NRF2 and cancer: the good, the bad and the importance of context

Nrf2-Keap1 in Cardiovascular Disease: Which Is the Cart and Which the Horse?

High levels of oxidant stress in the form of reactive oxidant species are prevalent in the circulation and tissues in various types of cardiovascular disease including heart failure, hypertension, peripheral arterial disease, and stroke. Here we review the role of nuclear factor erythroid 2-related factor 2 (Nrf2), an important and widespread antioxidant and anti-inflammatory transcription factor that may contribute to the pathogenesis and maintenance of cardiovascular diseases. We review studies showing that downregulation of Nrf2 exacerbates heart failure, hypertension, and autonomic function. Finally, we discuss the potential for using Nrf2 modulation as a therapeutic strategy for cardiovascular diseases and autonomic dysfunction.

Roquin-2 promotes oxidative stress-induced cell death by ubiquitination-dependent degradation of TAK1

Reactive oxygen species (ROS) are highly reactive and their accumulation causes oxidative damage to cells. Cells maintain survival upon mild oxidative stress with anti-oxidative systems, such as the kelch-like ECH-associated protein 1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) system. On the other hand, upon severe oxidative stress, cells undergo regulated cell death, including apoptosis, for eliminating damaged cells. To execute efficient cell death, cells need to turn off the anti-oxidant systems, while triggering cell death. However, it remains unknown how cells orchestrate these two conflicting systems under excessive oxidative stress. Herein, we show that when cells are exposed to excessive oxidative damage, an E3 ubiquitin ligase Roquin-2 (also known as RC3H2) plays a key role in switching cell fate from survival to death by terminating activation of transforming growth factor-β-activated kinase 1 (TAK1), a positive regulator for Nrf2 activation. Roquin-2 interacted with TAK1 via four cysteine residues in TAK1 (C96, C302, C486, and C500) that are susceptible to oxidative stress and participate in oligomer formation via disulfide bonds, promoting K48-linked polyubiquitination and degradation of TAK1. Nrf2 was inactivated upon lethal oxidative stress in wild-type mouse embryonic fibroblast (MEF) cells, whereas it sustained activation and conferred resistance to Roquin-2 deficient cells, which was reversed by pharmacological or genetic inhibition of TAK1. These data demonstrate that in response to excessive ROS exposure, Roquin-2 promotes ubiquitination and degradation of TAK1 to suppress Nrf2 activation, and thereby contributes to an efficient cell death, providing insight into the pathogenesis of oxidative stress-related diseases, including cancer.

Developing targeted therapeutics for hepatocellular carcinoma: a critical assessment of promising phase II agents

INTRODUCTION

Hepatocellular carcinoma (HCC) is the sixth most common cancer worldwide and the first for primary liver tumors. In recent years greater therapeutic advancement was represented by employment of tyrosine kinase inhibitors (TKIs) either in monotherapy or in combination with immune checkpoint inhibitors (ICIs).

AREAS COVERED

Major attention was given to target therapies in the last couple of years, especially in those currently under phase II trials. Priority was given either to combinations of novel ICI and TKIs or those targeting alternative mutations of major carcinogenic pathways.

EXPERT OPINION

As TKIs are playing a more crucial role in HCC therapeutic strategies, it is fundamental to further expand molecular testing and monitoring of acquired resistances. Despite the recent advancement in both laboratory and clinical studies, further research is necessary to face the discrepancy in clinical practice.

A core NRF2 gene set defined through comprehensive transcriptomic analysis predicts selective drug resistance and poor multi-cancer prognosis

AIMS

The NRF2-KEAP1 pathway plays an important role in the cellular response to oxidative stress but may also contribute to metabolic changes and drug resistance in cancer. However, despite its pervasiveness and important role, most of NRF2 target genes are defined in context specific experiments and analysis, making it difficult to translate from one situation to another. Our study investigates whether a core NRF2 gene signature can be derived and used to represent NRF2 in various contexts, allowing better reproducibility and understanding of NRF2 activation.

RESULTS

We define a core set of 14 upregulated NRF2 target genes from seven RNA-sequencing datasets that we generated and analyzed. This NRF2 gene signature was validated using analyses of published datasets and gene sets. An NRF2 activity score based on expression of these core target genes correlates with resistance to drugs such as PX-12 and necrosulfonamide but not to paclitaxel or bardoxolone methyl. We validated these findings in our KEAP1 knockout cancer cell lines. Finally, our NRF2 score is prognostic for cancer survival and validated in additional independent cohorts for lung adenocarcinoma and also novel cancers types not associated with NRF2-KEAP1 mutations such as clear cell renal carcinoma, hepatocellular carcinoma, and acute myeloid leukemia.

INNOVATION AND CONCLUSIONS

These analyses define a core NRF2 gene signature that is robust, versatile, and useful for evaluating NRF2 activity and for predicting drug resistance and cancer prognosis. Using this gene signature, we uncover novel selective drug resistance and cancer prognosis associated with NRF2 activation.

A tandem activity-based sensing and labeling strategy reveals antioxidant response element regulation of labile iron pools

Iron is an essential element for life owing to its ability to participate in a diverse array of oxidation-reduction reactions. However, misregulation of iron-dependent redox cycling can also produce oxidative stress, contributing to cell growth, proliferation, and death pathways underlying aging, cancer, neurodegeneration, and metabolic diseases. Fluorescent probes that selectively monitor loosely bound Fe(II) ions, termed the labile iron pool, are potentially powerful tools for studies of this metal nutrient; however, the dynamic spatiotemporal nature and potent fluorescence quenching capacity of these bioavailable metal stores pose challenges for their detection. Here, we report a tandem activity-based sensing and labeling strategy that enables imaging of labile iron pools in live cells through enhancement in cellular retention. Iron green-1 fluoromethyl (IG1-FM) reacts selectively with Fe(II) using an endoperoxide trigger to release a quinone methide dye for subsequent attachment to proximal biological nucleophiles, providing a permanent fluorescent stain at sites of elevated labile iron. IG1-FM imaging reveals that degradation of the major iron storage protein ferritin through ferritinophagy expands the labile iron pool, while activation of nuclear factor-erythroid 2-related factor 2 (NRF2) antioxidant response elements (AREs) depletes it. We further show that lung cancer cells with heightened NRF2 activation, and thus lower basal labile iron, have reduced viability when treated with an iron chelator. By connecting labile iron pools and NRF2-ARE activity to a druggable metal-dependent vulnerability in cancer, this work provides a starting point for broader investigations into the roles of transition metal and antioxidant signaling pathways in health and disease.

Ethnic Differences, Lung Cancer Risk, and Association of NRF2 Gene Polymorphism with Gemcitabine-Based Chemotherapy

INTRODUCTION

The cancer burden is rising every year. Lung cancer is one of the most common cancers and non-small cell lung cancer is the most common type. Chemotherapy based on platinum drugs and third-generation nucleoside anti-metabolites such as gemcitabine are used widely. Gemcitabine has a complex metabolic pathway, with many mechanisms contributing to its cytotoxicity. Derangements in the metabolic pathway genes contribute to drug resistance and toxicity with this drug. Association studies including these genetic polymorphisms in the metabolic pathway, clinical outcomes, and cancer risk reported inter-individual differences. Thus, the aim of this study was to ascertain the role of these genetic variants in South Indian cancer patients treated with gemcitabine-based therapy.

METHODS

The study was done with 184 healthy volunteers for frequency establishment and 123 cancer patients were treated with gemcitabine-based chemotherapy for response and toxicity assessment. The participants were aged 18-65 years and resided in the southern states of India. DNA extraction was done from the leukocyte fraction of the blood by phenol-chloroform extraction procedures and genotyping was done by reverse transcription-polymerase chain reaction (RT-PCR) techniques to identify DNA repair gene polymorphisms. Tumor response was determined using Response evaluation criteria in solid tumors (RECIST) guidelines and toxicity using Common Terminology Criteria for Adverse Events (CTCAE), version 4.03. The patients were followed up for survival analysis.

RESULTS

The minor allele frequency of the single nucleotide polymorphism (SNP) NRF2-617 C>A (rs6721961) in the healthy population was 12.8%. SNPs were in Hardy-Weinberg equilibrium (p>0.05). Gender-based differences were not observed with the studied SNP in the healthy population and the lung cancer patients. These frequencies of NRF2 were found to be similar when compared to EUR (European) and all the South Asian subpopulations. They are significantly divergent compared to AFR (African), AMR (American), and EAS (East Asian) populations. The minor allele frequency in cancer patients was found to be 14.2% and the lung cancer risk with the SNP studied could not be detected. There was no association found with the response, toxicity, and survival among lung cancer patients.

CONCLUSION

NRF2, being a multifaced molecule, did not show a significant association with lung cancer risk, response, and toxicity in patients with gemcitabine-based chemotherapy.

Redox-Regulated Iron Metabolism and Ferroptosis in Ovarian Cancer: Molecular Insights and Therapeutic Opportunities

Ovarian cancer (OC), known for its lethality and resistance to chemotherapy, is closely associated with iron metabolism and ferroptosis-an iron-dependent cell death process, distinct from both autophagy and apoptosis. Emerging evidence suggests that dysregulation of iron metabolism could play a crucial role in OC by inducing an imbalance in the redox system, which leads to ferroptosis, offering a novel therapeutic approach. This review examines how disruptions in iron metabolism, which affect redox balance, impact OC progression, focusing on its essential cellular functions and potential as a therapeutic target. It highlights the molecular interplay, including the role of non-coding RNAs (ncRNAs), between iron metabolism and ferroptosis, and explores their interactions with key immune cells such as macrophages and T cells, as well as inflammation within the tumor microenvironment. The review also discusses how glycolysis-related iron metabolism influences ferroptosis via reactive oxygen species. Targeting these pathways, especially through agents that modulate iron metabolism and ferroptosis, presents promising therapeutic prospects. The review emphasizes the need for deeper insights into iron metabolism and ferroptosis within the redox-regulated system to enhance OC therapy and advocates for continued research into these mechanisms as potential strategies to combat OC.

Recent Advances in the Inhibition of Membrane Lipid Peroxidation by Food-Borne Plant Polyphenols via the Nrf2/GPx4 Pathway

Lipid peroxidation (LP) leads to changes in the fluidity and permeability of cell membranes, affecting normal cellular function and potentially triggering apoptosis or necrosis. This process is closely correlated with the onset of many diseases. Evidence suggests that the phenolic hydroxyl groups in food-borne plant polyphenols (FPPs) make them effective antioxidants capable of preventing diseases triggered by cell membrane LP. Proper dietary intake of FPPs can attenuate cellular oxidative stress, especially damage to cell membrane phospholipids, by activating the Nrf2/GPx4 pathway. Nuclear factor E2-related factor 2 (Nrf2) is an oxidative stress antagonist. The signaling pathway regulated by Nrf2 is a defense transduction pathway of the organism against external stimuli such as reactive oxygen species and exogenous chemicals. Glutathione peroxidase 4 (GPx4), under the regulation of Nrf2, is the only enzyme that reduces cell membrane lipid peroxides with specificity, thus playing a pivotal role in regulating cellular ferroptosis and counteracting oxidative stress. This study explored the Nrf2/GPx4 pathway mechanism, antioxidant activity of FPPs, and mechanism of LP. It also highlighted the bioprotective properties of FPPs against LP and its associated mechanisms, including (i) activation of the Nrf2/GPx4 pathway, with GPx4 potentially serving as a central target protein, (ii) regulation of antioxidant enzyme activities, leading to a reduction in the production of ROS and other peroxides, and (iii) antioxidant effects on LP and downstream phospholipid structure. In conclusion, FPPs play a crucial role as natural antioxidants in preventing LP. However, further in-depth analysis of FPPs coregulation of multiple signaling pathways is required, and the combined effects of these mechanisms need further evaluation in experimental models. Human trials could provide valuable insights into new directions for research and application.

PPIA dictates NRF2 stability to promote lung cancer progression

Nuclear factor erythroid 2-related factor 2 (NRF2) hyperactivation has been established as an oncogenic driver in a variety of human cancers, including non-small cell lung cancer (NSCLC). However, despite massive efforts, no specific therapy is currently available to target NRF2 hyperactivation. Here, we identify peptidylprolyl isomerase A (PPIA) is required for NRF2 protein stability. Ablation of PPIA promotes NRF2 protein degradation and blocks NRF2-driven growth in NSCLC cells. Mechanistically, PPIA physically binds to NRF2 and blocks the access of ubiquitin/Kelch Like ECH Associated Protein 1 (KEAP1) to NRF2, thus preventing ubiquitin-mediated degradation. Our X-ray co-crystal structure reveals that PPIA directly interacts with a NRF2 interdomain linker via a trans-proline 174-harboring hydrophobic sequence. We further demonstrate that an FDA-approved drug, cyclosporin A (CsA), impairs the interaction of NRF2 with PPIA, inducing NRF2 ubiquitination and degradation. Interestingly, CsA interrupts glutamine metabolism mediated by the NRF2/KLF5/SLC1A5 pathway, consequently suppressing the growth of NRF2-hyperactivated NSCLC cells. CsA and a glutaminase inhibitor combination therapy significantly retard tumor progression in NSCLC patient-derived xenograft (PDX) models with NRF2 hyperactivation. Our study demonstrates that targeting NRF2 protein stability is an actionable therapeutic approach to treat NRF2-hyperactivated NSCLC.

TBHQ Alleviates Particulate Matter-Induced Pyroptosis in Human Nasal Epithelial Cells

Pyroptosis represents a type of cell death mechanism notable for its cell membrane disruption and the subsequent release of proinflammatory cytokines. The Nod-like receptor family pyrin domain containing inflammasome 3 (NLRP3) plays a critical role in the pyroptosis mechanism associated with various diseases resulting from particulate matter (PM) exposure. Tert-butylhydroquinone (tBHQ) is a synthetic antioxidant commonly used in a variety of foods and products. The aim of this study is to examine the potential of tBHQ as a therapeutic agent for managing sinonasal diseases induced by PM exposure. The occurrence of NLRP3 inflammasome-dependent pyroptosis in RPMI 2650 cells treated with PM < 4 µm in size was confirmed using Western blot analysis and enzyme-linked immunosorbent assay results for the pyroptosis metabolites IL-1β and IL-18. In addition, the inhibitory effect of tBHQ on PM-induced pyroptosis was confirmed using Western blot and immunofluorescence techniques. The inhibition of tBHQ-mediated pyroptosis was abolished upon nuclear factor erythroid 2-related factor 2 (Nrf2) knockdown, indicating its involvement in the antioxidant mechanism. tBHQ showed potential as a therapeutic agent for sinonasal diseases induced by PM because NLRP3 inflammasome activation was effectively suppressed via the Nrf2 pathway.

Hypoxia in uterine fibroids: role in pathobiology and therapeutic opportunities

Uterine fibroids are the most common tumors in females affecting up to 70% of women world-wide, yet targeted therapeutic options are limited. Oxidative stress has recently surfaced as a key driver of fibroid pathogenesis and provides insights into hypoxia-induced cell transformation, extracellular matrix pathophysiology, hypoxic cell signaling cascades, and uterine biology. Hypoxia drives fibroid tumorigenesis through (1) promoting myometrial stem cell proliferation, (2) causing DNA damage propelling transformation of stem cells to tumor initiating cells, and (3) driving excess extracellular matrix (ECM) production. Common fibroid-associated DNA mutations include MED12 mutations, HMGA2 overexpression, and Fumarate hydratase loss of function. Evidence suggests an interaction between hypoxia signaling and these mutations. Fibroid development and growth are promoted by hypoxia-triggered cell signaling via various pathways including HIF-1, TGFβ, and Wnt/β-catenin. Fibroid-associated hypoxia persists due to antioxidant imbalance, ECM accumulation, and growth beyond adequate vascular supply. Current clinically available fibroid treatments do not take advantage of hypoxia-targeting therapies. Growing pre-clinical and clinical studies identify ROS inhibitors, anti-HIF-1 agents, Wnt/β-catenin inhibition, and TGFβ cascade inhibitors as agents that may reduce fibroid development and growth through targeting hypoxia.

Ferroptosis, pyroptosis and necroptosis in hepatocellular carcinoma immunotherapy: Mechanisms and immunologic landscape (Review)

Hepatocellular carcinoma (HCC), one of the leading causes of cancer‑related mortality worldwide, is challenging to identify in its early stages and prone to metastasis, and the prognosis of patients with this disease is poor. Treatment options for HCC are limited, with even radical treatments being associated with a risk of recurrence or transformation in the short term. Furthermore, the multi‑tyrosine kinase inhibitors approved for first‑line therapy have marked drawbacks, including drug resistance and side effects. The rise and breakthrough of immune checkpoint inhibitors (ICIs) have provided a novel direction for HCC immunotherapy but these have the drawback of low response rates. Since avoiding apoptosis is a universal feature of cancer, the induction of non‑apoptotic regulatory cell death (NARCD) is a novel strategy for HCC immunotherapy. At present, NARCD pathways, including ferroptosis, pyroptosis and necroptosis, are novel potential forms of immunogenic cell death, which have synergistic effects with antitumor immunity, transforming immune 'cold' tumors into immune 'hot' tumors and exerting antitumor effects. Therefore, these pathways may be targeted as a novel treatment strategy for HCC. In the present review, the roles of ferroptosis, pyroptosis and necroptosis in antitumor immunity in HCC are discussed, and the relevant targets and signaling pathways, and the current status of combined therapy with ICIs are summarized. The prospects of targeting ferroptosis, pyroptosis and necroptosis in HCC immunotherapy are also considered.

Glutathione metabolism-related gene signature predicts prognosis and treatment response in low-grade glioma

Cancer cells can induce molecular changes that reshape cellular metabolism, creating specific vulnerabilities for targeted therapeutic interventions. Given the importance of reactive oxygen species (ROS) in tumor development and drug resistance, and the abundance of reduced glutathione (GSH) as the primary cellular antioxidant, we examined an integrated panel of 56 glutathione metabolism-related genes (GMRGs) across diverse cancer types. This analysis revealed a remarkable association between GMRGs and low-grade glioma (LGG) survival. Unsupervised clustering and a GMRGs-based risk score (GS) categorized LGG patients into two groups, linking elevated glutathione metabolism to poorer prognosis and treatment outcomes. Our GS model outperformed established clinical prognostic factors, acting as an independent prognostic factor. GS also exhibited correlations with pro-tumor M2 macrophage infiltration, upregulated immunosuppressive genes, and diminished responses to various cancer therapies. Experimental validation in glioma cell lines confirmed the critical role of glutathione metabolism in glioma cell proliferation and chemoresistance. Our findings highlight the presence of a unique metabolic susceptibility in LGG and introduce a novel GS system as a highly effective tool for predicting the prognosis of LGG.

Reappraisal of the Roles of the Sonic Hedgehog Signaling Pathway in Hepatocellular Carcinoma

HCC remains one of the leading causes of cancer-related death globally. The main challenges in treatments of hepatocellular carcinoma (HCC) primarily arise from high rates of postoperative recurrence and the limited efficacy in treating advanced-stage patients. Various signaling pathways involved in HCC have been reported. Among them, the Sonic hedgehog (SHH) signaling pathway is crucial. The presence of SHH ligands is identified in approximately 60% of HCC tumor tissues, including tumor nests. PTCH-1 and GLI-1 are detected in more than half of HCC tissues, while GLI-2 is found in over 84% of HCC tissues. The SHH signaling pathway (including canonical and non-canonical) is involved in different aspects of HCC, including hepatocarcinogenesis, tumor growth, tumor invasiveness, progression, and migration. The SHH signaling pathway also contributes to recurrence, metastasis, modulation of the cancer microenvironment, and sustaining cancer stem cells. It also affects the resistance of HCC cells to chemotherapy, target therapy, and radiotherapy. Reappraisal of the roles of the SHH signaling pathway in HCC may trigger some novel therapies for HCC.

Natural products as non-covalent and covalent modulators of the KEAP1/NRF2 pathway exerting antioxidant effects

By controlling several antioxidant and detoxifying genes at the transcriptional level, including NAD(P)H quinone oxidoreductase 1 (NQO1), multidrug resistance-associated proteins (MRPs), UDP-glucuronosyltransferase (UGT), glutamate-cysteine ligase catalytic (GCLC) and modifier (GCLM) subunits, glutathione S-transferase (GST), sulfiredoxin1 (SRXN1), and heme-oxygenase-1 (HMOX1), the KEAP1/NRF2 pathway plays a crucial role in the oxidative stress response. Accordingly, the discovery of modulators of this pathway, activating cellular signaling through NRF2, and targeting the antioxidant response element (ARE) genes is pivotal for the development of effective antioxidant agents. In this context, natural products could represent promising drug candidates for supplementation to provide antioxidant capacity to human cells. In recent decades, by coupling in silico and experimental methods, several natural products have been characterized to exert antioxidant effects by targeting the KEAP1/NRF2 pathway. In this review article, we analyze several natural products that were investigated experimentally and in silico for their ability to modulate KEAP1/NRF2 by non-covalent and covalent mechanisms. These latter represent the two main sections of this article. For each class of inhibitors, we reviewed their antioxidant effects and potential therapeutic applications, and where possible, we analyzed the structure-activity relationship (SAR). Moreover, the main computational techniques used for the most promising identified compounds are detailed in this survey, providing an updated view on the development of natural products as antioxidant agents.

The Experimental and In Silico-Based Evaluation of NRF2 Modulators, Sulforaphane and Brusatol, on the Transcriptome of Immortalized Bovine Mammary Alveolar Cells

Changes during the production cycle of dairy cattle can leave these animals susceptible to oxidative stress and reduced antioxidant health. In particular, the periparturient period, when dairy cows must rapidly adapt to the sudden metabolic demands of lactation, is a period when the production of damaging free radicals can overwhelm the natural antioxidant systems, potentially leading to tissue damage and reduced milk production. Central to the protection against free radical damage and antioxidant defense is the transcription factor NRF2, which activates an array of genes associated with antioxidant functions and cell survival. The objective of this study was to evaluate the effect that two natural NRF2 modulators, the NRF2 agonist sulforaphane (SFN) and the antagonist brusatol (BRU), have on the transcriptome of immortalized bovine mammary alveolar cells (MACT) using both the RT-qPCR of putative NRF2 target genes, as well as RNA sequencing approaches. The treatment of cells with SFN resulted in the activation of many putative NRF2 target genes and the upregulation of genes associated with pathways involved in cell survival, metabolism, and antioxidant function while suppressing the expression of genes related to cellular senescence and DNA repair. In contrast, the treatment of cells with BRU resulted in the upregulation of genes associated with inflammation, cellular stress, and apoptosis while suppressing the transcription of genes involved in various metabolic processes. The analysis also revealed several novel putative NRF2 target genes in bovine. In conclusion, these data indicate that the treatment of cells with SFN and BRU may be effective at modulating the NRF2 transcriptional network, but additional effects associated with cellular stress and metabolism may complicate the effectiveness of these compounds to improve antioxidant health in dairy cattle via nutrigenomic approaches.

Keap1-Nrf2 pathway: a key mechanism in the occurrence and development of cancer

The Keap1-Nrf2 signaling pathway is a major regulator of the cytoprotective response, participating in endogenous and exogenous stress caused by ROS (reactive oxygen species). Nrf2 is the core of this pathway. We summarized the literature on Keap1-Nrf2 signaling pathway and summarized the following three aspects: structure, function pathway, and cancer and clinical application status. This signaling pathway is similar to a double-edged sword: on the one hand, Nrf2 activity can protect cells from oxidative and electrophilic stress; on the other hand, increasing Nrf2 activity can enhance the survival and proliferation of cancer cells. Notably, oxidative stress is also considered a marker of cancer in humans. Keap1-Nrf2 signaling pathway, as a typical antioxidant stress pathway, is abnormal in a variety of human malignant tumor diseases (such as lung cancer, liver cancer, and thyroid cancer). In recent years, research on the Keap1-Nrf2 signaling pathway has become increasingly in-depth and detailed. Therefore, it is of great significance for cancer prevention and treatment to explore the molecular mechanism of the occurrence and development of this pathway.

Iron, Copper, and Selenium: Cancer's Thing for Redox Bling

Cells require micronutrients for numerous basic functions. Among these, iron, copper, and selenium are particularly critical for redox metabolism, and their importance is heightened during oncogene-driven perturbations in cancer. In this review, which particularly focuses on iron, we describe how these micronutrients are carefully chaperoned about the body and made available to tissues, a process that is designed to limit the toxicity of free iron and copper or by-products of selenium metabolism. We delineate perturbations in iron metabolism and iron-dependent proteins that are observed in cancer, and describe the current approaches being used to target iron metabolism and iron-dependent processes.

Reassessing the role of phytochemicals in cancer chemoprevention

In this comprehensive review we tried to reassess the role of phytochemicals in cancer chemoprevention. The exploration of the "synergistic effect" concept, advocating combined chemopreventive agents, faces challenges like low bioavailability. The review incorporates personal, occasionally controversial, viewpoints on natural compounds' cancer preventive capabilities, delving into mechanisms. Prioritizing significant contributions within the vast research domain, we aim stimulating discussion to provide a comprehensive insight into the evolving role of phytochemicals in cancer prevention. While early years downplayed the role of phytochemicals, the late nineties witnessed a shift, with leaders exploring their potential alongside synthetic compounds. Challenges faced by chemoprevention, such as limited pharmaceutical interest and cost-effectiveness issues, persist despite successful drugs. Recent studies, including the EPIC study, provide nuanced insights, indicating a modest risk reduction for increased fruit and vegetable intake. Phytochemicals, once attributed to antioxidant effects, face scrutiny due to low bioavailability and conflicting evidence. The Nrf2-EpRE signaling pathway and microbiota-mediated metabolism emerge as potential mechanisms, highlighting the complexity of understanding phytochemical mechanisms in cancer chemoprevention.

Autism spectrum disorder: pathogenesis, biomarker, and intervention therapy

Autism spectrum disorder (ASD) has become a common neurodevelopmental disorder. The heterogeneity of ASD poses great challenges for its research and clinical translation. On the basis of reviewing the heterogeneity of ASD, this review systematically summarized the current status and progress of pathogenesis, diagnostic markers, and interventions for ASD. We provided an overview of the ASD molecular mechanisms identified by multi-omics studies and convergent mechanism in different genetic backgrounds. The comorbidities, mechanisms associated with important physiological and metabolic abnormalities (i.e., inflammation, immunity, oxidative stress, and mitochondrial dysfunction), and gut microbial disorder in ASD were reviewed. The non-targeted omics and targeting studies of diagnostic markers for ASD were also reviewed. Moreover, we summarized the progress and methods of behavioral and educational interventions, intervention methods related to technological devices, and research on medical interventions and potential drug targets. This review highlighted the application of high-throughput omics methods in ASD research and emphasized the importance of seeking homogeneity from heterogeneity and exploring the convergence of disease mechanisms, biomarkers, and intervention approaches, and proposes that taking into account individuality and commonality may be the key to achieve accurate diagnosis and treatment of ASD.

Nrf2 protein in melanoma progression, as a new means of treatment

Melanoma is a potentially lethal form of skin cancer resulting from the unlimited proliferation of melanocytes. Melanocytic lineage appears to have a greater rate of reactive oxygen species (ROS) production, possibly as a result of exposure to ultraviolet (UV) light and the production of melanin. It has been established that nuclear factor erythroid 2-related factor 2 (Nrf2) serves as a master regulator of the cellular response to oxidative stresses. Recent research has shown that the Nrf2 and its critical negative regulator Kelch-like ECH-associated protein 1 (Keap1) are misregulated in melanoma, and the Keap1-Nrf2 pathway has emerged as a promising new target for treating and preventing melanoma. In melanoma, Nrf2 may either limit tumor growth or promote its development. This review covers a wide range of topics, including the dual functions played by the Keap1-Nrf2 signaling pathway in melanoma and the most recent targeting techniques of the Nrf2.

Regulation of Nrf2/Keap1 signaling pathway in cancer drug resistance by galectin-1: cellular and molecular implications

Oxidative stress is characterized by the deregulation of the redox state in the cells, which plays a role in the initiation of various types of cancers. The activity of galectin-1 (Gal-1) depends on the cell redox state and the redox state of the microenvironment. Gal-1 expression has been related to many different tumor types, as it plays important roles in several processes involved in cancer progression, such as apoptosis, cell migration, adhesion, and immune response. The erythroid-2-related factor 2 (Nrf2)/Kelch-like ECH-associated protein 1 (Keap1) signaling pathway is a crucial mechanism involved in both cell survival and cell defense against oxidative stress. In this review, we delve into the cellular and molecular roles played by Gal-1 in the context of oxidative stress onset in cancer cells, particularly focusing on its involvement in activating the Nrf2/Keap1 signaling pathway. The emerging evidence concerning the anti-apoptotic effect of Gal-1, together with its ability to sustain the activation of the Nrf2 pathway in counteracting oxidative stress, supports the role of Gal-1 in the promotion of tumor cells proliferation, immuno-suppression, and anti-tumor drug resistance, thus highlighting that the inhibition of Gal-1 emerges as a potential strategy for the restraint and regression of tumor progression. Overall, a deeper understanding of the multi-functionality and disease-specific expression profiling of Gal-1 will be crucial for the design and development of novel Gal-1 inhibitors as anticancer agents. Excitingly, although it is still understudied, the ever-growing knowledge of the sophisticated interplay between Gal-1 and Nrf2/Keap1 will enable researchers to gain valuable insights into the underlying causes of carcinogenesis and metastasis.

The influence of Nrf2 gene promoter methylation on gene expression and oxidative stress parameters in preeclampsia

BACKGROUND AND AIMS

Preeclampsia (PE) is a serious medical condition that usually causes high blood pressure and affects multiple organs. Considering the adverse effect of oxidative stress on the process of PE in pregnant women and regarding the role of the Nrf2 gene in placental oxidative pathways, this study was conducted to investigate the DNA methylation status of Nrf2 in PE and healthy pregnant women.

MATERIALS AND METHODS

The present case-control study consisted of 70 PE and 70 healthy pregnant women. Blood and placenta samples were taken from all subjects, and the percentage of the Nrf2 gene methylation in the samples was assessed by the Methyl Light PCR method. Also, the Nrf2 gene expression was evaluated by real-time PCR. The total antioxidant capacity (TAC) and total oxidative status (TOS) were measured by the colorimetric method.

RESULTS

In PE women, there was a significant increase in blood pressure, term of pregnancy, and BMI. In addition, there were enhanced Nrf2 DNA methylation percentage in placenta tissue and increased TOS levels in placenta tissue and blood compared to healthy pregnant women (P < 0.05). Also, in the PE group, there was a significant decrease in Nrf2 gene expression and TAC level in placenta tissue compared to the control group (P < 0.05).

CONCLUSION

The Nrf2 gene undergoes epigenetic modifications of DNA hypermethylation in the PE placenta. Decreased expression of this gene and the changes in the level of oxidative parameters (TAC, TOS) confirm it.

Pharmacological activation of nuclear factor erythroid 2-related factor-2 prevents hyperglycemia-induced renal oxidative damage: Possible involvement of O-GlcNAcylation

Hyperglycemia is a major risk factor for kidney diseases. Oxidative stress, caused by reactive oxygen species, is a key factor in the development of kidney abnormalities related to hyperglycemia. The nuclear factor erythroid 2-related factor-2 (Nrf2) plays a crucial role in defending cells against oxidative stress by activating genes that produce antioxidants. L-sulforaphane (SFN), a drug that activates Nrf2, reduces damage caused by hyperglycemia. Hyperglycemic Wistar rats and HEK 293 cells maintained in hyperglycemic medium exhibited decreased Nrf2 nuclear translocation and reduced expression and activity of antioxidant enzymes. SFN treatment increased Nrf2 activity and reversed decreased renal function, oxidative stress and cell death associated with hyperglycemia. To investigate mechanisms involved in hyperglycemia-induced reduced Nrf2 activity, we addressed whether Nrf2 is modified by O-linked β-N-acetylglucosamine (O-GlcNAc), a post-translational modification that is fueled in hyperglycemic conditions. In vivo, hyperglycemia increased O-GlcNAc-modified Nrf2 expression. Increased O-GlcNAc levels, induced by pharmacological inhibition of OGA, decreased Nrf2 activity in HEK 293 cells. In conclusion, hyperglycemia reduces Nrf2 activity, promoting oxidative stress, cell apoptosis and structural and functional renal damage. Pharmacological treatment with SFN attenuates renal injury. O-GlcNAcylation negatively modulates Nrf2 activity and represents a potential mechanism leading to oxidative stress and renal damage in hyperglycemic conditions.

4-octyl itaconate inhibits high glucose induced renal tubular epithelial cell fibrosis through TGF-β-ROS pathway

Diabetic kidney disease (DKD) is one of the most serious complications of diabetes and has become the leading cause of end-stage kidney disease, causing serious health damage and a huge economic burden. Tubulointerstitial fibrosis play important role in the development of DKD. Itaconate, a macrophage-specific metabolite, has been reported to have anti-oxidant, anti-inflammatory effects. However, it is unknown whether it perform anti-fibrotic effect in renal tubular epithelial cells. In this current study, we observed that in human renal tubular epithelial cells (HK2), high glucose induced an increase in transforming growth factor β (TGF-β) production, and upregulated the expressions of fibronectin and collagen I through the TGF-β receptor as verified by administration of TGF-β receptor blocker LY2109761. Treatment with 4-octyl itaconate (4-OI), a derivant of itaconic acid, reduced the TGF-β production induced by high glucose and inhibited the pro-fibrotic effect of TGF-β in a dose-dependent manner. In addition, we found that 4-OI exerted its anti-fibrotic effect by inhibiting the excessive production of ROS induced by high glucose and TGF-β. In summary, 4-OI could ameliorate high glucose-induced pro-fibrotic effect in HK2 cell, and blocking the expression of TGF-β and reducing the excessive ROS production may be involved in its anti-fibrotic effect.

Selection of GalNAc-Conjugated siKeap1 as Disease-Specific Delivery System for Chemotherapy-Induced Liver Injury and Chronic Liver Disease

Chemotherapy-induced liver injury (CILI) is a pressing concern in cancer patients. One promising approach involves activating nuclear factor erythroid 2-related factor 2 (Nrf2) to mitigate CILI. However, selectively activating liver Nrf2 without compromising chemotherapy's efficacy has remained elusive. Herein, two RNAi delivery strategies were explored: lipid nanoparticle (LNP) and N-acetylgalactosamine (GalNAc) delivery systems loaded with siRNA designed to silence Kelch-like-ECH associated protein 1 (Keap1) by aiming for liver-specific Nrf2 activation. Remarkably, siKeap1-LNP exhibited unintended tumor targeting alongside liver effects, thereby potentially promoting tumor progression. Conversely, siKeap1-GalNAc did not compromise chemotherapy efficacy and outperformed the conventional Nrf2 activator, bardoxolone, in mitigating CILI. This study proposes siKeap1-GalNAc as a promising therapeutic avenue for liver injury. Importantly, our study bridges a crucial gap concerning the delivery system for liver targeting but not tumor targeting and underscores the importance of selecting nucleic acid delivery systems tailored to specific diseases, not just to specific organs.

Iron accumulation and lipid peroxidation: implication of ferroptosis in hepatocellular carcinoma

Ferroptosis is a type of controlled cell death caused by lipid peroxidation, which results in the rupture of the cell membrane. ferroptosis has been repeatedly demonstrated over the past ten years to be a significant factor in a number of diseases. The liver is a significant iron storage organ, thus ferroptosis will have great potential in the treatment of liver diseases. Ferroptosis is particularly prevalent in HCC. In the opening section of this article, we give a general summary of the pertinent molecular mechanisms, signaling pathways, and associated characteristics of ferroptosis. The primary regulating mechanisms during ferroptosis are then briefly discussed, and we conclude by summarizing the development of a number of novel therapeutic strategies used to treat HCC in recent years. Ferroptosis is a crucial strategy for the treatment of HCC and offers new perspectives on the treatment of liver cancer.

The Multifaceted Roles of NRF2 in Cancer: Friend or Foe?

Physiological concentrations of reactive oxygen species (ROS) play vital roles in various normal cellular processes, whereas excessive ROS generation is central to disease pathogenesis. The nuclear factor erythroid 2-related factor 2 (NRF2) is a critical transcription factor that regulates the cellular antioxidant systems in response to oxidative stress by governing the expression of genes encoding antioxidant enzymes that shield cells from diverse oxidative alterations. NRF2 and its negative regulator Kelch-like ECH-associated protein 1 (KEAP1) have been the focus of numerous investigations in elucidating whether NRF2 suppresses tumor promotion or conversely exerts pro-oncogenic effects. NRF2 has been found to participate in various pathological processes, including dysregulated cell proliferation, metabolic remodeling, and resistance to apoptosis. Herein, this review article will examine the intriguing role of phase separation in activating the NRF2 transcriptional activity and explore the NRF2 dual impacts on tumor immunology, cancer stem cells, metastasis, and long non-coding RNAs (LncRNAs). Taken together, this review aims to discuss the NRF2 multifaceted roles in both cancer prevention and promotion while also addressing the advantages, disadvantages, and limitations associated with modulating NRF2 therapeutically in cancer treatment.

Advances on the Role of Ferroptosis in Ionizing Radiation Response

Ferroptosis is an iron-dependent programmed cell death mode that is distinct from other cell death modes, and radiation is able to stimulate cellular oxidative stress and induce the production of large amounts of reactive oxygen radicals, which in turn leads to the accumulation of lipid peroxide and the onset of ferroptosis. In this review, from the perspective of the role of ferroptosis in generating a radiation response following cellular irradiation, the relationship between ferroptosis induced by ionizing radiation stress and the response to ionizing radiation is reviewed, including the roles of MAPK and Nrf2 signaling pathways in ferroptosis, resulting from the oxidative stress response to ionizing radiation, the metabolic regulatory role of the p53 gene in ferroptosis, and regulatory modes of action of iron metabolism and iron metabolism-related regulatory proteins in promoting and inhibiting ferroptosis. It provides some ideas for the follow-up research to explore the specific mechanism and regulatory network of ferroptosis in response to ionizing radiation.

Examining hepatoprotective effects of astaxanthin against methotrexate-induced hepatotoxicity in rats through modulation of Nrf2/HO-1 pathway genes

Methotrexate (MTX), as a folic acid antagonist, is an effective drug in treating a wide range of malignancies and autoimmune diseases. However, the clinical use of MTX has been limited due to its side effects, the most common of which is hepatotoxicity. In this study, rats were randomly divided into six groups: three treatment groups received methotrexate and different doses of astaxanthin (AX) for 14 days. At the end of the study, blood samples were collected to determine serum levels of ALT, AST, ALP, and LDH. Also, liver tissues were isolated to evaluate antioxidant enzymes and markers of oxidative stress, histopathological damage, and expression of NF-E2-related transcription factor (Nrf2) and Heme oxygenase-1 (HO-1) genes. The results showed that administration of MTX significantly increased the levels of ALT, AST, ALP, and LDH in the blood, markers of oxidative stress, and histopathological damage in liver tissue and significantly reduced the levels of antioxidant enzymes and the expression of Nrf2 and HO-1 genes. On the other hand, treatment with AX decreased blood levels of ALT, AST, ALP, and LDH and oxidative stress markers and remarkably raises the activity of antioxidant enzymes and expression of Nrf2 and HO-1 genes in liver tissue. In addition, histopathological lesions were improved with AX administration. The findings of this study indicated that AX may be useful for the prevention of MTX-induced hepatotoxicity by improving oxidative and inflammatory changes.

NRF2 promotes radiation resistance by cooperating with TOPBP1 to activate the ATR-CHK1 signaling pathway

Background: Radiation resistance is the main limitation of the application of radiotherapy. Ionizing radiation (IR) kills cancer cells mainly by causing DNA damage, particularly double-strand breaks (DSBs). Radioresistant cancer cells have developed the robust capability of DNA damage repair to survive IR. Nuclear factor erythroid 2-related factor 2 (NRF2) has been correlated with radiation resistance. We previously reported a novel function of NRF2 as an ATR activator in response to DSBs. However, little is known about the mechanism that how NRF2 regulates DNA damage repair and radiation resistance. Methods: The TCGA database and tissue microarray were used to analyze the correlation between NRF2 and the prognosis of lung cancer patients. The radioresistant lung cancer cells were constructed, and the role of NRF2 in radiation resistance was explored by in vivo and in vitro experiments. Immunoprecipitation, immunofluorescence and extraction of chromatin fractions were used to explore the underlying mechanisms. Results: In this study, the TCGA database and clinical lung cancer samples showed that high expression of NRF2 was associated with poor prognosis in lung cancer patients. We established radioresistant lung cancer cells expressing NRF2 at high levels, which showed increased antioxidant and DNA repair abilities. In addition, we found that NRF2 can be involved in the DNA damage response independently of its antioxidant function. Mechanistically, we demonstrated that NRF2 promoted the phosphorylation of replication protein A 32 (RPA32), and DNA topoisomerase 2-binding protein 1 (TOPBP1) was recruited to DSB sites in an NRF2-dependent manner. Conclusion: This study explored the novel role of NRF2 in promoting radiation resistance by cooperating with RPA32 and TOPBP1 to activate the ATR-CHK1 signaling pathway. In addition, the findings of this study not only provide novel insights into the molecular mechanisms underlying the radiation resistance of lung cancer cells but also validate NRF2 as a potential target for radiotherapy.

FOXO transcription factors as mediators of stress adaptation

The forkhead box protein O (FOXO, consisting of FOXO1, FOXO3, FOXO4 and FOXO6) transcription factors are the mammalian orthologues of Caenorhabditis elegans DAF-16, which gained notoriety for its capability to double lifespan in the absence of daf-2 (the gene encoding the worm insulin receptor homologue). Since then, research has provided many mechanistic details on FOXO regulation and FOXO activity. Furthermore, conditional knockout experiments have provided a wealth of data as to how FOXOs control development and homeostasis at the organ and organism levels. The lifespan-extending capabilities of DAF-16/FOXO are highly correlated with their ability to induce stress response pathways. Exogenous and endogenous stress, such as cellular redox stress, are considered the main drivers of the functional decline that characterizes ageing. Functional decline often manifests as disease, and decrease in FOXO activity indeed negatively impacts on major age-related diseases such as cancer and diabetes. In this context, the main function of FOXOs is considered to preserve cellular and organismal homeostasis, through regulation of stress response pathways. Paradoxically, the same FOXO-mediated responses can also aid the survival of dysfunctional cells once these eventually emerge. This general property to control stress responses may underlie the complex and less-evident roles of FOXOs in human lifespan as opposed to model organisms such as C. elegans.

Nrf2, A Target for Precision Oncology in Cancer Prognosis and Treatment

Activating nuclear factor-erythroid 2-related factor (Nrf2), a master regulator of redox homeostasis, has been shown to suppress initiation of carcinogenesis in normal cells. However, this transcription factor has recently been reported to promote proliferation of some transformed or cancerous cells. In tumor cells, Nrf2 is prone to mutations that result in stabilization and concurrent accumulation of its protein product. A hyperactivated mutant form of Nrf2 could support the cancer cells for enhanced proliferation, invasiveness, and resistance to chemotherapeutic agents and radiotherapy, which are associated with a poor clinical outcome. Hence understanding mutations in Nrf2 would have a significant impact on the prognosis and treatment of cancer in the era of precision medicine. This perspective would provide an insight into the genetic alterations in Nrf2 and suggest the application of small molecules, RNAi, and genome editing technologies, particularly CRISR-Cas9, in therapeutic intervention of cancer in the context of the involvement of Nrf2 mutations.

Localization, tissue biology and T cell state - implications for cancer immunotherapy

Tissue localization is a critical determinant of T cell immunity. CD8+ T cells are contact-dependent killers, which requires them to physically be within the tissue of interest to kill peptide-MHC class I-bearing target cells. Following their migration and extravasation into tissues, T cells receive many extrinsic cues from the local microenvironment, and these signals shape T cell differentiation, fate and function. Because major organ systems are variable in their functions and compositions, they apply disparate pressures on T cells to adapt to the local microenvironment. Additional complexity arises in the context of malignant lesions (either primary or metastatic), and this has made understanding the factors that dictate T cell function and longevity in tumours challenging. Moreover, T cell differentiation state influences how cues from the microenvironment are interpreted by tissue-infiltrating T cells, highlighting the importance of T cell state in the context of tissue biology. Here, we review the intertwined nature of T cell differentiation state, location, survival and function, and explain how dysfunctional T cell populations can adopt features of tissue-resident memory T cells to persist in tumours. Finally, we discuss how these factors have shaped responses to cancer immunotherapy.

A state-of-the-art review on the NRF2 in Hepatitis virus-associated liver cancer

According to a paper released and submitted to WHO by IARC scientists, there would be 905,700 new cases of liver cancer diagnosed globally in 2020, with 830,200 deaths expected as a direct result. Hepatitis B virus (HBV) hepatitis C virus (HCV), and hepatitis D virus (HDV) all play critical roles in the pathogenesis of hepatocellular carcinoma (HCC), despite the rising prevalence of HCC due to non-infectious causes. Liver cirrhosis and HCC are devastating consequences of HBV and HCV infections, which are widespread worldwide. Associated with a high mortality rate, these infections cause about 1.3 million deaths annually and are the primary cause of HCC globally. In addition to causing insertional mutations due to viral gene integration, epigenetic alterations and inducing chronic immunological dysfunction are all methods by which these viruses turn hepatocytes into cancerous ones. While expanding our knowledge of the illness, identifying these pathways also give possibilities for novel diagnostic and treatment methods. Nuclear factor erythroid 2-related factor 2 (NRF2) activation is gaining popularity as a treatment option for oxidative stress (OS), inflammation, and metabolic abnormalities. Numerous studies have shown that elevated Nrf2 expression is linked to HCC, providing more evidence that Nrf2 is a critical factor in HCC. This aberrant Nrf2 signaling drives cell proliferation, initiates angiogenesis and invasion, and imparts drug resistance. As a result, this master regulator may be a promising treatment target for HCC. In addition, the activation of Nrf2 is a common viral effect that contributes to the pathogenesis, development, and chronicity of virus infection. However, certain viruses suppress Nrf2 activity, which is helpful to the virus in maintaining cellular homeostasis. In this paper, we discussed the influence of Nrf2 deregulation on the viral life cycle and the pathogenesis associated with HBV and HCV. We summed up the mechanisms for the modulation of Nrf2 that are deregulated by these viruses. Moreover, we describe the molecular mechanism by which Nrf2 is modulated in liver cancer, liver cancer stem cells (LCSCs), and liver cancer caused by HBV and HCV. Video Abstract.

NRF3 suppresses squamous carcinogenesis, involving the unfolded protein response regulator HSPA5

Epithelial skin cancers are extremely common, but the mechanisms underlying their malignant progression are still poorly defined. Here, we identify the NRF3 transcription factor as a tumor suppressor in the skin. NRF3 protein expression is strongly downregulated or even absent in invasively growing cancer cells of patients with basal and squamous cell carcinomas (BCC and SCC). NRF3 deficiency promoted malignant conversion of chemically induced skin tumors in immunocompetent mice, clonogenic growth and migration of human SCC cells, their invasiveness in 3D cultures, and xenograft tumor formation. Mechanistically, the tumor-suppressive effect of NRF3 involves HSPA5, a key regulator of the unfolded protein response, which we identified as a potential NRF3 interactor. HSPA5 levels increased in the absence of NRF3, thereby promoting cancer cell survival and migration. Pharmacological inhibition or knock-down of HSPA5 rescued the malignant features of NRF3-deficient SCC cells in vitro and in preclinical mouse models. Together with the strong expression of HSPA5 in NRF3-deficient cancer cells of SCC patients, these results suggest HSPA5 inhibition as a treatment strategy for these malignancies in stratified cancer patients.

Critical role of heme oxygenase-1 in chaetoglobosin A by triggering reactive oxygen species mediated mitochondrial apoptosis in colorectal cancer

The incidence rate of colorectal cancer (CRC) has been increasing and poses severe threats to human health worldwide and developing effective treatment strategies remains an urgent task. In this study, Chaetoglobosin A (ChA), an endophytic fungal metabolite from the medicinal herb-derived fungus Chaetomium globosum Km1126, was identified as a potent and selective antitumor agent in human CRC. ChA induced growth inhibition of CRC cells in a concentration-dependent manner but did not impair the viability of normal colon cells. ChA triggered mitochondrial intrinsic and caspase-dependent apoptotic cell death. In addition, apoptosis antibody array analysis revealed that expression of Heme oxygenase-1 (HO-1) was significantly increased by ChA. Inhibition of HO-1 increased the sensitivity of CRC cells to ChA, suggesting HO-1 may play a protective role in ChA-mediated cell death. ChA induced cell apoptosis via the induction of reactive oxygen species (ROS) and ROS scavenger (NAC) prevented ChA-induced cell death, mitochondrial dysfunction, and HO-1 activation. ChA promoted the activation of c-Jun N-terminal kinase (JNK), and co-administration of JNK inhibitor or siRNA markedly reversed ChA-mediated apoptosis. ChA significantly decreased the tumor growth without eliciting any organ toxicity or affecting the body weight of the CRC xenograft mice. This is the first study to demonstrate that ChA exhibits promising anti-cancer properties against human CRC both in vitro and in vivo. ChA is a potential therapeutic agent worthy of further development in clinical trials for cancer treatment.

Synthesis of Quinazolin-2,4,6-triamine Derivatives as Non-purine Xanthine Oxidase Inhibitors and Exploration of Their Toxicological Potential

In this work, a new set of quinazolin-2,4,6-triamine derivatives were synthesized to explore their potential biological activity as xanthine oxidase (XO) inhibitors, superoxide scavengers and screening of their toxicological profile. Among all the synthesized compounds, B1 exhibited better inhibitory activity against bovine xanthine oxidase (bXO) than allopurinol (IC50 =1.56 μM and IC50 =6.99 μM, respectively). As superoxide scavengers, B1, B2 and B13 exhibited a better effect than allopurinol (97.3 %, 82.1 %, 87.4 % and 69.4 %, respectively). Regarding the toxicological profile, B1 was less cytotoxic than methotrexate on HCT-15 cancer cells. Apoptosis results obtained in cells of female and male mice, showed that B1 and B2 presented a similar behaviour to CrO3 (positive control) with respect to the average frequency to induce apoptosis; while B13 apoptosis induced effect was similar to DMSO and control group. Finally, B1, B2, B13 did not induce genotoxicity in a micronuclei murine model compared to CrO3 .

Primary Prevention and Interception Studies in RAS-Mutated Tumor Models Employing Small Molecules or Vaccines

Therapeutic targeting of RAS-mutated cancers is difficult, whereas prevention or interception (treatment before or in the presence of preinvasive lesions) preclinically has proven easier. In the A/J mouse lung model, where different carcinogens induce tumors with different KRAS mutations, glucocorticoids and retinoid X receptor (RXR) agonists are effective agents in prevention and interception studies, irrespective of specific KRAS mutations. In rat azoxymethane-induced colon tumors (45% KRAS mutations), cyclooxygenase 1/2 inhibitors and difluoromethylornithine are effective in preventing or intercepting KRAS-mutated or wild-type tumors. In two KRAS-mutant pancreatic models multiple COX 1/2 inhibitors are effective. Furthermore, combining a COX and an EGFR inhibitor prevented the development of virtually all pancreatic tumors in transgenic mice. In the N-nitroso-N-methylurea-induced estrogen receptor-positive rat breast model (50% HRAS mutations) various selective estrogen receptor modulators, aromatase inhibitors, EGFR inhibitors, and RXR agonists are profoundly effective in prevention and interception of tumors with wild-type or mutant HRAS, while the farnesyltransferase inhibitor tipifarnib preferentially inhibits HRAS-mutant breast tumors. Thus, many agents not known to specifically inhibit the RAS pathway, are effective in an organ specific manner in preventing or intercepting RAS-mutated tumors. Finally, we discuss an alternative prevention and interception approach, employing vaccines to target KRAS.

Neurotoxicity of 4-nonylphenol in adult zebrafish: Evaluation of behaviour, oxidative stress parameters and histopathology of brain

Nonylphenol and its derivatives use as plasticizer or additives in manufacturing industries. Effluents originated from industrial areas are being added to soil, ground water, river and marine water intentionally or unintentionally. Complex mixture of these contaminants enter the food chain and produce sub-lethal deleterious effects mainly on nervous and reproductive systems of aquatic animals and human beings. The information pertaining to oxidative stress-mediated alterations in brain of zebrafish would be helpful to understand the toxicity potential of such compounds in aquatic animals. The aim of the present study was to evaluate the behavioural changes, status of oxidative stress markers; sod, cat, and NF-E2-related factor 2 (nrf2) mRNA gene expression profile; and histopathological changes in the brain of adult zebrafish exposed to 4-nonylphenol (4NP) at concentration of 100 and 200 μg/L of water for 21 days. Zebrafish were divided into four groups viz; control (C1), vehicle (C2, ethanol 10 μg/L of water), treatment 1 (T1, 4-NP, 100 μg/L) and treatment 2 (T2, 4-NP, 200 μg/L). Both exposure levels of 4-NP adversely affected the exploratory behaviour of zebrafish and produced anxiety-like symptom. Concentration-dependent reduction in activity of superoxide dismutase and catalase; and glutathione level, with increased level of malondialdehyde recorded in the brain of exposed zebrafish. Gene expression analysis showed down regulation of sod, cat, nrf2 genes in brain of zebrafish from toxicity groups indicating 4-NP induced oxidative stress in brain. However, noticeable histological alterations were not observed in 4-NP exposed brain of zebrafish.

Identification of structurally diverse FSP1 inhibitors that sensitize cancer cells to ferroptosis

Ferroptosis is a regulated form of cell death associated with the iron-dependent accumulation of phospholipid hydroperoxides. Inducing ferroptosis is a promising approach to treat therapy-resistant cancer. Ferroptosis suppressor protein 1 (FSP1) promotes ferroptosis resistance in cancer by generating the antioxidant form of coenzyme Q10 (CoQ). Despite the important role of FSP1, few molecular tools exist that target the CoQ-FSP1 pathway. Through a series of chemical screens, we identify several structurally diverse FSP1 inhibitors. The most potent of these compounds, ferroptosis sensitizer 1 (FSEN1), is an uncompetitive inhibitor that acts selectively through on-target inhibition of FSP1 to sensitize cancer cells to ferroptosis. Furthermore, a synthetic lethality screen reveals that FSEN1 synergizes with endoperoxide-containing ferroptosis inducers, including dihydroartemisinin, to trigger ferroptosis. These results provide new tools that catalyze the exploration of FSP1 as a therapeutic target and highlight the value of combinatorial therapeutic regimes targeting FSP1 and additional ferroptosis defense pathways.

Insight into Nrf2: a bibliometric and visual analysis from 2000 to 2022

Background: Nrf2 plays a pivotal role in governing the antioxidant defense system, triggering the transcription of diverse genes involved in cellular protection. Its role in mitigating oxidative damage and modulating inflammatory processes has made Nrf2 an attractive target for therapeutic interventions. Despite the growing interest in Nrf2 research, a bibliometric analysis is relatively rare. This study aimed to clarify Nrf2's role in multiple diseases, identify emerging trends and hotspots using bibliometric analysis, and provide valuable insights and potential directions for future therapeutic interventions. Methods: The Science Citation Index of Web of Science Core library from 2000 to 2022 was searched on 22 October 2022. Use Microsoft Excel, CiteSpace, Bibliometrix, and VOS viewers for data collection and visualization of research focus and trends. Results: A vast collection of 22,040 research studies on Nrf2 published between 2000 and 2022 were identified. Nrf2 research has seen significant growth globally from 2000 to 2022. China leaded in publication numbers (9,623, 43.66%), while the United States dominated in citation frequency with 261,776 citations. China Medical University was the most productive institutions (459, 2.08%). Masayuki Yamamoto topped in publications (307), while Itoh K. ranked first in citations with 3669. Free Radical Biology and Medicine was the journal with the most studies and citations on Nrf2 (613, 29,687 citations). The analysis of keyword clustering enhanced the categorization of topics and can be summarized as oxidative stress, cancer, disorders in glycolipid metabolism, inflammation, and neurological conditions. Conclusion: China and the United States are the pioneers in Nrf2 research. Recently, there has been a comprehensive exploration of Nrf2 involving both experimental and clinical aspects, as well as mechanisms and therapeutic applications. Investigating novel molecular mechanisms, including NF-κB, Ho1, and Keap1, and developing enhanced, targeted Nrf2 activators or inhibitors to uncover the interplay among cancer, glycolipid metabolic disorder, inflammation, and neurological disorders will be upcoming trends and hotspots.

Redox Regulation of Nrf2 in Cisplatin-Induced Kidney Injury

Cisplatin, a potent chemotherapeutic agent, is marred by severe nephrotoxicity that is governed by mechanisms involving oxidative stress, inflammation, and apoptosis pathways. The transcription factor Nrf2, pivotal in cellular defense against oxidative stress and inflammation, is the master regulator of the antioxidant response, upregulating antioxidants and cytoprotective genes under oxidative stress. This review discusses the mechanisms underlying chemotherapy-induced kidney injury, focusing on the role of Nrf2 in cancer therapy and its redox regulation in cisplatin-induced kidney injury. We also explore Nrf2's signaling pathways, post-translational modifications, and its involvement in autophagy, as well as examine redox-based strategies for modulating Nrf2 in cisplatin-induced kidney injury while considering the limitations and potential off-target effects of Nrf2 modulation. Understanding the redox regulation of Nrf2 in cisplatin-induced kidney injury holds significant promise for developing novel therapeutic interventions. This knowledge could provide valuable insights into potential strategies for mitigating the nephrotoxicity associated with cisplatin, ultimately enhancing the safety and efficacy of cancer treatment.

(-)-Epicatechin Inhibits Metastatic-Associated Proliferation, Migration, and Invasion of Murine Breast Cancer Cells In Vitro

Breast cancer, due to its high incidence and mortality, is a public health problem worldwide. Current chemotherapy uses non-specific cytotoxic drugs, which inhibit tumor growth but cause significant adverse effects. (-)-Epicatechin (EC) is part of a large family of biomolecules called flavonoids. It is widely distributed in the plant kingdom; it can be found in green tea, grapes, and cocoa. Several studies in animals and humans have shown that EC induces beneficial effects in the skeletal muscle and the cardiovascular system, reducing risk factors such as arterial hypertension, endothelial dysfunction, damage to skeletal muscle structure, and mitochondrial malfunction by promoting mitochondrial biogenesis, with no adverse effects reported. Recently, we reported that EC had an antitumor effect in a murine triple-negative mammary gland tumor model, decreasing tumoral size and volume and increasing survival by 44%. This work aimed to characterize the effects of flavanol EC on proliferation, migration, and metastasis markers of triple-negative murine breast (4T1) cancer cells in culture. We found proliferation diminished and Bax/Bcl2 ratio increased. When the migration of culture cells was evaluated, we observed a significant reduction in migration. Also, the relative expression of the genes associated with metastasis, Cdh1, Mtss1, Pten, Bmrs, Fat1, and Smad4, was increased. In conclusion, these results contribute to understanding molecular mechanisms activated by EC that can inhibit metastatic-associated proliferation, migration, and invasion of murine breast cancer cells.

B7-H3 confers stemness characteristics to gastric cancer cells by promoting glutathione metabolism through AKT/pAKT/Nrf2 pathway

BACKGROUND

Cancer stem-like cells (CSCs) are a small subset of cells in tumors that exhibit self-renewal and differentiation properties. CSCs play a vital role in tumor formation, progression, relapse, and therapeutic resistance. B7-H3, an immunoregulatory protein, has many protumor functions. However, little is known about the mechanism underlying the role of B7-H3 in regulating gastric cancer (GC) stemness. Our study aimed to explore the impacts of B7-H3 on GC stemness and its underlying mechanism.

METHODS

GC stemness influenced by B7-H3 was detected both in vitro and in vivo . The expression of stemness-related markers was examined by reverse transcription quantitative polymerase chain reaction, Western blotting, and flow cytometry. Sphere formation assay was used to detect the sphere-forming ability. The underlying regulatory mechanism of B7-H3 on the stemness of GC was investigated by mass spectrometry and subsequent validation experiments. The signaling pathway (Protein kinase B [Akt]/Nuclear factor erythroid 2-related factor 2 [Nrf2] pathway) of B7-H3 on the regulation of glutathione (GSH) metabolism was examined by Western blotting assay. Multi-color immunohistochemistry (mIHC) was used to detect the expression of B7-H3, cluster of differentiation 44 (CD44), and Nrf2 on human GC tissues. Student's t -test was used to compare the difference between two groups. Pearson correlation analysis was used to analyze the relationship between two molecules. The Kaplan-Meier method was used for survival analysis.

RESULTS

B7-H3 knockdown suppressed the stemness of GC cells both in vitro and in vivo . Mass spectrometric analysis showed the downregulation of GSH metabolism in short hairpin B7-H3 GC cells, which was further confirmed by the experimental results. Meanwhile, stemness characteristics in B7-H3 overexpressing cells were suppressed after the inhibition of GSH metabolism. Furthermore, Western blotting suggested that B7-H3-induced activation of GSH metabolism occurred through the AKT/Nrf2 pathway, and inhibition of AKT signaling pathway could suppress not only GSH metabolism but also GC stemness. mIHC showed that B7-H3 was highly expressed in GC tissues and was positively correlated with the expression of CD44 and Nrf2. Importantly, GC patients with high expression of B7-H3, CD44, and Nrf2 had worse prognosis ( P = 0.02).

CONCLUSIONS

B7-H3 has a regulatory effect on GC stemness and the regulatory effect is achieved through the AKT/Nrf2/GSH pathway. Inhibiting B7-H3 expression may be a new therapeutic strategy against GC.

The mechanistic insights of the antioxidant Keap1-Nrf2 pathway in oncogenesis: a deadly scenario

The Nuclear factor erythroid 2-related factor 2 (Nrf2) protein has garnered significant interest due to its crucial function in safeguarding cells and tissues. The Nrf2 protein is crucial in preserving tissue integrity by safeguarding cells against metabolic, xenobiotic and oxidative stress. Due to its various functions, Nrf2 is a potential pharmacological target for reducing the incidence of diseases such as cancer. However, mutations in Keap1-Nrf2 are not consistently favored in all types of cancer. Instead, they seem to interact with specific driver mutations of tumors and their respective tissue origins. The Kelch-like ECH-associated protein 1 (Keap1)-Nrf2 pathway mutations are a powerful cancer adaptation that utilizes inherent cytoprotective pathways, encompassing nutrient metabolism and ROS regulation. The augmentation of Nrf2 activity elicits significant alterations in the characteristics of neoplastic cells, such as resistance to radiotherapy and chemotherapy, safeguarding against apoptosis, heightened invasiveness, hindered senescence, impaired autophagy and increased angiogenesis. The altered activity of Nrf2 can arise from diverse genetic and epigenetic modifications that instantly impact Nrf2 regulation. The present study aims to showcase the correlation between the Keap1-Nrf2 pathway and the progression of cancers, emphasizing genetic mutations, metabolic processes, immune regulation, and potential therapeutic strategies. This article delves into the intricacies of Nrf2 pathway anomalies in cancer, the potential ramifications of uncontrolled Nrf2 activity, and therapeutic interventions to modulate the Keap1-Nrf2 pathway.

S-Glutathionylation and S-Nitrosylation as Modulators of Redox-Dependent Processes in Cancer Cell

Development of oxidative/nitrosative stress associated with the activation of oncogenic pathways results from the increase in the generation of reactive oxygen and nitrogen species (ROS/RNS) in tumor cells, where they can have a dual effect. At high concentrations, ROS/RNS cause cell death and limit tumor growth at certain phases of its development, while their low amounts promote oxidative/nitrosative modifications of key redox-dependent residues in regulatory proteins. The reversibility of such modifications as S-glutathionylation and S-nitrosylation that proceed through the electrophilic attack of ROS/RNS on nucleophilic Cys residues ensures the redox-dependent switch in the activity of signaling proteins, as well as the ability of these compounds to control cell proliferation and programmed cell death. The content of S-glutathionylated and S-nitrosylated proteins is controlled by the balance between S-glutathionylation/deglutathionylation and S-nitrosylation/denitrosylation, respectively, and depends on the cellular redox status. The extent of S-glutathionylation and S-nitrosylation of protein targets and their ratio largely determine the status and direction of signaling pathways in cancer cells. The review discusses the features of S-glutathionylation and S-nitrosylation reactions and systems that control them in cancer cells, as well as their relationship with redox-dependent processes and tumor growth.

A potent phosphodiester Keap1-Nrf2 protein-protein interaction inhibitor as the efficient treatment of Alzheimer's disease

The Keap1-Nrf2 pathway has been established as a therapeutic target for Alzheimer's disease (AD). Directly inhibiting the protein-protein interaction (PPI) between Keap1 and Nrf2 has been reported as an effective strategy for treating AD. Our group has validated this in an AD mouse model for the first time using the inhibitor 1,4-diaminonaphthalene NXPZ-2 with high concentrations. In the present study, we reported a new phosphodiester containing diaminonaphthalene compound, POZL, designed to target the PPI interface using a structure-based design strategy to combat oxidative stress in AD pathogenesis. Our crystallographic verification confirms that POZL shows potent Keap1-Nrf2 inhibition. Remarkably, POZL showed its high in vivo anti-AD efficacy at a much lower dosage compared to NXPZ-2 in the transgenic APP/PS1 AD mouse model. POZL treatment in the transgenic mice could effectively ameliorate learning and memory dysfunction by promoting the Nrf2 nuclear translocation. As a result, the oxidative stress and AD biomarker expression such as BACE1 and hyperphosphorylation of Tau were significantly reduced, and the synaptic function was recovered. HE and Nissl staining confirmed that POZL improved brain tissue pathological changes by enhancing neuron quantity and function. Furthermore, it was confirmed that POZL could effectively reverse Aβ-caused synaptic damage by activating Nrf2 in primary cultured cortical neurons. Collectively, our findings demonstrated that the phosphodiester diaminonaphthalene Keap1-Nrf2 PPI inhibitor could be regarded as a promising preclinical candidate of AD.

Identification of NRF2 Activation as a Prognostic Biomarker in T-Cell Acute Lymphoblastic Leukaemia

The standard-of-care treatment of T-cell acute lymphoblastic leukaemia (T-ALL) with chemotherapy usually achieves reasonable rates of initial complete response. However, patients who relapse or do not respond to conventional therapy show dismal outcomes, with cure rates below 10% and limited therapeutic options. To ameliorate the clinical management of these patients, it is urgent to identify biomarkers able to predict their outcomes. In this work, we investigate whether NRF2 activation constitutes a biomarker with prognostic value in T-ALL. Using transcriptomic, genomic, and clinical data, we found that T-ALL patients with high NFE2L2 levels had shorter overall survival. Our results demonstrate that the PI3K-AKT-mTOR pathway is involved in the oncogenic signalling induced by NRF2 in T-ALL. Furthermore, T-ALL patients with high NFE2L2 levels displayed genetic programs of drug resistance that may be provided by NRF2-induced biosynthesis of glutathione. Altogether, our results indicate that high levels of NFE2L2 may be a predictive biomarker of poor treatment response in T-ALL patients, which would explain the poor prognosis associated with these patients. This enhanced understanding of NRF2 biology in T-ALL may allow a more refined stratification of patients and the proposal of targeted therapies, with the ultimate goal of improving the outcome of relapsed/refractory T-ALL patients.

Donafenib and GSK-J4 Synergistically Induce Ferroptosis in Liver Cancer by Upregulating HMOX1 Expression

Hepatocellular carcinoma (HCC) is one of the most lethal cancers worldwide. Donafenib is a multi-receptor tyrosine kinase inhibitor approved for the treatment of patients with advanced HCC, but its clinical effect is very limited. Here, through integrated screening of a small-molecule inhibitor library and a druggable CRISPR library, that GSK-J4 is synthetically lethal with donafenib in liver cancer is shown. This synergistic lethality is validated in multiple HCC models, including xenograft, orthotopically induced HCC, patient-derived xenograft, and organoid models. Furthermore, co-treatment with donafenib and GSK-J4 resulted in cell death mainly via ferroptosis. Mechanistically, through integrated RNA sequencing (RNA-seq) and assay for transposase-accessible chromatin with high throughput sequencing (ATAC-seq) analyses, that donafenib and GSK-J4 synergistically promoted the expression of HMOX1 and increased the intracellular Fe2+ level is found, eventually leading to ferroptosis. Additionally, through cleavage under targets & tagmentation followed by sequencing (CUT&Tag-seq), it is found that the enhancer regions upstream of HMOX1 promoter significantly increased under donafenib and GSK-J4 co-treatment. A chromosome conformation capture assay confirmed that the increased expression of HMOX1 is caused by the significantly enhanced interaction between the promoter and upstream enhancer under dual-drug combination. Taken together, this study elucidates a new synergistic lethal interaction in liver cancer.