👤 Zhou D

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

Psychiatric diseases are often treated with several drugs. In addition, the risk of developing somatic comorbidities which may require drug therapy is higher in patients with than in patients without psychiatric diseases. Further on, the risk of drug-drug interactions (DDI) increases with the number of drugs taken. The aim of this study was to analyze whether already known DDI between psychiatric drugs and somatic medications still occur in everyday clinical practice. Show less

Deep learning, a cornerstone of artificial intelligence, is driving rapid advancements in computational biology. Protein-protein interactions (PPIs) are fundamental regulators of biological functions. With the inclusion of deep learning in PPI research, the field is undergoing transformative changes. Therefore, there is an urgent need for a comprehensive review and assessment of recent developments to improve analytical methods and open up a wider range of biomedical applications. This review meticulously assesses deep learning progress in PPI prediction from 2021 to 2025. We evaluate core architectures (GNNs, CNNs, RNNs) and pioneering approaches-attention-driven Transformers, multi-task frameworks, multimodal integration of sequence and structural data, transfer learning via BERT and ESM, and autoencoders for interaction characterization. Moreover, we examined enhanced algorithms for dealing with data imbalances, variations, and high-dimensional feature sparsity, as well as industry challenges (including shifting protein interactions, interactions with non-model organisms, and rare or unannotated protein interactions), and offered perspectives on the future of the field. In summary, this review systematically summarizes the latest advances and existing challenges in deep learning in the field of protein interaction analysis, providing a valuable reference for researchers in the fields of computational biology and deep learning. Show less

Small redox active molecules such as reactive nitrogen and oxygen species and hydrogen sulfide have emerged as important biological mediators that are involved in various physiological and pathophysiological processes. Advancement in understanding of cellular mechanisms that tightly regulate both generation and reactivity of these molecules is central to improved management of various disease states including cancer and cardiovascular dysfunction. Imbalance in the production of redox active molecules can lead to damage of critical cellular components such as cell membranes, proteins and DNA and thus may trigger the onset of disease. These small inorganic molecules react independently as well as in a concerted manner to mediate physiological responses. This review provides a general overview of the redox biology of these key molecules, their diverse chemistry relevant to physiological processes and their interrelated nature in cellular signaling. Show less

Reactive molecules, including oxygen and nitrogen species, serve dual roles in human physiology. While they function as essential signaling molecules under normal physiological conditions, they contribute to cellular dysfunction and damage when produced in excess by normal metabolism or in response to stressors. Oxidative/nitrosative stress is a pathological state, resulting from the overproduction of reactive species exceeding the antioxidant capacity of the body, which is implicated in several chronic human diseases. Antioxidant therapies aimed at restoring redox balance and preventing oxidative/nitrosative stress have demonstrated efficacy in preclinical models. However, their clinical applications have met with inconsistent success owing to efficacy, safety, and bioavailability concerns. This summative review analyzes the role of reactive species in human pathophysiology, the mechanisms of action of antioxidant protection, and the challenges that hinder their translation into effective clinical therapies in order to evaluate potential emerging strategies such as targeted delivery systems, precision medicine, and synergistic therapeutic approaches, among others, to overcome current limitations. By integrating recent advances, this review highlights the value of targeting reactive species in the prevention and management of chronic diseases. Show less

As two pivotal regulatory factors in cancer biology, oxidative stress and inflammation interact dynamically through complex network mechanisms to influence tumor initiation, progression, and treatment resistance. Oxidative stress induces genomic instability, oncogenic signaling activation, and tumor microenvironment (TME) remodeling via the abnormal accumulation of reactive oxygen species (ROS) or reactive nitrogen species (RNS). Conversely, inflammation sustains malignant phenotypes by releasing pro-inflammatory cytokines and chemokines and promoting immune cell infiltration. These processes create a vicious cycle via positive feedback loops whereby oxidative stress initiates inflammatory signaling, while the inflammatory milieu further amplifies ROS/RNS production, collectively promoting proliferation, migration, angiogenesis, drug resistance, and immune evasion in tumor cells. Moreover, their crosstalk modulates DNA damage repair, metabolic reprogramming, and drug efflux pump activity, significantly impacting the sensitivity of cancer cells to chemotherapy, radiotherapy, and targeted therapies. This review systematically discusses these advances and the molecular mechanisms underlying the interplay between oxidative stress and inflammation in cancer biology. It also explores their potential as diagnostic biomarkers and prognostic indicators and highlights novel therapeutic strategies targeting the oxidative stress-inflammation axis. The goal is to provide a theoretical framework and translational roadmap for developing synergistic anti-tumor therapies. 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

Colorectal cancer (CRC) remains a significant global health challenge, ranking third in incidence and second in mortality among cancers worldwide. This review addresses the complex landscape of CRC, focusing on incidence, mortality trends, preventive strategies, and the evolving therapeutic approaches, particularly highlighting the role of platinum-based drugs like oxaliplatin (OXP). It also underscores the increasing burden of CRC, with factors such as westernized diets, aging populations, and genetic predispositions contributing to its prevalence. Therapeutically, early detection greatly enhances survival rates, emphasizing the importance of regular colonoscopies and stool tests. For advanced CRC, chemotherapy remains pivotal, with OXP as a cornerstone treatment despite its associated chemotherapy-induced peripheral neurotoxicity (CIPN). The review explores innovative strategies to overcome challenges related to chemotherapy, such as drug resistance and side effects, highlighting recent developments in the field, such as Pt(IV) prodrugs and immunotherapeutic approaches to enhance efficacy while minimizing toxicity. Additionally, this manuscript examines experimental models for drug screening, emphasizing the role of murine models and advanced 3D in vitro systems in CRC research. Overall, the review advocates for a comprehensive approach, integrating prevention, early detection, and personalized treatments to alleviate the global burden of CRC. 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

Lung cancer is most terrible cause of cancer-related death throughout the world. This study focused on the synthesis and characterisation of novel flavokawain A ruthenium-p-cymene complex and to investigate the chemotherapeutic activity against lung carcinoma via in silico, in vitro and in vivo approaches. The complex was characterised via several spectroscopic techniques. In vitro study including cell viability, transwell migration, Western blot and flow cytometric analysis have been executed on both A549 and NCI-H460 cells. The toxicological assessment was performed and subsequently anticancer activity of complex was evaluated in benzo[α]pyrene persuaded lung carcinoma in mice. The molecular docking study demonstrated the compound has greater binding ability with β-catenin, Akt, HER2 and PARP. Followed by the complex treatment, the downregulation of β-catenin, PI3K, Akt, HER2 and PARP were investigated by Western blot analysis and cell cycle arrest was determined through flow cytometry. The outcomes of in vivo experimentation represented fruitful restoration of typical lung architecture after complex treatment. Immunohistochemical analysis demonstrated the downstream of β-catenin/m-TOR/Akt and upstream of caspase-3 and p53 expression, thereby initiating apoptosis. The complex exhibited a potent chemotherapeutic activity via the alteration of tumour microenvironment by modulating PI3K/Akt/β-catenin/HER2/PARP transduction in correlates with apoptotic events in lung carcinoma. Show less

Hypoxia, a hallmark of many solid tumors, is linked to increased cancer aggressiveness, metastasis, and resistance to conventional therapies, leading to poor patient outcomes. This challenges the efficiency of photodynamic therapy (PDT), which relies on the generation of cytotoxic reactive oxygen species (ROS) through the irradiation of a photosensitizer (PS), a process partially dependent on oxygen levels. In this work, we introduce a novel family of potent PSs based on ruthenium(II) polypyridyl complexes with 2,2'-bipyridyl ligands derived from COUPY coumarins, termed COUBPYs. Ru-COUBPY complexes exhibit outstanding in vitro cytotoxicity against CT-26 cancer cells when irradiated with light within the phototherapeutic window, achieving nanomolar potency in both normoxic and hypoxic conditions while remaining nontoxic in the dark, leading to impressive phototoxic indices (>30,000). Their ability to generate both Type I and Type II ROS underpins their exceptional PDT efficiency. The lead compound of this study, SCV49, shows a favorable in vivo pharmacokinetic profile, excellent toxicological tolerability, and potent tumor growth inhibition in mice bearing subcutaneous CT-26 tumors at doses as low as 3 mg/kg upon irradiation with deep-red light (660 nm). These results allow us to propose SCV49 as a strong candidate for further preclinical development, particularly for treating large hypoxic solid tumors. Show less

Title: Novel Ru(II) Complexes as Type-I/-II Photosensitizers for Multimodal Hypoxia-Tolerant Chemo-Photodynamic/Immune Therapy. Abstract: Photodynamic therapy (PDT) is increasingly regarded as an attractive approach for cancer treatment due to its advantages of low invasiveness, minimal side effects, and high efficiency. Here, two novel Ru(II) complexes 8a,b were designed and synthesized by coordinating phenanthroline and biquinoline ligands with Ru(II) center, and their chemo-photodynamic therapy and immunotherapy were explored. Both 8a and 8b exhibited significant phototoxicity against A549 and 4T1 tumor cells via type-I/-II PDT. Among them, 8b exhibited superior oxygen-independent antitumor effects (IC50s = 1.50-1.76 μM) upon laser irradiation, and displayed micromolar-level chemotherapeutic activities, indicating its potential for chemo/photodynamic dual effects. Furthermore, 8b also initiated an ICD cascade, enhancing recruitment and maturation of antigen-presenting cells, thus triggering a CD8+ T cell antitumor immune response. Finally, in vivo antitumor experiments demonstrated that 8b exhibited significant inhibition of lung and breast tumor growth, with inhibition rates of 94.6% and 97.3%, respectively. Therefore, the Ru(II) complexes we designed, as effective type-I/-II photosensitizers and potential immunoactivators, demonstrate multiple antitumor mechanisms, warranting further study. Show less

Two new Ru(II) complexes, mononuclear [RuCl₂(η⁶-p-cymene)(3,4-dmph-κN)] (1) and the binuclear complex [{RuCl(η⁶-p-cymene)}₂(μ-Cl)(μ-3,4-dmph-κ²N,N')]Cl (2; 3,4-dmph = 3,4-dimethylphenylhydrazine), are synthesized and experimentally and theoretically structurally characterized utilizing ¹H and ¹³C NMR and FTIR spectroscopy, as well as DFT calculations. Degradation product of 2, thus ([{RuCl(η⁶-p-cymene)}₂(μ-Cl)(μ-3,4-dmph-κ²N,N')][RuCl₃(η⁶-p-cymene)] (2b) was characterized with SC-XRD. In the crystals of 2b, the cationic and anionic parts interact through N-H^...Cl hydrogen bridges. The spectrofluorimetric measurements proved the spontaneity of the binding processes of both complexes and HSA. Spin probing EPR measurements implied that 1 and 2 decreased the amount of bound 16-doxylstearate and implicated their potential to bind to HSA more strongly than the spin probe. The cytotoxicity assessment of both complexes against the MDA-MB-231 and MIA PaCa-2 cancer cell lines demonstrated a clear dose-dependent decrease in cell viability and no effect on healthy HS-5 cells. Determination of the malondialdehyde and protein carbonyl concentrations indicated that new complexes could offer protective antioxidant benefits in specific cancer contexts. Gel electrophoresis measurements showed the reduction in MMP9 activity and indicated the potential of 1 in limiting the cancer cells' invasion. The annexin V/PI apoptotic assay results showed that 1 and 2 exhibit different selectivity towards MIA PaCa-2 and MDA-MB-231 cancer cells. A comparative molecular docking analysis of protein binding, specifically targeting acetylcholinesterase (ACHE), matrix metalloproteinase-9 (MMP-9), and human serum albumin (HSA), demonstrated distinct binding interactions for each complex. Show less

While molecular isomers exhibit nearly identical compositions, their spatial arrangement often dictates distinct physicochemical properties. We present a regioisomer engineering strategy to construct two iridium(III) complexes (Ir1 and Ir2) through precise positioning of triphenylamine electron donors relative to the metal chelation core. Compared to Ir1, Ir2 features strategically displaced donors that create a contracted bandgap, reduced oxidation potential, and amplified spin-orbit coupling (SOC). These electronic modifications synergistically enable Ir2 to achieve superior type I photodynamic activity and thus generate O₂^•- and •OH radicals after 633 nm irradiation even under hypoxic conditions. The sustained reactive oxygen species (ROS) production induces potent immunogenic cell death (ICD), ultimately stimulating dendritic cell maturation and antitumor immunity. This regioisomeric design paradigm establishes a molecular blueprint for oxygen-tolerant photosensitizers, addressing the critical challenge of hypoxia in photoimmunotherapy applications. Show less

Ferroptosis, a regulated form of cell death, is intricately linked to iron‑dependent lipid peroxidation. Recent evidence strongly supports the induction of ferroptosis as a promising strategy for treating cancers resistant to conventional therapies. A key player in ferroptosis regulation is ferroptosis suppressor protein 1 (FSP1), which promotes cancer cell resistance by promoting the production of the antioxidant form of coenzyme Q10. Of note, FSP1 confers resistance to ferroptosis independently of the glutathione (GSH) and glutathione peroxidase‑4 pathway. Therefore, targeting FSP1 to weaken its inhibition of ferroptosis may be a viable strategy for treating refractory cancer. This review aims to clarify the molecular mechanisms underlying ferroptosis, the specific pathway by which FSP1 suppresses ferroptosis and the effect of FSP1 inhibitors on cancer cells. 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

Sorafenib, a multiple kinase inhibitor, is widely used as a first-line treatment for hepatocellular carcinoma. However, there is a need for more effective alternatives when sorafenib proves insufficient. In this study, we aimed to design a structure that surpasses sorafenib's efficacy, leading us to synthesize sorafenib-ruthenium complexes for the first time and investigate their properties. Our results indicate that the sorafenib-ruthenium complexes exhibit superior epidermal growth factor receptor (EGFR) inhibition compared to sorafenib alone. Interestingly, among these complexes, Ru3S demonstrated high activity against various cancer cell lines including sorafenib-resistant HepG2 cells while exhibiting significantly lower cytotoxicity than sorafenib in healthy cell lines. Further evaluation of cell cycle, cell apoptosis, and antiangiogenic effects, molecular docking, and molecular dynamics studies revealed that Ru3S holds great potential as a drug candidate. Additionally, when free Ru3S was encapsulated into polymeric micelles M1, enhanced cytotoxicity on HepG2 cells was observed. Collectively, these findings position Ru3S as a promising candidate for EGFR inhibition and warrant further exploration for drug development purposes. Show less

Title: pH-Responsive, Self-Assembled Ruthenium Nanodrug: Dual Impact on Lysosomes and DNA for Synergistic Chemotherapy and Immunogenic Cell Death. Abstract: Several DNA-damaging antitumor agents, including ruthenium complexes, induce immunogenic cell death (ICD). In this study, an arginyl-glycyl-aspartic acid (RGD) peptide-modified carboline ruthenium complex (KS-Ru) is synthesized as a chemotherapeutic nanodrug and an ICD inducer. The RGD peptide, an integrin ligand, provides tumor-specific targeting and promotes self-assembly of the KS-Ru complex. The pH-responsive self-assembly is assessed through transmission and scanning electron microscopy. Additionally, in vitro cytotoxic activity and anti-metastasis ability are evaluated using MTT and Transwell assays, respectively, along with cellular immunofluorescence staining and imaging flow cytometry. The ability of the complex to inhibit primary tumor formation and lung metastasis in vivo is evaluated using Lewis lung cancer and A549 xenograft models. Furthermore, the tumor immune microenvironment is evaluated using single-cell flow mass cytometry. KS-Ru translocates to the nucleus, causing DNA damage and inducing ICD. Within the lysosomes, KS-Ru self-assembled into nanoflowers, leading to lysosomal swelling and apoptosis. Notably, the as-synthesized pH-dependent ruthenium nanomedicine achieves dual functionality-chemotherapy and immunotherapy. Moreover, the pH-responsive self-assembly of KS-Ru enables simultaneous mechanisms in the lysosome and nucleus, thereby lowering the likelihood of drug resistance. This study provides valuable insight for the design of novel ruthenium-based nanoantitumor drugs. Show less

Ruthenium(II) complexes containing diimine ligands have contributed to the development of agents for photoactivated chemotherapy. Several approaches have been used to obtain photolabile Ru(II) complexes. The two most explored have been the use of monodentate ligands and the incorporation of steric effects between the bidentate ligands and the Ru(II). However, the introduction of electronic effects in the ligands has been less explored. Herein, we report a systematic experimental, theoretical, and photocytotoxicity study of a novel series of Ru(II) complexes Ru1-Ru5 of general formula [Ru(phen)₂(N^∧N')]²⁺, where N^∧N' are different minimal strained ligands based on the 1-aryl-4-benzothiazolyl-1,2,3-triazole (BTAT) scaffold, being CH₃ (Ru1), F (Ru2), CF₃ (Ru3), NO₂ (Ru4), and N(CH₃)₂ (Ru5) substituents in the R4 of the phenyl ring. The complexes are stable in solution in the dark, but upon irradiation in water with blue light (λ_ex = 465 nm, 4 mW/cm²) photoejection of the ligand BTAT was observed by HPLC-MS spectrometry and UV-vis spectroscopy, with t_1/2 ranging from 4.5 to 14.15 min depending of the electronic properties of the corresponding BTAT, being Ru4 the less photolabile (the one containing the more electron withdrawing substituent, NO₂). The properties of the ground state singlet and excited state triplet of Ru1-Ru5 have been explored using density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. A mechanism for the photoejection of the BTAT ligand from the Ru complexes, in H₂O, is proposed. Phototoxicity studies in A375 and HeLa human cancer cell lines showed that the new Ru BTAT complexes were strongly phototoxic. An enhancement of the emission intensity of HeLa cells treated with Ru5 was observed in response to increasing doses of light due to the photoejection of the BTAT ligand. These studies suggest that BTAT could serve as a photocleavable protecting group for the cytotoxic bis-aqua ruthenium warhead [Ru(phen)₂(OH₂)₂]²⁺. Show less

The therapeutic approach to many solid tumors, including non-small cell lung cancer (NSCLC), is mainly based on the use of platinum-containing anticancer agents and is often characterized by acquired or intrinsic resistance to the drug. Therefore, the search for safer and more effective drugs is still an open challenge. Two organometallic ruthenium(II)-cyclopentadienyl compounds [Ru(η⁵-C₅H₄CHO)(Me₂bipy)(PPh₃)]⁺ (RT150) and [Ru(η⁵-C₅H₄CH₂OH)(Me₂bipy)(PPh₃)][CF₃SO₃] (RT151) were tested against a panel of cisplatin-resistant NSCLC cell lines and xenografts. They were more effective than cisplatin in inducing oxidative stress and DNA damage, affecting the cell cycle and causing apoptosis. Importantly, they were found to be inhibitors of drug efflux transporters. Due to this property, the compounds significantly increased the retention and cytotoxicity of cisplatin within NSCLC cells. Notably, they did not display high toxicity in vitro against non-transformed cells (red blood cells, fibroblasts, bronchial epithelial cells, cardiomyocytes, and endothelial cells). Both compounds induced vasorelaxation and reduced endothelial cell migration, suggesting potential anti-angiogenic properties. RT151 confirmed its efficacy against NSCLC xenografts resistant to cisplatin. Either alone or combined with low doses of cisplatin, RT151 showed a good biodistribution profile in the liver, kidney, spleen, lung, and tumor. Hematochemical analysis and post-mortem organ pathology confirmed the safety of the compound in vivo, also when combined with cisplatin. To sum up, we have confirmed the effectiveness of a novel class of drugs against cisplatin-resistant NSCLC. Additionally, the compounds have a good biocompatibility and safety profile. Show less

Six polypyridyl Ru(II) complexes were designed for single-molecule photodynamic and sonodynamic therapy (PDT/SDT) synergistic multimodal anticancer toward cisplatin-resistant NSCLC. They demonstrated lowest 3ES with distinct intraligand transition nature, which is beneficial for singlet oxygen generation. Remarkable quantum yields of both singlet oxygen and superoxide anion under either 808 nm laser irradiation or ultrasonic treatment and could induce apoptosis and ferroptosis of A549R cells. Cytotoxicity experiments clearly demonstrated a synergistic effect between PDT and SDT. The relationship between the structures of these complexes and their cellular biological mechanisms has been explored in detail. Using a single-molecule sensitizer to achieve synergistic PDT/SDT may provide valuable insights for the treatment of drug-resistant tumors that located deeply and in hypoxic microenvironment. 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

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

Title: Novel tris-bipyridine based Ru(II) complexes as type-I/-II photosensitizers for antitumor photodynamic therapy through ferroptosis and immunogenic cell death. Abstract: Ru(II) complexes have attracted attention as photosensitizers for their promising photodynamic properties. Herein, novel tris-bipyridine based Ru(II) complexes (6a-e) were synthesized by introducing saturated heterocycles to improve photodynamic properties and lipid-water partition coefficients. Among them, 6d demonstrated significant phototoxicity towards three cancer cells, with IC50 values of 5.66-7.17 μM, exceeding values in dark (IC50s > 100 μM). Under hypoxic conditions, 6d maintained excellent photodynamic activity in A549 cells, with PI values exceeding 24, highlighting its potential for highly effective type-I/-II photodynamic therapy by inducing ROS generation, oxidative stress, and mitochondrial damage. Additionally, it induced ferroptosis and immunogenic cell death of A549 cells by regulating the expression of relevant markers. Finally, 6d remarkably inhibited the growth of A549 transplanted tumor growth by 95.4 %. This Ru(II) complex shows great potential for cancer treatment with its potent photodynamic activity and diverse mechanisms of tumor cell death. Show less

Kinesin spindle protein (KSP) inhibitors are one of the most promising anticancer agents developed in recent years. Herein, we report the synthesis of ispinesib-core pyridine derivative conjugates, which are potent KSP inhibitors, with half-sandwich complexes of ruthenium, osmium, rhodium, and iridium. Conjugation of 7-chloroquinazolin-4(3H)-one with the pyridine-2-ylmethylimine group and the organometallic moiety resulted in up to a 36-fold increased cytotoxicity with IC₅₀ values in the micromolar and nanomolar range also toward drug-resistant cells. All studied conjugates increased the percentage of cells in the G₂/M phase, simultaneously decreasing the number of cells in the G₁/G₀ phase, suggesting mitotic arrest. Additionally, ruthenium derivatives were able to generate reactive oxygen species (ROS); however, no significant influence of the organometallic moiety on KSP inhibition was observed, which suggests that conjugation of a KSP inhibitor with the organometallic moiety modulates its mechanism of action. Show less

Anti-PD-L1 immunotherapy, a new lung cancer treatment, is limited to a few patients due to low PD-L1 expression and tumor immunosuppression. To address these challenges, the upregulation of PD-L1 has the potential to elevate the response rate and efficiency of anti-PD-L1 and alleviate the immunosuppression of the tumor microenvironment. Herein, we developed a novel usnic acid-derived Iridium(III) complex, Ir-UA, that boosts PD-L1 expression and converts "cold tumors" to "hot". Subsequently, we administered Ir-UA combined with anti-PD-L1 in mice, which effectively inhibited tumor growth and promoted CD4⁺ and CD8⁺ T cell infiltration. To our knowledge, Ir-UA is the first iridium-based complex to stimulate the expression of PD-L1 by explicitly regulating its transcription factors, which not only provides a promising platform for immune checkpoint blockade but, more importantly, provides an effective treatment strategy for patients with low PD-L1 expression. Show less

Identification of intracellular targets of anticancer drug candidates provides key information on their mechanism of action. Exploiting the ability of the anticancer (C∧N)-chelated half-sandwich iridium(III) complexes to covalently bind proteins, click chemistry with a bioorthogonal azido probe was used to localize a phenyloxazoline-chelated iridium complex within cells and profile its interactome at the proteome-wide scale. Proteins involved in protein folding and actin cytoskeleton regulation were identified as high-affinity targets. Upon iridium complex treatment, the folding activity of Heat Shock Protein HSP90 was inhibited in vitro and major cytoskeleton disorganization was observed. A wide array of imaging and biochemical methods validated selected targets and provided a multiscale overview of the effects of this complex on live human cells. We demonstrate that it behaves as a dual agent, inducing both electrophilic and oxidative stresses in cells that account for its cytotoxicity. The proposed methodological workflow can open innovative avenues in metallodrug discovery. Show less

Title: New cyclometalated iridium(III) complexes bearing substituted 2-(1H-benzimidazol-2-yl)quinoline: Synthesis, characterization, electrochemical and anticancer studies. Abstract: New iridium(III) compounds (C1-C3) bearing 2-(1H-benzimidazol-2-yl)quinoline ligands with different side groups (benzyl, 2,3,4,5,6-pentamethylbenzyl and 2,3,4,5,6-pentafluorobenzyl) were synthesized and characterized by using spectroscopic analyses. The effects of different side groups of iridium compounds on the photophysical and electrochemical properties have been investigated. The cytotoxicity and apoptosis of the compounds have been evaluated on breast cancer cell lines using various methods including MTT assay, flow cytometry, qRT-PCR, and colony formation. The cytotoxicity of C1, expressed as IC50 values, was found to be 11.76 μM for MDA-MB-231 and 5.35 μM for MCF-7 cells. For C3, the IC50 value was 16.22 μM for MDA-MB-231 and 8.85 μM for MCF-7 cells. In both cell lines, increased levels of Bax and caspase 3, along with downregulation of BCL-2 and positive annexin V staining, were observed, confirming apoptosis. Moreover, the colony-forming abilities in both cell lines decreased after C1 and C3 complex treatment. All these results suggest that the compounds C1 and C3 may have potential in the treatment of breast cancer, though further research is needed to confirm their efficacy. Show less

Autophagy is a crucial quality control mechanism that degrades damaged cellular components through lysosomal fusion with autophagosomes. However, elevated autophagy levels can promote drug resistance in cancer cells, enhancing their survival. Downregulation of autophagy through oxidative stress is a clinically promising strategy to counteract drug resistance, yet precise control of oxidative stress in autophagic proteins remains challenging. Here, a molecular design strategy of biocompatible neutral Ir(III) photosensitizers is demonstrated, B2 and B4, for precise reactive oxygen species (ROS) control at lysosomes to inhibit autophagy. The underlying molecular mechanisms for the biocompatibility and lysosome selectivity of Ir(III) complexes are explored by comparing B2 with the cationic or the non-lysosome-targeting analogs. Also, the biological mechanisms for autophagy inhibition via lysosomal oxidation are explored. Proteome analyses reveal significant oxidation of proteins essential for autophagy, including lysosomal and fusion-mediator proteins. These findings are verified in vitro, using mass spectrometry, live cell imaging, and a model SNARE complex. The anti-tumor efficacy of the precise lysosomal oxidation strategy is further validated in vivo with B4, engineered for red light absorbance. This study is expected to inspire the therapeutic use of spatiotemporal ROS control for sophisticated modulation of autophagy. Show less

Three phosphorescent iridium(III) complexes consisting bis-diphosphine ligands were prepared and characterized by single-crystal XRD, CHN analysis, spectroscopic techniques, cyclic voltammetry, and DFT. The synthesized complexes were the three monomeric [Ir(ppy)₂(L₁)Cl] (1), [Ir(ppy)₂(L₂)]Cl (2) and [Ir(ppy)₂(L₃)]Cl (3) where L₁ = bis-(diphenylphosphino)methane (dppm), L₂ = bis-(diphenylphosphino)propane (dppp) and L₃ = bis-(diphenylphosphino)benzene (dppbe). Complexes 1-3 gave an absorption band between 240 to 380 nm in both CH₂Cl₂ and DMSO, which is assigned as a charge transfer transition based on theoretical calculation. They showed a blue-green emission at 460-520 nm in DMSO with an absolute quantum efficiency of 0.013-0.046 at room temperature. The selective photo-induced electron transfer (PET) by Fe³⁺ in DMSO, was studied to obey the Rehm-Weller principle. The 1:1 binding soichiometry between 1-3 and Fe³⁺ was established by Job's plot. The binding constants (K_a) were determined using the Benesi-Hildebrand plot. All the complexes are extremely more potent than cisplatin for in vitro antiproliferative activity towards the human breast cancer cells, HCC1937, MCF-7, and MDA-MB-231. The values of IC₅₀ were in the range of 0.077-0.485 μM, and 1 exhibited the most effective IC₅₀ against MDA-MB-231 cell line, the triple-negative breast cancer cell. Their lipophilicities (log P) were also examined to explain the penetration ability of the studied complexes towards cell barriers, and transport to the molecular target. Show less