Search Results (126)

To explore the potential seed compounds from natural products as anticancer agents against small-cell lung cancer (SCLC), the underground parts of Agapanthus africanus, a plant commonly used for ornamental purposes, were investigated. Three spirostan-type steroidal glycosides (1–3) were isolated and identified by nuclear magnetic resonance spectral analysis. Compounds 1–3 exhibited cytotoxicity against SBC-3 human SCLC cells, with IC₅₀ values of 0.56, 1.4, and 7.4 µM, respectively. Compound 1, also known an agapanthussaponin A, demonstrated the most potent cytotoxicity among the isolated compounds and was evaluated for its apoptosis- and ferroptosis-inducing activities. Compound 1 arrested the cell cycle of SBC-3 cells in the G₂/M phase and induced apoptosis primarily via the mitochondrial pathway, characterized by caspases-3 and -9 activation, loss of mitochondrial membrane potential, and overproduction of reactive oxygen species. Additionally, 1 triggered ferroptosis via a dual mechanism consisting of enhanced cellular iron uptake through upregulation of transferrin and transferrin receptor 1 expression and impaired glutathione synthesis via downregulation of both xCT and glutathione peroxidase 4 expression. Compound 1 induces cell death via the apoptosis and ferroptosis pathways, suggesting its promise as a seed compound for the development of anticancer therapeutics against SCLC. Full article

Background and Purpose: Glioblastoma remains a therapeutic challenge with a poor prognosis despite multimodal treatments. Reporter-based magnetic resonance imaging (MRI) offers a promising approach for tumor visualization, but its efficacy depends on sufficient reporter gene expression. This study aimed to develop a chimeric element-regulated ferritin heavy chain 1 (FTH1) reporter system to enhance MRI-based glioma detection while enabling targeted therapy via transferrin receptor (TfR)-mediated drug delivery. Methods: Using gene cloning techniques, we constructed a chimeric FTH1 expression system comprising tumor-specific PEG3 promoter (transcriptional control), bFGF-2 5′UTR (translational enhancement), and WPRE (mRNA stabilization). Lentiviral vectors delivered constructs to U251 glioblastoma cells and xenografts. FTH1/TfR expression was validated by Western blot and immunofluorescence. Iron accumulation was assessed via Prussian blue staining and TEM. MRI evaluated T2 signal changes. Transferrin-modified doxorubicin liposomes (Tf-LPD) were characterized for size and drug loading and tested for cellular uptake and cytotoxicity in vitro. In vivo therapeutic efficacy was assessed in nude mouse models through tumor volume measurement, MR imaging, and histopathology. Results: The chimeric system increased FTH1 expression significantly over PEG3-only controls (p < 0.01), with an increase of nearly 1.5-fold compared to the negative and blank groups and approximately a two-fold increase relative to the single promoter group, with corresponding TfR upregulation. Enhanced iron accumulation reduced T2 relaxation times significantly (p < 0.01), improving MR contrast. Tf-LPD (115 nm, 70% encapsulation) showed TfR-dependent uptake, inducing obvious apoptosis in high-TfR cells compared with that in controls. In vivo, Tf-LPD reduced tumor growth markedly in chimeric-system xenografts versus controls, with concurrent MR signal attenuation. Conclusions: The chimeric regulatory strategy overcomes limitations of single-element systems, demonstrating significant potential for integrated glioma theranostics. Its modular design may be adaptable to other reporter genes and malignancies. Full article

Tracking T cells in vivo using MRI is a major challenge due to the difficulty of labeling these non-phagocytic cells with a sufficient contrast agent to generate a detectable signal change. In this study, we explored CD4-Superparamagnetic iron oxide nanoparticles (SPION), which is commonly used in magnetic cell sorting, as a potential receptor-mediated, specific CD4⁺ T cell MRI labeling agent. We optimized the labeling protocol for maximal CD4⁺ cell labeling and viability. Cell health was confirmed with trypan blue assay, and labeling efficacy was confirmed with Prussian blue staining, transmission electron microscopy, and MRI of labeled cell pellets. Key cell functionality was assessed by flow cytometry. Next, CD4-SPION-labeled T cells or unlabeled T cells were delivered via intravenous injection in naïve mice. Liver MRIs pre-, 24 h, and 72 h post-T cell injection were performed to determine in vivo tracking ability. Our results show that CD4-SPION induces significant attenuation of T2 signals in a concentration-dependent manner, confirming their potential as an effective MRI contrast agent. In vitro, analyses showed that CD4⁺ T cells were able to uptake CD4-SPION without affecting cellular activity and key functions, as evidenced by Prussian blue staining and flow cytometric analysis of IL-2 receptor and the IL-7 receptor α-chains, CD69 upregulation, and IFN-γ secretion. In vivo, systemically distributed CD4-SPION-labeled T cells could be tracked in the liver at 24 and 72 h after injection, contrary to controls. Histological staining of tissue sections validated the findings. Our results showed that SPION CD4⁺ T cell sorting coupled with longitudinal MR imaging is a valid method to track CD4⁺ T cells in vivo. This safe, specific, and sensitive approach will facilitate the use of SPION as an MRI contrast agent in clinical practice, allowing for non-invasive tracking of adoptive cell therapies in multiple disease conditions. Full article

Plasma non-transferrin-bound iron (NTBI) comprises multiple subspecies, classified by their composition, chemical reactivity, and susceptibility to chelation. The redox-active and chelatable fraction of NTBI is referred to as labile plasma iron (LPI). The pathophysiological significance of NTBI and LPI lies in their ability to enter cells via alternative transport pathways that are not regulated by the transferrin receptor system or by cellular iron levels. Several mechanisms have been proposed for their cellular entry, including the hijacking of divalent metal transporters and passive diffusion. This unregulated uptake can lead to iron accumulation in vulnerable tissues such as the liver and the heart. NTBI and LPI bypassing normal cellular control mechanisms can rapidly exceed the cell’s capacity to safely store excess iron, leading to toxicity. Both NTBI and LPI contribute to oxidative stress by participating in free-radical-generating reactions. However, LPI concentration in the bloodstream may be differentially affected by the mode and extent of iron overload, the presence of residual serum iron-binding activity, and the antioxidant capacity of individual sera. In summary, both NTBI and LPI contribute to iron-mediated toxicity but differ in terms of reactivity, availability, and pathogenic potential depending on the pathophysiological conditions that influence the degree of toxicity. Full article

Background: Nanomedicine approaches for cancer therapy face significant challenges, including a poor tumor accumulation, limited therapeutic efficacy, and systemic toxicity. We hypothesized that controlling the clustering of poly(acrylic acid-co-maleic acid) (PAM)-coated superparamagnetic iron oxide nanoparticles (SPIONs) would enhance their magnetic properties for improved targeting, while enabling a pH-responsive drug release in tumor microenvironments. Methods: PAM-stabilized SPION clusters were synthesized via arrested precipitation, characterized for physicochemical and magnetic properties, and evaluated for doxorubicin loading and pH-dependent release. A dual targeting approach combining antibody conjugation with magnetic guidance was assessed in cellular models, including a novel alternating magnetic field (AMF) pre-treatment protocol. Results: PAM-SPION clusters demonstrated controlled size distributions (60–100 nm), excellent colloidal stability, and enhanced magnetic properties, particularly for larger crystallites (13 nm). The formulations exhibited a pH-responsive drug release (8.5% at pH 7.4 vs. 14.3% at pH 6.5) and a significant enhancement of AMF-triggered release (17.5%). The dual targeting approach achieved an 8-fold increased cellular uptake compared to non-targeted formulations. Most notably, the novel AMF pre-treatment protocol demonstrated an 87% improved therapeutic efficacy compared to conventional post-treatment applications. Conclusions: The integration of targeting antibodies, magnetic guidance, and a pH-responsive PAM coating creates a versatile theranostic platform with significantly enhanced drug delivery capabilities. The unexpected synergistic effect of the AMF pre-treatment represents a promising new approach for improving the therapeutic efficacy of nanoparticle-based cancer treatments. Full article

Superparamagnetic iron oxide (SPIO) nanoparticles are a promising platform for drug delivery and magnetic resonance imaging (MRI). However, complement activation and immune recognition remain major barriers to their clinical translation. Previously, we reported that dextran-coated SPIO nanoworms (NWs) trigger potent complement activation and infusion reactions. Here, we systematically map the temporal sequence of immune events following SPIO NW administration, including C3 opsonization, granulocyte uptake, and cytokine release. In both in vitro and in vivo models, C3 deposition occurred rapidly, peaking at approximately 5 min post-incubation or post-injection. Higher Fe/plasma ratios led to reduced C3 deposition per particle, although the absolute amount of C3 bound was greater in vivo than in vitro. Notably, C3 dissociation from the particle surface exhibited a consistent half-life of ~14 min, independent of the NW injected dose and circulation time. Immune uptake by blood granulocytes was delayed relative to opsonization, becoming prominent only at 60 min post-injection. Further, cytokine release, measured by plasma IL-6 levels, displayed an even slower profile, with peak expression at 6 h post-injection. Together, these results reveal a distinct sequential immune response to SPIO NWs: rapid C3 opsonization, delayed cellular uptake, and late cytokine response. Understanding these dynamics provides a basis for developing strategies to inhibit complement activation and improve the hemocompatibility of SPIO-based theranostic agents. Full article

In plants, ferric-chelate reductase (FRO) plays a critical role in mediating extracellular iron (Fe) reduction, a process essential for cellular Fe homeostasis and abiotic stress tolerance. However, the biological functions and regulatory mechanisms of FRO proteins in fruit crops remain poorly characterized. Here, six VvFRO genes were identified in the table grape cultivar ‘Yanhong’. Transcriptional analysis revealed that root expression of these genes was mainly induced under Fe deficiency, Fe depletion, NaCl stress, and PEG-induced drought stress, respectively, but remained unchanged by low temperature (4 °C) or heat treatment (45 °C). Among them, VvFRO3 exhibited the highest constitutive expression, predominantly in leaves, and was significantly up-regulated under Fe deficiency, Fe depletion, or NaCl treatment. Functional complementation assays demonstrated that heterologous overexpression of VvFRO3 in the Arabidopsis thaliana fro2 knockout mutant rescued its growth retardation phenotype, particularly under Fe-deficient conditions. This study advances our understanding of Fe uptake, transport, and homeostasis mechanisms in perennial fruit crops. Full article

Sex steroid hormones and systemic iron metabolism are emerging as modulators of colorectal cancer (CRC) development and progression. However, information linking systemic factors to tumor characteristics and epithelial–mesenchymal transition (EMT) is limited, particularly in a sex-specific context. We measured serum levels of sex hormones [testosterone, estradiol, progesterone, Luteinizing Hormone (LH), Follicle-Stimulating Hormone (FSH), Carcinoembryonic antigen (CEA)] and iron-related biomarkers (iron, transferrin, ferritin, % transferrin saturation, ceruloplasmin, and the ceruloplasmin/transferrin ratio) in 82 CRC patients and 31 healthy controls. EMT-related proteins [mediator of ErbB2-driven cell motility 1 (MEMO1), E-cadherin, fibronectin, vimentin, and vinculin] were quantified by Western blotting in tumor and adjacent normal mucosa. Non-parametric tests and Spearman correlations were applied, stratified by sex and corrected for age and anemia where appropriate. Progesterone levels were significantly lower in male CRC patients (median 0.17 ng/mL vs. 0.20 ng/mL, p = 0.04) and higher in female patients (0.17 ng/mL vs. 0.10 ng/mL, p = 0.0077) compared with controls. The iron-related biomarkers indicated a pattern of iron deficiency, including in non-anemic patients, with reduced % transferrin saturation (p < 0.01) and an elevated ceruloplasmin/transferrin ratio (p = 0.02). Correlations were found between iron status, tumor stage, and hormonal levels. Progesterone correlated with EMT protein expression in healthy mucosa (e.g., fibronectin in females: ρ = 0.567, p = 0.014; vimentin in males: ρ = −0.446, p = 0.007), but not in tumor tissue. In the healthy mucosa of male patients, ceruloplasmin/transferrin correlated with MEMO1 (ρ = 0.419, p = 0.04), vinculin (ρ = 0.299, p = 0.041), and vimentin (ρ = 0.394, p = 0.07); transferrin levels inversely correlated with MEMO1 expression (ρ = −0.392, p = 0.032), and vimentin showed a positive correlation with serum iron (ρ = 0.350, p = 0.043). Furthermore, fibronectin expression inversely correlated with iron in the sole tumor tissue of female patients (ρ = −0.366, p = 0.040). These findings support the role of sex hormones and iron metabolism in CRC biology, suggesting that EMT might be accompanied by altered iron uptake and redox remodeling, which can enhance cellular motility and the metastatic potential. Full article

The uptake and utilization of iron by bacteria must be strictly controlled. The ferric uptake regulator (Fur) is a global transcription factor widely present in bacteria that can perceive cellular iron levels and adjust the expressions of various genes accordingly. Our earlier research demonstrated that the knockdown of the fur gene in Vibrio splendidus significantly reduced its lethality to Apostichopus japonicus. Although the functions and mechanisms of Fur in regulating bacterial virulence genes have been extensively studied, its virulence regulatory network during V. splendidus pathogenesis in A. japonicus remains unclear. In this article, transcriptome sequencing analysis of V. splendidus under different iron conditions reveals substantial differential gene expressions in the simulated pathogenic environments, identifying 1185 differentially expressed genes, including 198 downregulated and 987 upregulated genes. Comparative analysis between wild-type and Vsfur knockdown strains shows that Vsfur knockdown altered the expression of 3593 genes in V. splendidus, with the most significant differential expression observed under simulated pathogenic conditions (1030 upregulated and 72 downregulated). KEGG enrichment analysis indicates that Vsfur knockdown caused significant gene enrichment in the flagellar assembly pathway and bacterial secretion system, critically impairing flagellar synthesis and secretion system function in V. splendidus. Eight genes selected for qRT-PCR validation showed expression levels in line with the RNA-seq results. Consistent with the transcriptomic results, Vsfur knockdown resulted in reduced antioxidant capacity, bacterial competitiveness, and cytotoxicity in V. splendidus. These findings elucidate the virulence regulatory mechanism of Fur in V. splendidus and provide a reference for understanding the occurrence of A. japonicus skin ulcer syndrome. Full article

Sertoli cell-only (SCO) tubules are a histologic pattern characterized by the absence of germ cells within seminiferous tubules, leading to infertility in both humans and dogs. While its association with testicular tumors has been documented, the role of iron metabolism in SCO tubules remains unclear. This study investigates the immunolabeling of key iron-related proteins (Transferrin Receptor 1, Transferrin Receptor 2, and Ferritin Heavy chain 1) and Proliferating Cell Nuclear Antigen (PCNA) in canine SCO tubules within distinct microenvironments: seminomas, Sertoli cell tumors, and isolated. We confirm the presence and distribution of iron-related proteins in Sertoli cells as a part of a Sertoli cell-only pattern across different microenvironments. Our findings suggest a potential increase in iron uptake in association with tumors, and the cytoplasmic PCNA immunolabeling suggests a preferential activation of cell survival rather than proliferation, potentially facilitating neoplastic transformation. In contrast, Sertoli cells in the isolated Sertoli cell-only pattern exhibit nuclear PCNA immunolabeling, possibly correlated to the state of immaturity of Sertoli cells. These findings highlight the role of iron homeostasis and apoptosis in testicular tumorigenesis. Immunohistochemistry revealed that Sertoli cells in SCO tubules actively uptake iron in all conditions, yet their capacity to utilize it for proliferation appears restricted. Interestingly, PCNA labeling exhibits a pattern dependent on the microenvironment: in tumor-associated SCO tubules, it showed cytoplasmic localization, characteristic of an anti-apoptotic function, whereas isolated SCO tubules showed nuclear PCNA labeling, suggesting a potential role in DNA synthesis and repair. These findings highlight the interplay between iron homeostasis and cellular survival mechanisms, offering novel perspectives on its pathophysiology and implications for testicular cancer development. Full article

In older adults with reduced physical performance, an increase in the labile iron pool within skeletal muscle is observed. This accumulation is associated with an altered expression of mitochondrial quality control (MQC) markers and increased mitochondrial DNA damage, supporting the hypothesis that impaired MQC contributes to muscle dysfunction during aging. The autophagy–lysosome system plays a critical role in MQC by tagging and engulfing proteins and organelles for degradation in lysosomes. The endolysosomal system is also instrumental in transferrin recycling, which, in turn, regulates cellular iron uptake. In the neuromuscular system, the autophagy–lysosome system supports the structural integrity of neuromuscular junctions, and its dysfunction contributes to muscle atrophy. While MQC was thought to protect against iron-induced cell death, the discovery of ferroptosis, a form of iron-dependent cell death, has highlighted a complex interplay between MQC and iron-inflicted damage. Ferritinophagy, the autophagic degradation of ferritin, if overactivated, can induce ferroptosis. Alternatively, aging may impair ferritinophagy, leading to ferritin accumulation and the release of toxic labile iron under stress, exacerbating oxidative damage and cellular senescence. Physical activity supports muscle health also by preserving mitochondrial quantity and quality and enhancing bioenergetics. However, therapeutic strategies for preventing or reversing physical function decline in aging are still lacking due to the insufficient understanding of the underlying mechanisms. Unveiling how disruptions in iron homeostasis impact muscle quality in older adults may allow for the development of therapeutic strategies targeting iron handling to alleviate age-associated muscle decline. Full article

Background/Objectives: Magnetic hyperthermia (MH) has emerged as a promising alternative to conventional cancer treatments, offering targeted tumor destruction with minimal damage to healthy tissues. In this study, we synthesized manganese-doped magnetic nanoflowers (Mn-NFs) using a polyol-mediated approach to enhance heating efficiency and biocompatibility for MH applications. Our objective was to evaluate their structural, magnetic, and in vitro hyperthermic properties to determine their potential for lung cancer therapy. Methods: Mn-NFs, with the general formula MnxFe₃-xO₄ (x = 0, 0.3, 0.5, 0.7), were synthesized via a one-step polyol method and characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), and vibrating sample magnetometry (VSM). Their heating efficiency was assessed through specific absorption rate (SAR) measurements in aqueous and solid environments under an alternating magnetic field (AMF). Cytocompatibility was evaluated using the Alamar Blue assay on A549 lung carcinoma cells. Cellular uptake was quantified via a colorimetric iron determination method, while in vitro MH efficacy was tested by subjecting Mn-NF-loaded A549 cells to AMF exposure at different field strengths and nanoparticle concentrations. Results: Mn-NFs exhibited a flower-like morphology with enhanced magnetic properties, achieving high SAR values, particularly in immobilized conditions. Cytotoxicity assays confirmed high biocompatibility at relevant doses, with Mn-NFs of x = 0.3 showing optimal cellular uptake. MH studies demonstrated significant cancer cell death at AMF intensities of around 30 kA/m, with increased effectiveness following static magnetic field pre-alignment. Conclusions: The results highlight Mn-NFs, particularly those with a Mn content of x = 0.3, as promising candidates for MH-based lung cancer therapy, combining high heating efficiency, biocompatibility, and effective intracellular uptake. Further studies are needed to validate their therapeutic potential in vivo. Full article

Hypoxia, a phenomenon that occurs when the oxygen level in tissues is lower than average, is commonly observed in human solid tumors. For oncological treatment, the hypoxic environment often results in radioresistance and chemoresistance. In this study, a new multifunctional oxygen carrier, carboxymethyl hexanoyl chitosan (CHC) nanodroplets decorated with perfluorohexane (PFH) and superparamagnetic iron oxide (SPIO) nanodroplets (SPIO@PFH-CHC), was developed and investigated. PFH-based oxygen carriers can augment oxygenation within tumor tissues, thereby mitigating radioresistance. Concurrently, oxygenation can cause deoxyribonucleic acid (DNA) damage via oxygen fixation and consequently suppress cancer cell proliferation. Moreover, these pH-sensitive nanodroplets allow higher cellular uptake with minimal cytotoxicity. Two distinctive mechanisms of SPIO@PFH-CHC nanodroplets were found in this study. The SPIO nanoparticles of the SPIO@PFH-CHC nanodroplets can generate hydroxyl radicals (HO^•) and other reactive oxygen species (ROS), which is vital to chemodynamic therapy (CDT) via the Fenton reaction. Meanwhile, the higher X-ray absorption among these nanodroplets leads to a local energy surge and causes more extensive deoxyribonucleic acid (DNA) damage via oxygen fixation. This study demonstrates that low cytotoxic SPIO@PFH-CHC nanodroplets can be an efficient radiosensitizer for radiation therapy. Full article

Chronic diseases, including cardiovascular and neurodegenerative diseases and cancer, are significant global health challenges. Oxidative stress, characterized by an imbalance between reactive oxygen species (ROS) production and antioxidant defenses, is a critical factor in the progression of these pathologies. Lactoferrin (Lf), a multifunctional iron-binding glycoprotein, has emerged as a promising therapeutic agent due to its potent antioxidant, anti-inflammatory, and iron-regulating properties. Lf plays a pivotal role in iron homeostasis by chelating iron, modulating its cellular uptake, and reducing ROS production, thereby mitigating oxidative stress-related tissue damage. Lf also demonstrates neuroprotective potential in diseases like Parkinson’s and Alzheimer’s, where it alleviates oxidative damage, regulates iron metabolism, and enhances antioxidant defenses. Furthermore, its ability to enhance endogenous antioxidant mechanisms, such as superoxide dismutase and glutathione peroxidase, underscores its systemic protective effects. Lf’s anti-inflammatory and antimicrobial activities also contribute to its broad-spectrum protective role in chronic diseases. This review consolidates evidence of Lf’s mechanisms in mitigating oxidative stress and highlights its therapeutic potential as a versatile molecule for preventing and managing chronic conditions linked to oxidative damage. Full article

In recent years, research has gradually uncovered the mechanisms of animal adaptation to hypoxic conditions in different altitude environments, particularly at the genomic level. However, past genomic studies on high-altitude adaptation have often not delved deeply into the differences between varying altitude levels. This study conducted whole-genome sequencing on 60 Tibetan sheep (Medium Altitude Group (MA): 20 Tao sheep (TS) at 2887 m, High Altitude Group (HA): 20 OuLa sheep (OL) at 3501 m, and Ultra-High Altitude Group (UA): 20 AWang sheep (AW) at 4643 m) from different regions of the Tibetan Plateau in China to assess their responses under varying conditions. Population genetic structure analysis revealed that the three groups are genetically independent, but the TS and OL groups have experienced gene flow with other northern Chinese sheep due to geographical factors. Selection signal analysis identified FGF10, MMP14, SLC25A51, NDUFB8, ALAS1, PRMT1, PRMT5, and HIF1AN as genes associated with ultra-high-altitude hypoxia adaptation, while HMOX2, SEMA4G, SLC16A2, SLC22A17, and BCL2L2 were linked to high-altitude hypoxia adaptation. Functional analysis showed that ultra-high-altitude adaptation genes tend to influence physiological mechanisms directly affecting oxygen uptake, such as lung development, angiogenesis, and red blood cell formation. In contrast, high-altitude adaptation genes are more inclined to regulate mitochondrial DNA replication, iron homeostasis, and calcium signaling pathways to maintain cellular function. Additionally, the functions of shared genes further support the adaptive capacity of Tibetan sheep across a broad geographic range, indicating that these genes offer significant selective advantages in coping with oxygen scarcity. In summary, this study not only reveals the genetic basis of Tibetan sheep adaptation to different altitudinal conditions but also highlights the differences in gene regulation between ultra-high- and high-altitude adaptations. These findings offer new insights into the adaptive evolution of animals in extreme environments and provide a reference for exploring adaptation mechanisms in other species under hypoxic conditions. Full article