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Redox Rewiring in Nicotine-Driven Gastric Carcinogenesis: Uncovering ROS-Dependent Oncogenic Circuits.

SIGNIFICANCE: Nicotine from tobacco products, secondhand smoke, and emerging delivery systems remains a major but underappreciated driver of gastric carcinogenesis (GC). Although reactive oxygen species (ROS) have long been implicated in tumor biology, current models incompletely explain how chronic nicotine selectively reprograms gastric epithelial signaling. This review advances the concept of redox rewiring, whereby nicotine establishes a persistent oxidative state that orchestrates multiple oncogenic programs via spatially compartmentalized NOX signaling. RECENT ADVANCES: We synthesize evidence for a unified model wherein nicotine activates nAChR/β-AR signaling, Ca2+ influx, PKC, and compartmentalized NOX-derived ROS to generate distinct oncogenic outputs. Beyond the established NOX/ROS/NF-κB/MAPK-driven IL-8 and MMP-9 axes, we integrate emerging evidence into three interconnected modules governing EMT/metastasis (ABL1/STAT3/COX-2/periostin), survival/chemoresistance (ERK/GLI1/Bcl-2), and invasion/immune evasion (miR-21/PDCD4). Collectively, these circuits suggest that ROS function not merely as damaging byproducts but as spatially organized signaling mediators dictating tumor behavior. CRITICAL ISSUES: A major challenge is distinguishing established mechanisms from incompletely validated models. The three proposed axes are testable hypotheses requiring experimental validation. Most data derive from in vitro studies with nonphysiologic nicotine concentrations, and artifacts from nonspecific ROS probes are common. Compensatory pathway activation and multi-target effects of natural products remain underexplored. FUTURE DIRECTIONS: We outline a precision-redox oncology roadmap linking pathway-specific biomarkers, mechanistically matched natural products, and biomarker-enriched trials. Priorities include genetic validation of the three axes, time-resolved ROS imaging, and pulsed natural product regimens. By reframing nicotine-driven GC as adaptive redox network remodeling, this review provides a framework for prevention, stratification, and next-generation therapy. Antioxid. Redox Signal. 00, 000-000.

gastric cancer

ARID1A Mediates ROS-Induced Osteoclast Activation in TMJ Osteoarthritis.

Excessive osteoclast activation drives rapid subchondral bone destruction, serving as a critical early-stage event precipitating temporomandibular joint osteoarthritis (TMJ-OA). Although epigenetic remodeling is widely recognized as an important interface between pathological environmental signals and genomic response, the specific epigenetic mechanisms translating TMJ-OA-associated stimulation into pathological osteoclast activation remain to be elucidated. Here, using a mechanically induced TMJ-OA mouse model, we identify aberrant reactive oxygen species (ROS) accumulation as a critical upstream driver initiating excessive osteoclast activation and subsequent joint deterioration. By integrating transcriptomic and epigenomic analyses, we delineate the chromatin remodeler AT-rich interaction domain 1A (ARID1A) as an essential oxidative stress sensor within the osteoclast lineage. Mechanistically, ROS accumulation induces ARID1A upregulation and recruitment to the Src enhancer, transcriptionally activating Src and amplifying PI3K-AKT signaling to drive pathological osteoclastogenesis. Conditional knockout of Arid1a in myeloid cells effectively abrogates subchondral bone loss and cartilage destruction in TMJ-OA. Translating these mechanistic insights, we engineered an ROS-responsive, osteoclast-targeting hydrogel for the on-demand delivery of an ARID1A-dependent canonical BRG1/BRM-associated factor complex inhibitor, which successfully alleviates TMJ-OA progression. Our findings establish the epigenetic response to ROS accumulation as a key pathogenic mechanism in TMJ-OA and highlight ARID1A as a promising therapeutic target for early disease intervention.

biomaterial(s)

Accelerating diabetic wound healing by ROS-scavenging lipid nanoparticle-mRNA formulation.

Current treatment options for diabetic wounds face challenges due to low efficacy, as well as potential side effects and the necessity for repetitive treatments. To address these issues, we report a formulation utilizing trisulfide-derived lipid nanoparticle (TS LNP)-mRNA therapy to accelerate diabetic wound healing by repairing and reprogramming the microenvironment of the wounds. A library of reactive oxygen species (ROS)-responsive TS LNPs was designed and developed to encapsulate interleukin-4 (IL4) mRNA. TS2-IL4 LNP-mRNA effectively scavenges excess ROS at the wound site and induces the expression of IL4 in macrophages, promoting the polarization from the proinflammatory M1 to the anti-inflammatory M2 phenotype at the wound site. In a diabetic wound model of db/db mice, treatment with this formulation significantly accelerates wound healing by enhancing the formation of an intact epidermis, angiogenesis, and myofibroblasts. Overall, this TS LNP-mRNA platform not only provides a safe, effective, and convenient therapeutic strategy for diabetic wound healing but also holds great potential for clinical translation in both acute and chronic wound care.

Wound Healing

Malonate as a ROS product is associated with pyruvate carboxylase activity in acute myeloid leukaemia cells.

BACKGROUND: The role of anaplerotic nutrient entry into the Krebs cycle via pyruvate carboxylase has been the subject of increased scrutiny and in particular whether this is dysregulated in cancer. Here, we use a tracer-based NMR analysis involving high-resolution (1)H-(13)C-HSQC spectra to assess site-specific label incorporation into a range of metabolite pools, including malate, aspartate and glutamate in the acute myeloid leukaemia cell line K562. We also determine how this is affected following treatment with the redeployed drug combination of the lipid-regulating drug bezafibrate and medroxyprogesterone (BaP). RESULTS: Using the tracer-based approach, we assessed the contribution of pyruvate carboxylase (PC) vs. pyruvate dehydrogenase (PDH) activity in the derivation of Krebs cycle intermediates. Our data show that PC activity is indeed high in K562 cells. We also demonstrate a branched entry to the Krebs cycle of K562 cells with one branch running counterclockwise using PC-derived oxaloacetate and the other clockwise from the PDH activity. Finally, we show that the PC activity of K562 cells exclusively fuels the ROS-induced decarboxylation of oxaloacetate to malonate in response to BaP treatment; resulting in further Krebs cycle disruption via depletion of oxaloacetate and malonate-mediated inhibition of succinate dehydrogenase (SDH) resulting in a twofold reduction of fumarate. CONCLUSIONS: This study extends the interest in the PC activity in solid cancers to include leukaemias and further demonstrates the value of tracer-based NMR approaches in generating a more accurate picture of the flow of carbons and metabolites within the increasingly inappropriately named Krebs cycle. Moreover, our studies indicate that the PC activity in cancer cells can be exploited as an Achilles heel by using treatments, such as BaP, that elevate ROS production.

AML

Strigolactones constrain rice drought acclimation by suppressing ROS scavenging through the D53-OsWRKY31-ZFP36 module.

Strigolactones (SLs) are a class of plant hormones essential for tiller development and yield under diverse environmental conditions. Drought is a major limiting factor for rice yields. Although SLs contribute to drought resistance, mechanisms and practical applications of SL pathway in drought acclimation of rice remain poorly understood. Our study shows that short-term dehydration represses SL biosynthesis in rice roots. Genetic assays indicate that disruption of SL biosynthesis or signaling elevates rice drought resistance, whereas SL signaling activation or supplementation with the SL analog GR244DO impairs drought resistance. SLs negatively regulate drought acclimation by promoting degradation of the repressor protein DWARF53 (D53). D53 interacts with the transcription factor OsWRKY31 via its N-terminal domain and suppresses the protein level of OsWRKY31, which binds to and represses transcription of the ZFP36 promoter. ZFP36 encodes a zinc-finger transcription factor that promotes H2O2 scavenging to sustain reactive oxygen species (ROS) homeostasis during drought stress. Notably, the drought-resistant upland rice variety IRAT109 exhibits lower SL levels in root exudates than the lowland rice variety Nipponbare (NP). Genome editing of key components in SL pathway enhances drought resistance in NP, Huazhan (HZ), and IRAT109. The agronomic potential of tuning SL biosynthesis is further supported by the elite D17/HTD1 allele, which weakens SL biosynthesis and improves drought resistance and grain yield in Nekken 2 (NK2) under field conditions. These findings uncover a key mechanism underlying SL-repressed drought acclimation in rice and provide an effective strategy to improve drought resistance in diverse rice varieties amid ongoing climate change.

D53

CaCl2 Priming Boosts Salinity-Alkalinity Tolerance in Germinating Soybean by Reducing DNA Oxidative Damage and Enhancing Ca2+ -ROS Signaling Crosstalk.

Soybean (Glycine max) seed germination is highly sensitive to saline-alkaline stress. Seed priming represents an effective strategy to mitigate its detrimental effects. However, the optimal priming conditions (agent, concentration, duration) and the underlying molecular mechanisms remain poorly understood. This study investigated the effects of priming with distilled water (Control), calcium chloride (CaCl2), melatonin (MT), and proline (Pro) under saline-alkaline stress on soybean seed germination and the molecular basis of enhanced tolerance. Evaluation of ten germination-related parameters revealed that priming with 100 mM CaCl2 for 12 h significantly enhanced the germination rate. Physiological analyses demonstrated that CaCl2 priming effectively reduced reactive oxygen species (ROS) accumulation by increasing the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), while decreasing malondialdehyde (MDA) content. Furthermore, CaCl2 priming activated the Ca2+ signaling pathway by increasing radicle Ca2+ content and upregulating the expression levels of Ca2+ signaling-related genes (e.g., GmCAM7, GmCNGC2, GmCNGC19, GmMPK2, and GmMKK2). Additionally, CaCl2 priming significantly enhanced DNA damage repair capacity of soybean cultivars with differing saline-alkaline tolerance. This was manifested by reduced DNA oxidative damage and decreased random amplified polymorphic DNA (RAPD) polymorphism, thereby enhancing genomic stability and alleviating cell cycle arrest. These findings deepen our understanding of the complex regulatory role of calcium signaling in plant abiotic stress responses and provide important novel theoretical insights for improving crop resilience.

Glycine max

Angiotensin signaling is essential for stress erythropoiesis but causes retention of dysfunctional mitochondria in RBCs.

We previously reported that excessive angiotensin-II→AT receptor-1 (AT→ATR1) signaling results in sickle cell anemia-associated (SCA-associated) nephropathy. Herein, we showed that hyperangiotensinemia in SCA results from high erythroid cell-generated reactive oxygen species (ROS), which oxidized angiotensinogen (ATGN) and favored its rapid conversion to AT. Increased AT→ATR1 signaling in SCA erythroid cells generated ROS and created a positive feedback loop of ROS→oxidized ATGN→AT→ATR1→ROS, perpetuating the hyperangiotensinemia. ATR1 blocker, losartan, reduced erythrocyte ROS, oxidized ATGN, and AT levels. The ROS→AT→ATR1→ROS loop was driven by sickle erythropoiesis, as it was reproduced when WT mice were transplanted with SCA hematopoiesis. Using SCA and WT mice with germline- and erythroid-specific ATR1 deficiency, we found that stress erythropoiesis, but not steady-state erythropoiesis, was critically dependent on erythroid AT→ATR1 signaling, which acted in harmony with increased erythropoietin signaling. Furthermore, instead of the canonical AT→ATR1→NADPH-oxidase→ROS signaling in steady-state erythropoiesis, AT→ATR1 signaling in stress erythroid cells increased mitochondrial mass and dysfunctional mitochondria, which thereby increased ROS. SCA mice with erythroid-specific ATR1 deficiency had decreased RBC accumulation of dysfunctional mitochondria and decreased ROS, which reduced SCA-associated nephropathy. Overall, we demonstrate that AT→ATR1 signaling was essential for stress erythropoiesis but led to increased dysfunctional mitochondria retention in mature RBCs, which generated ROS and perpetuated hyperangiotensinemia, resulting in end-organ damage.

Animals

Oxidative stress and cancer: current insights and therapeutic implications.

OXIDATIVE STRESS: good or evil? Oxidative stress occurs when the balance between reactive oxygen species (ROS) and antioxidant defenses shifts toward an excess of ROS; while essential in physiological processes, it plays a context-dependent role in cancer, contributing to both the promotion and inhibition of tumorigenesis. Small to moderate amounts of ROS activate pathways supporting tumor progression and proliferation, while large amounts lead to genomic instability and cell death. ROS are generated endogenously and exogenously. In cancer, ROS activate pathways that prompt tumor development (KRAS, MYC, PI3K-Akt-mTOR) and block tumor suppressors (p53, BRCA1), allowing tumorigenesis and drug resistance. They also modulate the tumor microenvironment (TME) by altering tumor, stromal and immune cell interactions, which initiate angiogenesis, epithelial-mesenchymal transition (EMT), inflammation and metastasis. Myeloid-derived suppressor cells (MDSCs) and cancer-associated fibroblasts (CAFs) contribute to ROS-driven immunosuppression. Cancer cells mainly rely on glycolysis and oxidative phosphorylation (OXPHOS) to sustain their energetic and metabolic requirements. Generated ROS act as metabolic byproducts and signaling molecules supporting proliferation and tumorigenesis. Cancer stem cells (CSCs) produce low ROS levels by activating antioxidant pathways and mitochondria remodeling, ensuring recurrence and persistence. There is a redox duality that presents challenges and opportunities for therapies. Pro-oxidant approaches attempt to overwhelm the tumor's defenses, while antioxidants preserve healthy tissues. Advances in targeted redox modulation with immunotherapies improve therapy effectiveness. We propose a new "Adaptive Directed Redox Therapy" (ADRT), which involves a dynamic, feedback-controlled methodology that alternates pro- and antioxidant phases to selectively collapse tumor redox balance while preserving normal tissues.

Humans

Reduced R-loop abundance at proinflammatory loci: a shared epigenetic mechanism in inflammatory and metabolic diseases.

INTRODUCTION: R-loops, RNA-DNA hybrid structures with a displaced single-stranded DNA loop, are key regulators of transcriptional control, chromatin architecture, and genome stability and have emerging roles in inflammatory signaling. However, the relationship between R-loop abundance and strongly modulated inflammatory effector genes in metabolic inflammation and influenza virus infection remains underexplored. METHODS: We performed a locus-centric integrative analysis combining robust differentially expressed genes (DEGs) from multiple inflammatory and infection-related murine and human transcriptomic disease models with experimentally validated multi-cell R-loop annotations from the reference atlas RLoopBase. Our correlation framework evaluated the directional relationship between R-loop abundance and inflammatory gene expression rather than assuming disease-sample-matched R-loop measurements. We further analyzed R-loop regulatory proteins, NRF2-associated R-loop regulators, and overlaps between R-loop regulators and CRISPRi-identified mitochondrial and cellular reactive oxygen species (ROS) regulators. RESULTS: In angiotensin II-infused apolipoprotein E-deficient (ApoE-/-) mice, a model of abdominal aortic aneurysm (AAA), genomic regions encoding the top significantly upregulated genes exhibited significantly fewer R-loops than those encoding downregulated genes at days 14 and 28. Similarly, in atherosclerotic ApoE-/- mice fed a high-fat diet for 32 and 78 weeks, upregulated genes were associated with fewer R-loops than downregulated genes. Reduced R-loop abundance was also observed in genomic regions encoding the top significantly upregulated genes in liver tissues from patients with non-alcoholic steatohepatitis (NASH), as well as in monosodium urate (MSU)-stimulated lymphatic endothelial cells (LECs) and influenza virus-infected human umbilical vein endothelial cells (HUVECs). R-loop regulatory proteins upregulated during metabolic inflammation were enriched in immune and inflammatory pathways. NRF2 was identified as a regulator of 27 R-loop regulatory proteins, including 10 positively and 17 negatively regulated proteins. Furthermore, 54 R-loop regulatory proteins overlapped with CRISPRi-identified mitochondrial and cellular ROS regulators, suggesting potential reciprocal regulation between R-loop homeostasis and ROS signaling. Disease-associated changes in pro-ROS and anti-ROS R-loop regulatory proteins further linked R-loop regulation to inflammatory and oxidative stress pathways. DISCUSSION: These findings identify reduced R-loop abundance at genomic regions encoding strongly upregulated inflammatory genes as a shared feature across multiple models of metabolic inflammation and influenza virus infection. The results further suggest that immune-associated R-loop regulatory proteins and the NRF2-ROS axis may contribute to R-loop remodeling during inflammatory disease. This integrative framework provides new insight into the potential role of R-loops and ROS-sensitive R-loop regulators in inflammatory and metabolic diseases and identifies candidate pathways for future mechanistic investigation and therapeutic targeting.

R-loop regulatory proteins

Quorum-sensing agr system of Staphylococcus aureus primes gene expression for protection from lethal oxidative stress.

The agr quorum-sensing system links Staphylococcus aureus metabolism to virulence, in part by increasing bacterial survival during exposure to lethal concentrations of H2O2, a crucial host defense against S. aureus. We now report that protection by agr surprisingly extends beyond post-exponential growth to the exit from stationary phase when the agr system is no longer turned on. Thus, agr can be considered a constitutive protective factor. Deletion of agr increased both respiration and fermentation but decreased ATP levels and growth, suggesting that Δagr cells assume a hyperactive metabolic state in response to reduced metabolic efficiency. As expected from increased respiratory gene expression, reactive oxygen species (ROS) accumulated more in the agr mutant than in wild-type cells, thereby explaining elevated susceptibility of Δagr strains to lethal H2O2 doses. Increased survival of wild-type agr cells during H2O2 exposure required sodA, which detoxifies superoxide. Additionally, pretreatment of S. aureus with respiration-reducing menadione protected Δagr cells from killing by H2O2. Thus, genetic deletion and pharmacologic experiments indicate that agr helps control endogenous ROS, thereby providing resilience against exogenous ROS. The long-lived "memory" of agr-mediated protection, which is uncoupled from agr activation kinetics, increased hematogenous dissemination to certain tissues during sepsis in ROS-producing, wild-type mice but not ROS-deficient (Nox2-/-) mice. These results demonstrate the importance of protection that anticipates impending ROS-mediated immune attack. The ubiquity of quorum sensing suggests that it protects many bacterial species from oxidative damage.

Staphylococcus aureus

Quorum-sensing agr system of Staphylococcus aureus primes gene expression for protection from lethal oxidative stress.

The agr quorum-sensing system links Staphylococcus aureus metabolism to virulence, in part by increasing bacterial survival during exposure to lethal concentrations of H2O2, a crucial host defense against S. aureus. We now report that protection by agr surprisingly extends beyond post-exponential growth to the exit from stationary phase when the agr system is no longer turned on. Thus, agr can be considered a constitutive protective factor. Deletion of agr resulted in decreased ATP levels and growth, despite increased rates of respiration or fermentation at appropriate oxygen tensions, suggesting that Δagr cells undergo a shift towards a hyperactive metabolic state in response to diminished metabolic efficiency. As expected from increased respiratory gene expression, reactive oxygen species (ROS) accumulated more in the agr mutant than in wild-type cells, thereby explaining elevated susceptibility of Δagr strains to lethal H2O2 doses. Increased survival of wild-type agr cells during H2O2 exposure required sodA, which detoxifies superoxide. Additionally, pretreatment of S. aureus with respiration-reducing menadione protected Δagr cells from killing by H2O2. Thus, genetic deletion and pharmacologic experiments indicate that agr helps control endogenous ROS, thereby providing resilience against exogenous ROS. The long-lived 'memory' of agr-mediated protection, which is uncoupled from agr activation kinetics, increased hematogenous dissemination to certain tissues during sepsis in ROS-producing, wild-type mice but not ROS-deficient (Cybb-/-) mice. These results demonstrate the importance of protection that anticipates impending ROS-mediated immune attack. The ubiquity of quorum sensing suggests that it protects many bacterial species from oxidative damage.

Staphylococcus aureus

Impact of oxidative stress on malignant tumor progression and emerging therapeutic strategies.

Oxidative stress, driven by an imbalance between reactive oxygen species (ROS) production and antioxidant defenses, plays a pivotal role in cancer biology. While persistent, moderately elevated ROS levels can promote genomic instability, tumor progression, and immune evasion, excessive ROS accumulation can overwhelm antioxidant defenses and trigger cancer cell death. Despite promising preclinical findings, clinical translation remains a challenge because of the context-dependent effects of ROS. A deeper understanding of oxidative stress regulation may lead to the development of novel precision medicine strategies, optimizing cancer therapies while minimizing adverse effects. This review highlights the concentration-dependent effects of oxidative stress in tumorigenesis, focusing on its impact on DNA damage, metabolic reprogramming, and immune modulation. We discuss recent advancements in ROS-targeting strategies, including pro-oxidant therapies that exploit redox vulnerabilities in cancer cells and antioxidant-based approaches aimed at mitigating oxidative stress-driven resistance to treatment. Moreover, we examine the interplay between oxidative stress and the tumor microen-vironment, emphasizing its influence on immune surveillance and therapeutic responses. This re-view provides insights into ROS-targeting interventions and their potential in oncologic treatment paradigms.

malignant tumors

Abscisic acid promotes RBOH-dependent reactive oxygen species production and lignin biosynthesis in pears via the PuABI5-PuMYB169 module.

Pear stone cell lignification, a critical determinant of fruit texture and quality, is regulated by developmental and environmental cues, with abscisic acid (ABA) playing a central role. However, the molecular mechanisms underlying its role in reactive oxygen species (ROS)-mediated lignification remain unclear. Here, we show that PuABI5, a key component in ABA signaling, directly combines with PuMYB169, the master regulator of stone cell lignification, to modulate ROS production and lignin biosynthesis in pear fruit. Exogenous application of ABA enhances H2O2 and lignin accumulation in both pear fruits and calli, and ABA-activated PuABI5 positively regulates stone cell lignification. We demonstrate that ABA-induced PuABI5 binds directly to the PuMYB169 promoter and activates its expression to promote the transcription of PuRBOHF and lignin-related genes, thereby enhancing ROS production and lignin accumulation. Notably, PuABI5 interacted with PuMYB169 to enhance the induction of PuRBOHF expression, leading to elevated levels of H2O2, which feedback to strengthen the interaction between PuABI5 and PuMYB169. Collectively, our findings elucidate that ABA induces ROS-mediated lignification of stone cells in pears by activating the PuABI5-PuMYB169 transcriptional module.

Lignin

CBL1/9-CIPK6 complex negatively regulates Respiratory burst oxidase homolog D in Arabidopsis thaliana.

Plant innate immune response is a well-balanced process with positive and negative regulations for the plants to survive. Calcium signaling is essential for pathogen-associated molecular pattern (PAMP)-driven respiratory burst oxidase homolog D (RBOHD)-mediated reactive oxygen species (ROS) burst. We show that calcium sensors calcineurin B like protein 1 (CBL1) and CBL9 and their interacting protein kinase CIPK6 negatively regulate RBOHD activity and immune response in Arabidopsis thaliana. Arabidopsis mutant cbl1cbl9, like cipk6, exhibited enhanced resistance and ROS production when infected with the bacterial pathogen Pseudomonas syringae pv. tomato (Pst). CBL1 and CBL9 enhanced kinase activity of CIPK6. CBL1/9-CIPK6 module interacts with RBOHD at the plasma membrane. CIPK6 along with CBL1 reduces RBOHD activity in planta. CIPK6 phosphorylates the N-terminal cytoplasmic domain of RBOHD at a non-conserved (S33) and a conserved (S39) serine residue. While S39 phosphorylation increased RBOHD activity, S33 phosphorylation drastically reduced it and superseded the effect of S39 phosphorylation. We propose a model that CIPK6 phosphorylates RBOHD at S33 to suppress its activity to balance ROS generation in post-PTI situation in Arabidopsis. Our study reports a direct mechanism of negative regulation of ROS production and plant immune response by a calcium-signaling module in Arabidopsis thaliana.

Arabidopsis

Derivation and characterization of ubiquitin-specific protease 18 inhibitors.

Ubiquitin-Specific Protease 18 (USP18) is a deISGylation enzyme and antineoplastic target. To develop USP18 inhibitors, an enzymatically active human recombinant USP18 protein was engineered suitable for high-throughput screening of ~80,000 chemical compounds. Three of them substantially inhibited USP18 enzymatic activity, with β-lapachone having prominent antineoplastic activity. Independent β-lapachone treatments of murine and human lung cancer cell lines statistically significantly reduced proliferation and increased apoptosis. Gain of USP18 expression antagonized these effects. β-Lapachone treatments statistically significantly repressed lung cancer xenograft growth. β-Lapachone increased reactive oxygen species (ROS), but antineoplastic effects occurred at dosages with negligible ROS production. ROS scavenger treatments did not rescue β-lapachone effects at these concentrations, consistent with an ROS-independent mechanism. IFN-Stimulated Response Element (ISRE) reporter assays following β-lapachone treatment activated this reporter. USP18 cotransfection antagonized this activity. β-Lapachone treatments increased global ISGylation. RNA-seq of lung cancer cells engineered with or without enhanced USP18 expression showed specific pathways affected by β-lapachone treatment. Proteomic analysis of these treated cells revealed known and new ISGylated proteins. In silico modeling identified a unique USP18 pocket where these USP18 inhibitors bind. Engineered mutation of this pocket disrupted β-lapachone activity. Taken together, β-lapachone is an antineoplastic tool compound useful for USP18 inhibitor development.

Humans

Glutathione reductase deficiency potentiates the immunogenicity of ferroptosis and cuproptosis via amplified reactive oxygen species accumulation and cGAS-STING pathway activation.

BACKGROUND: Cancer remains a major therapeutic challenge due to drug resistance and metastasis, processes driven by oxidative stress and redox imbalance. Targeting this vulnerability through ferroptosis (iron-dependent lipid peroxidation) and cuproptosis (copper-driven mitochondrial dysfunction), two ROS-mediated cell death pathways, offers a promising therapeutic strategy. However, clinical translation is hindered by incomplete understanding of their redox regulation and limited immunogenicity. METHODS: A genome-wide CRISPR knockout screen was performed to identify key regulators of ferroptosis. Genetic depletion or pharmacological inhibition of candidate genes was evaluated across multiple cancer cell lines for sensitivity to ferroptosis inducer RSL3 and the cuproptosis inducer elesclomol (Es). Antitumor efficacy was assessed in xenograft, orthotopic, metastatic, and syngeneic mouse models, alone or combined with immune checkpoint inhibitors. Mechanistic studies also examined ROS production, mitochondrial stress, mitochondrial DNA release, cGAS-STING activation, and immune responses within the tumor microenvironment. RESULTS: Glutathione reductase (GSR), a central enzyme maintaining reduced glutathione (GSH) homeostasis, was identified as the top suppressor of ferroptosis. GSR knockout or pharmacological inhibition markedly sensitized diverse cancer cell lines to RSL3-induced ferroptosis, while GSR overexpression conferred resistance. Strikingly, GSR depletion also enhanced sensitivity to cuproptosis triggered by the copper ionophore Es. In multiple in vivo tumor models, GSR inhibition synergizes with RSL3 or Es to suppress tumor growth, inhibit lung metastasis, and prolong survival. Mechanistically, GSR deficiency amplified ROS production, induced mitochondrial stress, and triggered the cytosolic mitochondrial DNA release under ferroptotic or cuproptotic stress, activating the cGAS-STING pathway in vitro and in vivo. This increased inflammatory cytokine production, promoted immunogenic cell death, and enhanced the release of damage-associated molecular patterns (DAMPs), including HMGB1. Together, GSR inhibition combined with a ferroptosis or cuproptosis inducer transformed the tumor microenvironment into a highly immune stimulatory state, thereby enhancing the efficacy of immune checkpoint blockade through increased dendritic cell activation and T-cell infiltration and activation. CONCLUSIONS: GSR represents a key molecular node connecting and modulating ferroptosis and cuproptosis through redox regulation. Targeting GSR amplifies ROS-mediated immunogenic cell death, triggers cGAS-STING activation in cancer cells, and enhances the efficacy of cancer immunotherapy, providing a promising redox-based therapeutic strategy.

Ferroptosis

Experimental workflows for the accurate identification of mitochondrial redox events.

The study of redox biology has been growing constantly since the last decades. Over these years, redox processes have been linked to an extraordinarily wide range of physiological and pathological events, becoming recognized as central mechanisms underlying many of them. In this context, it becomes essential to understand the advantages and limitations of the tools under use, to recognize the specific controls required for each measurement and to accurately distinguish between distinct redox mechanisms. So far, multiple and excellent reviews have dealt with either the tools, the protocols or the mechanisms involved in reactive oxygen species (ROS) production and quenching, a.k.a. redox events. However, a review outlining the workflows to appropriately detect them is still lacking. We define workflow as the combination of tools, methods and mechanistic knowledge that allow the definition of a specific redox event. In this review, we aim to provide an optimal workflow for the research on mitochondrial redox events. To this end, we first summarize the molecular tools available to measure and quench ROS. We then explain the mechanisms of ROS production and scavenging in several of the cellular compartments, with special focus on mitochondria, as well as their implication in physiology and disease. Finally, we use the knowledge in all sections to build a recommended experimental workflow, illustrated by several cases of study. This review will enable the reader to understand how specific mitochondrial redox events can be accurately measured, considering all technical, methodological and mechanistical variables and limitations required for their reliable detection and interpretation.

(Patho)physiology

Activation of pro-survival autophagy by a small molecule promoting p62 oligomerization.

Autophagy is a critical mechanism of cellular quality control, orchestrated by selective autophagy receptor (SAR) proteins. Pharmacologically enhancing the cargo-targeting capacity of SARs presents an attractive but underexplored strategy for the precise therapeutic activation of autophagy. Here, we characterize SQ-1, a small-molecule activator of autophagy that engages the prototypical SAR protein p62/sequestosome-1 (SQSTM1). We show that SQ-1 sensitizes p62 to oxidation and promotes its disulfide-mediated oligomerization in response to mitochondrial reactive oxygen species (ROS). This ROS-dependent activation of p62-mediated selective autophagy enhances the clearance of ROS-generating mitochondria and restores cell viability in models of Niemann-Pick type C1 disease, which is marked by impaired autophagic flux. In summary, the unique mode of action of SQ-1 enables self-regulated autophagy activation, offering a potential therapeutic strategy for lysosomal storage disorders and a broader spectrum of age-related diseases characterized by defective autophagy.

Niemann-Pick type C1 disease