Disruption of nitric oxide synthase 3 protects against the cardiac injury, dysfunction, and mortality induced by doxorubicin

Functional Validation of Doxorubicin-Induced Cardiotoxicity-Related Genes

Background

Genome-wide association studies and candidate gene association studies have identified more than 180 genetic variants statistically associated with anthracycline-induced cardiotoxicity (AIC). However, the lack of functional validation has hindered the clinical translation of these findings.

Objectives

The aim of this study was to functionally validate all genes associated with AIC using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs).

Methods

Through a systemic literature search, 80 genes containing variants significantly associated with AIC were identified. Additionally, 3 more genes with potential roles in AIC (GSTM1, CBR1, and ERBB2) were included. Of these, 38 genes exhibited expression in human fetal heart, adult heart, and hiPSC-CMs. Using clustered regularly interspaced short palindromic repeats/Cas9-based genome editing, each of these 38 genes was systematically knocked out in control hiPSC-CMs, and the resulting doxorubicin-induced cardiotoxicity (DIC) phenotype was assessed using hiPSC-CMs. Subsequently, functional assays were conducted for each gene knockout on the basis of hypothesized mechanistic implications in DIC.

Results

Knockout of 26 genes increased the susceptibility of hiPSC-CMs to DIC. Notable genes included efflux transporters (ABCC10, ABCC2, ABCB4, ABCC5, and ABCC9), well-established DIC-associated genes (CBR1, CBR3, and RAC2), and genome-wide association study-discovered genes (RARG and CELF4). Conversely, knockout of ATP2B1, HNMT, POR, CYBA, WDR4, and COL1A2 had no significant effect on the in vitro DIC phenotype of hiPSC-CMs. Furthermore, knockout of the uptake transporters (SLC28A3, SLC22A17, and SLC28A1) demonstrated a protective effect against DIC.

Conclusions

The present findings establish a comprehensive platform for the functional validation of DIC-associated genes, providing insights for future studies in DIC variant associations and potential mechanistic targets for the development of cardioprotective drugs.

Anthracycline Toxicity: Light at the End of the Tunnel?

Anthracycline-induced cardiotoxicity (AIC) is a serious and common side effect of anthracycline therapy. Identification of genes and genetic variants associated with AIC risk has clinical potential as a cardiotoxicity predictive tool and to allow the development of personalized therapies. In this review, we provide an overview of the function of known AIC genes identified by association studies and categorize them based on their mechanistic implication in AIC. We also discuss the importance of functional validation of AIC-associated variants in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) to advance the implementation of genetic predictive biomarkers. Finally, we review how patient-specific hiPSC-CMs can be used to identify novel patient-relevant functional targets and for the discovery of cardioprotectant drugs to prevent AIC. Implementation of functional validation and use of hiPSC-CMs for drug discovery will identify the next generation of highly effective and personalized cardioprotectants and accelerate the inclusion of approved AIC biomarkers into clinical practice.

Network Pharmacology along with Molecular Docking to Explore the Mechanism of Danshen Injection against Anthracycline-induced Cardiotoxicity and Transcriptome Validation

INTRODUCTION

Although anthracyclines have demonstrated efficacy in cancer therapy, their utilization is constrained by cardiotoxicity. In contrast, Danshen injection (DSI), derived from Salvia miltiorrhiza, has a longstanding tradition of being employed to ameliorate cardiovascular ailments, including anthracycline- induced cardiotoxicity (AIC). Nonetheless, there is a notable dearth of comprehensive systematic investigation into the molecular mechanisms underlying DSI's effects on AIC. Consequently, this study was undertaken to explore the underlying mechanism by which DSI acted against AIC.

METHODS

Employing network pharmacology approach, the current investigation undertook a comprehensive analysis of the impact of DSI on AIC, which was further validated by transcriptome sequencing with in vitro AIC model. Additionally, molecular docking was conducted to evaluate the binding of active ingredients to core targets. A total of 3,404 AIC-related targets and 12 active ingredients in DSI, including chrysophanol, luteolin, tanshinone IIA, isoimperatorin, among others, were collected by differentially expressed analysis and database search, respectively.

RESULTS

The network pharmacology and enrichment analysis suggested 102 potential targets and 29 signaling pathways associated with the protective effect of DSI on AIC. Three core targets (CA12, NOS3, and POLH) and calcium signaling pathways were further validated by transcriptomic analysis of the in-vitro model. The high affinity of the active ingredients binding to corresponding targets was confirmed by molecular docking.

CONCLUSION

The present study suggested that DSI might exert a cardioprotective effect on AIC via the inhibition of CA12, NOS3, and POLH, as well as the modulation of calcium signaling. Further experiments are warranted to verify the findings.

Anthracycline-induced cardiotoxicity: mechanisms, monitoring, and prevention

Anthracyclines are the most fundamental and important treatment of several cancers especially for lymphoma and breast cancer. However, their use is limited by a dose-dependent cardiotoxicity which may emerge early at the initiation of anthracycline administration or several years after termination of the therapy. A full comprehending of the mechanisms of anthracycline-induced cardiotoxicity, which has not been achieved and is currently under the efforts, is critical to the advance of developing effective methods to protect against the cardiotoxicity, as well as to early detect and treat it. Therefore, we review the recent progress of the mechanism underlying anthracycline-induced cardiotoxicity, as well as approaches to monitor and prevent this issue.

Myeloperoxidase is a critical mediator of anthracycline-induced cardiomyopathy

Cardiotoxicity is a major complication of anthracycline therapy that negatively impacts prognosis. Effective pharmacotherapies for prevention of anthracycline-induced cardiomyopathy (AICM) are currently lacking. Increased plasma levels of the neutrophil-derived enzyme myeloperoxidase (MPO) predict occurrence of AICM in humans. We hypothesized that MPO release causally contributes to AICM. Mice intravenously injected with the anthracycline doxorubicin (DOX) exhibited higher neutrophil counts and MPO levels in the circulation and cardiac tissue compared to saline (NaCl)-treated controls. Neutrophil-like HL-60 cells exhibited increased MPO release upon exposition to DOX. DOX induced extensive nitrosative stress in cardiac tissue alongside with increased carbonylation of sarcomeric proteins in wildtype but not in Mpo-/- mice. Accordingly, co-treatment of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) with DOX and MPO aggravated loss of hiPSC-CM-contractility compared to DOX treatment alone. DOX-treated animals exhibited pronounced cardiac apoptosis and inflammation, which was attenuated in MPO-deficient animals. Finally, genetic MPO deficiency and pharmacological MPO inhibition protected mice from the development of AICM. The anticancer efficacy of DOX was unaffected by MPO deficiency. Herein we identify MPO as a critical mediator of AICM. We demonstrate that DOX induces cardiac neutrophil infiltration and release of MPO, which directly impairs cardiac contractility through promoting oxidation of sarcomeric proteins, cardiac inflammation and cardiomyocyte apoptosis. MPO thus emerges as a promising pharmacological target for prevention of AICM.

IFN-γ-STAT1-ERK Pathway Mediates Protective Effects of Invariant Natural Killer T Cells Against Doxorubicin-Induced Cardiomyocyte Death

Doxorubicin (DOX)-induced cardiomyopathy has poor prognosis, and myocardial inflammation is intimately involved in its pathophysiology. The role of invariant natural killer T (iNKT) cells has not been fully determined in this disease. We here demonstrated that activation of iNKT cells by α-galactosylceramide (GC) attenuated DOX-induced cardiomyocyte death and cardiac dysfunction. αGC increased interferon (IFN)-γ and phosphorylation of signal transducers and activators of transcription 1 (STAT1) and extracellular signal-regulated kinase (ERK). Administration of anti-IFN-γ neutralizing antibody abrogated the beneficial effects of αGC on DOX-induced cardiac dysfunction. These findings emphasize the protective role of iNKT cells in DOX-induced cardiomyopathy via the IFN-γ-STAT1-ERK pathway.

Modeling Cardiotoxicity in Pediatric Oncology Patients Using Patient-Specific iPSC-Derived Cardiomyocytes Reveals Downregulation of Cardioprotective microRNAs

Anthracyclines are widely used in the treatment of many solid cancers, but their efficacy is limited by cardiotoxicity. As the number of pediatric cancer survivors continues to rise, there has been a concomitant increase in people living with anthracycline-induced cardiotoxicity. Accordingly, there is an ongoing need for new models to better understand the pathophysiological mechanisms of anthracycline-induced cardiac damage. Here we generated induced pluripotent stem cells (iPSCs) from two pediatric oncology patients with acute cardiotoxicity induced by anthracyclines and differentiated them to ventricular cardiomyocytes (hiPSC-CMs). Comparative analysis of these cells (CTX hiPSC-CMs) and control hiPSC-CMs revealed that the former were significantly more sensitive to cell injury and death from the anthracycline doxorubicin (DOX), as measured by viability analysis, cleaved caspase 3 expression, oxidative stress, genomic and mitochondrial damage and sarcomeric disorganization. The expression of several mRNAs involved in structural integrity and inflammatory response were also differentially affected by DOX. Functionally, optical mapping analysis revealed higher arrythmia complexity after DOX treatment in CTX iPSC-CMs. Finally, using a panel of previously identified microRNAs associated with cardioprotection, we identified lower levels of miR-22-3p, miR-30b-5p, miR-90b-3p and miR-4732-3p in CTX iPSC-CMs under basal conditions. Our study provides valuable phenotype information for cellular models of cardiotoxicity and highlights the significance of using patient-derived cardiomyocytes for studying the associated pathogenic mechanisms.

Role of oxidative stress and inflammation-related signaling pathways in doxorubicin-induced cardiomyopathy

Doxorubicin (DOX) is a powerful and commonly used chemotherapeutic drug, used alone or in combination in a variety of cancers, while it has been found to cause serious cardiac side effects in clinical application. More and more researchers are trying to explore the molecular mechanisms of DOX-induced cardiomyopathy (DIC), in which oxidative stress and inflammation are considered to play a significant role. This review summarizes signaling pathways related to oxidative stress and inflammation in DIC and compounds that exert cardioprotective effects by acting on relevant signaling pathways, including the role of Nrf2/Keap1/ARE, Sirt1/p66Shc, Sirt1/PPAR/PGC-1α signaling pathways and NOS, NOX, Fe²⁺ signaling in oxidative stress, as well as the role of NLRP3/caspase-1/GSDMD, HMGB1/TLR4/MAPKs/NF-κB, mTOR/TFEB/NF-κB pathways in DOX-induced inflammation. Hence, we attempt to explain the mechanisms of DIC in terms of oxidative stress and inflammation, and to provide a theoretical basis or new idea for further drug research on reducing DIC. Video Abstract.

Fluvastatin alleviates doxorubicin-induced cardiac and renal toxicity in rats via regulation of oxidative stress, inflammation, and apoptosis associated genes expressions

Doxorubicin (DOXO) is a cytostatic agent used in the chemotherapy protocol of several cancers for more than 40 years, but usage of this drug in cancer treatment has been limited due to severe renal and cardiac tissue toxicities that may result in death in patients. Fluvastatin (FV) is a fully synthetic hydroxymethyl glutaryl coenzyme A (HMG-CoA) reductase inhibitor used as a cholesterol-lowering agent in patients with hypercholesterolemia. Previous studies revealed that FV also exhibits antioxidant, anti-inflammatory, and antitumor activity. Additionally, our previous study indicated that FV exerts a prophylactic effect on DOXO-induced testicular toxicity by preventing lipid peroxidation, supporting the antioxidant system, and regulating the blood-testis barrier-associated genes expression. Herein, we purposed to evaluate the possible therapeutic and the protective effects of FV on the DOXO-induced cardiac and renal toxicitiy model by histochemical, immunohistochemical, biochemical, and real-time polymerase chain reaction (real-time PCR) analyses. Results point out protective use of FV exerts a beneficial effect by repressing lipid peroxidation and by regulating the inducible nitric oxide synthase (iNOS), nitric oxide synthase endothelial (eNOS), nuclear factor kappa-B (NF-κB), and Caspase-3 (Casp3) protein and mRNA expressions, which play an important role in mediating DOXO-induced renal and cardiac toxicity mechanisms. In conclusion, FV may be a candidate agent for the prevention of renal and cardiac toxicities in cancer patients receiving DOXO chemotherapy.

Anthracycline-induced cardiotoxicity in women without cardiovascular diseases: molecular and genetic predictors

OBJECTIVE

To evaluate role of molecular (endothelin-1, soluble Fas-L, NT-proBNP, TNF-α, interleukin-1β,) and genetic factors (NOS3 (rs1799983), EDNRA (C + 70G, rs5335), NADPH oxidase (C242T, rs4673), p53 protein (polymorphic marker-Arg72Pro exon 4, rs1042522), NOS3 (Glu298Asp, rs1799983), Caspase 8 (CASP8, rs3834129 and rs1045485), interleukin-1β gene (Il-1β, rs1143634), TNF-α gene (rs1800629), SOD2 (rs4880), GPX1 (rs1050450) in development of anthracycline-induced cardiotoxicity (AIC) in women without cardiovascular diseases.

METHODS

A total of 176 women with breast cancer and without cardiovascular diseases who received anthracyclines were enrolled in the study. After the 12 months of chemotherapy (CT), all patients were divided into two groups: group 1 (n = 52) comprised patients with AIC, group 2 (n = 124) comprised those without it.

RESULTS

Based on ROC-analysis, levels of endothelin-1 of ≥9.0 pg/mL (AUC of 0.699), sFas-L of ≥98.3 ng/mL (AUC of 0.990), and NT-proBNP of ≥71.5 pg/mL (AUC of 0.994;) were identified as a cut-off values predicting AIC during 12 months after CT. Whereas, NT-proBNP and sFas-L were more significant predictors than endothelin-1 (p < 0.001). The development of AIC was significantly related to Arg/Arg of p53 protein gene (OR = 2.972; p = 0.001), T/T of NOS3 gene (OR = 3.059, p = 0.018), T/T of NADPH oxidase gene (OR = 2.753, p = 0.008), and C/C of GPX1 (OR = 2.345; p = 0.007).

CONCLUSION

Evaluation of polymorphisms genes of p53 (rs1042522), NOS3 (rs1799983), GPX1 (rs1050450), and NADPH oxidase (rs4673) can be recommended before CT for the risk assessment of AIC development. The serum levels of NT-proBNP and soluble Fas-L after CT may be considered as non-invasive biomarkers for prediction of AIC development during the 12 months.

Inflammatory markers S100A8/A9 and metabolic alteration for evaluating signs of early phase toxicity of anticancer agent treatment

Anticancer agents can cause various side effects, including tissue damages/inflammatory reactions. Drug-responsive biomarkers are essential for evaluating drug toxicity in disease processes. S100 calcium-binding proteins A8/A9 (S100A8/A9) are highly expressed in neutrophils and monocytes/macrophages accumulated at inflammatory sites and are known to be related to tissue damage/inflammation; however, their response to drug toxicity has not been reported. Herein, we investigated the effects of anticancer agents (doxorubicin, cisplatin, and docetaxel) on S100A8/A9 gene expression profiles in four representative tissues (heart, kidney, liver, and lung) in normal C57BL/6J mice. Both S100A8/A9 expression was transiently or time-dependently elevated in four tissues within 48 h after dosing of the three anticancer agents under toxicity-inducing conditions. S100A8/A9 patterns differed among agents and tissues. This result suggests that S100A8/A9 is useful for evaluating anticancer agent-induced tissue damage. Metabolomic analysis revealed that some metabolites showed temporal patterns similar to that of S100A8/A9 expression. The amounts of fumarate (doxorubicin-treated heart), tyrosine (cisplatin-treated kidney), acetylcarnosine (doxorubicin-treated liver), and 2-phosphoglycerate (docetaxel-treated lung) showed similar patterns to that of S100A8/A9 expression. Although these metabolites showed different behaviors between tissues and serum, they may be useful marker candidates for evaluating anticancer agent-induced tissue damage at an earlier stage after dosing.

Mitochondria and Doxorubicin-Induced Cardiomyopathy: A Complex Interplay

Cardiotoxicity has emerged as a major side effect of doxorubicin (DOX) treatment, affecting nearly 30% of patients within 5 years after chemotherapy. Heart failure is the first non-cancer cause of death in DOX-treated patients. Although many different molecular mechanisms explaining the cardiac derangements induced by DOX were identified in past decades, the translation to clinical practice has remained elusive to date. This review examines the current understanding of DOX-induced cardiomyopathy (DCM) with a focus on mitochondria, which were increasingly proven to be crucial determinants of DOX-induced cytotoxicity. We discuss DCM pathophysiology and epidemiology and DOX-induced detrimental effects on mitochondrial function, dynamics, biogenesis, and autophagy. Lastly, we review the current perspectives to contrast the development of DCM, which is still a relatively diffused, invalidating, and life-threatening condition for cancer survivors.

Genetics of Anthracycline-Associated Cardiotoxicity

Anthracyclines are a major component of chemotherapies used in many pediatric and adult malignancies. Anthracycline-associated cardiotoxicity (ACT) is a dose-dependent adverse effect that has substantial impact on morbidity and mortality. Therefore, the identification of genetic variants associated with increased risk of ACT has the potential for significant clinical impact to improve patient care. The goal of this review is to summarize the current evidence supporting genetic variants associated with ACT, identify gaps and limitations in current knowledge, and propose future directions for incorporating genetics into clinical practice for patients treated with anthracyclines. We will discuss mechanisms of ACT that could be illuminated by genetics and discuss clinical applications for the cardiologist/cardio-oncologist.

Network-driven targeted analysis reveals that Astragali Radix alleviates doxorubicin-induced cardiotoxicity by maintaining fatty acid homeostasis

ETHNOPHARMACOLOGICAL RELEVANCE

Astragali Radix (AR) is a popular traditional Chinese medicine that has been used for more than 2000 years. It is a well-known tonic for weak people with chronic diseases, such as heart failure and cerebral ischemia. Previous studies have reported that AR could support the "weak heart" of cancer patients who suffered from doxorubicin (DOX)-induced cardiotoxicity (DIC). However, the underlying mechanism remains unclear.

AIM OF THE STUDY

This study aimed to uncover the critical pathways and molecular determinants for AR against DIC by fully characterizing the network-based relationship.

MATERIALS AND METHODS

We integrated ultra-high-performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS) profiling, database and literature searching, and the human protein-protein interactome to discover the specific network module associated with AR against DIC. To validate the network-based findings, a low-dose, long-term DIC mouse model and rat cardiomyoblast H9c2 cells were employed. The levels of potential key metabolites and proteins in hearts and cells were quantified by the LC-MS/MS targeted analysis and western blotting, respectively.

RESULTS

We constructed one of the most comprehensive AR component-target network described to date, which included 730 interactions connecting 64 unique components and 359 unique targets. Relying on the network-based evaluation, we identified fatty acid metabolism as a putative critical pathway and peroxisome proliferator-activated receptors (PPARα and PPARγ) as potential molecular determinants. We then confirmed that DOX caused the accumulation of fatty acids in the mouse failing heart, while AR promoted fatty acid metabolism and preserved heart function. By inhibiting PPARγ in H9c2 cells, we further found that AR could alleviate DIC by activating PPARγ to maintain fatty acid homeostasis.

CONCLUSIONS

Our findings imply that AR is a promising drug candidate that treats DIC by maintaining fatty acid homeostasis. More importantly, the network-based method developed here could facilitate the mechanism discovery of AR therapy and help catalyze innovation in its clinical application.

Underlying the Mechanisms of Doxorubicin-Induced Acute Cardiotoxicity: Oxidative Stress and Cell Death

Cancer is a destructive disease that causes high levels of morbidity and mortality. Doxorubicin (DOX) is a highly efficient antineoplastic chemotherapeutic drug, but its use places survivors at risk for cardiotoxicity. Many studies have demonstrated that multiple factors are involved in DOX-induced acute cardiotoxicity. Among them, oxidative stress and cell death predominate. In this review, we provide a comprehensive overview of the mechanisms underlying the source and effect of free radicals and dependent cell death pathways induced by DOX. Hence, we attempt to explain the cellular mechanisms of oxidative stress and cell death that elicit acute cardiotoxicity and provide new insights for researchers to discover potential therapeutic strategies to prevent or reverse doxorubicin-induced cardiotoxicity.

Endoplasmic Reticulum Stress Promotes iNOS/NO and Influences Inflammation in the Development of Doxorubicin-Induced Cardiomyopathy

Doxorubicin (Dox) is known to cause heart failure in some cancer patients. Despite extensive studies over the past half century, the subcellular basis of Dox-induced cardiomyopathy (DIC) is still elusive. Earlier, we suggested that Dox causes a delayed activation of unfolded protein response (UPR) which may promote mitochondrial Bax activity leading to cardiomyocyte death. As a follow up, using NO donor, S-Nitroso-N-acetyl-d,l-penicillamine (SNAP), and/or NOS inhibitor, N(ω)-nitro-L-arginine methyl ester (L-NAME), we now show that endoplasmic reticulum (ER) stress promotes inflammation through iNOS/NO-induced TLR2 activation. In vivo Dox treatment increased mitochondrial iNOS to promote ER stress as there was an increase in Bip (Grp78) response, proapoptotic CHOP (DDIT3) and ER-mediated Caspase 12 activation. Increased iNOS activity is associated with an increase in TLR2 and TNF-α receptor associated factor 2 (TRAF2). These two together with NF-κB p105/50 expression and a synergistic support through ER stress, promote inflammatory response in the myocardium leading to cell death and ultimately fostering DIC conditions. In the presence of NOS inhibitor, such detrimental effects of Dox were inhibited, suggesting iNOS/NO as key mediators of Dox-induced inflammatory as well as apoptotic responses.

Protective Potential of Ginseng and/or Coenzyme Q10 on Doxorubicin-induced Testicular and Hepatic Toxicity in Rats

Introduction: Although doxorubicin (DOX) is a successful cancer chemotherapeutic, side effects limit the clinical utility of DOX-based therapy, including male infertility and hepatotoxicity. Objective: To evaluate the testicular and hepatoprotective effect of ginseng and/or coenzyme Q10 (CoQ10) in rats exposed to DOX and the possible underlying mechanisms. Materials and Methods:  Fifty adult male albino rats were divided into (10/group), control, DOX group, DOX/Gin group, DOX/CoQ10 group and DOX/Gin+CoQ10 group. Serum testosterone, serum liver enzymes, fasting serum cholesterol and triglyceride (TG), tissue malondialdehyde (MDA), tissue superoxide dismutase (SOD), serum tumor necrosis factor-alpha (TNF-α), serum interleukin 6, serum interleukin 10, nuclear factor E2‐related factor 2 (Nrf2) gene expression in liver and testis and organ indices were measured.  Histopathological and immunohistochemical assessments of apoptotic marker kaspase3 in testis and liver were also performed. Results DOX-induced toxicity is associated with a significant decrease in serum testosterone, testis and liver index values, testicular and hepatic SOD,  testicular and hepatic Nrf2 gene expression and serum interleukin 10. However, there was a significant increase in serum liver enzymes, serum cholesterol and TG, testicular and hepatic MDA, serum TNF-α and serum interleukin 6 when compared with the control group. The combination of ginseng and CoQ10 resulted in significant improvement of DOX-induced changes when compared with other treated groups. Conclusion: Ginseng and CoQ10 have valuable therapeutic effects on DOX-induced testicular and hepatic toxicity via up-regulation of Nrf2 gene expression, inhibition of apoptosis, anti-oxidant, anti-inflammatory and hypolipidemic effects.

Protective Role of Vitamin B1 in Doxorubicin-Induced Cardiotoxicity in Rats: Focus on Hemodynamic, Redox, and Apoptotic Markers in Heart

Up until now, the specific mechanisms involved in doxorubicin (DOX)-induced cardiotoxicity have not been fully elucidated. Since thiamine deficiency is associated with myocardial dysfunction and it may lead to cardiomyopathy, we aimed to investigate whether thiamine (Vitamin B₁) treatment provides cardioprotection and modulates DOX mediated subchronic cardiotoxicity as well as to determine possible mechanisms of its effects. The study involved 48 Wistar albino rats divided into four groups: healthy non-treated rats and healthy rats treated with thiamine and DOX rats without treatment and DOX rats treated with thiamine. DOX was applied as a single i.p.injection (15mg/kg), while thiamine treatment lasted 7days (25mg/kg/dayi.p.). Before and after the treatment hemodynamic changes were monitored in vivo by echocardiography. When the protocol was completed, animals were sacrificed and rat hearts were isolated in order to evaluate parameters of cardiac oxidative stress [superoxide anion radical-O₂ ^-, hydrogen peroxide-H₂O₂, nitric oxide-NO^-, index of lipid peroxidation-thiobarbituric acid (TBA) reactive substances (TBARS), superoxide dismutase - SOD, catalase (CAT), and reduced glutathione-GSH] and apoptosis (Bax, Bcl-2, caspases). DOX treatment significantly reduced the ejection fraction, while thiamine treatment led to its minor increase in the DOX-treated group. In that sense, heart oxidative stress markers were significantly increased in DOX-treated rats, while therapeutic dose of thiamine decreased the levels of free radicals. Our study demonstrated the promising ameliorative effects of thiamine against DOX-induced cardiotoxicity through modulation of oxidative stress, suppression of apoptosis, and possibility to improve myocardial performance and morphometric structure of rats` hearts.

Acute and Delayed Doxorubicin-Induced Myocardiotoxicity Associated with Elevation of Cardiac Biomarkers, Depletion of Cellular Antioxidant Enzymes, and Several Histopathological and Ultrastructural Changes

Doxorubicin (DOX; Adricin) is an anthracycline antibiotic, which is an efficient anticancer chemotherapeutic agent that targets many types of adult and pediatric tumors, such as breast cancer, leukemia, and lymphomas. However, use of DOX is limited due to its cardiotoxic effects. This study sequentially investigated the mechanistic pathways of the cardiotoxic process of DOX in rats at different post-treatment periods using cumulative dose, which is used in therapeutic regimes. In this regard, 56 male albino rats were used for the experiment. The experimental animals were divided into seven groups (n = 8/group) based on dose and sacrifice schedule as follows: G1 (2 mg/kg body weight [BW] and sacrificed at day 4), G2 (4 mg/kg BW and sacrificed at day 8), G3 (6 mg/kg BW and sacrificed at day 15), G4 (8 mg/kg BW and sacrificed at day 30), G5 (10 mg/kg BW and sacrificed at day 60), G6 (10 mg/kg BW and sacrificed at day 90), and G7 (10 mg/kg BW and sacrificed at day 120). As expected, G1, G2, and G3-treated groups revealed features of acute toxic myocarditis associated with degenerative and necrotic changes in myocytes, mitochondrial damage, elevation of cardiac biomarkers, and depletion of cellular antioxidant enzymes. However, these changes increased in severity with subsequent treatment with the same dose until reaching a cumulative dose of 10 mg/kg BW for 30 d. Furthermore, after a cumulative dose of 10 mg/kg BW with a withdrawal period of 2–3 months, various predominant changes in chronicity were reported, such as disorganization and atrophy of myocytes, condensation and atrophy of mitochondria, degranulation of mast cells, and fibrosis with occasional focal necrosis, indicating incomplete elimination of DOX and/or its metabolites. Altogether, these data provide interesting observations associated with the cardiotoxic process of DOX in rats that would help understand the accompanying changes underlying the major toxic effects of the drug. Future research is suggested to explore more about the dose-dependent mechanisms of such induced toxicity of DOX that would help determine the proper doses and understand the resulting cardiomyopathy.

Protective Effects of Oroxylin A against Doxorubicin-Induced Cardiotoxicity via the Activation of Sirt1 in Mice

Doxorubicin- (DOX-) related cardiac injury impairs the life quality of patients with cancer. This largely limited the clinical use of DOX. It is of great significance to find a novel strategy to reduce DOX-related cardiac injury. Oroxylin A (OA) has been identified to exert beneficial effects against inflammatory diseases and cancers. Here, we investigated whether OA could attenuate DOX-induced acute cardiotoxicity in mice. A single dose of DOX was used to induce acute cardiac injury in mice. To explore the protective effects, OA was administered to mice for ten days beginning from five days before DOX injection. The data in our study indicated that OA inhibited DOX-induced heart weight loss, reduction in cardiac function, and the elevation in myocardial injury markers. DOX injection resulted in increased oxidative damage, inflammation accumulation, and myocardial apoptosis in vivo and in vitro, and these pathological alterations were alleviated by treatment of OA. OA activated the sirtuin 1 (Sirt1) signaling pathway via the cAMP/protein kinase A, and its protective effects were blocked by Sirt1 deficiency. OA treatment did not affect the tumor-killing action of DOX in tumor-bearing mice. In conclusion, OA protected against DOX-related acute cardiac injury via the regulation of Sirt1.

Effect of Nardostachys jatamansi DC. on Apoptosis, Inflammation and Oxidative Stress Induced by Doxorubicin in Wistar Rats

The study aimed to investigate the protective action of jatamansi (Nardostachys jatamansi DC.) against doxorubicin cardiotoxicity. Methanolic extract of jatamansi (MEJ) was prepared and standardized using HPTLC fingerprinting, GC-MS chemoprofiling, total phenolic content, and antioxidant activity in vitro. Further in vivo activity was evaluated using rodent model. Animals were divided into five groups (n = 6) namely control (CNT) (Normal saline), toxicant (TOX, without any treatment), MEJ at low dose (JAT1), MEJ at high dose (JAT2), and standard desferrioxamine (STD). All groups except control received doxorubicin 2.5 mg per Kg intra-peritoneally for 3 weeks in twice a week regimen. After 3 weeks, the blood samples and cardiac tissues were collected from all groups for biochemical and histopathological evaluation. Treatment with MEJ at both dose levels exhibited significant reduction (p < 0.001 vs. toxicant) of serum CK-MB (heart creatine kinase), LDH (Lactate dehydrogenase) & HMG-CoA (3-hydroxy-3-methylglutaryl-coenzyme A) levels, and tissue MDA (melondialdehyde) level; insignificant difference was observed (p > 0.05) in TNF-alpha (tumour necrosis factor), IL-6 (interleukine-6) levels and caspase activity as compared to TOX. Histopathological evaluation of cardiac tissues of different treatment groups further reinforced the findings of biochemical estimation. This study concludes that jatamansi can protect cardiac tissues from oxidative stress-induced cell injury and lipid peroxidation as well as against inflammatory and apoptotic effects on cardiac tissues.

Possible Susceptibility Genes for Intervention against Chemotherapy-Induced Cardiotoxicity

Recent therapeutic advances have significantly improved the short- and long-term survival rates in patients with heart disease and cancer. Survival in cancer patients may, however, be accompanied by disadvantages, namely, increased rates of cardiovascular events. Chemotherapy-related cardiac dysfunction is an important side effect of anticancer therapy. While advances in cancer treatment have increased patient survival, treatments are associated with cardiovascular complications, including heart failure (HF), arrhythmias, cardiac ischemia, valve disease, pericarditis, and fibrosis of the pericardium and myocardium. The molecular mechanisms of cardiotoxicity caused by cancer treatment have not yet been elucidated, and they may be both varied and complex. By identifying the functional genetic variations responsible for this toxicity, we may be able to improve our understanding of the potential mechanisms and pathways of treatment, paving the way for the development of new therapies to target these toxicities. Data from studies on genetic defects and pharmacological interventions have suggested that many molecules, primarily those regulating oxidative stress, inflammation, autophagy, apoptosis, and metabolism, contribute to the pathogenesis of cardiotoxicity induced by cancer treatment. Here, we review the progress of genetic research in illuminating the molecular mechanisms of cancer treatment-mediated cardiotoxicity and provide insights for the research and development of new therapies to treat or even prevent cardiotoxicity in patients undergoing cancer treatment. The current evidence is not clear about the role of pharmacogenomic screening of susceptible genes. Further studies need to done in chemotherapy-induced cardiotoxicity.

The Role of Oxidative Stress in Physiopathology and Pharmacological Treatment with Pro- and Antioxidant Properties in Chronic Diseases

Oxidative stress (OS) has the ability to damage different molecules and cellular structures, altering the correct function of organs and systems. OS accumulates in the body by endogenous and exogenous mechanisms. Increasing evidence points to the involvement of OS in the physiopathology of various chronic diseases that require prolonged periods of pharmacological treatment. Long-term treatments may contribute to changes in systemic OS. In this review, we discuss the involvement of OS in the pathological mechanisms of some chronic diseases, the pro- or antioxidant effects of their pharmacological treatments, and possible adjuvant antioxidant alternatives. Diseases such as high blood pressure, arteriosclerosis, and diabetes mellitus contribute to the increased risk of cardiovascular disease. Antihypertensive, lipid-lowering, and hypoglycemic treatments help reduce the risk with an additional antioxidant benefit. Treatment with methotrexate in autoimmune systemic inflammatory diseases, such as rheumatoid arthritis, has a dual role in stimulating the production of OS and producing mitochondrial dysfunction. However, it can also help indirectly decrease the systemic OS induced by inflammation. Medicaments used to treat neurodegenerative diseases tend to decrease the mechanisms related to the production of reactive oxygen species (ROS) and balance OS. On the other hand, immunosuppressive treatments used in cancer or human immunodeficiency virus infection increase the production of ROS, causing significant oxidative damage in different organs and systems without widely documented exogenous antioxidant administration alternatives.

Pyrophen Isolated from the Endophytic Fungus Aspergillus fumigatus Strain KARSV04 Synergizes the Effect of Doxorubicin in Killing MCF7 but not T47D Cells

Objectives

Pyrophen, an amino acid-pyrone derivative isolated from Aspergillus fumigatus strain KARSV04 has been reported to have an anticancer effect on T47D cells by inhibiting the growth of cells and modulating the cell cycle in the S phase. In the present study, the effect of pyrophen in doxorubicin (Dox) chemotherapy in an in vitro model of breast cancers was studied.

Materials and Methods

The cytotoxicity of pyrophen and Dox separately and in combination were evaluated in T47D and MCF-7 cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Modulation of cell cycle distribution and apoptosis was examined by flow cytometry.

Results

Our findings showed that pyrophen did not significantly potentiate Dox-induced cytotoxicity in T47D cells. Adding Dox-treated T47D cells with pyrophen at a concentration of 9.20 μg/mL induced a slight increase in the S-phase cell population. This compound induced cytotoxicity of MCF-7 cells with IC₅₀ of 70.57 μg/mL. Co-treatment of pyrophen and Dox in MCF-7 cells increased cytotoxicity relative to Dox alone, which was suggested in part to be due to modulation of the cell cycle in the G2/M phase and apoptosis.

Conclusion

The data suggest different mechanisms of regulation in promoting cell death by two different cell lines in response to administration of pyrophen.

Osteocrin attenuates inflammation, oxidative stress, apoptosis, and cardiac dysfunction in doxorubicin-induced cardiotoxicity

Background

Inflammation, oxidative stress, and apoptosis contribute to the evolution of doxorubicin (DOX)‐induced cardiotoxicity. Osteocrin (OSTN) is a novel secretory peptide mainly derived from the bone and skeletal muscle, and plays critical roles in regulating bone growth and physical endurance. Inspiringly, OSTN was also reported to be abundant in the myocardium that functioned as a therapeutic agent against cardiac rupture and congestive heart failure in mice after myocardial infarction. Herein, we investigated the role and potential mechanism of OSTN in DOX‐induced cardiotoxicity.

Methods

Cardiac‐restrict OSTN overexpression was performed by the intravenous injection of a cardiotropic AAV9 vector, and subsequently the mice received 15 mg/kg DOX injection (i.p., once) to induce acute cardiac injury. Besides, H9C2 cell lines were used to assess the possible role of OSTN in vitro by incubating with recombinant human OSTN or small interfering RNA against Ostn (siOstn). To clarify the involvement of protein kinase G (PKG), KT5823 and siPkg were used in vivo and in vitro. Mice were also administrated intraperitoneally with 5 mg/kg DOX weekly for consecutive 3 weeks at a cumulative dose of 15 mg/kg to mimic the cardiotoxic effects upon chronic DOX exposure.

Results

OSTN treatment notably attenuated, whereas OSTN silence exacerbated inflammation, oxidative stress, and cardiomyocyte apoptosis in DOX‐treated H9C2 cells. Besides, cardiac‐restrict OSTN‐overexpressed mice showed an alleviated cardiac injury and malfunction upon DOX injection. Mechanistically, we found that OSTN activated PKG, while PKG inhibition abrogated the beneficial effect of OSTN in vivo and in vitro. As expected, OSTN overexpression also improved cardiac function and survival rate in mice after chronic DOX treatment.

Conclusions

OSTN protects against DOX‐elicited inflammation, oxidative stress, apoptosis, and cardiac dysfunction via activating PKG, and cardiac gene therapy with OSTN provides a novel therapeutic strategy against DOX‐induced cardiotoxicity.

Transcriptomic Analysis of Human Mesenchymal Stem Cell Therapy in Incontinent Rat Injured Urethra

Periurethral human mesenchymal stem cell (hMSC) injections are associated with functional improvement in animal models of postpartum stress urinary incontinence (SUI). However, limited data exist on the role of hMSCs in modulating gene expression in tissue repair after urethral injury. To this end, we quantified temporal gene expression modulation in hMSCs, and in injured rat urethral tissue, using RNA-seq in an animal model of SUI, over a 3-day period following urethral injury, and local hMSC injection. We injected PKH fluorescent-labeled hMSC into the periurethral space of rats following a 4 h vaginal distention (VD) (three rats per time point). Control rats underwent VD injury only, and all animals were euthanized at 12, 24, 36, 72 h postinjury. Rat urethral and vaginal tissues were frozen and sectioned. Fluorescent labeled hMSCs were distinguished from adjacent, unlabeled rat urethral tissue. RNA was prepared from hMSCs and urethral tissue obtained by laser dissection of frozen tissue sections and sequenced on an Illumina HiSeq 2500. Differentially expressed genes (DEGs) over 72 h were evaluated using a two-group t-test (p < 0.05). Our transcriptional analyses identified candidate genes involved in tissue injury that were broadly sorted by injury and exposure to hMSC throughout the first 72 h of acute phase of injury. DEGs in treated urethra, compared with untreated urethra, were functionally associated with tissue repair, angiogenesis, neurogenesis, and oxidative stress suppression. DEGs included a variety of cytokines, extracellular matrix stabilization and regeneration genes, cytokine signaling modification, cell cycle regulation, muscle differentiation, and stabilization. Moreover, our results revealed DEG changes in hMSCs (PKH-labeled) harvested from injured urethra. The expressions are related to DNA damage repair, transcription activation, stem cell regulation, cell survival, apoptosis, self-renewal, cell proliferation, migration, and injury response. Impact statement Stress urinary incontinence (SUI) affects nearly half of women over 40, resulting in reduced quality of life and increased health care cost. Development of SUI is multifactorial and strongly associated with vaginal delivery. While stem cell therapy in animal models of SUI and limited preliminary clinical trials demonstrate functional improvement of SUI, the role of stem cell therapy in modulating tissue repair is unclear impeding advanced clinical trials. Our work provides a new understanding of the transcriptional mechanisms with which human mesenchymal stem cells improve acute injury repair thus guiding the development of cell-based therapies for women with nonacute established SUI.

Cardiac Damage in Anthracyclines Therapy: Focus on Oxidative Stress and Inflammation

Significance: Despite their serious side effects, anthracyclines (ANTs) are the most prescribed chemotherapeutic drugs because of their strong efficacy in both solid and hematological tumors. A major limitation to ANTs clinical application is the severe cardiotoxicity observed both acutely and chronically. The mechanism underlying cardiac dysfunction under chemotherapy is mainly dependent on the generation of oxidative stress and systemic inflammation, both of which lead to progressive cardiomyopathy and heart failure. Recent Advances: Over the years, the iatrogenic ANTs-induced cardiotoxicity was believed to be simply given by iron metabolism and reactive oxygen species production; however, several experimental data indicate that ANTs may use alternative damaging mechanisms, such as topoisomerase 2β inhibition, inflammation, pyroptosis, immunometabolism, and autophagy. Critical Issues: In this review, we aimed at discussing ANTs-induced cardiac injury from different points of view, updating and focusing on oxidative stress and inflammation, since these pathways are not exclusive or independent from each other but they together importantly contribute to the complexity of ANTs-induced multifactorial cardiotoxicity. Future Directions: A deeper understanding of the mechanistic signaling leading to ANTs side effects could reveal crucial targeting molecules, thus representing strategic knowledge to promote better therapeutic efficacy and lower cardiotoxicity during clinical application.

Cardioprotection in cancer therapy: novel insights with anthracyclines

Anthracyclines are a class of antineoplastic agents that remain critical to modern-day cancer treatment. However, their propensity to cause cardiotoxic effects limits their use and can cause increased morbidity and mortality among patients with cancer. Currently available methods to minimize the impact of anthracycline cardiotoxicity have not been widely successful. While it is largely accepted that the generation of oxygen radicals contributes to the development of anthracycline cardiotoxicity, the exact mechanisms of cardiomyocyte injury remain unclear. In this review, we discuss the current state of basic and translational research on the cardiotoxic mechanisms of anthracyclines that have led to the discovery of new therapeutic targets. Pending validation in patient populations, these recent advances have the potential to be translated into clinical approaches that will minimize anthracycline cardiotoxicity and improve outcomes in cancer survivors.

Antitumour Anthracyclines: Progress and Perspectives

Anthracyclines are ranked among the most effective chemotherapeutics against cancer. They are glycoside drugs comprising the amino sugar daunosamine linked to a hydroxy anthraquinone aglycone, and act by DNA intercalation, oxidative stress generation and topoisomerase II poisoning. Regardless of their therapeutic value, multidrug resistance and severe cardiotoxicity are important limitations of anthracycline treatment that have prompted the discovery of novel analogues. This review covers the most clinically relevant anthracyclines and their development over decades, since the first discovered natural prototypes to recent semisynthetic and synthetic derivatives. These include registered drugs, drug candidates undergoing clinical trials, and compounds under pre-clinical investigation. The impact of the structural modifications on antitumour activity, toxicity and resistance profile is addressed.

Protective effect of curcumin nanoparticles against cardiotoxicity induced by doxorubicin in rat

The present study designed to investigate the protective effect of curcumin nanoparticles (CUR-NPs) on the cardiotoxicity induced by doxorubicin. Rats were divided into four groups; control, rats treated daily with CUR-NPs (50 mg/kg) for 14 days, rats treated with an acute dose of doxorubicin (20 mg/kg) and rats treated daily with CUR-NPs for 14 days injected with doxorubicin on the 10th day. After electrocardiogram (ECG) recording from rats at different groups, rat decapitation was carried out and the heart of each rat was excised out to measure the oxidative stress parameters; lipid peroxidation (MDA), nitric oxide (NO) and reduced glutathione (GSH) and the activities of Na,K,ATPase and acetylcholinesterase (AchE). In addition, the levels of dopamine (DA), norepinephrine (NE) and serotonin (5-HT) were determined in the cardiac tissues. Lactate dehydrogenase (LDH) activity was measured in the serum. The ECG recordings indicated that daily pretreatment with CUR- NPs has prevented the tachycardia (i.e. increase in heart rate) and ameliorated the changes in ST wave and QRS complex induced by doxorubicin. In addition, CUR-NPs prevented doxorubicin induced significant increase in MDA, NO, DA, AchE and LDH and doxorubicin induced significant decrease in GSH, NE, 5-HT and Na,K,ATPase. According to the present findings, it could be concluded that CUR-NPs have a protective effect against cardiotoxicity induced by doxorubicin. This may shed more light on the importance of CUR-NPs pretreatment before the application of doxorubicin therapy.

lncRNA HOXB-AS3 protects doxorubicin-induced cardiotoxicity by targeting miRNA-875-3p

Protective role of lncRNA HOXB-AS3 in doxorubicin (DOX)-induced cardiotoxicity and its mechanism were studied. Viability of PC and H9c2 cells treated with different doses of DOX was determined through CCK-8 assay. Relative level of HOXB-AS3 in DOX-treated cardiomyocytes was detected. Regulatory effect of HOXB-AS3 on the proliferative ability of DOX-treated cardiomyocytes was assessed. Through dual-luciferase reporter gene assay, the binding relationship between HOXB-AS3 and miRNA-875-3p was verified. Rescue experiments were conducted to explore the role of HOXB-AS3/miRNA-875-3p in influencing the proliferation of DOX-treated cardiomyocytes. The proliferative ability of cardiomyocytes was dose-dependently downregulated after DOX treatment. Relative level of HOXB-AS3 was upregulated in DOX-treated cardiomyocytes. Silence of HOXB-AS3 in cardiomyocytes undergoing DOX treatment markedly elevated their proliferative ability. miRNA-875-3p was the direct target of HOXB-AS3. Knockdown of miRNA-875-3p reversed the role of HOXB-AS3 in regulating the proliferative ability of cardiomyocytes. HOXB-AS3 protects DOX-induced suppression in the proliferation of cardiomyocytes through targeting and downregulating miRNA-875-3p.

Effects of doxorubicin on the heart: From molecular mechanisms to intervention strategies

Cancer remains a major public health problem worldwide and was responsible for 9.6 million deaths in 2018. Oncologic treatments such as doxorubicin (Dox) and trastuzumab (Trz) are chemotherapeutic drugs used to treat several types of cancer, including solid and non-solid malignancies. Although these drugs have a significant impact on the reduction in mortality of cancer patients, this treatment has an adverse effect on the cardiovascular system. The mechanisms associated with Dox-induced cardiotoxicity involve inflammation, oxidative stress, apoptosis, mitochondria impairment and dysregulation of autophagy. Unfortunately, Trz, an effective anti-cancer drug, can potentiate these adverse effects. Trz is a recombinant DNA-derived humanized monoclonal antibody against human epidermal growth factor receptor 2 (HER2). Despite its high anti-cancer efficacy, Trz also has a cardiotoxic effect. Unlike Dox, this adverse effect of Trz on the heart is mostly reversible. A strategy to prevent this undesirable effect is urgently needed. Currently, several pharmacological interventions have shown promising results that might effectively attenuate Dox- and Trz-induced cardiac dysfunction. In this review, reports from in vitro, in vivo and clinical studies pertinent to the underlying mechanisms involved in chemotherapy-induced cardiotoxicity, are comprehensively summarized and discussed. In addition, the potential pharmacological interventions to prevent these cardiotoxic effects are described.

Major obstacles to doxorubicin therapy: Cardiotoxicity and drug resistance

Background

Doxorubicin is one of the most commonly prescribed and time-tested anticancer drugs. Although being considered as a first line drug in different types of cancers, the two main obstacles to doxorubicin therapy are drug-induced cardiotoxicity and drug resistance.

Method

The study utilizes systemic reviews on publications of previous studies obtained from scholarly journal databases including PubMed, Medline, Ebsco Host, Google Scholar, and Cochrane. The study utilizes secondary information obtained from health organizations using filters and keywords to sustain information relevancy. The study utilizes information retrieved from studies captured in the peer-reviewed journals on “doxorubicin-induced cardiotoxicity” and “doxorubicin resistance.”

Discussion and results

The exact mechanisms of cardiotoxicity are not known; various hypotheses are studied. Doxorubicin can lead to free radical generation in various ways. The commonly proposed underlying mechanisms promoting doxorubicin resistance are the expression of multidrug resistance proteins as well as other causes.

Conclusion

In this review, we have described the major obstacles to doxorubicin therapy, doxorubicin-induced cardiotoxicity as well as the mechanisms of cancer drug resistance and in following the treatment failures.

Aspirin ameliorates the long-term adverse effects of doxorubicin through suppression of cellular senescence

A number of childhood cancer survivors develop adverse, late onset side effects of earlier cancer treatments, known as the late effects of cancer therapy. As the number of survivors continues to increase, this growing population is at increased risk for a number of health-related problems. In the present study, we have examined the effect of aspirin on the late effects of chemotherapy by treating juvenile mice with doxorubicin (DOX). This novel mouse model produced various long-term adverse effects, some of which resemble premature aging phenotypes. DOX also resulted in the tissue accumulation of senescent cells and up-regulation of cyclooxygenase-2 (COX2) expression. However, treatment with aspirin following juvenile exposure to DOX improved body weight gain, ameliorated the long-term adverse effects, and reduced the levels of senescence markers. Moreover, aspirin reduced p53 and p21 accumulation in DOX-treated human and mouse fibroblasts. However, the suppressive effect of aspirin on DOX-induced p53 accumulation was significantly decreased in COX2 knockout mouse embryonic fibroblasts. Additionally, treatment of senescent fibroblasts with aspirin or celecoxib, a COX2 specific inhibitor, reduced cell viability and decreased the levels of Bcl-xL protein. Taken together, these studies suggest that aspirin may be able to reduce the late effects of chemotherapy through the suppression of cellular senescence.

Doxorubicin-Induced Cardiomyopathy in Children

Doxorubicin-induced cardiotoxicity in childhood cancer survivors is a growing problem. The population of patients at risk for cardiovascular disease is steadily increasing, as five-year survival rates for all types of childhood cancers continue to improve. Doxorubicin affects the developing heart differently from the adult heart and in a subset of exposed patients, childhood exposure leads to late, irreversible cardiomyopathy. Notably, the prevalence of late-onset toxicity is increasing in parallel with improved survival. By the year 2020, it is estimated that there will be 500,000 childhood cancer survivors and over 50,000 of them will suffer from doxorubicin-induced cardiotoxicity. The majority of the research to-date, concentrated on childhood cancer survivors, has focused mostly on clinical outcomes through well-designed epidemiological and retrospective cohort studies. Preclinical studies have elucidated many of the cellular mechanisms that elicit acute toxicity in cardiomyocytes. However, more research is needed in the areas of early- and late-onset cardiotoxicity and more importantly improving the scientific understanding of how other cells present in the cardiac milieu are impacted by doxorubicin exposure. The overall goal of this review is to succinctly summarize the major clinical and preclinical studies focused on doxorubicin-induced cardiotoxicity. As the prevalence of patients affected by doxorubicin exposure continues to increase, it is imperative that the major gaps in existing research are identified and subsequently utilized to develop appropriate research priorities for the coming years. Well-designed preclinical research models will enhance our understanding of the pathophysiology of doxorubicin-induced cardiotoxicity and directly lead to better diagnosis, treatment, and prevention. © 2019 American Physiological Society. Compr Physiol 9:905-931, 2019.

Leveraging the Cardio-Protective and Anticancer Properties of Resveratrol in Cardio-Oncology

Cardio-oncology is a clinical/scientific discipline which aims to prevent and/or treat cardiovascular diseases in cancer patients. Although a large number of cancer treatments are known to cause cardiovascular toxicity, they are still widely used because they are highly effective. Unfortunately, therapeutic interventions to prevent and/or treat cancer treatment-induced cardiovascular toxicity have not been established yet. A major challenge for such interventions is to protect the cardiovascular system without compromising the therapeutic benefit of anticancer medications. Intriguingly, the polyphenolic natural compound resveratrol and its analogs have been shown in preclinical studies to protect against cancer treatment-induced cardiovascular toxicity. They have also been shown to possess significant anticancer properties on their own, and to enhance the anticancer effect of other cancer treatments. Thus, they hold significant promise to protect the cardiovascular system and fight the cancer at the same time. In this review, we will discuss the current knowledge regarding the cardio-protective and the anticancer properties of resveratrol and its analogs. Thereafter, we will discuss the challenges that face the clinical application of these agents. To conclude, we will highlight important gaps of knowledge and future research directions to accelerate the translation of these exciting preclinical findings to cancer patient care.

Pediatric Anthracycline-Induced Cardiotoxicity: Mechanisms, Pharmacogenomics, and Pluripotent Stem-Cell Modeling

Anthracycline‐induced cardiotoxicity (ACT) is a severe adverse drug reaction for a subset of children treated with anthracyclines as part of chemotherapy protocols. The identification of genetic markers associated with increased ACT susceptibility has clinical significance toward improving patient care and our understanding of the molecular mechanisms involved in ACT. Human‐induced pluripotent stem cell–derived cardiomyocytes represent a novel approach to determine the pharmacogenomics of ACT and guide the development of genetic screening tests.

AMPK/PGC1α activation by melatonin attenuates acute doxorubicin cardiotoxicity via alleviating mitochondrial oxidative damage and apoptosis

Doxorubicin (DOX) is a highly effective anticancer anthracycline drug, but its side effects at the level of the heart has limited its widespread clinical application. Melatonin is a documented potent antioxidant, nontoxic and cardioprotective agent, and it is involved in maintaining mitochondrial homeostasis and function. The present study established acute DOX-induced cardiotoxicity models in both H9c2 cells incubated with 1 μM DOX and C57BL/6 mice treated with DOX (20 mg/kg cumulative dose). Melatonin markedly alleviated the DOX-induced acute cardiac dysfunction and myocardial injury. Both in vivo and in vitro studies verified that melatonin inhibited DOX-induced mitochondrial dysfunction and morphological disorders, apoptosis, and oxidative stress via the activation of AMPK and upregulation of PGC1α with its downstream signaling (NRF1, TFAM and UCP2). These effects were reversed by the use of AMPK siRNA or PGC1α siRNA in H9c2 cells, and were also negated by the cotreatment with AMPK inhibitor Compound C in vivo. Moreover, PGC1α knockdown was without effect on the AMPK phosphorylation induced by melatonin in the DOX treated H9c2 cells. Therefore, AMPK/PGC1α pathway activation may represent a new mechanism for melatonin exerted protection against acute DOX cardiotoxicity through preservation of mitochondrial homeostasis and alleviation of oxidative stress and apoptosis.

Protective effect of nebivolol on doxorubicin-induced cardiotoxicity in rats

INTRODUCTION

The cardiotoxicity of doxorubicin is incompletely understood. We investigated the prophylactic effect of nebivolol on doxorubicin-induced cardiac toxicity.

MATERIAL AND METHODS

Thirty rats were divided into a control group, doxorubicin-treated group and nebivolol + doxorubicin-treated group. The specimens were examined using H + E and Masson's trichrome, caspase 3, endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS) and tumor necrosis factor factor-α (TNF-α). The mean area percentage of collagen fiber content, caspase-3, eNOS, iNOS and TNF-α immunoactivities was measured.

RESULTS

The doxorubicin-treated group showed marked myocyte distortion and fragmentation, congestion and cytoplasmic lysis in most fibers. These changes were less intense in the nebivolol-treated group. The mean area percentage of collagen fiber in the nebivolol-treated group was non-significantly smaller (p = 0.07) than that in the doxorubicin-treated group. The expression of caspase-3 (p = 0.03), eNOS (p ≤ 0.001), iNOS (p < 0.001) and TNF-α (p = 0.003) immunoreactivity was improved in the nebivolol-treated group.

CONCLUSIONS

Nebivolol exerted a significant protective effect from doxorubicin toxicity. The protective effect appears to be mediated mainly through caspase-3, eNOS, iNOS and TNF-α modulation.

Autophagy and mitophagy in the context of doxorubicin-induced cardiotoxicity

Doxorubicin (Dox) is a cytotoxic drug widely incorporated in various chemotherapy protocols. Severe side effects such as cardiotoxicity, however, limit Dox application. Mechanisms by which Dox promotes cardiac damage and cardiomyocyte cell death have been investigated extensively, but a definitive picture has yet to emerge. Autophagy, regarded generally as a protective mechanism that maintains cell viability by recycling unwanted and damaged cellular constituents, is nevertheless subject to dysregulation having detrimental effects for the cell. Autophagic cell death has been described, and has been proposed to contribute to Dox-cardiotoxicity. Additionally, mitophagy, autophagic removal of damaged mitochondria, is affected by Dox in a manner contributing to toxicity. Here we will review Dox-induced cardiotoxicity and cell death in the broad context of the autophagy and mitophagy processes.

Protective Effect of Boswellic Acids against Doxorubicin-Induced Hepatotoxicity: Impact on Nrf2/HO-1 Defense Pathway

The current study aimed to investigate the potential protective role of boswellic acids (BAs) against doxorubicin- (DOX-) induced hepatotoxicity. Also, the possible mechanisms underlying this protection; antioxidant, as well as the modulatory effect on the Nrf2 transcription factor/hem oxygenase-1 (Nrf2/HO-1) pathway in liver tissues, was investigated. Animals were allocated to five groups: group 1: the saline control, group 2: the DOX group, animals received DOX (6 mg/kg, i.p.) weekly for a period of three weeks, and groups 3–5: animals received DOX (6 mg/kg, i.p.) weekly and received protective doses of BAs (125, 250, and 500 mg/kg/day). Treatment with BAs significantly improved the altered liver enzyme activities and oxidative stress markers. This was coupled with significant improvement in liver histopathological features. BAs increased the Nrf2 and HO-1 expression, which provided protection against DOX-induced oxidative insult. The present results demonstrated that BAs appear to scavenge ROS and inhibit lipid peroxidation and DNA damage of DOX-induced hepatotoxicity. The antioxidant efficacy of BAs might arise from its modulation of the Nrf2/HO-1 pathway and thereby protected liver from DOX-induced oxidative injury.

Inactivation of the Glucose-Dependent Insulinotropic Polypeptide Receptor Improves Outcomes following Experimental Myocardial Infarction

Incretin hormones exert pleiotropic metabolic actions beyond the pancreas. Although the heart expresses both incretin receptors, the cardiac biology of GIP receptor (GIPR) action remains incompletely understood. Here we show that GIPR agonism did not impair the response to cardiac ischemia. In contrast, genetic elimination of the Gipr reduced myocardial infarction (MI)-induced ventricular injury and enhanced survival associated with reduced hormone sensitive lipase (HSL) phosphorylation; it also increased myocardial triacylglycerol (TAG) stores. Conversely, direct GIPR agonism in the isolated heart reduced myocardial TAG stores and increased fatty acid oxidation. The cardioprotective phenotype in Gipr^-/- mice was partially reversed by pharmacological activation or genetic overexpression of HSL. Selective Gipr inactivation in cardiomyocytes phenocopied Gipr^-/- mice, resulting in improved survival and reduced adverse remodeling following experimental MI. Hence, the cardiomyocyte GIPR regulates fatty acid metabolism and the adaptive response to ischemic cardiac injury. These findings have translational relevance for developing GIPR-based therapeutics.