Role of Natural and Synthetic Compounds in Modulating NRF2/KEAP1 Signaling Pathway in Prostate Cancer

The role of nuclear factor erythroid 2-related factor 2 (NRF2) in arsenic toxicity

Arsenic, a naturally occurring toxic element, manifests in various chemical forms and is widespread in the environment. Exposure to arsenic is a well-established risk factor for an elevated incidence of various cancers and chronic diseases. The crux of arsenic-mediated toxicity lies in its ability to induce oxidative stress, characterized by an unsettling imbalance between oxidants and antioxidants, accompanied by the rampant generation of reactive oxygen species and free radicals. In response to this oxidative turmoil, cells deploy their defense mechanisms, prominently featuring the redox-sensitive transcription factor known as nuclear factor erythroid 2-related factor 2 (NRF2). NRF2 stands as a primary guardian against the oxidative harm wrought by arsenic. When oxidative stress activates NRF2, it orchestrates a symphony of downstream antioxidant genes, leading to the activation of pivotal antioxidant enzymes like glutathione-S-transferase, heme oxygenase-1, and NAD(P)H: quinone oxidoreductase 1. This comprehensive review embarks on the intricate and diverse ways by which various arsenicals influence the NRF2 antioxidant pathway and its downstream targets, shedding light on their roles in defending against arsenic exposure toxic effects. It offers valuable insights into targeting NRF2 as a strategy for safeguarding against or treating the harmful and carcinogenic consequences of arsenic exposure.

Nuclear factor erythroid 2-related factor 2 (Nrf2) signaling in heavy metals-induced oxidative stress

Organisms encounter reactive oxidants through intrinsic metabolism and environmental exposure to toxicants. Reactive oxygen and nitrogen species (ROS, RNS) are generally considered detrimental because they induce oxidative stress. In order to combat oxidative stress, a potential modulator of cellular defense nuclear factor erythroid 2-related factor 2 (Nrf2) and its endogenous inhibitor Kelch-like ECH-associated protein 1 (Keap1) operate as a common, genetically preserved intrinsic defense system. There has been a significant increase in the amount of harmful metalloids and metals that individuals are exposed to through their food, water, and air, primarily due to human activities. Many studies have looked at the connection between the emergence of different ailments in humans and ecological exposure to metalloids, i.e., arsenic (As) and metals viz., chromium (Cr), mercury (Hg), cadmium (Cd), cobalt (Co), and lead (Pb). It is known that they can produce ROS in several organs by both direct and indirect means. Studies suggest that Nrf2 signaling is a crucial mechanism in maintaining antioxidant balance and can have two roles, depending on the particular biological setting. From one perspective, Nrf2 is an essential defense mechanism against metal-induced toxicity. Still, it may also operate as a catalyst for metal-induced carcinogenesis in situations involving protracted exposure and persistent activation. Therefore, this review aims to provide an overview of the antioxidant defense mechanism of Nrf2-Keap1 signaling and the interrelation between Nrf2 signaling and the toxic elements.

Nrf2: A critical participant in regulation of apoptosis, ferroptosis, and autophagy in gastric cancer

Nuclear factor erythroid 2-related factor-2 (Nrf2) is a specific transcription factor that maintains redox homeostasis by regulating the expression of anti-oxidative stress-related genes. Hyperactivation of Nrf2 is involved in tumor progression and is associated with chemoresistance in a large number of solid tumors. Programmatic cell death (PCD), such as apoptosis, ferroptosis, and autophagy, plays a crucial role in tumor development and chemotherapy sensitivity. Accumulating evidence suggests that some anti-tumor compounds and genes can induce massive production of reactive oxygen species (ROS) via inhibiting Nrf2 expression, which exacerbates oxidative stress and promotes Gastric cancer (GC) cell death, thereby enhancing the sensitivity of GC cells to chemotherapy-induced PCD. In this review, we summarize the role of antitumor drugs in interfering in three different types of PCD (apoptosis, ferroptosis, and autophagy) in GC cells by modulating Nrf2 expression, as well as the molecular mechanisms through which targeting Nrf2 brings about PCD and chemosensitivity. It is reasonable to believe that Nrf2 serves as a potential therapeutic target, and targeting Nrf2 by drug or gene regulation could provide a new strategy for the treatment of GC.

Vitexin Mitigates Haloperidol-Induced Orofacial Dyskinesia in Rats through Activation of the Nrf2 Pathway

Vitexin (VTX), a C-glycosylated flavone found in various medicinal herbs, is known for its antioxidant, anti-inflammatory, and neuroprotective properties. This study investigated the protective effects of VTX against orofacial dyskinesia (OD) in rats, induced by haloperidol (HPD), along with the neuroprotective mechanisms underlying these effects. OD was induced by administering HPD (1 mg/kg i.p.) to rats for 21 days, which led to an increase in the frequency of vacuous chewing movements (VCMs) and tongue protrusion (TP). VTX (10 and 30 mg/kg) was given intraperitoneally 60 min after each HPD injection during the same period. On the 21st day, following assessments of OD, the rats were sacrificed, and nitrosative and oxidative stress, antioxidant capacity, mitochondrial function, neuroinflammation, and apoptosis markers in the striatum were measured. HPD effectively induced OD, while VTX significantly reduced HPD-induced OD, decreased oxidative stress, enhanced antioxidant capacity, prevented mitochondrial dysfunction, and reduced neuroinflammatory and apoptotic markers in the striatum, and the protective effects of VTX on both behavioral and biochemical aspects of HPD-induced OD were significantly reduced when trigonelline (TGN), an inhibitor of the nuclear factor erythroid-2-related factor 2 (Nrf2)-mediated pathway, was administered. These findings suggest that VTX provides neuroprotection against HPD-induced OD, potentially through the Nrf2 pathway, indicating its potential as a therapeutic candidate for the prevention or treatment of tardive dyskinesia (TD) in clinical settings. However, further detailed research is required to confirm these preclinical findings and fully elucidate VTX's therapeutic potential in human studies.

Physcion Mitigates LPS-Induced Neuroinflammation, Oxidative Stress, and Memory Impairments via TLR-4/NF-кB Signaling in Adult Mice

Alzheimer's disease (AD) is the most predominant cause of dementia, considered a progressive decline in cognitive function that ultimately leads to death. AD has posed a substantial challenge in the records of medical science over the past century, representing a predominant etiology of dementia with a high prevalence rate. Neuroinflammation is a common characteristic of various central nervous system (CNS) pathologies like AD, primarily mediated by specialized brain immune and inflammatory cells, such as astrocytes and microglia. The present study aims to elucidate the potential mechanism of physcion that mitigates LPS-induced gliosis and assesses oxidative stress in mice. Physcion reduced the reactivity of Iba-1- and GFAP-positive cells and decreased the level of inflammatory cytokines like TNF-α and IL-1β. Physcion also reversed the effect of LPS-induced oxidative stress by upregulating the expression of Nrf2 and HO-1. Moreover, physcion treatment reversed LPS-induced synaptic disorder by increasing the level of presynaptic protein SNAP-23 and postsynaptic protein PSD-95. Our findings may provide a contemporary theoretical framework for clinical investigations aimed at examining the pathogenic mechanisms and therapeutic approaches for neuroinflammation and AD.

Marine anticancer drugs in modulating miRNAs and antioxidant signaling

Several marine drugs exert anticancer effects by inducing oxidative stress, which becomes overloaded and kills cancer cells when redox homeostasis is imbalanced. The downregulation of antioxidant signaling induces oxidative stress, while its upregulation attenuates oxidative stress. Marine drugs have miRNA-modulating effects against cancer cells. However, the potential antioxidant targets of such drugs have been rarely explored. This review aims to categorize the marine-drug-modulated miRNAs that downregulate their antioxidant targets, causing oxidative stress in anticancer treatments. We also categorize the downregulation of oxidative-stress-inducing miRNAs in antioxidant protection among non-cancer cells. We summarize the putative antioxidant targets of miRNA-modulating marine drugs by introducing a bioinformatics tool (miRDB). Finally, the marine drugs affecting antioxidant targets are surveyed. In this way, the connections between marine drugs and their modulating miRNA and antioxidant targets are innovatively categorized to provide a precise network for exploring their potential anticancer functions and protective effects on non-cancer cells.

Citrus Flavanone Effects on the Nrf2-Keap1/GSK3/NF-κB/NLRP3 Regulation and Corticotroph-Stress Hormone Loop in the Old Pituitary

Oxidative stress and inflammation are significant causes of aging. At the same time, citrus flavanones, naringenin (NAR), and hesperetin (HES) are bioactives with proven antioxidant and anti-inflammatory properties. Nevertheless, there are still no data about flavanone's influence and its potential effects on the healthy aging process and improving pituitary functioning. Thus, using qPCR, immunoblot, histological techniques, and biochemical assays, our study aimed to elucidate how citrus flavanones (15 mg/kg b.m. per os) affect antioxidant defense, inflammation, and stress hormone output in the old rat model. Our results showed that HES restores the redox environment in the pituitary by down-regulating the nuclear factor erythroid 2-related factor 2 (Nrf2) protein while increasing kelch-like ECH-associated protein 1 (Keap1), thioredoxin reductase (TrxR1), and superoxide dismutase 2 (SOD2) protein expression. Immunofluorescent analysis confirmed Nrf2 and Keap1 down- and up-regulation, respectively. Supplementation with NAR increased Keap1, Trxr1, glutathione peroxidase (Gpx), and glutathione reductase (Gr) mRNA expression. Decreased oxidative stress aligned with NLRP3 decrement after both flavanones and glycogen synthase kinase-3 (GSK3) only after HES. The signal intensity of adrenocorticotropic hormone (ACTH) cells did not change, while corticosterone levels in serum decreased after both flavanones. HES showed higher potential than NAR in affecting a redox environment without increasing the inflammatory response, while a decrease in corticosterone level has a solid link to longevity. Our findings suggest that HES could improve and facilitate redox and inflammatory dysregulation in the rat's old pituitary.

Dihydrotanshinone I inhibits gallbladder cancer growth by targeting the Keap1-Nrf2 signaling pathway and Nrf2 phosphorylation

BACKGROUND

Gallbladder cancer (GBC) poses a significant risk to human health. Its development is influenced by numerous factors, particularly the homeostasis of reactive oxygen species (ROS) within cells. This homeostasis is crucial for tumor cell survival, and abnormal regulation of ROS is associated with the occurrence and progression of many cancers. Dihydrotanshinone I (DHT I), a biologically effective ingredient isolated from Salvia miltiorrhiza, has exhibited cytotoxic properties against various tumor cells by inducing apoptosis. However, the precise molecular mechanisms by which dht I exerts its cytotoxic effects remain unclear.

PURPOSE

To explore the anti-tumor impact of dht I on GBC and elucidate the potential molecular mechanisms.

METHODS

The proliferation of GBC cells, NOZ and SGC-996, was assessed using various assays, including CCK-8 assay, colony formation assay and EdU staining. We also examined cell apoptosis, cell cycle progression, ROS levels, and alterations in mitochondrial membrane potential to delve into the intricate molecular mechanism. Quantitative PCR (qPCR), immunofluorescence staining, and Western blotting were performed to evaluate target gene expression at both the mRNA and protein levels. The correlation between nuclear factor erythroid 2-related factor 2 (Nrf2) and kelch-like ECH-associated protein 1 (Keap1) were examined using co-immunoprecipitation. Finally, the in vivo effect of dht I was investigated using a xenograft model of gallbladder cancer in mice.

RESULTS

Our research findings indicated that dht I exerted cytotoxic effects on GBC cells, including inhibiting proliferation, disrupting mitochondrial membrane potential, inducing oxidative stress and apoptosis. Our in vivo studies substantiated the inhibition of dht I on tumor growth in xenograft nude mice. Mechanistically, dht I primarily targeted Nrf2 by promoting Keap1 mediated Nrf2 degradation and inhibiting protein kinase C (PKC) induced Nrf2 phosphorylation. This leads to the suppression of Nrf2 nuclear translocation and reduction of its target gene expression. Moreover, Nrf2 overexpression effectively counteracted the anti-tumor effects of dht I, while Nrf2 knockdown significantly enhanced the inhibitory effect of dht I on GBC. Meanwhile, PKC inhibitors and nuclear import inhibitors increased the sensitivity of GBC cells to dht I treatment. Conversely, Nrf2 activators, proteasome inhibitors, antioxidants and PKC activators all antagonized dht I induced apoptosis and ROS generation in NOZ and SGC-996 cells.

CONCLUSION

Our findings indicated that dht I inhibited the growth of GBC cells by regulating the Keap1-Nrf2 signaling pathway and Nrf2 phosphorylation. These insights provide a strong rationale for further investigation of dht I as a potential therapeutic agent for GBC treatment.

17β-estradiol Inhibits Oxidative Stress-Induced Apoptosis in Endometrial Cancer Cells by Promoting FOXM1 Expression

The steroid hormone 17β-estradiol (E2) has a significant impact on the development and progression of tumors. E2 stimulates tumor cell growth and metabolism, leading to an increase in reactive oxygen species (ROS) production. However, the rise in ROS levels is not sufficient to cause severe harm to cancer cells. and the mechanisms that regulate ROS are not well understood. Since FOXM1 plays a crucial role in the production of ROS, we aimed to investigate the impact of E2 on oxidative stress and the involvement of FOXM1 in the Ishikawa endometrial cancer cell line. Our research revealed that E2 controls the levels of ROS inside cells and safeguards them from apoptosis by promoting the expression of FOXM1. We observed a decrease in the expression of FOXM1 alongside an increase in oxidative damage. Moreover, cells demonstrated elevated levels of FOXM1 and ERα upon E2 treatment. Overall, our findings suggest that E2 prevents apoptosis induced by oxidative stress in endometrial cancer cells by encouraging the expression of FOXM1, potentially affecting ERα.

The development of nanocarriers for natural products

Natural bioactive compounds from plants exhibit substantial pharmacological potency and therapeutic value. However, the development of most plant bioactive compounds is hindered by low solubility and instability. Conventional pharmaceutical forms, such as tablets and capsules, only partially overcome these limitations, restricting their efficacy. With the recent development of nanotechnology, nanocarriers can enhance the bioavailability, stability, and precise intracellular transport of plant bioactive compounds. Researchers are increasingly integrating nanocarrier-based drug delivery systems (NDDS) into the development of natural plant compounds with significant success. Moreover, natural products benefit from nanotechnological enhancement and contribute to the innovation and optimization of nanocarriers via self-assembly, grafting modifications, and biomimetic designs. This review aims to elucidate the collaborative and reciprocal advancement achieved by integrating nanocarriers with botanical products, such as bioactive compounds, polysaccharides, proteins, and extracellular vesicles. This review underscores the salient challenges in nanomedicine, encompassing long-term safety evaluations of nanomedicine formulations, precise targeting mechanisms, biodistribution complexities, and hurdles in clinical translation. Further, this study provides new perspectives to leverage nanotechnology in promoting the development and optimization of natural plant products for nanomedical applications and guiding the progression of NDDS toward enhanced efficiency, precision, and safety. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

A Comparison between Bulgarian Tanacetum parthenium Essential Oil from Two Different Locations

Tanacetum parthenium L. (Asteraceae) is a perennial herbaceous plant with a long-standing historical use in traditional medicine. Recently Tanacetum parthenium L. essential oil has been associated with a promising potential for future applications in the pharmaceutical industry, in the cosmetics industry, and in agriculture. Investigations on the essential oil (EO) have indicated antimicrobial, antioxidant, and repellent activity. The present study aimed to evaluate the chemical composition of Bulgarian T. parthenium essential oil from two different regions, to compare the results to those reported previously in the literature, and to point out some of its future applications. The essential oils of the air-dried flowering aerial parts were obtained by hydrodistillation using a Clevenger-type apparatus. The chemical composition was evaluated using gas chromatography with mass spectrometry (GC-MS). It was established that the oxygenated monoterpenes were the predominant terpene class, followed by the monoterpene hydrocarbons. Significant qualitative and quantitative differences between both samples were revealed. Camphor (50.90%), camphene (16.12%), and bornyl acetate (6.05%) were the major constituents in the feverfew EO from the western Rhodope Mountains, while in the EO from the central Balkan mountains camphor (45.54%), trans-chrysanthenyl acetate (13.87%), and camphene (13.03%) were the most abundant components.

The influence of Nrf2 gene promoter methylation on gene expression and oxidative stress parameters in preeclampsia

BACKGROUND AND AIMS

Preeclampsia (PE) is a serious medical condition that usually causes high blood pressure and affects multiple organs. Considering the adverse effect of oxidative stress on the process of PE in pregnant women and regarding the role of the Nrf2 gene in placental oxidative pathways, this study was conducted to investigate the DNA methylation status of Nrf2 in PE and healthy pregnant women.

MATERIALS AND METHODS

The present case-control study consisted of 70 PE and 70 healthy pregnant women. Blood and placenta samples were taken from all subjects, and the percentage of the Nrf2 gene methylation in the samples was assessed by the Methyl Light PCR method. Also, the Nrf2 gene expression was evaluated by real-time PCR. The total antioxidant capacity (TAC) and total oxidative status (TOS) were measured by the colorimetric method.

RESULTS

In PE women, there was a significant increase in blood pressure, term of pregnancy, and BMI. In addition, there were enhanced Nrf2 DNA methylation percentage in placenta tissue and increased TOS levels in placenta tissue and blood compared to healthy pregnant women (P < 0.05). Also, in the PE group, there was a significant decrease in Nrf2 gene expression and TAC level in placenta tissue compared to the control group (P < 0.05).

CONCLUSION

The Nrf2 gene undergoes epigenetic modifications of DNA hypermethylation in the PE placenta. Decreased expression of this gene and the changes in the level of oxidative parameters (TAC, TOS) confirm it.

Dietary solutions for aluminum embryotoxicity: A study in Danio rerio using spirulina and okra-spirulina diets

Aluminum (Al) is a versatile element commonly employed in various industries and water treatment processes. However, its presence in aquatic ecosystems can elicit adverse effects on organisms, particularly the Danio rerio fish species. Aluminum exposure has been associated with a spectrum of issues, ranging from oxidative stress to behavioral anomalies, reproductive disruptions, and morphological alterations in these organisms. This research aimed to assess the impact of aluminum chloride (AlCl3) on D. rerio embryos and explore strategies to mitigate its effects. Three dietary groups (commercial, okra-spirulina, and spirulina) were studied, focusing on embryonic development, oxidative damage, and gene expression changes. The study revealed that diets enriched with spirulina and okra-spirulina effectively reduced aluminum-induced embryotoxicity, oxidative stress, and gene expression alterations, surpassing the commercial diet. However, all AlCl3-exposed groups experienced adverse effects on embryonic development, including hatching anomalies, structural deformities, and cardiac delays. The okra-spirulina group showed milder toxic responses. In conclusion, this study highlights the potential of spirulina and okra-spirulina diets in mitigating aluminum-triggered oxidative stress and apoptosis in D. rerio. It underscores the need for future research on embryonic development and carries significant implications for environmental conservation and the well-being of aquatic organisms in aluminum-contaminated environments.

Ameliorative inhibition of sirtuin 6 by imidazole derivative triggers oxidative stress-mediated apoptosis associated with Nrf2/Keap1 signaling in non-small cell lung cancer cell lines

Background: Redox homeostasis is the vital regulatory system with respect to antioxidative response and detoxification. The imbalance of redox homeostasis causes oxidative stress. Nuclear factor-erythroid 2 p45-related factor 2 (Nrf2, also called Nfe2l2)/Kelchlike ECH-associated protein 1 (Keap1) signaling is the major regulator of redox homeostasis. Nrf2/Keap1 signaling is reported to be involved in cancer cell growth and survival. A high level of Nrf2 in cancers is associated with poor prognosis, resistance to therapeutics, and rapid proliferation, framing Nrf2 as an interesting target in cancer biology. Sirtuins (SIRT1-7) are class III histone deacetylases with NAD + dependent deacetylase activity that have a remarkable impact on antioxidant and redox signaling (ARS) linked with Nrf2 deacetylation thereby increasing its transcription by epigenetic modifications which has been identified as a crucial event in cancer progression under the influence of oxidative stress in various transformed cells. SIRT6 plays an important role in the cytoprotective effect of multiple diseases, including cancer. This study aimed to inhibit SIRT6 using an imidazole derivative, Ethyl 2-[5-(4-chlorophenyl)-2-methyl-1-H-Imidazole-4-yl] acetate, to assess its impact on Nrf2/Keap1 signaling in A549 and NCI-H460 cell lines. Method: Half maximal inhibitory concentration (IC50) of Ethyl 2-[5-(4-chlorophenyl)-2-methyl-1-H-Imidazole-4-yl] acetate was fixed by cell viability assay. The changes in the gene expression of important regulators involved in this study were examined using quantitative real-time PCR (qRT-PCR) and protein expression changes were confirmed by Western blotting. The changes in the antioxidant molecules are determined by biochemical assays. Further, morphological studies were performed to observe the generation of reactive oxygen species, mitochondrial damage, and apoptosis. Results: We inhibited SIRT6 using Ethyl 2-[5-(4-chlorophenyl)-2-methyl-1-H-Imidazole-4-yl] acetate and demonstrated that SIRT6 inhibition impacts the modulation of antioxidant and redox signaling. The level of antioxidant enzymes and percentage of reactive oxygen species scavenging activity were depleted. The morphological studies showed ROS generation, mitochondrial damage, nuclear damage, and apoptosis. The molecular examination of apoptotic factors confirmed apoptotic cell death. Further, molecular studies confirmed the changes in Nrf2 and Keap1 expression during SIRT6 inhibition. Conclusion: The overall study suggests that SIRT6 inhibition by imidazole derivative disrupts Nrf2/Keap1 signaling leading to oxidative stress and apoptosis induction.

Role of SLC7A11/xCT in Ovarian Cancer

Ovarian cancer is one of the most dangerous gynecologic cancers worldwide and has a high fatality rate due to diagnosis at an advanced stage of the disease as well as a high recurrence rate due to the occurrence of chemotherapy resistance. In fact, chemoresistance weakens the therapeutic effects, worsening the outcome of this pathology. Solute Carrier Family 7 Member 11 (SLC7A11, also known as xCT) is the functional subunit of the Xc- system, an anionic L-cystine/L-glutamate antiporter expressed on the cell surface. SLC7A11 expression is significantly upregulated in several types of cancers in which it can inhibit ferroptosis and favor cancer cell proliferation, invasion and chemoresistance. SLC7A11 expression is also increased in ovarian cancer tissues, suggesting a possible role of this protein as a therapeutic target. In this review, we provide an overview of the current literature regarding the role of SLC7A11 in ovarian cancer to provide new insights on SLC7A11 modulation and evaluate the potential role of SLC7A11 as a therapeutic target.

Alpha-Lipoic Acid Reduces Cell Growth, Inhibits Autophagy, and Counteracts Prostate Cancer Cell Migration and Invasion: Evidence from In Vitro Studies

Alpha-lipoic acid (ALA) is a natural antioxidant dithiol compound, exerting antiproliferative and antimetastatic effects in various cancer cell lines. In our study, we demonstrated that ALA reduces the cell growth of prostate cancer cells LNCaP and DU-145. Western blot results revealed that in both cancer cells, ALA, by upregulating pmTOR expression, reduced the protein content of two autophagy initiation markers, Beclin-1 and MAPLC3. Concomitantly, MTT assays showed that chloroquine (CQ) exposure, a well-known autophagy inhibitor, reduced cells' viability. This was more evident for treatment using the combination ALA + CQ, suggesting that ALA can reduce cells' viability by inhibiting autophagy. In addition, in DU-145 cells we observed that ALA affected the oxidative/redox balance system by deregulating the KEAP1/Nrf2/p62 signaling pathway. ALA decreased ROS production, SOD1 and GSTP1 protein expression, and significantly reduced the cytosolic and nuclear content of the transcription factor Nrf2, concomitantly downregulating p62, suggesting that ALA disrupted p62-Nrf2 feedback loop. Conversely, in LNCaP cells, ALA exposure upregulated both SOD1 and p62 protein expression, but did not affect the KEAP1/Nrf2/p62 signaling pathway. In addition, wound-healing, Western blot, and immunofluorescence assays evidenced that ALA significantly reduced the motility of LNCaP and DU-145 cells and downregulated the protein expression of TGFβ1 and vimentin and the deposition of fibronectin. Finally, a soft agar assay revealed that ALA decreased the colony formation of both the prostate cancer cells by affecting the anchorage independent growth. Collectively, our in vitro evidence demonstrated that in prostate cancer cells, ALA reduces cell growth and counteracts both migration and invasion. Further studies are needed in order to achieve a better understanding of the underlined molecular mechanisms.

Lymphoid-specific helicase inhibits cervical cancer cells ferroptosis by promoting Nrf2 expression

Background

Cervical cancer is a major cause of morbidity and mortality in women worldwide. The underlying mechanisms of its progression are not well understood. In this study, we investigated the role of lymphoid-specific helicase (HELLS) in cervical cancer.

Methods

We measured HELLS expression in cervical cancer and assessed its function using gain- and loss-of-function experiments. Cell viability was measured using the Cell Counting Kit-8 (CCK8 ) assay, and cell proliferation was analyzed using colony formation and EdU assays.

Results

We found that HELLS was significantly increased in cervical cancer and that its overexpression promoted cell viability (P < 0.01) and colony formation (P < 0.001). In contrast, si-HELLS suppressed these effects. Moreover, HELLS overexpression inhibited cell death induced by the ferroptosis inducer erastin (P < 0.01). Mechanistically, we found that HELLS promoted cervical cancer proliferation by regulating nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated ferroptosis.

Conclusion

Our data suggest that HELLS promotes cervical cancer proliferation by inhibiting Nrf2 expression. Therefore, HELLS knockdown may be an effective treatment for cervical cancer.

Attenuation of Oxidative Damage via Upregulating Nrf2/HO-1 Signaling Pathway by Protease SH21 with Exerting Anti-Inflammatory and Anticancer Properties In Vitro

Oxidative damage and inflammation are among the very significant aspects interrelated with cancer and other degenerative diseases. In this study, we investigated the biological activities of a 25 kDa protease (SH21) that was purified from Bacillus siamensis. SH21 exhibited very powerful antioxidant and reactive oxygen species (ROS) generation inhibition activity in a dose-dependent approach. The mRNA and protein levels of antioxidant enzymes such as superoxide dismutase 1 (SOD1), catalase (CAT), and glutathione peroxidase 1 (GPx-1) were enhanced in the SH21-treated sample. SH21 also increased the transcriptional and translational activities of NF-E2-related factor 2 (Nrf2) with the subsequent development of detoxifying enzyme heme oxygenase-1 (HO-1). In addition, SH21 showed potential anti-inflammatory activity via inhibition of nitric oxide (NO) and proinflammatory cytokines, such as TNF-α, IL-6, and IL-1β, production in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. At concentrations of 60, 80, and 100 μg/mL, SH21 potentially suppressed nitric oxide synthase (iNOS) and cytokine gene expressions. Furthermore, SH21 significantly released lactate dehydrogenase (LDH) enzyme in cancer cell supernatant in a concentration-dependent manner and showed strong activity against three tested cancer cell lines, including HL-60, A549, and Hela. Our results suggest that SH21 has effective antioxidant, anti-inflammatory, and anticancer effects and could be an excellent therapeutic agent against inflammation-related diseases.

Paradox: Curcumin, a Natural Antioxidant, Suppresses Osteosarcoma Cells via Excessive Reactive Oxygen Species

Osteosarcoma (OS) is an aggressive tumor with a rare incidence. Extended surgical resections are the prevalent treatment for OS, which may cause critical-size bone defects. These bone defects lead to dysfunction, weakening the post-surgical quality of patients' life. Hence, an ideal therapeutic agent for OS should simultaneously possess anti-cancer and bone repair capacities. Curcumin (CUR) has been reported in OS therapy and bone regeneration. However, it is not clear how CUR suppresses OS development. Conventionally, CUR is considered a natural antioxidant in line with its capacity to promote the nuclear translocation of a nuclear transcription factor, nuclear factor erythroid 2 (NRF2). After nuclear translocation, NRF2 can activate the transcription of some antioxidases, thereby circumventing excess reactive oxygen species (ROS) that are deleterious to cells. Intriguingly, this research demonstrated that, in vitro, 10 and 20 μM CUR increased the intracellular ROS in MG-63 cells, damaged cells' DNA, and finally caused apoptosis of MG-63 cells, although increased NRF2 protein level and the expression of NRF2-regulated antioxidase genes were identified in those two groups.

Opioids Alleviate Oxidative Stress via the Nrf2/HO-1 Pathway in LPS-Stimulated Microglia

Opioids are known to have antioxidant effects and to modulate microglial function under certain conditions. It has been previously shown that opioid ligands can effectively inhibit the release of proinflammatory cytokines when stimulated with lipopolysaccharide (LPS) and convert microglia to an anti-inflammatory polarization state. Here, we used C8-B4 cells, the mouse microglial cell line activated by LPS as a model to investigate the anti-inflammatory/antioxidant potential of selected opioid receptor agonists (DAMGO, DADLE, and U-50488). We found that all of these ligands could exert cytoprotective effects through the mechanism affecting LPS-induced ROS production, NADPH synthesis, and glucose uptake. Interestingly, opioids elevated the level of reduced glutathione, increased ATP content, and enhanced mitochondrial respiration in microglial cells exposed to LPS. These beneficial effects were associated with the upregulation of the Nrf2/HO-1 pathway. The present results indicate that activation of opioid signaling supports the preservation of mitochondrial function with concomitant elimination of ROS in microglia and suggest that an Nrf2/HO-1 signaling pathway-dependent mechanism is involved in the antioxidant efficacy of opioids. Opioid receptor agonists may therefore be considered as agents to suppress oxidative stress and inflammatory responses of microglia.

Dihydro-Resveratrol Attenuates Oxidative Stress, Adipogenesis and Insulin Resistance in In Vitro Models and High-Fat Diet-Induced Mouse Model via AMPK Activation

Management of obesity has become a prevalent strategy for preventing the diseases closely integrated with excess body weight such as diabetes over the last half century. Searching for therapeutic agents acting on oxidative stress, adipogenesis and insulin resistance is considered as an efficient approach to control obesity-related diseases. The present study was designed to examine the in vitro and in vivo effects of dihydro-resveratrol (DR2), a naturally occurring compound from Dendrobium medicinal plants, on oxidative stress aggravation, adipogenesis, lipogenesis and insulin sensitivity. We utilized an in vitro 3T3-L1 adipocyte differentiation model to show that DR2 could reduce pre-adipocyte maturation by activation of AMPK/SIRT1 signaling proteins to inhibit p38MAPK proteins. With the use of in vitro oxidative-stress-induced hepatocytes and myoblasts models, DR2 was also shown to be able to reduce oxidative stress aggravation through mediation of Nrf2-related antioxidative cascade, reduce intracellular lipid accumulation through phosphorylation of ACC protein, reduce lipid peroxidation in hepatocytes and promote insulin sensitivity via activation of AKT protein in the insulin-resistant HepG2 cells and C2C12 cells. The effects of DR2 on adipogenesis, lipid accumulation, insulin resistance and blood glucose clearance were further demonstrated in the high-fat diet-induced obesity mouse model. Our in vitro and in vivo studies determined that DR2 could contain therapeutic potential for the treatment of obesity and type 2 diabetes.