Search for new biologically active compounds: in vitro studies of antitumor and antimicrobial activity of dirhodium(II,II) paddlewheel complexes

Four neutral Rh1-Rh4 complexes of the general formula [Rh2(CH3COO)4L2], where L is an N-alkylimidazole ligand, were synthesized and characterized using various spectroscopic techniques, and in the case of Rh4 the crystal structure was confirmed. Investigation of the interactions of these complexes with HSA by fluorescence spectroscopy revealed that the binding constants Kb are moderately strong (∼104 M-1), and site-marker competition experiments showed that the complexes bind to Heme site III (subdomain IB). Competitive binding studies for CT DNA using EB and HOE showed that the complexes bind to the minor groove, which was also confirmed by viscosity experiments. Molecular docking confirmed the experimental data for HSA and CT DNA. Antimicrobial tests showed that the Rh2-Rh4 complexes exerted a strong inhibitory effect on G+ bacteria B. cereus and G- bacteria V. parahaemolyticus as well as on the yeast C. tropicalis, which showed a higher sensitivity compared to fluconazole. The cytotoxic activity of Rh1-Rh4 complexes tested on three cancer cell lines (HeLa, HCT116 and MDA-MB-231) and on healthy MRC-5 cells showed that all investigated complexes elicited more efficient cytotoxicity on all tested tumor cells than on control cells. Investigation of the mechanism of action revealed that the Rh1-Rh4 complexes inhibit cell proliferation via different mechanisms of action, namely apoptosis (increase in expression of the pro-apoptotic Bax protein and caspase-3 protein in HeLa and HCT116 cells; changes in mitochondrial potential and mitochondrial damage; release of cytochrome c from the mitochondria; cell cycle arrest in G2/M phase in both HeLa and HCT116 cells together with a decrease in the expression of cyclin A and cyclin B) and autophagy (reduction in the expression of the protein p62 in HeLa and HCT116 cells).

Copper(II) Complexes with 2,2':6',2″-Terpyridine Derivatives Displaying Dimeric Dichloro-μ-Bridged Crystal Structure: Biological Activities from 2D and 3D Tumor Spheroids to In Vivo Models

Eight 2,2':6',2″-terpyridines, substituted at the 4'-position with aromatic groups featuring variations in π-conjugation, ring size, heteroatoms, and methoxy groups, were employed to enhance the antiproliferative potential of [Cu2Cl2(R-terpy)2](PF6)2. Assessing the cytotoxicity in A2780 (ovarian carcinoma), HCT116 (colorectal carcinoma), and HCT116DoxR (colorectal carcinoma resistant to doxorubicin) and normal primary fibroblasts revealed that Cu(II) complexes with 4-quinolinyl, 4-methoxy-1-naphthyl, 2-furanyl, and 2-pyridynyl substituents showed superior therapeutic potential in HCT116DoxR cells with significantly reduced cytotoxicity in normal fibroblasts (42-129× lower). Besides their cytotoxicity, the Cu(II) complexes are able to increase intracellular ROS and interfere with cell cycle progression, leading to cell death by apoptosis and autophagy. Importantly, they demonstrated antimetastatic and antiangiogenic properties without in vivo toxicity. In accordance with their nuclear accumulation, the Cu(II) complexes are able to cleave pDNA and interact with bovine serum albumin, which is a good indication of their ability for internalization and transport toward tumor cells.

In vitro and in vivo antitumor activities of Ru and Cu complexes with terpyridine derivatives as ligands

Six terpyridine ligands(L1-L6) with chlorophenol or bromophenol moiety were obtained to prepare metal terpyridine derivatives complexes: [Ru(L1)(DMSO)Cl2] (1), [Ru(L2)(DMSO)Cl2] (2), [Ru(L3)(DMSO)Cl2] (3), [Cu(L4)Br2]·DMSO (4), Cu(L5)Br2 (5), and [Cu(L6)Br2]⋅CH3OH (6). The complexes were fully characterized. Ru complexes 1-3 showed low cytotoxicity against the tested cell lines. Cu complexes 4-6 exhibited higher cytotoxicity against several tested cancer cell lines compared to their ligands and cisplatin, and lower toxicity towards normal human cells. Copper(II) complexes 4-6 arrested T-24 cell cycle in G1 phase. The mechanism studies indicated that complexes 4-6 accumulated in mitochondria of T-24 cells and caused significant reduction of the mitochondrial membrane potential, increase of the intracellular ROS levels and the release of Ca2+, and the activation of the Caspase cascade, finally inducing apoptosis. Animal studies showed that complex 6 obviously inhibited the tumor growth in a mouse xenograft model bearing T-24 tumor cells without significant toxicity.

Silver complexes with substituted terpyridines as promising anticancer metallodrugs and their crystal structure, photoluminescence, and DNA interactions

Six silver hexafluoroantimonate complexes (1-6) with 4'-(4'-substituted-phenyl)-2,2':6',2''-terpyridine compounds bearing hydrogen (L1), methyl (L2), methylsulfonyl (L3), chloro (L4), bromo (L5) and iodo (L6) were prepared and characterized by 1H NMR, 13C NMR, IR, elemental analysis and single crystal X-ray diffraction. All the compounds exhibit interesting photoluminescence properties in the solid state and solution. In vitro data demonstrate that all of them show higher antiproliferative activities than cisplatin against three human carcinoma cell lines, A549, Eca-109 and MCF-7. Compound 3 exhibits the lowest IC50 value (2.298 μM) against A549 cell lines, which is 2.963 μM for 4 against Eca-109 and 1.830 μM for 1 against MCF-7. For silver halogen-substituted terpyridine compounds, their anticancer activities decrease following the sequence of -Cl, -Br, and -I substituents. The comparison results show that their anticancer activity is significantly higher than that of their free ligands. The DNA interaction was studied by fluorescence titration, circular dichroism spectroscopy and molecular modeling methods. Spectrophotometric results reveal that the compounds have strong affinity binding with DNA as intercalators and molecular docking studies indicate that the binding is contributed by the π-π stacking and hydrogen bonds. The DNA binding ability of the complexes has been correlated with their anticancer activities, which could potentially provide a new rationale for the future design of terpyridine-based metal complexes with antitumor potential.

Antitumor activity of synthetic three copper(II) complexes with terpyridine ligands

Three new synthetic terpyridine copper(II) complexes were characterized. The copper(II) complexes induced apoptosis of three cancer cell lines and arrested T-24 cell cycle in G1 phase. The complexes were accumulated in mitochondria of T-24 cells and caused significant reduction of the mitochondrial membrane potential. The complexes increased both intracellular ROS and Ca²⁺ levels and activated the caspase-3/9 expression. The apoptosis was further confirmed by Western Blotting analysis. Bcl-2 was down-regulated and Bax was upregulated after treatment with complexes 1-3. The in vivo studies showed that complexes 1-3 obviously inhibited the growth of tumor without significant toxicity to other organs.

Recent development of gold(I) and gold(III) complexes as therapeutic agents for cancer diseases

Metal complexes have demonstrated significant antitumor activities and platinum complexes are well established in the clinical application of cancer chemotherapy. However, the platinum-based treatment of different types of cancers is massively hampered by severe side effects and resistance development. Consequently, the development of novel metal-based drugs with different mechanism of action and pharmaceutical profile attracts modern medicinal chemists to design and synthesize novel metal-based agents. Among non-platinum anticancer drugs, gold complexes have gained considerable attention due to their significant antiproliferative potency and efficacy. In most situations, the gold complexes exhibit anticancer activities by targeting thioredoxin reductase (TrxR) or other thiol-rich proteins and enzymes and trigger cell death via reactive oxygen species (ROS). Interestingly, gold complexes were recently reported to elicit biochemical hallmarks of immunogenic cell death (ICD) as an ICD inducer. In this review, the recent progress of gold(I) and gold(III) complexes is comprehensively summarized, and their activities and mechanism of action are documented.

Discovery of thirteen cobalt(II) and copper(II) salicylaldehyde Schiff base complexes that induce apoptosis and autophagy in human lung adenocarcinoma A549/DDP cells and that can overcome cisplatin resistance in vitro and in vivo

In this study, 13 transition metal complexes, namely, [Cu(L¹H)(H₂O)₂]·(H₂O)·NO₃ (1), [Cu(LⁿH₂)₂]·(NO₃)·(H₂O)₂ (2, n = 2; 3, n = 3; 4, n = 4; 5, n = 5), [Co(LⁿH)₂]₂·(H₂O)_0.5 (6, n = 2; 7, n = 3; 8, n = 4; 9, n = 5), [Cu(L⁶H)_0.5(L¹⁰H)_0.5(phen)]·(CH₃OH)_0.25 (10), [Cu(L¹¹H) (phen)]₄·(H₂O)₉ (11), [Cu(L⁸H)_0.27(L¹²H)_0.73(phen)]₄·(H₂O)_5.5(CH₃OH) (12), and [Cu(L⁹H) (phen)]₃·(H₂O)₇·(CH₃OH) (13), were synthesized using Schiff base ligands and characterized by elemental analysis (EA), infrared spectroscopy (IR), and single-crystal X-ray diffraction (SC-XRD). Compared with complexes 1-9, complexes 10-13 displayed stronger cytotoxic activities against the tested A549/DDP cancer cells (IC₅₀ = 0.97-3.31 μM), with differences greater than one order of magnitude. Moreover, complexes 11 and 13 could induce apoptosis and autophagy in A549/DDP cells via the mitochondrial dysfunction pathway that affects the regulation of autophagy- and mitochondrial-related proteins. Importantly, the results indicate that the two novel salicylaldehyde Schiff base analogs, 11 and 13, exhibited pronounced and selective activity against A549/DDP xenografts in vivo.

Terpyridines as promising antitumor agents: an overview of their discovery and development

INTRODUCTION

The fused aromatic system of terpyridines makes them good, innocent ligands for various metals. The resulting complexes have been extensively studied for both their biological activity and physico-chemical properties. However, although free ligands also have an interesting biological activity, their share in recent research is considerably limited.

AREAS COVERED

This review covers the literature on the anticancer activity of terpyridines with special attention being paid to their use as free ligands. Whenever possible, the mechanism of action has been discussed, thereby providing evidence of the substantial differences between sole ligands or less stable complexes and those that have heavier elements.

EXPERT OPINION

The existing literature indicates that there is a specific attitude for investigating terpyridines and their transition metal complexes. While the latter have been well explored and recognized in the scientific community, the free terpyridines are considered to be useful solely due to their complexing ability. At the same time, terpyridines could have similar or even higher anticancer potency than their complexes. Moreover, a mechanistic analysis of the stability and intracellular activity would provide information that would be useful for designing new drugs.

New Non-Toxic N-alkyl Cholinium-Based Ionic Liquids as Excipients to Improve the Solubility of Poorly Water-Soluble Drugs

In this work, we prepared new biocompatible N-alkyl cholinium-based ionic liquids to be used as cosolvents to improve the solubility of poorly water-soluble drugs, namely, sodium diclofenac and paracetamol. In this set of ionic liquids, we intend to understand the effect of increasing the asymmetry of the ionic liquid cation/anion by growing the length of one of the alkyl chains attached to the nitrogen center/sulfonate center on the dissolution capacity of the ionic liquid. The addition of these new ionic liquids to water increased the dissolution capacity of the drugs up to four-times that in water, and improved the pharmacodynamic properties of these drugs, especially the case of sodium diclofenac. The intermolecular interactions between the drugs and ionic liquids were investigated by NMR. Two-dimensional 1H/1H nuclear overhauser effect spectroscopy (NOESY) revealed an interaction between sodium diclofenac and the alaninate anion from the [C2Ch]2[SucAla]. In the case of paracetamol and [C4Ch][C2SO3], it was possible to observe two intermolecular interactions between the hydroxyl group of paracetamol and two protons from the cation [C4Ch]+. Interestingly, the ionic liquid bearing a succinyl-DL-alaninate anion, [SucAla]2−, and a N-ethyl cholinium cation, [C2Ch]+, which presented the highest ability to dissolve sodium diclofenac, showed no cytotoxicity up to 500 mM. Therefore, this ionic liquid is a potential candidate for drug delivery applications.

Comparing Metal-Halide and -Oxygen Adducts in Oxidative C/O-H Activation: AuIII-Cl versus AuIII-OH

High-valent metal–halides have come to prominence as highly effective oxidants. A direct comparison of their efficacy against that of traditional metal–oxygen adducts is needed. [Au^III(Cl)(terpy)](ClO₄)₂ (1; terpy = 2,2′:6′,2-terpyridine) readily oxidized substrates bearing O–H and C–H bonds via a hydrogen atom transfer mechanism. A direct comparison with [Au^III(OH)(terpy)](ClO₄)₂ (2) showed that 1 was a kinetically superior oxidant with respect to 2 for all substrates tested. We ascribe this to the greater thermodynamic driving force imbued by the Cl ligand versus the OH ligand.

We report a direct comparison of the efficacy of metal−halide oxidants to those of traditional metal−oxygen adducts. Au^III−Cl and Au^III−OH oxidants, supported by the same ancillary ligand, readily oxidized substrates via a hydrogen atom transfer mechanism. The Au^III−Cl oxidant was kinetically superior for all substrates. We ascribed this to the greater thermodynamic driving force imbued by the Cl ligand versus the OH ligand.

Square planar Au(III), Pt(II) and Cu(II) complexes with quinoline-substituted 2,2':6',2″-terpyridine ligands: From in vitro to in vivo biological properties

Cancer is the second leading cause of death worldwide. Cisplatin has challenged cancer treatment; however, resistance and side effects hamper its use. New agents displaying improved activity and more reduced side effects relative to cisplatin are needed. In this work we present the synthesis, characterization and biological activities of three complexes with quinoline-substituted 2,2':6',2″-terpyridine ligand: [Pt(4'-(2-quin)-terpy)Cl](SO₃CF₃) (1), [Au(4'-(2-quin)-terpy)Cl](PF₆)₂·CH₃CN (2) and [Cu(4'-(2-quin)-terpy)Cl](PF₆) (3). The three complexes displayed a high antiproliferative activity in ovarian carcinoma cell line (A2780) and even more noticeable in a colorectal carcinoma cell line (HCT116) following the order 3 > 2 > 1. The complexes IC₅₀ are at least 20 × lower than the IC₅₀ displayed by cisplatin (15.4 μM) in HCT116 cell line while displaying at the same time, much reduced cytotoxicity in a normal dermal fibroblast culture. These cytotoxic activities seem to be correlated with the inclination angles of 2-quin unit to the central pyridine. Interestingly, all complexes can interact with calf-thymus DNA (CT-DNA) in vitro via different mechanisms, although intercalation seems to be the preferred mechanism at least for 2 and 3 at higher concentrations of DNA. Moreover, circular dichroism (CD) data seems to indicate that complex 3, more planar, induces a high destabilization of the DNA double helix (shift from B-form to Z-form). Higher the deviation from planar, the lower the cytotoxicity displayed by the complexes. Cellular uptake may be also responsible for the different cytotoxicity exhibited by complexes with 3 > 2 >1. Complex 2 seems to enter cells more passively while complex 1 and 3 might enter cells via energy-dependent and -independent mechanisms. Complexes 1-3 were shown to induce ROS are associated with the increased apoptosis and autophagy. Moreover, all complexes dissipate the mitochondrial membrane potential leading to an increased BAX/BCL-2 ratio that triggered apoptosis. Complexes 2 and 3 were also shown to exhibit an anti-angiogenic effect by significantly reduce the number of newly formed blood vessel in a CAM model with no toxicity in this in vivo model. Our results seem to suggest that the increased cytotoxicity of complex 3 in HCT116 cells and its potential interest for further translation to pre-clinical mice xenografts might be associated with: 1) higher % of internalization of HCT116 cells via energy-dependent and -independent mechanisms; 2) ability to intercalate DNA and due to its planarity induced higher destabilization of DNA; 3) induce intracellular ROS that trigger apoptosis and autophagy; 4) low toxicity in an in vivo model of CAM; 5) potential anti-angiogenic effect.

Copper(ii) complexes with tridentate halogen-substituted Schiff base ligands: synthesis, crystal structures and investigating the effect of halogenation, leaving groups and ligand flexibility on antiproliferative activities

To investigate the effect of different halogen substituents and leaving groups and the flexibility of ligands on the anticancer activity of copper complexes, sixteen copper(ii) complexes with eight different tridentate Schiff-base ligands containing pyridine and 3,5-halogen-substituted phenol moieties were synthesized and characterized by spectroscopic methods. Four of these complexes were also characterized by X-ray crystallography. The cytotoxicity of the complexes was determined in three different tumor cell lines (i.e. the A2780 ovarian, HCT116 colorectal and MCF7 breast cancer cell line) and in a normal primary fibroblast cell line. Complexes were demonstrated to induce a higher loss of cell viability in the ovarian carcinoma cell line (A2780) with respect to the other two tumor cell lines, and therefore the biological mechanisms underlying this loss of viability were further investigated. Complexes with ligand L₁ (containing a 2-pycolylamine-type motif) were more cytotoxic than complexes with L₂ (containing a 2-(2-pyridyl)ethylamine-type motif). The loss of cell viability in A2780 tumor cells was observed in the order Cu(Cl₂-L₁)NO₃ > Cu(Cl₂-L₁)Cl > Cu(Br₂-L₁)Cl > Cu(BrCl-L₁)Cl. All complexes were able to induce reactive oxygen species (ROS) that could be related to the loss of cell viability. Complexes Cu(BrCl-L₁)Cl and Cu(Cl₂-L₁)NO₃ were able to promote A2780 cell apoptosis and autophagy and for complex Cu(BrCl-L₁)Cl the increase in apoptosis was due to the intrinsic pathway. Cu(Cl₂-L₁)Cl and Cu(Br₂-L₁)Cl complexes lead to cellular detachment allowing to correlate with the results of loss of cell viability. Despite the ability of the Cu(BrCl-L₁)Cl complex to induce programmed cell death in A2780 cells, its therapeutic window turned out to be low making the Cu(Cl₂-L₁)NO₃ complex the most promising candidate for additional biological applications.

Cu(I) complexes as new antiproliferative agents against sensitive and doxorubicin resistant colorectal cancer cells: synthesis, characterization, and mechanisms of action

Cancer is one of the worst health issues worldwide, representing the second leading cause of death. Current chemotherapeutic drugs face some challenges like the acquired resistance of the tumoral cells and low specificity leading to unwanted side effects. There is an urgent need to develop new compounds that may target resistant cells. The synthesis and characterization of two Cu(i) complexes of general formula [Cu(PP)(LL)][BF4], where PP is a phosphane ligand (triphenylphosphine or 1,2-bis(diphenylphosphano) ethane) and LL = is a heteroaromatic bidentate ligand (4,4'-dimethyl-2,2'-bipyridine and 6,3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine). The new compounds were fully characterized by spectroscopic techniques (NMR, FTIR and UV-vis.), elemental analysis (C, H, N and S) and two structures were determined by single X-ray diffraction studies. The antiproliferative potential of the new Cu(i) complexes were studied in tumor (breast adenocarcinoma, ovarian carcinoma and in colorectal carcinoma sensitive and resistant to doxorubicin) and normal (fibroblasts) cell lines. Complexes 1-4 did not show any antiproliferative potential. Amongst the complexes 5-8, complex 8 shows high cytotoxic potential against colorectal cancer sensitive and resistant to doxorubicin and low cytotoxicity towards healthy cells. We show that complexes 5-8 can cleave pDNA and, in particular, the in vitro pDNA cleavage is due to an oxidative mechanism. This oxidative mechanism corroborates the induction of reactive oxygen species (ROS), that triggers HCT116 cell death via apoptosis, as proved by the increased expression of BAX protein relative to BCL-2 protein and the depolarization of mitochondrial membrane potential, and via autophagy. Additionally, complex 8 can block the cell cycle in the G1 phase, also exhibiting a cytostatic potential. Proteomic analysis confirmed the apoptotic, autophagic and cytostatic potential of complex 8, as well as its ability to produce ROS and cause DNA damage. The interference of the complex in folding and protein synthesis and its ability to cause post-translational modifications was also verified. Finally, it was observed that the complex causes a reduction in cellular metabolism. The results herein demonstrated the potential of Cu(i) complexes in targeting doxorubicin sensitive and resistant cells which is positive and must be further explored using in vivo animal models.

Transition metal decorated soft nanomaterials through modular self-assembly of an asymmetric hybrid polyoxometalate

An asymmetrically functionalised Wells-Dawson organic-inorganic hybrid polyoxometalate has been post-functionalised by Pt²⁺ coordination, and demonstrates self-assembly into surface-decorated micellar nanostructures. This multifunctional hybrid material is found to be a redox-active soft nanomaterial and demonstrates a new molecular design strategy with potential for applications in photo- or electro-catalysis.

Hydrogen Atom Transfer Oxidation by a Gold-Hydroxide Complex

Au^III-oxygen adducts have been implicated as intermediates in homogeneous and heterogeneous Au oxidation catalysis, but their reactivity is under-explored. Complex 1, ([Au^III(OH)(terpy)](ClO₄)₂, (terpy = 2,2':6',2-terpyridine), readily oxidized substrates bearing C-H and O-H bonds. Kinetic analysis revealed that the oxidation occurred through a hydrogen atom transfer (HAT) mechanism. Stable radicals were detected and quantified as products of almost quantitative HAT oxidation of alcohols by 1. Our findings highlight the possible role of Au^III-oxygen adducts in oxidation catalysis and the capability of late transition metal-oxygen adducts to perform proton coupled electron transfer.

Antiproliferative Activities of Diimine-Based Mixed Ligand Copper(II) Complexes

A series of Cu(diimine)(X-sal)(NO₃) complexes, where the diimine is either 2,2'-bipyridine (bpy) or 1,10-phenanthroline (phen) and X-sal is a monoanionic halogenated salicylaldehyde (X = Cl, Br, I, or H), have been synthesized and characterized by elemental analysis and X-ray crystallography. Penta-coordinate geometries copper(II) were observed for all cases. The influence of the diimine coligands and different halogen atoms on the antiproliferative activities toward human cancer cell lines have been investigated. All Cu(II) complexes were able to induce a loss of A2780 ovarian carcinoma cell viability, with phen derivatives more active than bpy derivatives. In contrast, no in vitro antiproliferative effects were observed against the HCT116 colorectal cancer cell line. These cytotoxicity differences were not due to a different intracellular concentration of the complexes determined by inductively coupled plasma atomic emission spectroscopy. A small effect of different halogen substituents on the phenolic ring was observed, with X = Cl being the most highly active toward A2780 cells among the phen derivatives, while X = Br presented the lowest IC₅₀ in A2780 cells for bpy analogs. Importantly, no reduction in normal primary fibroblasts cell viability was observed in the presence of bpy derivatives (IC₅₀ > 40 μM). Mechanistically, complex 1 seems to induce a stronger apoptotic response with a higher increase in mitochondrial membrane depolarization and an increased level of intracellular reactive oxygen species (ROS) compared to complex 3. Together, these data and the low IC₅₀ compared to cisplatin in A2780 ovarian carcinoma cell line demonstrate the potential of these bpy derivatives for further in vivo studies.

In vitro antiproliferative effect of vanadium complexes bearing 8-hydroxyquinoline-based ligands – the substituent effect

This is the first comprehensive study demonstrating the antiproliferative effect of vanadium complexes bearing 8-hydroxyquinoline (quinH) ligands, including the parent and –CH₃ (Me), –NO₂, –Cl and –I substituted ligands, on HCT116 and A2780 cancer cell lines.

Platinum(II) coordination compounds with 4'-pyridyl functionalized 2,2':6',2″-terpyridines as an alternative to enhanced chemotherapy efficacy and reduced side-effects

Two platinum(II) coordination compounds, [PtCl(4'-R¹-terpy)](SO₃CF₃) (1) and [PtCl(4'-R²-terpy)](SO₃CF₃) (2), with 4'-(2-pyridyl)-2,2':6',2″-terpyridine (4'-R¹-terpy) or 4'-(3-pyridyl)-2,2':6',2″-terpyridine (4'-R²-terpy) were synthesized and the impact of the pendant pyridyl ring on the structure and cytotoxic activity of Pt(II)-terpyridine complexes was explored. The single-crystal X-ray diffraction analysis confirmed square planar coordination of the cations [PtCl(4'-Rⁿ-terpy)]⁺. The mode of binding of 1 and 2 to calf thymus DNA was examined by UV-Vis absorption titration, ethidium displacement assay and reaction with 9-ethylguanine, and the mixed covalent-intercalative mode was demonstrated. The cytotoxicity of the Pt(II) complexes against six cancer cell lines and three normal ones was determined using MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay and compared to cisplatin. The IC₅₀ values for the compound 2 towards the cancer cell lines are in the low micromolar range. Most remarkably, 2 was over 4 times more effective than 1 and cisplatin against non-small lung adenocarcinoma (A549), and its selectivity index was ~60-80 times higher than that for 1 and cisplatin. The mechanisms underlying the loss of viability under treatment of 2 was further investigated including F-actin staining, mitotic index analysis, cytometric cell cycle analysis, Fluorescein isothiocyanate (FITC) -conjugated Annexin V antibody and propidium iodide (PI) staining, measurements of reactive oxygen species (ROS) in cells, analysis of changes in the mitochondrial mass and potential and quantitative real time polymerase chain reaction (qRT-PCR) genes analysis. The compound 2 was found to have a pro-oxidative effect by strong stimulation of cells for the production of reactive oxygen species and cytostatic effect through cell cycle arrest.

Platinum(ii) complexes showing high cytotoxicity toward A2780 ovarian carcinoma cells

2,6-Bis(thiazol-2-yl)pyridines functionalized with 9-anthryl (L¹), 9-phenanthryl (L²), and 1-pyrenyl (L³) groups were used for the preparation of [Pt(Lⁿ)Cl]CF₃SO₃ (1-3). The constitution of the Pt(ii) complexes was determined by ¹H and ¹³C NMR spectroscopy, HR-MS spectrometry, elemental analysis and X-ray analysis (for (1)). The electrochemical and photophysical properties of [Pt(Lⁿ)Cl]CF₃SO₃ were compared with the behaviour of the Pt(ii) complexes with aryl-substituted 2,2':6',2''-terpyridine ligands. What is noteworthy is that the coordination ability of dtpy toward the Pt(ii) centre was investigated for the first time. All complexes were tested in vitro by MTS assay on four tumor cell lines, A2780 (ovarian carcinoma), HTC116 (colon rectal carcinoma), MCF7 (breast adenocarcinoma), and PC3 (prostate carcinoma) and on normal primary fibroblasts. Compounds (1-3) showed a dose dependent antiproliferative effect in the A2780 cell line with (3) > (2) > (1) and this loss of A2780 cell viability was due to a combination of an apoptotic cell death mechanism via mitochondria and autophagic cell death. Exposure to IC₅₀ concentration of (2) induced an increase in the number of apoptotic nuclei and a depolarization of the mitochondrial membrane which is consistent with the induction of apoptosis while exposure to IC₅₀ concentration of (3) showed an increase in the apoptotic nuclei with a slight hyperpolarization of the mitochondrial membrane that might indicate an initial step of apoptosis induction. The complexes (2) and (3) induce an increase in the production of intracellular ROS which is associated with the trigger of the apoptotic pathways. The ROS production was augmented by the presence of oxidants and correlated with an increase of oxygen radicals. The IC₅₀ of (2) and (3) (4.4 μM and 2.9 μM, respectively) was similar to the IC₅₀ of cisplatin (3.4 μM) in the A2780 cell line, which together with their low cytotoxicity in normal fibroblasts, demonstrates their potential for further studies.

Copper(ii) complexes with 2,2′:6′,2′′-terpyridine, 2,6-di(thiazol-2-yl)pyridine and 2,6-di(pyrazin-2-yl)pyridine substituted with quinolines. Synthesis, structure, antiproliferative activity, and catalytic activity in the oxidation of alkanes and alcohols with peroxides

The toxicity of six new Cu(ii) complexes was evaluated in cancer derived cell lines. A model of competitive interaction of hydroxyl radicals with CH₃CN and RH in the catalyst cavity has been proposed.

Understanding the molecular orientation growth on a nanometer scale and adjustable electron transition performance of a terpyridyl derivative under different external environments

TD-DFT calculation is used to forecast the aggregation style of PYTPY under different external conditions and predict the related morphology and electron transition performance.