Correlation Between Nuclear Factor E2-Related Factor 2 Expression and Gastric Cancer Progression

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.

Effects of oxidative stress regulation in inflammation-associated gastric cancer progression treated using traditional Chinese medicines: A review

Gastric cancer (GC) is a global public health concern that poses a serious threat to human health owing to its high morbidity and mortality rates. Due to the lack of specificity of symptoms, patients with GC tend to be diagnosed at an advanced stage with poor prognosis. Therefore, the development of new treatment methods is particularly urgent. Chronic atrophic gastritis (CAG), a precancerous GC lesion, plays a key role in its occurrence and development. Oxidative stress has been identified as an important factor driving the development and progression of the pathological processes of CAG and GC. Therefore, regulating oxidative stress pathways can not only intervene in CAG development but also prevent the occurrence and metastasis of GC and improve the prognosis of GC patients. In this study, PubMed, CNKI, and Web of Science were used to search for a large number of relevant studies. The review results suggested that the active ingredients of traditional Chinese medicine (TCM) and TCM prescriptions could target and improve inflammation, pathological status, metastasis, and invasion of tumor cells, providing a potential new supplement for the treatment of CAG and GC.

Immune checkpoints represent a promising breakthrough in targeted therapy and prognosis of myelodysplastic syndrome

Myelodysplastic syndrome (MDS) is a hematological malignancy of undetermined etiology, possibly linked to chromosomal structural alterations, genetic mutations, presentation and carcinogenicity of variant antigens on cell surface, and the generation of pro-inflammatory microenvironment in the bone marrow. Current drugs are unable to cure this disease, and therefore, decreasing the survival and proliferation of malignant cells to delay disease progression and extend the survival time of patients becomes the primary approach to management. In recent years, the immune system has received increasing attention for its potential role in the occurrence and development of MDS, leading to the emergence of immunoregulation as a viable treatment option. The current review provides a brief overview of pathogenesis of MDS and current treatment principles. In the meantime, the significance of immune proteins in treatment and prognosis of MDS is also discussed.

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.

The Orexin-A/OX1R System Induces Cell Death in Pancreatic Cancer Cells Resistant to Gemcitabine and Nab-Paclitaxel Treatment

Pancreatic ductal adenocarcinoma (PDAC) represents the fourth cause of cancer-associated death in the West. This type of cancer has a very poor prognosis notably due to the development of chemoresistance when treatments including gemcitabine and Abraxane (Nab-paclitaxel) were prescribed. The identification of new treatment circumventing this chemoresistance represents a key challenge. Previous studies demonstrated that the activation of orexin receptor type 1 (OX1R), which was ectopically expressed in PDAC, by its natural ligand named orexin-A (OxA), led to anti-tumoral effect resulting in the activation of mitochondrial pro-apoptotic mechanism. Here, we demonstrated that OxA inhibited the pancreatic cancer cell (AsPC-1) growth and inhibited the tumor volume in preclinical models as effectively as gemcitabine and Nab-paclitaxel. Moreover, the combination therapy including OxA plus gemcitabine or OxA plus Nab-paclitaxel was additive on the inhibition of cancer cell growth and tumor development. More importantly, the treatment by OxA of chemoresistant tumors to gemcitabine or Nab-paclitaxel obtained by successive xenografts in mice revealed that OxA was able to induce a strong inhibition of tumor development, whereas no OxA resistance was identified in tumors. The OX1R/OxA system might be an innovative and powerful alternative treatment of chemoresistant PDAC.

The antioxidative stress regulator Nrf2 potentiates radioresistance of oral squamous cell carcinoma accompanied with metabolic modulation

Nuclear factor erythroid 2-related factor 2 (Nrf2), which regulates the expression of critical antioxidant proteins, was recently demonstrated to play a key role in cancer progression. Resistance to radiotherapy is a major obstacle in treating oral squamous cell carcinoma (OSCC). However, little is known about the association between Nrf2 and radioresistance in OSCC. Two OSCC cell lines (SAS and HSC-2) and their clinically relevant radioresistant (CRR) clones (SAS-R, HSC-2-R) were used. The effects of Nrf2 downregulation on radiosensitivity and the involvement of glycolysis in Nrf2-mediated radioresistance were evaluated. Immunohistochemistry of phosphorylated Nrf2 (p-Nrf2) was performed in 110 patients with OSCC who underwent preoperative chemoradiotherapy and surgery. Nrf2 was stably upregulated in CRR cells in vitro and in a mouse xenograft model. Moreover, elevated Nrf2 expression was associated with radioresistance. The enhancement of Nrf2-dependent glycolysis and glutathione synthesis was involved in the development of radioresistance. Additionally, p-Nrf2 expression was closely related to the pathological response to chemoradiotherapy, and its expression was predictive of prognosis in patients with advanced OSCC. Our results suggest that Nrf2 plays an important role in the radioresistance of OSCC accompanied by metabolic reprogramming. Targeting Nrf2 antioxidant pathway may represent a promising treatment strategy for highly malignant OSCC.

Ferroptosis: At the Crossroad of Gemcitabine Resistance and Tumorigenesis in Pancreatic Cancer

The overall five-year survival rate of pancreatic cancer has hardly changed in the past few decades (less than 10%) because of resistance to all known therapies, including chemotherapeutic drugs. In the past few decades, gemcitabine has been at the forefront of treatment for pancreatic ductal adenocarcinoma, but more strategies to combat drug resistance need to be explored. One promising possibility is ferroptosis, a form of a nonapoptotic cell death that depends on intracellular iron and occurs through the accumulation of lipid reactive oxygen species, which are significant in drug resistance. In this article, we reviewed gemcitabine-resistance mechanisms; assessed the relationship among ferroptosis, tumorigenesis and gemcitabine resistance, and explored a new treatment method for pancreatic cancer.

MicroRNA-328-3p facilitates the progression of gastric cancer via KEAP1/NRF2 axis

Gastric cancer is a common lethal malignancy and causes great cancer-related mortality worldwide. MicroRNA (miR)-328-3p is implicated in the progression of various human cancers; however, its role and mechanism in the progression of gastric cancer remain unclear.Human gastric cancer cells were incubated with miR-328-3p mimic, inhibitor or the matched negative control. Cell viability, colony formation, migrative and invasive capacity, cell apoptosis and oxidative stress were measured. To clarify the involvement of nuclear factor-E2-related factor 2 (NRF2) and kelch-like ECH-associated protein 1 (KEAP1), small interfering RNA was used. miR-328-3p was upregulated in human gastric cancer cells and tissues, and its level positively correlated with the progression of gastric cancer. miR-328-3p promoted cell viability, colony formation, migration and invasion, thereby facilitating the progression of gastric cancer. miR-328-3p mimic reduced, while miR-328-3p inhibitor increased apoptosis and oxidative stress of human gastric cancer cells. Mechanistically, miR-328-3p upregulated NRF2 via targeting KEAP1to attenuate excessive free radical production and cell apoptosis. miR-328-3p functions as an oncogenic gene and inhibiting miR-328-3p may help to develop novel therapeutic strategies of human gastric cancer.

Inhibition of the NRF2/KEAP1 Axis: A Promising Therapeutic Strategy to Alter Redox Balance of Cancer Cells

Significance: The nuclear factor erythroid 2-related factor 2/Kelch-like ECH-associated protein 1 (NRF2/KEAP1) pathway is a crucial and highly conserved defensive system that is required to maintain or restore the intracellular homeostasis in response to oxidative, electrophilic, and other types of stress conditions. The tight control of NRF2 function is maintained by a complex network of biological interactions between positive and negative regulators that ultimately ensure context-specific activation, culminating in the NRF2-driven transcription of cytoprotective genes. Recent Advances: Recent studies indicate that deregulated NRF2 activation is a frequent event in malignant tumors, wherein it is associated with metabolic reprogramming, increased antioxidant capacity, chemoresistance, and poor clinical outcome. On the other hand, the growing interest in the modulation of the cancer cells' redox balance identified NRF2 as an ideal therapeutic target. Critical Issues: For this reason, many efforts have been made to identify potent and selective NRF2 inhibitors that might be used as single agents or adjuvants of anticancer drugs with redox disrupting properties. Despite the lack of specific NRF2 inhibitors still represents a major clinical hurdle, the researchers have exploited alternative strategies to disrupt NRF2 signaling at different levels of its biological activation. Future Directions: Given its dualistic role in tumor initiation and progression, the identification of the appropriate biological context of NRF2 activation and the specific clinicopathological features of patients cohorts wherein its inactivation is expected to have clinical benefits, will represent a major goal in the field of cancer research. In this review, we will briefly describe the structure and function of the NRF2/ KEAP1 system and some of the most promising NRF2 inhibitors, with a particular emphasis on natural compounds and drug repurposing. Antioxid. Redox Signal. 34, 1428-1483.

Clinico-pathological and prognostic implications of Srx, Nrf2, and PROX1 expression in gastric cancer and adjacent non-neoplastic mucosa - an immunohistochemical study

Introduction

Sulfiredoxin (Srx), which is an endogenous antioxidant substance which could, regulate the signaling pathways of reactive oxygen species. Nuclear factor erythroid 2-related factor 2 (Nrf2) is Cap-N-collar (CNC) transcription factors family member that have essential roles in regulation of antioxidant response. The transcription factor PROX1 is a transcription factor and a key regulatory protein in cancer development.

Aim of the study

To analyze levels of tissue expression of Srx, Nrf2, and PROX1 in gastric cancer and adjacent non-neoplastic gastric mucosa to clarify the relationship between their expression levels, clinical, pathological parameters and patients’ outcome. The results might lead to discovering novel targeted therapies to gastric cancers.

Material and methods

We included 70 paraffin-embedded samples: 50 specimens from gastric carcinomas and 20 specimens from adjacent non-neoplastic gastric mucosa. All samples are stained with Srx, Nrf2, and PROX1 using immunohistochemistry, correlated their expression with clinicopathological and prognostic parameters of patients.

Results

High levels of Srx and Nrf2 expression were positively associated with higher cancer grade (p = 0.006, 0.031 respectively), advanced stage (p < 0.001, 0.02 respectively), higher incidence of distant metastases (p = 0.029, 0.03 respectively) and dismal outcome (p < 0.001). High levels of PROX1 expression were associated with lower cancer grade (p = 0.005), absence of lymph nodes metastases (p = 0.023), early stage (p = 0.003), absence of relapse (p = 0.004), and favorable outcome (p < 0.001).

Conclusions

Srx and Nrf2 expression increase gastric cancer invasiveness, suggesting their utility as poor prognostic markers, but PROX1 serves as a favorable prognostic marker of gastric cancer patients.

Luteolin Attenuates Glycerol-Induced Acute Renal Failure and Cardiac Complications Through Modulation of Kim-1/NF-κB/Nrf2 Signaling Pathways

Acute renal failure (ARF) has been documented as a life-threatening disease with high morbidity and mortality. We investigated the protective effect of Luteolin against ARF. In this study, forty-male Wistar albino rats were randomly divided into four groups (n = 10). Group A received normal saline. Group B received glycerol (10 ml/kg BW, 50% v/v in sterile saline, i.m.). Groups C and D were pretreated with Luteolin 100 and 200 mg/kg for 7 days, and thereafter administered Glycerol (10 ml/kg BW, 50% v/v in sterile saline, i.m.). Administration of glycerol significantly increased systolic blood pressure, diastolic blood pressure and mean arterial pressure. Renal protein carbonyl and xanthine oxidase increased significantly while significant reduction in the activity of renal glutathione peroxidase, glutathione S-transferase and glutathione reductase was observed in the glycerol intoxicated rats. Furthermore, administration of glycerol led to significant increases in serum creatinine and blood urea nitrogen together with reduction in nitric oxide (NO) bioavailability. Immunohistochemistry revealed that glycerol intoxication enhanced expressions of kidney injury molecule 1, nuclear factor kappa beta and cardiac troponin (CTnI). However, Luteolin pretreatment normalized blood pressure, reduced markers of oxidative stress, renal damage, and improved NO bioavailability. Luteolin also downregulated the expressions of kidney injury molecule 1, nuclear factor kappa beta and cardiac troponin. Together, Luteolin might open a novel therapeutic window for the treatment of acute renal failure and cardiac complication.

Evaluation of the Epigenetic Demethylation of NRF2, a Master Transcription Factor for Antioxidant Enzymes, in Colorectal Cancer

Background

Epigenetic changes in CpG islands of the promoter regions of homeostasis-related genes, including nuclear factor erythroid 2-related factor 2 (NRF2), have been shown to hold a significant role in the development of colorectal cancer. Therefore, we aimed to examine the DNA demethylation pattern of the NRF2 promoter region in cancerous lesions from patients with colorectal cancer and the association of methylation status with clinicopathological features in the Iranian population.

Methods

In this cross-sectional study, 114 colorectal tissue samples were collected. These samples included: 34 tumour tissue samples, 60 precancerous polyps, and 20 normal tissue samples. The promoter methylation status of the NRF2 gene was examined using methylation-specific PCR. Additionally, the relationship between the methylation status and the clinicopathological features was investigated.

Results

The frequency of NRF2 demethylation in the tumour samples was significantly higher compared to the polyp tissues (p= 0.003) and normal tissue (p= 0.009), indicating that cancerous colorectal tissues exhibit increased demethylation of the NRF2 promoter. After examining the demethylation status of tissue samples, the clinicopathological features were compared to the demethylation results. No significant association was found between NRF2 promoter demethylation and the clinicopathological features of patient samples.

Conclusion

Our findings suggest that the epigenetic modifications leading to NRF2 demethylation found in colorectal tumour samples may contribute to cancer progression from precancerous polyps to cancerous lesions.

Modulation of Oxidative Stress by Ozone Therapy in the Prevention and Treatment of Chemotherapy-Induced Toxicity: Review and Prospects

(1) Background: Cancer is one of the leading causes of mortality worldwide. Radiotherapy and chemotherapy attempt to kill tumor cells by different mechanisms mediated by an intracellular increase of free radicals. However, free radicals can also increase in healthy cells and lead to oxidative stress, resulting in further damage to healthy tissues. Approaches to prevent or treat many of these side effects are limited. Ozone therapy can induce a controlled oxidative stress able to stimulate an adaptive antioxidant response in healthy tissue. This review describes the studies using ozone therapy to prevent and/or treat chemotherapy-induced toxicity, and how its effect is linked to a modification of free radicals and antioxidants. (2) Methods: This review encompasses a total of 13 peer-reviewed original articles (most of them with assessment of oxidative stress parameters) and some related works. It is mainly focused on four drugs: Cisplatin, Methotrexate, Doxorubicin, and Bleomycin. (3) Results: In experimental models and the few existing clinical studies, modulation of free radicals and antioxidants by ozone therapy was associated with decreased chemotherapy-induced toxicity. (4) Conclusions: The potential role of ozone therapy in the management of chemotherapy-induced toxicity merits further research. Randomized controlled trials are ongoing.

Dendrobium Officinale Polysaccharides Protect against MNNG-Induced PLGC in Rats via Activating the NRF2 and Antioxidant Enzymes HO-1 and NQO-1

Dendrobium officinale polysaccharides (DOP) are the main effective ingredient in Dendrobium officinale. Nuclear factor erythroid 2-related factor 2 (NRF2) signaling is regarded as an important way to mitigate the effects of reactive oxygen species (ROS) damage and inhibit gastric cancer progress. This study introduces a previously unknown effect of DOP on precancerous lesions of gastric cancer (PLGC). The mechanism discussed herein is based on the NRF2 signal pathway as well as its downstream antioxidant enzymes heme oxygenase-1 (HO-1) and NADPH quinone oxidoreductase-1 (NQO-1). DOP was prepared by the alcohol deposition method, and its molecular weight was determined using High-Performance Gel-Permeation Chromatography (HPGPC). Sixty male rats were randomly divided into five groups: normal control group (NC), PLGC model group (PLGC), model treated with low dose (2.4 g/kg) of DOP (L-DOP), model treated with middle dose (4.8 g/kg) of DOP (M-DOP), and model treated with high dose (9.6 g/kg) of DOP (H-DOP). DOP was orally administered to rats for 15 consecutive days prior to the start of a seven-month course of 1-methyl-3-nitro-1-nitrosoguanidine (MNNG) exposure. Histological evaluation was observed by hematoxylin and eosin (HE) and alcian blue/periodic acid-Schiff (AB-PAS) staining. Alanine aminotransferase (ALT), aspartate transaminase (AST), serum creatinine (Scr), serum uric acid (UA), blood urea nitrogen (BUN), and HE staining were detected for liver and kidney function. The level of 8-hydroxy-deoxyguanosine (8-OHdG) in serum was detected by kits. The NRF2 protein expression was detected by immunohistochemistry, and western blotting was utilized to compare differential protein expression levels among cytoplasmic and nuclear cell fractions. Expression levels of antioxidant enzymes heme oxygenase 1 (HO-1), Glutamate-Cysteine Ligase Catalytic Subunit (GCLC), Glutamate-Cysteine Ligase Modifier Subunit (GCLM), and NAD(P)H: quinone oxidoreductase-1 (NQO-1) were analyzed by reverse transcriptase polymerase chain reaction (RT-PCR); furthermore, the protein expression of NRF2, HO-1, and NQO-1 was detected by western blotting. The results showed that the average content of DOP is 83%, and its molecular weight is mainly contained within 3500 and 1000000. The H-DOP experimental group exhibited noticeable weight gain after seven months, reduced intestinal metaplasia, and made the atypical hyperplasia to be kept in moderate or mild degree. Data also showed DOP to be capable of decreasing levels of ALT, UA, and BUN, all of which had been elevated following the appearance of MNNG-induced PLGCs. DOP was also seen to reduce the expression of 8-OHdG and promote the expression of NRF2 in the gastric mucosa. Furthermore, RT-PCR and western blotting results showed that DOP upregulated the gene and protein expression of HO-1 and NQO-1. These findings show that DOP prevents MNNG-induced PLGC along with subsequent liver and kidney damage. The protective effects of DOP are associated with the reduction of 8-OHdG levels as well as the activation of the NRF2 pathway and its related antioxidant enzymes, HO-1 and NQO-1.

The Nrf2/HO-1 axis can be a prognostic factor in clear cell renal cell carcinoma

OBJECTIVE

To study the protein expression level of Nrf2/HO-1 in clear cell renal cell carcinoma (ccRCC) and adjacent normal tissue and to explore its relationship with clinicopathological characteristics and prognosis in ccRCC patients.

MATERIALS AND METHODS

In total, 152 ccRCC patients with available follow-up and clinical data were enrolled, and sample microarrays were prepared for immunohistochemistry studies. The human ccRCC cell lines 786-O, OS-RC-2, A498, and ACHN were cultured for immunofluorescence. The protein concentrations of five ccRCC patients' tumor and adjacent normal renal tissues were prepared for Western blotting. Chi-squared tests, Fisher's exact test, Kaplan-Meier analyses, log-rank tests, and Cox regression were performed for statistical analyses.

RESULTS

The immunoreactivity results showed that the Nrf2 and HO-1 proteins were found in consistent locations in vitro and were expressed both in ccRCC and adjacent normal tissues. The two proteins were localized in the cytoplasm and nucleus of RCC tumor cells and in adjacent normal tissue cells. The expression levels of Nrf2 and HO-1 were significantly higher in ccRCC tissues than in the adjacent normal tissues. The Nrf2 protein level was found to be significantly correlated with the tumor size. Additionally, higher protein expression levels of Nrf2 and HO-1 were also correlated with worse overall survival outcomes and could potentially be used to predict the prognosis of ccRCC patients.

CONCLUSION

Our study provides an important theoretical basis for evaluating the clinical prognosis of ccRCC patients, which implies that the Nrf2/HO-1 axis can be a prognostic factor in ccRCC.

Long Noncoding RNA (lncRNA) MIR22HG Suppresses Gastric Cancer Progression through Attenuating NOTCH2 Signaling

BACKGROUND Long noncoding RNAs (lncRNAs) are important regulators in human disease, including cancers. LncRNA MIR22HG has been shown to inhibit the progression of endometrial carcinoma, lung cancer, and hepatocellular carcinoma. Its role in gastric cancer is unclear. This study investigated MIR22HG effects on gastric cancer. MATERIAL AND METHODS Gastric cancer tissues (n=43) and adjacent normal tissues (n=21) were collected. Patients' 5-year overall survival rate was analyzed. Human normal gastric mucosal cell line (GES-1) and gastric cancer cell lines (MKN-45, AGS, SGC-7901) were cultured. AGS and MKN-45 cells were transfected by pcDNA3 empty vector, pcDNA3-MIR22HG overexpression vector, MIR22HG siRNA and its negative control, NOTCH2 siRNA and its negative control, respectively. Proliferation was explored by CCK-8 assay. Migration and invasion were explored by Transwell. qRT-PCR and western blot were used to investigate mRNA and proteins expression, respectively. RESULTS MIR22HG expression was decreased in gastric cancer tissues and cells (P<0.05). Low MIR22HG expression indicated lower 5-year overall survival rate (P<0.05). Upregulation of MIR22HG inhibited AGS and MKN-45 cell proliferation, migration and invasion (all P<0.05). Downregulation of MIR22HG elevated AGS and MKN-45 cell proliferation, migration, and invasion (all P<0.05). MIR22HG negatively regulated NOTCH2 signaling. Silencing MIR22HG elevated HEY1 and nucleus NOTCH2 expression. Silencing of NOTCH2 suppressed AGS and MKN-45 cells proliferation, migration and invasion (all P<0.05). CONCLUSIONS LncRNA MIR22HG suppressed gastric cancer progression through attenuating NOTCH2 signaling.

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

Background

Previous published research has demonstrated that NRF2 expression is a poor prognostic factor for many malignancies. However, because of the small sample enrolled in a single study, it is difficult to draw valuable conclusions. Therefore, we hypothesized that NRF2 overexpression in cancer tissues may be associated with the prognoses of patients with solid malignancies, and conducted a systemic review and meta‐analysis.

Methods

A comprehensive search of PubMed, Web of Science, Science Direct, Embase, and Ovid databases for relevant studies regarding the role of NRF2 expression in solid malignancies was conducted. Hazard ratios (HR) and 95% confidence intervals (CIs) were extracted from these studies to provide pooled estimates of the effect of NRF2 expression on patients’ overall and disease‐free survival.

Results

Nine studies met the criteria for analysis. Statistical analysis demonstrated that compared to patients with low NRF2 expression, patients with overexpression of NRF2 had poorer overall survival (HR 2.01, 95% CI 1.57–2.56; P < 0.001) and disease‐free survival (HR 3.25, 95% CI 1.29–8.15; P = 0.025).

Conclusion

Published evidence of the role of NRF2 expression in survival of cancer patients is limited. This analysis supports the view that NRF2 overexpression is a poor prognostic factor for solid malignancies, thus optimizing treatment for patients with NRF2 overexpression may improve their overall survival.

Role of nuclear factor (erythroid-derived 2)-like 2 in the age-resistant properties of the glaucoma trabecular meshwork

Glaucoma is a major cause of irreversible blindness. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) regulates the expression of numerous antioxidants within cells and is therefore a focus of current ophthalmic research. To determine the roles of Nrf2 in mediating the glaucoma trabecular meshwork (GTM), the present study evaluated the levels of Nrf2 expression in GTM and human trabecular meshwork (HTM) cells by reverse-transcription-quantitative polymerase chain reaction and western blot analysis. It was principally observed that Nrf2 expression was downregulated in GTM cells. In addition, to determine the influence of Nrf2 on the apoptosis and proliferation of GTM and HTM cells, transfection assays and western blotting were performed to evaluate the expression of apoptosis-related proteins. The results of the current study indicated that Nrf2 may promote viability and reduce apoptosis in GTM and HTM cells. Collectively, these data suggest that Nrf2 may be a novel therapeutic target to treat glaucoma.

The Transcription Factor Nrf2 Protects Angiogenic Capacity of Endothelial Colony-Forming Cells in High-Oxygen Radical Stress Conditions

Background

Endothelial colony forming cells (ECFCs) have shown a promise in tissue engineering of vascular constructs, where they act as endothelial progenitor cells. After implantation, ECFCs are likely to be subjected to elevated reactive oxygen species (ROS). The transcription factor Nrf2 regulates the expression of antioxidant enzymes in response to ROS.

Methods

Stable knockdown of Nrf2 and Keap1 was achieved by transduction with lentiviral shRNAs; activation of Nrf2 was induced by incubation with sulforaphane (SFN). Expression of Nrf2 target genes was assessed by qPCR, oxidative stress was assessed using CM-DCFDA, and angiogenesis was quantified by scratch-wound and tubule-formation assays Results. Nrf2 knockdown led to a reduction of antioxidant gene expression and increased ROS. Angiogenesis was disturbed after Nrf2 knockdown even in the absence of ROS. Conversely, angiogenesis was preserved in high ROS conditions after knockdown of Keap1. Preincubation of ECFCs with SFN reduced intracellular ROS in the presence of H₂O₂ and preserved scratch-wound closure and tubule-formation.

Results

Nrf2 knockdown led to a reduction of antioxidant gene expression and increased ROS. Angiogenesis was disturbed after Nrf2 knockdown even in the absence of ROS. Conversely, angiogenesis was preserved in high ROS conditions after knockdown of Keap1. Preincubation of ECFCs with SFN reduced intracellular ROS in the presence of H₂O₂ and preserved scratch-wound closure and tubule-formation.

Conclusion

The results of this study indicate that Nrf2 plays an important role in the angiogenic capacity of ECFCs, particularly under conditions of increased oxidative stress. Pretreatment of ECFCs with SFN prior to implantation may be a protective strategy for tissue-engineered constructs or cell therapies.