associated with a significant increase in α-tubulin polymerization that was not observed following the treatment with copper-based compounds. Uptake experiments performed by atomic absorption spectrometry showed that both copper-based complexes and [Au(PTA)4]PF6 are internalized in neuron cultures. In vitro and in vivo preliminary data confirmed copper-based complexes as the most promising compounds, not only for their anticancer activity but also concerning the peripheral neurotoxicity profile.
Subject(s)
Adamantane/analogs & derivatives , Antineoplastic Agents/pharmacology , Neurons/drug effects , Organophosphorus Compounds/chemistry , Organophosphorus Compounds/pharmacology , Action Potentials/drug effects , Adamantane/chemistry , Adamantane/pharmacology , Animals , Antineoplastic Agents/chemistry , Bortezomib/pharmacology , Carcinoma/pathology , Cell Line, Tumor , Cells, Cultured , Cisplatin/pharmacology , Copper/metabolism , Dose-Response Relationship, Drug , Embryo, Mammalian , Female , Ganglia, Spinal/cytology , Gold/metabolism , Humans , Mice , Mice, Inbred C57BL , Neuronal Outgrowth/radiation effects , Peripheral Nerves/drug effects , Peripheral Nerves/physiology , Polymerization/drug effects , Proteasome Endopeptidase Complex/metabolism , Rats , Rats, Sprague-Dawley , Tubulin/metabolismABSTRACT
A new Cu-based anticancer metallodrug which targets the translocator protein is reported. [CuBr2(TZ6)] elicits a remarkable in vitro cytotoxicity in sensitive and multidrug resistant cell lines and induces a 98% reduction of tumor mass in a murine tumor model. Target binding was studied by experimental and computational methods.
Subject(s)
Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Copper/chemistry , Molecular Targeted Therapy , Organometallic Compounds/chemistry , Organometallic Compounds/pharmacology , Receptors, GABA/metabolism , Animals , Antineoplastic Agents/metabolism , Cell Line, Tumor , Gene Expression Regulation, Neoplastic/drug effects , Humans , Mice , Models, Molecular , Organometallic Compounds/metabolism , Protein Conformation , Receptors, GABA/chemistry , Xenograft Model Antitumor AssaysABSTRACT
The novel NHC ligand precursor 1,4-bis(4-nitrobenzyl)-1H-1,2,4-triazol-4-ium bromide, [HTz((pNO2Bz)2)]Br, has been synthesized and used in the synthesis of the corresponding metal complexes M[Tz((pNO2Bz)2)]Br (M = Cu(I), Ag(I) or Au(I)). These compounds were characterized by several spectroscopic techniques including NMR and mass spectroscopy. The complete series of Au(I), Ag(I) and Cu(I) 1,2,4-triazole based NHC complexes has been synthesized aiming at a SAR study and at identifying the primary cellular targets accounting for their cytotoxic action. The cytotoxic properties of the NHC complexes have been assessed in various human cancer cell lines, including cisplatin sensitive and resistant cells, the most efficacious antiproliferative compound being Cu(I)-NHC, which was able to promote a growth inhibitory effect up to ten times higher than that promoted by cisplatin. A detailed analysis of molecular and cellular pharmacology allowed us to elucidate the role of the metallic core in determining the biological properties. In particular, gold(I) and silver(I) NHC complexes were found to be able to hamper mammalian thioredoxin reductase (TrxR) activity in human A431 cervical cancer cells, ultimately leading to a dramatic alteration of the cellular redox state and to the induction of cell death via apoptosis. Conversely, the copper NHC complex was found to be capable of inhibiting proteasome functionality thus determining the induction of a non-apoptotic cell death pathway.
Subject(s)
Coordination Complexes/chemistry , Heterocyclic Compounds/chemistry , Methane/analogs & derivatives , Triazoles/chemistry , Apoptosis/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , Coordination Complexes/chemical synthesis , Coordination Complexes/toxicity , Copper/chemistry , Gold/chemistry , Humans , Ligands , Methane/chemistry , Microscopy, Electron, Transmission , Oxidation-Reduction , Proteasome Endopeptidase Complex/chemistry , Proteasome Endopeptidase Complex/metabolism , Reactive Oxygen Species/metabolism , Silver/chemistry , Thioredoxin-Disulfide Reductase/antagonists & inhibitors , Thioredoxin-Disulfide Reductase/metabolismABSTRACT
Homoleptic, tetrahedral Cu(i) complexes of the type [Cu(P)4]BF4 (1-3), where P are the phosphine ligands, 1,3,5-triaza-7-phosphaadamantane (PTA), 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane (DAPTA) and 2-thia-1,3,5-triaza-phosphoaadamantane-2,2-dioxide (PTA-SO2), have been prepared. Novel complexes [Cu(DAPTA)4]BF42 and [Cu(PTA-SO2)4]BF43 have been fully characterized by means of spectroscopic methods, corroborated by XAS-EXAFS analysis of 2. In vitro cell culture experiments revealed a significant antiproliferative activity for Cu(i) compounds against several human cancer cell lines derived from solid tumors with preferential cell growth inhibition towards tumour compared to non-malignant cells. In vitro monitoring of migration and capillary-like tube formation of human umbilical vein endothelial cells (HUVECs) showed an anti-angiogenic effect of copper(i) complexes at sub-cytotoxic concentrations. In vivo studies on the antitumor efficacy and ability to inhibit angiogenesis confirmed the dual cytotoxic and anti-angiogenic properties of Cu(i) derivatives.
Subject(s)
Angiogenesis Inhibitors/pharmacology , Antineoplastic Agents/pharmacology , Cell Proliferation/drug effects , Coordination Complexes/pharmacology , Copper/pharmacology , Phosphines/pharmacology , Adamantane/analogs & derivatives , Angiogenesis Inhibitors/chemistry , Angiogenesis Inhibitors/toxicity , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/toxicity , Body Weight/drug effects , Cell Line, Tumor , Coordination Complexes/chemistry , Coordination Complexes/toxicity , Copper/chemistry , Copper/toxicity , Female , Human Umbilical Vein Endothelial Cells , Humans , Male , Mice , Mice, Inbred C57BL , Neovascularization, Pathologic/chemically induced , Organophosphorus Compounds , Phosphines/chemistry , Phosphines/toxicityABSTRACT
The ShcA adaptor protein is engaged by numerous receptor tyrosine kinases (RTKs) in breast cancer cells. Once activated, RTKs phosphorylate three key tyrosine phosphorylation sites (Y239, Y240 and Y317) within ShcA that creates a docking site for Grb2/SOS and Grb2/Gab-containing complexes to activate the MAPK and AKT signaling pathways, respectively. We previously demonstrated that a tyrosine to phenylalanine substitution of the ShcA tyrosine phosphorylation sites (Shc3F-Y239/240/313F) significantly impairs breast tumor growth and angiogenesis in transgenic mouse models, in part, through the regulation of vascular endothelial growth factor (VEGF) production. Despite this fact, the underlying molecular mechanisms by which ShcA transduces pro-tumorigenic signals in breast cancer cells remain poorly defined. In this study, we demonstrate that ShcA-dependent activation of AKT, but not the RAS/MAPK pathway, induces VEGF production by bolstering VEGF mRNA translation. Accordingly, ShcA drives breast tumor growth and angiogenesis in vivo in a 4E-BP-dependent manner. These findings establish ShcA as a biological bridge that links AKT activation downstream of RTKs to cap-dependent VEGF mRNA translation in order to promote mammary tumorigenesis.
