Free Radical Research最新文献

Stomach adenocarcinoma (STAD) is a highly prevalent and lethal malignancy worldwide, with its occurrence and progression regulated by multiple factors. In recent years, selenoprotein glutathione peroxidase 3 (GPX3) has gained significant attention due to its antioxidant properties and role in cellular oxidative stress regulation across various cancers. Our study delved into the expression of GPX3 in STAD and investigated its impact on tumor cell growth, providing insights into its potential anti-tumor mechanisms. The expression levels of GPX3 were analyzed in STAD tissues sourced from the TCGA database and contrasted with the levels found in normal gastric tissues. The expression levels of GPX3 were contrasted between STAD tissues and normal gastric tissues, and their correlation with patient prognosis was assessed by survival analysis. Additionally, we validated GPX3 expression changes and its effects on tumor cell growth using quantitative PCR (qPCR) and CCK-8 proliferation assays in STAD cell lines (MNK-45, MGC-803, N87, and HGC-27). Our findings suggest that GPX3 expression is significantly downregulated in STAD tissues compared to normal gastric tissues. Survival analysis further reveals that patients with high GPX3 expression exhibit better long-term survival rates, suggesting a potential tumor-suppressive function. In vitro experiments confirmed effective knockdown or overexpression of GPX3 in STAD cell lines. CCK-8 proliferation assays demonstrated that GPX3 overexpression significantly inhibited tumor cell proliferation, whereas GPX3 knockdown promoted cell growth. This study provides new experimental evidence supporting GPX3 as a potential therapeutic target for STAD and offers a theoretical foundation for future molecular-targeted therapies for STAD.

Amino acid metabolism plays a crucial role in tumor biology. The sodium-independent cystine/glutamate exchange system, known as system X_c^-, is significantly activated in cancer cells and plays a role in tumor progression. Copper (Cu), an essential micronutrient, plays a crucial role in physiological processes; however, its accumulation in tumors has been associated with tumor progression. Nonetheless, the relationship between system X_c^--mediated amino acid metabolism and Cu remains inadequately understood. In this study, CuCl₂ treatment resulted in the significant induction of SLC7A11, a light chain subunit of system X_c^-, and glutamate receptor mGluR1 expression in human triple-negative MDA-MB-231 cells. Conversely, FeCl₂ treatment induced the expression of SLC7A11 but not mGluR1, indicating that Cu specifically activated SLC7A11-mediated amino acid metabolism. The investigation focused on the role of Nrf2, a redox-sensitive transcription factor, in the induction of SLC7A11 under conditions of oxidative stress induced by CuCl₂ treatment. Upon treatment with CuCl₂, the nuclear translocation of Nrf2 was observed, and knockdown of Nrf2 significantly suppressed the induction of SLC7A11. Given that the Cu chaperone, antioxidant-1 (Atox1), functions as a Cu-dependent transcription factor, the role of Atox1 in the expression of SLC7A11 was further investigated. Like the effects of Nrf2 knockdown, Atox1 was found to play a pivotal role in the Cu-mediated induction of SLC7A11. Our findings indicate that intratumoral Cu influences the expression of SLC7A11 and may play a role in tumor progression.

Dihydroethidium (DHE) is widely used for superoxide detection, yet reported excitation and emission values vary across studies. To address this, we employed full-spectrum scanning to compare DHE fluorescence between a xanthine oxidase (XO)-based cell-free system and a rotenone-treated cellular model, and to assess factors contributing to spectral shifts. In the XO system, the excitation peak was ∼480 nm, whereas in cells it shifted to ∼520 nm. Riboflavin, flavin mononucleotide (FMN), and flavin adenine dinucleotide (FAD) accounted for this shift, while calcium and bicarbonate ions modulated both peak position and fluorescence intensity. Riboflavin depletion reduced intracellular flavin levels but did not restore the peak to 480 nm, indicating additional roles for FMN and FAD. Among scavengers, only tiron directly inhibited DHE fluorescence in the cell-free system, with enhanced activity in the presence of Ca²⁺ and Mg²⁺. In contrast, responses in cells varied by type and rotenone concentration, suggesting indirect modulation through endogenous antioxidant defenses. Addition of FMN, FAD, or cell lysates to the cell-free system attenuated scavenger efficacy, supporting intracellular interference. These findings demonstrate that riboflavin metabolism and ionic microenvironments critically shape DHE spectral behavior. Accurate interpretation of DHE-based superoxide detection therefore requires prior spectral evaluation to distinguish genuine superoxide signals from cofactor- or ion-dependent effects.

Betulinic acid (BA) is a pentacyclic triterpenoid with broad pharmacological potential and widely recognized for its neuroprotective effects. This study investigated the potential protective effects of this compound on in vitro differentiated human neuroblastoma SH-SY5Y cells against LPS and FeSO₄-induced ferroptosis, apoptosis, neuroinflammation, and dopaminergic cell death, and explored the underlying mechanisms. Differentiated human neuroblastoma SH-SY5Y cells were exposed to LPS and FeSO₄, and the cellular viability was evaluated using the MTT assay. Flow cytometry was performed to assess apoptotic cell death. Additionally, the expression levels of key markers associated with ferroptosis, apoptosis, and other relevant signaling proteins were analyzed through western blotting and Immunocytochemical staining techniques. However, co-exposure with LPS and FeSO₄ resulted in a dose-dependent reduction in cell viability, which was significantly reversed by pretreatment with BA (0.3-30μM). Exposure to LPS and FeSO₄ increased the DMT1, Bax, caspase-3, and alpha-synuclein, and decreased the GPX4, FTH1, SLC7A11, Nrf2, Keap1, HO-1, PARK7, Bcl-2, NeuN, and TH levels, resulting in cell ferroptosis, apoptosis, and dopaminergic cell death. Furthermore, LPS and FeSO₄ significantly increased the expression of IL-6, TNF-α, and phosphorylation of p38, pMAPK, and pNFkB in the cells. Pretreatment with BA markedly suppressed LPS and FeSO₄-induced upregulation of pro-inflammatory cytokines, ferroptosis, apoptosis, and dopaminergic cell death markers. These findings suggest that BA exerts neuroprotection by modulating the GPX4/Nrf2/Keap-1/HO-1 antioxidant defense and p38MAPK/NF-κB inflammatory signaling pathways, highlighting its potential as a therapeutic agent for oxidative stress-related neurodegenerative conditions, such as Parkinson's disease (PD).

Hypoxia-inducible factor (HIF) signaling plays a critical role in immune cell function. Pseudohypoxia is characterized as iron-mediated stabilization of HIF-1α under normoxic conditions, which can be induced by iron chelators. This study explored whether iron chelators exert antitumor effects by enhancing tumor immune responses and elucidating the underlying mechanisms. The iron chelators Super-polyphenol 10 (SP10) and Deferoxamine (DFO) were used to create iron-deficient and pseudohypoxia conditions. Pseudohypoxia induced by iron chelators stimulates IL-2 secretion from T cells and from both human and murine nonsmall cell lung cancer (NSCLC) cell lines (A549, PC-3, and LLC). Administration of SP10 reduced tumor growth when LLC tumors were implanted in C57BL/6 mice; however, this was not observed in immunodeficient RAG1-deficient C57BL/6 mice. SP10 itself did not directly inhibit LLC cells proliferation in vitro, suggesting an activation of the tumor immune response. SP10 synergistically enhanced the efficacy of PD-1 antibody therapy in lung cancer by increasing the number of tumor-infiltrating lymphocytes (TILs). In conclusion, iron chelation-induced pseudohypoxia activates tumor immune responses by directly upregulating HIF-1α, augmenting T cell function, and inducing IL-2 secretion from T cells, and cancer cells, thereby amplifying the immune efficacy of the PD-1 antibody in lung cancer treatment.

MicroRNAs (miRNAs) (miRs) are a small class of endogenous non-coding RNA molecules that play a key role in various physiological and pathological processes. Likewise, oxidative stress can cause damage to many parts of the body and can contribute to disease development. Hence, this review aims to address the crosstalk between reactive oxygen species (ROS) and miRNAs in respiratory diseases. This review begins with an overview of the sources and regulation of free radicals, oxidative stress-mediated lung pathologies, and miRNAs biogenesis. Indeed, growing evidence suggests that miRNAs can modify cellular redox status in both nonmalignant and malignant respiratory diseases. We also discussed ROS-responsive miRNAs that have implications in disease development. Mechanistic pathways by which the complex interplay between miRNAs and ROS occurs have been discussed. Thus, targeting miRNAs may provide potential new strategies to specifically overcome oxidative stress-mediated development of many lung diseases.

In this study, the anti-aging potential of melibiose was examined, and its molecular mechanism was elucidated using Caenorhabditis elegans as a model organism. The findings demonstrated that melibiose at concentrations of 100 μM, 150 μM, and 200 μM significantly increased nematode lifespan by 15.38%, 23.08%, and 30.77% respectively. Additionally, melibiose enhanced resistance against heat and oxidative stress, improved nematode motility, reduced lipofuscin and reactive oxygen species (ROS) accumulation, and increased antioxidant enzyme activity. Through the use of gene-deletion nematodes, transgenic nematodes, RT-qPCR, and metabolomics, it was determined that melibiose potentially exerts its effects through multiple pathways including the insulin signaling pathway (down-regulation of daf-2 and age-1, up-regulation of sod-3 and hsp-16.2), the AMP-activated protein kinase (AMPK) pathway (up-regulation of aak-2), and the JNK pathway (up-regulation of jnk-1). Activation of transcription factors DAF-16, SKN-1, and HSF-1 was observed, moreover, delaying the aging process by promoting autophagy (upregulation of lgg-1 and bec-1) and mitochondrial function (upregulation of hsp-6, hsp-60, and mev-1) to resist oxidative damage. And its anti-aging signature metabolites may be Carbimazole, 4-Hydroxy-2-oxoglutaric acid, and 1,4-Dithiothreitol.

Far-infrared radiation (FIR) induces glutathione peroxidase-1 (GPx-1) expression and enhances microcirculation by upregulating endothelial nitric oxide synthase (eNOS). However, the role of eNOS in FIR-mediated neuroprotection remains unclear. Here, we investigated whether FIR upregulates eNOS and extracellular signal-regulated kinase (ERK) signaling to mitigate recognition memory impairment caused by methamphetamine (MA). FIR significantly reduced MA-induced oxidative stress, which was primarily associated with GPx-1 inhibition. FIR or genetic overexpression of GPx-1 (GPx-1 TG) in mice significantly attenuated the MA-induced reduction in phospho-eNOS (p-eNOS) and phospho-ERK (p-ERK). Triple-label immunostaining revealed colocalization of p-eNOS, p-ERK, and GPx-1 within the same cellular populations in the prefrontal cortex. In non-transgenic (non-TG) mice, FIR exposure improved MA-induced cholinergic and memory deficits. However, FIR did not provide additional cognitive benefits in GPx-1 TG mice, and the GPx-1 inhibitor mercaptosuccinate blocked FIR-mediated cholinergic effects. Inhibitors of eNOS (i.e. L-NAME) and ERK (i.e. U0126) also significantly blocked the FIR-driven memory-enhancing effects in non-TG mice. Unlike L-NAME, which inhibits phosphorylation of both eNOS and ERK, U0126 did not affect FIR-induced eNOS phosphorylation, suggesting that eNOS is an upstream molecule for ERK signaling. Our finding suggests that GPx-1 is an essential mediator of FIR-induced memory enhancement, and that FIR exposure attenuates MA-induced cognitive impairments via cholinergic upregulation associated with GPx-1/eNOS/ERK signaling.

Perturbation in redox status elicits multiple cellular pathways, including those involved in the inflammatory response. A thiol-based molecule (I-152), releasing N-acetyl-cysteine (NAC) and β-mercaptoethylamine (MEA), was exploited as a redox-modulating agent, and its effects on pro-inflammatory cytokine expression and secretion in lipopolysaccharide (LPS)-stimulated macrophages (MΦ) were investigated. I-152 inhibited cytokine gene expression as well as protein secretion of the most important inflammatory cytokines in three different MΦ models in vitro and ex vivo. It alleviated inflammation via the c-Jun/AP-1 and NF-κB signaling pathways, depending on the dose, and regulated NLRP3 inflammasome expression, leading to decreased IL-1β and IL-18 release and reduced pyroptotic cell death. Consequently, the influence of redox-modulated MΦ secretome on the crosstalk with endothelial cells was evaluated. Co-culture experiments between THP-1 MΦ, that had been pretreated with I-152 before LPS stimulation, and Human Vascular Endothelial Cells (HUVECs) showed reduced VCAM/ICAM expression in these cells in concomitance with a less oxidized and inflamed MΦ proteomic portrait. Overall, our findings suggest that I-152 redox modulation could target the AP-1/NLRP3 axis, affecting LPS-induced inflammation in MΦ and influencing HUVEC responses, revealing a complex and bidirectional interchange.

The antioxidant properties of 34 plant alkaloids in gas phase, ethanol and water have been evaluated using density functional theory (DFT). The computations have been made according to three different single electron mechanisms: (1) H-atom transfer (HAT); (2) electron transfer followed by H⁺ transfer (SET-PT); and (3) sequential H⁺-loss electron transfer (SPLET). As a result, the highest antioxidant activity was established for evodiamine. Global reactivity in terms of hardness/softness has been calculated also, as well as Fukui indices of local reactivity. Structural aspects related to H, electron and proton loss have been regarded in sufficient details. In terms of global softness, palmatine, dehydroevodiamine and chelerythrine have been determined as the most reactive molecules, whereas C7 atom of evodiamine has been found to be the most reactive atom. All the findings are in agreement with the recent experimental and theoretical studies on alkaloid antioxidant activity and can be compared with the results for ascorbic acid, which was used as a reference compound.