Early biomarkers of doxorubicin-induced heart injury in a mouse model

miRNA Expression Profiles in Isolated Ventricular Cardiomyocytes: Insights into Doxorubicin-Induced Cardiotoxicity

Doxorubicin (DOX), widely used as a chemotherapeutic agent for various cancers, is limited in its clinical utility by its cardiotoxic effects. Despite its widespread use, the precise mechanisms underlying DOX-induced cardiotoxicity at the cellular and molecular levels remain unclear, hindering the development of preventive and early detection strategies. To characterize the cytotoxic effects of DOX on isolated ventricular cardiomyocytes, focusing on the expression of specific microRNAs (miRNAs) and their molecular targets associated with endogenous cardioprotective mechanisms such as the ATP-sensitive potassium channel (KATP), Sirtuin 1 (SIRT1), FOXO1, and GSK3β. We isolated Guinea pig ventricular cardiomyocytes by retrograde perfusion and enzymatic dissociation. We assessed cell morphology, Reactive Oxygen Species (ROS) levels, intracellular calcium, and mitochondrial membrane potential using light microscopy and specific probes. We determined the miRNA expression profile using small RNAseq and validated it using stem-loop qRT-PCR. We quantified mRNA levels of some predicted and validated molecular targets using qRT-PCR and analyzed protein expression using Western blot. Exposure to 10 µM DOX resulted in cardiomyocyte shortening, increased ROS and intracellular calcium levels, mitochondrial membrane potential depolarization, and changes in specific miRNA expression. Additionally, we observed the differential expression of KATP subunits (ABCC9, KCNJ8, and KCNJ11), FOXO1, SIRT1, and GSK3β molecules associated with endogenous cardioprotective mechanisms. Supported by miRNA gene regulatory networks and functional enrichment analysis, these findings suggest that DOX-induced cardiotoxicity disrupts biological processes associated with cardioprotective mechanisms. Further research must clarify their specific molecular changes in DOX-induced cardiac dysfunction and investigate their diagnostic biomarkers and therapeutic potential.

Circulating microRNAs and therapy-associated cardiac events in HER2-positive breast cancer patients: an exploratory analysis from NeoALTTO

PURPOSE

The relevance of cardiotoxicity in the context of HER2-positive breast cancer is likely to increase with increasing patient treatment exposure, number of treatment lines, and prolonged survival. Circulating biomarkers to early identify patients at risk of cardiotoxicity could allow personalized treatment and follow-up measures. The aim of this study is to examine the relationship between circulating microRNAs and adverse cardiac events in HER2-positive breast cancer patients.

METHODS

We based our work on plasma samples from NeoALTTO trial obtained at baseline, after 2 weeks of anti-HER2 therapy, and immediately before surgery. Eleven patients experienced either a symptomatic or asymptomatic cardiac event. Circulating microRNAs were profiled in all patients presenting a cardiac event (case) and in an equal number of matched patients free of reported cardiac events (controls) using microRNA-Ready-to-Use PCR (Human panel I + II). Sensitivity analyses were performed by increasing the number of controls to 1:2 and 1:3. Normalized microRNA expression levels were compared between cases and controls using the non-parametric Kruskal-Wallis test.

RESULTS

Eight circulating microRNAs resulted differentially expressed after 2 weeks of anti-HER2 therapy between patients experiencing or not a cardiac event. Specifically, the expression of miR-125b-5p, miR-409-3p, miR-15a-5p, miR-423-5p, miR-148a-3p, miR-99a-5p, and miR-320b increased in plasma of cases as compared to controls, while the expression of miR-642a-5p decreases. Functional enrichment analysis revealed that all these microRNAs were involved in cardiomyocyte adrenergic signaling pathway.

CONCLUSION

This study provides proof of concept that circulating microRNAs tested soon after treatment start could serve as biomarkers of cardiotoxicity in a very early stage in breast cancer patients receiving anti-HER2 therapy.

Mechanisms of Cardiovascular Toxicities Induced by Cancer Therapies and Promising Biomarkers for Their Prediction: A Scoping Review

AIM

With the advancement of anti-cancer medicine, cardiovascular toxicities due to cancer therapies are common in oncology patients, resulting in increased mortality and economic burden. Cardiovascular toxicities caused by cancer therapies include different severities of cardiomyopathy, arrhythmia, myocardial ischaemia, hypertension, and thrombosis, which may lead to left ventricular dysfunction and heart failure. This scoping review aimed to summarise the mechanisms of cardiovascular toxicities following various anti-cancer treatments and potential predictive biomarkers for early detection.

METHODS

PubMed, Cochrane, Embase, Web of Science, Scopus, and CINAHL databases were searched for original studies written in English related to the mechanisms of cardiovascular toxicity induced by anti-cancer therapies, including chemotherapy, targeted therapy, immunotherapy, radiation therapy, and relevant biomarkers. The search and title/abstract screening were conducted independently by two reviewers, and the final analysed full texts achieved the consensus of the two reviewers.

RESULTS

A total of 240 studies were identified based on their titles and abstracts. In total, 107 full-text articles were included in the analysis. Cardiomyocyte and endothelial cell apoptosis caused by oxidative stress injury, activation of cell apoptosis, blocking of normal cardiovascular protection signalling pathways, overactivation of immune cells, and myocardial remodelling were the main mechanisms. Promising biomarkers for anti-cancer therapies related to cardiovascular toxicity included placental growth factor, microRNAs, galectin-3, and myeloperoxidase for the early detection of cardiovascular toxicity.

CONCLUSION

Understanding the mechanisms of cardiovascular toxicity following various anti-cancer treatments could provide implications for future personalised treatment methods to protect cardiovascular function. Furthermore, specific early sensitive and stable biomarkers of cardiovascular system damage need to be identified to predict reversible damage to the cardiovascular system and improve the effects of anti-cancer agents.

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.

MicroRNA in the Diagnosis and Treatment of Doxorubicin-Induced Cardiotoxicity

Doxorubicin (DOX), a broad-spectrum chemotherapy drug, is widely applied to the treatment of cancer; however, DOX-induced cardiotoxicity (DIC) limits its clinical therapeutic utility. However, it is difficult to monitor and detect DIC at an early stage using conventional detection methods. Thus, sensitive, accurate, and specific methods of diagnosis and treatment are important in clinical practice. MicroRNAs (miRNAs) belong to non-coding RNAs (ncRNAs) and are stable and easy to detect. Moreover, miRNAs are expected to become biomarkers and therapeutic targets for DIC; thus, there are currently many studies focusing on the role of miRNAs in DIC. In this review, we list the prominent studies on the diagnosis and treatment of miRNAs in DIC, explore the feasibility and difficulties of using miRNAs as diagnostic biomarkers and therapeutic targets, and provide recommendations for future research.

Non-coding RNAs in cancer therapy-induced cardiotoxicity: Mechanisms, biomarkers, and treatments

As a result of ongoing breakthroughs in cancer therapy, cancer patients' survival rates have grown considerably. However, cardiotoxicity has emerged as the most dangerous toxic side effect of cancer treatment, negatively impacting cancer patients' prognosis. In recent years, the link between non-coding RNAs (ncRNAs) and cancer therapy-induced cardiotoxicity has received much attention and investigation. NcRNAs are non-protein-coding RNAs that impact gene expression post-transcriptionally. They include microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). In several cancer treatments, such as chemotherapy, radiotherapy, and targeted therapy-induced cardiotoxicity, ncRNAs play a significant role in the onset and progression of cardiotoxicity. This review focuses on the mechanisms of ncRNAs in cancer therapy-induced cardiotoxicity, including apoptosis, mitochondrial damage, oxidative stress, DNA damage, inflammation, autophagy, aging, calcium homeostasis, vascular homeostasis, and fibrosis. In addition, this review explores potential ncRNAs-based biomarkers and therapeutic strategies, which may help to convert ncRNAs research into clinical practice in the future for early detection and improvement of cancer therapy-induced cardiotoxicity.

MiRNAs and circRNAs for the Diagnosis of Anthracycline-Induced Cardiotoxicity in Breast Cancer Patients: A Narrative Review

Breast cancer (BC) is the most frequent type of female cancer with increasing incidence in recent years. Doxorubicin (DOX) is an important backbone chemotherapy in BC, responsible for cardiotoxicity (CTX) in about 9% of treated women within the first year. Biomarkers of early CTX diagnosis are essential to avoid complicated DOX-related cardiac diseases. Traditional serum biomarkers are either poorly sensitive with transient elevation, and even absent if investigated outside their diagnostic window, or arise only in late-stage CTX. Emerging biomarkers such as non-coding RNA (ncRNA) have been recently investigated in DOX-related CTX. In our review, we revised the role of microRNAs, the most studied type of ncRNA, both in animal and human models, highlighting the interesting but often contrasting results. Moreover, we reviewed a novel class of ncRNA, circular RNA (circRNA), focusing on their modulatory mechanisms also involving microRNAs. MicroRNA and circRNA are players in a wide homeostatic balance with their perturbation representing a possible compensation for DOX damage. Further studies are required to assess the modalities of early detection of their variation in BC patients suffering from heart disease induced by DOX treatment.

Ultrasmall Nanoparticle Delivery of Doxorubicin Improves Therapeutic Index for High-Grade Glioma

Purpose: Despite dramatic growth in the number of small molecule drugs developed to treat solid tumors, durable therapeutic options to control primary central nervous system malignancies are relatively scarce. Chemotherapeutic agents which appear biologically potent in model systems have often been found to be marginally effective at best when given systemically in clinical trials. This work presents for the first time an ultrasmall (&lt; 8 nm) multimodal core-shell silica nanoparticle, Cornell prime dots (or C' dots), for the efficacious treatment of high-grade gliomas. Experimental Design: This work presents first-in-kind renally-clearable ultrasmall (&lt; 8 nm) multimodal Cornell prime dots (or C' dots) with surface-conjugated doxorubicin via pH-sensitive linkers for the efficacious treatment in two different clinically relevant high-grade glioma models. Results: Optimal drug-per-particle ratios of as-developed nanoparticle-drug conjugates were established and used to obtain favorable pharmacokinetic profiles. The in vivo efficacy results showed significantly improved biological, therapeutic, and toxicological properties over the native drug after intravenous administration in platelet-derived growth factor-driven genetically engineered mouse model, and an epidermal growth factor expressing patient-derived xenograft (EGFR PDX) model. Conclusions: Ultrasmall C' dot-drug conjugates showed great translational potential over doxorubicin for improving the therapeutic outcome of patients with high-grade gliomas, even without a cancer-targeting moiety.

In Vivo Murine Models of Cardiotoxicity Due to Anticancer Drugs: Challenges and Opportunities for Clinical Translation

Modern therapeutic approaches have led to an improvement in the chances of surviving a diagnosis of cancer. However, this may come with side effects, with patients experiencing adverse cardiovascular events or exacerbation of underlying cardiovascular disease related to their cancer treatment. Rodent models of chemotherapy-induced cardiotoxicity are useful to define pathophysiological mechanisms of cardiac damage and to identify potential therapeutic targets. The key mechanisms involved in cardiotoxicity induced by specific different antineoplastic agents are summarized in this state-of-the-art review, as well as the rodent models of cardiotoxicity by different classes of anticancer drugs, along with the strategies tested for primary and secondary cardioprotection. Current approaches for early detection of cardiotoxicity in preclinical studies with a focus on the application of advanced imaging modalities and biomarker strategies are also discussed. Potential applications of cardiotoxicity modelling in rodents are illustrated in relation to the advancements of promising research topics of cardiotoxicity. Created with BioRender.com.

Long non-coding RNAs and microRNAs as crucial regulators in cardio-oncology

Cancer is one of the leading causes of morbidity and mortality worldwide. Significant improvements in the modern era of anticancer therapeutic strategies have increased the survival rate of cancer patients. Unfortunately, cancer survivors have an increased risk of cardiovascular diseases, which is believed to result from anticancer therapies. The emergence of cardiovascular diseases among cancer survivors has served as the basis for establishing a novel field termed cardio-oncology. Cardio-oncology primarily focuses on investigating the underlying molecular mechanisms by which anticancer treatments lead to cardiovascular dysfunction and the development of novel cardioprotective strategies to counteract cardiotoxic effects of cancer therapies. Advances in genome biology have revealed that most of the genome is transcribed into non-coding RNAs (ncRNAs), which are recognized as being instrumental in cancer, cardiovascular health, and disease. Emerging studies have demonstrated that alterations of these ncRNAs have pathophysiological roles in multiple diseases in humans. As it relates to cardio-oncology, though, there is limited knowledge of the role of ncRNAs. In the present review, we summarize the up-to-date knowledge regarding the roles of long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) in cancer therapy-induced cardiotoxicities. Moreover, we also discuss prospective therapeutic strategies and the translational relevance of these ncRNAs.

Advanced Imaging and New Cardiac Biomarkers in Long-term Follow-up After Childhood Cancer

OBJECTIVES

Pathologic ejection fraction (EF), shortening fraction (FS), and standard heart failure biomarkers (high sensitive troponin T and N-terminal brain natriuretic peptide) during follow-up after childhood cancer have been associated with irreversible cardiac damage. We aimed to evaluate strain imaging values by echocardiography and new biomarkers for heart failure with preserved ejection fraction (HFpEF) as potential more sensitive parameters for cardiac deterioration in childhood cancer survivors (CCS).

MATERIALS AND METHODS

Prospective study with 50 CCS (median 16.2 y) at a median follow-up of 13 years. In addition to standard echo and laboratory parameters for heart failure, strain measurements and new biomarkers, including myocardial inflammation (interleukin 6), extracellular matrix (ECM) remodeling (C-telopeptide for type I collagen, intact N-terminal propeptide of type III procollagen), and other heart failure biomarkers (galectin 3, solutable ST2, growth differentiation factor 15), were obtained and compared with 50 healthy controls.

RESULTS

No significant differences in EF, FS, high sensitive troponin T, N-terminal brain natriuretic peptide, interleukin 6, solutable ST2, and galectin 3 were found between study and control groups. In contrast, strain imaging showed significant differences between both groups (global longitudinal strainGLS -16.1% vs. -20.4%, P<0.0001; global circumferential strain -14.3 vs. -21.4%, P<0.0001), detecting 66% (global longitudinal strain) and 76% (global circumferential strain) of patients with pathologic values in contrast to 6% (EF) and 16% (FS) for standard parameters. Markers for disturbances of ECM remodeling (C-telopeptide for type I collagen, intact N-terminal propeptide of type III procollagen, each P<0.0001) and growth differentiation factor 15 (P<0.0001) were significantly different between the groups.

CONCLUSION

Strain imaging and new cardiac biomarkers used in HFpEF focusing on ECM remodeling appear to be more sensitive in detecting early remodeling processes in CCS than standard echo and laboratory parameters.

MicroRNA-34a-5p as a promising early circulating preclinical biomarker of doxorubicin-induced chronic cardiotoxicity

Cardiotoxicity is a serious adverse effect of an anticancer drug, doxorubicin (DOX), which can occur within a year or decades after completion of therapy. The present study was designed to address a knowledge gap concerning a lack of circulating biomarkers capable of predicting the risk of cardiotoxicity induced by DOX. Profiling of 2083 microRNAs (miRNAs) in mouse plasma revealed 81 differentially expressed miRNAs one week after 6, 9, 12, 18, or 24 mg/kg total cumulative DOX doses (early-onset model) or saline (SAL). Among these, the expression of 7 miRNAs were altered prior to the onset of myocardial injury at 12 mg/kg and higher cumulative doses. The expression of only miR-34a-5p was significantly (FDR<0.1) elevated at all total cumulative doses compared to concurrent SAL-treated controls and showed a statistically significant dose-related response. The trend in plasma miR-34a-5p expression levels during DOX exposures also correlated with a significant dose-related increase in cardiac expression of miR-34a-5p in these mice. Administration of a cardioprotective drug, dexrazoxane, to mice before DOX treatment, significantly mitigated miR-34a-5p expression in both plasma and heart in conjunction with attenuation of cardiac pathology. This association between plasma and heart may suggest miR-34a-5p as a potential early circulating marker of early-onset DOX cardiotoxicity. In addition, higher expression of miR-34a-5p (FDR<0.1) in plasma and heart compared to SAL-treated controls 24 weeks after 24 mg/kg total cumulative DOX dose, when cardiac function was altered in our recently established delayed-onset cardiotoxicity model, indicated its potential as an early biomarker of delayed-onset cardiotoxicity.

Weighted gene co-expression network-based approach to identify key genes associated with anthracycline-induced cardiotoxicity and construction of miRNA-transcription factor-gene regulatory network

BACKGROUND

Cardiotoxicity is a common complication following anthracycline chemotherapy and represents one of the serious adverse reactions affecting life, which severely limits the effective use of anthracyclines in cancer therapy. Although some genes have been investigated by individual studies, the comprehensive analysis of key genes and molecular regulatory network in anthracyclines-induced cardiotoxicity (AIC) is lacking but urgently needed.

METHODS

The present study integrating several transcription profiling datasets aimed to identify key genes associated with AIC by weighted correlation network analysis (WGCNA) and differentially expressed analysis (DEA) and also constructed miRNA-transcription factor-gene regulatory network. A total of three transcription profiling datasets involving 47 samples comprising 41 rat heart tissues and 6 human induced pluripotent stem cell-derived cardiomyocytes (hiPSCMs) samples were enrolled.

RESULTS

The WGCNA and DEA with E-MTAB-1168 identified 14 common genes affected by doxorubicin administrated by 4 weeks or 6 weeks. Functional and signal enrichment analyses revealed that these genes were mainly enriched in the regulation of heart contraction, muscle contraction, heart process, and oxytocin signaling pathway. Ten (Ryr2, Casq1, Fcgr2b, Postn, Tceal5, Ccn2, Tnfrsf12a, Mybpc2, Ankrd23, Scn3b) of the 14 genes were verified by another gene expression profile GSE154603. Importantly, three key genes (Ryr2, Tnfrsf12a, Scn3b) were further validated in a hiPSCMs-based in-vitro model. Additionally, the miRNA-transcription factor-gene regulatory revealed several top-ranked transcription factors including Tcf12, Ctcf, Spdef, Ebf1, Sp1, Rcor1 and miRNAs including miR-124-3p, miR-195-5p, miR-146a-5p, miR-17-5p, miR-15b-5p, miR-424-5p which may be involved in the regulation of genes associated with AIC.

CONCLUSIONS

Collectively, the current study suggested the important role of the key genes, oxytocin signaling pathway, and the miRNA-transcription factor-gene regulatory network in elucidating the molecular mechanism of AIC.

The Protective Effects of Coenzyme Q10 and Lisinopril Against Doxorubicin-Induced Cardiotoxicity in Rats: A Stereological and Electrocardiogram Study

Doxorubicin (DOX) is used as an anticancer drug despite its several side effects, especially its irreversible impacts on cardiotoxicity. Coenzyme Q10 (Q10) as a powerful antioxidant and lisinopril (LIS) as an angiotensin-converting enzyme inhibitor seem to provide protection against DOX-induced cardiotoxicity. Therefore, this study aimed to assess the cardioprotective effects of Q10 and LIS against DOX-induced cardiotoxicity in rats. Adult male Sprague-Dawley rats were randomly assigned into the control, LIS, Q10, DOX, DOX + LIS, and DOX + Q10 groups. On day 21, ECG was recorded and the right ventricle was dissected for evaluation of catalase activity and malondialdehyde (MDA) concentration. Additionally, the left ventricle and the sinoatrial (SA) node were dissected to assess the stereological parameters. The results of ECG indicated bradycardia and increase in QRS duration and QT interval in the DOX group compared to the control group. Meanwhile, the total volumes of the left ventricle, myocytes, and microvessels and the number of cardiomyocyte nuclei decreased, whereas the total volume of the connective tissue and the mean volume of cardiomyocytes increased in the DOX group. On the other hand, the SA node and the connective tissue were enlarged, while the volume of the SA node nuclei was reduced in the DOX group. Besides, catalase activity was lower and MDA concentration was higher in the DOX-treated group. Q10 could recover most stereological parameters, catalase activity, and MDA concentration. LIS also prevented some stereological parameters and ECG changes and improved catalase activity and MDA concentration in the DOX group. The findings suggested that Q10 and LIS exerted cardioprotective effects against DOX-induced cardiac toxicity.

Doxorubicin-induced delayed-onset subclinical cardiotoxicity in mice

Subclinical cardiotoxicity at low total cumulative doxorubicin (DOX) doses can manifest into cardiomyopathy in long-term cancer survivors. However, the underlying mechanisms are poorly understood. In male B6C3F₁ mice, assessment of cardiac function by echocardiography was performed at 1, 4, 10, 17, and 24 weeks after exposure to 6, 9, 12, and 24 mg/kg total cumulative DOX doses or saline (SAL) to monitor development of delayed-onset cardiotoxicity. The 6- or 9-mg/kg total cumulative doses resulted in a significant time-dependent decline in systolic function (left ventricular ejection fraction (LVEF) and fractional shortening (FS)) during the 24-week recovery although there was not a significant alteration in % LVEF or % FS at any specific time point during the recovery. A significant decline in systolic function was elicited by the cardiotoxic cumulative DOX dose (24 mg/kg) during the 4- to 24-week period after treatment compared to SAL-treated counterparts. At 24 weeks after DOX treatment, a significant dose-related decrease in the expression of genes and proteins involved in sarcoplasmic reticulum (SR) calcium homeostasis (Ryr2 and Serca2) was associated with a dose-related increase in the transcript level of Casp12 (SR-specific apoptosis) in hearts. These mice also showed enhanced apoptotic activity in hearts indicated by a significant dose-related elevation in the number of apoptotic cardiomyocytes compared to SAL-treated counterparts. These findings collectively suggest that a steady decline in SR calcium handling and apoptosis might be involved in the development of subclinical cardiotoxicity that can evolve into irreversible cardiomyopathy later in life.

Genetic basis of anthracyclines cardiotoxicity: Literature review

The purpose of this review was to systematize data on molecular genetic markers of increased risk of cardiotoxic effects, as well as to search for risk and protective variants of candidate genes. Today, the therapy of malignant neoplasms is based on the use of anthracyclines – drugs of the cytostatic mechanism of action. Along with their effectiveness, these drugs can have a cardiotoxic effect on cardiomyocytes by increasing the amount of reactive oxygen species and disrupting mitochondrial biogenesis. Pathological disorders lead to an increased risk of myocardial dysfunction and a number of other cardiovascular pathologies in patients receiving chemotherapy using anthracyclines. The cardiotoxic effect of anthracyclines leads to cardiomyopathy, heart failure, myocardial infarction, and thrombosis. Early detection of cardiotoxic damage leads to reducing the negative effects of these drugs due to changes in chemotherapy tactics. It is known that the risk of cardiotoxic myocardial damage is genetically determined and controlled by more than 80 genes. In this review, the description of basic molecules such as ATP-binding cassette transporters and solute carrier family (SLC transporters), carbonyl reductase, molecules of antioxidant defense, xenobiotic and iron metabolism was performed. In addition, a special attention is paid to the study of epigenetic and post-translational regulation. The available data are characterized by some inconsistency that may be explained by the ethnic differences of the studied populations. Thus, a more detailed research of various ethnic groups, gene-gene interactions between potential candidate genes and epigenetic regulation is necessary. Thus, understanding the contribution of genetic polymorphism to the development of cardiotoxicity will help to assess the individual risks of cardiovascular pathology in patients with various types of cancer, as well as reduce the risk of myocardial damage by developing individual preventive measures and correcting chemotherapy.

Adjuvant breast cancer treatments cardiotoxicity and modern methods of detection and prevention of cardiac complications

The most common cancer diagnosis in female population is breast cancer, which affects every year about 2.0 million women worldwide. In recent years, significant progress has been made in oncological therapy, in systemic treatment, and in radiotherapy of breast cancer. Unfortunately, the improvement in the effectiveness of oncological treatment and prolonging patients' life span is associated with more frequent occurrence of organ complications, which are side effects of this treatment. Current recommendations suggest a periodic monitoring of the cardiovascular system in course of oncological treatment. The monitoring includes the assessment of occurrence of risk factors for cardiovascular diseases in combination with the evaluation of the left ventricular systolic function using echocardiography and electrocardiography as well as with the analysis of the concentration of cardiac biomarkers. The aim of this review was critical assessment of the breast cancer therapy cardiotoxicity and the analysis of methods its detections. The new cardio-specific biomarkers in serum, the development of modern imaging techniques (Global Longitudinal Strain and Three-Dimensional Left Ventricular Ejection Fraction) and genotyping, and especially their combined use, may become a useful tool for identifying patients at risk of developing cardiotoxicity, who require further cardiovascular monitoring or cardioprotective therapy.

MicroRNA miR-215-5p regulates doxorubicin-induced cardiomyocyte injury by targeting ZEB2

ABSTRACT

Doxorubicin (DOX) is a chemotherapeutic drug for treating various cancers. However, the DOX-induced cardiotoxicity greatly limits its clinical application. MicroRNAs (miRNAs) are emerged as critical mediators of cardiomyocyte injury. This work explored the function of miR-215-5p in the regulation of DOX-induced mouse HL-1 cardiomyocyte injury. An in vitro model of DOX-treated cardiotoxicity was established in HL-1 cells. Gene expression was measured by RT-qPCR. Cell viability was detected using CCK-8. Cell death and apoptosis were tested using TUNEL, flow cytometry, and caspase 3/7 activity assays. Luciferase reporter assay was used to examine the target of miR-215-5p. We found that DOX induced cardiomyocyte injury and upregulated miR-215-5p in HL-1 cells. Inhibition of miR-215-5p attenuated DOX-induced cardiomyocyte death and apoptosis in vitro. Mechanistical experiments indicated that ZEB2 was targeted by miR-215-5p. Additionally, ZEB2 expression was reduced in DOX-treated HL-1 cells. Rescue assays indicated that ZEB2 knockdown reversed the effects of miR-215-5p inhibition. In conclusion, miR-215-5p inhibition protects HL-1 cells against DOX-induced injury by upregulating ZEB2 expression.

MicroRNA expression profiling involved in doxorubicin-induced cardiotoxicity using high-throughput deep-sequencing analysis

MicroRNAs (miRNAs/miRs) are sensitive biomarkers and endogenous repressors of gene expression by decreasing mRNA stability and interfering with mRNA translation. Despite a number of investigations revealing the dysregulation of miRNA expression associated with cardiotoxicity induced by doxorubicin (Dox), perturbation of miRNAs directly resulting from Dox at early stage in cardiomyocytes and the target gene interaction remain largely unknown. In the present study, high-throughput deep-sequencing was used to analyze changes in global miRNA expression in H9c2 cardiomyocytes exposed to 5 µg/ml Dox for 0, 12 or 24 h. Compared with the 0-h time point, the expression levels of 386 unique miRNAs were altered. Based on miRNA expression and fold-change, the target genes of 76 selected miRNAs were further analyzed using gene interaction networks and pathway enrichment analysis. These miRNAs were involved in the regulation of different pathways, whose functions included apoptosis, cell proliferation, extracellular matrix remodeling, oxidative stress and lipid metabolism. These differentially expressed miRNAs included let-7 family, miR-29b-3p, miR-378-3/5p, miR-351-3p, miR-664-3p, miR-455-3p, miR-298-3p, miR-702-5p, miR-128-1-5p, miR-671 and miR-421-5p. The present data indicated that global wide miRNA profiling in Dox-induced cardiomyocytes may provide a novel mechanistic insight into understanding Dox-induced heart failure and cardiotoxicity, as well as novel biomarkers and therapeutic targets.

PEG-polyaminoacid based micelles for controlled release of doxorubicin: Rational design, safety and efficacy study

A library of amphiphilic monomethoxypolyethylene glycol (mPEG) terminating polyaminoacid co-polymers able to self-assemble into colloidal systems was screened for the delivery and controlled release of doxorubicin (Doxo). mPEG-Glu/Leu random co-polymers were generated by Ring Opening Polymerization from 5 kDa mPEG-NH₂ macroinitiator using 16:0:1, 8:8:1, 6:10:1, 4:12:1 γ-benzyl glutamic acid carboxy anhydride monomer/leucine N-carboxy anhydride monomer/PEG molar ratios. Glutamic acid was selected for chemical conjugation of Doxo, while leucine units were introduced in the composition of the polyaminoacid block as spacer between adjacent glutamic repeating units to minimize the steric hindrance that could impede the Doxo conjugation and to promote the polymer self-assembly by virtue of the aminoacid hydrophobicity. The benzyl ester protecting the γ-carboxyl group of glutamic acid was quantitatively displaced with hydrazine to yield mPEG_5kDa-b-(hydGlu_m-r-Leu_n). Doxo was conjugated to the diblock co-polymers through pH-sensitive hydrazone bond. The Doxo derivatized co-polymers obtained with a 16:0:1, 8:8:1, 6:10:1 Glu/Leu/PEG ratios self-assembled into 30-40 nm spherical nanoparticles with neutral zeta-potential and CMC in the range of 4-7 μM. At pH 5.5, mimicking endosome environment, the carriers containing leucine showed a faster Doxo release than at pH 7.4, mimicking the blood conditions. Doxo-loaded colloidal formulations showed a dose dependent cytotoxicity on two cancer cell lines, CT26 murine colorectal carcinoma and 4T1 murine mammary carcinoma with IC₅₀ slightly higher than those of free Doxo. The carrier assembled with the polymer containing 6:10:1 hydGlu/Leu/PEG molar ratio {mPEG_5kDa-b-[(Doxo-hydGlu)₆-r-Leu₁₀]} was selected for subsequent in vitro and in vivo investigations. Confocal imaging on CT26 cell line showed that intracellular fate of the carrier involves a lysosomal trafficking pathway. The intratumor or intravenous injection to CT26 and 4T1 subcutaneous tumor bearing mice yielded higher antitumor activity compared to free Doxo. Furthermore, mPEG_5kDa-b-[(Doxo-hydGlu)₆-r-Leu₁₀] displayed a better safety profile when compared to commercially available Caelyx®.

The Impact of microRNAs in Renin-Angiotensin-System-Induced Cardiac Remodelling

Current knowledge on the renin-angiotensin system (RAS) indicates its central role in the pathogenesis of cardiovascular remodelling via both hemodynamic alterations and direct growth and the proliferation effects of angiotensin II or aldosterone resulting in the hypertrophy of cardiomyocytes, the proliferation of fibroblasts, and inflammatory immune cell activation. The noncoding regulatory microRNAs has recently emerged as a completely novel approach to the study of the RAS. A growing number of microRNAs serve as mediators and/or regulators of RAS-induced cardiac remodelling by directly targeting RAS enzymes, receptors, signalling molecules, or inhibitors of signalling pathways. Specifically, microRNAs that directly modulate pro-hypertrophic, pro-fibrotic and pro-inflammatory signalling initiated by angiotensin II receptor type 1 (AT1R) stimulation are of particular relevance in mediating the cardiovascular effects of the RAS. The aim of this review is to summarize the current knowledge in the field that is still in the early stage of preclinical investigation with occasionally conflicting reports. Understanding the big picture of microRNAs not only aids in the improved understanding of cardiac response to injury but also leads to better therapeutic strategies utilizing microRNAs as biomarkers, therapeutic agents and pharmacological targets.

Noncoding RNAs in doxorubicin-induced cardiotoxicity and their potential as biomarkers and therapeutic targets

Anthracyclines, such as doxorubicin (DOX), are well known for their high efficacy in treating multiple cancers, but their clinical usage is limited due to their potential to induce fatal cardiotoxicity. Such detrimental effects significantly impact the overall physical condition or even induce the morbidity and mortality of cancer survivors. Therefore, it is extremely important to understand the mechanisms of DOX-induced cardiotoxicity to develop methods for the early detection of cytotoxicity and therapeutic applications. Studies have shown that many molecular events are involved in DOX-induced cardiotoxicity. However, the precise mechanisms are still not completely understood. Recently, noncoding RNAs (ncRNAs) have been extensively studied in a diverse range of regulatory roles in cellular physiological and pathological processes. With respect to their roles in DOX-induced cardiotoxicity, microRNAs (miRNAs) are the most widely studied, and studies have focused on the regulatory roles of long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs), which have been shown to have significant functions in the cardiovascular system. Recent discoveries on the roles of ncRNAs in DOX-induced cardiotoxicity have prompted extensive interest in exploring candidate ncRNAs for utilization as potential therapeutic targets and/or diagnostic biomarkers. This review presents the frontier studies on the roles of ncRNAs in DOX-induced cardiotoxicity, addresses the possibility and prospects of using ncRNAs as diagnostic biomarkers or therapeutic targets, and discusses the possible reasons for related discrepancies and limitations of their use.

Rational Design of DNA Framework-Based Hybrid Nanomaterials for Anticancer Drug Delivery

Engineered DNA frameworks have been extensively exploited as affinity scaffolds for drug delivery. However, few studies focus on the rational design to comprehensively improve their stability, internalization kinetics, and drug loading efficiency. Herein, DNA framework-based hybrid nanomaterials are rationally engineered by using a molecular docking tool, where the framework acts as a template to support conjugated polymers. The hybrid materials exhibit high stability in biofluids owning to the multiple interactions between DNA and cationic conjugated polymer. Through molecular docking, it is found that a specific structure of the conjugated polymer at major grooves of DNA gives rise to a unique pocket for small-molecular drug doxorubicin (DOX) yielding lower binding energy than conventional DOX binding sites. This increases the binding affinity of DOX, allowing for high drug loading content and efficiency, and preventing drug leakage under physiological condition. As a proof of concept, the hybrid nanomaterials equipped with aptamer are used to carry DOX and antisense oligonucleotide G3139, which effectively inhibits solid tumor growth and shows negligible side effects on mice. It is anticipated that this approach would find broad applications in hybrid materials design and precise medicine.

Epigenetic Changes Associated With Anthracycline-Induced Cardiotoxicity

Advances in cancer treatment have significantly improved the survival of patients with cancer, but, unfortunately, many of these treatments also have long‐term complications. Cancer treatment‐related cardiotoxicities are becoming a significant clinical problem that a new discipline, Cardio‐Oncology, was established to advance the cardiovascular care of patients with growing cancer populations. Anthracyclines are a class of chemotherapeutic agents used to treat many cancers in adults and children. Their clinical use is limited by anthracycline‐induced cardiotoxicity (AIC), which can lead to heart failure. Early‐onset cardiotoxicity appears within a year of treatment, whereas late‐onset cardiotoxicity occurs > 1 year and even up to decades after treatment completion. The pathophysiology of AIC was hypothesized to be caused by generation of reactive oxygen species that lead to lipid peroxidation, defective mitochondrial biogenesis, and DNA damage of the cardiomyocytes. The accumulation of anthracycline metabolites was also proposed to cause mitochondrial damage and the induction of cardiac cell apoptosis, which induces arrhythmias, contractile dysfunction, and cardiomyocyte death. This paper will provide a general overview of cardiotoxicity focusing on the effect of anthracyclines and their epigenetic molecular mechanisms on cardiotoxicity.

The Role of Biomarkers to Evaluate Cardiotoxicity

OPINION STATEMENT

Moderate-level evidence suggests that cardiac troponin and natriuretic peptides are useful for risk stratification and early identification of anthracycline cardiotoxicity; however, many of these studies used older chemotherapy regimens, and thus, the applicability to current anthracycline treatment regimens is uncertain. Further research is needed to determine optimal timing and thresholds for troponin and natriuretic peptides in anthracycline-treated patients and evaluate these and other promising biomarkers for anti-HER2 therapies, thoracic radiation, anti-VEGF therapy, and fluoropyrimidine therapy-related cardiotoxicity. Risk tools that combine cardiac risk factors, cancer treatment variables, biomarkers, and imaging parameters are most likely to accurately identify individuals at highest risk for cancer therapy cardiotoxicity. Clinical trials focusing cardioprotective strategies on high-risk individuals are more likely to result in clinically significant results compared with primary prevention cardioprotective approaches.

Cardioprotective effects of miR-34a silencing in a rat model of doxorubicin toxicity

Cardiotoxicity remains a serious problem in anthracycline-treated oncologic patients. Therapeutic modulation of microRNA expression is emerging as a cardioprotective approach in several cardiovascular pathologies. MiR-34a increased in animals and patients exposed to anthracyclines and is involved in cardiac repair. In our previous study, we demonstrated beneficial effects of miR-34a silencing in rat cardiac cells exposed to doxorubicin (DOXO). The aim of the present work is to evaluate the potential cardioprotective properties of a specific antimiR-34a (Ant34a) in an experimental model of DOXO-induced cardiotoxicity. Results indicate that in our model systemic administration of Ant34a completely silences miR-34a myocardial expression and importantly attenuates DOXO-induced cardiac dysfunction. Ant34a systemic delivery in DOXO-treated rats triggers an upregulation of prosurvival miR-34a targets Bcl-2 and SIRT1 that mediate a reduction of DOXO-induced cardiac damage represented by myocardial apoptosis, senescence, fibrosis and inflammation. These findings suggest that miR-34a therapeutic inhibition may have clinical relevance to attenuate DOXO-induced toxicity in the heart of oncologic patients.

NF-κB pathway activation during endothelial-to-mesenchymal transition in a rat model of doxorubicin-induced cardiotoxicity

Doxorubicin is a commonly used anthracycline chemotherapeutic agent; however, its application is limited owing to its cardiotoxicity. Current clinical treatments cannot efficiently or fully prevent doxorubicin-induced toxicity, primarily because its pathogenesis and mechanisms of action remain unknown. In this study, we established a rat model of chronic doxorubicin-induced cardiotoxicity, in which the severity of cardiac fibrosis and hydroxyproline levels increased in a time-dependent manner. Doxorubicin damaged the mitochondria and blood vessels and induced autophagy. Cells undergoing endothelial-to-mesenchymal transition (EndoMT)and those expressing endothelial cell and myofibroblast markers were simultaneously observed in vitro and in rats treated with doxorubicin. The NF-κB pathway was activated during EndoMT, andp65 and p-p65 were strongly expressed in the nucleus of endothelial cells in vitro. Taken together, these results suggest that vascular injury and cardiac fibrosis are characteristic symptoms of doxorubicin-induced cardiotoxicity. The NF-κB pathway-associated EndoMT may influence the pathogenesis of doxorubicin-induced cardiotoxicity, and the constituents of this pathway may be potential therapeutic targets to prevent the development of this condition.

Cardiac dysfunction in cancer patients: beyond direct cardiomyocyte damage of anticancer drugs: novel cardio-oncology insights from the joint 2019 meeting of the ESC Working Groups of Myocardial Function and Cellular Biology of the Heart

In western countries, cardiovascular (CV) disease and cancer are the leading causes of death in the ageing population. Recent epidemiological data suggest that cancer is more frequent in patients with prevalent or incident CV disease, in particular, heart failure (HF). Indeed, there is a tight link in terms of shared risk factors and mechanisms between HF and cancer. HF induced by anticancer therapies has been extensively studied, primarily focusing on the toxic effects that anti-tumour treatments exert on cardiomyocytes. In this Cardio-Oncology update, members of the ESC Working Groups of Myocardial Function and Cellular Biology of the Heart discuss novel evidence interconnecting cardiac dysfunction and cancer via pathways in which cardiomyocytes may be involved but are not central. In particular, the multiple roles of cardiac stromal cells (endothelial cells and fibroblasts) and inflammatory cells are highlighted. Also, the gut microbiota is depicted as a new player at the crossroads between HF and cancer. Finally, the role of non-coding RNAs in Cardio-Oncology is also addressed. All these insights are expected to fuel additional research efforts in the field of Cardio-Oncology.

Long-Term Exercise Alters the Profiles of Circulating Micro-RNAs in the Plasma of Young Women

Objective: The objective of this paper was to study the effects of long-term exercise on circulating microRNAs (miRNAs) in human plasma.

Methods: Whole blood was collected from 10 female elite athletes with at least 5 years of training experience in a Synchronized Swimming Group (S group) and 15 female college students without regular exercise training (C group). Plasma miRNAs were then isolated, sequenced, and semi-quantified by the second-generation sequencing technology, and the results were analyzed by bioinformatics methods.

Results: We found 380 differentially expressed miRNAs in the S group compared with the C group, among which 238 miRNAs were upregulated and 142 were downregulated. The top five abundant miRNAs in the 380 miRNAs of the S group are hsa-miR-451a, hsa-miR-486, hsa-miR-21-5p, hsa-miR-423-5p, and hsa-let-7b-5p. Muscle-specific/enriched miRNAs were not significantly different, except for miR-206 and miR-486. According to the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, a large proportion of the differentially expressed miRNAs are targeted in cancer-related pathways, including proteoglycans in cancer and miRNAs in cancer and basal cell carcinoma. As the levels of circulating miRNAs (ci-miRNAs) are commonly known to be significantly deregulated in cancer patients, we further compared the levels of some well-studied miRNAs in different types of cancer patients with those in the S group and found that long-term exercise regulates the level of ci-miRNAs in an opposite direction to those in cancer patients.

Conclusion: Long-term exercise significantly alters the profiles of plasma miRNAs in healthy young women. It may reduce the risk of certain types of cancers by regulating plasma miRNA levels.

Comprehensive analysis of cardiac function, blood biomarkers and histopathology for milrinone-induced cardiotoxicity in cynomolgus monkeys

The objective of this study was to elucidate the underlying cardiotoxic mechanism of milrinone, a cAMP phosphodiesterase 3 inhibitor, by evaluating cardiac functions, blood biomarkers including cardiac troponin I (cTnI), microRNAs (miR-1, miR-133a and miR-499a) and various endogenous metabolites, and histopathology in conscious cynomolgus monkeys. Milrinone at doses of 0, 3 and 30 mg/kg were orally administered to monkeys (n = 3-4/group), and the endpoints were evaluated 1 to 24 h post-dosing. Milrinone caused myocardial injuries characterized by myocardial degeneration/necrosis, cell infiltration and hemorrhage 24 h after drug administration. Cardiac functional analysis revealed that milrinone dose-dependently increased the maximum upstroke velocity of the left ventricular pressure and heart rate, and decreased the QA interval and systemic blood pressure 1-4 h post-dosing, being associated with pharmacological action of the drug. In the blood biomarker analysis, only plasma cTnI was dose-dependently increased 4-7 h after drug administration, suggesting that cTnI is the most sensitive biomarker for early detection of milrinone-induced myocardial injuries. In the metabolomics analysis, high dose of milrinone induced transient changes in lipid metabolism, amino acid utilization and oxidative stress, together with the pharmacological action of increased cAMP and lipolysis 1 h post-dosing before the myocardial injuries were manifested by increased cTnI levels. Taken together, milrinone showed acute positive inotropic and multiple metabolic changes including excessive pharmacological actions, resulting in myocardial injuries. Furthermore, a comprehensive analysis of cardiac functions, blood biomarkers and histopathology can provide more appropriate information for overall assessment of preclinical cardiovascular safety.

MicroRNAs in Cancer Treatment-Induced Cardiotoxicity

Cancer treatment has made significant progress in the cure of different types of tumors. Nevertheless, its clinical use is limited by unwanted cardiotoxicity. Aside from the conventional chemotherapy approaches, even the most newly developed, i.e., molecularly targeted therapy and immunotherapy, exhibit a similar frequency and severity of toxicities that range from subclinical ventricular dysfunction to severe cardiomyopathy and, ultimately, congestive heart failure. Specific mechanisms leading to cardiotoxicity still remain to be elucidated. For instance, oxidative stress and DNA damage are considered key players in mediating cardiotoxicity in different treatments. microRNAs (miRNAs) act as key regulators in cell proliferation, cell death, apoptosis, and cell differentiation. Their dysregulation has been associated with adverse cardiac remodeling and toxicity. This review provides an overview of the cardiotoxicity induced by different oncologic treatments and potential miRNAs involved in this effect that could be used as possible therapeutic targets.

Potential Clinical Implications of miR-1 and miR-21 in Heart Disease and Cardioprotection

The interest in non-coding RNAs, which started more than a decade ago, has still not weakened. A wealth of experimental and clinical studies has suggested the potential of non-coding RNAs, especially the short-sized microRNAs (miRs), to be used as the new generation of therapeutic targets and biomarkers of cardiovascular disease, an ever-growing public health issue in the modern world. Among the hundreds of miRs characterized so far, microRNA-1 (miR-1) and microRNA-21 (miR-21) have received some attention and have been associated with cardiac injury and cardioprotection. In this review article, we summarize the current knowledge of the function of these two miRs in the heart, their association with cardiac injury, and their potential cardioprotective roles and biomarker value. While this field has already been extensively studied, much remains to be done before research findings can be translated into clinical application for patient’s benefit.

Doxorubicin-Induced Cardiotoxicity in Collaborative Cross (CC) Mice Recapitulates Individual Cardiotoxicity in Humans

Anthracyclines cause progressive cardiotoxicity whose ultimate severity is individual to the patient. Genetic determinants contributing to this variation are difficult to study using current mouse models. Our objective was to determine whether a spectrum of anthracycline induced cardiac disease can be elicited across 10 Collaborative Cross mouse strains given the same dose of doxorubicin. Mice from ten distinct strains were given 5 mg/kg of doxorubicin intravenously once weekly for 5 weeks (total 25 mg/kg). Mice were killed at acute or chronic timepoints. Body weight was assessed weekly, followed by terminal complete blood count, pathology and a panel of biomarkers. Linear models were fit to assess effects of treatment, sex, and sex-by-treatment interactions for each timepoint. Impaired growth and cardiac pathology occurred across all strains. Severity of these varied by strain and sex, with greater severity in males. Cardiac troponin I and myosin light chain 3 demonstrated strain- and sex-specific elevations in the acute phase with subsequent decline despite ongoing progression of cardiac disease. Acute phase cardiac troponin I levels predicted the ultimate severity of cardiac pathology poorly, whereas myosin light chain 3 levels predicted the extent of chronic cardiac injury in males. Strain- and sex-dependent renal toxicity was evident. Regenerative anemia manifested during the acute period. We confirm that variable susceptibility to doxorubicin-induced cardiotoxicity observed in humans can be modeled in a panel of CC strains. In addition, we identified a potential predictive biomarker in males. CC strains provide reproducible models to explore mechanisms contributing to individual susceptibility in humans.

Exercise-induced cardiac opioid system activation attenuates apoptosis pathway in obese rats

AIM

To compare the effect of 150 min vs. 300 min of weekly moderate intensity exercise training on the activation of the opioid system and apoptosis in the hearts of a diet-induced obesity model.

METHODS

Male Wistar rats were fed with either control (CON) or high fat (HF) diet for 32 weeks. At the 20th week, HF group was subdivided into sedentary, low (LEV, 150 min·week^-1) or high (HEV, 300 min·week^-1) exercise volume. After 12 weeks of exercise, body mass gain, adiposity index, systolic blood pressure, cardiac morphometry, apoptosis biomarkers and opioid system expression were evaluated.

RESULTS

Sedentary animals fed with HF presented pathological cardiac hypertrophy and higher body mass gain, systolic blood pressure and adiposity index than control group. Both exercise volumes induced physiological cardiac hypertrophy, restored systolic blood pressure and improved adiposity index, but only 300 min·week^-1 reduced body mass gain. HF group exhibited lower proenkephalin, PI3K, ERK and GSK-3β expression, and greater activated caspase-3 expression than control group. Compared to HF, no changes in the cardiac opioid system were observed in the 150 min·week^-1 of exercise training, while 300 min·week^-1 showed greater proenkephalin, DOR, KOR, MOR, Akt, ERK and GSK-3β expression, and lower activated caspase-3 expression.

CONCLUSION

300 min·week^-1 of exercise training triggered opioid system activation and provided greater cardioprotection against obesity than 150 min·week^-1. Our findings provide translational aspect with clinical relevance about the critical dose of exercise training necessary to reduce cardiovascular risk factors caused by obesity.

Imatinib-induced changes in the expression profile of microRNA in the plasma and heart of mice-A comparison with doxorubicin

Cardiotoxicity is a serious adverse reaction to cancer chemotherapy and may lead to critical heart damage. Imatinib mesylate (IMB), a selective tyrosine kinase inhibitor, is sometimes accompanied by severe cardiovascular complications. To minimize risk, early biomarkers of such complications are of utmost importance. At the present time, microRNAs (miRNAs) are intensively studied as potential biomarkers of many pathological processes. Many miRNAs appear to be specific in some tissues, including the heart. In the present study we have explored the potential of specific miRNAs to be early markers of IMB-induced cardiotoxicity. Doxorubicin (DOX), an anthracycline with well-known cardiotoxicity, was used for comparison. NMRI mice were treated with IMB or DOX for nine days in doses corresponding to the highest recommended doses in oncological patients, following which plasmatic levels of miRNAs were analyzed in miRNA microarrays and selected cardio-specific miRNAs were quantified using qPCR. The plasmatic level of miR-1a, miR-133a, miR-133b, miR-339, miR-7058, miR-6236 and miR-6240 were the most different between the IMB-treated and control mice. Interestingly, most of the miRNAs affected by DOX were also affected by IMB showing the same trends. Concerning selected microRNAs in the hearts of individual mice, only miR-34a was significantly increased after DOX treatment, and only miR-205 was significantly decreased after IMB and DOX treatment. However, no changes in any miRNA expression correlated with the level of troponin T, a classical marker of heart injury.

MicroRNA expression, targeting, release dynamics and early-warning biomarkers in acute cardiotoxicity induced by triptolide in rats

Tripterygium wilfordii Hook. F. is a plant used in traditional Chinese medicine to treat rheumatoid arthritis, lupus erythematosus, and psoriasis in China. However, its main active substance, triptolide, has toxic effects on the heart, liver, and kidneys, which limit its clinical application. Therefore, determining the mechanism of cardiotoxicity in triptolide and identifying effective early-warning biomarkers is beneficial for preventing irreversible myocardial injury. We observed changes in microRNAs and aryl hydrocarbon receptor (AhR) as potential biomarkers in triptolide-induced acute cardiotoxicity by using techniques such as polymerase chain reaction (PCR) assay. The results revealed that triptolide increased the heart/body ratio and caused myocardial fiber breakage, cardiomyocyte hypertrophy, increased cell gaps, and nuclear dissolution in treated male rats. Real-time PCR array detection revealed a more than 2-fold increase in the expression of 108 microRNA genes in the hearts of the male rats; this not only regulated the signaling pathways of ErbB, FOXO, AMPK, Hippo, HIF-1α, mTOR, and PI3K-Akt but also participated in biological processes such as cell adhesion, cell cycling, action potential, locomotory behavior, apoptosis, and DNA binding. Moreover, triptolide reduced the circulatory and cardiac levels of AhR protein as a target of these microRNAs and the messenger RNA expression of its downstream gene CYP1 A1. However, decreases in myocardial lactate dehydrogenase, creatine kinase MB, catalase, and glutathione peroxidase activity and an increase in circulating cardiac troponin I were observed only in male rats. Moreover, plasma microRNAs exhibited dynamic change. These results revealed that circulating microRNAs and AhR protein are potentially early-warning biomarkers for triptolide-induced cardiotoxicity.

Role of microRNAs in doxorubicin-induced cardiotoxicity: an overview of preclinical models and cancer patients

Cardiotoxicity is a well-known side effect of doxorubicin (DOX), but the mechanisms leading to this phenomenon are still not completely clear. Prediction of drug-induced dysfunction onset is difficult and is still largely based on detection of cardiac troponin (cTn), a circulating marker of heart damage. In the last years, several investigations focused on the possible involvement of microRNAs (miRNAs) in DOX-induced toxicity in vitro, with contrasting results. Recently, several groups employed animal models to mimic patient’s condition, investigate the biological pathways perturbed by DOX, and identify diagnostic markers of cardiotoxicity. We reviewed the results from several studies investigating cardiac miRNAs expression in rodent models of DOX-treatment. We also discussed the data from two publications indicating the possible use of circulating miRNA as biomarkers of DOX-induced cardiotoxicity. Unfortunately, limited information was derived from these studies, as selection methods of candidate-miRNAs and heterogeneity in cardiotoxicity assessment greatly hampered the novelty and robustness of the findings. Nevertheless, at least one circulating miRNA, miR-1, showed a good potential as early biomarker of drug-mediated cardiac dysfunction onset. The use of animal models to investigate DOX-induced cardiotoxicity surely helps narrowing the gap between basic research and clinical practice. Despite this, several issues, including selection of relevant miRNAs and less-than-optimal assessment of cardiotoxicity, greatly limited the results obtained so far. Nonetheless, the association of patients-based studies with the use of preclinical models may be the key to address the many unanswered questions regarding the pathophysiology and early detection of cardiotoxicity.

Candidate early predictive plasma protein markers of doxorubicin-induced chronic cardiotoxicity in B6C3F1 mice

Cardiotoxicity is a serious adverse effect of doxorubicin (DOX) treatment in cancer patients. Currently, there is a lack of sensitive biomarkers to predict the risk of DOX-induced cardiotoxicity. Using SOMAmer-based proteomic technology, 1129 proteins were profiled to identify potential early biomarkers of cardiotoxicity in plasma from male B6C3F₁ mice given a weekly intravenous dose of 3 mg/kg DOX or saline (SAL) for 2, 3, 4, 6, or 8 weeks (6, 9, 12, 18, or 24 mg/kg cumulative DOX doses, respectively). Also, a group of mice received the cardio-protectant, dexrazoxane (DXZ; 60 mg/kg; intraperitoneal) 30 min before a weekly DOX or SAL dose. Proteomic analysis in plasma collected a week after the last dose showed a significant ≥1.2-fold change in level of 18 proteins in DOX-treated mice compared to SAL-treated counterparts during 8-week exposure. Of these, neurogenic locus notch homolog protein 1 (NOTCH1), von Willebrand factor (vWF), mitochondrial glutamate carrier 2, Wnt inhibitory factor 1, legumain, and mannan-binding lectin serine protease 1 were increased in plasma at 6 mg/kg cumulative DOX dose, prior to the release of myocardial injury marker, cardiac troponin I at 12 mg/kg and higher cumulative doses. These six proteins also remained significantly elevated following myocardial injury or pathology at 24 mg/kg. Pretreatment of mice with DXZ significantly attenuated DOX-induced elevated levels of only NOTCH1 and vWF with mitigation of cardiotoxicity. This suggests NOTCH1 and vWF as candidate early biomarkers of DOX cardiotoxicity, which may help in addressing a clinically important question of identifying cancer patients at risk for cardiotoxicity.

Protecting the heart in cancer therapy

Recent advances in cancer prevention and management have led to an exponential increase of cancer survivors worldwide. Regrettably, cardiovascular disease has risen in the aftermath as one of the most devastating consequences of cancer therapies. In this work, we define cancer therapeutics-induced cardiotoxicity as the direct or indirect cardiovascular injury or injurious effect caused by cancer therapies. We describe four progressive stages of this condition and four corresponding levels of prevention, each having a specific goal, focus, and means of action. We subsequently unfold this didactic framework, surveying mechanisms of cardiotoxicity, risk factors, cardioprotectants, biomarkers, and diagnostic imaging modalities. Finally, we outline the most current evidence-based recommendations in this area according to multidisciplinary expert consensus guidelines.

The role of cardiac biomarkers in cardio-oncology

Major advances in cancer therapy have resulted in an unprecedented improvement in patient survival for many cancers. Partially as a consequence of increased longevity, it has become evident that the cardiovascular system is frequently impacted by chemotherapy, radiation, and particularly certain targeted therapy. Cardiotoxicity continues to be a dose-limiting side effect of many chemotherapeutic agents including the anthracyclines. Early identification of patients at increased risk of cardiotoxicity or detecting cardiac injury at the earliest point will allow for initiation of cardio-protective strategies and hopefully prevent or reduce the need to modify life-saving cancer therapies. Biomarkers offer a potential solution to this clinical challenge because they may assist us in early identification of subclinical cardiac disease. In this review, we will summarize studies conducted evaluating the use of cardiac troponins (TnI, TnT) and natriuretic peptides, BNP and NT-proBNP. Other biomarkers for cardiotoxicity that have been at least preliminarily investigated, including myeloperoxidase and microRNAs, will be discussed as an exploratory tool for evidence of cardiac dysfunction during cancer treatment.

Role of non-coding RNAs in cardiotoxicity of chemotherapy

The long-time paradoxical situation of non-coding RNAs (ncRNAs) has been terminated for they emerge as executive at full spectrum of gene expression and translation. More recently, it has been demonstrated that some ncRNAs apparently are associated with chemotherapy, causing cardiotoxicity, which taint long-term recovery of patients in growing body of evidence. The current review focused on up-to-date knowledge on regulation change and molecular signaling of ncRNAs, at mean time evaluate their potentials as diagnostic biomarkers or therapeutic targets to monitor and protect cardio function.

Effects of Cyclophosphamide and/or Doxorubicin in a Murine Model of Postchemotherapy Cognitive Impairment

Postchemotherapy cognitive impairment, or PCCI, is a common complaint, particularly among breast cancer patients. However, the exact nature of PCCI appears complex. To model the human condition, ovariectomized C57BL/6J mice were treated intravenous weekly for 4 weeks with saline, 2 mg/kg doxorubicin (DOX), 50 mg/kg cyclophosphamide (CYP), or DOX + CYP. For the subsequent 10 weeks, mice were assessed on several behavioral tests, including those measuring spatial learning and memory. After sacrifice, hippocampal spine density and morphology in the dentate gyrus, CA1, and CA3 regions were measured. Additionally, hippocampal levels of total glutathione, glutathione disulfide, MnSOD, CuZnSOD, and cytokines were measured. Body weight decreased in all groups during treatment, but recovered post-treatment. Most behaviors were unaffected by drug treatment: Open field activity, motor coordination, grip strength, water maze and Barnes maze performance, buried food test performance, and novel object and object location recognition tests. There were some significant effects of CYP and DOX + CYP treatment during the initial test of home cage behavior, but these did not persist into the second and third test times. Density of stubby spines, but not mushroom or thin spines, in the dentate gyrus was significantly decreased in the DOX, CYP, and DOX + CYP treatment groups. There were no significant effects in the CA1 or CA3 regions. CuZnSOD levels were significantly increased in DOX + CYP-treated mice; other hippocampal antioxidant levels were unaffected. Most cytokines showed no treatment-related effects, but IL-1β, IL-6, and IL-12 were slightly reduced in mice treated with DOX + CYP. Although the animal model, route of exposure, and DOX and CYP doses used here were reflective of human exposure, there were only sporadic effects due to chemotherapeutic treatment.

Circulating miR-1 as a potential biomarker of doxorubicin-induced cardiotoxicity in breast cancer patients

Cardiotoxicity is associated with the chronic use of doxorubicin leading to cardiomyopathy and heart failure. Identification of cardiotoxicity-specific miRNA biomarkers could provide clinicians with a valuable prognostic tool. The aim of the study was to evaluate circulating levels of miRNAs in breast cancer patients receiving doxorubicin treatment and to correlate with cardiac function. This is an ancillary study from “Carvedilol Effect on Chemotherapy-induced Cardiotoxicity” (CECCY trial), which included 56 female patients (49.9±3.3 years of age) from the placebo arm. Enrolled patients were treated with doxorubicin followed by taxanes. cTnI, LVEF, and miRNAs were measured periodically. Circulating levels of miR-1, -133b, -146a, and -423-5p increased during the treatment whereas miR-208a and -208b were undetectable. cTnI increased from 6.6±0.3 to 46.7±5.5 pg/mL (p<0.001), while overall LVEF tended to decrease from 65.3±0.5 to 63.8±0.9 (p=0.053) over 12 months. Ten patients (17.9%) developed cardiotoxicity showing a decrease in LVEF from 67.2±1.0 to 58.8±2.7 (p=0.005). miR-1 was associated with changes in LVEF (r=-0.531, p<0.001). In a ROC curve analysis miR-1 showed an AUC greater than cTnI to discriminate between patients who did and did not develop cardiotoxicity (AUC = 0.851 and 0.544, p= 0.0016). Our data suggest that circulating miR-1 might be a potential new biomarker of doxorubicin-induced cardiotoxicity in breast cancer patients.

MicroRNA-34a regulates doxorubicin-induced cardiotoxicity in rat

New strategies to prevent and early detect the cardiotoxic effects of the anticancer drug doxorubicin (DOXO) are required. MicroRNAs emerged as potential diagnostic, therapeutic and prognostic approaches in cardiovascular diseases. MiR-34a has a role in cardiac dysfunction and ageing and is involved in several cellular processes associated with DOXO cardiotoxicity. Our in vitro and in vivo results indicated that after DOXO exposure the levels of miR-34a are enhanced in cardiac cells, including Cardiac Progenitor Cells (CPCs). Since one of the determining event responsible for the initiation and evolution of the DOXO toxicity arises at the level of the CPC compartment, we evaluated if miR-34a pharmacological inhibition in these cells ameliorates the detrimental aftermath of the drug. AntimiR-34a has beneficial consequences on vitality, proliferation, apoptosis and senescence of DOXO-treated rat CPC. These effects are mediated by an increase of prosurvival miR-34a targets Bcl-2 and SIRT1, accompanied by a decrease of acetylated-p53 and p16^INK4a. Importantly, miR-34a silencing also reduces the release of this miRNA from DOXO-exposed rCPCs, decreasing its negative paracrine effects on other rat cardiac cells. In conclusion, the silencing of miR-34a could represent a future therapeutic option for cardioprotection in DOXO toxicity and at the same time, it could be considered as a circulating biomarker for anthracycline-induced cardiac damage.

Embryonic stem cell-derived cardiomyocytes for the treatment of doxorubicin-induced cardiomyopathy

BACKGROUND

Doxorubicin (Dox) is a chemotherapy drug with limited application due to cardiotoxicity that may progress to heart failure. This study aims to evaluate the role of cardiomyocytes derived from mouse embryonic stem cells (CM-mESCs) in the treatment of Dox-induced cardiomyopathy (DIC) in mice.

METHODS

The mouse embryonic stem cell (mESC) line E14TG2A was characterized by karyotype analysis, gene expression using RT-PCR and immunofluorescence. Cells were transduced with luciferase 2 and submitted to cardiac differentiation. Total conditioned medium (TCM) from the CM-mESCs was collected for proteomic analysis. To establish DIC in CD1 mice, Dox (7.5 mg/kg) was administered once a week for 3 weeks, resulting in a cumulative Dox dose of 22.5 mg/kg. At the fourth week, a group of animals was injected intramyocardially with CM-mESCs (8 × 10⁵ cells). Cells were tracked by a bioluminescence assay, and the body weight, echocardiogram, electrocardiogram and number of apoptotic cardiomyocytes were evaluated.

RESULTS

mESCs exhibited a normal karyotype and expressed pluripotent markers. Proteomic analysis of TCM showed proteins related to the negative regulation of cell death. CM-mESCs presented ventricular action potential characteristics. Mice that received Dox developed heart failure and showed significant differences in body weight, ejection fraction (EF), end-systolic volume (ESV), stroke volume (SV), heart rate and QT and corrected QT (QTc) intervals when compared to the control group. After cell or placebo injection, the Dox + CM-mESC group showed significant increases in EF and SV when compared to the Dox + placebo group. Reduction in ESV and QT and QTc intervals in Dox + CM-mESC-treated mice was observed at 5 or 30 days after cell treatment. Cells were detected up to 11 days after injection. The Dox + CM-mESC group showed a significant reduction in the percentage of apoptotic cardiomyocytes in the hearts of mice when compared to the Dox + placebo group.

CONCLUSIONS

CM-mESC transplantation improves cardiac function in mice with DIC.