Biochemical and Genetic Analysis of NAD(P)H:Quinone Oxidoreductase 1 (NQO1)

Siegel, David; Kepa, Jadwiga K.; Ross, David

doi:10.1002/0471140856.tx0422s32

Cited by 10 publications

(8 citation statements)

References 23 publications

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“…NQO1 activity was evaluated spectrophotometrically as previously described [ 18 ] using 2,6-dichloroindophenol (DCPIP) as a substrate. The assay was based on the activities for NAD(P)H-dependent reduction of DCPIP at 600 nm and the reaction was specifically inhibited by dicumarol.…”

Section: Methodsmentioning

confidence: 99%

A Case‐Control Study of Involvement of Oxidative DNA Damage and Alteration of Antioxidant Defense System in Patients with Basal Cell Carcinoma: Modulation by Tumor Removal

Chaisiriwong

Wanitphakdeedecha

Sitthinamsuwan

et al. 2016

Oxidative Medicine and Cellular Longevity

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Oxidative damage has been suggested to play a role in the pathogenesis of basal cell carcinoma (BCC). This study illustrated an involvement of oxidative DNA damage and changes in antioxidant defenses in BCC by conducting a case-control study (24 controls and 24 BCC patients) and assessing urinary 7,8-dihydro-8-oxo-2′-deoxyguanosine (8-oxo-dGuo), plasma antioxidant defenses including catalase (CAT), glutathione peroxidase (GPx), NQO1, and total superoxide dismutase (SOD) activities, and glutathione (GSH) levels before surgery and 1 month after surgery. 8-oxo-dGuo expressions as well as protein and mRNA expressions of DNA repair enzyme hOGG1 and antioxidant defenses (CAT, GCLC, GPx, Nrf2, and MnSOD) in nonneoplastic epidermis of control and BCC tissues were also determined. This study observed induction in urinary 8-oxo-dGuo, increased 8-oxo-dGuo expression, and reduced hOGG1 protein and mRNA in BCC tissues, decreased activities of CAT, GPx, and NQO1, but elevated SOD activities and GSH levels in BCC patients and reduction of all antioxidant proteins and genes studied in BCC tissues. Furthermore, decreased plasma antioxidant activities in BCC patients were restored at 1 month after operation compared with preoperative levels. Herein, we concluded that BCC patients were associated with oxidative DNA damage and depletion of antioxidant defenses and surgical removal of BCC correlated with improved redox status.

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Section: Methodsmentioning

confidence: 99%

A Case‐Control Study of Involvement of Oxidative DNA Damage and Alteration of Antioxidant Defense System in Patients with Basal Cell Carcinoma: Modulation by Tumor Removal

Chaisiriwong

Wanitphakdeedecha

Sitthinamsuwan

et al. 2016

Oxidative Medicine and Cellular Longevity

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“…At first, we examined whether depletion of Nrf2 using small-interfering RNA-mediated silencing of Nrf2 affected UVA-induced melanogenesis in primary human epidermal melanocytes (HEMn) and B16F10 melanoma cells. In addition, UVA irradiation was suggested to induce photodamaged skin through activation of MAPK signaling in association with oxidative stress responses in various types of skin cells [22] , [23] . Thus, the role of MAPK signaling as upstream mediators that could regulate Nrf2 nuclear translocation in response to UVA irradiation was also evaluated in this study.…”

Section: Introductionmentioning

confidence: 99%

Photoprotection by dietary phenolics against melanogenesis induced by UVA through Nrf2-dependent antioxidant responses

et al. 2016

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Dietary phenolics may play a protective role in UV-mediated skin pigmentation through their antioxidant and UV-absorbing actions. In this study, we investigated whether genetic silencing of Nrf2, regulating the transcription of antioxidant genes, affected melanogenesis in primary human epidermal melanocytes (HEMn) and B16F10 melanoma cells subjected to UVA (8 J/cm2) exposure. Then, we explored the antimelanogenic actions of phenolics; caffeic acid (CA) and ferulic acid (FA) providing partial UVA protection; quercetin (QU) and rutin (RU) providing strong UVA protection and; avobenzone (AV), an efficient UVA filter, in association with modulation of Nrf2-mediated antioxidant defenses in response to UVA insults in B16F10 cells. Upon oxidative insults, Nrf2 silencing promoted melanogenesis in both HEMn and B16F10 cells irradiated with UVA. Stimulation of melanogenesis by UVA correlated with increased ROS and oxidative DNA damage (8-OHdG), GSH depletion as well as a transient downregulation of Nrf2 nuclear translocation and of Nrf2-ARE signaling in B16F10 cells. All test compounds exerted antimelanogenic effects with respect to their abilities to reverse UVA-mediated oxidative damage as well as downregulation of Nrf2 activity and its target antioxidants (GCLC, GST and NQO1) in B16F10 cells. In conclusion, defective Nrf2 may promote melanogenesis under UVA irradiation through oxidative stress mechanisms. Compounds with antioxidant and/or UVA absorption properties could protect against UVA-induced melanogenesis through indirect regulatory effect on Nrf2-ARE pathway.

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“…For tissue, lysates were obtained as previously described by Siegel et al. [44] . Briefly, tissue was homogenized using a dounce homogenizer in RIPA buffer with a volume to weight ratio of 5:1.…”

Section: Methodsmentioning

confidence: 99%

“…NQO1 activity of samples was assayed as described previously by Siegel et al [44] . Briefly, tissues from young and old animals were prepared as described above before being assayed for the NAD(P)H-dependent reduction of DCPIP by NQO1 in the presence and absence of dicumarol (a reversible NQO1-specific inhibitor).…”

Section: Methodsmentioning

confidence: 99%

Glutathione maintenance mitigates age-related susceptibility to redox cycling agents

et al. 2016

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Isolated hepatocytes from young (4–6 mo) and old (24–26 mo) F344 rats were exposed to increasing concentrations of menadione, a vitamin K derivative and redox cycling agent, to determine whether the age-related decline in Nrf2-mediated detoxification defenses resulted in heightened susceptibility to xenobiotic insult. An LC50 for each age group was established, which showed that aging resulted in a nearly 2-fold increase in susceptibility to menadione (LC50 for young: 405 μM; LC50 for old: 275 μM). Examination of the known Nrf2-regulated pathways associated with menadione detoxification revealed, surprisingly, that NAD(P)H: quinone oxido-reductase 1 (NQO1) protein levels and activity were induced 9-fold and 4-fold with age, respectively (p=0.0019 and p=0.018; N=3), but glutathione peroxidase 4 (GPX4) declined by 70% (p=0.0043; N=3). These results indicate toxicity may stem from vulnerability to lipid peroxidation instead of inadequate reduction of menadione semi-quinone. Lipid peroxidation was 2-fold higher, and GSH declined by a 3-fold greater margin in old versus young rat cells given 300 µM menadione (p<0.05 and p≤0.01 respectively; N=3). We therefore provided 400 µM N-acetyl-cysteine (NAC) to hepatocytes from old rats before menadione exposure to alleviate limits in cysteine substrate availability for GSH synthesis during challenge. NAC pretreatment resulted in a >2-fold reduction in cell death, suggesting that the age-related increase in menadione susceptibility likely stems from attenuated GSH-dependent defenses. This data identifies cellular targets for intervention in order to limit age-related toxicological insults to menadione and potentially other redox cycling compounds.

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Biochemical and Genetic Analysis of NAD(P)H:Quinone Oxidoreductase 1 (NQO1)

Cited by 10 publications

References 23 publications

A Case‐Control Study of Involvement of Oxidative DNA Damage and Alteration of Antioxidant Defense System in Patients with Basal Cell Carcinoma: Modulation by Tumor Removal

A Case‐Control Study of Involvement of Oxidative DNA Damage and Alteration of Antioxidant Defense System in Patients with Basal Cell Carcinoma: Modulation by Tumor Removal

Photoprotection by dietary phenolics against melanogenesis induced by UVA through Nrf2-dependent antioxidant responses

Glutathione maintenance mitigates age-related susceptibility to redox cycling agents

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