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Molecular Imaging and Biology Dec 2023Site-specific approaches to bioconjugation produce well-defined and homogeneous immunoconjugates with potential for superior in vivo behavior compared to analogs...
PURPOSE
Site-specific approaches to bioconjugation produce well-defined and homogeneous immunoconjugates with potential for superior in vivo behavior compared to analogs synthesized using traditional, stochastic methods. The possibility of incorporating photoaffinity chemistry into a site-specific bioconjugation strategy is particularly enticing, as it could simplify and accelerate the preparation of homogeneous immunoconjugates for the clinic. In this investigation, we report the synthesis, in vitro characterization, and in vivo evaluation of a site-specifically modified, Zr-labeled radioimmunoconjugate created via the reaction between an mAb and an Fc-binding protein bearing a photoactivatable 4-benzoylphenylalanine residue.
PROCEDURES
A variant of the Fc-binding Z domain of protein A containing a photoactivatable, 4-benzoylphenylalanine residue - Z(35BPA) - was modified with desferrioxamine (DFO), combined with the A33 antigen-targeting mAb huA33, and irradiated with UV light. The resulting immunoconjugate - DFO-huA33 - was purified and characterized via SDS-PAGE, MALDI-ToF mass spectrometry, surface plasmon resonance, and flow cytometry. The radiolabeling of DFO-huA33 was optimized to produce [Zr]Zr-DFO-huA33, and the immunoreactivity of the radioimmunoconjugate was determined with SW1222 human colorectal cancer cells. Finally, the in vivo performance of [Zr]Zr-DFO-huA33 in mice bearing subcutaneous SW1222 xenografts was interrogated via PET imaging and biodistribution experiments and compared to that of a stochastically labeled control radioimmunoconjugate, [Zr]Zr-DFO-huA33.
RESULTS
HuA33 was site-specifically modified with Z(35BPA)-DFO, producing an immunoconjugate with on average 1 DFO/mAb, high in vitro stability, and high affinity for its target. [Zr]Zr-DFO-huA33 was synthesized in 95% radiochemical yield and exhibited a specific activity of 2 mCi/mg and an immunoreactive fraction of ~ 0.85. PET imaging and biodistribution experiments revealed that high concentrations of the radioimmunoconjugate accumulated in tumor tissue (i.e., ~ 40%ID/g at 120 h p.i.) but also that the Z(35BPA)-bearing immunoPET probe produced higher uptake in the liver, spleen, and kidneys than its stochastically modified cousin, [Zr]Zr-DFO-huA33.
CONCLUSIONS
Photoaffinity chemistry and an Fc-binding variant of the Z domain were successfully leveraged to create a novel site-specific strategy for the synthesis of radioimmunoconjugates. The probe synthesized using this method - DFO-huA33 - was well-defined and homogeneous, and the resulting radioimmunoconjugate ([Zr]Zr-DFO-huA33) boasted high specific activity, stability, and immunoreactivity. While the site-specifically modified radioimmunoconjugate produced high activity concentrations in tumor tissue, it also yielded higher uptake in healthy organs than a stochastically modified analog, suggesting that optimization of this system is necessary prior to clinical translation.
Topics: Humans; Animals; Mice; Immunoconjugates; Tissue Distribution; Positron-Emission Tomography; Neoplasms; Zirconium; Cell Line, Tumor; Deferoxamine
PubMed: 37052759
DOI: 10.1007/s11307-023-01818-5 -
Pharmacological Research Jun 2024Disturbances in copper (Cu) homeostasis have been observed in diabetes and associated complications. Cu is an essential micronutrient that plays important roles in... (Review)
Review
Disturbances in copper (Cu) homeostasis have been observed in diabetes and associated complications. Cu is an essential micronutrient that plays important roles in various fundamental biological processes. For example, diabetic cardiomyopathy is associated with elevated levels of Cu in the serum and tissues. Therefore, targeting Cu may be a novel treatment strategy for diabetic complications. This review provides an overview of physiological Cu metabolism and homeostasis, followed by a discussion of Cu metabolism disorders observed during the occurrence and progression of diabetic complications. Finally, we discuss the recent therapeutic advances in the use of Cu coordination complexes as treatments for diabetic complications and their potential mechanisms of action. This review contributes to a complete understanding of the role of Cu in diabetic complications and demonstrates the broad application prospects of Cu-coordinated compounds as potential therapeutic agents.
PubMed: 38876443
DOI: 10.1016/j.phrs.2024.107264 -
Biology Mar 2024Ferroptosis, a regulated form of cell death characterized by iron-dependent lipid peroxide accumulation, plays a pivotal role in various pathological conditions,...
Ferroptosis, a regulated form of cell death characterized by iron-dependent lipid peroxide accumulation, plays a pivotal role in various pathological conditions, including neurodegenerative diseases. While reasonable evidence for ferroptosis exists, e.g., in Parkinson's disease or Alzheimer's disease, there are only a few reports on amyotrophic lateral sclerosis (ALS), a fast progressive and incurable neurodegenerative disease characterized by progressive motor neuron degeneration. Interestingly, initial studies have suggested that ferroptosis might be significantly involved in ALS. Key features of ferroptosis include oxidative stress, glutathione depletion, and alterations in mitochondrial morphology and function, mediated by proteins such as GPX4, xCT, ACSL4 FSP1, Nrf2, and TfR1. Induction of ferroptosis involves small molecule compounds like erastin and RSL3, which disrupt system Xc and GPX4 activity, respectively, resulting in lipid peroxidation and cellular demise. Mutations in fused in sarcoma () are associated with familial ALS. Pathophysiological hallmarks of FUS-ALS involve mitochondrial dysfunction and oxidative damage, implicating ferroptosis as a putative cell-death pathway in motor neuron demise. However, a mechanistic understanding of ferroptosis in ALS, particularly FUS-ALS, remains limited. Here, we investigated the vulnerability to ferroptosis in FUS-ALS cell models, revealing mitochondrial disturbances and increased susceptibility to ferroptosis in cells harboring ALS-causing FUS mutations. This was accompanied by an altered expression of ferroptosis-associated proteins, particularly by a reduction in xCT expression, leading to cellular imbalance in the redox system and increased lipid peroxidation. Iron chelation with deferoxamine, as well as inhibition of the mitochondrial calcium uniporter (MCU), significantly alleviated ferroptotic cell death and lipid peroxidation. These findings suggest a link between ferroptosis and FUS-ALS, offering potential new therapeutic targets.
PubMed: 38666827
DOI: 10.3390/biology13040215 -
Theranostics 2024Pulmonary fibrosis is a chronic progressive lung disease with limited therapeutic options. We previously revealed that there is iron deposition in alveolar epithelial...
Pulmonary fibrosis is a chronic progressive lung disease with limited therapeutic options. We previously revealed that there is iron deposition in alveolar epithelial type II cell (AECII) in pulmonary fibrosis, which can be prevented by the iron chelator deferoxamine. However, iron in the cytoplasm and the mitochondria has two relatively independent roles and regulatory systems. In this study, we aimed to investigate the role of mitochondrial iron deposition in AECII injury and pulmonary fibrosis, and to find potential therapeutic strategies. BLM-treated mice, MLE-12 cells, and primary AECII were employed to establish the mouse pulmonary fibrosis model and epithelial cells injury model, respectively. Mitochondrial transplantation, siRNA and plasmid transfection, western blotting (WB), quantitative real-time polymerase chain reaction (RT-qPCR), polymerase chain reaction (PCR), immunofluorescence, immunoprecipitation (IP), MitoSOX staining, JC-1 staining, oxygen consumption rate (OCR) measurement, and Cell Counting Kit-8 (CCK8) assay were utilized to elucidate the role of mitochondrial iron deposition in cell and lung fibrosis and determine its mechanism. This study showed that prominent mitochondrial iron deposition occurs within AECII in bleomycin (BLM)-induced pulmonary fibrosis mouse model and in BLM-treated MLE-12 epithelial cells. Further, the study revealed that healthy mitochondria rescue BLM-damaged AECII mitochondrial iron deposition and cell damage loss. Mitoferrin-2 (MFRN2) is the main transporter that regulates mitochondrial iron metabolism by transferring cytosolic iron into mitochondria, which is upregulated in BLM-treated MLE-12 epithelial cells. Direct overexpression of MFRN2 causes mitochondrial iron deposition and cell damage. In this study, decreased ubiquitination of the ubiquitin ligase F-box/LRR-repeat protein 5 (FBXL5) degraded iron-reactive element-binding protein 2 (IREB2) and promoted MFRN2 expression as well as mitochondrial iron deposition in damaged AECII. Activation of the prostaglandin E2 receptor EP4 subtype (EP4) receptor signaling pathway counteracted mitochondrial iron deposition by downregulating IREB2-MFRN2 signaling through upregulation of FBXL5. This intervention not only reduced mitochondrial iron content but also preserved mitochondrial function and protected against AECII damage after BLM treatment. Our findings highlight the unexplored roles, mechanisms, and regulatory approaches of abnormal mitochondrial iron metabolism of AECII in pulmonary fibrosis. Therefore, this study deepens the understanding of the mechanisms underlying pulmonary fibrosis and offers a promising strategy for developing effective therapeutic interventions using the EP4 receptor activator.
Topics: Animals; Bleomycin; Mitochondria; Pulmonary Fibrosis; Mice; Iron; Alveolar Epithelial Cells; Disease Models, Animal; Mice, Inbred C57BL; Cell Line; Male
PubMed: 38773980
DOI: 10.7150/thno.94072 -
Environmental Pollution (Barking, Essex... Oct 2023Environmental methylmercury (MeHg) exposure has gained global attention owing to its serious health hazards, especially neurotoxicity. Ferroptosis is a novel form of...
Environmental methylmercury (MeHg) exposure has gained global attention owing to its serious health hazards, especially neurotoxicity. Ferroptosis is a novel form of programmed cell death characterized by lipid peroxidation and iron overload. However, the occurrence of ferroptosis and its underlying mechanisms have not been fully elucidated in the methylmercury-induced neurotoxicity and the role of Nrf2 in MeHg-induced ferroptosis remains unexplored. In this study, we verified that MeHg decreased cell viability in a dose- and time-dependent manner in the Rat Brain Astrocytes cells (CTX cells). MeHg (3.5 μmol/L) exposure induced CTX cells to undergo ferroptosis, as evidenced by glutathione (GSH) depletion, lipid peroxidation, and iron overload, which was significantly rescued by the ferroptosis-specific inhibitors Ferrostatin-1 and Deferoxamine. MeHg directly disrupted the process of GSH metabolism by downregulating of SLC7A11 and GPX4 and interfered with intracellular iron homeostasis through inhibition of iron storage and export. Simultaneously, the expression of Nrf2 was upregulated by MeHg in CTX cells. Hence, the inhibition of Nrf2 activity further downregulated the levels of GPX4, SLC7A11, FTH1, and SLC40A1, which aggravated MeHg-induced ferroptosis to a greater extent. Overall, our findings provided evidence that ferroptosis played a critical role in MeHg-induced neurotoxicity, and suppressing Nrf2 activity further exacerbated MeHg-induced ferroptosis in CTX cells.
Topics: Rats; Animals; Ferroptosis; Methylmercury Compounds; NF-E2-Related Factor 2; Iron; Iron Overload; Homeostasis; Glutathione
PubMed: 37517642
DOI: 10.1016/j.envpol.2023.122278 -
ACS Omega Aug 2023Deferoxamine (DFO) is an effective FDA-approved iron chelator; however, its use is considerably limited by off-target toxicities and an extremely cumbersome dose regimen...
Deferoxamine (DFO) is an effective FDA-approved iron chelator; however, its use is considerably limited by off-target toxicities and an extremely cumbersome dose regimen involving daily infusions. The recent development of a deferoxamine-based nanochelator (DFO-NP) with selective renal excretion has shown promise in ameliorating iron overload and associated physiological complications in rodent models with a substantially improved safety profile. While the dose- and administration route-dependent pharmacokinetics (PK) of DFO-NPs have been recently characterized, the optimized PK model was not validated, and the prior studies did not directly address the clinical translatability of DFO-NPs into humans. In the present work, these gaps were addressed by applying allometric scaling of DFO-NP PK in rats to predict those in mice and humans. First, this approach predicted serum concentration-time profiles of DFO-NPs, which were similar to those experimentally measured in mice, validating the nonlinear disposition and absorption models for DFO-NPs across the species. Subsequently, we explored the utility of allometric scaling by predicting the PK profile of DFO-NPs in humans under clinically relevant dosing schemes. These in silico efforts demonstrated that the novel nanochelator is expected to improve the PK of DFO when compared to standard infusion regimens of native DFO. Moreover, reasonable formulation strategies were identified and discussed for both early clinical development and more sophisticated formulation development.
PubMed: 37546686
DOI: 10.1021/acsomega.3c02570 -
Hydrogen sulfide alleviates beryllium sulfate-induced ferroptosis and ferritinophagy in 16HBE cells.Journal of Applied Toxicology : JAT Aug 2023Beryllium sulfate (BeSO ) can result to lung injuries, such as leading to lipid peroxidation and autophagy, and the treatment of beryllium disease has not been well...
Beryllium sulfate (BeSO ) can result to lung injuries, such as leading to lipid peroxidation and autophagy, and the treatment of beryllium disease has not been well improved. Ferroptosis is a regulated cell death process driven by iron-dependent and lipid peroxidation, while ferritinophagy is a process mediated by nuclear receptor coactivator 4 (NCOA4), combined with ferritin heavy chain 1 (FTH1) degradation and release Fe , which regulated intracellular iron metabolism and ferroptosis. Hydrogen sulfide (H S) has the effects of antioxidant, antiautophagy, and antiferroptosis. This study aimed to investigate the effect of H S on BeSO -induced ferroptosis and ferritinophagy in 16HBE cells and the underlying mechanism. In this study, BeSO -induced 16HBE cell injury model was established based on cellular level and pretreated with deferoxamine (DFO, a ferroptosis inhibitor), sodium hydrosulfide (NaHS, a H S donor), or NCOA4 siRNA and, subsequently, performed to detect the levels of lipid peroxidation and Fe and the biomarkers of ferroptosis and ferritinophagy. More importantly, our research found that DFO, NaHS, or NCOA4 siRNA alleviated BeSO -induced ferroptosis and ferritinophagy by decreasing the accumulation of Fe and lipid peroxides. Furthermore, the relationship between ferroptosis, ferritinophagy, H S, and beryllium disease is not well defined; therefore, our research is innovative. Overall, our results provided a new theoretical basis for the prevention and treatment of beryllium disease and suggested that the application of H S, blocking ferroptosis, and ferritinophagy may be a potential therapeutic direction for the prevention and treatment of beryllium disease.
Topics: Humans; Hydrogen Sulfide; Berylliosis; Ferroptosis; Autophagy; Iron; RNA, Small Interfering; Transcription Factors
PubMed: 36843388
DOI: 10.1002/jat.4453 -
Molecular and Cellular Biochemistry May 2024Iron accumulation, which is controlled by transferrin receptor 1 (TfR1), modulates hypoxia-inducible factor-1α (HIF-1α) activation and angiogenesis of hypoxic...
Iron accumulation, which is controlled by transferrin receptor 1 (TfR1), modulates hypoxia-inducible factor-1α (HIF-1α) activation and angiogenesis of hypoxic endothelial cells. The study examined the role of protein interacting with C-kinase 1 (PICK1), a scaffold protein containing PDZ domain, in regulating glycolysis and angiogenesis of hypoxic vascular endothelial cells through its potential effect on TfR1, which features a supersecondary structure that interacts with the PDZ domain. Iron chelator deferoxamine and TfR1 siRNA were employed to assess the impact of iron accumulation on angiogenesis, while the effects of PICK1 siRNA and overexpressing lentivirus on TfR1-mediated iron accumulation were also investigated in hypoxic human umbilical vein vascular endothelial cells (HUVECs). The study found that 72-h hypoxia impaired the proliferation, migration, and tube formation of HUVECs, and reduced the upregulation of vascular endothelial growth factor, HIF-1α, 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3, and PICK1, while increasing the expression of TfR1 as compared to 24-h hypoxia. Administration of deferoxamine or TfR1 siRNA reversed these effects and led to increased glycolysis, ATP content, and phosphofructokinase activity, along with increased PICK1 expression. PICK1 overexpression improved glycolysis, enhanced angiogenic capacity, and attenuated TfR1 protein upregulation in hypoxic HUVECs, with higher expression of angiogenic markers, which could be significantly reversed by the PDZ domain inhibitor. PICK1 knockdown exerted opposite effects. The study concluded that PICK1 modulated intracellular iron homeostasis, thereby promoting glycolysis and angiogenesis of HUVECs in response to prolonged hypoxia, at least in part, by regulating TfR1 expression.
Topics: Humans; Glycolysis; Human Umbilical Vein Endothelial Cells; Iron; Carrier Proteins; Receptors, Transferrin; Homeostasis; Nuclear Proteins; Cell Hypoxia; Neovascularization, Physiologic; Antigens, CD; Hypoxia-Inducible Factor 1, alpha Subunit; Angiogenesis
PubMed: 37368155
DOI: 10.1007/s11010-023-04795-z -
Journal of Agricultural and Food... Nov 2023Sodium sulfite is a widely used preservative in the food industry. Ferroptosis has been a newly discovered form of iron-dependent oxidative cell death in recent years....
Sodium sulfite is a widely used preservative in the food industry. Ferroptosis has been a newly discovered form of iron-dependent oxidative cell death in recent years. However, the potential connection between sodium sulfite and ferroptosis has not been explored. In our study, we observed the abnormal expression of ferroptosis marker protein , suggesting that sodium sulfite caused ferroptosis . Next, our study revealed that sodium sulfite caused the overproduction of mitochondrial reactive oxygen species (mtROS) in the AML-12 cells. It is well established that reactive oxygen species (ROS) can induce lysosomal membrane permeabilization. After lysosomal membrane permeabilization occurs, the outflow of Fe in lysosomes triggers the Fenton reaction and subsequently results in the increase of intracellular ROS level, which is closely related to ferroptosis. As speculated, acridine orange (AO) staining and LysoTracker red staining showed that sodium sulfite-induced lysosomal membrane permeabilization could be alleviated by mtROS scavenger TEMPO. In addition, TEMPO, lysosomal stabilizer mannose, and lysosomal iron chelator deferoxamine (DFO) inhibited sodium sulfite-induced ferroptosis. Overall, the results showed that sodium sulfite induced lysosomal iron efflux through the mtROS-lysosomal membrane permeabilization pathway and eventually led to ferroptosis. Our study might provide a new mechanism for the hepatotoxicity of sodium sulfite and a theoretical basis for the risk assessment of sodium sulfite as a food additive.
Topics: Ferroptosis; Reactive Oxygen Species; Iron; Hepatocytes; Lysosomes
PubMed: 37871339
DOI: 10.1021/acs.jafc.3c06085 -
Free Radical Research Feb 2024Ferroptosis is recognized as a new type of regulated cell death initiated by iron-dependent accumulation of lipid peroxidation. Recent studies have shown that the...
Ferroptosis is recognized as a new type of regulated cell death initiated by iron-dependent accumulation of lipid peroxidation. Recent studies have shown that the administration of ascorbic acid (AA) preferentially kills tumor cells by impairing iron metabolism and exerting pro-oxidant effects. Despite mounting evidence indicating the anticancer potential of AA, the underlying molecular mechanisms remain unknown. In this study, we demonstrated that AA decreased cell viability and Ki67 expression, along with its accumulation in the G/G phase in FaDu and SCC-154 cell lines. Furthermore, AA exposure induced morphological changes in mitochondria associated with ferroptosis. AA-induced ferroptosis is accompanied by depletion of glutathione (GSH) and increased levels of ferrous ions (Fe), reactive oxygen species (ROS), and malondialdehyde (MDA). However, these ferroptotic effects were ameliorated by deferoxamine and N-acetylcysteine. Network pharmacology results showed that signal transducer and activator of transcription 3 (STAT3) is a key target of AA against oropharyngeal cancer. AA markedly downregulates the relative mRNA expression of STAT3 and glutathione peroxidase 4 (GPX4). Immunoblotting indicated that the protein levels of p-STAT3, STAT3, and GPX4 in FaDu and SCC-154 cells decreased significantly in response to AA treatment. Mechanistically, a chromatin immunoprecipitation assay confirmed that AA exposure reduced STAT3 expression in the GPX4 promoter region. Additionally, AA-induced inhibition of cell growth and ferroptosis was suppressed by STAT3 and GPX4 overexpression, respectively. In summary, AA inhibited oropharyngeal cancer cell growth by regulating STAT3/GPX4-mediated ferroptosis, which may provide a novel theoretical basis for the clinical treatment of oropharyngeal cancer with AA.
Topics: Humans; Ascorbic Acid; Ferroptosis; STAT3 Transcription Factor; Reactive Oxygen Species; Oropharyngeal Neoplasms; Iron
PubMed: 38385781
DOI: 10.1080/10715762.2024.2320396