Chronic doxorubicin cardiotoxicity is mediated by oxidative DNA damage-ATM-p53-apoptosis pathway and attenuated by pitavastatin through the inhibition of Rac1 activity

Semaglutide attenuates doxorubicin-induced cardiotoxicity by ameliorating BNIP3-Mediated mitochondrial dysfunction

AIMS

Doxorubicin is a powerful chemotherapeutic agent for cancer, whose use is limited due to its potential cardiotoxicity. Semaglutide (SEMA), a novel analog of glucagon-like peptide-1 (GLP-1), has received widespread attention for the treatment of diabetes. However, increasing evidence has highlighted its potential therapeutic benefits on cardiac function. Therefore, the objective of this study was to examine the efficacy of semaglutide in ameliorating doxorubicin-induced cardiotoxicity.

METHODS AND RESULTS

Doxorubicin-induced cardiotoxicity is an established model to study cardiac function. Cardiac function was studied by transthoracic echocardiography and invasive hemodynamic monitoring. The results showed that semaglutide significantly ameliorated doxorubicin-induced cardiac dysfunction. RNA sequencing suggested that Bnip3 is the candidate gene that impaired the protective effect of semaglutide in doxorubicin-induced cardiotoxicity. To determine the role of BNIP3 on the effect of semaglutide in doxorubicin-induced cardiotoxicity, BNIP3 with adeno-associated virus serotype 9 (AAV9) expressing cardiac troponin T (cTnT) promoter was injected into tail vein of C57/BL6J mice to overexpress BNIP3, specifically in the heart. Overexpression of BNIP3 prevented the improvement in cardiac function caused by semaglutide. In vitro experiments showed that semaglutide, via PI3K/AKT pathway, reduced BNIP3 expression in the mitochondria, improving mitochondrial function.

CONCLUSION

Semaglutide ameliorates doxorubicin-induced mitochondrial and cardiac dysfunction via PI3K/AKT pathway, by reducing BNIP3 expression in mitochondria. The improvement in mitochondrial function reduces doxorubicin-mediated cardiac injury and improves cardiac function. Therefore, semaglutide is a potential therapy to reduce doxorubicin-induced acute cardiotoxicity.

Cardiomyocytes, cardiac endothelial cells and fibroblasts contribute to anthracycline-induced cardiac injury through RAS-homologous small GTPases RAC1 and CDC42

The clinical use of the DNA damaging anticancer drug doxorubicin (DOX) is limited by irreversible cardiotoxicity, which depends on the cumulative dose. The RAS-homologous (RHO) small GTPase RAC1 contributes to DOX-induced DNA damage formation and cardiotoxicity. However, the pathophysiological relevance of other RHO GTPases than RAC1 and different cardiac cell types (i.e., cardiomyocytes, non-cardiomyocytes) for DOX-triggered cardiac damage is unclear. Employing diverse in vitro and in vivo models, we comparatively investigated the level of DOX-induced DNA damage in cardiomyocytes versus non-cardiomyocytes (endothelial cells and fibroblasts), in the presence or absence of selected RHO GTPase inhibitors. Non-cardiomyocytes exhibited the highest number of DOX-induced DNA double-strand breaks (DSB), which were efficiently repaired in vitro. By contrast, rather low levels of DSB were formed in cardiomyocytes, which however remained largely unrepaired. Moreover, DOX-induced apoptosis was detected only in non-cardiomyocytes but not in cardiomyocytes. Pharmacological inhibitors of RAC1 and CDC42 most efficiently attenuated DOX-induced DNA damage in all cell types examined in vitro. Consistently, immunohistochemical analyses revealed that the RAC1 inhibitor NSC23766 and the pan-RHO GTPase inhibitor lovastatin reduced the level of DOX-induced residual DNA damage in both cardiomyocytes and non-cardiomyocytes in vivo. Overall, we conclude that endothelial cells, fibroblasts and cardiomyocytes contribute to the pathophysiology of DOX-induced cardiotoxicity, with RAC1- and CDC42-regulated signaling pathways being especially relevant for DOX-stimulated DSB formation and DNA damage response (DDR) activation. Hence, we suggest dual targeting of RAC1/CDC42-dependent mechanisms in multiple cardiac cell types to mitigate DNA damage-dependent cardiac injury evoked by DOX-based anticancer therapy.

Cardiac miRNA expression during the development of chronic anthracycline-induced cardiomyopathy using an experimental rabbit model

Background: Anthracycline cardiotoxicity is a well-known complication of cancer treatment, and miRNAs have emerged as a key driver in the pathogenesis of cardiovascular diseases. This study aimed to investigate the expression of miRNAs in the myocardium in early and late stages of chronic anthracycline induced cardiotoxicity to determine whether this expression is associated with the severity of cardiac damage. Method: Cardiotoxicity was induced in rabbits via daunorubicin administration (daunorubicin, 3 mg/kg/week; for five and 10 weeks), while the control group received saline solution. Myocardial miRNA expression was first screened using TaqMan Advanced miRNA microfluidic card assays, after which 32 miRNAs were selected for targeted analysis using qRT-PCR. Results: The first subclinical signs of cardiotoxicity (significant increase in plasma cardiac troponin T) were observed after 5 weeks of daunorubicin treatment. At this time point, 10 miRNAs (including members of the miRNA-34 and 21 families) showed significant upregulation relative to the control group, with the most intense change observed for miRNA-1298-5p (29-fold change, p < 0.01). After 10 weeks of daunorubicin treatment, when a further rise in cTnT was accompanied by significant left ventricle systolic dysfunction, only miR-504-5p was significantly (p < 0.01) downregulated, whereas 10 miRNAs were significantly upregulated relative to the control group; at this time-point, the most intense change was observed for miR-34a-5p (76-fold change). Strong correlations were found between the expression of multiple miRNAs (including miR-34 and mir-21 family and miR-1298-5p) and quantitative indices of toxic damage in both the early and late phases of cardiotoxicity development. Furthermore, plasma levels of miR-34a-5p were strongly correlated with the myocardial expression of this miRNA. Conclusion: To the best of our knowledge, this is the first study that describes alterations in miRNA expression in the myocardium during the transition from subclinical, ANT-induced cardiotoxicity to an overt cardiotoxic phenotype; we also revealed how these changes in miRNA expression are strongly correlated with quantitative markers of cardiotoxicity.

TBC1D15 deficiency protects against doxorubicin cardiotoxicity via inhibiting DNA-PKcs cytosolic retention and DNA damage

Clinical application of doxorubicin (DOX) is heavily hindered by DOX cardiotoxicity. Several theories were postulated for DOX cardiotoxicity including DNA damage and DNA damage response (DDR), although the mechanism(s) involved remains to be elucidated. This study evaluated the potential role of TBC domain family member 15 (TBC1D15) in DOX cardiotoxicity. Tamoxifen-induced cardiac-specific Tbc1d15 knockout (Tbc1d15CKO) or Tbc1d15 knockin (Tbc1d15CKI) male mice were challenged with a single dose of DOX prior to cardiac assessment 1 week or 4 weeks following DOX challenge. Adenoviruses encoding TBC1D15 or containing shRNA targeting Tbc1d15 were used for Tbc1d15 overexpression or knockdown in isolated primary mouse cardiomyocytes. Our results revealed that DOX evoked upregulation of TBC1D15 with compromised myocardial function and overt mortality, the effects of which were ameliorated and accentuated by Tbc1d15 deletion and Tbc1d15 overexpression, respectively. DOX overtly evoked apoptotic cell death, the effect of which was alleviated and exacerbated by Tbc1d15 knockout and overexpression, respectively. Meanwhile, DOX provoked mitochondrial membrane potential collapse, oxidative stress and DNA damage, the effects of which were mitigated and exacerbated by Tbc1d15 knockdown and overexpression, respectively. Further scrutiny revealed that TBC1D15 fostered cytosolic accumulation of the cardinal DDR element DNA-dependent protein kinase catalytic subunit (DNA-PKcs). Liquid chromatography-tandem mass spectrometry and co-immunoprecipitation denoted an interaction between TBC1D15 and DNA-PKcs at the segment 594-624 of TBC1D15. Moreover, overexpression of TBC1D15 mutant (∆594-624, deletion of segment 594-624) failed to elicit accentuation of DOX-induced cytosolic retention of DNA-PKcs, DNA damage and cardiomyocyte apoptosis by TBC1D15 wild type. However, Tbc1d15 deletion ameliorated DOX-induced cardiomyocyte contractile anomalies, apoptosis, mitochondrial anomalies, DNA damage and cytosolic DNA-PKcs accumulation, which were canceled off by DNA-PKcs inhibition or ATM activation. Taken together, our findings denoted a pivotal role for TBC1D15 in DOX-induced DNA damage, mitochondrial injury, and apoptosis possibly through binding with DNA-PKcs and thus gate-keeping its cytosolic retention, a route to accentuation of cardiac contractile dysfunction in DOX-induced cardiotoxicity.

Systematic analysis of the material basis and mechanism of total saponins of mountain cultivated ginseng against doxorubicin-induced cardiotoxicity based on integrating network pharmacology and in vivo substance profiling

INTRODUCTION

Doxorubicin-induced cardiotoxicity (DIC) is a serious obstacle to oncologic treatment. Mountain cultivated ginseng (MCG) exhibits stronger pharmacological effects than cultivated ginseng (CG) mainly due to the differences in ginsenosides. However, the material basis and the underlying mechanism of the protective effects of total saponins of MCG (TSMCG) against DIC are unclear.

OBJECTIVES

We aimed to elucidate the material basis and the pharmacodynamic effects of TSMCG on DIC as well as the underlying mechanisms.

METHODS

To comprehensively analyze the effective substances, the chemical components of TSMCG and their prototypes or metabolites in vivo were characterized through UHPLC/Q-TOF-MS. Then, an absorbed component-target-disease network was established to explore the mechanisms underlying the protective effects of TSMCG against DIC. H9c2 cells were employed for pharmacodynamic assays. The mechanism was verified by Western blot and molecular docking simulations.

RESULTS

A total of 56 main ginsenosides were identified in TSMCG, including 27 ginsenosides of PPD type, 15 ginsenosides of PPT type, two ginsenosides of OA types, and 12 ginsenosides of other types. Moreover, 55 ginsenoside prototypes or metabolites in vivo were tentatively characterized. Ginsenoside Ra1 , a differential compound between MCG and CG, could be metabolized by oxidation and deglycosylation. Network pharmacology showed that AKT1, p53, and STAT3 are core targets of 62 intersecting genes. Molecular docking results indicated that most of the ginsenosides have favorable affinity with these core targets. After doxorubicin exposure, TSMCG could increase cell viability and inhibit apoptosis in a dose-dependent manner.

CONCLUSION

Our work reveals a novel comprehensive strategy to study the material basis of the protective effects of TSMCG against DIC and the underlying mechanisms through integrating in vivo substance identification, metabolic profiling, network pharmacology, pharmacodynamic evaluation, and mechanism verification.

Moringa oleifera Leaves Extract Ameliorates Doxorubicin-Induced Cardiotoxicity via Its Mitochondrial Biogenesis Modulatory Activity in Rats

Background

Doxorubicin, an anthracycline class of anticancer, is an effective chemotherapeutic agent with serious adverse effects, mainly cardiotoxicity. Several possible causes of doxorubicin cardiotoxicity are increased oxidative stress, nucleic acid and protein synthesis inhibition, cardiomyocyte apoptosis, and mitochondrial biogenesis disruptions. Moringa oleifera (MO), a naturally derived medicine, is known for its antioxidative properties and activity in alleviating mitochondrial dysfunction. To determine the potency and possible cardioprotective mechanism of MO leaves aqueous extract via the mitochondrial biogenesis pathway in doxorubicin-induced rats.

Methods

Twenty-four Sprague-Dawley rats were divided into four groups of six. The first group was normal rats; the second group was treated with doxorubicin 4 mg/kg BW intraperitoneally once weekly for four weeks; the third and fourth groups were treated with doxorubicin 4 mg/kg BW intraperitoneally once weekly, and MO leaves extract at 200 mg/kg BW or 400 mg/kg BW orally daily, for four weeks. At the end of the fourth week, blood and cardiac tissues were obtained and analyzed for cardiac biomarkers, mitochondrial DNA copy number, mRNA expressions of peroxisome-activated receptor-gamma coactivator-1 alpha (PGC-1α), the nuclear factor erythroid 2-related factor 2 (Nrf2), superoxide dismutase 2 (SOD2), caspase 3, the activity of glutathione peroxidase (GPx), levels of 8-hydroxy-2-deoxyguanosine (8-OH-dG), and malondialdehyde.

Results

MO leaves extract was shown to decrease biomarkers of cardiac damage (LDH and CK-MB), malondialdehyde levels, and GPx activity. These changes align with the reduction of mRNA expressions of caspase-3, the increase of mRNA expressions of PGC-1α and Nrf2, and the elevation of mitochondrial DNA copy number. MO leaves extracts did not influence the mRNA expressions of superoxide dismutase 2 (SOD2) or the levels of 8-OH-dG.

Conclusion

Moringa oleifera leaves extract ameliorates doxorubicin-induced cardiotoxicity by reducing apoptosis and restoring gene expression of PGC-1α and Nrf2, a key regulator in mitochondrial biogenesis.

Vernonia amygdalina Ethanol Extract Protects against Doxorubicin-Induced Cardiotoxicity via TGFβ, Cytochrome c, and Apoptosis

Doxorubicin (DOX) has been extensively utilized in cancer treatment. However, DOX administration has adverse effects, such as cardiac injury. This study intends to analyze the expression of TGF, cytochrome c, and apoptosis on the cardiac histology of rats induced with doxorubicin, since the prevalence of cardiotoxicity remains an unpreventable problem due to a lack of understanding of the mechanism underlying the cardiotoxicity result. Vernonia amygdalina ethanol extract (VAEE) was produced by soaking dried Vernonia amygdalina leaves in ethanol. Rats were randomly divided into seven groups: K- (only given doxorubicin 15 mg/kgbw), KN (water saline), P100, P200, P400, P4600, and P800 (DOX 15 mg/kgbw + 100, 200, 400, 600, and 800 mg/kgbw extract); at the end of the study, rats were scarified, and blood was taken directly from the heart; the heart was then removed. TGF, cytochrome c, and apoptosis were stained using immunohistochemistry, whereas SOD, MDA, and GR concentration were evaluated using an ELISA kit. In conclusion, ethanol extract might protect the cardiotoxicity produced by doxorubicin by significantly reducing the expression of TGF, cytochrome c, and apoptosis in P600 and P800 compared to untreated control K- (p < 0.001). These findings suggest that Vernonia amygdalina may protect cardiac rats by reducing the apoptosis, TGF, and cytochrome c expression while not producing the doxorubicinol as doxorubicin metabolite. In the future, Vernonia amygdalina could be used as herbal preventive therapy for patient administered doxorubicin to reduce the incidence of cardiotoxicity.

p53 at the Crossroads between Doxorubicin-Induced Cardiotoxicity and Resistance: A Nutritional Balancing Act

Doxorubicin (DOX) is a highly effective chemotherapeutic drug, but its long-term use can cause cardiotoxicity and drug resistance. Accumulating evidence demonstrates that p53 is directly involved in DOX toxicity and resistance. One of the primary causes for DOX resistance is the mutation or inactivation of p53. Moreover, because the non-specific activation of p53 caused by DOX can kill non-cancerous cells, p53 is a popular target for reducing toxicity. However, the reduction in DOX-induced cardiotoxicity (DIC) via p53 suppression is often at odds with the antitumor advantages of p53 reactivation. Therefore, in order to increase the effectiveness of DOX, there is an urgent need to explore p53-targeted anticancer strategies owing to the complex regulatory network and polymorphisms of the p53 gene. In this review, we summarize the role and potential mechanisms of p53 in DIC and resistance. Furthermore, we focus on the advances and challenges in applying dietary nutrients, natural products, and other pharmacological strategies to overcome DOX-induced chemoresistance and cardiotoxicity. Lastly, we present potential therapeutic strategies to address key issues in order to provide new ideas for increasing the clinical use of DOX and improving its anticancer benefits.

The Imbalance of p53-Park7 Signaling Axis Induces Iron Homeostasis Dysfunction in Doxorubicin-Challenged Cardiomyocytes

Doxorubicin (DOX)-induced cardiotoxicity (DoIC) is a major side effect for cancer patients. Recently, ferroptosis, triggered by iron overload, is demonstrated to play a role in DoIC. How iron homeostasis is dysregulated in DoIC remains to be elucidated. Here, the authors demonstrate that DOX challenge exhibits reduced contractile function and induction of ferroptosis-related phenotype in cardiomyocytes, evidenced by iron overload, lipid peroxide accumulation, and mitochondrial dysfunction. Compared to Ferric ammonium citrate (FAC) induced secondary iron overload, DOX-challenged cardiomyocytes show a dysfunction of iron homeostasis, with decreased cytoplasmic and mitochondrial iron-sulfur (FeS) cluster-mediated aconitase activity and abnormal expression of iron homeostasis-related proteins. Mechanistically, mass spectrometry analysis identified DOX-treatment induces p53-dependent degradation of Parkinsonism associated deglycase (Park7) which results in iron homeostasis dysregulation. Park7 counteracts iron overload by regulating iron regulatory protein family transcription while blocking mitochondrial iron uptake. Knockout of p53 or overexpression of Park7 in cardiomyocytes remarkably restores the activity of FeS cluster and iron homeostasis, inhibits ferroptosis, and rescues cardiac function in DOX treated animals. These results demonstrate that the iron homeostasis plays a key role in DoIC ferroptosis. Targeting of the newly identified p53-Park7 signaling axis may provide a new approach to prevent DoIC.

Oxymatrine and insulin resistance: Focusing on mechanistic intricacies involve in diabetes associated cardiomyopathy via SIRT1/AMPK and TGF-β signaling pathway

Cardiomyopathy (CDM) and related morbidity and mortality are increasing at an alarming rate, in large part because of the increase in the number of diabetes mellitus cases. The clinical consequence associated with CDM is heart failure (HF) and is considerably worse for patients with diabetes mellitus, as compared to nondiabetics. Diabetic cardiomyopathy (DCM) is characterized by structural and functional malfunctioning of the heart, which includes diastolic dysfunction followed by systolic dysfunction, myocyte hypertrophy, cardiac dysfunctional remodeling, and myocardial fibrosis. Indeed, many reports in the literature indicate that various signaling pathways, such as the AMP-activated protein kinase (AMPK), silent information regulator 1 (SIRT1), PI3K/Akt, and TGF-β/smad pathways, are involved in diabetes-related cardiomyopathy, which increases the risk of functional and structural abnormalities of the heart. Therefore, targeting these pathways augments the prevention as well as treatment of patients with DCM. Alternative pharmacotherapy, such as that using natural compounds, has been shown to have promising therapeutic effects. Thus, this article reviews the potential role of the quinazoline alkaloid, oxymatrine obtained from the Sophora flavescensin CDM associated with diabetes mellitus. Numerous studies have given a therapeutic glimpse of the role of oxymatrine in the multiple secondary complications related to diabetes, such as retinopathy, nephropathy, stroke, and cardiovascular complications via reductions in oxidative stress, inflammation, and metabolic dysregulation, which might be due to targeting signaling pathways, such as AMPK, SIRT1, PI3K/Akt, and TGF-β pathways. Thus, these pathways are considered central regulators of diabetes and its secondary complications, and targeting these pathways with oxymatrine might provide a therapeutic tool for the diagnosis and treatment of diabetes-associated cardiomyopathy.

DNA damage response signaling: A common link between cancer and cardiovascular diseases

DNA damage response (DDR) signaling ensures genomic and proteomic homeostasis to maintain a healthy genome. Dysregulation either in the form of down- or upregulation in the DDR pathways correlates with various pathophysiological states, including cancer and cardiovascular diseases (CVDs). Impaired DDR is studied as a signature mechanism for cancer; however, it also plays a role in ischemia-reperfusion injury (IRI), inflammation, cardiovascular function, and aging, demonstrating a complex and intriguing relationship between cancer and pathophysiology of CVDs. Accordingly, there are increasing number of reports indicating higher incidences of CVDs in cancer patients. In the present review, we thoroughly discuss (1) different DDR pathways, (2) the functional cross talk among different DDR mechanisms, (3) the role of DDR in cancer, (4) the commonalities and differences of DDR between cancer and CVDs, (5) the role of DDR in pathophysiology of CVDs, (6) interventional strategies for targeting genomic instability in CVDs, and (7) future perspective.

SIRT1 in the cardiomyocyte counteracts doxorubicin-induced cardiotoxicity via regulating histone H2AX

AIMS

Cardiotoxicity by doxorubicin predicts worse prognosis of patients. Accumulation of damaged DNA has been implicated in doxorubicin-induced cardiotoxicity. SIRT1, an NAD+-dependent histone/protein deacetylase, protects cells by deacetylating target proteins. We investigated whether SIRT1 counteracts doxorubicin-induced cardiotoxicity by mediating Ser139 phosphorylation of histone H2AX, a critical signal of the DNA damage response.

METHODS AND RESULTS

Doxorubicin (5 mg/kg per week, x4) was administered to mice with intact SIRT1 (Sirt1f/f) and mice that lack SIRT1 activity in cardiomyocytes (Sirt1f/f;MHCcre/+). Reductions in left ventricular fractional shortening and ejection fraction by doxorubicin treatment were more severe in Sirt1f/f;MHCcre/+ than in Sirt1f/f. Myocardial expression level of type-B natriuretic peptide was 2.5-fold higher in Sirt1f/f;MHCcre/+ than in Sirt1f/f after doxorubicin treatment. Sirt1f/f;MHCcre/+ showed larger fibrotic areas and higher nitrotyrosine levels in the heart after doxorubicin treatment. Although doxorubicin-induced DNA damage evaluated by TUNEL staining was enhanced in Sirt1f/f;MHCcre/+, the myocardium from Sirt1f/f;MHCcre/+ showed blunted Ser139 phosphorylation of H2AX by doxorubicin treatment. In H9c2 cardiomyocytes, SIRT1 knockdown attenuated Ser139 phosphorylation of H2AX, increased DNA damage, and enhanced caspase-3 activation under doxorubicin treatment. Immunostaining revealed that acetylation level of H2AX at Lys5 was higher in hearts from Sirt1f/f;MHCcre/+. In H9c2 cells, acetyl-Lys5-H2AX level was increased by SIRT1 knockdown and reduced by SIRT1 overexpression. Ser139 phosphorylation in response to doxorubicin treatment was blunted in a mutant H2AX with substitution of Lys5 to Gln (K5Q) that mimics acetylated lysine compared with that in wild-type H2AX. Expression of K5Q-H2AX as well as S139A-H2AX, which cannot be phosphorylated at Ser139, augmented doxorubicin-induced caspase-3 activation. Treatment of mice with resveratrol, a SIRT1 activator, attenuated doxorubicin-induced cardiac dysfunction, which was associated with a reduction in acetyl-Lys5-H2AX level and a preserved phospho-Ser139-H2AX level.

CONCLUSION

These findings suggest that SIRT1 counteracts doxorubicin-induced cardiotoxicity by mediating H2AX phosphorylation through its deacetylation in cardiomyocytes.

Proteomic, biochemical, histopathological, and elevated plus maze analysis reveals the gut damaging role of ketoprofen with Yersinia enterocolitica and altered behavior in Wistar rats

The long-term use of non-steroidal anti-inflammatory drugs (NSAIDs) is known to damage the intestinal epithelial cells (IECs) that play numerous important roles, including nutrient absorption and barrier protection. In the current study, we determined the effect of ketoprofen on the rat gut when administered with Yersinia enterocolitica. On performing the label-free quantitation of the rat gut proteins, the expression of 494 proteins out of 1628 proteins was altered, which has a profound effect on NF-kB signaling pathway, immune system, dysbiosis, and gut injury. Further, the biochemical [enhanced malondialdehyde (MDA) & hepatic enzyme activities and reduced serotonin & antioxidants levels i.e., catalase (CAT) and superoxide dismutase (SOD)] and histopathological analysis suggested the significant damage in treated rats, compared to control rats. Lastly, the elevated plus maze (EPM) study confirmed high levels of anxiety in treated rats in comparison to the control group. Altogether, results suggest that the co-administration of ketoprofen with Y. enterocolitica damages gut, alters hepatic enzyme activities, and affects behavioral responses in the treated rats.

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.

Early Doxorubicin Myocardial Injury: Inflammatory, Oxidative Stress, and Apoptotic Role of Galectin-3

Doxorubicin (DOXO) is an effective drug that is used in the treatment of a large number of cancers. Regardless of its important chemotherapeutic characteristics, its usage is restricted because of its serious side effects; the most obvious is cardiotoxicity, which can manifest acutely or years after completion of treatment, leading to left ventricular dysfunction, dilated cardiomyopathy, and heart failure. Galectin 3 (Gal-3) is a beta galactoside binding lectin that has different roles in normal and pathophysiological conditions. Gal-3 was found to be upregulated in animal models, correlating with heart failure, atherosclerosis, and myocardial infarction. Male C57B6/J and B6.Cg-Lgals3 <tm 1 Poi>/J Gal-3 knockout (KO) mice were used for a mouse model of acute DOXO-induced cardiotoxicity. Mice were given DOXO or vehicle (normal saline), after which the mice again had free access to food and water. Heart and plasma samples were collected 5 days after DOXO administration and were used for tissue processing, staining, electron microscopy, and enzyme-linked immunosorbent assay (ELISA). There was a significant increase in the heart concentration of Gal-3 in Gal-3 wild type DOXO-treated mice when compared with the sham control. There were significantly higher concentrations of heart cleaved caspase-3, plasma troponin I, plasma lactate dehydrogenase, and plasma creatine kinase in Gal-3 KO DOXO-treated mice than in Gal-3 wild type DOXO-treated mice. Moreover, there were significantly higher heart antioxidant proteins and lower oxidative stress in Gal-3 wild type DOXO-treated mice than in Gal-3 KO DOXO-treated mice. In conclusion, Gal-3 can affect the redox pathways and regulate cell survival and death of the myocardium following acute DOXO injury.

Statins Protect Against Early Stages of Doxorubicin-induced Cardiotoxicity Through the Regulation of Akt Signaling and SERCA2

Background

Doxorubicin-induced cardiomyopathy (DICM) is one of the complications that can limit treatment for a significant number of cancer patients. In animal models, the administration of statins can prevent the development of DICM. Therefore, the use of statins with anthracyclines potentially could enable cancer patients to complete their chemotherapy without added cardiotoxicity. The precise mechanism mediating the cardioprotection is not well understood. The purpose of this study is to determine the molecular mechanism by which rosuvastatin confers cardioprotection in a mouse model of DICM.

Methods

Rosuvastatin was intraperitoneally administered into adult male mice at 100 μg/kg daily for 7 days, followed by a single intraperitoneal doxorubicin injection at 10 mg/kg. Animals continued to receive rosuvastatin daily for an additional 14 days. Cardiac function was assessed by echocardiography. Optical calcium mapping was performed on retrograde Langendorff perfused isolated hearts. Ventricular tissue samples were analyzed by immunofluorescence microscopy, Western blotting, and quantitative polymerase chain reaction.

Results

Exposure to doxorubicin resulted in significantly reduced fractional shortening (27.4% ± 1.11% vs 40% ± 5.8% in controls; P < 0.001) and re-expression of the fetal gene program. However, we found no evidence of maladaptive cardiac hypertrophy or adverse ventricular remodeling in mice exposed to this dose of doxorubicin. In contrast, rosuvastatin-doxorubicin-treated mice maintained their cardiac function (39% ± 1.26%; P < 0.001). Mechanistically, the effect of rosuvastatin was associated with activation of Akt and phosphorylation of phospholamban with preserved sarcoplasmic/endoplasmic reticulum Ca²⁺ transporting 2 (SERCA2)-mediated Ca²⁺ reuptake. These effects occurred independently of perturbations in ryanodine receptor 2 function.

Conclusions

Rosuvastatin counteracts the cardiotoxic effects of doxorubicin by directly targeting sarcoplasmic calcium cycling.

The Role of PKC-MAPK Signalling Pathways in the Development of Hyperglycemia-Induced Cardiovascular Complications

Cardiovascular disease is the most common cause of death among diabetic patients worldwide. Hence, cardiovascular wellbeing in diabetic patients requires utmost importance in disease management. Recent studies have demonstrated that protein kinase C activation plays a vital role in the development of cardiovascular complications via its activation of mitogen-activated protein kinase (MAPK) cascades, also known as PKC-MAPK pathways. In fact, persistent hyperglycaemia in diabetic conditions contribute to preserved PKC activation mediated by excessive production of diacylglycerol (DAG) and oxidative stress. PKC-MAPK pathways are involved in several cellular responses, including enhancing oxidative stress and activating signalling pathways that lead to uncontrolled cardiac and vascular remodelling and their subsequent dysfunction. In this review, we discuss the recent discovery on the role of PKC-MAPK pathways, the mechanisms involved in the development and progression of diabetic cardiovascular complications, and their potential as therapeutic targets for cardiovascular management in diabetic patients.

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.

Statins for Cardiac and Vascular Protection During and After Cancer Therapy

PURPOSE OF REVIEW

Although cancer treatments have increased overall survival rates, the cardiovascular consequences of cancer therapy place patients at an increased risk of adverse outcomes. This manuscript presents data accumulated to date regarding cardiovascular outcomes relating to the administration of 3-hydroxy-3-methylglutarylcoenzyme-A reductase inhibitor (or statin) therapy in individuals receiving potentially cardiotoxic cancer treatments.

RECENT FINDINGS

Retrospective observational studies in humans and randomized controlled trials in animals suggest that statins may reduce cancer-specific and all-cause mortality. Further, statins may attenuate cancer therapy-induced declines in left ventricular ejection fraction (LVEF) and increases in blood pressure. Observational studies suggest a potential attenuation in LVEF decline in patients with cancer and primary or secondary indications to receive a statin for prevention of cardiovascular events. Large randomized clinical trials are warranted to understand the efficacy and potential impacts of statin class, dosage, and duration on cardiovascular outcomes in patients treated for cancer.

Harpagoside Protects Against Doxorubicin-Induced Cardiotoxicity via P53-Parkin-Mediated Mitophagy

Doxorubicin (DOX) is one of the most effective chemotherapeutic agents. However, its clinical use is limited due to the severe risk of cardiotoxicity. One of the hallmarks of doxorubicin-induced cardiotoxicity (DICT) is the cascade of mitophagy deficiency-mitochondrial oxidative injury-apoptosis, while so far, there is no preventive strategy for alleviating DICT by targeting this molecular mechanism. Excitedly, based on our previous drug screen in DICT zebrafish model, harpagoside (HAR) showed dramatic anti-DICT efficacy superior to dexrazoxane (DXZ) only cardioprotectant approved by FDA. Therefore, its pharmacological effects and molecular mechanism on DICT mouse and rat cardiomyocytes were further discussed. In vivo, HAR significantly improved cardiac function and myocardial structural lesions with concomitant of diminished mitochondrial oxidative damage and recovered mitophagy flux. In parallel, HAR protected mitophagy and mitochondria homeostasis, and repressed apoptosis in vitro. Intriguingly, both nutlin-3 (agonist of p53) and Parkin siRNA reversed these protective effects of HAR. Additional data, including fluorescence colocalization of Parkin and MitoTracker and mt-Keima for the detection of mitophagy flux and coimmunoprecipitation of p53 and Parkin, showed that HAR promoted Parkin translocation to mitochondria and substantially restored Parkin-mediated mitophagy by inhibiting the binding of p53 and Parkin. Importantly, the results of the cell viability demonstrated that cardioprotective effect of HAR did not interfere with anticancer effect of DOX on MCF-7 and HepG2 cells. Our research documented p53-Parkin-mediated cascade of mitophagy deficiency-mitochondrial dyshomeostasis-apoptosis as a pathogenic mechanism and druggable pathway and HAR as a cardioprotection on DICT by acting on novel interaction between p53 and Parkin.

CIRKIL Exacerbates Cardiac Ischemia/Reperfusion Injury by Interacting With Ku70

BACKGROUND

Ku70 participates in several pathological processes through mediating repair of DNA double-strand breaks. Our previous study has identified a highly conserved long noncoding RNA cardiac ischemia reperfusion associated Ku70 interacting lncRNA (CIRKIL) that was upregulated in myocardial infarction. The study aims to investigate whether CIRKIL regulates myocardial ischemia/reperfusion (I/R) through binding to Ku70.

METHODS

CIRKIL transgenic and knockout mice were subjected to 45-minute ischemia and 24-hour reperfusion to establish myocardial I/R model. RNA pull-down and RNA immunoprecipitation assay were used to detect the interaction between CIRKIL and Ku70.

RESULTS

The expression of CIRKIL was increased in I/R myocardium and H₂O₂-treated cardiomyocytes. Overexpression of CIRKIL increased the expression of γH₂A.X, a specific marker of DNA double-strand breaks and aggravated cardiomyocyte apoptosis, whereas knockdown of CIRKIL produced the opposite changes. Transgenic overexpression of CIRKIL aggravated cardiac dysfunction, enlarged infarct area, and worsened cardiomyocyte damage in I/R mice. Knockout of CIRKIL alleviated myocardial I/R injury. Mechanistically, CIRKIL directly bound to Ku70 to subsequently decrease nuclear translocation of Ku70 and impair DNA double-strand breaks repair. Concurrent overexpression of Ku70 mitigated CIRKIL overexpression-induced myocardial I/R injury. Furthermore, knockdown of human CIRKIL significantly suppressed cell damage induced by H₂O₂ in adult human ventricular cardiomyocytes and human induced pluripotent stem cell-derived cardiomyocytes.

CONCLUSIONS

CIRKIL is a detrimental factor in I/R injury acting via regulating nuclear translocation of Ku70 and DNA double-strand breaks repair. Thus, CIRKIL might be considered as a novel molecular target for the treatment of cardiac conditions associated with I/R injury.

OUP accepted manuscript

Cardiovascular diseases (CVDs) arise from a complex interplay among genomic, proteomic, and metabolomic abnormalities. Emerging evidence has recently consolidated the presence of robust DNA damage in a variety of cardiovascular disorders. DNA damage triggers a series of cellular responses termed DNA damage response (DDR) including detection of DNA lesions, cell cycle arrest, DNA repair, cellular senescence, and apoptosis, in all organ systems including hearts and vasculature. Although transient DDR in response to temporary DNA damage can be beneficial for cardiovascular function, persistent activation of DDR promotes the onset and development of CVDs. Moreover, therapeutic interventions that target DNA damage and DDR have the potential to attenuate cardiovascular dysfunction and improve disease outcome. In this review, we will discuss molecular mechanisms of DNA damage and repair in the onset and development of CVDs, and explore how DDR in specific cardiac cell types contributes to CVDs. Moreover, we will highlight the latest advances regarding the potential therapeutic strategies targeting DNA damage signalling in CVDs.

Serine mutations in overexpressed Hsp27 abrogate the protection against doxorubicin-induced p53-dependent cardiac apoptosis in mice

Small heat shock proteins (sHsps) protect the heart from chemotherapeutics-induced heart failure by inhibiting p53-dependent apoptosis. However, mechanism of such protection has not been elucidated yet. Here we test a hypothesis that serine phosphorylation of sHsps is essential to inhibit the doxorubicin-induced and p53-dependent apoptotic pathway. Three transgenic mice (TG) lines with cardiomyocyte-specific overexpression of human heat shock protein 27 (hHsp27), namely, wild-type [myosin heavy chain (MHC)-hHsp27], S82A single mutant [MHC-mut-hHsp27(S82A)], and trimutant [MHC-mut-hHsp27(S15A/S78A/S82A)] were generated. TG mice were treated with Dox (6 mg/kg body wt; once in a week; 4 wk) along with age-matched nontransgenic (non-TG) controls. The Dox-treated MHC-hHsp27 mice showed improved survival and cardiac function (both MRI and echocardiography) in terms of contractility [ejection fraction (%EF)] and left ventricular inner diameter (LVID) compared with the Dox-treated non-TG mice. However, both MHC-mut-hHsp27(S82A) and MHC-mut-hHsp27(S15A/S78A/S82A) mutants overexpressing TG mice did not show such a cardioprotection. Furthermore, transactivation of p53 was found to be attenuated only in Dox-treated MHC-hHsp27 mice-derived cardiomyocytes in vitro, as low p53 was detected in the nuclei, not in mutant hHsp27 overexpressing cardiomyocytes. Similarly, only in MHC-hHsp27 overexpressing cardiomyocytes, low Bax, higher mechanistic target of rapamycin (mTOR) phosphorylation, and low apoptotic poly(ADP-ribose) polymerase-1 (PARP-1) cleavage (89 kDa fragment) were detected. Pharmacological inhibition of p53 was more effective in mutant TG mice compared with MHC-hHsp27 mice. We conclude that phosphorylation of overexpressed Hsp27 at S82 and its association with p53 are essential for the cardioprotective effect of overexpressed Hsp27 against Dox-induced dilated cardiomyopathy. Only phosphorylated Hsp27 protects the heart by inhibiting p53 transactivation.NEW & NOTEWORTHY Requirement of serine phosphorylation in Hsp27 for cardioprotective effect against Dox is tested in various mutants overexpressing mice. Cardioprotective effect was found to be compromised in Hsp27 serine mutants overexpressed mice compared with wild-type overexpressing mice. These results indicate that cancer patients, who carry these mutations, may have higher risk of aggravated cardiomyopathy on treated with cardiotoxic chemotherapeutics such as doxorubicin.

NMCP-2 polysaccharide purified from Morchella conica effectively prevents doxorubicin-induced cardiotoxicity by decreasing cardiomyocyte apoptosis and myocardial oxidative stress

Doxorubicin (DOX) is an anthracycline antibiotic used in the clinical treatment of cancer, but its use is limited due to its cardiotoxic effects. Therefore, it is necessary to explore natural compounds that are effective in protecting against the cardiotoxicity caused by DOX. Neutral Morchella conica polysaccharides-2 (NMCP-2) is a natural polysaccharide with antioxidant activity that was isolated and purified from Morchella conica in our laboratory's previous study. This study aimed to investigate the possible protective effect of NMCP-2 on DOX-induced cardiotoxicity and the potential underlying mechanisms. The model of DOX-induced H9C2 cells and the model of DOX-induced mice were used in this study. In in vitro studies of H9C2 myocardial cells, NMCP-2 effectively increased the activity of H9C2 cells, reducing the levels of lactate dehydrogenase (LDH). In the mouse model of DOX-induced chronic cardiotoxicity, NMCP-2 significantly reduced the cardiac index, reduced the release of serum cardiac enzymes, and improved the pathology of murine myocardial tissues, thereby alleviating DOX-induced cardiotoxicity. Further mechanism studies showed that pretreatment with NMCP-2 counteracted the oxidative stress induced by DOX, as indicated by increasing superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) activities, and malondialdehyde (MDA) production decreased. In addition, we observed NMCP-2 inhibited the activation of the mitochondrial apoptosis pathway and regulated the disordered expression of Bcl-2 and Bax in the myocardial tissues of DOX-treated mice. These findings indicated that NMCP-2, a natural bioactive compound, could potentially be used as a food supplement to reduce the cardiotoxicity caused by DOX.

Doxorubicin nanomedicine based on ginsenoside Rg1 with alleviated cardiotoxicity and enhanced antitumor activity

Aim: The authors aimed to develop Dox@Rg1 nanoparticles with decreased cardiotoxicity to expand their application in cancer. Materials & methods: Dox@Rg1 nanoparticles were developed by encapsulating doxorubicin (Dox) in a self-assembled Rg1. The antitumor effect of the nanoparticles was estimated using 4T1 tumor-bearing mice and the protective effect on the heart was investigated in vitro and in vivo. Results: Different from Dox, the Dox@Rg1 nanoparticles induced increased cytotoxicity to tumor cells, which was decreased in cardiomyocytes by the inhibition of apoptosis. The study in vivo revealed that the Dox@Rg1 nanoparticles presented a perfect tumor-targeting ability and improved antitumor effects. Conclusion: Dox@Rg1 nanoparticles could enhance the antitumor effects and decrease the cardiotoxicity of Dox.

Cardiotoxicity of Cancer Treatments: Focus on Anthracycline Cardiomyopathy

Significant progress has been made in developing new treatments and refining the use of preexisting ones against cancer. Their successful use and the longer survival of cancer patients have been associated with reports of new cardiotoxicities and the better characterization of the previously known cardiac complications. Immunotherapies with monoclonal antibodies against specific cancer-promoting genes, chimeric antigen receptor T cells, and immune checkpoint inhibitors have been developed to fight cancer cells, but they can also show off-target effects on the heart. Some of these cardiotoxicities are thought to be due to nonspecific immune activation and inflammatory damage. Unlike immunotherapy-associated cardiotoxicities which are relatively new entities, there is extensive literature on anthracycline-induced cardiomyopathy. Here, we provide a brief overview of the cardiotoxicities of immunotherapies for the purpose of distinguishing them from anthracycline cardiomyopathy. This is especially relevant as the expansion of oncological treatments presents greater diagnostic challenges in determining the cause of cardiac dysfunction in cancer survivors with a history of multiple cancer treatments including anthracyclines and immunotherapies administered concurrently or serially over time. We then provide a focused review of the mechanisms proposed to underlie the development of anthracycline cardiomyopathy based on experimental data mostly in mouse models. Insights into its pathogenesis may stimulate the development of new strategies to identify patients who are susceptible to anthracycline cardiomyopathy while permitting low cardiac risk patients to receive optimal treatment for their cancer.

Geraniol isolated from lemon grass to mitigate doxorubicin-induced cardiotoxicity through Nrf2 and NF-κB signaling

BACKGROUND

Geraniol, a natural monoterpene, is a component of many plant essential oils. It contains many medicinal and pharmacological properties. Doxorubicin is an anticancer drug; however, its clinical usage is limited due to its cumulative and dose-dependent cardiotoxicity. This study investigates geraniol as a protective agent against doxorubicin-induced cardiotoxicity and explores possible underlying mechanisms of action.

METHODS

Male Sprague-Dawley rats were allocated into five groups. Groups 1 and 2 were administered saline and geraniol 200 mg/kg/day/orally, respectively, for 15 days. Group 3 was administered intraperitoneal doxorubicin (5 mg/kg/IP on the 5th, 10th and 15th days to achieve a cumulative dose of 15 mg/kg) to induce cardiotoxicity. The fourth and fifth groups were treated with either geraniol 100 mg/kg or 200 mg/kg orally and doxorubicin to equal the doxorubicin dose administered to Group 3.

RESULTS

Treatment with geraniol significantly ameliorated cardiac damage and restored serum cardiac injury marker levels in doxorubicin treated animals. Geraniol upregulated Nrf2 and HO-1 expression, elevated total antioxidant capacity, decreased the nuclear accumulation of kappa-light-chain enhancer of activated B cells (NF-κB), decreased the phosphorylation and degradation of nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκBα), suppressed tumor necrosis factor-alpha (TNF-α), interleukin 1 beta (IL-1β), and interleukin-18 (IL-18) levels, and restored the levels of Bax and caspase-3 and 9 in heart tissue.

CONCLUSION

Geraniol may function as a potential activator of nuclear factor erythroid 2-related factor 2 (Nrf2), which subsequently improves Nrf2-dependent antioxidative signaling, diminishes apoptosis and subdues the inflammatory response. The downstream result is protection of the heart from doxorubicin-induced cardiotoxicity.

Exosomal Micro-RNA-96 Derived From Bone Marrow Mesenchymal Stem Cells Inhibits Doxorubicin-Induced Myocardial Toxicity by Inhibiting the Rac1/Nuclear Factor-κB Signaling Pathway

Background

Exosomes are small membranous structures released from cells into the blood, regulating various biological processes. However, the role of exosomes in cardiotoxicity remains largely unclear. This study investigated the functional mechanism of exosomal microRNA‐96 (miR‐96) derived from bone marrow mesenchymal stem cells (BMSCs) in myocardial toxicity induced by doxorubicin.

Methods and Results

BMSCs were transfected with miR‐96 mimic, miR‐96 inhibitor, or the negative control before exosome isolation. The functional mechanism of BMSC‐derived exosomal miR‐96 was investigated in doxorubicin‐induced cell and rat models. The cardiac function, histological morphology, and fiber content of myocardium were examined. The expression levels of the following biomarkers were measured for assessment of cardiac injury: creatine kinase isoenzyme MB, cardiac troponin I, brain natriuretic peptide, soluble suppression of tumorigenesis‐2, tumor necrosis factor‐α, interleukin‐1β, interleukin‐6, superoxide dismutase, glutathione peroxidase, and malondialdehyde. Cell Counting Kit‐8 assay was used to measure the survival rate of cardiomyocytes. The expressions of miR‐96, Rac1, p‐IKKα/IKKα, p‐IKKβ/IKKβ, p‐IκBα/IκBα and p‐p65/p65 in myocardium and cardiomyocytes were also assessed. The targeting relationship between miR‐96 and Rac1 was verified by dual‐luciferase reporter assay. miR‐96 was downregulated, Rac1 was upregulated and the nuclear factor‐κB signaling pathway was activated in doxorubicin‐induced cell and animal models. Doxorubicin decreased antioxidative enzymes (superoxide dismutase and glutathione peroxidase) and increased myocardial injury biomarkers (creatine kinase isoenzyme MB, cardiac troponin I, and brain natriuretic peptide), proinflammatory cytokines (tumor necrosis factor‐α, interleukin‐1β, and interleukin‐6), malondialdehyde, and myocardial fibers. Exosomes derived from BMSCs ameliorated doxorubicin‐induced myocardial injuries. Overexpression of miR‐96 in exosomes derived from BMSCs further enhanced the protection of myocardium and cardiomyocytes against doxorubicin‐induced toxicity while miR‐96 knockdown abolished the protective effects of exosomes derived from BMSCs. Rac1 was a target gene of miR‐96. Rac1 inhibition could downregulate the expression of the nuclear factor‐κB signaling and further reverse the promotion of miR‐96 knockdown on doxorubicin‐induced myocardial toxicity.

Conclusions

BMSC‐derived exosomal miR‐96 protects myocardium against doxorubicin‐induced toxicity by inhibiting the Rac/nuclear factor‐κB signaling pathway.

Synergistic Combination of Bioactive Hydroxyapatite Nanoparticles and the Chemotherapeutic Doxorubicin to Overcome Tumor Multidrug Resistance

Multidrug resistance (MDR) is one of the biggest obstacles in cancer chemotherapy. Here, a remarkable reversal of MDR in breast cancer through the synergistic effects of bioactive hydroxyapatite nanoparticles (HAPNs) and doxorubicin (DOX) is shown. DOX loaded HAPNs (DHAPNs) exhibit a 150-fold reduction in IC₅₀ compared with free DOX for human MDR breast cancer MCF-7/ADR cells, and lead to almost complete inhibition of tumor growth in vivo without obvious side effects of free DOX. This high efficacy and specificity could be attributed to multiple action mechanisms of HAPNs. In addition to acting as the conventional nanocarriers to facilitate the cellular uptake and retention of DOX in MCF-7/ADR cells, more importantly, drug-free HAPNs themselves are able to prevent drug being pumped out of MDR cells through targeting mitochondria to induce mitochondrial damage and inhibit ATP production and to trigger sustained mitochondrial calcium overload and apoptosis in MDR cancer cells while not affecting normal cells. The results demonstrate that this simple but versatile bioactive nanoparticle provides a practical approach to effectively overcome MDR.

Alamandine significantly reduces doxorubicin-induced cardiotoxicity in rats

Doxorubicin (DOX) is an anthracycline antibiotic. Despite its unwanted side effects, it has been successfully used in tumor therapy. Given that oxidative stress and inflammatory factors are essential to cardiotoxicity caused by DOX, we assumed that alamandine, which enhances endogenous antioxidants and has anti-inflammatory effects, may prevent DOX-induced cardiotoxicity. Rats received DOX (3.75 mg/kg) i.p on days 14, 21, 28, and 35 (total cumulative dose = 15 mg/kg) and alamandine (50 μg/kg/day) via mini-osmotic pumps for 42 days. At the end of the 42-day period, we evaluated hemodynamic parameters, electrocardiogram, cardiac troponin I (cTnI), superoxidase dismutase (SOD), total antioxidant capacity (TAC), malondialdehyde (MDA), inflammatory cytokines (tumor necrosis factor-α (TNF-α), IL-1β, NF-κB), apoptosis markers (caspase 3), and histopathology of haemotoxylin- and eosin-stained cardiac muscle fibers were evaluated. DOX significantly increased QT, corrected QT (QTc), and RR intervals. Alamandine co-therapy prevented ECG changes. Alamandine administration restored DOX-induced disruptions in the cardiac muscle architecture and vascular congestion. Alamandine co-therapy also alleviated other effects of DOX, including cardiac contractility, decreased systolic and diastolic blood pressure, and increased left ventricular end-diastolic pressure. Moreover, alamandine co-therapy substantially decreased the elevation of oxidative stress markers, inflammatory cytokines, and caspase 3 in DOX-treated rats. The results suggest that alamandine reduced DOX-induced cardiotoxicity via antioxidant, anti-inflammatory, and anti-apoptotic activities.

Mechanisms of doxorubicin-mediated reproductive toxicity - A review

The anticancer drug doxorubicin has been associated with several adverse side-effects including reproductive toxicity in both genders. The current review has complied the mechanisms of doxorubicin induced reproductive toxicity. The articles cited in the review were searched using Google Scholar, PubMed, Scopus, Science Direct. Doxorubicin treatment has been found to cause a decrease in testicular mass along with histopathological deformities, oligospermia and abnormalities in sperm morphology. Apart from severely affecting the normal physiological role of both Leydig cells and Sertoli cells, doxorubicin also causes chromosome abnormalities and affects DNA methylase enzyme. Testicular lipid metabolism has been found to be negatively affected by doxorubicin treatment resulting in altered profile of sphingolipids glycerophospholipids and neutral lipids. Dysregulation of 3β-hydroxysteroid dehydrogenase (3β-HSD) and 17β- hydroxysteroid dehydrogenase (17β-HSD) are strongly linked to testicular exposure to doxorubicin. Further, oxidative stress along with endoplasmic reticulum stress are also found to aggravate the male reproductive functioning in doxorubicin treated conditions. Several antioxidant enzymes such as superoxide dismutase, catalase, glutathione peroxidase (GPx) are downregulated by doxorubicin. It also disturbs the hormones of the hypothalamic-pituitary-gonadal (HPG)-axis including testosterone, luteinizing hormone, follicle stimulating hormone etc. In females, the drug disturbs folliculogenesis and oogenesis leading to failure of ovulation and uterine cycle. In rodent model the drug shortens pro-estrous and estrous phases. It was also found that doxorubicin causes mitochondrial dysfunction in oocytes with impaired calcium signaling along with ER stress. The goal of the present review is to comprehends various pathways due to which doxorubicin treatment promotes toxicity in male and female reproductive system.

HSP27 role in cardioprotection by modulating chemotherapeutic doxorubicin-induced cell death

The common phenomenon expected from any anti-cancer drug in use is to kill the cancer cells without any side effects to non-malignant cells. Doxorubicin is an anthracycline derivative anti-cancer drug active over different types of cancers with anti-cancer activity but attributed to unintended cytotoxicity and genotoxicity triggering mitogenic signals inducing apoptosis. Administration of doxorubicin tends to both acute and chronic toxicity resulting in cardiomyopathy (left ventricular dysfunction) and congestive heart failure (CHF). Cardiotoxicity is prevented through administration of different cardioprotectants along with the drug. This review elaborates on mechanism of drug-mediated cardiotoxicity and attenuation principle by different cardioprotectants, with a focus on Hsp27 as cardioprotectant by prevention of drug-induced oxidative stress, cell survival pathways with suppression of intrinsic cell death. In conclusion, Hsp27 may offer an exciting/alternating cardioprotectant, with a wider study being need of the hour, specifically on primary cell line and animal models in conforming its cardioprotectant behaviour.

The regulatory roles of p53 in cardiovascular health and disease

Cardiovascular disease (CVD) remains the leading cause of mortality globally, so further investigation is required to identify its underlying mechanisms and potential targets for its prevention. The transcription factor p53 functions as a gatekeeper, regulating a myriad of genes to maintain normal cell functions. It has received a great deal of research attention as a tumor suppressor. In the past three decades, evidence has also shown a regulatory role for p53 in the heart. Basal p53 is essential for embryonic cardiac development; it is also necessary to maintain normal heart architecture and physiological function. In pathological cardiovascular circumstances, p53 expression is elevated in both patient samples and animal models. Elevated p53 plays a regulatory role via anti-angiogenesis, pro-programmed cell death, metabolism regulation, and cell cycle arrest regulation. This largely promotes the development of CVDs, particularly cardiac remodeling in the infarcted heart, hypertrophic cardiomyopathy, dilated cardiomyopathy, and diabetic cardiomyopathy. Roles for p53 have also been found in atherosclerosis and chemotherapy-induced cardiotoxicity. However, it has different roles in cardiomyocytes and non-myocytes, even in the same model. In this review, we describe the different effects of p53 in cardiovascular physiological and pathological conditions, in addition to potential CVD therapies targeting p53.

Anthracycline-induced cardiomyopathy: cellular and molecular mechanisms

Despite the known risk of cardiotoxicity, anthracyclines are widely prescribed chemotherapeutic agents. They are broadly characterized as being a robust effector of cellular apoptosis in rapidly proliferating cells through its actions in the nucleus and formation of reactive oxygen species (ROS). And, despite the early use of dexrazoxane, no effective treatment strategy has emerged to prevent the development of cardiomyopathy, despite decades of study, suggesting that much more insight into the underlying mechanism of the development of cardiomyopathy is needed. In this review, we detail the specific intracellular activities of anthracyclines, from the cell membrane to the sarcoplasmic reticulum, and highlight potential therapeutic windows that represent the forefront of research into the underlying causes of anthracycline-induced cardiomyopathy.

Protective effects of medicinal plant against diabetes induced cardiac disorder: A review

ETHNOPHARMACOLOGY RELEVANCE

Nowadays, there is an increase in global tendency to use medicinal plants as preventive and therapeutic agents to manage diabetes and its long-term complications such as cardiovascular disorders owing to their availability and valuable traditional background.

AIM OF STUDY

This review aims to introduce common medicinal plants, which have been demonstrated to have cardioprotective effects on diabetes and their mechanisms of action.

MATERIALS AND METHODS

Online literature databases, including Web of Sciences, PubMed, Science Direct, Scopus and Google Scholar were searched without date limitation by May 2020. The following keywords (natural products or medicinal plants or herbal medicine or herb or extract) and (diabetes or antidiabetic or hyperglycemic) and (cardiomyopathy or heart or cardioprotective or cardiac or cardio) were used, and after excluding non-relevant articles, 81 original English articles were selected.

RESULTS

The surveyed medicinal plants induced cardioprotective effects mostly through increasing antioxidant effects leading to attenuating ROS production as well as by inhibiting inflammatory signaling pathways and related cytokines. Moreover, they ameliorated the Na+/K + ATPase pump, the L-type Ca₂⁺ channel current, and the intracellular ATP. They also reduced cardiac remodeling and myocardial cell apoptosis through degradation of caspase-3, Bax, P53 protein, enhancement of Bcl-2 protein expression as well as downregulation of TGFβ1 and TNFα expression. In addition, the extracts improved cardiac function through increasing EF% and FS% as well as restoring hemodynamic parameters.

CONCLUSIONS

The reviewed medicinal plants demonstrated cardioprotective manifestations in diabetes through intervention with mechanisms involved in the diabetic heart to restore cardiovascular complications.

Role of Oxidative Stress in the Mechanisms of Anthracycline-Induced Cardiotoxicity: Effects of Preventive Strategies

Anthracycline-induced cardiotoxicity (AIC) persists as a significant cause of morbidity and mortality in cancer survivors. Although many protective strategies have been evaluated, cardiotoxicity remains an ongoing threat. The mechanisms of AIC remain unclear; however, several pathways have been proposed, suggesting a multifactorial origin. When the central role of topoisomerase 2β in the pathophysiology of AIC was described some years ago, the classical reactive oxygen species (ROS) hypothesis shifted to a secondary position. However, new insights have reemphasized the importance of the role of oxidative stress-mediated signaling as a common pathway and a critical modulator of the different mechanisms involved in AIC. A better understanding of the mechanisms of cardiotoxicity is crucial for the development of treatment strategies. It has been suggested that the available therapeutic interventions for AIC could act on the modulation of oxidative balance, leading to a reduction in oxidative stress injury. These indirect antioxidant effects make them an option for the primary prevention of AIC. In this review, our objective is to provide an update of the accumulated knowledge on the role of oxidative stress in AIC and the modulation of the redox balance by potential preventive strategies.

Genotoxins exaggerate the stressed state of aneuploid embryonic stem cells via activation of autophagy

The cellular consequences of aneuploidy are largely dependent on the cell types examined. Aneuploid yeasts and mouse embryonic fibroblasts exhibit cell proliferation defects and can be selectively inhibited by compounds that cause proteotoxic or energy stress. By contrast, most aneuploid pluripotent stem cells proliferate rapidly and reach higher saturation densities. The responses of aneuploid pluripotent stem cells to the stress-inducing compounds remain uncharacterized. Here, we tested the response of aneuploid embryonic stem cells to several compounds that caused proteotoxic, energy and genotoxic stress using previously established mouse embryonic stem cell lines trisomic for chromosome 6, 8, 11, or 15. Not all trisomic embryonic stem cells were selectively inhibited by compounds that cause proteotoxic or energy stress. However, most of these cells exhibited increased sensitivity to genotoxins. They displayed elevated DNA damage response as characterized by increased γH2A.X foci under genotoxic stress. Further investigations indicated that elevated autophagy levels might contribute to the increased cytotoxic effects of genotoxins on trisomic embryonic stem cells. Our study laid the foundation for eliminating aneuploidy that might be an effective approach for controlling cancer progression.

Signaling Pathways Underlying Anthracycline Cardiotoxicity

Significance: The cardiac side effects of hematological treatments are a major issue of the growing population of cancer survivors, often affecting patient survival even more than the tumor for which the treatment was initially prescribed. Among the most cardiotoxic drugs are anthracyclines (ANTs), highly potent antitumor agents, which still represent a mainstay in the treatment of hematological and solid tumors. Unfortunately, diagnosis, prevention, and treatment of cardiotoxicity are still unmet clinical needs, which call for a better understanding of the molecular mechanism behind the pathology. Recent Advances: This review article will discuss recent findings on the pathomechanisms underlying the cardiotoxicity of ANTs, spanning from DNA and mitochondrial damage to calcium homeostasis, autophagy, and apoptosis. Special emphasis will be given to the role of reactive oxygen species and their interplay with major signaling pathways. Critical Issues: Although new promising therapeutic targets and new drugs have started to be identified, their efficacy has been mainly proven in preclinical studies and requires clinical validation. Future Directions: Future studies are awaited to confirm the relevance of recently uncovered targets, as well as to identify new druggable pathways, in more clinically relevant models, including, for example, human induced pluripotent stem cell-derived cardiomyocytes.

The Role of AMPK Activation for Cardioprotection in Doxorubicin-Induced Cardiotoxicity

Doxorubicin is a commonly used chemotherapeutic agent for the treatment of a range of cancers, but despite its success in improving cancer survival rates, doxorubicin is cardiotoxic and can lead to congestive heart failure. Therapeutic options for this patient group are limited to standard heart failure medications with the only drug specific for doxorubicin cardiotoxicity to reach FDA approval being dexrazoxane, an iron-chelating agent targeting oxidative stress. However, dexrazoxane has failed to live up to its expectations from preclinical studies while also bringing up concerns about its safety. Despite decades of research, the molecular mechanisms of doxorubicin cardiotoxicity are still poorly understood and oxidative stress is no longer considered to be the sole evil. Mitochondrial impairment, increased apoptosis, dysregulated autophagy and increased fibrosis have also been shown to be crucial players in doxorubicin cardiotoxicity. These cellular processes are all linked by one highly conserved intracellular kinase: adenosine monophosphate-activated protein kinase (AMPK). AMPK regulates mitochondrial biogenesis via PGC1α signalling, increases oxidative mitochondrial metabolism, decreases apoptosis through inhibition of mTOR signalling, increases autophagy through ULK1 and decreases fibrosis through inhibition of TGFβ signalling. AMPK therefore sits at the control point of many mechanisms shown to be involved in doxorubicin cardiotoxicity and cardiac AMPK signalling itself has been shown to be impaired by doxorubicin. In this review, we introduce different agents known to activate AMPK (metformin, statins, resveratrol, thiazolidinediones, AICAR, specific AMPK activators) as well as exercise and dietary restriction, and we discuss the existing evidence for their potential role in cardioprotection from doxorubicin cardiotoxicity.

Distinct influence of the anthracycline derivative doxorubicin on the differentiation efficacy of mESC-derived endothelial progenitor cells

Cardiotoxicity is a highly relevant, because often life-threatening, adverse effect of doxorubicin (Doxo)-based anticancer therapy. Here, we investigated the Doxo-response of cardiovascular stem/progenitor cells employing a mouse embryonic stem cell (mESC)-based in vitro differentiation model. Endothelial progenitor cells revealed a pronounced Doxo sensitivity as compared to mESC, differentiated endothelial-like (EC) and cardiomyocyte-like cells (CM) and CM progenitors, which rests on the activation of senescence. Doxo treatment of EC progenitors altered protein expression of individual endothelial markers, actin cytoskeleton morphology, mRNA expression of genes related to mitochondrial functions, autophagy, apoptosis, and DNA repair as well as mitochondrial DNA content, respiration and ATP production in the surviving differentiated EC progeny. By contrast, LDL uptake, ATP-stimulated Ca²⁺ release, and cytokine-stimulated ICAM-1 expression remained unaffected by the anthracycline treatment. Thus, exposure of EC progenitors to Doxo elicits isolated and persistent dysfunctions in the surviving EC progeny. In conclusion, we suggest that Doxo-induced injury of EC progenitors adds to anthracycline-induced cardiotoxicity, making this cell-type a preferential target for pharmacoprotective and regenerative strategies.

miR-26a attenuates cardiac apoptosis and fibrosis by targeting ataxia-telangiectasia mutated in myocardial infarction

Apoptosis and fibrosis play a vital role in myocardial infarction (MI) induced tissue injury. Although microRNAs have been the focus of many studies on cardiac apoptosis and fibrosis in MI, the detailed effects of miR-26a is needed to further understood. The present study demonstrated that miR-26a was downregulated in ST-elevation MI (STEMI) patients and oxygen-glucose deprivation (OGD)-treated H9c2 cells. Downregulation of miR-26a was closely correlated with the increased expression of creatine kinase, creatine kinase-MB and troponin I in STEMI patients. Further analysis identified that ataxia-telangiectasia mutated (ATM) was a target gene for miR-26a based on a bioinformatics analysis. miR-26a overexpression effectively reduced ATM expression, apoptosis, and apoptosis-related proteins in OGD-treated H9c2 cells. In a mouse model of MI, the expression of miR-26a was significantly decreased in the infarct zone of the heart, whereas apoptosis and ATM expression were increased. miR-26a overexpression effectively reduced ATM expression and cardiac apoptosis at Day 1 after MI. Furthermore, we demonstrated that overexpression of miR-26a improved cardiac function and reduced cardiac fibrosis by the reduced expression of collagen type I and connective tissue growth factor (CTGF) in mice at Day 14 after MI. Overexpression of miR-26a or ATM knockdown decreased collagen I and CTGF expression in cultured OGD-treated cardiomyocytes. Taken together, these data demonstrate a prominent role for miR-26a in linking ATM expression to ischemia-induced apoptosis and fibrosis, key features of MI progression. miR-26a reduced MI development by affecting ATM expression and could be targeted in the treatment of MI.

DNA-PKcs promotes cardiac ischemia reperfusion injury through mitigating BI-1-governed mitochondrial homeostasis

DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is a novel inducer to promote mitochondrial apoptosis and suppress tumor growth in a variety of cells although its role in cardiovascular diseases remains obscure. This study was designed to examine the role of DNA-PKcs in cardiac ischemia reperfusion (IR) injury and mitochondrial damage. Cardiomyocyte-specific DNA-PKcs knockout (DNA-PKcs^CKO) mice were subjected to IR prior to assessment of myocardial function and mitochondrial apoptosis. Our data revealed that IR challenge, hypoxia-reoxygenation (HR) or H₂O₂-activated DNA-PKcs through post-transcriptional phosphorylation in murine hearts or cardiomyocytes. Mice deficient in DNA-PKcs in cardiomyocytes were protected against cardiomyocyte death, infarct area expansion and cardiac dysfunction. DNA-PKcs ablation countered IR- or HR-induced oxidative stress, mPTP opening, mitochondrial fission, mitophagy failure and Bax-mediated mitochondrial apoptosis, possibly through suppression of Bax inhibitor-1 (BI-1) activity. A direct association between DNA-PKcs and BI-1 was noted where DNA-PKcs had little effect on BI-1 transcription but interacted with BI-1 to promote its degradation. Loss of DNA-PKcs stabilized BI-1, thus offering resistance of mitochondria and cardiomyocytes against IR insult. Moreover, DNA-PKcs ablation-induced beneficial cardioprotection against IR injury was mitigated by concurrent knockout of BI-1. Double deletion of DNA-PKcs and BI-1 failed to exert protection against global IR injury and mitochondrial damage, confirming a permissive role of BI-1 in DNA-PKcs deletion-elicited cardioprotection against IR injury. DNA-PKcs serves as a novel causative factor for mitochondrial damage via suppression of BI-1, en route to the onset and development of cardiac IR injury.

Translationally controlled tumor protein (TCTP) plays a pivotal role in cardiomyocyte survival through a Bnip3-dependent mechanism

Prevention of cardiomyocyte death is an important therapeutic strategy for heart failure. In this study, we focused on translationally controlled tumor protein (TCTP), a highly conserved protein that is expressed ubiquitously in mammalian tissues, including heart. TCTP plays pivotal roles in survival of certain cell types, but its function in cardiomyocytes has not been examined. We aimed to clarify the role of TCTP in cardiomyocyte survival and the underlying mechanism. Here, we demonstrated that downregulation of TCTP with siRNA induced cell death of cardiomyocytes with apoptotic and autophagic features, accompanied with mitochondrial permeability transition pore (mPTP) opening. TCTP loss did not induce cell death of cardiac fibroblasts. Bcl-2/adenovirus E1B 19-kDa interacting protein 3 (Bnip3) was found to mediate the TCTP-loss-induced cardiomyocyte death. In exploring the clinical significance of the TCTP expression in the heart, we found that DOX treatment markedly downregulated the protein expression of TCTP in cultured cardiomyocytes and in mouse heart tissue. Exogenous rescue of TCTP expression attenuated DOX-induced cardiomyocyte death. In mice, cardiomyocyte-specific overexpression of TCTP resulted in decreased susceptibility to DOX-induced cardiac dysfunction, accompanied with attenuated induction of Bnip3. Dihydroartemisinin, a pharmacological TCTP inhibitor, induced development of heart failure and cardiomyocyte death in control mice, but not in mice with cardiomyocyte-specific TCTP overexpression. Our findings revealed TCTP has a pivotal role in cardiomyocyte survival, at least in part through a Bnip3-dependent mechanism. TCTP could be considered as a candidate therapeutic target to prevent DOX-induced heart failure.

Role of oxidative stress in cardiotoxicity of antineoplastic drugs

Tumors and heart disease are two of the leading causes of human death. With the development of anti-cancer therapy, the survival rate of cancer patients has been significantly improved. But at the same time, the incidence of cardiovascular adverse events caused by cancer treatment has also been considerably increased, such as arrhythmia, left ventricular (LV) systolic and diastolic dysfunction, and even heart failure (HF), etc., which seriously affects the quality of life of cancer patients. More importantly, the occurrence of adverse events may lead to the adjustment or the cessation of anti-cancer treatment, which affects the survival rate of patients. Understanding the mechanism of cardiotoxicity (CTX) induced by antineoplastic drugs is the basis of adequate protection of the heart without impairing the efficacy of antineoplastic therapy. Based on current research, a large amount of evidence has shown that oxidative stress (OS) plays an essential role in CTX induced by antineoplastic drugs and participates in its toxic reaction directly and indirectly. Here, we will review the mechanism of action of OS in cardiac toxicity of antineoplastic drugs, to provide new ideas for researchers, and provide further guidance for clinical prevention and treatment of cardiac toxicity of anti-tumor drugs in the future.