👤 Thorne N

Ferroptosis is a type of programmed cell death characterized by accumulation of free iron, reactive oxygen species generation and lipid peroxidation and is distinct from other types of regulated cell deaths such as apoptosis, necrosis and autophagy. Ferroptosis is distinct from other programmed cell deaths for its iron dependence and its significant role in tumor suppression. Therefore, harnessing ferroptosis may offer promising avenues for cancer therapy. In the present review, the different pathways that lead to ferroptosis, the genes and transcription factors involved in both iron and lipid metabolism, as well as the impact of small‑molecule alterations on the regulation of ferroptotic cell death, were discussed. Furthermore, the emergence of combination therapies with ferroptosis‑inducing molecules that overcome resistance to conventional chemotherapy, particularly in solid tumors, were highlighted. Show less

Corrinoids are cobalt-containing tetrapyrroles. They include adenosylcobalamin (vitamin B12) and cobamides that function as cofactors and coenzymes for methyl transfer, radical-dependent and redox reactions. Though cobamides are the most complex cofactors in nature, they are essential in the acetyl-CoA pathway, thought to be the most ancient CO2-fixation pathway, where they perform a pterin-to-cobalt-to-nickel methyl transfer reaction catalyzed by the corrinoid iron-sulphur protein (CoFeS). CoFeS occurs in H2-dependent archaeal methanogens, the oldest microbial lineage by measure of physiology and carbon isotope data, dating corrinoids to ca. 3.5 billion years. However, CoFeS and cobamides are also essential in the acetyl-CoA pathway of H2-dependent bacterial acetogens. To determine whether corrin biosynthesis was established before archaea and bacteria diverged, whether the pathways arose independently or whether cobamide biosynthesis was transferred from the archaeal to the bacterial lineage (or vice versa) during evolution, we investigated phylogenies and structural data for 26 enzymes of corrin ring and lower ligand biosynthesis. The data trace cobamide synthesis to the common ancestor of bacteria and archaea, placing it in the last universal common ancestor of all lifeforms (LUCA), while pterin-dependent methyl synthesis pathways likely arose independently post-LUCA in the lineages leading to bacteria and archaea. Enzymes of corrin biosynthesis were recruited from preexisting ancient pathways. Evolutionary forerunners of CoFeS function were likely Fe-, Ni- and Co-containing solid-state surfaces, which, in the laboratory, catalyze the reactions of the acetyl-CoA pathway from CO2 to pyruvate under serpentinizing hydrothermal conditions. The data suggest that enzymatic corrin biosynthesis replaced insoluble solid-state catalysts that tethered primordial CO2 assimilation to the Earth's crust, suggesting a role for corrin synthesis in the origin of free-living cells. Show less

Geological structures known as alkaline hydrothermal vents (AHVs) likely displayed dynamic energy characteristics analogous to cellular chemiosmosis and contained iron-oxyhydroxide green rusts in the early Earth. Under specific conditions, those minerals could have acted as non-enzymatic catalysts in the development of early bioenergetic chemiosmotic energy systems while being integrated into the membrane of AHV-produced organic vesicles. Here, we show that the simultaneous addition of two probable AHV components, namely nickel and amino acids, impacts green rust's physico-chemical properties, especially those required for its incorporation in lipid vesicle's membranes, such as decreasing the mineral size to the nanometer scale and increasing its hydrophobicity. These results suggest that such hydrophobic nano green rusts could fit into lipid vesicle membranes and could have functioned as a primitive, inorganic precursor to modern chemiosmotic metalloenzymes, facilitating both electron and proton transport in early life-like systems. Show less

The tumor suppressor protein, p53, which is mutated in half of human tumors, plays a critical role in cellular responses to DNA damage and maintenance of genome stability. Therefore, increasing our understanding of the p53 pathway is essential for improving cancer treatment and diagnosis. Show less

Ferroptosis, a novel form of regulated cell death induced by the excessive accumulation of lipid peroxidation products, plays a pivotal role in the suppression of tumorigenesis. Two prominent mitochondrial ferroptosis defense systems are glutathione peroxidase 4 (GPX4) and dihydroorotate dehydrogenase (DHODH), both of which are localized within the mitochondria. However, the existence of supplementary cellular defense mechanisms against mitochondrial ferroptosis remains unclear. Our findings unequivocally demonstrate that inactivation of mitochondrial respiratory chain complex I (MCI) induces lipid peroxidation and consequently invokes ferroptosis across GPX4 low-expression cancer cells. However, in GPX4 high expression cancer cells, the MCI inhibitor did not induce ferroptosis, but increased cell sensitivity to ferroptosis induced by the GPX4 inhibitor. Overexpression of the MCI alternative protein yeast NADH-ubiquinone reductase (NDI1) not only quells ferroptosis induced by MCI inhibitors but also confers cellular protection against ferroptosis inducers. Mechanically, MCI inhibitors actuate an elevation in the NADH level while concomitantly diminishing the CoQH2 level. The manifestation of MCI inhibitor-induced ferroptosis can be reversed by supplementation with mitochondrial-specific analogues of CoQH2. Notably, MCI operates in parallel with mitochondrial-localized GPX4 and DHODH to inhibit mitochondrial ferroptosis, but independently of cytosolically localized GPX4 or ferroptosis suppressor protein 1(FSP1). The MCI inhibitor IACS-010759, is endowed with the ability to induce ferroptosis while concurrently impeding tumor proliferation in vivo. Our results identified a ferroptosis defense mechanism mediated by MCI within the mitochondria and suggested a therapeutic strategy for targeting ferroptosis in cancer treatment. Show less

Modern quantitative image analysis techniques have enabled high-throughput, high-content imaging experiments. Image-based profiling leverages the rich information in images to identify similarities or differences among biological samples, rather than measuring a few features, as in high-content screening. Here, we review a decade of advancements and applications of Cell Painting, a microscopy-based cell-labeling assay aiming to capture a cell's state, introduced in 2013 to optimize and standardize image-based profiling. Cell Painting's ability to capture cellular responses to various perturbations has expanded owing to improvements in the protocol, adaptations for different perturbations, and enhanced methodologies for feature extraction, quality control, and batch-effect correction. Cell Painting is a versatile tool that has been used in various applications, alone or with other -omics data, to decipher the mechanism of action of a compound, its toxicity profile, and other biological effects. Future advances will likely involve computational and experimental techniques, new publicly available datasets, and integration with other high-content data types. Show less

Despite advances in understanding genetic susceptibility to cancer, much of cancer heritability remains unidentified. At the same time, the makeup of industrial chemicals in our environment only grows more complex. This gap in knowledge on cancer risk has prompted calls to expand cancer research to the comprehensive, discovery-based study of nongenetic environmental influences, conceptualized as the "exposome." Show less

Ewing sarcoma (EwS) cell line culture largely relies on standard techniques, which do not recapitulate physiological conditions. Here, we report on a feasible and cost-efficient EwS cell culture technique with increased physiological relevance employing an advanced medium composition, reduced fetal calf serum, and spheroidal growth. Improved reflection of the transcriptional activity related to proliferation, hypoxia, and differentiation in EwS patient tumors was detected in EwS cells grown in this refined in vitro condition. Moreover, transcriptional signatures associated with the oncogenic activity of the EwS-specific FET::ETS fusion transcription factors in the refined culture condition were shifted from proliferative toward metabolic gene signatures. The herein-presented EwS cell culture technique with increased physiological relevance provides a broadly applicable approach for enhanced in vitro modeling relevant to advancing EwS research and the validity of experimental results. Show less

The aim of the UniProt Knowledgebase (UniProtKB; https://www.uniprot.org/) is to provide users with a comprehensive, high-quality and freely accessible set of protein sequences annotated with functional information. In this publication, we describe ongoing changes to our production pipeline to limit the sequences available in UniProtKB to high-quality, non-redundant reference proteomes. We continue to manually curate the scientific literature to add the latest functional data and use machine learning techniques. We also encourage community curation to ensure key publications are not missed. We provide an update on the automatic annotation methods used by UniProtKB to predict information for unreviewed entries describing unstudied proteins. Finally, updates to the UniProt website are described, including a new tab linking protein to genomic information. In recognition of its value to the scientific community, the UniProt database has been awarded Global Core Biodata Resource status. Show less

Title: Small upconversion-ruthenium nanohybrids for cancer theranostics. Abstract: Photoresponsive drug delivery systems have great potential for improved cancer therapy. However, most of the currently available drug-delivery nanosystems are relatively large and require light excitation with low tissue penetration. Here, we designed a near infrared responsive drug delivery system by loading [Ru(terpyridine)(dipyridophenazine)(H2O)]2+ (Ru(tpy)DPPZ) in azobenzene-modified mesoporous silica coated NaGdF4:Nd0.01/Yb0.2/Tm0.01 upconversion nanoparticles (azo-mSiO2-UCNPs). Upon 808 nm excitation, the generated ultraviolet and blue upconversion luminescence induced a reversible cis-trans isomerization of azobenzene for on-demand release of Ru(tpy)DPPZ. Imaging of both the UCNPs and Ru(tpy)DPPZ revealed targeted drug delivery to the nucleus of MCF-7 breast cancer cells, inducing DNA damage and concomitant cell destruction. Considering that cell nuclei are the core of cellular transcription and the main site of action for multiple chemotherapeutic drugs, our NIR-excitable and small (10 nm diameter) nanohybrids can potentially become highly versatile tools for targeted cancer theranostics. Show less

Title: The role of ancillary ligands on benzodipyridophenazine-based Ru(II)/Ir(III) complexes in dark and light toxicity against TNBC cells. Abstract: In this study, we investigated the impact of ancillary ligands on the anticancer activity of benzodipyridophenazine-based Ru(II) and Ir(III) complexes (Ru1, Ru2, Ir1, and Ir2). These metal complexes displayed three significant absorption bands attributed to the ligand-centered (LC) transitions, ligand-to-ligand charge transfer (LLCT), and metal-to-ligand charge transfer (MLCT). Binding studies of biomolecules were performed with the complexes along with the ligand, and it was found that after binding with Ru(II)/Ir(III), the properties of the ligands were enhanced. In vitro screening revealed that complex [(η5-Cp*)IrIIICl(κ2-N,N-benzo[i]dipyrido[3,2-a:2',3'-c])phenazine] (Ir1) exhibited the highest potency and selectivity (IC50 ∼ 2.14 μM, PI > 13) under yellow light irradiation. The photo-toxicity trend was Ir1 > Ru1 > Ir2 ≫ Ru2, which was found to be directly correlated with the singlet oxygen quantum yield (1O2). Chloro-substituted complexes (Ir1 and Ru1) were effective for hypoxic tumor treatment, particularly Ir1, which could generate high amounts of reactive oxygen species (ROS, type I PDT) in cells under photo irradiation. The high value of fluorescence quantum yield (fφ = 0.26) and significant emission at λ = 571 nm of Ir1 were certainly useful for bio-imaging applications. Colocalisation and DCFDA studies of Ir1 revealed that it can accumulate in the mitochondria, leading to depolarization of the mitochondrial membrane. These studies confirm that the complex Ir1 is a promising candidate for TNBC treatment in hypoxic tumors, with efficacy comparable to the current PDT drug Photofrin. Show less

In order to discover new dual-active agents, novel ruthenium (η⁶-p-cymene) complexes of the general formula [(η⁶-p-cym)Ru(OO)Cl] with O,O-diketo ester ligands ethyl 2-hydroxy-4-aryl-4-oxobut-2-enoate (1-3), were synthesized. The complexes 1-3 were characterized by spectral techniques (UV-Vis, IR, ¹H and ¹³C NMR, and ESI-HRMS), elemental analysis, and X-ray crystallography. Based on in vitro DNA/HSA experiments, complex 1 exhibited the highest DNA/HSA-activity, suggesting that the presence of an alkene chain contributes to increased activity. The cytotoxic activity of 1-3 was evaluated in a panel of human cancer cell lines (A549, MDA-MB-231, LS-174, HeLa), and in one normal cell line (MRC-5), both in the absence and presence of biocompatible ionic liquids (BIO-ILs) such as cholinium glycinate (Cho-Gly), cholinium β-alaninate (Cho-Ala), and cholinium glutamate (Cho-Glu). Complex 1 exhibited the highest cytotoxicity and demonstrated selectivity toward HeLa cells. Additionally, its cytotoxicity was enhanced when combined with the BIO-ILs Cho-Gly and Cho-Ala. This study suggests that ionic liquids can influence the efficacy and selectivity of cancer treatments, highlighting the potential for enhancing therapeutic outcomes. However, it also emphasizes the need for a deeper understanding of BIO-IL interactions with cellular processes. Furthermore, compound 1 displayed strong antimicrobial activity against Staphylococcus aureus and Escherichia coli (MIC = 0.078 mg/mL). Among the assessed species, Candida albicans showed the highest sensitivity to antifungal activity. These results suggest that investigated compounds may have potential for further development as clinical candidates, pending additional studies. Show less

Title: Necrosis inducing tetranuclear Ru(II)-Re(I) metal complex for anticancer therapy. Abstract: Chemotherapy is one of the most widely used anticancer treatments worldwide. However, despite its clinical effectiveness, most chemotherapeutic agents are associated with severe side effects. To address this limitation, there is an urgent need for the development of novel anticancer agents. Among the promising alternatives, Ruthenium and Rhenium complexes have garnered significant attention in the scientific literature. This study proposes combining these two metal moieties into a single tetranuclear complex, bridged by a 2,2'-bipyrimidine ligand. Cytotoxicity tests revealed broad activity of the novel metal complex against multiple cancer cell lines. Mechanistic studies suggested that the complex induces cell death by necrosis. Further analyses demonstrated its ability to eradicate colon carcinoma tumor spheroids at micromolar concentrations. To the best of our knowledge, this represents the first example of a Ru(II)-Re(I) tetranuclear metal complex as an anticancer agent. Show less

Title: Highly effective Ru(II) and Os(II) half-sandwich complexes induce cytotoxicity in cancer cells through combined mitochondrial and endoplasmic reticulum stress. Abstract: A series of ruthenium(II) and osmium(II) half-sandwich complexes was synthesized and characterized for its potential as a new class of anticancer agents. The complexes feature polycyclic aromatic hydrocarbon (PAH)-substituted Schiff bases and were rationally designed to combine the redox-modulating MoA of half-sandwich Ru, Rh, Os and Ir complexes, connected with their ability to induce the formation of various reactive oxygen species (ROS), with the ability of PAH-substituents to target and disrupt DNA. The complexes [Ru(η6-pcym)Cl(L)]PF6 (1-4) and [Os(η6-pcym)Cl(L)]PF6 (5-8) were stable in aqueous environments, in contrast to the rapid degradation observed for the co-studied rhodium(III) (9-12) and iridium(III) (13-16) [M(η5-Cp∗)Cl(L)]PF6 complexes; L = ethane-1,2-diamine-based Schiff bases (L1-L4) bearing two terminal PAH substituents 2-naphtyl (for L1), 9-anthracenyl (for L2), 9-phenanthrenyl (L3) or 1-pyrenyl (L4); pcym = 1-methyl-4-(propan-2-yl)benzene (p-cymene), Cp∗ = pentamethylcyclopentadienyl. Biological testing demonstrated that 1-8 possess significant antiproliferative activity against various lung cancer cell lines, including those resistant to cisplatin, with Os(II) complex 5 showing the highest cytotoxicity. Treatment with these complexes led to the activation of stress-related gene pathways, including unconventional endoplasmic reticulum stress, apoptotic signalling, and mitochondrial membrane depolarization. Activation of p21/GADD45A pathway indicates DNA-damage response, as well. Notably, these complexes did not induce significant inflammatory responses, a notable advantage over cisplatin. The results highlight the potential of Ru and Os half-sandwich complexes as alternative metallodrugs, capable of overcoming platinum resistance and minimizing inflammatory side effects. This study suggests that these compounds could serve as a promising class of anticancer agents for future clinical development. Show less

Life is an exergonic chemical reaction. The same was true when the very first cells emerged at life's origin. In order to live, all cells need a source of carbon, energy, and electrons to drive their overall reaction network (metabolism). In most cells, these are separate pathways. There is only one biochemical pathway that serves all three needs simultaneously: the acetyl-CoA pathway of CO2 fixation. In the acetyl-CoA pathway, electrons from H2 reduce CO2 to pyruvate for carbon supply, while methane or acetate synthesis are coupled to energy conservation as ATP. This simplicity and thermodynamic favorability prompted Georg Fuchs and Erhard Stupperich to propose in 1985 that the acetyl-CoA pathway might mark the origin of metabolism, at the same time that Steve Ragsdale and Harland Wood were uncovering catalytic roles for Fe, Co, and Ni in the enzymes of the pathway. Subsequent work has provided strong support for those proposals.In the presence of Fe, Co, and Ni in their native metallic state as catalysts, aqueous H2 and CO2 react specifically to formate, acetate, methane, and pyruvate overnight at 100 °C. These metals (and their alloys) thus replace the function of over 120 enzymes required for the conversion of H2 and CO2 to pyruvate via the pathway and its cofactors, an unprecedented set of findings in the study of biochemical evolution. The reactions require alkaline conditions, which promote hydrogen oxidation by proton removal and are naturally generated in serpentinizing (H2-producing) hydrothermal vents. Serpentinizing hydrothermal vents furthermore produce natural deposits of native Fe, Co, Ni, and their alloys. These are precisely the metals that reduce CO2 with H2 in the laboratory; they are also the metals found at the active sites of enzymes in the acetyl-CoA pathway. Iron, cobalt and nickel are relicts of the environments in which metabolism arose, environments that still harbor ancient methane- and acetate-producing autotrophs today. This convergence indicates bedrock-level antiquity for the acetyl-CoA pathway. In acetogens and methanogens growing on H2 as reductant, the acetyl-CoA pathway requires flavin-based electron bifurcation as a source of reduced ferredoxin (a 4Fe4S cluster-containing protein) in order to function. Recent findings show that H2 can reduce the 4Fe4S clusters of ferredoxin in the presence of native iron, uncovering an evolutionary precursor of flavin-based electron bifurcation and suggesting an origin of FeS-dependent electron transfer in proteins. Traditionally discussed as catalysts in early evolution, the most common function of FeS clusters in metabolism is one-electron transfer, also in radical SAM enzymes, a large and ancient enzyme family. The cofactors and active sites in enzymes of the acetyl-CoA pathway uncover chemical antiquity in metabolism involving metals, methyl groups, methyl transfer reactions, cobamides, pterins, GTP, S-adenosylmethionine, radical SAM enzymes, and carbon-metal bonds. The reaction sequence from H2 and CO2 to pyruvate on naturally deposited native metals is maximally simple. It requires neither nitrogen, sulfur, phosphorus, RNA, ion gradients, nor light. Solid-state metal catalysts tether the origin of metabolism to a H2-producing, serpentinizing hydrothermal vent. Show less

Expert curation is essential to capture knowledge of enzyme functions from the scientific literature in FAIR open knowledgebases but cannot keep pace with the rate of new discoveries and new publications. In this work we present EnzChemRED, for Enzyme Chemistry Relation Extraction Dataset, a new training and benchmarking dataset to support the development of Natural Language Processing (NLP) methods such as (large) language models that can assist enzyme curation. EnzChemRED consists of 1,210 expert curated PubMed abstracts where enzymes and the chemical reactions they catalyze are annotated using identifiers from the protein knowledgebase UniProtKB and the chemical ontology ChEBI. We show that fine-tuning language models with EnzChemRED significantly boosts their ability to identify proteins and chemicals in text (86.30% F1 score) and to extract the chemical conversions (86.66% F1 score) and the enzymes that catalyze those conversions (83.79% F1 score). We apply our methods to abstracts at PubMed scale to create a draft map of enzyme functions in literature to guide curation efforts in UniProtKB and the reaction knowledgebase Rhea. Show less

In the era of high throughput sequencing, special software is required for the clinical evaluation of genetic variants. We developed REEV (Review, Evaluate and Explain Variants), a user-friendly platform for clinicians and researchers in the field of rare disease genetics. Supporting data was aggregated from public data sources. We compared REEV with seven other tools for clinical variant evaluation. REEV (semi-)automatically fills individual ACMG criteria facilitating variant interpretation. REEV can store disease and phenotype data related to a case to use these for phenotype similarity measures. Users can create public permanent links for individual variants that can be saved as browser bookmarks and shared. REEV may help in the fast diagnostic assessment of genetic variants in a clinical as well as in a research context. REEV (https://reev.bihealth.org/) is free and open to all users and there is no login requirement. Show less

Thousands of genomes are publicly available, however, most genes in those genomes have poorly defined functions. This is partly due to a gap between previously published, experimentally characterized protein activities and activities deposited in databases. This activity deposition is bottlenecked by the time-consuming biocuration process. The emergence of large language models presents an opportunity to speed up the text-mining of protein activities for biocuration. Show less

Title: Rational design of a red-light absorbing ruthenium polypyridine complex as a photosensitizer for photodynamic therapy. Abstract: Herein, the computer-guided design, chemical synthesis, and biological evaluation of a RuC polypyridine complex, that could eradicate cancerous cells upon excitation with red light at 630 nm, is reported. Show less

Liver cancer is one of the leading causes of death that motivating scientists worldwide to synthesize novel chemotherapeutics. Ru(II)-polypyridyl complexes are extensively studied for possible therapeutic and cellular applications due to their tunable coordination chemistry, structural diversity, ligand-exchange kinetics, accessible redox states, and rich photophysical or photochemical properties. Herein, we have synthesized a series of Ru(II) polypyridyl complexes [Ru^II(N^N)₂(ox)] (1-3), where ox is oxalate (C₂O₄^2-) and N^N is 1,10-phenanthroline (phen) (1), dipyrido[3,2-d:2',3'-f]quinoxaline (dpq) (2), and dipyrido[3,2,-a:2',3'-c]phenazine (dppz) (3). Oxalate (ox^2-) was opted as a bioactive dioxo ligand to prevent facile hydrolysis in aqueous media, thereby increasing the stability of the Ru(II)-polypyridyl complexes in physiological media. We thoroughly characterized all the complexes using ESI-MS, FT-IR, UV-vis, and ¹H NMR spectroscopy and other physicochemical methods. The complexes were stable under physiological conditions and under low-energy green LED light (λ_irr = 530 nm). However, the photoirradiation of complexes resulted in the efficient generation of singlet oxygen (¹O₂) as a major reactive oxygen species (ROS). The role of the extended aromatic conjugation of the N^N-donor ligands in the complexes was demonstrated by their binding propensities with CT-DNA and bovine serum albumin (BSA). Both DNA intercalation and groove binding were evidenced, while tryptophan (Trp) and tyrosine (Tyr) binding site preferences were revealed from the synchronous fluorescence spectra (SFS) of BSA. The cytotoxic profiling of the complexes performed on hepatocellular carcinoma cells (HepG2) in the dark and in the presence of green light indicated their dose-dependent cytotoxicity. The [Ru^II(N^N)₂(ox)] complexes exhibited enhanced photocytotoxicity mediated by efficient generation of cytotoxic ¹O₂ and effective interaction with DNA. All the complexes were internalized by the HepG2 liver cancer cells efficiently and localized to the cytoplasm and nucleus. The complexes exhibited potent anti-proliferative, anti-clonogenic, and anti-migratory effects on the cancer cells, suggesting their potential for therapeutic applications. Show less

Title: Insights into Mechanisms and Promising Triple Negative Breast Cancer Therapeutic Potential for a Water-Soluble Ruthenium Compound. Abstract: Triple negative breast cancer (TNBC) represents a subtype of breast cancer that does not express the three major prognostic receptors of human epidermal growth factor receptor 2 (HER2), progesterone (PR), and estrogen (ER). This limits treatment options and results in a high rate of mortality. We have reported previously on the efficacy of a water-soluble, cationic organometallic compound (Ru-IM) in a TNBC mouse xenograft model with impressive tumor reduction and targeted tumor drug accumulation. Ru-IM inhibits cancer hallmarks such as migration, angiogenesis, and invasion in TNBC cells by a mechanism that generates apoptotic cell death. Ru-IM displays little interaction with DNA and appears to act by a P53-independent pathway. We report here on the mitochondrial alterations caused by Ru-IM treatment and detail the inhibitory properties of Ru-IM in the PI3K/AKT/mTOR pathway in MDA-MB-231 cells. Lastly, we describe the results of an efficacy study of the TNBC xenografted mouse model with Ru-IM and Olaparib monotherapy and combinatory treatments. We find 59% tumor shrinkage with Ru-IM and 65% with the combination. Histopathological analysis confirmed no test-article-related toxicity. Immunohistochemical analysis indicated an inhibition of the angiogenic marker CD31 and increased levels of apoptotic cleaved caspase 3 marker, along with a slight inhibition of p-mTOR. Taken together, the effects of Ru-IM in vitro show similar trends and translation in vivo. Our investigation underscores the therapeutic potential of Ru-IM in addressing the challenges posed by TNBC as evidenced by its robust efficacy in inhibiting key cancer hallmarks, substantial tumor reduction, and minimal systemic toxicity. Show less

Organometallic complexes of the formula [Ru(N^N)(p-cymene)Cl][X] (N^N = bidentate polypyridyl ligands, p-cymene = 1-methyl-4-(1-methylethyl)-benzene, X = counter anion), are currently studied as possible candidates for the potential treatment of cancer. Searching for new organometallic compounds with good to moderate cytotoxic activities, a series of mononuclear water-soluble ruthenium(II)-arene complexes incorporating substituted pyridine-quinoline ligands, with pending -CH₂OH, -CO₂H and -CO₂Me groups in the 4-position of quinoline ring, were synthesized, for the first time, to study their possible effect to modulate the activity of the ruthenium p-cymene complexes. These include the [Ru(η⁶-p-cymene)(pqhyme)Cl][X] (X = Cl^- (1-Cl), PF₆^- (1-PF₆), pqhyme = 4-hydroxymethyl-2-(pyridin-2-yl)quinoline), [Ru(η⁶-p-cymene)(pqca)Cl][Cl] ((2-Cl), pqca = 4-carboxy-2-(pyridin-2-yl)quinoline), and [Ru(η⁶-p-cymene)(pqcame)Cl][X] (X = Cl^- (3-Cl), PF₆^- (3-PF₆), pqcame = 4-carboxymethyl-2-(pyridin-2-yl)quinoline) complexes, respectively. Identification of the complexes was based on multinuclear NMR and ATR-IR spectroscopic methods, elemental analysis, conductivity measurements, UV-Vis spectroscopic, and ESI-HRMS techniques. The solid-state structures of 1-PF₆ and 3-PF₆ have been elucidated by single-crystal X-ray diffraction revealing a three-legged piano stool geometry. This is the first time that the in vitro cytotoxic activities of these complexes are studied. These were conducted in HEK293T (human embryonic kidney cells) and HeLa cells (cervical cancer cells) via the MTT assay. The results show poor in vitro anticancer activities for the HeLa cancer cell lines and 3-Cl proved to be the most potent (IC₅₀ > 80 μΜ). In both cell lines, the cytotoxicity of the ligand precursor pqhyme is significantly higher than that of cisplatin. Show less

Title: Cyrene™ as a green alternative to Abstract: Ruthenium(II) polypyridyl complexes (RPCs) that emit from triplet metal-to-ligand charge transfer (MLCT) states find a wide variety of uses ranging from luminophores to potential anti-cancer or anti-bacterial therapeutics. Herein we describe a greener, microwave-assisted synthetic pathway for the preparation of homoleptic [Ru(N^N)3]2+ and bis-heteroleptic [Ru(N^N)2(N'^N')]2+ type complexes. This employs the bio-renewable solvent Cyrene™, dihydrolevoglucosenone, as a green alternative to N,N'-dimethylformamide (DMF) in the synthesis of Ru(N^N)2Cl2 intermediate complexes, obtaining comparable yields for N^N = 2,2'-bipyridine, 1,10-phenanthroline and methylated derivatives. Employing these intermediates, a range of RPCs were prepared and we verify that the ubiquitous luminophore [Ru(bpy)3]2+ (bpy = 2,2'-bipyridine) can be prepared by this two-step green pathway where it is virtually indistinguishable from a commercial reference. Furthermore, the novel complexes [Ru(bpy)2(10,11-dmdppz)]2+ (10,11-dmdppz = 10,11-dimethyl-dipyridophenazine) and [Ru(5,5'-dmbpy)2(10,11-dmdppz)]2+ (5,5'-dmbpy = 5,5'-dimethyl-bpy) intercalate duplex DNA with high affinity (DNA binding constants, Kb = 5.7 × 107 and 1.0 × 107 M-1, respectively) and function as plasma membrane and nuclear DNA dyes for confocal and STED microscopies courtesy of their long-lived MLCT luminescence. Show less

Transition metal complexes with characteristics of unique packaging in nanoparticles and remarkable cancer cell cytotoxicity have emerged as potential alternatives to platinum-based antitumor drugs. Here we report the synthesis, characterization, and antitumor activities of three new Ruthenium complexes that introduce 5-fluorouracil-derived ligands. Notably, encapsulation of one such metal complex, Ru3, within pluronic^® F-127 micelles (Ru3-M) significantly enhanced Ru3 cytotoxicity toward A549 cells by a factor of four. To determine the mechanisms underlying Ru3-M cytotoxicity, additional in vitro experiments were conducted that revealed A549 cell treatment with lysosome-targeting Ru3-M triggered oxidative stress, induced mitochondrial membrane potential depolarization, and drastically reduced intracellular ATP levels. Taken together, these results demonstrated that Ru3-M killed cells mainly via a non-apoptotic pathway known as oncosis, as evidenced by observed Ru3-M-induced cellular morphological changes including cytosolic flushing, cell swelling, and cytoplasmic vacuolation. In turn, these changes together caused cytoskeletal collapse and activation of porimin and calpain1 proteins with known oncotic functions that distinguished this oncotic process from other cell death processes. In summary, Ru3-M is a potential anticancer agent that kills A549 cells via a novel mechanism involving Ru(II) complex triggering of cell death via oncosis. Show less

Herein, we describe and investigate biological activity of three octahedral ruthenium(II) complexes of the type [Ru(C^∧N)(phen)₂]⁺, RuL1-RuL3, containing a π-expansive cyclometalating substituted benzo[g]quinoxaline ligand (C^∧N ligand) (phen = 1,10-phenanthroline). Compounds RuL1-RuL3 in cervical, melanoma, and colon human cancer cells exhibit high phototoxicity after irradiation with light (particularly blue), with the phototoxicity index reaching 100 for the complex RuL2 in most sensitive HCT116 cells. RuL2 accumulates in the cellular membranes. If irradiated, it induces lipid peroxidation, likely connected with photoinduced ROS generation. Oxidative damage to the fatty acids leads to the attenuation of the membranes, the activation of caspase 3, and the triggering of the apoptotic pathway, thus implementing membrane-localized photodynamic therapy. RuL2 is the first photoactive ruthenium-based complex capable of killing the hardly treatable colon cancer stem cells, a highly resilient subpopulation within a heterogeneous tumor mass, responsible for tumor recurrence and the metastatic progression of cancer. Show less

Treatments of N-(1H-benzo[d]imidazol-2-yl)pyrazine-2-carboxamide (HL₁) and N-(benzo[d]thiazol-2-yl)pyrazine-2-carboxamide carboxamide ligands (HL₂) with [Ru(p-cymene)Cl₂]₂ and [Ru(PPh₃)₃Cl₂] precursors afforded the respective Ru(ii) complexes [Ru(L₁)(p-cymene)Cl] (Ru1), [Ru(L₂)(p-cymene)Cl] (Ru2), [Ru(L₁)(PPh₃)₂Cl] (Ru3), and [Ru(L₂)(PPh₃)₂Cl] (Ru4). These complexes were characterized by NMR, FT-IR spectroscopies, mass spectrometry, elemental analyses, and crystal X-ray crystallography for Ru2. The molecular structure of complex Ru2 contains one mono-anionic bidentate bound ligand and display pseudo-octahedral piano stool geometry around the Ru(ii) atom. The interactions with calf thymus DNA (CT-DNA) and bovine serum albumin (BSA) were investigated by spectroscopic techniques. The experimental binding studies suggest that complexes Ru1-Ru4 interact with DNA, primarily through minor groove binding, as supported by molecular docking results. Additionally, these complexes exhibit strong quenching of the fluorescence of tryptophan residues in BSA, displaying static quenching. The in vitro cytotoxicity studies of compounds Ru1-Ru4 were assessed in cancer cell lines (A549, PC-3, HT-29, Caco-2, and HeLa), as well as a non-cancer line (KMST-6). Compounds Ru1 and Ru2 exhibited superior cytotoxicity compared to Ru3 and Ru4. The in vitro cytotoxicity and selectivity of compounds Ru1 and Ru2 against A549, PC-3, and Caco-2 cell lines surpassed that of cisplatin. Show less

Colon cancer is one of the most commonly diagnosed cancers and is recognized as the most aggressive tumor of the digestive system. Aberrant activation of signal transducer and activator of transcription 3 (STAT3) is associated with proliferation, metastasis and immunosuppression of the tumor cells. Here, to inhibit the STAT3 pathway and suppress metastasis in colon cancer cells, the half-sandwich iridium complex Ir-ART containing an artesunate-derived ligand was synthesized. The complex showed remarkable antiproliferative activity against human colon cancer HCT-116 cells and exhibited a concentration-dependent reduction in STAT3 protein expression. Mechanism study demonstrates that Ir-ART is located mainly in the nucleus and mitochondria, causing γ-H2AX and cyclin B1 reduction and reactive oxygen species accumulation and mitochondrial membrane potential loss, ultimately leading to autophagic cell death. The migration of cancer cells was also inhibited via metalloproteinase 9 downregulation. Furthermore, Ir-ART could initiate antitumor immune responses by eliciting immunogenic cell death and downregulating immunosuppressive cytokine cyclooxygenase-2. Taken together, Ir-ART is expected to be further applied to chemotherapy and immunotherapy for colon cancer. Show less

Title: Endocytic Uptake of Self-Assembled Iridium(III) Nanoaggregates for Holistic Treatment of Metastatic 3D Triple-Negative Breast Tumor Spheroids. Abstract: Triple-negative breast cancer (TNBC) presents a formidable challenge due to its aggressive behavior and limited array of treatment options available. This study focuses on employing nanoaggregate material of organometallic Ir(III) complexes for treating TNBC cell line MDA-MB-231. In this approach, Ir(III) complexes with enhanced cellular permeability are strategically designed and achieved through the incorporation of COOMe groups into their structure. The lead compound, IrL1, exhibits promiscuous nanoscale aggregation in RPMI cell culture media, characterized by a stable hydrodynamic effective diameter ranging from 190 to 202 nm over 48 h. With excellent photo-responsive contrast-enhanced cell imaging properties IrL1 exhibits an outstanding IC50, 48h value of 36.05± 0.03 nm when irradiated with 390 nm light in MDA-MB-231 (IC50, 48 h of Cisplatin is 5.29 µµ). In cell, investigation confirms that IrL1 nanoaggregates internalization via energy-dependent endocytosis undergo ferroptosis and ROS mediated cell death in MDA-MB-231 cells. Further, these in vivo studies using NOD-SCID mice confirmed that IrL1 exhibits a tendency to ablate tumors inoculated in mice models at therapeutically relevant doses. Thus, this comprehensive approach holds promise for expanding the repertoire of organometallic Ir(III) nanoaggregates with adaptable characteristics, thereby advancing their clinical utility of nanomedicine in the holistic treatment of metastatic 3D triple-negative breast tumor spheroids. Show less

A series of rhenium(I) complexes of the type fac-[Re(CO)₃(N^N)L]^0/+, Re1-Re9, was synthesized, where N^N = benzimidazole-derived bidentate ligand with an ester functionality and L = chloride or pyridine-type ligand. The new compounds demonstrated potent activity toward ovarian A2780 cancer cells. The most active complexes, Re7-Re9, incorporating 4-NMe₂py, exhibited remarkable activity in 3D HeLa spheroids. The emission in the red region of Re9, which contains an electron-deficient benzothiazole moiety, allowed its operability as a bioimaging tool for in vitro and in vivo visualization. Re9 effectivity was tested in two different C. elegans tumoral strains, JK1466 and MT2124, to broaden the oncogenic pathways studied. The results showed that Re9 was able to reduce the tumor growth in both strains by increasing the ROS production inside the cells. Moreover, the selectivity of the compound toward cancerous cells was remarkable as it did not affect neither the development nor the progeny of the nematodes. Show less

Title: Enhancing Bioactivity of Abstract: This study investigates the potential of using ionic liquids as cosolvents to enhance the solubility and activity of poorly soluble rhodium(III) complexes, particularly those with diene, pyridine derivatives, and camphor-derived bis-pyrazolylpyridine ligands, in relation to 5'-GMP, CT-DNA, and HSA as well as their biological activity. Findings indicate that ionic liquids significantly increase the substitution activity of these complexes toward 5'-GMP while only marginally affecting DNA/HSA binding affinities with molecular docking, further confirming the experimental results. Lipophilicity assessments indicated good lipophilicity. Notably, cytotoxicity studies show that Rh2 is selectively effective against HeLa cancer cells, with IL1 and IL10 modulating the cytotoxic effects. Redox evaluations indicate that rhodium complexes induce oxidative stress in cancerous cells while maintaining redox balance in noncancerous cells. By elucidating the role of ionic liquids in modulating these effects, the study proposes a promising avenue for augmenting the efficacy and selectivity of cancer treatments, thus opening new horizons in cancer therapeutics. Show less