Copper(I) targeting in the Alzheimer's disease context: a first example using the biocompatible PTA ligand

Rationally Designed Cu(I) Ligand to Prevent CuAβ-Generated ROS Production in the Alzheimer's Disease Context

In the context of Alzheimer's disease, copper (Cu) can be loosely bound to the amyloid-β (Aβ) peptide, leading to the formation of CuAβ, which can catalytically generate reactive oxygen species that contribute to oxidative stress. To fight against this phenomenon, the chelation therapy approach has been developed and consists of using a ligand able to remove Cu from Aβ and to redox-silence it, thus stopping the reactive oxygen species (ROS) production. A large number of Cu(II) chelators has been studied, allowing us to define and refine the properties required to design a "good" ligand, but without strong therapeutic outcomes to date. Those chelators targeted the Cu(II) redox state. Herein, we explore a parallel and relevant alternative pathway by designing a chelator able to target the Cu(I) redox state. To that end, we designed LH2 ([1N3S] binding set) and demonstrated that (i) it is perfectly able to extract Cu(I) from Cu(I)Aβ even in the presence of an excess of Zn(II) and (ii) it redox-silences the Cu, preventing the formation of ROS. We showed that LH2 that is sensitive to oxidation can efficiently replace the [Zn(II)L] complex without losing its excellent ability to stop the ROS production while increasing its resistance to oxidation.

Ability of Azathiacyclen Ligands To Stop Cu(Aβ)-Induced Production of Reactive Oxygen Species: [3N1S] Is the Right Donor Set

Alzheimer's disease (AD) is an incurable neurodegenerative disease that leads to the progressive and irreversible loss of mental functions. The amyloid beta (Aβ) peptide involved in the disease is responsible for the production of damaging reactive oxygen species (ROS) when bound to Cu ions. A therapeutic approach that consists of removing Cu ions from Aβ to alter this deleterious interaction is currently being developed. In this context, we report the ability of five different 12-membered thiaazacyclen ligands to capture Cu from Aβ and to redox silence it. We propose that the presence of a sole sulfur atom in the ligand increases the rate of Cu capture and removal from Aβ, while the kinetic aspect of the chelation was an issue encountered with the 4N parent ligand. The best ligand for removing Cu from Aβ and inhibiting the associated ROS production is the 1-thia-4,7,10-triazacyclododecane [3N1S]. Indeed the replacement of more N by S atoms makes the corresponding Cu complexes easier to reduce and thus able to produce ROS on their own. In addition, the ligand with three sulfur atoms has a weaker affinity for Cu^II than Aβ, and is thus unable to remove Cu from CuAβ.

Sequence-Activity Relationship of ATCUN Peptides in the Context of Alzheimer's Disease

Amino-terminal Cu^II and Ni^II (ATCUN) binding sequences are widespread in the biological world. Here, we report on the study of eight ATCUN peptides aimed at targeting copper ions and stopping the associated formation of reactive oxygen species (ROS). This study was actually more focused on Cu(Aβ)-induced ROS production in which the Aβ peptide is the "villain" linked to Alzheimer's disease. The full characterization of Cu^II binding to the ATCUN peptides, the Cu^II extraction from Cu^II(Aβ), and the ability of the peptides to prevent and/or stop ROS formation are described in the relevant biological conditions. We highlighted in this research that all the ATCUN motifs studied formed the same thermodynamic complex but that the addition of a second histidine in position 1 or 2 allowed for an improvement in the Cu^II uptake kinetics. This kinetic rate was directly related to the ability of the peptide to stop the Cu^II(Aβ)-induced production of ROS, with the most efficient motifs being HWHG and HGHW.

Umbelliferyloxymethyl phosphonate compounds-weakly binding zinc ionophores with neuroprotective properties

Umbelliferone is a member of the coumarin family of compounds which are known for diverse pharmacological activity including in targets relevant to Alzheimers disease, AD. The toxicity associated with some forms of the amyloid protein, Aβ, and the role of Zn2+ (and other biometals) dyshomeostasis in this, are of great interest in AD and make metal ionophore capability desirable in so called multi target drug ligands MTDLs. A new series of umbelliferyloxymethyl phosphonic acid diethylester compounds (umbelliferyloxymethyl phosphonates) bearing a phosphonate at the 7-position (compounds 1, 3-6), hydrolysis products 2, 2a and 2b from 1 and analogues 7 and 8 of 1 with 7-O to 7-S and 1-O to 1-NH substitutions, are reported. Single crystal X-ray structures of compounds 1, 2 and 2a were determined. In terms of neuroprotective properties, the compounds 1, 2, 3, 4, 5 and 6 at 1 μM concentration, inhibited the toxicity of Aβ1-42 (Aβ42) in both toxic Amyloid Derived Diffusible Ligand (ADDL) and fibrillar (fibril) forms towards rat hippocampal cells. Compound 7 displayed cytotoxicity and 8 failed to inhibit Aβ42 toxicity. Concerning compound-metal ionophore activity (assessed using chemical experiments), despite weak binding to Zn2+ determined from 31P NMR titration of 1 and 2 by ZnCl2, compounds 1, 3, 4, 5 and 6 demonstrated ionophore assisted partition of Zn2+ from water to octanol at micromolar concentrations with efficacy on a par with or better than the chelator MTDL clioquinol (5-chloro-7-iodo-8-hydroxyquinoline). Partition was assessed using furnace Atomic Absorption Spectroscopy (AAS). In further experiments interaction of compound 1 with Zn2+ or it's pathways was inferred by (i) delayed fluorescence response with added Zn2+ in cells treated with FluoZin-3 and (ii) by suppression of Zn2+ promoted aggregation of Aβ42.

Oxidative Modification of Proteins: From Damage to Catalysis, Signaling, and Beyond

Significance: The systematic investigation of oxidative modification of proteins by reactive oxygen species started in 1980. Later, it was shown that reactive nitrogen species could also modify proteins. Some protein oxidative modifications promote loss of protein function, cleavage or aggregation, and some result in proteo-toxicity and cellular homeostasis disruption. Recent Advances: Previously, protein oxidation was associated exclusively to damage. However, not all oxidative modifications are necessarily associated with damage, as with Met and Cys protein residue oxidation. In these cases, redox state changes can alter protein structure, catalytic function, and signaling processes in response to metabolic and/or environmental alterations. This review aims to integrate the present knowledge on redox modifications of proteins with their fate and role in redox signaling and human pathological conditions. Critical Issues: It is hypothesized that protein oxidation participates in the development and progression of many pathological conditions. However, no quantitative data have been correlated with specific oxidized proteins or the progression or severity of pathological conditions. Hence, the comprehension of the mechanisms underlying these modifications, their importance in human pathologies, and the fate of the modified proteins is of clinical relevance. Future Directions: We discuss new tools to cope with protein oxidation and suggest new approaches for integrating knowledge about protein oxidation and redox processes with human pathophysiological conditions. Antioxid. Redox Signal. 35, 1016-1080.

Copper Toxicity Links to Pathogenesis of Alzheimer's Disease and Therapeutics Approaches

Alzheimer's disease (AD) is an irreversible, age-related progressive neurological disorder, and the most common type of dementia in aged people. Neuropathological lesions of AD are neurofibrillary tangles (NFTs), and senile plaques comprise the accumulated amyloid-beta (Aβ), loaded with metal ions including Cu, Fe, or Zn. Some reports have identified metal dyshomeostasis as a neurotoxic factor of AD, among which Cu ions seem to be a central cationic metal in the formation of plaque and soluble oligomers, and have an essential role in the AD pathology. Cu-Aβ complex catalyzes the generation of reactive oxygen species (ROS) and results in oxidative damage. Several studies have indicated that oxidative stress plays a crucial role in the pathogenesis of AD. The connection of copper levels in AD is still ambiguous, as some researches indicate a Cu deficiency, while others show its higher content in AD, and therefore there is a need to increase and decrease its levels in animal models, respectively, to study which one is the cause. For more than twenty years, many in vitro studies have been devoted to identifying metals' roles in Aβ accumulation, oxidative damage, and neurotoxicity. Towards the end, a short review of the modern therapeutic approach in chelation therapy, with the main focus on Cu ions, is discussed. Despite the lack of strong proofs of clinical advantage so far, the conjecture that using a therapeutic metal chelator is an effective strategy for AD remains popular. However, some recent reports of genetic-regulating copper transporters in AD models have shed light on treating this refractory disease. This review aims to succinctly present a better understanding of Cu ions' current status in several AD features, and some conflicting reports are present herein.

Role of PTA in the prevention of Cu(amyloid-β) induced ROS formation and amyloid-β oligomerisation in the presence of Zn

Metal-targeting drugs are being widely explored as a possible treatment for Alzheimer's disease, but most of these ligands are developed to coordinate Cu(ii). In a previous communication (E. Atrián-Blasco, E. Cerrada, A. Conte-Daban, D. Testemale, P. Faller, M. Laguna and C. Hureau, Metallomics, 2015, 7, 1229-1232) we showed another strategy where Cu(i) was targeted with the PTA (1,3,5-triaza-7-phosphaadamantane) ligand that is able to target Cu(ii) as well, reduce it and keep it in a safe complexed species. Removal of Cu(ii) from the amyloid-β peptide prevents the stabilization of oligomers and protofibrils and the complexation of Cu(i) also stops the formation of reactive oxygen species. Besides, zinc, which is found in the synaptic cleft at a higher concentration than copper, can hamper the ability of metal-targeting drug candidates, an issue that is still poorly considered and studied. Here we show that PTA fully retains the above described properties even in the presence of zinc, thus fulfilling an additional pre-requisite for its use as a model of Cu(i)-targeting drug candidates in the Alzheimer's disease context.

Copper reduction and dioxygen activation in Cu-amyloid beta peptide complexes: insight from molecular modelling

Alzheimer's disease (AD) involves a number of factors including an anomalous interaction of copper with the amyloid peptide (Aβ), inducing oxidative stress with radical oxygen species (ROS) production through a three-step cycle in which O2 is gradually reduced to superoxide, oxygen peroxide and finally OH radicals. The purpose of this work has been to investigate the reactivity of 14 different Cu(ii)-Aβ coordination models with the aim of identifying on an energy basis (Density Functional Theory (DFT) and classical Molecular Dynamics (MD)) the redox competent form(s). Accordingly, we have specifically focused on the first three steps of the cycle, i.e. ascorbate binding to Cu(ii), Cu(ii) → Cu(i) reduction and O2 reduction to O2-. Compared to the recent literature, our results broaden the set of possible redox competent metallopeptide forms responsible for ROS production. Indeed, in addition to the three-coordinated species containing one His ligand, a N-terminal amine group and the carboxylate side chain of the Asp1 residue of Aβ already proposed, we found two other Cu-Aβ coordination modes involving two histidines.

Thermodynamic stability and structure in aqueous solution of the [Cu(PTA)4]+ complex (PTA = aminophosphine‑1,3,5‑triaza‑7‑phosphaadamantane)

The chemistry of copper(I) with water-soluble phosphines is an emergent area of study which has the objective of finding ligands that stabilize copper in its lower oxidation state. Cu(I) has been found relevant in the mechanism of copper transports into cells, and the accessibility of this oxidation state has implications in oxidative stress processes. For these reasons the possibility to deal with stable, water soluble copper(I) is an attractive approach for devising new biologically relevant metal-based drugs and chelating agents. Here we present the X-ray absorption spectroscopy (XAS) and UV-visible spectrophotometric study of the [Cu(PTA)₄]BF₄ complex (PTA = aminophosphine‑1,3,5‑triaza‑7‑phosphaadamantane). In particular, we have studied the stability of the [Cu(PTA)_n]⁺ species (n = 2-4) in aqueous medium, and their speciation as a function of the total [Cu(PTA)₄]BF₄ concentration by means of competitive UV-visible spectrophotometric titrations using metallochromic indicators. Also, the structure in solution of the Cu(I)/PTA species and the nature of the first coordination sphere of the metal were studied by transformed XAS. Both techniques allowed to study samples with total [Cu(PTA)₄]BF₄ concentration down to 68-74 μM, possibly relevant for biological applications. Overall, our data suggest that the [Cu(PTA)_n]⁺ species are stable in solution, among which [Cu(PTA)₂]⁺ has a remarkable thermodynamic stability. The tendency of this last complex to form adducts with N-donor ligands is demonstrated by the spectrophotometric data. The biological relevance of PTA towards Cu(I), especially in terms of chemotreatments and chelation therapy, is discussed on the basis of the speciation model the Cu(I)/PTA system.

Cross talk between neurometals and amyloidogenic proteins at the synapse and the pathogenesis of neurodegenerative diseases

Increasing evidence suggests that disruption of metal homeostasis contributes to the pathogenesis of various neurodegenerative diseases, including Alzheimer's disease, prion diseases, Lewy body diseases, and vascular dementia. Conformational changes of disease-related proteins (amyloidogenic proteins), such as β-amyloid protein, prion proteins, and α-synuclein, are well-established contributors to neurotoxicity and to the pathogenesis of these diseases. Recent studies have demonstrated that these amyloidogenic proteins are metalloproteins that bind trace elements, including zinc, iron, copper, and manganese, and play significant roles in the maintenance of metal homeostasis. We present a current review of the role of trace elements in the functions and toxicity of amyloidogenic proteins, and propose a hypothesis integrating metal homeostasis and the pathogenesis of neurodegenerative diseases that is focused on the interactions among metals and between metals and amyloidogenic proteins at the synapse, considering that these amyloidogenic proteins and metals are co-localized at the synapse.

Kinetics Are Crucial When Targeting Copper Ions to Fight Alzheimer's Disease: An Illustration with Azamacrocyclic Ligands

Targeting copper ions to either remove or redistribute them is currently viewed as a possible therapeutic strategy in the context of Alzheimer's disease (AD). Thermodynamic parameters, as for instance the copper(II) affinity of the drug candidate or the copper(II) over zinc(II) selectivity, are considered in the design of the drug candidate. In contrast, kinetic factors have been overlooked despite their probable high importance. In the present article, we use a series of azamacrocyclic ligands to demonstrate that kinetic issues must be taken into account when designing copper-targeting drug candidates in the context of AD.

N4 -Tetradentate Chelators Efficiently Regulate Copper Homeostasis and Prevent ROS Production Induced by Copper-Amyloid-β1-16

The disruption of copper homeostasis and the oxidative stress induced by Cu-amyloids are crucial features of Alzheimer's disease pathology. The copper specific N₄ -tetradendate ligands TDMQ20 and 1 are able to fully inhibit in vitro the aerobic oxidation of ascorbate induced by Cu-Aβ_1-16 , even in the presence of 100 molar equivalents of Zn^II with respect to Cu^II , whereas other ligands with N₂ O₂ or N₃ O₂ coordination spheres failed to do so. This essential result indicates that, in addition to metal selectivity, the coordination sphere of copper chelators should exhibit a N₄ -tetradendate motif to be able to reduce an oxidative stress in the zinc-rich physiological environment of brain. The N₄ -scaffolds of these two aminoquinoline-based ligands, TDMQ20 or 1, suitable for a square-planar coordination of copper(II), allowed them to enhance both the selectivity for copper and the ability to reduce the oxidative stress induced by copper-amyloid in a zinc-rich environment.

Ascorbate Oxidation by Cu(Amyloid-β) Complexes: Determination of the Intrinsic Rate as a Function of Alterations in the Peptide Sequence Revealing Key Residues for Reactive Oxygen Species Production

Along with aggregation of the amyloid-β (Aβ) peptide and subsequent deposit of amyloid plaques, oxidative stress is an important feature in Alzheimer's disease. Cu bound to Aβ is able to produce reactive oxygen species (ROS) by the successive reductions of molecular dioxygen, and the ROS produced contribute to oxidative stress. In vitro, ascorbate consumption parallels ROS production, where ascorbate is the reductant that fuels the reactions. Because the affinity of Cu for Aβ is moderate compared to other biomolecules, the rate of ascorbate consumption is a combination of two contributions. The first one is due to peptide-unbound Cu and the second one to peptide-bound Cu complexes. In the present Article, we aim to determine the amounts of the second contribution in the global ascorbate consumption process. It is defined as the intrinsic rate of ascorbate oxidation, which mathematically corresponds to the rate at an infinite peptide to Cu ratio, i.e., without any contribution from peptide-unbound Cu. We show that, for the wild-type Cu(Aβ) complex, this value equals 10% of the value obtained for peptide-unbound Cu and that this value is strongly dependent on peptide alterations. By examination of the dependence of the intrinsic rate of ascorbate oxidation, followed by UV-vis spectroscopy, for several altered peptides, we determine some of the key residues that influence ROS production.

Is ascorbate Dr Jekyll or Mr Hyde in the Cu(Aβ) mediated oxidative stress linked to Alzheimer's disease?

Evaluation of the pro versus antioxidant activity of ascorbate regarding Cu(Aβ) induced reactive oxygen species production in the context of Alzheimer’s disease shows that a protective activity can only be observed at high ascorbate concentration for exogenous molecules but not for the amyloid-β peptide itself.

Role of Copper in the Onset of Alzheimer's Disease Compared to Other Metals

Alzheimer's disease (AD) is a neurodegenerative disorder that is characterized by amyloid plaques in patients' brain tissue. The plaques are mainly made of β-amyloid peptides and trace elements including Zn2+, Cu2+, and Fe2+. Some studies have shown that AD can be considered a type of metal dyshomeostasis. Among metal ions involved in plaques, numerous studies have focused on copper ions, which seem to be one of the main cationic elements in plaque formation. The involvement of copper in AD is controversial, as some studies show a copper deficiency in AD, and consequently a need to enhance copper levels, while other data point to copper overload and therefore a need to reduce copper levels. In this paper, the role of copper ions in AD and some contradictory reports are reviewed and discussed.

Chemistry of mammalian metallothioneins and their interaction with amyloidogenic peptides and proteins

Cu and Zn ions are essential in most living beings. Their metabolism is critical for health and mis-metabolism can be lethal. In the last two decades, a large body of evidence has reported the role of copper, zinc and iron, and oxidative stress in several neurodegenerative diseases like Alzheimer's, Parkinson's, prion diseases, etc. To what extent this mis-metabolism is causative or a consequence of these diseases is still a matter of research. In this context metallothioneins (MTs) appear to play a central gate-keeper role in controlling aberrant metal-protein interactions. MTs are small proteins that can bind high amounts of Zn(ii) and Cu(i) ions in metal-cluster arrangements via their cysteine thiolates. Moreover, MTs are well known antioxidants. The present tutorial outlines the chemistry underlying the interconnection between copper(i/ii) and zinc(ii) coordination to amyloidogenic proteins and MTs, and their redox properties in generation and/or silencing reactive oxygen species (overproduced in oxidative stress) and other reactants. These studies have revealed the coordination chemistry involved in neurodegenerative diseases and the interactions between MTs and amyloidogenic protein metal-complexes (like amyloid-β, α-synuclein and prion-protein). Overall, the protective role of MTs in neurodegenerative processes is emerging, serving as a foundation for exploring MT chemistry as inspiration for therapeutic approaches.

A Trishistidine Pseudopeptide with Ability to Remove Both CuΙ and CuΙΙ from the Amyloid-β Peptide and to Stop the Associated ROS Formation

The pseudopeptide L, derived from a nitrilotriacetic acid scaffold and functionalized with three histidine moieties, is reminiscent of the amino acid side chains encountered in the Alzheimer's peptide (Aβ). Its synthesis and coordination properties for CuΙ and CuΙΙ are described. L efficiently complex CuΙΙ in a square-planar geometry involving three imidazole nitrogen atoms and an amidate-Cu bond. By contrast, CuΙ is coordinated in a tetrahedral environment. The redox behavior is irreversible and follows an ECEC mechanism in accordance with the very different environments of the two redox states of the Cu center. This is in line with the observed resistance of the CuΙ complex to oxidation by oxygen and the CuΙΙ complex reduction by ascorbate. The affinities of L for CuΙΙ and CuΙ at physiological pH are larger than that reported for the Aβ peptide. Therefore, due to its peculiar Cu coordination properties, the ligand L is able to target both redox states of Cu, redox silence them and prevent reactive oxygen species production by the CuAβ complex. Because reactive oxygen species contribute to the oxidative stress, a key issue in Alzheimer's disease, this ligand thus represents a new strategy in the long route of finding molecular concepts for fighting Alzheimer's disease.

Mutual interference of Cu and Zn ions in Alzheimer's disease: perspectives at the molecular level

While metal ions such as copper and zinc are essential in biology, they are also linked to several amyloid-related diseases, including Alzheimer's disease (AD).

While metal ions such as copper and zinc are essential in biology, they are also linked to several amyloid-related diseases, including Alzheimer's disease (AD). Zinc and copper can indeed modify the aggregation pathways of the amyloid-β (Aβ) peptide, the key component encountered in AD. In addition, the redox active copper ions do produce Reactive Oxygen Species (ROS) when bound to the Aβ peptide. While Cu(i) or Cu(ii) or Zn(ii) coordination to the Aβ has been extensively studied in the last ten years, characterization of hetero-bimetallic Aβ complexes is still scarce. This is also true for the metal induced Aβ aggregation and ROS production, for which studies on the mutual influence of the copper and zinc ions are currently appearing. Last but not least, zinc can strongly interfere in therapeutic approaches relying on copper detoxification. This will be exemplified with a biological lead, namely metallothioneins, and with synthetic ligands.

Identification of key structural features of the elusive Cu-Aβ complex that generates ROS in Alzheimer's disease

Oxidative stress is linked to the etiology of Alzheimer's disease (AD), the most common cause of dementia in the elderly. Redox active metal ions such as copper catalyze the production of Reactive Oxygen Species (ROS) when bound to the amyloid-β (Aβ) peptide encountered in AD. We propose that this reaction proceeds through a low-populated Cu-Aβ state, denoted the "catalytic in-between state" (CIBS), which is in equilibrium with the resting state (RS) of both Cu(i)-Aβ and Cu(ii)-Aβ. The nature of this CIBS is investigated in the present work. We report the use of complementary spectroscopic methods (X-ray absorption spectroscopy, EPR and NMR) to characterize the binding of Cu to a wide series of modified peptides in the RS. ROS production by the resulting Cu-peptide complexes was evaluated using fluorescence and UV-vis based methods and led to the identification of the amino acid residues involved in the Cu-Aβ CIBS species. In addition, a possible mechanism by which the ROS are produced is also proposed. These two main results are expected to affect the current vision of the ROS production mechanism by Cu-Aβ but also in other diseases involving amyloidogenic peptides with weakly structured copper binding sites.

Fluorescent Copper Probe Inhibiting Aβ1-16-Copper(II)-Catalyzed Intracellular Reactive Oxygen Species Production

A variety of fluorescent probes are proposed to monitor the intracellular copper content. So far, none of the probes have been evaluated for their potential to inhibit copper-associated intracellular oxidative stress. Herein, we studied the ability of a fluorescent copper probe, OBEP-CS1, to inhibit intracellular oxidative stress associated with an amyloid β (Aβ) peptide-copper complex. The data showed that OBEP-CS1 completely inhibits the copper-catalyzed oxidation as well as decarboxylation/deamination of Aβ1-16. Moreover, the cell imaging experiments confirmed that OBEP-CS1 can inhibit Aβ-Cu^II-catalyzed reactive oxygen species production in SH-SY5Y cells. We also demonstrated that Aβ1-16 peptide can bind intracellular copper and thereby exert oxidative stress.

How Zn can impede Cu detoxification by chelating agents in Alzheimer's disease: a proof-of-concept study

The role of Cu and Zn ions in Alzheimer's disease is linked to the consequences of their coordination to the amyloid-β (Aβ) peptide, i.e. to the modulation of Aβ aggregation and to the production of Reactive Oxygen Species (ROS), two central events of the so-called amyloid cascade. The role of both ions in Aβ aggregation is still controversial. Conversely the higher toxicity of the redox competent Cu ions (compared to the redox inert Zn ions) in ROS production is acknowledged. Thus the Cu ions can be considered as the main therapeutic target. Because Zn ions are present in higher quantity than Cu ions in the synaptic cleft, they can prevent detoxification of Cu by chelators unless they have an unusually high Cu over Zn selectivity. We describe a proof-of-concept study where the role of Zn on the metal swap reaction between two prototypical ligands and the Cu(Aβ) species has been investigated by several complementary spectroscopic techniques (UV-Vis, EPR and XANES). The first ligand has a higher Cu over Zn selectivity relative to the one of Aβ peptide while the second one exhibits a classical Cu over Zn selectivity. How Zn impacts the effect of the ligands on Cu-induced ROS production and Aβ aggregation is also reported.

Homoleptic phosphino copper(I) complexes with in vitro and in vivo dual cytotoxic and anti-angiogenic activity

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.