Overexpression of NRF2 is correlated with prognoses of patients with malignancies: A meta-analysis

FGFR2-triggered autophagy and activation of Nrf-2 reduce breast cancer cell response to anti-ER drugs

BACKGROUND

Genetic abnormalities in the FGFR signalling occur in 40% of breast cancer (BCa) patients resistant to anti-ER therapy, which emphasizes the potential of FGFR-targeting strategies. Recent findings indicate that not only mutated FGFR is a driver of tumour progression but co-mutational landscapes and other markers should be also investigated. Autophagy has been recognized as one of the major mechanisms underlying the role of tumour microenvironment in promotion of cancer cell survival, and resistance to anti-ER drugs. The selective autophagy receptor p62/SQSTM1 promotes Nrf-2 activation by Keap1/Nrf-2 complex dissociation. Herein, we have analysed whether the negative effect of FGFR2 on BCa cell response to anti-ER treatment involves the autophagy process and/or p62/Keap1/Nrf-2 axis.

METHODS

The activity of autophagy in ER-positive MCF7 and T47D BCa cell lines was determined by analysis of expression level of autophagy markers (p62 and LC3B) and monitoring of autophagosomes' maturation. Western blot, qPCR and proximity ligation assay were used to determine the Keap1/Nrf-2 interaction and Nrf-2 activation. Analysis of 3D cell growth in Matrigel® was used to assess BCa cell response to applied treatments. In silico gene expression analysis was performed to determine FGFR2/Nrf-2 prognostic value.

RESULTS

We have found that FGFR2 signalling induced autophagy in AMPKα/ULK1-dependent manner. FGFR2 activity promoted dissociation of Keap1/Nrf-2 complex and activation of Nrf-2. Both, FGFR2-dependent autophagy and activation of Nrf-2 were found to counteract the effect of anti-ER drugs on BCa cell growth. Moreover, in silico analysis showed that high expression of NFE2L2 (gene encoding Nrf-2) combined with high FGFR2 expression was associated with poor relapse-free survival (RFS) of ER+ BCa patients.

CONCLUSIONS

This study revealed the unknown role of FGFR2 signalling in activation of autophagy and regulation of the p62/Keap1/Nrf-2 interdependence, which has a negative impact on the response of ER+ BCa cells to anti-ER therapies. The data from in silico analyses suggest that expression of Nrf-2 could act as a marker indicating potential benefits of implementation of anti-FGFR therapy in patients with ER+ BCa, in particular, when used in combination with anti-ER drugs.

The Involvement of Peroxiporins and Antioxidant Transcription Factors in Breast Cancer Therapy Resistance

Breast cancer is still the leading cause of death in women of all ages. The reason for this is therapy resistance, which leads to the progression of the disease and the formation of metastases. Multidrug resistance (MDR) is a multifactorial process that leads to therapy failure. MDR involves multiple processes and many signaling pathways that support each other, making it difficult to overcome once established. Here, we discuss cellular-oxidative-stress-modulating factors focusing on transcription factors NRF2, FOXO family, and peroxiporins, as well as their possible contribution to MDR. This is significant because oxidative stress is a consequence of radiotherapy, chemotherapy, and immunotherapy, and the activation of detoxification pathways could modulate the cellular response to therapy and could support MDR. These proteins are not directly responsible for MDR, but they support the survival of cancer cells under stress conditions.

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.

Stapled Peptides as Direct Inhibitors of Nrf2-sMAF Transcription Factors

Nuclear factor erythroid-related 2-factor 2 (Nrf2) is a transcription factor traditionally thought of as a cellular protector. However, in many cancers, Nrf2 is constitutively activated and correlated with therapeutic resistance. Nrf2 heterodimerizes with small musculoaponeurotic fibrosarcoma Maf (sMAF) transcription factors, allowing binding to the antioxidant responsive element (ARE) and induction of transcription of Nrf2 target genes. While transcription factors are historically challenging to target, stapled peptides have shown great promise for inhibiting these protein-protein interactions. Herein, we describe the first direct cell-permeable inhibitor of Nrf2/sMAF heterodimerization. N1S is a stapled peptide designed based on AlphaFold predictions of the interactions between Nrf2 and sMAF MafG. A cell-based reporter assay combined with in vitro biophysical assays demonstrates that N1S directly inhibits Nrf2/MafG heterodimerization. N1S treatment decreases the transcription of Nrf2-dependent genes and sensitizes Nrf2-dependent cancer cells to cisplatin. Overall, N1S is a promising lead for the sensitization of Nrf2-addicted cancers.

Role of Nrf2 in bisphenol effects: a review study

Bisphenols (BPs), the main endocrine-disrupting chemicals used in polycarbonate plastics, epoxy-phenol resins, and some other manufacturers, have been interestingly focused to find their toxic effects in recent years. Due to the strong relation between bisphenols and some crucial receptors such as ERs, AR, glucocorticoid receptor, THRs, ERRs, hPXR, AhR, and etcetera, the disrupting and oncogenic role of these chemicals on reproductive, respiratory, and circulatory systems and a broad group of body tissues have been investigated. BPs induce oxidant enzymes, exert antioxidant enzymes from body cells, and result in the expression of proinflammatory genes, leading to cell apoptosis and inflammation. To maintain the homeostasis of human body cells, Nrf2, the key regulator of oxidative stress (Ashrafizadeh et al., 2020a; Ashrafizadeh et al., 2020c; Boroumand et al., 2018), confronts BP-induced ROS and RNS through the activation of antioxidant enzymes such as SOD1/2, CAT, GSH, GPX, HO-1, and etcetera. Chemicals and drugs such as LUT, NAC, GEN, L-NMMA, Ph₂Se₂, and GE can regulate the interactions between BPs and Nrf2. Despite the vital role of controlled levels of Nrf2 as an anti-inflammatory and antiapoptotic element, the uncontrolled activity of this transcription factor could lead to cell proliferation and tumorigenesis through NQO1, SLC7a11, Gclm, HMOX1, NQO1 gene activation, and some other genes. To avoid the excessive activity of Nrf2, some protein complexes like CUL3-RBX1-Keap1 (as the primary regulator), β-TrCP, and WDR23 regulate Nrf2's function. It is necessary to note that BPA, as the most famous member, is further reviewed due to its resemblance to the bisphenol family to each other.

Cannabidiol Inhibits Tumorigenesis in Cisplatin-Resistant Non-Small Cell Lung Cancer via TRPV2

Simple Summary

Drug resistance is the key factor contributing to the therapeutic failure of lung cancer and the deaths related to lung cancer. Our study demonstrated that small molecular weight non-psychotropic phytochemical, cannabidiol (CBD), inhibits growth and metastasis of drug-resistant non-small cell lung cancer cells (NSCLC) cells in-vitro and in-vivo. We further discovered that CBD mediates its anti-cancer effects in part via an ion channel receptor, TRPV2, present on lung adenocarcinoma. Moreover, we showed that CBD induces apoptosis of cisplatin-resistant cells by modulating oxidative stress pathways. Overall, these studies indicate that CBD could be used as a promising therapeutic strategy in TRPV2 expressing cisplatin-resistant NSCLC.

Abstract

Chemotherapy forms the backbone of current treatments for many patients with advanced non-small-cell lung cancer (NSCLC). However, the survival rate is low in these patients due to the development of drug resistance, including cisplatin resistance. In this study, we developed a novel strategy to combat the growth of cisplatin-resistant (CR) NSCLC cells. We have shown that treatment with the plant-derived, non-psychotropic small molecular weight molecule, cannabidiol (CBD), significantly induced apoptosis of CR NSCLC cells. In addition, CBD treatment significantly reduced tumor progression and metastasis in a mouse xenograft model and suppressed cancer stem cell properties. Further mechanistic studies demonstrated the ability of CBD to inhibit the growth of CR cell lines by reducing NRF-2 and enhancing the generation of reactive oxygen species (ROS). Moreover, we show that CBD acts through Transient Receptor Potential Vanilloid-2 (TRPV2) to induce apoptosis, where TRPV2 is expressed on human lung adenocarcinoma tumors. High expression of TRPV2 correlates with better overall survival of lung cancer patients. Our findings identify CBD as a novel therapeutic agent targeting TRPV2 to inhibit the growth and metastasis of this aggressive cisplatin-resistant phenotype in NSCLC.

The Expression and Prognostic Value of Cancer Stem Cell Markers, NRF2, and Its Target Genes in TAE/TACE-Treated Hepatocellular Carcinoma

Background and Objectives: Activation of NRF2, a key transcription factor of cytoprotectant against oxidative stress, and its target genes are associated with aggressive tumor progression, metastasis and poor survival. In addition, NRF2 signaling mediates cancer stem cell (CSC)-like properties in hepatocellular carcinoma (HCC) cells. Moreover, CSCs have been associated with HCC onset and unfavorable prognosis. Transcatheter arterial embolization (TAE) and/or transcatheter arterial chemoembolization (TACE), which attempt to restrict blood supply to diminish tumor growth, can create a hypoxic environment. However, its effect on NRF2 signaling and CSC marker CD133 in the context of prognosis of HCCs have not been investigated. Therefore, we studied the possible role of the expressions of NRF2, its target genes and CSC markers CD133 and EpCAM on the survival of HCC patients after TAE/TACE. Materials and Methods: RT-qPCR was performed with 120 tumor (T) and adjacent tumor (N) tissue pairs. Expression of a single marker or combination was assessed for associations with survival of HCC patients after TAE/TACE. Results: The result of multivariate Cox regression showed that vascular invasion (HR, 1.821; p = 0.015), metastasis (HR, 2.033; p = 0.049) and CD133 overexpression (HR, 2.013; p = 0.006) were associated with poor survival. In a Kaplan–Meier survival analysis, patients with high expression of CD133 had shorter overall survival (OS) than those with low expression of CD133 in post-TAE/TACE HCC (p < 0.001). In contrast, neither NRF2 nor components of its signaling pathway correlated with survival. Combination marker analysis showed that co-expression of NQO1 and CD133 was associated with poor outcome. Conclusions: This study suggests that analyzing the expression status of CD133 alone and co-expression of NQO1 and CD133 may have additional value in predicting the outcome of TAE/TACE-treated HCC patients.

Nuclear Factor Erythroid 2-related Factor 2 Knockout Suppresses the Development of Aggressive Colorectal Cancer Formation Induced by Azoxymethane/Dextran Sulfate Sodium-Treatment in Female Mice

Colon tumors develop more frequently in male than in female. Nuclear factor erythroid 2-related factor 2 (Nrf2) plays differential roles in the stage of tumorigenesis. The purpose of this study was to investigate the role of Nrf2 on colitis-associated tumorigenesis using Nrf2 knockout (KO) female mice. Azoxymethane (AOM) and dextran sulfate sodium (DSS)-treated wild-type (WT) and Nrf2 KO female mice were sacrificed at week 2 and 16 after AOM injection. Severity of colitis, tumor incidence, and levels of inflammatory mediators were evaluated in AOM/DSS-treated WT and Nrf2 KO mice. Furthermore, qRT-PCR, Western blot abnalysis, and ELISA were performed in colon tissues. At week 2, AOM/DSS-induced colon tissue damages were significantly greater in Nrf2 KO than in WT mice. At week 16, tumor numbers (> 2 mm size) were significantly lower in both the proximal and distal colon in Nrf2 KO compared to WT. The overall incidences of adenoma/cancer of the proximal colon and submucosal invasive cancer of the distal colon were reduced by Nrf2 KO. The mRNA and protein expression levels of NF-κB-related mediators (i.e., iNOS and COX-2) and Nrf2-related antioxidants (i.e., heme oxygenase-1 and glutamate-cysteine ligase catalytic subunit) were significantly lower in the Nrf2 KO than in WT mice. Interestingly, the protein level of 15-hydroxyprostaglandin dehydrogenase (15-PGDH) was higher in AOM/DSS-treated Nrf2 KO than in WT mice. Our results support the oncogenic effect of Nrf2 in the later stage of carcinogenesis and upregulation of tumor suppressor 15-PGDH might contribute to the repression of colitis-associated tumorigenesis in Nrf2 KO female mice.

Identification of Redox-Sensitive Transcription Factors as Markers of Malignant Pleural Mesothelioma

Simple Summary

Malignant pleural mesothelioma is a lung tumor associated with asbestos exposure, with a poor prognosis, and a difficult pharmacological approach. Asbestos exposure is very toxic for the lungs, which counteract this toxic effect by activating some antioxidant defense proteins. When these proteins are more active that in normal conditions, as in several cancers, these tumors become able to survive and resist to stress or chemotherapy. In our laboratory, we collected cellular samples of mesothelioma and non-transformed mesothelium from Hospital’s Biobank and we evaluated these proteins. Our results demonstrated these proteins are upregulated in mesothelioma cells and not in non-transformed mesothelium. This event could be associated to toxic effects evoked by asbestos exposure, highlighting the need in the future to monitor asbestos-exposed people by measuring biomarkers identified, in the attempt to identify them as possible predictive markers and potential pharmacological targets addressed to improve mesothelioma prognosis.

Abstract

Although asbestos has been banned in most countries around the world, malignant pleural mesothelioma (MPM) is a current problem. MPM is an aggressive tumor with a poor prognosis, so it is crucial to identify new markers in the preventive field. Asbestos exposure induces oxidative stress and its carcinogenesis has been linked to a strong oxidative damage, event counteracted by antioxidant systems at the pulmonary level. The present study has been focused on some redox-sensitive transcription factors that regulate cellular antioxidant defense and are overexpressed in many tumors, such as Nrf2 (Nuclear factor erythroid 2-related factor 2), Ref-1 (Redox effector factor 1), and FOXM1 (Forkhead box protein M1). The research was performed in human mesothelial and MPM cells. Our results have clearly demonstrated an overexpression of Nrf2, Ref-1, and FOXM1 in mesothelioma towards mesothelium, and a consequent activation of downstream genes controlled by these factors, which in turn regulates antioxidant defense. This event is mediated by oxidative free radicals produced when mesothelial cells are exposed to asbestos fibers. We observed an increased expression of Nrf2, Ref-1, and FOXM1 towards untreated cells, confirming asbestos as the mediator of oxidative stress evoked at the mesothelium level. These factors can therefore be considered predictive biomarkers of MPM and potential pharmacological targets in the treatment of this aggressive cancer.

17β-Estradiol strongly inhibits azoxymethane/dextran sulfate sodium-induced colorectal cancer development in Nrf2 knockout male mice

Nuclear factor erythroid 2-related factor 2 (Nrf2) has dual effects on inflammation and cancer progression depending on the microenvironment. Estrogens have a protective effect on colorectal cancer (CRC) development. The aim of this study was to investigate CRC development in Nrf2 knockout (KO) mice. Azoxymethane (AOM) and dextran sulfate sodium (DSS)-treated wild-type (WT) and Nrf2 KO male mice were sacrificed at weeks 2 and 16 after AOM injection with/without 17β-estradiol (E2) treatment during week 1. Disease activity index and colon tissue damage at week 2 showed strong attenuation following E2 administration in WT mice but to a lesser extent in Nrf2 KO male mice. At week 16, E2 significantly diminished AOM/DSS-induced adenoma/cancer incidence at distal colon in the Nrf2 KO group, but not in the WT. Furthermore, mRNA or protein levels of NF-κB-related mediators (i.e., iNOS, TNF-α, and IL-1β) and Nrf2-related antioxidants (i.e., NQO1 and HO-1) were significantly lower in the Nrf2 KO group regardless of E2 treatment compared to the WT. The expression of estrogen receptor beta (ERβ) was higher in the Nrf2 KO group than in the WT. In conclusion, estrogen further inhibits CRC by upregulating ERβ-related alternate pathways in the absence of Nrf2.

The Clinicopathological and Prognostic Significance of Nrf2 and Keap1 Expression in Hepatocellular Carcinoma

Nuclear factor E2-related factor2 (Nrf2) activation is associated with both cytoprotective effects and malignant behavior of cancer cells. This study aimed to evaluate the clinicopathological implications of the expression of Nrf2, pNrf2, and its regulator Keap1 in human hepatocellular carcinomas (HCCs). Tissue microarrays consisting of 285 surgically resected HCCs were immunohistochemically stained with pNrf2, Nrf2, Keap1, stemness-related markers (keratin 19 (K19), epithelial cell adhesion molecule (EpCAM)), carbonic anhydrase IX (CAIX), epithelial–mesenchymal transition (EMT)-related markers (ezrin, uPAR, E-cadherin), and p53, and the results were correlated with the clinicopathological features. pNrf2 expression was significantly associated with increased proliferative activity, as well as EpCAM, ezrin, p53, and CAIX expression and E-cadherin loss (p < 0.05, all). Strong cytoplasmic Nrf2 expression was associated with CAIX and ezrin expression (p < 0.05, both). Keap1 was associated with increased proliferative activity, portal vein invasion, EMT-related markers, and p53 expression in CAIX-negative HCCs (p < 0.05, all). Both pNrf2 and cytoplasmic Nrf2 expression were associated with decreased overall survival (p < 0.05, both), and cytoplasmic Nrf2 expression was an independent predictor of decreased overall survival on multivariate analysis (hazard ratio 4.15, p < 0.001). Both pNrf2 and cytoplasmic Nrf2 expression were associated with poor survival and aggressive behavior of HCC. In addition, Keap1 expression was also associated with aggressive HCC behavior in CAIX-negative HCCs, suggesting that Keap1 expression should be interpreted in the context of hypoxia status.

The prognostic value of NRF2 in breast cancer patients: a systematic review with meta-analysis

PURPOSE

Nuclear factor E2-related factor 2 (NRF2) is a transcription factor that plays a major role in the regulation of intracellular antioxidant response. The effect of NRF2 overexpression in many malignancies is still unclear and recent meta-analysis correlated NRF2 overexpression with poor prognosis in a variety of human cancers. However, the effect of NRF2 overexpression in breast cancer is still unclear. Thus, the main goal of this work was to clarify the role of NRF2 expression in survival and relapse of breast cancer patients by performing a systematic review according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) statement, followed by a meta-analysis.

METHODS

The electronic search was conducted in PubMed, Scopus, SciELO, Web of Science and Embase between November of 2017 and September of 2018. To be included, studies should evaluate NRF2 expression in breast cancer tissue, through immunohistochemistry and/or mRNA and had to report one or more of the following outcomes: overall survival (OS), disease-free survival (DFS), mean survival and median survival.

RESULTS

For the meta-analysis, seven studies were included and NRF2 expression was correlated with OS and DFS. It was observed that compared to patients with low NRF2 expression, patients with NRF2 overexpression had poorer OS with a hazard ratio of 1.82 (95% CI 1.32-2.50; p value < 0.0001), and poorer DFS, with a hazard ratio of 1.79 (95% CI 1.07-3.01; p value = 0.03).

CONCLUSIONS

These results suggest that tumours that overexpress NRF2 have a worse clinical outcome. Thus, NRF2 expression could be a marker for the prognostic of breast cancer patients and, in the future, it would be pertinent to focus on improving treatment efficacy for patients with NRF2 overexpression.

Current Status and Challenges of NRF2 as a Potential Therapeutic Target for Diabetic Cardiomyopathy

Diabetic cardiomyopathy is one of the main causes of heart failure and death in patients with diabetes mellitus. Reactive oxygen species produced excessively in diabetes mellitus cause necrosis, apoptosis, ferroptosis, inflammation, and fibrosis of the myocardium as well as impair the cardiac structure and function. It is increasingly clear that oxidative stress is a principal cause of diabetic cardiomyopathy. The transcription factor nuclear factor-erythroid 2 p45-related factor 2 (NRF2) activates the transcription of more than 200 genes in the human genome. Most of the proteins translated from these genes possess anti-oxidant, anti-inflammatory, anti-apoptotic, anti-ferroptotic, and anti-fibrotic actions. There is a growing body of evidence indicating that NRF2 and its target genes are crucial in preventing high glucose-induced oxidative damage in diabetic cardiomyopathy. Recently, many natural and synthetic activators of NRF2 are shown to possess promising therapeutic effects on diabetic cardiomyopathy in animal models of diabetic cardiomyopathy. Targeting NRF2 signaling by pharmacological entities is a potential approach to ameliorating diabetic cardiomyopathy. However, the persistent high expression of NRF2 in cancer tissues also protects the growth of cancer cells. This "dark side" of NRF2 increases the challenges of using NRF2 activators to treat diabetic cardiomyopathy. In addition, some NRF2 activators were found to have off-target effects. In this review, we summarize the current status and challenges of NRF2 as a potential therapeutic target for diabetic cardiomyopathy.