SNP (-617C>A) in ARE-like loci of the NRF2 gene: a new biomarker for prognosis of lung adenocarcinoma in Japanese non-smoking women

Genetic Variants in Oxidative Stress-Related Genes and Their Impact on Prognosis and Treatment Response in Chronic Myeloid Leukemia Patients

Chronic myeloid leukemia (CML) is a clonal myeloproliferative neoplasia characterized by the BCR::ABL1 fusion gene, which codifies the BCR-ABL protein with increased tyrosine kinase activity. Despite the clinical results for the outstanding tyrosine kinase inhibitors (TKIs), drug resistance is a problem in CML management. Genetic variants that alter redox homeostasis by changing antioxidant enzyme expression or activity may influence patient responses and could enhance patient stratification. We aimed to assess the association of SOD2, CAT GPX1, NRF2, and KEAP1 genetic variants with TKI response and disease prognosis. For this purpose, we genotyped the variants rs4880 (SOD2), rs1050450 (GPX1), rs1001179 (CAT), rs6721961, rs4893819, rs35652124, rs6706649, rs13001694 (NFE2L2), and rs113540846 (KEAP1) via PCR in 187 CML patients. Our results show that variants in genes related to oxidative stress influence the development and degree of TKI resistance (allele G and GG genotypes of GPX1 and CT genotype of NFE2L2 rs4893819), the appearance of mutations in the BCR::ABL1 gene (AG genotype of NFE2L2 rs13001694 and genetic profile GGCTTCCCGG of the NFE2L2/KEAP1 axis), disease evolution (AG genotype of SOD2 and CT genotype of NFE2L2 rs4893819), and overall survival (CC genotype of CAT and GG genotype of NFE2L2 rs13001694) of CML patients. Our study found that variants in oxidative stress-related genes impact treatment response and outcomes in CML.

Prognostic Significance of Methyl-CpG Binding Domain4 Polymorphism rs140693 and Clinical Characteristics in Chinese Lung Cancer Patients

Lung cancer remains the leading cause of death among cancer patients, and the five-year survival rate is less than 25%. However, Methyl-CpG Binding Domain (MBD)4 polymorphism rs140693 predicts the prognosis of lung cancer patients still needs further verification. Primary lung cancer patients (n = 839) were collected from two hospitals, genomic DNA was extracted from blood, and genotyping was performed using SNPcan technology. Kaplan-Meier technique and multivariate Cox proportional hazards model were used to analyze the prognosis association between MBD4 and clinical characteristics. Significantly conferred a poorer prognosis was associated with the CT genotype (CT vs. CC; adjusted hazard ratio [HR] = 1.21, 95% CI: 1.03-1.43, p = 0.023) and dominant CT + TT genotype (CT + TT vs. CC; HR = 1.19, 95% CI: 1.02-1.39, p = 0.029) of MBD4 polymorphism rs140693 for all lung cancer patients, compared with the CC genotype. Stratified analysis showed that polymorphism rs140693 CT and dominant CT + TT genotype conferred a significantly poorer prognosis in female and lung adenocarcinoma (ADC) cancer patients, compared with the CC genotype. Non-small cell lung cancer (NSCLC) patients with the CT genotype had a poorer prognosis than those with the CC genotype. Additionally, the allele T of small cell lung cancer (SCLC) patients compared with the allele C was associated with a poor prognosis, and the CT and recessive TT genotype of SCLC patients conferred a significantly poor prognosis. The MBD4 polymorphism rs140693 is a significant prognostic genetic marker for predicting the prognosis of lung cancer patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43657-024-00171-z.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Decreased DNA repair capacity caused by exposure to metal mixtures is modulated by the PARP1 rs1136410 variant in newborns from a polluted metropolitan area

BACKGROUND

DNA damage caused by exposure to metal mixtures and the potential modulating role of genes involved in DNA repair and the antioxidant response have not been evaluated in newborns.

AIM

The aim was to evaluate the association between prenatal exposure to metal mixtures and DNA repair capacity (DRC) in newborns from the Metropolitan Area of Mexico City (MAMC), a heavily polluted area, and the impact of variants in genes involved in DNA repair and the antioxidant response on this association.

METHODS

We analyzed cord blood samples obtained at delivery from 125 healthy newborns from the MAMC. Twenty-four elements were determined by inductively coupled plasma mass spectrometry (ICP‒MS), but only 12 (Cu, I, Se, Zn, As, Ba, Cs, Mn, Sb, Sr, Pb, and Ti) were quantified in most samples. DRC was assessed by the challenge-comet assay, and OGG1, PARP1, and NFE2L2 genotyping was performed with TaqMan probes. Metal mixtures were identified and analyzed using principal component analysis (PCA) and weighted quantile sum (WQS) regression. Independent adjusted linear regression models were used to evaluate the associations.

RESULTS

A null DRC was observed in 46% of newborns. The metals with the highest concentrations were Mn, Sr, Ti, and Pb. Essential elements showed normal levels. Only the mixture characterized by increased As, Cs, Cu, Se, and Zn levels was inversely associated with DRC. As was the principal contributor (37.8%) in the negative direction in the DRC followed by Ba and Sb, according to the WQS regression. Newborns carrying of the derived (G) allele of the PARP1 rs1136410 variant showed decreased DRC by exposure to some potentially toxic metals (PTMs) (As, Cs, and Ba).

CONCLUSION

Prenatal exposure to metal mixtures negatively affected DRC in newborns, and the PARP1 rs1136410 variant had a modulating role in this association.

Molecular basis of sex differences in cancer: Perspective from Asia

Cancer is a leading cause of mortality and morbidity globally. Sex differences in cancer are evident in death rates and treatment responses in several cancers. Asian patients have unique cancer epidemiology influenced by their genetic ancestry and sociocultural factors in the region. In this review, we show molecular associations that potentially mediate sex disparities observed in cancer in Asian populations. Differences in sex characteristics are evident at the cytogenetic, genetic, and epigenetic levels mediating processes that include cell cycle, oncogenesis, and metastasis. Larger clinical and in vitro studies that explore mechanisms can confirm the associations of these molecular markers. In-depth studies of these markers can reveal their importance as diagnostics, prognostics, and therapeutic efficacy markers. Sex differences should be considered in designing novel cancer therapeutics in this era of precision medicine.

Antioxidants-related nuclear factor erythroid 2-related factor 2 gene variants associated with HBV-related liver disease

BACKGROUND

Accumulating evidence demonstrated that nuclear factor erythroid 2-related factor 2 (NRF2) expression plays a crucial role in the proliferation, invasion and metastasis of hepatocellular carcinoma (HCC). However, research on the effect of NRF2 genetic polymorphism on the development of chronic hepatitis B (CHB), HBV-related liver cirrhosis (LC) and HCC is still missing.

METHODS

A total of 673 individuals were included in the study and classified into four groups: 110 CHB cases, 86 LC cases, 260 HCC cases, and 217 healthy controls. ​The polymerase chain reaction-restriction fragment length polymorphism and DNA sequencing method were used to detect rs6721961 and rs6726395 polymorphisms.

RESULTS

Patients carrying the T allele in rs6721961 were at a higher risk of HCC than individuals with the G allele compared to CHB patients (OR = 1.561, 95%CI: 1.003-2.430, P = 0.048). The statistically significant differences were also found in the rs6721961 GT genotype (OR = 2.298, 95% CI: 1.282-4.119, P = 0.005) and dominant model (OR = 2.039, 95% CI: 1.184-0.510, P = 0.010). Subgroup analysis also detected a significant association between the rs6721961 T allele and the development of HCC in older subjects (≥ 50 years) (OR = 2.148, 95% CI: 1.208-3.818, P = 0.009). Statistical analysis results indicated that subjects carrying haplotype G-A had a lower risk of HCC (OR = 0.700, 95% CI: 0.508-0.965, P = 0.028).

CONCLUSIONS

For the first time, our findings provide evidence that the NRF2 gene rs6721961 variation is a potential genetic marker of susceptibility to HCC.

Contribution of Genetic Polymorphisms in Human Health

Human health is influenced by various factors; these include genetic inheritance, behavioral lifestyle, socioeconomic and environmental conditions, and public access to care and therapies in case of illness, with the support of the national health system. All these factors represent the starting point for the prevention and promotion of a healthy lifestyle. However, it is not yet clear to what extent these factors may actually affect the health of an entire population. The exposures to environmental and occupational factors are several, most of which might be poorly known, contributing to influencing individual health. Personal habits, including diet, smoking, alcohol, and drug consumption, together with unhealthy behaviors, may inevitably lead people to the development of chronic diseases, contributing to increasing aging and decreasing life expectancy. In this article, we highlight the role of susceptibility biomarkers, i.e., the genetic polymorphisms of individuals of different ethnicities, with particular attention to the risk factors in the response to specific exposures of Europeans. Moreover, we discuss the role of precision medicine which is representing a new way of treating and preventing diseases, taking into account the genetic variability of the individual with each own clinical history and lifestyle.

Nrf2 rs6721961 and Oxidative Stress in Preeclampsia: Association with the Risk of Preeclampsia and Early-Onset Preeclampsia

Preeclampsia as a multifactor hypertensive disorder of pregnancy is associated with enhanced placental oxidative stress. The Keap1-Nrf2 pathway protects cells against oxidative stress. We examined the possible association between the Nrf2 variants in relation to oxidative stress parameters with the risk of preeclampsia. We studied 150 preeclampsia women and 150 women with a normal pregnancy to find the frequency of Nrf2 rs6721961 genotypes using the PCR-RFLP method. Also, an association between the Nrf2 genotypes with the levels of malondialdehyde (MDA) and total antioxidant capacity (TAC) was analyzed. Significantly lower TAC and higher MDA levels were found in preeclampsia patients compared to controls (P<0.0001). For the first time, we report an association between the Nrf2 rs6721961 polymorphism and preeclampsia risk. The present study indicated that the GT genotype and the T allele of the Nrf2 rs6721961 increased the risk of preeclampsia by 2.81 and 2.39 times, respectively. Also, the Nrf2 TT genotype was associated with a 3.9-fold increased risk of early-onset preeclampsia. We detected a positive association between the levels of body mass index, MDA, and the Nrf2 polymorphism with the risk of preeclampsia and a negative correlation between the level of TAC with the preeclampsia risk. Also, an association between the rs6721961 TT genotype with higher serum MDA levels was found. Our study suggests oxidative stress is involved in the pathogenesis of preeclampsia and the Nrf2 rs6721961 polymorphism through alteration in the levels of oxidative stress parameters might increase the risk of preeclampsia and early-onset preeclampsia.

Potential of NRF2 Pathway in Preventing Developmental and Reproductive Toxicity of Fine Particles

Air pollution is associated with significant adverse health effects. Recent studies support the idea that inhalation of fine particles can instigate extrapulmonary effects on the cardiovascular system through several pathways. The systemic transfer of ultrafine particles (UFPs) or soluble particle components (organic compounds and metals) is of particular concern. An integral role of reactive oxygen species (ROS)-dependent pathways has been suggested in systemic inflammatory responses and vascular dysfunction at the molecular level. Accumulating lines of evidence suggest that fine particles affect fetal development, giving rise to low birth weight and a reduction in fetal growth, and also affect the immune, cardiovascular, and central nervous systems. Oxidative stress plays an important role in fine particles toxicity; pre-treatment with antioxidants partially suppresses the developmental toxicity of fine particles. On the other hand, Nuclear factor erythroid-derived 2-like 2 (Nfe2l2), also known as NRF2, is a transcription factor essential for inducible and/or constitutive expression of phase II and antioxidant enzymes. Studies using Nrf2-knockout mice revealed that NRF2 dysfunction is intimately involved in the pathogenesis of various human diseases. Multiple single nucleotide polymorphisms (SNPs) have been detected in human NRF2 locus. An NRF2 gene SNP (−617C > A; rs6721961), located in the upstream promoter region, affects the transcriptional level of NRF2 and thereby the protein level and downstream gene expression. It has been reported that the SNP-617 is associated with various diseases. The onset and exacerbation of the diseases are regulated by genetic predisposition and environmental factors; some people live in the air-polluted environment but are not affected and remain healthy, suggesting the presence of individual differences in the susceptibility to air pollutants. NRF2 polymorphisms may also be associated with the fetal effects of fine particles exposure. Screening high-risk pregnant women genetically susceptible to oxidative stress and prevention by antioxidant interventions to protect fetal development in air-polluted areas should be considered. This article reviews the recent advances in our understanding of the fetal health effects of fine particles and describes potential chemoprevention via the NRF2 pathway to prevent the developmental and reproductive toxicity of fine particles.

Functional Polymorphism in the NFE2L2 Gene Associated With Tuberculosis Susceptibility

Background

Nuclear transcription factor erythroid 2 p45-related factor 2 (Nrf2), encoded by NFE2L2, functions as a key transcription factor and regulates expression of antioxidant genes. Our study aimed to investigate the association of single nucleotide polymorphisms of NFE2L2 with tuberculosis (TB) and latent tuberculosis infection (LTBI) and the underlying causal mechanisms.

Methods

1950 unrelated Chinese Han participants were included in our two independent study groups. Five tag polymorphisms were selected and genotyped. The functional effects of the rs13005431 polymorphism were confirmed by dual-luciferase reporter assays and mRNA level comparisons.

Results

Rs13005431_C and rs2364723_G were associated with increased TB susceptibility (P = 0.010 and P = 0.041) after adjustment for confounding factors. rs6726395_A was associated with increased risk of active TB (P=0.035) in a comparison with the LTBI group. The frequency of haplotype rs1049751- rs13005431 AC was higher in the TB group (P =0.013), while frequency of haplotype AT was higher in the healthy control group (P =0.025). The luciferase activity of a plasmid with the rs13005431C-promoter was significantly lower than that of the rs13005431T-promoter. In addition, neutrophils with the CC/TC genotypes which were activated by GM-CSF showed a decreased level of NFE2L2 mRNA when compared with the rs13005431 TT genotype.

Conclusions

Our study suggests that allele C of rs13005431 might increase the susceptibility to TB by down-regulating the transcriptional activity of NFE2L2.

The Association of Polymorphisms in Nrf2 and Genes Involved in Redox Homeostasis in the Development and Progression of Clear Cell Renal Cell Carcinoma

Deleterious effects of SNPs found in genes encoding transcriptional factors, as well as antioxidant and detoxification enzymes, are disputable; however, their functional significance seems to modify the risk for clear cell renal cell carcinoma (ccRCC) development and progression. We investigated the effect of specific Nrf2, SOD2, GPX1 gene variants and GSTP1ABCD haplotype on ccRCC risk and prognosis and evaluated the association between GSTP1 and regulatory (JNK1/2) and executor (caspase-3) apoptotic molecule expression in ccRCC tissue samples and the presence of GSTP1 : JNK1/2 protein : protein interactions. Genotyping was performed in 223 ccRCC patients and 336 matched controls by PCR-CTTP and qPCR. Protein expression was analyzed using immunoblot, while the existence of GSTP1 : JNK1 protein : protein interactions was investigated by immunoprecipitation experiments. An increased risk of ccRCC development was found among carriers of variant genotypes of both SOD2 rs4880 and GSTP1 rs1695 polymorphisms. Nrf2 rs6721961 genetic polymorphism in combination with both rs4880 and rs1695 showed higher ccRCC risk as well. Haplotype analysis revealed significant risk of ccRCC development in carriers of the GSTP1C haplotype. Furthermore, GSTP1 variant forms seem to affect the overall survival in ccRCC patients, and the proposed molecular mechanism underlying the GSTP1 prognostic role might be the presence of GSTP1 : JNK1/2 protein : protein interactions.

Association of single nucleotide polymorphisms in the NRF2 promoter with vascular stiffness with aging

Purpose

Pulse wave velocity (PWV), an indicator of vascular stiffness, increases with age and is increasingly recognized as an independent risk factor for cardiovascular disease (CVD). Although many mechanical and chemical factors underlie the stiffness of the elastic artery, genetic risk factors related to age-dependent increases in PWV in apparently healthy people are largely unknown. The transcription factor nuclear factor E2 (NF-E2)-related factor 2 (Nrf2), which is activated by unidirectional vascular pulsatile shear stress or oxidative stress, regulates vascular redox homeostasis. Previous reports have shown that a SNP in the NRF2 gene regulatory region (−617C>A; hereafter called SNP−617) affects NRF2 gene expression such that the minor A allele confers lower gene expression compared to the C allele, and it is associated with various diseases, including CVD. We aimed to investigate whether SNP−617 affects vascular stiffness with aging in apparently healthy people.

Methods

Analyzing wide-ranging data obtained from a public health survey performed in Japan, we evaluated whether SNP−617 affected brachial-ankle PWV (baPWV) in never-smoking healthy subjects (n = 642). We also evaluated the effects of SNP−617 on other cardiovascular and blood test measurements.

Results

We have shown that not only AA carriers (n = 55) but also CA carriers (n = 247) show arterial stiffness compared to CC carriers (n = 340). Furthermore, SNP−617 also affected blood pressure indexes such as systolic blood pressure and mean arterial pressure but not the ankle brachial pressure index, an indicator of atherosclerosis. Multivariate analysis showed that SNP−617 accelerates the incremental ratio of baPWV with age.

Conclusions

This study is the first to show that SNP−617 affects the age-dependent increase in vascular stiffness. Our results indicate that low NRF2 activity induces premature vascular aging and could be targeted for the prevention of cardiovascular diseases associated with aging.

Small molecular Nrf2 inhibitors as chemosensitizers for cancer therapy

The basic leucine zipper transcription factor Nrf2 is the primary regulator of cellular oxidative stress. Activation of Nrf2 is regarded as a potential preventive and therapeutic strategy. However, aberrant hyperactivation of Nrf2 is found in a variety of cancers and promotes cancer progression and metastasis. Moreover, constitutive activation of Nrf2 confers cancer cells resistance to chemo- and radio-therapy. Thus, inhibiting Nrf2 could be a new therapeutic strategy for cancer. With the aim of accelerating the discovery and development of novel Nrf2 inhibitors, we summarize the biological and pathological functions of Nrf2 in cancer. Furthermore, the recent studies of small molecular Nrf2 inhibitors and potential Nrf2 inhibitory mechanisms are also summarized in this review.

Rare and common genetic variations in the Keap1/Nrf2 antioxidant response pathway impact thyroglobulin gene expression and circulating levels, respectively

Nuclear factor, erythroid 2-like 2 (Nrf2) is a transcription factor that has been gaining attention in the field of pharmacology and especially in the chemoprevention of diseases such as cancer, metabolic and neurodegenerative diseases, etc. This is because natural compounds such as sulforaphane, which is found in broccoli sprout extracts, can activate Nrf2. The repertoire of the roles of Nrf2 is ever increasing; besides its traditional antioxidant and cytoprotective effects, Nrf2 can have other functions as a transcription factor. We have recently shown that Nrf2 directly regulates the expression of thyroglobulin (Tg), which is the most abundant thyroidal protein and the precursor of thyroid hormones. Two functional binding sites for Nrf2 (antioxidant response elements, AREs) were identified in the regulatory region of the TG gene. Interestingly, we then observed that one of these AREs harbors a rare single-nucleotide polymorphism (SNP). Also recently, we performed the first genome-wide association study (GWAS) for common SNPs that impact the circulating levels of Tg. Based on these investigations, we were triggered (i) to investigate whether common SNPs in the Nrf2 pathway correlate with circulating Tg levels; and (ii) to examine whether the rare SNP in one of the TG regulatory AREs may affect gene expression. To address the first question, we analyzed GWAS data from a general population and its two subpopulations, one with thyroid disease and/or abnormal thyroid function tests and the other without, in which circulating Tg levels had been measured. Statistically significant associations with Tg levels were observed in the genes encoding Nrf2 and Keap1, including, notably, a known functional SNP in the promoter of the gene encoding Nrf2. Regarding the rare SNP (rs778940395) in the proximal ARE of the TG enhancer, luciferase reporter gene expression studies in PCCL3 rat thyroid follicular cells showed that this SNP abrogated the basal and sulforaphane- or TSH-induced luciferase activity, behaving as a complete loss-of-function mutation. Thus, both rare and common genetic variation in the Keap1/Nrf2 pathway can impact TG expression and Tg circulating levels, respectively.

A Polymorphism rs6726395 in Nrf2 Contributes to the Development of Emphysema-Associated Age in Smokers Without COPD

INTRODUCTION

Several studies have reported that single nucleotide polymorphisms (SNPs) in the gene encoding NF-E2-related factor 2 (Nrf2) contribute to airflow limitations in smokers without COPD. Although small airway lesions and emphysema contribute cooperatively to airflow limitation, the relationship between Nrf2 SNPs and the development of emphysema in smokers without COPD is not well understood.

METHODS

Healthy subjects who underwent an annual health checkup with computed tomography (CT) of the chest at Osaka City University Hospital were prospectively recruited. The percentage of low-attenuation area (%LAA) on chest CT was quantified, and correlations between %LAA, Nrf2 SNP [rs6726395 (G/A)] genotypes, and clinical characteristics were examined.

RESULTS

A total of 245 subjects without COPD [non-/light-smoker: 153 (62.4%) and smoker: 92 (37.6%)] were enrolled. The %LAA in the upper lung field was higher than that in the lower lung field (p < 0.001). The %LAA in smokers was significantly higher than that in non-/light-smokers (p = 0.021). The %LAA showed significant but weak correlation with age in all subjects (r = 0.141, p = 0.028). Divided by genotype, the %LAA of the upper lung field was significantly correlated with age in smokers with genotype GG (wild type) (r = 0.333, p = 0.022), but was not significantly correlated with age in smokers with genotype AG/AA. These correlations were not observed in non-/light smokers.

CONCLUSION

A polymorphism rs6726395 in Nrf2 can contribute to the development of emphysema-associated aging in smokers. The Nrf2 SNP may be a predictive factor for smoking-induced emphysema, and genotyping of Nrf2 SNP may serve as biomarker for emphysema prevention.

Prognosis of hormone-dependent breast cancer seems to be influenced by KEAP1, NRF2 and GSTM1 genetic polymorphisms

Influence of Glutathione S-transferase Mu1 (GSTM1) has long been studied in breast cancer and GSTM1 null genotype was correlated with breast cancer risk. Nuclear factor-erythroid 2-related factor-2 (NRF2) is a transcription factor that forms a complex with Kelch-like ECH-associated protein-1 (KEAP1). Recent studies have demonstrated that expression of these proteins is deregulated in several malignancies. Thus, in the present study we aim to distinguish GSTM1 heterozygous from wild type genotype in breast cancer patients and evaluate the presence and clinical significance of NRF2 and KEAP1 polymorphisms, alone or in association, with breast cancer prognosis, in cases confirmed to have GSTM1-present genotype. Study population consisted in 52 patients with breast cancer. Genomic DNA was extracted, GSTM1 was genotyped through multiplex PCR and gene dose was evaluated through real-time PCR. All cases were sequenced, through Sanger sequencing, for specific regions of NRF2 and KEAP1. Genotyping and clinicopathological data were correlated and statistical analysis was performed. GSTM1 wild type was identified in 1 case and 26 cases were identified as heterozygous, these data were correlated with Human Epidermal growth factor Receptor 2 (HER2) status (p value = 0.017). We also verified that most cancers diagnosed at younger ages had the presence of KEAP1 and/or NRF2 polymorphisms. The association of GSTM1 heterozygous genotype with rs1048290 and rs35652124 seems to be associated with HER2⁺ (p < 0.05). Our results suggest that GSTM1 * 1/0 genotype and the cumulative presence of at least one allele mutated in KEAP1 and/or NRF2 polymorphisms might be associated with worse prognosis for breast cancer patients.

Emerging Therapeutic Targets in Oncologic Photodynamic Therapy

Background:

Reactive oxygen species sustain tumorigenesis and cancer progression through deregulated redox signalling which also sensitizes cancer cells to therapy. Photodynamic therapy (PDT) is a promising anti-cancer therapy based on a provoked singlet oxygen burst, exhibiting a better toxicological profile than chemo- and radiotherapy. Important gaps in the knowledge on underlining molecular mechanisms impede on its translation towards clinical applications.

Aims and Methods:

The main objective of this review is to critically analyse the knowledge lately gained on therapeutic targets related to redox and inflammatory networks underlining PDT and its outcome in terms of cell death and resistance to therapy. Emerging therapeutic targets and pharmaceutical tools will be documented based on the identified molecular background of PDT.

Results:

Cellular responses and molecular networks in cancer cells exposed to the PDT-triggered singlet oxygen burst and the associated stresses are analysed using a systems medicine approach, addressing both cell death and repair mechanisms. In the context of immunogenic cell death, therapeutic tools for boosting anti-tumor immunity will be outlined. Finally, the transcription factor NRF2, which is a major coordinator of cytoprotective responses, is presented as a promising pharmacologic target for developing co-therapies designed to increase PDT efficacy.

Conclusion:

There is an urgent need to perform in-depth molecular investigations in the field of PDT and to correlate them with clinical data through a systems medicine approach for highlighting the complex biological signature of PDT. This will definitely guide translation of PDT to clinic and the development of new therapeutic strategies aimed at improving PDT.

Targeting Cancer Stem Cell Redox Metabolism to Enhance Therapy Responses

Cancer has long been viewed as a disease of altered metabolism. Although it has long been recognized that the majority of cancer cells display increased dependence on glycolysis, the metabolism of "cancer stem-like cells" (CSCs) that drive tumor growth and metastasis is less well characterized. In this chapter, we review the current state of knowledge of CSC metabolism with an emphasis on the development of therapeutic strategies to exploit the metabolic vulnerabilities of these cells. We outline emerging evidence indicating distinct metabolic pathways active in the proliferative, epithelial- (E) and quiescent, mesenchymal-like (M) CSC states in triple negative breast cancer. These CSC states are characterized by their different redox potentials and divergent sensitivities to inhibitors of glycolysis and redox metabolism. We highlight the roles of two redox-regulated signaling pathways, hypoxia-inducible factor 1α and nuclear factor erythroid 2-related factor 2, in regulating CSC epithelial-mesenchymal plasticity during metabolic and/or oxidative stress, and discuss clinical strategies using combinations of pro-oxidant-based therapeutics simultaneously targeting E- and M-like CSCs. By specifically targeting CSCs of both states, these strategies have the potential to increase the therapeutic efficacy of traditional chemotherapy and radiation therapy.

Epigenetic modifications but not genetic polymorphisms regulate KEAP1 expression in colorectal cancer

Kelch-like ECH-associated protein 1 (KEAP1), as a negative regulator of nuclear factor erythroid 2 like 2 ( NRF2), plays a pivotal role in NRF2 signaling pathway and involves in tumorigenesis. Polymorphisms and methylation in gene promoter region may influence its expression and be related to cancer susceptibility. In this study, we examined the effect of the KEAP1-NRF2 interaction on the risk of colorectal cancer (CRC). The polymorphisms of NRF2 and KEAP1 were genotyped using the improved multiplex ligase detection reaction assay. KEAP1 promoter methylation and histone modification were analyzed using bisulfite genome sequencing and chromatin immunoprecipitation (ChIP) assay, respectively. The KEAP1 rs1048290 CC genotype and C allele were associated with increased risks of CRC (CC vs GG: odds ratio [OR] = 1.39; 95% confidence interval [CI], 1.08-1.78; CC vs GG/GC: OR = 1.29; 95% CI, 1.05-1.58; C vs G: OR = 1.18; 95% CI, 1.04-1.34). The rs1048290-rs11545829 GT haplotype was associated with a reduced risk of CRC. KEAP1-NRF2 interaction analysis revealed that the rs6721961, rs35652124, rs1048290, and rs11545829 conferred the susceptibility to CRC. The hypermethylation of KEAP1 promoter resulted in lower levels of KEAP1 messenger RNA (mRNA). After treatment with 5-aza-2'-deoxycytidine/trichostatin A, KEAP1 promoter methylation was decreased and KEAP1 mRNA levels were increased. ChIP-quantitative polymerase chain reaction results showed an enhanced enrichment of H3K4Me3 and H3K27Ac to the promoter of KEAP1. In vitro methylation analysis showed that the methylated plasmid decreased the transcriptional activity by 70%-84%. These findings suggest that the KEAP1- NRF2 pathway could potentially impact CRC risk and the downregulation of KEAP1 could be explained in part by epigenetic modifications.

MDM2 controls NRF2 antioxidant activity in prevention of diabetic kidney disease

Oxidative stress and P53 contribute to the pathogenesis of diabetic kidney disease (DKD). Nuclear factor erythroid 2-related factor 2 (NRF2) is a master regulator of cellular antioxidant defense system, is negatively regulated by P53 and prevents DKD. Recent findings revealed an important role of mouse double minute 2 (MDM2) in protection against DKD. However, the mechanism remained unclear. We hypothesized that MDM2 enhances NRF2 antioxidant signaling in DKD given that MDM2 is a key negative regulator of P53. The MDM2 inhibitor nutlin3a elevated renal P53, inhibited NRF2 signaling and induced oxidative stress, inflammation, fibrosis, DKD-like renal pathology and albuminuria in the wild-type (WT) non-diabetic mice. These effects exhibited more prominently in nutlin3a-treated WT diabetic mice. Interestingly, nutlin3a failed to induce greater renal injuries in the Nrf2 knockout (KO) mice under both the diabetic and non-diabetic conditions, indicating that NRF2 predominantly mediates MDM2's action. On the contrary, P53 inhibition by pifithrin-α activated renal NRF2 signaling and the expression of Mdm2, and attenuated DKD in the WT diabetic mice, but not in the Nrf2 KO diabetic mice. In high glucose-treated mouse mesangial cells, P53 gene silencing completely abolished nutlin3a's inhibitory effect on NRF2 signaling. The present study demonstrates for the first time that MDM2 controls renal NRF2 antioxidant activity in DKD via inhibition of P53, providing MDM2 activation and P53 inhibition as novel strategies in the management of DKD.

Transcription Factor NRF2 as a Therapeutic Target for Chronic Diseases: A Systems Medicine Approach

Systems medicine has a mechanism-based rather than a symptom- or organ-based approach to disease and identifies therapeutic targets in a nonhypothesis-driven manner. In this work, we apply this to transcription factor nuclear factor (erythroid-derived 2)-like 2 (NRF2) by cross-validating its position in a protein-protein interaction network (the NRF2 interactome) functionally linked to cytoprotection in low-grade stress, chronic inflammation, metabolic alterations, and reactive oxygen species formation. Multiscale network analysis of these molecular profiles suggests alterations of NRF2 expression and activity as a common mechanism in a subnetwork of diseases (the NRF2 diseasome). This network joins apparently heterogeneous phenotypes such as autoimmune, respiratory, digestive, cardiovascular, metabolic, and neurodegenerative diseases, along with cancer. Importantly, this approach matches and confirms in silico several applications for NRF2-modulating drugs validated in vivo at different phases of clinical development. Pharmacologically, their profile is as diverse as electrophilic dimethyl fumarate, synthetic triterpenoids like bardoxolone methyl and sulforaphane, protein-protein or DNA-protein interaction inhibitors, and even registered drugs such as metformin and statins, which activate NRF2 and may be repurposed for indications within the NRF2 cluster of disease phenotypes. Thus, NRF2 represents one of the first targets fully embraced by classic and systems medicine approaches to facilitate both drug development and drug repurposing by focusing on a set of disease phenotypes that appear to be mechanistically linked. The resulting NRF2 drugome may therefore rapidly advance several surprising clinical options for this subset of chronic diseases.

Genetic variants of SULT1A1 and XRCC1 genes and risk of lung cancer in Bangladeshi population

Lung cancer is one of the most frequently occurring cancers throughout the world as well as in Bangladesh. This study aimed to correlate the prognostic and/or predictive value of functional polymorphisms in SULT1A1 (rs9282861) and XRCC1 (rs25487) genes and lung cancer risk in Bangladeshi population. A case-control study was conducted which comprises 202 lung cancer patients and 242 healthy volunteers taking into account the age, sex, and smoking status. After isolation of genomic DNA, genotyping was done by polymerase chain reaction-restriction fragment length polymorphism method and the lung cancer risk was evaluated as odds ratio that was adjusted for age, sex, and smoking status. A significant association was found between SULT1A1 rs9282861 and XRCC1 rs25487 polymorphisms and lung cancer risk. In case of rs9282861 polymorphism, Arg/His (adjusted odds ratio = 5.06, 95% confidence interval = 3.05-8.41, p < 0.05) and His/His (adjusted odds ratio = 3.88, 95% confidence interval = 2.20-6.82, p < 0.05) genotypes were strongly associated with increased risk of lung cancer in comparison to the Arg/Arg genotype. In case of rs25487 polymorphism, Arg/Gln heterozygote (adjusted odds ratio = 4.57, 95% confidence interval = 2.79-7.46, p < 0.05) and Gln/Gln mutant homozygote (adjusted odds ratio = 4.99, 95% confidence interval = 2.66-9.36, p < 0.05) were also found to be significantly associated with increased risk of lung cancer. This study demonstrates that the presence of His allele and Gln allele in case of SULT1A1 rs9282861 and XRCC1 rs25487, respectively, involve in lung cancer prognosis in Bangladeshi population.

Perspectives of the Nrf-2 signaling pathway in cancer progression and therapy

The Nuclear factor erythroid2-related factor2 (Nrf2), a master regulator of redox homoeostasis, is a key transcription factor regulating a wide array of genes for antioxidant and detoxification enzymes. It protects organs from various kinds of toxic insults. On the other hand, activation of Nrf2 is also correlated with cancer progression and chemoresistance. Downregulation of Nrf2 activity has attracted an increasing amount of attention as it may provide an alternative cancer therapy. In this review, we examine recent studies on roles of Nrf2 in several pathophysiological conditions emphasising cancer. We discuss elaborately the current knowledge on Nrf2 regulation including KEAP1-dependent and KEAP1-independent cascades. KEAP1/Nrf2 system is a master regulator of cellular response against a variety of environmental stresses. We also highlight several tightly controlled regulations of Nrf2 by numerous proteins, small molecules, toxic metals, etc. In addition, we evaluate the possible therapeutic approaches of increasing chemosensitivity via modulating Nrf2 signaling.

Prognostic significance of TCF21 mRNA expression in patients with lung adenocarcinoma

Several prognostic indicators have shown inconsistencies in patients of different genders with lung adenocarcinoma, indicating that these variations may be due to the different genetic background of males and females with lung adenocarcinoma. In this study, we first used the Gene-Cloud of Biotechnology Information (GCBI) bioinformatics platform to identify differentially expressed genes (DEGs) that eliminated gender differences between lung adenocarcinoma and normal lung tissues. Then, we screened out that transcription factor 21 (TCF21) is a hub gene among these DEGs by creating a gene co-expression network on the GCBI platform. Furthermore, we used the comprehensive survival analysis platforms Kaplan-Meier plotter and PrognoScan to assess the prognostic value of TCF21 expression in lung adenocarcinoma patients. Finally, we concluded that decreased mRNA expression of TCF21 is a predictor for poor prognosis in patients with lung adenocarcinoma.

An overview of chemical inhibitors of the Nrf2-ARE signaling pathway and their potential applications in cancer therapy

The Nuclear factor erythroid 2-related factor 2 (Nrf2) is a key transcription factor regulating a wide array of genes for antioxidant and detoxification enzymes in response to oxidative and xenobiotic stress. A large number of Nrf2-antioxidant response element (ARE) activators have been screened for use as chemopreventive agents in oxidative stress-related diseases and even cancer. However, constitutive activation of Nrf2 occurs in a variety of cancers. Aberrant activation of Nrf2 is correlated with cancer progression, chemoresistance, and radioresistance. In this review, we examine recent studies of Nrf2-ARE inhibitors in the context of cancer therapy. We enumerate the possible Nrf2-inhibiting mechanisms of these compounds, their effects sensitizing cancer cells to chemotherapeutic agents, and the prospect of applying them in clinical cancer therapy.

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.

Genetic Polymorphisms of Transcription Factor NRF2 and of its Host Gene Sulfiredoxin (SRXN1) are Associated with Cerebrovascular Disease in a Finnish Cohort, the TAMRISK Study

Oxidative stress is involved in the pathophysiology of many cardiovascular disorders, such as hypertension and atherosclerosis. NRF2 is the primary transcriptional regulator of several antioxidant genes, including that of sulfiredoxin (SRXN1). The association of genotypes of NRF2 and SRXN1 with cardiovascular conditions was studied in a Finnish cohort of 336 subjects with diagnosed hypertension and 480 normotensive controls from the Tampere adult population cardiovascular risk study (TAMRISK). Samples were genotyped for four SNPs (rs1962142, rs2706110, rs6721961 and rs6706649) in the NRF2 gene region and four SNPs (rs6053666, rs6116929, rs2008022, rs6085283) in the SRXN1 gene region using Competitive Allele Specific PCR (KASP) technique. Cardiovascular diseases were followed up from 2005 to 2014 using the Finnish National Hospital Discharge Registry (HILMO). Four out of eight studied polymorphisms: rs6721961, rs1962142, rs2706110 of NRF2, and rs6053666 of SRXN1 were associated with cerebrovascular disease. NRF2 polymorphism rs6721961 showed association with hypertension. NRF2 and SRXN1 polymorphisms, previously thought to be associated with human disease, appear to be associated particularly with cerebrovascular disease.

Molecular basis of the Keap1-Nrf2 system

Nrf2 (NF-E2-related factor 2) is a master regulator of cellular responses against environmental stresses. Nrf2 induces the expression of detoxification and antioxidant enzymes, and Keap1 (Kelch-like ECH-associated protein 1), an adaptor subunit of Cullin 3-based E3 ubiquitin ligase, regulates Nrf2 activity. Keap1 also acts as a sensor for oxidative and electrophilic stresses. Keap1 retains multiple sensor cysteine residues that detect various stress stimuli. Increasing attention has been paid to the roles that Nrf2 plays in the protection of our bodies against drug toxicity and stress-induced diseases. On the other hand, Nrf2 is found to promote both oncogenesis and cancer cell resistance against chemotherapeutic drugs. Thus, although Nrf2 acts to protect our body from deleterious stresses, cancer cells hijack the Nrf2 activity to support their malignant growth. Nrf2 has emerged as a new therapeutic target, and both inducers and inhibitors of Nrf2 are awaited. Studies challenging the molecular basis of the Keap1-Nrf2 system functions are now critically important to improve translational studies of the system. Indeed, recent studies identified cross talk between Nrf2 and other signaling pathways, which provides new insights into the mechanisms by which the Keap1-Nrf2 system serves as a potent regulator of our health and disease.

Functional polymorphisms in Nrf2: implications for human disease

Nuclear factor (erythroid derived)-2 like 2 (NFE2L2), also known as nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2), is a ubiquitous transcription factor essential for protecting cells and tissues from oxidative stress-induced injury. Positional cloning and studies with Nrf2 knockout mice have identified important roles for this transcription factor in disease phenotypes for many organ systems. Studies have also characterized the means through which human Nrf2 is regulated and the mechanisms of interaction with antioxidant response elements (ARE) in promoters of effector genes. Moreover, single nucleotide polymorphisms (SNPs) in Nrf2 have been identified and evaluated for effects on gene expression and function, and translational investigations have sought to determine whether loss of function SNPs associate with disease progression. In this review, we present 1) an overview of the human Nrf2 gene and protein domain, 2) identification of genetic mutations in Nrf2 and associations of the mutations with multiple diseases, and 3) the role of somatic mutations in Nrf2 in diseases, primarily various cancers.

Antioxidant response genes sequence variants and BPD susceptibility in VLBW infants

BACKGROUND

Lung injury resulting from oxidative stress contributes to bronchopulmonary dysplasia (BPD) pathogenesis. Nuclear factor erythroid-2 related factor-2 (NFE2L2) regulates cytoprotective responses to oxidative stress by inducing enzymes containing antioxidant response elements (ARE). We hypothesized that ARE genetic variants will modulate susceptibility or severity of BPD in very-low-birth-weight (VLBW) infants.

METHODS

Blood samples obtained from VLBW infants were used for genotyping variants in the SOD2, NFE2L2, GCLC, GSTP1, HMOX1, and NQO1 genes. SNPs were genotyped utilizing TaqMan probes (Applied Biosystems (ABI), Grand Island, NY), and data were analyzed using the ABI HT7900. Genetic dominance and recessive models were tested to determine associations between SNPs and BPD.

RESULTS

In our cohort (n = 659), 284 infants had BPD; 135 of whom developed severe BPD. Presence of the hypomorphic NQO1 SNP (rs1800566) in a homozygous state was associated with increased BPD, while presence of the NFE2L2 SNP (rs6721961) was associated with decreased severe BPD in the entire cohort and in Caucasian infants. In regression models that adjusted for epidemiological confounders, the NQO1 and the NFE2L2 SNPs were associated with BPD and severe BPD, respectively.

CONCLUSION

Genetic variants in NFE2L2-ARE axis may contribute to the variance in liability to BPD observed in preterm infants. These results require confirmation in independent cohorts.

Role of the Keap1-Nrf2 pathway in cancer

The Kelch-like ECH-associated protein 1 (Keap1)-nuclear factor E2-related factor 2 (Nrf2) pathway is one of the major signaling cascades involved in cell defense and survival against endogenous and exogenous stress. While Nrf2 and its target genes provide protection against various age-related diseases including tumorigenesis, constitutively active Nrf2 in cancer cells increases the expression of cytoprotective genes and, consequently, enhances proliferation via metabolic reprogramming and inhibition of apoptosis. Herein, we review the current understanding of the regulation of Nrf2 in normal cells as well as its dual role in cancer. Furthermore, the mechanisms of Nrf2 dysregulation in cancer, consequences of unchecked Nrf2 activity, and therapies targeting the Keap1-Nrf2 system are discussed.

NFE2L2 Gene Variants and Arsenic Susceptibility: A Lymphoblastoid Model

Arsenic (As) exposure is a major risk for several types of cancer and metabolic diseases such as diabetes. The transcription factor nuclear factor erythroid 2-related factor (Nrf2) is a key mediator in the cellular defense against As-induced adverse effects. The -653G/A and -617C/A gene variants modulate expression levels of the Nrf2 coding gene (NFE2L2) and are postulated to be associated with several illnesses. In this study the functional effect of these polymorphisms was investigated in the cellular sensitivity to As-mediated effects. Using quantitative real-time polymerase chain reaction (qRT-PCR) the basal levels of NFE2L2 mRNA and the induced levels of NFE2L2 and its target gene NQO1 were measured in lymphoblastoid cells carrying different genotypes for -653G/A and -617C/A polymorphisms following As exposure. The effects of different NFE2L2 gene genotypes on cell proliferation were also explored after chronic metal exposure. A tendency toward reduction in basal levels of NFE2L2 mRNA was noted in the heterozygous (GA/CA) and risk homozygous (AA/AA) genotypes of both polymorphisms in immortalized lymphoblastoid cells. Although the expression of NFE2L2 and NQO1 after acute acute iAs exposure was not markedly influenced by -653G/A and -617C/A genotype, it was found that these single-nucleotide polymorphisms (SNPs) were correlated with a differential sensitivity to chronic exposure to the metalloid. Further studies are needed to completely understand the role of -653G/A and -617C/A SNPs in regulation of the NFE2L2 gene.

Genetic polymorphism in the NRF2 gene as a prognosis marker for cancer chemotherapy

NF-E2-related factor 2 (NRF2) is a transcription factor that controls the expression of a variety of antioxidant and detoxification genes. Accumulating evidence strongly suggests that NRF2 mediates cancer cell proliferation and drug resistance, as well. Single nucleotide polymorphism (SNP) -617C > A in the anti-oxidant response element-like loci of the human NRF2 gene play a pivotal role in the positive feedback loop of transcriptional activation of the NRF2 gene. Since the SNP (-617A) reportedly decreases the binding affinity to the transcription factors of NRF2/small multiple alignment format (MafK), the homozygous -617A/A allele may attenuate the positive feedback loop of transcriptional activation of the NRF2 gene and reduce the NRF2 protein level. As the consequence, cancer cells are considered to become more sensitive to therapy and less aggressive than cancer cells harboring the -617C (WT) allele. Indeed, Japanese lung cancer patients carrying SNP homozygous alleles (c. -617A/A) exhibited remarkable survival over 1,700 days after surgical operation (log-rank p = 0.021). The genetic polymorphism in the human NRF2 gene is considered as one of prognosis markers for cancer therapy.

Modulation of NRF2 signaling pathway by nuclear receptors: implications for cancer

Nuclear factor-erythroid 2 p45-related factor 2 (NRF2, also known as Nfe2l2) plays a critical role in regulating cellular defense against electrophilic and oxidative stress by activating the expression of an array of antioxidant response element-dependent genes. On one hand, NRF2 activators have been used in clinical trials for cancer prevention and the treatment of diseases associated with oxidative stress; on the other hand, constitutive activation of NRF2 in many types of tumors contributes to the survival and growth of cancer cells, as well as resistance to anticancer therapy. In this review, we provide an overview of the NRF2 signaling pathway and discuss its role in carcinogenesis. We also introduce the inhibition of NRF2 by nuclear receptors. Further, we address the biological significance of regulation of the NRF2 signaling pathway by nuclear receptors in health and disease. Finally, we discuss the possible impact of NRF2 inhibition by nuclear receptors on cancer therapy.

Association of NRF2 polymorphism with cholangiocarcinoma prognosis in Thai patients

Cholangiocarcinoma (CCA), a malignancy of biliary duct with a very poor prognosis, is the leading cause of cancer death in countries of the Mekong subregion. Liver fluke infection is the main etiological factor, but genetic variation has been recognized as also important in conferring susceptibility to CCA risk. Nuclear factor (erythroid derived 2)-like 2 (NRF2) is a key transcription factor in detoxification and antioxidant defense. Emerging evidence has demonstrated that genetic polymorphisms in the NRF2 gene may be associated with cancer development. The objectives of this study were to investigate the association of NRF2 genetic polymorphism with CCA risk and to evaluate the influence of the NRF2 genotype on survival time of affected patients. Single nucleotide polymorphisms (SNPs) of the NRF2 gene, including rs6726395: A/G, rs2886161: C/T, rs1806649: C/T, and rs10183914: C/T, were analyzed using TaqMan® SNP genotyping assays. Among 158 healthy northeastern Thai subjects, the allele frequencies were 41, 62, 94, and 92%, respectively. The correlation of NRF2 SNPs and CCA risk was analyzed in the 158 healthy subjects and 198 CCA patients, using unconditional logistic regression. The results showed that whereas the NRF2 SNPs were not associated with CCA risk (p>0.05), Kaplan-Meier analysis of 88 intrahepatic CCA patients showed median survival time with rs6726395 genotypes of GG and AA/AG to be 344±138 (95%CI: 73-615) days and 172±37 (95%CI: 100-244) days, respectively, (p<0.006). On multivariate Cox proportional hazard analysis, the GG genotype of rs6726395 was found to be associated with longer survival with a hazard ratio of 0.54 (95%CI: 0.31-0.94). In addition, non-papillary adenocarcinoma was associated with poor survival with a hazard ratio of 2.09 (95%CI: 1.16-3.75). The results suggest that the NRF2 rs6726395 polymorphism can be a potential prognostic biomarker for CCA patients.