Search Results (90)

Melanoma is a malignant neoplasm that originates from melanocytes. It continues to pose a significant challenge in oncology due to its aggressive nature and limited treatment options. This study investigates the potential additive effects of PHEC-66, a cannabis extract, in combination with conventional chemotherapeutic agents auranofin, docetaxel, and cisplatin on the viability of a range of melanoma cell lines. These combinations were evaluated using the MTT assay on MM418-C1, MM329, C32, and D24 melanoma cells. There was a nuanced response observed when PHEC-66 was combined with docetaxel and auranofin in these cells, suggesting a potential additive effect. Contrastingly, the combination of PHEC-66 with cisplatin elicited an antagonistic effect, wherein the expected cytotoxicity of this drug was compromised. This unexpected interaction may stem from complex interplays between the agents that influence drug uptake, DNA damage response, and cell survival pathways. These findings underscore the importance of careful selection and assessment of drug combinations, as an additive effect and antagonistic interactions can significantly impact therapeutic outcomes. Further studies are warranted to elucidate the molecular mechanisms behind these interactions and to validate these observations using in vivo models. Full article

Auranofin, a gold(I)-based compound initially developed for the treatment of rheumatoid arthritis, has emerged as a promising anticancer agent with a multimodal mechanism of action. This review comprehensively examines the therapeutic potential of auranofin in oncology focusing on its ability to synergize with conventional and emerging cancer treatments. Here, we discuss the unique pharmacological properties of auranofin, including thioredoxin reductase inhibition, reactive oxygen species induction, and modulation of key apoptotic pathways. Moreover, this article highlights new recent evidence on its ability to synergize with other cancer treatments such as chemotherapy, immunotherapy, and targeted therapies. Particular emphasis is placed on the role of auranofin in overcoming drug resistance and its potential as an adjuvant in precision medicine. By analyzing both preclinical and clinical data, this review provides critical insights into the repositioning of auranofin as a versatile component in contemporary cancer treatment paradigms, while addressing current challenges and future directions for gold-based therapeutics in oncology. Full article

Two series of tri(2-furyl)- and triphenylphosphine-gold(I) complexes, with pyridyl- and pyrimidine-thiolate ligands containing electron-donating (-CH₃) and electron-withdrawing (-CF₃) substituents were synthesized and investigated for cell viability inhibitions. Prior results indicate that several of the gold(I) complexes in these series have high antifungal properties. The observed link between antifungal and anticancer activity provided motivation to investigate their antiproliferative effects, reported here. The synthesized compounds from both series were characterized by ¹H, ¹³C, and ³¹P NMR spectroscopy, mass spectrometry (MS), infrared and UV-Vis spectroscopy, and solution stability studies. In addition, an X-ray crystallographic study was conducted on one of the gold(I) complexes. Analyte solubilities in McCoy’s 5A cell media were evaluated by ICP-MS. Initial screening studies were conducted on the two series to evaluate cell viability using the SK-BR-3 cell line. All ten gold(I) complexes exhibited sub-µM cytotoxicity and the most potent representatives, one from each series, were selected for further evaluation in four additional cell lines. Half-maximal effective concentrations (EC₅₀) were determined for the MCF7 and MDA-MB-231 malignant mammary cell lines as well as the two control cell lines, HEK293T and MCF10A, to probe for specificity. Results indicate significant selectivity towards inhibition of cancer cells compared to non-transformed for tri(2-furyl)- and triphenylphosphine-gold(I) complexes with the 3,5-dimethylpyrimidine thiolate ligand when dissolved in cell media. Additional studies including 1% DMSO as a solubilizing agent revealed its significant impact on cellular responses. Full article

Auranofin, an FDA-approved antirheumatic drug and thioredoxin reductase 1 (TXNRD1) inhibitor, has demonstrated anti-tumoral properties, but its immunological effects are not well characterized. Here, we report that auranofin unexpectedly promotes regulatory T cell (Treg) expansion. In a B16F10 melanoma model, auranofin treatment increased lung tumor coverage, IL-10 serum levels, and FOXP3⁺CD44⁺CD4⁺ T cell frequencies. It also altered the proportion of antigen-presenting cells (APCs), increasing B cells and reducing dendritic cells. To test whether Treg expansion occurs independently of tumor antigens, we stimulated T cells ex vivo in lymph node cultures from naïve mice using anti-CD3/CD28, with or without auranofin. Auranofin increased Treg frequency in these cultures, as well as in treated human PBMCs. Similar effects were observed with the TXNRD1 inhibitor TRi-1, suggesting a ROS-dependent mechanism. Using mice with conditional expression of neutrophil cytosolic factor 1 (NCF1), we found that both TXNRD1 inhibition and APC-specific NCF1-NOX2-ROS expression enhanced tumor burden and Treg expansion. Alternatively, sorted T cells from mice harboring conditional TXNRD1 knockouts showed reduced FOXP3 and GITR expression in the naïve state and reduced tumor burden when challenged with B16F10. These data suggest TXNRD1 inhibitors likely drive Treg expansion by elevating ROS levels in APCs during T cell priming and less by intrinsic Treg TXNRD1 blockade. Our findings reveal a paradoxical immunosuppressive effect of TXNRD1 inhibitors that may contribute to their limited efficacy in immunocompetent cancer models. This work provides mechanistic insight and underscores the need to consider Treg-mediated immune suppression when designing TXNRD1-targeted therapies. Full article

Drug repurposing, that is, the identification of new therapeutic indications for existing medications, has been shown to be a cost-effective and time-efficient alternative to de novo drug development. This review provides a comprehensive overview of repurposed drugs in veterinary oncology, describing their mechanisms of action, current evidence of clinical benefit, and translational relevance. The therapeutic agents discussed include non-steroidal anti-inflammatory drugs (e.g., piroxicam), metabolic modulators (e.g., metformin), anti-parasitic drugs (e.g., fenbendazole), immunomodulators (e.g., thalidomide, oclacitinib), cardiovascular agents (e.g., propranolol, statins, losartan), and other compounds such as auranofin and disulfiram. A critical evaluation of the extant evidence-based data from preclinical research, naturally occurring tumor models, and clinical studies is provided, with particular emphasis on both the therapeutic potential and the current limitations. The present review also focused on combination strategies and multimodal protocols, where repurposed drugs may enhance the efficacy of chemotherapy, targeted therapies, or immunotherapy. Challenges to clinical implementation, including limited funding, regulatory and ethical considerations, and the need for well-designed, multi-institutional clinical trials, are discussed. Ultimately, drug repurposing represents a practical and translationally valuable approach to broaden therapeutic options, improve quality of life in companion animals, and advance comparative oncology by promoting progress that benefits both veterinary and human patients. Full article

Auranofin (AF) is an oral gold(I) compound with a well-known pharmacological profile, currently used in the treatment of some severe forms of rheumatoid arthritis. Over the last twenty years, AF has also been repurposed as an antitumor, antiviral, and antibacterial drug. In this context, this review provides an updated overview of all clinical trials investigating AF for the treatment of various pathologies, either as monotherapy or in combination with other agents. We started summarizing the rationale behind repurposing AF in oncology, including its ability to inhibit thioredoxin reductase (TrxR) and disrupt redox homeostasis, leading to selective cytotoxicity in cancer cells. Clinical data from trials across a range of tumors are reviewed, highlighting safety profiles, dosing regimens, pharmacokinetics, and observed therapeutic outcomes. Then, we discussed the synergistic effects observed when AF is combined with chemotherapeutics, targeted therapies, or immune modulators. Then, an overview concerning the trials involving AF in non-oncological settings is also provided. Despite promising preclinical results, clinical translation remains in early stages, with most trials still in phase I or II. Nevertheless, emerging evidence supports continued exploration of AF-based therapies to address unmet medical needs. Full article

Selenoprotein thioredoxin reductase 1 (TXNRD1) is frequently upregulated in various cancer cells to sustain cellular redox homeostasis, and its inhibition has emerged as a promising anti-cancer strategy. In this study, we identified PK11007, a thiol-modifying compound previously characterized as a p53 reactivator, as a potent inhibitor of TXNRD1. PK11007 irreversibly inhibited recombinant TXNRD1 in a time- and dose-dependent manner. Using differential scanning fluorimetry (DSF) and LC–MS/MS analysis, we confirmed that PK11007 covalently modifies the C-terminal redox motif (Cys⁴⁹⁷-Sec⁴⁹⁸) of TXNRD1. In non-small cell lung cancer (NSCLC) H1299 cells, PK11007-induced TXNRD1 inhibition disrupted cellular redox balance, leading to impaired autophagy flux and cell death. Similar autophagy suppression was observed in TXNRD1-knockdown cells, as well as pharmacological inhibition of TXNRD1 by Auranofin (AF) and TXNRD1 inhibitor 1 (TRi-1). Taken together, these findings highlight that oxidative stress contributes to the cytotoxic effects of PK11007 and uncover autophagy disorder as a downstream consequence of TXNRD1 inhibition. Full article

Gout is a form of sterile inflammatory arthritis in which monosodium urate (MSU) crystals deposit and provoke a neutrophil-predominant response, primarily driven by activation of the NACHT, leucine-rich repeat, and pyrin domain-containing protein 3 (NLRP3) inflammasome. Here, we show that auranofin, a Food and Drug Administration (FDA)-approved anti-rheumatic agent, exerts anti-inflammatory effects in both in vitro and in vivo models of gout. Auranofin inhibited NLRP3 inflammasome activation in human THP-1 cells and murine macrophages, leading to reduced cleavage of caspase-1, interleukin-1β (IL-1β), and interleukin-18 (IL-18). In MSU crystal-induced mouse models, auranofin treatment reduced paw swelling, serum cytokine levels, and tissue inflammation. Notably, auranofin suppressed neutrophil migration and decreased expression of C-X-C motif chemokine ligand 1 (CXCL1) in inflamed foot tissue and air-pouch exudates. Mechanistically, auranofin disrupted the interleukin-33 (IL-33)/suppression of tumorigenicity 2 (ST2) axis, a key signaling pathway promoting neutrophil recruitment. Overexpression of IL-33 abolished the anti-inflammatory effects of auranofin, highlighting the central role of IL-33 in gout pathogenesis. Together, our findings suggest that auranofin alleviates MSU-induced inflammation by concurrently inhibiting NLRP3 inflammasome activation and IL-33-mediated neutrophil recruitment, supporting its potential as a dual-action therapeutic candidate for gout. Full article

Reactive oxygen species (ROS) function as critical signaling molecules in cancer biology, promoting proliferation, angiogenesis, and metastasis at controlled levels while inducing lethal damage when exceeding the cell’s buffering capacity. To survive under this state of chronic oxidative stress, cancer cells become dependent on a hyperactive antioxidant shield, primarily orchestrated by the Nrf2, glutathione (GSH), and thioredoxin (Trx) systems. These defenses maintain redox homeostasis and sustain oncogenic signaling, notably through the oxidative inactivation of tumor-suppressor phosphatases, such as PTEN, which drives the PI3K/AKT/mTOR pathway. Targeting this addiction to a rewired redox state has emerged as a compelling therapeutic strategy. Pro-oxidant therapies aim to overwhelm cellular defenses, with agents like high-dose vitamin C and arsenic trioxide (ATO) showing significant tumor-selective toxicity. Inhibiting the master regulator Nrf2 with compounds such as Brusatol or ML385 disrupts the core antioxidant response. Disruption of the GSH system by inhibiting cysteine uptake with sulfasalazine or erastin potently induces ferroptosis, a non-apoptotic cell death driven by lipid peroxidation. Furthermore, the thioredoxin system is targeted by the repurposed drug auranofin, which irreversibly inhibits thioredoxin reductase (TrxR). Extensive preclinical data and ongoing clinical trials support the concept that this reliance on redox adaptation is a cancer-selective vulnerability. Moreover, novel therapeutic strategies, including the expanding field of redox-active metal complexes, such as manganese porphyrins, which strategically leverage the differential redox state of normal versus cancer cells through both pro-oxidant and indirect Nrf2-mediated antioxidative mechanisms (triggered by Keap1 oxidation), with several agents currently in advanced clinical trials, have also been discussed. Essentially, pharmacologically tipping the redox balance beyond the threshold of tolerance offers a rational and powerful approach to eliminate malignant cells, defining a novel frontier for targeted cancer therapy. Full article

Human fungal infections comprise systemic mycoses as well as various skin diseases. Rising case numbers along with inefficient therapies and the appearance of drug-resistant strains unleashed a considerable health problem over the last years. Thus, the identification and development of new antifungal drugs is mandatory, which can include the design of new antifungals, or, more time saving, the repurposing of known drugs already applied for the therapy of other human diseases. The orally applicable gold-based drug auranofin has been used for the treatment of rheumatoid arthritis since the 1980s. However, auranofin also showed marked activity against various cancers, microbes, parasites, and viruses. Facing a pressing need to find new drug candidates against mycoses, especially against those listed in the WHO fungal pathogen priority list, we have summarized the eminent antifungal activities of auranofin in this review. Given its established safety profile and broad-spectrum activity, auranofin represents a promising candidate for repurposing in antifungal therapy. The mechanism of action of auranofin was correlated with thioredoxin reductase inhibition, but other modes of action such as interference with mitochondrial protein import and NADH kinase were also described and discussed. A selection of promising antifungal gold complexes was also provided. Pertinent literature is covered until 2025. Full article

Reactive oxygen species (ROS) act as double-edged swords in cancer biology—facilitating tumor growth, survival, and metastasis at moderate levels while inducing oxidative damage and cell death when exceeding cellular buffering capacity. To survive under chronic oxidative stress, cancer cells rely on robust antioxidant systems such as the glutathione (GSH) and thioredoxin (Trx), and superoxide dismutases (SODs). These systems maintain redox homeostasis and sustain ROS-sensitive signaling pathways including MAPK/ERK, PI3K/Akt/mTOR, NF-κB, STAT3, and HIF-1α. Targeting the antioxidant defense mechanisms of cancer cells has emerged as a promising therapeutic strategy. Inhibiting the glutathione system induces ferroptosis, a non-apoptotic form of cell death driven by lipid peroxidation, with compounds like withaferin A and altretamine showing strong preclinical activity. Disruption of the Trx system by agents such as PX-12 and dimethyl fumarate (DMF) impairs redox-sensitive survival signaling. Trx reductase inhibition by auranofin or mitomycin C further destabilizes redox balance, promoting mitochondrial dysfunction and apoptosis. SOD1 inhibitors, including ATN-224 and disulfiram, selectively enhance oxidative stress in tumor cells and are currently being tested in clinical trials. Mounting preclinical and clinical evidence supports redox modulation as a cancer-selective vulnerability. Pharmacologically tipping the redox balance beyond the threshold of cellular tolerance offers a rational and potentially powerful approach to eliminate malignant cells while sparing healthy tissue, highlighting novel strategies for targeted cancer therapy at the interface of redox biology and oncology. Full article

Ferroptosis is an iron-dependent form of regulated cell death marked by lipid peroxidation in polyunsaturated phospholipids. In head and neck cancer (HNC), where resistance to chemotherapy and immunotherapy is common, ferroptosis offers a mechanistically distinct strategy to overcome therapeutic failure. However, cancer cells often evade ferroptosis via activation of nuclear factor erythroid 2-related factor 2 (Nrf2), a key regulator of antioxidant and iron-regulatory genes. HNC remains therapeutically challenging due to therapy resistance driven by redox adaptation. This review highlights the ferroptosis pathway—a form of regulated necrosis driven by iron and lipid peroxidation—and its regulation by Nrf2, a master antioxidant transcription factor. We detail how Nrf2 contributes to ferroptosis evasion in HNC and summarize emerging preclinical studies targeting this axis. The review aims to synthesize molecular insights and propose therapeutic perspectives for overcoming resistance in HNC by modulating Nrf2–ferroptosis signaling. We conducted a structured narrative review of the literature using PubMed databases. Relevant studies from 2015 to 2025 focusing on ferroptosis, Nrf2 signaling, and head and neck cancer were selected based on their experimental design, novelty, and relevance to clinical resistance mechanisms. In HNC, Nrf2 mediates resistance through transcriptional upregulation of GPX4 and SLC7A11, epigenetic stabilization by PRMT4 and ALKBH5, and activation by FGF5 and platelet-derived extracellular vesicles. Epstein–Barr virus (EBV) infection also enhances Nrf2 signaling in nasopharyngeal carcinoma. More recently, loss-of-function KEAP1 mutations have been linked to persistent Nrf2 activation and upregulation of NQO1, which confer resistance to both ferroptosis and immune checkpoint therapy. Targeting NQO1 in KEAP1-deficient models restores ferroptosis and reactivates antitumor immunity. Additionally, the natural alkaloid trigonelline has shown promise in reversing Nrf2-mediated ferroptosis resistance in cisplatin-refractory tumors. Pharmacologic agents such as auranofin, fucoxanthin, carnosic acid, and disulfiram/copper complexes have demonstrated efficacy in sensitizing HNC to ferroptosis by disrupting the Nrf2 axis. This review summarizes emerging mechanisms of ferroptosis evasion and highlights therapeutic strategies targeting the Nrf2–ferroptosis network. Integrating ferroptosis inducers with immune and chemotherapeutic approaches may provide new opportunities for overcoming resistance in head and neck malignancies. Full article

Leishmaniases are neglected tropical diseases caused by protozoan parasites of the Leishmania genus, with a significant global health burden, particularly in low-income regions. The parasites rely on a unique thiol-based redox system centered on trypanothione, which is essential for survival under oxidative stress encountered during their life cycle in both insect vectors and mammalian hosts. Given the absence of mammalian analogs, the trypanothione system represents an attractive target for antileishmanial drug development. However, accurate quantification of the reduced and oxidized forms of trypanothione has been challenging due to its instability and structural similarity between redox states. Here, we developed and validated a rapid, sensitive liquid chromatography–mass spectrometry (LC-MS) method for assessing the trypanothione redox state in Leishmania infantum. By incorporating N-ethylmaleimide as a thiol-blocking agent during sample preparation, the native redox state was preserved, enabling precise measurement of the reduced-to-oxidized ratio. Our approach demonstrated high sensitivity (nanomolar range), a rapid analysis time (5 min/sample), and robustness across various conditions. Moreover, we validated the method’s relevance in detecting oxidative stress and response to the trypanothione reductase inhibitor auranofin. This LC-MS technique provides a valuable tool for exploring Leishmania redox biology and supports the discovery of redox-targeting therapies against leishmaniasis. Full article

Approaches capable of simultaneously treating cancer and protecting susceptible patients from lethal infections are highly desirable, although they prove challenging. Taking inspiration from the well-known anticancer platinum complexes, successive studies about the complexation of organic compounds with other late transition metals, such as silver, gold, palladium, rhodium, ruthenium, iridium, and osmium, have led to remarkable anticancer activities. Among the numerous chemical moieties studied, N-heterocyclic carbenes (NHCs) have revealed very attractive activities due to their favorable chemical properties. Specifically, gold–NHC complexes emerged as some of the most active complexes acting as antitumor agents. On the other hand, some recent studies have highlighted the involvement of these complexes in antiviral research as well. The well-known gold-based, orally available complex auranofin approved by the Food and Drug Administration (FDA) for the treatment of rheumatoid arthritis has been suggested as a repositioned drug for both cancer and viral infections. In the era of the COVID-19 pandemic, the most interesting goal could be the discovery of gold–NHC complexes as dual antiviral and anticancer agents. In this review, the most recent studies regarding the anticancer and antiviral activities of gold(I)–NHC complexes will be analyzed and discussed, offering an interesting insight into the research in this field. Full article

Reactive oxygen species (ROS) play a key role in cancer progression and antitumor therapy. Glioblastoma is a highly heterogeneous tumor with different cell populations exhibiting various redox statuses. Elevated ROS levels in cancer cells promote tumor growth and simultaneously make them more sensitive to anticancer drugs, but further elevation leads to cell death and apoptosis. Meanwhile, various subsets of tumor cells, such a glioblastoma stem cells (GSC) or the cells in tumor microenvironment (TME), demonstrate adaptive mechanisms to excessive ROS production by developing effective antioxidant systems such as glutathione- and thioredoxin-dependent. GSCs demonstrate higher chemoresistance and lower ROS levels than other glioma cells, while TME cells create a pro-oxidative environment and have immunosuppressive effects. Both subpopulations have become an attractive target for developing therapies. Increased expression of thioredoxin reductase (TrxR) is often associated with tumor progression and poor patient survival. Various TrxR inhibitors have been investigated as potential anticancer therapies, including nitrosoureas, flavonoids and metallic complexes. Gold derivatives are irreversible inhibitors of TrxR. Among them, auranofin (AF), a selective TrxR inhibitor, has proven its effectiveness as a drug for the treatment of rheumatoid arthritis and its efficacy as an anticancer agent has been demonstrated in preclinical studies in vitro and in vivo. However, further clinical application of AF could be challenging due to the low solubility and insufficient delivery to glioblastoma. Different delivery strategies for hydrophobic drugs could be used to increase the concentration of AF in the brain. Combining different therapeutic approaches that affect the redox status of various glioma cell populations could become a new strategy for treating brain tumor diseases. Full article