Clinicopathological significance of nuclear factor (erythroid-2)-related factor 2 (Nrf2) expression in gastric cancer

Factors determining the sensitivity to proteasome inhibitors of multiple myeloma cells

Multiple myeloma is an incurable cancer that originates from antibody-producing plasma cells. It is characterized by an intrinsic ability to produce large amounts of immunoglobulin-like proteins. The high rate of synthesis makes myeloma cells dependent on protein processing mechanisms related to the proteasome. This dependence made proteasome inhibitors such as bortezomib and carfilzomib one of the most important classes of drugs used in multiple myeloma treatment. Inhibition of the proteasome is associated with alteration of a number of important biological processes leading, in consequence, to inhibition of angiogenesis. The effect of drugs in this group and the degree of patient response to the treatment used is itself an extremely complex process that depends on many factors. At cellular level the change in sensitivity to proteasome inhibitors may be related to differences in the expression level of proteasome subunits, the degree of proteasome loading, metabolic adaptation, transcriptional or epigenetic factors. These are just some of the possibilities that may influence differences in response to proteasome inhibitors. This review describes the main cellular factors that determine the degree of response to proteasome inhibitor drugs, as well as information on the key role of the proteasome and the performance characteristics of the inhibitors that are the mainstay of multiple myeloma treatment.

Expression of Ferroptosis-Related Proteins Glutathione Peroxidase 4, Nuclear Factor Erythroid 2-Related Factor 2, and Solute Carrier Family 7 Member 11 in Gastric Cancer Patients

BACKGROUND/AIMS

The aim of this study was to investigate the expression of ferroptosis-related targets glutathione peroxidase 4, nuclear factor erythroid 2-related factor 2, and solute carrier family 7 member 11 in gastric cancer and the correlation between their expression and the clinicopathological characteristics and prognosis of gastric cancer patients.

MATERIALS AND METHODS

Forty-two gastric cancer samples and paracancerous samples were included, and all cases were detected with glutathione peroxidase 4, nuclear factor erythroid 2-related factor 2, and solute carrier family 7 member 11 by immunohistochemistry. Six gastric cancer cell lines and 1 normal gastric epithelial cell were stably cultured, and the expression of target genes of different cell lines was detected using western blot and polymerase chain reaction. Public data were downloaded from the database, and analyses were performed by software including Statistical Package for the Social Sciences and Prism.

RESULTS

A high glutathione peroxidase 4 expression level was found in 7 (16.67%) cancer tissues and 0 (0.00%) paracancerous tissues (P = .012). Nuclear factor erythroid 2-related factor 2 was upregulated in 23 (54.76%) cancer tissues and 2 (4.76%) paracancerous tissues (P < .001). Solute carrier family 7 member 11 showed increased expression in 4 (9.52%) cancer tissues and 1 (2.38%) paracancerous tissue (P = .356). No significant association existed between their expression and the clinicopathological characteristics and prognosis of gastric cancer patients. Glutathione peroxidase 4 and nuclear factor erythroid 2-related factor 2 expressions were higher in all 6 gastric cancer cell lines compared to normal gastric epithelial cells.

CONCLUSION

Glutathione peroxidase 4 and nuclear factor erythroid 2-related factor 2 expressions were significantly higher in gastric cancer, which may be potential biomarkers of gastric cancer.

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.

Knockout of NRF2 triggers prostate cancer cells death through ROS modulation and sensitizes to cisplatin

Prostate cancer (PCa) represents the second most common cancer in men and affects millions worldwide. Chemotherapy is a common treatment for PCa but the development of resistance is often a problem during therapy. NRF2 (nuclear factor erythroid 2-related factor 2) is one of the major transcription factors regulating antioxidant enzymes and is also involved with drug efflux and detoxification. Cancer cells submitted to chemotherapy often promote NRF2 activation to benefit themselves with the cytoprotective response. Here, we found that DU145 and PC3 PCa cell lines have different responses regarding NRF2 activation, when subjected to arsenite-induced stress, even in the presence of MG132, a proteasome inhibitor. We also observed that only in PC3 cells treated with arsenite, NRF2 was able to translocate to the nucleus. To better understand the role of NRF2 in promoting chemoresistance, we performed CRISPR knockout of NRF2 (NKO) in DU145 and PC3 cells. The effectiveness of the knockout was confirmed through the downregulation of NRF2 targets (p < 0.0001). PC3 NKO cells exhibited higher levels of reactive oxygen species (ROS) compared to wild-type cells (p < 0.0001), while this alteration was not observed in DU145 NKO cells. Despite no modulation in ROS content, a lower IC50 value (p < 0.05) for cisplatin was observed in DU145 NKO cells, suggesting that the knockout sensitized the cells to the treatment. Besides, the treatment of DU145 NKO with cisplatin led cells to apoptosis as observed by the increased levels of PARP1 cleavage (p < 0.05), possibly triggered by increased DNA damage. Reduced levels of KU70 and phospho-CHK2 (p < 0.05) were also detected. The data presented here support that NRF2 is a mediator of oncogenesis and could be a potential target to sensitize PCa cells to chemotherapy, reinforcing the importance of knowing the specific genetic and biochemical characteristics of the cancer cells for a more effective approach against cancer.

Ferroptosis and chronic gastritis and gastric cancer

As a unique form of cell death in the context of redox, ferroptosis has become a hot research topic in recent years for its potential anti-tumor effect. Digestive system diseases are a common group of human diseases. Increasing studies have addressed the important role of ferroptosis in digestive system diseases. Here, we discuss the mechanism of ferroptosis, and analyze the role of ferroptosis in chronic gastritis and gastric cancer. Targeting ferroptosis may be one of the directions for the treatment of digestive system diseases.

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.

Application of ARE-reporter systems in drug discovery and safety assessment

The human body is continuously exposed to xenobiotics and internal or external oxidants. The health risk assessment of exogenous chemicals remains a complex and challenging issue. Alternative toxicological test methods have become an essential strategy for health risk assessment. As a core regulator of constitutive and inducible expression of antioxidant response element (ARE)-dependent genes, nuclear factor erythroid 2-related factor 2 (Nrf2) plays a critical role in maintaining cellular redox homeostasis. Consistent with the properties of Nrf2-mediated antioxidant response, Nrf2-ARE activity is a direct indicator of oxidative stress and thus has been used to identify and characterize oxidative stressors and redox modulators. To screen and distinguish chemicals or environmental insults that affect the cellular antioxidant activity and/or induce oxidative stress, various in vitro cell models expressing distinct ARE reporters with high-throughput and high-content properties have been developed. These ARE-reporter systems are currently widely applied in drug discovery and safety assessment. In the present review, we provide an overview of the basic structures and applications of various ARE-reporter systems employed for discovering Nrf2-ARE modulators and characterizing oxidative stressors.

Mesenchymal gene expression subtyping analysis for early-stage human papillomavirus-negative head and neck squamous cell carcinoma reveals prognostic and predictive applications

Patients with oral cavity squamous cell carcinoma (OCSCC) are predominantly human papillomavirus (HPV)(−), and treatment typically involves surgical resection ± neck dissection, followed by radiation ± chemotherapy. We previously described four mRNA expression patterns (classical, atypical, basal, and mesenchymal), each with unique genomic features and prognosis. Here, we examine the clinical utility of gene expression subtyping in head and neck squamous cell carcinoma (HNSCC) and introduce potentially predictive applications in HPV(−) OCSCC. A retrospective genomic database analysis was performed including 562 HNSCC patients from MD Anderson (MDA-GSE41116) and The Cancer Genome Atlas (TCGA). Samples were assigned molecular subtypes (classical, atypical, basal, and mesenchymal) using an 88-gene classifier. HPV status was determined by gene expression. The clinical endpoint was overall survival censured at 36 months. The Kaplan–Meier plots and log-rank tests were used to investigate associations between clinical variables and survival. Of the 418 TCGA training patients who met analysis criteria, nearly 20% presented as stage I/II. Among node(−) OCSCC patients, the mesenchymal subtype is associated with worse survival (hazard ratio (HR) = 2.4, p = 0.021), offering a potentially actionable biomarker in otherwise early-stage, low-risk disease. This was confirmed in the MDA validation cohort. Node(−) non-mesenchymal OCSCC patients had far better survival compared to node(−) mesenchymal, and all node(+) patients had similarly poor survival. These findings suggest that the mesenchymal subtype is associated with poor survival in surgically resected, early-stage, node(−) OCSCC otherwise expected to have favorable outcomes. These findings highlight the potential value of gene expression subtyping as a pathology adjunct for prognostication and treatment decision-making in OCSCC patients.

Expression of ferroptosis-related gene correlates with immune microenvironment and predicts prognosis in gastric cancer

The study is to explore the role of ferroptosis-related genes (FRGs) in the occurrence and development of gastric cancer (GC), and to construct a new prognosis signature to predict the prognosis in GC. Clinical information and corresponding RNA data of GC patients were downloaded from TCGA and GEO databases. Consensus clustering was performed to identify new molecular subgroups. ESTIMATE, CIBERSORT, McpCounter and TIMER algorithm were used to analyze the infiltration of immune cells in two molecular subgroups. LASSO algorithm and multivariate Cox analysis were used to construct a prognostic risk signature. Functional analysis was conducted to elucidate the underlying mechanisms. Finally, the FRPGs were verified by Quantitative Real-Time PCR. We obtained 16 FRGs and divided GC patients into two subgroups by consistent clustering. Cluster C1 with a higher abundance of immune cell infiltration but lower probability in response to immunotherapy, it was reasonable to speculate that Cluster C1 was in accordance with the immune rejection type. Functional analysis showed that the biological process of DEGs in training cohort mainly included immune globulin, and human immune response mediated by circulating immune globulin. GSEA analysis showed that compared with Cluster C2, Cluster C1 showed lower expression in lipid metabolism. The nomogram combined with risk signature and clinical features can accurately predict the prognosis of GC patients. We identified two molecular subtypes, Clusters C1 and C2. In Cluster C1, patients with poor prognosis present with a hyperimmune status and low lipid metabolism, and we speculate that Cluster C1 was in accordance with the immune rejection type. The risk model based on FRPGs can accurately predict the prognosis of GC. These results indicated that ferroptosis is associated with TIME, and deserved considerable attention in determining immunotherapy treatment strategy for GC patients.

Abnormal phenotype of Nrf2 is associated with poor prognosis through hypoxic/VEGF-A-Rap1b/VEGFR2 pathway in gastric cancer

Metastasis is the major cause of death in gastric cancer patients and altered expression of Nrf2 is associated with cancer development. This study assessed Nrf2 and HO-1 expression and hypoxia-induced Nrf2 expression in the promotion of metastatic potential of gastric cancer cells, the relationship of Rap1b and Nrf2 was also discussed. Nrf2 and HO-1 expression were significantly associated with clinicopathological characteristic and were independent prognostic predictors in gastric cancer patients. Hypoxia up-regulated the expression of Nrf2, HO-1 and HIF-1α, whereas knockdown of Nrf2 inhibited cell invasion capacity and reduced the expression of Nrf2, HO-1 and HIF-1α. Patients in the Rap1b (+) Nrf2 (+) group had worst overall survival compared with those from other groups. Knockdown of Rap1b and Nrf2 significantly inhibited cell invasion capacity in the common group compared with the other groups. Hypoxia or VEGF-A facilitated the nuclear translocation of Nrf2 through Rap1b or VEGFR2. Hypoxia or VEGF-A did not induce the phosphorylation of P-Erk1/2 and P-Akt after knockdown of Rap1b or VEGFR2. Hypoxia promoted the gastric cancer malignant behavior through the upregulation of Rap1b and Nrf2. Hypoxia/VEGF-A-Rap1b/VEGFR2 facilitated the nuclear translocation of Nrf2. Targeting Rap1b and Nrf2 may be a novel therapeutic strategy for gastric cancer.

Inhibition of USP11 sensitizes gastric cancer to chemotherapy via suppressing RhoA and Ras-mediated signaling pathways

BACKGROUND

The poor outcomes in advanced gastric cancer (GC) necessitate alternative therapeutic strategy. Ubiquitin-specific protease 11 (USP11) has recently garnered attention as a therapeutic target in cancer because of its important regulatory role in cancer cell functions. Here, we revealed the expression, function and underlying molecular interactions of USP11 in gastric cancer.

METHODS

The expression of USP11 was analyzed using immunohistochemistry and ELISA. The loss-of function and gain-of function analysis of USP11 was performed using siRNA knockdown and plasmid overexpression approaches. The downstream molecules regulated by USP11 were determined using immunoblotting analysis.

RESULTS

USP11 was upregulated in ∼80% of gastric cancer patients, and the upregulation was associated with HER3 overexpression. In addition, USP11 level was not regulated by HER3 and vice versa. Functional studies demonstrated that USP11 overexpression promoted gastric cancer growth and migration, and alleviated toxicity-induced by chemotherapeutic drug. In contrast, USP11 depletion significantly inhibited gastric cancer growth, migration and survival, and augmented chemotherapeutic drug's efficacy. Gastric cancer cells with higher USP11 levels were more sensitive to USP11 inhibitions than cells with lower USP11 levels. Mechanism studies showed that USP11 depletion suppressed migration via RhoA-mediated pathway and inhibited growth and survival likely via Ras-mediated pathway.

CONCLUSIONS

Our work highlights the important role of USP11 in gastric cancer and therapeutic value of inhibiting USP11 to sensitize gastric cancer to chemotherapy.

Overview of Ferroptosis and Synthetic Lethality Strategies

Ferroptosis, a term first proposed in 2012, is iron-dependent, non-apoptotic regulatory cell death induced by erastin. Ferroptosis was originally discovered during synthetic lethal screening for drugs sensitive to RAS mutant cells, and is closely related to synthetic lethality. Ferroptosis sensitizes cancer stem cells and tumors that undergo epithelial−mesenchymal transition and are resistant to anticancer drugs or targeted therapy. Therefore, ferroptosis-inducing molecules are attractive new research targets. In contrast, synthetic lethal strategies approach mechanisms and genetic abnormalities that cannot be directly targeted by conventional therapeutic strategies, such as RAS mutations, hypoxia, and abnormalities in the metabolic environment. They also target the environment and conditions specific to malignant cells, have a low toxicity to normal cells, and can be used in combination with known drugs to produce new ones. However, the concept of synthetic lethality has not been widely adopted with ferroptosis. In this review, we surveyed the literature on ferroptosis-related factors and synthetic lethality to examine the potential therapeutic targets in ferroptosis-related molecules, focusing on factors related to synthetic lethality, discovery methods, clinical application stages, and issues in drug discovery.

Correlation of alterations in the KEAP1/CUL3/NFE2L2 pathway with radiation failure in larynx squamous cell carcinoma

OBJECTIVES

Patients with laryngeal squamous cell carcinoma (LSCC) often fail radiation therapy (RT), when received as monotherapy or in combination with other treatment modalities. Mechanisms for RT failure are poorly understood. We hypothesized that tumors failing RT would have increased rates of somatic mutations in genes associated with radiation resistance, particularly in genes associated with the NFE2L2 oxidative stress pathway. Using targeted exome sequencing on pretreated LSCC tumors, we retrospectively compared somatic mutation profile with clinical data and response to treatment.

METHODS

Tumors were classified as either radiation-resistant (RR) or radiation-sensitive (RS). RR was defined as persistent or recurrent disease within 2 years of receiving full-dose RT. Early stage (ES) LSCC was defined as Stage I or II tumors without lymph node involvement. Eight genes associated with radiation resistance were prioritized for analysis. RT-qPCR was performed on five NFE2L2 pathway genes.

RESULTS

Twenty LSCC tumors were included and classified as either RR (n = 8) or RS (n = 12). No differences in individual rates of somatic mutations by genes associated with radiation resistance were identified. Higher rates of total mutational burden (TMB) and increased alterations associated with the NFE2L2 pathway was observed in RR vs RS tumors (P < .05). In an analysis of only ES-LSCC patients (RR, n = 3 and RS, n = 3), RR tumors had increased NFE2L2 somatic pathway mutations (P = .014) and increased NQO1 mRNA expression (P = .05).

CONCLUSION

Increased TMB and NFE2L2 pathway alterations were associated with radiation resistance in LSCC. NQO1 mRNA expression may serve as a biomarker for RT response in ES-LSCC.Level of Evidence: II1.

Molecular mechanisms of pulmonary carcinogenesis by polycyclic aromatic hydrocarbons (PAHs): Implications for human lung cancer

Lung cancer has the second highest incidence and highest mortality compared to all other cancers. Polycyclic aromatic hydrocarbon (PAH) molecules belong to a class of compounds that are present in tobacco smoke, diesel exhausts, smoked foods, as well as particulate matter (PM). PAH-derived reactive metabolites are significant contributors to lung cancer development. The formation of these reactive metabolites entails metabolism of the parent PAHs by cytochrome P4501A1/1B1 (CYP1A1/1B1) and epoxide hydrolase enzymes. These reactive metabolites then react with DNA to form DNA adducts, which contribute to key gene mutations, such as the tumor suppressor gene, p53 and are linked to pulmonary carcinogenesis. PAH exposure also leads to upregulation of CYP1A1 transcription by binding to the aryl hydrocarbon receptor (AHR) and eliciting transcription of the CYP1A1 promoter, which comprises specific xenobiotic-responsive element (XREs). While hepatic and pulmonary CYP1A1/1B1 metabolize PAHs to DNA-reactive metabolites, the hepatic CYP1A2, however, may protect against lung tumor development by suppressing both liver and lung CYP1A1 enzymes. Further analysis of these enzymes has shown that PAH-exposure also induces sustained transcription of CYP1A1, which is independent of the persistence of the parent PAH. CYP1A2 enzyme plays an important role in the sustained induction of hepatic CYP1A1. PAH exposure may further contribute to pulmonary carcinogenesis by producing epigenetic alterations. DNA methylation, histone modification, long interspersed nuclear element (LINE-1) activation, and non-coding RNA, specifically microRNA (miRNA) alterations may all be induced by PAH exposure. The relationship between PAH-induced enzymatic reactive metabolite formation and epigenetic alterations is a key area of research that warrants further exploration. Investigation into the potential interplay between these two mechanisms may lead to further understanding of the mechanisms of PAH carcinogenesis. These mechanisms will be crucial for the development of effective targeted therapies and early diagnostic tools.

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.

Quinone oxidoreductase 1 is overexpressed in gastric cancer and associated with outcome of adjuvant chemotherapy and survival

BACKGROUND

Quinine oxidoreductase 1 (NQO1) plays a vital role in protecting normal cells against oxidative damage and electrophilic attack. It is highly expressed in many solid tumors, suggesting a role in cancer development and progression. However, the role of NQO1 in gastric cancer and its effect on cancer development and prognosis have not been fully investigated.

AIM

To investigate the clinical relevance of NQO1 protein expression in gastric cancer and to explore the potential of NQO1 to serve as a prognostic biomarker and therapeutic target.

METHODS

In this retrospective study, gastric cancer specimens of 175 patients who were treated between 1995 and 2011 were subjected to immunohistochemistry analyses for NQO1. The correlation of NQO1 expression with gastric cancer prognosis and clinical and pathological parameters was investigated.

RESULTS

NQO1 protein was overexpressed in 59.43% (104/175) of the analyzed samples. Overexpression of NQO1 was associated with a significantly inferior prognosis. In addition, multivariate analysis suggested that NQO1 overexpression, along with tumor stage and patient age, are prominent prognostic biomarkers for gastric cancer. Moreover, NQO1 overexpression was correlated to a better response to 5-fluorouracil (5-FU)-based adjuvant chemotherapy.

CONCLUSION

NQO1 overexpression is associated with a significantly poor prognosis and better response to 5-FU in patients with gastric cancer. These findings are relevant for improving therapeutic approaches for gastric cancer patients.

sMicroRNA-28-5p acts as a metastasis suppressor in gastric cancer by targeting Nrf2

The transcription factor nuclear factor (erythroid-2)-related factor 2 (Nrf2) can principally serve a mode of protection for both the normal cells and cancer cells from cellular stress, and elevates cancer cell survival. microRNA-28 (miR-28) has been involved in the regulation of Nrf2 expression in breast epithelial cells. However, no comprehensive analysis has been conducted regarding the function of miR-28-5p regulating Nrf2 in gastric cancer (GC). In this study, we aimed to evaluate their interaction and biological roles in the migration and invasion of GC cells. The expression of Nrf2 in the cancer tissues harvested from 42 patients with GC was examined by an array of molecular techniques comprising of Immunohistochemical staining, RT-qPCR and Western blot analysis. Kaplan-Meier method was adopted for analysis of the correlation of Nrf2 with the prognosis of GC patients. Interaction between miR-28-5p and Nrf2 was determined using the bioinformatics analysis and dual luciferase reporter gene assay. Gain- and loss-of-function studies of miR-28-5p and Nrf2 were conducted to elucidate their effects on GC cell migration, invasion and metastasis, as well as expression pattern of several epithelial-mesenchymal transition (EMT)-related proteins. Results indicated that the expression pattern of Nrf2 was significantly upregulated in GC tissues and indicative of poor prognosis of GC patients. miR-28-5p was verified to target Nrf2 and downregulate its expression. GC cells with overexpression of miR-28-5p or Nrf2 knockdown exhibited a marked reduction in the migrated and invasive abilities, along with the N-cadherin expression yet an increase of E-cadherin expression. Furthermore, miR-28-5p exerted an inhibitory function on the metastatic and tumorigenicity of GC cells. In conclusion, miR-28-5p is a comprehensive tumor suppressor that inhibits GC cell migration and invasion through repressing the Nrf2 expression. Therefore, miR-28-5p may serve as a potential biomarker for the prognosis of GC and a novel therapeutic target in advanced GC.

P62/SQSTM1/Keap1/NRF2 Axis Reduces Cancer Cells Death-Sensitivity in Response to Zn(II)-Curcumin Complex

The hyperactivation of nuclear factor erythroid 2 p45-related factor 2 (NRF2), frequently found in many tumor types, can be responsible for cancer resistance to therapies and poor patient prognosis. Curcumin has been shown to activate NRF2 that has cytotprotective or protumorigenic roles according to tumor stage. The present study aimed at investigating whether the zinc–curcumin Zn(II)–curc compound, which we previously showed to display anticancer effects through multiple mechanisms, could induce NRF2 activation and to explore the underlying molecular mechanisms. Biochemical studies showed that Zn(II)–curc treatment increased the NRF2 protein levels along with its targets, heme oxygenase-1 (HO-1) and p62/SQSTM1, while markedly reduced the levels of Keap1 (Kelch-like ECH-associated protein 1), the NRF2 inhibitor, in the cancer cell lines analyzed. The silencing of either NRF2 or p62/SQSTM1 with specific siRNA demonstrated the crosstalk between the two molecules and that the knockdown of either molecule increased the cancer cell sensitivity to Zn(II)–curc-induced cell death. This suggests that the crosstalk between p62/SQSTM1 and NRF2 could be therapeutically exploited to increase cancer patient response to therapies.

Sustained high expression of NRF2 and its target genes induces dysregulation of cellular proliferation and apoptosis is associated with arsenite-induced malignant transformation of human bronchial epithelial cells

In arsenic toxicity, activation of the erythroid 2-related factor 2 (NRF2) pathway is regarded as a driver of cancer development and progression; however, the mechanisms by which NRF2 gene expression regulates cell cycle progression and mediates pathways of cellular proliferation and apoptosis in arsenic-induced lung carcinogenesis are poorly understood. In this study, we explored the regulatory functions of NRF2 expression and its target genes in immortalized human bronchial epithelial (HBE) cells continuously exposed to 1.0 μM sodium arsenite over approximately 43 passages (22 weeks). The experimental treatment induced malignant transformation in HBE cells, characterized by increased cellular proliferation and soft agar clone formation, as well as cell migration, and accelerated cell cycle progression from G0/G1 to S phase with increased levels of cyclin E-CDK2 complex,decreased cellular apoptosis rate. Moreover, we observed a sustained increase in NRF2 protein levels and those of its target gene products (NQO1, BCL-2) with concurrently decreased expression of apoptosis-related proteins (BAX, Cleaved-caspase-3/Caspase-3 and CHOP) and increased expression of the anti-apoptotic protein MCL-1. Silencing NRF2 expression with small interfering RNA (siRNA) in arsenite-transformed (T-HBE) cells was shown to reverse the malignant phenotype. Further, siRNA silencing of NQO1 significantly decreased levels of the cyclin E-CDK2 complex, inhibiting G0/G1 to S phase cell cycle progression and transformation to the T-HBE phenotypes. This study demonstrated a novel role for the NRF2/NQO1 signaling pathway in mediating arsenite-induced cell transformation by increasing the expression of cyclin E-CDK2, and accelerating the cell cycle and cell proliferation. Arsenite promotes activation of the NRF2/BCL-2 signaling pathway inhibited CHOP increasing cellular resistance to apoptosis and further promoting malignant transformation.

NRF2-Dependent Bioactivation of Mitomycin C as a Novel Strategy To Target KEAP1-NRF2 Pathway Activation in Human Cancer

Activating mutations in the KEAP1-NRF2 pathway are found in approximately 25% of lung tumors, where the hijacking of NRF2's cytoprotective functions results in aggressive tumor growth, chemoresistance, and a poor prognosis for patients. There are currently no approved drugs which target aberrant NRF2 activation, which means that there is an urgent clinical need to target this orphan oncogenic pathway in human tumors. In this study, we used an isogenic pair of wild-type and Keap1 knockout cells to screen a range of chemotherapeutic and pathway-targeted anticancer drugs in order to identify compounds which display enhanced toxicity toward cells with high levels of Nrf2 activity. Through this approach, complemented by validation across a panel of eight human cancer cell lines from a range of different tissues, we identified the DNA-damaging agent mitomycin C to be significantly more toxic in cells with aberrant Nrf2 activation. Mechanistically, we found that the NRF2 target genes for cytochrome P450 reductase, NQO1, and enzymes in the pentose phosphate pathway are all responsible for the NRF2-dependent enhanced bioactivation of mitomycin C. As mitomycin C is already approved for clinical use, it represents as excellent drug repositioning candidate to target the currently untreatable NRF2 activation in human tumors.

A predictive model for assessing prognostic risks in gastric cancer patients using gene expression and methylation data

BACKGROUND

The role(s) of epigenetic reprogramming in gastric cancer (GC) remain obscure. This study was designed to identify methylated gene markers with prognostic potential for GC.

METHODS

Five datasets containing gene expression and methylation profiles from GC samples were collected from the GEO database, and subjected to meta-analysis. All five datasets were subjected to quality control and then differentially expressed genes (DEGs) and differentially expressed methylation genes (DEMGs) were selected using MetaDE. Correlations between gene expression and methylation status were analysed using Pearson coefficient correlation. Then, enrichment analyses were conducted to identify signature genes that were significantly different at both the gene expression and methylation levels. Cox regression analyses were performed to identify clinical factors and these were combined with the signature genes to create a prognosis-related predictive model. This model was then evaluated for predictive accuracy and then validated using a validation dataset.

RESULTS

This study identified 1565 DEGs and 3754 DEMGs in total. Of these, 369 were differentially expressed at both the gene and methylation levels. We identified 12 signature genes including VEGFC, FBP1, NR3C1, NFE2L2, and DFNA5 which were combined with the clinical data to produce a novel prognostic model for GC. This model could effectively split GC patients into two groups, high- and low-risk with these observations being confirmed in the validation dataset.

CONCLUSION

The differential methylation of the 12 signature genes, including VEGFC, FBP1, NR3C1, NFE2L2, and DFNA5, identified in this study may help to produce a functional predictive model for evaluating GC prognosis in clinical samples.

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.

Inhibition of Nrf2/HO-1 signaling pathway by Dextran Sulfate suppresses angiogenesis of Gastric Cancer

Purpose: To investigate the role of Nrf2/HO-1 signaling pathway in angiogenesis and whether dextran sulfate (DS) could suppress angiogenesis by inhibiting Nrf2/HO-1 signaling pathway in gastric cancer.

Methods:In vitro; Western blot analyzed the expression of Nrf2 in gastric cell lines. Tube formation assay observed the effect of gradient concentration DS on the angiogenic potential of HGC-27 cells. Immunofluorescence,western blot and qPCR analyzed the effects of DS on the expression of Nrf2, HO-1 and VEGF under gradient hypoxia time. Immunofluorescence,western blot,qPCR and tube formation assay analyzed the effects of up-regulating or down-regulating Nrf2/HO-1 signaling pathway on VEGF expression and angiogenic potential in HGC-27 cells. In vivo: Construct nude mouse intraperitoneal implantation metastasis model. Immunohistochemistry and western blot analyzed the effects of DS on the expression of Nrf2, HO-1, VEGF and MVD in nude mice. Immunohistochemistry detected the expression of Nrf2, HO-1, VEGF and MVD in human paracancerous tissue and gastric cancer tissues with different degrees of differentiation.

Results: The expression of Nrf2 increased most significantly in HGC-27 cell line. DS reduced the angiogenic potential and the expression of Nrf2, HO-1 and VEGF in HGC-27 cells. Down-regulation of Nrf2/HO-1 signaling pathway decreased VEGF expression and angiogenic potential in HGC-27 cells. Up-regulation of Nrf2/HO-1 signaling pathway increased VEGF expression and angiogenic potential in HGC-27 cells. DS reduced the expression of Nrf2, HO-1, VEGF and MVD in nude mice. Nrf2, HO-1, VEGF and MVD showed low expression in paracancerous tissue but high expression in gastric cancer tissues. They were weak, moderate and strong in well, moderately and poorly differentiated gastric cancer tissues, respectively.

Conclusion: Nrf2/HO-1 signaling pathway may positively regulate gastric cancer angiogenesis and DS may suppress the angiogenesis by inhibiting Nrf2/HO-1 signaling pathway in gastric cancer.

NRF2 and the Ambiguous Consequences of Its Activation during Initiation and the Subsequent Stages of Tumourigenesis

NF-E2 p45-related factor 2 (NRF2, encoded in the human by NFE2L2) mediates short-term adaptation to thiol-reactive stressors. In normal cells, activation of NRF2 by a thiol-reactive stressor helps prevent, for a limited period of time, the initiation of cancer by chemical carcinogens through induction of genes encoding drug-metabolising enzymes. However, in many tumour types, NRF2 is permanently upregulated. In such cases, its overexpressed target genes support the promotion and progression of cancer by suppressing oxidative stress, because they constitutively increase the capacity to scavenge reactive oxygen species (ROS), and they support cell proliferation by increasing ribonucleotide synthesis, serine biosynthesis and autophagy. Herein, we describe cancer chemoprevention and the discovery of the essential role played by NRF2 in orchestrating protection against chemical carcinogenesis. We similarly describe the discoveries of somatic mutations in NFE2L2 and the gene encoding the principal NRF2 repressor, Kelch-like ECH-associated protein 1 (KEAP1) along with that encoding a component of the E3 ubiquitin-ligase complex Cullin 3 (CUL3), which result in permanent activation of NRF2, and the recognition that such mutations occur frequently in many types of cancer. Notably, mutations in NFE2L2, KEAP1 and CUL3 that cause persistent upregulation of NRF2 often co-exist with mutations that activate KRAS and the PI3K-PKB/Akt pathway, suggesting NRF2 supports growth of tumours in which KRAS or PKB/Akt are hyperactive. Besides somatic mutations, NRF2 activation in human tumours can occur by other means, such as alternative splicing that results in a NRF2 protein which lacks the KEAP1-binding domain or overexpression of other KEAP1-binding partners that compete with NRF2. Lastly, as NRF2 upregulation is associated with resistance to cancer chemotherapy and radiotherapy, we describe strategies that might be employed to suppress growth and overcome drug resistance in tumours with overactive NRF2.

Crocin reverses 1-methyl-3-nitroso-1-nitroguanidine (MNNG)-induced malignant transformation in GES-1 cells through the Nrf2/Hippo signaling pathway

BACKGROUND

Crocin, an active constituent of saffron, has anticancer activity. In this study, we investigated the relationship of Crocin with human gastric epithelial cells induced by 1-methyl-3-nitroso-1-nitroguanidine (MNNG), and explored the underlying mechanism.

METHODS

In vivo, the animal growth and atypical hyperplasia were observed in Sprague-Dawley rats. A cell model was established by treating the human gastric mucosa epithelial cell line GES-1 with MNNG. The effects of Crocin on proliferation, cell cycle, apoptosis, and epithelial-mesenchymal transition (EMT) in GES-1 cells were analyzed using Cell Counting Kit-8, colony formation, flow cytometry, and Transwell assay, respectively. Western blot was used to explore the potential mechanism..

RESULTS

The gastric mucosa of animal model deteriorated obviously, the weight growth rate slowed down, and the atypical hyperplasia of gastric mucosa increased. The GES-1 cells had characteristics of malignant cells such as proliferation, apoptosis, and metastasis ability. It was found that Crocin suppressed the cell proliferation, increased apoptosis, and blocked the cycle arrest in G0/G1 phase simultaneously. Furthermore, Crocin negatively regulated the invasion ability of MNNG-treated GES-1 cells and EMT process. Crocin also increased the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1), decreased TAZ in MNNG-treated GES-1 cells. Interestingly, Crocin regulated the expression of TAZ and yes-associated protein (YAP) by increasing Nrf2 level, as well as their upstream targets, mercaptopyruvate sulfurtransferase (MST) and large tumor suppressor (LATS).

CONCLUSIONS

Crocin protected against MNNG-induced malignant transformation through the Nrf2/Hippo signaling pathway, which might be a drug candidate for clinical gastric cancer management.

The NRF2, Thioredoxin, and Glutathione System in Tumorigenesis and Anticancer Therapies

Cancer remains an elusive, highly complex disease and a global burden. Constant change by acquired mutations and metabolic reprogramming contribute to the high inter- and intratumor heterogeneity of malignant cells, their selective growth advantage, and their resistance to anticancer therapies. In the modern era of integrative biomedicine, realizing that a personalized approach could benefit therapy treatments and patients' prognosis, we should focus on cancer-driving advantageous modifications. Namely, reactive oxygen species (ROS), known to act as regulators of cellular metabolism and growth, exhibit both negative and positive activities, as do antioxidants with potential anticancer effects. Such complexity of oxidative homeostasis is sometimes overseen in the case of studies evaluating the effects of potential anticancer antioxidants. While cancer cells often produce more ROS due to their increased growth-favoring demands, numerous conventional anticancer therapies exploit this feature to ensure selective cancer cell death triggered by excessive ROS levels, also causing serious side effects. The activation of the cellular NRF2 (nuclear factor erythroid 2 like 2) pathway and induction of cytoprotective genes accompanies an increase in ROS levels. A plethora of specific targets, including those involved in thioredoxin (TRX) and glutathione (GSH) systems, are activated by NRF2. In this paper, we briefly review preclinical research findings on the interrelated roles of the NRF2 pathway and TRX and GSH systems, with focus given to clinical findings and their relevance in carcinogenesis and anticancer treatments.

MiR-27b-3p exerts tumor suppressor effects in esophageal squamous cell carcinoma by targeting Nrf2

MiR-27b-3p has been reported to function as tumor suppressor in several tumors, including breast cancer and lung cancer. Recently, miR-27b-3p has been identified to be significantly down-regulated in esophageal cancer. However, the clinical significance and biological role of miR-27b-3p in esophageal squamous cell carcinoma (ESCC) still remain unclear. In this study, the expression levels of miR-27b-3p were significantly reduced in ESCC clinical tissues and ESCC cell lines (EC97069 and TE-1). Moreover, down-regulated expression of miR-27b-3p was associated with poor cell differentiation, TNM stage and lymph node metastasis. Specially, overexpression of miR-27b-3p significantly suppressed cell proliferation, migration and invasion in vitro using CCK-8 and transwell assays. Targetscan bioinformatics predictions and luciferase reporter assay confirmed that nuclear factor erythroid 2-related factor 2 (NFE2L2, Nrf2) was a direct target gene of miR-27b-3p. Nrf2 expression was significantly increased in ESCC tissues compared with adjacent tissues. Up-regulated expression of Nrf2 was correlated with TNM stage and lymph node metastasis. Functionally, knockdown of Nrf2 exhibited similar effects to overexpression of miR-27b-3p. Higher expression of ZO-1, E-cadherin and lower expression of N-cadherin, Vimentin and Claudin-1 were observed after miR-27b-3p overexpression of Nrf2 knockdown. Rescue experiments proved that miR-27b-3p suppressed cell proliferation, migration, invasion and epithelial to mesenchymal transition (EMT) via suppression of Nrf2. Taken together, the newly identified miR-27b-3p/Nrf2 axis might represent a new candidate therapeutic target for ESCC treatment.

Pathogenesis and anti-proliferation mechanisms of Crocin in human gastric carcinoma cells

Gastric cancer is the fourth most common cause of cancer death globally and the second most common in Asia. Many studies suggest that Crocin has the potential for gastric cancer antineoplastic combined chemotherapy protocols. Here we investigated genomic changes related to the inhibitory effect of Crocin, and elucidated the molecular mechanism of this inhibition in gastric carcinoma cells. We found that, compared with the control group, 216 significantly upregulated and 301 significantly downregulated genes were identified in Crocin-treated AGS cells. Many of these differentially expressed genes in AGS cells are involved in Nrf2-mediated oxidative stress response, p53 signaling, and integrin signaling, which suggested the mechanism of Crocin functions in therapy of gastric cancer. In summary, our study indicates that Crocin has the potential for gastric cancer adjuvant treatment through reducing cell oxidative stress levels.

The Role of Nrf2 Activity in Cancer Development and Progression

Nrf2 is a transcription factor that stimulates the expression of genes which have antioxidant response element-like sequences in their promoter. Nrf2 is a cellular protector, and this principle applies to both normal cells and malignant cells. While healthy cells are protected from DNA damage induced by reactive oxygen species, malignant cells are defended against chemo- or radiotherapy. Through our literature search, we found that Nrf2 activates several oncogenes unrelated to the antioxidant activity, such as Matrix metallopeptidase 9 (MMP-9), B-cell lymphoma 2 (BCL-2), B-cell lymphoma-extra large (BCL-xL), Tumour Necrosis Factor α (TNF-α), and Vascular endothelial growth factor A (VEGF-A). We also did a brief analysis of The Cancer Genome Atlas (TCGA) data of lung adenocarcinoma concerning the effects of radiation therapy and found that the therapy-induced Nrf2 activation is not universal. For instance, in the case of recurrent disease and radiotherapy, we observed that, for the majority of Nrf2-targeted genes, there is no change in expression level. This proves that the universal, axiomatic rationale that Nrf2 is activated as a response to chemo- and radiation therapy is wrong, and that each scenario should be carefully evaluated with the help of Nrf2-targeted genes. Moreover, there were nine genes involved in lipid peroxidation, which showed underexpression in the case of new radiation therapy: ADH1A, ALDH3A1, ALDH3A2, ADH1B, GPX2, ADH1C, ALDH6A1, AKR1C3, and NQO1. This may relate to the fact that, while some studies reported the co-activation of Nrf2 and other oncogenic signaling pathways such as Phosphoinositide 3-kinases (PI3K), mitogen-activated protein kinase (MAPK), and Notch1, other reported the inverse correlation between Nrf2 and the tumor-promoter Transcription Factor (TF), Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). Lastly, Nrf2 establishes its activity through interactions at multiple levels with various microRNAs. MiR-155, miR-144, miR-28, miR-365-1, miR-93, miR-153, miR-27a, miR-142, miR-29-b1, miR-340, and miR-34a, either through direct repression of Nrf2 messenger RNA (mRNA) in a Kelch-like ECH-associated protein 1 (Keap1)-independent manner or by enhancing the Keap1 cellular level, inhibit the Nrf2 activity. Keap1–Nrf2 interaction leads to the repression of miR-181c, which is involved in the Nuclear factor kappa light chain enhancer of activated B cells (NF-κB) signaling pathway. Nrf2’s role in cancer prevention, diagnosis, prognosis, and therapy is still in its infancy, and the future strategic planning of Nrf2-based oncological approaches should also consider the complex interaction between Nrf2 and its various activators and inhibitors.

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.

Pharmacological Applications of Nrf2 Inhibitors as Potential Antineoplastic Drugs

Oxidative stress (OS) is associated with many diseases ranging from cancer to neurodegenerative disorders. Nuclear factor-erythroid 2 p45-related factor 2 (Nrf2) is one of the most effective cytoprotective controller against OS. Modulation of Nrf2 pathway constitutes a remarkable strategy in the antineoplastic treatments. A big number of Nrf2-antioxidant response element activators have been screened for use as chemo-preventive drugs in OS associated diseases like cancer even though activation of Nrf2 happens in a variety of cancers. Research proved that hyperactivation of the Nrf2 pathway produces a situation that helps the survival of normal as well as malignant cells, protecting them against OS, anticancer drugs, and radiotherapy. In this review, the modulation of the Nrf2 pathway, anticancer activity and challenges associated with the development of an Nrf2-based anti-cancer treatment approaches are discussed.

Ubenimex Reverses MDR in Gastric Cancer Cells by Activating Caspase-3-Mediated Apoptosis and Suppressing the Expression of Membrane Transport Proteins

Gastric cancer (GC) is one of the most malignant tumors, accounting for 10% of deaths caused by all cancers. Chemotherapy is often necessary for treatment of GC; the FOLFOX regimen is extensively applied. However, multidrug resistance (MDR) of GC cells prevents wider application of this treatment. Ubenimex, an inhibitor of CD13, is used as an immune adjuvant to treat hematological malignancies. Here, we demonstrate that CD13 expression positively correlates with MDR development in GC cells. Moreover, Ubenimex reverses the MDR of SGC7901/X and MKN45/X cells and enhances their sensitivity to FOLFOX, in part by decreasing CD13 expression, which is accompanied by downregulation of Bcl-xl, Bcl-2, and survivin expression; increased expression of Bax; and activation of the caspase-3-mediated apoptotic cascade. In addition, Ubenimex downregulates expression of membrane transport proteins, such as P-gp and MRP1, by inhibiting phosphorylation in the PI3K/AKT/mTOR pathway to increase intracellular accumulations of 5-fluorouracil and oxaliplatin, a process for which downregulation of CD13 expression is essential. Therefore, the present results reveal a previously uncharacterized function of CD13 in promoting MDR development in GC cells and suggest that Ubenimex is a candidate for reversing the MDR of GC cells.

NRF2 through RPS6 Activation Is Related to Anti-HER2 Drug Resistance in HER2-Amplified Gastric Cancer

PURPOSE

Despite the clinical advantage of the combination of trastuzumab and platinum-based chemotherapy in HER2-amplified tumors, resistance will eventually develop. The identification of molecular mechanisms related to primary and acquired resistance is needed.

EXPERIMENTAL DESIGN

We generated lapatinib- and trastuzumab-resistant clones deriving from two different HER2-amplified gastric cancer cell lines. Molecular changes such as protein expression and gene-expression profile were evaluated to detect alterations that could be related to resistance. Functional studies in vitro were corroborated in vivo. The translational relevance of our findings was verified in a patient cohort.

RESULTS

We found RPS6 activation and NRF2 to be related to anti-HER2 drug resistance. RPS6 or NRF2 inhibition with siRNA reduced viability and resistance to anti-HER2 drugs. In knockdown cells for RPS6, a decrease of NRF2 expression was demonstrated, suggesting a potential link between these two proteins. The use of a PI3K/TORC1/TORC2 inhibitor, tested in vitro and in vivo, inhibited pRPS6 and NRF2 expression and caused cell and tumor growth reduction, in anti-HER2-resistant models. In a cohort of HER2-amplified patients treated with trastuzumab and chemotherapy, a high level of NRF2 at baseline corresponds with worse progression-free survival.

CONCLUSIONS

NRF2 through the PI3K/AKT/mTOR/RPS6 pathway could be a potential effector of resistance to anti-HER2 drugs in our models. RPS6 inhibition decreases NRF2 expression and restores sensitivity in HER2-amplified gastric cancer in vitro and in vivo. High NRF2 expression in gastric cancer patients predicts resistance to treatment. RPS6 and NRF2 inhibition could prevent resistance to anti-HER2 drugs.

AKR1B10 expression predicts response of gastric cancer to neoadjuvant chemotherapy

Effective methods for predicting tumor response to preoperative chemotherapy are required. Aldo-ketoreductase family 1 member B10 (AKR1B10) is predominantly expressed in the gastrointestinal tract and serves an important function in cancer development and progression. The present study investigated whether AKR1B10 expression may predict the therapeutic response of locally advanced gastric cancer. A total of 53 patients with gastric cancer underwent neoadjuvant chemotherapy followed by surgery between January 2006 and December 2015. The protein expression level of AKR1B10 was determined in paraffin-embedded biopsy specimens using immunohistochemistry. Western blotting confirmed that the AKR1B10 protein is primarily localized to the cytoplasm. χ² and Fisher's exact tests were used to determine the association of AKR1B10 with a number of clinic opathological features. Univariate and multivariate analyses were used to identify the prognostic factors. Survival rates were compared using Kaplan-Meier curves with a log-rank test. The positive rate of AKR1B10 protein expression was 58.5%, whereas 41.5% samples exhibited negative expression. The frequency of AKR1B10-positive gastric cancer samples was increased in patients with lymph node metastasis and decreased in those exhibiting tumor regression. The 5-years overall survival rate for the AKR1B10-positive group was significantly poorer than that for the AKR1B10-negative group. AKR1B10 expression was associated with lymph node metastasis and a poorer prognosis, along with a poor response to neoadjuvant chemotherapy suggesting that AKR1B10 may be a potential predictor for the therapeutic response of locally-advanced gastric cancer.

Potential Strategies Overcoming the Temozolomide Resistance for Glioblastoma

Glioblastoma (GBM) is a highly malignant type of primary brain tumor with a high mortality rate. Although the current standard therapy consists of surgery followed by radiation and temozolomide (TMZ), chemotherapy can extend patient's post-operative survival but most cases eventually demonstrate resistance to TMZ. O6-methylguanine-DNA methyltransferase (MGMT) repairs the main cytotoxic lesion, as O6-methylguanine, generated by TMZ, can be the main mechanism of the drug resistance. In addition, mismatch repair and BER also contribute to TMZ resistance. TMZ treatment can induce self-protective autophagy, a mechanism by which tumor cells resist TMZ treatment. Emerging evidence also demonstrated that a small population of cells expressing stem cell markers, also identified as GBM stem cells (GSCs), contributes to drug resistance and tumor recurrence owing to their ability for self-renewal and invasion into neighboring tissue. Some molecules maintain stem cell properties. Other molecules or signaling pathways regulate stemness and influence MGMT activity, making these GCSs attractive therapeutic targets. Treatments targeting these molecules and pathways result in suppression of GSCs stemness and, in highly resistant cases, a decrease in MGMT activity. Recently, some novel therapeutic strategies, targeted molecules, immunotherapies, and microRNAs have provided new potential treatments for highly resistant GBM cases. In this review, we summarize the current knowledge of different resistance mechanisms, novel strategies for enhancing the effect of TMZ, and emerging therapeutic approaches to eliminate GSCs, all with the aim to produce a successful GBM treatment and discuss future directions for basic and clinical research to achieve this end.

Gene Expression Subtype Predicts Nodal Metastasis and Survival in Human Papillomavirus-Negative Head and Neck Cancer

OBJECTIVES/HYPOTHESIS

Gene expression analyses of head and neck cancer have revealed four molecular subtypes: basal (BA), mesenchymal (MS), atypical (AT), and classical (CL). We evaluate whether gene expression subtypes in oral cavity squamous cell carcinoma (OCSCC) and laryngeal squamous cell carcinoma (LSCC) can be used to predict nodal metastasis and prognosticate survival.

STUDY DESIGN

Retrospective cohort study and genomic analysis.

METHODS

OCSCC and LSCC cases were identified from the The Cancer Genome Atlas (TCGA) head and neck cancer cohort. RNA-seq by expected maximization (RSEM) was used to quantify gene expression levels from TCGA RNA-seq data and to assign each case to one of four subtypes. Descriptive statistics were used to describe patient, disease, and treatment characteristics in each subtype. Cox regression and Kaplan-Meier analyses were used to determine associations with survival.

RESULTS

OCSCC cases were comprised primarily of the MS and BA subtypes, whereas LSCC was comprised primarily of CL and AT subtypes. In OCSCC, the MS subtype was significantly associated with higher risk of nodal metastasis. In a subset analysis of clinically T1-2N0M0 OCSCC, we demonstrate that the MS subtype was predictive of occult nodal metastasis (relative risk = 3.38, 95% confidence interval [CI]: 1.08-10.69). In LSCC, the CL subtype was associated with significantly worse overall survival (hazard ratio = 4.32, 95% CI: 1.77-10.54, P = .001).

CONCLUSIONS

Gene expression analysis reveals potential novel markers of nodal metastasis and survival in human papillomavirus-negative head and neck cancer. Future studies will continue to refine and validate these markers, with the goal of providing molecular risk assessments that guide therapy and improve patient outcomes.

LEVEL OF EVIDENCE

2b Laryngoscope, 129:154-161, 2019.

Expression of Keap1 and Nrf2 in diffuse large B-cell lymphoma and its clinical significance

The present study investigated the expression and clinical significance of kelch-like ECH-associated protein 1 (Keap1) and nuclear factor erythroid-2-related factor-2 (Nrf2) expression in diffuse large B-cell lymphoma (DLBCL). These proteins were detected by immunohistochemistry in 39 DLBCL cases and 17 cases of reactive lymph node hyperplasia, and their association with the clinicopathological features of DLBCL patients was analyzed. In DLBCL, the percentage of cells with positive staining for Keap1 and Nrf2 was 46.2 and 35.9%, respectively, which was significantly higher than that in reactive lymph node hyperplasia (17.7 and 5.9%, respectively). There was no correlation between Keap1 and Nrf2 expression according to a Spearman rank correlation analysis (r=0.272; P>0.05). Keap1 and Nrf2 expression was associated with the international prognostic index and Ann-Arbor clinical stage (P<0.05), and Keap1 and Nrf2 expression was higher in DLBCL patients with stage III–IV (68.4 and 52.6%, respectively) compared with in those with stage I–II (25.0 and 20.0%, respectively). The aberrant expression of Keap1 and Nrf2 in DLBCL suggests that these factors may have crucial roles in the development and progression of the disease, and may therefore be used as prognostic indicators.

Clinically significant association of elevated expression of nuclear factor E2-related factor 2 expression with higher glucose uptake and progression of upper urinary tract cancer

BACKGROUND

There is growing evidence that the transcription factor nuclear factor E2-related factor 2 (Nrf2) is the major participant in regulating antioxidants and pathways for detoxifying reactive oxygen species (ROS), as well as having a vital role in tumor proliferation, invasion, and chemoresistance. It was also recently reported that Nrf2 supports cell proliferation by promoting metabolic activity. Thus, Nrf2 is involved in progression of cancer. Upper urinary tract urothelial carcinoma (UTUC) is a biologically aggressive tumor with high rates of recurrence and progression, resulting in a poor prognosis. However, the role of Nrf2 in UTUC is largely unknown.

METHODS

In order to study the role of Nrf2 in UTUC from the metabolic perspective, we retrospectively assessed Nrf2 expression in the surgical specimen and the preoperative maximum standard glucose uptake (SUVmax) on [¹⁸F]fluorodeoxy-glucose positron emission tomography (¹⁸F-FDG-PET) of 107 patients with UTUC who underwent radical nephroureterectomy.

RESULTS

Increased expression of Nrf2 in the primary lesion was correlated with less differentiated histology, local invasion, and lymph node metastasis, and was also an independent indicator of shorter overall survival according to multivariate analysis. Furthermore, increased expression of Nrf2 was associated with higher preoperative SUVmax by the primary tumor on ¹⁸F-FDG-PET, while Nrf2 expression and SUVmax were also significantly correlated in the metastatic lymph nodes. Among the 18 patients with lymph node metastasis at nephroureterectomy who underwent retroperitoneal lymph node dissection and received adjuvant chemotherapy, the patients with higher Nrf2 expression in the primary tumor had worse recurrence-free survival.

CONCLUSIONS

These results suggest that constitutive activation of Nrf2 might be linked with tumor aerobic glycolysis and progression of UTUC, indicating that Nrf2 signaling in the tumor microenvironment promotes progression of UTUC.

Dual-negative expression of Nrf2 and NQO1 predicts superior outcomes in patients with non-small cell lung cancer

Functional studies in non-small cell lung cancer (NSCLC) patients revealed that hyperactivation of the NF-E2-related factor 2 (Nrf2) pathway facilitates tumor growth. We examined the usefulness of Nrf2 and NQO1 as indicators of prognosis in NSCLC. Tumor and adjacent non-tumor tissue samples were collected from 215 NSCLC patients who had tumor resections between 2006 and 2011. Immunohistochemistry was performed to detect Nrf2 or NQO1 expression. The correlation between Nrf2 or NQO1 expression and survival outcomes was evaluated using the Kaplan-Meier method and Cox proportional hazards regression model. Levels of Nrf2 and NQO1 were elevated in tumor tissues. In particular, Nrf2 was elevated in nearly all tumor cells. NQO1 expression positively correlated with Nrf2 expression (P = 0.039). Nrf2 expression positively correlated with lymph node metastasis (P = 0.001) and negatively correlated with tumor differentiation (P = 0.032). As compared with either Nrf2 or NQO1 alone, dual-negative expression of Nrf2 and NQO1 was more predictive of superior overall survival (P = 0.020) and disease free survival (P = 0.037). Subgroup analyses showed that females, nonsmokers, and patients with advanced-stage NSCLC were suitable populations in which to evaluate prognosis based on Nrf2 and NQO1 co-expression. These results indicate that dual-negative expression of Nrf2 and NQO1 is predictive of a better prognosis in NSCLC patients.

NRF2 addiction in cancer cells

The Kelch‐like ECH‐associated protein 1/nuclear factor erythroid‐derived 2‐like 2 (KEAP1‐NRF2) system is a pivotal defense mechanism against oxidative and electrophilic stress. Although transient NRF2 activation in response to stress is beneficial for health, persistent NRF2 activation in cancer cells has deleterious effects on cancer‐bearing hosts by conferring therapeutic resistance and aggressive tumorigenic activity on cancer cells. Because NRF2 increases the antioxidant and detoxification capability of cancer cells, persistently high levels of NRF2 activity enhance therapeutic resistance of cancer cells. NRF2 also drives metabolic reprogramming to establish cellular metabolic processes that are advantageous for cell proliferation in cooperation with other oncogenic pathways. As a result of these advantages, cancer cells with persistent activation of NRF2 often develop “NRF2 addiction” and show malignant phenotypes leading to poor prognoses in cancer patients. Inhibition of NRF2 is a promising therapeutic approach for NRF2‐addicted cancers and NRF2 inhibitors are being actively developed. However, giving systemic NRF2 inhibitors might have undesirable effects on cancer‐bearing hosts, considering the central roles of NRF2 in cytoprotection. To avoid these side‐effects, new therapeutic targets besides NRF2 for NRF2‐addicted cancers have been actively explored. This review introduces recent studies describing the development and characterization of NRF2‐addicted cancers, as well as their potential therapeutic targets. Expected advances in diagnostic and therapeutic interventions for NRF2‐addicted cancers are also discussed.

Nrf2 overexpression is associated with P-glycoprotein upregulation in gastric cancer

The efficacy of chemotherapeutic agents remains very poor in gastric cancer (GC) patients due to the development of multidrug resistance (MDR) phenotype. The nuclear factor erythroid 2-related factor 2 (Nrf2), is a pivotal transcriptional factor that regulates phase II detoxifying enzymes, antioxidants and efflux transporters including P-glycoprotein (P-gp). The aim of this study was to investigate the association of Nrf2 and P-gp and their correlations with clinicopathological criteria in GC patients.Nrf2 and MDR1/P-gp expressions in both mRNA and protein levels were examined by real-time PCR and immunohistochemical staining (IHC) respectively, in endoscopic biopsy samples from60 GC patients compared with those expressions in non-GC individuals. Our results from IHC examinations revealed that Nrf2 expression in GC patients (46.7%) is markedly higher than that in non-GC individuals (11.7%) (p<0.001, Mann-Whitney test) which was confirmed by real-time PCR in mRNA levels. Induction of P-gp as a drug efflux pump, was associated with Nrf2 overexpression in these samples (r=0.55, p<0.001). There was also a strong correlation between Nrf2 overexpression and tumor size, histological grade, lymph node and distant metastasis while P-gp upregulation was shown to be associated only with the histological grade and tumor size (Chi-square, all p<0.05). Our results suggest that therapeutic inhibition of Nrf2 expression can improve the efficacy of chemotherapeutic agents for GC patients by down regulation of P-gp expression.

The prognostic value of NRF2 in solid tumor patients: a meta-analysis

Nuclear factor E2-related factor 2 (NRF2), a transcription factor, is known as a potential therapeutic target of solid tumor for that it is a master regulator of the injury and inflammation response, including controlling antioxidant cell progress. Recent studies showed that NRF2 played significant roles in tumorigenesis and tumor progression, however no association and relationship between NRF2 expression and different clinical manifestation of solid tumor had been accurately evaluated. The present meta-analysis picked up 17 suitable articles from EMBASE, PubMed, and ISI Web of Science databases, including 2238 patients. Combined with results of hazard ratios (HRs) and 95% confidence intervals (CIs), we concluded that a higher expression of NRF2 would have worse impact on overall survival (HR = 2.29, 95% CI 1.80–2.91, P < 0.05) and disease-free survival (HR = 2.34, 95% CI 1.36–4.00, P < 0.05) by a random-effect model. Moreover, further results were positively correlated to the clinical diagnosis, curative effect observation and prognosis, including tumor differentiation, lymph node metastasis, distant metastasis and clinical stage. Consequently, our data shown that NRF2 is a potential poor prognostic factor in a variety of solid tumors.

Clinical implication of Keap1 and phosphorylated Nrf2 expression in hepatocellular carcinoma

In this paper, variation tendency of phosphorylated Nrf2, as the activated form of native Nrf2, was studied in 107 primary hepatocellular carcinoma (HCC) specimens treated by curative hepatectomy. Moreover, the coexpression of oxidative stress markers Keap1 and pNrf2, and their association with pathological features were also evaluated based on those specimens. The results showed that preserved cytoplasmic Keap1 expression of cancer cells was observed in 59 HCCs, while reduced Keap1 expression was determined in remaining 48 ones. With regarding to nuclear pNrf2 expression, 75 HCCs were defined as high and the other 32 ones as low. There was a significant association between Keap1 and pNrf2 expression in HCCs. Higher pNrf2 expression was observed, at a more substantial proportion, in those specimens with reduced Keap1 expression, compared to those with preserved Keap1 expression. The subset with higher pNrf2 and reduced Keap1 expression was defined as pNrf2⁺ Keap1⁻. According to the analysis of prognosis, this subset was significantly associated with poor 5‐year overall survival and worse disease‐free survival in HCCs, indicating that pNrf2 and Keap1 were two‐functional biomolecules, not only the oxidative stress markers but also biomarkers for prognosis of HCCs.

Emerging role of NRF2 in chemoresistance by regulating drug-metabolizing enzymes and efflux transporters

Chemoresistance is a disturbing barrier in cancer therapy, which always results in limited therapeutic options and unfavorable prognosis. Nuclear factor E2-related factor 2 (NRF2) controls the expression of genes encoding cytoprotective enzymes and transporters that protect against oxidative stress and electrophilic injury to maintain intrinsic redox homeostasis. However, recent studies have demonstrated that aberrant activation of NRF2 due to genetic and/or epigenetic mutations in tumor contributes to the high expression of phase I and phase II drug-metabolizing enzymes, phase III transporters, and other cytoprotective proteins, which leads to the decreased therapeutic efficacy of anticancer drugs through biotransformation or extrusion during chemotherapy. Therefore, a better understanding of the role of NRF2 in regulation of these enzymes and transporters in tumors is necessary to find new strategies that improve chemotherapeutic efficacy. In this review, we summarized the recent findings about the chemoresistance-promoting role of NRF2, NRF2-regulated phase I and phase II drug-metabolizing enzymes, phase III drug efflux transporters, and other cytoprotective genes. Most importantly, the potential of NRF2 was proposed to counteract drug resistance in cancer treatment.

Myeloid-Derived Suppressor Cell Survival and Function Are Regulated by the Transcription Factor Nrf2

Tumor-induced myeloid-derived suppressor cells (MDSC) contribute to immune suppression in tumor-bearing individuals and are a major obstacle to effective immunotherapy. Reactive oxygen species (ROS) are one of the mechanisms used by MDSC to suppress T cell activation. Although ROS are toxic to most cells, MDSC survive despite their elevated content and release of ROS. NF erythroid 2-related factor 2 (Nrf2) is a transcription factor that regulates a battery of genes that attenuate oxidative stress. Therefore, we hypothesized that MDSC resistance to ROS may be regulated by Nrf2. To test this hypothesis, we used Nrf2(+/+)and Nrf2(-/-)BALB/c and C57BL/6 mice bearing 4T1 mammary carcinoma and MC38 colon carcinoma, respectively. Nrf2 enhanced MDSC suppressive activity by increasing MDSC production of H2O2, and it increased the quantity of tumor-infiltrating MDSC by reducing their oxidative stress and rate of apoptosis. Nrf2 did not affect circulating levels of MDSC in tumor-bearing mice because the decreased apoptotic rate of tumor-infiltrating MDSC was balanced by a decreased rate of differentiation from bone marrow progenitor cells. These results demonstrate that Nrf2 regulates the generation, survival, and suppressive potency of MDSC, and that a feedback homeostatic mechanism maintains a steady-state level of circulating MDSC in tumor-bearing individuals.

Functional Role of NRF2 in Cervical Carcinogenesis

Nuclear factor erythroid-2-related factor 2 (NFE2L2) is a transcription factor associated with resistance to chemotherapy and increased tumor growth. NRF2 is repressed by the inhibitor Keap1. The Keap1-NRF2 pathway is dysfunctional in multiple tumor types. Among Uighur women, the incidence of cervical squamous cell carcinoma (CSCC) and cervical intraepithelial neoplasia (CIN) was associated with elevated nuclear expression of NRF2 and decreased cytoplasmic expression of Keap1. Up-regulation of nuclear NRF2 was significantly associated with reduced cytoplasmic Keap1 expression. NRF2 positivity and Keap1 negativity were frequently associated with more advanced tumors (i.e., higher histological grade, lymph node involvement, and higher tumor stages) (p<0.05 for all). Methylated CpG islands in the Keap1 gene promoter in cervical cancer tissue were identified using MassARRAY. Moreover, promoter hypermethylation of this gene was significantly associated with decreased protein expression and increased nuclear NRF2 expression in cervical cancer tissues. Overexpression and knockdown of NRF2 in CSCC cell lines showed that NRF2 promotes proliferation, inhibits apoptosis, and enhances migration and invasion. These studies support the concept that epigenetic changes regulate expression of Keap1 in cervical cancer tissues. The association of NRF2 expression with aggressive tumor behavior suggests that NRF2 may be a marker of poor prognosis in patients with cervical cancer.

Correlation of NQO1 and Nrf2 in Female Genital Tract Cancer and Their Precancerous Lesions (Cervix, Endometrium and Ovary)

Background

NAD (P) H/quinone oxidoreductase 1 (NQO1) is a metabolizing enzyme that detoxifies chemical stressors and antioxidants. Nuclear factor erythroid 2-related factor 2 (NrF2) is an important transcriptional activator involved in the cellular defense mechanisms against oxidative stress.

Methods

The immunohistochemical expression of NQO1 and Nrf2 in 80 cervical, 80 endometrial and 100 ovarian specimens with different lesions was studied. Then we study the relation of both NQO1 and Nrf2 expression and clinicopathological features of carcinoma cases.

Results

Immunohistochemical stain showed that NQO1 and Nrf2 were highly expressed in carcinoma compared with normal and precancerous lesions. Significant positive correlations were found between the mean expression of NQO1 and Nrf2 in different lesions. Moreover, there was significant correlation between the high level of NQO1 and Nrf2 expression and high tumor grade in cervical and endometrial carcinoma cases. Nrf2 expression was significant with advanced stage in endometrial and ovarian carcinomas.

Conclusions

NQO1 and Nrf2 might be new biomarkers for early diagnosis and prognostic evaluation as well as being targets for therapy in patients with tumors in female genital tract.