NOX4 functions as a mitochondrial energetic sensor coupling cancer metabolic reprogramming to drug resistance

NOX4 as an emerging prognostic and immunological biomarker across pan-cancer analyses

Despite extensive research highlighting the pivotal role of NOX4 in the development of various malignancies, no systematic pan-cancer analysis has been conducted to evaluate its comprehensive prognostic value and potential immunological functions. In this study, we explored the prognostic significance of NOX4 and its role in immune modulation across different cancer types. We performed a pan-cancer analysis of NOX4 expression and its prognostic implications using multiple databases, including TCGA, GEPIA, GTEx, UALCAN, TISCH, GDSC, PDB, TIMER, and cBioPortal. This analysis provided a detailed assessment of NOX4 expression profiles, clinical correlations, genetic variants, tumor microenvironment interactions, immune relevance, therapeutic potential, and related gene functions through various multi-omics approaches. To further investigate these findings, we collected clinical samples from selected cancer types and validated NOX4 expression through immunohistochemistry, H&E staining, and RT-PCR. Our results revealed that NOX4 was overexpressed in most tumors, although its expression was significantly reduced in certain renal cancers. Moreover, we observed distinct correlations between NOX4 expression and patient prognosis. Notably, NOX4 expression was significantly associated with tumor infiltration, indicating its potential as a target for immunotherapy. Additionally, NOX4 expression showed significant correlations with immune checkpoint proteins (ICP), tumor mutation burden (TMB), microsatellite instability (MSI), RNA stemness scores (RNAss), DNA stemness scores (DNAss), RNA methylation, and DNA methylation.

Reactive oxygen species-dependent nanomedicine therapeutic modalities for gastric cancer

Reactive oxygen species (ROS) play a double-edged role in gastric cancer (GC). Higher levels of ROS in tumor cells compared to normal cells facilitate tumor progression. Once ROS concentrations rise rapidly to toxic levels, they cause GC cell death, which is instead beneficial for GC treatment. Based on these functions, nano-delivery systems taking the therapeutic advantages of ROS have been widely employed in tumor therapy in recent years, overcoming the drawbacks of conventional drug delivery techniques, such as non-specific systemic effects. In this review, the precise impacts of ROS on GC have been detailed, along with ROS-based nanomedicine therapeutic schemes. These strategies mainly focused on the use of excess ROS in the tumor microenvironment for controlled drug release and a substantial enhancement of ROS concentrations for tumor killing. The challenges and opportunities for the advancement of these anticancer therapies are also emphasized.

Dual inhibition of oxidative phosphorylation and glycolysis using a hyaluronic acid nanoparticle NOX inhibitor enhanced response to radiotherapy in colorectal cancer

Metabolic reprogramming characterized by mitochondrial dysfunction and increased glycolysis is associated with aggressive tumor biology and poor therapeutic response. The interplays among NADPH oxidase (NOX)-mediated reactive oxygen species, regulation of glycolysis and oxidative phosphorylation (OXPHOS) in cancer cells suggest an opportunity to develop a new cancer therapy. We found that treatment with a hyaluronic acid nanoparticle encapsulated with GKT831 (HANP/GKT831), a NOX1/4 inhibitor, markedly inhibited the proliferation and invasion of cancer cells. Treated tumor cells had reduced levels of mitochondrial ROS, glycolysis, and OXPHOS. The combination of HANP/GKT831 with radiation reduced colony formation and invasion of tumor cells. The combination therapy markedly inhibited the levels of molecules in glycolysis, OXPHOS, and DNA repairing pathways in tumor cells. Systemic administrations of HANP/GKT831 combined with radiotherapy significantly inhibited tumor growth by 84.7 % in a mouse colorectal tumor model. Tumors treated with HANP/GKT831 and radiation had increased DNA damage and apoptotic cell death. Furthermore, the combined therapy increased intratumoral infiltration of activated cytotoxic T cells and M1 macrophages but reduced the levels of immunosuppressive fibroblasts and M2 macrophages. Our results support HANP/GKT831 as a cancer nanotherapeutic agent that induces redox and bioenergy stresses in cancer cells for enhanced therapeutic response to radiotherapy.

Nitazoxanide Modulates Mitochondrial Function and Inflammatory Metabolism in Chondrocytes from Patients with Osteoarthritis via AMPK/mTORC1 Signaling

Osteoarthritis (OA) is a long-term degenerative condition of the joints, characterized by persistent inflammation, progressive cartilage breakdown, and impaired mitochondrial function. Recent studies have shown that hyperactivation of the mTORC1 pathway and metabolic reprogramming of chondrocytes contribute to disease progression. Nitazoxanide (NTZ), an oral antiparasitic agent approved by the Food and Drug Administration, has shown anti-inflammatory and mitochondrial protective effects in various disease situations; despite this, its application in osteoarthritis has yet to be fully investigated. Here, we assessed the therapeutic efficacy of NTZ using IL-1β-stimulated primary chondrocytes derived from patients with OA. NTZ substantially reduced the expression of proinflammatory cytokines and matrix metalloproteinases, restored mitochondrial membrane potential, and reduced mitochondrial reactive oxygen species levels. NTZ also effectively reversed IL-1β-induced glycolytic metabolic changes by inhibiting glucose uptake and GLUT1 expression. Mechanistically, NTZ inhibited the activation of the mTORC1 pathway and substantially increased AMPK phosphorylation. The siRNA-mediated AMPK knockdown negated NTZ-induced mitochondrial and metabolic improvements, suggesting that AMPK is a key upstream regulator of the protective actions of NTZ. NTZ can, therefore, effectively inhibit inflammatory metabolic reprogramming and mitochondrial dysfunction in OA chondrocytes through AMPK-dependent mTORC1 signaling inhibition, highlighting its potential as a disease-modifying therapy for OA.

Warburg effect and lactylation in cancer: mechanisms for chemoresistance

In the clinical management of cancers, the emergence of chemoresistance represents a profound and imperative "pain point" that requires immediate attention. Understanding the mechanisms of chemoresistance is essential for developing effective therapeutic strategies. Importantly, existing studies have demonstrated that glucose metabolic reprogramming, commonly referred to as the Warburg effect or aerobic glycolysis, is a major contributor to chemoresistance. Additionally, lactate, a byproduct of aerobic glycolysis, functions as a signaling molecule that supports lysine lactylation modification of proteins, which also plays a critical role in chemoresistance. However, it is insufficient to discuss the role of glycolysis or lactylation in chemoresistance from a single perspective. The intricate relationship between aerobic glycolysis and lactylation plays a crucial role in promoting chemoresistance. Thus, a thorough elucidation of the mechanisms underlying chemoresistance mediated by aerobic glycolysis and lactylation is essential. This review provides a comprehensive overview of these mechanisms and further outlines that glycolysis and lactylation exert synergistic effects, promoting the development of chemoresistance and creating a positive feedback loop that continues to mediate this resistance. The close link between aerobic glycolysis and lactylation suggests that the application of glycolysis-related drugs or inhibitors in cancer therapy may represent a promising anticancer strategy. Furthermore, the targeted application of lactylation, either alone or in combination with other treatments, may offer new therapeutic avenues for overcoming chemoresistance.

The Role of mtDNA Mutations in Atherosclerosis: The Influence of Mitochondrial Dysfunction on Macrophage Polarization

Atherosclerosis is a complex inflammatory process associated with high-mortality cardiovascular diseases. Today, there is a growing body of evidence linking atherosclerosis to mutations of mitochondrial DNA (mtDNA). But the mechanism of this link is insufficiently studied. Atherosclerosis progression involves different cell types and macrophages are one of the most important. Due to their high plasticity, macrophages can demonstrate pro-inflammatory and pro-atherogenic (macrophage type M1) or anti-inflammatory and anti-atherogenic (macrophage type M2) effects. These two cell types, formed as a result of external stimuli, differ significantly in their metabolic profile, which suggests the central role of mitochondria in the implementation of the macrophage polarization route. According to this, we assume that mtDNA mutations causing mitochondrial disturbances can play the role of an internal trigger, leading to the formation of macrophage M1 or M2. This review provides a comparative analysis of the characteristics of mitochondrial function in different types of macrophages and their possible associations with mtDNA mutations linked with inflammation-based pathologies including atherosclerosis.

Short-term aerobic exercise prevents development of glucocorticoid myopathic features in aged skeletal muscle in a sex-dependent manner

Older adults are vulnerable to glucocorticoid-induced muscle atrophy and weakness, with sex potentially influencing their susceptibility to those effects. Aerobic exercise can reduce glucocorticoid-induced muscle atrophy in young rodents. However, it is unknown whether aerobic exercise can prevent glucocorticoid myopathy in aged muscle. The objectives of this study were to define the extent to which sex influences the development of glucocorticoid myopathy in aged muscle, and to determine the extent to which aerobic exercise training protects against myopathy development. Twenty-four-month-old female (n = 30) and male (n = 33) mice were randomized to either sedentary or aerobic exercise groups. Within their respective groups, mice were randomized to either daily treatment with dexamethasone (DEX) or saline. Upon completing treatments, the contractile properties of the triceps surae complex were assessed in situ. DEX marginally lowered muscle mass and soluble protein content in both sexes, which was attenuated by aerobic exercise only in females. DEX increased sub-tetanic force and rate of force development only in females, which was not influenced by aerobic exercise. Muscle fatigue was higher in both sexes following DEX, but aerobic exercise prevented fatigue induction only in females. The sex-specific differences to muscle function in response to DEX treatment coincided with sex-specific changes to the content of proteins related to calcium handling, mitochondrial quality control, reactive oxygen species production, and glucocorticoid receptor in muscle. These findings define several important sexually dimorphic changes to aged skeletal muscle physiology in response to glucocorticoid treatment and define the capacity of short-term aerobic exercise to protect against those changes. KEY POINTS: There are sexually dimorphic effects of glucocorticoids on aged skeletal muscle physiology. Glucocorticoid-induced changes to aged muscle contractile properties coincide with sex-specific differences in the content of calcium handling proteins. Aerobic exercise prevents glucocorticoid-induced fatigue only in aged females and coincides with differences in the content of mitochondrial quality control proteins and glucocorticoid receptors.

Anti-Inflammatory and Anticancer Effects of Kaurenoic Acid in Overcoming Radioresistance in Breast Cancer Radiotherapy

Background/Objectives: Peroxisome proliferator-activated receptor γ (PPARγ) plays a key role in mediating anti-inflammatory and anticancer effects in the tumor microenvironment. Kaurenoic acid (KA), a diterpene compound isolated from Sphagneticola trilobata (L.) Pruski, has been demonstrated to exert anti-inflammatory, anticancer, and antihuman immunodeficiency virus effects. Methods: In this study, we identified KA as a novel activator of PPARγ with potent anti-inflammatory and antitumor effects both in vitro and in vivo. Given the potential of PPARγ regulators in overcoming radioresistance and chemoresistance in cancer therapies, we hypothesized that KA may enhance the efficacy of breast cancer radiotherapy. Results: In a lipopolysaccharide (LPS)-induced mouse inflammation model, KA treatment reduced the levels of pro-inflammatory cytokines, including COX-2, IL-6, IL-1β, and TNFα. In a xenograft mouse mode of breast cancer, KA treatment inhibited tumor growth. Specifically, KA treatment enhanced caspase-3 activity and cytotoxicity against MDA-MB-231 and MCF-7 breast cancer cells. When KA was co-treated with a caspase inhibitor, Z-VAD-FMK, caspase-dependent apoptosis was suppressed in these cells. KA was found to induce the generation of cytosolic calcium ions (Ca2+) and reactive oxygen species (ROS), triggering endoplasmic reticulum (ER) stress via the PERK-ATF4-CHOP axis. Hence, the ER stressor thapsigargin (TG) synergized with KA treatment to enhance apoptosis in these cells, while the loss of the PERK or CHOP function inhibited this phenomenon. KA treatment was shown to induce oxidative stress via the NADPH oxidase 4 (NOX4) and stimulate ROS production. Specifically, NOX4 knockdown (KD) and antioxidant treatment (N-acetyl cysteine or diphenyleneiodonium) suppressed such ER stress-mediated apoptosis by inhibiting KA-enhanced caspase-3 activity, cytotoxicity, and intracellular ROS production in the treated cells. In radioresistant MDA-MB-231R and MCF-7R cells, KA combined with 2 Gy radiation overcame radioresistance by upregulating PPARγ and modulating epithelial-mesenchymal transition (EMT) markers, such as E-cadherin, N-cadherin, and vimentin. In PPARγ KD MDA-MB-231R and MCF-7R cells, this phenomenon was inhibited due to reduced PPARγ and NOX4 expression. Conclusions: In conclusion, these findings demonstrated KA as a novel PPARγ regulator with promising potential to enhance the efficacy of breast cancer radiotherapy.

Podocyte SIRPα reduction in diabetic nephropathy aggravates podocyte injury by promoting pyruvate kinase M2 nuclear translocation

Podocyte injury is a critical event in the pathogenesis of diabetic nephropathy (DN). Hyperglycemia, oxidative stress, inflammation, and other factors contribute to podocyte damage in DN. In this study, we demonstrate that signaling regulatory protein alpha (SIRPα) plays a pivotal role in regulating the metabolic and immune homeostasis of podocytes. Deletion of SIRPα in podocytes exacerbates, while transgenic overexpression of SIRPα alleviates, podocyte injury in experimental DN mice. Mechanistically, SIRPα downregulation promotes pyruvate kinase M2 (PKM2) phosphorylation, initiating a positive feedback loop that involves PKM2 nuclear translocation, NF-κB activation, and oxidative stress, ultimately impairing aerobic glycolysis. Consistent with this mechanism, shikonin ameliorates podocyte injury by reducing PKM2 nuclear translocation, preventing oxidative stress and NF-κB activation, thereby restoring aerobic glycolysis.

Role of reactive oxygen species in regulating epigenetic modifications

Reactive oxygen species (ROS) originate from diverse sources and regulate multiple signaling pathways within the cellular environment. Their generation is intricately controlled, and disruptions in their signaling or atypical levels can precipitate pathological conditions. Epigenetics, the examination of heritable alterations in gene expression independent of changes in the genetic code, has been implicated in the pathogenesis of various diseases through aberrant epigenetic modifications. The significant contribution of epigenetic modifications to disease progression underscores their potential as crucial therapeutic targets for a wide array of medical conditions. This study begins by providing an overview of ROS and epigenetics, followed by a discussion on the mechanisms of epigenetic modifications such as DNA methylation, histone modification, and RNA modification-mediated regulation. Subsequently, a detailed examination of the interaction between ROS and epigenetic modifications is presented, offering new perspectives and avenues for exploring the mechanisms underlying specific epigenetic diseases and the development of novel therapeutics.

Ubiquitination in osteosarcoma: unveiling the impact on cell biology and therapeutic strategies

Ubiquitination, a multifaceted post-translational modification, regulates protein function, degradation, and gene expression. The pivotal role of ubiquitination in the pathogenesis and progression of cancer, including colorectal, breast, and liver cancer, is well-established. Osteosarcoma, an aggressive bone tumor predominantly affecting adolescents, also exhibits dysregulation of the ubiquitination system, encompassing both ubiquitination and deubiquitination processes. This dysregulation is now recognized as a key driver of osteosarcoma development, progression, and chemoresistance. This review highlights recent progress in elucidating how ubiquitination modulates tumor behavior across signaling pathways. We then focus on the mechanisms by which ubiquitination influences osteosarcoma cell function. Finally, we discuss the potential for targeting the ubiquitin-proteasome system in osteosarcoma therapy. By unraveling the impact of ubiquitination on osteosarcoma cell physiology, we aim to facilitate the development of novel strategies for prognosis, staging, treatment, and overcoming chemoresistance.

Prognostic Prediction and Immune Microenvironment Characterization in Uveal Melanoma: A Novel Mitochondrial Metabolism-Related Gene Signature

Uveal Melanoma (UM), a highly aggressive and metastatic intraocular cancer with a strong propensity for liver metastasis, presents limited therapeutic alternatives and unfavorable survival outcomes. Despite its low incidence, the underlying mechanisms of UM pathogenesis and the precise role of mitochondrial metabolism in UM remain inadequately understood. Utilizing Cox proportional hazards regression analysis was used to assess prognostic relevance, and consensus clustering was employed for molecular subtyping. A risk signature was constructed using Least Absolute Shrinkage and Selection Operator (LASSO) Cox regression. We further conducted comparative analyses on clinicopathological characteristics, somatic mutation profiles, drug sensitivity, gene expression patterns, and tumor microenvironment features across different molecular subtypes. Moreover, a nomogram was developed and evaluated. Among 1234 mitochondria metabolism-related genes (MMRGs), 343 were identified as significantly associated with the prognosis of UM. These prognosis-associated MMRGs facilitated the classification of UM into two distinct molecular subtypes, which displayed notable differences in prognosis and pathological staging. Furthermore, an index termed the MMRGs-derived index (MMI) was derived from eight MMRGs, serving as a quantitative measure for poor prognosis risk in UM. MMI demonstrated significant associations with clinicopathological characteristics, somatic mutations, drug responsiveness, and the tumor microenvironment, where higher MMI levels corresponded to worse prognosis, advanced pathological stages, and increased immune cell infiltration. The nomogram built upon MMI provided a potential tool for clinical prognosis assessment in UM patients. This study demonstrated the potential value of MMRGs in predicting prognosis and molecular stratification within UM; however, additional clinical and basic research is warranted to validate their applicability and elucidate the related mechanisms.

Exploring NADPH oxidases 2 and 4 in cardiac and skeletal muscle adaptations - A cross-tissue comparison

Striated muscle cells, encompassing cardiac myocytes and skeletal muscle fibers, are fundamental to athletic performance, facilitating blood circulation and coordinated movement through contraction. Despite their distinct functional roles, these muscle types exhibit similarities in cytoarchitecture, protein expression, and excitation-contraction coupling. Both muscle types also undergo molecular remodeling in energy metabolism and cell size in response to acute and repeated exercise stimuli to enhance exercise performance. Reactive oxygen species (ROS) produced by NADPH oxidase (NOX) isoforms 2 and 4 have emerged as signaling molecules that regulate exercise adaptations. This review systematically compares NOX2 and NOX4 expression, regulation, and roles in cardiac and skeletal muscle responses across exercise modalities. We highlight the many gaps in our knowledge and opportunities to let future skeletal muscle research into NOX-dependent mechanisms be inspired by cardiac muscle studies and vice versa. Understanding these processes could enhance the development of exercise routines to optimize human performance and health strategies that capitalize on the advantages of physical activity.

Furanodienone induces apoptosis via regulating the PRDX1/MAPKs/p53/caspases signaling axis through NOX4-derived mitochondrial ROS in colorectal cancer cells

Furanodienone, a biologically active constituent of sesquiterpenes isolated from Rhizome Curcumae, has been reported to induce apoptosis in human colorectal cancer (CRC) cells by promoting the generation of reactive oxygen species (ROS). However, the source of ROS and how it manipulates apoptosis in CRC cells remains to be elucidated. Herein, we assessed the potential role of the well-known sources of intracellular ROS-mitochondrial electron transport chain and the nicotinamide adenine dinucleotide phosphate oxidases (NOXs), on furanodienone-induced cell death. The results indicated that furanodienone substantially increased the levels of mitochondrial ROS, which were subsequently eliminated by the general NOX inhibitor. Specifically, the nuclear factor kappa-B (NF-κB) translocation triggered a significant rise in the expression of NOX4, an isoform of the NOXs family, upon furanodienone treatment. Nevertheless, the specific NOX4 inhibitor GLX351322 attenuated cell apoptosis and mitochondrial ROS production. As a result, ROS burst induced by furanodienone suppressed the expression of peroxiredoxin1 (PRDX1), a redox signaling protein overexpressed in CRC cells, through a nuclear factor-erythroid-2-related factor 2 (Nrf2)-dependent pathway, thus amplifying the mitogen-activated protein kinases (MAPKs)/p53-mediated apoptotic signaling by increasing the p-p38, p-JNK levels, as well as the cleaved caspases -3, -8 and -9. In vivo experiments further confirmed the anti-proliferative impact of PRDX1 following furanodienone treatment. In summary, the study demonstrated that furanodienone-induced apoptosis in CRC cells is initiated by mitochondrial ROS derived from NOX4, which targeted the PRDX1 and activated the downstream MAPKs/p53-mediated caspase-dependent signaling pathway. Our findings may provide novel insights into the development of adjuvant drugs for CRC treatment and therapeutic applications.

Oxidative stress and regulation of adipogenic differentiation capacity by sirtuins in adipose stem cells derived from female patients of advancing age

Patient age is critical for mesenchymal stem cell quality and differentiation capacity. We demonstrate that proliferation and adipogenic capacity of subcutaneous adipose stem cells (ASCs) from female patients declined with advanced age, associated with reduction in cell nucleus size, increase in nuclear lamina protein lamin B1/B2, and lamin A, upregulation of senescence marker p16INK4a and senescence-associated β-galactosidase activity. Adipogenic induction resulted in differentiation of adipocytes and upregulation of adipogenic genes CCAAT enhancer binding protein alpha, fatty acid binding protein 4, lipoprotein lipase, and peroxisome proliferator-activated receptor-γ, which was not affected by the Sirt-1 activator YK-3-237 or the Sirt-1 inhibitor EX-527. Protein expression of the stem cell markers Oct4 and Sox2 was not significantly downregulated with advanced patient age. Mitochondrial reactive oxygen species were increased in ASCs from old-aged patients, whereas protein expression of NADPH oxidases NOX1 and NOX4 was downregulated, and dual oxidase isoforms remained unchanged. Generation of nitric oxide and iNOS expression was downregulated. Protein expression of Sirt-1 and Sirt-3 decreased with patient age, whereas Sirt-2 and Sirt-5 remained unchanged. Induction of adipogenesis stimulated protein expression of Sirt-1 and Sirt-3, which was not affected upon pre-incubation with the Sirt-1-activator YK-3-237 or the Sirt-1-inhibitor EX-527. The Sirt-1 inhibitor Sirtinol downregulated adiponectin protein expression and the number of adipocytes, whereas YK-3-237 exerted stimulatory effects. In summary, our data demonstrate increased oxidative stress in ASCs of aging patients, and decline of adipogenic capacity due to Sirt-1- mediated adiponectin downregulation in elderly patients.

NOX4-reactive oxygen species axis: critical regulators of bone health and metabolism

Bone marrow stromal cells (BMSCs) play a significant role in bone metabolism as they can differentiate into osteoblasts, bone marrow adipocytes (BMAds), and chondrocytes. BMSCs chronically exposed to nutrient overload undergo adipogenic programming, resulting in bone marrow adipose tissue (BMAT) formation. BMAT is a fat depot transcriptionally, metabolically, and morphologically distinct from peripheral adipose depots. Reactive oxygen species (ROS) are elevated in obesity and serve as important signals directing BMSC fate. ROS produced by the NADPH oxidase (NOX) family of enzymes, such as NOX4, may be responsible for driving BMSC adipogenesis at the expense of osteogenic differentiation. The dual nature of ROS as both cellular signaling mediators and contributors to oxidative stress complicates their effects on bone metabolism. This review discusses the complex interplay between ROS and BMSC differentiation in the context of metabolic bone diseases.Special attention is paid to the role of NOX4-ROS in regulating cellular processes within the bone marrow microenvironment and potential target in metabolic bone diseases.

Targeting Metabolic-Redox Nexus to Regulate Drug Resistance: From Mechanism to Tumor Therapy

Drug resistance is currently one of the biggest challenges in cancer treatment. With the deepening understanding of drug resistance, various mechanisms have been revealed, including metabolic reprogramming and alterations of redox balance. Notably, metabolic reprogramming mediates the survival of tumor cells in harsh environments, thereby promoting the development of drug resistance. In addition, the changes during metabolic pattern shift trigger reactive oxygen species (ROS) production, which in turn regulates cellular metabolism, DNA repair, cell death, and drug metabolism in direct or indirect ways to influence the sensitivity of tumors to therapies. Therefore, the intersection of metabolism and ROS profoundly affects tumor drug resistance, and clarifying the entangled mechanisms may be beneficial for developing drugs and treatment methods to thwart drug resistance. In this review, we will summarize the regulatory mechanism of redox and metabolism on tumor drug resistance and highlight recent therapeutic strategies targeting metabolic-redox circuits, including dietary interventions, novel chemosynthetic drugs, drug combination regimens, and novel drug delivery systems.

Binge alcohol induces NRF2-related antioxidant response in the skeletal muscle of female mice

BACKGROUND

Chronic alcohol enhances oxidative stress, but the temporal response of antioxidant genes in skeletal muscle following a binge drinking episode remains unknown.

METHODS

Experiment 1: C57BL/6Hsd female mice received an IP injection of saline (CON; n = 39) or ethanol (ETOH; n = 39) (5 g/kg). Gastrocnemius muscles were collected from baseline (untreated; n = 3), CON (n = 3), and ETOH (n = 3) mice every 4 h for 48 h. Experiment 2: Gastrocnemius muscles were collected from control-fed (CON-FED; n = 17), control-fasted (CON-FAST; n = 18), or alcohol-fed (ETOH-FED; n = 18) mice every 4hrs for 20hrs after saline or ethanol (5 g/kg).

RESULTS

EtOH enhanced Superoxide dismutase 1 (Sod1) and NADPH Oxidase 4 (Nox4) from 24 to 48hr after the binge, while Sod2 and Nox2 were suppressed. Nuclear factor erythroid-derived 2-like 2 (Nrf2) and Kelch-like ECH-associated protein 1 (Keap1) increased 12hrs after intoxication. Cytochrome P450 oxidoreductase (Por), Heme oxygenase 1 (Ho1), Peroxiredoxin 6 (Prdx6), Glutamate-cysteine ligase catalytic subunit (Gclc), Glutamate-cysteine ligase modifier subunit (Gclm), and Glutathione-disulfide reductase (Gsr) were increased by ETOH starting 12-16hrs post-binge. Fasting had similar effects on Nrf2 compared to alcohol, but downstream targets of NRF2, including Por, Ho1, Gclc, and Gclm, were differentially altered with fasting and EtOH.

CONCLUSION

These data suggest that acute alcohol intoxication induced markers of oxidative stress and antioxidant signaling through the NRF2 pathway and that there were effects of alcohol independent of a possible decrease in food intake caused by binge intoxication.

Redox signaling and skeletal muscle adaptation during aerobic exercise

Redox regulation is a fundamental physiological phenomenon related to oxygen-dependent metabolism, and skeletal muscle is mainly regarded as a primary site for oxidative phosphorylation. Several studies have revealed the importance of reactive oxygen and nitrogen species (RONS) in the signaling process relating to muscle adaptation during exercise. To date, improving knowledge of redox signaling in modulating exercise adaptation has been the subject of comprehensive work and scientific inquiry. The primary aim of this review is to elucidate the molecular and biochemical pathways aligned to RONS as activators of skeletal muscle adaptation and to further identify the interconnecting mechanisms controlling redox balance. We also discuss the RONS-mediated pathways during the muscle adaptive process, including mitochondrial biogenesis, muscle remodeling, vascular angiogenesis, neuron regeneration, and the role of exogenous antioxidants.

Self-Assembly of Peptides as an Alluring Approach toward Cancer Treatment and Imaging

Cancer is a severe threat to humans, as it is the second leading cause of death after cardiovascular diseases and still poses the biggest challenge in the world of medicine. Due to its higher mortality rates and resistance, it requires a more focused and productive approach to provide the solution for it. Many therapies promising to deliver favorable results, such as chemotherapy and radiotherapy, have come up with more negatives than positives. Therefore, a new class of medicinal solutions and a more targeted approach is of the essence. This review highlights the alluring properties, configurations, and self-assembly of peptide molecules which benefit the traditional approach toward cancer therapy while sparing the healthy cells in the process. As targeted drug delivery systems, self-assembled peptides offer a wide spectrum of conjugation, biocompatibility, degradability-controlled responsiveness, and biomedical applications, including cancer treatment and cancer imaging.

Use of Optical Redox Imaging to Quantify Alveolar Macrophage Redox State in Infants: Proof of Concept Experiments in a Murine Model and Human Tracheal Aspirates Samples

Emerging data indicate that lung macrophages (LM) may provide a novel biomarker to classify disease endotypes in bronchopulmonary dysplasia (BPD), a form of infant chronic lung disease, and that augmentation of the LM phenotype may be a potential therapeutic target. To contribute to this area of research, we first used Optical Redox Imaging (ORI) to characterize the responses to H2O2-induced oxidative stress and caffeine treatment in an in vitro model of mouse alveolar macrophages (AM). H2O2 caused a dose-dependent decrease in NADH and an increase in FAD-containing flavoproteins (Fp) and the redox ratio Fp/(NADH + Fp). Caffeine treatment did not affect Fp but significantly decreased NADH with doses of ≥50 µM, and 1000 µM caffeine treatment significantly increased the redox ratio and decreased the baseline level of mitochondrial ROS (reactive oxygen species). However, regardless of whether AM were pretreated with caffeine or not, the mitochondrial ROS levels increased to similar levels after H2O2 challenge. We then investigated the feasibility of utilizing ORI to examine macrophage redox status in tracheal aspirate (TA) samples obtained from premature infants receiving invasive ventilation. We observed significant heterogeneity in NADH, Fp, Fp/(NADH + Fp), and mitochondrial ROS of the TA macrophages. We found a possible positive correlation between gestational age and NADH and a negative correlation between mean airway pressure and NADH that provides hypotheses for future testing. Our study demonstrates that ORI is a feasible technique to characterize macrophage redox state in infant TA samples and supports further use of this method to investigate lung macrophage-mediated disease endotypes in BPD.

Targeted inhibition of the PI3K/AKT/mTOR pathway by (+)-anthrabenzoxocinone induces cell cycle arrest, apoptosis, and autophagy in non-small cell lung cancer

Non-small cell lung cancer (NSCLC), characterized by low survival rates and a high recurrence rate, is a major cause of cancer-related mortality. Aberrant activation of the PI3K/AKT/mTOR signaling pathway is a common driver of NSCLC. Within this study, the inhibitory activity of (+)-anthrabenzoxocinone ((+)-ABX), an oxygenated anthrabenzoxocinone compound derived from Streptomyces, against NSCLC is demonstrated for the first time both in vitro and in vivo. Mechanistically, it is confirmed that the PI3K/AKT/mTOR signaling pathway is targeted and suppressed by (+)-ABX, resulting in the induction of S and G2/M phase arrest, apoptosis, and autophagy in NSCLC cells. Additionally, the augmentation of intracellular ROS levels by (+)-ABX is revealed, further contributing to the inhibition of the signaling pathway and exerting inhibitory effects on tumor growth. The findings presented in this study suggest that (+)-ABX possesses the potential to serve as a lead compound for the treatment of NSCLC.

Specific NOX4 Inhibition Preserves Mitochondrial Function and Dampens Kidney Dysfunction Following Ischemia-Reperfusion-Induced Kidney Injury

Background: Acute kidney injury (AKI) is a sudden episode of kidney failure which is frequently observed at intensive care units and related to high morbidity/mortality. Although AKI can have many different causes, ischemia-reperfusion (IR) injury is the main cause of AKI. Mechanistically, NADPH oxidases (NOXs) are involved in the pathophysiology contributing to oxidative stress following IR. Previous reports have indicated that knockout of NOX4 may offer protection in cardiac and brain IR, but there is currently less knowledge about how this could be exploited therapeutically and whether this could have significant protection in IR-induced AKI. Aim: To investigate the hypothesis that a novel and specific NOX4 inhibitor (GLX7013114) may have therapeutic potential on kidney and mitochondrial function in a mouse model of IR-induced AKI. Methods: Kidneys of male C57BL/6J mice were clamped for 20 min, and the NOX4 inhibitor (GLX7013114) was administered via osmotic minipump during reperfusion. Following 3 days of reperfusion, kidney function (i.e., glomerular filtration rate, GFR) was calculated from FITC-inulin clearance and mitochondrial function was assessed by high-resolution respirometry. Renal histopathological evaluations (i.e., hematoxylin-eosin) and TUNEL staining were performed for apoptotic evaluation. Results: NOX4 inhibition during reperfusion significantly improved kidney function, as evidenced by a better-maintained GFR (p < 0.05) and lower levels of blood urea nitrogen (p < 0.05) compared to untreated IR animals. Moreover, IR caused significant tubular injuries that were attenuated by simultaneous NOX4 inhibition (p < 0.01). In addition, the level of renal apoptosis was significantly reduced in IR animals with NOX4 inhibition (p < 0.05). These favorable effects of the NOX4 inhibitor were accompanied by enhanced Nrf2 Ser40 phosphorylation and conserved mitochondrial function, as evidenced by the better-preserved activity of all mitochondrial complexes. Conclusion: Specific NOX4 inhibition, at the time of reperfusion, significantly preserves mitochondrial and kidney function. These novel findings may have clinical implications for future treatments aimed at preventing AKI and related adverse events, especially in high-risk hospitalized patients.

Roles of reactive oxygen species in inflammation and cancer

Reactive oxygen species (ROS) constitute a spectrum of oxygenic metabolites crucial in modulating pathological organism functions. Disruptions in ROS equilibrium span various diseases, and current insights suggest a dual role for ROS in tumorigenesis and the immune response within cancer. This review rigorously examines ROS production and its role in normal cells, elucidating the subsequent regulatory network in inflammation and cancer. Comprehensive synthesis details the documented impacts of ROS on diverse immune cells. Exploring the intricate relationship between ROS and cancer immunity, we highlight its influence on existing immunotherapies, including immune checkpoint blockade, chimeric antigen receptors, and cancer vaccines. Additionally, we underscore the promising prospects of utilizing ROS and targeting ROS modulators as novel immunotherapeutic interventions for cancer. This review discusses the complex interplay between ROS, inflammation, and tumorigenesis, emphasizing the multifaceted functions of ROS in both physiological and pathological conditions. It also underscores the potential implications of ROS in cancer immunotherapy and suggests future research directions, including the development of targeted therapies and precision oncology approaches. In summary, this review emphasizes the significance of understanding ROS-mediated mechanisms for advancing cancer therapy and developing personalized treatments.

NOX4 alleviates breast cancer cell aggressiveness by co-ordinating mitochondrial turnover through PGC1α/Drp1 axis

Triple Negative Breast Cancer (TNBC) is a highly aggressive form of breast cancer, with few treatment options. This study investigates the complex molecular mechanism by which NADPH oxidase 4 (NOX4), a major ROS producer in mitochondria, affects the aggressiveness of luminal and triple-negative breast cancer cells (TNBCs). We found that NOX4 expression was differentially regulated in luminal and TNBC cells, with a positive correlation to their epithelial characteristics. Time dependent analysis revealed that TNBCs exhibits higher steady-state ROS levels than luminal cells, but NOX4 silencing increased ROS levels in luminal breast cancer cells and enhanced their ability to migrate and invade. In contrast, NOX4 over expression in TNBCs had the opposite effect. The mouse tail-vein experiment showed that the group injected with NOX4 silenced luminal cells had a higher number of lung metastases compared to the control group. Mechanistically, NOX4 enhanced PGC1α dependent mitochondrial biogenesis and attenuated Drp1-mediated mitochondrial fission in luminal breast cancer cells, leading to an increased mitochondrial mass and elongated mitochondrial morphology. Interestingly, NOX4 silencing increased mitochondrial ROS (mtROS) levels without affecting mitochondrial (Δψm) and cellular integrity. Inhibition of Drp1-dependent fission with Mdivi1 reversed the effect of NOX4-dependent mitochondrial biogenesis, dynamics, and migration of breast cancer cells. Our findings suggest that NOX4 expression diminishes from luminal to a triple negative state, accompanied by elevated ROS levels, which may modulate mitochondrial turnover to attain an aggressive phenotype. The study provides potential insights for targeted therapies for TNBCs.

Role of Oxygen and Its Radicals in Peripheral Nerve Regeneration: From Hypoxia to Physoxia to Hyperoxia

Oxygen is compulsory for mitochondrial function and energy supply, but it has numerous more nuanced roles. The different roles of oxygen in peripheral nerve regeneration range from energy supply, inflammation, phagocytosis, and oxidative cell destruction in the context of reperfusion injury to crucial redox signaling cascades that are necessary for effective axonal outgrowth. A fine balance between reactive oxygen species production and antioxidant activity draws the line between physiological and pathological nerve regeneration. There is compelling evidence that redox signaling mediated by the Nox family of nicotinamide adenine dinucleotide phosphate (NADPH) oxidases plays an important role in peripheral nerve regeneration. Further research is needed to better characterize the role of Nox in physiological and pathological circumstances, but the available data suggest that the modulation of Nox activity fosters great therapeutic potential. One of the promising approaches to enhance nerve regeneration by modulating the redox environment is hyperbaric oxygen therapy. In this review, we highlight the influence of various oxygenation states, i.e., hypoxia, physoxia, and hyperoxia, on peripheral nerve repair and regeneration. We summarize the currently available data and knowledge on the effectiveness of using hyperbaric oxygen therapy to treat nerve injuries and discuss future directions.

Mitochondrion: Main organelle in orchestrating cancer escape from chemotherapy

BACKGROUND

Chemoresistance is a challenging barrier to cancer therapy, and in this context, the role of mitochondria is significant. We put emphasis on key biological characteristics of mitochondria, contributing to tumor escape from various therapies, to find the "Achilles' Heel" of cancer cells for future drug design.

RECENT FINDINGS

The mitochondrion is a dynamic organelle, and its existence is important for tumor growth. Its metabolites also cooperate with cell signaling in tumor proliferation and drug resistance.

CONCLUSION

Biological characteristics of this organelle, such as redox balance, DNA depletion, and metabolic reprogramming, provide flexibility to cancer cells to cope with therapy-induced stress.

Mitochondrial Dysfunction, Oxidative Stress, and Inter-Organ Miscommunications in T2D Progression

Type 2 diabetes (T2D) is a heterogenous disease, and conventionally, peripheral insulin resistance (IR) was thought to precede islet β-cell dysfunction, promoting progression from prediabetes to T2D. New evidence suggests that T2D-lean individuals experience early β-cell dysfunction without significant IR. Regardless of the primary event (i.e., IR vs. β-cell dysfunction) that contributes to dysglycemia, significant early-onset oxidative damage and mitochondrial dysfunction in multiple metabolic tissues may be a driver of T2D onset and progression. Oxidative stress, defined as the generation of reactive oxygen species (ROS), is mediated by hyperglycemia alone or in combination with lipids. Physiological oxidative stress promotes inter-tissue communication, while pathological oxidative stress promotes inter-tissue mis-communication, and new evidence suggests that this is mediated via extracellular vesicles (EVs), including mitochondria containing EVs. Under metabolic-related stress conditions, EV-mediated cross-talk between β-cells and skeletal muscle likely trigger mitochondrial anomalies leading to prediabetes and T2D. This article reviews the underlying molecular mechanisms in ROS-related pathogenesis of prediabetes, including mitophagy and mitochondrial dynamics due to oxidative stress. Further, this review will describe the potential of various therapeutic avenues for attenuating oxidative damage, reversing prediabetes and preventing progression to T2D.

The Association between NADPH Oxidase 2 (NOX2) and Drug Resistance in Cancer

NADPH oxidase, as a major source of intracellular reactive oxygen species (ROS), assumes an important role in the immune response and oxidative stress response of the body. NADPH oxidase 2 (NOX2) is the first and most representative member of the NADPH oxidase family, and its effects on the development of tumor cells are gaining more and more attention. Our previous study suggested that NCF4 polymorphism in p40phox, a key subunit of NOX2, affected the outcome of diffuse large B-cell lymphoma patients treated with rituximab. It hypothesized that NOX2-mediated ROS could enhance the cytotoxic effects of some anti-tumor drugs in favor of patients with tumors. Several reviews have summarized the role of NOX2 and its congeners-mediated ROS in anti-tumor therapy, but few studies focused on the relationship between the expression of NOX2 and anti-tumor drug resistance. In this article, we systematically introduced the NOX family, represented by NOX2, and a classification of the latest inhibitors and agonists of NOX2. It will help researchers to have a more rational and objective understanding of the dual role of NOX2 in tumor drug resistance and is expected to provide new ideas for oncology treatment and overcoming drug resistance in cancer.

Colon Cancer Cells Evade Drug Action by Enhancing Drug Metabolism

Colorectal cancer (CRC) is the second most deadly cancer worldwide. One key reason is the failure of therapies that target RAS proteins, which represent approximately 40% of CRC cases. Despite the recent discovery of multiple alternative signalling pathways that contribute to resistance, durable therapies remain an unmet need. Here, we use liquid chromatography/mass spectrometry (LC/MS) analyses on Drosophila CRC tumour models to identify multiple metabolites in the glucuronidation pathway-a toxin clearance pathway-as upregulated in trametinib-resistant RAS/APC/P53 ("RAP") tumours compared to trametinib-sensitive RASG12V tumours. Elevating glucuronidation was sufficient to direct trametinib resistance in RASG12V animals while, conversely, inhibiting different steps along the glucuronidation pathway strongly reversed RAP resistance to trametinib. For example, blocking an initial HDAC1-mediated deacetylation step with the FDA-approved drug vorinostat strongly suppressed trametinib resistance in Drosophila RAP tumours. We provide functional evidence that pairing oncogenic RAS with hyperactive WNT activity strongly elevates PI3K/AKT/GLUT signalling, which in turn directs elevated glucose and subsequent glucuronidation. Finally, we show that this mechanism of trametinib resistance is conserved in an KRAS/APC/TP53 mouse CRC tumour organoid model. Our observations demonstrate a key mechanism by which oncogenic RAS/WNT activity promotes increased drug clearance in CRC. The majority of targeted therapies are glucuronidated, and our results provide a specific path towards abrogating this resistance in clinical trials.

Role of Mitochondria in Intestinal Epithelial Barrier Dysfunction in Inflammatory Bowel Disease

Abstract

Inflammatory bowel disease (IBD) is widespread in industrial countries with every 20th citizen being affected. Dysregulation of the epithelial barrier function is considered to play a key role in IBD. Permeability of the intestinal epithelium depends mostly on its self-renewal potential and the condition of intercellular junctions. Mitochondria are involved in regulating various intracellular processes in addition to their energy function. Recent data implicate mitochondria in intestinal epithelial barrier regulation and IBD. Mitochondrial dysfunction is possibly one of the factors that underlie the structural abnormalities of tight junctions and the cytoskeleton in intestinal epithelial cells and decrease the self-renewal capacity of the epithelium. The barrier function of the intestinal epithelium is consequently distorted, and IBD develops. The mechanisms of these processes are still unclear and require further research.

Endothelial cells differentially sense laminar and disturbed flows by altering the lipid order of their plasma and mitochondrial membranes

Endothelial cells (ECs) experience two different blood flow patterns: laminar and disturbed flow. Their responses to laminar flow contribute to vascular homeostasis, whereas their responses to disturbed flow result in EC dysfunction and vascular diseases. However, it remains unclear how ECs differentially sense laminar and disturbed flow and trigger signaling that elicits different responses. Here, we showed that ECs differentially sense laminar and disturbed flows by altering the lipid order of their plasma and mitochondrial membranes in opposite directions. This results in distinct changes in mitochondrial function, namely, increased adenosine triphosphate (ATP) production for laminar flow and increased hydrogen peroxide (H2O2) release for disturbed flow, leading to ATP- and H2O2-mediated signaling, respectively. When cultured human aortic ECs were subjected to laminar or disturbed flow in flow-loading devices, the lipid order of their plasma membranes immediately decreased in response to laminar flow and increased in response to disturbed flow. Laminar flow also decreased the lipid order of mitochondrial membranes and increased mitochondrial ATP production. In contrast, disturbed flow increased the lipid order of mitochondrial membranes and increased the release of H2O2 from the mitochondria. The addition of cholesterol to the cells increased the lipid order of both membranes and abrogated laminar flow-induced ATP production, while treatment of the cells with a cholesterol-depleting reagent, methyl-β cyclodextrin, decreased the lipid order of both membranes and abolished disturbed flow-induced H2O2 release, indicating that changes in the membrane lipid order and/or cholesterol content are closely linked to flow-induced changes in mitochondrial functions.NEW & NOTEWORTHY How vascular endothelial cells (ECs) differentially sense laminar and disturbed flows and trigger intracellular signaling remains unclear. Here, we show that EC plasma membranes act as mechanosensors to discriminate between laminar and disturbed flows by undergoing opposite changes in their lipid order. Similar lipid order changes occur simultaneously in the mitochondrial membranes, which are linked to changes in mitochondrial function, that is, increased ATP production for laminar flow and increased H2O2 release for disturbed flow.

Potential therapies targeting nuclear metabolic regulation in cancer

The interplay between genetic alterations and metabolic dysregulation is increasingly recognized as a pivotal axis in cancer pathogenesis. Both elements are mutually reinforcing, thereby expediting the ontogeny and progression of malignant neoplasms. Intriguingly, recent findings have highlighted the translocation of metabolites and metabolic enzymes from the cytoplasm into the nuclear compartment, where they appear to be intimately associated with tumor cell proliferation. Despite these advancements, significant gaps persist in our understanding of their specific roles within the nuclear milieu, their modulatory effects on gene transcription and cellular proliferation, and the intricacies of their coordination with the genomic landscape. In this comprehensive review, we endeavor to elucidate the regulatory landscape of metabolic signaling within the nuclear domain, namely nuclear metabolic signaling involving metabolites and metabolic enzymes. We explore the roles and molecular mechanisms through which metabolic flux and enzymatic activity impact critical nuclear processes, including epigenetic modulation, DNA damage repair, and gene expression regulation. In conclusion, we underscore the paramount significance of nuclear metabolic signaling in cancer biology and enumerate potential therapeutic targets, associated pharmacological interventions, and implications for clinical applications. Importantly, these emergent findings not only augment our conceptual understanding of tumoral metabolism but also herald the potential for innovative therapeutic paradigms targeting the metabolism-genome transcriptional axis.

NOX2 control over energy metabolism plays a role in acute myeloid leukaemia prognosis and survival

Acute myeloid leukaemia (AML) is a highly heterogeneous disease, however the therapeutic approaches have hardly changed in the last decades. Metabolism rewiring and the enhanced production of reactive oxygen species (ROS) are hallmarks of cancer. A deeper understanding of these features could be instrumental for the development of specific AML-subtypes treatments. NADPH oxidases (NOX), the only cellular system specialised in ROS production, are also involved in leukemic metabolism control. NOX2 shows a variable expression in AML patients, so patients can be classified based on such difference. Here we have analysed whether NOX2 levels are important for AML metabolism control. The lack of NOX2 in AML cells slowdowns basal glycolysis and oxidative phosphorylation (OXPHOS), along with the accumulation of metabolites that feed such routes, and a sharp decrease of glutathione. In addition, we found changes in the expression of 725 genes. Among them, we have discovered a panel of 30 differentially expressed metabolic genes, whose relevance was validated in patients. This panel can segregate AML patients according to CYBB expression, and it can predict patient prognosis and survival. In summary, our data strongly support the relevance of NOX2 for AML metabolism, and highlights the potential of our discoveries in AML prognosis.

Effects of SIDT2 on the miR-25/NOX4/HuR axis and SIRT3 mRNA stability lead to ROS-mediated TNF-α expression in hydroquinone-treated leukemia cells

Our previous studies indicated that the benzene metabolite hydroquinone (HQ) evokes the ROS/p38 MAPK/protein phosphatase 2A/tristetraprolin axis, leading to increased TNF-α expression in human acute myeloid leukemia cell lines U937 and HL-60. In this study, we aimed to identify the upstream pathway involved in ROS-mediated TNF-α expression. HQ treatment increased SIDT2 expression, which subsequently decreased miR-25 and SIRT3 expression in U937 cells. Notably, miR-25 downregulation promoted SIDT2 expression in HQ-treated U937 cells. SIDT2 induced lysosomal degradation of SIRT3 mRNA, but inhibited miR-25 expression through a lysosome-independent pathway. MiR-25 inhibition reduced NOX4 mRNA turnover, resulting in increased NOX4 protein levels. NOX4 induces mitochondrial ROS production and HuR downregulation. Restoration of HuR expression increased SIRT3 expression, suggesting that NOX4-mediated HuR downregulation promotes SIDT2-mediated degradation of SIRT3 mRNA. Inhibition of NOX4 or SIRT3 overexpression abolished HQ-induced ROS production, thereby abolishing TNF-α upregulation. Overall, these results indicate that SIDT2 regulates the miR-25/NOX4/HuR axis and SIRT3 mRNA destabilization, leading to ROS-mediated TNF-α upregulation in HQ-treated U937 cells. HQ-induced increase in TNF-α expression in HL-60 cells was also mediated through a similar pathway.

NADPH Oxidases: From Molecular Mechanisms to Current Inhibitors

NADPH oxidases (NOXs) form a family of electron-transporting membrane enzymes whose main function is reactive oxygen species (ROS) generation. Strong evidence suggests that ROS produced by NOX enzymes are major contributors to oxidative damage under pathologic conditions. Therefore, blocking the undesirable actions of these enzymes is a therapeutic strategy for treating various pathological disorders, such as cardiovascular diseases, inflammation, and cancer. To date, identification of selective NOX inhibitors is quite challenging, precluding a pharmacologic demonstration of NOX as therapeutic targets in vivo. The aim of this Perspective is to furnish an updated outlook about the small-molecule NOX inhibitors described over the last two decades. Structures, activities, and in vitro/in vivo specificity are discussed, as well as the main biological assays used.

A Cyclodiaryliodonium NOX Inhibitor for the Treatment of Pancreatic Cancer via Enzyme-Activatable Targeted Delivery by Sulfated Glycosaminoglycan Derivatives

Pancreatic cancer renders a principal cause of cancer mortalities with a dismal prognosis, lacking sufficiently safe and effective therapeutics. Here, diversified cyclodiaryliodonium (CDAI) NADPH oxidase (NOX) inhibitors are rationally designed with tens of nanomolar optimal growth inhibition, and CD44-targeted delivery is implemented using synthesized sulfated glycosaminoglycan derivatives. The self-assembled nanoparticle-drug conjugate (NDC) enables hyaluronidase-activatable controlled release and facilitates cellular trafficking. NOX inhibition reprograms the metabolic phenotype by simultaneously impairing mitochondrial respiration and glycolysis. Moreover, the NDC selectively diminishes non-mitochondrial reactive oxygen species (ROS) but significantly elevates cytotoxic ROS through mitochondrial membrane depolarization. Transcriptomic profiling reveals perturbed p53, NF-κB, and GnRH signaling pathways interconnected with NOX inhibition. After being validated in patient-derived pancreatic cancer cells, the anticancer efficacy is further verified in xenograft mice bearing heterotopic and orthotopic pancreatic tumors, with extended survival and ameliorated systemic toxicity. It is envisaged that the translation of cyclodiaryliodonium inhibitors with an optimized molecular design can be expedited by enzyme-activatable targeted delivery with improved pharmacokinetic profiles and preserved efficacy.

NOX4 is a potential therapeutic target in septic acute kidney injury by inhibiting mitochondrial dysfunction and inflammation

Rationale: Sepsis is a severe clinical syndrome featured through organ dysfunction due to infection, while the accompanying acute kidney injury (AKI) is linked to significant incidence of morbidity as well as mortality. Recently, emerging evidence has revealed that nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 4 (NOX4) is implicated in various renal diseases, while its role and modulation in septic acute kidney injury (S-AKI) remains largely unknown. Methods: In vivo, S-AKI in wild-type and renal tubular epithelial cell (RTEC)-specific NOX4 knockout mice was induced by lipopolysaccharides (LPS) injection or cecal ligation and puncture (CLP). In vitro, TCMK-1 (mouse kidney tubular epithelium cell line) cells were treated with LPS. Serum and supernatant biochemical, mitochondrial dysfunctional, inflammatory and apoptotic parameters were measured and compared across groups. The activation of reactive oxygen species (ROS) and NF-κB signaling was also assessed. Results: NOX4 was predominantly upregulated in RTECs of S-AKI mouse model induced by LPS/CLP and cultured TCMK-1 cells exposed to LPS. RTEC-specific deletion of NOX4 or pharmacological inhibition of NOX4 by GKT137831 both alleviated LPS/CLP-injured renal function and pathology in mice. Furthermore, NOX4 inhibition alleviated mitochondrial dysfunction supported by ultrastructural damage, reduction of ATP production and mitochondrial dynamics imbalance, together with inflammation and apoptosis in kidney injured by LPS/CLP and TCMK-1 cells injured by LPS, while NOX4 overexpression aggravated the above-mentioned indices in TCMK-1 cells with LPS stimulation. Mechanism-wise, the raised NOX4 in RTECs may induce ROS and NF-κB signaling activation in S-AKI. Conclusions: Collectively, genetic or pharmacological inhibition of NOX4 protects from S-AKI by reducing generation of ROS and activation of NF-κB signal, which suppress mitochondrial dysfunction, inflammation together with apoptosis. NOX4 may act as a novel target for the S-AKI therapy.

Abscisic acid increases hydrogen peroxide in mitochondria to facilitate stomatal closure

Abscisic acid (ABA) drives stomatal closure to minimize water loss due to transpiration in response to drought. We examined the subcellular location of ABA-increased accumulation of reactive oxygen species (ROS) in guard cells, which drive stomatal closure, in Arabidopsis (Arabidopsis thaliana). ABA-dependent increases in fluorescence of the generic ROS sensor, dichlorofluorescein (DCF), were observed in mitochondria, chloroplasts, cytosol, and nuclei. The ABA response in all these locations was lost in an ABA-insensitive quintuple receptor mutant. The ABA-increased fluorescence in mitochondria of both DCF- and an H2O2-selective probe, Peroxy Orange 1, colocalized with Mitotracker Red. ABA treatment of guard cells transformed with the genetically encoded H2O2 reporter targeted to the cytoplasm (roGFP2-Orp1), or mitochondria (mt-roGFP2-Orp1), revealed H2O2 increases. Consistent with mitochondrial ROS changes functioning in stomatal closure, we found that guard cells of a mutant with mitochondrial defects, ABA overly sensitive 6 (abo6), have elevated ABA-induced ROS in mitochondria and enhanced stomatal closure. These effects were phenocopied with rotenone, which increased mitochondrial ROS. In contrast, the mitochondrially targeted antioxidant, MitoQ, dampened ABA effects on mitochondrial ROS accumulation and stomatal closure in Col-0 and reversed the guard cell closure phenotype of the abo6 mutant. ABA-induced ROS accumulation in guard cell mitochondria was lost in mutants in genes encoding respiratory burst oxidase homolog (RBOH) enzymes and reduced by treatment with the RBOH inhibitor, VAS2870, consistent with RBOH machinery acting in ABA-increased ROS in guard cell mitochondria. These results demonstrate that ABA elevates H2O2 accumulation in guard cell mitochondria to promote stomatal closure.

The selective NOX4 inhibitor GLX7013159 decreases blood glucose concentrations and human beta-cell apoptotic rates in diabetic NMRI nu/nu mice transplanted with human islets

NADPH oxidase 4 (NOX4) inhibition has been reported to mitigate diabetes-induced beta-cell dysfunction and improve survival in vitro, as well as counteract high-fat diet-induced glucose intolerance in mice. We investigated the antidiabetic effects of the selective NOX4 inhibitor GLX7013159 in vivo in athymic diabetic mice transplanted with human islets over a period of 4 weeks. The GLX7013159-treated mice achieved lower blood glucose and water consumption throughout the treatment period. Furthermore, GLX7013159 treatment resulted in improved insulin and c-peptide levels, better insulin secretion capacity, as well as in greatly reduced apoptotic rates of the insulin-positive human cells, measured as colocalization of insulin and cleaved caspase-3. We conclude that the antidiabetic effects of NOX4 inhibition by GLX7013159 are observed also during a prolonged study period in vivo and are likely to be due to an improved survival and function of the human beta-cells.

DDRGK1 Enhances Osteosarcoma Chemoresistance via Inhibiting KEAP1-Mediated NRF2 Ubiquitination

Chemoresistance is the main obstacle in osteosarcoma (OS) treatment; however, the underlying mechanism remains unclear. In this study, it is discovered that DDRGK domain-containing protein 1 (DDRGK1) plays a fundamental role in chemoresistance induced in OS. Bioinformatic and tissue analyses indicate that higher expression of DDRGK1 correlates with advanced tumor stage and poor clinical prognosis of OS. Quantitative proteomic analyses suggest that DDRGK1 plays a critical role in mitochondrial oxidative phosphorylation. DDRGK1 knockout trigger the accumulation of reactive oxygen species (ROS) and attenuate the stability of nuclear factor erythroid-2-related factor 2 (NRF2), a major antioxidant response element. Furthermore, DDRGK1 inhibits ubiquitin-proteasome-mediated degradation of NRF2 via competitive binding to the Kelch-like ECH-associated protein 1 (KEAP1) protein, which recruits NRF2 to CULLIN(CUL3). DDRGK1 knockout attenuates NRF2 stability, contributing to ROS accumulation, which promotes apoptosis and enhanced chemosensitivity to doxorubicin (DOX) and etoposide in cancer cells. Indeed, DDRGK1 knockout significantly enhances osteosarcoma chemosensitivity to DOX in vivo. The combination of DDRGK1 knockdown and DOX treatment provides a promising new avenue for the effective treatment of OS.

NOX4-derived ROS are neuroprotective by balancing intracellular calcium stores

Hyperexcitability is associated with neuronal dysfunction, cellular death, and consequently neurodegeneration. Redox disbalance can contribute to hyperexcitation and increased reactive oxygen species (ROS) levels are observed in various neurological diseases. NOX4 is an NADPH oxidase known to produce ROS and might have a regulating function during oxidative stress. We, therefore, aimed to determine the role of NOX4 on neuronal firing, hyperexcitability, and hyperexcitability-induced changes in neural network function. Using a multidimensional approach of an in vivo model of hyperexcitability, proteomic analysis, and cellular function analysis of ROS, mitochondrial integrity, and calcium levels, we demonstrate that NOX4 is neuroprotective by regulating ROS and calcium homeostasis and thereby preventing hyperexcitability and consequently neuronal death. These results implicate NOX4 as a potential redox regulator that is beneficial in hyperexcitability and thereby might have an important role in neurodegeneration.

Mitochondrial ROS driven by NOX4 upregulation promotes hepatocellular carcinoma cell survival after incomplete radiofrequency ablation by inducing of mitophagy via Nrf2/PINK1

BACKGROUND

The recurrence of hepatocellular carcinoma (HCC) after radiofrequency ablation (RFA) remains a major clinical problem. Cells that survive the sublethal heat stress that is induced by incomplete RFA are the main source of HCC relapse. Heat stress has long been reported to increase intracellular reactive oxygen species (ROS) generation. Although ROS can induce apoptosis, a pro-survival effect of ROS has also been demonstrated. However, the role of ROS in HCC cells exposed to sublethal heat stress remains unclear.

METHODS

HepG2 and HuH7 cells were used for this experiment. Insufficient RFA was performed in cells and in a xenograft model. ROS and antioxidant levels were measured. Apoptosis was analyed by Annexin-V/PI staining and flow cytometry. Protein expression was measured using western blotting. Colocalization of lysosomes and mitochondria was analyzed to assess mitophagy. Corresponding activators or inhibitors were applied to verify the function of specific objectives.

RESULTS

Here,we showed that sublethal heat stress induced a ROS burst, which caused acute oxidative stress. This ROS burst was generated by mitochondria, and it was initiated by upregulated NOX4 expression in the mitochondria. N-acetylcysteine (NAC) decreased HCC cell survival under sublethal heat stress conditions in vivo and in vitro. NOX4 triggers the production of mitochondrial ROS (mtROS), and NOX4 inhibitors or siNOX4 also decreased HCC cell survival under sublethal heat stress conditions in vitro. Increased mtROS trigger PINK1-dependent mitophagy to eliminate the mitochondria that are damaged by sublethal heat stress and to protect cells from apoptosis. Nrf2 expression was elevated in response to this ROS burst and mediated the ROS burst-induced increase in PINK1 expression after sublethal heat stress.

CONCLUSION

These data confirmed that the ROS burst that occurs after iRFA exerted a pro-survival effect. NOX4 increased the generation of ROS by mitochondria. This short-term ROS burst induced PINK1-dependent mitophagy to eliminate damaged mitochondria by increasing Nrf2 expression.

Glutamine metabolism targeting liposomes for synergistic chemosensitization and starvation therapy in ovarian cancer

Platinum-based chemotherapy is a first-line therapeutic regimen against ovarian cancer (OC); however, the therapeutic potential is always reduced by glutamine metabolism. Herein, a valid strategy of inhibiting glutamine metabolism was proposed to cause tumor starvation and chemosensitization. Specifically, reactive oxygen species-responsive liposomes were developed to co-deliver cisplatin (CDDP) and bis-2-(5-phenylacetamido-1,3,4-thiadiazol-2-yl) ethyl sulfide (BPTES) [C@B LPs]. The C@B LPs induced effective tumor cell starvation and significantly sensitized OC cells to CDDP by reducing glutathione generation to prevent CDDP detoxification, suppressing ATP production to avoid CDDP efflux, hindering nucleotide synthesis to aggravate DNA damage induced by CDDP, and blocking mammalian target of rapamycin (mTOR) signaling to promote cell apoptosis. More importantly, C@B LPs remarkably inhibited tumor growth in vivo and reduced the side effects. Taken together, this study provided a successful strategy of synergistic chemosensitization and starvation therapy escalating the rate of therapeutic success in OCs. STATEMENT OF SIGNIFICANCE: This work proposed a valid strategy of inhibiting glutamine metabolism to cause tumor starvation and chemosensitization. Specifically, ROS-responsive liposomes were developed to co-deliver cisplatin CDDP and BPTES [C@B LPs]. The C@B LPs induced effective tumor cell starvation and significantly sensitized OC cells to cisplatin by reducing glutathione generation to prevent cisplatin detoxification, suppressing ATP production to avoid cisplatin efflux, hindering nucleotide synthesis to aggravate DNA damage induced by cisplatin, and blocking mTOR signaling to promote cell apoptosis. More importantly, C@B LPs remarkably inhibited tumor growth in vivo and reduced the side effects. Taken together, this study provided a successful strategy of synergistic chemosensitization and starvation therapy escalating the rate of therapeutic success in OCs.

PKM2 allosteric converter: A self-assembly peptide for suppressing renal cell carcinoma and sensitizing chemotherapy

Stronger intrinsic Warburg effect and resistance to chemotherapy are the responses to high mortality of renal cell carcinoma (RCC). Pyruvate kinase M2 (PKM2) plays an important role in this process. Promoting PKM2 conversion from dimer to tetramer is a critical strategy to inhibit Warburg effect and reverse chemotherapy resistance. Herein, a PKM2 allosteric converter (PAC) is constructed based on the "in vivo self-assembly" strategy, which is able to continuously stimulate PKM2 tetramerization. The PAC contains three motifs, a serine site that is protected by enzyme cleavable β-N-acetylglucosamine, a self-assembly peptide and a AIE motif. Once PAC nanoparticles reach tumor site via the EPR effect, the protective and hydrophilic β-N-acetylglucosamine will be removed by over-expressed O-GlcNAcase (OGA), causing self-assembled peptides to transform into nanofibers with large serine (PKM2 tetramer activator) exposure and long-term retention, which promotes PKM2 tetramerization continuously. Our results show that PAC-induced PKM2 tetramerization inhibits aberrant metabolism mediated by Warburg effect in cytoplasm. In this way, tumor proliferation and metastasis behavior could be effectively inhibited. Meanwhile, PAC induced PKM2 tetramerization impedes the nuclear translocation of PKM2 dimer, which restores the sensitivity of cancer cells to first-line anticancer drugs. Collectively, the innovative PAC effectively promotes PKM2 conversion from dimer to tetramer, and it might provide a novel approach for suppressing RCC and enhancing chemotherapy sensitivity.

NOX2 and NOX4 control mitochondrial function in chronic myeloid leukaemia

Cancer cells are characterised by an elevated metabolic plasticity and enhanced production of reactive oxygen species (ROS), two features acknowledged as hallmarks in cancer, with a high translational potential to the therapeutic setting. These aspects, that have been traditionally studied separately, are in fact intimately intermingled. As part of their transforming activity, some oncogenes stimulate rewiring of metabolic processes, whilst simultaneously promoting increased production of intracellular ROS. In this scenario the latest discoveries suggest the relevance of nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOX) to connect ROS production and metabolic control. Here we have analysed the relevance of NOX2 and NOX4 in the regulation of metabolism in chronic myeloid leukaemia (CML), a neoplasia driven by the expression of the breakpoint cluster region-Abelson fusion oncogene (BCR-ABL). Silencing of NOX2 enhances glycolysis and oxidative phosphorylation rates, together with an enhanced production of mitochondrial ROS and a decrease in mitochondrial DNA copy number, which reflects mitochondrial dysfunction. NOX4 expression was upregulated upon NOX2 silencing, and this was required to alter mitochondrial function. Our results support the relevance of NOX2 to regulate metabolism-related signalling pathways downstream of BCR-ABL. Overall we show that NOX2, through the regulation of NOX4 expression, controls metabolism and mitochondrial function in CML cells. This notion was confirmed by transcriptomic analyses, that strongly relate both NOX isoforms with metabolism regulation in CML.

Deletion of Nox4 enhances remyelination following cuprizone-induced demyelination by increasing phagocytic capacity of microglia and macrophages in mice

NOX4 is a major reactive oxygen species-producing enzyme that modulates cell stress responses. We here examined the effect of Nox4 deletion on demyelination-remyelination, the most common pathological change in the brain. We used a model of cuprizone (CPZ)-associated demyelination-remyelination in wild-type and Nox4-deficient (Nox4^-/- ) mice. While the CPZ-induced demyelination in the corpus callosum after 4 weeks of CPZ intoxication was slightly less pronounced in Nox4^-/- mice than that in wild-type mice, remyelination following CPZ withdrawal was significantly enhanced in Nox4^-/- mice with an increased accumulation of IBA1-positive microglia/macrophages in the demyelinating corpus callosum. Consistently, locomotor function, as assessed by the beam walking test, was significantly better during the remyelination phase in Nox4^-/- mice. Nox4 deletion did not affect autonomous growth of primary-culture oligodendrocyte precursor cells. Although Nox4 expression was higher in cultured macrophages than in microglia, Nox4^-/- microglia and macrophages both showed enhanced phagocytic capacity of myelin debris and produced increased amounts of trophic factors upon phagocytosis. The expression of trophic factors was higher, in parallel with the accumulation of IBA1-positive cells, in the corpus callosum in Nox4^-/- mice than that in wild-type mice. Nox4 deletion suppressed phagocytosis-induced increase in mitochondrial membrane potential, enhancing phagocytic capacity of macrophages. Treatment with culture medium of Nox4^-/- macrophages engulfing myelin debris, but not that of Nox4^-/- astrocytes, enhanced cell growth and expression of myelin-associated proteins in cultured oligodendrocyte precursor cells. Collectively, Nox4 deletion promoted remyelination after CPZ-induced demyelination by enhancing microglia/macrophage-mediated clearance of myelin debris and the production of trophic factors leading to oligodendrogenesis.

NOX Dependent ROS Generation and Cell Metabolism

Reactive oxygen species (ROS) represent a group of high reactive molecules with dualistic natures since they can induce cytotoxicity or regulate cellular physiology. Among the ROS, the superoxide anion radical (O2·-) is a key redox signaling molecule prominently generated by the NADPH oxidase (NOX) enzyme family and by the mitochondrial electron transport chain. Notably, altered redox balance and deregulated redox signaling are recognized hallmarks of cancer and are involved in malignant progression and resistance to drugs treatment. Since oxidative stress and metabolism of cancer cells are strictly intertwined, in this review, we focus on the emerging roles of NOX enzymes as important modulators of metabolic reprogramming in cancer. The NOX family includes seven isoforms with different activation mechanisms, widely expressed in several tissues. In particular, we dissect the contribute of NOX1, NOX2, and NOX4 enzymes in the modulation of cellular metabolism and highlight their potential role as a new therapeutic target for tumor metabolism rewiring.

The regulation of cardiac intermediary metabolism by NADPH oxidases

NADPH oxidases (NOXs), enzymes whose primary function is to generate reactive oxygen species, are important regulators of the heart's physiological function and response to pathological insults. The role of NOX-driven redox signalling in pathophysiological myocardial remodelling, including processes such as interstitial fibrosis, contractile dysfunction, cellular hypertrophy, and cell survival, is well recognized. While the NOX2 isoform promotes many detrimental effects, the NOX4 isoform has attracted considerable attention as a driver of adaptive stress responses both during pathology and under physiological states such as exercise. Recent studies have begun to define some of the NOX4-modulated mechanisms that may underlie these adaptive responses. In particular, novel functions of NOX4 in driving cellular metabolic changes have emerged. Alterations in cellular metabolism are a recognized hallmark of the heart's response to physiological and pathological stresses. In this review, we highlight the emerging roles of NOX enzymes as important modulators of cellular intermediary metabolism in the heart, linking stress responses not only to myocardial energetics but also other functions. The novel interplay of NOX-modulated redox signalling pathways and intermediary metabolism in the heart is unravelling a new aspect of the fascinating biology of these enzymes which will inform a better understanding of how they drive adaptive responses. We also discuss the implications of these new findings for therapeutic approaches that target metabolism in cardiac disease.