Nrf2 is the key transcription factor mainly for regulating oxidative homeostasis and cytoprotective responses against oxidative stress. Nrf2/Keap1 pathway is one of the most important cellular defense mechanisms against endogenous or exogenous oxidative stress. With its activation, a wide range of stress-related genes is transactivated to restore the cellular homeostasis. Recent studies revealed that the aberrant activation of Nrf2 is related to the malignant progression, chemotherapeutic drug resistance and poor prognosis. Nrf2 plays a crucial role in cancer malignancy and chemotherapeutic resistance by controlling the intracellular redox homeostasis through the activation of cytoprotective antioxidant genes. Nrf2 inhibitor containing many natural products has been deemed as a novel therapeutic strategy for human malignancies. This article reviews the progress of studies of the Nrf2/Keap1 pathway, and its biological impact in solid malignancies and molecular mechanisms for causing Nrf2 hyperactivation in cancer cells. In conclusion, we summarized the deve-lopment of Nrf2 inhibitors in recent years, in the expectation of providing reference for further drug development and clinical studies.
Humans ; Kelch-Like ECH-Associated Protein 1/metabolism* ; NF-E2-Related Factor 2/metabolism* ; Neoplasms/genetics* ; Oxidation-Reduction ; Oxidative Stress

The present study analyzed the correlations between curcumin(Cur), nuclear factor E2 related factor 2(NRF2)-dimethylarginine dimethylaminohydrolase(DDAH)-asymmetric dimethylarginine(ADMA)-nitric oxide(NO) pathway, and endothelial-mesenchymal transition(EndMT) based on SD rats with cardiac fibrosis, and explored the effect and mechanism of Cur in resisting cardiac fibrosis to provide an in-depth theoretical basis for its clinical application in the treatment of heart failure. The cardiac fibrosis model was induced by subcutaneous injection of isoprenaline(Iso) in rats. Thirty-two rats were randomly divided into a control group, a model group, a low-dose Cur group(100 mg·kg~(-1)·d~(-1)), and a high-dose Cur group(200 mg·kg~(-1)·d~(-1)), with eight in each group. After 21 days of treatment, cardiac function was detected by echocardiography, degree of cardiac fibrosis by Masson staining, expression of CD31 and α-SMA by pathological staining, expression of VE-cadherin, vimentin, NRF2, and DDAH by Western blot, and ADMA level by HPLC. Compared with the model group, the Cur groups showed alleviated cardiac fibrosis, accompanied by increased CD31 and VE-cadherin expression and decreased α-SMA and vimentin expression, indicating relieved EndMT. Additionally, DDAH and NRF2 levels were elevated and ADMA and NO expression declined. Cur improves cardiac fibrosis by inhibiting EndMT presumedly through the NRF2-DDAH-ADMA-NO pathway.
Amidohydrolases/metabolism* ; Animals ; Curcumin ; Fibrosis ; NF-E2-Related Factor 2/genetics* ; Nitric Oxide/metabolism* ; Rats ; Rats, Sprague-Dawley

The present study aimed to explore the effect of nuclear factor erythroid 2 related factor 2(Nrf2)/heme oxygenase-1(HO-1) signaling pathway in intestinal protection by Sishen Pills against ulcerative colitis(UC). After the UC model was induced by 3% dextran sodium sulfate(DSS), experimental animals were randomly divided into control group, model group, salazosulfapyridine(SASP) group, and low-and high-dose Sishen Pills groups. Drug intervention(ig) was performed for seven consecutive days during modeling. On the 7 th day, the mice were euthanized. The body weight and colon length were recorded, and the histopathological changes of the colon were observed by HE staining. Serum interleukin-6(IL-6), tumor necrosis factor-α(TNF-α), total antioxidant capacity(T-AOC), malondialdehyde(MDA), and reactive oxygen species(ROS) were detected by ELISA. The protein and mRNA expression of Nrf2, HO-1, and NADPH quinine oxidoreductase-1(NQO-1) was determined by Western blot and reverse transcription-polymerase chain reaction(RT-PCR). Compared with the normal group, the model group exhibited reduced body weight, colon length, and T-AOC, increased IL-6, TNF-α, MDA, and ROS, and diminished protein and mRNA expression of Nrf2, HO-1, and NQO-1 in the colon tissues. Compared with the model group, the SASP group and high-dose Sishen Pills group showed elevated body weight, colon length, and T-AOC, lowered IL-6, TNF-α, MDA, and ROS levels, and increased protein and mRNA expression of Nrf2, HO-1, and NQO-1 in the colon tissues. As assessed by HE staining, Sishen Pills could improve the pathological changes of the colon. The findings suggested that Sishen Pills could protect the colon against UC induced by 3% DSS. The specific mechanism of action may be related to the anti-inflammatory and anti-oxidative stress effects by the activation of the Nrf2/HO-1 signaling pathway.
Animals ; Colitis, Ulcerative/genetics* ; Dextran Sulfate ; Heme Oxygenase-1/metabolism* ; Mice ; NF-E2-Related Factor 2/metabolism* ; Signal Transduction

This study aimed to investigate the effect and the possible mechanism of Shenlian( SL) extract on tumor necrosis factor-α( TNF-α)-induced ECV304 injury. After the establishment of TNF-α-induced ECV304 cells injure model,MTT assay was used to detect cell viability and the level of reactive oxygen species( ROS) was measured by flow cytometry. The contents of superoxide dismutase( SOD),malondialdehyde( MDA),nitric oxide( NO),endothelin-1( ET-1) and interleukin-1β( IL-1β) in the supernatant were detected by biochemical method and enzyme linked immunosorbent assay( ELISA). The expression levels of apoptosis-related proteins B-lymphoma-2 gene( Bcl-2),Bcl-2 associated X protein( Bax),caspase-3,caspase-9 and nuclear factor E2 associated factor2( Nrf2)/Kelch like epichlorohydrin associated protein-1( Keap1) signaling pathway related proteins Nrf2,Keap1,quinone oxidoreductase( NQO1) and heme oxygenase 1( HO-1) were detected by Western blot. The results showed that 50 μg·L-1 TNF-α significantly damaged ECV304 cells,induced the impairment of cell viability( P<0. 01),the increase of ROS production,the decrease of SOD activity,and the increase of MDA,NO,ET-1 and IL-1β( P<0. 01),meanwhile,it caused the up-regulation of Keap1,caspase-9 and Bax protein expression,and down-regulation of NQO1 and Bcl-2 protein expression( P<0. 05) compared with the control group.Compared with the model group,SL extract reduced the damage of ECV304 cells induced by TNF-α,improved cell viability,reduced ROS production,increased SOD activity and decreased MDA,NO,ET-1,IL-1β content( P<0. 01 or P<0. 05). In addition,SL extract also down-regulated the protein expression levels of Keap1,caspase-3,caspase-9 and Bax,and increased the protein expressions of Nrf2,NQO1,HO-1 and Bcl-2( P<0. 01 or P<0. 05). The above results indicate that SL extract can provide protective effect on ECV304 cells injury induced by TNF-α,alleviate oxidative stress injury,inflammation and apoptosis,and its mechanism may be related to regulating Nrf2/Keap1 signaling pathway.
Apoptosis ; Kelch-Like ECH-Associated Protein 1/metabolism* ; NF-E2-Related Factor 2/metabolism* ; Oxidative Stress ; Plant Extracts ; Signal Transduction ; Tumor Necrosis Factor-alpha/genetics*

AIMTo investigate the effects of Nrf2 (Nuclear-E2 related factor) on gamma-glutamylcysteine synthase (gamma-GCS) in lung of guinea pigs with bronchial asthma.

METHODS20 adult male guinea pigs were randomly divided into two groups (n = 10): control group (C group) and asthmatic group (A group), asthmatic model was established by ovalbumin intraperitoneal and ovalbumin inhalation. The reactive oxygen piece (ROS), reduced glutathione (GSH), oxidant glutathione (GSSG) and total GSH in lung tissue were examined respectively. Inflammatory cell infiltration and index of remodeling of bronchiole were detected. In situ hybridization detected the gamma-GCS heavy subunit (gamma-GCS h) mRNA in lung tissue. Immunohistochemistry detected the expression of Nrf2 protein and gamma-GCS protein in lung tissue. RT-PCR measured the expression of Nrf2 mRNA in lung tissue. The activity of gamma-GCS was measured by coupled enzyme assay.

RESULTS(1) The number of eosinophils and lymphocytes in bronchiole of A group were significantly higher than that of C group (P < 0.05), the remodeling of bronchiole in A group was definite. (2) ROS (U/mg pro), GSSG (micromol/g pro) and total GSH in lung tissue of A group were significantly higher than that of C group (P < 0.01). The GSH/GSSG in lung tissue of A group was much lower than that of C group (P < 0.01), GSH in lung tissue showed no difference between A group and C group. (3) Immunohistochemistry indicated that Nrf2 protein and gamma-GCS protein were more positively expressed in A group than that in C group (P < 0.01). In situ hybridization discovered that the expression of gamma-GCS-h mRNA in lung tissue of A group was more positive than that of C group. (4) RT-PCR showed that the expression of Nrf2 mRNA was no difference between A group and C group (P > 0.05). (5) The activity of gamma-GCS of A group was (28 +/- 8)U which was significantly higher than that of C group (9 +/- 2)U (P < 0.01). (6) Linear correlation analysis indicated that in lung tissue of guinea pig with asthma there existed strongly positive relationship among ROS, GSSG and the expression of Nrf2, gamma-GCS mRNA, gamma-GCS protein, the activity of gamma-GCS, there existed strongly negative relationship among GSH/GSSG and the expression of Nrf2, gamma-GCS mRNA, gamma-GCS protein, the activity of gamma-GCS.

CONCLUSIONThere existed oxidative stress in lung of guinea pigs with bronchial asthma, which possibly positively regulated gamma-GCS via up regulating transcription factor Nrf2.

Animals ; Asthma ; metabolism ; Glutamate-Cysteine Ligase ; metabolism ; Guinea Pigs ; Lung ; metabolism ; Male ; NF-E2-Related Factor 2 ; metabolism ; Oxidative Stress ; RNA, Messenger ; genetics

OBJECTIVETo investigate the expressions of PPAR-gamma/PGC-1alpha and Nrf2/gamma-GCS-h in lung of guinea pigs with bronchial asthma, and to explore the roles of them.

METHODSForty adult male guinea pigs were randomly divided into 4 groups: the control group (group A), asthmatic group ( group B), dexamethasone group (group C) and rogridone group (group D), 10 guinea pigs in each group. The asthmatic model was established by the ovalbumin challenge method. Expressions of PPAR-gamma/PGC-1alpha and Nrf2/gamma-GCS-h mRNA in lung tissue were assayed by in situ hybridization. Expressions of PPAR-gamma/PGC-1alpha and Nrf2/gamma-GCS-h protein were detected by immunohischemistry and by Western blot.

RESULTSIn situ hybridization showed that the expressions of PPAR-gamma/PGC-1alpha and Nrf2/gamma-GCS-h mRNA in lung tissue were the lowest in group B and the comparison among groups showed statistical significant (all P < 0.01). Immunohistochemistry and Western blot indicated that the value of PPAR-gamma/PGC-1alpha and Nrf2/gamma-GCS-h protein in lung tissue were the lowest in group B, and expressed primarily in nucleus, the differences being statistically significant (all P < 0.01). There was positive correlation between PPAR-gamma and PGC-1. gamma-GCS-h mRNA also positively correlated between PPAR-gamma/PGC-1alpha and Nrf2 in nucleus, and the expression of Nrf2 was also positively correlated with PPAR-gamma/ PGC-1alpha.

CONCLUSIONIn acute asthmatic models induced by ovalbumin, the expressions of PPAR-alpha/PGC-1alpha and Nrf2/gamma-GCS-h were decreased, and PPARgamma/PGC-1alpha could up-regulate the expressions of Nrf2/gamma-GCS-h to increase the antioxidant defense of tissues, thus being implicated that PPARgamma/PGC-1alpha might play important roles in the pathogenesis and prevention of asthma.

Animals ; Asthma ; chemically induced ; physiopathology ; Glutamate-Cysteine Ligase ; genetics ; metabolism ; Guinea Pigs ; Lung ; metabolism ; Male ; NF-E2-Related Factor 2 ; genetics ; metabolism ; Ovalbumin ; PPAR gamma ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Transcription Factors ; genetics ; metabolism

OBJECTIVETo investigate the role of nuclear factor erythroid 2-related factor 2 (Nrf2) as a key transcription factor of cytoprotection against inflammation in the spinal cord upregulation of matrix metalloproteinase-9 (MMP-9), tumor necrosis factor-α(TNF-α) after spinal cord injury (SCI).

METHODSWild-type Nrf2(+/+) and Nrf2(-/-)-deficient mice were subjected to a murine SCI model induced by the application of vascular clips (force of 10 g) to the dura after a three-level T8-T10 laminectomy. The wet/dry weight ratio was used to reflect the percentage of water content of impaired spinal cord tissue at 48 h after SCI. The mRNA levels of MMP-9 were determined using reverse-transcriptase polymerase chain reaction (RT-PCR), and the protein levels of TNF-α and MMP-9 were detected by enzyme-linked immunosorbent assay at 24 h after SCI. Furthermore, gelatin zymography analysis was used to show MMP-9 activity of spinal cord tissue at 24 h after SCI. Software SPSS 16.0 was used for the statistical analysis.

RESULTSAfter SCI, spinal cord water content, the expression of TNF-α and MMP-9 all increased in both injured Nrf2(+/+) and Nrf2(-/-) mice compared with their respective sham-operated mice. However, Nrf2(-/-) mice were shown to have more severe spinal cord edema, more TNF-α expression, more production and activity of MMP-9 compared with their wild-type Nrf2(+/+) counterparts after SCI (P < 0.05).

CONCLUSIONSThe results suggest that Nrf2 plays an important protective role in limiting the spinal cord upregulation of TNF-α and MMP-9 after SCI. It may be a new therapeutic target of SCI.

Animals ; Disease Models, Animal ; Female ; Genotype ; Male ; Matrix Metalloproteinase 9 ; metabolism ; Mice ; Mice, Inbred ICR ; Mice, Knockout ; NF-E2-Related Factor 2 ; genetics ; Spinal Cord ; metabolism ; Spinal Cord Injuries ; genetics ; metabolism ; Tumor Necrosis Factor-alpha ; metabolism

OBJECTIVETo investigate the effect of tBHQ and sulforaphane on the protein expression in Nrf2-ARE signaling pathway of Caco2 cells.

METHODSHuman colorectal carcinoma Caco2 cells were treated with 20 micromol/L tBHQ and 5 micromol/L sulforaphane (SFN) respectively. Real time PCR, Western blotting and immunoflourescence staining (IF) were performed to measure the target gene expression.

RESULTSNrf2, AKR1C1 and NQO1 protein expressions were increased time-dependently in Caco2 cells after treatment with tBHQ and SFN. Time-course experiments showed that tBHQ and SFN increased the accumulation of Nrf2, and concomitantly increased the protein levels of AKR1C1 and NQO1. Real-time PCR and Western blotting showed that tBHQ and SFN significantly increased the expression of Nrf2 at 8h after the treatment, and AKR1C1 and NQO1 at 16 h. Confocal microscopy technique showed that Nrf2 accumulated in the nucleus at 6-8 h after treatment with tBHQ. After 1 h treatment with tBHQ the nuclear Nrf2 maintained at elevated level for at least 4 h with tBHQ withdrawn.

CONCLUSIONtBHQ and SFN induced nuclear accumulation of Nrf2 and activated Nrf2-dependent regulation of ARE-mediated gene expression in Caco2 cells. In addition, the results provide experimental evidence for choosing the dose and frequency of the inducer in cancer chemoprevention study and in developing inhibitors of Nrf2-ARE signaling pathway.

Anticarcinogenic Agents ; pharmacology ; Antioxidants ; metabolism ; pharmacology ; Caco-2 Cells ; Calcium-Transporting ATPases ; antagonists & inhibitors ; Humans ; Hydroquinones ; pharmacology ; Isothiocyanates ; NF-E2-Related Factor 2 ; genetics ; metabolism ; physiology ; Oxidative Stress ; genetics ; physiology ; Response Elements ; physiology ; Signal Transduction ; drug effects ; Thiocyanates ; pharmacology

Antioxidants ; metabolism ; pharmacology ; Down-Regulation ; Gene Expression Regulation ; Humans ; NF-E2-Related Factor 2 ; genetics ; metabolism ; physiology ; Neoplasms ; genetics ; metabolism ; Oxidative Stress ; genetics ; physiology ; Response Elements ; physiology ; Signal Transduction ; physiology

Gastrointestinal tract carcinoma is one of the leading causes of cancer-related death in China. Chemoprevention has been considered as a potential approach to control this type of disease. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a redox-sensitive transcription factor that protects cells from oxidative/electrophilic stresses by activating the expression of a battery of cytoprotective genes through the antioxidant response element (ARE). Recently, Nrf2 has emerged as a novel target for chemoprevention. Several natural or synthetic chemicals, which activate Nrf2/ARE signaling pathway, have showed effect in animal models, and promises in many ongoing clinical trials. This review summarizes the recent findings on the regulation of Nrf2/ARE signaling pathway, and the developments in both preclinical and clinical studies.
Animals ; Anticarcinogenic Agents ; pharmacology ; Antioxidants ; metabolism ; Chemoprevention ; Digestive System Neoplasms ; genetics ; metabolism ; prevention & control ; Humans ; NF-E2-Related Factor 2 ; genetics ; metabolism ; Oxidative Stress ; drug effects ; Response Elements ; genetics ; Signal Transduction ; drug effects