Dual roles of Nrf2 in cancer

Molecular basis of the interactions between the disordered Neh4 and Neh5 domains of Nrf2 and CBP/p300 in oxidative stress response

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a major transcription factor that functions in maintaining redox homeostasis in cells. It mediates the transcription of cytoprotective genes in response to environmental and endogenous stresses to prevent oxidative damage. Thus, Nrf2 plays a significant role in chemoprevention. However, aberrant activation of Nrf2 has been shown to protect cancer cells from apoptosis and contribute to their chemoresistance. The interaction between Nrf2 and CBP is critical for the gene transcription activation. CBP and its homologue p300 interact with two transactivation domains in Nrf2, Neh4, and Neh5 domains through their TAZ1 and TAZ2 domains. To date, the molecular basis of this crucial interaction is not known, hindering a more detailed understanding of the regulation of Nrf2. To close this knowledge gap, we have used a set of biophysical experiments to dissect the Nrf2-CBP/p300 interactions. Structural properties of Neh4 and Neh5 and their binding with the TAZ1 and TAZ2 domains of CBP/p300 were characterized. Our results show that the Neh4 and Neh5 domains of Nrf2 are intrinsically disordered, and they both can bind the TAZ1 and TAZ2 domains of CBP/p300 with micromolar affinities. The findings provide molecular insight into the regulation of Nrf2 by CBP/p300 through multi-domain interactions.

Endoplasmic reticulum stress and quality control in relation to cisplatin resistance in tumor cells

The endoplasmic reticulum (ER) is a crucial organelle that orchestrates key cellular functions like protein folding and lipid biosynthesis. However, it is highly sensitive to disturbances that lead to ER stress. In response, the unfolded protein response (UPR) activates to restore ER homeostasis, primarily through three sensors: IRE1, ATF6, and PERK. ERAD and autophagy are crucial in mitigating ER stress, yet their dysregulation can lead to the accumulation of misfolded proteins. Cisplatin, a commonly used chemotherapy drug, induces ER stress in tumor cells, activating complex signaling pathways. Resistance to cisplatin stems from reduced drug accumulation, activation of DNA repair, and anti-apoptotic mechanisms. Notably, cisplatin-induced ER stress can dualistically affect tumor cells, promoting either survival or apoptosis, depending on the context. ERAD is crucial for degrading misfolded proteins, whereas autophagy can protect cells from apoptosis or enhance ER stress-induced apoptosis. The complex interaction between ER stress, cisplatin resistance, ERAD, and autophagy opens new avenues for cancer treatment. Understanding these processes could lead to innovative strategies that overcome chemoresistance, potentially improving outcomes of cisplatin-based cancer treatments. This comprehensive review provides a multifaceted perspective on the complex mechanisms of ER stress, cisplatin resistance, and their implications in cancer therapy.

Sexual dimorphism in colorectal cancer: molecular mechanisms and treatment strategies

INTRODUCTION

Sexual dimorphism significantly influences cancer incidence and prognosis. Notably, females exhibit a lower risk and favorable prognosis for non-reproductive cancers compared to males, a pattern observable beyond the scope of risk behaviors such as alcohol consumption and smoking. Colorectal cancer, ranking third in global prevalence and second in mortality, disproportionately affects men. Sex steroid hormones, particularly estrogens and androgens, play crucial roles in cancer progression, considering epidemiological in vivo and in vitro, in general estrogens imparting a protective effect in females and androgens correlating with an increasing risk of colorectal cancer development.

MAIN BODY

The hormonal impact on immune response is mediated by receptor interactions, resulting in heightened inflammation, modulation of NF-kB, and fostering an environment conducive to cancer progression and metastasis. These molecules also influence the enteric nervous system, that is a pivotal in neuromodulator release and intestinal neuron stimulation, also contributes to cancer development, as evidenced by nerve infiltration into tumors. Microbiota diversity further intersects with immune, hormonal, and neural mechanisms, influencing colorectal cancer dynamics. A comprehensive understanding of hormonal influences on colorectal cancer progression, coupled with the complex interplay between immune responses, microbiota diversity and neurotransmitter imbalances, underpins the development of more targeted and effective therapies.

CONCLUSIONS

Estrogens mitigate colorectal cancer risk by modulating anti-tumor immune responses, enhancing microbial diversity, and curbing the pro-tumor actions of the sympathetic and enteric nervous systems. Conversely, androgens escalate tumor growth by dampening anti-tumor immune activity, reducing microbial diversity, and facilitating the release of tumor-promoting factors by the nervous system. These findings hold significant potential for the strategic purposing of drugs to fine-tune the extensive impacts of sex hormones within the tumor microenvironment, promising advancements in colorectal cancer therapies.

Carbamate compounds induced toxic effects by affecting Nrf2 signaling pathways

Carbamate (CBs) is a class of insecticides which is being known as an important cause of intentional or accidental poisoning. CBs, cause carbamylation of acetylcholinesterase at neuronal synapses and neuromuscular junction. Exposure to CBs through skin contact, inhalation, or ingestion can result in significant cholinergic toxicity. This is due to the elevation of acetylcholine levels at ganglionic synapses found in both the sympathetic and parasympathetic nervous systems, as well as muscarinic receptors located in target organs of the parasympathetic nervous system, nicotinic receptors situated in skeletal muscle tissue, and the central nervous system. The association between human illnesses and environmental exposures to CBs have been extensively studied in several studies. Although CBs-triggered toxicity leads to overproduction of reactive oxygen species (ROS), the detailed association between the toxicity under CBs exposure and NFE2-related factor 2 (Nrf2) signaling pathways has not been completely clarified. In this review we aimed to summarize the latest findings on the functional interrelationship between carbamates compounds and Nrf2 signaling.

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.

Modifying Effects of Genetic Variations on the Association Between Dietary Isothiocyanate Exposure and Non-muscle Invasive Bladder Cancer Prognosis in the Be-Well Study

SCOPE

Dietary isothiocyanate (ITC) exposure from cruciferous vegetable (CV) intake may improve non-muscle invasive bladder cancer (NMIBC) prognosis. This study aims to investigate whether genetic variations in key ITC-metabolizing/functioning genes modify the associations between dietary ITC exposure and NMIBC prognosis outcomes.

METHODS AND RESULTS

In the Bladder Cancer Epidemiology, Wellness, and Lifestyle Study (Be-Well Study), a prospective cohort of 1472 incident NMIBC patients, dietary ITC exposure is assessed by self-reported CV intake and measured in plasma ITC-albumin adducts. Using Cox proportional hazards regression models, stratified by single nucleotide polymorphisms (SNPs) in nine key ITC-metabolizing/functioning genes, it is calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for recurrence and progression. The rs15561 in N-acetyltransferase 1 (NAT1) is alter the association between CV intake and progression risk. Multiple SNPs in nuclear factor E2-related factor 2 (NRF2) and nuclear factor kappa B (NFκB) are modify the associations between plasma ITC-albumin adduct level and progression risk (pint < 0.05). No significant association is observed with recurrence risk. Overall, >80% study participants are present with at least one protective genotype per gene, showing an average 65% reduction in progression risk with high dietary ITC exposure.

CONCLUSION

Despite that genetic variations in ITC-metabolizing/functioning genes may modify the effect of dietary ITCs on NMIBC prognosis, dietary recommendation of CV consumption may help improve NMIBC survivorship.

Potential Role of Nrf2, HER2, and ALDH in Cancer Stem Cells: A Narrative Review

Cancer is one of the main causes of death among humans, second only to cardiovascular diseases. In recent years, numerous studies have been conducted on the pathophysiology of cancer, and it has been established that this disease is developed by a group of stem cells known as cancer stem cells (CSCs). Thus, cancer is considered a stem cell disease; however, there is no comprehensive consensus about the characteristics of these cells. Several different signaling pathways including Notch, Hedgehog, transforming growth factor-β (TGF-β), and WNT/β-catenin pathways cause the self-renewal of CSCs. CSCs change their metabolic pathways in order to access easy energy. Therefore, one of the key objectives of researchers in cancer treatment is to destroy CSCs. Nuclear factor erythroid 2-related factor 2 (Nrf2) plays an essential role in the protection of CSCs from reactive oxygen species (ROS) and chemotherapeutic agents by regulating antioxidants and detoxification enzymes. Human epidermal growth factor receptor 2 (HER2) is a member of the tyrosine kinase receptor family, which contributes to the protection of cancer cells against treatment and implicated in the invasion, epithelial-mesenchymal transition (EMT), and tumorigenesis. Aldehyde dehydrogenases (ALDHs) are highly active in CSCs and protect the cells against damage caused by active aldehydes through the regulation of aldehyde metabolism. On the other hand, ALDHs promote the formation and maintenance of tumor cells and lead to drug resistance in tumors through the activation of various signaling pathways, such as the ALDH1A1/HIF-1α/VEGF axis and Wnt/β-catenin, as well as changing the intracellular pH value. Given the growing body of information in this field, in the present narrative review, we attempted to shed light on the function of Nrf2, HER2, and ALDH in CSCs.

Effect of Pyridoxine Derivative B6NO on Transcription Factor Nrf2 Activity and Cytotoxic Properties of Doxorubicin In Vitro

The effect of a new pyridoxine derivative B6NO on doxorubicin cytotoxicity and Nrf2-dependent cellular processes in vitro was studied. Antioxidant B6NO enhances the cytotoxic effect of doxorubicin on tumor cells, which is associated with G2/M cell division arrest and an increase in activity of proapoptotic enzyme caspase-3. The antioxidant promotes intracellular accumulation and nuclear translocation of Nrf2 transcription factor in non-tumor and tumor cells. In non-tumor cells, B6NO increases the expression of antioxidant system proteins and reduces ROS generation in the presence of doxorubicin. In tumor cells, no activation of Nrf2-dependent processes occurs under the action of the antioxidant. Our findings demonstrate the prospect of further studies of pyridoxine derivatives as antioxidants to reduce adverse reactions during chemotherapy.

GDF15 induces chemoresistance to oxaliplatin by forming a reciprocal feedback loop with Nrf2 to maintain redox homeostasis in colorectal cancer

PURPOSE

Growth differentiating Factor 15 (GDF15) is linked to several cancers, but its effect on chemoresistance in colorectal cancer (CRC) remains unclear. Here, we investigated the role of GDF15 in the chemotherapeutic response of CRC patients to oxaliplatin (L-OHP).

METHODS

GDF15 levels in serum and tumour tissues were detected in CRC patients have received L-OHP-based neoadjuvant chemotherapy. The effects of GDF15 neutralization or GDF15 knockdown on cell proliferation, apoptosis and intracellular reactive oxygen species (ROS) levels were analysed in vitro and in vivo. Co-immunoprecipitation (Co-IP), Chromatin Immunoprecipitation (ChIP) and luciferase reporter assays were used to explore the interaction between GDF15 and Nrf2.

RESULTS

In this study, we found that GDF15 alleviates oxidative stress to induce chemoresistance of L-OHP in CRC. Mechanically, GDF15 posttranscriptionally regulates protein stability of Nrf2 through the canonical PI3K/AKT/GSK3β signaling pathway, and in turn, Nrf2 acts as a transcription factor to regulate GDF15 expression to form a positive feedback loop, resulting in the maintenance of redox homeostasis balance in CRC. Furthermore, a positive correlation between GDF15 and Nrf2 was observed in clinical CRC samples, and simultaneous overexpression of both GDF15 and Nrf2 was associated with poor prognosis in CRC patients treated with L-OHP. Simultaneous inhibition of both GDF15 and Nrf2 significantly increases the response to L-OHP in an L-OHP-resistant colorectal cancer cells-derived mouse xenograft model.

CONCLUSION

This study identified a novel GDF15-Nrf2 positive feedback loop that drives L-OHP resistance and suggested that the GDF15-Nrf2 axis is a potential therapeutic target for the treatment of L-OHP-resistant CRC.

Ochratoxin A promotes chronic enteritis and early colorectal cancer progression by targeting Rinck signaling

BACKGROUND

Mycotoxins, such as aflatoxin and ochratoxin A (OTA), are found at measurable levels in many staple foods; the health implications of long-term exposure of such toxins are poorly understood. Increasing evidence has confirmed the important role of OTA in upregulation of oxidative stress- and inflammatory response-induced tissue injury. However, it remains unknown whether ochratoxin A can promote chronic colitis and its associated colon cancer (CRC) development, and potential molecular mechanism. Additionally, RING finger-interacting protein with C kinase (RINCK) is a ubiquitin ligase and mediates immune response. Unfortunately, the potential molecular function of RINCK on regulation of colitis is still largely unknown.

PURPOSE

This study aims to provide mechanistic evidence that the role of RINCK in colitis and early colorectal cancer progression in response to OTA treatment via targeting nuclear factor erythroid 2-related factor 2 (NRF2).

METHODS

The Cancer Genome Atlas (TCGA) database, GEO database, human subjects with CC phenotype and CC cell lines were used in this work. Pathological links between OTA, RINCK and treatment of CC are revealed through comprehensive means such as biological information analysis, clinical experiments, RNA-seq, and verification experiments.

RESULTS

In this study, under oxidative stress in setting of colitis, we first identified RINCK as a key regulatory factor and a novel endogenous suppressor of nuclear factor erythroid 2-related factor 2 (NRF2), and we also confirm that RINCK is a NRF2 partner protein that catalyses its ubiquitination and degradation in intestinal epithelial cells (IECs). Notably, in vivo study, pathological phenotypes triggered by OTA pretreatment, accompanied by post-treatment of dextran sulfate sodium (DSS)-induced colitis was significantly mitigated by IEC-specific deficiency of Rinck, IEC-Rinck(KO) and adenovirus-associated virus (AAV)-triggered suppression of Rinck in rodent model, and lentivirus (LV)-mediated downregulation of Rinck (LV-shRinck) in rabbit model, as determined by decreased endogenous reactive oxygen species (ROS) production, pro-inflammatory cytokines contents, improved body weights, reduced survival rates, restored colon length, assuasive DAI and histological scores. Inversely, transgenic mice by IEC-specific Rinck overexpression, IEC-Rinck(OE) accelerated colitis in acute or chronic colitis rodent models and in vitro experiments. Moreover, we found that OTA pretreatment-promoted azoxymethane (AOM)/DSS-induced colitis-associated early colorectal cancer (CRC) was also dramatically reduced by IEC-Rinck(KO), indicated by the decreased tumor number and corresponding KI-67 levels. Clinical samples analysis revealed that RINCK levels were greatly increased in tumor tissues of patients with CRC phenotypes. In parallel, RINCK deletion remarkably retarded the proliferation of colon cancer and tumor growth in vitro and in vivo, respectively. Mechanistically, in response to onset of colitis, RINCK directly interacts with NRF2 and promotes ubiquitin-proteasome degradation via increasing K48-linkage ubiquitin chain, thus leads in suppression of NRF2 nuclear translocation and its downstream cascade inactivation, which retards antioxidant defense.

CONCLUSION

The findings suggested that oral sub-chronic exposure of OTA significantly facilitates DSS-induced colitis and colitis-associated CRC development. These results further elucidated the potential role of RINCK in colitis progression by mediating NRF2 degradation, and could be considered as a therapeutic target for the treatment of such disease.

Exploring the multifaceted role of NRF2 in brain physiology and cancer: A comprehensive review

Chronic oxidative stress plays a critical role in the development of brain malignancies due to the high rate of brain oxygen utilization and concomitant production of reactive oxygen species. The nuclear factor-erythroid-2-related factor 2 (NRF2), a master regulator of antioxidant signaling, is a key factor in regulating brain physiology and the development of age-related neurodegenerative diseases. Also, NRF2 is known to exert a protective antioxidant effect against the onset of oxidative stress-induced diseases, including cancer, along with its pro-oncogenic activities through regulating various signaling pathways and downstream target genes. In glioblastoma (GB), grade 4 glioma, tumor resistance, and recurrence are caused by the glioblastoma stem cell population constituting a small bulk of the tumor core. The persistence and self-renewal capacity of these cell populations is enhanced by NRF2 expression in GB tissues. This review outlines NRF2's dual involvement in cancer and highlights its regulatory role in human brain physiology and diseases, in addition to the development of primary brain tumors and therapeutic potential, with a focus on GB.

Transcription Factor NRF2 in Shaping Myeloid Cell Differentiation and Function

NFE2-related factor 2 (NRF2) is a master transcription factor (TF) that coordinates key cellular homeostatic processes including antioxidative responses, autophagy, proteostasis, and metabolism. The emerging evidence underscores its significant role in modulating inflammatory and immune processes. This chapter delves into the role of NRF2 in myeloid cell differentiation and function and its implication in myeloid cell-driven diseases. In macrophages, NRF2 modulates cytokine production, phagocytosis, pathogen clearance, and metabolic adaptations. In dendritic cells (DCs), it affects maturation, cytokine production, and antigen presentation capabilities, while in neutrophils, NRF2 is involved in activation, migration, cytokine production, and NETosis. The discussion extends to how NRF2's regulatory actions pertain to a wide array of diseases, such as sepsis, various infectious diseases, cancer, wound healing, atherosclerosis, hemolytic conditions, pulmonary disorders, hemorrhagic events, and autoimmune diseases. The activation of NRF2 typically reduces inflammation, thereby modifying disease outcomes. This highlights the therapeutic potential of NRF2 modulation in treating myeloid cell-driven pathologies.

The Role of the NRF2 Pathway in the Pathogenesis of Viral Respiratory Infections

In humans, acute and chronic respiratory infections caused by viruses are associated with considerable morbidity and mortality. Respiratory viruses infect airway epithelial cells and induce oxidative stress, yet the exact pathogenesis remains unclear. Oxidative stress activates the transcription factor NRF2, which plays a key role in alleviating redox-induced cellular injury. The transcriptional activation of NRF2 has been reported to affect both viral replication and associated inflammation pathways. There is complex bidirectional crosstalk between virus replication and the NRF2 pathway because virus replication directly or indirectly regulates NRF2 expression, and NRF2 activation can reversely hamper viral replication and viral spread across cells and tissues. In this review, we discuss the complex role of the NRF2 pathway in the regulation of the pathogenesis of the main respiratory viruses, including coronaviruses, influenza viruses, respiratory syncytial virus (RSV), and rhinoviruses. We also summarize the scientific evidence regarding the effects of the known NRF2 agonists that can be utilized to alter the NRF2 pathway.

Novel hub genes and regulatory network related to ferroptosis in tetralogy of Fallot

Ferroptosis is a newly discovered type of cell death mainly triggered by uncontrolled lipid peroxidation, and it could potentially have a significant impact on the development and progression of tetralogy of Fallot (TOF). Our project aims to identify and validate potential genes related to ferroptosis in TOF. We obtained sequencing data of TOF from the GEO database and ferroptosis-related genes from the ferroptosis database. We employed bioinformatics methods to analyze the differentially expressed mRNAs (DEmRNAs) and microRNAs between the normal control group and TOF group and identify DEmRNAs related to ferroptosis. Protein-protein interaction analysis was conducted to screen hub genes. Furthermore, a miRNA-mRNA-TF co-regulatory network was constructed to utilize prediction software. The expression of hub genes was further validated through quantitative real-time reverse-transcription polymerase chain reaction (qRT-PCR). After conducting the differential gene analysis, we observed that in TOF, 41 upregulated mRNAs and three downregulated mRNAs associated with ferroptosis genes were found. Further Gene Ontology/Kyoto Encyclopedia of Genes and Genomes analysis revealed that these genes were primarily involved in molecular functions and biological processes related to chemical stress, oxidative stress, cellular response to starvation, response to nutrient levels, cellular response to external stimulus, and cellular response to extracellular stimulus. Furthermore, we constructed a miRNA-mRNA-TF co-regulatory network. qRT-PCR analysis of the right ventricular tissues from human cases showed an upregulation in the mRNA levels of KEAP1 and SQSTM1. Our bioinformatics analysis successfully identified 44 potential genes that are associated with ferroptosis in TOF. This finding significantly contributes to our understanding of the molecular mechanisms underlying the development of TOF. Moreover, these findings have the potential to open new avenues for the development of innovative therapeutic approaches for the treatment of this condition.

The nuclear factor erythroid 2-related factor 2/p53 axis in breast cancer

One of the most important factors involved in the response to oxidative stress (OS) is the nuclear factor erythroid 2-related factor 2 (Nrf2), which regulates the expression of components such as antioxidative stress proteins and enzymes. Under normal conditions, Kelch-like ECH-associated protein 1 (Keap1) keeps Nrf2 in the cytoplasm, thus preventing its translocation to the nucleus and inhibiting its role. It has been established that Nrf2 has a dual function; on the one hand, it promotes angiogenesis and cancer cell metastasis while causing resistance to drugs and chemotherapy. On the other hand, Nrf2 increases expression and proliferation of glutathione to protect cells against OS. p53 is a tumour suppressor that activates the apoptosis pathway in aging and cancer cells in addition to stimulating the glutaminolysis and antioxidant pathways. Cancer cells use the antioxidant ability of p53 against OS. Therefore, in the present study, we discussed function of Nrf2 and p53 in breast cancer (BC) cells to elucidate their role in protection or destruction of cancer cells as well as their drug resistance or antioxidant properties.

Iron-Dependent Cell Death: A New Treatment Approach against Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a devastating tumor type where a very high proportion of people diagnosed end up dying from cancer. Surgical resection is an option for only about 20% of patients, where the 5-year survival increase ranges from 10 to 25%. In addition to surgical resection, there are adjuvant chemotherapy schemes, such as FOLFIRINOX (a mix of Irinotecan, oxaliplatin, 5-Fluorouraci and leucovorin) or gemcitabine-based treatment. These last two drugs have been compared in the NAPOLI-3 clinical trial, and the NALIRIFOX arm was found to have a higher overall survival (OS) (11.1 months vs. 9.2 months). Despite these exciting improvements, PDAC still has no effective treatment. An interesting approach would be to drive ferroptosis in PDAC cells. A non-apoptotic reactive oxygen species (ROS)-dependent cell death, ferroptosis was first described by Dixon et al. in 2012. ROS are constantly produced in the tumor cell due to high cell metabolism, which is even higher when exposed to chemotherapy. Tumor cells have detoxifying mechanisms, such as Mn-SOD or the GSH-GPX system. However, when a threshold of ROS is exceeded in the tumor cell, the cell's antioxidant systems are overwhelmed, resulting in lipid peroxidation and, ultimately, ferroptosis. In this review, we point out ferroptosis as an approach to consider in PDAC and propose that altering the cellular ROS balance by combining oxidizing agents or with inhibitors of the main cellular detoxifiers triggers ferroptosis in PDAC.

Bioactivity-guided fractionation of Helicteres angustifolia L. extract and its molecular evidence for tumor suppression

Helicteres angustifolia L. (Helicteres angustifolia) has been commonly used in folk medicine to treat cancer; however, its mechanisms of action remain obscure. In our earlier work, we reported that aqueous extract of H. angustifolia root (AQHAR) possesses attractive anticancer properties. In the present study, we isolated five ethanol fractions from AQHAR and investigated their therapeutic efficacy in human non-small cell lung cancer (NSCLC) cells. The results showed that among the five fractions, the 40% ethanol fraction (EF40) containing multiple bioactive compounds exhibited the best selective killing effect on NSCLC cells with no obvious toxicity to normal human fibroblasts. Mechanistically, EF40 reduced the expression of nuclear factor-E2-related factor 2 (Nrf2), which is constitutively expressed at high levels in many types of cancers. As a result, Nrf2-dependent cellular defense responses are suppressed, leading to the intracellular accumulation of reactive oxygen species (ROS). Extensive biochemical analyses revealed that EF40 caused cell cycle arrest and apoptosis through activation of the ROS-mediated DNA damage response. Furthermore, treatment with EF40 compromised NSCLC cell migration, as evidenced by the downregulation of matrix metalloproteinases (MMPs) and heterogeneous nuclear ribonucleoprotein K (hnRNP-K). In vivo studies using A549 xenografts in nude mice also revealed significant suppression of tumor growth and lung metastasis in the treated group. We propose that EF40 may serve as a potential natural anti-NSCLC drug that warrants further mechanistic and clinical attention.

Anticancer properties of sulforaphane: current insights at the molecular level

Sulforaphane (SFN) is an isothiocyanate with multiple biomedical applications. Sulforaphane can be extracted from the plants of the genus Brassica. However, broccoli sprouts are the chief source of sulforaphane and are 20 to 50 times richer than mature broccoli as they contain 1,153 mg/100 g. SFN is a secondary metabolite that is produced as a result of the hydrolysis of glucoraphanin (a glucosinolate) by the enzyme myrosinase. This review paper aims to summarize and understand the mechanisms behind the anticancer potential of sulforaphane. The data was collected by searching PubMed/MedLine, Scopus, Web of Science, and Google Scholar. This paper concludes that sulforaphane provides cancer protection through the alteration of various epigenetic and non-epigenetic pathways. It is a potent anticancer phytochemical that is safe to consume with minimal side effects. However, there is still a need for further research regarding SFN and the development of a standard dose.

Blastocystis sp. reduces the efficacy of 5-fluorouracil as a colorectal cancer chemotherapeutic treatment

Blastocystis is an enteric protozoan parasite with extensive genetic variation and unclear pathogenicity. It is commonly associated with gastrointestinal symptoms such as nausea, diarrhea, vomiting and abdominal pain in immunocompromised individuals. In this study, we explored the in vitro and in vivo effects of Blastocystis on the activity of a commonly used CRC chemotherapeutic agent, 5-FU. The cellular and molecular effects of solubilized antigen of Blastocystis in the presence of 5-FU were investigated using HCT116, human CRC cell line and CCD 18-Co, normal human colon fibroblast cells. For the in vivo study, 30 male Wistar rats were divided into six groups, as follows; Control Group: oral administration of 0.3ml Jones' medium, Group A: rats injected with azoxymethane (AOM), Group A-30FU: Rats injected with AOM and administered 30mg/kg 5-FU, Group B-A-30FU: rats inoculated with Blastocystis cysts, injected with AOM and administered 30mg/kg 5-FU, Group A-60FU: rats injected with AOM and administered 60mg/kg 5-FU and Group B-A-60FU: rats inoculated with Blastocystis cysts, injected with AOM and administered 60mg/kg 5-FU. The in vitro study revealed that the inhibitory potency of 5-FU at 8μM and 10μM was reduced from 57.7% to 31.6% (p < 0.001) and 69.0%-36.7% (p < 0.001) respectively when co-incubated with Blastocystis antigen for 24 h. However, the inhibitory potency of 5-FU in CCD-18Co cells was not significantly affected in the presence of Blastocystis antigen. The reduced inhibitory potency of 5-FU against cancer cell proliferation due to the presence of Blastocystis is consistent with the upregulation of expression of type 2 cytokines, transforming growth factor (TGF-β) and nuclear factor E2-related factor 2 (Nrf2) gene expression. Increased inflammation and abnormal histopathological findings along with a significant cancer multiplicity and adenoma incidence were evident in the intestine of the B-A-30FU and B-A-60FU groups when compared with the A-30FU and A-60FU groups respectively. Our in vitro and in vivo findings indicate that Blastocystis infection could potentially interfere with chemotherapy regimens such as 5-FU in CRC patients undergoing chemotherapy.

A comprehensive review of stroke-related signaling pathways and treatment in western medicine and traditional Chinese medicine

This review provides insight into the complex network of signaling pathways and mechanisms involved in stroke pathophysiology. It summarizes the historical progress of stroke-related signaling pathways, identifying potential interactions between them and emphasizing that stroke is a complex network disease. Of particular interest are the Hippo signaling pathway and ferroptosis signaling pathway, which remain understudied areas of research, and are therefore a focus of the review. The involvement of multiple signaling pathways, including Sonic Hedgehog (SHH), nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE), hypoxia-inducible factor-1α (HIF-1α), PI3K/AKT, JAK/STAT, and AMPK in pathophysiological mechanisms such as oxidative stress and apoptosis, highlights the complexity of stroke. The review also delves into the details of traditional Chinese medicine (TCM) therapies such as Rehmanniae and Astragalus, providing an analysis of the recent status of western medicine in the treatment of stroke and the advantages and disadvantages of TCM and western medicine in stroke treatment. The review proposes that since stroke is a network disease, TCM has the potential and advantages of a multi-target and multi-pathway mechanism of action in the treatment of stroke. Therefore, it is suggested that future research should explore more treasures of TCM and develop new therapies from the perspective of stroke as a network disease.

Nrf2-Mediated Antioxidant Defense and Thyroid Hormone Signaling: A Focus on Cardioprotective Effects

Thyroid hormones (TH) perform a plethora of actions in numerous tissues and induce an overall increase in metabolism, with an augmentation in energy demand and oxygen expenditure. Oxidants are required for normal thyroid-cell proliferation, as well as for the synthesis of the main hormones secreted by the thyroid gland, triiodothyronine (T3) and thyroxine (T4). However, an uncontrolled excess of oxidants can cause oxidative stress, a major trigger in the pathogenesis of a broad spectrum of diseases, including inflammation and cancer. In particular, oxidative stress is implicated in both hypo- and hyper-thyroid diseases. Furthermore, it is important for the TH system to rely on efficient antioxidant defense, to maintain balance, despite sustained tissue exposure to oxidants. One of the main endogenous antioxidant responses is the pathway centered on the nuclear factor erythroid 2-related factor (Nrf2). The aim of the present review is to explore the multiple links between Nrf2-related pathways and various TH-associated conditions. The main aspect of TH signaling is described and the role of Nrf2 in oxidant-antioxidant homeostasis in the TH system is evaluated. Next, the antioxidant function of Nrf2 associated with oxidative stress induced by TH pathological excess is discussed and, subsequently, particular attention is given to the cardioprotective role of TH, which also acts through the mediation of Nrf2. In conclusion, the interaction between Nrf2 and most common natural antioxidant agents in altered states of TH is briefly evaluated.

Junction of the redox dynamic, orchestra of signaling, and altered metabolism in regulation of T- cell lymphoma

T-cell lymphoma is a hematologic neoplasm derived from the lymphoid lineage. It belongs to a diverse group of malignant disorders, mostly affecting the young population worldwide, that vary with respect to molecular features as well as genetic and clinical complexities. Cancer cells rewire the cellular metabolism, persuading it to meet new demands of growth and proliferation. Furthermore, the metabolic alterations and heterogeneity are aberrantly driven in cancer by a combination of genetic and non-genetic factors, including the tumor microenvironment. New insight into cancer metabolism highlights the importance of nutrient supply to tumor development and therapeutic responses. Importantly, oxidative stress due to an imbalance in the redox status of reactive species via exogenous and/or endogenous factors is closely related to multiple aspects of cancer. This alters the signaling pathways governed through the multiple intracellular signal transduction and transcription factors, leading to tumor progression. These oncogenic signaling molecules are regulated through different redox sensors, including nuclear factor-erythroid 2 related factor 2 (Nrf2), phase-II antioxidant enzyme, and NQO1 (NADPH quinone oxidoreductase (1). The existing understanding of the molecular mechanisms of T-cell lymphoma regulation through the cross-talk of redox sensors under the influence of metabolic vulnerability is not well explored. This review highlights the role of the redox dynamics, orchestra of signaling, and genetic regulation involved in T-cell lymphoma progression in addition to the challenges to their etiology, treatment, and clinical response in light of recent updates.

Acetaminophen-induced liver injury: Molecular mechanism and treatments from natural products

Acetaminophen (APAP) is a widely used analgesic and antipyretic over-the-counter medicine worldwide. Hepatotoxicity caused by APAP overdose is one of the leading causes of acute liver failure (ALF) in the US and in some parts of Europe, limiting its clinical application. Excessive APAP metabolism depletes glutathione and increases N-acetyl-p-benzoquinoneimide (NAPQI) levels, leading to oxidative stress, DNA damage, and cell necrosis in the liver, which in turn leads to liver damage. Studies have shown that natural products such as polyphenols, terpenes, anthraquinones, and sulforaphane can activate the hepatocyte antioxidant defense system with Nrf2 as the core player, reduce oxidative stress damage, and protect the liver. As the key enzyme metabolizing APAP into NAPQI, cytochrome P450 enzymes are also considered to be intriguing target for the treatment of APAP-induced liver injury. Here, we systematically review the hepatoprotective activity and molecular mechanisms of the natural products that are found to counteract the hepatotoxicity caused by APAP, providing reference information for future preclinical and clinical trials of such natural products.

Advances in understanding mechanisms underlying mitochondrial structure and function damage by ozone

Mitochondria are double-membraned organelles found in eukaryotic cells. The integrity of mitochondrial structure and function determines cell destiny. Mitochondria are also the "energy factories of cells." The production of energy is accompanied by reactive oxygen species (ROS) generation. Generally, the production and consumption of ROS maintains a balance in cells. Ozone is a highly oxidizing, harmful substance in ground-level atmosphere. Ozone inhalation causes oxidative injury owing to the generation of ROS, resulting in mitochondrial oxidative stress overload. Oxidative damage to the mitochondria induces a vicious cycle of ROS production which might destroy mitochondrial DNA and mitochondrial structure and function in cells. ROS can alter the phosphorylation of various signaling molecules, triggering a series of downstream signaling pathway reactions. These include inflammatory responses, pyroptosis, autophagy, and apoptosis. Changes involving these molecular mechanisms may be related to the occurrence of disease. According to numerous epidemiological investigations, ozone exposure induces respiratory, cardiovascular, and nervous system diseases in humans. In addition, these systems require large quantities of energy. Hence, the mitochondrial damage caused by ozone may act as a bridge between human diseases. However, the specific molecular mechanisms involved require further investigation. This review discusses our understanding of the structure and function of mitochondria the mechanisms underlying ozone-induced mitochondrial damage.

Targeting the NRF2/KEAP1 pathway in cervical and endometrial cancers

Cervical and endometrial cancers are among the most dangerous gynaecological malignancies, with high fatality and recurrence rates due to frequent diagnosis at an advanced stage and chemoresistance onset. The NRF2/KEAP1 signalling pathway plays an important role in protecting cells against oxidative damage due to increased reactive oxygen species (ROS) levels. NRF2, activated by ROS, induces the expression of antioxidant enzymes such as heme oxygenase, catalase, glutathione peroxidase and superoxide dismutase which neutralize ROS, protecting cells against oxidative stress damage. However, activation of NRF2/KEAP1 signalling in cancer cells results in chemoresistance, inactivating drug-mediated oxidative stress and protecting cancer cells from drug-induced cell death. We review the literature on the role of the NRF2/KEAP1 pathway in cervical and endometrial cancers, with a focus on the expression of its components and downstream genes. We also examine the role of the NRF2/KEAP1 pathway in chemotherapy resistance and how this pathway can be modulated by natural and synthetic modulators.

The critical role of the phytosterols in modulating tumor microenvironment via multiple signaling: A comprehensive molecular approach

Cancer is the leading cause of mortality and morbidity worldwide, and its cases are rapidly increasing every year. Several factors contribute to the development of tumorigenesis. including radiation, dietary lifestyle, smoking, environmental, and genetic factors. The cell cycle is regulated by a variety of molecular signaling proteins. However, when the proteins involved in the cell cycle regulation are altered, cellular growth and proliferation are significantly affected. Natural products provide an important source of new drug development for a variety of ailments. including cancer. Phytosterols (PSs) are an important class of natural compounds reported for numerous pharmacological activities, including cancer. Various PSs, such as ergosterol, stigmasterol, sitosterol, withaferin A, etc., have been reported for their anti-cancer activities against a variety of cancer by modulating the tumor microenvironment via molecular signaling pathways discussed within the article. These signaling pathways are associated with the production of pro-inflammatory mediators, growth factors, chemokines, and pro-apoptotic and anti-apoptotic genes. These mediators and their upstream signaling are very active within the variety of tumors and by modulating these signalings, thus PS exhibits promising anti-cancer activities. However, further high-quality studies are needed to firmly establish the clinical efficacy as well the safety of the phytosterols.

Dual role of Nrf2 in cancer: molecular mechanisms, cellular functions and therapeutic interventions

BACKGROUND

Nrf2 regulates oxidative stress, which is essential for cellular function. Fundamental initiation of Nrf2 in many malignancies increases prosurvival genes & endorses tumour cell propagation via metabolic reprogramming, suppression of tumour programmed cell death, & increased cancer stem cell self-renewal potential. More specifically, Nrf2 has been associated with cancer cell chemoresistance, radioresistance & inflammation-induced carcinogenesis.  METHODS AND RESULTS: Many Nrf2 inhibitors have been revealed for tumour treatment and targeting Nrf2 could be an effective cancer therapeutic method. Before spreading, cancer cells adapt to their surroundings. Cancer cells usually have mutations in tumor suppressor genes. In a variety of malignancies, somatic mutations & other anomalies in the Nrf2 genes, as well as renowned cancer suppressor genes including TP53, CDKN2A, PTEN & PIK3CA, have been found. In tumour cells, somatic mutations in the Nrf2 genes, as well as additional mechanisms that affect Nrf2 binding, and produce aberrant Nrf2 activation. Uncontrolled Nrf2 causes tumour cells to become resistant to antineoplastic drugs & reactive oxygen species (ROS), as well as guiding them toward metabolic reprogramming.  CONCLUSIONS: As a result, Nrf2 has been studied as potential malignancy treatment target. We covered the pathways, mechanisms, and dual characteristics of Nrf2 in malignancy in this article. We also discussed how Nrf2 inhibitors are targeted against cancer in this review.

Nuclear factor erythroid-2-related factor 2 (Nrf2) is a potential prognostic factor in patients with gastric adenocarcinoma

BACKGROUND

Gastric cancer is one of the leading causes of cancer-related death, and many researchers are focused on the discovery and use of different biomarkers in prognosis prediction. The use of Nrf2 as a prognostic marker in patients with gastric cancer remains controversial. In this study, we evaluated the expression of Nrf2 protein in gastric adenocarcinoma.

PATIENTS AND METHODS

A total of 86 patients who underwent gastric resection and D2 lymph node dissection due to gastric adenocarcinoma were included. Clinicopathological characteristics, such as age, gender, gastrectomy type, pathologic T (pT) and N (pN) stages, tumor grade, tumor type per Lauren's classification, presence of lymphovascular invasion, and Nrf2 expression were evaluated.

RESULTS

While pT, pN, and Nrf-2 expression were found to be negative prognostic predictors for overall survival in one-way analysis of variance, Nrf-2 expression was the only significant negative prognostic predictor in multivariance analysis. pT, pN, diffuse type, high tumor grade, and Nrf-2 expression significantly affected overall survival in Kaplan-Meier survival analyses (p = 0.02, p = 0.03, p < 0.01, p = 0.027, and p = 0.001, respectively).

CONCLUSIONS

Our findings support that Nrf2 is a prognostic marker in patients with gastric adenocarcinoma. Anti-Nrf2 therapy options should be investigated to improve prognosis in gastric cancer patients.

ARD1 stabilizes NRF2 through direct interaction and promotes colon cancer progression

AIMS

Aberrant overactivation/overexpression of NRF2 is implicated as a driving event in tumor progression, which has been attributed to its mutation or inactivation of the inhibitory protein, KEAP1. However, alternative mechanisms responsible for sustained activation of NRF2 are less understood.

MAIN METHODS

Human colon cancer cell lines and tissues obtained from colorectal cancer (CRC) patients were used. To examine the expression levels of ARD1 and NRF2, Western blot and immunofluorescence analyses were performed. To investigate the potential relevance of NRF2 and ARD1 to human CRC, NRF2 and ARD1 were individually silenced in human colon cancer cells (HCT-116) by transfection with their specific small interfering RNA (siRNA). To determine the functional role of ARD1 in NRF2 regulation, in situ proximate ligation, co-immunoprecipitation, nano-LC-ESI MS/MS, and in vitro acetylation assays were performed.

KEY FINDINGS

ARD1 knockdown in human colon cancer cell lines significantly reduced the protein levels of NRF2 without affecting its mRNA expression; however, silencing of NRF2 did not alter ARD1 protein expression. In addition, these two proteins were co-localized and physically interacted with each other both in human colon cancer cells (HCT-116) and human colon tumor tissues. Mechanistically, ARD1 overexpression increased the acetylation levels of NRF2. Moreover, an in vitro acetylation assay and mass spectrometric analysis demonstrated that ARD1 could directly acetylate NRF2. Ectopic expression of mutant forms of ARD1 with defective acetyltransferase activity reduced the stability of NRF2.

SIGNIFICANCE

In conclusion, ARD1 may potentiate the oncogenic function of NRF2 in human colon cancer by stabilizing this transcription factor.

Modulation of redox homeostasis: A strategy to overcome cancer drug resistance

Cancer treatment is hampered by resistance to conventional therapeutic strategies, including chemotherapy, immunotherapy, and targeted therapy. Redox homeostasis manipulation is one of the most effective innovative treatment techniques for overcoming drug resistance. Reactive oxygen species (ROS), previously considered intracellular byproducts of aerobic metabolism, are now known to regulate multiple signaling pathways as second messengers. Cancer cells cope with elevated amounts of ROS during therapy by upregulating the antioxidant system, enabling tumor therapeutic resistance via a variety of mechanisms. In this review, we aim to shed light on redox modification and signaling pathways that may contribute to therapeutic resistance. We summarized the molecular mechanisms by which redox signaling-regulated drug resistance, including altered drug efflux, action targets and metabolism, enhanced DNA damage repair, maintained stemness, and reshaped tumor microenvironment. A comprehensive understanding of these interrelationships should improve treatment efficacy from a fundamental and clinical research point of view.

Role of STAT3 and NRF2 in Tumors: Potential Targets for Antitumor Therapy

Signal transducer and activator of transcription 3 (STAT3) and nuclear factor erythroid-derived 2-like 2 (NRF2, also known as NFE2L2), are two of the most complicated transcription regulators, which participate in a variety of physiological processes. Numerous studies have shown that they are overactivated in multiple types of tumors. Interestingly, STAT3 and NRF2 can also interact with each other to regulate tumor progression. Hence, these two important transcription factors are considered key targets for developing a new class of antitumor drugs. This review summarizes the pivotal roles of the two transcription regulators and their interactions in the tumor microenvironment to identify potential antitumor drug targets and, ultimately, improve patients' health and survival.

Interactions between arsenic exposure, high-fat diet and NRF2 shape the complex responses in the murine gut microbiome and hepatic metabolism

Inorganic arsenic (iAs) exposure has been associated to various detrimental effects such as development of metabolic syndrome and type 2 diabetes via oxidative stress and induced prolonged activation of the NRF2 transcription factor. Such effects can be aggravated by poor dietary habits. The role of gut microbiota in promoting metabolic changes in response to arsenic has yet to be precisely defined. To address the complexity of the interactions between diet, NFE2L2/NRF2, and gut microbiota, we studied the chronic effects of iAs exposure in wild-type (WT) and Nrf2-/- mice fed normal (ND) vs. high-fat diet (HFD), on the gut microbial community in the context of hepatic metabolism. We demonstrate that all treatments and interactions influenced bacteria and metabolic profiles, with dietary differences causing a strong overlap of responses between the datasets. By identifying five metabolites of known microbial origin and following their fate across treatments, we provide examples on how gut microbial products can participate in the development of iAs and HFD-induced metabolic disease. Overall, our results underline the importance of the microbial community in driving gut-liver-cross talk during iAs and HFD exposure.

Deregulated transcription factors in cancer cell metabolisms and reprogramming

Metabolic reprogramming is an important cancer hallmark that plays a key role in cancer malignancies and therapy resistance. Cancer cells reprogram the metabolic pathways to generate not only energy and building blocks but also produce numerous key signaling metabolites to impact signaling and epigenetic/transcriptional regulation for cancer cell proliferation and survival. A deeper understanding of the mechanisms by which metabolic reprogramming is regulated in cancer may provide potential new strategies for cancer targeting. Recent studies suggest that deregulated transcription factors have been observed in various human cancers and significantly impact metabolism and signaling in cancer. In this review, we highlight the key transcription factors that are involved in metabolic control, dissect the crosstalk between signaling and transcription factors in metabolic reprogramming, and offer therapeutic strategies targeting deregulated transcription factors for cancer treatment.

Nrf2/p‑Fyn/ABCB1 axis accompanied by p‑Fyn nuclear accumulation plays pivotal roles in vinorelbine resistance in non‑small cell lung cancer

Adjuvant cisplatin‑vinorelbine is a standard therapy for stage II/III lung cancer. However, a poor survival rate of patients with lung cancer is attributed to vinorelbine resistance arising from ATP‑binding cassette (ABC) sub‑family B member 1 (ABCB1) and phosphorylated Fyn (p‑Fyn) overexpression. However, the underlying mechanisms remain unclear. NF‑E2‑related factor 2 (Nrf2) regulates the ABC family and activates the nuclear transport of Fyn. The present study evaluated the roles of the Nrf2/p‑Fyn/ABCB1 axis in vinorelbine‑resistant (VR) cells and clinical samples. To establish VR cells, H1299 cells were exposed to vinorelbine, and the intracellular reactive oxygen species (ROS) level in the H1299 cells was determined using a DCFH‑DA assay. The total and subcellular expression of Nrf2, ABCB1 and p‑Fyn in VR cells was evaluated. Immunofluorescence was used to detect the subcellular localization of p‑Fyn in VR cells. A cell viability assay was used to examine whether the sensitivity of VR cells to vinorelbine is dependent on Nrf2 activity. Immunohistochemistry was performed on 104 tissue samples from patients with lung cancer who underwent surgery followed by cisplatin‑vinorelbine treatment. The results revealed that persistent exposure to vinorelbine induced intracellular ROS formation in H1299 cells. p‑Fyn was localized in the nucleus, and ABCB1 and Nrf2 were overexpressed in VR cells. ABCB1 expression was dependent on Nrf2 downstream activation. The decreased expression of Nrf2 restored the sensitivity of VR cells to vinorelbine. In the surgical samples, Nrf2 and ABCB1 were associated with disease‑free survival, and p‑Fyn was associated with overall survival (P<0.05). On the whole, the present study demonstrates that Nrf2 upregulates ABCB1 and, accompanied by the nuclear accumulation of p‑Fyn, induces vinorelbine resistance. These findings may facilitate the development of drug resistance prevention strategies or new drug targets against non‑small cell lung cancer.

Exploring the role of Nrf2 signaling in glioblastoma multiforme

Glioblastoma multiforme (GBM) is one of the most aggressive glial cell tumors in adults. Although current treatment options for GBM offer some therapeutic benefit, median survival remains poor and does not generally exceed 14 months. Several genes, such as isocitrate dehydrogenase (IDH) enzyme and O6-methylguanine-DNA methyltransferase (MGMT), have been implicated in pathogenesis of the disease. Treatment is often adapted based on the presence of IDH mutations and MGMT promoter methylation status. Recent GBM cell line studies have associated Nuclear Factor Erythroid 2-Related Factor 2 (Nrf2) expression with high-grade tumors. Increased Nrf2 expression is often found in tumors with IDH-1 mutations. Nrf2 is an important transcription factor with anti-apoptotic, antioxidative, anti-inflammatory, and proliferative properties due to its complex interactions with multiple regulatory pathways. In addition, evidence suggests that Nrf2 promotes  GBM cell survival in hypoxic environment,by up-regulating hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF). Downregulation of Nrf2 has been shown to improve GBM sensitivity to chemotherapy drugs such as Temozolomide. Thus, Nrf2 could be a key regulator of GBM pathways and potential therapeutic target.  Further research efforts exploring an interplay between Nrf2 and major molecular signaling mechanisms could offer novel GBM drug candidates with a potential to significantly improve patients prognosis.

Targeting NRF2 Sensitizes Esophageal Adenocarcinoma Cells to Cisplatin through Induction of Ferroptosis and Apoptosis

Esophageal adenocarcinoma (EAC), the predominant type of esophageal cancer in the United States, develops through Barrett's esophagus (BE)-dysplasia-carcinoma cascade. Gastroesophageal reflux disease, where acidic bile salts refluxate into the esophagus, is the main risk factor for the development of BE and its progression to EAC. The NFE2-related factor 2 (NRF2) is the master cellular antioxidant regulator. We detected high NRF2 protein levels in the EAC cell lines and primary tissues. Knockdown of NRF2 significantly enhanced acidic bile salt-induced oxidative stress, DNA damage, and inhibited EAC cell growth. Brusatol, an NRF2 inhibitor, significantly inhibited NRF2 transcriptional activity and downregulated the NRF2 target genes. We discovered that in addition to inducing apoptosis, Brusatol alone or in combination with cisplatin (CDDP) induced significant lipid peroxidation and ferroptosis, as evidenced by reduced xCT and GPX4 expression, two known ferroptosis markers. The combination of Brusatol and CDDP significantly inhibited EAC tumor xenograft growth in vivo and confirmed the in vitro data showing ferroptosis as an important mechanism in the tumors treated with Brusatol or Brusatol and CDDP combination. Our data support the role of NRF2 in protecting against stress-induced apoptosis and ferroptosis in EACs. Targeting NRF2 in combination with platinum therapy can be an effective strategy for eliminating cancer cells in EAC.

The molecular biology and therapeutic potential of Nrf2 in leukemia

NF-E2-related factor 2 (Nrf2) transcription factor has contradictory roles in cancer, which can act as a tumor suppressor or a proto-oncogene in different cell conditions (depending on the cell type and the conditions of the cell environment). Nrf2 pathway regulates several cellular processes, including signaling, energy metabolism, autophagy, inflammation, redox homeostasis, and antioxidant regulation. As a result, it plays a crucial role in cell survival. Conversely, Nrf2 protects cancerous cells from apoptosis and increases proliferation, angiogenesis, and metastasis. It promotes resistance to chemotherapy and radiotherapy in various solid tumors and hematological malignancies, so we want to elucidate the role of Nrf2 in cancer and the positive point of its targeting. Also, in the past few years, many studies have shown that Nrf2 protects cancer cells, especially leukemic cells, from the effects of chemotherapeutic drugs. The present paper summarizes these studies to scrutinize whether targeting Nrf2 combined with chemotherapy would be a therapeutic approach for leukemia treatment. Also, we discussed how Nrf2 and NF-κB work together to control the cellular redox pathway. The role of these two factors in inflammation (antagonistic) and leukemia (synergistic) is also summarized.

Design and synthesis of Nrf2-derived hydrocarbon stapled peptides for the disruption of protein-DNA-interactions

Misregulation and mutations of the transcription factor Nrf2 are involved in the development of a variety of human diseases. In this study, we employed the technology of stapled peptides to address a protein-DNA-complex and designed a set of Nrf2-based derivatives. Varying the length and position of the hydrocarbon staple, we chose the best peptide for further evaluation in both fixed and living cells. Peptide 4 revealed significant enrichment within the nucleus compared to its linear counterpart 5, indicating potent binding to DNA. Our studies suggest that these molecules offer an interesting strategy to target activated Nrf2 in cancer cells.

TP53, CDKN2A/P16, and NFE2L2/NRF2 regulate the incidence of pure- and combined-small cell lung cancer in mice

Studies have shown that Nrf2^E79Q/+ is one of the most common mutations found in human tumors. To elucidate how this genetic change contributes to lung cancer, we compared lung tumor development in a genetically-engineered mouse model (GEMM) with dual Trp53/p16 loss, the most common mutations found in human lung tumors, in the presence or absence of Nrf2^E79Q/+. Trp53/p16-deficient mice developed combined-small cell lung cancer (C-SCLC), a mixture of pure-SCLC (P-SCLC) and large cell neuroendocrine carcinoma. Mice possessing the LSL-Nrf2^E79Q mutation showed no difference in the incidence or latency of C-SCLC compared with Nrf2^+/+ mice. However, these tumors did not express NRF2 despite Cre-induced recombination of the LSL-Nrf2^E79Q allele. Trp53/p16-deficient mice also developed P-SCLC, where activation of the NRF2^E79Q mutation associated with a higher incidence of this tumor type. All C-SCLCs and P-SCLCs were positive for NE-markers, NKX1-2 (a lung cancer marker) and negative for P63 (a squamous cell marker), while only P-SCLC expressed NRF2 by immunohistochemistry. Analysis of a consensus NRF2 pathway signature in human NE⁺-lung tumors showed variable activation of NRF2 signaling. Our study characterizes the first GEMM that develops C-SCLC, a poorly-studied human cancer and implicates a role for NRF2 activation in SCLC development.

Cisplatin Chemotherapy and Cochlear Damage: Otoprotective and Chemosensitization Properties of Polyphenols

Significance: Cisplatin is an important component of treatment regimens for different cancers. Notwithstanding that therapeutic success often results from partial efficacy or stabilizing the disease, chemotherapy failure is driven by resistance to drug treatment and occurrence of side effects, such as progressive irreversible ototoxicity. Cisplatin's side effects, including ototoxicity, are often dose limiting. Recent Advances: Cisplatin ototoxicity results from several mechanisms, including redox imbalance caused by reactive oxygen species production and lipid peroxidation, activation of inflammation, and p53 and its downstream pathways that culminate in apoptosis. Considerable efforts in research have targeted development of molecular interventions that can be concurrently administered with cisplatin or other chemotherapies to reduce side effect toxicities while preserving or enhancing the antineoplastic effects. Evidence from studies has indicated some polyphenols, such as curcumin, can help to regulate redox signaling and inflammatory effects. Furthermore, polyphenols can exert opposing effects in different types of tissues, that is, normal cells undergoing stressful conditions versus cancer cells. Critical Issues: This review article summarizes evidence of curcumin antioxidant effect against cisplatin-induced ototoxicity that is converted to a pro-oxidant activity in cisplatin-treated cancer cells, thus providing an ideal chemosensitivity combined with otoprotection. Polyphenols can modulate the adaptive responses to stress in the cisplatin-exposed cochlea. These adaptive effects can result from the interaction/cross talk between the cell's defenses, inflammatory molecules, and the key signaling molecules of signal transducers and activators of transcription 3 (STAT-3), nuclear factor κ-B (NF-κB), p53, and nuclear factor erythroid 2-related factor 2 (Nrf-2). Future Directions: We provide molecular evidence for alternative strategies for chemotherapy with cisplatin addressing the otoprotection and chemosensitization properties of polyphenols. Antioxid. Redox Signal. 36, 1229-1245.

The Role of NRF2/KEAP1 Pathway in Glioblastoma: Pharmacological Implications

Glioblastoma multiforme (GBM) grade IV glioma is the most frequent and deadly intracranial cancer. This tumor is determined by unrestrained progression, uncontroled angiogenesis, high infiltration and weak response to treatment, which is chiefly because of abnormal signaling pathways in the tumor. A member related to the Cap 'n' collar family of keypart-leucine zipper transcription agents-the transcription factor NF-E2-related factor 2 (Nrf2)-regulates adaptive protection answers by organized upregulation of many genes that produce the cytoprotective factors. In reply to cellular pressures types such as stresses, Nrf2 escapes Kelch-like ECH-related protein 1 (Keap1)-facilitated suppression, moves from the cytoplasm towards the nucleus and performs upregulation of gene expression of antioxidant responsive element (ARE). Nrf2 function is related tocontrolling many types of diseases in the human specially GBM tumor.Thus, we will review the epigeneticalregulatory actions on the Nrf2/Keap1 signaling pathway and potential therapeutic options in GBM by aiming the stimulation of Nrf2.

Licochalcone E inhibits trxR1 expression, alters Nrf2/STAT6 signal, and induces antitumor effects in vitro against human SH-SY5Y and SK-N-BE(2) neuroblastoma cells

Neuroblastoma (NB) is the most common solid tumor of the sympathetic nervous system (SNS) arising in childhood less than 15 years age. Licochalcone (Lic) is known to show inhibitory effects in cancer growth, and there has evidence suggested that Lic A inhibits hypoxic induced NB SK-N-SH cell proliferation. However, it is unclear whether LicE exerts similar effects in NB and the associated molecular mechanism of Lic in neuroblastoma is still unclear. In the current study, we found that LicE at the concentration 2, 4 and 6 μM all induced a profound reduction in cell viability, colony formation and cell proliferation. Next, LicE treatment effectively promoted cell apoptosis, inhibited cell migration and invasion. LicE significantly suppressed trxR1 expression, activated Nrf2 expression and inhibited STAT6 expression in SH-SY5Y and SK-N-BE(2) NB cells. We further identified that trxR1, STAT6 overexpression or Nrf2 silence reversed the antitumor effects of LicE in human SH-SY5Y and SK-N-BE(2) NB cells. Finally, LicE treatment significantly inhibited tumor growth in nude mice carrying a SK-N-SH cell xenograft. These results provide new insights into the effects and highlighting a novel mechanism of LicE through regulating trxR1/Nrf2/STAT6 signal pathway in NB.

Role of Nrf2 Signaling Cascade in Breast Cancer: Strategies and Treatment

Breast cancer is the second leading cancer among all types of cancers. It accounts for 12% of the total cases of cancers. The complex and heterogeneous nature of breast cancer makes it difficult to treat in advanced stages. The expression of various enzymes and proteins is regulated by several molecular pathways. Oxidative stress plays a vital role in cellular events that are generally regulated by nuclear factor erythroid 2-related factor 2 (Nrf2). The exact mechanism of Nrf2 behind cytoprotective and antioxidative properties is still under investigation. In healthy cells, Nrf2 expression is lower, which maintains antioxidative stress; however, cancerous cells overexpress Nrf2, which is associated with various phenomena, such as the development of drug resistance, angiogenesis, development of cancer stem cells, and metastasis. Aberrant Nrf2 expression diminishes the toxicity and potency of therapeutic anticancer drugs and provides cytoprotection to cancerous cells. In this article, we have discussed the attributes associated with Nrf2 in the development of drug resistance, angiogenesis, cancer stem cell generation, and metastasis in the specific context of breast cancer. We also discussed the therapeutic strategies employed against breast cancer exploiting Nrf2 signaling cascades.

Moving beyond the Tip of the Iceberg: DJ-1 Implications in Cancer Metabolism

DJ-1, also called Parkinson’s protein 7 (PARK7), is ubiquitously expressed and plays multiple actions in different physiological and, especially, pathophysiological processes, as evidenced by its identification in neurodegenerative diseases and its high expression in different types of cancer. To date, the exact activity of DJ-1 in carcinogenesis has not been fully elucidated, however several recent studies disclosed its involvement in regulating fundamental pathways involved in cancer onset, development, and metastatization. At this purpose, we have dissected the role of DJ-1 in maintaining the transformed phenotype, survival, drug resistance, metastasis formation, and differentiation in cancer cells. Moreover, we have discussed the role of DJ-1 in controlling the redox status in cancer cells, along with the ability to attenuate reactive oxygen species (ROS)-dependent cell death, as well as to mediate ferropotosis. Finally, a mention to the development of therapeutic strategies targeting DJ-1 has been done. We have reported the most recent studies, aiming to shed light on the role played by DJ-1 in different cancer aspects and create the foundation for moving beyond the tip of the iceberg.

Nrf2 Modulates the Hybrid Epithelial/Mesenchymal Phenotype and Notch Signaling During Collective Cancer Migration

Hybrid epithelial/mesenchymal cells (E/M) are key players in aggressive cancer metastasis. It remains a challenge to understand how these cell states, which are mostly non-existent in healthy tissue, become stable phenotypes participating in collective cancer migration. The transcription factor Nrf2, which is associated with tumor progression and resistance to therapy, appears to be central to this process. Here, using a combination of immunocytochemistry, single cell biosensors, and computational modeling, we show that Nrf2 functions as a phenotypic stability factor for hybrid E/M cells by inhibiting a complete epithelial-mesenchymal transition (EMT) during collective cancer migration. We also demonstrate that Nrf2 and EMT signaling are spatially coordinated near the leading edge. In particular, computational analysis of an Nrf2-EMT-Notch network and experimental modulation of Nrf2 by pharmacological treatment or CRISPR/Cas9 gene editing reveal that Nrf2 stabilizes a hybrid E/M phenotype which is maximally observed in the interior region immediately behind the leading edge. We further demonstrate that the Nrf2-EMT-Notch network enhances Dll4 and Jagged1 expression at the leading edge, which correlates with the formation of leader cells and protruding tips. Altogether, our results provide direct evidence that Nrf2 acts as a phenotypic stability factor in restricting complete EMT and plays an important role in coordinating collective cancer migration.

Nrf2 signaling pathway in trace metal carcinogenesis: A cross-talk between oxidative stress and angiogenesis

A large number of people worldwide are affected by chronic metal exposure, which is known to be associated with different type of malignancies. The mechanisms of metal carcinogenicity are complex in nature, and excessive reactive oxygen species (ROS) generation induced by chronic metal exposure, among the other factors, has been proposed as one of the major mechanisms involved in that process. In tumor cells, ROS buildup may lead to cell death through intrinsic and extrinsic signaling pathways. Furthermore, ROS-mediated redox signaling has a crucial role in angiogenesis, which is recognized as an essential step in tumor progression. There are several redox-modulating pathways and among them, the nuclear factor erythroid2-related factor2 (Nrf2), as a sensor of oxidative or electrophilic stress, has introduced as a master regulator of cellular response against environmental stresses. Activation of Nrf2 signaling induces expression of wide variety of antioxidant and detoxification enzymes genes. Thus, this transcription factor has recently received much attention as a target for cancer chemoprevention. But meanwhile, constitutive Nrf2 activation in cancerous cells may promote cancer progression and resistance to chemotherapy. The current review describes the major underlying mechanisms involved in carcinogenesis of trace metals: copper, silver, and cadmium, with a special focus on the Nrf2 signaling pathway as a crossroad between oxidative stress and angiogenesis.

Ultrasound-Responsive Nrf2-Targeting siRNA-Loaded Nanobubbles for Enhancing the Treatment of Melanoma

The siRNA-mediated inhibition of nuclear factor E2-related factor 2 (Nrf2) can be an attractive approach to overcome chemoresistance in various malignant tumors, including melanoma. This work aims at designing a new type of chitosan-shelled nanobubble for the delivery of siRNA against Nrf2 in combination with an ultrasound. A new preparation method based on a water–oil–water (W/O/W) double-emulsion was purposely developed for siRNA encapsulation in aqueous droplets within a nanobubble core. Stable, very small NB formulations were obtained, with sizes of about 100 nm and a positive surface charge. siRNA was efficiently loaded in NBs, reaching an encapsulation efficiency of about 90%. siNrf2-NBs downregulated the target gene in M14 cells, sensitizing the resistant melanoma cells to the cisplatin treatment. The combination with US favored NB cell uptake and transfection efficiency. Based on the results, nanobubbles have shown to be a promising US responsive tool for siRNA delivery, able to overcome chemoresistance in melanoma cancer cells.

Oxidative Stress-Related Mechanisms in Melanoma and in the Acquired Resistance to Targeted Therapies

Melanoma is a highly aggressive cancer with the poorest prognosis, representing the deadliest form of skin cancer. Activating mutations in BRAF are the most frequent genetic alterations, present in approximately 50% of all melanoma cases. The use of specific inhibitors towards mutant BRAF variants and MEK, a downstream signaling target of BRAF in the MAPK pathway, has significantly improved progression-free and overall survival in advanced melanoma patients carrying BRAF mutations. Nevertheless, despite these improvements, resistance still develops within the first year of therapy in around 50% of patients, which is a significant problem in managing BRAF-mutated advanced melanoma. Understanding these mechanisms is one of the mainstreams of the research on BRAFi/MEKi acquired resistance. Both genetic and epigenetic mechanisms have been described. Moreover, in recent years, oxidative stress has emerged as another major force involved in all the phases of melanoma development, from initiation to progression until the onsets of the metastatic phenotype and chemoresistance, and has thus become a target for therapy. In the present review, we discuss the current knowledge on oxidative stress and its signaling in melanoma, as well as the oxidative stress-related mechanisms in the acquired resistance to targeted therapies.