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Immunohistochemical detection of apoptotic cells in the heart (TUNEL staining). Representative images of cardiac tissue treated with Saline, Drz, Dox, Drz + Dox, 0.3 mg/kg Dp44mT, and Dp44mT + Dox are shown (200£ magniWcation ). Tissues were embedded in paraYn and sectioned to 5 m. A positive reaction of DNA fragmentation is indicated by a blue color (marked by arrows) (color Wgure online)
Source publication
The iron chelator Dp44mT is a potent topoisomerase IIα inhibitor with novel anticancer activity. Doxorubicin (Dox), the current front-line therapy for breast cancer, induces a dose-limiting cardiotoxicity, in part through an iron-mediated pathway. We tested the hypothesis that Dp44mT can improve clinical outcomes of treatment with Dox by alleviatin...
Citations
... The hypothesis of iron-dependent ROS production as a mechanism of anthracycline-related cardiotoxicity has been challenged by a number of studies that did not prove effectiveness of iron chelators in preventing anthracycline-induced cardiomyopathy [167]. However, there is an association between mutations predisposing to iron overload, and susceptibility to doxorubicin damage supports this mechanism of toxicity [168]. ...
Anthracyclines are effective chemotherapeutic agents, commonly used in the treatment of a variety of hematologic malignancies and solid tumors. However, their use is associated with a significant risk of cardiovascular toxicities and may result in cardiomyopathy and heart failure. Cardiomyocyte toxicity occurs via multiple molecular mechanisms, including topoisomerase II-mediated DNA double-strand breaks and reactive oxygen species (ROS) formation via effects on the mitochondrial electron transport chain, NADPH oxidases (NOXs), and nitric oxide synthases (NOSs). Excess ROS may cause mitochondrial dysfunction, endoplasmic reticulum stress, calcium release, and DNA damage, which may result in cardiomyocyte dysfunction or cell death. These pathophysiologic mechanisms cause tissue-level manifestations, including characteristic histopathologic changes (myocyte vacuolization, myofibrillar loss, and cell death), atrophy and fibrosis, and organ-level manifestations including cardiac contractile dysfunction and vascular dysfunction. In addition, these mechanisms are relevant to current and emerging strategies to diagnose, prevent, and treat anthracycline-induced cardiomyopathy. This review details the established and emerging data regarding the molecular mechanisms of anthracycline-induced cardiovascular toxicity.
... The hypothesis that mitochondrial oxidative damage caused by iron-induced ROS production has been challenged by the findings that several iron chelator failed to protect from DOXmediated cardiotoxicity (Simunek et al., 2009;Rao et al., 2011). However, iron chelators such as Dexrazoxane have been used as a preventive therapy. ...
... DOX also causes DNA fragmentation-associated apoptosis in endothelial cells (Kaushal et al., 2004). Importantly, vascular endothelial growth factor (VEGF)-B gene therapy reduces DOX-induced apoptosis in endothelial cells and recovers capillary rarefaction, thereby ameliorating the cardiac function in mouse hearts (Rasanen et al., 2016). In accord with this data, VEGF receptor-1 (VEGFR1) has been predominantly found in the cardiac endothelial cells (Kalivendi et al., 2001). ...
Cardiotoxicity is one of the main adverse effects of chemotheraphy, affecting the completion of cancer therapies and the short- and long-term quality of life. Anthracyclines are currently used to treat many cancers, including the various forms of leukemia, lymphoma, melanoma, uterine, breast, and gastric cancers. World Health Organization registered anthracyclines in the list of essential medicines. However, anthracyclines display a major cardiotoxicity that can ultimately culminate in congestive heart failure. Taking into account the growing rate of cancer survivorship, the clinical significance of anthracycline cardiotoxicity is an emerging medical issue. In this review, we focus on the key progenitor cells and cardiac cells (cardiomyocytes, fibroblasts, and vascular cells), focusing on the signaling pathways involved in cellular damage, and the clinical biomarkers in anthracycline-mediated cardiotoxicity.
... II. Doxorubicin [27], the current front-line therapy for breast cancer, not only activated MAPK pathway as carmustine, but also up-regulated EGFR/PKC pathway. In addition, treatment with Doxorubicin also decreased the expression of ATM/BRCA1, HSP90/ NFKB, and PI3K/AKT/BAD pathways (see Additional file 3: Figure S2). ...
Background:
In recent years, the integration of 'omics' technologies, high performance computation, and mathematical modeling of biological processes marks that the systems biology has started to fundamentally impact the way of approaching drug discovery. The LINCS public data warehouse provides detailed information about cell responses with various genetic and environmental stressors. It can be greatly helpful in developing new drugs and therapeutics, as well as improving the situations of lacking effective drugs, drug resistance and relapse in cancer therapies, etc.
Results:
In this study, we developed a Ternary status based Integer Linear Programming (TILP) method to infer cell-specific signaling pathway network and predict compounds' treatment efficacy. The novelty of our study is that phosphor-proteomic data and prior knowledge are combined for modeling and optimizing the signaling network. To test the power of our approach, a generic pathway network was constructed for a human breast cancer cell line MCF7; and the TILP model was used to infer MCF7-specific pathways with a set of phosphor-proteomic data collected from ten representative small molecule chemical compounds (most of them were studied in breast cancer treatment). Cross-validation indicated that the MCF7-specific pathway network inferred by TILP were reliable predicting a compound's efficacy. Finally, we applied TILP to re-optimize the inferred cell-specific pathways and predict the outcomes of five small compounds (carmustine, doxorubicin, GW-8510, daunorubicin, and verapamil), which were rarely used in clinic for breast cancer. In the simulation, the proposed approach facilitates us to identify a compound's treatment efficacy qualitatively and quantitatively, and the cross validation analysis indicated good accuracy in predicting effects of five compounds.
Conclusions:
In summary, the TILP model is useful for discovering new drugs for clinic use, and also elucidating the potential mechanisms of a compound to targets.
... Myocardial oxidative damage caused by iron-mediated ROS formation has been suggested as a potential mechanism; however, this hypothesis has been challenged by reports showing that several iron chelators failed to reverse cardiotoxic effects of DOX (Miranda et al. 2003;Panjrath et al. 2007;Rao et al. 2011;Šimůnek et al. 2009). ...
Anthracyclines, e.g., doxorubicin (DOX), and anthracenediones, e.g., mitoxantrone (MTX), are drugs used in the chemotherapy of several cancer types, including solid and non-solid malignancies such as breast cancer, leukemia, lymphomas, and sarcomas. Although they are effective in tumor therapy, treatment with these two drugs may lead to side effects such as arrhythmia and heart failure. At the same clinically equivalent dose, MTX causes slightly reduced cardiotoxicity compared with DOX. These drugs interact with iron to generate reactive oxygen species (ROS), target topoisomerase 2 (Top2), and impair mitochondria. These are some of the mechanisms through which these drugs induce late cardiomyopathy. In this review, we compare the cardiotoxicities of these two chemotherapeutic drugs, DOX and MTX. As described here, even though they share similarities in their modes of toxicant action, DOX and MTX seem to differ in a key aspect. DOX is a more redox-interfering drug, while MTX induces energy imbalance. In addition, DOX toxicity can be explained by underlying mechanisms that include targeting of Top2 beta, mitochondrial impairment, and increases in ROS generation. These modes of action have not yet been demonstrated for MTX, and this knowledge gap needs to be filled.
... in acute and chronic models of DOX-induced cardiomyopathy. 19,20 These findings also were extended to human subjects in various clinical trials. 8,17,[21][22][23] It appears that DEX can block adenosine triphosphate (ATP) hydrolysis and inhibit the reopening of the ATPase domain, thereby trapping the topoisomerase complex on DNA and blocking enzyme turnover, 24 which might be its predominant mechanism. ...
Tremendous strides have been made in the treatment of various oncological diseases such that patients are surviving longer and are having better quality of life. However, the success has been tainted by the iatrogenic cardiac toxicities. This is especially concerning in the younger population who are facing cardiac disease such as heart failure in their 30s and 40s as the consequence of the anthracycline’s side-effect (used for childhood leukemia and lymphoma). This resulted in the awareness of cardio-toxic effect of anticancer drugs and emergence of a new discipline: Onco-cardiology. Since then numerous anticancer drugs have been correlated to cardiomyopathy. Additionally, other cardiovascular effects have been identified which includes but no limited to the myocardial infarction, thrombosis, hypertension, arrhythmias and pulmonary hypertension. This review examines some of the anticancer agents mitigating cardio-toxicity and presents current knowledge of molecular mechanism(s). The aim of the review is to ignite awareness of emerging cardio-toxic effects as new generation of anticancer agents are being tested in clinical trials and introduced as part of therapeutic armamentarium to our oncological patients.
... Therefore, the synergistic anti-proliferative combination of Dp44mT with DOX that was observed in the present study may also induce an increased risk of cardiotoxicity. This is of particular relevance considering that Dp44mT has previously shown no effect on inhibiting the cardiotoxic effects of DOX [70]. ...
Recent studies have demonstrated that several chelators possess marked potential as potent anti-neoplastic drugs and as agents that can ameliorate some of the adverse effects associated with standard chemotherapy. Anti-cancer treatment employs combinations of several drugs that have different mechanisms of action. However, data regarding the potential interactions between iron chelators and established chemotherapeutics are lacking. Using estrogen receptor-positive MCF-7 breast cancer cells, we explored the combined anti-proliferative potential of four iron chelators, namely: desferrioxamine (DFO), salicylaldehyde isonicotinoyl hydrazone (SIH), (E)-N'-[1-(2-hydroxy-5-nitrophenyl)ethyliden] isonicotinoyl hydrazone (NHAPI), and di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT), plus six selected anti-neoplastic drugs. These six agents are used for breast cancer treatment and include: paclitaxel, 5-fluorouracil, doxorubicin, methotrexate, tamoxifen and 4-hydroperoxycyclophosphamide (an active metabolite of cyclophosphamide). Our quantitative chelator-drug analyses were designed according to the Chou-Talalay method for drug combination assessment. All combinations of these agents yielded concentration-dependent, anti-proliferative effects. The hydrophilic siderophore, DFO, imposed antagonism when used in combination with all six anti-tumor agents and this antagonistic effect increased with increasing dose. Conversely, synergistic interactions were observed with combinations of the lipophilic chelators, NHAPI or Dp44mT, with doxorubicin and also the combinations of SIH, NHAPI or Dp44mT with tamoxifen. The combination of Dp44mT with anti-neoplastic agents was further enhanced following formation of its redox-active iron and especially copper complexes. The most potent combinations of Dp44mT and NHAPI with tamoxifen were confirmed as synergistic using another estrogen receptor-expressing breast cancer cell line, T47D, but not estrogen receptor-negative MDA-MB-231 cells. Furthermore, the synergy of NHAPI and tamoxifen was confirmed using MCF-7 cells by electrical impedance data, a mitochondrial inner membrane potential assay and cell cycle analyses. This is the first systematic investigation to quantitatively assess interactions between Fe chelators and standard chemotherapies using breast cancer cells. These studies are vital for their future clinical development.
... For example, the xenografted nude mouse is typically used to determine antitumor activity while the spontaneously hypertensive rat (SHR) is the common model for cardiotoxicity studies [10]. The SHR model has demonstrated good correlation between cardiomyopathy induced by anthracyclines and increases in serum levels of cardiac troponin-T, a standard biomarker of cardiotoxicity [11,12]. While the Fisher and Wistar rat models have been applied to the study of tumor reduction and cardiotoxicity previously, the SHR model is uniquely suited for cardiac studies because of the low inter-individual variation, uniform polygenic disposition, and well-characterized biochemical responses to anthracycline toxicity [11,[13][14][15]. ...
... Other portions of the heart were embedded in paraffin, cut into 5 mm sections, and stained with hematoxylin and eosin. Histologically, cardiac sections were scored (0 to 3) for cardiomyopathy (cardiomyocyte cytoplasmic vacuolization and myofibrillar loss) by a board-certified veterinary pathologist using a previously reported scoring system [12,35]. A ranked score approach of the ordinal data obtained from the lesion scores was used. ...
... Doxorubicin in combination with Mito-T (4) induced a significant reduction in body weight in comparison to saline, doxorubicin, or Mito-T (4) alone. Weight loss has been previously observed in response to the parent compound of Mito-T (4), tempol, as well as with doxorubicin [12,42]. No significant differences in the ratio of heart to body weight were observed with the drug treatments (Table S2A). ...
Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC
Doxorubicin is a chemotherapeutic drug that causes oxidative stress-mediated cardiotoxicity. To prevent oxidative stress and help to mitigate the cardiotoxic effects of doxorubicin, the iron chelator dexrazoxane is clinically used. However, iron chelators and other antioxidants have not completely succeeded in mitigating this effect and do not protect against iron-independent oxidative damage. One limitation to the development of new cardioprotectants is the lack of physiologically-relevant animal models to simultaneously study antitumor activity and cardioprotection. Therefore, we optimized a syngeneic rat model and examined the mechanisms by which oxidative stress affects the safety and efficacy outcome. Immune-competent spontaneously hypertensive rats (SHRs) were implanted with the SHR-derived, breast tumor cell line, SST-2. Tumor growth and cytokine responses (IL-1A, MCP-1, TNF-α) were observed two weeks post-implantation. In order to demonstrate the utility of SHR/SST-2 model for monitoring both anticancer efficacy and acute cardiotoxicity, we studied cardiotoxic doxorubicin alone and in combination with dexrazoxane. As predicted, significant tumor reduction, DNA damage, and cardiomyopathy were demonstrated by doxorubicin. Treatment with the cardioprotectant dexrazoxane increased the pro-survival autophagy marker LC3-II and decreased caspase-3 in the heart, as a single agent and in combination with doxorubicin. Histopathology and transmission electron microscopy demonstrated apoptosis, autophagy, and necrosis in tumor and heart. Our results demonstrate the advantage of the immune-proficient SHR/SST-2 model to study anticancer agents and simultaneously address anticancer efficacy and cardiac safety.
Citation Format: Yanira Gonzalez-Berrios, Jennifer S. Dickey, Baikuntha P. Aryal, Elliot T. Rosen, Eugene H. Herman, Steven Mog, Asako J. Nakamura, Christophe E. Redon, Ulrich Baxa, Palak Parekh, Karen P. Mason, William Bonner, Ashutosh Rao. Development and application of a syngeneic breast tumor preclinical model to study anticancer efficacy and cardiac safety of doxorubicin and dexrazoxane. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1386. doi:10.1158/1538-7445.AM2013-1386
... Other portions of the heart were embedded in paraffin, cut into 5 μm sections, and stained with hematoxylin and eosin. Histologically, cardiac sections were scored (0 to 3) for cardiomyopathy (cardiomyocyte cytoplasmic vacuolization and myofibrillar loss) by a board-certified veterinary pathologist using a previously reported scoring system [12], [35]. A ranked score approach of the ordinal data obtained from the lesion scores was used. ...
... Doxorubicin in combination with Mito-T (4) induced a significant reduction in body weight in comparison to saline, doxorubicin, or Mito-T (4) alone. Weight loss has been previously observed in response to the parent compound of Mito-T (4), tempol, as well as with doxorubicin [12], [42]. No significant differences in the ratio of heart to body weight were observed with the drug treatments (Table S2A). ...
... For example, the xenografted nude mouse is typically used to determine antitumor activity while the spontaneously hypertensive rat (SHR) is the common model for cardiotoxicity studies [10]. The SHR model has demonstrated good correlation between cardiomyopathy induced by anthracyclines and increases in serum levels of cardiac troponin-T, a standard biomarker of cardiotoxicity [11], [12]. While the Fisher and Wistar rat models have been applied to the study of tumor reduction and cardiotoxicity previously, the SHR model is uniquely suited for cardiac studies because of the low inter-individual variation, uniform polygenic disposition, and well-characterized biochemical responses to anthracycline toxicity [11], [13]–[15]. ...
Several front-line chemotherapeutics cause mitochondria-derived, oxidative stress-mediated cardiotoxicity. Iron chelators and other antioxidants have not completely succeeded in mitigating this effect. One hindrance to the development of cardioprotectants is the lack of physiologically-relevant animal models to simultaneously study antitumor activity and cardioprotection. Therefore, we optimized a syngeneic rat model and examined the mechanisms by which oxidative stress affects outcome. Immune-competent spontaneously hypertensive rats (SHRs) were implanted with passaged, SHR-derived, breast tumor cell line, SST-2. Tumor growth and cytokine responses (IL-1A, MCP-1, TNF-α) were observed for two weeks post-implantation. To demonstrate the utility of the SHR/SST-2 model for monitoring both anticancer efficacy and cardiotoxicity, we tested cardiotoxic doxorubicin alone and in combination with an established cardioprotectant, dexrazoxane, or a nitroxide conjugated to a triphenylphosphonium cation, Mito-Tempol (4) [Mito-T (4)]. As predicted, tumor reduction and cardiomyopathy were demonstrated by doxorubicin. We confirmed mitochondrial accumulation of Mito-T (4) in tumor and cardiac tissue. Dexrazoxane and Mito-T (4) ameliorated doxorubicin-induced cardiomyopathy without altering the antitumor activity. Both agents increased the pro-survival autophagy marker LC3-II and decreased the apoptosis marker caspase-3 in the heart, independently and in combination with doxorubicin. Histopathology and transmission electron microscopy demonstrated apoptosis, autophagy, and necrosis corresponding to cytotoxicity in the tumor and cardioprotection in the heart. Changes in serum levels of 8-oxo-dG-modified DNA and total protein carbonylation corresponded to cardioprotective activity. Finally, 2D-electrophoresis/mass spectrometry identified specific serum proteins oxidized under cardiotoxic conditions. Our results demonstrate the utility of the SHR/SST-2 model and the potential of mitochondrially-directed agents to mitigate oxidative stress-induced cardiotoxicity. Our findings also emphasize the novel role of specific protein oxidation markers and autophagic mechanisms for cardioprotection.
... Several iron chelators are currently under clinical or pre-clinical development in the treatment of cancer, including breast cancer. Examples of iron chelators with activity in breast cancer include salicylaldehyde isonicotinoyl hydrazone derivatives, 105 Dp44mT, 106,107 and desferri-exochelin. 108 Iron chelators may also provide new insight into iron-dependent pathways in cancer cells. ...
Despite many recent advances, breast cancer remains a clinical challenge. Current issues include improving prognostic evaluation and increasing therapeutic options for women whose tumors are refractory to current frontline therapies. Iron metabolism is frequently disrupted in breast cancer, and may offer an opportunity to address these challenges. Iron enhances breast tumor initiation, growth and metastases. Iron may contribute to breast tumor initiation by promoting redox cycling of estrogen metabolites. Up-regulation of iron import and down-regulation of iron export may enable breast cancer cells to acquire and retain excess iron. Alterations in iron metabolism in macrophages and other cells of the tumor microenvironment may also foster breast tumor growth. Expression of iron metabolic genes in breast tumors is predictive of breast cancer prognosis. Iron chelators and other strategies designed to limit iron may have therapeutic value in breast cancer. The dependence of breast cancer on iron presents rich opportunities for improved prognostic evaluation and therapeutic intervention.
... Therefore, Dp44mT possessed a dose-limiting toxicity that was similar to the clinically used anthracycline, DOX, which is thought to induce cardiotoxicity through the generation of ROS (279). Paradoxically, Dp44mT has been tested as a cardio-protective drug that protects against the cardiac toxicity of DOX (119,237). Both studies demonstrated that Dp44mT was ineffective at attenuating DOX-induced cardiotoxicity (119,237). ...
... Paradoxically, Dp44mT has been tested as a cardio-protective drug that protects against the cardiac toxicity of DOX (119,237). Both studies demonstrated that Dp44mT was ineffective at attenuating DOX-induced cardiotoxicity (119,237). Recently and importantly, Dp44mT was shown to reduce the incidence and growth of metastatic breast cancer cells in a metastasis mouse model without evidence of toxicity (174). ...
Significance:
Under normal circumstances, cellular iron levels are tightly regulated due to the potential toxic effects of this metal ion. There is evidence that tumors possess altered iron homeostasis, which is mediated by the perturbed expression of iron-related proteins, for example, transferrin receptor 1, ferritin and ferroportin 1. The de-regulation of iron homeostasis in cancer cells reveals a particular vulnerability to iron-depletion using iron chelators. In this review, we examine the absorption of iron from the gut; its transport, metabolism, and homeostasis in mammals; and the molecular pathways involved. Additionally, evidence for alterations in iron processing in cancer are described along with the perturbations in other biologically important transition metal ions, for example, copper(II) and zinc(II). These changes can be therapeutically manipulated by the use of novel chelators that have recently been shown to be highly effective in terms of inhibiting tumor growth.
Recent advances:
Such chelators include those of the thiosemicarbazone class that were originally thought to target only ribonucleotide reductase, but are now known to have multiple effects, including the generation of cytotoxic radicals.
Critical issues:
Several chelators have shown marked anti-tumor activity in vivo against a variety of solid tumors. An important aspect is the toxicology and the efficacy of these agents in clinical trials.
Future directions:
As part of the process of the clinical assessment of the new chelators, an extensive toxicological assessment in multiple animal models is essential for designing appropriate dosing protocols in humans.
