An iron chelation-based combinatorial anticancer therapy comprising deferoxamine and a lactate excretion inhibitor inhibits the proliferation of cancer cells

Rational synthesis of FeNiCo-LDH nanozyme for colorimetric detection of deferoxamine mesylate

The accurate surveillance and sensitive detection of deferoxamine mesylate (DFO) is of great significance to ensure the safety of thalassemia major patients. Herein, we report a new nanozyme-based colorimetric sensor platform for DFO detection. First, a metal-organic framework (ZIF-67) was used as a precursor for the synthesis of FeNiCo-LDH (Layered Double Hydroxide, LDH) via an ion exchange reaction stirring at room temperature. The results of electron microscopy and nitrogen adsorption-desorption showed that FeNiCo-LDH exhibited a 3D hollow and mesopores structure, which supplied more exposed active sites and faster transfer of mass. The as-prepared FeNiCo-LDH showed superior peroxidase-like activity with a low Km and high υmax. It can catalyze the decomposition of H2O2 to generate reactive oxygen species (ROS) and further react with 3,3',5,5'-tetramethylbenzidine (TMB) to form blue oxidized TMB (oxTMB), which has a characteristic absorption at 652 nm. Once DFO was introduced, it can complex with FeNiCo-LDH and inhibit the peroxidase-like activity of FeNiCo-LDH, making the color of oxTMB lighter. The quantitative range of DFO was 0.8-28 μM with a detection limit of 0.71 μM. This established method was applied to the detection of DFO content in urine samples of thalassemia patients, and the spiked recoveries were falling between 97.7% and 109.6%, with a relative standard deviation was less than 5%, providing a promising tool for the clinical medication of thalassemia patients.

Depletion of Labile Iron Induces Replication Stress and Enhances Responses to Chemoradiation in Non-Small-Cell Lung Cancer

The intracellular redox-active labile iron pool (LIP) is weakly chelated and available for integration into the iron metalloproteins that are involved in diverse cellular processes, including cancer cell-specific metabolic oxidative stress. Abnormal iron metabolism and elevated LIP levels are linked to the poor survival of lung cancer patients, yet the underlying mechanisms remain unclear. Depletion of the LIP in non-small-cell lung cancer cell lines using the doxycycline-inducible overexpression of the ferritin heavy chain (Ft-H) (H1299 and H292), or treatment with deferoxamine (DFO) (H1299 and A549), inhibited cell growth and decreased clonogenic survival. The Ft-H overexpression-induced inhibition of H1299 and H292 cell growth was also accompanied by a significant delay in transit through the S-phase. In addition, both Ft-H overexpression and DFO in H1299 resulted in increased single- and double-strand DNA breaks, supporting the involvement of replication stress in the response to LIP depletion. The Ft-H and DFO treatment also sensitized H1299 to VE-821, an inhibitor of ataxia telangiectasis and Rad2-related (ATR) kinase, highlighting the potential of LIP depletion, combined with DNA damage response modifiers, to alter lung cancer cell responses. In contrast, only DFO treatment effectively reduced the LIP, clonogenic survival, cell growth, and sensitivity to VE-821 in A549 non-small-cell lung cancer cells. Importantly, the Ft-H and DFO sensitized both H1299 and A549 to chemoradiation in vitro, and Ft-H overexpression increased the efficacy of chemoradiation in vivo in H1299. These results support the hypothesis that the depletion of the LIP can induce genomic instability, cell death, and potentiate therapeutic responses to chemoradiation in NSCLC.

Opportunities and challenges of microbial siderophores in the medical field

Siderophores are low-molecular-weight secondary metabolites that function as iron chelators. Under iron-deficiency conditions, they are produced by a wide variety of microbes, allowing them to increase their iron uptake. The primary function of these compounds is the environmental iron scavenging and its transport into the cytosol. Iron is then reduced to its ferrous form to operate as an enzymatic cofactor for various functions, including respiration, nitrogen fixation, photosynthesis, methanogenesis, and amino acid synthesis. Depending on their functional group, siderophores are classified into hydroxamate, catecholate, phenolate, carboxylate, and mixed types. They have achieved great importance in recent years due to their medical applications as antimicrobial, antimalarial, or anticancer drugs, vaccines, and drug-delivery agents. This review integrates current advances in specific healthcare applications of microbial siderophores, delineating new opportunities and challenges as viable therapies to fight against diseases that represent crucial public health problems in the medical field.Key points• Siderophores are low-molecular-weight secondary metabolites functioning as iron chelators.• The siderophore's properties offer viable options to face diverse clinical problems.• Siderophores are alternatives for the enhancement of antibiotic activities.

Metabolic Analysis of DFO-Resistant Huh7 Cells and Identification of Targets for Combination Therapy

Hepatocellular carcinoma (HCC) is one of the most refractory cancers with a high rate of recurrence. Iron is an essential trace element, and iron chelation has garnered attention as a novel therapeutic strategy for cancer. Since intracellular metabolism is significantly altered by inhibiting various proteins by iron chelation, we investigated combination anticancer therapy targeting metabolic changes that are forcibly modified by iron chelator administration. The deferoxamine (DFO)-resistant cell lines were established by gradually increasing the DFO concentration. Metabolomic analysis was conducted to evaluate the metabolic alterations induced by DFO administration, aiming to elucidate the resistance mechanism in DFO-resistant strains and identify potential novel therapeutic targets. Metabolom analysis of the DFO-resistant Huh7 cells revealed enhanced glycolysis and salvage cycle, alternations in glutamine metabolism, and accumulation of dipeptides. Huh7 cultured in the absence of glutamine showed enhanced sensitivity to DFO, and glutaminase inhibitor (CB839) showed a synergistic effect with DFO. Furthermore, the effect of DFO was enhanced by an autophagy inhibitor (chloroquine) in vitro. DFO-induced metabolic changes are specific targets for the development of efficient anticancer combinatorial therapies using DFO. These findings will be useful for the development of new cancer therapeutics in refractory liver cancer.

Magnetospirillum magneticum triggers apoptotic pathways in human breast cancer cells

The use of bacteria in cancer immunotherapy has the potential to bypass many shortcomings of conventional treatments. The ability of anaerobic bacteria to preferentially accumulate and replicate in hypoxic regions of solid tumors, as a consequence of bacterial metabolic needs, is particularly advantageous and key to boosting their immunostimulatory therapeutic actions in situ. While several of these bacterial traits are well-studied, little is known about their competition for nutrients and its effect on cancer cells which could serve as another potent and innate antineoplastic action. Here, we explored the consequences of the iron-scavenging abilities of a particular species of bacteria, Magnetospirillum magneticum, which has been studied as a potential new class of bacteria for magnetically targeted bacterial cancer therapy. We investigated their influence in hypoxic regions of solid tumors by studying the consequential metabolic effects exerted on cancer cells. To do so, we established an in vitro co-culture system consisting of the bacterial strain AMB-1 incubated under hypoxic conditions with human breast cancer cells MDA-MB-231. We first quantified the number of viable cells after incubation with magnetotactic bacteria demonstrating a lower rate of cellular proliferation that correlated with increasing bacteria-to-cancer cells ratio. Further experiments showed increasing populations of apoptotic cells when cancer cells were incubated with AMB-1 over a period of 24 h. Analysis of the metabolic effects induced by bacteria suggest an increase in the activation of executioner caspases as well as changes in levels of apoptosis-related proteins. Finally, the level of several human apoptosis-related proteins was investigated, confirming a bacteria-dependent triggering of apoptotic pathways in breast cancer cells. Overall, our findings support that magnetotactic bacteria could act as self-replicating iron-chelating agents and indicate that they interfere with proliferation and lead to increased apoptosis of cancer cells. This bacterial feature could serve as an additional antineoplastic mechanism to reinforce current bacterial cancer therapies.

Unbalanced T-cell subsets in pediatric patients with beta-thalassemia

BACKGROUND

Beta-thalassemia major is an autosomal recessive disorder in hemoglobin synthesis. Ineffective erythropoiesis is the main characteristic of the disease, which results in anemia following the extensive destruction of red blood cells. Chronic antigenic stimulation following frequent blood transfusions lead to immune abnormalities, especially regarding T cells, which is one of the reasons for the high susceptibility to infection in beta-thalassemia.

METHODS

Six pediatric patients and six age- and sex-matched healthy children were selected. Immunophenotyping of functional T-cells was performed using flow cytometry with staining for surface and intracellular markers. The proliferative response of T lymphocytes was also investigated after labeling with CFSE and following stimulation with anti-CD3 and anti-CD28.

RESULTS

Examination of T lymphocyte subpopulations showed a significant increase in regulatory T cells (Tregs) in beta-thalassemia patients. Hence, the Treg:Tcons (conventional T cells) and Treg:CD8 ratios were significantly increased. In addition, a significant increase in CD8 T cell proliferation activity was observed. Multivariate analysis showed a significant association of central memory cells with serum ferritin levels and the duration of transfusion. In particular, patients with cytomegalovirus (CMV) infection exhibited a significant increase in CD4 central memory cells.

CONCLUSION

Patients with beta-thalassemia have functionally distinct CD4 and CD8 T cell subsets imbalances, and this may contribute to their high susceptibility to infections and immune dysregulation.

Ultraviolet Radiation Promoted Hypoxia-Induced Apoptosis in HL-60 Human Promyelocytic Leukemia Cell Line

Minimal residual disease (MRD) is an important reason for the failure of autologous hematopoietic stem cell transplantation (auto-HSCT). Reducing MRD in grafts is particularly important to improve the efficacy of auto-HSCT. Previously, we reported that ultraviolet light-emitting diode (UV LED) suppressed the expression of Bcl-2 to induce apoptosis in HL-60 cells. Leukemia can lead to severe hypoxia of the bone marrow. Therefore, this study aimed to investigate the effect of UV LED on leukemia cells under hypoxia. HL-60 cells were irradiated with a UV LED (30 J/m²) and simulated under hypoxia with cobalt chloride. We found that UV LED irradiation or CoCl₂ inhibited proliferation, induced apoptosis, decreased the Bcl-2/Bax ratio, and increased the levels of caspase 3, cleaved-caspase 3, and caspase 9 in HL-60 cells. In particular, the combined application of UV and CoCl₂ significantly enhanced the apoptosis of HL-60 cells. In conclusion, UV LED in hypoxia exacerbated the inhibition of proliferation and induction of apoptosis and necrosis in HL-60 cells via the regulation of caspase 3/9 and the Bcl-2/Bax ratio-dependent pathway. The application of UV LEDs in hypoxia conditions may be a promising approach to kill residual drug-resistant leukemia cells in autologous grafts.

ION MODULATORY TREATMENTS TOWARD FUNCTIONAL SELF-ASSEMBLED NEOCARTILAGE

Signals that recapitulate in vitro the conditions found in vivo, such as hypoxia or mechanical forces, contribute to the generation of tissue-engineered hyaline-like tissues. The cell regulatory processes behind hypoxic and mechanical stimuli rely on ion concentration; iron is required to degrade the hypoxia inducible factor 1a (HIF1α) under normoxia, whereas the initiation of mechanotransduction requires the cytoplasmic increase of calcium concentration. In this work, we propose that ion modulation can be used to improve the biomechanical properties of self-assembled neocartilage constructs derived from rejuvenated expanded minipig rib chondrocytes. The objectives of this work were 1) to determine the effects of iron sequestration on self-assembled neocartilage constructs using two doses of the iron chelator deferoxamine (DFO), and 2) to evaluate the performance of the combined treatment of DFO and ionomycin, a calcium ionophore that triggers cytoplasmic calcium accumulation. This study employed a two-phase approach. In Phase I, constructs treated with a high dose of DFO (100 µM) exhibited an 87% increase in pyridinoline crosslinks, a 57% increase in the Young's modulus, and a 112% increase in the ultimate tensile strength (UTS) of the neotissue. In Phase II, the combined use of both ion modulators resulted in 150% and 176% significant increases in the Young's modulus and UTS of neocartilage constructs, respectively; for the first time, neocartilage constructs achieved a Young's modulus of 11.76±3.29 MPa and UTS of 4.20±1.24 MPa. The results of this work provide evidence that ion modulation can be employed to improve the biomechanical properties in engineered neotissues. STATEMENT OF SIGNIFICANCE: : The translation of tissue-engineered products requires the development of strategies capable of producing biomimetic neotissues in a replicable, controllable, and cost-effective manner. Among other functions, Fe²⁺ and Ca²⁺ are involved in the control of the hypoxic response and mechanotransduction, respectively. Both stimuli, hypoxia and mechanical forces, are known to favor chondrogenesis. This study utilized ion modulators to improve the mechanical properties self-assembled neocartilage constructs derived from expanded and rejuvenated costal chondrocytes via Fe²⁺ sequestration and Ca²⁺ influx, alone or in combination. The results indicate that ion modulation induced tissue maturation and a significant improvement of the mechanical properties, and holds potential as a tool to mitigate the need for bioreactors and engineer hyaline-like tissues.