Nrf2 deficiency exaggerates doxorubicin-induced cardiotoxicity and cardiac dysfunction

Marein Alleviates Doxorubicin-Induced Cardiotoxicity through FAK/AKT Pathway Modulation while Potentiating its Anticancer Activity

Doxorubicin (DOX) is an effective anticancer agent, yet its clinical utility is hampered by dose-dependent cardiotoxicity. This study explores the cardioprotective potential of Marein (Mar) against DOX-induced cardiac injury and elucidates underlying molecular mechanisms. Neonatal rat cardiomyocytes (NRCMs) and murine models were employed to assess the impact of Mar on DOX-induced cardiotoxicity (DIC). In vitro, cell viability, oxidative stress were evaluated. In vivo, a chronic injection method was employed to induce a DIC mouse model, followed by eight weeks of Mar treatment. Cardiac function, histopathology, and markers of cardiotoxicity were assessed. In vitro, Mar treatment demonstrated significant cardioprotective effects in vivo, as evidenced by improved cardiac function and reduced indicators of cardiac damage. Mechanistically, Mar reduced inflammation, oxidative stress, and apoptosis in cardiomyocytes, potentially via activation of the Focal Adhesion Kinase (FAK)/AKT pathway. Mar also exhibited an anti-ferroptosis effect. Interestingly, Mar did not compromise DOX's efficacy in cancer cells, suggesting a dual benefit in onco-cardiology. Molecular docking studies suggested a potential interaction between Mar and FAK. This study demonstrates Mar's potential as a mitigator of DOX-induced cardiotoxicity, offering a translational perspective on its clinical application. By activating the FAK/AKT pathway, Mar exerts protective effects against DOX-induced cardiomyocyte damage, highlighting its promise in onco-cardiology. Further research is warranted to validate these findings and advance Mar as a potential adjunctive therapy in cancer treatment.

Tetrastigma hemsleyanum polysaccharide combined with doxorubicin promote ferroptosis and immune function in triple-negative breast cancer

The absence of effective therapeutic targets poses considerable obstacles to the treatment of triple-negative breast cancer (TNBC). This study aimed to explore the function and mechanism of polysaccharides derived from the aerial parts of Tetrastigma hemsleyanum (THP) for the treatment of TNBC. THP exerts notable anti-TNBC effects when used alone, and its combination with Doxorubicin (DOX) effectively augments the sensitivity of TNBC cells to DOX. Through RNA sequencing, Fe2+ assays, western blotting, and transmission electron microscopy, THP was identified as a natural inducer of ferroptosis and ferritinophagy through the xCT/GSH/GPX4 and Nrf2/NCOA4/FTH1 pathways. Further research revealed that the THP branched-chain hexose directly binds to the xCT protein to inhibit its expression and promotes ferroptosis. In vivo experiments confirmed the role of THP in inducing ferroptosis and showed that THP improves the tumor microenvironment and immune function by increasing the ratio of CD4+ and CD8+ T cells to regulatory T cells and modulating cytokine levels. As demonstrated by electrocardiography, blood chemistry, and histological analyses, THP alleviates organ toxicity caused by DOX. Overall, these results suggest that THP has significant clinical potential as a natural macromolecular drug and may provide a safe and effective treatment strategy for TNBC when combined with DOX.

Role of mesenchymal stem cells-derived exosomes on inflammation, apoptosis, fibrosis and telocyte modulation in doxorubicin-induced cardiotoxicity: A closer look at the structural level

Cardiotoxicity induced by doxorubicin (Dox) is a major complication in cancer patients. Exosomes (Ex) derived from mesenchymal cells could be a promising therapeutic for various heart diseases. This study investigated the role of Ex in Dox-induced cardiotoxicity and its mechanistic insights, using Sacubitril/valsartan (S/V) as a reference drug widely recommended in heart failure management. The study involved 24 Wistar rats, divided into a control, Dox, Dox + S/V, and Dox + Ex groups. The rats were assessed for cardiac enzymes, inflammatory and oxidative stress markers. Immunohistochemical expression of caspase-1, nuclear factor erythroid 2-related factor 2 (NrF2), E-Cadherin, CD117/c-kit, and Platelet-derived growth factor-α (PDGFα) was evaluated. P53 and Annexin V were assessed by PCR. Histological examination was performed using hematoxylin and eosin and Sirius red stains. Ex ameliorated the adverse cardiac pathological changes and significantly decreased the cardiac enzymes and inflammatory and oxidative stress markers. Ex also exerted antifibrotic and antiapoptotic effect in heart tissue. Ex treatment also improved NrF2 immunohistochemistry, up-regulated E-Cadherin immune expression, and restored the telocyte markers CD117/c-kit and PDGFα. Ex can mitigate Dox-induced cardiotoxicity by acting as an anti-inflammatory, antioxidant, antiapoptotic, and antifibrotic agents, restoring telocytes and modulating epithelial mesenchymal transition. RESEARCH HIGHLIGHTS: Exosomes exhibit positive expression for CD90 and CD105 whereas showing -ve expression for CD 34 by flow cytometry. Exosomes restore the immunohistochemical expression of the telocytes markers CD117/c-kit and PDGFα. Exosomes alleviate myocardial apoptosis, oxidative stress and fibrosis.

Leflunomide-induced cardiac injury in adult male mice and bioinformatic approach identifying Nrf2/NF-κb signaling interplay

Leflunomide (LFND) is an immunosuppressive and immunomodulatory disease-modifying antirheumatic drug (DMARD) that was approved for treating rheumatoid arthritis. LFND-induced cardiotoxicity was not fully investigated since its approval. We investigated the cardiac injury in male mice and identified the role of nuclear factor erythroid 2-related factor 2/nuclear factor-κ B (Nrf2/NF-κB) signaling. Male albino mice were assigned into five groups as control, vehicle, and LFND (2.5, 5, and 10 mg/kg). We investigated cardiac enzymes, histopathology, and the mRNA expression of Nrf2, NF-κB, BAX, and tumor necrosis factor-α (TNF-α). The bioinformatic study identified the interaction between LFND and Nrf2/NF-κB signaling; this was confirmed by amelioration in mRNA expression (0.5- to 0.34-fold decrease in Nrf2 and 2.6- to 4.61-fold increases in NF-κB genes) and increased (1.76- and 2.625-fold) serum creatine kinase (CK) and 1.38- and 2.33-fold increases in creatine kinase-MB (CK-MB). Histopathological results confirmed the dose-dependent effects of LFND on cardiac muscle structure in the form of cytoplasmic, nuclear, and vascular changes in addition to increased collagen deposits and apoptosis which were increased compared to controls especially with LFND 10 mg/kg. The current study elicits the dose-dependent cardiac injury induced by LFND administration and highlights, for the first time, dysregulation in Nrf2/NF-κB signaling.

An update of the molecular mechanisms underlying anthracycline induced cardiotoxicity

Anthracycline drugs mainly include doxorubicin, epirubicin, pirarubicin, and aclamycin, which are widely used to treat a variety of malignant tumors, such as breast cancer, gastrointestinal tumors, lymphoma, etc. With the accumulation of anthracycline drugs in the body, they can induce serious heart damage, limiting their clinical application. The mechanism by which anthracycline drugs cause cardiotoxicity is not yet clear. This review provides an overview of the different types of cardiac damage induced by anthracycline-class drugs and delves into the molecular mechanisms behind these injuries. Cardiac damage primarily involves alterations in myocardial cell function and pathological cell death, encompassing mitochondrial dysfunction, topoisomerase inhibition, disruptions in iron ion metabolism, myofibril degradation, and oxidative stress. Mechanisms of uptake and transport in anthracycline-induced cardiotoxicity are emphasized, as well as the role and breakthroughs of iPSC in cardiotoxicity studies. Selected novel cardioprotective therapies and mechanisms are updated. Mechanisms and protective strategies associated with anthracycline cardiotoxicity in animal experiments are examined, and the definition of drug damage in humans and animal models is discussed. Understanding these molecular mechanisms is of paramount importance in mitigating anthracycline-induced cardiac toxicity and guiding the development of safer approaches in cancer treatment.

Prevention and treatment of anthracycline-induced cardiotoxicity: A bibliometric analysis of the years 2000-2023

Aims

This study aimed to evaluate the global research trend in the prevention and treatment of cardiotoxicity caused by anthracyclines from 2000 to 2023, and to explore international cooperation, research hotspots, and frontier trends.

Methods

The articles on the prevention and treatment of anthracycline-induced cardiotoxicity published from 2000 to 2023 were searched by Web of Science. The bibliometrics software CiteSpace was used for visual analysis of countries, institutions, journals, authors, cited authors, cited references, and keywords.

Results

This study analyzed the current status of global research on the prevention and treatment of cardiotoxicity caused by anthracyclines. A total of 3,669 papers were searched and 851 studies were included. The number of publications increased gradually throughout the years. Cardiovascular Toxicology (15) is the journal with the most publications. Circulation (547) ranked first among cited journals. In this field, the country with the most publications is the United States (229), and the institution with the most publications is Charles Univ Prague (18). In the analysis of the authors, Tomas S (10) ranked first. Cardinale D (262) ranked first among cited authors. In the ranking of cited literature frequency, the article ranked first is "Early detection of anthracycline cardiotoxicity and improvement with heart failure therapy" (121). The keywords "heart failure" (215) and "oxidative stress" (212) were the most frequent. "Enalapril", "inflammation", "cell death", "NF-κB" and "Nrf2" were the advanced research contents in 2019-2023.

Conclusions

This study provided valuable information for cardio-oncology researchers to identify potential collaborators and institutions, discover hot topics, and explore new research directions. The prevention and treatment of anthracycline-induced cardiotoxicity focuses on early detection and timely treatment. The results of the current clinical studies on the treatment of anthracycline-induced cardiotoxicity are contradictory, and more studies are needed to provide more reliable clinical evidence in the future.

Novel molecular mechanisms of doxorubicin cardiotoxicity: latest leading-edge advances and clinical implications

Doxorubicin (Dox) is among the most widely used cancer chemotherapeutic drugs. The clinical use of Dox is, however, limited due to its cardiotoxicity. Studies over the past several decades have suggested various mechanisms of Dox-induced cardiotoxicity (DIC). Among them are oxidative stress, topoisomerase inhibition, and mitochondrial damage. Several novel molecular targets and signaling pathways underlying DIC have emerged over the past few years. The most notable advances include discovery of ferroptosis as a major form of cell death in Dox cytotoxicity, and elucidation of the involvement of cardiogenetics and regulatory RNAs as well as multiple other targets in DIC. In this review, we discuss these advances, focusing on latest cutting-edge research discoveries from mechanistic studies reported in influential journals rather than surveying all research studies available in the literature.

Pharmacological activation of GPX4 ameliorates doxorubicin-induced cardiomyopathy

Due to the cardiotoxicity of doxorubicin (DOX), its clinical application is limited. Lipid peroxidation caused by excessive ferrous iron is believed to be a key molecular mechanism of DOX-induced cardiomyopathy (DIC). Dexrazoxane (DXZ), an iron chelator, is the only drug approved by the FDA for reducing DIC, but it has many side effects and cannot be used as a preventive drug in clinical practice. Single-nucleus RNA sequencing (snRNA-seq) analysis identified myocardial and epithelial cells that are susceptible to DOX-induced ferroptosis. The glutathione peroxidase 4 (GPX4) activator selenomethione (SeMet) significantly reduced polyunsaturated fatty acids (PUFAs) and oxidized lipid levels in vitro. Consistently, SeMet significantly decreased DOX-induced lipid peroxidation in H9C2 cells and mortality in C57BL/6 mice compared to DXZ, ferrostatin-1, and normal saline. SeMet can effectively reduce serum markers of cardiac injury in C57BL/6 mice and breast cancer patients. Depletion of the GPX4 gene in C57BL/6 mice resulted in an increase in polyunsaturated fatty acid (PUFA) levels and eliminated the protective effect of SeMet against DIC. Notably, SeMet exerted antitumor effects on breast cancer models with DOX while providing cardiac protection for the same animal without detectable toxicities. These findings suggest that pharmacological activation of GPX4 is a valuable and promising strategy for preventing the cardiotoxicity of doxorubicin.

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.

A review of chemotherapeutic drugs-induced arrhythmia and potential intervention with traditional Chinese medicines

Significant advances in chemotherapy drugs have reduced mortality in patients with malignant tumors. However, chemotherapy-related cardiotoxicity increases the morbidity and mortality of patients, and has become the second leading cause of death after tumor recurrence, which has received more and more attention in recent years. Arrhythmia is one of the common types of chemotherapy-induced cardiotoxicity, and has become a new risk related to chemotherapy treatment, which seriously affects the therapeutic outcome in patients. Traditional Chinese medicine has experienced thousands of years of clinical practice in China, and has accumulated a wealth of medical theories and treatment formulas, which has unique advantages in the prevention and treatment of malignant diseases. Traditional Chinese medicine may reduce the arrhythmic toxicity caused by chemotherapy without affecting the anti-cancer effect. This paper mainly discussed the types and pathogenesis of secondary chemotherapeutic drug-induced arrhythmia (CDIA), and summarized the studies on Chinese medicine compounds, Chinese medicine Combination Formula and Chinese medicine injection that may be beneficial in intervention with secondary CDIA including atrial fibrillation, ventricular arrhythmia and sinus bradycardia, in order to provide reference for clinical prevention and treatment of chemotherapy-induced arrhythmias.

The Role of Nrf2 and Inflammation on the Dissimilar Cardiotoxicity of Doxorubicin in Two-Time Points: a Cardio-Oncology In Vivo Study Through Time

Doxorubicin (DOX) is a topoisomerase II inhibitor used in cancer therapy. Despite its efficacy, DOX causes serious adverse effects, such as short- and long-term cardiotoxicity. This work aimed to assess the short- and long-term cardiotoxicity of DOX and the role of inflammation and antioxidant defenses on that cardiotoxicity in a mice model. Adult CD-1 male mice received a cumulative dose of 9.0 mg/kg of DOX (2 biweekly intraperitoneal injections (ip), for 3 weeks). One week (1W) or 5 months (5M) after the last DOX administration, the heart was collected. One week after DOX, a significant increase in p62, tumor necrosis factor receptor (TNFR) 2, glutathione peroxidase 1, catalase, inducible nitric oxide synthase (iNOS) cardiac expression, and a trend towards an increase in interleukin (IL)-6, TNFR1, and B-cell lymphoma 2 associated X (Bax) expression was observed. Moreover, DOX induced a decrease on nuclear factor erythroid-2 related factor 2 (Nrf2) cardiac expression. In both 1W and 5M, DOX led to a high density of infiltrating M1 macrophages, but only the 1W-DOX group had a significantly higher number of nuclear factor κB (NF-κB) p65 immunopositive cells. As late effects (5M), an increase in Nrf2, myeloperoxidase, IL-33, tumor necrosis factor-α (TNF-α), superoxide dismutase 2 (SOD2) expression, and a trend towards increased catalase expression were observed. Moreover, B-cell lymphoma 2 (Bcl-2), cyclooxygenase-2 (COX-2), and carbonylated proteins expression decreased, and a trend towards decreased p38 mitogen-activated protein kinase (MAPK) expression were seen. Our study demonstrated that DOX induces adverse outcome pathways related to inflammation and oxidative stress, although activating different time-dependent response mechanisms.

Shikonin alleviates doxorubicin-induced cardiotoxicity via Mst1/Nrf2 pathway in mice

Doxorubicin (DOX) is a popular and potent anticancer drug, but its cardiotoxicity limits its clinical application. Shikonin has a wide range of biological functions, including antioxidant and anti-inflammatory effects. The aim of this study was to investigate the effects of shikonin on DOX-induced cardiac injury and to identify the underlying mechanisms. Mice receiving shikonin showed reduced cardiac injury response and enhanced cardiac function after DOX administration. Shikonin significantly attenuated DOX-induced oxidative damage, inflammation accumulation and cardiomyocyte apoptosis. Shikonin protects against DOX-induced cardiac injury by inhibiting Mammalian sterile 20-like kinase 1 (Mst1) and oxidative stress and activating the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. In conclusion, shikonin alleviates DOX-induced cardiotoxicity by inhibiting Mst1 and activating Nrf2. Shikonin may be used to treat DOX-induced cardiac injury.

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.

Emodin ameliorates doxorubicin-induced cardiotoxicity by inhibiting ferroptosis through the remodeling of gut microbiota composition

The relationship between gut microbiota and doxorubicin-induced cardiotoxicity (DIC) is becoming increasingly clear. Emodin (EMO), a naturally occurring anthraquinone, exerts cardioprotective effects and plays a protective role by regulating gut microbiota composition. Therefore, the protective effect of EMO against DIC injury and its underlying mechanisms are worth investigating. In this study, we analyzed the differences in the gut microbiota in recipient mice transplanted with different flora using 16S-rDNA sequencing, analyzed the differences in serum metabolites among groups of mice using a nontargeted gas chromatography-mass spectrometry coupling system, and assessed cardiac function based on cardiac morphological staining, cardiac injury markers, and ferroptosis indicator assays. We found EMO ameliorated DIC and ferroptosis, as evidenced by decreased myocardial fibrosis, cardiomyocyte hypertrophy, and myocardial disorganization; improved ferroptosis indicators; and the maintenance of normal mitochondrial morphology. The protective effect of EMO was eliminated by the scavenging effect of antibiotics on the gut microbiota. Through fecal microbiota transplantation (FMT), we found that EMO restored the gut microbiota disrupted by doxorubicin (DOX) to near-normal levels. This was evidenced by an increased proportion of Bacteroidota and a decreased proportion of Verrucomicrobiota. FMT resulted in changes in the composition of serum metabolites. Mice transplanted with EMO-improved gut microbiota showed better cardiac function and ferroptosis indices; however, these beneficial effects were not observed in Nrf2 (Nfe2l2)-/- mice. Overall, EMO exerted a protective effect against DIC by attenuating ferroptosis, and the above effects occurred by remodeling the composition of gut microbiota perturbed by DOX and required Nrf2 mediation.NEW & NOTEWORTHY This study demonstrated for the first time the protective effect of emodin against DIC and verified by FMT that its cardioprotective effect was achieved by remodeling gut microbiota composition, resulting in attenuation of ferroptosis. Furthermore, we demonstrated that these effects were mediated by the redox-related gene Nrf2.

Galangin attenuates doxorubicin-induced cardiotoxicity via activating nuclear factor erythroid 2-related factor 2/heme oxygenase 1 signaling pathway to suppress oxidative stress and inflammation

Doxorubicin (DOX) has aroused contradiction between its potent anti-tumor capacity and severe cardiotoxicity. Galangin (Gal) possesses antioxidant, anti-inflammatory, and antiapoptotic activities. We aimed to explore the role and underlying mechanisms of Gal on DOX-induced cardiotoxicity. Mice were intraperitoneally injected with DOX (3 mg/kg, every 2 days for 2 weeks) to generate cardiotoxicity model and Gal (15 mg/kg, 2 weeks) was co-administered via gavage daily. Nuclear factor erythroid 2-related factor 2 (Nrf2) specific inhibitor, ML385, was employed to explore the underlying mechanisms. Compared to DOX-insulted mice, Gal effectively improved cardiac dysfunction and ameliorated myocardial damage. DOX-induced increase of reactive oxygen species, malondialdehyde, and NADPH oxidase activity and downregulation of superoxide dismutase (SOD) activity were blunted by Gal. Gal also markedly blocked increase of IL-1β, IL-6, and TNF-α in DOX-insulted heart. Mechanistically, Gal reversed DOX-induced downregulation of Nrf2, HO-1, and promoted nuclear translocation of Nrf2. ML385 markedly blunted the cardioprotective effects of Gal, as well as inhibitive effects on oxidative stress and inflammation. Gal ameliorates DOX-induced cardiotoxicity by suppressing oxidative stress and inflammation via activating Nrf2/HO-1 signaling pathway. Gal may serve as a promising cardioprotective agent for DOX-induced cardiotoxicity.

Activation of the Nrf-2/HO-1 signalling axis can alleviate metabolic syndrome in cardiovascular disease

Background: Cardiovascular disease (CVD) is widely observed in modern society. CVDs are responsible for the majority of fatalities, with heart attacks and strokes accounting for approximately 80% of these cases. Furthermore, a significant proportion of these deaths, precisely one-third, occurs in individuals under 70. Metabolic syndrome encompasses a range of diseases characterized by various physiological dysfunctions. These include increased inflammation in adipose tissue, enhanced cholesterol synthesis in the liver, impaired insulin secretion, insulin resistance, compromised vascular tone and integrity, endothelial dysfunction, and atheroma formation. These factors contribute to the development of metabolic disorders and significantly increase the likelihood of experiencing cardiovascular complications.Method: We selected studies that proposed hypotheses regarding metabolic disease syndrome and cardiovascular disease (CVD) and the role of Nrf2/HO-1 and factor regulation in CVD research investigations based on our searches of Medline and PubMed.Results: A total of 118 articles were included in the review, 16 of which exclusively addressed hypotheses about the role of Nrf2 on Glucose regulation, while 16 involved Cholesterol regulation. Likewise, 14 references were used to prove the importance of mitochondria on Nrf2. Multiple studies have provided evidence suggesting the involvement of Nrf2/HO-1 in various physiological processes, including metabolism and immune response. A total of 48 research articles and reviews have been used to highlight the role of metabolic syndrome and CVD.Conclusion: This review provides an overview of the literature on Nrf2/HO-1 and its role in metabolic disease syndrome and CVD.

Anthracycline cardiotoxicity is exacerbated by global p38β genetic ablation in a sexually dimorphic manner but unaltered by cardiomyocyte-specific p38α loss

Severe cardiotoxic effects limit the efficacy of doxorubicin (DOX) as a chemotherapeutic agent. Activation of intracellular stress signaling networks, including p38 mitogen-activated protein kinase (MAPK), has been implicated in DOX-induced cardiotoxicity (DIC). However, the roles of the individual p38 isoforms in DIC remain incompletely elucidated. We recently reported that global p38δ deletion protected female but not male mice from DIC, whereas global p38γ deletion did not significantly modulate it. Here we studied the in vivo roles of p38α and p38β in acute DIC. Male and female mice with cardiomyocyte-specific deletion of p38α or global deletion of p38β and their wild-type counterparts were injected with DOX. Survival and health were tracked for 10 days postinjection. Cardiac function was assessed by echocardiography and electrocardiography and fibrosis by Picrosirius red staining. Expression and activation of signaling proteins and inflammatory markers were measured by Western blot, phosphorylation array, and chemokine/cytokine array. Global p38β deletion significantly aggravated DIC and worsened cardiac electrical and mechanical function deterioration in female mice. Mechanistically, DIC in p38β-null female mice correlated with increased autophagy, sustained hyperactivation of proapoptotic JNK signaling, as well as remodeling of a myocardial inflammatory environment. In contrast, cardiomyocyte-specific deletion of p38α improved survival of DOX30-treated male mice 5 days posttreatment but did not influence cardiac function in DOX-treated male or female mice. Our data highlight the sex- and isoform-specific roles of p38α and p38β MAPKs in DOX-induced cardiac injury and suggest a novel in vivo function of p38β in protecting female mice from DIC.NEW & NOTEWORTHY We show that p38α and p38β have distinct in vivo functions in a murine model of acute DIC. Specifically, although conditional cardiomyocyte-specific p38α deletion exhibited mild cardioprotective effects in male mice, p38β deletion exacerbated the DOX cardiotoxicity in female mice. Our findings caution against employing pyridinyl imidazole inhibitors that target both p38α and p38β isoforms as a cardioprotective strategy against DIC. Such an approach could have undesirable sex-dependent effects, including attenuating p38β-dependent cardioprotection in females.

Development and validation of risk prediction and neural network models for dilated cardiomyopathy based on WGCNA

Background

Dilated cardiomyopathy (DCM) is a progressive heart condition characterized by ventricular dilatation and impaired myocardial contractility with a high mortality rate. The molecular characterization of DCM has not been determined yet. Therefore, it is crucial to discover potential biomarkers and therapeutic options for DCM.

Methods

The hub genes for the DCM were screened using Weighted Gene Co-expression Network Analysis (WGCNA) and three different algorithms in Cytoscape. These genes were then validated in a mouse model of doxorubicin (DOX)-induced DCM. Based on the validated hub genes, a prediction model and a neural network model were constructed and validated in a separate dataset. Finally, we assessed the diagnostic efficiency of hub genes and their relationship with immune cells.

Results

A total of eight hub genes were identified. Using RT-qPCR, we validated that the expression levels of five key genes (ASPN, MFAP4, PODN, HTRA1, and FAP) were considerably higher in DCM mice compared to normal mice, and this was consistent with the microarray results. Additionally, the risk prediction and neural network models constructed from these genes showed good accuracy and sensitivity in both the combined and validation datasets. These genes also demonstrated better diagnostic power, with AUC greater than 0.7 in both the combined and validation datasets. Immune cell infiltration analysis revealed differences in the abundance of most immune cells between DCM and normal samples.

Conclusion

The current findings indicate an underlying association between DCM and these key genes, which could serve as potential biomarkers for diagnosing and treating DCM.

Impact of Cerium Oxide Nanoparticles on Metabolic, Apoptotic, Autophagic and Antioxidant Changes in Doxorubicin-Induced Cardiomyopathy: Possible Underlying Mechanisms

Background

In the current study, the effects of cerium oxide nanoparticles (nanocerium; NC) on doxorubicin (DOX)-induced cardiomyopathy and its possible underlying mechanisms were addressed.

Methods

32 adult male rats were allocated into 4 groups; i) control group, ii) NC group; rats received NC (0.2 mg/kg, i.p., daily), iii) DOX group; rats received DOX 4 mg/kg (2 injections with a 14-day interval), and iv) DOX+NC group as DOX but rats received NC. At the end of the experiment, ECG and ECHO recordings and assessments of the levels of cardiac enzymes (CK-MB, LDH), and myocardial oxidative stress (MDA, catalase, and GSH), the expression of LC3 and beclin1 (markers of autophagy), caspase3 (marker of apoptosis) by immunohistochemistry, the expression of acetyl-CoA carboxylase alpha (ACCA) by PCR, and 5'adenosine monophosphate-activated protein kinase (AMPK) levels in the heart tissues were performed.

Results

The DOX group displayed a prolonged corrected QT interval, an increase in cardiac enzymes (CK-MB and LDH), myocardial oxidative stress (high MDA with low catalase and GSH), expression of ACCA, caspase-3, beclin1, and LC3 in myocardial tissues, with reduction in myocardial AMPK levels, and myocardial contractility (low ejection fraction, and fractional shortening). On the other hand, administration of NC with DOX resulted in significant improvement of all studied parameters.

Conclusion

NC offers a cardioprotective effect against DOX-induced cardiomyopathy. This effect might be due to its antioxidant and antiapoptotic effects as well as to the modulation of autophagy and metabolic dysfunctions induced by DOX in the heart tissues.

Sheng-Mai-Yin inhibits doxorubicin-induced ferroptosis and cardiotoxicity through regulation of Hmox1

Doxorubicin (DOX) is a potent chemotherapeutic drug used for treating various cancers. However, its clinical use is limited due to its severe cardiotoxicity, which often results in high mortality rates. Sheng-Mai-Yin (SMY), a Traditional Chinese medicine (TCM) prescription, has been reported to exert a cardioprotective effect in various cardiovascular diseases, including DOX-induced cardiotoxicity (DIC). This study aimed to provide novel insights into the underlying cardioprotective mechanism of SMY. SMY, composed of Codonopsis pilosula (Franch.), Ophiopogon japonicus (Thunb.), and Schisandra chinensis (Turcz.) at a ratio of 3:2:1, was intragastrically administered to male C57BL/6 mice for five days prior to the intraperitoneal injection of mitoTEMPO. One day later, DOX was intraperitoneally injected. Hematoxylin-eosin staining and Sirius red staining were carried out to estimate the pharmacological effect of SMY on cardiotoxicity. Mitochondrial function and ferroptosis biomarkers were also examined. AAV was utilized to overexpress Hmox1 to confirm whether Hmox1-mediated ferroptosis is associated with the cardioprotective effect of SMY on DOX-induced cardiotoxicity. The findings revealed that SMY therapy reduced the number of damaged cardiomyocytes. SMY therapy also reversed the inductions of cardiac MDA, serum MDA, LDH, and CK-MB contents, which dramatically decreased nonheme iron levels. In the meantime, SMY corrected the changes to ferroptosis indices brought on by DOX stimulation. Additionally, Hmox1 overexpression prevented SMY's ability to reverse cardiotoxicity. Our results showed that SMY effectively restrained lipid oxidation, reduced iron overload, and inhibited DOX-induced ferroptosis and cardiotoxicity, possibly via the mediation of Hmox1.

Acrocomia aculeata associated with doxorubicin: cardioprotection and anticancer activity

Doxorubicin (Dox) is a chemotherapeutic agent widely used in the clinic, whose side effects include cardiotoxicity, associated with decreased antioxidant defenses and increased oxidative stress. The association of Dox with natural antioxidants can extend its use if not interfering with its pharmacological potential. In this study, we aimed to understand the effects and mechanisms of the aqueous extract of Acrocomia aculeata leaves (EA-Aa) in cancer cells and the co-treatment with Dox, in in vitro and in vivo models. It was found that EA-Aa showed a relevant decrease in the viability of cancer cells (K562 and MCF-7) and increased apoptosis and death. The Dox cytotoxic effect in co-treatment with EA-Aa was increased in cancer cells. The therapeutic association also promoted a change in cell death, leading to a higher rate of apoptosis compared to the Dox group, which induced necrosis. In addition, in non-cancer cells, EA-Aa enhanced red blood cell (RBC) redox state with lower hemolysis and malondialdehyde (MDA) content and had no in vitro nor in vivo toxicity. Furthermore, EA-Aa showed antioxidant protection against Dox-induced cytotoxicity in H9c2 cells (cardiomyoblast), partially mediated by the NRF2 pathway. In vivo, EA-Aa treatment showed a relevant decrease in MDA levels in the heart, kidney, and brain, evaluated in C57Bl/6 mice induced to cardiotoxicity by Dox. Together, our results proved the effectiveness of EA-Aa in potentiating Dox anticancer effects, with antioxidant and cardioprotective activity, suggesting EA-Aa as a potential Dox pharmacological adjuvant.

Irisin protects against doxorubicin-induced cardiotoxicity by improving AMPK-Nrf2 dependent mitochondrial fusion and strengthening endogenous anti-oxidant defense mechanisms

Irisin, a new exercise-mediated myokine, plays an important role in cardiovascular diseases by regulating cell energy metabolism. The induction of mitochondrial dysfunction and oxidative stress are the crucial mechanisms involved in doxorubicin-induced cardiomyocyte damage and cardiac dysfunction, but the mitochondria-dependent protective mechanisms of irisin in DOX-impaired cardiomyocytes are poorly understood. In this study, we exposed mouse-FNDC5 (irisin-precursor)-knockout, FNDC5 transgenic mice and their WT littermates, as well as cultured neonatal rat cardiomyocytes to DOX at a dosage of 4 mg/kg (once a week for 4 weeks) in vivo and 2 μM in vitro, respectively, then investigated how irisin alleviated DOX-induced oxidative stress and myocardial injury. Irisin knockout worsened, while irisin overexpression attenuated DOX-induced mortality, body weight loss, myocardial atrophy, damage and oxidative stress, cardiac remodeling and dysfunction in mice. Exogenous irisin supplementation (20 nM) also relieved these DOX-induced damage in cardiomyocytes. Intriguingly, irisin activated AMPK-Nrf2 signaling axis, and then up-regulated the transcription and protein expression of the downstream target genes of Nrf2, including mitochondrial fusion-related genes (mitofusin 1/2 and Optic Atrophy Type 1) and endogenous anti-oxidant genes, to promote mitochondrial fusion, improve mitochondrial dynamics and mitochondrial function, and reduced oxidative stress damage in DOX-induced cardiomyocytes. These results suggest that irisin protects the hearts from DOX-induced cardiotoxicity by improving mitochondrial dynamics and strengthening the endogenous anti-oxidant system through an AMPK-Nrf2 axis dependent manner, thus reducing DOX-induced oxidative stress injury in cardiomyocytes.

Nrf2: a dark horse in doxorubicin-induced cardiotoxicity

Being a broad-spectrum anticancer drug, doxorubicin is indispensable for clinical treatment. Unexpectedly, its cardiotoxic side effects have proven to be a formidable obstacle. Numerous studies are currently devoted to elucidating the pathological mechanisms underlying doxorubicin-induced cardiotoxicity. Nrf2 has always played a crucial role in oxidative stress, but numerous studies have demonstrated that it also plays a vital part in pathological mechanisms like cell death and inflammation. Numerous studies on the pathological mechanisms associated with doxorubicin-induced cardiotoxicity demonstrate this. Several clinical drugs, natural and synthetic compounds, as well as small molecule RNAs have been demonstrated to prevent doxorubicin-induced cardiotoxicity by activating Nrf2. Consequently, this study emphasizes the introduction of Nrf2, discusses the role of Nrf2 in doxorubicin-induced cardiotoxicity, and concludes with a summary of the therapeutic modalities targeting Nrf2 to ameliorate doxorubicin-induced cardiotoxicity, highlighting the potential value of Nrf2 in doxorubicin-induced cardiotoxicity.

Novel pterostilbene derivatives ameliorate heart failure by reducing oxidative stress and inflammation through regulating Nrf2/NF-κB signaling pathway

Pterostilbene is a demethylated resveratrol derivative with attractive anti-inflammatory, anti-tumor and anti-oxidative stress activities. However, the clinical use of pterostilbene is limited by its poor selectivity and druggability. Heart failure is a leading cause of morbidity and mortality worldwide, which is closely related to enhanced oxidative stress and inflammation. There is an urgent need for new effective therapeutic drugs that can reduce oxidative stress and inflammatory responses. Therefore, we designed and synthesized a series of novel pterostilbene chalcone and dihydropyrazole derivatives with antioxidant and anti-inflammatory activities by the molecular hybridization strategy. The preliminary anti-inflammatory activities and structure-activity relationships of these compounds were evaluated by nitric oxide (NO) inhibitory activity in lipopolysaccharide (LPS)-treated RAW264.7 cells, and compound E1 exhibited the most potent anti-inflammatory activities. Furthermore, pretreatment with compound E1 decreased reactive oxygen species (ROS) generation both in RAW264.7 and H9C2 cells by increasing the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), as well as downstream antioxidant enzymes superoxide dismutase 1 (SOD1), catalase (CAT) and glutathione peroxidase 1 (GPX1). In addition, compound E1 also significantly inhibited LPS or doxorubicin (DOX)-induced inflammation in both RAW264.7 and H9C2 cells through reducing the expression of inflammatory cytokines by inhibiting nuclear factor-κB (NF-κB) signaling pathway. Moreover, we found that compound E1 improved DOX-induced heart failure by inhibiting inflammation and oxidative stress in mouse model, which is mediated by the potential of antioxidant and anti-inflammatory activities. In conclusion, this study demonstrated the novel pterostilbene dihydropyrazole derivative E1 was identified as a promising agent for heart failure treatment.

Doxorubicin and Quercetin Double Loading in Modified MCM-41 Lowered Cardiotoxicity in H9c2 Cardioblast Cells In Vitro

BACKGROUND

One of the therapeutic limitations of the use of doxorubicin (DOX) as an anticancer drug is its cardiotoxicity. Its hydrophilicity also causes difficulties in achieving sustained release. The simultaneous delivery with the well-known natural antioxidant quercetin could ameliorate its cardiotoxicity. Thus, the main aim of this work is to study the potential of carboxylated and non-carboxylated mesoporous silica MCM-41 nanoparticles for double loading of the hydrophilic doxorubicin hydrochloride and hydrophobic quercetin (Q) in one nanocarrier with a modified release pattern to reduce the cardiotoxic side effects of doxorubicin in vitro.

METHODS

The methods included the modification of MCM-41, single and double loading of modified and non-modified MCM-41, physicochemical characterization, in vitro release tests and kinetic study, and in vitro cell viability studies.

RESULTS

Doxorubicin and quercetin were successfully double-loaded with encapsulation efficiency (EE) of 43 ± 4.1% and 37 ± 4.5%, respectively, in native MCM-41. The post-synthetic carboxylation led to 49 ± 4.3% EE (DOX) and 36 ± 4.0% (Q) and double lowering of the cardiotoxicity on H9c2 (IC₅₀ = 5.96 µm). Sustained release profiles over 72 h were achieved.

CONCLUSIONS

A successful procedure was proposed for the efficient double loading of a hydrophilic drug and a hydrophobic drug. The carboxy-modified double-loaded nanosystems demonstrate a decreased in vitro cardiotoxicity of doxorubicin and can be considered as a potential chemotherapeutic formulation.

The Potential of Cylindromatosis (CYLD) as a Therapeutic Target in Oxidative Stress-Associated Pathologies: A Comprehensive Evaluation

Oxidative stress (OS) arises as a consequence of an imbalance between the formation of reactive oxygen species (ROS) and the capacity of antioxidant defense mechanisms to neutralize them. Excessive ROS production can lead to the damage of critical biomolecules, such as lipids, proteins, and DNA, ultimately contributing to the onset and progression of a multitude of diseases, including atherosclerosis, chronic obstructive pulmonary disease, Alzheimer's disease, and cancer. Cylindromatosis (CYLD), initially identified as a gene linked to familial cylindromatosis, has a well-established and increasingly well-characterized function in tumor inhibition and anti-inflammatory processes. Nevertheless, burgeoning evidence suggests that CYLD, as a conserved deubiquitination enzyme, also plays a pivotal role in various key signaling pathways and is implicated in the pathogenesis of numerous diseases driven by oxidative stress. In this review, we systematically examine the current research on the function and pathogenesis of CYLD in diseases instigated by oxidative stress. Therapeutic interventions targeting CYLD may hold significant promise for the treatment and management of oxidative stress-induced human diseases.

Cellular Mechanisms Mediating Exercise-Induced Protection against Cardiotoxic Anthracycline Cancer Therapy

Anthracyclines such as doxorubicin are widely used chemotherapy drugs. A common side effect of anthracycline therapy is cardiotoxicity, which can compromise heart function and lead to dilated cardiomyopathy and heart failure. Dexrazoxane and heart failure medications (i.e., beta blockers and drugs targeting the renin-angiotensin system) are prescribed for the primary prevention of cancer therapy-related cardiotoxicity and for the management of cardiac dysfunction and symptoms if they arise during chemotherapy. However, there is a clear need for new therapies to combat the cardiotoxic effects of cancer drugs. Exercise is a cardioprotective stimulus that has recently been shown to improve heart function and prevent functional disability in breast cancer patients undergoing anthracycline chemotherapy. Evidence from preclinical studies supports the use of exercise training to prevent or attenuate the damaging effects of anthracyclines on the cardiovascular system. In this review, we summarise findings from experimental models which provide insight into cellular mechanisms by which exercise may protect the heart from anthracycline-mediated damage, and identify knowledge gaps that require further investigation. Improved understanding of the mechanisms by which exercise protects the heart from anthracyclines may lead to the development of novel therapies to treat cancer therapy-related cardiotoxicity.

Chlorogenic Acid Attenuates Doxorubicin-Induced Oxidative Stress and Markers of Apoptosis in Cardiomyocytes via Nrf2/HO-1 and Dityrosine Signaling

(1) Background: Doxorubicin (DOX) is extensively used for cancer treatments; however, its clinical application is limited because of its cardiotoxic adverse effects. A combination of DOX and agents with cardioprotective properties is an effective strategy to ameliorate DOX-related cardiotoxicity. Polyphenolic compounds are ideal for the investigation of novel cardioprotective agents. Chlorogenic acid (CGA), an essential dietary polyphenol found in plants, has been previously reported to exert antioxidant, cardioprotective, and antiapoptotic properties. The current research evaluated CGA's in vivo cardioprotective properties in DOX-induced cardiotoxicity and the probable mechanisms underlying this protection. (2) Methods: CGA's cardioprotective properties were investigated in rats that were treated with CGA (100 mg/kg, p.o.) for fourteen days. The experimental model of cardiotoxicity was induced with a single intraperitoneal (15 mg/kg i.p.) injection of DOX on the 10th day. (3) Results: Treatment with CGA significantly improved the DOX-caused altered cardiac damage markers (LDH, CK-MB, and cTn-T), and a marked improvement in cardiac histopathological features accompanied this. DOX downregulated the expression of Nrf2/HO-1 signaling pathways, and the CGA reversed this effect. Consistently, caspase-3, an apoptotic-related marker, and dityrosine expression were suppressed, while Nrf2 and HO-1 expressions were elevated in the cardiac tissues of DOX-treated rats after treatment with the CGA. Furthermore, the recovery was confirmed by the downregulation of 8-OHdG and dityrosine (DT) expressions in immunohistochemical findings. (4) Conclusions: CGA demonstrated a considerable cardioprotective effect against DOX-induced cardiotoxicity. One of the possible mechanisms for these protective properties was the upregulation of the Nrf2/HO-1-dependent pathway and the downregulation of DT, which may ameliorate oxidative stress and cardiomyocyte apoptosis. These findings suggest that CGA may be cardioprotective, particularly in patients receiving DOX-based chemotherapy.

Mitigation of Cardiovascular Disease and Toxicity through NRF2 Signalling

Cardiovascular toxicity and diseases are phenomena that have a vastly detrimental impact on morbidity and mortality. The pathophysiology driving the development of these conditions is multifactorial but commonly includes the perturbance of reactive oxygen species (ROS) signalling, iron homeostasis and mitochondrial bioenergetics. The transcription factor nuclear factor erythroid 2 (NFE2)-related factor 2 (NRF2), a master regulator of cytoprotective responses, drives the expression of genes that provide resistance to oxidative, electrophilic and xenobiotic stresses. Recent research has suggested that stimulation of the NRF2 signalling pathway can alleviate cardiotoxicity and hallmarks of cardiovascular disease progression. However, dysregulation of NRF2 dynamic responses can be severely impacted by ageing processes and off-target toxicity from clinical medicines including anthracycline chemotherapeutics, rendering cells of the cardiovascular system susceptible to toxicity and subsequent tissue dysfunction. This review addresses the current understanding of NRF2 mechanisms under homeostatic and cardiovascular pathophysiological conditions within the context of wider implications for this diverse transcription factor.

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.

Cell death regulation in myocardial toxicity induced by antineoplastic drugs

Homeostatic regulation of cardiomyocytes plays a critical role in maintaining normal physiological activity of cardiac tissue. Severe cardiotoxicity can lead to heart disease, including but not limited to arrhythmias, myocardial infarction and cardiac hypertrophy. In recent years, significant progress has been made in developing new therapies for cancer that have dramatically changed the treatment of several malignancies and continue to improve patient survival, but can also lead to serious cardiac adverse effects. Mitochondria are key organelles that maintain homeostasis in myocardial tissue and have been extensively involved in various cardiovascular disease episodes, including ischemic cardiomyopathy, heart failure and stroke. Several studies support that mitochondrial targeting is a major determinant of the cardiotoxic effects triggered by chemotherapeutic agents increasingly used in solid and hematologic tumors. This antineoplastic therapy-induced mitochondrial toxicity is due to different mechanisms, usually altering the mitochondrial respiratory chain, energy production and mitochondrial kinetics, or inducing mitochondrial oxidative/nitrosative stress, ultimately leading to cell death. This review focuses on recent advances in forms of cardiac cell death and related mechanisms of antineoplastic drug-induced cardiotoxicity, including autophagy, ferroptosis, apoptosis, pyroptosis, and necroptosis, explores and evaluates key proteins involved in cardiac cell death signaling, and presents recent advances in cardioprotective strategies for this disease. It aims to provide theoretical basis and targets for the prevention and treatment of pharmacological cardiotoxicity in clinical settings.

Sirt3 activates autophagy to prevent DOX-induced senescence by inactivating PI3K/AKT/mTOR pathway in A549 cells

Sirtuin 3 (Sirt3), a mitochondrial deacetylase, regulates mitochondrial redox homeostasis and autophagy and is involved in physiological and pathological processes such as aging, cellular metabolism, and tumorigenesis. We here investigate how Sirt3 regulates doxorubicin (DOX)-induced senescence in lung cancer A549 cells. Sirt3 greatly reduced DOX-induced upregulation of senescence marker proteins p53, p16, p21 and SA-β-Gal activity as well as ROS levels. Notably, Sirt3 reversed DOX-induced autophagic flux blockage, as shown by increased p62 degradation and LC3II/LC3I ratio. Importantly, the autophagy inhibitors 3-methyladenine (3-MA) and chloroquine (CQ) partially abolished the antioxidant stress and antiaging effects of Sirt3, while the autophagy activator rapamycin (Rap) potentiated these effects of Sirt3, demonstrating that autophagy mediates the anti-aging effects of Sirt3. Additionally, Sirt3 inhibited the DOX-induced activation of the phosphatidylinositol-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling pathway, which in turn activated autophagy. The PI3K inhibitor LY294002 promoted the antioxidant stress and antiaging effects of Sirt3, while the AKT activator SC-79 reversed these effects of Sirt3. Taken together, Sirt3 counteracts DOX-induced senescence by improving autophagic flux.

MicroRNAs in doxorubicin-induced cardiotoxicity: The DNA damage response

Doxorubicin (DOX) is a chemotherapeutic drug widely used for cancer treatment, but its use is limited by cardiotoxicity. Although free radicals from redox cycling and free cellular iron have been predominant as the suggested primary pathogenic mechanism, novel evidence has pointed to topoisomerase II inhibition and resultant genotoxic stress as the more fundamental mechanism. Recently, a growing list of microRNAs (miRNAs) has been implicated in DOX-induced cardiotoxicity (DIC). This review summarizes miRNAs reported in the recent literature in the context of DIC. A particular focus is given to miRNAs that regulate cellular responses downstream to DOX-induced DNA damage, especially p53 activation, pro-survival signaling pathway inhibition (e.g., AMPK, AKT, GATA-4, and sirtuin pathways), mitochondrial dysfunction, and ferroptosis. Since these pathways are potential targets for cardioprotection against DOX, an understanding of how miRNAs participate is necessary for developing future therapies.

NBP Relieves Cardiac Injury and Reduce Oxidative Stress and Cell Apoptosis in Heart Failure Mice by Activating Nrf2/HO-1/Ca2+-SERCA2a Axis

Although heart failure (HF) has become one of the most fatal diseases in the whole world, there are fewer drugs for its treatment. Therefore, we focused on the protective effect of Dl-3-n-butylphthalide (NBP) on myocardial injury and oxidative stress in heart failure mice and further investigated the relationship with the Nrf2/HO-1/Ca2+-SERCA2a axis. Methods. C57BL/6J mice were divided into the sham group (Sham), heart Failure model group (HF), HF + NBP group (HN), HN + Nrf2 inhibitor (HNM), HN + Calmodulin-dependent protein kinase II (CaMKII) antagonist, KN93 (HNK). The HF mice model was prepared using abdominal aorta ligation. Mice’s heart function was accessed by echocardiography. Hematoxylin-eosin staining and MASSON staining were used to identify myocardial injury; the cell apoptosis was determined by the TUNEL staining assay. The expression of oxidative stress-related proteins was detected by the ELISA assay. The reactive oxygen species and Nrf2 expression in heart tissue were observed with the immunofluorescence assay. SERCA2a, calmodulin, endoplasmic reticulum stress regulatory proteins, and Nrf2/HO-1 in mice’ heart tissues were measured using Western blotting. Results. Moreover, NBP could significantly promote heart failure mice’s heart function, relieve the injury and inhibit cell apoptosis. Meanwhile, it could reduce ERS injury of heart failure mice through increasing SERCA2a level and reducing Ca2+ influx. NBP was demonstrated to minimize CaMKII phosphorylation level and decrease cAMP-response element-binding protein phosphorylation level, suggesting NBP could also activate the Nrf2/HO-1 signaling pathway. Conclusions. We demonstrated that NPBs treatment promotes the cardiomyocyte’s ERS and alleviates myocardial injury in heart failure mice, related to stimulating the Nrf2/HO-1 signaling pathway, regulating Ca2+-SERCA2a, and reducing Ca2+ influx.

Exosomal thioredoxin-1 from hypoxic human umbilical cord mesenchymal stem cells inhibits ferroptosis in doxorubicin-induced cardiotoxicity via mTORC1 signaling

Doxorubicin (DOX), a clinical chemotherapeutic drug, is often annoyed by its cardiotoxicity which involves ferroptosis in its pathological progress. Human umbilical cord mesenchymal stem cells (HucMSCs)-derived exosomes (HucMSCs-Exo) are proven effective in treating cardiovascular diseases. This study aimed to compare the therapeutic effects between normoxic HucMSCs-Exo (Exo) and hypoxic HucMSCs-Exo (Hypo-Exo) on DOX-induced ferroptosis and explore the underlying mechanisms. An acute cardiotoxicity model was successfully constructed by administrating two doses intraperitoneal injections of DOX (25 mg/kg in total). Exo and Hypo-Exo were extracted by ultracentrifugation and characterized. Compared with Exo, Hypo-Exo and Ferrostatin-1 (Fer-1) exerted superior effects on inhibiting DOX-induced ferroptosis, as evidenced by decreasing malondialdehyde (MDA), iron content and increasing glutathione (GSH) level as well as ferroptosis-related genes expression including prostaglandin-endoperoxide synthase 2 (Ptgs2) mRNA level and glutathione peroxidase 4 (GPX4) protein level. Based on quantitative proteomics analysis, we found that thioredoxin1 (Trx1) was remarkably upregulated in Hypo-Exo and exhibited anti-ferroptosis activity via activating the mechanistic target of rapamycin complex 1 (mTORC1) in neonatal rat cardiomyocytes (NRCMs). Trx1 knockdown and rapamycin (an mTORC1 inhibitor) partially abolished the protective effects of Hypo-Exo. Furthermore, our data indicated that solute carrier family 7 member 11 (SLC7A11) was critical for GPX4 protein synthesis. In conclusion, Hypo-Exo exhibited a better suppression of ferroptosis in DOX-induced cardiotoxicity. Trx1-mediated mTORC1 activation is critical for the Hypo-Exo anti-ferroptosis process, which involves increased GPX4 protein synthesis and decreased iron overload. This study indicated that Hypo-Exo may present a potential strategy against ferroptosis in DOX-induced cardiotoxicity.

Natural compound glycyrrhetinic acid protects against doxorubicin-induced cardiotoxicity by activating the Nrf2/HO-1 signaling pathway

BACKGROUND

As one of the most classic antineoplastic agents, doxorubicin (Dox) is extensively used to treat a wide range of cancers. Nevertheless, the clinical outcomes of Dox-based therapies are severely hampered due to the significant cardiotoxicity. Glycyrrhetinic acid (GA) is the major biologically active compound of licorice, one of the most well-known food additives and medicinal plants in the world. We previously demonstrated that GA has the potential capability to protect mice from Dox-induced cardiac injuries. However, the underlying cardioprotective mechanism remains unexplored.

PURPOSE

To investigate the cardioprotective benefits of GA against Dox-induced cardiotoxicity and to elucidate its mechanisms of action.

STUDY DESIGN/METHODS

H9c2 cardiomyoblasts and AC16 cardiomyocytes were used as the cell models in vitro. A transgenic zebrafish model and a 4T1 mouse breast cancer model were applied to explore the cardioprotective effects of GA in vivo.

RESULTS

In vitro, GA inhibited Dox-induced cell death and LDH release in H9c2 and AC16 cells without affecting the anti-cancer effects of Dox. GA significantly alleviated Dox-induced ROS generation, mitochondrial dysfunction, and apoptosis in H9c2 cells. Moreover, GA abolished the expression of pro-apoptotic proteins and restored Nrf2/HO-1 signaling pathway in Dox-treated H9c2 cells. On the contrary, Nrf2 knockdown strongly abrogated the cardioprotective effects of GA on Dox-treated H9c2 cells. In vivo, GA attenuated Dox-induced cardiac dysfunction by restoring stroke volume, cardiac output, and fractional shortening in the transgenic zebrafish embryos. In a 4T1 mouse breast cancer model, GA dramatically prevented body weight loss, attenuated cardiac dysfunction, and prolonged survival rate in Dox-treated mice, without compromising Dox's anti-tumor efficacy. Consistently, GA attenuated oxidative injury, reduced cardiomyocytes apoptosis, and restored the expressions of Nrf2 and HO-1 in Dox-treated mouse hearts.

CONCLUSION

GA protects against Dox-induced cardiotoxicity by suppressing oxidative stress, mitochondrial dysfunction, and apoptosis via upregulating Nrf2/HO-1 signaling pathway. These findings could provide solid evidence to support the further development of GA as a feasible and safe adjuvant to Dox chemotherapy for overcoming Dox-induced cardiotoxicity.

Intracellular Polyphenol Wine Metabolites Oppose Oxidative Stress and Upregulate Nrf2/ARE Pathway

Moderate wine consumption has been associated with several benefits to human health due to its high polyphenol content. In this study, we investigated whether polyphenols contained in a particular red wine, rich in polyphenols, can pass the cell membrane and switch the oxidant/antioxidant balance toward an antioxidant pattern of THP-1 cells and human cardiomyocytes through a gene regulatory system. First, we identified which metabolite polyphenols present in red wine extract cross cell membranes and may be responsible for antioxidant effects. The results showed that the wine metabolites in treated cells belonged mainly to stilbenes, flavan-3-ols derivatives, and flavonoids. Other metabolites present in cells were not typical wine metabolites. Then, we found that red wine extract dose-dependently lowered reactive oxygen species (ROS) induced by tert-butyl hydroperoxide (TBHP) up to 50 ± 7% in both cell lines (p < 0.01). Furthermore, wine extract increased nuclear Nrf2 of about 35 ± 5% in both cell lines (p < 0.01) and counteracted its reduction induced by TBHP (p < 0.01). The rise in Nrf2 was paralleled by the increase in hemeoxygenase-1 and glutamate-cysteine ligase catalytic subunit gene expression (both mRNA and protein) (p < 0.01). These results could help explain the healthful activity of wine polyphenols within cells.

Emerging mitochondrial signaling mechanisms in cardio-oncology: beyond oxidative stress

Many anticancer therapies (CTx) have cardiotoxic side effects that limit their therapeutic potential and cause long-term cardiovascular complications in cancer survivors. This has given rise to the field of cardio-oncology, which recognizes the need for basic, translational, and clinical research focused on understanding the complex signaling events that drive CTx-induced cardiovascular toxicity. Several CTx agents cause mitochondrial damage in the form of mitochondrial DNA deletions, mutations, and suppression of respiratory function and ATP production. In this review, we provide a brief overview of the cardiovascular complications of clinically used CTx agents and discuss current knowledge of local and systemic secondary signaling events that arise in response to mitochondrial stress/damage. Mitochondrial oxidative stress has long been recognized as a contributor to CTx-induced cardiotoxicity; thus, we focus on emerging roles for mitochondria in epigenetic regulation, innate immunity, and signaling via noncoding RNAs and mitochondrial hormones. Because data exploring mitochondrial secondary signaling in the context of cardio-oncology are limited, we also draw upon clinical and preclinical studies, which have examined these pathways in other relevant pathologies.

PRMT4 promotes ferroptosis to aggravate doxorubicin-induced cardiomyopathy via inhibition of the Nrf2/GPX4 pathway

Doxorubicin (DOX), a commonly used antitumor agent, is often accompanied by its dosage-dependent cardiotoxicity, which incorporates ferroptosis in its pathogenesis. Protein arginine methyltransferase 4 (PRMT4) is a transcription regulator involved in the modulation of oxidative stress and autophagy, but its role in DOX-induced cardiomyopathy (DIC) and ferroptosis remains elusive. Herein, we aimed to investigate the involvement and the underlying mechanisms of PRMT4 in the pathogenesis of DIC. Our present study revealed that the expression level of PRMT4 was markedly decreased in DOX-treated cardiomyocytes. Interestingly, it is noted that PRMT4 overexpression accelerated ferroptosis to aggravate DIC, while its gene disruption or pharmaceutical inhibition exhibited the opposite effect. Mechanistically, our observation demonstrated that PRMT4 interacted with the nuclear factor erythroid 2-related factor 2 (Nrf2) to promote its enzymatic methylation, which restricted the nuclear translocation of Nrf2 and subsequently suppressed the transcription of glutathione peroxidase 4 (GPX4). Importantly, the detrimental role of PRMT4 in DOX-induced cardiomyocyte ferroptosis was abolished by Nrf2 activation or Fer-1 administration. Collectively, our data reveal that PRMT4 inhibits Nrf2/GPX4 signaling to accelerate ferroptosis in DIC, suggesting that targeting PRMT4 may present as a potential preventive strategy against the development of DIC.

Cardio-Oncology: Mechanisms, Drug Combinations, and Reverse Cardio-Oncology

Chemotherapy, radiotherapy, targeted therapy, and immunotherapy have brought hope to cancer patients. With the prolongation of survival of cancer patients and increased clinical experience, cancer-therapy-induced cardiovascular toxicity has attracted attention. The adverse effects of cancer therapy that can lead to life-threatening or induce long-term morbidity require rational approaches to prevention and treatment, which requires deeper understanding of the molecular biology underpinning the disease. In addition to the drugs used widely for cardio-protection, traditional Chinese medicine (TCM) formulations are also efficacious and can be expected to achieve “personalized treatment” from multiple perspectives. Moreover, the increased prevalence of cancer in patients with cardiovascular disease has spurred the development of “reverse cardio-oncology”, which underscores the urgency of collaboration between cardiologists and oncologists. This review summarizes the mechanisms by which cancer therapy induces cardiovascular toxicity, the combination of antineoplastic and cardioprotective drugs, and recent advances in reverse cardio-oncology.

Dapagliflozin Mitigates Doxorubicin-Caused Myocardium Damage by Regulating AKT-Mediated Oxidative Stress, Cardiac Remodeling, and Inflammation

Doxorubicin (Dox) is a commonly used anthracycline chemotherapy with a side effect of cardiotoxicity, which may increase the risk of heart failure for cancer patients. Although various studies have demonstrated the cardioprotective property of dapagliflozin (DAPA), a sodium-glucose cotransporter 2 inhibitor, the detailed mechanism underlying its effect on Dox-induced cardiomyopathy is still limited. In this study, we showed that DAPA induced the activation of AKT/PI3K signaling in cardiac myoblast H9c2 cells following Dox treatment, leading to the upregulation of antioxidant HO-1, NQO1, and SOD, as well as an improved mitochondrial dysfunction via Nrf2. In addition, the reduced oxidative stress resulted in the downregulation of hypertrophy (ANP and BNP) and fibrosis (phospho-Smad3, collagen I, fibronectin, and α-SMA) markers. Furthermore, the inflammatory IL-8 concentration was inhibited after DAPA, possibly through PI3K/AKT/Nrf2/p38/NF-κB signaling. Moreover, our results were validated in vivo, and echocardiography results suggested an improved cardiac function in DAPA-receiving rats. In summary, we demonstrated that the administration of DAPA could mitigate the Dox-elicited cardiotoxicity by reducing oxidative stress, mitochondrial dysfunction, fibrosis, hypertrophy, and inflammation via PI3K/AKT/Nrf2 signaling.

Mulberrin Confers Protection against Doxorubicin-Induced Cardiotoxicity via Regulating AKT Signaling Pathways in Mice

Doxorubicin (DOX) is an antitumor anthracycline, but its clinical use was largely limited by its cardiac toxicity. DOX-induced oxidative damage and cardiomyocyte loss have been recognized as the potential causative mechanisms of this cardiac toxicity. Growing interests are raised on mulberrin (Mul) for its wide spectrum of biological activities, including antioxidative and anti-inflammatory properties. The aim of this study was to investigate the effect of Mul on DOX-induced heart injury and to clarify the underlying mechanism. Mice were given daily 60 mg/kg of Mul via gavage for 10 days. Mice received an intraperitoneal injection of DOX to mimic the model of DOX-related acute cardiac injury at the seventh day of Mul treatment. Mul-treated mice had an attenuated cardiac injured response and improved cardiac function after DOX injection. DOX-induced oxidative damage, inflammation accumulation, and myocardial apoptosis were largely attenuated by the treatment of Mul. Activated protein kinase B (AKT) activation was essential for the protective effects of Mul against DOX-induced cardiac toxicity, and AKT inactivation abolished Mul-mediated protective effects against DOX cardiotoxicity. In conclusion, Mul treatment attenuated DOX-induced cardiac toxicity via activation of the AKT signaling pathway. Mul might be a promising therapeutic agent against DOX-induced cardiac toxicity.

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.

Protective Effects of Amauroderma rugosum on Doxorubicin-Induced Cardiotoxicity through Suppressing Oxidative Stress, Mitochondrial Dysfunction, Apoptosis, and Activating Akt/mTOR and Nrf2/HO-1 Signaling Pathways

Clinical outcomes for doxorubicin (Dox) are limited by its cardiotoxicity but a combination of Dox and agents with cardioprotective activities is an effective strategy to improve its therapeutic outcome. Natural products provide abundant resources to search for novel cardioprotective agents. Ganoderma lucidum (GL) is the most well-known edible mushroom within the Ganodermataceae family. It is commonly used in traditional Chinese medicine or as a healthcare product. Amauroderma rugosum (AR) is another genus of mushroom from the Ganodermataceae family, but its pharmacological activity and medicinal value have rarely been reported. In the present study, the cardioprotective effects of the AR water extract against Dox-induced cardiotoxicity were studied in vitro and in vivo. Results showed that both the AR and GL extracts could potentiate the anticancer effect of Dox. The AR extract significantly decreased the oxidative stress, mitochondrial dysfunction, and apoptosis seen in Dox-treated H9c2 rat cardiomyocytes. However, knockdown of Nrf2 by siRNA abolished the protective effects of AR in these cells. In addition, Dox upregulated the expression of proapoptotic proteins and downregulated the Akt/mTOR and Nrf2/HO-1 signaling pathways, and these effects could be reversed by the AR extract. Consistently, the AR extract significantly prolonged survival time, reversed weight loss, and reduced cardiac dysfunction in Dox-treated mice. In addition, oxidative stress and apoptosis were suppressed, while Nrf2 and HO-1 expressions were elevated in the heart tissues of Dox-treated mice after treatment with the AR extract. However, the GL extract had less cardioprotective effect against Dox in both the cell and animal models. In conclusion, the AR water extract demonstrated a remarkable cardioprotective effect against Dox-induced cardiotoxicity. One of the possible mechanisms for this effect was the upregulation of the mTOR/Akt and Nrf2/HO-1-dependent pathways, which may reduce oxidative stress, mitochondrial dysfunction, and cardiomyocyte apoptosis. These findings suggested that AR may be beneficial for the heart, especially in patients receiving Dox-based chemotherapy.

Costus speciosus extract protects against the oxidative damage of zearalenone via modulation of inflammatory cytokines, Nrf2 and iNOS gene expression in rats

Zearalenone (ZEN) is a non-steroidal estrogenic mycotoxin that induces severe health disturbances in humans and animals. This study aimed to determine the bioactive compounds in Costus speciosus extract (CSE) using GC-MS and evaluate its protective capability against ZEN-induced oxidative damage, genotoxicity, and cytotoxicity in rats. Six groups of male Sprague Dawley rats were treated orally for 15 days including the control group, CSE-treated groups at low (200 mg/kg b. w) or high (400 mg/kg b. w) dose, ZEN-treated group (40 μg/kg b. w), and the groups treated with ZEN plus the low or the high dose of CSE. Blood and tissue samples were collected for different assays and pathological analyses. The results of GC-MS indicated the identification of 6 compounds and Azulene was the major. Animals that received ZEN showed severe disturbances in serum biochemical, cytokines, oxidative stress indicators, mRNA expression of iNOS, Nrf2, and inflammatory-related genes. ZEN also increased micronucleated polychromatic erythrocytes (MNPCEs) and comet tail formation in bone marrow cells along with the disturbances in the histological architecture of the liver and kidney. Co-administration of CSE plus ZEN could normalize the majority of the tested parameters and the histological picture at a dose as low as 200 mg/kg b. w. Therefore, CSE protects against ZEN toxicity via its antioxidant activity, modulation of iNOS, inflammatory-related genes, and the Nrf2 pathway and it could be used in the endemic regions.

Dimethyl Fumarate Ameliorates Doxorubicin-Induced Cardiotoxicity By Activating the Nrf2 Pathway

Doxorubicin (DOX) is limited in clinical application because of its cardiotoxicity. Oxidative stress and apoptosis are crucial in DOX-induced cardiac injury. Dimethyl fumarate (DMF) is an FDA-approved oral drug with powerful effects to reduce oxidative stress and apoptosis through the Nrf2 pathway. This study was aimed to determine whether DMF can protect against DOX-induced cardiac injury. We used both neonatal rat cardiomyocytes (NRCMs) in vitro and DOX-induced cardiac toxicity in vivo to explore the effects of DMF. The results showed that DMF significantly improved cell viability and morphology in NRCMs. In addition, DMF alleviated DOX-induced cardiac injury in rats, as evidenced by decreased CK-MB, LDH levels, improved survival rates, cardiac function, and pathological changes. Moreover, DMF significantly inhibited cardiac oxidative stress by reducing MDA levels and increasing GSH, SOD, and GSH-px levels. And DMF also inhibited DOX-induced cardiac apoptosis by modulating Bax, Bcl-2 and cleaved caspase-3 expression. Moreover, DMF exerted its protective effects against DOX by promoting Nrf2 nuclear translocation, which activated its downstream antioxidant gene Hmox1. Silencing of Nrf2 attenuated the protective effects of DMF in NRCMs as manifested by increased intracellular oxidative stress, elevated apoptosis levels, and decreased cell viability. In addition, DMF showed no protective effects on the viability of DOX-treated tumor cells, which suggested that DMF does not interfere with the antitumor effect of DOX in vitro. In conclusion, our data confirmed that DMF alleviated DOX-induced cardiotoxicity by regulating oxidative stress and apoptosis through the Nrf2 pathway. DMF may serve as a new candidate to alleviate DOX-related cardiotoxicity in the future.

Promoting mitochondrial fusion in doxorubicin-induced cardiotoxicity: a novel therapeutic target for cardioprotection

Changes in mitochondrial dynamics have been recognized as being one of the mechanisms related to cardiotoxicity following a high cumulative dose of doxorubicin (DOX).  A mitochondrial division inhibitor (Mdivi-1) and fusion promoter (M1) have been shown to be cardioprotective in a variety of cardiovascular settings, however their anti-cardiotoxic efficacy against DOX therapy remains unclear.  We therefore investigated whether treatment with Mdivi-1 and M1 protect the heart against DOX-induced cardiotoxicity via mitochondria-targeted pathways.  Male Wistar rats (n=40) received DOX (3 mg/kg, 6 doses, n=32) or 3% DMSO in the normal saline solution (NSS) (n=8) as a control.  DOX-injected rats were given one of four treatments beginning with the first DOX injection via intraperitoneal injection: 1) 3% DMSO in NSS (n=8), 2) Mdivi-1 (1.2 mg/kg/day, n=8), 3) M1 (2 mg/kg/day, n=8), and 4) Mdivi-1+M1 (n=8) for 30 days.  Cardiac function, mitochondrial function, oxidative stress, myocardial injury, and protein expression associated with inflammation, autophagy, mitophagy, apoptosis and mitochondrial dynamics were determined.  DOX caused a significant deterioration in mitochondrial function and dynamic regulation, and an increase in markers of oxidative stress, inflammation, myocardial injury, apoptosis, autophagy, and mitophagy, resulting in impaired cardiac function.  Co-treatment of DOX with Mdivi-1, M1, or a combination of the two mitigated these detrimental effects of DOX.  These findings imply that either inhibiting fission or promoting fusion of mitochondria protects the heart from DOX-induced myocardial damage.  Modulation of mitochondrial dynamics could be a novel therapeutic target in alleviating DOX-induced cytotoxic effects without compromising its anti-cancer efficacy.

Setanaxib (GKT137831) Ameliorates Doxorubicin-Induced Cardiotoxicity by Inhibiting the NOX1/NOX4/Reactive Oxygen Species/MAPK Pathway

Background: Doxorubicin (DOX)-induced cardiotoxicity is a highly concerning issue, and the mechanism by which DOX induces cardiotoxicity is likely to be multifactorial. NADPH oxidase (NOX) is associated with DOX-induced cardiotoxicity. Setanaxib (GKT137831), a preferential direct inhibitor of NOX1 and NOX4, can delay or prevent the progression of many cardiovascular disorders by inhibiting reactive oxygen species (ROS) generation. In this study, we investigated the role of GKT137831 in ameliorating DOX-induced cardiotoxicity and the potential mechanisms of its action.

Methods and Results: The mice model of cardiotoxicity induced by DOX was established, and GKT137831 treatment was performed at the same time. Neonatal rat cardiomyocytes (NRCMs) were treated with DOX or GKT137831 for in vitro experiments. We found that DOX administration impaired cardiac function in vivo, reflected by decreased left ventricular ejection fraction (LVEF) and fractional shortening (FS%). DOX also impaired the viability of NRCMs in vitro. In addition, DOX increased the levels of NOX1 and NOX4 expression and ROS production and the cardiomyocyte apoptosis rate, both in vivo and in vitro. GKT137831 improved cardiac function, as indicated by the increased LVEF and FS%. In vitro, GKT137831 improved NRCM viability. It also decreased ROS production and the cardiomyocyte apoptosis rate. Apoptotic indices, such as cleaved PARP (c-PARP), cleaved caspase 3 (CC3) and BAX expression levels, were decreased, and the antiapoptotic index of Bcl-2 expression was increased. DOX markedly activated phosphorylated JNK, ERK and p38 proteins in NRCMs. Specific inhibitors of JNK (SP600125), ERK (PD98059) or p38 (SB203580) inhibited DOX-induced apoptosis of NRCMs. GKT137831 pretreatment inhibited excessive DOX-induced MAPK pathway activation.

Conclusion: This study revealed that GKT137831 can alleviate DOX-induced cardiomyocyte apoptosis by inhibiting NOX1/4-driven ROS production. The upregulation of MAPK pathway induced by NOX1/4-derived ROS production may be the potential mechanism of GKT137831 action. GKT137831 may be a potential drug candidate to ameliorate DOX-induced cardiotoxicity.