Lung cancer is one of the most common cancers in the world, and its treatment strategy is mainly surgery combined with radiotherapy and chemotherapy. However, long-term chemotherapy will result in drug resistance, which is also one of the difficulties in the treatment of lung cancer. Ferroptosis is an iron-dependent and lipid peroxidation-driven non-apoptotic cell death cascade, occurring when there is an imbalance of redox homeostasis in the cell. Nuclear factor erythroid 2-related factor 2 (Nrf2) is key for cellular antioxidant responses. Numerous studies suggest that Nrf2 assumes an extremely important role in regulation of ferroptosis, for its various functions in iron, lipid, and amino acid metabolism, and so on. In this review, a brief overview of the research progress of ferroptosis over the past decade will be presented. In particular, the mechanism of ferroptosis and the regulation of ferroptosis by Nrf2 will be discussed, as well as the role of the Nrf2 pathway and ferroptosis in tumor drug resistance, which will provide new research directions for the treatment of drug-resistant lung cancer patients.
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Humans ; Ferroptosis ; NF-E2-Related Factor 2/genetics* ; Lung Neoplasms/genetics* ; Drug Resistance, Neoplasm ; Iron

This study aims to explore the effects of Shenqi Dihuang Decoction on high-glucose induced ferroptosis and the nuclear factor erythroid 2-related factor 2(Nrf2)/heme oxygenase-1(HO-1)/glutathione peroxidase 4(GPX4) axis in human renal tubular epithelial cells(HK-2) and to clarify the underlying mechanism. The cell injury model was established by exposing HK-2 to high glucose, and the Shenqi Dihuang Decoction-medicated serum was prepared. The optimal concentration and intervention time of Shenqi Dihuang Decoction were determined. HK-2 were divided into normal, high glucose, and low-, medium-, and high-dose Shenqi Dihuang Decoction groups. After interventions, the cell proliferation rate in each group was determined and the cell morphology and mitochondrial ultrastructure were observed. Then, the levels of intracellular reactive oxygen species(ROS), ferrous ion(Fe~(2+)), glutathione(GSH), and malondialdehyde(MDA) and the protein levels of Nrf2, HO-1, GPX4, and xCT were measured. The optimal concentration and intervention time of Shenqi Dihuang Decoction-medicated serum were determined to be 10% and 24 h, respectively. Compared with the high glucose group, high-dose Shenqi Dihuang Decoction promoted the proliferation of HK-2. The cells in the low-, medium-, and high-dose Shenqi Dihuang Decoction groups presented tight arrangement, an increased cell count, improved morphology from a spindle-fiber shape to a cobblestone shape, and improved morphology and structure of mitochondrial membrane and cristae, compared with those in the high glucose group. Meanwhile, all the doses of Shenqi Dihuang Decoction inhibited ROS elevation to mitigate the peroxidation damage, lowered the Fe~(2+) and MDA levels and elevated the GSH level to inhibit lipid peroxidation, and activated the antioxidant pathway to upregulate the protein levels of Nrf2, HO-1, xCT, and GPX4. In conclusion, Shenqi Dihuang Decoction-medicated serum can inhibit high-glucose induced ferroptosis of HK-2 in vitro, which involves the antioxidant effect and the activation of the Nrf2/HO-1/GPX4 pathway.
Humans ; Ferroptosis ; NF-E2-Related Factor 2/genetics* ; Reactive Oxygen Species ; Epithelial Cells ; Antioxidants ; Glutathione ; Glucose

This project aimed to explore the protective effect of ginsenoside Rg_1 on hypoxia/reoxygenation(H/R)-induced H9 c2 cardiomyocyte injury and its underlying signaling pathway. The H/R model of H9 c2 cardiomyocytes was established and then the cells were divided into different treatment groups. CCK-8(cell counting kit-8) was used to detect the activity of cardiomyocytes; Brdu assay was used to detect the proliferation of H9 c2 cells; the caspase-3 activity was tested, and then the protein expression was assessed by Western blot. Flow cytometry was used to evaluate the apoptosis level of cardiomyocytes. Ginsenoside Rg_1 inhibited H/R-induced cardiomyocyte apoptosis and caspase-3 activity, promoted nuclear transcription of nuclear factor erythroid-2 related factor 2(Nrf2), and enhanced the expression of the downstream heme oxygenase-1(HO-1). Ginsenoside Rg_1 could increase Nrf2 nuclear transcription and HO-1 expression with the increase of concentration(10, 20, 40, 60 μmol·L~(-1)). However, the protective effect of ginsenoside Rg_1 on cardiomyocytes was significantly weakened after the transfection of Nrf2-siRNA. Ginsenoside Rg_1 could protect cardiomyocytes by activating the Nrf2/HO-1 pathway.
Apoptosis ; Ginsenosides/pharmacology* ; Heme Oxygenase-1/genetics* ; Humans ; Hypoxia ; Myocytes, Cardiac ; NF-E2-Related Factor 2/genetics*

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

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

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

OBJECTIVE: Acute liver failure (ALF) is characterized by severe liver dysfunction, rapid progression and high mortality and is difficult to treat. Studies have found that sulforaphane (SFN), a nuclear factor E2-related factor 2 (NRF2) agonist, has anti-inflammatory, antioxidant and anticancer effects, and has certain protective effects on neurodegenerative diseases, cancer and liver fibrosis. This paper aimed to explore the protective effect of SFN in ALF and it possible mechanisms of action. METHODS: Lipopolysaccharide and D-galactosamine were used to induce liver injury in vitro and in vivo. NRF2 agonist SFN and histone deacetylase 6 (HDAC6) inhibitor ACY1215 were used to observe the protective effect and possible mechanisms of SFN in ALF, respectively. Cell viability, lactate dehydrogenase (LDH), Fe²⁺, glutathione (GSH) and malondialdehyde (MDA) were detected. The expression of HDAC6, NRF2, glutathione peroxidase 4 (GPX4), acyl-CoA synthetase long-chain family member 4 (ACSL4) and solute carrier family 7 member 11 (SLC7A11) were detected by Western blotting and immunofluorescence. RESULTS: Our results show that NRF2 was activated by SFN. LDH, Fe²⁺, MDA and ACSL4 were downregulated, while GSH, GPX4 and SLC7A11 were upregulated by SFN in vitro and in vivo, indicating the inhibitory effect of SFN on ferroptosis. Additionally, HDAC6 expression was decreased in the SFN group, indicating that SFN could downregulate the expression of HDAC6 in ALF. After using the HDAC6 inhibitor, ACY1215, SFN further reduced HDAC6 expression and inhibited ferroptosis, indicating that SFN may inhibit ferroptosis by regulating HDAC6 activity. CONCLUSION SFN has a protective effect on ALF, and the mechanism may include reduction of ferroptosis through the regulation of HDAC6. Please cite this article as: Zhang YQ, Shi CX, Zhang DM, Zhang LY, Wang LW, Gong ZJ. Sulforaphane, an NRF2 agonist, alleviates ferroptosis in acute liver failure by regulating HDAC6 activity. J Integr Med. 2023; 21(5): 464-473.
Humans ; Ferroptosis ; NF-E2-Related Factor 2/genetics* ; Liver Failure, Acute/drug therapy* ; Isothiocyanates/pharmacology* ; Glutathione ; Histone Deacetylase 6

Asian Continental Ancestry Group ; genetics ; Case-Control Studies ; Genetic Predisposition to Disease ; Hearing Loss, Noise-Induced ; genetics ; Humans ; NF-E2-Related Factor 2 ; genetics ; Occupational Exposure

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