The Combined Therapeutical Effect of Metal-based Drugs and Radiation Therapy: The Present Status of Research

Comprehensive Insights into Medicinal Research on Imidazole-Based Supramolecular Complexes

The electron-rich five-membered aromatic aza-heterocyclic imidazole, which contains two nitrogen atoms, is an important functional fragment widely present in a large number of biomolecules and medicinal drugs; its unique structure is beneficial to easily bind with various inorganic or organic ions and molecules through noncovalent interactions to form a variety of supramolecular complexes with broad medicinal potential, which is being paid an increasing amount of attention regarding more and more contributions to imidazole-based supramolecular complexes for possible medicinal application. This work gives systematical and comprehensive insights into medicinal research on imidazole-based supramolecular complexes, including anticancer, antibacterial, antifungal, antiparasitic, antidiabetic, antihypertensive, and anti-inflammatory aspects as well as ion receptors, imaging agents, and pathologic probes. The new trend of the foreseeable research in the near future toward imidazole-based supramolecular medicinal chemistry is also prospected. It is hoped that this work provides beneficial help for the rational design of imidazole-based drug molecules and supramolecular medicinal agents and more effective diagnostic agents and pathological probes.

Novel Silver Complexes Based on Phosphanes and Ester Derivatives of Bis(pyrazol-1-yl)acetate Ligands Targeting TrxR: New Promising Chemotherapeutic Tools Relevant to SCLC Management

Bis(pyrazol-1-yl)acetic acid (HC(pz)₂COOH) and bis(3,5-dimethyl-pyrazol-1-yl)acetic acid (HC(pz^Me2)₂COOH) were converted into the methyl ester derivatives 1 (L^OMe) and 2 (L^2OMe), respectively, and were used for the preparation of silver(I) complexes 3-5. The Ag(I) complexes were prepared by the reaction of AgNO₃ and 1,3,5-triaza-7-phosphaadamantane (PTA) or triphenylphosphine (PPh₃) with L^OMe and L^2OMe in methanol solution. All Ag(I) complexes showed a significant in vitro antitumor activity, proving to be more effective than the reference drug cisplatin in the in-house human cancer cell line panel containing examples of different solid tumors. Compounds were particularly effective against the highly aggressive and intrinsically resistant human small-cell lung carcinoma (SCLC) cells, either in 2D and 3D cancer cell models. Mechanistic studies revealed their ability to accumulate into cancer cells and to selectively target Thioredoxin (TrxR), thus leading to redox homeostasis unbalance and ultimately inducing cancer cell death through apoptosis.

Aspirin Repurposing in Folate-Decorated Nanoparticles: Another Way to Target Breast Cancer

Breast cancer affects more than 1 million women per year worldwide. Through this study, we developed a nanoparticle-based drug delivery system to target breast cancer cells. Aspirin has been found to inhibit thromboembolic diseases with its tumor-preventing activity. As a consequence, it relieves disease symptoms and severity. Here, mesoporous silica nanoparticles (MNPs) have been used to deliver aspirin to the tumor location. MNP-based aspirin in folic acid (F)-conjugated polydopamine (MNP-Asp-PD-PG-F) vehicles are prepared for targeted breast cancer therapy. The vehicle hinges on MNP altered with polymer polyethylene glycol (PG), polydopamine (PD), and F. The delivery vehicle was studied for in vitro drug release, cytotoxicity, and breast cancer cell proliferation. F-conjugated drug delivery vehicles let MNPs achieve an elevated targeting efficacy, ideal for cancer therapy. It was also observed that compared to free aspirin, our drug delivery system (MNP-Asp-PD-PG-F) has a higher cytotoxic and antiproliferative effect on breast cancer cells. The drug delivery system can be proposed as a targeted breast cancer therapy that could be further focused on other targeted cancer therapies. Delivering aspirin by the PD-PG-F system on the tumor sites promises a therapeutic potential for breast cancer treatment.

Interaction of Carrier Protein with Potential Metallic Drug Candidate N-Glycoside 'GATPT': Validation by Multi-Spectroscopic and Molecular Docking Approaches

Lysozyme is often used as a model protein to study interaction with drug molecules and to understand biological processes which help in illuminating the therapeutic effectiveness of the drug. In the present work, in vitro interaction studies of 1-{(2-hydroxyethyl)amino}-2-amino-1,2-dideoxy-d-glucose triphenyl tin (IV) (GATPT) complex with lysozyme were carried out by employing various biophysical methods such as absorption, fluorescence, and circular dichroism (CD) spectroscopies. The experimental results revealed efficient binding affinity of GATPT with lysozyme with intrinsic binding (Kb) and binding constant (K) values in the order of 105 M-1. The number of binding sites and thermodynamic parameters ΔG, ΔH, and ΔS at four different temperatures were also calculated and the interaction of GATPT with lysozyme was found to be enthalpy and entropy driven. The CD spectra revealed alterations in the population of α-helical content within the secondary structure of lysozyme in presence of GATPT complex. The morphological analysis of the complex with lysozyme and lysozyme-DNA condensates was carried out by employing confocal and SEM studies. Furthermore, the molecular docking studies confirmed the interaction of GATPT within the larger hydrophobic pocket of the lysozyme via several non-covalent interactions.

Artificial high-density lipoprotein-mimicking nanotherapeutics for the treatment of cardiovascular diseases

Despite the ability of current efficacious low-density lipoprotein-cholesterol-lowering therapies to reduce total cardiovascular disease (CVD) risks, CVD still poses major risks for morbidity and mortality to the general population. Because of the pleiotropic endothelial protective effects of high-density lipoproteins (HDL), the direct infusion of reconstituted HDL (rHDL) products, including MDCO-216, CER001, and CSL112, have been tested in clinical trials to determine whether direct infusion of rHDL can reduce coronary events in CVD patients. In addition to these rHDL products, in the past two decades, there has been an increased focused on designing artificial HDL-mimicking nanotherapeutics to produce complementary therapeutic strategies for CVD patients beyond lowering of atherogenic lipoproteins. Although recent reviews have comprehensively discussed the developments of artificial HDL-mimicking nanoparticles as therapeutics for CVD, there has been little assessment of "plain" or "drug-free" HDL-mimicking nanoparticles as therapeutics alone. In this review, we will summarize the clinical outcomes of rHDL products, examine recent advances in other types of artificial HDL-mimicking nanotherapeutics, including polymeric nanoparticles, cyclodextrins, micelles, metal nanoparticles, and so on; and potential new approaches for future CVD interventions. Moreover, success stories, lessons, and interpretations of the utility and functionality of these HDL-mimicking nanotherapeutics will be an integral part of this article. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Cardiovascular Disease.

Requirements for Designing an Effective Metallic Nanoparticle (NP)-Boosted Radiation Therapy (RT)

Simple Summary

Recent advances in nanotechnology gave rise to trials with various types of metallic nanoparticles (NPs) to enhance the radiosensitization of cancer cells while reducing or maintaining the normal tissue complication probability during radiation therapy. This work reviews the physical and chemical mechanisms leading to the enhancement of ionizing radiation’s detrimental effects on cells and tissues, as well as the plethora of experimental procedures to study these effects of the so-called “NPs’ radiosensitization”. The paper presents the need to a better understanding of all the phases of actions before applying metallic-based NPs in clinical practice to improve the effect of IR therapy. More physical and biological experiments especially in vivo must be performed and simulation Monte Carlo or mathematical codes based on more accurate models for all phases must be developed.

Abstract

Many different tumor-targeted strategies are under development worldwide to limit the side effects and improve the effectiveness of cancer therapies. One promising method is to enhance the radiosensitization of the cancer cells while reducing or maintaining the normal tissue complication probability during radiation therapy using metallic nanoparticles (NPs). Radiotherapy with MV photons is more commonly available and applied in cancer clinics than high LET particle radiotherapy, so the addition of high-Z NPs has the potential to further increase the efficacy of photon radiotherapy in terms of NP radiosensitization. Generally, when using X-rays, mainly the inner electron shells are ionized, which creates cascades of both low and high energy Auger electrons. When using high LET particles, mainly the outer shells are ionized, which give electrons with lower energies than when using X-rays. The amount of the produced low energy electrons is higher when exposing NPs to heavy charged particles than when exposing them to X-rays. Since ions traverse the material along tracks, and therefore give rise to a much more inhomogeneous dose distributions than X-rays, there might be a need to introduce a higher number of NPs when using ions compared to when using X-rays to create enough primary and secondary electrons to get the desired dose escalations. This raises the questions of toxicity. This paper provides a review of the fundamental processes controlling the outcome of metallic NP-boosted photon beam and ion beam radiation therapy and presents some experimental procedures to study the biological effects of NPs’ radiosensitization. The overview shows the need for more systematic studies of the behavior of NPs when exposed to different kinds of ionizing radiation before applying metallic-based NPs in clinical practice to improve the effect of IR therapy.

Novel Copper(II) Complex with a 4-Acylpyrazolone Derivative and Coligand Induce Apoptosis in Liver Cancer Cells

A novel pyrazolone-based copper complex [CuL(phen)(CH₃OH)][CuL(phen)]·CH₃CH₂OH·CH₃OH (P-FAH-Cu-phen) was synthesized and characterized. The asymmetric structural unit of P-FAH-Cu-phen was composed of two independent complex units [CuL(phen)(CH₃OH)] and [CuL(phen)]:Cu1²⁺ center with six coordination mode and Cu2²⁺ center with five coordination mode. The growth of BEL-7404 cells and H22 cells was significantly inhibited by P-FAH-Cu-phen with IC₅₀ values of 1.175 μg/mL and 1.097 μg/mL, respectively, which were much lower than IC₅₀ of cisplatin for BEL-7404 cells (23.32 μg/mL) and H22 cells (27.5 μg/mL). P-FAH-Cu-phen induced cell cycle arrest at G2/M and apoptosis in BEL-7404 cells through mitochondria- and endoplasmic reticulum stress-associated pathways. Moreover, P-FAH-Cu-phen significantly suppressed the migration of BEL-7404 cells and the tumor growth in H22 tumor mouse model without severe side effects and improved the survival of tumor mice. The results suggested that P-FAH-Cu-phen might be a potential drug candidate for the treatment of live cancer.

Coinage Metal N-Heterocyclic Carbene Complexes: Recent Synthetic Strategies and Medicinal Applications

New weapons are constantly needed in the fight against cancer. The discovery of cisplatin as an anticancer drug prompted the search for new metal complexes. The successful history of cisplatin motivated chemists to develop a plethora of metal-based molecules. Among them, metal-N-heterocyclic carbene (NHC) complexes have gained significant attention because of their suitable qualities for efficient drug design. The enhanced applications of coinage metal-NHC complexes have encouraged a gradually increasing number of studies in the fields of medicinal chemistry that benefit from the fascinating chemical properties of these complexes. This review aims to present recent developments in synthetic strategies and medicinal applications of copper, silver and gold complexes supported by NHC ligands.

Syntheses and Reactivity of New Zwitterionic Imidazolium Trihydridoborate and Triphenylborate Species

In this study, four new N-(alkyl/aryl)imidazolium-borates were prepared, and their deprotonation reactions were investigated. Addition of BH₃•THF to N-benzylimidazoles and N-mesitylimidazoles leads to imidazolium-trihydridoborate adducts. Ammonium tetraphenylborate reacts with benzyl- or mesityl-imidazoles with the loss of one of the phenyl groups yielding the corresponding imidazolium-triphenylborates. Their authenticity was confirmed by CHN analysis, ¹H-NMR, ¹³C-NMR, ¹¹B-NMR, FT-IR spectroscopy, and electrospray ionization mass spectrometry (ESI-MS). 3-Benzyl-imidazolium-1-yl)trihydridoborate, (HIm^Bn)BH₃, and (3-mesityl-imidazolium-1-yl)trihydridoborate, (HIm^Mes)BH₃, were also characterized by X-ray crystallography. The reactivity of these new compounds as carbene precursors in an effort to obtain borate-NHC complexes was investigated and a new carbene-borate adduct (which dimerizes) was obtained via a microwave-assisted procedure.

Synthesis and identification of heteroaromatic N-benzyl sulfonamides as potential anticancer agents

Sulfonamides are a crucial class of bioisosteres that are prevalent in a wide range of pharmaceuticals, however, the available methods for their production directly from heteroaryl aldehyde reagents remains surprisingly limited. A new approach for regioselective incorporation of a sulfonamide unit to heteroarene scaffolds has been developed and is reported within. As a result, a variety of primary benzylic N-alkylsulfonamides have been prepared via a two-step (one pot) formation from the in situ reduction of an intermediate N-sulfonyl imine under mild, practical conditions. The compounds have been screened against a variety of cell lines for cytotoxicity effects using a Cell Titer Blue assay. The cell viability investigation identifies a subset of N-benzylic sulfonamides derived from the indole scaffold to be targeted for further development into novel molecules with potential therapeutic value. The most cytotoxic of the compounds prepared, AAL-030, exhibited higher potency than other well-known anticancer agents Indisulam and ABT-751.

Metal-based antitumor compounds: beyond cisplatin

Despite improvements in the 5-year survival rate to over 80% in cancers, such as Hodgkin lymphoma and testicular cancer, more aggressive tumors including pancreatic and brain cancer still have extremely low survival rates. The establishment of chemoresistance, responsible for the reduction in treatment efficiency and cancer relapse, is one possible explanation for this setback. Metal-based compounds, a class of anticancer drugs, are largely used in the treatment of cancer. Herein, we will review the use of metal-based small molecules in chemotherapy, focusing on recent studies, and we will discuss how new nonplatinum-based agents are prompting scientists to increase drug specificity to overcome chemoresistance in cancer cells.

Novel Pt(ii) complexes with modified aroyl-hydrazone Schiff-base ligands: synthesis, cytotoxicity and action mechanism

The complex-induced apoptosis of cancer cells via: (1) the mitochondrial pathway; (2) inserting into and cleaving DNA; and (3) inhibiting telomerase.

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

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

Syntheses and biological studies of nitroimidazole conjugated heteroscorpionate ligands and related Cu(I) and Cu(II) complexes

Copper(I) and copper(II) complexes of 5-nitroimidazole conjugated heteroscorpionate ligands have been synthesized. In particular, the new 2,2-bis(pyrazol-1-yl)-N-(2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethyl)acetamide ligand (L^HMN) was synthesized by direct coupling of preformed side chain acid with 5-nitroimidazole and its coordination chemistry was investigated towards Cu(I) and Cu(II) acceptors and compared with that of the related 2,2-bis(3,5-dimethyl-1-H-pyrazol-1-yl)-N-(2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethyl)acetamide ligand (L^MeMN). The copper(II) complexes {[(L^MeMN)₂Cu]Cl₂} and {[(L^HMN)₂Cu]Cl₂} were prepared by the reaction of CuCl₂·2H₂O with L^HMN or L^MeMN ligands in methanol solution. The water soluble copper(I) complexes {[(L^MeMN)Cu(PTA)₂]}(PF₆) and {[(L^HMN)Cu(PTA)₂]}(PF₆) were prepared by the reaction of Cu(CH₃CN)₄PF₆ and 1,3,5-triaza-7-phosphaadamantane (PTA) with L^HMN or L^MeMN ligands in acetonitrile solution. The new Cu(I) and Cu(II) complexes as well as the corresponding uncoordinated ligands were evaluated for their cytotoxic activity against 2D monolayer cultures of multiple human cancer cell lines and 3D-cultured HCT-15 colon cancer spheroids. Morphological analysis by Transmission Electron Microscopy (TEM) revealed the induction of a massive cytoplasmic vacuolization consistent with a paraptotic-like cancer cell death.

Structure and biological properties of five Pt(II) complexes as potential anticancer agents

We synthesized and validated five Schiff base Pt(II) complexes derived from 2-hydroxy-1-naphthaldehyde benzoyl hydrazone and its derivatives, which are modified at the benzohydrazide structures (L1-L5). The complexes were [Pt(L1)(DMSO)Cl] (C1), [Pt(L2)(DMSO)Cl] (C2), [Pt(L3)(DMSO)Cl] (C3), [Pt(L4)(DMSO)Cl] (C4), and [Pt(L5)(DMSO)Cl] (C5). Crystal structures showed that the Pt centers of all complexes were tetra-coordinated with other atoms. The structure-activity relationships and anticancer mechanisms of the complexes were explored. These five Pt(II) complexes were toxic at micromolar doses and exhibited cytotoxicity similar to or somewhat higher than that of cisplatin, with IC₅₀ values ranging from 4.38 μM to 25.16 μM. The complexes exerted chemotherapeutic effects via inhibition of telomerase by targeting the c-myc promoter and down-regulating the expression of human telomerase reverse transcriptase, consequently triggering cell apoptosis. In addition, Pt(II) complexes also caused cell cycle arrest at S-phase, leading to the down-regulation of cdc25 A, cyclin A2, and CDK2 and up-regulation of p53, p27, and p21 proteins. Other complex-associated events were reactive oxygen species production, transformation of the mitochondrial membrane potential (Δψ_m), release of cytochrome c, regulation of Bcl-2 family protein expression, facilitated release of apoptotic active substances, and activation of caspases to induce apoptosis.

Highly Electrophilic, Catalytically Active and Redox-Responsive Cobaltoceniumyl and Ferrocenyl Triazolylidene Coinage Metal Complexes

A convenient access to a triad of triazoles with ferrocenyl and cobaltoceniumyl substituents is reported. N-Alkylation, deprotonation and metalation with CuI /AgI /AuI synthons affords the heteroleptic triazolylidene complexes. Due to the combination of neutral, electron-donating ferrocenyl substituents and cationic, strongly electron-withdrawing cobaltocenium substituents, the mesoionic carbene (MIC) ligands of these complexes are electronically interesting "push-pull", "pull-push" and "pull-pull" metalloligands with further switchable redox states based on their fully reversible FeII /FeIII , (ferrocene/ferrocenium) and CoIII /CoII , (cobaltocenium/cobaltocene) redox couples. These are the first examples of metal complexes of (di)cationic NHC ligands based on cobaltoceniumyl substituents. DFT calculated Tolman electronic parameter (TEP) of the new MIC ligands, show these metalloligands to be extremely electron-poor NHCs with properties unmatched in other carbene chemistry. Utilization of these multimetallic electronically tunable compounds in catalytic oxazoline synthesis and in antitumor studies are presented. Remarkably, 1 mol % of the AuI complex with the dicationic MIC ligand displays full catalytic conversion, without the need for any other additives, in less than 2 hours at ambient temperatures. These results thus firmly establish these new classes of cobaltoceniumyl based (di)cationic MIC ligands as prominent players in several branches of chemistry.

Mechanisms Underlying Neurotoxicity of Silver Nanoparticles

The potent antimicrobial properties of nanoparticulate silver (AgNPs) have led to broad interest in using them in a wide range of commercial and medical applications. Although numerous in vivo and in vitro studies have provided evidence of toxic effects, rapid commercialization of AgNP-based nanomaterials has advanced without characterization of their potential environmental and health hazards. There is evidence that AgNPs can be translocated from the blood to the brain, regardless the route of exposure, and accumulate in the brain over time. As the brain is responsible for basic physiological functions and controls all human activities, it is important to assess the hazardous influence of AgNPs released from widely used nanoproducts and possible side effects of AgNP-based therapies. A number of studies have suggested that the size, shape and surface coating, as well as rates of silver ion release and interactions with proteins are the key factors determining the neurotoxicity of AgNPs. AgNPs target endothelial cells forming the blood-brain barrier, neurons and glial cells and leads finally to oxidative stress-related cell death. In this chapter, we review in detail current data on the impact of AgNPs on the central nervous system and discuss the possible mechanisms of their neurotoxic effects.

N-(2-methyl-indol-1H-5-yl)-1-naphthalenesulfonamide: A novel reversible antimitotic agent inhibiting cancer cell motility

A series of compounds containing the sulfonamide scaffold were synthesized and screened for their in vitro anticancer activity against a representative panel of human cancer cell lines, leading to the identification of N-(2-methyl-1H-indol-5-yl)-1-naphthalenesulfonamide (8e) as a compound showing a remarkable activity across the panel, with IC50 values in the nanomolar-to-low micromolar range. Cell cycle distribution analysis revealed that 8e promoted a severe G2/M arrest, which was followed by cellular senescence as indicated by the detection of senescence-associated β-galactosidase (SA-β-gal) in 8e-treated cells. Prolonged 8e treatment also led to the onset of apoptosis, in correlation with the detection of increased Caspase 3/7 activities. Despite increasing γ-H2A.X levels, a well-established readout for DNA double-strand breaks, in vitro DNA binding studies with 8e did not support interaction with DNA. In agreement with this, 8e failed to activate the cellular DNA damage checkpoint. Importantly, tubulin staining showed that 8e promoted a severe disorganization of microtubules and mitotic spindle formation was not detected in 8e-treated cells. Accordingly, 8e inhibited tubulin polymerization in vitro in a dose-dependent manner and was also able to robustly inhibit cancer cell motility. Docking analysis revealed a compatible interaction with the colchicine-binding site of tubulin. Remarkably, these cellular effects were reversible since disruption of treatment resulted in the reorganization of microtubules, cell cycle re-entry and loss of senescent markers. Collectively, our data suggest that this compound may be a promising new anticancer agent capable of both reducing cancer cell growth and motility.

Differences in predictions of ODE models of tumor growth: a cautionary example

BACKGROUND

While mathematical models are often used to predict progression of cancer and treatment outcomes, there is still uncertainty over how to best model tumor growth. Seven ordinary differential equation (ODE) models of tumor growth (exponential, Mendelsohn, logistic, linear, surface, Gompertz, and Bertalanffy) have been proposed, but there is no clear guidance on how to choose the most appropriate model for a particular cancer.

METHODS

We examined all seven of the previously proposed ODE models in the presence and absence of chemotherapy. We derived equations for the maximum tumor size, doubling time, and the minimum amount of chemotherapy needed to suppress the tumor and used a sample data set to compare how these quantities differ based on choice of growth model.

RESULTS

We find that there is a 12-fold difference in predicting doubling times and a 6-fold difference in the predicted amount of chemotherapy needed for suppression depending on which growth model was used.

CONCLUSION

Our results highlight the need for careful consideration of model assumptions when developing mathematical models for use in cancer treatment planning.

Glucose is a key driver for GLUT1-mediated nanoparticles internalization in breast cancer cells

The mesenchymal state in cancer is usually associated with poor prognosis due to the metastatic predisposition and the hyper-activated metabolism. Exploiting cell glucose metabolism we propose a new method to detect mesenchymal-like cancer cells. We demonstrate that the uptake of glucose-coated magnetic nanoparticles (MNPs) by mesenchymal-like cells remains constant when the glucose in the medium is increased from low (5.5 mM) to high (25 mM) concentration, while the MNPs uptake by epithelial-like cells is significantly reduced. These findings reveal that the glucose-shell of MNPs plays a major role in recognition of cells with high-metabolic activity. By selectively blocking the glucose transporter 1 channels we showed its involvement in the internalization process of glucose-coated MNPs. Our results suggest that glucose-coated MNPs can be used for metabolic-based assays aimed at detecting cancer cells and that can be used to selectively target cancer cells taking advantage, for instance, of the magnetic-thermotherapy.

Metal-based drugs that break the rules

Cisplatin and other platinum compounds have had a huge impact in the treatment of cancers and are applied in the majority of anticancer chemotherapeutic regimens. The success of these compounds has biased the approaches used to discover new metal-based anticancer drugs. In this perspective we highlight compounds that are apparently incompatible with the more classical (platinum-derived) concepts employed in the development of metal-based anticancer drugs, with respect to both compound design and the approaches used to validate their utility. Possible design approaches for the future are also suggested.

Mono-, bi- and multi-nuclear silver complexes constructed from bis(benzimidazole)-2-oxapropane ligands and methacrylate: syntheses, crystal structures, DNA-binding properties and antioxidant activities

Three mono-, bi- and multi-nuclear Ag(i) complexes have been synthesized and characterized systematically. The complexes bind to DNA in a intercalate mode. Complex2has the potential ability to scavenge hydroxyl radicals inin vitrostudies.

Radiobiological modifiers in clinical radiation oncology: current reality and future potential

Radiation therapy can successfully ablate tumors. However, the same ionization process that destroys a cancer can also permanently damage surrounding organs resulting in unwanted clinical morbidity. Therefore, modern radiation therapy attempts to minimize dose to normal tissue to prevent side effects. Still, as tumors and normal tissues intercalate, the risk of normal tissue injury often may prevent tumoricidal doses of radiation therapy to be delivered. This paper will review current outcomes and limitations of radiobiological modifiers that may selectively enhance the radiosensitivity of tumors as well as parallel techniques that may protect normal tissues from radiation injury. Future endeavors based in part upon newly elucidated genetic pathways will be highlighted.

Hydrogen bonding and anticancer properties of water-soluble chiral p-cymene Ru(II) compounds with amino-oxime ligands

The investigation of the hydrogen-bonding effect on the aggregation tendency of ruthenium compounds [(η⁶-p-cymene)Ru(κNHR,κNOH)Cl]Cl (R = Ph (1a), Bn (1b)) and [(η⁶-p-cymene)Ru(κ²NH(2-pic),κNOH)][PF₆]₂ (1c), [(η⁶-p-cymene)Ru(κNHBn,κNO)Cl] (2b) and [(η⁶-p-cymene)Ru(κNBn,κ²NO)] (3b), has been performed by means of concentration dependence ¹H NMR chemical shifts and DOSY experiments. The synthesis and full characterization of new compounds 1c, [(η⁶-p-cymene)Ru(κNPh,κ²NO)] (3a) and 3b are also reported. The effect of the water soluble ruthenium complexes 1a-1c on cytotoxicity, cell adhesion and cell migration of the androgen-independent prostate cancer PC3 cells have been assessed by MTT, adhesion to type-I-collagen and recovery of monolayer wounds assays, respectively. Interactions of 1a-1c with DNA and human serum albumin have also been studied. Altogether, the properties reported herein suggest that ruthenium compounds 1a-1c have considerable potential as anticancer agents against advanced prostate cancer.

Novel triazolium based 11th group NHCs: synthesis, characterization and cellular response mechanisms

The novel NHC ligand precursor 1,4-bis(4-nitrobenzyl)-1H-1,2,4-triazol-4-ium bromide, [HTz^(pNO2Bz)2]Br, has been synthesized and used in the synthesis of the corresponding metal complexes M[Tz^(pNO2Bz)2]Br (M = Cu(i), Ag(i) or Au(i)).

A selenium-containing ruthenium complex as a cancer radiosensitizer, rational design and the important role of ROS-mediated signalling

We have described the rational design of selenium-containing ruthenium complexes and their use as cancer radiosensitizers through regulating ROS-mediated pathways.