Differentiation-Dependent Doxorubicin Toxicity on H9c2 Cardiomyoblasts

A characteristic component of the anti-neoplastic doxorubicin (DOX)-induced cardiac toxicity is the delayed and persistent toxicity, with cancer childhood survivors developing cardiac failure later in life. The mechanisms behind this persistent toxicity are unknown, although one of the consequences of early childhood treatment with DOX is a specific removal of cardiac progenitor cells. DOX treatment may be more toxic to undifferentiated muscle cells, contributing to impaired cardiac development and toxicity persistence. H9c2 myoblasts, a rat embryonic cell line, which has the ability to differentiate into a skeletal or cardiac muscle phenotype, can be instrumental in understanding DOX cytotoxicity in different differentiation stages. H9c2 cell differentiation results in decreased cell proliferation and increased expression of a differentiated muscle marker. Differentiated H9c2 cells accumulated more DOX and were more susceptible to DOX-induced cytotoxicity. Differentiated cells had increased levels of mitochondrial superoxide dismutase and Bcl-xL, an anti-apoptotic protein. Of critical importance for the mechanisms of DOX toxicity, p53 appeared to be equally activated regardless of the differentiation state. We suggest that although more differentiated H9c2 muscle cells appear to have more basal mechanisms that would predict higher protection, DOX toxicity is higher in the differentiated population. The results are instrumental in the understanding of stress responses of this specific cell line in different differentiation stages to the cardiotoxicity caused by anthracyclines.     

Endurance training attenuates doxorubicin-induced cardiac oxidative damage in mice

BACKGROUND: There is a lack of studies reporting the influence of DOX treatment on chronically exercised animals. This study intended to determine the effect of endurance swimming training on cardiac muscle tolerance to in vivo DOX-induced damage, analyzing the levels of oxidative stress markers, the response of antioxidant system and the expression of 60 and 70 kDa heat shock proteins (HSP). METHODS: Forty-four Charles River CD1 male mice were randomly assigned to either non-trained placebo (NT+P) and non-trained DOX (NT+DOX) or trained placebo (T+P) and trained DOX (T+DOX). Twenty-four hours after completion of a 14-week training, cardiac ventricles were extracted for biochemical assays of oxidative stress and damage markers, antioxidant enzymes and HSPs. RESULTS: DOX treatment per se (single 20 mg kg(-1) dose), administrated 24 h after the last exercise bout, elevated (p<0.05) plasma cardiac troponin I (cTnI), HSP60, % oxidized glutathione, thiobarbituric acid reactive substances and carbonyl groups and reduced -SH groups. However, training induced a significant increase (p<0.05) on total and reduced glutathione (GSH), HSP60 expression, and decreased the rise of plasma cTnI as well as cardiac carbonyl groups contents in DOX hearts, when compared to NT+DOX mice. Although catalase activity of T+DOX was significantly higher than T+P, no changes were observed in the activities of superoxide dismutase, glutathione peroxidase and glutathione reductase. Neither DOX nor training induced significant variations in HSP70. CONCLUSION: Training improved myocardial tolerance to DOX-induced damage. It is likely that the improvement in responses to DOX was related to training-induced increases in GSH and HSP60.     

鲁斯可皂苷元通过抑制p38MAPK途径及心肌细胞焦亡改善小鼠阿霉素心肌病

目的 观察和探索鲁斯可皂苷元(Rus)对小鼠阿霉素(DOX)心肌病的影响及可能机制,旨在为临床上DOX心脏毒性的预防和治疗提供参考依据.方法 通过单次腹腔注射DOX(15mg/kg)的方式构建急性DOX心肌病小鼠模型,采用随机数表法将32只雄性C57BL/6小鼠(8～10周)随机分为空白对照组(Sham组)、Rus组、...     

A Chemosensitizer Drug: Disulfiram Prevents Doxorubicin-Induced Cardiac Dysfunction and Oxidative Stress in Rats

In the present study, the preventive effects of orally administered disulfiram (DS) against the doxorubicin (DOX)-induced cardiotoxicity were investigated in rats. DS was orally administered for 7 days at doses of 2, 10, and 50 mg/kg/day. DOX (30 mg/kg) was intraperitoneally administered on the 5th day of the initiation of DS treatment. Within 48 h of injection, DOX treatment significantly altered ECG, elevated the ST height, and increased the QT and QRS intervals. It reduced the cardiac levels of injury markers like creatine kinase isoenzyme-MB and lactate dehydrogenase. DOX elevated the serum levels of SGOT and nitric oxide. Its injection significantly induced lipid peroxidation in the cardiac tissue and reduced the activities of innate antioxidants like super oxide dismutase, catalase, and reduced glutathione in the cardiac tissue. DOX treatment raised the TNF-α level and caused histological alterations in the myocardium like neutrophil infiltrations, myonecrosis, and edema. Pre-treatment of rats with DS (2, 10, and 50 mg/kg p. o. for 7 days) prevented the ECG changes, minimized oxidative stress, and normalized the biochemical indicators of the DOX-induced cardiotoxicity. DS also protected rat heart from DOX-induced histological alterations. Recently, DS is reported to exert chemosensitization of cancer cells. Our in vitro investigation using MCF7 cell line revealed that DS reverses the DOX-induced suppression of NF-κB and Nrf2 expression. These findings about the protective activity of DS against the DOX-induced cardiotoxicity warrant a detailed investigation on its utility as an adjunct therapy to cancer chemotherapy.     

Aldehyde dehydrogenase 2 ameliorates doxorubicin-induced myocardial dysfunction through detoxification of 4-HNE and suppression of autophagy

Mitochondrial aldehyde dehydrogenase (ALDH2) protects against cardiac injury via reducing production of 4-hydroxynonenal (4-HNE) and ROS. This study was designed to examine the impact of ALDH2 on doxorubicin (DOX)-induced cardiomyopathy and mechanisms involved with a focus on autophagy. 4-HNE and autophagic markers were detected by Western blotting in ventricular tissues from normal donors and patients with idiopathic dilated cardiomyopathy. Cardiac function, 4-HNE and levels of autophagic markers were detected in WT, ALDH2 knockout or ALDH2 transfected mice treated with or without DOX. Autophagy regulatory signaling including PI-3K, AMPK and Akt was examined in DOX-treated cardiomyocytes incubated with or without ALDH2 activator Alda-1. DOX-induced myocardial dysfunction, upregulation of 4-HNE and autophagic proteins were further aggravated in ALDH2 knockout mice while they were ameliorated in ALDH2 transfected mice. DOX downregulated Class I and upregulated Class III PI3-kinase, the effect of which was augmented by ALDH2 deletion. Accumulation of 4-HNE and autophagic protein markers in DOX-induced cardiomyocytes was significantly reduced by Alda-1. DOX depressed phosphorylated Akt but not AMPK, the effect was augmented by ALDH2 knockout. The autophagy inhibitor 3-MA attenuated, whereas autophagy inducer rapamycin mimicked DOX-induced cardiomyocyte contractile defects. In addition, rapamycin effectively mitigated Alda-1-offered protective action against DOX-induced cardiomyocyte dysfunction. Our data further revealed downregulated ALDH2 and upregulated autophagy levels in the hearts from patients with dilated cardiomyopathy. Taken together, our findings suggest that inhibition of 4-HNE and autophagy may be a plausible mechanism underscoring ALDH2-offered protection against DOX-induced cardiac defect. This article is part of a Special Issue entitled “Protein Quality Control, the Ubiquitin Proteasome System, and Autophagy”.     

Role of HMGB1 in doxorubicin-induced myocardial apoptosis and its regulation pathway

Doxorubicin (DOX) is a widely used anti-tumor agent. The clinical application of the medication is limited by its side effect which can elicit myocardial apoptosis and cardiac dysfunction. However, the underlying mechanism by which DOX causes cardiomyocyte apoptosis is not clear. The aim of present study is to investigate the role of high-mobility group box 1 (HMGB1) in DOX-induced myocardial injury, and signal pathway involved in regulation of HMGB1 expression in cardiomyocytes with DOX. We found treatment of isolated cardiomyocytes and naive mice with the DOX resulted in an increased HMGB1 expression which was associated with increased myocardial cell apoptosis. Pharmacological (A-box) or genetic blockade (TLR4 deficiency, TLR4(-/-)) of HMGB1 attenuated the DOX-induced myocardial apoptosis and cardiac dysfunction. In addition, our study showed that DOX resulted in an increment in the generation of peroxynitrite (ONOO(-)) and an elevation in phosphorylation of c-Jun N terminal kinase (JNK). Pretreatment of myocytes with FeTPPS, a peroxynitrite decomposition catalyst, prevented DOX-induced JNK phosphorylation, HMGB1 expression, myocardial apoptosis and cardiac dysfunction. Genetic (JNK(-/-)) or pharmacological (SP600125) inhibition of JNK ameliorated the DOX-induced HMGB1 expression and diminished myocardial apoptosis and cardiac dysfunction. Taken together, our results indicate that HMGB1 mediates the myocardial injury induced by DOX and ONOO(-)/JNK is a key regulatory pathway of myocardial HMGB1 expression induced by DOX.     

Gene expression patterns of human colon tops and basal crypts and BMP antagonists as intestinal stem cell niche factors

Human colonic epithelial cell renewal, proliferation, and differentiation are stringently controlled by numerous regulatory pathways. To identify genetic programs of human colonic epithelial cell differentiation in vivo as well as candidate marker genes that define colonic epithelial stem/progenitor cells and the stem cell niche, we applied gene expression analysis of normal human colon tops and basal crypts by using expression microarrays with 30,000 genes. Nine hundred and sixty-nine cDNA clones were found to be differentially expressed between human colon crypts and tops. Pathway analysis revealed the differential expression of genes involved in cell cycle maintenance and apoptosis, as well as genes in bone morphogenetic protein (BMP), Notch, Wnt, EPH, and MYC signaling pathways. BMP antagonists gremlin 1, gremlin 2, and chordin-like 1 were found to be expressed by colon crypts. In situ hybridization and RT-PCR confirmed that these BMP antagonists are expressed by intestinal cryptal myofibroblasts and smooth muscle cells at the colon crypt. In vitro analysis demonstrated that gremlin 1 partially inhibits Caco-2 cell differentiation upon confluence and activates Wnt signaling in normal rat intestinal epithelial cells. Collectively, the expression data set provides a comprehensive picture of human colonic epithelial cell differentiation. Our study also suggests that BMP antagonists are candidate signaling components that make up the intestinal epithelial stem cell niche.     

骨形态发生蛋白和白血病抑制因子诱导肝干细胞分化

目的 在永生化的小鼠肝干（祖）细胞(HP)模型上筛选并优化高效的肝细胞定向分化诱导方法,探讨HP向肝细胞定向分化过程及分子机制。 方法分别采用含人白血病抑制因子(LIF)、骨形态发生蛋白(BMP)2和BMP9基因的重组腺病毒感染HP,在病毒感染后第4天、第7天和第10天用糖原染色和吲哚花青绿(ICG)摄取实验观察HP的分化成熟度,并在第4、7、10、14天通过检测白蛋白启动子调控的荧光素酶报告基因活性,观察细胞合成白蛋白情况。计量资料比较用t检验。结果 BMP2和BMP9对HP的诱导作用最强,荧光素酶活性、PAS染色和ICG摄取细胞阳性率随诱导时间的延长明显上升,在诱导后第7天最高,HP对BMP9的诱导应答最强,与对照组相比,酶活性增加了近9倍（t=17.30,P＜0.01）,BMP2处理组增加了5倍（t=16.41,P＜0.01）,LIF处理组增加了3倍（t=6.04,P＜0.01）。诱导第7天时,PAS染色细胞阳性率在BMP2和BMP9组分别为30％和45％; ICG细胞阳性率在BMP2和BMP9组分别为40％和30％。LIF诱导后,PAS染色、ICG摄取细胞阳性率以及荧光素酶活性有一定增加。结论 BMP2、BMP9和LIF能够诱导HP向发育晚期肝细胞分化,并初步具备成熟肝细胞的一些功能。     

Bone morphogenetic protein 2 is expressed by, and acts upon, mature epithelial cells in the colon

BACKGROUND AND AIMS: The recent findings of bone morphogenetic protein (BMP) receptor Ia mutations in juvenile polyposis and frequent Smad4 mutations in colon cancer suggest a role for BMPs in the colonic epithelium and colon cancer. We investigated the role of BMP2 in the colon. METHODS: We assessed BMP receptor expression in cell lines using the reverse-transcribed polymerase chain reaction and immunoblotting. We investigated the effect of BMP2 on cell lines using the MTT assay and by immunoblotting for markers of differentiation, proliferation, and apoptosis. We assessed the expression of BMP2, its receptors, and signal transduction elements in mouse and human colon tissue using immunohistochemistry. We also investigated the effect of the BMP antagonist noggin in vivo in mice by assessing colon tissue with immunohistochemistry and immunoblotting. Finally, we investigated the expression of BMP2 in microadenomas from familial adenomatous polyposis patients. RESULTS: BMP receptors (BMPR) Ia, BMPR Ib, and BMPR II are all expressed in colonic epithelial cell lines. BMP2 inhibits colonic epithelial cell growth in vitro, promoting apoptosis and differentiation and inhibiting proliferation. BMP2, BMPRIa, BMPRIb, BMPRII, phosphorylated Smad1, and Smad4 are expressed predominantly in mature colonocytes at the epithelial surface in normal adult human and mouse colon. Noggin inhibits apoptosis and proliferation in mouse colonic epithelium in vivo. BMP2 expression is lost in the microadenomas of familial adenomatous polyposis patients. CONCLUSIONS: These data suggest that BMP2 acts as a tumor suppressor promoting apoptosis in mature colonic epithelial cells.     

Aging of the prostate epithelial stem/progenitor cell

Maintenance of the prostatic epithelial cell compartment is ensured by proliferation of adult epithelial progenitor or stem cells. These cells are characterized by an undifferentiated state, high proliferative capacity and long life span. Prostate progenitor/stem cells are localized in their stem cell-niche in the basal cell compartment in close contact to the basement membrane and the stromal cell compartment and are characterized by expression of the basal cytokeratins 5 and 14, high levels of integrins, CD44, the stem cell markers CD133 and ABCG2, and AR negativity. They give rise to secretory luminal (cytokeratins 8/18, CD57, AR, p27, PSA, PAP) and neuroendocrine cells (cytokeratins 8/18, CD57, CgA, NSE, NEPs), the two major cell types observed in the glandular epithelium. A growing body of experimental evidence has identified the amplifying progenitor/stem cell (CD44(+), alpha(2)beta(1)(hi), CD133(+)), as a putative origin of prostate cancer. Differentiation of this cell type can be affected by mutations in the intrinsic genetic program, by age-related changes in stromal-epithelial interactions or in the basement membrane/ECM composition. All these stochastic events occur during aging and can transform a normal prostate progenitor/stem cell into a cancer stem cell, a source of androgen-dependent and independent tumor cell clones. Thus, the heterogeneous and multifocal nature of prostatic cancer with a pleora of different tumor cell clones clearly reflects the differentiation capacity of the prostatic epithelial progenitor cells.     

BMP-4 induced proliferation and oriented differentiation of rat hepatic oval cells into hepatocytes

Objective:To explore the role of bone morphogenetic protein 4(BMP-4) in hepatic progenitor cells(HPCs).Methods:The effect of BMP-4 on rat hepatic oval cells was examined by using the WB-F344 rat hepatocytic epithelial stem-cell-like cell line.This hepatocytic cell line could exert various hepatocytc functions including the secretion of albumin and urea.Immunohistochemistry was used to examine the effects of BMP-4 and its antagonist,Noggin,on the proliferation and differentiation of these cells,cellular uptake and excretion of indocyanine green,the periodic acid-schiff(PAS) assay for glycogen storage and the expression of hepatic markers.Results:Our results showed for the first time that BMP-4 may acted as a potential inducer of hepatic differentiation in rat hepatic oval cells.Conclusions:This cell source offers a much-needed attractive and expandable source for future investigations of drug screening,stem cell technologies and cellular transplantation,in a society with increasing levels of liver disease and damage.     

Induction of cardiac myogenic lineage development differs between mesenchymal and satellite cells and is accelerated by bone morphogenetic protein-4

Our aim was to further elucidate the cardiac lineage development of bone marrow-derived mesenchymal stem cells (MSC) and to identify cells which had the potential for cardiac myogenic differentiation when compared to skeletal muscle satellite (Sk-sat) myogenesis. Unlike Sk-sat, MSC expressed the early cardiac markers Nkx2.5 and GATA4. Their expression was significantly increased by culturing MSC with Bone Morphogenetic Protein 4 (BMP4). Enhanced cardiac myogenic lineage differentiation and loss of stem cell characteristics induced by BMP4 were further confirmed by flow cytometry of cells stained for Nkx2.5 and Sca-1 expression. MSC also expressed skeletal genes (MyoG, ssTnI, Sk-Act) early in culture but their expression was suppressed when BMP4 was added from day 0 to day 6 (p<0.05). BMP4 treated MSC also exhibited a 6-fold increase in cTnI expression by day 12 in culture. The average MSC action potential time duration at 90% (APD90) was 32.3±4ms, with some cells exhibiting action potentials closer to Sk-sat APD90 of 13.7±0.9ms. After treatment with BMP4, MSC significantly increased their APD90 to 54.4±7.6ms, shifting from the shorter skeletal-like signature, towards a longer action potential duration more characteristic of a cardiomyocyte signature. Our results show that MSC and Sk-sat exhibit similarities in myogenic lineage development early in culture but that BMP4 clearly enhances cardiac myogenic development, suppresses skeletal myogenesis, and leads to loss of "stemness" in MSC. These findings provide novel information regarding the use of BMP4 to accelerate cardiac myogenic development in harvested MSC and further support the use of MSC in cardiac regenerative therapy.     

Prevention of doxorubicin-induced experimental cardiotoxicity by Nigella sativa in rats

IntroductionDoxorubicin (DOX) is an anthracycline cytotoxic chemotherapeutic drug that is commonly used in cancer treatment. A major side effect limiting the clinical use of DOX is cardiotoxicity due to oxidative injury. Nigella sativa (NS) is an annual flowering plant with antioxidant properties. Its seeds contain several bioactive constituents such as saturated and unsaturated fatty acids, thymoquinone, dithymoquinone, thymohydroquinone, and thymol. In this study, we investigated the effect of NS extract on DOX-induced cardiotoxicity.MethodsThe experimental study animals consisted of 28 male Sprague Dawley rats weighing between 300 and 400 g. Four study groups each of seven rats were defined: controls; NS extract; DOX; and DOX+NS. Control and DOX rats received standard food, while each rat in the NS and DOX+NS groups also received 100 mg/kg NS extract orally. At day 28 of follow-up, rats in the DOX groups were administered a single 10 mg/kg intraperitoneal dose of DOX, while rats in the control and NS groups received a single 10 mg/kg dose of physiological saline solution. All animals were monitored for 35 days. On day 35, the rats were decapitated and serum and cardiac tissue samples were obtained. Troponin and NT-proBNP levels were measured in blood sera, while malondialdehyde (MDA), nitric oxide, total antioxidant capacity (TAC), and total oxidative stress (TOS) levels were quantified in sera and tissue samples. Histological alterations that were assessed in cardiac tissue included myocyte disarray, small vessel disease, myocyte hypertrophy, and fibrosis.ResultsThe DOX group had significantly higher NT-proBNP, TOS, and MDA, with greater histopathological derangement. TAC was significantly elevated in the DOX+NS group, which also exhibited significantly lower troponin, TOS, and MDA, as well as significantly higher TAC compared to the DOX group. Histopathological examination showed that the significant structural derangement observed in DOX rats was markedly and significantly reduced in DOX+NS rats.ConclusionOur results suggest that NS extract may prevent DOX-induced cardiotoxicity and thus represents a promising cardioprotective agent.     

Efeito Cardioprotetor da Suplementação Materna com Resveratrol sobre a Toxicidade Induzida por Doxorrubicina em Cardiomiócitos de Neonatos

BackgroundDoxorubicin (DOX) is frequently used to treat many types of cancers, despite its dose-dependent cardiotoxicity. Alternatively, resveratrol is a polyphenol that has shown useful cardioprotective effects in many heart dysfunction models.ObjectiveThis study investigated whether resveratrol treatment in pregnant rats protects against doxorubicin-induced toxicity in offspring cardiomyocytes.MethodsWistar rats (n=8) were supplemented with dietary resveratrol during pregnancy. Upon the offspring’s birth, hearts (9-11) were used to obtain the primary culture of cardiomyocytes. DOX-induced cardiotoxicity and the effects of resveratrol supplementation were evaluated by oxidative stress markers, such as dichlorofluorescein diacetate oxidation, decrease in the activity of antioxidant enzymes, and oxidation of total sulfhydryl content, in addition to cell viability evaluation, DNA damage generation, and DNA damage repair response. A value of p<0.05 was considered statistically significant.ResultsNeonatal cardiomyocytes from resveratrol supplemented rats exhibiting an increase (p<0.01) in cell viability and lower (p<0.0001) apoptotic/necrotic cells after DOX treatment, which correlates with the activities of antioxidant enzymes and dichlorofluorescein production. Moreover, resveratrol protected cardiomyocytes from DOX-induced DNA damage, showing a decrease (p<0.05) in DNA breaks induced by oxidative stress, evaluated by the activity of DNA-repair enzymes endonuclease III and formamidopyrimidine glycosylase. Supplementation with resveratrol increased (p<0.05) the expression of the repair protein Sirt6 in the cardiomyocytes of the pups.ConclusionThis research indicates that supplementation with resveratrol during the gestational period has a notable cardioprotective effect on the offspring’s heart against DOX-induced toxicity, which may well be due to its antioxidant function, and the increase in the DNA damage repair response.     

柚皮苷通过调控p38MAPK通路保护H9c2心肌细胞对抗多柔比星引起的炎症反应

目的 探讨柚皮苷（naringin,NRG）能否通过调控p38丝裂原激活蛋白激酶（mitogen-activated protein kinase,MAPK）通路保护H9c2心肌细胞对抗多柔比星（doxorubicin,DOX）引起的炎症反应.方法 应用5μmol·L-1 DOX处理H9c2心肌细胞建立DOX心肌毒性损伤模型.CCK-8比色法检测细胞存活率;Westem blot法测定p38MAPK蛋白表达水平;酶联免疫吸附试验（ELISA）试剂盒检测肿瘤坏死因子-α（TNF-α）、白细胞介素-1β（IL-1β）和白细胞介素-6（IL-6）浓度.结果 在5μmol·L-1 DOX处理H9c2心肌细胞前,应用1μmol·L-1 NRG预处理150 min能明显抑制DOX引起的心肌细胞毒性,使细胞存活率升高,并能抑制5μmol·L-1 DOX对磷酸化（p）p38MAPK表达的上调作用;5μmol· L-1 DOX能引起H9c2心肌细胞产生炎症反应,表现为肿瘤坏死因子-α、白细胞介素-1β和白细胞介素-6水平明显升高;1μmol· L-1 NRG预处理150 min或3μmol·L-1 SB203580（为p38MAPK抑制剂）预处理60 min均能抑制DOX对肿瘤坏死因子-α、白细胞介素-1β和白细胞介素-6水平的升高作用及抑制DOX诱发的心肌细胞毒性.结论 NRG通过抑制p38MAPK通路保护H9c2心肌细胞对抗DOX引起的炎症反应及细胞毒性.     

Sildenafil increases chemotherapeutic efficacy of doxorubicin in prostate cancer and ameliorates cardiac dysfunction

We have shown that the potent phosphodiesterase-5 (PDE-5) inhibitor sildenafil (Viagra) induces a powerful effect on reduction of infarct size following ischemia/reperfusion injury and improvement of left ventricular dysfunction in the failing heart after myocardial infarction or doxorubicin (DOX) treatment. In the present study, we further investigated the potential effects of sildenafil on improving antitumor efficacy of DOX in prostate cancer. Cotreatment with sildenafil enhanced DOX-induced apoptosis in PC-3 and DU145 prostate cancer cells, which was mediated by enhanced generation of reactive oxygen species, up-regulation of caspase-3 and caspase-9 activities, reduced expression of Bcl-xL, and phosphorylation of Bad. Overexpression of Bcl-xL or dominant negative caspase 9 attenuated the synergistic effect of sildenafil and DOX on prostate cancer cell killing. Furthermore, treatment with sildenafil and DOX in mice bearing prostate tumor xenografts resulted in significant inhibition of tumor growth. The reduced tumor size was associated with amplified apoptotic cell death and increased expression of activated caspase 3. Doppler echocardiography showed that sildenafil treatment ameliorated DOX-induced left ventricular dysfunction. In conclusion, these results provide provocative evidence that sildenafil is both a powerful sensitizer of DOX-induced killing of prostate cancer while providing concurrent cardioprotective benefit.     

Hfe deficiency increases susceptibility to cardiotoxicity and exacerbates changes in iron metabolism induced by doxorubicin

The clinical use of doxorubicin (DOX), an anthracycline chemotherapeutic agent, is limited by cardiotoxicity. The possible involvement of iron in DOX-induced cardiotoxicity became evident from studies in which iron chelators were shown to be cardioprotective. Iron overload is found in hereditary hemochromatosis, a genetic disorder prevalent in individuals of European descent. We hypothesized that Hfe deficiency may increase susceptibility to DOX-induced toxicity. Acute cardiotoxicity and iron changes were studied after treatment with DOX in Hfe knock-out (Hfe-/-) mice and wild-type mice. DOX-induced iron metabolism changes were intensified in Hfe-/- mice, which accumulated significantly more iron in the heart, liver, and pancreas, but less in the spleen compared with wild-type mice. In addition, Hfe-deficient mice exhibited significantly greater sensitivity to DOX-induced elevations in serum creatine kinase and aspartate aminotransferase. Increased mortality after chronic DOX treatment was observed in Hfe-/- mice and Hfe+/-mice compared with wild-type mice. DOX-treated Hfe-/- mice had a higher degree of mitochondrial damage and iron deposits in the heart than did wild-type mice. These data demonstrate that Hfe deficiency in mice increases susceptibility to DOX-induced cardiotoxicity and suggest that genetic mutations related to defects in iron metabolism may contribute to its cardiotoxicity in humans.