Doxorubicin-induced Cardiac Injury Research Articles

Calycosin alleviates ferroptosis and attenuates doxorubicin-induced myocardial injury via the Nrf2/SLC7A11/GPX4 signaling pathway

BackgroundHeart failure is primarily characterized by damage to the structure and function of the heart. Ferroptosis represents a form of programmed cell death, and studies indicate that it constitutes one of the primary mechanisms underlying cardiomyocyte death in heart failure. Calycosin, a natural compound derived from astragalus, exhibits various pharmacological properties, including anti-ferroptosis, antioxidant effects, and cardiovascular protection. Nonetheless, the specific role of Calycosin in the treatment of ferroptosis in heart failure remains poorly understood.ObjectiveThis study aims to elucidate the regulatory effect of Calycosin on ferroptosis and its influence on the treatment mechanisms of heart failure through in vivo and in vitro experiments.MethodsA rat model of heart failure was induced using doxorubicin, and the cardiac function was evaluated through cardiac ultrasound examination and NT-Pro BNP detection. Myocardial injury was assessed using H&E staining and Masson staining. The extent of mitochondrial damage was evaluated through transmission electron microscopy. Concurrently, the level of ferroptosis was analyzed by measuring ferroptosis markers, including MDA, ferrous ions, the GSH/GSSG ratio, and GPX4 activity. Subsequently, the molecular mechanism by which Calycosin exerts its therapeutic effects in heart failure was investigated through immunofluorescence and Western blotting. Finally, H9c2 cardiomyocytes were treated with doxorubicin to simulate myocardial injury, and the mechanism by which Calycosin mediates its effects in the treatment of heart failure was further verified through Nrf2 gene silencing.ResultsCalycosin significantly improves cardiac function in rats, reduces serum NT-Pro BNP levels, and alleviates myocardial cell damage. Additionally, it significantly decreases the levels of ferroptosis in myocardial tissue, as confirmed through transmission electron microscopy and the assessment of ferroptosis markers, including MDA, ferrous ions, GSH, and GPX4 activity. At the molecular level, Calycosin exerts its effects by activating the Nrf2/SLC7A11/GPX4 signaling pathway, evidenced by the upregulation of Nrf2, SLC7A11, GPX4, GSS, and GCL protein expression. This process substantially enhances the antioxidant capacity of rat myocardial tissue and effectively suppresses ferroptosis in myocardial cells. The results obtained from both in vivo and in vitro experiments are consistent. Notably, when Nrf2 is silenced, the protective effect of Calycosin on the myocardium is markedly diminished.ConclusionCalycosin effectively treats doxorubicin-induced cardiac injury, and its therapeutic effect is likely closely associated with the activation of the Nrf2/SLC7A11/GPX4 signaling pathway and the inhibition of ferroptosis in myocardial cells. Consequently, Calycosin, as a promising compound against doxorubicin-induced cardiotoxicity, warrants further investigation.

Novel derivative of nicotinic acid ameliorates doxorubicin-induced cardiac injury via regulation of redox homeostasis

Introduction: Doxorubicin (DOX) is an anthracycline antibiotic with considerable significance in clinics as an anticancer agent, which is limited by its cardiotoxicity, though. A large number of possible therapeutic strategies for reducing cardiotoxicity with doxorubicin have been studied. However, none of them fully meets the requirements of clinical practice. The aim of the study: to evaluate the cardioprotective effects of a new original heterocyclic compound, a pyridine-3-carboxylic acid derivative potassium 5-hydroxynicotinate. Materials and Methods: Cardiac injury was induced by intraperitoneal administration of doxorubicin (DOX) at a dose of 20 mg/kg. After 48 hours, the parameters of left ventricular contractility and StTTI coefficient were assessed on isolated heart in the Langendorff system under the conditions of 480 beats per minute for 11 seconds. Additionally, specific markers of myocardial injury were determined. The lipid peroxidation products and SOD activity were measured as well to challenge whether the compound is able to reduce oxidative stress. Results: The study showed that pretreatment by potassium 5-hydroxynicotinate (35 mg/kg, 48 h) attenuated DOX-induced damage, resulting in a significant decrease in the StТТI coefficient to 3.3 values and in the restoration of the antioxidant activity of enzymes. Conclusion: The obtained data totally demonstrate the protective effects of potassium 5-hydroxynicotinate in DOX-induced cardiomyopathy. A significant role in potassium 5-hydroxynicotinate-mediated cardioprotection is, apparently, related to the reduction of oxidative stress and down-regulation of the level of intracellular calcium.

Cytotoxic T cells drive doxorubicin-induced cardiac fibrosis and systolic dysfunction.

Doxorubicin, the most prescribed chemotherapeutic drug, causes dose-dependent cardiotoxicity and heart failure. However, our understanding of the immune response elicited by doxorubicin is limited. Here we show that an aberrant CD8+ T cell immune response following doxorubicin-induced cardiac injury drives adverse remodeling and cardiomyopathy. Doxorubicin treatment in non-tumor-bearing mice increased circulating and cardiac IFNγ+CD8+ T cells and activated effector CD8+ T cells in lymphoid tissues. Moreover, doxorubicin promoted cardiac CD8+ T cell infiltration and depletion of CD8+ T cells in doxorubicin-treated mice decreased cardiac fibrosis and improved systolic function. Doxorubicin treatment induced ICAM-1 expression by cardiac fibroblasts resulting in enhanced CD8+ T cell adhesion and transformation, contact-dependent CD8+ degranulation and release of granzyme B. Canine lymphoma patients and human patients with hematopoietic malignancies showed increased circulating CD8+ T cells after doxorubicin treatment. In human cancer patients, T cells expressed IFNγ and CXCR3, and plasma levels of the CXCR3 ligands CXCL9 and CXCL10 correlated with decreased systolic function.

AKT2 deficiency alleviates doxorubicin-induced cardiac injury via alleviating oxidative stress in cardiomyocytes

Doxorubicin (DOX), a widely used chemotherapy agent in cancer treatment, encounters limitations in clinical efficacy due to associated cardiotoxicity. This study aims to explore the role of AKT serine/threonine kinase 2 (AKT2) in mitigating DOX-induced oxidative stress within the heart through both intracellular and extracellular signaling pathways. Utilizing Akt2 knockout (KO) and Nrf2 KO murine models, alongside neonatal rat cardiomyocytes (NRCMs), we systematically investigate the impact of AKT2 deficiency on DOX-induced cardiac injury. Our findings reveal that DOX administration induces significant oxidative stress, a primary contributor to cardiac injury. Importantly, Akt2 deficiency exhibits a protective effect by alleviating DOX-induced oxidative stress. Mechanistically, Akt2 deficiency facilitates nuclear translocation of NRF2, thereby suppressing intracellular oxidative stress by promoting the expression of antioxidant genes. Furthermore, We also observed that AKT2 inhibition facilitates superoxide dismutase 2 (SOD2) expression both inside macrophages and SOD2 secretion to the extracellular matrix, which is involved in lowering oxidative stress in cardiomyocytes upon DOX stimulation. The present study underscores the important role of AKT2 in mitigating DOX-induced oxidative stress through both intracellular and extracellular signaling pathways. Additionally, our findings propose promising therapeutic strategies for addressing DOX-induced cardiomyopathy in clinic.

Aging-Associated ALKBH5-m6A Modification Exacerbates Doxorubicin-Induced Cardiomyocyte Apoptosis Via AT-Rich Interaction Domain 2.

Chemotherapy-induced cardiovascular disease is a growing concern in the elderly population who have survived cancer, yet the underlying mechanism remains poorly understood. We investigated the role of ALKBH5 (AlkB homolog 5), a primary N6-methyladenosine (m6A) demethylase, and its involvement in m6A methylation-mediated regulation of targets in aging-associated doxorubicin-induced cardiotoxicity. To validate the relationship between doxorubicin-induced cardiotoxicity and aging, we established young and old male mouse models. ALKBH5 expression was modulated through adeno-associated virus 9 (in vivo), Lentivirus, and siRNAs (in vitro) to examine its impact on cardiomyocyte m6A modification, doxorubicin-induced cardiac dysfunction, and remodeling. We performed mRNA sequencing, methylated RNA immunoprecipitation sequencing, and molecular assays to unravel the mechanism of ALKBH5-m6A modification in doxorubicin-induced cardiotoxicity. Our data revealed an age-dependent increase in doxorubicin-induced cardiac dysfunction, remodeling, and injury. ALKBH5 expression was elevated in aging mouse hearts, leading to reduced global m6A modification levels. Through mRNA sequencing and methylated RNA immunoprecipitation sequencing analyses, we identified ARID2 (AT-rich interaction domain 2) as the downstream effector of ALKBH5-m6A modulation in cardiomyocytes. Further investigations revealed that ARID2 modulates DNA damage response and enhances doxorubicin-induced cardiomyocyte apoptosis. Our findings provide insights into the role of ALKBH5-m6A modification in modulating doxorubicin-induced cardiac dysfunction, remodeling, and cardiomyocyte apoptosis in male mice. These results highlight the potential of ALKBH5-targeted treatments for elderly patients with cancer in clinical settings.

Circulating microRNAs and Cytokines as Prognostic Biomarkers for Doxorubicin-Induced Cardiac Injury and for Evaluating the Effectiveness of an Exercise Intervention.

To define a set of biomarkers that can be used to identify patients at high risk of developing late doxorubicin (DOX)-induced cardiac morbidity with the goal of focused monitoring and early interventions. Mice received phosphate buffered saline or DOX 2.5 mg/kg 2x/week for 2 weeks. Blood samples were obtained before and after therapy for quantification of miRNAs (6 and 24 hours), cytokines (24 hours), and troponin (24 hours, 4 and 6 weeks). Cardiac function was evaluated using echocardiography before and 24 hours after therapy. To assess the effectiveness of exercise intervention in preventing DOX-induced cardiotoxicity blood samples were collected from mice treated with DOX or DOX + exercise. Plasma samples from 13 DOX-treated patients with sarcoma were also evaluated before and 24 hours after therapy. Elevations in plasma miRNA-1, miRNA-499 and IL1α, IL1β, and IL6 were seen in DOX-treated mice with decreased ejection fraction and fractional shortening 24 hours after DOX therapy. Troponin levels were not elevated until 4 weeks after therapy. In mice treated with exercise during DOX, there was no elevation in these biomarkers and no change in cardiac function. Elevations in these biomarkers were seen in 12 of 13 patients with sarcoma treated with DOX. These findings define a potential set of biomarkers to identify and predict patients at risk for developing acute and late cardiovascular diseases with the goal of focused monitoring and early intervention. Further studies are needed to confirm the predictive value of these biomarkers in late cardiotoxicity.

Impact of Disease States on the Oral Pharmacokinetics of EIDD-1931 (an Active Form of Molnupiravir) in Rats for Implication in the Dose Adjustment.

The pharmacokinetic alteration of an antimicrobial medication leading to sub-therapeutic plasma level can aid in the emergence of resistance, a global threat nowadays. In this context, molnupiravir (prodrug of EIDD-1931) is the most efficacious orally against corona virus disease (COVID-19). In addition to drug-drug interaction, the pharmacokinetics of a drug can significantly vary during any disease state, leading to disease-drug interaction. However, no information is available for such a recently approved drug. Therefore, we aimed to explore the oral pharmacokinetics of EIDD-1931 in seven chemically induced disease states individually compared to the normal state using various rat models. Induction of any disease situation was confirmed by the disease specific study(s) prior to pharmacokinetic investigations. Compared to the normal state, substantially lowered plasma exposure (0.47- and 0.63-fold) with notably enhanced clearance (2.00- and 1.56-fold) of EIDD-1931 was observed in rats of ethanol-induced gastric injury and carbon tetrachloride-induced liver injury states. Conversely, paclitaxel-induced neuropathic pain and cisplatin-induced kidney injury states exhibited opposite outcomes on oral exposure (1.43- and 1.50-fold) and clearance (0.69- and 0.65-fold) of EIDD-1931. Although the highest plasma concentration (2.26-fold) markedly augmented in the doxorubicin-induced cardiac injury state, streptozocin-induced diabetes and lipopolysaccharide-induced lung injury state did not substantially influence the pharmacokinetics of EIDD-1931. Exploring the possible phenomenon behind the reduced or boosted plasma exposure of EIDD-1931, results suggest the need for dose adjustment in respective diseased conditions in order to achieve desired efficacy during oral therapy of EIDD-1931.

Sodium acetate ameliorates doxorubicin-induced cardiac injury via upregulation of Nrf2/HO-1 signaling and downregulation of NFkB-mediated apoptotic signaling in Wistar rats.

Despite the effectiveness of doxorubicin (DOX) in the management of a wide range of cancers, a major challenge is its cardio-toxic effect. Oxidative stress, inflammation, and apoptosis are major pathways for the cardiotoxic effect of DOX. On the other hand, acetate reportedly exerts antioxidant, anti-inflammatory, and anti-apoptotic activities. This particular research assessed the impact of acetate on cardiotoxicity induced by DOX. Mechanistically, acetate dramatically inhibited DOX-induced upregulation of xanthine oxidase and uric acid pathway as well as downregulation of Nrf2/HO-1 signaling and its upstream proteins (reduced glutathione peroxidase, superoxide dismutase, glutathione-S-transferase, glutathione, and catalase, glutathione reductase). In addition, acetate markedly attenuated DOX-driven rise inTNF-α, NFkB IL-6 and IL-1β expression, and myeloperoxidase activity. Furthermore, acetate significantly ameliorated DOX-led suppression of Bcl-2 and Ca2+-ATPase activity and upregulation of Bax, caspase 3, and caspase 9 actions. Improved body weight, heart structural integrity, and cardiac function as depicted by cardiac injury markers convoyed these cascades of events. Summarily, the present study demonstrated that acetate protects against DOX-induced cardiotoxicity by upregulating Nrf2/HO-1 signaling and downregulating NFkB-mediated activation of Bax/Bcl-2 and caspase signaling.

Hydrogen inhalation enhances autophagy via the AMPK/mTOR pathway, thereby attenuating doxorubicin-induced cardiac injury.

Doxorubicin is a drug widely used in clinical cancer treatment, but severe cardiotoxicity limits its clinical application. Autophagy disorder is an important factor in the mechanism of doxorubicin-induced cardiac injury. As the smallest molecule in nature, hydrogen has various biological effects such as anti-oxidation, anti-apoptosis and regulation of autophagy. Hydrogen therapy is currently considered to be an emerging therapeutic method, but the effect and mechanism of hydrogen on doxorubicin-induced myocardial injury have not been determined. The purpose of this study was to investigate the protective effect of hydrogen inhalation on doxorubicin-induced chronic myocardial injury and its effect and mechanism on autophagy. In this study, we established a chronic heart injury model by intraperitoneal injection of doxorubicin in rats for 30days, accumulating 20mg/kg. The effect of hydrogen inhalation on the cardiac function in rats was explored by echocardiography, Elisa, and H&E staining. To clarify the influence of autophagy, we detected the expression of LC3 and related autophagy proteins in vivo and in vitro by immunofluorescence and western blot.In order to further explore the mechanism of autophagy, we added pathway inhibitors and used western blot to preliminarily investigate the protective effect of hydrogen inhalation on myocardial injury caused by doxorubicin. Hydrogen inhalation can improve doxorubicin-induced cardiac function decline and pathological structural abnormalities in rats. It was confirmed by immunofluorescence that hydrogen treatment could restore the expression of autophagy marker protein LC3 (microtubule-associated protein 1 light chain 3) in cardiomyocytes reduced by doxorubicin, while reducing cardiomyocyte apoptosis. Mechanistically, Western blot results consistently showed that hydrogen treatment up-regulated the ratio of p-AMPK (phosphorylated AMP-dependent protein kinase) to AMPK and down-regulated p-mTOR (phosphorylated mammalian target of rapamycin) and mTOR ratio. These results suggest that hydrogen inhalation can activate autophagy through the AMPK/mTOR pathway and protect against myocardial injury induced by doxorubicin. Hydrogen inhalation therapy may be a potential treatment for doxorubicin-induced myocardial injury.

Thrombin-mediated activation of PAR1 enhances doxorubicin-induced cardiac injury in mice.

The chemotherapeutic drug doxorubicin is cardiotoxic and can cause irreversible heart failure. In addition to being cardiotoxic, doxorubicin also induces the activation of coagulation. We determined the effect of thrombin-mediated activation of protease-activated receptor 1 (PAR1) on doxorubicin-induced cardiac injury. Administration of doxorubicin to mice resulted in a significant increase in plasma prothrombin fragment 1+2, thrombin-antithrombin complexes, and extracellular vesicle tissue factor activity. Doxorubicin-treated mice expressing low levels of tissue factor, but not factor XII-deficient mice, had reduced plasma thrombin-antithrombin complexes compared to controls. To evaluate the role of thrombin-mediated activation of PAR1, transgenic mice insensitive to thrombin (Par1R41Q) or activated protein C (Par1R46Q) were subjected to acute and chronic models of doxorubicin-induced cardiac injury and compared with Par1 wild-type (Par1+/+) and PAR1 deficient (Par1-/-) mice. Par1R41Q and Par1-/- mice, but not Par1R46Q mice, demonstrated similar reductions in the cardiac injury marker cardiac troponin I, preserved cardiac function, and reduced cardiac fibrosis compared to Par1+/+ controls after administration of doxorubicin. Furthermore, inhibition of Gαq signaling downstream of PAR1 with the small molecule inhibitor Q94 significantly preserved cardiac function in Par1+/+ mice, but not in Par1R41Q mice subjected to the acute model of cardiac injury when compared to vehicle controls. In addition, mice with PAR1 deleted in either cardiomyocytes or cardiac fibroblasts demonstrated reduced cardiac injury compared to controls. Taken together, these data suggest that thrombin-mediated activation of PAR1 contributes to doxorubicin-induced cardiac injury.

Cardiac sirtuin1 deficiency exacerbates ferroptosis in doxorubicin-induced cardiac injury through the Nrf2/Keap1 pathway

Doxorubicin (DOX), a broad-spectrum chemotherapeutic agent for various cancers, has limited clinical application because of its serious cardiotoxicity, which is due to different mechanisms, including cardiac ferroptosis and oxidative stress. Some drugs, such as berberine or dioscin, show efficacy in impeding DOX-induced cardiotoxicity by activating Sirtuin 1 (Sirt1). However, there is no direct evidence to clarify the role of Sirt1 in DOX-induced cardiomyopathy and its underlying role in cardiac ferroptosis. In this study, C57BL/6 and cardiac-specific Sirt1−/− knockout mice were used as a DOX-induced cardiotoxicity model. We found that cardiac Sirt1 was downregulated, oxidative stress was increased and ferroptosis were obviously enhanced, as reflected by decreased Glutathione peroxidase 4 (GPX4) and increased Heme oxygenase 1 (Hmox-1), exposure to DOX treatment in mice and H9c2 cells compared with the control. And Sirt1 activation was resistant to cardiac injury induced by DOX, as observed the improvement of cardiac dysfunction, and the reduction of cardiac fibrosis. However, cardiac Sirt1 deficiency aggravated Dox-induced cardiac dysfunction and cardiac remodeling, further downregulated GPX4, upregulated Hmox-1 expression and increased ROS level. In addition, Sirt1-siRNA exacerbated DOX-induced cardiotoxicity in H9c2 cells, which is similar to the results obtained in vivo. Furthermore, DOX decrease Nrf2 translocation from the cytosol to the nucleus, and Sirt1 deficiency further restrain the process, as well as the downstream Keap1 pathways, in DOX-induced cardiotoxicity. This study provides direct evidence that Sirt1 plays a protective role in DOX-induced cardiotoxicity by mediating ferroptosis reduction via the Nrf2/Keap1 pathway.

Melatonin alleviates doxorubicin-induced cardiotoxicity via inhibiting oxidative stress, pyroptosis and apoptosis by activating Sirt1/Nrf2 pathway

Melatonin confers cardioprotective effects on multiple cardiovascular diseases, including doxorubicin-induced cardiomyopathy. The effectiveness of melatonin in mitigating myocardial injuries caused by Doxorubicin through enhancement of mitochondrial function is already established, however, the role of melatonin in regulating the Sirtuin-1 (Sirt1)/Nuclear factor E2-associated factor 2 (Nrf2) pathway in lessening the onset of Doxorubicin-induced cardiomyopathy is yet to be elucidated. To address this, H9C2 cardiomyocytes and C57BL/6 mice were employed to construct in vitro and in vivo models of Dox-induced myocardial impairments, respectively. Results showed that Dox markedly evoked oxidative stress, pyroptosis and apoptosis both in vitro and in vivo, which were significantly alleviated by melatonin administration. Mechanistically, melatonin attenuated Dox-induced downregulation of Sirt1 and Nrf2, and both inhibition of Sirt1 and Nrf2 significantly reversed the cardioprotective effects of melatonin. In conclusion, our studies suggest that the activation of the Sirt1/Nrf2 pathway is the underlying mechanism behind melatonin's ability to curtail oxidative stress, pyroptosis, and apoptosis in Dox-induced cardiomyopathy. These promising results demonstrated the potential application of melatonin as a treatment for doxorubicin-induced cardiac injury.

Columbianadin attenuates doxorubicin-induced cardiac injury, oxidative stress, and apoptosis via Sirt1/FOXO1 signaling pathway.

Oxidative stress and apoptosis contribute to the pathological basis of doxorubicin (DOX)-induced cardiotoxicity. Columbianadin (CBN) is one of the main bioactive constituents isolated from the root of Angelica pubescens. Herein, we intended to explore the potential role and molecular basis of CBN in DOX-induced cardiotoxicity. C57BL/6 mice were subjected to DOX (15 mg/kg/day, i.p.) to generate DOX-induced cardiotoxicity. CBN (10 mg/kg/day, i.p.) was administered for four week following DOX injection. DOX administered markedly dampened cardiac function, increased cardiac injury, excessive reactive oxygen species (ROS) production, and cardiomyocyte loss. These alterations induced by DOX significantly alleviated by CBN treatment. Mechanistically, our results demonstrated that the CBN exerts cardioprotection role against DOX by up-regulating silent information regulator 1 (Sirt1) and decreasing acetylation of forkhead box O1 (FOXO1). Moreover, Sirt1 inhibition with Ex-527 significantly blunt the beneficial effect of CBN on DOX-induced cardiotoxicity, including cardiac dysfunction, ROS, and apoptosis. Collectively, CBN attenuated oxidative stress and cardiomyocyte apoptosis in DOX-induced cardiotoxicity through maintaining Sirt1/FOXO1 signaling pathway. Our results demonstrated that CBN might be used to treat DOX-related cardiotoxicity.

Daidzein ameliorates doxorubicin-induced cardiac injury by inhibiting autophagy and apoptosis in rats.

Backgrounds: Doxorubicin (Dox) is a classical antitumor antibiotic widely restricted for use due to its cardiotoxicity. Daidzein (Daid) is a soy isoflavone that enhances antioxidant enzyme systems and inhibits apoptosis to prevent cardiovascular diseases. In this study, we intended to assess whether Daid protects against Dox-induced cardiotoxicity and explored its underlying mechanisms. Methods: Male Sprague-Dawley (SD) rats were divided into five groups: control (Ctrl), 40 mg per kg per day Daidzein (Daid), 3 mg per kg per week doxorubicin (Dox), 20 mg per kg per day Daidzein + 3 mg per kg per week doxorubicin (Daid20 + Dox) and 40 mg per kg per day Daidzein + 3 mg per kg per week doxorubicin (Daid40 + Dox) groups. Cardiac function assessments, immunohistochemistry (IHC) and immunofluorescence (IF) analyses were initially performed in each group of rats. Secondly, the cell proliferative capacity analysis, AO staining, and LC3 puncta analysis were employed to evaluate the cellular response to Dox in H9c2 cells. Ultimately, the protein expressions of cleaved caspase3, LC3 II, Bcl-2, Bax, Akt, p-Akt, and cyclin D1 were examined by western blotting. Results: Pretreatment with a low dose of Daid rather than a high dose significantly enhanced cardiac function and alleviated histopathological deterioration of cardiomyocytes induced by Dox. Daid downregulated the protein levels of Bax, LC3 II, cleaved caspase3 and p-Akt, while up-regulating Bcl-2 and cyclin D1. The Akt agonist SC79 could invalidate all the protective effects of Daid both in vivo and in vitro. Conclusions: Daid reduced autophagy and apoptosis by inhibiting the PI3K/Akt pathway, thereby protecting the hearts from Dox-induced cardiac damage.

Antiresistin Neutralizing Antibody Alleviates Doxorubicin-Induced Cardiac Injury in Mice.

Resistin is closely related to cardiovascular diseases, and this study is aimed at examining the role of resistin in doxorubicin- (DOX-) induced cardiac injury. First, 48 mice were divided into 2 groups and treated with saline or DOX, and the expression of resistin at different time points was examined (N = 24). A total of 40 mice were pretreated with the antiresistin neutralizing antibody (nAb) or isotype IgG for 1 hour and further administered DOX or saline for 5 days. The mice were divided into 4 groups: saline-IgG, saline-nAb, DOX-IgG, and DOX-nAb (N = 10). Cardiac injury, cardiomyocyte apoptosis, inflammatory factors, and the biomarkers of M1 and M2 macrophages in each group were analyzed. DOX administration increased the expression of resistin. DOX treatment exacerbated the loss of body and heart weight and cardiac vacuolation in mice. The antiresistin nAb reversed these conditions, downregulated the expression of myocardial injury markers, and decreased apoptosis. In addition, the antiresistin nAb decreased p65 pathway activation, decreased M1 macrophage differentiation and the expression of related inflammatory factors, and increased M2 macrophage differentiation and the expression of related inflammatory factors. The antiresistin nAb protected against DOX-induced cardiac injury by reducing cardiac inflammation and may be a promising target to relieve DOX-related cardiac injury.

Bone morphogenetic protein 10 alleviates doxorubicin-induced cardiac injury via signal transducer and activator of transcription 3 signaling pathway

ABSTRACT Doxorubicin (DOX) has limited antitumor applications owing to its association with life-threatening cardiac injury. Oxidative damage and cardiac apoptosis are crucial in DOX-induced cardiac injury. Bone morphogenetic protein 10 (BMP10) is predominantly distributed in the heart and acts as a cardioprotective factor that preserves cardiac function. However, the role of BMP10 in DOX-induced cardiac injury has not yet been explored. The current study aimed to examine the function and mechanism of action of BMP10 in DOX-induced cardiac injury. An adeno-associated viral system was used for the overexpression or silencing of cardiac-specific BMP10, and subsequently, a single dose of DOX was intraperitoneally injected to induce cardiac injury. Results showed that DOX exposure decreased BMP10 expression in the heart. Cardiac-specific overexpression of BMP10 alleviated the oxidative stress and apoptosis and improved cardiac function. Conversely, cardiac-specific silencing of BMP10 aggravated the redox disorder and apoptosis and worsened the cardiac dysfunction caused by DOX. Exogenous BMP10 supplementation amelioratesd the DOX-induced cardiac contractile dysfunction. Mechanistically, we found that phosphorylation of signal transducer and activator of transcription 3 (STAT3) is reduced in DOX-induced cardiotoxicity, and, BMP10 activated impaired STAT3 via a non-canonical pathway. BMP10 lost its cardioprotective function in cardiomyocyte-specific STAT3 knockout (STAT3-cKO) mice. Based on our findings, we suggested that BMP10 is a potential therapeutic agent against DOX-induced cardiac injury and that the cardioprotective effects of BMP10 are dependent on the activation of STAT3.

Sex differences in cardio-oncology: utilizing a genetic variant as a therapeutic target doxorubicin-induced cardiomyopathy

Abstract Introduction Doxorubicin is an anthracycline used as a chemotherapeutic drug for the treatment of a wide range of adult and pediatric cancers. Doxorubicin is associated with an increased risk of cardiomyopathy and heart failure with up to 10% of patients developing cardiac complications. A GWAS conducted of 1,191 patients from the N9831 clinical trial identified that cardiac gene expression and genetic variants of TRPC6 were associated with a decline in left ventricular ejection fraction (LVEF) (p=0.005 and p=1.6x10–6, respectively). TRPC6 is a non-selective cation channel expressed in heart and vascular tissue. TRPC6 participates in the pathogenesis of cardiac hypertrophy as a pathological response to chronic mechanical stress. Chronic activation has been found to promote cardiac fibrosis leading to heart failure. Purpose TRPC6 variants could be associated with increased risk of doxorubicin-induced cardiotoxicity. Data/tests to determine which patients may progress to cardiomyopathy and heart failure are currently lacking and there are no targeted treatments to prevent cardiomyopathy in these patients. Methods In preliminary in vivo data, B6.129 wild-type mice or TRPC6 knockout mice were treated with either 6x intraperitoneal saline or 4mg/kg doxorubicin injections (cumulative dose of 24mg/kg). Results We found doxorubicin increased cardiac vacuolation (male, p≤0.001 and female, p≤0.05) in WT mice compared to controls. Higher HW/BW ratio was observed in male TRPC6 knock out mice compared to wild-type mice when both were treated with doxorubicin (males, p=0.005 and females, p=0.19). Additionally, we found that doxorubicin-induced cardiac injury was significantly reduced in TRPC6 knock-out mice compared to wild-type mice based on reduced vacuolation (p=0.0004 males, p=0.03 females), with the effect being greater in male mice than female mice. Furthermore, a significant decrease in stroke volume (p=0.007), diastolic volume (p=0.01) and cardiac output (p=0.004) in wild-type male mice treated with doxorubicin compared to control and TRPC6 knock-out mice. Our in vitro preliminary data show that inhibition of TRPC6 using the TRPC6 inhibitor GsMTx-4 in human iPSC-derived cardiomyocytes significantly reduced doxorubicin-induced apoptosis (p<0.0001). Further we treated male mice with the TRPC6 inhibitor, GsMTx4, and found that they had less global longitudinal cardiac strain (p=0.04) and higher ejection fraction (p=0.01) compared to mice who were only treated with doxorubicin. Histologically we found that mice given the TRPC6 inhibitor had less fibrosis as measured by Trichrome stained heart sections (p=0.004) which could account for improvements in cardiac function. Conclusion TRPC6 could be a novel therapeutic target in the prevention of chemotherapy-induced cardiomyopathy and heart failure. Additionally genetic mapping of TRCP6 functional variants may provide a new screening tool to determine increased risk of developing heart failure. Funding Acknowledgement Type of funding sources: Private hospital(s). Main funding source(s): Mayo Clinic

Abstract 2378: Circulating microRNAs and cytokines as prognostic biomarkers for doxorubicin-induced cardiac injury and for evaluating the beneficial effects of exercise

Abstract Introduction: Cardiotoxicity and late cardiomyopathies compromise survival in >50% of childhood cancer survivors treated doxorubicin (Dox). Early intervention is important for initiating therapy to preserve heart function. There are no accepted biomarkers identifying which patients are at risk for developing cardiac problems and no interventions to inhibit the cardiac damage. Troponin has not proved useful for predicting Dox-induced cardiotoxicity and patient outcome. We developed a pediatric mouse cardiotoxicity model to define early biomarkers of Dox-induced cardiac injury, investigate the efficacy of an exercise intervention, and whether these biomarkers can be used as a non-invasive method to monitor exercise effectiveness. Hypothesis: Circulating micro-RNAs are increased during Dox but not Dox + exercise therapy which correlate with cardiac damage. These can be used to monitor intervention effectiveness. Methods: Mice were treat with Dox (2.5mg/kg 2x/wk for 2 wks), Dox + exercise (walking 45 min/day at 12 meter/min) or PBS. Cardiac function was evaluated by echocardiography 24 hrs after therapy. Blood was collect before and 6 and 24 hrs after therapy. Plasma cytokine levels, troponin and miRNAs (miRNA 1, 29b, 499) were quantified. We also obtained plasma samples from Dox-treated osteosarcoma patients. Results: Decreased ejection fraction and fractional shortening were seen in Dox but not Dox + exercise-treated mice. There was an increase in miR-1 and miR-499 and the pro-inflammatory cytokines IL-1α, IL-1β and IL-6, in Dox-treated but not Dox + exercise-treated mice compared with PBS controls. Troponin levels were not elevated until 24 hrs following therapy. Increased miRNAs and cytokines in the Dox-treated patient plasma samples 24 hrs after therapy mimicked the results observed in mice. Conclusion: These data indicate that miRNA499, miRNA1, IL-1α, IL-1β and IL-6 are early biomarkers of Dox-induced cardiac injury which predict cardiac functional changes and can be used to evaluate intervention efficacy during combined therapy. Following these biomarkers may also assist in identifying patients at risk for cardiac late effects and also enable intervention modification as needed. Citation Format: Prince Jeyabal, Eugenie S. Kleinerman. Circulating microRNAs and cytokines as prognostic biomarkers for doxorubicin-induced cardiac injury and for evaluating the beneficial effects of exercise [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2378.

Dopamine D1 receptor alleviates doxorubicin-induced cardiac injury by inhibiting NLRP3 inflammasome

Doxorubicin (DOX) is a broad-spectrum antineoplastic drug; however, its serious cardiotoxic side effects in inflammatory responses limit its use in clinical applications. Dopamine D1 receptor (DRD1), a G protein-coupled receptor, is crucial for the development and function of the nervous system; additionally, it also play a role in immune regulation. However, the specific role of DRD1 in DOX-induced cardiac inflammation has not yet been clarified. Here, we discovered that DRD1 expression was induced by DOX treatment in H9C2 cardiomyocytes. DRD1 activation by A-68930, a DRD1-specific agonist, decreased DOX-induced nucleotide-binding domain-like receptor protein 3 (NLRP3) expression, caspase-1 activation, and IL-1β maturation in H9C2 cells. Expression of the cytokines IL-1β and IL-18 in the supernatants was also inhibited by A-68930 treatment. DRD1 knockdown, using siRNA, abolished the effects of A-68930 on the DOX-induced NLRP3 inflammasome. Furthermore, we found that DRD1 signaling downregulated the NLRP3 inflammasome in H9C2 cells through cyclic adenosine monophosphate (cAMP). Moreover, application of A-68930 to activate DRD1 reduced cardiac injury and fibrosis in a DOX-treated mouse model by suppressing the NLRP3 inflammasome in the heart. These findings indicate that DRD1 signaling may protect against DOX-induced cardiac injury by inhibiting the NLRP3 inflammasome-mediated inflammation.

Structurally diverse alkaloids from Buxus sempervirens with cardioprotective activity

Extensive phytochemical study of the methanol extract of twigs and leaves of Buxus sempervirens resulted in the identification of 17 Buxus alkaloids, including 12 new ones, namely buxusemines A–L (1–12). Their structures were delineated by detailed analysis of the HRESIMS and NMR data, as well as quantum chemical NMR calculations. Buxusemine A (1) represents the second Buxus alkaloid with a unique spiro[4.6]undecatriene moiety, buxusemines B–C (2–3) are a rarely occurring class of Buxus alkaloids featured with an additional five-membered ring through the ether or lactone linkage between C-10 and C-23, and buxusemines D–F (4–6) are another rare type of Buxus alkaloids with an epoxy motif. In the assessment of their bioactivities, buxusemine F (6) and buxanoldine (17) displayed more potent protective effects than the positive control cyclovirobuxinum D in the doxorubicin-induced cardiac injury model.