Search Results (121)

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

Feline parvovirus (FPV) causes feline panleukopenia, a highly contagious disease in cats, marked by severe leukopenia, biphasic fever, diarrhea, vomiting, and hemorrhagic enteritis. Recently, FPV infection in giant pandas has increased, causing diarrhea and ultimately fatal outcomes, thereby threatening their survival and reproduction. Here, we investigated the transmission of FPV in giant pandas and its interaction with cellular receptors using an FPV strain (pFPV-sc) isolated from giant panda feces. Recombinant feline transferrin receptor 1 (fTfR1) and the giant panda ortholog (gpTfR1) were expressed in non-susceptible HEK293T and HeLa cells, while viral infection levels were measured to determine the effect of gpTfR1 on pFPV-sc replication. The findings indicated that gpTfR1 overexpression in non-susceptible cells significantly enhanced pFPV-sc replication, particularly influencing the viral attachment and internalization stages. Our data further revealed early-stage colocalization between gpTfR1 expression and virus infection, suggesting that gpTfR1 facilitates early viral infection and replication. Taken together, our study provides the first evidence on the mechanism of FPV cross-species infection in giant pandas and elucidates the interaction between gpTfR1 and FPV, which establishes a theoretical basis for the development of preventive and therapeutic strategies, thereby safeguarding the health and survival of giant panda populations from FPV. Full article

Aging leads to ovarian degeneration in poultry, reducing egg production and quality. Ellagic acid (EA), a natural plant-derived compound, may help delay ovarian aging, though its precise mechanisms remain unclear. This study investigated the effects of EA on ovarian aging of low-yield laying chickens and explored its underlying mechanism. EA supplementation (100 and 500 mg/kg) significantly increased ovarian weight as well as the number and proportion of small yellow follicles in aging chickens. EA administration elevated serum antioxidant levels and upregulated the expression of glutathione peroxidase 4 (GPX4) expression to reduce oxidative stress. Importantly, EA treatment suppressed the mRNA and protein expression of ferroptosis markers transferrin receptor protein 1 (TFRC) and solute carrier family 7 member 11 (SLC7A11), increased Proliferating Cell Nuclear Antigen (PCNA) expression, and alleviated G1 phase arrest in granulosa cells (GCs), promoting cell proliferation, which improves egg quality and production. Furthermore, in vitro experiments demonstrated that EA treatment decreased reactive oxygen species production, improved mitochondrial function, inhibited ferroptosis, and attenuated GCs aging. In conclusion, this study reveals the critical role of ferroptosis in chicken ovarian aging and suggests that EA may provide a promising approach for delaying ovarian aging and enhancing productivity in low-yield poultry. 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

The mandibular condyle cartilage serves as a principal zone for mandible growth, and any dysplasia could contribute to skeletal mandibular hypoplasia (SMH). The aim of the study was to further explore how TFRC signaling regulates condylar cartilage development. In this study, TFRC, SLC39A14, chondrogenic markers and ferroptosis-related signals were detected in the condylar cartilage of postnatal mice and Tfrc cartilage conditional knockout (Tfrc-cKO) mice at different time points through immunofluorescence, immunohistochemical staining and qPCR assays. The overexpression and knockdown of TFRC in the ATDC5 cell line were used to investigate its role in a specific biological process. Co-immunoprecipitation was used to verify protein–protein interaction in vitro. Ferroptosis inhibitor Fer1, Ac-Met-OH and DFP were used for an in vitro rescue assay. The temporomandibular joint injection of DFP was used to rescue the cartilage phenotype in vivo. Our results verified that TFRC was crucial for condylar cartilage development. TFRC ablation led to condylar cartilage thickness and condyle length alterations and induced the ferroptosis of chondrocyte by upregulating SLC39A14. Mitochondrial p53 translocation was involved in the TFRC–SLC39A14 switch by SLC39A14 ubiquitination degradation. Fer1, Ac-Met-OH and DFP inhibited ferroptosis and restored chondrogenic differentiation in vivo. The temporomandibular joint injection of DFP could rescue the cartilage phenotype. In summary, this study reveals that TFRC influences postnatal condylar cartilage development through mitochondrial p53 translocation-mediated ferroptosis, which provides insights into the etiology, pathogenesis, and therapy of mandibular hypoplasia and even systemic articular cartilage dysplasia. Full article

Iron overload can lead to increased deposition of iron and cause organ damage in the liver, the pancreas, the heart and the synovium. Iron overload disorders are due to either genetic or acquired abnormalities such as excess transfusions or chronic liver diseases. The most common genetic disease of iron deposition is classic hemochromatosis (HH) type 1, which is caused by mutations of HFE. Other rare forms of HH include type 2A with mutations at the gene hemojuvelin or type 2B with mutations in HAMP that encodes hepcidin. HH type 3, is caused by mutations of the gene that encodes transferrin receptor 2. Mutations of SLC40A1 which encodes ferroportin cause either HH type 4A or HH type 4B. In the present review, an overview of iron metabolism including absorption by enterocytes and regulation of iron by macrophages, liver sinusoidal endothelial cells (LSECs) and hepatocyte production of hepcidin is presented. Hereditary Hemochromatosis and the current pathogenetic model are analyzed. Finally, a new hypothesis based on published data was suggested. The Kupffer cell is the primary defect in HFE hemochromatosis (and possibly in types 2 and 3), while the hepcidin-relative deficiency, which is the common underlying abnormality in the three types of HH, is a secondary consequence. Full article

Iron overload disease is characterized by the excessive accumulation of iron in the body. To better alleviate iron overload, there is an urgent need for safe and effective small molecule compounds. Rubiadin, the active ingredient derived from the Chinese herb Prismatomeris tetrandra, possesses notable anti-inflammatory and hepatoprotective properties. Nevertheless, its impact on iron metabolism remains largely unexplored. To determine the role of rubiadin on iron metabolism, Western blot analysis, real-time PCR analysis, and the measurement of serum iron were performed. Herein, we discovered that rubiadin significantly downregulated the expression of transferrin receptor 1, ferroportin 1, and ferritin light chain in ferric-ammonium-citrate-treated or -untreated HepG2 cells. Moreover, intraperitoneal administration of rubiadin remarkably decreased serum iron and duodenal iron content and upregulated expression of hepcidin mRNA in the livers of high-iron-fed mice. Mechanistically, bone morphogenetic protein 6 (BMP6) inhibitor LDN-193189 completely reversed the hepcidin upregulation and suppressor of mother against decapentaplegic 1/5/9 (SMAD1/5/9) phosphorylation induced by rubiadin. These results suggested that rubiadin increased hepcidin expression through the BMP6/SMAD1/5/9-signaling pathway. Collectively, our findings uncover a crucial mechanism through which rubiadin modulates iron metabolism and highlight it as a potential natural compound for alleviating iron-overload-related diseases. Full article

Transferrin Receptor 2 (TfR2) is a homolog of Transferrin Receptor 1 (TfR1), involved in regulating intra and extracellular iron levels. Altered iron pathways have been associated with cancer onset and progression; however, their role in canine tumors remains poorly explored. This study investigated TfR2 immunohistochemical expression in non-neoplastic canine testis for the first time and in the most common types of canine testicular tumors: intratubular seminomas (ITSEMs), diffuse seminomas (DSEMs), Leydig cell tumors (LCTs), and Sertoli cell tumors (SCTs). Immunohistochemical analysis revealed a differential pattern of TfR2 expression according to tumor type, with high expression observed in ITSEMs and DSEMs, occasional expression in LCTs, and absence in SCTs. These results suggest that TfR2 may play a relevant role in canine seminoma development. Furthermore, the specific expression of TfR2 in seminomas highlights its potential as a therapeutic target, where its role in iron regulation and possible compensatory mechanisms warrant further investigation. Full article

The Junín virus (JUNV) is one of the New World arenaviruses that cause severe hemorrhagic fever. Human transferrin receptor 1 (hTfR1) has been identified as the main receptor for JUNV for virus entry into host cells. To date, no treatment has been approved for JUNV. Herein, we investigated 12 anti-hTfR1 VHH (variable domain of the heavy chain of heavy-chain antibody) antibodies and confirmed their interaction with hTfR1. Most of them could bind to the hTfR1 apical domain, which is the glycoprotein 1 (GP1) binding domain of JUNV. Among them, 18N18 exhibited neutralizing activity against both the human immunodeficiency virus (HIV)-vectored lentiviral Junín pseudoviruses and the recombinant vesicular stomatitis virus (VSV)-vectored Junín pseudoviruses. We also verified that 18N18 blocked the interaction between hTfR1 and JUNV GP1. In addition, 18N18 could neutralize another New World arenavirus, the Machupo virus. Using AlphaFold 3-based simulation of 18N18–hTfR1 docking, we determined that 18N18’s binding epitope was located at the JUNV GP1 binding epitope. 18N18 represents a candidate for JUNV treatment and provides a potential approach that could be applied to New World arenaviruses. Full article

The Sprouty (SPRY) proteins are evolutionary conserved modulators of receptor tyrosine kinase (RTK) signaling. SPRY2 inhibits fibroblast growth factor (FGF) signaling, whereas it enhances epidermal growth factor (EGF) signaling through inhibition of EGF receptor (EGFR) endocytosis, ubiquitination, and degradation. In this study, we analyzed the effects of SPRY2 on endocytosis and degradation of FGF receptor 1 (FGFR1) using two human glioblastoma (GBM) cell lines with different endogenous SPRY2 levels. SPRY2 overexpression (SPRY2-OE) inhibited clathrin- and caveolae-mediated endocytosis of FGFR1, reduced the number of caveolin-1 vesicles and the uptake of transferrin. Furthermore, FGFR1 protein was decreased by SPRY2-OE, whereas EGFR protein was increased. SPRY2-OE enhanced FGFR1 degradation by increased c-casitas b-lineage lymphoma (c-CBL)-mediated ubiquitination, but it diminished binding of phospholipase Cγ1 (PLCγ1) to FGFR1. Consequently, SPRY2-OE inhibited FGF2-induced activation of PLCγ1, whereas it enhanced EGF-induced PLCγ1 activation. Despite the reduction of FGFR1 protein and the inhibition of FGF signaling, SPRY2-OE increased cell viability, and knockdown of SPRY2 enhanced the sensitivity to cisplatin. These results demonstrate that the inhibitory effect of SPRY2-OE on FGF signaling is at least in part due to the reduction in FGFR1 levels and the decreased binding of PLCγ1 to the receptor. Full article

In recent years, alongside research on mammalian-derived exosomes, there has been increasing interest in the physiological activities of plant-derived exosome-like nanoparticles (PDEN). The biocompatibility, minimal side effects, and diverse bioactive ingredients contained in PDEN make them valuable as potential therapeutic agents for an extensive range of diseases. In this study, we cost-effectively isolated exosome-like nanoparticles from green onion (Allium fistulosum) using polyethylene glycol and examined their biological activity in HT-22 cells exposed to glutamate. The isolated green onion-derived exosome-like nanoparticle (GDEN) had an average diameter of 167.4 nm and a zeta potential of −16.06 mV. GDEN effectively inhibited glutamate-induced Ca²⁺ influx and lipid peroxidation, thereby preventing ferroptotic cell death in HT-22 mouse hippocampal cells. Additionally, GDEN reduced the intracellular iron accumulation by modulating the expression of proteins associated with iron metabolism, including transferrin receptor 1, ferroportin 1, divalent metal transporter 1, and ferritin. Notably, GDEN upregulated the expression of glutathione peroxidase 4, a potent antioxidant protein involved in ferroptosis, along with an increase in glutathione synthesis. These findings indicate that GDENs have the potential to serve as bioactives from natural sources against glutamate-induced neuronal cell death, like ferroptosis. This study advances the investigation into the potential medical applications of GDEN and may provide a new approach for the utilization of these bioactive components against neuronal disorders. Full article

Iron is a key element in spermatogenesis; its metabolic pathway in the testis is strictly regulated. Alterations in iron metabolism are linked to various diseases, including cancer, and changes in iron metabolism-related proteins have been observed in multiple human, mouse and canine tumors. There is limited knowledge about iron metabolism in canine non-neoplastic and neoplastic testes. This study aimed to explore the immunohistochemical expression of molecules involved in iron uptake and storage [Transferrin Receptor 1 (TfR1), ferritin (FTH1), nuclear receptor coactivator 4 (NCOA4)] and PCNA in canine non-neoplastic and neoplastic testicular samples. Non-neoplastic testes showed moderate TfR1 expression in developing germ cells and Sertoli cells, high NCOA4 cytoplasmic immunostaining in the Sertoli cells and occasional cytoplasmic immunopositivity for FTH1 in the spermatogonia and Sertoli cells. In contrast, Leydig cell tumors (LCTs) and Diffuse Type Seminoma (DSEM) exhibited increased expression of TfR1, along with higher PCNA expression, suggesting a higher iron need for proliferation. Intratubular Type Seminoma (ITSEM) showed a higher FTH1 expression, indicating greater iron storage, while the increased NCOA4 expression in the LCTs and DSEM suggested ferritinophagy to release iron for proliferation. Sertoli cell tumors (SCTs) showed only NCOA4 expression. These preliminary findings highlight potential molecular targets for developing new anti-neoplastic treatments in canine testicular tumors. Full article

Prolonged exposure to hydroquinone (HQ), a metabolite of benzene, can cause severe haematologic disorders in humans. However, the mechanism is still unclear. In the present study, we investigated whether HQ can induce haematological diseases through ferroptosis, which is another form of cell death apart from apoptosis. The results showed that HQ inhibited the viability of Jurkat cells in a dose-dependent and time-dependent manner. The half inhibitory concentrations (IC50s) of HQ-treated Jurkat cells for 12 h, 24 h and 48 h were 107.16 μmol/L, 33.29 μmol/L, and 14.78 μmol/L. The exposure of Jurkat cells to HQ increased intracellular ${\mathrm{Fe}}^{2+}$, malondialdehyde (MDA) and lipid reactive oxygen species (ROS) levels and down-regulated glutathione (GSH) levels. We used erastin-treated cells as a positive control and cells treated with HQ combined with deferoxamine mesylate (DFO) and ferrostain-1 (Fer-1)-treated cells as the negative controls. DFO and Fer-1 partially restored the degradation of cell viability and GSH content and the accumulation of ${\mathrm{Fe}}^{2+}$, MDA and lipid ROS caused by HQ. In addition, we found that cellular mitochondria in the HQ-treated group showed a decrease in volume, an increase in the density of the bilayer membrane and a decrease or disappearance of mitochondrial cristae. Changes in the erastin-treated group were similar to those in the HQ-treated group. We inferred that HQ induces ferroptosis in Jurkat cells. Subsequently, we found that HQ up-regulated the levels of transferrin receptor 1 (TFRC) mRNA and protein expression and down-regulated FTH1, SLC7A11 and synthetic substrate of antioxidant enzyme 4 (GPX4) mRNA levels and protein expression levels. However, the exposure of Jurkat cells to HQ with DFO and Fer-1 alleviated these changes. Notably, the activation of TFRC and the inhibition of FTH1 and System ${{\mathrm{X}}_c}^{-}$ (cystine–glutamate reverse transporter protein) /GPX4 were associated with HQ-induced ferroptosis. These results provide novel insights into how HQ exacerbates haematopoietic cytotoxicity and provide potential targets for the prevention of HQ-induced diseases. Full article