New copper(I) complexes bearing lomefloxacin motif: Spectroscopic properties, in vitro cytotoxicity and interactions with DNA and human serum albumin

Unraveling environmental effects in the absorption and fluorescence spectra of p-methoxyphenylpiperazine derivatives

The p-methoxyphenylpiperazine motif can be found in many biologically active molecules, including approved drugs. It is characterized by a relatively weak fluorescence, which can be employed in different types of studies involving molecules with this motif. In this work, a thorough analysis of the absorption, excitation and emission spectra of the diphenyl(aminomethyl)phosphine and tris(aminomethyl)phosphine derivatives of p-methoxyphenylpiperazine, supported by the DFT calculations (ωB97XD/6-311++G(d,p)) with NBO and QTAIM analysis also for different model molecules (e.g. 1-(4-methoxyphenyl)-4-methylpiperazine) enabled determination of the mechanisms underlying beneath the electronic transitions and allowed to rationalize mixed solvent effects observed in electronic spectra of the studied compounds. Electronic transition from the ground state to the first excited state can be regarded as the n,π → π* transition with no solvatochromic effects, however the hydrogen bonds between the HBD solvent molecules and the nitrogen atom bound directly to the aromatic ring (N(4)) are shifting strongly the 1st absorption or excitation band maxima to the higher energies. Fluorescence band, as a result of the electron transition from the equilibrated 1st excited state to the ground state, can be described as the π*→π with positive solvatochromism. N(4) in the excited states adopts a sp2 hybridization and is no longer able to form HBs. On the other hand, increased electron density on the aromatic ring makes the emission processes vulnerable to its direct environment.

Anticandidal Cu(I) complexes with neocuproine and 1-(4-methoxyphenyl)piperazine based diphenylaminomethylphosphine: Is Cu-diimine moiety a pharmacophore?

The studies on metal complexes as potential antifungals are of growing interest because they may be the answer to increasingly effective defense mechanisms. Herein we present two new copper(I) iodide or thiocyanide complexes with 2,9-dimethyl-1,10-phenanthroline (dmp) and diphenylphosphine derivative of 1-(4-methoxyphenyl)piperazine (4MP): [CuI(dmp)4MP] (1-4MP) and [CuNCS(dmp)4MP] (2-4MP) - their synthesis, as well as structural and spectroscopic characteristics. Interestingly, while 4MP and its oxide derivative (4MOP) show a very low or no activity against all tested Candida albicans strains (MIC50 ≥ 200 μM against CAF2-1 - laboratory control strain, DSY1050 - mutant without transporters Cdr1, Cdr2, Mdr1; isogenic for CAF2-1, and fluconazole resistant clinical isolates), for 1-4MP and 2-4MP MIC50 values were 0.4 μM, independently on the complex and strain tested. Determination of the viability of NHDF-Ad (Normal Adult Human Dermal Fibroblasts) cell line treated with 1-4MP and 2-4MP showed that for both complexes there was only a 20% reduction in the concentration range ¼ to 2 × MIC50 and the 70% at 4 × MIC50. Subsequently, the MLCT based luminescence of the complexes in aqueous media allowed to record the confocal micrographs of 1-4MP in the cells. The results show that it is situated most likely in the vacuoles (C. albicans) or lysosomes (NHDF-Ad).

DDTC-Cu(I) based metal-organic framework (MOF) for targeted melanoma therapy by inducing SLC7A11/GPX4-mediated ferroptosis

Disulfiram (DSF), a drug for alcohol withdrawal, has attracted extensive scientific attention due to its potential to treat cancer. The metabolite of DSF, diethyl dithiocarbamate (DDTC), forms a Cu-DDTC complex in vivo with copper ions, which has been shown to be a proteasome inhibitor with high antitumor activity. However, the in vivo stability of Cu-DDTC complexes remains a challenge. In this study, the nanomedicine Cu-BTC@DDTC with high antitumor activity was prepared by using the nanoscale metal-organic framework (MOF) Cu-BTC as a carrier and loading diethyldithiocarbamate (DDTC) through coordination interaction. The results showed that Cu-BTC@DDTC had high drug loading and adequate stability, and exhibited DDTC-Cu(I) chemical valence characteristics and polycrystalline structure features. In vitro cytocompatibility investigation and animal xenograft tumor model evaluation demonstrated the anti-cancer potential of Cu-BTC@DDTC, especially the combination of Cu-BTC@DDTC with low-dose cisplatin showed significant antitumor effect and biosafety. This study provides a feasible protocol for developing antitumor drugs based on the drug repurposing strategy.

Two out of Three Musketeers Fight against Cancer: Synthesis, Physicochemical, and Biological Properties of Phosphino CuI, RuII, IrIII Complexes

Two novel phosphine ligands, Ph2PCH2N(CH2CH3)3 (1) and Ph2PCH2N(CH2CH2CH2CH3)2 (2), and six new metal (Cu(I), Ir(III) and Ru(II)) complexes with those ligands: iridium(III) complexes: Ir(η5-Cp*)Cl2(1) (1a), Ir(η5-Cp*)Cl2(2) (2a) (Cp*: Pentamethylcyclopentadienyl); ruthenium(II) complexes: Ru(η6-p-cymene)Cl2(1) (1b), Ru(η6-p-cymene)Cl2(2) (2b) and copper(I) complexes: [Cu(CH3CN)2(1)BF4] (1c), [Cu(CH3CN)2(2)BF4] (2c) were synthesized and characterized using elemental analysis, NMR spectroscopy, and ESI-MS spectrometry. Copper(I) complexes turned out to be highly unstable in the presence of atmospheric oxygen in contrast to ruthenium(II) and iridium(III) complexes. The studied Ru(II) and Ir(III) complexes exhibited promising cytotoxicity towards cancer cells in vitro with IC50 values significantly lower than that of the reference drug—cisplatin. Confocal microscopy analysis showed that Ru(II) and Ir(III) complexes effectively accumulate inside A549 cells with localization in cytoplasm and nuclei. A precise cytometric analysis provided clear evidence for the predominance of apoptosis in induced cell death. Furthermore, the complexes presumably induce the changes in the cell cycle leading to G2/M phase arrest in a dose-dependent manner. Gel electrophoresis experiments revealed that Ru(II) and Ir(III) inorganic compounds showed their unusual low genotoxicity towards plasmid DNA. Additionally, metal complexes were able to generate reactive oxygen species as a result of redox processes, proved by gel electrophoresis and cyclic voltamperometry. In vitro cytotoxicity assays were also carried out within multicellular tumor spheroids and efficient anticancer action on these 3D assemblies was demonstrated. It was proven that the hydrocarbon chain elongation of the phosphine ligand coordinated to the metal ions does not influence the cytotoxic effect of resulting complexes in contrast to metal ions type.

Isothiocyanate l-argininato copper(II) complexes - Solution structure, DNA interaction, anticancer and antimicrobial activity

l-argininato copper(II) complexes have been intensively investigated in a variety of diseases due to their therapeutic potential. Here we report the results of comprehensive structural studies (ESI-MS, NIR-VIS-UV, EPR) on the complexes arising in aqueous solutions of two ternary copper(II) complexes with molecular formulas from crystal structures, [Cu(l-Arg)2(NCS)](NCS)·H2O (1) and [Cu(l-Arg)(NCS)2] (2) (l-Arg = l-arginine). Reference systems, the ternary Cu(II)/l-Arg/NCS- as well as binary Cu(II)/NCS- and Cu(II)/l-Arg, were studied in parallel in aqueous solutions by pH-potentiometric titration, EPR and VIS spectroscopy to characterize stability, structures and speciation of the formed species over the broad pH range. Comparative analysis of the obtained results showed that at a pH close to 7.0 mononuclear [Cu(l-Arg)2(NCS)]+ is the only species in water solution of 1, while equilibrium between [Cu(l-Arg)(SCN)]+ and binary [Cu(l-Arg)2]2+ was detected in water solution of 2. According to DNA binding studies, the [Cu(l-Arg)2(NCS)]+, [Cu(l-Arg)(SCN)]+ and [Cu(l-Arg)2]2+ species could be considered as strong minor groove binding agents causing, in the presence of H2O2, the involvement of ROS in plasmid damage. The human carcinoma cells (A549 cell line) were generally significantly more sensitive to cytotoxic and antiproliferative effect of compounds 1 and 2 than human normal cells. The studied compounds shown antimicrobial activity against bacteria belonging to Enterobacteriaceae family.

Identification of potent anticancer copper(ii) complexes containing tripodal bis[2-ethyl-di(3,5-dialkyl-1H-pyrazol-1-yl)]amine moiety

A series of heteroleptic copper(ii) complexes of the composition [Cu(L^1-5)Cl]X, where X = ClO₄ and/or PF₆ and [bis(2-ethyl-di(3,5-dimethyl-1H-pyrazol-1-yl))-(6-methyl-(2-pyridylmethyl))]amine (L¹), [bis(2-ethyl-di(3,5-dimethyl-1H-pyrazol-1-yl))-(3,4-dimethoxy-(2-pyridylmethyl))]amine (L²), [bis(2-ethyl-di(3,5-dimethyl-1H-pyrazol-1-yl)-(2-quinolymethyl)]amine (L³), [bis(2-ethyl-di(3,5-dimethyl-1H-pyrazolyl)-(di(3,5-dimethyl-1H-pyrazol-1-yl-methyl))]amine (L⁴) and [bis(2-ethyl-di(3,5-dimethyl-1H-pyrazol-1-yl)-(5-methyl-3-phenyl-1H-pyrazol-1-yl-methyl)]amine (L⁵), were prepared and thoroughly characterized including single-crystal X-ray diffraction technique. The in vitro cytotoxicity of complexes against A2780, A2780R, HOS and MCF-7 human cancer cell lines was evaluated using the MTT test. The results revealed that complexes [Cu(L¹)Cl]PF₆ (1-PF₆), [Cu(L²)Cl]ClO₄ (2-ClO₄) and [Cu(L³)Cl]PF₆ (3-PF₆) are the most effective, with IC₅₀ values ranging from 1.4 to 6.3 μM, thus exceeding the cytotoxic potential of metallodrug cisplatin (IC₅₀ values ranging from 29.9 to 82.0 μM). The complexes [Cu(L⁴)Cl]PF₆ (4-PF₆) and [Cu(L⁵)Cl]PF₆ (5-PF₆) showed only moderate cytotoxicity against A2780, with IC₅₀ = 53.6 μM, and 33.8 μM, respectively. The cell cycle profile, time-resolved cellular uptake, interactions with small sulfur-containing biomolecules (cysteine and glutathione), intracellular ROS production, induction of apoptosis and activation of caspases 3/7 were also evaluated in the case of the selected complexes. It has been found that the best performing complexes 1 and 2 cause cell arrest in the G2/M phase and induce apoptosis via the increase in production of ROS, dominantly due to the overproduction of superoxide.

Interaction between DNA, Albumin and Apo-Transferrin and Iridium(III) Complexes with Phosphines Derived from Fluoroquinolones as a Potent Anticancer Drug

A group of cytotoxic half-sandwich iridium(III) complexes with aminomethyl(diphenyl)phosphine derived from fluoroquinolone antibiotics exhibit the ability to (i) accumulate in the nucleus, (ii) induce apoptosis, (iii) activate caspase-3/7 activity, (iv) induce the changes in cell cycle leading to G2/M phase arrest, and (v) radicals generation. Herein, to elucidate the cytotoxic effects, we investigated the interaction of these complexes with DNA and serum proteins by gel electrophoresis, fluorescence spectroscopy, circular dichroism, and molecular docking studies. DNA binding experiments established that the complexes interact with DNA by moderate intercalation and predominance of minor groove binding without the capability to cause a double-strand cleavage. The molecular docking study confirmed two binding modes: minor groove binding and threading intercalation with the fluoroquinolone part of the molecule involved in pi stacking interactions and the Ir(III)-containing region positioned within the major or minor groove. Fluorescence spectroscopic data (HSA and apo-Tf titration), together with molecular docking, provided evidence that Ir(III) complexes can bind to the proteins in order to be transferred. All the compounds considered herein were found to bind to the tryptophan residues of HSA within site I (subdomain II A). Furthermore, Ir(III) complexes were found to dock within the apo-Tf binding site, including nearby tyrosine residues.

Synthesis, Structural Studies, and Anticancer Properties of [CuBr(PPh3)2(4,6-Dimethyl-2-Thiopyrimidine-κS]

CuBr(PPh3)2(4,6-dimethylpyrimidine-2-thione) (Cu-L) was synthesized by stirring CuBr(PPh3)3 and 4,6-dimethylpyrimidine-2-thione in dichloromethane. The crystal structure of Cu-L was obtained, and indicated that the complex adopts a distorted tetrahedral structure with several intramolecular hydrogen bonds. Moreover, a centrosymmetric dimer is formed by the intermolecular hydrogen bonding of the bromine acceptor created by symmetry operation 1−x, 1−y, 1−z to the methyl group (D3 = C42) of the pyrimidine–thione ligand. HSA-binding of Cu-L and its ligand were evaluated, revealing that Cu-L binds to HSA differently than its ligand. The HSA-bindings were modeled by molecular docking, which suggested that Cu-L binds to the II A domain while L binds between the I B and II A domains. Anticancer activities toward OVCAR-3 and HeLa cell lines were tested and indicated the significance of the copper center in enhancing the cytotoxic effect; negligible toxicities for L and Cu-L were observed towards a non-cancer cell line. The current study highlights the potential of copper(I)-phosphine complexes containing thione ligands as therapeutic agents.

Synthesis, structural characterization, docking simulation and in vitro antiproliferative activity of the new gold(III) complex with 2-pyridineethanol

Gold(III) complex containing 2-pyridineethanol has been synthesized and characterized structurally by single crystal X-ray diffraction, vibrational spectroscopy, ¹H NMR spectroscopy, electrochemical study, and DFT calculations. The Au(III) ion is four coordinated with one N-donor ligand (L) and three Cl anions. The Okuniewski's (τ'₄₌0.018) has been used to estimate the angular distortion from ideal square planar geometry. The vibrational spectroscopy studies, in the solid state and DMSO solution and cyclic voltammetry, have been performed to determine its stability and redox activity, respectively. A complete assignment of the IR and Raman spectra has been made based on the calculated potential energy distribution (PED). The theoretical calculations have been made for two functionals and several basis sets. The compound has been evaluated for its antiproliferative properties in a human lung adenocarcinoma cell line (A549), mouse colon carcinoma (CT26), human breast adenocarcinoma (MCF-7), human prostate carcinoma derived from the metastatic site in the brain (DU-145), and PANC-1 human pancreas/duct carcinoma cell line and non-tumorigenic cell lines: HaCat (human keratinocyte), and HEK293T (human embryonic kidney). Au(III) complex cytotoxicity is significantly against A549 and MCF-7 cells as in the reference drug: cisplatin. Studies of the interactions of Au(III) complex with DNA, HSA (human serum albumin) have been performed. The results from modeling docking simulations indicate that the title complex exerts anticancer effects in vitro based on different mechanisms of action to compare with cisplatin.

ROS-mediated lipid peroxidation as a result of Cu(ii) interaction with FomA protein fragments of F. nucleatum: relevance to colorectal carcinogenesis

The ability of the studied FomA protein fragments of Fusobacterium nucleatum (Fn) with copper(ii) ions (Cu(ii)-Ac-KGHGNGEEGTPTVHNE-NH2 (1Cu) and its cyclic analogue Cu(ii)-cyclo(KGHGNGEEGTPTVHNE) (2Cu)) to induce reactive oxygen species (ROS) generation, as a result of red-ox processes, was determined by UV-Vis, luminescence methods, spin trapping and cyclic voltamperometry. The contribution of 1O2 and ˙OH to DNA degradation was proved using gel electrophoresis. Furthermore, the pronounced generation of ROS by mouse colon carcinoma cells (CT26) stimulated by both copper(ii) complexes was confirmed. A fluorescence method allowed the total amounts of ROS generated inside the CT26 cells to be detected, while the spin trapping technique proved that free radicals mainly attached to the membrane surface. These last results are in agreement with the data obtained from the ICP-MS method, which demonstrates that 1Cu and 2Cu complexes are not efficiently accumulated inside the cell. Furthermore, the role of ROS in lipid peroxidation was established. The above-mentioned factors may clearly indicate the contribution of ROS generated by the studied copper(ii) complexes to colonic cell damage, which can lead to a carcinogenesis process. This study may be an important step to recognize and understand the mechanism of colon cancer initiation.

New anticandidal Cu(i) complexes with neocuproine and ketoconazole derived diphenyl(aminomethyl)phosphane: luminescence properties for detection in fungal cells

Anticandidal activity and a complex luminescence in water solutions of the new copper(i) complexes with a ketoconazole derived phosphane ligand.

Anticancer potency of novel organometallic Ir(iii) complexes with phosphine derivatives of fluoroquinolones encapsulated in polymeric micelles

A 3D model of cell culturing (spheroids) was explored and the anticancer potential of the selected novel organometallic Ir(iii) complex encapsulated in Pluronic p-123 micelles was clearly proved.

New diphenylphosphane derivatives of ketoconazole are promising antifungal agents

Four new derivatives of ketoconazole (Ke) were synthesized: diphenylphosphane (KeP), and phosphane chalcogenides: oxide (KeOP), sulphide (KeSP) and selenide (KeSeP). These compounds proved to be promising antifungal compounds towards Saccharomyces cerevisiae and Candida albicans, especially in synergy with fluconazole. Simulations of docking to the cytochrome P450 14α-demethylase (azoles’ primary molecular target) proved that the new Ke derivatives are capable of inhibiting this enzyme by binding to the active site. Cytotoxicity towards hACSs (human adipose-derived stromal cells) of the individual compounds was studied and the IC₅₀ values were higher than the MIC₅₀ for C. albicans and S. cerevisiae. KeP and KeOP increased the level of the p21 gene transcript but did not change the level of p53 gene transcript, a major regulator of apoptosis, and decreased the mitochondrial membrane potential. Taken together, the results advocate that the new ketoconazole derivatives have a similar mechanism of action and block the lanosterol 14α-demethylase and thus inhibit the production of ergosterol in C. albicans membranes.

Copper(ii) complexes based on tripodal pyridyl amine derivatives as efficient anticancer agents

The in vitro cytotoxicity of a series of chlorido-Cu(ii) complexes based on tripod pyridyl N4-donor derivatives revealed significant-to-moderate cytotoxicity against human cancer cell lines with the best results obtained for [Cu(BQPA)Cl]ClO₄/PF₆ (5-ClO4/PF6) with IC₅₀ values of 4.7–10.8 μM.

Designing anticancer copper(II) complexes by optimizing 2-pyridine-thiosemicarbazone ligands

To develop potential next-generation metal anticancer agents, we designed and synthesised five Cu(II) 2-pyridine-thiosemicarbazone complexes by modifying the hydrogen atom at the N-4 position of ligands, and then investigated their structure-activity relationships and anticancer mechanisms. Modification of the N-4 position with different groups caused significant differences in cellular uptake and produced superior antitumor activity. Cu complexes arrested the cell cycle at S phase, leading to down-regulation of levels of cyclin and cyclin-dependent kinases and up-regulation of expression of cyclin-dependent kinase inhibitors. Cu complexes exerted chemotherapeutic effects via activating p53 and inducing production of reactive oxygen species to regulate expression of the B-cell lymphoma-2 family of proteins, causing a change in the mitochondrial membrane potential and release of cytochrome c to form a dimer with apoptosis protease activating factor-1, resulting in activation of caspase-9/3 to induce apoptosis. In addition, Cu complexes inhibited telomerase by down-regulating the c-myc regulator gene and expression of the human telomerase reverse transcriptase.

[Ag(L)NO3] Complexes with 2-Benzoylpyridine-Derived Hydrazones: Cytotoxic Activity and Interaction with Biomolecules

Complexes [Ag(H2BzPh)NO₃] (1), [Ag(H2BzpCH₃Ph)NO₃] (2), [Ag(H2BzpClPh)NO₃] (3), and [Ag(H2BzpNO₂Ph)NO₃] (4) were synthesized with 2-benzoylpyridine benzoylhydrazone (H2BzPh) and its para-methyl-benzoylhydrazone (H2BzpCH₃Ph), para-chloro-benzoylhydrazone (H2BzpClPh), and para-nitro-benzoylhydrazone (H2BzpNO₂Ph) derivatives. Experimental data indicate that the nitrate ligand binds more strongly to the silver center through one of the oxygen atoms, whereas the second oxygen atom from nitrate and the hydrazone oxygen makes much weaker interactions with the metal. Dissociation of nitrate most probably occurs in solution and in biological media. Interestingly, theoretical calculations suggested that when dissociation of the nitrate takes place, all bond orders involving the metal and the atoms from the hydrazone ligand increase significantly, showing that the bonding of nitrate results in the weakening of all other interactions in the metal coordination sphere. Upon complexation of the hydrazones to silver(I), cytotoxicity against B16F10 metastatic murine melanoma cells increased in all cases. Complexes (1-3) proved to be more cytotoxic than cisplatin. All compounds were more cytotoxic to B16F10 cells than to nontumorigenic murine Melan-A melanocyte cells. Interestingly, the selectivity index (SI = IC_{50 non-malignant cells}/IC_{50 tumor cells}) of complex (1), SI = 23, was much higher than that of the parent hydrazone ligand, SI = 9.5. Studies on the interactions of complexes (1-3) with DNA suggested that although (1-3) interact with calf thymus DNA by an intercalative mode, direct covalent binding of silver(I) to DNA probably does not occur. Complexes (1-3) interact in vitro with human serum albumin indicating that these compounds could be transported by albumin.

Selective Cu(I) complex with phosphine-peptide (SarGly) conjugate contra breast cancer: Synthesis, spectroscopic characterization and insight into cytotoxic action

The main disadvantage of conventional anticancer chemotherapy is the inability to deliver the correct amount of drug directly to cancer. Those molecular delivering systems are very important to destroy cancer cells selectively. Herein we report synthesis of phosphine-peptide conjugate (Ph₂PCH₂-Sar-Gly-OH, PSG) derived from SarGly (sarcosine-glycine), which can be easily exchanged to other peptide carriers, its oxide (OPh₂PCH₂-Sar-Gly-OH, OPSG) and the first copper(I) complex ([CuI(dmp)(P(Ph)₂CH₂-Sar-Gly-OH)], 1-PSG, where dmp stands for 2,9-dimethyl-1,10-phenanthroline). The compounds were characterized by elemental analysis, NMR (1D, 2D), UV-Vis spectroscopy and DFT (Density Functional Theory) methods. PSG and 1-PSG proved to be stable in biological medium in the presence of atmospheric oxygen for several days. The cytotoxicity of the compounds and cisplatin was tested against cancer cell lines: mouse colon carcinoma (CT26; ^1-PSGIC₅₀ = 3.12 ± 0.1), human lung adenocarcinoma (A549; ^1-PSGIC₅₀ = 2.01 ± 0.2) and human breast adenocarcinoma (MCF7; ^1-PSGIC₅₀ = 0.98 ± 0.2) as well as against primary line of human pulmonary fibroblasts (MRC-5; ^1-PSGIC₅₀ = 78.56 ± 1.1). Therapeutic index for 1-PSG (MCF7) equals 80. Intracellular accumulation of 1-PSG complex increased with time and was much higher (96%) inside MCF7 cancer cells than in normal MRC5 cells (20%). Attachment of SarGly to cytotoxic copper(I) complex via phosphine motif improved selectivity of copper(I) complex 1-PSG into the cancer cells. Precise mechanistic study revealed that the 1-PSG complex causes apoptotic cells MCF7 death with simultaneous decrease of mitochondrial membrane potential and increase of caspase-9 and -3 activities. Additionally, 1-PSG generated high level of reactive oxygen species that was the reason for oxidative damages to the sugar-phosphate backbone of plasmid DNA.

Polymeric micelle-mediated delivery of half-sandwich ruthenium(II) complexes with phosphanes derived from fluoroloquinolones for lung adenocarcinoma treatment

Novel half-sandwich ruthenium(II) complexes with aminomethyl(diphenyl)phosphine derived from fluoroloquinolones (RuPCp, RuPSf, RuPLm, RuPNr) were being investigated as alternatives to well-established metal-based chemotherapeutics. All compounds were characterized by elemental analysis, selected spectroscopic methods (i.e., absorption and fluorescence spectroscopies, ESI-MS, NMR, circular dichroizm), X-ray diffractometry, ICP-MS, and electrochemical techniques. To overcome low solubility, serious side effects connected with systemic cytotoxicity of ruthenium complexes, and acquiring the resistance of cancer cells, polymeric nanoformulations based on Pluronic P-123 micelles loaded with selected Ru(II) complexes were prepared and characterized. Resulting micelles (RuPCp_M, RuPNr_M) enabled efficient drug accumulation inside human lung adenocarcinoma (A549 tumor cell line), proved by confocal microscopy and ICP-MS analysis, allowing cytotoxic action. Studied complexes exhibited promising cytotoxicity in vitro with IC50 values significantly lower than the reference drug - cisplatin. The fluorescence spectroscopic data (CT-DNA titration, in vitro cell staining) together with analysis of DNA fragmentation (pBR322 plasmid, comet assay) provided clear evidence for the interaction with DNA inducing apoptotic cell death.

CuI and CuII complexes with phosphine derivatives of fluoroquinolone antibiotics - A comparative study on the cytotoxic mode of action

In this paper, we present a comparative study on the cytotoxic mode of action of copper(I) and copper(II) complexes with phosphine derivatives of fluoroquinolone antibiotics (ciprofloxacin HCp and norfloxacin HNr). The in vitro cytotoxic activity of four new compounds was tested against two selected cancer cell lines. All complexes exhibited much better cytotoxicity against both cell lines than unmodified fluoroquinolone antibiotics, their phosphines (PCp, PNr), chalcogenide derivatives (oxides: OPCp, OPNr; sulfides: SPCp, SPNr and selenides: SePCp, SePNr) and previously described by us complexes with phosphines derived from different fluoroquinolones: lomefloxacin (HLm) and sparfloxacin (HSf) as well as cisplatin. Apoptosis, observed at a great predominance, was induced by all studied complexes. Importantly, it was concluded that coordination compounds with Cu(I) ion ([Cu^I-PNr] and [Cu^I-PCp]) were much more active than those with Cu(II) ion ([OPNr-Cu^II], [OPCp-Cu^II]), even though the highest efficacy to produce reactive oxygen species, participating in overall cytotoxicity, was proved for copper(II) complexes among all studied compounds. Herein, we discuss not only results obtained for copper(I)/(II) complexes with phosphines derived from HNr and HCp but we also compare them to previously described data for complexes with HLm and HSf derivatives. This is the first insight into a structure-activity relationship of copper complexes with phosphine derivatives of fluoroquinolone antibiotics.

Copper(i) complexes with phosphine derived from sparfloxacin. Part III: multifaceted cell death and preliminary study of liposomal formulation of selected copper(i) complexes

Apoptosis induced by copper(i) complexes is connected to caspase-dependent mitochondrial pathways supported by ROS production and irreversible DNA fragmentation.

Copper(II) complexes based on tripodal pyrazolyl amines: Synthesis, structure, magnetic properties and anticancer activity

The Cu(II) complexes [Cu(bpdmpz)Cl]ClO₄ (1), [Cu(bdmpzp)Cl]ClO₄ (2-ClO₄), [Cu(bdmpzp)Cl]PF₆ (2-PF₆) and [Cu(tdmpza)Cl]ClO₄ (3), bpdmpzp=[bis[((2-pyridylmethyl)-di(3,5-dimethyl-1H-pyrazolyl)methyl)]amine, bdmpzp=[bis((di(3,5-dimethyl-1H-pyrazolyl)methyl)-(2-pyridylmethyl)]amine and tdmpza=tris[di(3,5-dimethyl-1H-pyrazolyl)-methyl)]amine were synthesized and characterized by elemental analysis, magnetic and conductivity measurements, electrospray-ionization mass spectrometry, infrared and electronic spectroscopy, and X-ray crystallography. The magnetic properties of the complexes, measured at variable temperature, revealed weak antiferromagnetic intermolecular interactions. The cytotoxicity of the complexes 1, 2-ClO₄, 3, and 4 ([Cu(bedmpzp)Cl]PF₆, where bedmpzp=[bis(3,5-dimethyl-1H-pyrazol-1-yl-1-ethyl)-(2-pyridylmethyl)]amine), was investigated against four human cancer cell lines: A2780 (ovarian), A2780R (cisplatin-resistant variant), HOS (aggressive bone tumors), CaCo2 (epithelial colorectal adenocarcinoma) and on healthy human hepatocytes. The complex 4 was the most cytotoxic one, with IC₅₀=1.4μM (A2780), 8.3μM (A2780R), 4.7μM (HOS) and 10.8μM (CaCo2). The mass spectrometry-based interaction studies, involving selected sulfur-containing biomolecules and small model proteins, revealed pro-oxidant effects of complexes 1 and 4 and differences in stability of both complexes in the mixtures containing the model protein cytochrome c after 24h incubation, complex 1 formed 1:1 adduct, the formation of which was accompanied by the loss of one dimethylpyrazole pendant arm from the bpdmpz ligand, while the complex 4 composition remained intact and the complex formed both 1:1 and 1:2 adducts (cytochrome c vs. Cu(II)-complex).