Ivacaftor attenuates gentamicin-induced ototoxicity through the CFTR-Nrf2-HO1/NQO1 pathway.

OBJECTIVES: Gentamicin is one of the most common ototoxic drugs that can lower patients' quality of life. Oxidative stress is a key factors inducing sensory hair cell death during gentamicin administration. So far, there are no effective drugs to prevent or treat gentamicin- induced hearing loss. A recent study found cystic fibrosis transmembrane conductance regulator (CFTR) as a new target to modulate cellular oxidative balance. The objective of this study was to estimate the effect of the CFTR activator ivacaftor on gentamicin-induced ototoxicity and determine its mechanism. METHODS: The hair cell count was analyzed by Myosin 7a staining. Apoptosis was analyzed by TUNEL Apoptosis Kit. Cellular reactive oxygen species (ROS) level was detected by DCFH-DA probes. The Nrf2 related proteins expression levels were analyzed by western blot. RESULTS: An in vitro cochlear explant model showed that gentamicin caused ROS accumulation in sensory hair cells and induced apoptosis, and this effect was alleviated by pretreatment with ivacaftor. Western blotting showed that ivacaftor administration markedly increased the protein expression of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO1), and NAD(P)H:quinone oxidoreductase 1 (NQO1). The protective effect of ivacaftor was abolished by the Nrf2 inhibitor ML385. DISCUSSION: Our results indicate the protective role of the CFTR-Nrf2-HO1/NQO1 pathway in gentamicin-induced ototoxicity. Ivacaftor may be repositioned or repurposed towards aminoglycosides-induced hearing loss.

A Secreted BBE-Like Enzyme Acting as a Drug-Binding Efflux Carrier Confers Microbial Self-Resistance to Mitomycin C.

The berberine bridge enzyme (BBE)-like flavoproteins have attracted continuous attention for their capability to catalyze various oxidative reactions. Here we demonstrate that MitR, a secreted BBE-like enzyme, functions as a special drug-binding efflux protein evolved from quinone reductase. Moreover, this protein provides self-resistance to its hosts toward the DNA-alkylating agent mitomycin C with a distinctive strategy, featured by independently performing drug binding and efflux.

Genetic variants affecting NQO1 protein levels impact the efficacy of idebenone treatment in Leber hereditary optic neuropathy.

Idebenone, the only approved treatment for Leber hereditary optic neuropathy (LHON), promotes recovery of visual function in up to 50% of patients, but we can neither predict nor understand the non-responders. Idebenone is reduced by the cytosolic NAD(P)H oxidoreductase I (NQO1) and directly shuttles electrons to respiratory complex III, bypassing complex I affected in LHON. We show here that two polymorphic variants drastically reduce NQO1 protein levels when homozygous or compound heterozygous. This hampers idebenone reduction. In its oxidized form, idebenone inhibits complex I, decreasing respiratory function in cells. By retrospectively analyzing a large cohort of idebenone-treated LHON patients, classified by their response to therapy, we show that patients with homozygous or compound heterozygous NQO1 variants have the poorest therapy response, particularly if carrying the m.3460G>A/MT-ND1 LHON mutation. These results suggest consideration of patient NQO1 genotype and mitochondrial DNA mutation in the context of idebenone therapy.

Impact of NQO1 dysregulation in CNS disorders.

NAD(P)H Quinone Dehydrogenase 1 (NQO1) plays a pivotal role in the regulation of neuronal function and synaptic plasticity, cellular adaptation to oxidative stress, neuroinflammatory and degenerative processes, and tumorigenesis in the central nervous system (CNS). Impairment of the NQO1 activity in the CNS can result in abnormal neurotransmitter release and clearance, increased oxidative stress, and aggravated cellular injury/death. Furthermore, it can cause disturbances in neural circuit function and synaptic neurotransmission. The abnormalities of NQO1 enzyme activity have been linked to the pathophysiological mechanisms of multiple neurological disorders, including Parkinson's disease, Alzheimer's disease, epilepsy, multiple sclerosis, cerebrovascular disease, traumatic brain injury, and brain malignancy. NQO1 contributes to various dimensions of tumorigenesis and treatment response in various brain tumors. The precise mechanisms through which abnormalities in NQO1 function contribute to these neurological disorders continue to be a subject of ongoing research. Building upon the existing knowledge, the present study reviews current investigations describing the role of NQO1 dysregulations in various neurological disorders. This study emphasizes the potential of NQO1 as a biomarker in diagnostic and prognostic approaches, as well as its suitability as a target for drug development strategies in neurological disorders.

NQO1 Mediates Lenvatinib Resistance by Regulating ROS-induced Apoptosis in Hepatocellular Carcinoma.

OBJECTIVE: Hepatocellular carcinoma (HCC) is the third leading cause of cancer-associated death worldwide. As a first-line drug for advanced HCC treatment, lenvatinib faces a significant hurdle due to the development of both intrinsic and acquired resistance among patients, and the underlying mechanism remains largely unknown. The present study aims to identify the pivotal gene responsible for lenvatinib resistance in HCC, explore the potential molecular mechanism, and propose combinatorial therapeutic targets for HCC management. METHODS: Cell viability and colony formation assays were conducted to evaluate the sensitivity of cells to lenvatinib and dicoumarol. RNA-Seq was used to determine the differences in transcriptome between parental cells and lenvatinib-resistant (LR) cells. The upregulated genes were analyzed by GO and KEGG analyses. Then, qPCR and Western blotting were employed to determine the relative gene expression levels. Afterwards, the intracellular reactive oxygen species (ROS) and apoptosis were detected by flow cytometry. RESULTS: PLC-LR and Hep3B-LR were established. There was a total of 116 significantly upregulated genes common to both LR cell lines. The GO and KEGG analyses indicated that these genes were involved in oxidoreductase and dehydrogenase activities, and reactive oxygen species pathways. Notably, NAD(P)H:quinone oxidoreductase 1 (NQO1) was highly expressed in LR cells, and was involved in the lenvatinib resistance. The high expression of NQO1 decreased the production of ROS induced by lenvatinib, and subsequently suppressed the apoptosis. The combination of lenvatinib and NQO1 inhibitor, dicoumarol, reversed the resistance of LR cells. CONCLUSION: The high NQO1 expression in HCC cells impedes the lenvatinib-induced apoptosis by regulating the ROS levels, thereby promoting lenvatinib resistance in HCC cells.

SeMet alleviates AFB1-induced oxidative stress and apoptosis in rabbit kidney by regulating Nrf2//Keap1/NQO1 and PI3K/AKT signaling pathways.

The purpose of this study was to explore the protective effect of SeMet on renal injury induced by AFB1 in rabbits and its molecular mechanism. Forty rabbits of 35 days old were randomly divided into control group, AFB1 group (0.3 mg AFB1/kg b.w), 0.2 mg/kg Se + AFB1 group (0.3 mg AFB1/kg b.w + 0.2 mg SeMet/kg feed) and 0.4 mg/kg Se + AFB1 group (0.3 mg AFB1/kg b.w + 0.4 mg SeMet/kg feed). The SeMet treatment group was fed different doses of SeMet diets every day for 21 days. On the 17-21 day, the AFB1 treatment group, the 0.2 mg/kg Se + AFB1 group and the 0.4 mg/kg Se + AFB1 group were administered 0.3 mg AFB1 /kg b.w by gavage (dissolved in 0.5 ml olive oil) respectively. The results showed that AFB1 poisoning resulted in the changes of renal structure, the increase of renal coefficient and serum biochemical indexes, the ascent of ROS and MDA levels, the descent of antioxidant enzyme activity, and the significant down-regulation of Nrf2, HO-1 and NQO1. Besides, AFB1 poisoning increased the number of renal apoptotic cells, rised the levels of PTEN, Bax, Caspase-3 and Caspase-9, and decreased the levels of PI3K, AKT, p-AKT and Bcl-2. In summary, SeMet was added to alleviate the oxidative stress injury and apoptosis of kidney induced by AFB1, and the effect of 0.2 mg/kg Se + AFB1 is better than 0.4 mg/kg Se + AFB1.

Distinct oligomerization and NADPH binding modes observed between L. donovani and human quinone oxidoreductases.

Electron-driven process helps the living organism in the generations of energy, biomass production and detoxification of synthetic compounds. Soluble quinone oxidoreductases (QORs) mediate the transfer of an electron from NADPH to various quinone and other compounds, helping in the detoxification of quinones. QORs play a crucial role in cellular metabolism and are thus potential targets for drug development. Here we report the crystal structure of the NADPH-dependent QOR from Leishmania donovani (LdQOR) at 2.05 Å. The enzyme exists as a homo-dimer, with each protomer consisting of two domains, responsible for binding NADPH cofactor and the substrate. Interestingly, the human QOR exists as a tetramer. Comparative analysis of the oligomeric interfaces of LdQOR with HsQOR shows no significant differences in the protomer/dimer assembly. The tetrameric interface of HsQOR is stabilized by salt bridges formed between Arg 169 and Glu 271 which is non-existent in LdQOR, with an Alanine replacing the glutamate. This distinct feature is conserved across other dimeric QORs, indicating the importance of this interaction for tetramer association. Among the homologs, the sequences of the loop region involved in the stabilization and binding of the adenine ring of the NADPH shows significant differences except for an Arginine & glycine residues. In dimer QORs, this Arginine acts as a gate to the co-factor, while the NADPH binding mode in the human homolog is distinct, stabilized by His 200 and Asn 229, which are not conserved in LdQOR. These distinct features have the potential to be utilized for therapeutic interventions.

Combined exposure to manganese and iron decreases oxidative stress-induced nerve damage by increasing Nrf2/HO-1/NQO1 expression.

BACKGROUND: Manganese (Mn) and iron (Fe) are essential trace elements for humans, yet excessive exposure to Mn or Fe can accumulate in the central nervous system (CNS) and cause neurotoxicity. The purpose of this study was to investigate the effects of Mn and Fe exposure, alone or in combination, on inducing oxidative stress-induced neurological damage in rat cortical and SH-SY5Y cells, and to determine whether combined exposure to these metals increases their individual toxicity. METHODS: SH-SY5Y cells and male Sprague-Dawley rats were used to observe the effects of oxidative stress-induced neurological damage induced by exposure to manganese and iron alone or in combination. To detect the expression of anti-oxidative stress-related proteins, Nrf2, HO-1, and NQO1, and the apoptosis-related proteins, Bcl2 and Bax, and the neurological damage-related protein, α-syn. To detect reactive oxygen species generation and apoptosis. To detect the expression of the rat cortical protein Nrf2. To detect the production of proinflammatory cytokines. RESULTS: We demonstrate that juvenile developmental exposure to Mn and Fe and their combination impairs cognitive performance in rats by inducing oxidative stress causing neurodegeneration in the cortex. Mn, Fe, and their combined exposure increased the expression of ROS, Bcl2, Bax, and α-syn, activated the inflammatory factors IL-6 and IL-12, inhibited the activities of SOD and GSH, and induced oxidative stress-induced neurodegeneration both in rats and SH-SY5Y cells. Combined Mn-Fe exposure attenuated the oxidative stress induced by Mn and Fe exposure alone by increasing the expression of antioxidant factors Nrf2, HO-1, and NQO1. CONCLUSION: In both in vivo and in vitro studies, manganese and iron alone or in combination induced oxidative stress, leading to neuronal damage. In contrast, combined exposure to manganese and iron mitigated the oxidative stress induced by exposure to manganese and iron alone by increasing the expression of antioxidant factors. Therefore, studies to elucidate the main causes of toxicity and establish the molecular mechanisms of toxicity should help to develop more effective therapeutic modalities in the future.

Discovery and Mechanistic Elucidation of NQO1-Bioactivatable Small Molecules That Overcome Resistance to Degraders.

Degraders hold the promise to efficiently inactivate previously intractable disease-relevant targets. Unlike traditional inhibitors, degraders act substoichiometrically and rely on the hijacked proteolysis machinery, which can also act as an entry point for resistance. To fully harness the potential of targeted protein degradation, it is crucial to comprehend resistance mechanisms and formulate effective strategies to overcome them. We conducted a chemical screening to identify synthetic lethal vulnerabilities of cancer cells that exhibit widespread resistance to degraders. Comparative profiling followed by tailored optimization delivered the small molecule RBS-10, which shows preferential cytotoxicity against cells pan-resistant to degraders. Multiomics deconvolution of the mechanism of action revealed that RBS-10 acts as a prodrug bioactivated by the oxidoreductase enzyme NQO1, which is highly overexpressed in our resistance models. Collectively, our work informs on NQO1 as an actionable vulnerability to overcome resistance to degraders and as a biomarker to selectively exploit bioactivatable prodrugs in cancer.

NAD(P)H:quinone Oxidoreductase 1 Is Involved in AZ-1-induced Apoptotic Effects in Nasopharyngeal Carcinoma TW01 Cells.

BACKGROUND/AIM: Current NPC treatment methods have improved the 5-year survival rates of patients; however, some patients do not benefit from the treatments. Therefore, the existing treatment methods or new drugs must be developed to improve the patient's prognosis. NAD (P)H:quinone oxidoreductase 1 (NQO1), an electron reductase highly expressed in various cancers, can convert aziridinyl-substituted quinone-derived compound into an alkylating agent, resulting in cell apoptosis. Therefore, a di-aziridinyl-substituted quinone-derived compound, AZ-1, was designed previously. The present study investigated whether AZ-1 has anticancer activities in NPC cells and explored the underlying mechanism. MATERIALS AND METHODS: NPC-TW01 cells were used in the study, and 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide, colony formation, terminal deoxynucleotidyl transferase dUTP nick end labeling, and immunoblotting assays were performed to assess the cell viability, cell survival, DNA fragmentation, and protein expression, respectively. RESULTS: The results show that AZ-1 significantly inhibited the viability and survival of NPC-TW01 cells. AZ-1 also induced the expression of cleaved PARP, cleaved caspase-8, cleaved caspase-9, and cleaved caspase-3, and triggered DNA fragmentation in NPC-TW01 cells. In addition, AZ-1 induced γH2AX expression, a DNA damage marker, in NPC-TW01 cells. Treatment with dicoumarol, an NQO1 activity inhibitor, not only reversed AZ-1-induced cell viability inhibition but also decreased AZ-1-induced expression of γH2AX, cleaved caspase-8, cleaved caspase-9, and cleaved caspase-3. CONCLUSION: NQO1 reverses AZ-1-triggered cell viability inhibition, DNA damage, and apoptosis. The findings of this study may provide a basis for the possible clinical application of AZ-1 in the treatment of NPC to improve the prognosis of patients with NPC.

The Candida albicans ζ-crystallin homolog Zta1 promotes resistance to oxidative stress.

IMPORTANCE: Candida albicans is an important human pathogen that can cause lethal systemic infections. The ability of C. albicans to colonize and establish infections is closely tied to its highly adaptable nature and capacity to resist various types of stress, including oxidative stress. Previous studies showed that four C. albicans proteins belonging to the flavodoxin-like protein family of quinone reductases are needed for resistance to quinones and virulence. Therefore, in this study, we examined the role of a distinct type of quinone reductase, Zta1, and found that it acts in conjunction with the flavodoxin-like proteins to protect against oxidative stress.

ß-lapachone regulates mammalian inositol pyrophosphate levels in an NQO1- and oxygen-dependent manner.

Inositol pyrophosphates (PP-InsPs) are energetic signaling molecules with important functions in mammals. As their biosynthesis depends on ATP concentration, PP-InsPs are tightly connected to cellular energy homeostasis. Consequently, an increasing number of studies involve PP-InsPs in metabolic disorders, such as type 2 diabetes, aspects of tumorigenesis, and hyperphosphatemia. Research conducted in yeast suggests that the PP-InsP pathway is activated in response to reactive oxygen species (ROS). However, the precise modulation of PP-InsPs during cellular ROS signaling is unknown. Here, we report how mammalian PP-InsP levels are changing during exposure to exogenous (H2O2) and endogenous ROS. Using capillary electrophoresis electrospray ionization mass spectrometry (CE-ESI-MS), we found that PP-InsP levels decrease upon exposure to oxidative stressors in HCT116 cells. Application of quinone drugs, particularly ß-lapachone (ß-lap), under normoxic and hypoxic conditions enabled us to produce ROS in cellulo and to show that ß-lap treatment caused PP-InsP changes that are oxygen-dependent. Experiments in MDA-MB-231 breast cancer cells deficient of NAD(P)H:quinone oxidoreductase-1 (NQO1) demonstrated that ß-lap requires NQO1 bioactivation to regulate the cellular metabolism of PP-InsPs. Critically, significant reductions in cellular ATP concentrations were not directly mirrored in reduced PP-InsP levels as shown in NQO1-deficient MDA-MB-231 cells treated with ß-lap. The data presented here unveil unique aspects of ß-lap pharmacology and its impact on PP-InsP levels. The identification of different quinone drugs as modulators of PP-InsP synthesis will allow the overall impact on cellular function of such drugs to be better appreciated.

Heterocyclic Iminoquinones and Quinones from the National Cancer Institute (NCI, USA) COMPARE Analysis.

This review uses the National Cancer Institute (NCI) COMPARE program to establish an extensive list of heterocyclic iminoquinones and quinones with similarities in differential growth inhibition patterns across the 60-cell line panel of the NCI Developmental Therapeutics Program (DTP). Many natural products and synthetic analogues are revealed as potential NAD(P)H:quinone oxidoreductase 1 (NQO1) substrates, through correlations to dipyridoimidazo[5,4-f]benzimidazoleiminoquinone (DPIQ), and as potential thioredoxin reductase (TrxR) inhibitors, through correlations to benzo[1,2,4]triazin-7-ones and pleurotin. The strong correlation to NQO1 infers the enzyme has a major influence on the amount of the active compound with benzo[e]perimidines, phenoxazinones, benz[f]pyrido[1,2-a]indole-6,11-quinones, seriniquinones, kalasinamide, indolequinones, and furano[2,3-b]naphthoquinones, hypothesised as prodrugs. Compounds with very strong correlations to known TrxR inhibitors had inverse correlations to the expression of both reductase enzymes, NQO1 and TrxR, including naphtho[2,3-b][1,4]oxazepane-6,11-diones, benzo[a]carbazole-1,4-diones, pyranonaphthoquinones (including kalafungin, nanaomycin A, and analogues of griseusin A), and discorhabdin C. Quinoline-5,8-dione scaffolds based on streptonigrin and lavendamycin can correlate to either reductase. Inhibitors of TrxR are not necessarily (imino)quinones, e.g., parthenolides, while oxidising moieties are essential for correlations to NQO1, as with the mitosenes. Herein, an overview of synthetic methods and biological activity of each family of heterocyclic imino(quinone) is provided.

NAD(P)H:Quinone Acceptor Oxidoreductase 1 (NQO1) Activatable Salicylamide H+ /Cl- Transporters.

NAD(P)H:quinone acceptor oxidoreductase 1 (NQO1), a detoxifying enzyme overexpressed in tumors, plays a key role in protecting cancer cells against oxidative stress and thus has been considered an attractive candidate for activating prodrug(s). Herein, we report the first use of NQO1 for the selective activation of 'protransporter' systems in cancer cells leading to the induction of apoptosis. Salicylamides, easily synthesizable small molecules, have been effectively used for efficient H+ /Cl- symport across lipid membranes. The ion transport activity of salicylamides was efficiently abated by caging the OH group with NQO1 activatable quinones via either ether or ester linkage. The release of active transporters, following the reduction of quinone caged 'protransporters' by NQO1, was verified. Both the transporters and protransporters exhibited significant toxicity towards the MCF-7 breast cancer line, mediated via the induction of oxidative stress, mitochondrial membrane depolarization, and lysosomal deacidification. Induction of cell death via intrinsic apoptotic pathway was verified by monitoring PARP1 cleavage.

MiR-766-3p and miR-671-5p attenuate aristolochic acid-induced hepatotoxicity by directly targeting the key bioactivating enzyme NQO1.

Aristolochic acid (AA) as an emerging contaminant in herbal medicines or crops has been well-recognized for causing nephropathy since 1990s. Over the last decade, mounting evidence has linked AA to liver injury; however, the underlying mechanism is poorly elucidated. MicroRNAs respond to environmental stress and mediate multiple biological processes, thus showing biomarker potentials prognostically or diagnostically. In the present study, we investigated the role of miRNAs in AA-induced hepatotoxicity, specifically in regulating NQO1, the key enzyme responsible for AA bioactivation. In silico analysis showed that hsa-miR-766-3p and hsa-miR-671-5p were significantly associated with AAI exposure as well as NQO1 induction. A 28-day rat experiment of 20 mg/kg AA exposure demonstrated a 3-fold increase of NQO1 and an almost 50 % decrease of the homologous miR-671 that were accompanied with liver injury, which was consistent with in silico prediction. Further mechanistic investigation using Huh7 cells with IC50 of AAI at 146.5 µM showed both hsa-miR-766-3p and hsa-miR-671-5p were able to directly bind to and down-regulate NQO1 basal expression. In addition, both miRNAs were shown to suppress AAI-induced NQO1 upregulation in Huh7 cells at a cytotoxic concentration of 70 µM, and consequently alleviate AAI-induced cellular effects, including cytotoxicity and oxidative stress. Together, these data illustrate that miR-766-3p and miR-671-5p attenuate AAI-induced hepatotoxicity, and thus have monitoring and diagnostic potentials.

Fighting drug-resistant lung cancer by induction of NAD(P)H:quinone oxidoreductase 1 (NQO1)-mediated ferroptosis.

Drug resistance is a major challenge in cancer treatment. The substrates of NAD(P)H:quinone oxidoreductase 1 (NQO1) show a promising anticancer effect in clinical trials. We previously identified a natural NQO1 substrate 2-methoxy-6-acetyl-7-methyljuglone (MAM) with a potent anticancer effect. The present study was designed to explore the efficacy of MAM in fighting against drug-resistant non-small cell lung cancer (NSCLC). The anticancer effect of MAM was evaluated in cisplatin-resistant A549 and AZD9291-resistant H1975 cells. The interaction of MAM with NQO1 was measured by cellular thermal shift assay and drug affinity responsive target stability assay. The NQO1 activity and expression were measured using NQO1 recombinant protein, Western blotting, and immunofluorescence staining assay. The roles of NQO1 were examined by NQO1 inhibitor, small interfering RNA (siRNA), and short hairpin RNA (shRNA). The roles of reactive oxygen species (ROS), labile iron pool (LIP), and lipid peroxidation were determined. MAM induced significant cell death in drug-resistant cells with similar potency to that of parental cells, which were completely abolished by NQO1 inhibitor, NQO1 siRNA, and iron chelators. MAM activates and binds to NQO1, which triggers ROS generation, LIP increase, and lipid peroxidation. MAM significantly suppressed tumor growth in the tumor xenograft zebrafish model. These results showed that MAM induced ferroptosis by targeting NQO1 in drug-resistant NSCLC cells. Our findings provided a novel therapeutic strategy for fighting against drug resistance by induction of NQO1-mediated ferroptosis.

NQO1 alleviates renal fibrosis by inhibiting the TLR4/NF-κB and TGF-ß/Smad signaling pathways in diabetic nephropathy.

OBJECTIVE: Diabetic nephropathy (DN) is one of the main complications of diabetes, and inflammation and fibrosis play an important role in its progression. NAD(P)H: quinone oxidoreductase 1 (NQO1) protects cells from oxidative stress and damage caused by toxic quinones. In the present study, we aimed to investigate the protective effects of NQO1 against diabetes-induced renal inflammation and fibrosis and the underlying mechanisms. METHODS: In vivo, the kidneys of type 2 diabetes model db/db mice were infected with adeno-associated virus vectors to induce NQO1 overexpression. In vitro, human renal tubular epithelial (HK-2) cells transfected with NQO1 pcDNA3.1(+) were cultured under high-glucose (HG) conditions. Gene and protein expression was assessed by quantitative real-time PCR, Western blotting, immunofluorescence, and immunohistochemical staining. Mitochondrial reactive oxygen species (ROS) were detected with MitoSOX Red. RESULT: Our study revealed that the expression of NQO1 was markedly downregulated and that Toll-like receptor (TLR)4 and TGF-ß1 expression was upregulated in vivo and in vitro under diabetic conditions. Overexpression of NQO1 suppressed proinflammatory cytokine (IL-6, TNF-α, MCP-1) secretion, extracellular matrix (ECM) (collagen IV, fibronectin) accumulation and epithelial-mesenchymal transition (EMT) (α-SMA, E-cadherin) in the db/db mouse kidneys and HG-cultured HK-2 cells. Furthermore, NQO1 overexpression ameliorated HG-induced TLR4/NF-κB and TGF-ß/Smad pathways activation. Mechanistic studies demonstrated that a TLR4 inhibitor (TAK-242) suppressed the TLR4/NF-κB signaling pathway, proinflammatory cytokine secretion, EMT and ECM-related protein expression in HG-exposed HK-2 cells. In addition, we found that the antioxidants N-acetylcysteine (NAC) and tempol increased the expression of NQO1 and decreased the expression of TLR4, TGF-ß1, Nox1, and Nox4 and ROS production in HK-2 cells cultured under HG conditions. CONCLUSIONS: These data suggest that NQO1 alleviates diabetes-induced renal inflammation and fibrosis by regulating the TLR4/NF-κB and TGF-ß/Smad signaling pathways.

Glycyrrhizin protects against particulate matter-induced lung injury via regulation of endoplasmic reticulum stress and NLRP3 inflammasome-mediated pyroptosis through Nrf2/HO-1/NQO1 signaling pathway.

Particulate matter (PM) is a major environmental pollutant that contributes considerably to deaths worldwide. The pathogenesis of PM-induced lung injury (PILI) is far from elucidated and warrants effective intervention. An effective component of licorice, glycyrrhizin (GL), has been the subject of much research due to its anti-inflammatory and anti-oxidative capabilities. Although preventive properties of GL are well-known, the precise mechanism of GL in PILI has not yet been investigated. A mouse model of PILI was used to examine the protective effects of GL in vivo, and a human bronchial epithelial cells (HBECs) model was used in vitro. In order to determine whether GL mitigates PILI, its effects on endoplasmic reticulum (ER) stress, NLRP3 inflammasome-mediated pyroptosis and the oxidative response were examined. According to the findings, GL reduced PILI and activate anti-oxidative Nrf2/HO-1/NQO1 signaling in mice. Notably, the effect of GL on PM-induced ER stress and NLRP3 inflammasome-mediated pyroptosis was significantly attenuated by the Nrf2 inhibitor ML385. The data suggest that via the anti-oxidative Nrf2 signaling, GL may reduce oxidative stress-mediated ER stress and NLRP3 inflammasome-mediated pyroptosis. Therefore, GL may serve as a promising treatment for PILI.

Eriodictyol regulated ferroptosis, mitochondrial dysfunction, and cell viability via Nrf2/HO-1/NQO1 signaling pathway in ovarian cancer cells.

This study aimed to investigate the antitumor effect and the underlying molecular mechanism of eriodictyol on ovarian cancer cells. CaoV3 and A2780 were exposed to eriodictyol at different concentrations of 0-800 µM. Cell apoptosis and viability were determined by TdT-mediated dUTP Nick-End Labeling (TUNEL) assay and Cell Counting Kit-8 (CCK-8) assay, respectively. Mitochondrial membrane potential was evaluated by flow cytometers with a JC-1 detection kit. Fe2+ content was evaluated using an iron assay kit. The section of tumor tissues was observed using hematoxylin-eosin (H&E) staining and nuclear factor erythroid 2-related factor 2 (Nrf2) expression was detected by immunohistochemistry (IHC) staining. Eriodictyol suppressed cell viability and induced cell apoptosis of CaoV3 and A2780 cells. Half maximal inhibitory concentration (IC50 ) value of CaoV3 at 24 and 48 h was (229.74 ± 5.13) µM and (38.44 ± 4.68) µM, and IC50 value of A2780 at 24 and 48 h was (248.32 ± 2.54) µM and (64.28 ± 3.19) µM. Fe2+ content and reactive oxygen species production were increased and protein levels of SLC7A11 and GPX4 were decreased by eriodictyol. Besides, eriodictyol reduced the ratio of JC-1 fluorescence ratio, glutathione and malondialdehyde contents but elevated Cytochrome C level. Nrf2 phosphorylation were obviously downregulated by eriodictyol. Finally, eriodictyol suppressed tumor growth, aggravated mitochondrial dysfunction and downregulated Nrf2 expression in tumor tissue in mice. Eriodictyol regulated ferroptosis, mitochondrial dysfunction and cell viability via Nrf2/HO-1/NQO1 signaling pathway in ovarian cancer.