The thioredoxin system and cancer therapy: a review

Rebalancing redox homeostasis: A pivotal regulator of the cGAS-STING pathway in autoimmune diseases

Autoimmune diseases (ADs) arise from the breakdown of immune tolerance to self-antigens, leading to pathological tissue damage. Proinflammatory cytokine overproduction disrupts redox homeostasis across diverse cell populations, generating oxidative stress that induces DNA damage through multiple mechanisms. Oxidative stress-induced alterations in membrane permeability and DNA damage can lead to the recognition of double-stranded DNA (dsDNA), mitochondrial DNA (mtDNA) and micronuclei-DNA (MN-DNA) by DNA sensors, thereby initiating activation of the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway. While previous reviews have characterized cGAS-STING activation in autoimmunity, the reciprocal regulation between redox homeostasis and cGAS-STING activation remains insufficiently defined. This narrative review examines oxidative stress-mediated DNA damage as a critical driver of pathological cGAS-STING signaling and delineates molecular mechanisms linking redox homeostasis to autoimmune pathogenesis. Furthermore, we propose therapeutic strategies that combine redox restoration with the attenuation of aberrant cGAS-STING activation, thereby establishing a mechanistic foundation for precision interventions in autoimmune disorders. METHODS: The manuscript is formatted as a narrative review. We conducted a comprehensive search strategy using electronic databases such as PubMed, Google Scholar and Web of Science. Various keywords were used, such as "cGAS-STING," "Redox homeostasis," "Oxidative stress," "pentose phosphate pathway," "Ferroptosis," "mtDNA," "dsDNA," "DNA damage," "Micronuclei," "Reactive oxygen species," "Reactive nitrogen species," "Nanomaterial," "Autoimmune disease," "Systemic lupus erythematosus," "Type 1 diabetes," "Rheumatoid arthritis," "Multiple sclerosis," "Experimental autoimmune encephalomyelitis," "Psoriasis," etc. The titles and abstracts were reviewed for inclusion into this review. After removing duplicates and irrelevant studies, 174 articles met inclusion criteria (original research, English language).

The involvement of thioredoxin reductase genes in development, reproduction and deltamethrin tolerance in the red flour beetle, Tribolium castaneum

As an essential component of the thioredoxin system, thioredoxin reductase (TrxR) plays an important role in maintaining redox homeostasis in mammalian cells, however, functional characterization of insect TrxRs is still limited. In this study, full-length cDNAs of TcTrxR1 and TcTrxR2 were cloned from the red flour beetle, Tribolium castaneum. Sequence analysis revealed the highly conserved active site motifs CVNVGC and CCS at the N-terminal and C-terminal of TcTrxR1, respectively, whereas TcTrxR2 lacks these two conserved motifs. Analysis of the spatio-temporal expression pattern by RT-qPCR showed that the expression of TcTrxR1 was the highest in 1-day-old larva and brain, and TcTrxR2 was highly expressed in eggs and fat body, respectively. Further functional analysis by RNA interference (RNAi) revealed that knockdown of TcTrxR1 and TcTrxR2 at the larval stage led to 100 % and 98.67 % mortality of larvae beetles, and pupal RNAi of TcTrxR1 and TcTrxR2 resulted in decreased eclosion rates as well as failure of the female adults to lay eggs. Additionally, injection of dsTcTrxR2 decreased the tolerance of beetles to deltamethrin, whereas knockdown of TcTrxR1 significantly increased the tolerance of beetles to deltamethrin. Notably, knockdown of TcTrxR1 significantly upregulated the expression of TcCYP6BQ2, TcCYP6BQ4 and TcCYP6BQ7, and led to nuclear translocation of transcription factor CncC, a major regulator of detoxification in insects. These findings provide insights into the function of insect TrxRs as well as the regulatory mechanisms of CncC, and have applied implications for the RNAi-based insect pest control.

Redox Regulation of cAMP-Dependent Protein Kinase and Its Role in Health and Disease

Protein kinase A (PKA) is a key regulator of cellular signaling that regulates key physiological processes such as metabolism, cell proliferation, and neuronal function. While its activation by the second messenger 3',5'-cyclic adenosine triphosphate (cAMP) is well characterized, recent research highlights additional regulatory mechanisms, particularly oxidative post-translational modifications, that influence PKA's structure, activity, and substrate specificity. Both the regulatory and catalytic subunits of PKA are susceptible to redox modifications, which have been shown to play important roles in the regulation of key cellular functions, including cardiac contractility, lipid metabolism, and the immune response. Likewise, redox-dependent modulation of PKA signaling has been implicated in numerous diseases, including cardiovascular disorders, diabetes, and neurodegenerative conditions, making it a potential therapeutic target. However, the mechanisms of crosstalk between redox- and PKA-dependent signaling remain poorly understood. This review examines the structural and functional regulation of PKA, with a focus on redox-dependent modifications and their impact on PKA-dependent signaling. A deeper understanding of these mechanisms may provide new strategies for targeting oxidative stress in disease and restoring balanced PKA signaling in cells.

Unilateral and Bilateral Disulfurating Reagents for the Synthesis of Unsymmetrical Polysulfides

Polysulfides play an essential role across various fields, including life sciences, pharmaceuticals, food science, and materials science. However, the controlled sequential installation of groups at both ends of an S-S motif poses enormous challenges due to the reversible nature of the covalent S-S bond. Utilizing unique disulfide reagents presents one of the most straightforward approaches for constructing diverse polysulfides. This concept highlights the initiatives and advancements in polysulfide synthesis facilitated by unilateral or bilateral disulfide reagents. Furthermore, ongoing research is focused on recently reported methodologies for synthesizing unsymmetrical disulfides.

Cotargeting of thioredoxin 1 and glutamate-cysteine ligase in both imatinib-sensitive and imatinib-resistant CML cells

Chronic myeloid leukemia (CML) is a type of malignancy characterized by harboring the oncogene Bcr-Abl, which encodes the constitutively activated tyrosine kinase BCR-ABL. Although tyrosine kinase inhibitors targeting BCR-ABL have revolutionized CML therapy, native and acquired drug resistance commonly remains a great challenge. Thioredoxin 1 (Trx1) and glutamate-cysteine ligase (GCL), which are two major antioxidants that maintain cellular redox homeostasis, are potential targets for cancer therapy and overcoming drug resistance. However, how their inhibition is implicated in CML is still unclear. Here, our results revealed that Trx1 was overexpressed in patients with CML compared with healthy donors. Trx1 expression was greater in imatinib-resistant CML cells than in imatinib-sensitive cells. Pharmacological inhibitors of Trx1 attenuated cell growth and reduced colony formation in both imatinib-sensitive and imatinib-resistant CML cells. Furthermore, decreased Trx1 expression enhanced the cytotoxicity of the GCL inhibitor buthionine sulfoximine (BSO). We surmise that the combined inhibition of Trx1 and GCL promotes the induction of hydrogen peroxide and depletes GPX4 expression in CML cells, resulting in ferroptosis in cancerous cells. Finally, the combined inhibition of Trx1 and GCL had a synergistic effect on CML cells in murine xenograft models. These findings offer crucial informationregarding the combined roles ofTrx1 and GCL in triggering ferroptosis in CML and suggestefficacioustherapeutic uses for these systems in this disease.

PX-12 modulates vorinostat-induced acetylation and methylation marks in CAL 27 cells

AIM

The hypoxic tumor microenvironment (TME) in oral squamous cell carcinoma (OSCC) is primarily regulated by hypoxia-inducible factor-1 alpha (HIF-1α), impacting histone acetylation and methylation, which contribute to drug resistance. Vorinostat, a histone deacetylase inhibitor (HDACi), de-stabilizes HIF-1α, while PX-12, a thioredoxin-1 (Trx-1) inhibitor, prevents HIF-1α accumulation. Combining HDACi with a Trx-1 inhibitor may enhance efficacy and reduce resistance by increasing reactive oxygen species (ROS) in cancer cells. This study examines how PX-12 influences vorinostat-induced histone modifications under hypoxia in the OSCC cell line CAL 27 using mass spectrometry.

MATERIALS AND METHODS

The OSCC cell line CAL 27 was used to assess histone post-translational modifications induced by PX-12 and Vorinostat under hypoxic conditions through mass spectrometry.

RESULTS

The proteomic analysis (ProteomeXchange identifier PXD053244) revealed several crucial histone marks, such as H3K4me1, H3K9ac, H3K9me, H3K14ac, H3K27me, H3K36me, H4K12Ac, and H4K16ac. Along with site-specific histone modifications, exposure of cells to vorinostat and PX-12 alone or in combination affects the global acetylation and methylation levels under hypoxia.

CONCLUSION

Mass spectrometry-based proteomics highlighted the impact of vorinostat and PX-12 on histone acetylation and methylation, offering valuable insights into the epigenetic mechanisms in OSCC and paving a way for epigenetic-based oral cancer therapeutics.

Revolutionizing radiotherapy: gold nanoparticles with polyphenol coating as novel enhancers in breast cancer cells-an in vitro study

Breast cancer is the most common cancer among women, with over 1 million new cases and around 400,000 deaths annually worldwide. This makes it a significant and costly global health challenge. Standard treatments like chemotherapy and radiotherapy, often used after mastectomy, show varying effectiveness based on the cancer subtype. Combining these treatments can improve outcomes, though radiotherapy faces limitations such as radiation resistance and low selectivity for malignant cells. Nanotechnologies, especially metallic nanoparticles (NPs), hold promise for enhancing radiotherapy. Gold nanoparticles (AuNPs) are particularly notable due to their high atomic number, which enhances radiation damage through the photoelectric effect. Studies shown that AuNPs can act as effective radiosensitizers, improving tumor damage during radiotherapy increasing the local radiation dose delivered. Traditional AuNPs synthesis methods involve harmful chemicals and extreme conditions, posing health risks. Green synthesis methods using plant extracts offer a safer and more environmentally friendly alternative. This study investigates the synthesis of AuNPs using Laurus nobilis leaf extract and their potential as radiosensitizers in breast carcinoma cell lines (MCF-7). These cells were exposed to varying doses of X-ray irradiation, and the study assessed cell viability, morphological changes and DNA damage. The results showed that green-synthesized AuNPs significantly enhanced the therapeutic effects of radiotherapy at lower radiation doses, indicating their potential as a valuable addition to breast cancer treatment.

The Elusive Biological Activity of Scorpionates: A Useful Scaffold for Cancer Therapy?

Cancer remains a formidable challenge, requiring the constant pursuit of novel therapeutic agents and strategies. Scorpionates, known for their unique coordination properties, have recently gained attention for their anticancer potential. Traditionally applied in catalysis, these compounds have demonstrated notable cytotoxicity across various cancer cell lines, often surpassing the efficacy of conventional chemotherapeutics. This review addresses recent findings on scorpionate complexes, emphasizing the impact of metal choice and ligand design on biological activity. Copper and ruthenium scorpionates show promise, leveraging redox activity and mitochondrial disruption mechanisms to selectively induce cancer cell death. Ligand modifications, including sulfur-containing heterocycles and unsubstituted pyrazoles, have proven effective in enhancing cytotoxicity and selectivity. Furthermore, dipodal ligands show unique potential, with selective binding sites that improve stability and facilitate specific cellular interactions, such as targeting metastatic pathways. These findings highlight the largely unexplored potential of scorpionate complexes, positioning them as candidates for next-generation anticancer therapies. Continued research into structure-activity relationships and precise mechanisms of action could pave the way for developing highly potent and selective anticancer agents based on scorpionate chemistry.

Concise Asymmetric Total Syntheses of (+)-Dihydropleurotinic Acid and (-)-Pleurotin, Enabling Rapid Late-Stage Diversification

(-)-Pleurotin (1) and (+)-dihydropleurotinic acid (2) are benzoquinone meroterpenoids isolated from fungal sources with powerful antitumor and antibiotic activities. Concise asymmetric total syntheses of the stereochemically pure (+)-dihydropleurotinic acid (2) and (-)-pleurotin (1) from the chiral pool (R)-Roche ester-derived vinyl bromide 7 have been achieved in 12 and 13 longest linear steps, respectively. The key transformations feature a Michael addition/alkylation cascade reaction to forge three contiguous stereocenters matched with the natural products, a PtO2-catalyzed stereoselective reduction of olefin to generate the correct stereocenter at C3, a palladium-catalyzed Negishi cross-coupling between triflate and zinc reagent to introduce the redox-sensitive para-quinone moiety, and a hydroboration/copper-catalyzed carboxylation sequence to incorporate the vital carboxyl group. Thus, the highly efficient and scalable preparation of pleurotin's pentacyclic skeleton enables the late-stage diversification, affording otherwise unavailable pleurotin analogs with significantly improved antiproliferative activities against the thioredoxin reductase (TrxR) overexpressed human breast cancer cell lines relative to the natural product pleurotin (1).

Oxidative Stress and Cancer Therapy: Controlling Cancer Cells Using Reactive Oxygen Species

Cancer is a multifaceted disease influenced by various mechanisms, including the generation of reactive oxygen species (ROS), which have a paradoxical role in both promoting cancer progression and serving as targets for therapeutic interventions. At low concentrations, ROS serve as signaling agents that enhance cancer cell proliferation, migration, and resistance to drugs. However, at elevated levels, ROS induce oxidative stress, causing damage to biomolecules and leading to cell death. Cancer cells have developed mechanisms to manage ROS levels, including activating pathways such as NRF2, NF-κB, and PI3K/Akt. This review explores the relationship between ROS and cancer, focusing on cell death mechanisms like apoptosis, ferroptosis, and autophagy, highlighting the potential therapeutic strategies that exploit ROS to target cancer cells.

Thioredoxin System Protein Expression in Carcinomas of the Pancreas, Distal Bile Duct, and Ampulla in the United Kingdom

Background: Poor survival outcomes in periampullary cancer highlight the need for improvement in biomarkers and the development of novel therapies. Redox proteins, including the thioredoxin system, play vital roles in cellular antioxidant systems. Methods: In this retrospective study, thioredoxin (Trx), thioredoxin-interacting protein (TxNIP), and thioredoxin reductase (TrxR) protein expression was assessed in 85 patients with pancreatic ductal adenocarcinoma (PDAC) and 145 patients with distal bile duct or ampullary carcinoma using conventional immunohistochemistry. Results: In patients with PDAC, high cytoplasmic TrxR expression was significantly associated with lymph node metastasis (p = 0.033). High cytoplasmic and nuclear Trx expression was significantly associated with better overall survival (p = 0.018 and p = 0.006, respectively), and nuclear Trx expression remained significant in multivariate Cox regression analysis (p < 0.0001). In distal bile duct and ampullary carcinomas, high nuclear TrxR expression was associated with vascular (p = 0.001) and perineural (p = 0.021) invasion, and low cytoplasmic TxNIP expression was associated with perineural invasion (p = 0.025). High cytoplasmic TxNIP expression was significantly associated with better overall survival (p = 0.0002), which remained significant in multivariate Cox regression analysis (p = 0.013). Conclusions: These findings demonstrate the prognostic importance of Trx system protein expression in periampullary cancers.

Glucose Metabolism-Modifying Natural Materials for Potential Feed Additive Development

Glucose, a primary energy source derived from animals' feed ration, is crucial for their growth, production performance, and health. However, challenges such as metabolic stress, oxidative stress, inflammation, and gut microbiota disruption during animal production practices can potentially impair animal glucose metabolism pathways. Phytochemicals, probiotics, prebiotics, and trace minerals are known to change the molecular pathway of insulin-dependent glucose metabolism and improve glucose uptake in rodent and cell models. These compounds, commonly used as animal feed additives, have been well studied for their ability to promote various aspects of growth and health. However, their specific effects on glucose uptake modulation have not been thoroughly explored. This article focuses on glucose metabolism is on discovering alternative non-pharmacological treatments for diabetes in humans, which could have significant implications for developing feed additives that enhance animal performance by promoting insulin-dependent glucose metabolism. This article also aims to provide information about natural materials that impact glucose uptake and to explore their potential use as non-antibiotic feed additives to promote animal health and production. Further exploration of this topic and the materials involved could provide a basis for new product development and innovation in animal nutrition.

Exploring the Thioredoxin System as a Therapeutic Target in Cancer: Mechanisms and Implications

Cells constantly face the challenge of managing oxidants. In aerobic organisms, oxygen (O2) is used for energy production, generating reactive oxygen species (ROS) as byproducts of enzymatic reactions. To protect against oxidative damage, cells possess an intricate system of redox scavengers and antioxidant enzymes, collectively forming the antioxidant defense system. This system maintains the redox equilibrium and enables the generation of localized oxidative signals that regulate essential cellular functions. One key component of this defense is the thioredoxin (Trx) system, which includes Trx, thioredoxin reductase (TrxR), and NADPH. The Trx system reverses oxidation of macromolecules and indirectly neutralizes ROS via peroxiredoxin (Prx). This dual function protects cells from damage accumulation and supports physiological cell signaling. However, the Trx system also shields tumors from oxidative damage, aiding their survival. Due to elevated ROS levels from their metabolism, tumors often rely on the Trx system. In addition, the Trx system regulates critical pathways such as proliferation and neoangiogenesis, which tumors exploit to enhance growth and optimize nutrient and oxygen supply. Consequently, the Trx system is a potential target for cancer therapy. The challenge lies in selectively targeting malignant cells without disrupting the redox equilibrium in healthy cells. The aim of this review article is threefold: first, to elucidate the function of the Trx system; second, to discuss the Trx system as a potential target for cancer therapies; and third, to present the possibilities for inhibiting key components of the Trx system, along with an overview of the latest clinical studies on these inhibitors.

Glutamate rescues heat stress-induced apoptosis of Sertoli cells by enhancing the activity of antioxidant enzymes and activating the Trx1-Akt pathway in vitro

Heat stress reduces the number of Sertoli cells, which is closely related to an imbalanced redox status. Glutamate functions to maintain the equilibrium of redox homeostasis. However, the role of glutamate in heat treated Sertoli cells remains unclear. Herein, Sertoli cells from 3-week-old piglets were treated at 44 °C for 30 min (heat stress). Glutamate levels increased significantly following heat stress treatment, followed by a gradual decrease during recovery, while glutathione (GSH) showed a gradual increase. The addition of exogenous glutamate (700 μM) to Sertoli cells before heat stress significantly reduced the heat stress-induced apoptosis rate, mediated by enhanced levels of antioxidant substances (superoxide dismutase (SOD), total antioxidant capacity (TAC), and GSH) and reduced levels of oxidative substances (reactive oxygen species (ROS) and malondialdehyde (MDA)). Glutamate addition to Sertoli cells before heat stress upregulated the levels of glutamate-cysteine ligase, modifier subunit (Gclm), glutathione synthetase (Gss), thioredoxin (Trx1) and B-cell leukemia/lymphoma 2 (Bcl-2), and the ratio of phosphorylated Akt (protein kinase B)/total Akt. However, it decreased the levels of Bcl2-associated X protein (Bax) and cleaved-caspase 3. Addition of the inhibitor of glutaminase (Gls1), Bptes (Bis-2-(5-phenylacetamido-1,3,4-thiadiazol-2-yl)ethyl sulfide, 30 μM)to Sertoli cells before heat stress reversed these effects. These results inferred that glutamate rescued heat stress-induced apoptosis in Sertoli cells by enhancing activity of antioxidant enzymes and activating the Trx1-Akt pathway. Thus, glutamate supplementation might represent a novel strategy to alleviate the negative effect of heat stress.

Pro-Oxidant Auranofin and Glutathione-Depleting Combination Unveils Synergistic Lethality in Glioblastoma Cells with Aberrant Epidermal Growth Factor Receptor Expression

Glioblastoma (GBM) is the most prevalent and advanced malignant primary brain tumor in adults. GBM frequently harbors epidermal growth factor receptor (EGFR) wild-type (EGFRwt) gene amplification and/or EGFRvIII activating mutation. EGFR-driven GBM relies on the thioredoxin (Trx) and/or glutathione (GSH) antioxidant systems to withstand the excessive production of reactive oxygen species (ROS). The impact of EGFRwt or EGFRvIII overexpression on the response to a Trx/GSH co-targeting strategy is unknown. In this study, we investigated Trx/GSH co-targeting in the context of EGFR overexpression in GBM. Auranofin is a thioredoxin reductase (TrxR) inhibitor, FDA-approved for rheumatoid arthritis. L-buthionine-sulfoximine (L-BSO) inhibits GSH synthesis by targeting the glutamate-cysteine ligase catalytic (GCLC) enzyme subunit. We analyzed the mechanisms of cytotoxicity of auranofin and the interaction between auranofin and L-BSO in U87MG, U87/EGFRwt, and U87/EGFRvIII GBM isogenic GBM cell lines. ROS-dependent effects were assessed using the antioxidant N-acetylsteine. We show that auranofin decreased TrxR1 activity and increased ROS. Auranofin decreased cell vitality and colony formation and increased protein polyubiquitination through ROS-dependent mechanisms, suggesting the role of ROS in auranofin-induced cytotoxicity in the three cell lines. ROS-dependent PARP-1 cleavage was associated with EGFRvIII downregulation in U87/EGFRvIII cells. Remarkably, the auranofin and L-BSO combination induced the significant depletion of intracellular GSH and synergistic cytotoxicity regardless of EGFR overexpression. Nevertheless, molecular mechanisms associated with cytotoxicity were modulated to a different extent among the three cell lines. U87/EGFRvIII exhibited the most prominent ROS increase, P-AKT(Ser-473), and AKT decrease along with drastic EGFRvIII downregulation. U87/EGFRwt and U87/EGFRvIII displayed lower basal intracellular GSH levels and synergistic ROS-dependent DNA damage compared to U87MG cells. Our study provides evidence for ROS-dependent synergistic cytotoxicity of auranofin and L-BSO combination in GBM in vitro. Unraveling the sensitivity of EGFR-overexpressing cells to auranofin alone, and synergistic auranofin and L-BSO combination, supports the rationale to repurpose this promising pro-oxidant treatment strategy in GBM.

The diagnostic potential role of thioredoxin reductase and TXNRD1 in early lung adenocarcinoma: A cohort study

BACKGROUND

Lung adenocarcinoma (LUAD) is the primary form of lung cancer, yet the reliable biomarkers for early diagnosis remain insufficient. Thioredoxin reductase (TrxR) is strongly linked to the occurrence, development, and drug resistance of lung cancer, making it a potential biomarker. However, further research is required to assess its diagnostic value in LUAD.

METHODS

A retrospective analysis was performed on patients who underwent pulmonary nodule resection at our center from 2018 to 2022. Clinical data, including preoperative TrxR levels, imaging, and laboratory characteristics, were identified as study variables. Two prediction models were constructed using multiple logistic regression, and their prediction performance was evaluated comprehensively. Besides, bioinformatics analyses of TrxR coding genes including differential expression, functional enrichment, immune infiltration, drug sensitivity, and single-cell landscape were performed based on TCGA database, which were subsequently validated by Human Protein Atlas.

RESULTS

A total of 506 eligible patients (72 benign lesions, 77 AISs, 185 MIAs and 172 IACs) were identified in the clinical cohort. Two TrxR-based models were developed, which were able to distinguish between benign and malignant pulmonary nodules, as well as pathological subtypes of LUAD, respectively. The models exhibited good predictive ability with all AUC values ranging from 0.7 to 0.9. Based on calibration curves and clinical decision analysis, the nomogram models showed high reliability. Functional analysis indicated that TXNRD1 primarily participated in cell cycle and lipid metabolism. Immune infiltration analysis showed that TXNRD1 has a strong association with immune cells and could impact immunotherapy. Then, we identified small molecular compounds that inhibit TXNRD1 and confirmed TXNRD1 expression by single-cell landscape and immunohistochemistry.

CONCLUSION

This study validated the diagnostic value of TrxR and TXNRD1 in clinical cohorts and transcriptional data, respectively. TrxR and TXNRD1 could be used in the risk diagnosis of early LUAD and facilitate personalized treatment strategies.

Tigecycline Opposes Bortezomib Effect on Myeloma Cells Decreasing Mitochondrial Reactive Oxygen Species Production

Multiple myeloma is an incurable plasma cell malignancy. Most patients end up relapsing and developing resistance to antineoplastic drugs, like bortezomib. Antibiotic tigecycline has activity against myeloma. This study analyzed tigecycline and bortezomib combination on cell lines and plasma cells from myeloma patients. Apoptosis, autophagic vesicles, mitochondrial mass, mitochondrial superoxide, cell cycle, and hydrogen peroxide were studied by flow cytometry. In addition, mitochondrial antioxidants and electron transport chain complexes were quantified by reverse transcription real-time PCR (RT-qPCR) or western blot. Cell metabolism and mitochondrial activity were characterized by Seahorse and RT-qPCR. We found that the addition of tigecycline to bortezomib reduces apoptosis in proportion to tigecycline concentration. Supporting this, the combination of both drugs counteracts bortezomib in vitro individual effects on the cell cycle, reduces autophagy and mitophagy markers, and reverts bortezomib-induced increase in mitochondrial superoxide. Changes in mitochondrial homeostasis and MYC upregulation may account for some of these findings. These data not only advise to avoid considering tigecycline and bortezomib combination for treating myeloma, but caution on the potential adverse impact of treating infections with this antibiotic in myeloma patients under bortezomib treatment.

Disulfidptosis decoded: a journey through cell death mysteries, regulatory networks, disease paradigms and future directions

Cell death is an important part of the life cycle, serving as a foundation for both the orderly development and the maintenance of physiological equilibrium within organisms. This process is fundamental, as it eliminates senescent, impaired, or aberrant cells while also promoting tissue regeneration and immunological responses. A novel paradigm of programmed cell death, known as disulfidptosis, has recently emerged in the scientific circle. Disulfidptosis is defined as the accumulation of cystine by cancer cells with high expression of the solute carrier family 7 member 11 (SLC7A11) during glucose starvation. This accumulation causes extensive disulfide linkages between F-actins, resulting in their contraction and subsequent detachment from the cellular membrane, triggering cellular death. The RAC1-WRC axis is involved in this phenomenon. Disulfidptosis sparked growing interest due to its potential applications in a variety of pathologies, particularly oncology, neurodegenerative disorders, and metabolic anomalies. Nonetheless, the complexities of its regulatory pathways remain elusive, and its precise molecular targets have yet to be definitively identified. This manuscript aims to meticulously dissect the historical evolution, molecular underpinnings, regulatory frameworks, and potential implications of disulfidptosis in various disease contexts, illuminating its promise as a groundbreaking therapeutic pathway and target.

Lipid Peroxidation-Related Redox Signaling in Osteosarcoma

Oxidative stress and lipid peroxidation play important roles in numerous physiological and pathological processes, while the bioactive products of lipid peroxidation, lipid hydroperoxides and reactive aldehydes, act as important mediators of redox signaling in normal and malignant cells. Many types of cancer, including osteosarcoma, express altered redox signaling pathways. Such redox signaling pathways protect cancer cells from the cytotoxic effects of oxidative stress, thus supporting malignant transformation, and eventually from cytotoxic anticancer therapies associated with oxidative stress. In this review, we aim to explore the status of lipid peroxidation in osteosarcoma and highlight the involvement of lipid peroxidation products in redox signaling pathways, including the involvement of lipid peroxidation in osteosarcoma therapies.

Can Compounds of Natural Origin Be Important in Chemoprevention? Anticancer Properties of Quercetin, Resveratrol, and Curcumin-A Comprehensive Review

Malignant tumors are the second most common cause of death worldwide. More attention is being paid to the link between the body's impaired oxidoreductive balance and cancer incidence. Much attention is being paid to polyphenols derived from plants, as one of their properties is an antioxidant character: the ability to eliminate reactive oxygen and nitrogen species, chelate specific metal ions, modulate signaling pathways affecting inflammation, and raise the level and activity of antioxidant enzymes while lowering those with oxidative effects. The following three compounds, resveratrol, quercetin, and curcumin, are polyphenols modulating multiple molecular targets, or increasing pro-apoptotic protein expression levels and decreasing anti-apoptotic protein expression levels. Experiments conducted in vitro and in vivo on animals and humans suggest using them as chemopreventive agents based on antioxidant properties. The advantage of these natural polyphenols is low toxicity and weak adverse effects at higher doses. However, the compounds discussed are characterized by low bioavailability and solubility, which may make achieving the blood concentrations needed for the desired effect challenging. The solution may lie in derivatives of naturally occurring polyphenols subjected to structural modifications that enhance their beneficial effects or work on implementing new ways of delivering antioxidants that improve their solubility and bioavailability.

Potential New Therapies "ROS-Based" in CLL: An Innovative Paradigm in the Induction of Tumor Cell Apoptosis

Chronic lymphocytic leukemia, in spite of recent advancements, is still an incurable disease; the majority of patients eventually acquire resistance to treatment through relapses. In all subtypes of chronic lymphocytic leukemia, the disruption of normal B-cell homeostasis is thought to be mostly caused by the absence of apoptosis. Consequently, apoptosis induction is crucial to the management of this illness. Damaged biological components can accumulate as a result of the oxidation of intracellular lipids, proteins, and DNA by reactive oxygen species. It is possible that cancer cells are more susceptible to apoptosis because of their increased production of reactive oxygen species. An excess of reactive oxygen species can lead to oxidative stress, which can harm biological elements like DNA and trigger apoptotic pathways that cause planned cell death. In order to upset the balance of oxidative stress in cells, recent therapeutic treatments in chronic lymphocytic leukemia have focused on either producing reactive oxygen species or inhibiting it. Examples include targets created in the field of nanomedicine, natural extracts and nutraceuticals, tailored therapy using biomarkers, and metabolic targets. Current developments in the complex connection between apoptosis, particularly ferroptosis and its involvement in epigenomics and alterations, have created a new paradigm.

Txnrd1 as a prognosticator for recurrence, metastasis and response to neoadjuvant chemotherapy and radiotherapy in breast cancer patients

Thioredoxin reductase 1 (Txnrd1) is known to have prognostic significance in a subset of breast cancer patients. Despite the pivotal role of Txnrd1 in regulating several cellular and physiological processes in cancer progression and metastasis, its clinical significance is largely unrecognized. Here, we undertook a retrospective comprehensive meta-analysis of 13,322 breast cancer patients from 43 independent cohorts to assess prognostic and predictive roles of Txnrd1. We observed that Txnrd1 has a positive correlation with tumor grade and size and it is over-expressed in higher-grade and larger tumors. Further, hormone receptor-negative and HER2-positive tumors exhibit elevated Txnrd1 gene expression. Patients with elevated Txnrd1 expression exhibit significant hazards for shorter disease-specific and overall survival. While Txnrd1 has a positive correlation with tumor recurrence and metastasis, it has a negative correlation with time to recurrence and metastasis. Txnrd1High patients exhibit 2.5 years early recurrence and 1.3 years early metastasis as compared to Txnrd1Low cohort. Interestingly, patients with high Txnrd1 gene expression exhibit a pathologic complete response (pCR) to neoadjuvant chemotherapy, but they experience early recurrence after radiotherapy. Txnrd1High MDA-MB-231 cells exhibit significant ROS generation and reduced viability after doxorubicin treatment compared to Txnrd1Low MCF7 cells. Corroborating with findings from meta-analysis, Txnrd1 depletion leads to decreased survival, enhanced sensitivity to radiation induced killing, poor scratch-wound healing, and reduced invasion potential in MDA-MB-231 cells. Thus, Txnrd1 appears to be a potential predictor of recurrence, metastasis and therapy response in breast cancer patients.

Exposure of human glioblastoma cells to thimerosal inhibits the thioredoxin system and decreases tumor growth-related factors

Glioblastoma multiforme (GBM) is the most common, aggressive, and fatal primary malignant brain tumor in adults. The therapeutic efficacy of temozolomide (TMZ) is limited owing to frequent treatment resistance. The latter is in part related to the overexpression of redox systems such as the thioredoxin system. This system is fundamental for cell survival and proliferation, regulating hypoxia inducible factor-1alpha (HIF-1α) activity, in turn controlling vascular endothelial growth factor (VEGF), which is indispensable for tumor invasiveness, angiogenesis and microenvironment maintenance. HIF-1α can also be regulated by the signal transducer and activator of transcription 3 (STAT3), an oncogene stimulated by pro-inflammatory cytokines and growth factors. The thioredoxin system has several known inhibitors including mercury compounds such as Thimerosal (TmHg) which readily crosses the blood-brain barrier (BBB) and accumulates in the brain. Though previously used in various applications epidemiological evidence on TmHg's neurotoxicity is lacking. The objective of this study was to verify whether thimerosal is a suitable candidate for hard repurposing to control glioblastoma; therefore, the effects of this molecule were evaluated in human GBM (U87) cells. Our novel results show that TmHg decreased cellular viability (>50%) and migration (up to 90% decrease in wound closure), reduced thioredoxin reductase (TrxR/TXNRD1) and thioredoxin (Trx) activity, and increased reactive oxygen species (ROS) generation. Moreover, TmHg reduced HIF-1α expression (35%) as observed by immunofluorescence. Co-exposure of U87 cells to TmHg and TMZ reduced HIF-1α, VEGF, and phosphorylated STAT3. Consequently, TmHg alone or combined with chemotherapeutic drugs can reduce neoangiogenesis and ameliorate glioblastoma progression and treatment.

Antiproliferative, antimigratory, and apoptotic effects of diffractaic and vulpinic acids as thioredoxin reductase 1 inhibitors on cervical cancer

Cervical cancer is among the most frequently observed cancer types in females. New therapeutic targets are needed because of the side impacts of existing cancer drugs and the inadequacy of treatment methods. Thioredoxin reductase 1 (TrxR1) is often overexpressed in many cancer cells, and targeting TrxR1 has become an attractive target for cancer therapy. This study investigated the anticancer impacts of diffractaic and vulpinic acids, lichen secondary metabolites, on the cervical cancer HeLa cell line. XTT findings demonstrated showed that diffractaic and vulpinic acids suppressed the proliferation of HeLa cells in a dose- and time-dependent manner and IC50 values were 22.52 μg/ml and 66.53 μg/ml at 48 h, respectively. Each of these lichen metabolites significantly suppressed migration. Diffractaic acid showed an increase in both the BAX/BCL2 ratio by qPCR analysis and the apoptotic cell population via flow cytometry analysis on HeLa cells. Concerning vulpinic acid, although it decreased the BAX/BCL2 ratio in this cells, it increased apoptotic cells according to the flow cytometry analysis results. Diffractaic and vulpinic acids significantly suppressed TrxR1 enzyme activity rather than the gene and protein expression levels in HeLa cells. This research demonstrated for the first time, that targeting TrxR1 with diffractaic and vulpinic acids was an effective therapeutic strategy for treating cervical cancer.

Peroxiredoxin 1 regulates crosstalk between pyroptosis and autophagy in oral squamous cell carcinoma leading to a potential pro-survival

Peroxiredoxin 1 (Prdx1), a vital antioxidant enzyme, has been proven to play an important role in the occurrence and development of cancers, but its effects on oral squamous cell carcinoma (OSCC) remain unclear. Here, we performed bioinformatics analysis and immunohistochemical (IHC) staining to confirm that Prdx1 was higher in OSCC tissues than in normal tissues. Consistently, RT-PCR and Western blot showed elevated Prdx1 expression in OSCC cell lines compared to human oral keratinocytes (HOK), which could be knockdown by small interfering RNA (siRNA) and Lentiviral vector delivery of short hairpin RNA (shRNA). Prdx1 silencing significantly blocked OSCC cell proliferation and metastasis, as evidenced by the CCK8, colony formation, in vivo tumorigenesis experiment, wound healing, transwell assays, and changes in migration-related factors. siPrdx1 transfection increased intracellular reactive oxygen species (ROS) levels and provoked pyroptosis, proved by the upregulation of pyroptotic factors and LDH release. Prdx1 silencing ROS-independently blocked autophagy. Mature autophagosome failed to form in the siPrdx1 group. Up-regulated autophagy limited pyroptosis triggered by Prdx1 deficiency, and down-regulated pyroptosis partly reversed siPrdx1-induced autophagy defect. Collectively, Prdx1 regulated pyroptosis in a ROS-dependent way and modulated autophagy in a ROS-independent way, involving the crosstalk between pyroptosis and autophagy.

SBP1 promotes tumorigenesis of thyroid cancer through TXN/NIS pathway

BACKGROUND

As the tissue with the highest selenium content in the body, the occurrence and development of thyroid cancer are closely related to selenium and selenoproteins. Selenium-binding protein 1 (SBP1) has been repeatedly implicated in several cancers, but its role and molecular mechanisms in thyroid cancer remains largely undefined.

METHODS

The expression of SBP1, sodium/iodide symporter (NIS) and thioredoxin (TXN) were analyzed in clinical samples and cell lines. Cell counting kit-8 (CCK-8) and tube formation assays were used to analyze the cell viability and tube formation of cells. Immunofluorescence was used to determine the expression of the NIS. Co-immunoprecipitation (Co-IP) assay was carried out to verify the interaction of SBP1 with TXN. The mouse xenograft experiment was performed to investigate the growth of thyroid cancer cells with SBP1 knockdown in vivo.

RESULTS

SBP1 was significantly increased in human thyroid cancer tissues and cells, especially in anaplastic thyroid cancer. Overexpression of SBP1 promoted FTC-133 cell proliferation, and the culture supernatant of SBP1-overexpression FTC-133 cells promoted tube formation of human retinal microvascular endothelial cells. Knockdown of SBP1, however, inhibited cell proliferation and tube formation. Furthermore, overexpression of SBP1 inhibited cellular differentiation of differentiated thyroid cancer cell line FTC-133, as indicated by decreased expression of thyroid stimulating hormone receptors, thyroglobulin and NIS. Knockdown of SBP1, however, promoted differentiation of BHT101 cells, an anaplastic thyroid cancer cell line. Notably, TXN, a negative regulator of NIS, was found to be significantly upregulated in human thyroid cancer tissues, and it was positively regulated by SBP1. Co-IP assay implied a direct interaction of SBP1 with TXN. Additionally, TXN overexpression reversed the effect of SBP1 knockdown on BHT101 cell viability, tube formation and cell differentiation. An in vivo study found that knockdown of SBP1 promoted the expression of thyroid stimulating hormone receptors, thyroglobulin and NIS, as well as inhibited the growth and progression of thyroid cancer tumors.

CONCLUSION

SBP1 promoted tumorigenesis and dedifferentiation of thyroid cancer through positively regulating TXN.

Protoporphyrin IX-loaded albumin nanoparticles reverse cancer chemoresistance by enhancing intracellular reactive oxygen species

Chemoresistance is the main cause of chemotherapy failure in ovarian cancer (OC). The enhanced scavenging of reactive oxygen species (ROS) by the thioredoxin system resulted in insufficient intracellular concentrations of effective ROS, leading to chemoresistance. To induce OC cell apoptosis by enhancing intracellular ROS levels, protoporphyrin IX (PpIX) and albumin-bound PTX nanoparticles (APNP) were utilized to fabricate APNP-PpIX nanoparticles. APNP-PpIX effectively generated ROS and increased the effective ROS concentration in chemoresistant cancer cells. The in vitro and in vivo experiments confirmed the effective inhibition of APNP-PpIX on chemoresistant OC cell proliferation and tumor formation. APNP-PpIX significantly improved the effectiveness of chemotherapy and photodynamic therapy, thus providing a new approach for the clinical treatment of chemoresistant OC.

Novel Acylselenourea Derivatives: Dual Molecules with Anticancer and Radical Scavenging Activity

Oxidative stress surrounding cancer cells provides them with certain growth and survival advantages necessary for disease progression. In this context, Se-containing molecules have gained attention due to their anticancer and antioxidant activity. In our previous work, we synthesized a library of 39 selenoesters containing functional groups commonly present in natural products (NP), which showed potent anticancer activity, but did not demonstrate high radical scavenger activity. Thus, 20 novel Se derivatives resembling NP have been synthesized presenting acylselenourea functionality in their structures. Radical scavenger activity was tested using DPPH assay and in vitro protective effects against ROS-induced cell death caused by H₂O₂. Additionally, antiproliferative activity was evaluated in prostate, colon, lung, and breast cancer cell lines, along with their ability to induce apoptosis. Compounds 1.I and 5.I showed potent cytotoxicity against the tested cancer cell lines, along with high selectivity indexes and induction of caspase-mediated apoptosis. These compounds exhibited potent and concentration-dependent radical scavenging activity achieving DPPH inhibition similar to ascorbic acid and trolox. To conclude, we have demonstrated that the introduction of Se in the form of acylselenourea into small molecules provides strong radical scavengers in vitro and antiproliferative activity, which may lead to the development of promising dual compounds.

Combination Therapy as a Promising Way to Fight Oral Cancer

Oral cancer is a highly aggressive tumor with invasive properties that can lead to metastasis and high mortality rates. Conventional treatment strategies, such as surgery, chemotherapy, and radiation therapy, alone or in combination, are associated with significant side effects. Currently, combination therapy has become the standard practice for the treatment of locally advanced oral cancer, emerging as an effective approach in improving outcomes. In this review, we present an in-depth analysis of the current advancements in combination therapies for oral cancer. The review explores the current therapeutic options and highlights the limitations of monotherapy approaches. It then focuses on combinatorial approaches that target microtubules, as well as various signaling pathway components implicated in oral cancer progression, namely, DNA repair players, the epidermal growth factor receptor, cyclin-dependent kinases, epigenetic readers, and immune checkpoint proteins. The review discusses the rationale behind combining different agents and examines the preclinical and clinical evidence supporting the effectiveness of these combinations, emphasizing their ability to enhance treatment response and overcome drug resistance. Challenges and limitations associated with combination therapy are discussed, including potential toxicity and the need for personalized treatment approaches. A future perspective is also provided to highlight the existing challenges and possible resolutions toward the clinical translation of current oral cancer therapies.

The thioredoxin expression of Cristaria plicata is regulated by Nrf2/ARE pathway under microcystin stimulation

Thioredoxin plays an important role in inhibiting apoptosis and protecting cells from oxidative stress. This study was aimed to clarify how the expression of Trx from Cristaria plicata is regulated by Nrf2/ARE pathway. The expression of CpTrx mRNA was significantly up-regulated in gill and kidney tissues under microcystin stress. The Nrf2 gene of Cristaria plicata was identified to possess an auto active domain bit. While CpNrf2 was knocked down by specific small RNA, CpTrx mRNA expression was significantly down-regulated. The promoter of CpTrx gene had high transcriptional activity, and this basic transcriptional activity persisted after ARE element mutation. The region of promoter -206 to +217 bp was a core promoter region and had forward regulatory elements. Gel shift Assay exhibited that the CpTrx promoter could bind to the purified proteins CpNrf2 and CpMafK in vitro. The binding phenomenon disappeared after the ARE element mutation in promoter region. Subcellular localization experiments displayed that fluorescence overlap between CpNrf2 and Trx promoter increased under microcystin toxin stress. These results suggested that Trx expression was regulated by Nrf2/ARE pathway under oxidative stress.

Calycosin-7-glucoside promotes mitochondria-mediated apoptosis in hepatocellular carcinoma by targeting thioredoxin 1 to regulate oxidative stress

Thioredoxin1 (TRX1) is a key protein that regulates redox and is considered to be a key target for cancer therapy. Flavonoids have been proven to have good antioxidant and anticancer activities. This study aimed to investigate whether the flavonoid calycosin-7-glucoside (CG) exerts an anti-hepatocellular carcinoma (HCC) role by targeting TRX1. Different doses of CG were used to treat HCC cell lines Huh-7 and HepG2 to calculate the IC₅₀. On this basis, the effects of low, medium and high doses of CG on cell viability, apoptosis, oxidative stress and TRX1 expression of HCC cells were investigated in vitro. Also, HepG2 xenograft mice were used to evaluate the role of CG on HCC growth in vivo. The binding mode of CG and TRX1 was explored by molecular docking. Then si-TRX1 was used to further discover the effects of TRX1 on CG inhibition of HCC. Results found that CG dose-dependent decreased the proliferation activity of Huh-7 and HepG2 cells, induced apoptosis, significantly activated oxidative stress and inhibited TRX1 expression. In vivo experiments also showed that CG dose-dependent regulated oxidative stress and TRX1 expression, and promoted the expression of apoptotic proteins to inhibit HCC growth. Molecular docking confirmed that CG had a good binding effect with TRX1. Intervention with TRX1 significantly inhibited the proliferation of HCC cells, promoted apoptosis, and further promoted the effect of CG on the activity of HCC cells. In addition, CG significantly increased ROS production, reduced mitochondrial membrane potential, regulated the expression of Bax, Bcl-2 and cleaved-caspase-3, and activated mitochondria-mediated apoptosis. And si-TRX1 enhanced the effects of CG on mitochondrial function and apoptosis of HCC, suggesting that TRX1 participated in the inhibitory effect of CG on mitochondria-mediated apoptosis of HCC. In conclusion, CG exerts anti-HCC activity by targeting TRX1 to regulate oxidative stress and promote mitochondria-mediated apoptosis.

The Value of Thioredoxin Level and its Gene Polymorphism in the Diagnosis of Post- HCV Hepatocellular Carcinoma

Background:

Hepatocellular carcinoma (HCC) is one of the most common malignancies and a leading cause of cancer-related death worldwide. Indeed, we need a novel tumor marker other than AFP for early detection and to improve the outcome. Serum thioredoxin is a promising protein involved in the pathogenesis of many malignancies. The study aims to evaluate serum thioredoxin and its gene polymorphism in HCC in cirrhotic patients due to HCV infection.

Patients and Methods:

350 patients with HCC, 350 patients with chronic liver diseases, and 300 healthy controls were enrolled in our study. Serum thioredoxin level was measured by ELISA, and molecular study of thioredoxin domain-containing 5 (TXNDC5) gene polymorphism (rs1225943) polymorphism using real-time polymerase chain reaction by Taqman allele discrimination was done for all subjects.

Results:

Our study revealed a significant increase in serum thioredoxin levels in patients with HCC compared to chronic liver diseases and healthy controls. Using the Receiver operating characteristic (ROC) curve at the area under the curve (AUC) 0.917 and a cut-off value of > 14.6 U/ml, our overall sensitivity and specificity for the HCC group over the other groups were 86 % and 92.15%, respectively with 92.2% positive predictive value and 54.9% negative predictive value. The molecular study of TXNDC5 gene polymorphism (rs1225943) polymorphism revealed no significant difference between the studied groups.

Conclusion:

Serum thioredoxin may be used as a promising tumor marker for HCC. Future research is needed to assess its use as a single or combined with other markers in the diagnosis and follow-up of the patients after interventions.

Inhibition of thioredoxin reductase activity reduces the antioxidant defense capacity of human pluripotent stem cells under conditions of mild but not severe oxidative stress

Pro-oxidative shift in redox balance, usually termed as "oxidative stress", can lead to different cell responses depending on its intensity. Excessive accumulation of reactive oxygen species ("oxidative distress") can cause DNA, lipid and protein damage. Physiological oxidative stimulus ("oxidative eustress"), in turn, can favor cell proliferation and differentiation - the processes of paramount importance primarily for stem cells. Functions of antioxidant enzymes in cells is currently a focus of intense research, however the role of different antioxidant pathways in pluripotent cell responses to oxidative distress/eustress is still under investigation. In this study, we assessed the contribution of the thioredoxin reductase (TrxR)-dependent pathways to maintaining the redox homeostasis in human induced pluripotent stem cells and their differentiated progeny cells under basal conditions and under conditions of oxidative stress of varying intensity. Employing the genetically encoded H₂O₂ biosensor cyto-HyPer and two inhibitors of thioredoxin reductase (auranofin and Tri-1), we show that the reduced activity of TrxR-dependent enzymatic systems leads to the non-cytotoxic disruption of thiol-disulfide metabolism in the cytoplasm of both pluripotent and differentiated cells under basal conditions. Quantifying the cytoplasmic concentrations of peroxide establishing in H₂O₂-stressed cells, we demonstrate that TrxR-dependent pathways contribute to the antioxidant activity in the cell cytoplasm under conditions of mild but not severe oxidative stress in both cell lines tested. The observed effects may testify about a conservative role of the TrxR-controlled enzymatic systems manifested as a response to physiological redox stimuli rather than a protection against the severe oxidative stress.

Identification of Prognostic and Predictive Biomarkers and Druggable Targets among 205 Antioxidant Genes in 21 Different Tumor Types via Data-Mining

(1) Background: Oxidative stress is crucial in carcinogenesis and the response of tumors to treatment. Antioxidant genes are important determinants of resistance to chemotherapy and radiotherapy. We hypothesized that genes involved in the oxidative stress response may be valuable as prognostic biomarkers for the survival of cancer patients and as druggable targets. (2) Methods: We mined the KM Plotter and TCGA Timer2.0 Cistrome databases and investigated 205 antioxidant genes in 21 different tumor types within the context of this investigation. (3) Results: Of 4347 calculations with Kaplan-Meier statistics, 84 revealed statistically significant correlations between high gene expression and worse overall survival (p < 0.05; false discovery rate ≤ 5%). The tumor types for which antioxidant gene expression was most frequently correlated with worse overall survival were renal clear cell carcinoma, renal papillary cell carcinoma, and hepatocellular carcinoma. Seventeen genes were clearly overexpressed in tumors compared to their corresponding normal tissues (p < 0.001), possibly qualifying them as druggable targets (i.e., ALOX5, ALOX5AP, EPHX4, G6PD, GLRX3, GSS, PDIA4, PDIA6, PRDX1, SELENOH, SELENON, STIP1, TXNDC9, TXNDC12, TXNL1, TXNL4A, and TXNRD1). (4) Conclusions: We concluded that a sub-set of antioxidant genes might serve as prognostic biomarkers for overall survival and as druggable targets. Renal and liver tumors may be the most suitable entities for this approach.

New horizons for selenium in animal nutrition and functional foods

Selenium (Se), one of the indispensable nutrients for both human health and animal growth, participates in various physiological functions, such as antioxidant and immune responses and metabolism. The role of dietary Se, in its organic and inorganic forms, has been well documented in domestic animals. Furthermore, many feeding strategies for different animals have been developed to increase the Se concentration in animal products to address Se deficiency and even as a potential nutritional strategy to treat free radical-associated diseases. Nevertheless, studies on investigating the optimum addition of Se in feed, the long-term consequences of Se usage in food for animal nutrition, the mechanism of metallic Se nanoparticle (SeNP) transformation in vivo, and the nutritional effects of SeNPs on feed workers and the environment are urgently needed. Starting from the absorption and metabolism mechanism of Se, this review discusses the antioxidant role of Se in detail. Based on this characteristic, we further investigated the application of Se in animal health and described some unresolved issues and unanswered questions warranting further investigation. This review is expected to provide a theoretical reference for improving the quality of food animal meat as well as for the development of Se-based biological nutrition enhancement technology.

Reduced Nucleotides, Thiols and O2 in Cellular Redox Balance: A Biochemist's View

In the present review, which is aimed at researchers, teachers and students in life sciences, we try to show how the physicochemical properties of the elements and molecules define the concept of redox balance. Living organism are open systems traversed by fluxes of energy and matter. During catabolic oxidative metabolism, matter-mostly hydrogenated organic molecules-is oxidized and ultimately released as CO₂. Electrons are passed over to coupling molecules, such as NAD+ and FAD, whose reduced forms serve as electrons donors in anabolic reactions. Early photosynthetic activity led to the accumulation of O₂ and the transformation of the reduction to an oxidizing atmosphere, favoring the development of oxidative metabolism in living organisms. We focus on the specific properties of O₂ that provide the chemical energy for the combustion reactions occurring in living cells. We explain the concepts of redox potential and redox balance in complex systems such as living cells, we present the main redox couples involved in cellular redox balance and we discuss the chemical properties underlying their cellular roles and, in particular, their antioxidant properties in the defense against reactive oxygen species (ROS). Finally, we try to provide an integrative view emphasizing the interplay between metabolism, oxidative stress and metabolic compartmentation in mammalian cells.

Redox-Responsive Drug Delivery Systems: A Chemical Perspective

With the widespread global impact of cancer on humans and the extensive side effects associated with current cancer treatments, a novel, effective, and safe treatment is needed. Redox-responsive drug delivery systems (DDSs) have emerged as a potential cancer treatment with minimal side effects and enhanced site-specific targeted delivery. This paper explores the physiological and biochemical nature of tumors that allow for redox-responsive drug delivery systems and reviews recent advances in the chemical composition and design of such systems. The five main redox-responsive chemical entities that are the focus of this paper are disulfide bonds, diselenide bonds, succinimide-thioether linkages, tetrasulfide bonds, and platin conjugates. Moreover, as disulfide bonds are the most commonly used entities, the review explored disulfide-containing liposomes, polymeric micelles, and nanogels. While various systems have been devised, further research is needed to advance redox-responsive drug delivery systems for cancer treatment clinical applications.

Anti-Cancer Effects of Auranofin in Human Lung Cancer Cells by Increasing Intracellular ROS Levels and Depleting GSH Levels

Auranofin, as a thioredoxin reductase (TrxR) inhibitor, has promising anti-cancer activity in several cancer types. However, little is known about the inhibitory effect of auranofin on lung cancer cell growth. We, therefore, investigated the antigrowth effects of auranofin in various lung cancer cells with respect to cell death, reactive oxygen species (ROS), and glutathione (GSH) levels. Treatment with 0~5 µM auranofin decreased cell proliferation and induced cell death in Calu-6, A549, SK-LU-1, NCI-H460, and NCI-H1299 lung cancer cells at 24 h. In addition, 0~5 µM auranofin increased ROS levels, including O2•−, and depleted GSH levels in these cells. N-acetyl cysteine (NAC) prevented growth inhibition and mitochondrial membrane potential (MMP, ∆Ψm) loss in 3 and 5 µM auranofin-treated Calu-6 and A549 cells at 24 h, respectively, and decreased ROS levels and GSH depletion in these cells. In contrast, L-buthionine sulfoximine (BSO) enhanced cell death, MMP (∆Ψm) loss, ROS levels, and GSH depletion in auranofin-treated Calu-6 and A549 cells. Treatment with 3 and 5 µM auranofin induced caspase-3 activation and poly (ADP ribose) polymerase (PARP) cleavage in Calu-6 and A549 cells, respectively. Both were prevented by NAC, but enhanced by BSO. Moreover, TrxR activity was reduced in auranofin-treated Calu-6 and A549 cells. That activity was decreased by BSO, but increased by NAC. In conclusion, these findings demonstrate that auranofin-induced cell death is closely related to oxidative stress resulted from increased ROS levels and GSH depletion in lung cancer cells.

The Thioredoxin System of Mammalian Cells and Its Modulators

Oxidative stress involves the increased production and accumulation of free radicals, peroxides, and other metabolites that are collectively termed reactive oxygen species (ROS), which are produced as by-products of aerobic respiration. ROS play a significant role in cell homeostasis through redox signaling and are capable of eliciting damage to macromolecules. Multiple antioxidant defense systems have evolved to prevent dangerous ROS accumulation in the body, with the glutathione and thioredoxin/thioredoxin reductase (Trx/TrxR) systems being the most important. The Trx/TrxR system has been used as a target to treat cancer through the thiol–disulfide exchange reaction mechanism that results in the reduction of a wide range of target proteins and the generation of oxidized Trx. The TrxR maintains reduced Trx levels using NADPH as a co-substrate; therefore, the system efficiently maintains cell homeostasis. Being a master regulator of oxidation–reduction processes, the Trx-dependent system is associated with cell proliferation and survival. Herein, we review the structure and catalytic properties of the Trx/TrxR system, its role in cellular signaling in connection with other redox systems, and the factors that modulate the Trx system.

TRX2/Rab35 Interaction Impairs Exosome Secretion by Inducing Rab35 Degradation

Given that exosomes mediate intercellular communication by delivering cellular components to recipient cells or tissue, they have the potential to be engineered to deliver therapeutic payloads. However, the regulatory mechanism of exosome secretion is poorly understood. In addition, mitochondrial components have been found in exosomes, suggesting communication between mitochondria and exosomes. However, the molecular mechanism of the mitochondria and vesicle interaction remains unclear. Here, we showed that mitochondrial thioredoxin 2 (TRX2) decreased exosome concentrations and inhibited HCT116 cell migration. Coimmunoprecipitation/mass spectrometry (Co-IP/MS) showed that TRX2 interacted with Rab35. TRX2 and Rab35 bound to each other at their N-terminal motifs and colocalized on mitochondria. Furthermore, TRX2 induced Rab35 degradation, resulting in impaired exosome secretion. Additionally, Rab35 mediated the suppressive effects of TRX2 on cell migration, and TRX2 suppressed cell migration through exosomes. Taken together, this study first found an interaction between TRX2 and Rab35. These results revealed a new role for TRX2 in the regulation of exosome secretion and cell migration and explained the upstream regulatory mechanism of Rab35. Furthermore, these findings also provide new molecular evidence for communication between mitochondria and vesicles.

Thioredoxin 1 regulates the pentose phosphate pathway via ATM phosphorylation after experimental subarachnoid hemorrhage in rats

Subarachnoid hemorrhage (SAH), a type of hemorrhagic stroke, is a neurological emergency with high morbidity and mortality. Early brain injury (EBI) after SAH is the leading cause of poor prognosis in SAH patients. TRX system is a NADPH-dependent antioxidant system which is composed of thioredoxin reductase (TRXR), thioredoxin (TRX). The pentose phosphate pathway (PPP), a pathway through which glucose can be metabolized, is a major source of NADPH. Thioredoxin 1 (TRX1) is a member of thioredoxin system mainly located in cytoplasm. Serine/threonine kinases ataxia telangiectasia mutated (ATM) is an important oxidative stress receptor, and TRX1 can regulate ATM phosphorylation and then affect the activity of PPP key enzyme glucose 6-phosphate dehydrogenase (G6PD). However, whether TRX1 is involved in the regulation of PPP pathway after subarachnoid hemorrhage remains unclear. The results showed that after SAH, the level of TRX1 and phosphor-ATM decreased while the level of TRXR1 increased. G6PD protein level remained unchanged but the activity decreased, and the NADPH contents decreased. Overexpression of TRX1 by lentivirus upregulates the level of phosphor-ATM, G6PD activity and NADPH content. TRX1 overexpression improved short-term and long-term neurobehavioral outcomes and alleviated neuronal impairment in rats. Nissl staining showed that upregulation of TRX1 reduced cortical neuron injury. Our study shows that TRX1 participates in the PPP pathway by regulating phosphorylation ATM, which is accomplished by affecting G6PD activity. TRX1 may be an important target for EBI intervention after SAH.

NRF2 and Key Transcriptional Targets in Melanoma Redox Manipulation

Melanocytes are dendritic, pigment-producing cells located in the skin and are responsible for its protection against the deleterious effects of solar ultraviolet radiation (UVR), which include DNA damage and elevated reactive oxygen species (ROS). They do so by synthesizing photoprotective melanin pigments and distributing them to adjacent skin cells (e.g., keratinocytes). However, melanocytes encounter a large burden of oxidative stress during this process, due to both exogenous and endogenous sources. Therefore, melanocytes employ numerous antioxidant defenses to protect themselves; these are largely regulated by the master stress response transcription factor, nuclear factor erythroid 2-related factor 2 (NRF2). Key effector transcriptional targets of NRF2 include the components of the glutathione and thioredoxin antioxidant systems. Despite these defenses, melanocyte DNA often is subject to mutations that result in the dysregulation of the proliferative mitogen-activated protein kinase (MAPK) pathway and the cell cycle. Following tumor initiation, endogenous antioxidant systems are co-opted, a consequence of elevated oxidative stress caused by metabolic reprogramming, to establish an altered redox homeostasis. This altered redox homeostasis contributes to tumor progression and metastasis, while also complicating the application of exogenous antioxidant treatments. Further understanding of melanocyte redox homeostasis, in the presence or absence of disease, would contribute to the development of novel therapies to aid in the prevention and treatment of melanomas and other skin diseases.

The Therapeutic Potential of Aprepitant in Glioblastoma Cancer Cells through Redox Modification

Although there is no doubt regarding the involvement of oxidative stress in the development of glioblastoma, many questions remained unanswered about signaling cascades that regulate the redox status. Given the importance of the substance P (SP)/neurokinin 1 receptor (NK1R) system in different cancers, it was of particular interest to evaluate whether the stimulation of this cascade in glioblastoma-derived U87 cells is associated with the induction of oxidative stress. Our results showed that SP-mediated activation of NK1R not only increased the intracellular levels of malondialdehyde (MDA) and reactive oxygen species (ROS) but also reduced the concentration of thiol in U87 cells. We also found that upon SP addition, there was a significant reduction in the cells' total antioxidant capacity (TAC), revealing that the SP/NK1R axis may be involved in the regulation of oxidative stress in glioblastoma cells. The significant role of SP/NK1R in triggering oxidative stress in glioblastoma has become more evident when we found that the abrogation of the axis using aprepitant reduced cell survival, probably through exerting antioxidant effects. The results showed that both MDA and ROS concentrations were significantly reduced in the presence of aprepitant, and the number of antioxidant components of the redox system increased. Overall, these findings suggest that aprepitant might exert its anticancer effect on U87 cells through shifting the balance of oxidant and antioxidant components of the redox system.

Au-24 as a Potential Thioredoxin Reductase Inhibitor in Hepatocellular Carcinoma Cells

A novel TrxR inhibitor Au-24 and its inhibitory ability to hepatocellular carcinoma in vitro and in vivo is reported herein. Au-24 can suppress HepG2 cells from proliferating by lowering mitochondrial membrane potential (MMP) and increasing reactive oxygen species (ROS) levels, resulting in oxidative stress, which causes DNA damage, autophagy, cell cycle arrest, and apoptosis. This compound can also affect the normal function of apoptosis, MAPK, PI3K/AKT/mTOR, NF-κB, STAT3 signaling pathways. In vivo experiments revealed that Au-24 inhibited HepG2 tumor growth more effectively than AA1 (chloro(triethylphosphine)gold(I)) by decreasing Ki67 and CD31 protein expression and promoting tumor cell apoptosis and necrosis lesions. As a result, Au-24 was found to be a promising candidate as a TrxR inhibitor for the treatment of hepatocellular carcinoma (HCC) in both in vivo and in vitro experiments.

The Significant Influence of a Second Metal on the Antiproliferative Properties of the Complex [Ru(η6 -C10 H14 )(Cl2 )(dmoPTA)]

Complexes [Ru(η6 -C10 H14 )(Cl2 )(HdmoPTA)](OSO2 CF3 ) (1), [Ru(η6 -C10 H14 )(Cl2 )(dmoPTA)] (2) and [Ru(η6 -C10 H14 )(Cl2 )-μ-dmoPTA-1κP:2κ2 N,N'-MCl2 ] (M=Zn (3), Co (4), Ni (5), dmoPTA=3,7-dimethyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane) have been synthesized and characterized by elemental analysis and spectroscopic techniques. The crystal structures of 1, 3 and 5 were obtained by single-crystal X-ray diffraction. The antiproliferative activity of the complexes was evaluated against colon cancer cell line Caco-2/TC7 by using the MTT protocol. The monometallic ruthenium complexes 1 and 2 were found to be inactive, but the bimetallic complexes 3, 4 and 5 display an increased activity (IC50 3: 9.07±0.27, 4: 5.40±0.19, 5: 7.15±0.30 μM) compared to cisplatin (IC50 =45.6±8.08 μM). Importantly, no reduction in normal cell viability was observed in the presence of the complexes. Experiments targeted to obtain information on the possible action mechanism of the complexes, such as cell cycle, ROS and gene expression studies, were performed. The results showed that the complexes display different properties and action mechanism depending on the nature of metal, M, bonded to the CH3 NdmoPTA atoms.

Role of Thioredoxin-1 and its inducers in human health and diseases

Thioredoxin-1 (Trx-1) is a small redox-active protein normally found in mammalian cells that responds to the changing redox environment by contributing electrons or regulating related proteins. There is growing evidence that Trx-1 has multiple functions, including cytoprotective, anti-apoptotic, antioxidant and anti-inflammatory effects. To date, researchers have found that Trx-1 deficiency leads to severe damage in various disease models, such as atherosclerosis, cerebral ischemia, diabetes and tumors. Conversely, activation of Trx-1 has a protective effect against these diseases. Accordingly, a variety of Trx-1 inducers have been widely used in the clinic with significant therapeutic value. In this paper, we summarize the pathogenesis of Trx-1 involvement in the above-mentioned diseases and describe the protective effects of Trx-1 inducers on them.

The role of polyphenols in overcoming cancer drug resistance: a comprehensive review

Chemotherapeutic drugs are used to treat advanced stages of cancer or following surgery. However, cancers often develop resistance against drugs, leading to failure of treatment and recurrence of the disease. Polyphenols are a family of organic compounds with more than 10,000 members which have a three-membered flavan ring system in common. These natural compounds are known for their beneficial properties, such as free radical scavenging, decreasing oxidative stress, and modulating inflammation. Herein, we discuss the role of polyphenols (mainly curcumin, resveratrol, and epigallocatechin gallate [EGCG]) in different aspects of cancer drug resistance. Increasing drug uptake by tumor cells, decreasing drug metabolism by enzymes (e.g. cytochromes and glutathione-S-transferases), and reducing drug efflux are some of the mechanisms by which polyphenols increase the sensitivity of cancer cells to chemotherapeutic agents. Polyphenols also affect other targets for overcoming chemoresistance in cancer cells, including cell death (i.e. autophagy and apoptosis), EMT, ROS, DNA repair processes, cancer stem cells, and epigenetics (e.g. miRNAs).

Gold(I) Complexes with P-Donor Ligands and Their Biological Evaluation

Gold(I) complexes with phosphine ligands—[Au(TrippyPhos)Cl] (1) (TrippyPhos = 1-[2-[bis(tert-butyl)phosphino]phenyl]-3,5-diphenyl-1H-pyrazole), [Au(BippyPhos)Cl]0.5CH2Cl2 (2) (BippyPhos = 5-(di-tert-butylphosphino)-1′, 3′, 5′-triphenyl-1′H-[1,4′]bipyrazole), and [Au(meCgPPh)Cl] (3) (meCgPPh = 1,3,5,7-tetramethyl-6-phenyl-2,4,8-trioxa-6-phosphaadamantane—were investigated as types of bioactive gold metallodrugs. Complexes (1)–(3) were characterized using IR, 1H, 13C, 31P NMR spectroscopy, elemental analysis and mass spectrometry (FAB-MS). Complexes of (1) and (2) exhibited substantial in vitro cytotoxicity (IC50 = 0.5–7.0 μM) against both the cisplatin-sensitive and -resistant variants of the A2780 human ovarian carcinoma cell line, as well as against the A549 human lung carcinoma, K562 chronic myelogenous leukemia, and HeLa (human cervix carcinoma) cells. However, among the compounds studied, complex (2) showed the most promising biological properties: the highest stability in biologically relevant media, selectivity towards cancer cells over the non-cancer cells (HUVEC, human umbilical vein endothelial cells), and the highest inhibitory effect on cytosolic NADPH-dependent reductases in A2780 and A2780cis cells among the gold complexes under analysis.

Comprehensive chemical proteomics analyses reveal that the new TRi-1 and TRi-2 compounds are more specific thioredoxin reductase 1 inhibitors than auranofin

Anticancer drugs that target cellular antioxidant systems have recently attracted much attention. Auranofin (AF) is currently evaluated in several clinical trials as an anticancer agent that targets the cytosolic and mitochondrial forms of the selenoprotein thioredoxin reductase, TXNRD1 and TXNRD2. Recently, two novel TXNRD1 inhibitors (TRi-1 and TRi-2) have been developed that showed anticancer efficacy comparable to AF, but with lower mitochondrial toxicity. However, the cellular action mechanisms of these drugs have not yet been thoroughly studied. Here we used several proteomics approaches to determine the effects of AF, TRi-1 and TRi-2 when used at IC50 concentrations with the mouse B16 melanoma and LLC lung adenocarcinoma cells, as these are often used for preclinical mouse models in evaluation of anticancer drugs. The results demonstrate that TRi-1 and TRi-2 are more specific TXNRD1 inhibitors than AF and reveal additional AF-specific effects on the cellular proteome. Interestingly, AF triggered stronger Nrf2-driven antioxidant responses than the other two compounds. Furthermore, AF affected several additional proteins, including GSK3A, GSK3B, MCMBP and EEFSEC, implicating additional effects on glycogen metabolism, cellular differentiation, inflammatory pathways, DNA replication and selenoprotein synthesis processes. Our proteomics data provide a resource for researchers interested in the multidimensional analysis of proteome changes associated with oxidative stress in general, and the effects of TXNRD1 inhibitors and AF protein targets in particular.