The pathogenic fungus Aspergillus fumigatus utilizes a cyclic ferrioxamine E (FOXE) siderophore to acquire iron from the host. Biomimetic FOXE analogues were labeled with gallium-68 for molecular imaging with PET. [68Ga]Ga(III)-FOXE analogues were internalized in A. fumigatus cells via Sit1. Uptake of [68Ga]Ga(III)-FOX 2-5, the most structurally alike analogue to FOXE, was high by both A. fumigatus and bacterial Staphylococcus aureus. However, altering the ring size provoked species-specific uptake between these two microbes: ring size shortening by one methylene unit (FOX 2-4) increased uptake by A. fumigatus compared to that by S. aureus, whereas lengthening the ring (FOX 2-6 and 3-5) had the opposite effect. These results were consistent both in vitro and in vivo, including PET imaging in infection models. Overall, this study provided valuable structural insights into the specificity of siderophore uptake and, for the first time, opened up ways for selective targeting and imaging of microbial pathogens by siderophore derivatization.
- MeSH
- Aspergillus fumigatus * metabolism chemistry MeSH
- Aspergillosis * diagnostic imaging microbiology MeSH
- Biomimetic Materials chemistry metabolism MeSH
- Peptides, Cyclic MeSH
- Deferoxamine chemistry MeSH
- Species Specificity MeSH
- Mice MeSH
- Positron-Emission Tomography * methods MeSH
- Gallium Radioisotopes * chemistry MeSH
- Siderophores * chemistry metabolism MeSH
- Staphylococcus aureus * metabolism MeSH
- Ferric Compounds chemistry MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Iron, as an essential micronutrient, plays a crucial role in host-pathogen interactions. In order to limit the growth of the pathogen, a common strategy of innate immunity includes withdrawing available iron to interfere with the cellular processes of the microorganism. Against that, unicellular parasites have developed powerful strategies to scavenge iron, despite the effort of the host. Iron-sequestering compounds, such as the approved and potent chelator deferoxamine (DFO), are considered a viable option for therapeutic intervention. Since iron is heavily utilized in the mitochondrion, targeting iron chelators in this organelle could constitute an effective therapeutic strategy. This work presents mitochondrially targeted DFO, mitoDFO, as a candidate against a range of unicellular parasites with promising in vitro efficiency. Intracellular Leishmania infection can be cleared by this compound, and experimentation with Trypanosoma brucei 427 elucidates its possible mode of action. The compound not only affects iron homeostasis but also alters the physiochemical properties of the inner mitochondrial membrane, resulting in a loss of function. Furthermore, investigating the virulence factors of pathogenic yeasts confirms that mitoDFO is a viable candidate for therapeutic intervention against a wide spectrum of microbe-associated diseases.
Labile redox-active iron ions have been implicated in various neurodegenerative disorders, including the Parkinson's disease (PD). Iron chelation has been successfully used in clinical practice to manage iron overload in diseases such as thalassemia major; however, the use of conventional iron chelators in pathological states without systemic iron overload remains at the preclinical investigative level and is complicated by the risk of adverse outcomes due to systemic iron depletion. In this study, we examined three clinically-used chelators, namely, desferrioxamine, deferiprone and deferasirox and compared them with experimental agent salicylaldehyde isonicotinoyl hydrazone (SIH) and its boronate-masked prochelator BSIH for protection of differentiated PC12 cells against the toxicity of catecholamines 6-hydroxydopamine and dopamine and their oxidation products. All the assayed chelating agents were able to significantly reduce the catecholamine toxicity in a dose-dependent manner. Whereas hydrophilic chelator desferrioxamine exerted protection only at high and clinically unachievable concentrations, deferiprone and deferasirox significantly reduced the catecholamine neurotoxicity at concentrations that are within their plasma levels following standard dosage. SIH was the most effective iron chelator to protect the cells with the lowest own toxicity of all the assayed conventional chelators. This favorable feature was even more pronounced in prochelator BSIH that does not chelate iron unless its protective group is cleaved in disease-specific oxidative stress conditions. Hence, this study demonstrated that while iron chelation may have general neuroprotective potential against catecholamine auto-oxidation and toxicity, SIH and BSIH represent promising lead molecules and warrant further studies in more complex animal models.
- MeSH
- PC12 Cells MeSH
- Iron Chelating Agents * pharmacology MeSH
- Deferasirox pharmacology MeSH
- Deferiprone pharmacology MeSH
- Deferoxamine pharmacology MeSH
- Dopamine pharmacology MeSH
- Catecholamines pharmacology MeSH
- Rats MeSH
- Oxidative Stress MeSH
- Oxidopamine pharmacology MeSH
- Iron Overload * MeSH
- Iron pharmacology MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
PURPOSE: With the increase of especially hospital-acquired infections, timely and accurate diagnosis of bacterial infections is crucial for effective patient care. Molecular imaging has the potential for specific and sensitive detection of infections. Siderophores are iron-specific chelators recognized by specific bacterial transporters, representing one of few fundamental differences between bacterial and mammalian cells. Replacing iron by gallium-68 without loss of bioactivity is possible allowing molecular imaging by positron emission tomography (PET). Here, we report on the preclinical evaluation of the clinically used siderophore, desferrioxamine-B (Desferal®, DFO-B), radiolabelled with 68Ga for imaging of bacterial infections. METHODS: In vitro characterization of [68Ga]Ga-DFO-B included partition coefficient, protein binding and stability determination. Specific uptake of [68Ga]Ga-DFO-B was tested in vitro in different microbial cultures. In vivo biodistribution was studied in healthy mice and dosimetric estimation for human setting performed. PET/CT imaging was carried out in animal infection models, representing the most common pathogens. RESULTS: DFO-B was labelled with 68Ga with high radiochemical purity and displayed hydrophilic properties, low protein binding and high stability in human serum and PBS. The high in vitro uptake of [68Ga]Ga-DFO-B in selected strains of Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus agalactiae could be blocked with an excess of iron-DFO-B. [68Ga]Ga-DFO-B showed rapid renal excretion and minimal retention in blood and other organs in healthy mice. Estimated human absorbed dose was 0.02 mSv/MBq. PET/CT images of animal infection models displayed high and specific accumulation of [68Ga]Ga-DFO-B in both P. aeruginosa and S. aureus infections with excellent image contrast. No uptake was found in sterile inflammation, heat-inactivated P. aeruginosa or S. aureus and Escherichia coli lacking DFO-B transporters. CONCLUSION: DFO-B can be easily radiolabelled with 68Ga and displayed suitable in vitro characteristics and excellent pharmacokinetics in mice. The high and specific uptake of [68Ga]Ga-DFO-B by P. aeruginosa and S. aureus was confirmed both in vitro and in vivo, proving the potential of [68Ga]Ga-DFO-B for specific imaging of bacterial infections. As DFO-B is used in clinic for many years and the estimated radiation dose is lower than for other 68Ga-labelled radiopharmaceuticals, we believe that [68Ga]Ga-DFO-B has a great potential for clinical translation.
- MeSH
- Deferoxamine * MeSH
- Mice MeSH
- Positron Emission Tomography Computed Tomography MeSH
- Tomography, X-Ray Computed MeSH
- Positron-Emission Tomography MeSH
- Gallium Radioisotopes * MeSH
- Staphylococcus aureus MeSH
- Tissue Distribution MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Angiogenesis has a pivotal role in tumor growth and the metastatic process. Molecular imaging was shown to be useful for imaging of tumor-induced angiogenesis. A great variety of radiolabeled peptides have been developed to target αvβ3 integrin, a target structure involved in the tumor-induced angiogenic process. The presented study aimed to synthesize deferoxamine (DFO)-based c(RGD) peptide conjugate for radiolabeling with gallium-68 and perform its basic preclinical characterization including testing of its tumor-imaging potential. DFO-c(RGDyK) was labeled with gallium-68 with high radiochemical purity. In vitro characterization including stability, partition coefficient, protein binding determination, tumor cell uptake assays, and ex vivo biodistribution as well as PET/CT imaging was performed. [68Ga]Ga-DFO-c(RGDyK) showed hydrophilic properties, high stability in PBS and human serum, and specific uptake in U-87 MG and M21 tumor cell lines in vitro and in vivo. We have shown here that [68Ga]Ga-DFO-c(RGDyK) can be used for αvβ3 integrin targeting, allowing imaging of tumor-induced angiogenesis by positron emission tomography.
- MeSH
- Deferoxamine analogs & derivatives chemical synthesis chemistry MeSH
- Glioblastoma diagnostic imaging MeSH
- Integrin alphaVbeta3 metabolism MeSH
- Humans MeSH
- Mice, Inbred BALB C MeSH
- Mice, Nude MeSH
- Mice MeSH
- Cell Line, Tumor MeSH
- Neovascularization, Pathologic diagnostic imaging MeSH
- Tomography, X-Ray Computed methods MeSH
- Positron-Emission Tomography methods MeSH
- Gallium Radioisotopes chemistry MeSH
- Tissue Distribution MeSH
- Transplantation, Heterologous MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Mice MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Deferoxamine (DFO) represents a widely used iron chelator for the treatment of iron overload. Here we describe the use of mitochondrially targeted deferoxamine (mitoDFO) as a novel approach to preferentially target cancer cells. The agent showed marked cytostatic, cytotoxic, and migrastatic properties in vitro, and it significantly suppressed tumor growth and metastasis in vivo. The underlying molecular mechanisms included (i) impairment of iron-sulfur [Fe-S] cluster/heme biogenesis, leading to destabilization and loss of activity of [Fe-S] cluster/heme containing enzymes, (ii) inhibition of mitochondrial respiration leading to mitochondrial reactive oxygen species production, resulting in dysfunctional mitochondria with markedly reduced supercomplexes, and (iii) fragmentation of the mitochondrial network and induction of mitophagy. Mitochondrial targeting of deferoxamine represents a way to deprive cancer cells of biologically active iron, which is incompatible with their proliferation and invasion, without disrupting systemic iron metabolism. Our findings highlight the importance of mitochondrial iron metabolism for cancer cells and demonstrate repurposing deferoxamine into an effective anticancer drug via mitochondrial targeting. SIGNIFICANCE: These findings show that targeting the iron chelator deferoxamine to mitochondria impairs mitochondrial respiration and biogenesis of [Fe-S] clusters/heme in cancer cells, which suppresses proliferation and migration and induces cell death. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/9/2289/F1.large.jpg.
- MeSH
- Cell Death drug effects MeSH
- PC-3 Cells MeSH
- Iron Chelating Agents administration & dosage MeSH
- Deferoxamine administration & dosage MeSH
- Heme metabolism MeSH
- Carcinogenesis drug effects MeSH
- Humans MeSH
- MCF-7 Cells MeSH
- Mitochondria drug effects metabolism MeSH
- Mitophagy drug effects MeSH
- Mice, Inbred BALB C MeSH
- Mice MeSH
- Neoplasms drug therapy metabolism pathology MeSH
- Cell Movement drug effects MeSH
- Cell Proliferation drug effects MeSH
- Reactive Oxygen Species metabolism MeSH
- Signal Transduction drug effects MeSH
- Tumor Burden drug effects MeSH
- Xenograft Model Antitumor Assays MeSH
- Iron metabolism MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
The patients with mantle cell lymphoma (MCL) have translocation t(11;14) associated with cyclin D1 overexpression. We observed that iron (an essential cofactor of dioxygenases including prolyl hydroxylases [PHDs]) depletion by deferoxamine blocked MCL cells' proliferation, increased expression of DNA damage marker γH2AX, induced cell cycle arrest and decreased cyclin D1 level. Treatment of MCL cell lines with dimethyloxalylglycine, which blocks dioxygenases involving PHDs by competing with their substrate 2-oxoglutarate, leads to their decreased proliferation and the decrease of cyclin D1 level. We then postulated that loss of EGLN2/PHD1 in MCL cells may lead to down-regulation of cyclin D1 by blocking the degradation of FOXO3A, a cyclin D1 suppressor. However, the CRISPR/Cas9-based loss-of-function of EGLN2/PHD1 did not affect cyclin D1 expression and the loss of FOXO3A did not restore cyclin D1 levels after iron chelation. These data suggest that expression of cyclin D1 in MCL is not controlled by ENGL2/PHD1-FOXO3A pathway and that chelation- and 2-oxoglutarate competition-mediated down-regulation of cyclin D1 in MCL cells is driven by yet unknown mechanism involving iron- and 2-oxoglutarate-dependent dioxygenases other than PHD1. These data support further exploration of the use of iron chelation and 2-oxoglutarate-dependent dioxygenase inhibitors as a novel therapy of MCL.
- MeSH
- Amino Acids, Dicarboxylic pharmacology MeSH
- Iron Chelating Agents pharmacology MeSH
- Cyclin D1 metabolism MeSH
- Deferoxamine pharmacology MeSH
- Iron Deficiencies MeSH
- Dioxygenases antagonists & inhibitors metabolism MeSH
- Down-Regulation drug effects MeSH
- Hydroxylation MeSH
- Cell Hypoxia drug effects MeSH
- Enzyme Inhibitors pharmacology MeSH
- Ketoglutaric Acids pharmacology MeSH
- Humans MeSH
- Lymphoma, Mantle-Cell enzymology MeSH
- RNA, Messenger genetics metabolism MeSH
- Cell Line, Tumor MeSH
- DNA Damage MeSH
- Hypoxia-Inducible Factor-Proline Dioxygenases metabolism MeSH
- Forkhead Box Protein O3 genetics metabolism MeSH
- Iron MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Iron and copper release participates in the myocardial injury under ischemic conditions and hence protection might be achieved by iron chelators. Data on copper chelation are, however, sparse. The effect of the clinically used copper chelator D-penicillamine in the catecholamine model of acute myocardial injury was tested in cardiomyoblast cell line H9c2 and in Wistar Han rats. D-Penicillamine had a protective effect against catecholamine-induced injury both in vitro and in vivo. It protected H9c2 cells against the catecholamine-induced viability loss in a dose-dependent manner. In animals, both intravenous D-penicillamine doses of 11 (low) and 44 mg/kg (high) decreased the mortality caused by s.c. isoprenaline (100 mg/kg) from 36% to 14% and 22%, respectively. However, whereas the low D-penicillamine dose decreased the release of cardiac troponin T (specific marker of myocardial injury), the high dose resulted in an increase. Interestingly, the high dose led to a marked elevation in plasma vitamin C. This might be related to potentiation of oxidative stress, as suggested by additional in vitro experiments with D-penicillamine (iron reduction and the Fenton reaction). In conclusion, D-penicillamine has protective potential against catecholamine-induced cardiotoxicity; however the optimal dose selection seems to be crucial for further application.
- MeSH
- Cell Line MeSH
- Iron Chelating Agents pharmacology MeSH
- Deferoxamine pharmacology MeSH
- Ions MeSH
- Cardiotonic Agents chemistry pharmacology MeSH
- Catecholamines MeSH
- Hydrogen-Ion Concentration MeSH
- Myocardium pathology MeSH
- Penicillamine chemistry pharmacology MeSH
- Rats, Wistar MeSH
- Troponin T metabolism MeSH
- Cell Survival drug effects MeSH
- Iron metabolism MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
There is scarce evidence regarding the use of iron chelators in patients with hereditary hemochromatosis who are intolerant of phlebotomy or erythrocytapheresis. A 52-year-old man with genetically confirmed HFE hemochromatosis presented with liver disease and heart failure with severe left ventricular systolic dysfunction. Because of anemia after initial treatment, we added intravenous deferoxamine followed by oral deferiprone to less frequent erythrocytapheresis, which normalized systolic function within 1 year. Repeated cardiac magnetic resonance imaging revealed improvement of the T2* relaxation time. This report illustrates the beneficial effect of iron chelators in individuals with HFE hemochromatosis and poor tolerance of erythrocytapheresis.
- MeSH
- Iron Chelating Agents administration & dosage MeSH
- Deferoxamine administration & dosage MeSH
- Ventricular Dysfunction, Left diagnosis etiology MeSH
- Ferritins analysis MeSH
- Hemochromatosis * blood diagnosis drug therapy physiopathology MeSH
- Cardiomyopathies * diagnosis etiology physiopathology therapy MeSH
- Middle Aged MeSH
- Humans MeSH
- Magnetic Resonance Imaging, Cine methods MeSH
- Liver Diseases diagnosis etiology MeSH
- Iron Overload blood complications MeSH
- Hemochromatosis Protein genetics MeSH
- Pyridones administration & dosage MeSH
- Heart Failure * diagnosis drug therapy etiology MeSH
- Severity of Illness Index MeSH
- Stroke Volume MeSH
- Transferrin analysis MeSH
- Treatment Outcome MeSH
- Check Tag
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Publication type
- Journal Article MeSH
- Case Reports MeSH
- MeSH
- Deferoxamine administration & dosage MeSH
- Humans MeSH
- Iron Overload * diagnosis etiology pathology therapy MeSH
- Hematopoietic Stem Cell Transplantation * adverse effects MeSH
- Check Tag
- Humans MeSH
- Publication type
- Review MeSH
