NADPH Quinone Oxidoreductase-1 Expression Research Articles

Regulation of Keap1-Nrf2 axis in temporal lobe epilepsy-hippocampal sclerosis patients may limit the seizure outcomes.

Accumulation of reactive oxygen species (ROS) exacerbates neuronal loss during seizure-induced excitotoxicity. Keap1 (Kelch-like ECH-associated protein1)-nuclear factor erythroid 2-related factor 2 (Nrf2) axis is one of the known active antioxidant response mechanisms. Our study focused on finding the factors influencing Keap1-Nrf2 axis regulation in temporal lobe epilepsy (TLE) associated with hippocampal sclerosis (HS) patients. Based on post-surgical follow-up data, patient samples (n = 26) were categorized into class 1 (completely seizure-free) and class 2 (only focal-aware seizures/auras), as suggested by International League Against Epilepsy (ILAE). For molecular analyses, double immunofluorescence assay and Western blot analysis were employed. A significant decrease in expression of Nrf2 (p < 0.005), HO-1; p < 0.02) and NADPH Quinone oxidoreductase1 (NQO1; p < 0.02) was observed in ILAE class 2. Keap1 (p < 0.02) and histone methyltransferases (HMTs) like SetD7 (SET7/9; SET domain-containing 7 histone lysine methyltransferase) (p < 0.009) and enhancer of zeste homolog 2 (EZH2; p < 0.02) and methylated histones viz., H3K4me1 (p < 0.001), H3K9me3 (p < 0.001), and H3K27me3 (p < 0.001) was upregulated in ILAE class 2. Nrf2-interacting proteins viz., p21 (p < 0.001) and heat shock protein 90 (HSP90; p < 0.03) increased in class 1 compared to class 2 patients. Upregulation of HMTs and methylated histones can limit phase II antioxidant enzyme expression. Also, HSP90 and p21 that interfere with Keap1-Nrf2 interaction could contribute to a marginal increase in HO-1 and NQO1 expression despite histone methylation and Keap1. Based on our findings, we conclude that TLE-HS patients prone to seizure recurrence were found to have dysfunctional antioxidant response, in part, owing to Keap1-Nrf2 axis. The significance of Keap1-Nrf2 signaling mechanism in generation of phase II antioxidant response. Keap1-Nrf2 controls antioxidant response through regulation of phase II antioxidant enzymes like HO-1 (heme oxygenase-1), NQO1 (NADPH-Quinone Oxidoreductase1), and glutathione S-transferase (GST). Release of Nrf2 from negative regulation by Keap1 causes its translocation into nucleus, forming a complex with cAMP response-element binding protein (CBP) and small Maf proteins (sMaf). This complex subsequently binds antioxidant response element (ARE) and elicits and antioxidant response involving expression of phase II antioxidant enzymes. Reactive oxygen species (ROS) modify Cysteine 151 residue, p62 (sequsetosome-1), and interacts with Nrf2- binding site in Keap 1. p21 and HSP90 prevent Nrf2 interaction with Keap1. At transcriptional level, histone methyltransferases like EZH2 (enhancer of zeste homologue2), and SetD7 (SET7/9; SET domain-containing 7 histone lysine methyltransferase) and corresponding histone targets viz., H3K27me3, H3K9me3, and H3K4me1 influence Nrf2 and Keap1 expression respectively.

MiR-485-5p Suppress the Malignant Characteristics of the Lung Adenocarcinoma via Targeting NADPH Quinone Oxidoreductase-1 to Inhibit the PI3K/Akt.

Lung adenocarcinoma (LUAD), a prevalent form of non-small cell lung cancer (NSCLC), has a high incidence and mortality rate. However, its molecular regulatory mechanisms have yet to be fully understood. The purpose of this study was to look into how NADPH quinone oxidoreductase-1 (NQO1) and it miR-485-5p and affected LUAD cells. The levels of miR-485-5p and NQO1 expression in LUAD cells and tissues were determined by means of quantitative reverse transcription polymerase chain reaction. The viability, proliferation, migration, and apoptosis of LUAD cells were assessed using cell counting Kit-8, 5-bromo-2'-deoxyuridine, transwell, and caspase-3 assays, respectively. Western blot experiments were used to examine the relative protein expression of matrix metallopeptidase 2 and matrix metallopeptidase 9, as well as the phosphorylation of phosphoinositide 3-kinase (PI3K) and protein kinase B (Akt) in LUAD cells. Luciferase and RNA pull-down experiments were also conducted for the verification of miR-485-5p's underlying relationship with NQO1. In our study, we found that LUAD cells and tissues had miR-485-5p downregulation and NQO1 upregulation. The experimental outcomes indicated that miR-485-5p overexpression in LUAD cells reduced their malignant behaviors, suppressed PI3K and Akt phosphorylation, and facilitated apoptosis. The results also revealed that NQO1 was a direct miR-485-5p target, and that NQO1 could reverse miR-485-5p's inhibitory effect on the malignant phenotype of LUAD cells. Furthermore, it was also observed that through targeting NQO1, miR-485-5p could suppress LUAD cell migration and proliferation, further blocking the phosphorylation of PI3K and Akt and inducing apoptosis among LUAD cells. In conclusion, the miR-485-5/NQO1 axis regulates LUAD progression through the PI3K/Akt pathway.

Exogenous spermine inhibits high glucose/oxidized LDL-induced oxidative stress and macrophage pyroptosis by activating the Nrf2 pathway.

Evidence suggests that macrophage pyroptosis promotes the progression of diabetic atherosclerosis. Spermine, a natural cellular metabolite, demonstrates a protective effect against cardiovascular diseases. However, whether spermine has a protective effect against macrophage pyroptosis caused by high glucose (HG) and oxidized low-density lipoprotein (ox-LDL) conditions remains to be elucidated. To investigate the protective effect of spermine and the related underlying mechanism, THP-1 macrophages were treated with HG/ox-LDL, spermine, or the specific nuclear factor erythroid 2-related factor 2 (Nrf2) inhibitor ML385. Cell viability was detected using CCK-8, cell membrane permeability was analyzed using lactate dehydrogenase (LDH) and Hoechst/propidium iodide staining and pyroptosis-related gene and protein expression levels were evaluated using polymerase chain reaction and western blot analysis. Spermine showed a potent preventive effect on THP-1 macrophage pyroptosis and oxidative stress induced by HG/ox-LDL. Cells treated with spermine showed increased cell viability, reduced reactive oxygen species (ROS) production, decreased LDH levels in the supernatant and reduced cell swelling. In addition, spermine significantly reduced NLR family pyrin domain containing 3, cleaved caspase-1, N-gasdermin D and IL-1β expression, as well as IL-1β levels in the supernatant. This demonstrated that the inhibition of pyroptosis and oxidative stress due to spermine was Nrf2 dependent. Furthermore, spermine enhanced Nrf2 nuclear translocation, thereby increasing heme oxygenase-1 and NADPH quinone oxidoreductase-1 expression, which subsequently reduced ROS production. In addition, the anti-pyroptotic and antioxidant effects of spermine were reversed by ML385 inhibition of Nrf2. It was concluded that spermine prevented macrophage pyroptosis and increased ROS overproduction by activating the Nrf2 pathway. The data suggested that spermine may be a potential novel drug for the treatment of diabetic atherosclerosis because it targets macrophage pyroptosis.

Association of NQO1 C609T (Pro187Ser) with Risk of Oral Submucous Fibrosis in Eastern Indian Population

Objective: Oral submucous fibrosis (OSF) is a debilitating disease mainly attributed to chewing areca nut with a 7.4-13% malignant transformation rate. The present study explores the role of NADPH quinone oxidoreductase 1 (NQO1) C609T (Pro187Ser) polymorphism in susceptibility to OSF among habitual areca nut chewers in an eastern Indian population. Material and Methods: In this hospital-based study, 152 controls and 179 OSF cases were genotyped at NQO1 C609T polymorphic site by PCR-RFLP and its effect on NQO1 expression in OSF tissue was studied to determine the risk of the disease. Results: Overall, about 18% of the total OSF cases were detected carrying minor TT alleles (Ser/Ser) p=0.026. When categorized by age, both CT (Pro/Ser) and TT (Ser/Ser) alleles were significantly higher (p= 0.003 &amp; 0.004 respectively) in cases above 40years of age. NQO1 protein was 42% reduced in buccal tissues of heterozygous (Pro/Ser) carriers, whereas a 70% reduction was observed in TT (Ser/Ser) OSF cases. Conclusion: Our study suggests that the NQO1 C609T polymorphism confers increased risk for OSF in habitual chewers.

NADPH: Quinone oxidoreductase 1 (NQO1) mediated anti-cancer effects of plumbagin in endocrine resistant MCF7 breast cancer cells

BackgroundPLB is a natural naphthoquinone compound isolated from the roots of Plumbago indica plant. Our previous study reported the inhibitory effect of Plumbagin (PLB) on human endocrine resistant breast cancer cell growth and cell invasion. Hypothesis/PurposeSince PLB is a naphthoquinone compound, it can be reduced by the cytosolic NADPH: quinone oxidoreductase 1 (NQO1) enzyme. NQO1 expression is upregulated in various types of aggressive cancer including breast cancer. This study investigated the impact of NQO1 on anti-cancer effects of PLB in endocrine-resistant breast cancer cells. Study DesignThis study was an in vitro study using ER-positive cell line (MCF7) and endocrine-resistant cell lines (MCF7/LCC2 and MCF7/LCC9 cells). MethodsThe roles of NQO1 in anti-cancer activity of PLB were investigated by using NQO1 knockdown cells, NQO1 inhibitor and NQO1 overexpressed cells. To study the impact of NQO1 on the effects of PLB on cell viability, apoptosis, invasion and generation of ROS, the following assays were used: MTT assays, annexin V-PE/7-ADD staining flow cytometry, matrigel invasion assays and DCFHDA assays. To study the mechanism of how NQO1 mediated PLB effects in tamoxifen response and apoptosis, we assessed the levels of mRNA expression by using qRT-PCR. Results1. In this study, NQO1 was upregulated in endocrine-resistant cells.2. PLB did not change the expression of NQO1 but it was able to increase NQO1 activity.3. The inhibitory effects of PLB on cell proliferation, cell invasion and expression of tamoxifen resistant gene were attenuated in NQO1 knockdown cells or in the presence of NQO1 inhibitor.4. The effects of PLB to induce apoptosis and generate ROS were also decreased when NQO1 activity was inhibited or when the NQO1 expression was reduced.5. The anti-cancer effects of PLB increased when NQO1 was upregulated. ConclusionThe effects of PLB in endocrine-resistant breast cancer cells is dependent on NQO1’s activity.

Nephroprotective effect of cilostazol and verapamil against thioacetamide-induced toxicity in rats may involve Nrf2/HO-1/NQO-1 signaling pathway

Cilostazol and verapamil are widely used cardiovascular drugs, explored a beneficial effect on different organs-induced toxicities. We investigated whether the Nrf2 (nuclear erythroid factor 2) and its downstream pathway are involved in the protective role of these drugs against TAA-induced renal damage. Renal biomarkers (creatinine and urea) and histopathology were observed. Antioxidant and oxidant indicators; superoxide dismutase (SOD), reduced glutathione (GSH), malondialdehyde (MDA) and total nitrite (NO) were also measured. Antioxidant markers like; Nrf2/hemoxegenase-1 (HO-1) and NADPH quinone oxidoreductase-1 (NQO-1) expressions were determined by ELISA and immunohistochemistry. Cilostazol and verapamil pretreatment improved serum creatinine and urea elevation. Examined drugs also have an ameliorative effect on TAA-induced elevation in MDA and NO activities and antioxidant enzymes; SOD and GSH. Additionally, the pretreated drugs significantly up-regulated Nrf2/HO-1/NQO-1 expression levels. In conclusion, cilostazol and verapamil exerted their protective effects partially via a Nrf2/HO-1/NQO-1 activation pathway with anti-oxidant roles.

Alzheimer's Disease and NQO1: Is there a Link?

Alzheimer's disease (AD) is a neurodegenerative disease characterised by a progressive decline in cognitive function and represents a major healthcare challenge worldwide. Increasing evidence indicates that mitochondrial dysfunction mediated oxidative stress plays a significant role in the pathophysiological process of AD. Therefore, the physiological activation of antioxidant enzymes that respond to increased oxidative stress is thought to prevent neuropathology. One of those endogenous defences is NADPH quinone oxidoreductase 1 (NQO1). NQO1 is a cytosolic homodimeric flavoprotein that catalyses the two-electron reduction of quinones and related molecules aimed at increasing their solubility and excretion. In line with its role as a phase II stress response protein, altered NQO1 expression is associated with several pathological conditions and disorders including AD. This review summarizes the association between NQO1 and AD pathology. Understanding this association will provide further insight into the pathogenesis of the disease. More importantly, recent interest in drugs that affect NQO1 expression or its activity provides hope that this approach could lead to novel therapeutic options for the treatment of AD.

Propofol post‐conditioning alleviates hepatic ischaemia reperfusion injury via BRG1‐mediated Nrf2/HO‐1 transcriptional activation in human and mice

To explore the effects of propofol post‐conditioning (PPC) on hepatic ischaemia/reperfusion injury (HIRI) and the potential mechanisms that might be involved in the interaction of Brahma‐related gene1(BRG1) and Nuclear‐related factor 2(Nrf2). Patients were randomized into PPC(n = 16) and non‐PPC(NPC)( n = 21) groups. Propofol(2 mg/kg) was infused within 10 min. of the onset of liver reperfusion during liver transplantation in the PPC group. Liver function tests, as well as Brg1, Nrf2, Heme oxygenase‐1(HO‐1) and NADPH:quinone oxidoreductase1(NQO1) expression levels were evaluated. CMV‐Brg1 mice were designed to investigate the role of Brg1 overexpression during HIRI. Brg1 and Nrf2 siRNA were used to examine the relationship between Brg1 and Nrf2/HO‐1 pathways in propofol‐mediated effects in a human hepatocyte(L02) hypoxia/reoxygenation(H/R) model. In patients, PPC attenuated both donor liver pathological and function injury, and reducing oxidative stress markers, compared to the NPC group, 24 hrs after surgery. PPC increased liver Brg1, Nrf2, HO‐1 and NQO1 expression. In mice, PPC reduced HIRI by decreasing liver oxidative stress and activating Nrf2/HO‐1 pathway, accompanied by up‐regulation of BRG1 expression. BRG1 overexpression activated Nrf2/HO‐1 transcription in CMV‐BRG1 mice during HIRI. In vitro, PPC significantly elevated expression of Nrf2, HO‐1 and NQO1, resulting in a reduction of cell DCFH‐DA and 8‐isoprostane levels and decreased lactate dehydrogenase levels, leading to an overall increase in cell viability. Moreover, the protective effects of propofol were partially abrogated in Nrf2‐knock‐down or BRG1‐knock‐down hepatocytes. Nrf2‐knock‐down drastically reduced protein expression of HO‐1 and NQO1, while Brg1‐knock‐down decreased HO‐1 expression. Propofol post‐conditioning alleviates HIRI through BRG1‐mediated Nrf2/HO‐1 transcriptional activation.

Evidence of activation of the Nrf2 pathway in multiple sclerosis patients treated with delayed-release dimethyl fumarate in the Phase 3 DEFINE and CONFIRM studies

Background: Delayed-release dimethyl fumarate (DMF) is an approved oral treatment for relapsing forms of multiple sclerosis (MS). Preclinical studies demonstrated that DMF activated the nuclear factor E2–related factor 2 (Nrf2) pathway. DMF and its primary metabolite monomethyl fumarate (MMF) were also shown to promote cytoprotection of cultured central nervous system (CNS) cells via the Nrf2 pathway. Objective: To investigate the activation of Nrf2 pathway following ex vivo stimulation of human peripheral blood mononuclear cells (PBMCs) with DMF or MMF, and in DMF-treated patients from two Phase 3 relapsing MS studies DEFINE and CONFIRM. Methods: Transcription of Nrf2 target genes NADPH:quinone oxidoreductase-1 (NQO1) and heme-oxygenase-1 (HO1) was measured using Taqman® assays. RNA samples were isolated from ex vivo–stimulated PBMCs and from whole blood samples of 200 patients each from placebo, twice daily (BID) and three times daily (TID) treatments. Results: DMF and MMF induced NQO1 and HO1 gene expression in ex vivo–stimulated PBMCs, DMF being the more potent inducer. Induction of NQO1 occurred at lower DMF concentrations compared to that of HO1. In DMF-treated patients, a statistically significant induction of NQO1 was observed relative to baseline and compared to placebo. No statistical significance was reached for HO1 induction. Conclusion: These data provide the first evidence of Nrf2 pathway activation from two large pivotal Phase 3 studies of DMF-treated MS patients.

Abstract A64: NQO1 depletion in non-small lung cancer cells decreases their tumorigenicity by reducing the ALDH (high) cancer stem cell population

Abstract Lung cancer is the leading cause of cancer related deaths in the world. In 2015, roughly 160,000 people in the U.S. alone will succumb to the disease. The high mortality is mainly due to late diagnosis and therapeutic resistance, followed by disease progression. One mechanism by which lung cancer is able to circumvent treatment is through the existence of cancer stem cells (CSCs). CSCs are a subpopulation of cells within the heterogenous tumor that are capable of self-renewal, are less sensitive to therapeutics and are believed to be responsible for disease progression, metastasis, and relapse. Aldehyde dehydrogenase (ALDH) high activity has been linked to the cancer stem cell phenotype in various cancers; and the elimination of cells within the heterogenous tumor that have ALDH (high) activity has been associated with decreased tumorigenicity. NADPH quinone oxidoreductase-1 (NQO1) is a two-electron oxidoreductase that is highly overexpressed in many cancers including non-small cell lung cancer. In normal cells NQO1 is expressed only at low levels, but plays a significant role in regulating oxidative stress. Thus, we hypothesized that the noted overexpression of NQO1 in most cancers may be due to its critical role in tumor survival. Specifically, in balancing the noted elevated levels of oxidative stress observed in cancer cells. Thus, reducing NQO1 expression in tumor cells may tip the balance towards pro-death instead of pro-survival. In our studies we used two different shRNA constructs to deplete NQO1 expression and assayed the ability of the knockdown cells to perform in assays that define a tumors ability to participate in disease progression. In brief, our data showed that NQO1 depleted non-small cell lung cancer cell lines had decreased colony formation in soft agar assays, increased detachment induced cell death (anoikis), increased oxidative stress and increased apoptosis. In addition, shNQO1 knockdown caused a depletion in ALDH (high) activity, suggesting that the cancer stem cell population was reduced due to the loss of NQO1 expression. Our in vivo data supported our in vitro data since athymic mice bearing shQNO1 tumors had significantly longer long-term survival and less tumor growth as compared to mice bearing vector-control tumors. In conclusion, our data strongly suggest that NQO1 depletion is a viable target for lung cancer stem cell reduction. Furthermore, our data suggest that implementation of NQO1-directed therapies to reduce cancer stem cells will lead to improved survival in patients whose tumors overexpress NQO1. Citation Format: Brian Madajewski, Michael A. Boatman, Erik A. Bey. NQO1 depletion in non-small lung cancer cells decreases their tumorigenicity by reducing the ALDH (high) cancer stem cell population. [abstract]. In: Proceedings of the Eighth AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 13-16, 2015; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2016;25(3 Suppl):Abstract nr A64.

The cytoprotective effects of ethanol extract of Ecklonia cava against oxidative stress are associated with upregulation of Nrf2-mediated HO-1 and NQO-1 expression through activation of the MAPK pathway.

The aim of the present study was to examine the cytoprotective effect of Ecklonia cava against oxidative stress in C2C12 myoblasts. The ethanol extract of E. cava (EEEC) prevented hydrogen peroxide (H₂O₂)-induced inhibition of the growth of C2C12 myoblasts and exhibited scavenging activity against intracellular reactive oxygen species (ROS) induced by H₂O₂. EEEC treatment attenuated H2O2-induced comet tail formation and phospho-histone γH2A.X expression. Furthermore, EEEC treatment enhanced the level of the phosphorylated form of nuclear factor erythroid 2- related factor 2 (Nrf2) and its nuclear translocation, which was associated with the induction of heme oxygenase-1 (HO-1) and NADPH-quinone oxidoreductase 1 (NQO-1). Zinc protoporphyrin IX, a HO-1 competitive inhibitor, significantly abolished the protective effects of EEEC against H₂O₂-induced ROS generation and growth inhibition in C2C12 myoblasts. Transient transfection with Nrf2-specific small interfering RNA restored the elevated HO-1 and NQO-1 expression and the phosphorylation of Nrf2 to near normal levels. The EEEC treatment also induced the activation of mitogen-activated protein kinases (MAPKs), and specific inhibitors of MAPKs abolished upregulated HO-1 and NQO-1, as well as the phosphorylation of Nrf2. Taken together, these data suggest that EEEC attenuates oxidative stress by activating Nrf2-mediated HO-1 and inducing NQO-1 via the activation of MAPK signaling pathways.

Systemic inflammation and oxidative stress in hemodialysis patients are associated with down-regulation of Nrf2.

Oxidative stress and inflammation are common features and the main mediators of progression of chronic kidney disease (CKD) and its cardiovascular complications. Under normal conditions, oxidative stress activates the transcription factor, nuclear factor E2-related factor 2 (Nrf2), which is the master regulator of genes encoding antioxidant and detoxifying enzymes and related proteins. The available data on expression of Nrf2 and its key target gene products in CKD patients is limited. We therefore investigated this topic in a group of CKD patients on hemodialysis. Twenty adult hemodialysis (HD) patients (aged 54.9 ± 15.2 years) and 11 healthy individuals (aged 50.9 ± 8.0 years) were enrolled. Peripheral blood mononuclear cells (PBMC) were isolated and processed for expression of nuclear factor-κB (NF-κB), Nrf2, heme oxygenase-1 and NADPH: quinoneoxidoreductase 1 (NQO1) by quantitative real-time polymerase chain reaction and western blot analysis. Plasma malondialdehyde (MDA) and tumor necrosis factor-alpha (TNF-α) levels were measured. Peripheral blood mononuclear cells from HD patients had significantly lower NQO1 and Nrf2 mRNA expressions (0.58 ± 0.35 vs. 1.13 ± 0.64, p = 0.005), and significantly higher NF-κB expression (2.18 ± 0.8 vs. 1.04 ± 0.22, p = 0.0001) compared to the healthy individuals. The NF-κB expression was inversely correlated with Nrf2 levels (r = -0.54, p < 0.01) in CKD patients. Plasma MDA and TNF-α levels were significantly higher in CKD patients than in the healthy individuals. Up-regulation of NFκB in the CKD patients' PBMC is coupled to down-regulation of Nrf2 and NQO1 expression. These observations are consistent with recent findings in CKD animals and point to the contribution of the impaired Nrf2 system in the pathogenesis of oxidative stress and inflammation in hemodialysis patients.

Nrf2 activation in the liver of rats subjected to a preconditioning sub-chronic iron protocol

Sub-chronic iron (Fe) administration induces liver oxidative stress upregulating cytoprotective mechanisms that may involve redox-sensitive nuclear factor erythroid 2-related factor 2 (Nrf2). We aimed to investigate whether Fe activates Nrf2, in relation to its negative regulator Kelch-like ECH associated protein 1 (Keap1), with consequent antioxidant enzyme induction. Sprague-Dawley rats received six Fe doses (50 mg kg(-1)) on alternate days or saline (controls), a protocol that abrogates ischemia-reperfusion liver injury. Liver reduced glutathione (GSH) content and Nrf2 (Western blot) were measured 24 h after each Fe dose. Increased hepatic Fe deposition (Perls staining) was paralleled by reversible GSH depletion and enhancements in nuclear Nrf2 content and in nuclear/cytosolic Nrf2 ratios. A similar profile was observed for heme oxygenase-1 (HO-1) and NADPH-quinone oxidoreductase 1 (NQO-1) contents, antioxidant enzymes that significantly correlated with nuclear/cytosolic Nrf2 ratios. Normalization of Fe-induced oxidative stress status occurred concomitantly with that of Nrf2 and with the Nrf2-dependent HO-1 and NQO-1 expression, which are associated with delayed enhancement in cytosolic Keap1 levels. This is in agreement with the significant inverse correlation of nuclear/cytosolic Nrf2 ratios with those of nuclear Keap1/Nrf2, suggesting a negative feed-back mechanism normalizing Nrf2 signaling. In conclusion, sub-chronic Fe administration leads to transient liver oxidative stress development and Nrf2 activation, as evidenced by early GSH depletion, enhanced nuclear Nrf2 protein levels, and HO-1 and NQO-1 induction, with late normalization of these changes being related to Keap1 upregulation.

235 - Correlation of C609T Polymorphism of Nadph Quinone Oxidoreductase 1 and Hematological Toxicities in Lung Cancer Patients Treated With Amrubicin

ABSTRACT Background Amrubicin hydrochloride (AMR) is a novel synthetic aminoanthracycline derivative, that is metabolically activated to amrubicinol (AMR-OH) by carbonyl reductase. The cytotoxic activity of AMR-OH is promising for small cell lung cancer and considered as a key agent. NADPH Quinone Oxidoreductase 1 (NQO1) is a cytosolic flavoprotein that metabolizes the quinone structures contained in both AMR and AMR-OH. NQO1 expression genotyped homozygous for minor alleles (T/T) was low compared with homozygous for major alleles (C/C) or heterozygous (C/T). We hypothesized that NQO1 C609T polymorphisms may relate to the AMR pharmacokinetics and clinical outcomes. Methods The patients with lung cancer received AMR at a dose of 30 or 40mg/m2/day on day 1-3 at Osaka City University Hospital were enrolled. Plasma sampling was performed at the time points of 24h after the third AMR injection. The concentrations of AMR and AMR-OH were determined by HPLC method. NQO1 C609T polymorphism was assayed using real-time polymerase chain reaction methods. Results A total of 35 patients were enrolled. The C/C, C/T, and T/T were observed in 12 (34.3%), 16 (45.7%), and 7 (20%) patients, respectively. A dose of 30 mg/m2 was administered to 19 patients, and 40mg/m2 was administered to 16 patients. The mean plasma concentrations of AMR-OH on day4 at a dose of 30mg/m2 and 40mg/m2 were 11.02 ± 3.83 and 16.18 ± 6.17 ng/ml, respectively (p = 0.005). In patients with AMR at a dose of 40mg/m2, the plasma concentrations of AMR-OH on day4 exhibited a tendency toward a relationship with NQO1 genotypes with values of C/C 20.5 ± 5.89, C/T 15.9 ± 5.43, and T/T 11.2 ± 4.47ng/ml (p = 0.066). The C/C was related to decrease changes in WBC, hemoglobin, and platelet counts (p = 0.01, p = 0.03, and p = 0.0005, respectively). No significant correlations were observed between NQO1 genotypes and clinical outcomes at a dose of 30mg/m2. Conclusions NQO1 C609T polymorphism had a tendency of correlation with the plasma concentrations of AMR-OH, and thereby had significant correlations with hematologic toxicities. NQO1 genotype appears to be the candidate biomarker of hematological toxicities of AMR treatment at a dose of 40mg/m2. Disclosure All authors have declared no conflicts of interest.

QS459. Heme Oxygenase-1 and NADPH Quinone Oxidoreductase-1 Expression is Enhanced by Flaxseed in a Mouse Model of Lung Ischemia Reperfusion Injury

QS459. Heme Oxygenase-1 and NADPH Quinone Oxidoreductase-1 Expression is Enhanced by Flaxseed in a Mouse Model of Lung Ischemia Reperfusion Injury

The significance of Nrf2 pathway in (photo)‐oxidative stress response in melanocytes and keratinocytes of the human epidermis

The expression of genes encoding antioxidant and/or phase 2 detoxifying enzymes can be enhanced in response to various environmental stresses. The main transcription factor involved in this response is nuclear factor erythroid 2-related factor 2 (Nrf2). Nrf2 activity is negatively regulated by the protein Kelch-like-Ech-associated-protein 1 (Keap1). While the roles of Nrf2 and phase 2 genes in chemoprevention of carcinogenesis have been well described; only few studies have dealt with their role in skin cancer. Normal human keratinocytes (NHK) and melanocytes (NHM) were treated by chemical inducers of the Nrf2 pathway or by small interfering RNAs (siRNA) used to knock down Keap1 mRNA. The above treatments resulted in significant stimulation of NQO-1 (NADPH-Quinone-Oxidoreductase 1) gene expression. GCL (gamma-Glutamyl-cysteinyl-ligase) gene was also induced but interestingly increased mRNA encoding the catalytic, heavy subunit GCLC was mainly stimulated in NHK, whereas the mRNA encoding the modifier, light subunit GCLM was mostly induced in NHM. HO-1 (Heme Oxygenase 1) gene induction was relatively strong in NHM, but generally absent in NHK, except when the cells were subjected to cytotoxic doses of the above chemicals. Exposure to solar UV (UVB + UVA, 300-400 nm) or to UVA alone (320-400 nm) confirmed this trend, but interestingly, at doses where cell growth reduction was comparable, UVA was generally more efficient than solar UV in inducing phase 2 genes. When siRNAs directed against Nrf2 were used, a strong down-regulation of NQO-1 expression was observed in both, NHM and NHK, whereas reduction of HO-1 expression was mainly detected in NHM. To our knowledge, this is the first study comparing phase 2 gene modulation in NHK and NHM. The results hereby presented should contribute to a better understanding of the molecular mechanisms involved in skin adaptation to environmental stress.