Effects of Deferoxamine on Leukemia In Vitro and Its Related Mechanism

Iron chelators: as therapeutic agents in diseases

The concentration of iron is tightly regulated, making it an essential element. Various cellular processes in the body rely on iron, such as oxygen sensing, oxygen transport, electron transfer, and DNA synthesis. Iron excess can be toxic because it participates in redox reactions that catalyze the production of reactive oxygen species and elevate oxidative stress. Iron chelators are chemically diverse; they can coordinate six ligands in an octagonal sequence. Because of the ability of chelators to trap essential metals, including iron, they may be involved in diseases caused by oxidative stress, such as infectious diseases, cardiovascular diseases, neurodegenerative diseases, and cancer. Iron-chelating agents, by tightly binding to iron, prohibit it from functioning as a catalyst in redox reactions and transfer iron and excrete it from the body. Thus, the use of iron chelators as therapeutic agents has received increasing attention. This review investigates the function of various iron chelators in treating iron overload in different clinical conditions.

Polymeric iron chelators for enhancing 5-aminolevulinic acid-induced photodynamic therapy

5-Aminolevulinic acid (5-ALA) is an amino acid that can be metabolized into a photosensitizer, protoporphyrin IX (PpIX) selectively in a tumor cell, permitting minimally invasive photodynamic diagnosis/therapy. However, some malignant tumor cells have excess intracellular labile iron and facilitate the conversion of PpIX into heme, which compromises the therapeutic potency of 5-ALA. Here, we examined the potential of chelation of such unfavorable intratumoral labile iron in photodynamic therapy (PDT) with 5-ALA hydrochloride, using polymeric iron chelators that we recently developed. The polymeric iron chelator efficiently inactivated the intracellular labile iron in cultured cancer cells and importantly enhanced the accumulation of PpIX, thereby improving the cytotoxicity upon photoirradiation. Even in in vivo study with subcutaneous tumor models, the polymeric iron chelator augmented the intratumoral accumulation of PpIX and the PDT effect. This study suggests that our polymeric iron chelator could be a tool for boosting the effect of 5-ALA-induced PDT by modulating tumor microenvironment.

From iron chelation to overload as a therapeutic strategy to induce ferroptosis in hematologic malignancies

OBJECTIVES

Ferroptosis is an iron-dependent, non-apoptotic mode of cell death characterized by excessive accumulation of reactive oxygen species (ROS). It plays an important role in the occurrence, development and treatment of various cancers, but little is known regarding the role of ferroptosis in hematologic malignancies. This review elaborates the regulatory mechanism of ferroptosis and the treatment opportunities for targeting ferroptosis in hematologic malignancies.

METHODS

A systematic literature review through PubMed was conducted to summarize the published evidence on the therapeutic potential of targeting ferroptosis in hematological malignant tumors. Literature sources published in English were searched, using the terms ferroptosis, leukemia, myelodysplastic syndrome, lymphoma and multiple myeloma.

RESULTS

More and more small molecules have been found to induce ferroptosis in hematologic malignancies through targeted iron metabolism and lipid peroxidation, and some ferroptosis inducers have been proved to have synergistic effect with other chemotherapeutic drugs.

CONCLUSION

This paper discusses the significance of ferroptosis in hematologic malignancies and provides a new way for the treatment of hematologic malignancies, and more experimental studies should be conducted in future.

Understanding the Potential and Risk of Bacterial Siderophores in Cancer

Siderophores are iron chelating molecules produced by nearly all organisms, most notably by bacteria, to efficiently sequester the limited iron that is available in the environment. Siderophores are an essential component of mammalian iron homeostasis and the ongoing interspecies competition for iron. Bacteria produce a broad repertoire of siderophores with a canonical role in iron chelation and the capacity to perform versatile functions such as interacting with other microbes and the host immune system. Siderophores are a vast area of untapped potential in the field of cancer research because cancer cells demand increased iron concentrations to sustain rapid proliferation. Studies investigating siderophores as therapeutics in cancer generally focused on the role of a few siderophores as iron chelators; however, these studies are limited and some show conflicting results. Moreover, siderophores are biologically conserved, structurally diverse molecules that perform additional functions related to iron chelation. Siderophores also have a role in inflammation due to their iron acquisition and chelation properties. These diverse functions may contribute to both risks and benefits as therapeutic agents in cancer. The potential of siderophore-mediated iron and bacterial modulation to be used in the treatment of cancer warrants further investigation. This review discusses the wide range of bacterial siderophore functions and their utilization in cancer treatment to further expand their functional relevance in cancer detection and treatment.

Deferoxamine Inhibits Acute Lymphoblastic Leukemia Progression through Repression of ROS/HIF-1α, Wnt/β-Catenin, and p38MAPK/ERK Pathways

Acute lymphoblastic leukemia (ALL) is the most common type of childhood cancer, with a feature of easy to induce multidrug resistance and relapse. Abundant studies have proved that iron overload strengthens the growth and metastasis of tumor cells. Herein, we found that deferoxamine (DFO) effectively decreased the concentration of intracellular iron in ALL cells. DFO inhibited proliferation, induced apoptosis, and obstructed cell cycle of ALL cells, whereas DFO and dextriferron (Dex) used in combination significantly decreased the sensitivity of ALL cells to DFO. Reactive oxygen species (ROS) level was reduced in ALL cells treated with DFO, and the combination of DFO and Dex reversed the effects of DFO. In vivo, DFO inhibited mouse tumor growth. Besides, cyclinD1, β-catenin, c-Myc, hypoxia inducible factor 1 (HIF-1), p-p38MAPK, and p-ERK1/2 protein levels were significantly downregulated, and the levels of prolyl hydroxylase-2 (PHD-2) were upregulated after treated with DFO, whereas Dex treatment reversed those in vivo and in vitro. In conclusion, DFO inhibited the proliferation and ALL xenograft tumor growth, obstructed the cell cycle, and induced apoptosis of ALL cells, probably via inactivating the ROS/HIF-1α, Wnt/β-catenin, and p38MAPK/ERK signaling.

Prognostic biomarkers for predicting papillary thyroid carcinoma patients at high risk using nine genes of apoptotic pathway

Aberrant expressions of apoptotic genes have been associated with papillary thyroid carcinoma (PTC) in the past, however, their prognostic role and utility as biomarkers remains poorly understood. In this study, we analysed 505 PTC patients by employing Cox-PH regression techniques, prognostic index models and machine learning methods to elucidate the relationship between overall survival (OS) of PTC patients and 165 apoptosis related genes. It was observed that nine genes (ANXA1, TGFBR3, CLU, PSEN1, TNFRSF12A, GPX4, TIMP3, LEF1, BNIP3L) showed significant association with OS of PTC patients. Five out of nine genes were found to be positively correlated with OS of the patients, while the remaining four genes were negatively correlated. These genes were used for developing risk prediction models, which can be utilized to classify patients with a higher risk of death from the patients which have a good prognosis. Our voting-based model achieved highest performance (HR = 41.59, p = 3.36x10^-4, C = 0.84, logrank-p = 3.8x10^-8). The performance of voting-based model improved significantly when we used the age of patients with prognostic biomarker genes and achieved HR = 57.04 with p = 10⁻⁴ (C = 0.88, logrank-p = 1.44x10^-9). We also developed classification models that can classify high risk patients (survival ≤ 6 years) and low risk patients (survival > 6 years). Our best model achieved AUROC of 0.92. Further, the expression pattern of the prognostic genes was verified at mRNA level, which showed their differential expression between normal and PTC samples. Also, the immunostaining results from HPA validated these findings. Since these genes can also be used as potential therapeutic targets in PTC, we also identified potential drug molecules which could modulate their expression profile. The study briefly revealed the key prognostic biomarker genes in the apoptotic pathway whose altered expression is associated with PTC progression and aggressiveness. In addition to this, risk assessment models proposed here can help in efficient management of PTC patients.

Deferoxamine-Modified Hybrid Materials for Direct Chelation of Fe(III) Ions from Aqueous Solutions and Indication of the Competitiveness of In Vitro Complexing toward a Biological System

Deferoxamine (DFO) is one of the most potent iron ion complexing agent belonging to a class of trihydroxamic acids. The extremely high stability constant of the DFO-Fe complex (log β = 30.6) prompts the use of deferoxamine as a targeted receptor for scavenging Fe(III) ions. The following study aimed at deferoxamine immobilization on three different supports: poly(methyl vinyl ether-alt-maleic anhydride), silica particles, and magnetite nanoparticles, leading to a class of hybrid materials exhibiting effectiveness in ferric ion adsorption. The formed deferoxamine-loaded hybrid materials were characterized with several analytical techniques. Their adsorptive properties toward Fe(III) ions in aqueous samples, including pH-dependence, isothermal, kinetic, and thermodynamic experiments, were investigated. The materials were described with high values of maximal adsorption capacity q _m, which varied between 87.41 and 140.65 mg g^-1, indicating the high adsorptive potential of the DFO-functionalized materials. The adsorption processes were also described as intense, endothermic, and spontaneous. Moreover, an exemplary magnetically active deferoxamine-modified material has been proven for competitive in vitro binding of ferric ions from the biological complex protoporphyrin IX-Fe(III), which may lead to a further examination of the materials' biological or medical applicability.

Reversing oncogenic transformation with iron chelation

Cancer cells accumulate iron to supplement their aberrant growth and metabolism. Depleting cells of iron by iron chelators has been shown to be selectively cytotoxic to cancer cells in vitro and in vivo. Iron chelators are effective at combating a range of cancers including those which are difficult to treat such as androgen insensitive prostate cancer and cancer stem cells. This review will evaluate the impact of iron chelation on cancer cell survival and the underlying mechanisms of action. A plethora of studies have shown iron chelators can reverse some of the major hallmarks and enabling characteristics of cancer. Iron chelators inhibit signalling pathways that drive proliferation, migration and metastasis as well as return tumour suppressive signalling. In addition to this, iron chelators stimulate apoptotic and ER stress signalling pathways inducing cell death even in cells lacking a functional p53 gene. Iron chelators can sensitise cancer cells to PARP inhibitors through mimicking BRCAness; a feature of cancers trademark genomic instability. Iron chelators target cancer cell metabolism, attenuating oxidative phosphorylation and glycolysis. Moreover, iron chelators may reverse the major characteristics of oncogenic transformation. Iron chelation therefore represent a promising selective mode of cancer therapy.

The iron chelator deferoxamine decreases myeloma cell survival

OBJECTIVE

This study evaluated serum ferritin (SF) levels and investigated their relationships with various clinical markers in patients with multiple myeloma (MM). Furthermore, the effects and molecular mechanism of deferoxamine (DFO) in myeloma cells were studied.

METHODS

Clinical data from 84 patients with MM were collected to evaluate SF content and its relationship with several important clinical parameters. MM1S and MM1R myeloma cells were chosen to investigate the effects of iron and DFO on cell survival and apoptosis.

RESULTS

Increased SF levels were detected in newly diagnosed patients, especially those with stage III disease or the κ isotype. SF content was positively correlated with β2-microglobulin, interleukin-6, and lactate dehydrogenase expression. Furthermore, patients with progressive or relapsed disease had higher SF levels. Importantly, iron chelation with DFO efficiently inhibited myeloma cell survival and accelerated apoptosis by regulating apoptosis-related genes.

CONCLUSIONS

The importance of SF for MM was highlighted. Additionally, it is suggested that DFO may be a good therapeutic option for MM.

Iron chelation cancer therapy using hydrophilic block copolymers conjugated with deferoxamine

Cancer cells have high iron requirements due to their rapid growth and proliferation. Iron depletion using iron chelators has a potential in cancer treatment. Previous studies have demonstrated that deferoxamine (DFO) specifically chelates Fe(III) and exhibited antitumor activity in clinical studies. However, its poor pharmacokinetics has limited the therapeutic potential and practical application. Although polymeric iron chelators have been developed to increase the blood retention, none of previous studies has demonstrated their potential in iron chelation cancer therapy. Here, we developed polymeric DFO by the covalent conjugation of DFO to poly(ethylene glycol)‐poly(aspartic acid) (PEG‐PAsp) block copolymers. The polymeric DFO exhibited iron‐chelating ability comparable with free DFO, thereby arresting cell cycle and inducing apoptosis and antiproliferative activity. After intravenous administration, the polymeric DFO showed marked increase in blood retention and tumor accumulation in subcutaneous tumor models. Consequently, polymeric DFO showed significant suppression of the tumor growth compared with free DFO. This study reveals the first success of the design of polymeric DFO for enhancing iron chelation cancer therapy.

miR-18a Inhibitor Suppresses Leukemia Cell Proliferation by Upregulation of PTEN Expression

Background

Leukemia is common in aging adults and has very high mortality worldwide. The present study was designed to investigate the therapeutic efficacy of miR-18a inhibitor against WEHI-3 and THP-1 leukemia cells.

Material/Methods

The changes in miR-18a inhibitor-transfected WEHI-3 and THP-1 cell proliferative potential was measured by use of the Cell Counting Kit-8 assay. Apoptotic changes were analyzed by electron microscopy, and evaluation of PI3K, AKT, mTOR, and PTEN expression was assessed by RT-qPCR assay.

Results

Transfection of miR-18a inhibitor significantly (P<0.05) suppressed the proliferative potential of WEHI-3 and THP4 cells. The WEHI-3 cells showed the presence of characteristic apoptotic bodies on transfection with miR-18a inhibitor at 48 h. Flow cytometry showed that miR-18a inhibitor transfection significantly (P<0.05) increased the WEHI-3 cell percentage in G1 phase. The transfection of miR-18a inhibitor significantly (P<0.05) promoted apoptosis in WEHI-3 cells. In WEHI-3 cells, miR-18a inhibitor transfection markedly suppressed the expression of PI3K, AKT, and mTOR mRNA. The expression of PTEN mRNA was significantly (P<0.05) upregulated by miR-18a inhibitor transfection in WEHI-3 cells.

Conclusions

The present study investigated the therapeutic efficacy of miR-18a inhibitor against WEHI-3 and THP1 leukemia cells. The study demonstrated that miR-18a inhibitor suppressed the proliferative potential of WEHI-3 and THP1 cells and activated apoptotic process through upregulation of PTEN mRNA expression. Therefore, miR-18a inhibitor can be of therapeutic importance for the treatment of leukemia.

Repurposing Drugs by In Silico Methods to Target BCR Kinase Domain in Chronic Myeloid Leukemia

BACKGROUND

Targeted therapy in the form of highly selective tyrosine kinase inhibitors (TKIs) has transformed the treatment of chronic myeloid leukemia (CML). However, mutations in the kinase domain contribute to drug resistance against TKIs which compromises the treatment response. Our aim is to explore regions outside the BCR-ABL oncoprotein to identify potential therapeutic targets to curb drug resistance by targeting growth factor receptor-bound protein-2 (Grb-2) which binds to BCR-ABL at the phosphorylated tyrosine (Y177) thereby activating the Ras and PI3K/AKT signaling pathway.

METHODS

We have used in silico methods to repurpose drugs for identifying their potential to inhibit the binding of Grb-2 with Y177 by occupying the active binding site of the BCR domain.

RESULTS

Differentially expressed genes from GEO dataset were found to be associated with hematopoietic cell lineage, NK cell-mediated cytotoxicity, NF-κB and chemokine signaling, cytokine-cytokine receptor interaction, histidine metabolism and transcriptional misregulation in cancer. The fold recognition method of SPARKS-X tool was used to model the BCR domain (Z-score = 8.21). Connectivity Map generated a drug list based on the gene expression profile, which were docked with BCR. Schrodinger XP glide docking identified Diphosphopyridine nucleotide, Hesperidin, Butirosin, Ovoflavin, and Nor-dihydroguaiaretic acid to show strong interaction in close proximity to the active binding pocket containing Y177 of the target protein and was further validated using iGEMDOCK and Parallelized Open Babel and AutoDock suite Pipeline (POAP).

CONCLUSION

Our study not only extends our current knowledge about repurposing drugs for newer indications but also provides a route towards combinatorial therapy with standard drugs used for CML treatment. However, the efficacy of these repurposed drugs needs to be further investigated using in vitro and in vivo studies.<br />.