Mixed-ligand Cu(II) hydrazone complexes designed to enhance anticancer activity

New metal complexes of 1H-benzimidazole-2-yl hydrazones: Cytostatic, proapoptotic and modulatory activity on kinase signaling pathways

The copper complexes of two 1H-benzimidazole-2-yl hydrazones were obtained by complexation with copper chloride. The molecular structure of the complexes was studied by microchemical analysis, SEM-EDX, IR and micro-Raman spectroscopy and DFT calculations. It was found that both ligands form 1:1 complexes with the copper, where the Cu ions are coordinated by N-atom from the benzimidazole ring, N-atom of the azomethine bond, O-atom from the ortho-OH group of the aromatic ring and one chlorine atom. The coordination process significantly affected their cytotoxicity profile. The conversion of 2-(2-hydroxybenzylidene)-1-(1H-benzimidazol-2-yl)hydrazine 1.1. into a Cu complex 2.1. led to a 2.4-fold increase in its antileukemic activity against AR-230 cells and an 8-fold increase in the cytostatic activity against MCF-7 breast cancer cell line. The growth-inhibitory effect of the Cu complex of 2-(2-hydroxy-4-methoxybenzylidene)-1-(1H-benzimidazol-2-yl)hydrazine 2.2. on the MCF-7 cells was comparable to that of the respective ligand, however lacked towards the leukemic AR-230 cell population. Regarding their cytotoxic potential towards CCL-1 cells, both Cu complexes exhibited a weaker selectivity pattern as compared to their ligands. The proapoptotic and modulatory activity of 1.1 and 2.1. on key kinase signaling pathways was further studied in the ER + breast cancer (MCF-7) and bcr-abl + leukemic (AR-230) in vitro tumor models in a comparative manner to the reference drugs tamoxifen and imatinib, respectively. Inhibition of the JAK/STAT signaling pathway was outlined as a prominent mechanism in the antileukemic activity against the Ph + AR-230 in vitro model, whereas recruitment and activation of the extrinsic apoptotic pathway was established in the MCF-7 cells.

Copper(II) complexes containing hydrazone and bipyridine/phenanthroline ligands for anticancer application against breast cancer cells

In this work, mixed ligand Cu(II) complexes containing hydrazone and bipyridine ligands (CB1-CB5), or hydrazone and phenanthroline ligands (CP1-CP5) have been synthesized and characterized by spectroscopic and analytical techniques. Single crystal X-ray structure of complex CB1 revealed that two nitrogen atoms from bipyridine, one carbonyl oxygen, one azomethine nitrogen and one hydroxyl oxygen from the hydrazone ligand coordinated to Cu(II) ion, adopting a distorted square pyramidal geometry. Interaction of these complexes with calf thymus (CT) DNA and bovine serum albumin (BSA) was analyzed by absorption and emission studies. Further, the in vitro anticancer activity of the complexes was investigated exclusively against the breast cancer cells namely MCF7, T47D and MDA MB 231, and a normal breast MCF 10a cell line. The phenanthroline bearing complexes (CP1-CP5) displayed better activity than their bipyridine counterparts as seen from the IC50 values. In addition, the most active complex CP1 having an IC50 value of 5.8 ± 0.3 μM against T47D cancer cells was investigated for its mode of cell death through acridine orange/ethidium bromide(AO/EB), 4',6-diamidino-2-phenylindole (DAPI) and Annexin-V fluorescein isothiocyanate (FITC) staining assays which revealed apoptosis. Lastly, the cell cycle analysis revealed that complex CP1 induced cell death in T47D cancer cells at the G0/G1 phase.

Hydrazone copper(II) complexes suppressed lung adenocarcinoma by activating multiple anticancer pathway

Activating multiple anti-cancer pathways has great potential for tumor treatment. Herein, we synthesized two binuclear Cu(II) hydrazone complexes ([Cu2(HL1)2Cl2] 1 and [Cu2(HL1)2Br2] 2) and two mononuclear hydrazone-Cu(II) complexes ([Cu(HL2)Cl]·CH3OH 3 and [Cu(HL2)(H2O)Br]·2H2O 4), to evaluate their anti-lung cancer activities. MTT assays revealed that the Cu(II) complexes demonstrate superior anticancer activity compared to cisplatin. Among them, complex 3 exhibited selective toxicity towards A549 cancer cells in comparison to normal cells and demonstrated hemolytic activity comparable to cisplatin. The low toxicity and effective antitumor capabilities of complex 3 have been confirmed in xenograft experiments using A549 tumor-bearing mice. Interestingly, complex 3 eradicates lung tumor cells both in vivo and in vitro by initiating multiple anticancer pathways, including cuproptosis. Our research extends the study of hydrazone copper complexes and provides strategies for the treatment of lung cancer.

A novel copper(II) complex with a salicylidene carbohydrazide ligand that promotes oxidative stress and apoptosis in triple negative breast cancer cells

We report the synthesis, characterization, anti-cancer activity and mechanism of action of a novel water-soluble Cu(II) complex with salicylidene carbohydrazide as the ligand and o-phenanthroline as the co-ligand. The synthesized complex (1) was characterized by FT-IR, EPR, and electronic spectroscopy, as well as single crystal X-ray diffraction. This compound was found to be paramagnetic from EPR spectra and X-ray crystallography revealed that the molecule crystallized in an orthorhombic crystal system. The crystal lattice was asymmetric containing two distinct binuclear copper complexes containing the Schiff base as the major ligand, o-phenanthroline as a co-ligand, two nitrate anions, and two water molecules. The Cu(II) in the first site coordinated with the enolised ligand comprising enolate O-, phenolate O-, and the imine N and N,N from o-phen. The major part of this complex exists as Cu(II) coordinated with two H2O molecules at the second site with nitrate acting as the counter anion. However, a smaller portion of the complex exists where Cu(II) is coordinated with NO3- and H2O, and the remaining water molecule acts as lattice water. It was tested for DNA binding and cleavage properties which revealed that it binds in an intercalative mode to CT-DNA with Kb value of 1.25 × 104 M-1. Furthermore, cleavage studies reveal that the complex has potential for efficient DNA cleavage under both oxidative and hydrolytic conditions. It was able to enhance the rate of cleavage by 2.8 × 108 times. The complex shows good cytotoxicity to breast cancer monolayer (2D) as well as spheroid (3D) systems. The IC50 values for MDA-MB-231 and MCF-7 monolayer culture was calculated as 1.86 ± 0.17 μM and 2.22 ± 0.08 μM, respectively, and in (3D) spheroids of MDA-MB-231 cells, the IC50 value was calculated to be 1.51 ± 0.29 μM. It was observed that the complex outperformed cisplatin in both breast cancer cell lines. The cells treated with complex 1 underwent severe DNA damage, increased oxidative stress and cell cycle arrest which finally led to programmed cell death or apoptosis in triple negative breast cancer cells through an intrinsic pathway.

Synthesis and antitumor activity of copper(II) complexes of imidazole derivatives

Complexes [Cu(PI)2(H2O)](NO3)2 (1), [Cu(PBI)2(NO3)]NO3 (2), [Cu(TBI)2(NO3)]NO3 (3), [Cu(BBIP)2](ClO4)2 (4) and [Cu(BBIP)(CH3OH)(ClO4)2] (5) were synthesized from the reactions of Cu(II) salts with 2-(2'-pyridyl)imidazole (PI), (2-(2'-pyridyl)benzimidazole (PBI), 2-(4'-thiazolyl)-benzimidazole (TBI), 2,6-bis(benzimidazol-2-yl)-pyridine (BBIP), respectively. Their compositions and crystal structures were determined. Their in-vitro antitumor activities were screened on four cancer cell lines and one normal cell line (HL-7702) using cisplatin as the positive control. Complexes 2 and 4 show higher cytotoxicity than the other three complexes. The cytotoxicity of complex 2 are comparable to those for cisplatin, and the cytotoxicity for 4 are much higher than those for cisplatin. From a viewpoint of antitumor, 2 might be a nice choice on the tumor cell line of T24 because its IC50 values on T24 and HL-7702 are 15.03 ± 1.10 and 21.34 ± 0.35, respectively. Thus, a mechanistic study for complexes 2 and 4 on T24 cells was conducted. It revealed that they can reduce mitochondrial membrane potential and increase mitochondrial membrane permeability, resulting in increased intracellular ROS levels, Ca2+ inward flow, dysfunctional mitochondria and the eventual cell apoptosis. In conclusion, they can induce cell apoptosis through mitochondrial dysfunction. These findings could be useful in the development of new antitumor agents.

Experimental and molecular modelling demonstration of effective DNA and protein binding as well as anticancer potential of two mononuclear Cu(II) and Co(II) complexes with isothiocyanate and azide as anionic residues

In the present study, one mononuclear Cu(II) [CuL(SCN)] (1) and one mononuclear Co(II) [CoLN3] (2) complexes, with a Schiff base ligand (HL) formed by condensation of 2-picolylamine and salicylaldehyde, have been successfully developed and structurally characterized. The square planer geometry of both complexes is fulfilled by the coordination of one deprotonated ligand and one ancillary ligand SCN-(1) or N3-(2) to the metal centre. Binding affinities of both complexes with deoxyribonucleic acid (DNA) and human serum albumin (HSA) are investigated using several biophysical and spectroscopic techniques. High values of the macromolecule-complex binding constants and other results confirm the effectiveness of both complexes towards binding with DNA and HSA. The determined values of the thermodynamic parameters support spontaneous interactions of both complexes with HSA, while fluorescence displacement and DNA melting studies establish groove-binding interactions with DNA for both complexes 1 and 2. The molecular modelling study validates the experimental findings. Both complexes are subjected to an MTT test establishing the anticancer property of complex 1 with lower risk to normal cells, confirmed by the IC50 values of the complex for HeLa cancer cells and HEK normal cells. Finally, a nuclear staining analysis reveals that the complexes have caused apoptotic cell death.

Development of Cu(II) 4-hydroxybenzoylhydrazone complexes that induce mitochondrial DNA damage and mitochondria-mediated apoptosis in liver cancer

Cisplatin remains the most widely used chemotherapeutic agent in cancer treatment; however, its inherent drawbacks have fueled the development of novel metalloanticancer drugs. In this study, two novel Cu(II) complexes (Cu1 and Cu2) were designed and synthesized. Notably, these Cu(II) complexes showed higher cytotoxicity against HL-7402 cells than cisplatin. Moreover, Cu(II) complexes significantly inhibited liver cancer growth in a xenograft model. A mechanism study revealed that the Cu(II) complexes reduced the mitochondrial membrane potential of cancer cells, produced excessive reactive oxygen species (ROS), induced mitochondrial DNA (mtDNA) damage, and ultimately facilitated cancer cell apoptosis.

Assessment of Mononuclear/Dinuclear copper acylhydrazone complexes for lung cancer treatment

Non-platinum metal-based complexes have good potential for cancer treatment. Here, we designed and synthesized five hydrazone copper(II) complexes, [Cu2(HL)2Cl2] 1A, [Cu2(HL)2(NO3)H2O]·NO3 2A, [Cu2(HL)2Br2] 3A, [Cu(L)pyridine] 1B and [Cu(HL)(pyridine)Br] 3B, and evaluated their anti-lung cancer activities. MTT experiments revealed that these copper(II) complexes exhibit higher anticancer activity than cisplatin. Mechanism studies revealed that complex 3A induced G1 phase cell cycle arrest, and induced cell apoptosis via reactive oxygen species (ROS)-mediated mitochondrial dysfunction. Scratch wound healing assay was also performed, revealing that complex 3A have good anti-cell migration activity. Hemolysis assays showed good blood biocompatibility of complex 3A. Furthermore, complex 3A can significantly inhibit the proliferation of A549 3D tumor spheroid. An in vivo anticancer study showed that complex 3A could delays the growth of A549 tumor xenografts with lower systemic toxicity. These results highlight the great possibility of developing highly active copper complexes as anti-lung cancer agents.

Recent Development on Copper-Sensor and its Biological Applications: A Review

Metal ion recognition is one of the most prospective research topics in the field of chemical sensors due to its wide range of clinical, biological and environmental applications. In this context, hydrazones are well known compounds that exhibit metal sensing and several biological properties due to the presence of N=CH- bond. Some of the biological properties includes anti-cancer, anti-tumor, anti-oxidant, anti-microbial activities. Hydrazones are also used as a ligand to detect metal ion as well as to generate metal complexes that exhibit medicinal properties. Thus, in recent years, many attempts were made to develop novel ligands with enhanced metal sensing and medicinal properties. In this review, some of the recent development on the hydrazones and their copper complexes are covered from the last few years from 2015-2023. These includes significance of copper ions, synthesis, biological properties, mechanism and metal sensing properties of some of the copper complexes were discussed.

Celastrol Alleviates Mitochondrial Oxidative Stress and Brain Injury After Intracerebral Hemorrhage by Promoting OPA1-Dependent Mitochondrial Fusion

Mitochondrial oxidative stress is one of the characteristics of secondary brain injury (SBI) after intracerebral hemorrhage (ICH), contributing largely to the apoptosis of neurons. Celastrol, a quinone methide triterpene that possesses antioxidant and mitochondrial protective properties, has emerged as a neuroprotective agent. However, the activity of celastrol has not been tested in ICH-induced SBI. In this study, we found that celastrol could effectively alleviate neurological function deficits and reduce brain oedema and neuronal apoptosis caused by ICH. Through electron microscopy, we found that celastrol could significantly attenuate mitochondrial morphology impairment. Therefore, we tested the regulatory proteins of mitochondrial dynamics and found that celastrol could reverse the downwards trend of OPA1 expression after ICH. In view of this, by culturing OPA1-deficient primary neurons and constructing neuron-specific OPA1 conditional knockout mice, we found that the protective effects of celastrol on mitochondrial morphology and function after ICH were counteracted in the absence of OPA1. Further experiments also showed that OPA1 is indispensable for the protective effects of celastrol on ICH-induced secondary brain injury. In summary, we have demonstrated that celastrol is a potential drug for the treatment of ICH and have revealed a novel mechanism by which celastrol exerts its antioxidant effects by promoting OPA1-mediated mitochondrial fusion.

The Schiff base hydrazine copper(II) complexes induce apoptosis by P53 overexpression and prevent cell migration through protease-independent pathways

Although chemotherapy has increased the life expectancy of cancer patients, its toxic side effects remain a major challenge. Recently, organometallic compounds, such as Schiff base copper complexes, have become promising candidates for next-generation anticancer drugs owing to their unique anticancer activities. In this study, binuclear copper(II) complex-1 and mononuclear copper(II) complex-2 were examined to analyze their anticancer mechanisms further. For this purpose, a viability test, flow cytometry analysis of apoptosis and the cell cycle, migration assay, and gene expression analysis were performed. According to our results, complex-1 was more cytotoxic than complex-2 at 24/48-h intervals. Our findings also demonstrated that both complexes induced apoptosis at IC50 concentrations and arrested the cell cycle at the G1-S checkpoint. However, complex-1 accelerates cell cycle arrest at the sub-G0/G1 phase more than complex-2 does. Furthermore, gene expression analysis showed that only complex-1 induces the expression of p53. Interestingly, both complexes induced Bcl-2 overexpression. However, they did not affect MMP-13 expression. More interestingly, both complexes inhibited cell migration in different ways, including amoeboid and collective, by recruiting protease-independent pathways. This study confirmed that adding several metal cores and co-ligands increased the activity of the complex. It also appeared that Cu-containing complexes could prevent the migration of cancer cells through protease-independent pathways, which can be used for novel therapeutic purposes.

Disparities in Cisplatin-Induced Cytotoxicity-A Meta-Analysis of Selected Cancer Cell Lines

Cisplatin is a classic anticancer drug widely used as a reference drug to test new metal complex drug candidates. We found an unexpected diversity in cisplatin-related cytotoxicity values, expressed as IC50 (the half-maximal inhibitory concentration) in tumour cell lines, such as MCF-7, HepG2 and HeLa. We reviewed the data published from 2018 to 2022. A total of 41 articles based on 56 in vitro experiments met our eligibility criteria. Using a meta-analysis based on a random effect model, we evaluated the cytotoxicity of cisplatin (IC50) after 48- or 72-h cell exposure. We found large differences between studies using a particular cell line. According to the random effect model, the 95% confidence intervals for IC50 were extremely wide. The heterogeneity of cisplatin IC50, as measured by the I2 index for all cancer cell lines, was over 99.7% at culture times of 48 or 72 h. Therefore, the variability between studies is due to experimental heterogeneity rather than chance. Despite the higher IC50 values after 48 h than after 72 h, the heterogeneity between the two culture periods did not differ significantly. This indicates that the duration of cultivation is not the main cause of heterogeneity. Therefore, the available data is diverse and not useful as a reference. We discuss possible reasons for the IC50 heterogeneity and advise researchers to conduct preliminary testing before starting experiments and not to solely rely on the published data. We hope that this systematic meta-analysis will provide valuable information for researchers searching for new cancer drugs using cisplatin as a reference drug.

Synthesis and anticancer mechanisms of zinc(II)-8-hydroxyquinoline complexes with 1,10-phenanthroline ancillary ligands

Twenty new zinc(II) complexes with 8-hydroxyquinoline (H-Q1-H-Q6) in the presence of 1,10-phenanthroline derivatives (D1-D10) were synthesized and formulated as [Zn(Q1)₂(D1)] (DQ1), [Zn(Q2)₂(D2)]·CH₃OH (DQ2), [Zn(Q1)₂(D3)] (DQ3), [Zn(Q1)₂(D4)] (DQ4), [Zn(Q3)₂(D5)] (DQ5), [Zn(Q3)₂(D4)] (DQ6), [Zn(Q4)₂(D5)]·CH₃OH (DQ7), [Zn(Q4)₂(D6)] (DQ8), [Zn(Q4)₂(D3)]·CH₃OH (DQ9), [Zn(Q4)₂(D1)]·H₂O (DQ10), [Zn(Q5)₂(D4)] (DQ11), [Zn(Q6)₂(D6)]·CH₃OH (DQ12), [Zn(Q5)₂(D2)]·5CH₃OH·H₂O (DQ13), [Zn(Q5)₂(D7)]·CH₃OH (DQ14), [Zn(Q5)₂(D8)]·CH₂Cl₂ (DQ15), [Zn(Q5)₂(D9)] (DQ16), [Zn(Q5)₂(D1)] (DQ17), [Zn(Q5)₂(D5)] (DQ18), [Zn(Q5)₂(D10)]·CH₂Cl₂ (DQ19) and [Zn(Q5)₂(D3)] (DQ20). They were characterized using multiple techniques. The cytotoxicity of DQ1-DQ20 was screened using human cisplatin-resistant SK-OV-3/DDP ovarian cancer (SK-OV-3CR) cells and normal hepatocyte (HL-7702) cells. Complex DQ6 showed low IC₅₀ values (2.25 ± 0.13 μM) on SK-OV-3CR cells, more than 3.0-8.0 times more cytotoxic than DQ1-DQ5 and DQ7-DQ20 (≥6.78 μM), and even 22.2 times more cytotoxic than the standard cisplatin, the corresponding free H-Q1-H-Q6 and D1-D10 alone (>50 μM). As a comparison, DQ1-DQ20 displayed nontoxic rates against healthy HL-7702 cells. Furthermore, DQ6 and DQ11 induced significant apoptosis via mitophagy pathways. DQ6 also significantly inhibited tumor growth in an in vivo SK-OV-3-xenograft model (ca. 49.7%). Thus, DQ6 may serve as a lead complex for the discovery of new antitumor agents.

A novel prognostic scoring model based on copper homeostasis and cuproptosis which indicates changes in tumor microenvironment and affects treatment response

Background: Intracellular copper homeostasis requires a complex system. It has shown considerable prospects for intervening in the tumor microenvironment (TME) by regulating copper homeostasis and provoking cuproptosis. Their relationship with hepatocellular carcinoma (HCC) remains elusive. Methods: In TCGA and ICGC datasets, LASSO and multivariate Cox regression were applied to obtain the signature on the basis of genes associated with copper homeostasis and cuproptosis. Bioinformatic tools were utilized to reveal if the signature was correlated with HCC characteristics. Single-cell RNA sequencing data analysis identified differences in tumor and T cells' pathway activity and intercellular communication of immune-related cells. Real-time qPCR analysis was conducted to measure the genes' expression in HCC and adjacent normal tissue from 21 patients. CCK8 assay, scratch assay, transwell, and colony formation were conducted to reveal the effect of genes on in vitro cell proliferation, invasion, migration, and colony formation. Results: We constructed a five-gene scoring system in relation to copper homeostasis and cuproptosis. The high-risk score indicated poor clinical prognosis, enhanced tumor malignancy, and immune-suppressive tumor microenvironment. The T cell activity was markedly reduced in high-risk single-cell samples. The high-risk HCC patients had a better expectation of ICB response and reactivity to anti-PD-1 therapy. A total of 156 drugs were identified as potential signature-related drugs for HCC treatment, and most were sensitive to high-risk patients. Novel ligand-receptor pairs such as FASLG, CCL, CD40, IL2, and IFN-Ⅱ signaling pathways were revealed as cellular communication bridges, which may cause differences in TME and immune function. All crucial genes were differentially expressed between HCC and paired adjacent normal tissue. Model-constructed genes affected the phosphorylation of mTOR and AKT in both Huh7 and Hep3B cells. Knockdown of ZCRB1 impaired the proliferation, invasion, migration, and colony formation in HCC cell lines. Conclusion: We obtained a prognostic scoring system to forecast the TME changes and assist in choosing therapy strategies for HCC patients. In this study, we combined copper homeostasis and cuproptosis to show the overall potential risk of copper-related biological processes in HCC for the first time.

Thiosemicarbazone N-Heterocyclic Cu(II) complexes inducing nuclei DNA and mitochondria damage in hepatocellular carcinoma cells

The α-N-Heterocyclic thiosemicarbazones and their metal complexes have been widely investigated as anticancer and antibacterial agents for their broad spectrum of pharmacological properties. Thus, two thiosemicarbazone-based Cu(II) complexes, [Cu₂(ptpc)I₂] (1) and [Cu(qtpc)I] (2) with thiosemicarbazone ligand (ptpc = 2-(di(pyridin-2-yl)methylene)-N-(2-(trifluoromethyl)phenyl)-hydrazine-1-carbothioamide, qtpc = 2-(quinolin-8-ylmethylene)-N-(2-(trifluoromethyl)phenyl)hydrazine-1-carbothioamide) were synthesized and evaluated for their biological activities. Complexes 1 and 2 are superior to cisplatin in vitro antiproliferative activities toward hepatocellular carcinoma cell line with the half maximal inhibitory concentration value of 0.2 and 2 μM, respectively. A series of spectroscopic assays and the DNA cleavage experiments showed that both complexes can change and distort the conformation of DNA. Molecular docking experiment further demonstrated that complex 1 binds to DNA mainly in groove mode. Meanwhile, benefiting from their good liposolubility, complexes 1 and 2 could easily enter cells, which further triggers cell cycle arrest and apoptosis. Moreover, complexes 1 and 2 caused serious mitochondrial damage, associating with increased the level of reactive oxygen species (ROS) and Ca²⁺, decreased adenosine triphosphate (ATP) content and mitochondrial membrane potential (Δψ_m), and transformed mitochondrial morphology. These findings indicated that complexes 1 and 2 might exert their anticancer activity by inducing DNA and mitochondrial damage simultaneously.

Evaluation of In Vitro Cytotoxic, Genotoxic, Apoptotic, and Cell Cycle Arrest Potential of Iron-Nickel Alloy Nanoparticles

The use of iron-nickel alloy nanoparticles (Fe-Ni ANPs) is increasing daily in various fields. People are increasingly exposed to these nanoparticles for occupational and environmental reasons. Our study determined some of the effects of Fe-Ni ANP exposure and impacts on human health at the cellular level. The cytotoxic and genotoxic potentials of Fe-Ni ANPs were investigated by XTT, clonogenic, comet, and GammaH2AX analyses using Beas-2B cells. Annexin V, multicaspase, and cell cycle arrest methods were used to understand the apoptotic mechanism of action. The intracellular ROS method was used to determine the primary mechanism that leads to cytotoxic and genotoxic activity. The Fe-Ni ANPs showed cytotoxic activity with the XTT and clonogenic methods: they had genotoxic potential, as demonstrated via genotoxicity methods. It was determined that the cytotoxic effect was realized by the caspase-dependent apoptotic pathway, and the cells were stopped at the G0/G1 stage by Fe-Ni ANPs. Increased intracellular ROS due to Fe-Ni ANPs led to cytotoxic, genotoxic, and apoptotic activity. Potential risks to human health due to Fe-Ni ANPs were then demonstrated at the cellular level.

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.

Terpyridine copper(II) complexes as potential anticancer agents by inhibiting cell proliferation, blocking the cell cycle and inducing apoptosis in BEL-7402 cells

Four mononuclear terpyridine complexes [Cu(H-L^a)Cl₂]·CH₃OH (1), [Cu(H-L^a)Cl]ClO₄ (2), [Cu(H-L^b)Cl₂]·CH₃OH (3), and [Cu(H-L^b)(CH₃OH)(DMSO)](ClO₄)₂ (4) were prepared and fully characterized. Complexes 1-4 exhibited higher cytotoxic activity against several tested cancer cell lines especially BEL-7402 cells compared to cisplatin, and they showed low toxicity towards normal human liver cells. ICP-MS detection indicated that the copper complexes were accumulated in mitochondria. Mechanistic studies demonstrated that the copper complexes induced G0/G1 arrest and altered the expression of the related proteins of the cell cycle. All copper complexes reduced the mitochondrial membrane potential while increasing the intracellular ROS levels and the release of Ca²⁺. They also up-regulated Bax and down-regulated Bcl-2 expression levels, caused cytochrome c release and the activation of the caspase cascade, and induced mitochondrion-mediated apoptosis. Animal studies demonstrated that complex 1 suppressed tumor growth in a mouse xenograft model bearing BEL-7402 tumor cells.

Evaluation of antitumor potential of Cu(II) complex with hydrazone of 2-acetylthiazole and Girard’s t reagent

In this paper, the previously synthesized Cu(II) complex ([CuL1(N3) (CH3OH)]BF4) with N,N,N-trimethyl-2-oxo-2-(2-(1-(thiazol-2-yl)ethylidene)- hydrazinyl)ethan-1-aminium chloride, has been characterized and its biological activity has been studied in detail. The Cu(II) complex consists of ligand coordinated in a deprotonated, formally neutral zwitter-ionic form, via NNO atoms, one azido ligand and one methanol molecule. The Cu(II) complex was selected due to results of the cytotoxic activity, the brine shrimp test and DPPH radical scavenging activity, which were previously performed. The effects of Cu(II) complex on cell cycle phase distribution of cervical adenocarcinoma HeLa cells were investigated in order to examine the mechanisms of its anticancer activity. The measurement of intracellular ROS levels in HeLa and HaCaT cell lines were evaluated in order to explore their possible generation and the role in cytotoxic activity. The possible anti-invasive and anti-angiogenic properties of Cu(II) complex were evaluated. DNA binding experiments, including fluorescence displacement study and DNA cleavage experiments, were performed in order to obtain information on the type of DNA-metal complex interactions.

Dithiocarbazate-copper complex loaded thermosensitive hydrogel for lung cancer therapy via tumor in situ sustained-release

The Pluronic F127 thermosensitive hydrogels containing copper complex 3 were constructed, which could delay A549 tumor xenograft growth effectively with lower systemic toxicity.

Synthesis, structural studies, interaction with DNA/HSA and antitumor evaluation of new Cu(ii) complexes containing 2-(1H-imidazol-2-yl)pyridine and amino acids

New Cu(ii) complexes with promising anticancer activity induce apoptosis in HepG2 cells through DNA damage and cytotoxic ROS-mediated mitochondrial dysfunction pathways.

Evaluation of anticancer activity in vitro of a stable copper(I) complex with phosphine-peptide conjugate

[CuI(2,9-dimethyl-1,10-phenanthroline)P(p-OCH₃-Ph)₂CH₂SarcosineGlycine] (1-MPSG), highly stable in physiological media phosphino copper(I) complex—is proposed herein as a viable alternative to anticancer platinum-based drugs. It is noteworthy that, 1-MPSG significantly and selectively reduced cell viability in a 3D spheroidal model of human lung adenocarcinoma (A549), in comparison with non-cancerous HaCaT cells. Confocal microscopy and an ICP-MS analysis showed that 1-MPSG effectively accumulates inside A549 cells with colocalization in mitochondria and nuclei. A precise cytometric analysis revealed a predominance of apoptosis over the other types of cell death. In the case of HaCaT cells, the overall cytotoxicity was significantly lower, indicating the selective activity of 1-MPSG towards cancer cells. Apoptosis also manifested itself in a decrease in mitochondrial membrane potential along with the activation of caspases-3/9. Moreover, the caspase inhibitor (Z-VAD-FMK) pretreatment led to decreased level of apoptosis (more pronouncedly in A549 cells than in non-cancerous HaCaT cells) and further validated the caspases dependence in 1-MPSG-induced apoptosis. Furthermore, the 1-MPSG complex presumably induces the changes in the cell cycle leading to G2/M phase arrest in a dose-dependent manner. It was also observed that the 1-MPSG mediated intracellular ROS alterations in A549 and HaCaT cells. These results, proved by fluorescence spectroscopy, and flow cytometry, suggest that investigated Cu(I) compound may trigger apoptosis also through ROS generation.

Copper in tumors and the use of copper-based compounds in cancer treatment

Copper homeostasis is strictly regulated by protein transporters and chaperones, to allow its correct distribution and avoid uncontrolled redox reactions. Several studies address copper as involved in cancer development and spreading (epithelial to mesenchymal transition, angiogenesis). However, being endogenous and displaying a tremendous potential to generate free radicals, copper is a perfect candidate, once opportunely complexed, to be used as a drug in cancer therapy with low adverse effects. Copper ions can be modulated by the organic counterpart, after complexed to their metalcore, either in redox potential or geometry and consequently reactivity. During the last four decades, many copper complexes were studied regarding their reactivity toward cancer cells, and many of them could be a drug choice for phase II and III in cancer therapy. Also, there is promising evidence of using ⁶⁴Cu in nanoparticles as radiopharmaceuticals for both positron emission tomography (PET) imaging and treatment of hypoxic tumors. However, few compounds have gone beyond testing in animal models, and none of them got the status of a drug for cancer chemotherapy. The main challenge is their solubility in physiological buffers and their different and non-predictable mechanism of action. Moreover, it is difficult to rationalize a structure-based activity for drug design and delivery. In this review, we describe the role of copper in cancer, the effects of copper-complexes on tumor cell death mechanisms, and point to the new copper complexes applicable as drugs, suggesting that they may represent at least one component of a multi-action combination in cancer therapy.

Synthesis, DNA binding, antibacterial and anticancer properties of two novel water-soluble copper(II) complexes containing gluconate

In this paper, two new Cu(II) complexes, [Cu(Gluc)(HPB)(H₂O)]Gluc (CuG1) and [Cu(Gluc)(HPBC)(H₂O)]Gluc (CuG2) (where HPB = 2-(2'-pyridyl)benzimidazole, HPBC = 5-chloro-2-(2'-pyridyl)benzimidazole, Gluc = d-Gluconic acid), with good water solubility were synthesized and characterized. These complexes exhibited a five-coordinated tetragonal pyramidal geometry. The DNA binding and cleavage properties of the complexes were investigated using multi-spectroscopy, viscosity measurement, molecular docking and gel electrophoresis analysis methods. The results showed that the complexes could interact with DNA by insertion and groove binding, and cleave CT-DNA through a singlet oxygen-dependent pathway in the presence of ascorbic acid. The studies on antibacterial and anticancer activities in vitro demonstrated that both complexes had good inhibitory activity against three Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis, Listeria monocytogenes) and one Gram-negative bacterium (Escherichia coli) and good cytotoxic activity toward the tested cancer cells (A549, HeLa and SGC-7901). CuG2 showed higher antimicrobial and cytotoxic activities than CuG1, which was consistent with their binding strength and cleavage ability to DNA, indicating that their antimicrobial and cytotoxic activities may be related to the DNA interaction. Moreover, the cell-based mechanism studies have indicated that CuG1 and CuG2 could arrest the cell cycle at G2/M phase, elevate the levels of intracellular reactive oxygen species (ROS) and decrease the mitochondrial membrane potential (MMP). The results showed that the complexes could induce apoptosis through DNA-damaged and ROS-mediated mitochondrial dysfunction pathways. Finally, the in vivo antitumor study revealed that CuG2 inhibited tumor growth by 50.44%, which is better than that of cisplatin (40.94%).

Mononuclear Perfluoroalkyl-Heterocyclic Complexes of Pd(II): Synthesis, Structural Characterization and Antimicrobial Activity

Two mononuclear Pd(II) complexes [PdCl₂(pfptp)] (1) and [PdCl₂(pfhtp)] (2), with ligands 2-(3-perfluoropropyl-1-methyl-1,2,4-triazole-5yl)-pyridine (pfptp) and 2-(3-perfluoroheptyl-1-methyl-1,2,4-triazole-5yl)-pyridine (pfhtp), were synthesized and structurally characterized. The two complexes showed a bidentate coordination of the ligand occurring through N atom of pyridine ring and N4 atom of 1,2,4-triazole. Both complexes showed antimicrobial activity when tested against both Gram-negative and Gram-positive bacterial strains.

On the Hirshfeld surface for copper(II) atoms in different coordination environments

Copper(II) chemistry has always attracted interest owing to its rich coordination geometry. On the one hand, the variety of geometries that the copper(II) atom can adopt makes it a versatile metal with high applicability. On the other hand, the difficulties in controlling the copper(II) geometry may hinder its use in the design of molecules. To evaluate the use of Hirshfeld surfaces for obtaining information related to coordination geometry in copper(II) compounds, the behaviour of the surfaces generated for the copper(II) centres in different coordination environments is analysed. Structural details of four compounds were retrieved from the Cambridge Structural Database and analysed along with the crystal structure of a new compound, namely chloro-bis(1,10-phenanthroline)copper(II) 2-carboxy-4-nitrobenzoate 4-nitrophthalic acid dihydrate {[CuCl(C12H8N2)2]+(C8H4NO6)−·C8H5NO6·2H2O}, here described. The obtained Hirshfeld surfaces behave differently according to the coordination environment, presenting different shapes and shape-related parameters. Furthermore, the curvature properties and fingerprint plots can be useful for evaluating the differences that might occur in the coordination environment.

Tracking the dissolution-recrystallization structural transformation (DRST) of copper(II) complexes: a combined crystallographic, mass spectrometric and DFT study

Methanol- and temperature-induced dissolution-recrystallization structural transformation (DRST) was observed among two novel Cu^II complexes. This is first time that the combination of X-ray crystallography, mass spectrometry and density functional theory (DFT) theoretical calculations has been used to describe the fragmentation and recombination of a mononuclear Cu^II complex at 60 °C in methanol to obtain a binuclear copper(II) complex. Combining time-dependent high-resolution electrospray mass spectrometry, we propose a possible mechanism for the conversion of bis(8-methoxyquinoline-κ²N,O)bis(thiocyanato-κN)copper(II), [Cu(NCS)₂(C₁₀H₉NO)₂], Cu1, to di-μ-methanolato-κ⁴O:O-bis[(8-methoxyquinoline-κ²N,O)(thiocyanato-κN)copper(II)], [Cu₂(CH₃O)₂(NCS)₂(C₁₀H₉NO)₂], Cu2, viz. [Cu(SCN)₂(L)₂] (Cu1) → [Cu(L)₂] → [Cu(L)]/L → [Cu₂(CH₃O)₂(NCS)₂(L)₂] (Cu2). We screened the antitumour activities of L (8-methoxyquinoline), Cu1 and Cu2 and found that the antiproliferative effect of Cu2 on some tumour cells was much greater than that of L and Cu1.

Copper Coordination Compounds as Biologically Active Agents

Copper-containing coordination compounds attract wide attention due to the redox activity and biogenicity of copper ions, providing multiple pathways of biological activity. The pharmacological properties of metal complexes can be fine-tuned by varying the nature of the ligand and donor atoms. Copper-containing coordination compounds are effective antitumor agents, constituting a less expensive and safer alternative to classical platinum-containing chemotherapy, and are also effective as antimicrobial, antituberculosis, antimalarial, antifugal, and anti-inflammatory drugs. 64Сu-labeled coordination compounds are promising PET imaging agents for diagnosing malignant pathologies, including head and neck cancer, as well as the hallmark of Alzheimer's disease amyloid-β (Aβ). In this review article, we summarize different strategies for possible use of coordination compounds in the treatment and diagnosis of various diseases, and also various studies of the mechanisms of antitumor and antimicrobial action.

Isoxazole-Derived Aroylhydrazones and Their Dinuclear Copper(II) Complexes Show Antiproliferative Activity on Breast Cancer Cells with a Potentially Alternative Mechanism Of Action

This paper reports the design, synthesis and cytotoxicity studies of two new isoxazole-derived aroylhydrazone ligands and their dinuclear copper(II) complexes. Compounds were fully characterized by various spectroscopic and analytical techniques. The molecular structures of four derivatives were confirmed by X-ray crystallography. The stability of the ligands and the complexes in aqueous medium was monitored spectroscopically. Both the ligands and the complexes were shown to interact with calf thymus DNA (ct-DNA). Additionally, structures containing a phenol pendant arm were significantly more cytotoxic than those carrying a pendant pyridine substituent, reaching sub-micromolar IC₅₀ values on the triple-negative human breast cancer cell line MDA-MB-231. The metal chelation and transchelation ability of the compounds towards Fe^II , Fe^III and Zn^II ions was explored as a possible mechanism of action of these compounds.

Anticancer activity studies of novel metal complexes of ligands derived from polycyclic aromatic compound via greener route

Methoxy and tert-butyl substituted carboxamide, carboxylic acid and hydrazone Schiff base groups have been assembled into our newly designed fluorenone based ligands and prepared coordination compounds of some first row transition metals and characterized thoroughly with spectroscopic (1H and 13C NMR, IR, GC-MS, UV-Vis), analytical, TGA and molar conductance measurements. The stoichiometry of all the metal complexes is found to be 1: 2 (M: L2) with the general formula, [M(L)2], where L is a singly deprotonated ligand and the geometry of all the metal complexes is found to be octahedral. Ligands and their metal complexes successfully cleaved the pBR322 plasmid DNA and in case of anticancer activity against MCF-7 (human breast adenocarcinoma) cell line, the synthesized compounds found to exhibit excellent activity with prominent apoptotic effect which is characterized by cell shrinkage, cell breakage and turgidity and results were compared with the standard drug cisplatin. Very significant anticancer activity was observed for compounds L1H, Cu(L1)2, Cu(L2)2, Ni(L1)2 and Ni(L2)2 with IC50 value of <10 μgmL-1. Molecular docking studies were performed to assess the bonding mode of synthesized compounds. In case of antioxidant activity study, the compounds L1H, Ni(L1)2, Ni(L2)2, Cu(L1)2 and Cu(L2)2 exhibited significant scavenging activity with good percentage when compared with remaining tested compounds.

Zinc and Copper with New Triazine Hydrazone Ligand: Two Novel Organic Complexes Enhanced Expression of Peptide Growth Factors and Cytokine Genes in Weaned V-Line Rabbit

Simple Summary

Zinc and Copper are two important trace minerals, which are involved in numerous vital biological activities in animal’s body, such as enzyme activation and enhancement of immune function, growth, reproduction, DNA synthesis, cell division, and neurotransmitters production. Recently, the application of trace mineral organic complexes in animal feed received much more attention than the inorganic sources. The organic sources can contribute significantly to improving animals’ health and reproduction, as the minerals are more biologically available and absorbable than they are when coming from the inorganic sources. In this study, three injectable varieties of Zn and Cu supplementation, sulfate, inorganic (loaded with montmorillonite), and novel organic (ligand with triazine hydrazone), were tested with weaned rabbits. The results revealed that these three mineral types vary at the most biological responses, and only one category of our novel organic complexes provided consistent animal performance improvement, including weight gain, serum antioxidant, meat quality, intestine morphometry, and the expression of peptide growth factors and cytokine genes. To our knowledge, this is the first work on the Zn and Cu with triazine hydrazone ligand as two organic complexes in rabbits.

Abstract

Two novel transitional organic Zn/Cu complexes based on a new biocompatible bidentate triazine–hydrazone ligand (Thz) was designed, synthesized, and evaluated in this study. This study evaluated the effects of injecting 60 mg of Zn and 40 mg of Cu in three different forms, twice per week, for eight weeks on growth performance, expression of growth factors and cytokine genes, carcass yield, blood biochemicals, and intestinal morphology in weaned rabbits. The tested complexes were sulfate (Cu/ZnSO₄), montmorillonite (Cu/Zn-Mnt), and triazine hydrazone (Cu/Zn-Thz). A total of 60 V-line weaned rabbits at four weeks of age were assigned to four treatments (n = 15), which were intramuscularly injected with 0.5 mL of either (1) saline (control) or saline containing (2) Cu/ZnSO₄, (3) Cu/Zn-Mnt, or (4) Cu/Zn-Thz. Compared to the controls, the rabbits injected with Cu/Zn-Thz showed a higher (p < 0.01) growth rate, carcass yield (p < 0.05), and liver expression of insulin like growth factor-1 (IGF-1), growth hormone receptor (GHR), fibroblast growth factor-1 (FGF1), and transforming growth factor beta-1 (TGFB1) (p < 0.05), as well as better jejunum morphometric variables (p < 0.05). On the other hand, mRNA of FGF1, TGF1, TCIRG1, and adenosine deaminase (ADA) were higher expressed (p < 0.05) in the spleen tissues of Cu/Zn-Mnt group. Collectively, the results indicated that our novel synthesized organic complexes of Zn/Cu-Thz proved to be a suitable feed supplement, as it increased rabbit productive performance through enhancing expression of peptide growth factors and cytokine genes.

Anticancer and biological properties of a Zn-2,6-diacetylpyridine bis(thiosemicarbazone) complex

Herein, to develop a multi-target anticancer metal agent and achieve a "1 + 1 > 2" pharmaceutical effect, we rationally designed and synthesized five complexes (C1-C5) by synergistically exploiting the properties of Zn(ii) and a series of modified 2,6-diacetylpyridine bis(thiosemicarbazone) ligands. By investigating the structure-activity relationships, we found that the binuclear Zn(ii) complex (C5) acts against human bladder cancer cells (T-24) with significant cytotoxicity. We subsequently determined the multiple anticancer mechanisms of C5 to T-24 cells, including inhibiting the activity of topoisomerase I (Topo I), blocking the cell cycle in the S phase, and inducing apoptosis and autophagy in T-24 cells. Furthermore, C5 inhibited the migration of T-24 cells and showed a significant cytostatic effect in the T-24 3D spheroid model.