NQO1 C609T polymorphism and esophageal cancer risk: a HuGE review and meta-analysis

The role of drug-metabolizing enzymes in synthetic lethality of cancer

Drug-metabolizing enzymes (DMEs) have shown increasing importance in anticancer therapy. It is not only due to their effect on activation or deactivation of anticancer drugs, but also because of their extensive connections with pathological and biochemistry changes during tumorigenesis. Meanwhile, it has become more accessible to discovery anticancer drugs that selectively targeted cancer cells with the development of synthetic lethal screen technology. Synthetic lethal strategy makes use of unique genetic markers that different cancer cells from normal tissues to discovery anticancer agents. Dysregulation of DMEs has been found in various cancers, making them promising candidates for synthetic lethal strategy. In this review, we will systematically discuss about the role of DMEs in tumor progression, the application of synthetic lethality strategy in drug discovery, and a link between DMEs and synthetic lethal of cancer.

Polymorphisms in NQO1 and MPO genes and risk for bladder cancer in Tunisian population

BACKGROUND

NAD (P) H: quinone oxidoreductase (1) (NQO1-HGNC: 2874) and myeloperoxidase (MPO-HGNC: 7218) are two enzymes involved in phase II of the xenobiotic metabolism pathway.

METHODS

In this study, a case-control analysis was conducted to investigate the relationship between genetic variations in the NQO1 (C609T, rs1800566; IVS1-27 C >G, rs689452) and MPO (G463A, rs2333227) genes and the risk for bladder cancer among Tunisian population.

RESULTS

We have found that the MPO 463GA genotype was associated with a decreased risk of developing bladder cancer (p = 0.049; OR = 0.696; 95% CI 0.484-0.999). In contrast, we have found that the NQO1 609CT genotype could increase the risk of bladder cancer patients (p = 0.0039; OR = 1.454; 95% CI = 1.017-2.078). Moreover, patients with "NQO1 609 CT/IVS1-27 CG" genotype show a 2.180-fold increasing risk for developing bladder cancer in comparison to the control group with wild genotype. This OR is estimated at 5.6-fold in smokers patients with "NQO1 609 CT/IVS1-27 CG" genotype. Lastly, study findings suggest that the NQO1 IVS-27 *CG genotype (rs689452) is associated with a risk of progression to muscle invasive bladder cancer.

CONCLUSION

Our study suggests that environmental risk factors in association to NQO1 genotypes (NQO1 609 CT/IVS1-27 CG) play an important role in the development of bladder cancer in Tunisian population.

Insights into the New Cancer Therapy through Redox Homeostasis and Metabolic Shifts

Modest levels of reactive oxygen species (ROS) are necessary for intracellular signaling, cell division, and enzyme activation. These ROS are later eliminated by the body’s antioxidant defense system. High amounts of ROS cause carcinogenesis by altering the signaling pathways associated with metabolism, proliferation, metastasis, and cell survival. Cancer cells exhibit enhanced ATP production and high ROS levels, which allow them to maintain elevated proliferation through metabolic reprograming. In order to prevent further ROS generation, cancer cells rely on more glycolysis to produce ATP and on the pentose phosphate pathway to provide NADPH. Pro-oxidant therapy can induce more ROS generation beyond the physiologic thresholds in cancer cells. Alternatively, antioxidant therapy can protect normal cells by activating cell survival signaling cascades, such as the nuclear factor erythroid 2-related factor 2 (Nrf2)-Kelch-like ECH-associated protein 1 (Keap1) pathway, in response to radio- and chemotherapeutic drugs. Nrf2 is a key regulator that protects cells from oxidative stress. Under normal conditions, Nrf2 is tightly bound to Keap1 and is ubiquitinated and degraded by the proteasome. However, under oxidative stress, or when treated with Nrf2 activators, Nrf2 is liberated from the Nrf2-Keap1 complex, translocated into the nucleus, and bound to the antioxidant response element in association with other factors. This cascade results in the expression of detoxifying enzymes, including NADH-quinone oxidoreductase 1 (NQO1) and heme oxygenase 1. NQO1 and cytochrome b5 reductase can neutralize ROS in the plasma membrane and induce a high NAD⁺/NADH ratio, which then activates SIRT1 and mitochondrial bioenergetics. NQO1 can also stabilize the tumor suppressor p53. Given their roles in cancer pathogenesis, redox homeostasis and the metabolic shift from glycolysis to oxidative phosphorylation (through activation of Nrf2 and NQO1) seem to be good targets for cancer therapy. Therefore, Nrf2 modulation and NQO1 stimulation could be important therapeutic targets for cancer prevention and treatment.

C/EBPβ mediates NQO1 and GSTP1 anti-oxidative reductases expression in glioblastoma, promoting brain tumor proliferation

Glioblastoma (GBM) is the most common and most aggressive brain tumor, associated with high levels of reactive oxidative species (ROS) due to metabolic and signaling aberrations. High ROS levels are detrimental to cells, but it remains incompletely understood how cancer cells cope with the adverse effects. Here we show that C/EBPβ, a ROS responsive transcription factor, regulates the transcription of NQO1 and GSTP1, two antioxidative reductases, which neutralize ROS in the GBM and mediates their proliferation. C/EBPβ is upregulated in EGFR overexpressed GBM cells, inversely correlated with the survival rates of brain tumor patients. Interestingly, C/EBPβ binds the promoters of NQO1 and GSTP1 and escalates their expression. Overexpression of C/EBPβ selectively decreases the ROS in EGFR-overexpressed U87MG cells and promotes cell proliferation via upregulating NQO1 and GSTP1; whereas knocking down C/EBPβ elevates the ROS and reduces proliferation by repressing the reductases. Accordingly, C/EBPβ mediates the brain tumor growth in vivo, coupling with NQO1 and GSTP1 expression and ROS levels. Hence, C/EBPβ regulates the expression of antioxidative reductases and balances the ROS, promoting brain tumor proliferation.

Esophageal cancer genetics in South Africa

Esophageal cancer (EC) is an extremely aggressive cancer with one of the highest mortality rates. The cancer is generally only diagnosed at the later stages and has a poor 5-year survival rate due to the limited treatment options. China and South Africa are two countries with a very high prevalence rate of EC. EC rates in South Africa have been on the increase, and esophageal squamous cell carcinoma is the predominant subtype and a primary cause of cancer-related deaths in the black and male mixed ancestry populations in South Africa. The incidence of EC is highest in the Eastern Cape Province, especially in the rural areas such as the Transkei, where the consumption of foods contaminated with Fusarium verticillioides is thought to play a major contributing role to the incidence of EC. China is responsible for almost half of all new cases of EC globally. In China, the prevalence of EC varies greatly. However, the two main areas of high prevalence are the southern Taihang Mountain area (Linxian, Henan Province) and the north Jiangsu area. In both countries, environmental toxins play a major role in increasing the chance that an individual will develop EC. These associative factors include tobacco use, alcohol consumption, nutritional deficiencies and exposure to environmental toxins. However, genetic polymorphisms also play a role in predisposing individuals to EC. These include single-nucleotide polymorphisms that can be found in both protein-coding genes and in non-coding sequences such as miRNAs. The aim of this review is to summarize the contribution of genetic polymorphisms to EC in South Africa and to compare and contrast this to the genetic polymorphisms observed in EC in the most comprehensively studied population group, the Chinese.

Esophageal Cancer in Golestan Province, Iran: A Review of Genetic Susceptibility and Environmental Risk Factors

Esophageal squamous cell carcinoma (ESCC) is an aggressive tumor that is typically diagnosed only when the tumor has gained remarkable size, extended to peripheral tissues, and led to dysphagia. Five-year survival of advanced cancer is still very poor (19%), even with improved surgical techniques and adjuvant chemoradiation therapy. Therefore, early detection and prevention are the most important strategies to reduce the burden of ESCC. Our review will focus on the studies conducted in Golestan province, an area with a high prevalence of ESCC in northern Iran. We review three aspects of the research literature on ESCC: epidemiological features, environmental factors (including substance abuse, environmental contaminants, dietary factors, and human papillomavirus [HPV]), and molecular factors (including oncogenes, tumor suppressor genes, cell cycle regulatory proteins, and other relevant biomarkers). Epidemiological and experimental data suggest that some chemicals and lifestyle factors, including polycyclic aromatic hydrocarbons (PAHs), cigarette smoking, opium use, and hot tea drinking are associated with the development of ESCC in Golestan. HPV infects the esophageal epithelium, but so far, no firm evidence of its involvement in esophageal carcinogenesis has been provided. Some of these factors, notably hot tea drinking, may render the esophageal mucosa more susceptible to injury by other carcinogens. There are few studies at molecular level on ESCC in Golestan. Increasing awareness about the known risk factors of ESCC could potentially reduce the burden of ESCC in the region. Further studies on risk factors, identifying high risk populations, and early detection are needed.

Development of esophageal cancer in Chaoshan region, China: association with environmental, genetic and cultural factors

Esophageal squamous cell carcinoma (ESCC) is the eighth most common cancer by incidence worldwide. Although the cancer is located at a readily recognizable and accessible site in the body, it is the sixth most common cause of cancer death. The 1- and 5-year survival rates in China are 50% and 15%, respectively. Furthermore, the cancer has distinct geographic and etiological risk factors in different locations around the world. Since ESCC is highly prevalent in the Chaoshan (Southeastern) region of China, this report will focus on a review of risk factors for the cancer in this area. From the review, it is clear that some important and traditional factors are involved, e.g. environmental mutagens, genetic predisposition. However, unique factors, e.g. the drinking of very hot tea, may play an important role. This review highlights the role of complex risk factors (environmental, genetic and cultural) which contribute to the multistage development of cancer: localized injury, inflammation, mitogenesis, mutagenesis, carcinogenesis and eventually mortality. The latter is contributed by unnecessary delay in seeking medical care which may be culturally related. The review emphasizes the need to identify causal mechanisms for the complex carcinogenic process which can provide opportunity for prevention and treatment of this potentially curable cancer.

Genetic polymorphism 609C>T in NAD(P)H:quinone oxidoreductase 1 enhances the risk of proximal colon cancer

Gastrointestinal (GI) cancer is responsible for the majority of deaths among all types of cancer. Lifestyle factors may not only be the main risk factor for GI cancer but reactive oxygen species (ROS) may also be involved. The single-nucleotide polymorphisms (SNPs) 609C>T (rs1800566) and 465C>T (rs1131341) in the

NAD(P)H

quinone oxidoreductase 1 (NQO1) gene lead to a decline in NQO1 enzyme activity. NQO1 catalyzes the two-electron reduction of quinones to hydroquinones, thereby preventing the formation of ROS. Such polymorphisms in NQO1 may increase the risk of GI cancer. The aim of this study was to evaluate the influence of the SNPs rs1800566 and rs1131341 in the NQO1 gene on the risk of GI cancer in the Netherlands. Real-time polymerase chain reaction techniques were conducted to determine the NQO1 genotypes of 1457 patients with GI cancer and 1457 age- and gender-matched controls in a case-control study. Binary logistic regression analyses showed no statistically significant difference in genotype distributions between patients and controls: odds ratios (ORs) with 95% confidence interval (CI) for rs1800566 were 1.09 (0.93-1.28) and 1.17 (0.77-1.77) for the CT and TT genotypes, respectively. ORs for rs1131341 CT and TT genotypes were 1.21 (0.90-1.63) and 0.54 (0.05-5.94), respectively. For rs1800566, a significant association between the CT genotype and proximal colon cancer was detected (OR=1.60; 95% CI=1.09-2.35). The NQO1*2 T allele of SNP rs1800566 was found associated with an increased risk for proximal colorectal cancer, whereas SNP rs1131341 was rare in our Dutch population and was not associated with GI cancer.

NQO1 rs1800566 C>T polymorphism was associated with a decreased risk of esophageal cancer in a Chinese population

BACKGROUND. Esophageal cancer was the fifth most commonly diagnosed cancer and the fourth leading cause of cancer-related death in China in 2009. Esophageal squamous cell carcinoma (ESCC) accounts for more than 90% of esophageal cancers. Genetic factors may play an important role in the carcinogenesis of ESCC. METHODS. We conducted a hospital-based case-control study to evaluate functional

NAD(P)H

quinone oxidoreductase 1 (NQO1) rs1800566 C>T and NQO2 rs2070999 G>A single-nucleotide polymorphisms on the risk of ESCC. A total of 629 patients with ESCC and 686 controls were recruited for this study. The genotypes were determined using the ligation detection reaction method. RESULTS. When the NQO1 rs1800566 CC homozygote genotype was used as the reference group, the TT genotype was associated with a significantly decreased risk of ESCC. In the recessive model, when the NQO1 rs1800566 CC/CT genotypes were used as the reference group, the TT homozygote genotype was associated with a 31% decreased risk of ESCC. A significantly decreased risk of ESCC was evident in patients with the NQO1 rs1800566 C>T polymorphism among females, those of a younger age (<63 years), those who had never smoked, those who consumed alcohol and those who did not. There was no association found between the NQO2 rs2070999 G>A polymorphism and ESCC risk. CONCLUSION. The NQO1 rs1800566 TT genotype was associated with a decreased risk of ESCC in a Chinese population. The association was evident among female patients, younger patients, patients who had never smoked, patients who consumed alcohol and those who did not. These findings need to be confirmed by repeating the study in a larger cohort of patients.

The NQO1 C609T polymorphism and hepatocellular carcinoma risk

NAD(P)H quinine oxidoreductase 1 (NQO1) enzyme plays a crucial role in the protection against oxidative stress. The polymorphism of NQO1 C609T has been implicated in the development of hepatocellular carcinoma (HCC). However, the findings were inconsistent due to different ethnicity, sample size, and source of controls in individual studies. To better estimate the association of NQO1 C609T polymorphism with HCC risk, we performed a meta-analysis of all currently available studies on the susceptibility to HCC. The meta-analysis included three independent studies with a total of 1, 595 subjects. The association was assessed under five different gene models. The overall analysis suggested that the variant allele and genotypes were significantly related to increased risk of HCC (ORT vs. C = 1.47, 95 % CI 1.07-2.00, P OR = 0.016; ORTT vs. CC = 2.06, 95 % CI 1.06-3.98, P OR = 0.032; ORTC vs. CC = 1.33, 95 % CI 1.06-1.67, P OR = 0.012; ORTT + TC vs. CC = 1.46, 95 % CI 1.19-1.81, P OR < 0.001; ORTT vs. CC + TC = 1.62, 95 % CI 1.25-2.09, P OR < 0.001). Stratified analyses in Asians and hospital-based case-control studies further demonstrated the significant correlation. Sensitivity analysis confirmed the reliability of these findings. Our study firstly shows that individuals carrying the NQO1 C609T variant allele and genotypes are more susceptible to HCC, particularly for Asians.

The clinical potential of influencing Nrf2 signaling in degenerative and immunological disorders

Nuclear factor (erythroid-derived 2)-like 2 (Nrf2; encoded in humans by the NFE2L2 gene) is a transcription factor that regulates the gene expression of a wide variety of cytoprotective phase II detoxification and antioxidant enzymes through a promoter sequence known as the antioxidant-responsive element (ARE). The ARE is a promoter element found in many cytoprotective genes; therefore, Nrf2 plays a pivotal role in the ARE-driven cellular defense system against environmental stresses. Agents that target the ARE/Nrf2 pathway have been tested in a wide variety of disorders, with at least one new Nrf2-activating drug now approved by the US Food and Drug Administration. Examination of in vitro and in vivo experimental results, and taking into account recent human clinical trial results, has led to an opinion that Nrf2-activating strategies – which can include drugs, foods, dietary supplements, and exercise – are likely best targeted at disease prevention, disease recurrence prevention, or slowing of disease progression in early stage illnesses; they may also be useful as an interventional strategy. However, this rubric may be viewed even more conservatively in the pathophysiology of cancer. The activation of the Nrf2 pathway has been widely accepted as offering chemoprevention benefit, but it may be unhelpful or even harmful in the setting of established cancers. For example, Nrf2 activation might interfere with chemotherapies or radiotherapies or otherwise give tumor cells additional growth and survival advantages, unless they already possess mutations that fully activate their Nrf2 pathway constitutively. With all this in mind, the ARE/Nrf2 pathway remains of great interest as a possible target for the pharmacological control of degenerative and immunological diseases, both by activation and by inhibition, and its regulation remains a promising biological target for the development of new therapies.

NQO1 C609T polymorphism is associated with esophageal cancer risk among Chinese: a meta-analysis

NAD(P)H

quinone oxidoreductase 1 (NQO1) C609T gene polymorphism has been reported to influence the risk for esophageal cancer (EC) in many studies; however, the results remain controversial and ambiguous. We therefore carried out a meta-analysis of published case-control studies to investigate the association between NQO1 C609T polymorphism and EC susceptibility. Electronic searches were conducted on links between this variant and EC in several databases. Odds ratios (ORs) and 95% confidence intervals (CIs) for homozygous, dominant model, recessive model and allele were calculated to estimate the strength of associations in fixed and random effect models. Heterogeneity and publication bias were also assessed. A total of 11 case-control studies were identified, including1,619 cases and 2,101 controls. C allele was associated with a decreased susceptibility risk of EC compared with the T allele among Chinese (OR = 0.70; 95% CI = 0.59-0.84). The contrast of homozygotes and the recessive and dominant models produced the same pattern of results as the allele contrast. Our pooled data suggest a significant association exists between NQO1 C609T polymorphism and EC among Chinese.

Association between NAD(P)H:quinone oxidoreductase 1 rs1800566 polymorphism and risk of bladder cancer

NAD(P)H

quinone oxidoreductase 1 (NQO1) rs1800566 (Pro187Ser) is a functional polymorphism which leads to a proline-to-serine amino acid substitution at codon 187 in the NQO1 protein and enzyme activity changes. NQO1 rs1800566 polymorphism was implicated to be associated with a risk of bladder cancer, but published studies showed inconclusive results. We performed a meta-analysis of nine publications with a total of 2,661 cases and 2,738 controls on the association between NQO1 rs1800566 polymorphism and risk of bladder cancer. Data were extracted from those included studies, and the pooled odds ratio (OR) with the corresponding 95% confidence interval (95% CI) was calculated to assess the association. We found that there was no association between NQO1 rs1800566 polymorphism and risk of bladder cancer under all four genetic models (Ser vs. Pro, OR = 1.06, 95% CI = 0.97-1.16, P = 0.21, I(2) = 31%; SerSer vs. ProPro, OR = 1.12, 95% CI = 0.89-1.42, P = 0.33, I(2) = 44%; SerSer/ProSer vs. ProPro, OR = 1.08, 95% CI = 0.96-1.21, P = 0.20, I(2) = 27%; SerSer vs. ProPro/ProSer, OR = 1.06, 95% CI = 0.85-1.32, P = 0.59, I(2) = 36%). Meta-analysis of those eight studies from Europeans also showed that there was no association between NQO1 rs1800566 polymorphism and risk of bladder cancer under all four genetic models (Ser vs. Pro, OR = 1.02, 95% CI = 0.93-1.13, P = 0.66, I(2) = 20%; SerSer vs. ProPro, OR = 0.99, 95% CI = 0.75-1.30, P = 0.93, I(2) = 38%; SerSer/ProSer vs. ProPro, OR = 1.04, 95% CI = 0.92-1.17, P = 0.55, I(2) = 6%; SerSer vs. ProPro/ProSer, OR = 0.98, 95% CI = 0.75-1.28, P = 0.87, I(2) = 39%). This meta-analysis suggests that the NQO1 rs1800566 polymorphism is not associated with a risk of bladder cancer. Further studies with larger samples are needed, especially for studies in Asians and Africans.