A novel copper(II) complex identified as a potent drug against colorectal and breast cancer cells and as a poison inhibitor for human topoisomerase IIα

Enhancement of antitumor effects of berberine chloride with a copper(II) complex against human triple negative breast cancer: In vitro studies

In this study, the copper(II) complex [Cu(chromoneTSC)Cl2]•0.5H2O•0.0625C2H5OH (where chromoneTSC = (E)-N-Ethyl-2-((4-oxo-4H-chromen-3-yl)methylene)-hydrazinecarbothioamide) was synthesized and characterized; then used to carry out in vitro studies in combination with berberine chloride (BBC). The ligand and complex were characterized by elemental analysis, FTIR and NMR (1H and 13C) spectroscopy, and conductivity measurements. The cytotoxic effect was analyzed by using the CCK-8 viability assay in cancer MDA-MB-231 VIM RFP and non-cancer MCF-10A cell lines. The IC50 values for the complex and BBC were 21.2 ±1.6 and 48.3 ± 2.4 μM, respectively at 24 h incubation, while the IC50 value of the combination treatment was 9.3 ± 1.5 in cancer cells. The co-treatment group significantly increased the number of cells in G2 phase, indicating the growth arrest of cancer cells. Moreover, the combination group showed induction of both intrinsic and extrinsic apoptotic pathways. There was also a study on the effect of the combination treatment on receptor-interacting serine/threonine-protein kinase 3 (RIPK3) and mixed lineage kinase domain-like pseudokinase (MLKL) as biomarkers of necroptosis. The results showed activation of necroptosis after treatment with the combination of the copper complex and BBC via the activation of RIPK3-MLKL pathway.

Synergy of experimental and computational chemistry: structure and biological activity of Zn(II) hydrazone complexes

In this paper, three different Zn(II) complexes with (E)-2-(2-(1-(6-bromopyridin-2-yl)ethylidene)hydrazinyl)-N,N,N-trimethyl-2-oxoethan-1-aminium chloride (HLCl) have been synthesized and characterized by single crystal X-ray diffraction, elemental analysis, IR and NMR spectroscopy. All complexes are mononuclear, with the ligand (L) coordinated in a deprotonated formally neutral zwitterionic form via NNO donor set atoms. Complex 1 forms an octahedral geometry with the composition [ZnL2](BF4)2, while complexes 2 [ZnL(NCO)2] and 3 [ZnL(N3)2] form penta-coordinated geometry. Density functional theory (DFT) calculations were performed to enhance our understanding of the structures of the synthesized complexes and the cytotoxic activity of the complexes was tested against five human cancer cell lines (HeLa, A549, MDA-MB-231, K562, LS 174T) and normal human fibroblasts MRC-5. Additionally, antibacterial and antifungal activity of these complexes was tested against a panel of Gram-negative and Gram-positive bacteria, two fungal strains, and a yeast strain. It is noteworthy that all three complexes show selective antifungal activity comparable to that of amphotericin B. Molecular docking analysis predicted that geranylgeranyl pyrophosphate synthase, an enzyme essential for sterol biosynthesis, is the most likely target for inhibition by the tested complexes.

Copper in colorectal cancer: From copper-related mechanisms to clinical cancer therapies

Copper, a trace element and vital cofactor, plays a crucial role in the maintenance of biological functions. Recent evidence has established significant correlations between copper levels, cancer development and metastasis. The strong redox-active properties of copper offer both benefits and disadvantages to cancer cells. The intestinal tract, which is primarily responsible for copper uptake and regulation, may suffer from an imbalance in copper homeostasis. Colorectal cancer (CRC) is the most prevalent primary cancer of the intestinal tract and is an aggressive malignant disease with limited therapeutic options. Current research is primarily focused on the relationship between copper and CRC. Innovative concepts, such as cuproplasia and cuproptosis, are being explored to understand copper-related cellular proliferation and death. Cuproplasia is the regulation of cell proliferation that is mediated by both enzymatic and nonenzymatic copper-modulated activities. Whereas, cuproptosis refers to cell death induced by excess copper via promoting the abnormal oligomerisation of lipoylated proteins within the tricarboxylic acid cycle, as well as by diminishing the levels of iron-sulphur cluster proteins. A comprehensive understanding of copper-related cellular proliferation and death mechanisms offers new avenues for CRC treatment. In this review, we summarise the evolving molecular mechanisms, ranging from abnormal intracellular copper concentrations to the copper-related proteins that are being discovered, and discuss the role of copper in the pathogenesis, progression and potential therapies for CRC. Understanding the relationship between copper and CRC will help provide a comprehensive theoretical foundation for innovative treatment strategies in CRC management.

Copper Nanodrugs by Atom Transfer Radical Polymerization

In this study, some copper catalysts used for atom transfer radical polymerization (ATRP) were explored as efficient anti-tumor agents. The aqueous solution of copper-containing nanoparticles with uniform spheric morphology was in situ prepared through a copper-catalyzed activator generated by electron transfer (AGET) ATRP in water. Nanoparticles were then directly injected into tumor-bearing mice for antitumor chemotherapy. The copper nanodrugs had prolonged blood circulation time and enhanced accumulation at tumor sites, thus showing potent antitumor activity. This work provides a novel strategy for precise and large-scale preparation of copper nanodrugs with high antitumor activity.

A Comparison of In Vitro Studies between Cobalt(III) and Copper(II) Complexes with Thiosemicarbazone Ligands to Treat Triple Negative Breast Cancer

Metal complexes have gained significant attention as potential anti-cancer agents. The anti-cancer activity of [Co(phen)2(MeATSC)](NO3)3•1.5H2O•C2H5OH 1 (where phen = 1,10-phenanthroline and MeATSC = 9-anthraldehyde-N(4)-methylthiosemicarbazone) and [Cu(acetylethTSC)Cl]Cl•0.25C2H5OH 2 (where acetylethTSC = (E)-N-ethyl-2-[1-(thiazol-2-yl)ethylidene]hydrazinecarbothioamide) was investigated by analyzing DNA cleavage activity. The cytotoxic effect was analyzed using CCK-8 viability assay. The activities of caspase 3/7, 9, and 1, reactive oxygen species (ROS) production, cell cycle arrest, and mitochondrial function were further analyzed to study the cell death mechanisms. Complex 2 induced a significant increase in nicked DNA. The IC50 values of complex 1 were 17.59 μM and 61.26 μM in cancer and non-cancer cells, respectively. The IC50 values of complex 2 were 5.63 and 12.19 μM for cancer and non-cancer cells, respectively. Complex 1 induced an increase in ROS levels, mitochondrial dysfunction, and activated caspases 3/7, 9, and 1, which indicated the induction of intrinsic apoptotic pathway and pyroptosis. Complex 2 induced cell cycle arrest in the S phase, ROS generation, and caspase 3/7 activation. Thus, complex 1 induced cell death in the breast cancer cell line via activation of oxidative stress which induced apoptosis and pyroptosis while complex 2 induced cell cycle arrest through the induction of DNA cleavage.

Overview of the New Bioactive Heterocycles as Targeting Topoisomerase Inhibitors Useful Against Colon Cancer

Colorectal cancer (CRC) is the third most common cancer globally, with high mortality. Metastatic CRC is incurable in most cases, and multiple drug therapy can increase patients' life expectancy by 2 to 3 years. Efforts are being made to understand the relationship between topoisomerase enzymes and colorectal cancer. Some studies have shown that higher expression of these enzymes is correlated to a poor prognosis for this type of cancer. One of the primary drugs used in the treatment of CRC is Irinotecan, which can be used in monotherapy or, more commonly, in therapeutic schemes such as FOLFIRI (Fluorouracil, Leucovorin, and Irinotecan) and CAPIRI (Capecitabine and Irinotecan). Like Camptothecin, Irinotecan and other compounds have a mechanism of action based on the formation of a ternary complex with topoisomerase I and DNA providing damage to it, therefore leading to cell death. Thus, this review focused on the principal works published in the last ten years that demonstrate a correlation between the inhibition of different isoforms of topoisomerase and in vitro cytotoxic activity against CRC by natural products, semisynthetic and synthetic compounds of pyridine, quinoline, acridine, imidazoles, indoles, and metal complexes. The results revealed that natural compounds, semisynthetic and synthetic derivatives showed potential in vitro cytotoxicity against several colon cancer cell lines, and this activity was often accompanied by the ability to inhibit both isoforms of topoisomerase (I and II), highlighting that these enzymes can be promising targets for the development of new chemotherapy against CRC. Pyridine analogs were considered the most promising for this study, while the evaluation of the real potential of natural products was limited by the lack of information in their work. Moreover, the complexes, although promising, presented as the main limitation the lack of selectivity.

Ligand and Linkage Isomers of Bis(ethylthiocarbamato) Copper Complexes with Cyclic C6H8 Backbone Substituents: Synthesis, Characterization, and Antiproliferation Activity

A series of isomeric bis(alkylthiocarbamate) copper complexes have been synthesized, characterized, and evaluated for antiproliferation activity. The complexes were derived from ligand isomers with 3-methylpentyl (H2L2) and cyclohexyl (H2L3) backbone substituents, which each yield a pair of linkage isomers. The thermodynamic products CuL2a/3a have two imino N and two S donors resulting in three five-member chelate rings (555 isomers). The kinetic isomers CuL2b/3b have one imino and one hydrazino N donor and two S donors resulting in four-, six-, and five-member rings (465 isomers). The 555 isomers have more accessible CuII/I potentials (E1/2 = -811/-768 mV vs. ferrocenium/ferrocene) and lower energy charge transfer bands than their 465 counterparts (E1/2 = -923/-854 mV). Antiproliferation activities were evaluated against the lung adenocarcinoma cell line (A549) and nonmalignant lung fibroblast cell line (IMR-90) using the MTT assay. CuL2a was potent (A549EC50 = 0.080 μM) and selective (IMR-90EC50/A549EC50 = 25) for A549. Its linkage isomer CuL2b had equivalent A549 activity, but lower selectivity (IMR-90EC50/A549EC50 = 12.5). The isomers CuL3a and CuL3b were less potent with A549EC50 values of 1.9 and 0.19 μM and less selective with IMR-90EC50/A549EC50 ratios of 2.3 and 2.65, respectively. There was no correlation between reduction potential and A549 antiproliferation activity/selectivity.

Inhibition of Topoisomerases by Metal Thiosemicarbazone Complexes

Topoisomerases, common targets for anti-cancer therapeutics, are crucial enzymes for DNA replication, transcription, and many other aspects of DNA metabolism. The potential anti-cancer effects of thiosemicarbazones (TSC) and metal-TSC complexes have been demonstrated to target several biological processes, including DNA metabolism. Human topoisomerases were discovered among the molecular targets for TSCs, and metal-chelated TSCs specifically displayed significant inhibition of topoisomerase II. The processes by which metal-TSCs or TSCs inhibit topoisomerases are still being studied. In this brief review, we summarize the TSCs and metal-TSCs that inhibit various types of human topoisomerases, and we note some of the key unanswered questions regarding this interesting class of diverse compounds.

The coordination modes of (thio)semicarbazone copper(II) complexes strongly modulate the solution chemical properties and mechanism of anticancer activity

Thiosemicarbazones are promising candidates for anticancer therapy and their mechanism of action is often linked to their metal chelating ability. In this study, five (thio)semicarbazones with different donor sets (NNS, NNO, ONS, ONO) were selected and their behaviour in aqueous solution, the stability of their copper(II) complexes in addition to their cytotoxicity, DNA-binding, DNA cleavage ability and inhibition of topoisomerase IIα were investigated and compared. We aimed to reveal relationships between the structural variations, the significantly different physico-chemical properties, solution speciation and biological activity. The cytotoxicity of the ligands did not show correlation with the solubility, lipophilicity and permeability; and the decreased activity of the oxygen donor containing compounds was explained by their stronger preference towards chelation of iron(III) over iron(II). Meanwhile, among the copper complexes the most lipophilic species with the highest stability and membrane permeability exhibited the highest cytotoxicity. The studied copper(II) complexes interact with DNA, and reaction with glutathione led to heavy DNA cleavage in the case of the highly stable complexes which could be reduced in a reversible reaction with moderate rate. All the tested copper complexes inhibited topoisomerase IIα, however, this property of the complexes with low stability is most probably linked to the liberated free copper(II).

Investigations of Bis(alkylthiocarbamato)copper Linkage Isomers

Linkage isomers are coordination compounds with the same composition but different donor atoms, resulting in distinct physical and electronic structures. A pair of linkage isomers, CuL⁵⁵⁵ and CuL⁴⁶⁵, derived from phenylglyoxal bis(ethylthiocarbamate) were synthesized, isolated, and characterized by structural, electrochemical, and spectroscopic methods. The isomers are stable in solution under ambient conditions, but CuL⁴⁶⁵ converts to CuL⁵⁵⁵ in acid, consistent with quantum-chemical calculations. The complexes were screened against a lung adenocarcinoma cell line (A549) and a nonmalignant lung fibroblast cell line (IMR-90) to evaluate the antiproliferation activity. CuL⁵⁵⁵ and CuL⁴⁶⁵ possessed EC₅₀ values of 0.113 ± 0.030 and 0.115 ± 0.038 μM for A549 and 1.87 ± 0.29 and 0.77 ± 0.22 μM for IMR-90, respectively.

A new bio-active asymmetric-Schiff base: synthesis and evaluation of calf thymus DNA interaction, topoisomerase IIα inhibition, in vitro antiproliferative activity, SEM analysis and molecular docking studies

In this paper, the asymmetric-Schiff base 2-(4-(2-hydroxybenzylideneamino)benzylideneamino)benzoic acid (SB-2) was newly synthesized and characterized by various spectroscopic methods. The interaction of SB-2 with calf thymus DNA was investigated by UV-vis, fluorescence spectroscopy and molecular docking methods. It was determined that SB-2 effectively binds to DNA via the intercalation mode. DNA electrophoretic mobility experiments displayed that topoisomerase IIα could not cleave pBR322 plasmid DNA in the presence of SB-2, confirming that the Schiff base acts as a topo II suppressor. In the molecular docking studies, SB-2 was found to show an affinity for both the DNA-topoisomerase IIα complex and the DNA. In vitro antiproliferative activity of SB-2 was screened against HT-29 (colorectal) and HeLa (cervical) human tumor cell lines by MTT assay. SB-2 diminished the cell viability in a concentration- and incubation time-dependent manner. The ability of SB-2 to measure DNA damage in tumor cells was evaluated with cytokinesis-block micronucleus assay after incubation 24 h and 48 h. Light and scanning electron microscopy experiments of tumor cells demonstrated an incubation time-dependent increase in the proportion of apoptotic cells (nuclear condensation and apoptotic bodies) suggesting that autophagy and apoptosis play a role in the death of cells. Based on the obtained results, it may be considered that SB-2 is a candidate for DNA-targeting antitumor drug.Communicated by Ramaswamy H. Sarma.

Anticancer activity, DNA binding and docking study of M(ii)-complexes (M = Zn, Cu and Ni) derived from a new pyrazine–thiazole ligand: synthesis, structure and DFT

A series of structurally related Zn(ii), Cu(ii) and Ni(ii) complexes of 4-(2-(2-(1-(pyrazin-2-yl)ethylidene)hydrazinyl)-thiazol-4-yl)-benzonitrile (PyztbH) have been synthesized and characterized by spectroscopy, single crystal X-ray crystallography and density functional theory (DFT).

Copper Complexes as Anticancer Agents Targeting Topoisomerases I and II

Organometallics, such as copper compounds, are cancer chemotherapeutics used alone or in combination with other drugs. One small group of copper complexes exerts an effective inhibitory action on topoisomerases, which participate in the regulation of DNA topology. Copper complexes inhibitors of topoisomerases 1 and 2 work by different molecular mechanisms, analyzed herein. They allow genesis of DNA breaks after the formation of a ternary complex, or act in a catalytic mode, often display DNA intercalative properties and ROS production, and sometimes display dual effects. These amplified actions have repercussions on the cell cycle checkpoints and death effectors. Copper complexes of topoisomerase inhibitors are analyzed in a broader synthetic view and in the context of cancer cell mutations. Finally, new emerging treatment aspects are depicted to encourage the expansion of this family of highly active anticancer drugs and to expend their use in clinical trials and future cancer therapy.

Preparation, characterization, and anticancer efficacy of novel cobalt oxide nanoparticles conjugated with thiosemicarbazide

Gastric cancer is one of the most common cancers in modern societies. Previous studies have shown that the use of nanoparticle complexes is effective in the treatment of cancer. The aim of this study was to investigate the cytotoxicity and anticancer properties of cobalt oxide (Co₃O₄) nanoparticles (NPs) functionalized by glutamic acid (Glu) and conjugated with thiosemicarbazide (TSC) on gastric cancer (AGS) cell line. First, the Co₃O₄@Glu/TSC nanoparticles were synthesized via co-condensation reaction. Fourier-transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) tests were performed for identifying the morphology, structure, size and functional groups of produced nanoparticles. MTT assay was also performed to evaluate cytotoxicity effect. Moreover, Annexin V/PI staining with flow cytometry analysis, caspase-3 activation assay, and Hoechst 33258 staining was carried out for evaluating apoptosis. The FTIR results showed that the components of Co₃O₄@Glu/TSC NPs complex were successfully fabricated. Crystallographic structure of Co₃O₄@Glu/TSC NPs was confirmed by XRD patterns. SEM results indicated that the size of the nanoparticles was in the range of 16-40 nm. An EDX spectrum was determined and data explained the existence of cobalt as the prominent element. MTT test results showed that AGS cell life was significantly decreased compared to the control group with increasing concentration of nanoparticles (dose-dependent) (P < 0.05), IC₅₀ = 107.5 μg/mL. The results of flow cytometry assay and caspase-3 activity showed that fabricated Co₃O₄@Glu/TSC NPs induced apoptosis in the treated group. Moreover, Co₃O₄@Glu/TSC NPs treated AGS cells indicate an increase in the apoptotic characteristics including nuclear fragmentation. In the current work, the promising cytotoxicity and anti-cancer activities of Co₃O₄@Glu/TSC NPs complex toward gastric cancer (AGS) cell line were showed and it can be suggested for the drug delivery system.

Enhanced selectivity, cellular uptake, and in vitro activity of an intrinsically fluorescent copper-tirapazamine nanocomplex for hypoxia targeted therapy in prostate cancer

In the present work, a copper-tirapazamine (TPZ) nanocomplex [Cu(TPZ)₂] was synthesized for selective hypoxia-targeted therapy. The nanocomplex revealed a crystalline form, and exhibited higher lipophilicity, compared to TPZ. Furthermore, its stability was confirmed in different media, with minimum dissociation in serum (∼20% up to 72 h). In contrast to other hypoxia-targeted agents, our intrinsically fluorescent nanocomplex offered an invaluable tool to monitor its cellular uptake and intracellular distribution under both normoxia and hypoxia. The conferred higher cellular uptake of the nanocomplex, especially under hypoxia, and its biocompatible reductive potential resulted in superior hypoxia selectivity in two prostate cancer (PC) cell lines. More promisingly, the nanocomplex showed higher potency in three-dimensional tumor spheroids, compared to TPZ, due to its slower metabolism, and probably deeper penetration in tumor spheroids. Interestingly, the nuclear localization of the intact nanocomplex, combined with its higher DNA binding affinity, as evidenced by the DNA binding assay, resulted in significant S-phase cell-cycle arrest, followed by apoptosis in the three-dimensional spheroid model. In conclusion, the presented findings suggested that the Cu(TPZ)₂ nanocomplex can be a promising hypoxia-targeted therapeutic, which could potentiate the efficacy of the existing chemo- and radiotherapy in PC.

Bioactive Salen-type Schiff Base Transition Metal Complexes as Possible Anticancer Agents

Although metal-based anticancer drugs have been recognized as the most effective agents over the organic compounds, non-selectivity and high toxic effects have limited their applications in a way that only three Pt-analogues have progressed into clinical use. These problems have spurred chemists to develop different strategies based on alternative targets. This work focuses on predicting potency and mode of interactions of a series of salen type Schiff base transition metal complexes derived from meso-1,2-diphenyl-1,2-ethylenediamine, over some proteins (HDAC7, HDAC2, CatB, B-RAF kinase, TopII, RNR, TS, and rHA) using computational docking method, to be later considered as possible anticancer agents. The obtained results showed that all complexes exhibited higher affinity for HDAC7 than the other targets. Moreover, the bromo-derivatives of the copper compounds were more active on HDAC7 than the other derivatives. Such bromo compounds showed considerable interactions with Kinase, RNR, TS, and CatB. Contrary to Histone deacetylase (HAD)C7; HDAC2 was predicted to be relatively poor target. As expected, formation of the hydrophobic interactions between the metal complexes and the protein targets were essential for activity of the metal compounds. This study provides some more information for further optimizations and development of new metallodrugs as enzyme inhibitors for potential therapeutic agents.

Synthesis, characterization, DNA binding, topoisomerase inhibition, and apoptosis induction studies of a novel cobalt(III) complex with a thiosemicarbazone ligand

In this study, 9-anthraldehyde-N(4)-methylthiosemicarbazone (MeATSC) 1 and [Co(phen)2(O2CO)]Cl·6H2O 2 (where phen = 1,10-phenanthroline) were synthesized. [Co(phen)2(O2CO)]Cl·6H2O 2 was used to produce anhydrous [Co(phen)2(H2O)2](NO3)33. Subsequently, anhydrous [Co(phen)2(H2O)2](NO3)33 was reacted with MeATSC 1 to produce [Co(phen)2(MeATSC)](NO3)3·1.5H2O·C2H5OH 4. The ligand, MeATSC 1 and all complexes were characterized by elemental analysis, FT IR, UV-visible, and multinuclear NMR (1H, 13C, and 59Co) spectroscopy, along with HRMS, and conductivity measurements, where appropriate. Interactions of MeATSC 1 and complex 4 with calf thymus DNA (ctDNA) were investigated by carrying out UV-visible spectrophotometric studies. UV-visible spectrophotometric studies revealed weak interactions between ctDNA and the analytes, MeATSC 1 and complex 4 (Kb = 8.1 × 105 and 1.6 × 104 M-1, respectively). Topoisomerase inhibition assays and cleavage studies proved that complex 4 was an efficient catalytic inhibitor of human topoisomerases I and IIα. Based upon the results obtained from the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay on 4T1-luc metastatic mammary breast cancer cells (IC50 = 34.4 ± 5.2 μM when compared to IC50 = 13.75 ± 1.08 μM for the control, cisplatin), further investigations into the molecular events initiated by exposure to complex 4 were investigated. Studies have shown that complex 4 activated both the apoptotic and autophagic signaling pathways in addition to causing dissipation of the mitochondrial membrane potential (ΔΨm). Furthermore, activation of cysteine-aspartic proteases3 (caspase 3) in a time- and concentration-dependent manner coupled with the ΔΨm, studies implicated the intrinsic apoptotic pathway as the major regulator of cell death mechanism.

Thiosemicarbazone-metal complexes exhibiting cytotoxicity in colon cancer cell lines through oxidative stress

Colorectal cancer is the third most common type of cancer and has a high incidence in developed countries. At present, specific treatments are being required to allow individualized therapy depending on the molecular alteration on which the drug may act. The aim of this project is to evaluate whether HPTSC and HPTSC* thiosemicarbazones (HPTSC = pyridine-2-carbaldehyde thiosemicarbazone and HPTSC* = pyridine-2-carbaldehyde 4N-methylthiosemicarbazone), and their complexes with different transition metal ions as Cu(II), Fe(III) and Co(III), have antitumor activity in colon cancer cells (HT-29 and SW-480), that have different oncogenic characteristics. Cytotoxicity was evaluated and the involvement of oxidative stress in its mechanism of action was analyzed by quantifying the superoxide dismutase activity, redox state by quantification of the thioredoxin levels and reduced/oxidized glutathione rate and biomolecules damage. The apoptotic effect was evaluated by measurements of the levels of caspase 9 and 3 and the index of histones. All the metal-thiosemicarbazones have antitumor activity mediated by oxidative stress. The HPTSC*-Cu was the compound that showed the best antitumor and apoptotic characteristics for the cell line SW480, that is KRAS gene mutated.

From coins to cancer therapy: Gold, silver and copper complexes targeting human topoisomerases

Cancer is a complex issue and, even though the prevention basics and therapy have been implemented, it is still the second leading death cause worldwide. With the hope to discover new powerful and safer molecules to fight cancer, many researchers focused their attention on metal-based compounds, starting from the most famous and successfully employed anticancer drug, i.e. cisplatin. The current article aims to report the most recent discoveries about the use of gold, silver and copper complexes as antitumor agents, highlighting their influences on important enzymes, namely human topoisomerases. The latter are fundamental for the cell life and, if overexpressed, strongly implicated in cancer onset and progression. The identification of lead complexes targeting human topoisomerases and gifted with the appropriate chemical and pharmacological properties represents a fecund starting point to obtain new and more effective anticancer molecules.

Topoisomerase inhibitors: Pharmacology and emerging nanoscale delivery systems

Topoisomerase enzymes have shown unique roles in replication and transcription. These enzymes which were initially found in Escherichia coli have attracted considerable attention as target molecules for cancer therapy. Nowadays, there are several topoisomerase inhibitors in the market to treat or at least control the progression of cancer. However, significant toxicity, low solubility and poor pharmacokinetic properties have limited their wide application and these characteristics need to be improved. Nano-delivery systems have provided an opportunity to modify the intrinsic properties of molecules and also to transfer the toxic agent to the target tissues. These delivery systems leads to the re-introduction of existing molecules present in the market as novel therapeutic agents with different physicochemical and pharmacokinetic properties. This review focusses on a variety of nano-delivery vehicles used for the improvement of pharmacological properties of topoisomerase inhibitors and thus enabling their potential application as novel drugs in the market.

Design, synthesis and characterization of copper-based coordination compounds with bidentate (N,N and N,O) ligands: reversible uptake of iodine, dye adsorption and assessment of their antibacterial properties

This work presents the synthesis of close-packed copper complexes with an uncommon ability for dye and iodine adsorption and antibacterial activities.

Novel Survivin Inhibitor for Suppressing Pancreatic Cancer Cells Growth via Downregulating Sp1 and Sp3 Transcription Factors

BACKGROUND/AIMS

Targeting survivin, an anti-apoptotic protein and mitotic regulator, is considered as an effective therapeutic option for pancreatic cancer (PaCa). Tolfenamic acid (TA) showed anti-cancer activity in pre-clinical studies. A recent discovery demonstrated a copper(II) complex of TA (Cu-TA) can result in higher activity. In this study, the ability of Cu-TA to inhibit survivin and its transcription factors, Specificity protein (Sp) 1 and 3 in PaCa cell lines and tumor growth in mouse xenograft model were evaluated.

METHODS

Cell growth inhibition was measured in MIA PaCa-2 and Panc1 cells for 2 days using CellTiter-Glo kit. Sp1, Sp3 and survivin expression (by Western blot and qPCR), apoptotic cells and cell cycle phase distribution (by flow cytometry) were evaluated. A pilot study was performed using athymic nude mice [treated with vehicle/Cu-TA (25 or 50 mg/kg) 3 times/week for 4 weeks.

RESULTS

The IC50 value for Cu-TA was about half than TA.Both agents repressed the protein expression of Sp1/Sp3/survivin, Cu-TA was more effective than TA. Especially effect on survivin inhibition was 5.2 (MIA PaCa-2) or 6.4 (Panc1) fold higher and mRNA expression of only survivin was decreased. Apoptotic cells increased with Cu-TA treatment in both cell lines, while Panc1 showed both effect on apoptosis and cell cycle (G2/M) arrest. Cu-TA decreased the tumor growth in mouse xenografts (25 mg/kg: 48%; 50 mg/kg: 68%). Additionally, there was no change observed in mice body weights, indicating no overt toxicity was occurring.

CONCLUSION

These results show that Cu-TA can serve as an effective survivin inhibitor for inhibiting PaCa cell growth.

Cu(ii), Ga(iii) and In(iii) complexes of 2-acetylpyridine N(4)-phenylthiosemicarbazone: synthesis, spectral characterization and biological activities

In this paper, synthesis and characterization of metal complexes [Cu2(L)3]ClO4 (1), [Ga(L)2]NO3·2H2O (2) and [In(L)2]NO3·H2O (3) (HL = 2-acetylpyridine N(4)-phenylthiosemicarbazone) was carried out, including elemental analysis, spectral analysis (IR, UV-vis, NMR), and X-ray crystallography. Complex 1 contains one S-bridged binuclear [Cu2(L)3]+ unit, where two Cu atoms display diverse coordination geometries: one being square planar geometry and the other octahedral geometry. Both 2 and 3 are mononuclear complexes, and the metal centers in 2 and 3 are chelated by two NNS tridentate ligands possessing a distorted octahedral geometry. Biological studies show that all the complexes possess a wide spectrum of modest to effective antibacterial activities and remarkable cytotoxicities against HepG2 cells, and 1, in particular, with an IC50 value of 0.19 ± 0.06 μM, is 113-fold and 28-fold more cytotoxic than HL and the antitumor drug mitoxantrone, respectively. In addition, 3 exhibits excellent photoluminescence properties. Upon the addition of 1 equiv of In3+ ions, a remarkable fluorescence intensity of HL and fluorescent color change (from transparent to light-green) could be observed with 365 nm light, indicating that this ligand may be used as a promising colorimetric and fluorescent probe for In3+ detection.

A novel β-diiminato manganeseIII complex as the promising anticancer agent induces G0/G1 cell cycle arrest and triggers apoptosis via mitochondrial-dependent pathways in MCF-7 and MDA-MB-231 human breast cancer cells

Novel β-diiminato manganese^III complex has shown promising anti-breast cancer activity.

Topoisomerases: Resistance versus Sensitivity, How Far We Can Go?

DNA topoisomerases are ubiquitously present remarkable molecular machines that help in altering topology of DNA in living cells. The crucial role played by these nucleases during DNA replication, transcription, and recombination vis-à-vis less sequence similarity among different species makes topoisomerases unique and attractive targets for different anticancer and antibacterial drugs. However, druggability of topoisomerases by the existing class of molecules is increasingly becoming questationable due to resistance development predominated by mutations in the corresponding genes. The current scenario facing a decline in the development of new molecules further comprises an important factor that may challenge topoisomerase-targeting therapy. Thus, it is imperative to wisely use the existing inhibitors lest with this rapid rate of losing grip over the target we may not go too far. Furthermore, it is important not only to design new molecules but also to develop new approaches that may avoid obstacles in therapies due to multiple resistance mechanisms. This review provides a succinct account of different classes of topoisomerase inhibitors, focuses on resistance acquired by mutations in topoisomerases, and discusses the various approaches to increase the efficacy of topoisomerase inhibitors. In a later section, we also suggest the possibility of using bisbenzimidazoles along with efflux pump inhibitors for synergistic bactericidal effects.