The Role of Peroxiredoxins in Cancer Development

Druggable upregulated proteins in EWS-FLI-driven Ewing sarcoma as emerging new therapeutic targets

Ewing sarcoma (ES) is a highly aggressive soft tissue tumor that primarily affects the long bones of children and young adults. It is distinguished by a characteristic chromosomal translocation between the Ewing sarcoma breakpoint region 1 (EWS) gene and the erythroblast transformation-specific (ETS) family of genes, most commonly resulting in the EWS-friend leukemia integration 1 (EWS-FLI1) fusion gene. This translocation is observed in approximately 80%-85% of ES cases. This fusion gene encodes a non-physiological chimeric fusion protein that plays a central role in tumorigenesis by interacting with numerous partner proteins. Several studies have demonstrated the tumorigenic potential of the EWS-FLI1 protein when transfected into non-cancer cell lines. However, targeting EWS-FLI1 directly remains a significant challenge, as no drug to date has been reported to bind to and inhibit its activity effectively. An alternative therapeutic strategy involves targeting key overexpressed protein complexes implicated in ES tumorigenesis, many of which may be downstream interacting partners of EWS-FLI1. This review explores emerging protein targets as potential therapeutic avenues in ES treatment.

Role of the sulfur-containing amino acid-ROS axis in cancer chemotherapeutic drug resistance

Chemotherapeutic drug resistance remains a major barrier to effective cancer treatment. Drug resistance could be driven in part by adaptive redox remodeling of cancer cells. Paradoxically, drug-resistant malignancies exhibit elevated reactive oxygen species (ROS), as well as amplified antioxidant defenses, which enable cancer cell survival under therapeutic stress. Central to this adaptation is glutathione (GSH), the predominant cellular antioxidant, whose synthesis relies on sulfur-containing amino acids (SAAs) - methionine and cysteine. This review delineates the metabolic interplay between methionine and cysteine in the transsulfuration pathway, highlighting their roles as precursors in GSH biosynthesis. We systematically summarize the key enzymes that drive GSH production and their contributions to resistance against platinum-based drugs and other chemotherapeutics. In addition to GSH synthesis, we summarize the roles of GSH antioxidant systems, including glutathione peroxidases (GPXs), peroxiredoxins (PRDXs), and thioredoxins (TRXs), which are critical in chemotherapeutic drug resistance through ROS scavenging. Recent advances reveal that targeting these enzymes, by pharmacologically inhibiting transsulfuration enzymes or disrupting GSH-dependent antioxidant cascades, can sensitize resistant cancer cells to ROS-mediated therapies. These findings not only clarify the mechanistic links between SAA metabolism and redox adaptation but also provide practical approaches to overcome chemotherapeutic drug resistance. By analyzing metabolic and redox vulnerabilities, this review highlights the therapeutic potential to restore chemosensitivity, offering new options in precision oncology medicine.

Peripheral blood proteome biomarkers distinguish immunosuppressive features of cancer progression

Immune status critically affects cancer progression and therapy responses. This study aimed to identify plasma proteome changes in immunosuppressive cancer and potential biomarkers predicting systemic immunosuppression. Mouse models of syngeneic breast tumors (benign 67NR and malignant 4T1) were used to collect plasma samples. Plasma samples from naive mice and both early- and late-stage tumor-bearing mice were subjected to liquid chromatography-mass spectrometry (LC-MS) analysis. 4T1-bearing mice showed systemic immunosuppression characterized by significant generation of myeloid-derived suppressor cells (MDSCs) as early as 7 days after tumor implantation, unlike 67NR tumors. LC-MS identified 1086 proteins across the five experimental groups, with 27 proteins showing group-specific expression in 4T1 blood compared with 67NR blood. Immune-related proteins osteopontin, lactotransferrin, calreticulin, and peroxiredoxin 2 were selected as potential biomarkers of MDSC-producing breast cancer. These markers were expressed in cancer cells or MDSC in the 4T1 model, and osteopontin and peroxiredoxin 2 were associated with low survival probability and high recurrence in patients with triple-negative breast cancer. Our findings suggest that MDSC-producing immunosuppressive cancers have unique plasma proteomes, offering additional insights into cancer immune status.

Peroxiredoxin 1 modulates oxidative stress resistance and cell apoptosis through stemness in liver cancer under non-thermal plasma treatment

The role of peroxiredoxin 1 (PRDX1), a crucial enzyme that reduces reactive oxygen and nitrogen species levels in HepG2 human hepatocellular carcinoma (HCC) cells, in the regulation of HCC cell stemness under oxidative stress and the underlying mechanisms remain largely unexplored. Here, we investigated the therapeutic potential of non-thermal plasma in targeting cancer stem cells (CSCs) in HCC, focusing on the mechanisms of resistance to oxidative stress and the role of PRDX1. By simulating oxidative stress conditions using the plasma-activated medium, we found that a reduction in PRDX1 levels resulted in a considerable increase in HepG2 cell apoptosis, suggesting that PRDX1 plays a key role in oxidative stress defense mechanisms in CSCs. Furthermore, we found that HepG2 cells had higher spheroid formation capability and increased levels of stem cell markers (CD133, c-Myc, and OCT-4), indicating strong stemness. Interestingly, PRDX1 expression was notably higher in HepG2 cells than in other HCC cell types such as Hep3B and Huh7 cells, whereas the expression levels of other PRDX family proteins (PRDX 2-6) were relatively consistent. The inhibition of PRDX1 expression and peroxidase activity by conoidin A resulted in markedly reduced stemness traits and increased cell death rate. Furthermore, in a xenograft mouse model, PRDX1 downregulation considerably inhibited the formation of solid tumors after plasma-activated medium (PAM) treatment. These findings underscore the critical role of PRDX 1 in regulating stemness and apoptosis in HCC cells under oxidative stress, highlighting PRDX1 as a promising therapeutic target for NTP-based treatment in HCC.

PRDX1 Interfering Peptide Disrupts Amino Acids 70-90 of PRDX1 to Inhibit the TLR4/NF-κB Signaling Pathway and Attenuate Neuroinflammation and Ischemic Brain Injury

Ischemic stroke ranks among the leading causes of death and disability in humans and is accompanied by motor and cognitive impairment. However, the precise mechanisms underlying injury after stroke and effective treatment strategies require further investigation. Peroxiredoxin-1 (PRDX1) triggers an extensive inflammatory cascade that plays a pivotal role in the pathology of ischemic stroke, resulting in severe brain damage from activated microglia. In the present study, we used molecular dynamics simulation and nuclear magnetic resonance to detect the interaction between PRDX1 and a specific interfering peptide. We used behavioral, morphological, and molecular experimental methods to demonstrate the effect of PRDX1-peptide on cerebral ischemia-reperfusion (I/R) in mice and to investigate the related mechanism. We found that PRDX1-peptide bound specifically to PRDX1 and improved motor and cognitive functions in I/R mice. In addition, pretreatment with PRDX1-peptide reduced the infarct area and decreased the number of apoptotic cells in the penumbra. Furthermore, PRDX1-peptide inhibited microglial activation and downregulated proinflammatory cytokines including IL-1β, IL-6, and TNF-α through inhibition of the TLR4/NF-κB signaling pathway, thereby attenuating ischemic brain injury. Our findings clarify the precise mechanism underlying PRDX1-induced inflammation after ischemic stroke and suggest that the PRDX1-peptide can significantly alleviate the postischemic inflammatory response by interfering with PRDX1 amino acids 70-90 and thereby inhibiting the TLR4/NF-κB signaling pathway. Our study provides a theoretical basis for a new therapeutic strategy to treat ischemic stroke.

Gut microbial and metabolomics profiles reveal the potential mechanism of fecal microbiota transplantation in modulating the progression of colitis-associated colorectal cancer in mice

PURPOSE

Intestinal flora promotes the pathogenesis of colorectal cancer (CRC) through microorganisms and their metabolites. This study aimed to investigate the composition of intestinal flora in different stages of CRC progression and the effect of fecal microbiota transplantation (FMT) on CRC mice.

METHODS

The fecal microbiome from healthy volunteers (HC), colorectal adenoma (CRA), inflammatory bowel disease (IBD), and CRC patients were analyzed by 16s rRNA gene sequencing. In an azoxymethane (AOM)/dextran-sulfate-sodium (DSS)-induced CRC mouse, the effect of FMT from HC, CRA, CRC, and IBD patients on CRC mice was assessed by histological analysis. Expression of inflammation- EMT-associated proteins and Wnt/β-catenin pathway were assessed using qRT-PCR and western blot. The ratio of the fecal microorganisms and metabolomics alteration after FMT were also assessed.

RESULT

Prevotella, Faecalibacterium, Phascolarctobacterium, Veillonella, Alistipes, Fusobacterium, Oscillibacter, Blautia, and Ruminococcus abundance was different among HC, IBD, CRC, and CRA patients. HC-FMT alleviated disease progression and inflammatory response in CRC mice, inhibited splenic T help (Th)1 and Th17 cell numbers, and suppressed the EMT and Wnt/β-catenin pathways in tumor tissues of CRC mice. IBD-FMT, CRA-FMT, and CRC-FMT played deleterious roles; the CRC-FMT mice exhibited the most malignant phenotype. Compared with the non-FMT CRC mice, Muribaculaceae abundance was lower after FMT, especially lowest in the IBD-FMT group; while Lactobacillus abundance was higher after FMT and especially high in HC-FMT. Akkermansia and Ileibacterium abundance increased after FMT-HC compared to other groups. Metabolite correlation analysis revealed that Muribaculaceae abundance was significantly correlated with metabolites such as Betaine, LysoPC, and Soyasaponin III. Lactobacillus abundance was positively correlated with Taurocholic acid 3-sulfate, and Ileibacterium abundance was positively correlated with Linoleoyl ethanolamide.

CONCLUSION

The different intestinal microbiota communities of HC, IBD, CRA, and CRC patients may be attributed to the different modulation effects of FMT on CRC mice. CRC-FMT promoted, while HC-FMT inhibited the progress of CRC. Increased linoleoyl ethanolamide levels and abundance of Muribaculaceae, Akkermansia, and Ileibacterium and reduced Fusobacterium might participate in inhibiting CRC initiation and development. This study demonstrated that FMT intervention could restore the intestinal microbiota and metabolomics of CRC mice, suggesting FMT as a potential strategy for CRC therapy.

A New Fluorescent Method for Measuring Peroxiredoxin Enzyme Activity Using Monobromobimane

A novel fluorometric method is presented for accurately quantifying peroxiredoxin (Prx) enzyme activity in vitro. The rate-limiting step in the Prx-catalyzed reaction is the dissociation of peroxide. To avoid interference from catalase, we developed an assay using tert-butyl hydroperoxide (t-BOOH) as a substrate for specific Prx activity measurement. The assay involves incubating the enzyme substrates 1,4-dithio-DL-threitol (DTT) and t-BOOH in a suitable buffer at 37 °C for 10 min in a known volume of Prx enzyme. Following incubation, the reagent monobromobimane (mBB) is added to terminate the enzymatic reaction and produce a fluorescent product. Prx activity is subsequently determined by measuring thiol fluorescence, with reaction conditions optimized using a Bland-Altman plot. The efficacy of this novel protocol was rigorously validated by comparing Prx activity measurements from paired samples with those generated by a reference assay. A correlation coefficient of 0.995 was observed between the two methods, demonstrating superior precision and reliability compared to existing methods. The mBB-Prx protocol offers a significant safety advantage by using t-BOOH as a substrate for Prx activity measurement. As catalase does not catalyze t-BOOH dissociation, including sodium azide is unnecessary. Moreover, the method obviates the need for concentrated acids to terminate the Prx enzymatic reaction, as the mBB reagent efficiently inhibits Prx activity. This streamlined approach simplifies the assay and significantly improves its safety and usability, providing users with a reliable and convenient tool. The convenience of this method allows users to focus on their research without worrying about safety or complex procedures.

Redox Homeostasis and Molecular Biomarkers in Precision Therapy for Cardiovascular Diseases

Precision medicine is envisioned as the future of cardiovascular healthcare, offering a more tailored and effective method for managing cardiovascular diseases compared to the traditional one-size-fits-all approaches. The complex role of oxidative stress in chronic diseases within the framework of precision medicine was carefully explored, delving into the cellular redox status and its critical involvement in the pathophysiological complexity of cardiovascular diseases (CVDs). The review outlines the mechanisms of reactive oxygen species generation and the function of antioxidants in maintaining redox balance. It emphasizes the elevated reactive oxygen species concentrations observed in heart failure and their detrimental impact on cardiovascular health. Various sources of ROS within the cardiovascular system are examined, including mitochondrial dysfunction, which contributes to oxidative stress and mitochondrial DNA degradation. The article also addresses oxidative stress's role in myocardial remodeling, a process pivotal to the progression of heart diseases. By integrating these aspects, the review underscores the importance of redox homeostasis and identifies molecular biomarkers that can enhance precision therapy for CVDs. The insights provided aim to pave the way for targeted therapeutic strategies that mitigate oxidative stress, thereby improving patient outcomes in cardiovascular medicine.

Mitochondrial Physiology of Cellular Redox Regulations

Mitochondria (mt) represent the vital hub of the molecular physiology of the cell, being decision-makers in cell life/death and information signaling, including major redox regulations and redox signaling. Now we review recent advances in understanding mitochondrial redox homeostasis, including superoxide sources and H2O2 consumers, i.e., antioxidant mechanisms, as well as exemplar situations of physiological redox signaling, including the intramitochondrial one and mt-to-cytosol redox signals, which may be classified as acute and long-term signals. This review exemplifies the acute redox signals in hypoxic cell adaptation and upon insulin secretion in pancreatic beta-cells. We also show how metabolic changes under these circumstances are linked to mitochondrial cristae narrowing at higher intensity of ATP synthesis. Also, we will discuss major redox buffers, namely the peroxiredoxin system, which may also promote redox signaling. We will point out that pathological thresholds exist, specific for each cell type, above which the superoxide sources exceed regular antioxidant capacity and the concomitant harmful processes of oxidative stress subsequently initiate etiology of numerous diseases. The redox signaling may be impaired when sunk in such excessive pro-oxidative state.

Conditional knockout mouse model reveals a critical role of peroxiredoxin 1 in oral leukoplakia carcinogenesis

Peroxiredoxin 1 (Prx1) is an antioxidant protein that may promote the carcinogenesis in oral leukoplakia (OLK). To investigate the effect of Prx1 on the oral mucosal epithelium of OLK, we generated a Prx1 conditional knockout (cKO) mouse model. The mRNA and gRNA were generated using the clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) technique. An infusion cloning method was used to construct a homologous recombination vector. To obtain the F0 generation mice, fertilized eggs of C57BL/6J mice were microinjected with Cas9 mRNA, gRNA, and a donor vector. Polymerase chain reaction (PCR) amplification and sequencing were used to identify F1 generation mice. Using the cyclization recombination-enzyme-locus of the X-overP1 (Cre-loxP) system, we created a Prx1 cKO mouse model, and the effectiveness of the knockout was confirmed through immunohistochemistry. We examined the influence of Prx1 knockout on the occurrence of OLK in mice by constructing a model of tongue mucosa carcinogenesis induced by 4-nitroquinoline-1-oxide (4NQO). Prx1 modification was present in the F1 generation, as evidenced by PCR amplification and sequencing. Prx1flox/flox: Cre + mice exhibited normal growth and fertility. Immunohistochemical analysis revealed that tongue epithelial cells in Prx1flox/flox: Cre + mice displayed a distinct deletion of Prx1. An examination of the heart, liver, spleen, lung, and kidney tissues revealed no visible histological changes. Histological analysis showed a reduction in the occurrence of the malignant transformation of OLK in the tongue tissues of Prx1flox/flox: Cre + mice. Ki67 immunostaining showed that Prx1 knockout significantly inhibited cell proliferation in the tongue epithelial. Our research developed a conditional knockout mouse model for Prx1. The obtained results provide insights into the function of Prx1 in the development of oral cancer and emphasize its potential as a therapeutic target for precancerous oral lesions.

Changes Induced by P2X7 Receptor Stimulation of Human Glioblastoma Stem Cells in the Proteome of Extracellular Vesicles Isolated from Their Secretome

Extracellular vesicles (EVs) are secreted from many tumors, including glioblastoma multiforme (GBM), the most common and lethal brain tumor in adults, which shows high resistance to current therapies and poor patient prognosis. Given the high relevance of the information provided by cancer cell secretome, we performed a proteomic analysis of microvesicles (MVs) and exosomes (EXOs) released from GBM-derived stem cells (GSCs). The latter, obtained from the brain of GBM patients, expressed P2X7 receptors (P2X7Rs), which positively correlate with GBM growth and invasiveness. P2X7R stimulation of GSCs caused significant changes in the EV content, mostly ex novo inducing or upregulating the expression of proteins related to cytoskeleton reorganization, cell motility/spreading, energy supply, protection against oxidative stress, chromatin remodeling, and transcriptional regulation. Most of the induced/upregulated proteins have already been identified as GBM diagnostic/prognostic factors, while others have only been reported in peripheral tumors. Our findings indicate that P2X7R stimulation enhances the transport and, therefore, possible intercellular exchange of GBM aggressiveness-increasing proteins by GSC-derived EVs. Thus, P2X7Rs could be considered a new druggable target of human GBM, although these data need to be confirmed in larger experimental sets.

The Tumor Suppressor SOCS1 Diminishes Tolerance to Oxidative Stress in Hepatocellular Carcinoma

SOCS1 is a tumor suppressor in hepatocellular carcinoma (HCC). Recently, we showed that a loss of SOCS1 in hepatocytes promotes NRF2 activation. Here, we investigated how SOCS1 expression in HCC cells affected oxidative stress response and modulated the cellular proteome. Murine Hepa1-6 cells expressing SOCS1 (Hepa-SOCS1) or control vector (Hepa-Vector) were treated with cisplatin or tert-butyl hydroperoxide (t-BHP). The induction of NRF2 and its target genes, oxidative stress, lipid peroxidation, cell survival and cellular proteome profiles were evaluated. NRF2 induction was significantly reduced in Hepa-SOCS1 cells. The gene and protein expression of NRF2 targets were differentially induced in Hepa-Vector cells but markedly suppressed in Hepa-SOCS1 cells. Hepa-SOCS1 cells displayed an increased induction of reactive oxygen species but reduced lipid peroxidation. Nonetheless, Hepa-SOCS1 cells treated with cisplatin or t-BHP showed reduced survival. GCLC, poorly induced in Hepa-SOCS1 cells, showed a strong positive correlation with NFE2L2 and an inverse correlation with SOCS1 in the TCGA-LIHC transcriptomic data. A proteomic analysis of Hepa-Vector and Hepa-SOCS1 cells revealed that SOCS1 differentially modulated many proteins involved in diverse molecular pathways, including mitochondrial ROS generation and ROS detoxification, through peroxiredoxin and thioredoxin systems. Our findings indicate that maintaining sensitivity to oxidative stress is an important tumor suppression mechanism of SOCS1 in HCC.

Pitfalls of Mitochondrial Redox Signaling Research

Redox signaling from mitochondria (mt) to the cytosol and plasma membrane (PM) has been scarcely reported, such as in the case of hypoxic cell adaptation or (2-oxo-) 2-keto-isocaproate (KIC) β-like-oxidation stimulating insulin secretion in pancreatic β-cells. Mutual redox state influence between mitochondrial major compartments, the matrix and the intracristal space, and the cytosol is therefore derived theoretically in this article to predict possible conditions, when mt-to-cytosol and mt-to-PM signals may occur, as well as conditions in which the cytosolic redox signaling is not overwhelmed by the mitochondrial antioxidant capacity. Possible peroxiredoxin 3 participation in mt-to-cytosol redox signaling is discussed, as well as another specific case, whereby mitochondrial superoxide release is diminished, whereas the matrix MnSOD is activated. As a result, the enhanced conversion to H2O2 allows H2O2 diffusion into the cytosol, where it could be a predominant component of the H2O2 release. In both of these ways, mt-to-cytosol and mt-to-PM signals may be realized. Finally, the use of redox-sensitive probes is discussed, which disturb redox equilibria, and hence add a surplus redox-buffering to the compartment, where they are localized. Specifically, when attempts to quantify net H2O2 fluxes are to be made, this should be taken into account.

Gender Differences in Oxidative Stress in Relation to Cancer Susceptibility and Survival

Genetic, developmental, biochemical, and environmental variables interact intricately to produce sex differences. The significance of sex differences in cancer susceptibility is being clarified by numerous studies. Epidemiological research and cancer registries have revealed over the past few years that there are definite sex variations in cancer incidence, progression, and survival. However, oxidative stress and mitochondrial dysfunction also have a significant impact on the response to treatment of neoplastic diseases. Young women may be more protected from cancer than men because most of the proteins implicated in the regulation of redox state and mitochondrial function are under the control of sexual hormones. In this review, we describe how sexual hormones control the activity of antioxidant enzymes and mitochondria, as well as how they affect several neoplastic diseases. The molecular pathways that underlie the gender-related discrepancies in cancer that have been identified may be better understood, which may lead to more effective precision medicine and vital information on treatment options for both males and females with neoplastic illnesses.

Oxidative Stress Inducers in Cancer Therapy: Preclinical and Clinical Evidence

Reactive oxygen species (ROS) are metabolic byproducts that regulate various cellular processes. However, at high levels, ROS induce oxidative stress, which in turn can trigger cell death. Cancer cells alter the redox homeostasis to facilitate protumorigenic processes; however, this leaves them vulnerable to further increases in ROS levels. This paradox has been exploited as a cancer therapeutic strategy with the use of pro-oxidative drugs. Many chemotherapeutic drugs presently in clinical use, such as cisplatin and doxorubicin, induce ROS as one of their mechanisms of action. Further, various drugs, including phytochemicals and small molecules, that are presently being investigated in preclinical and clinical studies attribute their anticancer activity to ROS induction. Consistently, this review aims to highlight selected pro-oxidative drugs whose anticancer potential has been characterized with specific focus on phytochemicals, mechanisms of ROS induction, and anticancer effects downstream of ROS induction.