Synergistic effects between a copper-based metal Casiopeína III-ia and cisplatin

Encapsulation of copper phenanthroline within horse spleen apoferritin: characterisation, cytotoxic activity and ability to retain temozolomide

Protein capsules are promising drug delivery vehicles for cancer research therapies. Apoferritin (AFt) is a self-assembling 12 nm diameter hollow nanocage with many desirable features for drug delivery, however, control of drug retention inside the protein cage remains challenging. Here we report the encapsulation of copper(ii)-1,10-phenanthroline (Cu(phen)) within the horse spleen AFt (HSAFt) nanocage, by diffusion of the metal through the pores between the protein subunits. Transmission electron microscopy revealed the formation of organised copper adducts inside HSAFt, without affecting protein integrity. These structures proved stable during storage (>4 months at -20 °C). Exposure to physiologically relevant conditions (37 °C) showed some selectivity in cargo release after 24 h at pH 5.5, relevant to the internalisation of AFt within the endosome (60% release), compared to pH 7.4, relevant to the bloodstream (40% release). Co-encapsulation of temozolomide, a prodrug used to treat glioblastoma multiforme, and Cu(phen) enabled entrapment of an average of 339 TMZ molecules per cage. In vitro results from MTT and clonogenic assays identified cytotoxic activity of the Cu(phen), HSAFt-Cu(phen) and HSAFt-Cu(phen)-TMZ adducts against colorectal cancer cells (HCT-116) and glioblastoma cells (U373V, U373M). However, the presence of the metal also contributed to more potent activity toward healthy MRC5 fibroblasts, a result that requires further investigation to assess the clinical viability of this system.

Recently Reported Biological Activities and Action Targets of Pt(II)- and Cu(II)-Based Complexes

Most diseases that affect human beings across the world are now treated with drugs of organic origin. However, some of these are associated with side effects, toxicity, and resistance phenomena. For the treatment of many illnesses, the development of new molecules with pharmacological potential is now an urgent matter. The biological activities of metal complexes have been reported to have antitumor, antimicrobial, anti-inflammatory, anti-infective and antiparasitic effects, amongst others. Metal complexes are effective because they possess unique properties. For example, the complex entity possesses the effective biological activity, then the formation of coordination bonds between the metal ions and ligands is controlled, metal ions provide it with extraordinary mechanisms of action because of characteristics such as d-orbitals, oxidation states, and specific orientations; metal complexes also exhibit good stability and good physicochemical properties such as water solubility. Platinum is a transition metal widely used in the design of drugs with antineoplastic activities; however, platinum is associated with side effects which have made it necessary to search for, and design, novel complexes based on other metals. Copper is a biometal which is found in living systems; it is now used in the design of metal complexes with biological activities that have demonstrated antitumoral, antimicrobial and anti-inflammatory effects, amongst others. In this review, we consider the open horizons of Cu(II)- and Pt(II)-based complexes, new trends in their design, their synthesis, their biological activities and their targets of action.

Structural and solution speciation studies on selected [Cu(NN)(OO)] complexes and an investigation of their biomimetic activity, ROS generation and their cytotoxicity in normoxic, hypoxic and anoxic environments in MCF-7 breast cancer-derived cells

Reactive oxygen species(ROS) generation with subsequent DNA damage is one of the principle mechanisms of action assigned to copper-based anticancer complexes. The efficacy of this type of chemotherapeutic may be reduced in the low oxygen environment of tumours. In this study the cytotoxicity of three complexes, [Cu(dips)(phen)] (1), [Cu(ph)(phen)]·2H2O (2) and [Cu(ph)(bpy)]·H2O (3) (disp: 3,5-diisopropylsalicylate, phen: 1,10- phenanthroline, ph: phthalate, bpy: 2,2'-bipyridyl) were assessed for anticancer activity in the breast-cancer derived MCF-7 line under normoxic, hypoxic and anoxic conditions. In an immortalised keratinocyte HaCaT cell line, the cytotoxicity of complexes 2 and 3 was significantly reduced under both normoxic and hypoxic conditions, whilst the cytotoxicity of complex 1 was increased under hypoxic conditions. The ability of the complexes to generate ROS in the MCF-7 cell line was evaluated as was their ability to act as superoxide dismutase(SOD) and catalase mimics using a yeast cell assay. ROS generation was significant for complexes 2 and 3, less so for complex 1 though all three complexes had SOD mimetic ability. Given the ternary nature of the complexes, solution speciation studies were undertaken but were only successful for complex 3, due to solubility issues with the other two complexes. The concentration distribution of various species, formed in aqueous solution, was evaluated as a function of pH and confirmed that complex 3 is the dominant species at physiological pH in the mM concentration range. However, as its concentration diminishes, it experiences a progressive dissociation, leading to the formation of binary complexes of bpy alongside unbound phthalate.

Targeting copper metabolism: a promising strategy for cancer treatment

Copper is an essential micronutrient that plays a critical role in many physiological processes. However, excessive copper accumulation in cancer cells has been linked to tumor growth and metastasis. This review article explores the potential of targeting copper metabolism as a promising strategy for cancer treatment. Excessive copper accumulation in cancer cells has been associated with tumor growth and metastasis. By disrupting copper homeostasis in cancer cells and inducing cell death through copper-dependent mechanisms (cuproplasia and cuprotosis, respectively), therapies can be developed with improved efficacy and reduced side effects. The article discusses the role of copper in biological processes, such as angiogenesis, immune response, and redox homeostasis. Various approaches for targeting copper metabolism in cancer treatment are examined, including the use of copper-dependent enzymes, copper-based compounds, and cuprotosis-related genes or proteins. The review also explores strategies like copper chelation therapy and nanotechnology for targeted delivery of copper-targeting agents. By understanding the intricate network of cuprotosis and its interactions with the tumor microenvironment and immune system, new targets for therapy can be identified, leading to improved cancer treatment outcomes. Overall, this comprehensive review highlights the significant potential of targeting copper metabolism as a promising and effective approach in cancer treatment, while providing valuable insights into the current state of research in this field.

Electrochemical and CD-spectroelectrochemical studies of the interaction between BSA and the complex [Cu(Bztpen)]2+, (Bztpen = (N-benzyl-N, N', N'-tris (pyridin-2-ylmethyl) ethylenediamine)

In this work we report the electrochemical, spectroscopical and spectro-electrochemical studies of a model complex [Cu^ΙΙ(Bztpen)]²⁺, (Bztpen = (N-benzyl-N,N',N'-tris(pyridin-2-ylmethyl)ethylenediamine) in order to propose a methodology to evaluate the interaction of potential metal based anticancer agents during electron transfer processes, with transport proteins such as Bovine Serum Albumin (BSA). It was possible to establish a reversible electron transfer [Cu^ΙΙ(Bztpen)]²⁺ +1e → [Cu^Ι(Bztpen)]⁺ and a weak interaction energy between BSA and [Cu^ΙΙ(Bztpen)] and [Cu^Ι(Bztpen)] species, with no adsorption of protein over the electrode surface. Circular Dichroism (CD) Spectroelectrochemistry, not reported before, reveals no significant changes in BSA structure during the electron transfer [Cu^ΙΙ(Bztpen)]²⁺ + 1e → [Cu^Ι(Bztpen)]⁺. CD experiments at variable temperature for BSA denaturalization in the absence and in the presence of [Cu^ΙΙ(Bztpen)]²⁺, shown no change in thermodynamic parameters due to low interaction between the transport protein and copper complex.

Casiopeinas of Third Generations: Synthesis, Characterization, Cytotoxic Activity and Structure-Activity Relationships of Mixed Chelate Compounds with Bioactive Secondary Ligands

Casiopeinas are a family of copper(II) coordination compounds that have shown an important antineoplastic effect and low toxicity in normal cells. These compounds induce death cells by apoptosis through a catalytic redox process with endogenous reducing agents. Further studies included a structural variation, improving the activity and selectivity in cancer cells or other targets. In the present work we report the third generation, which contains a bioactive monocharged secondary ligand, as well as the design, synthesis, characterization and antiproliferative activity, of sixteen new copper(II) coordination compounds with curcumin or dimethoxycurcumin as secondary ligands. All compounds were characterized by elemental analysis, FTIR, UV-Vis, magnetic susceptibility, mass spectra with MALDI-flight time, cyclic voltammetry, electron paramagnetic resonance (EPR) spectroscopy and X-ray diffraction. Crystallization of two complexes was achieved in dimethylsulfoxide (DMSO) with polar solvent, and crystal data demonstrated that a square-based or square-base pyramid geometry are possible. A 1:1:1 stoichiometry (diimine: copper: curcuminoid) ratio and the possibility of a nitrate ion as a counterion were supported. ¹H, ¹³C NMR spectra were used for the ligands. A sulforhodamine B assay was used to evaluate the cytotoxicity effect against two human cancer cell lines, SKLU-1 and HeLa. Electronic descriptors and redox potential were obtained by DFT calculations. Structure–activity relationships are strongly determined by the redox potential (E_1/2) of copper(II) and molar volume (V) of the complexes. These compounds can be used as a template to open a wide field of research both experimentally and theoretically.

Antitumoral synergism between a copper(II) complex and cisplatin improves in vitro and in vivo anticancer activity against melanoma, lung and breast cancer cells

BACKGROUND

Intrinsic resistance of cancer cells is a major concern for the success of chemotherapy, and this undesirable feature stimulates further research into the design of new compounds and/or alternative multiple drug chemotherapy protocols.

METHODS

In this study, we investigated the antitumoral potential of the coordination compounds [Cu(HPClNOL)Cl]Cl (1), [Fe(HPClNOL)Cl₂]NO₃(2) and [Mn(HPClNOL)Cl₂] (3). Using the human, MCF-7 and A549, and the murine melanoma, B16-F10, cell lines, we determined the cytotoxicity, DCFH oxidation, disruption of mitochondrial membrane potential (ΔΨm), Sub-G1 and TUNEL positive cells, and caspase 8 and 9 activities. Fractional inhibitory concentration (FIC) and xenograft models were also assessed to evaluate the efficacy of antitumoral potential.

RESULTS

We observed that only complex 1 was cytotoxic. The treatment of cancer cells with complex 1 triggered ROS generation and promoted the disruption of ΔΨm. Complex 1 increased the number of Sub-G1 and TUNEL positive cells, and the measurement of caspase 8 and 9 activity confirmed that apoptosis was triggered by the intrinsic pathway. FIC demonstrated that the combination of complex 1 with cisplatin was additive for the A549 cells whilst it was synergic for MCF-7 and B16-F10. Treatment with complex 1, either alone or combined with cisplatin, reduced tumor growth on xenograft models.

CONCLUSIONS

The present study brings new clues regarding the mechanism of action of [Cu(HPClNOL)Cl]Cl, either alone or in combination with cisplatin.

GENERAL SIGNIFICANCE

These results indicate that complex 1, administered either singly or in combination with current drugs, has real potential for use in cancer therapy.

Non-Steroidal Anti-Inflammatory Drugs Increase Cisplatin, Paclitaxel, and Doxorubicin Efficacy against Human Cervix Cancer Cells

This study shows that the non-steroidal anti-inflammatory drug (NSAID) celecoxib and its non-cyclooxygenase-2 (COX2) analogue dimethylcelecoxib (DMC) exert a potent inhibitory effect on the growth of human cervix HeLa multi-cellular tumor spheroids (MCTS) when added either at the beginning (“preventive protocol”; IC₅₀ = 1 ± 0.3 nM for celecoxib and 10 ± 2 nM for DMC) or after spheroid formation (“curative protocol”; IC₅₀ = 7.5 ± 2 µM for celecoxib and 32 ± 10 µM for DMC). These NSAID IC₅₀ values were significantly lower than those attained in bidimensional HeLa cells (IC₅₀ = 55 ± 9 µM celecoxib and 48 ± 2 µM DMC) and bidimensional non-cancer cell cultures (3T3 fibroblasts and MCF-10A mammary gland cells with IC₅₀ from 69 to >100 µM, after 24 h). The copper-based drug casiopeina II-gly showed similar potency against HeLa MCTS. Synergism analysis showed that celecoxib, DMC, and casiopeinaII-gly at sub-IC₅₀ doses increased the potency of cisplatin, paclitaxel, and doxorubicin to hinder HeLa cell proliferation through a significant abolishment of oxidative phosphorylation in bidimensional cultures, with no apparent effect on non-cancer cells (therapeutic index >3.6). Similar results were attained with bidimensional human cervix cancer SiHa and human glioblastoma U373 cell cultures. In HeLa MCTS, celecoxib, DMC and casiopeina II-gly increased cisplatin toxicity by 41–85%. These observations indicated that celecoxib and DMC used as adjuvant therapy in combination with canonical anti-cancer drugs may provide more effective alternatives for cancer treatment.

New Cu(II)-bearing coordination polymer: Crystal structure, molecular docking, and protective activity on coronary heart disease by reducing ROS production

A novel chain-like coordination polymer [CuLCl2(DMF)]n (1) with helical double chains was synthesized using flexible bis(pyridylurea) ligand 1,1[Formula: see text]-[oxybis(2,1-phenylene)] bis(3-pyridin-3-ylurea) (L) under solvothermal conditions and characterized by single-crystal X-ray diffraction and elemental analysis. A green grinding processing method was used to produce the required complex 1 nanorods, which featured good water dispersibility. The protective effect of the compound was evaluated in vivo, following the construction of the coronary heart disease (CHD) rat model and nano 1 treatment. The cardiac function promoted by nano 1 was measured using the left ventricular systolic diameter (LVID) and left ventricular ejection fraction (LVEF). The anti-oxidative activity of nano 1 was determined with an ROS detection kit. In addition, the interaction between the Cu(II) complex with protein NF-[Formula: see text]B was examined by molecular docking.

Esterification of the free carboxylic group from the lutidinic acid ligand as a tool to improve the cytotoxicity of Ru(ii) complexes

The esterification of the free carboxyl group in ruthenium complexes improves the complex interactions with biomolecules, lipophilicity, and cellular uptake, making them more selective against tumor cells than cisplatin.

Interactions of Schiff base compounds and their coordination complexes with the drug cisplatin

There is a complex interplay between the structural and other physicochemical properties of new compounds and the molecules in living organisms.