The strategy change of targeting iron homeostasis for leukemia therapy: from iron chelation to iron overload as a therapeutic strategy to induce ferroptosis / 白血病·淋巴瘤

Iron, an indispensable element for life, is involved in all kinds of vital physiological activities. Due to its potential toxicity, the body has a strict regulation mechanism of iron metabolism to maintain the "iron homeostasis". Dysregulation of iron metabolism and subsequent accumulation of excess iron are closely associated with the development and progression of leukemia. Specifically, due to the pro-oxidative nature of iron and its damaging effects on DNA, excess iron promotes the progression of leukemia; on the other hand, leukemia cells need to obtain more iron than normal cells to maintain rapid growth and proliferation, which is known as "iron addiction". Iron chelators can remove iron in leukemia cells and induce differentiation and apoptosis of leukemia cells. However, "iron addiction" makes leukemia cells more susceptible to iron overload, and is more sensitive to a new form of iron-catalyzed cell death which was named ferroptosis. According to the different needs of leukemia cells and normal cells for iron, the method of selectively killing leukemia cells through iron overload may become a new strategy for leukemia treatment. This paper reviews the strategy of targeting iron homeostasis for leukemia therapy.

Study of anti-diabetic, beta-carotene-bleaching inhibiting and iron chelating properties of Carissa opaca root extracts

Abstract Degenerative diseases diabetes and oxidative stress constitute a major health concern worldwide. Medicinal plants are expected to provide effective and affordable remedies. The present research explored antidiabetic and antioxidant potential of extracts of Carissa opaca roots. Methanolic extract (ME) was prepared through maceration. Its fractions were obtained, sequentially, in hexane, chloroform, ethyl acetate and n-butanol. An aqueous decoction (AD) of the finely ground roots was obtained by boiling in distilled water. The leftover biomass with methanol was boiled in water to obtain biomass aqueous decoction (BAD). The extracts and fractions showed considerable porcine pancreatic α-amylase inhibitory activity with IC50 in the range of 5.38-7.12 mg/mL while acarbose had 0.31 mg/mL. The iron chelating activity in terms of EC50 was 0.2939, 0.3429, 0.1876, and 0.1099 mg/mL for AD, BAD, ME, and EDTA, respectively. The EC50 of beta-carotene bleaching activity for AD, BAD, ME, and standard BHA were 4.10, 4.71, 3.48, and 2.79 mg/mL, respectively. The total phenolic content (TPC) and total flavonoid content (TFC) of AD and BAD were also considerable. In general, ethyl acetate fraction proved to be the most potent. Thus, the C. opaca roots had excellent antioxidant activity while having moderate α-amylase inhibitory potentia

Elevated Iron Chelating Activity of Ilex paraguariensis Leaf Infusion: in vitro and in vivo Pilot Studies

Abstract This study presents an Ilex paraguariensis leaf infusion with important potential as natural iron-chelating. The impact of infusion time and the water volume to obtain an Ilex paraguariensis leaf infusion with high phenolic content and iron chelating activity, such as the stability of these proprieties in the storage time and temperature (immediately and after 24 h at 8 and 25 (C) were assessed. The acute consumption effect of this infusion to reduce iron absorption in vivo was also evaluated. A preliminary crossover trial with volunteers that ingested a meal containing non-haem iron (11.4 mg) with the treatments: Ilex paraguariensis leaf infusion with the highest phenolic content and iron chelating activity (200 mL) or control (200 mL water). Blood samples were withdrawn before and 1, 2, 3 and 4 h after the meal for serum iron measurement. The highest phenolic content (18.1 mg/mL) and iron chelating activity ((100%) were observed for 10 min infusion time using 30 g leaves/300 mL water. Storage at 8 or 25 (C for 24 h decreased total phenolics and di-caffeoylquinic acids by 23.5% and 25.5%, respectively (p< 0.05), without affecting the iron-chelating activity due to a saturating chelating effect at 3.34 mg/mL phenolic content. Inhibition of the iron absorption in vivo by infusion was 78% considering the iron recovery at peak maximum. The in vitro and preliminary in vivo results showed a functional property of the Ilex paraguariensis leaf infusion that may be useful for adjuvant management of iron overload diseases.

Treatment of iron overload syndrome: a general review

SUMMARY INTRODUCTION Iron overload is a broad syndrome with a large spectrum of causative etiologies that lead to iron deposition. When iron exceeds defenses, it causes oxidative damage and tissular disfunction. Treatment may prevent organ dysfunction, leading to greater life expectancy. METHODS Literature from the last five years was reviewed through the use of the PubMed database in search of treatment strategies. DISCUSSION Different pharmacological and non-pharmacological strategies are available for the treatment of iron overload and must be used according to etiology and patient compliance. Therapeutic phlebotomy is the basis for the treatment of hereditary hemochromatosis. Transfusional overload patients and those who cannot tolerate phlebotomy need iron chelators. CONCLUSION Advances in the understanding of iron overload have lead to great advances in therapies and new pharmacological targets. Research has lead to better compliance with the use of oral chelators and less toxic drugs.

RESUMO INTRODUÇÃO A síndrome de sobrecarga de ferro engloba um grande espectro de etiologias que levam a um aumento da quantidade de ferro nos tecidos. Esse ferro excede a capacidade de proteção dos tecidos, levando a dano oxidativo e lesão tissular. Tratamento pode prevenir esse dano, levando à melhor sobrevida. METODOLOGIA A literatura dos últimos cinco anos foi revisada por meio de pesquisa na base de dados PubMed buscando identificar estratégias de tratamento. DISCUSSÃO Medidas farmacológicas e não farmacológicas estão disponíveis para o tratamento da síndrome de sobrecarga de ferro e devem ser utilizadas de acordo com a etiologia e a aceitação do paciente. A flebotomia terapêutica é base do tratamento dos pacientes com hemocromatose hereditária. Pacientes com sobrecarga transfusional ou aqueles que não toleram flebotomias devem utilizar quelantes de ferro. CONSIDERAÇÕES FINAIS Avanços no entendimento da síndrome de sobrecarga de ferro têm levado a grandes progressos na terapêutica, com promessas de abordagem de novos alvos farmacológicos. A evolução da pesquisa tem possibilitado melhor aderência com o uso de quelantes orais e com possibilidade de drogas menos tóxicas.

The effect of combination treatment using iron chelator deferasirox and cisplatin on proliferation and apoptosis in non-small cell lung cancer / 天津医药

Objective To investigate the combination effect using iron chelators deferasirox and cisplatin on A549 cell proliferation and apoptosis and to provide evidences to explore an effective way to treat lung cancer. Methods Lung adeno?carcinoma cells were cultured by conventional way, with administration of different concentrations of deferasirox and cisplat?in. Cell growth inhibition was observed under an inverted microscope. Proliferation inhibition was evaluated by MTT assay. Morphological changes of cell apoptosis was detected using DAPI,AO/EB straning and flow cytometry. Results After a cer?tain time of incubation with different concentrations of the combined drugs,the cell number reduce significantly, which was counted under invert microscope. Cells were dispersed with each other and adherent cells appear shrunken and poor in re?fractivity. MTT assay showed that inhibition of cell proliferation was in a concentration-time-dependent manner. Chromatin condensation, nuclear condensation and other typical apoptotic morphology were detected after DAPI and AO/EB straning. Flow cytometry showed that apoptosis increased with rising drug concentration. So combination therapy was significantly pro-apoptotic. Conclusion Deferasirox has the ability to inhibit proliferation of A549 cells and can promote tumor cell apoptosis and enhances cancer cell tolerance when combined with cisplatin. It can also reduce the amount and toxicity of cis?platin. It provides a basis for finding an effective way to treat lung cancer.

Iron-chelating and anti-lipid peroxidation properties of 1-(N-acetyl-6-aminohexyl)-3-hydroxy-2-methylpyridin-4-one (CM1) in long-term iron loading β-thalassemic mice

Objective: To evaluate the iron-chelating properties and free-radical scavenging activities of 1-(N-acetyl-6-aminohexyl)-3-hydroxy-2-methylpyridin-4-one (CM1) treatment in chronic iron-loaded β-thalassemic (BKO) mice. Methods: The BKO mice were fed with a ferrocene-rich diet and were orally administered with CM1 [50 mg/(kg.day)] for 6 months. Blood levels of non-transferrin bound iron, labile plasma iron, ferritin (Ft) and malondialdehyde were determined. Results: The BKO mice were fed with an iron diet for 8 months which resulted in iron overload. Interestingly, the mice showed a decrease in the non-transferrin bound iron, labile plasma iron and malondialdehyde levels, but not the Ft levels after continuous CM1 treatment. Conclusions: CM1 could be an effective oral iron chelator that can reduce iron overload and lipid peroxidation in chronic iron overload β-thalassemic mice.

Iron-chelating and anti-lipid peroxidation properties of 1-(N-acetyl-6-aminohexyl)-3-hydroxy-2-methylpyridin-4-one (CM1) in long-term iron loading β-thalassemic mice

<p><b>OBJECTIVE</b>To evaluate the iron-chelating properties and free-radical scavenging activities of 1-(N-acetyl-6-aminohexyl)-3-hydroxy-2-methylpyridin-4-one (CM1) treatment in chronic iron-loaded β-thalassemic (BKO) mice.</p><p><b>METHODS</b>The BKO mice were fed with a ferrocene-rich diet and were orally administered with CM1 [50 mg/(kg.day)] for 6 months. Blood levels of non-transferrin bound iron, labile plasma iron, ferritin (Ft) and malondialdehyde were determined.</p><p><b>RESULTS</b>The BKO mice were fed with an iron diet for 8 months which resulted in iron overload. Interestingly, the mice showed a decrease in the non-transferrin bound iron, labile plasma iron and malondialdehyde levels, but not the Ft levels after continuous CM1 treatment.</p><p><b>CONCLUSIONS</b>CM1 could be an effective oral iron chelator that can reduce iron overload and lipid peroxidation in chronic iron overload β-thalassemic mice.</p>

Progress in evaluation and treatment of hepatic iron overload / 临床肝胆病杂志

Iron overload is a metabolic disorder characterized by excessive iron deposition in the liver,pancreas,heart,endocrine organs, etc.,resulting in structural damage and dysfunction.The liver is the primary organ for iron storage,and excessive iron deposition induces liver inflammation and fibrosis,which may progress to cirrhosis and even liver cancer,with a poor prognosis.Accurate evaluation and effec-tive treatment can reduce liver injury caused by iron overload and improve patients′survival.

Ecocardiografia de pacientes talassêmicos sem insuficiência cardíaca em tratamento com transfusões sanguíneas e quelação / Echocardiography in thalassemic patients on blood transfusions and chelation without heart failure

FUNDAMENTO: Pacientes com talassemia major (TM) apresentam hemólise crônica e necessitam de transfusões sanguíneas egularmente que podem causar cardiomiopatia por sobrecarga de ferro e insuficiência cardíaca crônica. A hemocromatose é caracterizada por acúmulo excessivo de ferro nos tecidos; acometimento do coração é a principal causa de óbito em pacientes com talassemia. OBJETIVO: Avaliar as estruturas e a função cardíaca por meio de ecocardiografia com Doppler convencional e Doppler tecidual em pacientes com TM, sem evidência clínica de insuficiência cardíaca. MÉTODOS: Trata-se de estudo observacional prospectivo de 18 pacientes com TM que recebem transfusão sanguínea regularmente. Para avaliar, separadamente, os efeitos da anemia e da transfusão sanguínea, dois grupos controles pareados por gênero, idade, peso e altura foram incluídos: um com indivíduos saudáveis (Saudável, n = 18) e outro com pacientes com anemia por deficiência de ferro (Anemia, n = 18). Análise estatística foi realizada utilizando ANOVA seguida pelo teste de Tukey ou Kruskal-Wallis e teste de Dunn. RESULTADOS: As seguintes variáveis ecocardiográficas apresentaram valores significativamente mais elevados no grupo TM do que nos grupos Anemia e Saudável: índice de volume do átrio esquerdo (Saudável: 16,4 ± 6,08; Anemia: 17,9 ± 7,02; TM: 24,1 ± 8,30 cm/m); razão E/Em septal mitral (Saudável: 6,55 ± 1,60; Anemia: 6,74 ± 0,74; TM: 8,10 ± 1,31) e duração do fluxo reverso em veias pulmonares [Saudável: 74,0 (59,0-74,0); Anemia: 70,5 (67,0-74,0); TM: 111 (87,0-120) ms]. Arazão E/A mitral foi maior no grupo TM do que no grupo Anemia (Saudável: 1,80 ± 0,40; Anemia: 1,80 ± 0,24; TM: 2,03 ± 0,34). Não foram encontradas diferenças entre os grupos em variáveis estruturais do ventrículo esquerdo e em índices de função sistólica. CONCLUSÃO: A ecocardiografia com Doppler convencional e o Doppler tecidual permite que alterações na função diastólica do ventrículo esquerdo sejam identificadas em pacientes assintomáticos com talassemia major.

BACKGROUND: Patients with thalassemia major present chronic hemolysis and require regular blood transfusions which may cause iron overload cardiomyopathy and chronic heart failure. Hemochromatosis is characterized by excessive iron accumulation in tissues, and heart involvement is the main cause of death in patients with thalassemia. OBJECTIVE: The aim of this study was to evaluate cardiac structure and function by conventional Doppler echocardiography and tissue Doppler imaging in patients with TM and no clinical evidence of heart failure. METHODS: This is a prospective observational study including 18 patients with thalassemia major (TM) receiving regular blood transfusion. To separately evaluate anemia and blood transfusion effects, two gender, age, weight, and height-matched control groups were included: one with healthy individuals (Healthy, n=18) and one with iron deficient anemia patients (Anemia, n=18). Statistical analysis was performed using ANOVA followed by Tukey's test or Kruskal-Wallis's and Dunn's test. RESULTS: The following echocardiographic variables presented significantly higher values in TM than the Anemia and Healthy groups: left atrium volume index (Healthy: 16.4±6.08; Anemia: 17.9±7.02; TM: 24.1±8.30 cm³/m²); mitral septal E/Em ratio (Healthy: 6.55±1.60; Anemia: 6.74±0.74; TM: 8.10±1.31); and duration of reverse pulmonary vein flow [Healthy: 74.0 (59.0-74.0); Anemia: 70.5 (67.0-74.0); TM: 111 (87.0-120) ms]. The mitral E/A ratio was higher in TM than Anemia (Healthy: 1.80±0.40; Anemia: 1.80±0.24; TM: 2.03±0.34). No differences were found in left ventricular structures and systolic function indexes. CONCLUSION: Conventional Doppler echocardiography and tissue Doppler allow changes in left ventricular diastolic function to be identified in asymptomatic patients with thalassemia major.

Brazilian Thalassemia Association protocol for iron chelation therapy in patients under regular transfusion

In the absence of an iron chelating agent, patients with beta-thalassemia on regular transfusions present complications of transfusion-related iron overload. Without iron chelation therapy, heart disease is the major cause of death; however, hepatic and endocrine complications also occur. Currently there are three iron chelating agents available for continuous use in patients with thalassemia on regular transfusions (desferrioxamine, deferiprone, and deferasirox) providing good results in reducing cardiac, hepatic and endocrine toxicity. These practice guidelines, prepared by the Scientific Committee of Associação Brasileira de Thalassemia (ABRASTA), presents a review of the literature regarding iron overload assessment (by imaging and laboratory exams) and the role of T2* magnetic resonance imaging (MRI) to control iron overload and iron chelation therapy, with evidence-based recommendations for each clinical situation. Based on this review, the authors propose an iron chelation protocol for patients with thalassemia under regular transfusions.

Anti-tumour activity of iron chelators and copper chelators: Research advances / 国际药学研究杂志

Iron and copper are the essential trace elements in human body. The contents of iron and copper in neoplastic cells are much higher than those in the normal ones. The deprivation of excess iron and copper in tumor cells can inhibit the proliferation of tumor cells, DNA synthesis, the fomiation of vessels and generate active oxygen species, which may induce cellular injury. Therefore, iron chelators and copper chelatois as important anti-tumor agents are increasingly attracting our attention. In this parper, the recent advances of iron chelators and copper chelators are reviewed. © 2006 Editorial office of Foreign Medical Sciences.

Progress in iron chelators: the report of the 53rd annual meeting of American Society of Hematology / 白血病·淋巴瘤

Chelation therapy could remove transfusional iron burden. Three chelators are currently available, including deferoxamine, deferiprone, and deferasirox, which can be used as monotherapy or in combination.Several factors must be considered in the design of optimal and individualized chelation regimens,which include chelator availability and its properties,degree of organ-specific iron loading,ongoing transfusional iron burden, and patient preference. Comparative effectiveness trials may help to determine the ideal strategy. This article reviews latest research presented at the 53rd annual meeting of the American Society of Hematology (ASH) on the use of iron chelators.

Tratamento da anemia ferropriva com ferro quelato glicinato e crescimento de crianças na primeira infância / Treatment of iron deficiency anemia with iron bis-glycinate chelate and growth of young children

Objetivo: Avaliar a resposta à suplementação diária com ferro quelato glicinato e seu impacto sobre o crescimento linear. Métodos: Realizou-se um estudo prospectivo com 790 crianças, de 6 a 36 meses, que freqüentavam creches municipais de São Paulo no período de 1999 a 2003. Ao início e ao final do estudo a hemoglobina, o peso corporal e a estatura/comprimento foram coletados. Utilizou-se suplemento contendo ferro quelato glicinato em gotas na dose de 5mg Fe elementar/kg peso/dia, administrado na própria instituição pelo profissional de saúde da creche, por um período de 12 semanas. Resultados: A suplementação resultou em um significante e positivo efeito sobre os níveis de hemoglobina. A resposta ao tratamento foi positiva em 85,3% das crianças, com um aumento médio de 1,6g/dL nos valores de hemoglobina(p<0,001). Nas crianças de 25-36 meses e naquelas com valores de hemoglobina mais baixas ao início da suplementação, observou-se ganho significantemente maior. Durante o período de intervenção não foi observada nenhuma intercorrência gastrintestinal ou intolerância ao suplemento. Verificou-se também impacto sobre o ganho de estatura e o indicador nutricional estatura/idade (escore-Z) nas crianças com idade acimade 12 meses, porém o mesmo não foi observado em relação ao peso e aos indicadores peso/estatura e peso/idade. Conclusão Os resultados indicam que o ferro quelato glicinato é um suplemento adequado para tratamento da anemiaferropriva em crianças na primeira infância, pela sua excelente tolerabilidade contribuindo também para o ganho de estatura entre crianças acima de 12 meses.

Objective: The objective of this study was to evaluate response to daily supplementation with iron bis-glycinate chelate and its impact on linear growth.Methods: A prospective study was done with 790 children aging from 6 to 36 months who attended daycare in SãoPaulo from 1999 to 2003. Hemoglobin levels, body weight and height/length were determined at the beginning and end of the study. Liquid iron bis-glycinate chelate was administered in a dosage of 5mg of elemental iron/kg of body weight/day given by the health provider of the daycare facility for a period of 12 weeks. Results: Supplementation resulted in a significant, positive effect on the hemoglobin levels of 85.3% of the children with a mean increase of 1.6g/dL (p<0.001). In children aging from 25 to 36 months and in those with lower hemoglobin levels at the beginning of supplementation, there was a significantly higher increase. No gastrointestinal problem or intolerance to the supplement was observed during the intervention period. Supplementation also had an impact on growth and on the height-for-age indicator (z-score) in children older than 12 months but there was no impact on weight and on the weight-for-height and weight-for-age indicators. Conclusion: The results show that iron bis-glycinate chelate is an adequate supplement to treat iron deficiency anemia in young children since it is very well tolerated and promotes growth in children older than 12 months.

Economic Evaluation of Iron Chelation Agents: Oral Deferasirox versus Infusional Deferoxamine / 대한혈액학회지

BACKGROUND: Patients with transfusional iron overload have relied on treatment with deferoxamine, a standard chelating agent. Deferoxamine is administered by intravenous or subcutaneous infusion over an 8~12 hour period 5~7 times per week; however, administration of deferoxamine may lead to poor compliance and reduced quality of life in patients. The use of deferasirox, a once daily oral chelation agent, was recently approved. We conducted an economic evaluation of these two iron-chelating medications in transfusion-dependent patients. METHODS: The efficacy of oral deferasirox and infusion deferoxamine was assumed equal based on clinical trials of non-inferiority with the administration of 20mg/kg/day deferasirox versus 40mg/kg/day deferoxamine. Depending on the methods utilized for measuring administration time, travel time and convenience between the use of infusion and oral therapy, either cost analysis or cost-utility analysis was undertaken, respectively. Cost analysis included determination of direct medical costs (drug costs and administration costs), non-medical costs (travel costs), and indirect costs (productivity loss associated medical utilization). For cost utility analysis, the cost per QALYs (quality-adjusted life years) was calculated based on costs subtracting indirect costs (productivity loss) and gains of QALYs between the two agents. RESULTS: Deferasirox therapy resulted in a cost savings per patient of 23,471,777 Korean won based on cost analysis. Based on cost utility analysis, the cost per QALYs gained was -398,576 Korean won (4,527,819 Korean won savings with a gain of 11.5 QALYs per patient). CONCLUSION: The results of cost analysis and cost utility analysis of the use of oral deferasirox versus infusion deferoxamine showed that deferasirox is a more economical and potentially socially beneficial iron-chelating agent in Korea.

The Clinical Guidelines for Myelodysplastic Syndrome / 대한혈액학회지

The myelodysplastic syndromes (MDS) are characterized by ineffective hematopoiesis associated with multilineage cytopenias leading to serious morbidity or mortality, and the additional risk of leukemic transformation. The management of patients with MDS can be very complex and varies according to both the clinical manifestations in individual patients as well as the presence of complicating medical conditions. However, therapeutic dilemmas still exist for MDS due to the multifactorial pathogenetic features of the disease, its heterogeneous stages, and the elderly patient population. For these reasons, proper guidelines for management are necessary. This review describes the proper diagnosis for MDS, decision-making approaches for optimal therapeutic options that are based on a consideration of patient clinical factors and risk-based prognostic categories, and the use of recently available biospecific drugs such as hypomethylating agents that are potentially capable of abrogating the abnormalities associated with MDS. Proper indications and methods for transplantation, response criteria, management for iron overload for highly transfused patients and specific considerations for MDS in childhood are also described. All of these topics were discussed at the third symposium of AML/MDS working party on 3 March, 2007.

Bacterial Growth in Amniotic Fluid Is Dependent on the Iron-Availability and the Activity of Bacterial Iron-Uptake System

In the present study, the relationship among iron-availability, antibacterial activity, role of meconium as an iron source and the activity of bacterial iron-uptake system (IUS) for bacterial growth in amniotic fluid (AF) were investigated. Staphylococcus aureus ATCC 6538 and its streptonigrin-resistant (SR) mutant with defective IUS were used as the test strains. The growth of S. aureus in AF was stimulated dosedependently by addition of meconium. Bacterial growth stimulated by meconium was re-inhibited dose-dependently by addition of iron-chelator, dipyridyl and apotransferrin. Iron concentration was correlated with the meconium content in AF (r(2)= 0.989, p=0.001). High-affinity IUS of S. aureus was expressed only in AF but not in AF with meconium. The growth of SR strain was more retarded than that of the parental strain in the iron-deficient brain heart infusion (ID-BHI), clear AF and AF containing apotransferrin. The retarded growth of both strains in the ID-BHI and AF was recovered by addition of holotransferrin, hemoglobin and FeCl3. Taken together, the antibacterial activity of AF is closely related with low iron-availability. Bacterial growth in AF considerably depends on the activity of bacterial IUS. Meconium acts as one of the exogenous iron-sources and thus can stimulate bacterial growth in AF.

High brain iron in etiology of Alzheimer's disease and therapeutic approaches / 中国药理学通报

Excessive iron accumulation in the brain occurs in Alzheimer' s disease (AD) with oxidative stress,amyloid deposition,tau phosphorylation,and neuronal cell cycle regulatory failure,leading to apoptosis.Therefore,there is a direct link between iron metabolism and AD pathogenesis. The present review elaborates on high brain iron in etiology of AD and the development of iron-chelating therapy for AD,aiming at preventing or slowing down disease evolution.