Targeting NRF2 to treat cancer

Resveratrol targeting NRF2 disrupts the binding between KEAP1 and NRF2-DLG motif to ameliorate oxidative stress damage in mice pulmonary infection

ETHNOPHARMACOLOGICAL RELEVANCE

The root of Polygonum cuspidatum Sieb. et Zucc (PC), known as 'Huzhang' in the Chinese Pharmacopoeia, has been traditionally employed for its anti-inflammatory, antiviral, antimicrobial, and other biological activities. Polydatin (PD) and its aglycone, resveratrol (RES), are key pharmacologically active components responsible for exerting anti-inflammatory and antioxidant effects. However, its specific targets and action mechanisms remain unclear.

AIM OF THE STUDY

The equilibrium of the KEAP1-NRF2 system serves as the primary protective response to oxidative and electrophilic stresses within the body, particularly in cases of acute lung injury caused by pathogenic microbial infection. In this study, the precise mechanisms by which RES alleviates oxidative stress damage in conjunction with NRF2 activators are discussed.

MATERIALS AND METHODS

The active components from PC were screened to evaluate their potential to inhibit reactive oxygen species (ROS) and activate antioxidant activity dependent on antioxidant response elements (ARE). RES was evaluated for its potential to alleviate the oxidative stress caused by pathogenic microbial infection. Functional probes were designed to study the RES distribution and identify its targets. A lipopolysaccharide (LPS)-induced oxidative injury model was used to evaluate the effects of RES on the KEAP1-NRF2/ARE pathway in RAW 264.7 cells. The interaction between RES and NRF2 was elucidated using drug-affinity responsive target stability (DARTS), cellular thermal shift assays (CETSA), co-immunoprecipitation (Co-IP), and microscale thermophoresis (MST) techniques. The key binding sites were predicted using molecular docking and validated in NRF2-knockdownand reconstructed cells. Finally, protective effects against pulmonary stress were verified in a mouse model of pathogenic infection.

RESULTS

The accumulation of RES in lung macrophages disrupted the binding between KEAP1 and NRF2, thereby preventing the ubiquitination degradation of NRF2 through its interaction with Ile28 on the NRF2-DLG motif. The activation of NRF2 resulted in the upregulation of nuclear transcription, enhances the expression of antioxidant genes dependent on ARE, suppresses ROS generation, and ameliorates oxidative damage both in vivo and in vitro.

CONCLUSION

These findings shed light on the potential of RES to mitigate oxidative stress damage caused by pathogenic microorganism-induced lung infections and facilitate the discovery of novel small molecule modulators targeting the KEAP1-NRF2 DLG motif interaction.

Cytochrome P450 F3 promotes colorectal cancer via inhibiting NRF2-mediated ferroptosis

Cytochrome P450 F3 (CYP4F3) is recognized as a disease-associated immune response initiator that is involved in the synthesis of cholesterol, steroids, and lipids. This study identified the upregulation of CYP4F3 expression in colorectal cancer (CRC) and its association with poor patient prognosis through a comparative analysis between CRC tumor tissues with normal tissues from public databases. The overexpression of CYP4F3 in CT26.wt and SW620, promoted cell proliferation and migration, a reduction of cellular oxidative stress, an up-regulation of the oxidative stress-related pathway NRF2, and an inhibition of cellular ferroptosis. Additionally, inhibition of NRF2 activity stimulated cellular ferroptosis when CYP4F3 was overexpressed. Ferroptosis, characterized by iron-dependent lipid peroxidation, is a non-apoptotic way of cell death with a critical role in cancer development. When given a ferroptosis agonist to CYP4F3-overexpression CRC cells, NRF2 was activated, and cell proliferation and migration were reduced. Furthermore, the mice subcutaneously injected with CYP4F3-overexpression CT26.wt cells formed significantly larger tumors compared to the CYP4F3-vector CT26.wt cell group. This study systematically identified an important role of CYP4F3 in CRC development as a regulator of CRC cells to escape ferroptosis via NRF2, highlighting the significance of CYP4F3 as a potential therapeutic target for CRC.

Gaudichaudione H ameliorates liver fibrosis and inflammation by targeting NRF2 signaling pathway

Gaudichaudione H (GH) is a natural small molecular compound isolated from Garcinia oligantha Merr. (Clusiaceae). Being an uncommon rare caged polyprenylated xanthone, the potential pharmacological functions of GH remain to be fully elucidated currently. In this study, we primarily focused on identifying potential bioavailable targets and elucidating related therapeutic actions. Herein, the network pharmacology analysis, metabolomics analysis and genome-wide mRNA transcription assay were performed firstly to predict the major pharmacological action and potential targets of GH. To confirm the hypothesis, gene knockout model was created using CRISPR/Cas9 method. The pharmacological action of GH was evaluated in vitro and in vivo. Firstly, our results of network pharmacology analysis and omics assay indicated that GH significantly activated NRF2 signaling pathway, and the function could be associated with liver disease treatment. Then, the pharmacological action of GH was evaluated in vitro and in vivo. The treatment with GH significantly increased the protein levels of NRF2 and promoted the transcription of NRF2 downstream genes. Further analysis suggested that GH regulated NRF2 through an autophagy-mediated non-canonical mechanism. Additionally, the administration of GH effectively protected the liver from carbon tetrachloride (CCl4)-induced liver fibrosis and inflammation, which depended on the activation of NRF2 in hepatic stellate cells and inflammatory cells respectively. Collectively, our findings underscore the potential therapeutic effect of GH on alleviating hepatic fibrosis and inflammation through the augmentation of NRF2 signaling pathway, providing a promising avenue for the treatment of liver fibrosis and inflammation in clinical settings.

Nrf2 pathways in neuroprotection: Alleviating mitochondrial dysfunction and cognitive impairment in aging

Mitochondrial dysfunction and cognitive impairment are widespread phenomena among the elderly, being crucial factors that contribute to neurodegenerative diseases. Nuclear factor erythroid 2-related factor 2 (Nrf2) is an important regulator of cellular defense systems, including that against oxidative stress. As such, increased Nrf2 activity may serve as a strategy to avert mitochondrial dysfunction and cognitive decline. Scientific data on Nrf2-mediated neuroprotection was collected from PubMed, Google Scholar, and Science Direct, specifically addressing mitochondrial dysfunction and cognitive impairment in older people. Search terms included "Nrf2", "mitochondrial dysfunction," "cognitive impairment," and "neuroprotection." Studies focusing on in vitro and in vivo models and clinical investigations were included to review Nrf2's therapeutic potential comprehensively. The relative studies have demonstrated that increased Nrf2 activity could improve mitochondrial performance, decrease oxidative pressure, and mitigate cognitive impairment. To a large extent, this is achieved through the modulation of critical cellular signalling pathways such as the Keap1/Nrf2 pathway, mitochondrial biogenesis, and neuroinflammatory responses. The present review summarizes the recent progress in comprehending the molecular mechanisms regarding the neuroprotective benefits mediated by Nrf2 through its substantial role against mitochondrial dysfunction and cognitive impairment. This review also emphasizes Nrf2-target pathways and their contribution to cognitive function improvement and rescue from mitochondria-related abnormalities as treatment strategies for neurodegenerative diseases that often affect elderly individuals.

Viola yedoensis Makino alleviates lipopolysaccharide-induced intestinal oxidative stress and inflammatory response by regulating the gut microbiota and NF-κB-NLRP3/ Nrf2-MAPK signaling pathway in broiler

Viola yedoensis Makino (Vy) is a well-known traditional Chinese medicine widely used to treat inflammatory diseases. However, the regulatory effects of dietary Vy supplementation on lipopolysaccharide (LPS)-induced intestinal damage in broilers and the underlying molecular mechanisms remain unclear. In this study, broilers were intraperitoneally injected with 1 mg/kg LPS on days 17, 19 and 21 to induce intestinal damage. Vy supplementation at 0.5, 1.5 and 4.5 % in the diet was administered separately for 21 days to investigate the potential protective effects of Vy supplementation against LPS-induced intestinal impairment in broilers. Vy supplementation improved intestinal morphology and restored growth performance. Vy supplementation attenuated intestinal inflammation by regulating the nuclear factor kappa B (NF-κB) / NLR family pyrin domain-containing 3 (NLRP3) signaling pathway and inhibited its downstream pro-inflammatory factor levels. In addition, Vy supplementation relieved intestinal oxidative impairment by regulating the nuclear factor erythroid-2 related factor 2 (Nrf2) / mitogen-activated protein kinase (MAPK) signaling pathway and downstream antioxidant enzyme activity. Vy supplementation reduced LPS-induced mitochondrial damage and apoptosis. Furthermore, Vy supplementation alleviated LPS-induced intestinal inflammation and oxidative damage in chickens by increasing the abundance of protective bacteria (Lactobacillus and Romboutsia) and reducing the number of pathogenic bacteria (unclassified_f_Ruminococcaceae, unclassified_f_Oscillospiraceae and norank_f_norank_o_Clostridia_vadinBB60_group). Overall, Vy supplementation effectively ameliorated LPS-induced intestinal damage by regulating the NF-κB-NLRP3/Nrf2-MAPK signaling pathway and maintaining intestinal microbiota balance. Vy supplementation can be used as a dietary supplement to protect broilers against intestinal inflammation and oxidative damage.

The deubiquitinating enzyme USP35 regulates the stability of NRF2 protein

Many cancers exhibit resistance to chemotherapy, resulting in a poor prognosis. The transcription factor NRF2, activated in response to cellular antioxidants, plays a crucial role in cell survival, proliferation, and resistance to chemotherapy. This factor may serve as a promising target for therapeutic interventions in esophageal carcinoma. Recent research suggests that NRF2 activity is modulated by ubiquitination mediated by the KEAP1-CUL3 E3 ligase complex, highlighting the importance of deubiquitination. However, the specific deubiquitinase responsible for regulating NRF2 in esophageal cancer remains unknown. In this study, a novel regulator of the NRF2 protein, Ubiquitin-Specific Protease 35 (USP35), has been identified. Mechanistically, USP35 modulates NRF2 stability through enzymatic deubiquitination. USP35 interacts with NRF2 and facilitates its deubiquitination. Knockdown of USP35 leads to a notable increase in NRF2 levels and enhances the sensitivity of cells to chemotherapy. These findings suggest that the USP35-NRF2 axis is a key player in the regulation of therapeutic strategies for esophageal cancer.

DDX5 deficiency drives non-canonical NF-κB activation and NRF2 expression, influencing sorafenib response and hepatocellular carcinoma progression

In advanced hepatocellular carcinoma (HCC), RNA helicase DDX5 regulates the Wnt/β-catenin-ferroptosis axis, influencing the efficacy of the multi-tyrosine kinase inhibitor (mTKI) sorafenib. DDX5 inhibits Wnt/β-catenin signaling, preventing sorafenib-induced ferroptosis escape. Sorafenib/mTKIs reduce DDX5 expression, correlating with poor patient survival post-sorafenib treatment. Notably, DDX5-knockout in HCC cells activates Wnt/β-catenin signaling persistently. Herein, we investigate the mechanistic impact of Wnt/β-catenin activation resulting from DDX5 downregulation in the progression and treatment of HCC. RNAseq analyses identified shared genes repressed by DDX5 and upregulated by sorafenib, including Wnt signaling genes, NF-κB-inducing kinase (NIK) essential for non-canonical NF-κB (p52/RelB) activation, and cytoprotective transcription factor NRF2. We demonstrate, Wnt/β-catenin activation induced NIK transcription, leading to non-canonical NF-κB activation, which subsequently mediated NRF2 transcription. Additionally, DDX5 deficiency extended NRF2 protein half-life by inactivating KEAP1 through p62/SQSTM1 stabilization. In a preclinical HCC mouse model, NRF2 knockdown or DDX5 overexpression restricted tumor growth upon sorafenib treatment, via induction of ferroptosis. Importantly, DDX5-knockout HCC cells exhibited elevated expression of Wnt signaling genes, NIK, p52/RelB, and NRF2-regulated genes, regardless of sorafenib treatment. Transcriptomic analyses of HCCs from TCGA and the Stelic Animal Model (STAM) of non-alcoholic steatohepatitis revealed elevated expression of these interconnected pathways in the context of DDX5 downregulation. In conclusion, DDX5 deficiency triggers Wnt/β-catenin signaling, promoting p52/RelB and NRF2 activation, thereby enabling ferroptosis evasion upon sorafenib treatment. Similarly, independent of sorafenib, DDX5 deficiency in liver tumors enhances activation and gene expression of these interconnected pathways, underscoring the clinical relevance of DDX5 deficiency in HCC progression and therapeutic response.

m6A demethylation of FOSL1 mRNA protects hepatoma cells against necrosis under glucose deprivation

Stress-adaptive mechanisms enabling cancer cells to survive under glucose deprivation remain elusive. N6-methyladenosine (m6A) modification plays important roles in determining cancer cell fate and cellular stress response to nutrient deficiency. However, whether m6A modification functions in the regulation of cancer cell survival under glucose deprivation is unknown. Here, we found that glucose deprivation reduced m6A modification levels. Increasing m6A modification resulted in increased hepatoma cell necrosis under glucose deprivation, whereas decreasing m6A modification had an opposite effect. Integrated m6A-seq and RNA-seq revealed potential targets of m6A modification under glucose deprivation, including the transcription factor FOSL1; further, glucose deprivation upregulated FOSL1 by inhibiting FOSL1 mRNA decay in an m6A-YTHDF2-dependent manner through reducing m6A modification in its exon1 and 5'-UTR regions. Functionally, FOSL1 protected hepatoma cells against glucose deprivation-induced necrosis in vitro and in vivo. Mechanistically, FOSL1 transcriptionally repressed ATF3 by binding to its promoter. Meanwhile, ATF3 and MAFF interacted via their leucine zipper domains to form a heterodimer, which competed with NRF2 for binding to antioxidant response elements in the promoters of NRF2 target genes, thereby inhibiting their transcription. Consequently, FOSL1 reduced the formation of the ATF3-MAFF heterodimer, thereby enhancing NRF2 transcriptional activity and the antioxidant capacity of glucose-deprived-hepatoma cells. Thus, FOSL1 alleviated the necrosis-inducing effect of glucose deprivation-induced reactive oxygen species accumulation. Collectively, our study uncovers the protective role of m6A-FOSL1-ATF3 axis in hepatoma cell necrosis under glucose deprivation, and may provide new targets for cancer therapy.

Research progress of sorafenib drug delivery system in the treatment of hepatocellular carcinoma: An update

Hepatocellular carcinoma (HCC) is one of the most prevalent malignant tumors in the contemporary era, representing a significant global health concern. Early HCC patients have mild symptoms or are asymptomatic, which promotes the onset and progression of the disease. Moreover, advanced HCC is insensitive to chemotherapy, making traditional clinical treatment unable to block cancer development. Sorafenib (SFB) is a first-line targeted drug for advanced HCC patients with anti-angiogenesis and anti-tumor cell proliferation effects. However, the efficacy of SFB is constrained by its off-target distribution, rapid metabolism, and multi-drug resistance. In recent years, nanoparticles based on a variety of materials have been demonstrated to enhance the targeting and therapeutic efficacy of SFB against HCC. Concurrently, the advent of joint drug delivery systems has furnished crucial empirical evidence for reversing SFB resistance. This review will summarize the application of nanotechnology in the field of HCC treatment over the past five years. It will focus on the research progress of SFB delivery systems combined with multiple therapeutic modalities in HCC treatment.

Nrf2 mediated signaling axis in heart failure: Potential pharmacological receptor

Heart failure (HF) has emerged as the most pressing health concerns globally, and extant clinical therapies are accompanied by side effects and patients have a high burden of financial. The protein products of nuclear factor erythroid 2-related factor 2 (Nrf2) target genes have a variety of cardioprotective effects, including antioxidant, metabolic functions and anti-inflammatory. By evaluating established preclinical and clinical research in HF to date, we explored the potential of Nrf2 to exert unique cardioprotective functions as a novel therapeutic receptor for HF. In this review, we generalize the progression, structure, and function of Nrf2 research in the cardiovascular system. The mechanism of action of Nrf2 involved in HF as well as agonists of Nrf2 in natural compounds are summarized. Additionally, we discuss the challenges and implications for future clinical translation and application of pharmacology targeting Nrf2. It's critical to developing new drugs for HF.

Single-cell RNA sequencing reveals that NRF2 regulates vascular smooth muscle cell phenotypic switching in abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a life-threatening disease characterized by extensive membrane destruction in the vascular wall that is closely associated with vascular smooth muscle cell (VSMC) phenotypic switching. A thorough understanding of the changes in regulatory factors during VSMC phenotypic switching is essential for managing AAA therapy. In this study, we revealed the impact of NRF2 on the modulation of VSMC phenotype and the development of AAA based on single-cell RNA sequencing analysis. By utilizing a murine model of VSMC-specific knockout of nuclear factor E2-related factor 2 (NRF2), we observed that the absence of NRF2 in VSMCs exacerbated AAA formation in an angiotensin II-induced AAA model. The downregulation of NRF2 promoted VSMC phenotypic switching, leading to an enhanced inflammatory response. Through genome-wide transcriptome analysis and loss- or gain-of-function experiments, we discovered that NRF2 upregulated the expression of VSMC contractile phenotype-specific genes by facilitating microRNA-145 (miR-145) expression. Our data identified NRF2 as a novel regulator involved in maintaining the VSMC contractile phenotype while also influencing AAA formation through an miR-145-dependent regulatory mechanism.

Nfe2l2/NRF2 Deletion Attenuates Tumorigenesis and Increases Bacterial Diversity in a Mouse Model of Lynch Syndrome

Lynch syndrome (LS) is the most prevalent heritable form of colorectal cancer. Its early onset and high lifetime risk for colorectal cancer emphasize the necessity for effective chemoprevention. NFE2L2 (NRF2) is often considered a potential druggable target, and many chemopreventive compounds induce NRF2. However, although NRF2 counteracts oxidative stress, it is also overexpressed in colorectal cancer and may promote tumorigenesis. In this study, we evaluated the role of NRF2 in the prevention of LS-associated neoplasia. We found increased levels of NRF2 in intestinal epithelia of mice with intestinal epithelium-specific Msh2 deletion (MSH2ΔIEC) compared with C57BL/6 (wild-type) mice, as well as an increase in downstream NRF2 targets NAD(P)H dehydrogenase (quinone 1) and glutamate-cysteine ligase catalytic subunit. Likewise, NRF2 levels were increased in human MSH2-deficient LS tumors compared with healthy human controls. In silico analysis of a publicly accessible RNA sequencing LS dataset also found an increase in downstream NRF2 targets. Upon crossing MSH2ΔIEC with Nrf2null (MSH2ΔIECNrf2null) mice, we unexpectedly found reduced tumorigenesis in MSH2ΔIECNrf2null mice compared with MSH2ΔIEC mice after 40 weeks, which occurred despite an increase in oxidative damage in MSH2ΔIECNrf2null mice. The loss of NRF2 impaired proliferation as seen by Ki67 intestinal staining and in organoid cultures. This was accompanied by diminished WNT/β-catenin signaling, but apoptosis was unaffected. Microbial α-diversity increased over time with the loss of NRF2 based upon 16S rRNA gene amplicon sequencing of murine fecal samples. Altogether, we show that NRF2 protein levels are increased in MSH2 deficiency and associated neoplasia, but the loss of NRF2 attenuates tumorigenesis. Activation of NRF2 may not be a feasible strategy for chemoprevention in LS. Prevention Relevance: Patients with LS have an early onset and high lifetime risk for colorectal cancer. In this study, we show that NRF2 protein levels are increased in MSH2 deficiency and associated neoplasia, but the loss of NRF2 attenuates tumorigenesis. This suggests that NRF2 may not be a tumor suppressor in this specific context.

Programmable activation of berbamine and photosensitizers for enhanced photodynamic therapy using emission-switchable upconversion nanoparticles

Photodynamic therapy (PDT) shows great potential in precision tumor treatment. However, its efficacy is inhibited by the antioxidant defense capacities of tumor cells. To address this challenge, a near-infrared light-controlled nanosystem (UCNPs@mSiO2@Azo@ZnPc&BBM, PB@UA) was developed using emission-switchable upconversion nanoparticles (UCNPs) to independently and precisely control the release of berbamine (BBM) and activation of photosensitizer for enhanced PDT in deep tissues. Firstly, BBM release was triggered by exciting PB@UA at 980 nm. The BBM could inhibit the activities of antioxidant enzymes and disrupt calcium ion regulation, making the tumor cells more susceptible to ROS-induced cell death in the following PDT treatment. The PDT was initiated by irradiating the photosensitizers of ZnPc on PB@UA at 808 nm and achieved a tumor inhibition rate of 80.91 % in vivo, which is significantly higher than that of unique PDT (31.78 %) or BBM (11.29 %) treatment and demonstrates the potential of our strategy for improved cancer treatment.

TRIP13 Plays an Important Role in the Sensitivity of Leukemia Cell Response to Sulforaphane Therapy

Sulforaphane is one of the most characterized isothiocyanate compounds in cruciferous vegetables and shows anticancer effects, especially antileukemia properties. However, the molecular mechanism of the growth inhibition effect of sulforaphane in acute myeloid leukemia (AML) has not been fully explored. In the present study, a proteomic analysis was performed on the AML cell line U937 responding to sulforaphane treatment to identify novel and efficient therapeutic targets of sulforaphane on AML cells. Key driver analysis was run on the leukemia network, and TRIP13 was identified as a key regulatory factor in sulforaphane-induced growth inhibition in U937 cells. Pretreatment with DCZ0415, an inhibitor of TRIP13, could significantly attenuate sulforaphane-induced cell apoptosis and cell cycle arrest in vitro through the PI3K/Akt/mTOR signaling pathway. In addition, the inhibitory effect of sulforaphane on the tumor volume could also be obviously attenuated by the pretreatment of DCZ0415 in vivo. These results indicate that TRIP13 plays an important role in the sensitivity of leukemia cell response to sulforaphane treatment, and these findings expand the understanding of the mechanism of the antileukemic effect of sulforaphane and provide a new target for the treatment of AML.

Inhibition of NRF2 signaling overcomes acquired resistance to arsenic trioxide in FLT3-mutated Acute Myeloid Leukemia

De novo acute myeloid leukemia (AML) patients with FMS-like tyrosine kinase 3 internal tandem duplications (FLT3-ITD) have worse treatment outcomes. Arsenic trioxide (ATO) used in the treatment of acute promyelocytic leukemia (APL) has been reported to be effective in degrading the FLT3 protein in AML cell lines and sensitizing non-APL AML patient samples in-vitro. We have previously reported that primary cells from FLT3-ITD mutated AML patients were sensitive to ATO in-vitro compared to other non-M3 AML and molecular/pharmacological inhibition of NF-E2 related factor 2 (NRF2), a master regulator of antioxidant response improved the chemosensitivity to ATO and daunorubicin even in non FLT3-ITD mutated cell lines and primary samples. We examined the effects of molecular/pharmacological suppression of NRF2 on acquired ATO resistance in the FLT3-ITD mutant AML cell line (MV4-11-ATO-R). ATO-R cells showed increased NRF2 expression, nuclear localization, and upregulation of bonafide NRF2 targets. Molecular inhibition of NRF2 in this resistant cell line improved ATO sensitivity in vitro. Digoxin treatment lowered p-AKT expression, abrogating nuclear NRF2 localization and sensitizing cells to ATO. However, digoxin and ATO did not sensitize non-ITD AML cell line THP1 with high NRF2 expression. Digoxin decreased leukemic burden and prolonged survival in MV4-11 ATO-R xenograft mice. We establish that altering NRF2 expression may reverse acquired ATO resistance in FLT3-ITD AML.

Iron metabolism: backfire of cancer cell stemness and therapeutic modalities

Cancer stem cells (CSCs), with their ability of self-renewal, unlimited proliferation, and multi-directional differentiation, contribute to tumorigenesis, metastasis, recurrence, and resistance to conventional therapy and immunotherapy. Eliminating CSCs has long been thought to prevent tumorigenesis. Although known to negatively impact tumor prognosis, research revealed the unexpected role of iron metabolism as a key regulator of CSCs. This review explores recent advances in iron metabolism in CSCs, conventional cancer therapies targeting iron biochemistry, therapeutic resistance in these cells, and potential treatment options that could overcome them. These findings provide important insights into therapeutic modalities against intractable cancers.

Potential Targets of Natural Products for Improving Cardiac Ischemic Injury: The Role of Nrf2 Signaling Transduction

Myocardial ischemia is the leading cause of health loss from cardiovascular disease worldwide. Myocardial ischemia and hypoxia during exercise trigger the risk of sudden exercise death which, in severe cases, will further lead to myocardial infarction. The Nrf2 transcription factor is an important antioxidant regulator that is extensively engaged in biological processes such as oxidative stress, inflammatory response, apoptosis, and mitochondrial malfunction. It has a significant role in the prevention and treatment of several cardiovascular illnesses, since it can control not only the expression of several antioxidant genes, but also the target genes of associated pathological processes. Therefore, targeting Nrf2 will have great potential in the treatment of myocardial ischemic injury. Natural products are widely used to treat myocardial ischemic diseases because of their few side effects. A large number of studies have shown that the Nrf2 transcription factor can be used as an important way for natural products to alleviate myocardial ischemia. However, the specific role and related mechanism of Nrf2 in mediating natural products in the treatment of myocardial ischemia is still unclear. Therefore, this review combs the key role and possible mechanism of Nrf2 in myocardial ischemic injury, and emphatically summarizes the significant role of natural products in treating myocardial ischemic symptoms, thus providing a broad foundation for clinical transformation.

Distinct mechanisms by which Nrf1 and Nrf2 as drug targets contribute to the anticancer efficacy of cisplatin on hepatoma cells

Cisplatin (cis-Dichlorodiamineplatinum[II], CDDP) is generally accepted as a platinum-based alkylating agent type of the DNA-damaging anticancer drug, which is widely administrated in clinical treatment of many solid tumors. The pharmacological effect of CDDP is mainly achieved by replacing the chloride ion (Cl-) in its structure with H2O to form active substances with the strong electrophilic properties and then react with any nucleophilic molecules, primarily leading to genomic DNA damage and subsequent cell death. In this process, those target genes driven by the consensus electrophilic and/or antioxidant response elements (EpREs/AREs) in their promoter regions are also activated or repressed by CDDP. Thereby, we here examined the expression profiling of such genes regulated by two principal antioxidant transcription factors Nrf1 and Nrf2 (both encoded by Nfe2l1 and Nfe2l2, respectively) in diverse cellular signaling responses to this intervention. The results demonstrated distinct cellular metabolisms, molecular pathways and signaling response mechanisms by which Nrf1 and Nrf2 as the drug targets differentially contribute to the anticancer efficacy of CDDP on hepatoma cells and xenograft tumor mice. Interestingly, the role of Nrf1, rather than Nrf2, is required for the anticancer effect of CDDP, to suppress malignant behavior of HepG2 cells by differentially monitoring multi-hierarchical signaling to gene regulatory networks. To our surprise, it was found there exists a closer relationship of Nrf1α than Nrf2 with DNA repair, but the hyperactive Nrf2 in Nrf1α-∕- cells manifests a strong correlation with its resistance to CDDP, albeit their mechanistic details remain elusive.

The novel β-TrCP protein isoform hidden in circular RNA confers trastuzumab resistance in HER2-positive breast cancer

Trastuzumab notably improves the outcome of human epidermal growth factor receptor 2 (HER2)-positive breast cancer patients, however, resistance to trastuzumab remains a major hurdle to clinical treatment. In the present study, we identify a circular RNA intimately linked to trastuzumab resistance. circ-β-TrCP, derived from the back-splicing of β-TrCP exon 7 and 13, confers trastuzumab resistance by regulating NRF2-mediated antioxidant pathway in a KEAP1-independent manner. Concretely, circ-β-TrCP encodes a novel truncated 343-amino acid peptide located in the nucleus, referred as β-TrCP-343aa, which competitively binds to NRF2, blocks SCFβ-TrCP-mediated NRF2 proteasomal degradation, and this protective effect of β-TrCP-343aa on NRF2 protein requires GSK3 activity. Subsequently, the elevated NRF2 transcriptionally upregulates a cohort of antioxidant genes, giving rise to trastuzumab resistance. Moreover, the translation ability of circ-β-TrCP is inhibited by eIF3j under both basal and oxidative stress conditions, and eIF3j is transcriptionally repressed by NRF2, thus forming a positive feedback circuit between β-TrCP-343aa and NRF2, expediting trastuzumab resistance. Collectively, our data demonstrate that circ-β-TrCP-encoded β-TrCP protein isoform drives HER2-targeted therapy resistance in a NRF2-dependent manner, which provides potential therapeutic targets for overcoming trastuzumab resistance.

The m5 C methyltransferase NSUN2 promotes codon-dependent oncogenic translation by stabilising tRNA in anaplastic thyroid cancer

BACKGROUND

Translation dysregulation plays a crucial role in tumourigenesis and cancer progression. Oncogenic translation relies on the stability and availability of tRNAs for protein synthesis, making them potential targets for cancer therapy.

METHODS

This study performed immunohistochemistry analysis to assess NSUN2 levels in thyroid cancer. Furthermore, to elucidate the impact of NSUN2 on anaplastic thyroid cancer (ATC) malignancy, phenotypic assays were conducted. Drug inhibition and time-dependent plots were employed to analyse drug resistance. Liquid chromatography-mass spectrometry and bisulphite sequencing were used to investigate the m5 C methylation of tRNA at both global and single-base levels. Puromycin intake and high-frequency codon reporter assays verified the protein translation level. By combining mRNA and ribosome profiling, a series of downstream proteins and codon usage bias were identified. The acquired data were further validated by tRNA sequencing.

RESULTS

This study observed that the tRNA m5 C methyltransferase NSUN2 was up-regulated in ATC and is associated with dedifferentiation. Furthermore, NSUN2 knockdown repressed ATC formation, proliferation, invasion and migration both in vivo and in vitro. Moreover, NSUN2 repression enhanced the sensitivity of ATC to genotoxic drugs. Mechanically, NSUN2 catalyses tRNA structure-related m5 C modification, stabilising tRNA that maintains homeostasis and rapidly transports amino acids, particularly leucine. This stable tRNA has a substantially increased efficiency necessary to support a pro-cancer translation program including c-Myc, BCL2, RAB31, JUNB and TRAF2. Additionally, the NSUN2-mediated variations in m5C levels and different tRNA Leu iso-decoder families, partially contribute to a codon-dependent translation bias. Surprisingly, targeting NSUN2 disrupted the c-Myc to NSUN2 cycle in ATC.

CONCLUSIONS

This research revealed that a pro-tumour m5C methyltransferase, dynamic tRNA stability regulation and downstream oncogenes, c-Myc, elicits a codon-dependent oncogenic translation network that enhances ATC growth and formation. Furthermore, it provides new opportunities for targeting translation reprogramming in cancer cells.

Deciphering the Mysterious Relationship between the Cross-Pathogenetic Mechanisms of Neurodegenerative and Oncological Diseases

The relationship between oncological pathologies and neurodegenerative disorders is extremely complex and is a topic of concern among a growing number of researchers around the world. In recent years, convincing scientific evidence has accumulated that indicates the contribution of a number of etiological factors and pathophysiological processes to the pathogenesis of these two fundamentally different diseases, thus demonstrating an intriguing relationship between oncology and neurodegeneration. In this review, we establish the general links between three intersecting aspects of oncological pathologies and neurodegenerative disorders, i.e., oxidative stress, epigenetic dysregulation, and metabolic dysfunction, examining each process in detail to establish an unusual epidemiological relationship. We also focus on reviewing the current trends in the research and the clinical application of the most promising chemical structures and therapeutic platforms that have a modulating effect on the above processes. Thus, our comprehensive analysis of the set of molecular determinants that have obvious cross-functional pathways in the pathogenesis of oncological and neurodegenerative diseases can help in the creation of advanced diagnostic tools and in the development of innovative pharmacological strategies.

Molecular mechanisms of ROS-modulated cancer chemoresistance and therapeutic strategies

Drug resistance is the main obstacle to achieving a cure in many cancer patients. Reactive oxygen species (ROS) are master regulators of cancer development that act through complex mechanisms. Remarkably, ROS levels and antioxidant content are typically higher in drug-resistant cancer cells than in non-resistant and normal cells, and have been shown to play a central role in modulating drug resistance. Therefore, determining the underlying functions of ROS in the modulation of drug resistance will contribute to develop therapies that sensitize cancer resistant cells by leveraging ROS modulation. In this review, we summarize the notable literature on the sources and regulation of ROS production and highlight the complex roles of ROS in cancer chemoresistance, encompassing transcription factor-mediated chemoresistance, maintenance of cancer stem cells, and their impact on the tumor microenvironment. We also discuss the potential of ROS-targeted therapies in overcoming tumor therapeutic resistance.

Multifaceted role of redox pattern in the tumor immune microenvironment regarding autophagy and apoptosis

The reversible oxidation-reduction homeostasis mechanism functions as a specific signal transduction system, eliciting related physiological responses. Disruptions to redox homeostasis can have negative consequences, including the potential for cancer development and progression, which are closely linked to a series of redox processes, such as adjustment of reactive oxygen species (ROS) levels and species, changes in antioxidant capacity, and differential effects of ROS on downstream cell fate and immune capacity. The tumor microenvironment (TME) exhibits a complex interplay between immunity and regulatory cell death, especially autophagy and apoptosis, which is crucially regulated by ROS. The present study aims to investigate the mechanism by which multi-source ROS affects apoptosis, autophagy, and the anti-tumor immune response in the TME and the mutual crosstalk between these three processes. Given the intricate role of ROS in controlling cell fate and immunity, we will further examine the relationship between traditional cancer therapy and ROS. It is worth noting that we will discuss some potential ROS-related treatment options for further future studies.

Radical oxygen species: an important breakthrough point for botanical drugs to regulate oxidative stress and treat the disorder of glycolipid metabolism

Background: The incidence of glycolipid metabolic diseases is extremely high worldwide, which greatly hinders people's life expectancy and patients' quality of life. Oxidative stress (OS) aggravates the development of diseases in glycolipid metabolism. Radical oxygen species (ROS) is a key factor in the signal transduction of OS, which can regulate cell apoptosis and contribute to inflammation. Currently, chemotherapies are the main method to treat disorders of glycolipid metabolism, but this can lead to drug resistance and damage to normal organs. Botanical drugs are an important source of new drugs. They are widely found in nature with availability, high practicality, and low cost. There is increasing evidence that herbal medicine has definite therapeutic effects on glycolipid metabolic diseases. Objective: This study aims to provide a valuable method for the treatment of glycolipid metabolic diseases with botanical drugs from the perspective of ROS regulation by botanical drugs and to further promote the development of effective drugs for the clinical treatment of glycolipid metabolic diseases. Methods: Using herb*, plant medicine, Chinese herbal medicine, phytochemicals, natural medicine, phytomedicine, plant extract, botanical drug, ROS, oxygen free radicals, oxygen radical, oxidizing agent, glucose and lipid metabolism, saccharometabolism, glycometabolism, lipid metabolism, blood glucose, lipoprotein, triglyceride, fatty liver, atherosclerosis, obesity, diabetes, dysglycemia, NAFLD, and DM as keywords or subject terms, relevant literature was retrieved from Web of Science and PubMed databases from 2013 to 2022 and was summarized. Results: Botanical drugs can regulate ROS by regulating mitochondrial function, endoplasmic reticulum, phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT), erythroid 2-related factor 2 (Nrf-2), nuclear factor κB (NF-κB), and other signaling pathways to improve OS and treat glucolipid metabolic diseases. Conclusion: The regulation of ROS by botanical drugs is multi-mechanism and multifaceted. Both cell studies and animal experiments have demonstrated the effectiveness of botanical drugs in the treatment of glycolipid metabolic diseases by regulating ROS. However, studies on safety need to be further improved, and more studies are needed to support the clinical application of botanical drugs.

Novel Role of Hemeoxygenase-1 in Phthalate-Induced Renal Proximal Tubule Cell Ferroptosis

Phthalates are widely used to improve the flexibility of poly(vinyl chloride) (PVC) polymer agriculture products. Di(2-ethylhexyl) phthalate (DEHP) is a type of addition to plastic and can lead to many health problems. Hemeoxygenase-1 (HO-1) is an extremely important molecule that releases enzymatic products to promote ferroptosis. This research aimed to explore the function of HO-1 in DEHP-induced renal proximal tubule cell ferroptosis. In the experiment, ICR male mice are exposed to (0, 50, 200, and 500 mg/kg BW/day) DEHP for 28 days. Here, we observed that DEHP induced glomeruli atrophy and the tubules swell. Furthermore, DEHP exposure could increase ferrous iron content and decrease antioxidant activity. We also found that DEHP exposure increased the expression of nuclear factor-erythroid 2 p45-related factor 2 (NFE2L2) in the nucleus. In particular, the expression of (HO-1) is significantly increased both in protein and mRNA levels. Glutathione peroxidase 4 (GPX4) as an endogenous control of ferroptosis was downregulated, which proved the occurrence of ferroptosis. In the study, exposure to DEHP activated the NFE2L2/HO-1 signaling pathway and resulted in ferroptosis of the proximal tubule. This research connects ferroptosis with HO-1, providing new insights into the potential roles of phthalates in nephrotoxicity.

Inhibitors of Keap1-Nrf2 protein-protein interaction reduce estrogen responsive gene expression and oxidative stress in estrogen receptor-positive breast cancer

Estrogen contributes to the development of breast cancer through estrogen receptor (ER) signaling and by generating genotoxic metabolites that cause oxidative DNA damage. To protect against oxidative stress, cells activate nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream cytoprotective genes that initiate antioxidant responses and detoxify xenobiotics. Nrf2 activation occurs by inhibiting the protein-protein interaction (PPI) between Nrf2 and its inhibitor Keap1, which otherwise targets Nrf2 for ubiquitination and destruction. In this study, we examined a series of novel direct inhibitors of Keap1-Nrf2 PPI in their role in promoting the availability of Nrf2 for antioxidant activity and attenuating estrogen-mediated responses in breast cancer. ER-positive human breast cancer cells MCF-7 were treated with 17β-estradiol (E2) in the presence or absence of selected Keap1-Nrf2 PPI inhibitors. Keap1-Nrf2 PPI inhibitors suppressed the mRNA and protein levels of estrogen responsive genes induced by E2 exposure, such as PGR. Keap1-Nrf2 PPI inhibitors caused significant activation of Nrf2 target genes. E2 decreased the mRNA and protein level of the Nrf2 target gene NQO1, and the Keap1-Nrf2 PPI inhibitors reversed this effect. The reversal of E2 action by these compounds was not due to binding to ER as ER antagonists. Further, a selected compound attenuated oxidative stress induced by E2, determined by the level of a biomarker 8-oxo-deoxyguanosine. These findings suggest that the Keap1-Nrf2 PPI inhibitors have potent antioxidant activity by activating Nrf2 pathways and inhibit E2-induced gene and protein expression. These compounds may serve as potential chemopreventive agents in estrogen-stimulated breast cancer.

Celastrol: The new dawn in the treatment of vascular remodeling diseases

Evidence is mounting that abnormal vascular remodeling leads to many cardiovascular diseases (CVDs). This suggests that vascular remodeling can be a crucial target for the prevention and treatment of CVDs. Recently, celastrol, an active ingredient of the broadly used Chinese herb Tripterygium wilfordii Hook F, has attracted extensive interest for its proven potential to improve vascular remodeling. Substantial evidence has shown that celastrol improves vascular remodeling by ameliorating inflammation, hyperproliferation, and migration of vascular smooth muscle cells, vascular calcification, endothelial dysfunction, extracellular matrix remodeling, and angiogenesis. Moreover, numerous reports have proven the positive effects of celastrol and its therapeutic promise in treating vascular remodeling diseases such as hypertension, atherosclerosis, and pulmonary artery hypertension. The present review summarizes and discusses the molecular mechanism of celastrol regulating vascular remodeling and provides preclinical proof for future clinical applications of celastrol.

Mechanism and application of ferroptosis in colorectal cancer

Colorectal cancer (CRC) is the third most common malignant tumor in the world. CRC has high morbidity and mortality rates and it is a serious threat to human health. Ferroptosis is a unique form of iron-dependent oxidative cell death that is usually accompanied by iron accumulation and lipid peroxidation. Ferroptosis has attracted worldwide attention since it was first proposed. It plays an important role in the development of a variety of diseases, such as tumors, ischemia/reperfusion injury, nervous system diseases, and kidney damage, and it may serve as a new therapeutic target. This article reviews the mechanism of ferroptosis and the possibility to target ferroptosis pathways in CRC, providing new ideas for the diagnosis and treatment of CRC.

Mogroside-rich extract from Siraitia grosvenorii fruits protects against heat stress-induced intestinal damage by ameliorating oxidative stress and inflammation in mice

Global warming makes humans and animals more vulnerable to heat stress. Heat stress can cause multiorgan dysfunction, especially in the intestine, primarily via oxidative stress and inflammation. Mogroside-rich extract (MGE) is the active ingredient of Siraitia grosvenorii and has significant antioxidant and anti-inflammatory activity. However, whether MGE can alleviate the intestinal damage caused by heat stress has not been explored. In this study, mice were given 600 mg kg^-1 MGE followed by exposure to high temperature (40 °C for 2 h per day), and the structures and molecular changes in the ileum were examined. Our findings showed that body weight was decreased by heat stress, while the activity of serum superoxide dismutase (SOD) was increased. We further found that heat stress impaired the intestinal barrier by reducing the number of goblet cells and mRNA levels of the tight junction proteins zona occludens protein 1 (ZO-1), Occludin (OCLD) and recombinant mucin 2 (MUC2 mucin), but it increased the mRNA level of trefoil factor 3 (TFF3). Interestingly, MGE treatment reversed these changes. Furthermore, heat stress increased the activity of SOD in the intestine, downregulated the expression of the oxidative stress-related genes glutathione peroxidase 1 (GPX1), SOD2 and nuclear factor erythroid 2-related factor 2 (NRF2), and upregulated the expression of catalase (CAT). Moreover, heat stress increased tumor necrosis factor-α (TNF-α) levels in the intestine and upregulated the expression of the inflammation-related genes interleukin 10 (IL-10), TNF-α, Interferon-γ (IFN-γ), toll like receptor 4 (TLR4) and nuclear factor-kappa B (NF-kB). However, MGE treatment effectively reduced TNF-α levels and restored the normal activity of SOD and normal mRNA levels for both oxidative stress-related and inflammation-related genes. In summary, our results showed that MGE can protect against heat stress-induced intestinal damage by ameliorating inflammation and oxidative stress.

Role of STAT3 and NRF2 in Tumors: Potential Targets for Antitumor Therapy

Signal transducer and activator of transcription 3 (STAT3) and nuclear factor erythroid-derived 2-like 2 (NRF2, also known as NFE2L2), are two of the most complicated transcription regulators, which participate in a variety of physiological processes. Numerous studies have shown that they are overactivated in multiple types of tumors. Interestingly, STAT3 and NRF2 can also interact with each other to regulate tumor progression. Hence, these two important transcription factors are considered key targets for developing a new class of antitumor drugs. This review summarizes the pivotal roles of the two transcription regulators and their interactions in the tumor microenvironment to identify potential antitumor drug targets and, ultimately, improve patients' health and survival.

Targeting oncogenic transcription factors in skin malignancies: An update on cancer stemness and therapeutic outcomes

The skin is the largest organ of the human body and prone to various diseases, including cancer; thus, provides the first line of defense against exogenous biological and non-biological agents. Skin cancer, a complex and heterogenic process, with steep incidence rate often metastasizes due to poor understanding of the underlying mechanisms of pathogenesis and clinical challenges. Indeed, accumulating evidence indicates that deregulation of transcription factors (TFs) due to genetic, epigenetic and signaling distortions plays essential role in the development of cutaneous malignancies and therapeutic challenges including cancer stemness features and reprogramming. This review highlights the recent developments exploring underlying mechanisms how deregulated TFs (e.g., NF-κB, AP-1, STAT etc.,) orchestrates cutaneous onco-pathogenesis, reprogramming, stemness and poor clinical outcomes. Along this line, bioactive drugs, and their derivatives from natural and or synthetic origin has gained attention due to their multitargeting potential, potentially safer and effective therapeutic outcome for human malignancies. We also discussed therapeutic importance of targeting aberrantly expressed TFs in skin cancers with bioactive natural products and or synthetic agents.

Nrf2 and Oxidative Stress: A General Overview of Mechanisms and Implications in Human Disease

Organisms are continually exposed to exogenous and endogenous sources of reactive oxygen species (ROS) and other oxidants that have both beneficial and deleterious effects on the cell. ROS have important roles in a wide range of physiological processes; however, high ROS levels are associated with oxidative stress and disease progression. Oxidative stress has been implicated in nearly all major human diseases, from neurogenerative diseases and neuropsychiatric disorders to cardiovascular disease, diabetes, and cancer. Antioxidant defence systems have evolved as a means of protection against oxidative stress, with the transcription factor Nrf2 as the key regulator. Nrf2 is responsible for regulating an extensive panel of antioxidant enzymes involved in the detoxification and elimination of oxidative stress and has been extensively studied in the disease contexts. This review aims to provide the reader with a general overview of oxidative stress and Nrf2, including basic mechanisms of Nrf2 activation and regulation, and implications in various major human diseases.

The molecular activity of cannabidiol in the regulation of Nrf2 system interacting with NF-κB pathway under oxidative stress

Cannabidiol (CBD), the major non-psychoactive phytocannabinoid of Cannabis sativa L., is one of the most studied compounds in pharmacotherapeutic approaches to treat oxidative stress-related diseases such as cardiovascular, metabolic, neurodegenerative, and neoplastic diseases. The literature data to date indicate the possibility of both antioxidant and pro-oxidative effects of CBD. Thus, the mechanism of action of this natural compound in the regulation of nuclear factor 2 associated with erythroid 2 (Nrf2), which plays the role of the main cytoprotective regulator of redox balance and inflammation under oxidative stress conditions, seems to be particularly important. Moreover, Nrf2 is strongly correlated with the cellular neoplastic profile and malignancy, which in turn is critical in determining the cellular response induced by CBD under pathophysiological conditions. This paper summarizes the CBD-mediated pathways of regulation of the Nrf2 system by altering the expression and modification of both proteins directly involved in Nrf2 transcriptional activity and proteins involved in the relationship between Nrf2 and the nuclear factor kappa B (NF-κB) which is another redox-sensitive transcription factor.

[Progress of NRF2 Signaling Pathway in Promoting Proliferation of Non-small Cell Lung Cancer]

The morbidity and mortality of lung cancer ranks among the top cancers in the world. Non-small cell lung cancer (NSCLC) is the main pathological type of lung cancer, with limited treatment options and poor prognosis. The nuclear factor E2-related factor 2 (NRF2) signaling pathway is highly mutated and activated in NSCLC, and promotes the malignant progression of lung cancer through various mechanisms. NRF2-targeted therapy will provide new treatment strategies for patients with NSCLC. This article will review the basic structure and response pathways of the NRF2 pathway, the mechanism of NRF2 regulating lung cancer cell proliferation, and the research and development progress of NRF2 inhibitors.
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Delicaflavone Represses Lung Cancer Growth by Activating Antitumor Immune Response through N6-Methyladenosine Transferases and Oxidative Stress

Our previous studies have shown that delicaflavone (DLL), a biocomponent extracted from Selaginella doederleinii Hieron, has antitumor activity. However, the role of DLL in the antitumor immune response is unknown. In this study, we tested the potential roles of DLL in antitumor immune response. An animal tumor model with Lewis lung cancer cell line (3LL) in C57BL/6 mice was established to determine whether DLL induced the tumor-bearing host's antitumor immune response. m6A-MeRIP-qPCR, western blot, and flow cytometry were performed to explore the underlying mechanisms. DLL inhibited the proliferation of 3LL lung cancer cells in vitro and in vivo and induced tumor cell oxidative stress. DLL significantly inhibited tumor growth in immunocompetent mice compared with nude mice. DLL treatment significantly increased Th1 cytokine production and CD8+ T cell infiltration into tumor tissues in tumor-bearing mice. DLL-mediated antitumor immune effects were reversed by overexpression of the N6-methyladenosine (m6A) transferase Mettl3/Mettl14. Mechanistically, DLL upregulated the expression of Stat1 and Irf1 and the secretion of cytokines by inhibiting Mettl3 and Mettl14 in lung cancer cells. In conclusion, DLL inhibited lung cancer cell growth by suppressing Mettl3/Mettl14 to activate antitumor immunity. These findings provided an opportunity to enhance lung cancer immunotherapy.

N-Acetylcysteine Promotes Metastatic Spread of Melanoma in Mice

Simple Summary

Malignant melanoma is a cancer derived from melanocytes, the cells that produce pigment (melanin) in the skin. It develops on the skin, but can also appear on the mucous membranes and in other locations. Melanomas are responsible for 80% of deaths related to skin cancers. In recent years, the number of cases has increased alarmingly, likely in relation to sun exposure habits. Once melanoma spreads to distant parts of the body, the 5-year survival rate is about 10%. N-acetylcysteine (NAC) is a drug with antioxidant properties, and thereby could play a role in preventing cancer. NAC is commonly used as a mucolytic in different respiratory diseases, to treat acetaminophen (Tylenol) poisoning, and is also present in different nutritional supplements. Nevertheless, the use of NAC and other antioxidants in cancer has been questioned. Here, we show that high therapeutic doses of NAC may cause metastatic spread of a malignant melanoma.

Abstract

N-acetylcysteine (NAC) is a direct Cys donor and a promoter of glutathione (GSH) synthesis. GSH regulates melanoma growth and NAC has been suggested to increase melanoma metastases in mice. We found that high therapeutic doses of NAC do not increase the growth of melanoma xenografts, but can cause metastatic spread and distant metastases. Nevertheless, this is not due to an antioxidant effect since NAC, in fact, increases the generation of reactive oxygen species in the growing metastatic melanoma. Trolox, an antioxidant vitamin E derivative, administered in vivo, decreased metastatic growth. Metastatic cells isolated from NAC-treated mice showed an increase in the nuclear translocation of Nrf2, as compared to controls. Nrf2, a master regulator of the antioxidant response, controls the expression of different antioxidant enzymes and of the γ-glutamylcysteine ligase (the rate-limiting step in GSH synthesis). Cystine uptake through the xCT cystine-glutamate antiporter (generating intracellular Cys) and the γ-glutamylcysteine ligase activity are key to control metastatic growth. This is associated to an increase in the utilization of L-Gln by the metastatic cells, another metastases promoter. Our results demonstrate the potential of NAC as an inducer of melanoma metastases spread, and suggest that caution should be taken when administering GSH promoters to cancer patients.

Prevention and treatment of natural products from Traditional Chinese Medicine in depression: Potential targets and mechanisms of action

The molecular pathology involved in the development of depression is complex. Many signaling pathways and transcription factors have been demonstrated to display crucial roles in the process of depression occurrence and development. The multi-components and multi-targets of Traditional Chinese Medicine (TCM) are uniquely advantageous in the prevention and treatment of chronic diseases. This review summarizes the pharmacological regulations of natural products from TCM in the prevention and treatment of depression from the aspects of transcription factors (CREB, NF-κB, Nrf2) and molecular signaling pathways (BDNF-TrkB, MAPK, GSK-3β, TLR-4).

The Potential Key Role of the NRF2/NQO1 Pathway in the Health Effects of Arsenic Pollution on SCC

Arsenic is widely present in nature and is a common environmental poison that seriously damages human health. Chronic exposure to arsenic is a major environmental poisoning factor that promotes cell proliferation and leads to malignant transformation. However, its molecular mechanism remains unclear. In this study, we found that arsenite can promote the transformation of immortalized human keratinocyte cells (HaCaT) from the G0/G1 phase to S phase and demonstrated malignant phenotypes. This phenomenon is accompanied by obviously elevated levels of NRF2, NQO1, Cyclin E, and Cyclin-dependent kinase 2 (CDK2). Silencing the NRF2 expression with small interfering RNA (siRNA) in arsenite-transformed (T-HaCaT) cells was shown to reverse the malignant phenotype. Furthermore, the siRNA silencing of NQO1 significantly decreased the levels of the cyclin E-CDK2 complex, inhibiting the G0/G1 to S phase cell cycle progression and transformation to the T-HaCaT phenotypes. Thus, we hypothesized that the NRF2/NQO1 pathway played a key role in the arsenite-induced malignancy of HaCaT cells. By increasing the expression of Cyclin E-CDK2, the NRF2/NQO1 pathway can affect cell cycle progression and cell proliferation. A new common health effect mechanism of arsenic carcinogenesis has been identified; thus, it would contribute to the development of novel treatments to prevent and treat skin cancer caused by arsenic.

CHML is an NRF2 target gene that regulates mTOR function

The transcription factor nuclear factor erythroid 2-related factor 2 (NRF2) is often highly expressed in non-small cell lung cancer (NSCLC). Through its target genes, NRF2 enhances cancer progression and chemo/radioresistance, leading to a poorer prognosis in patients with high NRF2 expression. In this study, we identified CHM-like Rab escort protein (CHML; encoding Rep2) as an NRF2 target gene with an antioxidant response element (ARE) in its promoter region (-1622 to -1612). Analysis of patient data curated by The Cancer Genome Atlas (TCGA) and Oncomine databases revealed that CHML mRNA expression was elevated in lung adenocarcinoma (LUAD) patient tumor tissues and correlated with decreased patient survival. Immunohistochemistry (IHC) analysis of normal versus lung cancer patient tissues revealed that Rep2 protein levels were higher in lung tumors compared with normal tissue, which also correlated with increased levels of NRF2. Importantly, siRNA-mediated knockdown of CHML/Rep2 in A549 NSCLC cells decreased their ability to proliferate. Mechanistically, Rep2 mediates mTOR function, as loss of Rep2 inhibited, whereas overexpression enhanced, mTOR translocation and activation at the lysosome. Our findings identify a novel NRF2-Rep2-dependent regulation of mTOR function.

Therapeutic Influence on Important Targets Associated with Chronic Inflammation and Oxidative Stress in Cancer Treatment

Chronic inflammation and oxidative stress are the interconnected pathological processes, which lead to cancer initiation and progression. The growing level of oxidative and inflammatory damage was shown to increase cancer severity and contribute to tumor spread. The overproduction of reactive oxygen species (ROS), which is associated with the reduced capacity of the endogenous cell defense mechanisms and/or metabolic imbalance, is the main contributor to oxidative stress. An abnormal level of ROS was defined as a predisposing factor for the cell transformation that could trigger pro-oncogenic signaling pathways, induce changes in gene expression, and facilitate accumulation of mutations, DNA damage, and genomic instability. Additionally, the activation of transcription factors caused by a prolonged oxidative stress, including NF-κB, p53, HIF1α, etc., leads to the expression of several genes responsible for inflammation. The resulting hyperactivation of inflammatory mediators, including TNFα, TGF-β, interleukins, and prostaglandins can contribute to the development of neoplasia. Pro-inflammatory cytokines were shown to trigger adaptive reactions and the acquisition of resistance by tumor cells to apoptosis, while promoting proliferation, invasion, and angiogenesis. Moreover, the chronic inflammatory response leads to the excessive production of free radicals, which further aggravate the initiated reactions. This review summarizes the recent data and progress in the discovery of mechanisms that associate oxidative stress and chronic inflammation with cancer onset and metastasis. In addition, the review provides insights for the development of therapeutic approaches and the discovery of natural substances that will be able to simultaneously inhibit several key oncological and inflammation-related targets.

Genetic and epigenetic regulation of the NRF2-KEAP1 pathway in human lung cancer

Electrophilic and oxidative stress is caused when homeostatic mechanisms are disrupted. A major defense mechanism involves the activation of the nuclear factor erythroid 2-related factor 2 (NRF2) transcription factor encoded by the NFE2L2 gene, which can accelerate the detoxification of electrophilic carcinogens and prevent cancer and on the other hand in certain exposure contexts may exacerbate the carcinogenic process. NRF2-target genes activated under these conditions can be used as biomarkers of stress signalling, while activation of NRF2 can also reveal the epigenetic mechanisms that modulate NFE2L2 expression. Epigenetic mechanisms that regulate NFE2L2 and the gene for its adaptor protein KEAP1 include DNA methylation, histone modifications and microRNA. Understanding the activation of the NRF2-KEAP1 signalling pathway in human lung cancer, its epigenetic regulation and its role in oncogenesis is the subject of this review.

New Look of EBV LMP1 Signaling Landscape

Simple Summary

Epstein-Barr Virus (EBV) infection is associated with various lymphomas and carcinomas as well as other diseases in humans. The transmembrane protein LMP1 plays versatile roles in EBV life cycle and pathogenesis, by perturbing, reprograming, and regulating a large range of host cellular mechanisms and functions, which have been increasingly disclosed but not fully understood so far. We summarize recent research progress on LMP1 signaling, including the novel components LIMD1, p62, and LUBAC in LMP1 signalosome and LMP1 novel functions, such as its induction of p62-mediated selective autophagy, regulation of metabolism, induction of extracellular vehicles, and activation of NRF2-mediated antioxidative defense. A comprehensive understanding of LMP1 signal transduction and functions may allow us to leverage these LMP1-regulated cellular mechanisms for clinical purposes.

Abstract

The Epstein–Barr Virus (EBV) principal oncoprotein Latent Membrane Protein 1 (LMP1) is a member of the Tumor Necrosis Factor Receptor (TNFR) superfamily with constitutive activity. LMP1 shares many features with Pathogen Recognition Receptors (PRRs), including the use of TRAFs, adaptors, and kinase cascades, for signal transduction leading to the activation of NFκB, AP1, and Akt, as well as a subset of IRFs and likely the master antioxidative transcription factor NRF2, which we have gradually added to the list. In recent years, we have discovered the Linear UBiquitin Assembly Complex (LUBAC), the adaptor protein LIMD1, and the ubiquitin sensor and signaling hub p62, as novel components of LMP1 signalosome. Functionally, LMP1 is a pleiotropic factor that reprograms, balances, and perturbs a large spectrum of cellular mechanisms, including the ubiquitin machinery, metabolism, epigenetics, DNA damage response, extracellular vehicles, immune defenses, and telomere elongation, to promote oncogenic transformation, cell proliferation and survival, anchorage-independent cell growth, angiogenesis, and metastasis and invasion, as well as the development of the tumor microenvironment. We have recently shown that LMP1 induces p62-mediated selective autophagy in EBV latency, at least by contributing to the induction of p62 expression, and Reactive Oxygen Species (ROS) production. We have also been collecting evidence supporting the hypothesis that LMP1 activates the Keap1-NRF2 pathway, which serves as the key antioxidative defense mechanism. Last but not least, our preliminary data shows that LMP1 is associated with the deregulation of cGAS-STING DNA sensing pathway in EBV latency. A comprehensive understanding of the LMP1 signaling landscape is essential for identifying potential targets for the development of novel strategies towards targeted therapeutic applications.