Inhibition of Rac1 signaling by lovastatin protects against anthracycline-induced cardiac toxicity

Statins in Mitigating Anticancer Treatment-Related Cardiovascular Disease

Certain anticancer therapies inevitably increase the risk of cardiovascular events, now the second leading cause of death among cancer patients. This underscores the critical need for developing effective drugs or regimens for cardiovascular protection. Statins possess properties such as antioxidative stress, anti-inflammatory effects, antifibrotic activity, endothelial protection, and immune modulation. These pathological processes are central to the cardiotoxicity associated with anticancer treatment. There is prospective clinical evidence confirming the protective role of statins in chemotherapy-induced cardiotoxicity. Numerous preclinical studies have demonstrated that statins can ameliorate heart and endothelial damage caused by radiotherapy, although clinical studies are scarce. In the animal models of trastuzumab-induced cardiomyopathy, statins provide protection through anti-inflammatory, antioxidant, and antifibrotic mechanisms. In animal and cell models, statins can mitigate inflammation, endothelial damage, and cardiac injury induced by immune checkpoint inhibitors. Chimeric antigen receptor (CAR)-T cell therapy-induced cardiotoxicity and immune effector cell-associated neurotoxicity syndrome are associated with uncontrolled inflammation and immune activation. Due to their anti-inflammatory and immunomodulatory effects, statins have been used to manage CAR-T cell therapy-induced immune effector cell-associated neurotoxicity syndrome in a clinical trial. However, direct evidence proving that statins can mitigate CAR-T cell therapy-induced cardiotoxicity is still lacking. This review summarizes the possible mechanisms of anticancer therapy-induced cardiotoxicity and the potential mechanisms by which statins may reduce related cardiac damage. We also discuss the current status of research on the protective effect of statins in anticancer treatment-related cardiovascular disease and provide directions for future research. Additionally, we propose further studies on using statins for the prevention of cardiovascular disease in anticancer treatment.

Screening and genetic engineering of marine-derived Aspergillus terreus for high-efficient production of lovastatin

BACKGROUND

Lovastatin has widespread applications thanks to its multiple pharmacological effects. Fermentation by filamentous fungi represents the major way of lovastatin production. However, the current lovastatin productivity by fungal fermentation is limited and needs to be improved.

RESULTS

In this study, the lovastatin-producing strains of Aspergillus terreus from marine environment were screened, and their lovastatin productions were further improved by genetic engineering. Five strains of A. terreus were isolated from various marine environments. Their secondary metabolites were profiled by metabolomics analysis using Ultra Performance Liquid Chromatography-Mass spectrometry (UPLC-MS) with Global Natural Products Social Molecular Networking (GNPS), revealing that the production of secondary metabolites was variable among different strains. Remarkably, the strain of A. terreus MJ106 could principally biosynthesize the target drug lovastatin, which was confirmed by High Performance Liquid Chromatography (HPLC) and gene expression analysis. By one-factor experiment, lactose was found to be the best carbon source for A. terreus MJ106 to produce lovastatin. To improve the lovastatin titer in A. terreus MJ106, genetic engineering was applied to this strain. Firstly, a series of strong promoters was identified by transcriptomic and green fluorescent protein reporter analysis. Then, three selected strong promoters were used to overexpress the transcription factor gene lovE encoding the major transactivator for lov gene cluster expression. The results revealed that compared to A. terreus MJ106, all lovE over-expression mutants exhibited significantly more production of lovastatin and higher gene expression. One of them, LovE-b19, showed the highest lovastatin productivity at a titer of 1512 mg/L, which represents the highest production level reported in A. terreus.

CONCLUSION

Our data suggested that combination of strain screen and genetic engineering represents a powerful tool for improving the productivity of fungal secondary metabolites, which could be adopted for large-scale production of lovastatin in marine-derived A. terreus.

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.

Anthracycline-induced cardiotoxicity: mechanisms, monitoring, and prevention

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

Endothelial-to-Mesenchymal Transition: Potential Target of Doxorubicin-Induced Cardiotoxicity

The use of chemotherapeutic agents is becoming more frequent as the proportion of new oncology patients increases worldwide, with prolonged survival after treatment. As one of the most popular chemotherapy drugs, doxorubicin plays a substantial role in the treatment of tumors. Unfortunately, the use of doxorubicin is associated with several adverse effects, particularly severe cardiotoxicity that can be life-threatening, which greatly limits its clinical use. For decades, scientists have tried to explore many cardioprotective agents and therapeutic approaches, but their efficacy remains controversial, and some drugs have even brought about significant adverse effects. The concrete molecular mechanism of doxorubicin-induced cardiotoxicity is still to be unraveled, yet endothelial damage is gradually being identified as an important mechanism triggering the development and progression of doxorubicin-induced cardiotoxicity. Endothelial-to-mesenchymal transition (EndMT), a fundamental process regulating morphogenesis in multicellular organisms, is recognized to be associated with endothelial damage repair and acts as an important factor in the progression of cardiovascular diseases, tumors, and rheumatic immune diseases. Mounting evidence suggests that endothelial-mesenchymal transition may play a non-negligible role in doxorubicin-induced cardiotoxicity. In this paper, we reviewed the molecular mechanisms and signaling pathways of EndMT and outlined the molecular mechanisms of doxorubicin-induced cardiotoxicity and the current therapeutic advances. Furthermore, we summarized the basic principles of doxorubicin-induced endothelial-mesenchymal transition that lead to endothelial dysfunction and cardiotoxicity, aiming to provide suggestions or new ideas for the prevention and treatment of doxorubicin-induced endothelial and cardiac injury.

Nuclear RAC1 is a modulator of the doxorubicin-induced DNA damage response

Rho GTPases like RAC1 are localized on the inner side of the outer cell membrane where they act as molecular switches that can trigger signal transduction pathways in response to various extracellular stimuli. Nuclear functions of RAC1 were identified that are related to mitosis, cell cycle arrest and apoptosis. Previously, we showed that RAC1 plays a role in the doxorubicin (Dox)-induced DNA damage response (DDR). In this context it is still unknown whether cytosolic RAC1 modulates the Dox-induced DDR or if a nuclear fraction of RAC1 is involved. Here, we silenced RAC1 in mouse embryonic fibroblasts (MEF) pharmacologically with EHT1864 or by using siRNA against Rac1. Additionally, we transfected MEF with RAC1 mutants (wild-type, dominant-negative, constitutively active) containing a nuclear localization sequence (NLS). Afterwards, we analysed the Dox-induced DDR by evaluation of fluorescent nuclear γH2AX and 53BP1 foci formation, as well as by detection of activated proteins of the DDR by western blot to elucidate the role of nuclear RAC1 in the DDR. Treatment with EHT1864 as well as Rac1 knock-down reduced the Dox-induced DSB-formation to a similar extent. Enhanced nuclear localization of dominant-negative as well as constitutively active RAC1 mimicked these effects. Expression of the RAC1 mutants altered the Dox-induced amount of pP53 and pKAP1 protein. The observed effects were independent of S1981 ATM phosphorylation. We conclude that RAC1 is required for a substantial activation of the Dox-induced DDR and balanced levels of active/inactive RAC1 inside the nucleus are a prerequisite for this response.

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.

Novel Therapeutics for Anthracycline Induced Cardiotoxicity

Anthracyclines remain an essential component of the treatment of many hematologic and solid organ malignancies, but has important implications on cardiovascular disease. Anthracycline induced cardiotoxicity (AIC) ranges from asymptomatic LV dysfunction to highly morbid end- stage heart failure. As cancer survivorship improves, the detection and treatment of AIC becomes more crucial to improve patient outcomes. Current treatment modalities for AIC have been largely extrapolated from treatment of conventional heart failure, but developing effective therapies specific to AIC is an area of growing research interest. This review summarizes the current evidence behind the use of neurohormonal agents, dexrazoxane, and resynchronization therapy in AIC, evaluates the clinical outcomes of advanced therapy and heart transplantation in AIC, and explores future horizons for treatment utilizing gene therapy, stem cell therapy, and mechanism-specific targets.

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.

An Injectable In Situ Depot-Forming Lipidic Lyotropic Liquid Crystal System for Localized Intratumoral Drug Delivery

To address the need for localized chemotherapy against unresectable solid tumors, an injectable in situ depot-forming lipidic lyotropic liquid crystal system (L3CS) is explored that can provide spatiotemporal control over drug delivery. Although liquid crystals have been studied extensively before but their application as an injectable intratumoral depot system for locoregional chemotherapy has not been explored yet. The developed L3CS in the present study is a low-viscosity injectable fluid having a lamellar phase, which transforms into a hexagonal mesophase depot system on subcutaneous or intratumoral injection. The transformed depot system can be preprogrammed to provide tailored drug release intratumorally, over a period of one week to one month. To establish the efficacy of the developed L3CS, doxorubicin is used as a model drug. The drug release mechanism is studied in detail both in vitro and in vivo, and the efficacy of the developed system is investigated in the murine 4T1 tumor model. The direct intratumoral injection of the L3CS provided localized delivery of doxorubicin inside the tumor and restricted its access within the tumor only for a sustained period of time. This led to an over 10-fold reduction in tumor burden, reduced cardiotoxicity, and a significant increase in the median survival rate, compared to the control group. The developed L3CS thus provides an efficient strategy for localized chemotherapy against unresectable solid tumors with a great degree of spatial and temporal control over drug delivery.

Chemotherapy-associated cardiomyopathy: Mechanisms of toxicity and cardioprotective strategies

OBJECTIVE

To describe the proposed mechanisms of chemotherapy-associated cardiomyopathy (CAC) and potential cardioprotective therapies for CAC including a comprehensive review of existing systematic analyses, guideline recommendations, and ongoing clinical trials.

DATA SOURCES

A literature search of MEDLINE was performed (from 1990 to June 2020) using the following search terms: anthracycline, trastuzumab, cardiomyopathy, cardiotoxicity, primary prevention, angiotensin-converting enzyme inhibitor (ACEI), angiotensin receptor blocker (ARB), beta blocker, dexrazoxane (DEX) as well as using individual names from select therapeutic categories.

STUDY SELECTION AND DATA EXTRACTION

Existing English language systematic analyses and guidelines were considered.

DATA SYNTHESIS

The mechanisms of CAC are multifaceted, but various cardioprotective therapies target many of these pathways. To date, anthracyclines and HER-2 targeted therapies have been the focus of cardioprotective trials to date as they are the most commonly implicated therapies in CAC. While traditional neurohormonal antagonists (ACEIs, ARBs, and beta blockers) and DEX performed favorably in many small clinical trials, the quality of available evidence remains limited. Hence, major guidelines lack consensus on an approach to primary prevention of CAC. Given the uncertain role of preventive therapy, monitoring for a symptomatic or asymptomatic decline in LV function is imperative with prompt evaluation should this occur. Numerous ongoing randomized controlled trials seek to either confirm the findings of these previous studies or identify new therapeutic agents to prevent CAC. Clinical implications are derived from the available literature as well as current guideline recommendations for CAC cardioprotection.

CONCLUSION

At this time, no single therapy has a clear cardioprotective benefit in preventing CAC nor is any therapy strongly recommended by current guidelines. Additional studies are needed to determine the optimal preventative regimens.

Preventing and Treating Anthracycline Cardiotoxicity: New Insights

Anthracyclines are the cornerstone of many chemotherapy regimens for a variety of cancers. Unfortunately, their use is limited by a cumulative dose-dependent cardiotoxicity. Despite more than five decades of research, the biological mechanisms underlying anthracycline cardiotoxicity are not completely understood. In this review, we discuss the incidence, risk factors, types, and pathophysiology of anthracycline cardiotoxicity, as well as methods to prevent and treat this condition. We also summarize and discuss advances made in the last decade in the comprehension of the molecular mechanisms underlying the pathology.

Anthracycline Induced Cardiac Disorders in Childhood Acute Lymphoblastic Leukemia: A Single-Centre, Retrospective, Observational Study

Anthracycline-associated cardiotoxicity is frequently seen in cancer survivors years after treatment, but it is rare in patients on chemotherapy. This study aimed to investigate the clinical characteristics of cardiac disorders in children with acute lymphoblastic leukemia (ALL) during chemotherapy. A retrospective case study was conducted in children with ALL, for whom electrocardiogram (ECG) and echocardiography (Echo) were regularly assessed before each course of chemotherapy. The cardiac disorders were diagnosed according to the Common Terminology Criteria for Adverse Events (CTCAE) Version 5.0. Binary logistic regression analysis was used to identify risk factors associated with cardiac disorders. There were 171 children eligible for the study, and 78 patients (45.61%) were confirmed as having cardiac disorders. The incidence of cardiac disorders was dependent upon the cumulative dose of daunorubicin (DNR) (p = 0.030, OR = 1.553, 95% CI: 1.005–3.108). Four patients (2.34%) presented with palpitation, chest pain, and persistent tachycardia, and they were cured or improved after medical intervention. A total of 74 patients (43.27%) had subclinical cardiac disorders confirmed by ECG or Echo. ECG abnormalities were commonly seen in the induction and continuation treatments, including arrhythmias (26, 15.20%), ST changes (24, 14.04%) and conduction disorders (4, 2.34%). Pericardial effusion (14, 8.19%), left ventricular hypertrophy (11, 6.43%), a widened pulmonary artery (5, 2.92%) and valvular insufficiency (5, 2.92%) suggested by Echo occurred after induction chemotherapy. Therefore, cardiac disorders with clinical manifestations are rare and need early intervention. Subclinical cardiac disorders are common but very hidden in children during ALL chemotherapy. Regular ECG and Echo could help paediatricians to identify and monitor patients with asymptomatic cardiac disorders earlier.

Role of Small GTPase RhoA in DNA Damage Response

Accumulating evidence has suggested a role of the small GTPase Ras homolog gene family member A (RhoA) in DNA damage response (DDR) in addition to its traditional function of regulating cell morphology. In DDR, 2 key components of DNA repair, ataxia telangiectasia-mutated (ATM) and flap structure-specific endonuclease 1 (FEN1), along with intracellular reactive oxygen species (ROS) have been shown to regulate RhoA activation. In addition, Rho-specific guanine exchange factors (GEFs), neuroepithelial transforming gene 1 (Net1) and epithelial cell transforming sequence 2 (Ect2), have specific functions in DDR, and they also participate in Ras-related C3 botulinum toxin substrate 1 (Rac1)/RhoA interaction, a process which is largely unappreciated yet possibly of significance in DDR. Downstream of RhoA, current evidence has highlighted its role in mediating cell cycle arrest, which is an important step in DNA repair. Unraveling the mechanism by which RhoA modulates DDR may provide more insight into DDR itself and may aid in the future development of cancer therapies.

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.

[Molecular mechanisms of the cardiotoxic action of anthracycline antibiotics and statin-induced cytoprotective reactions of cardiomyocytes]

The manifestation of the side cardiotoxic effect of anthracycline antibiotics limits their use in the treatment of malignant processes in some patients. The review analyzes the main causes of the susceptibility of cardiomyocytes to the damaging effect of anthracyclines, primarily associated with an increase in the processes of free radical oxidation. Currently, research is widely carried out to find ways to reduce anthracycline cardiotoxicity, in particular, the use of cardioprotective agents in the complex treatment of tumors. Hydroxymethylglutaryl coenzyme A reductase inhibitors (statins) have been shown to improve the function and metabolism of the cardiovascular system under various pathological impacts, therefore, it is proposed to use them to reduce cardiotoxic complications of chemotherapy. Statins exhibit direct (hypolipidemic) and pleiotropic effects due to the blockade of mevalonic acid synthesis and downward biochemical cascades that determine their cardioprotective properties. The main point of intersection of the pharmacological activity of anthracyclines and statins is the ability of both to regulate the functioning of small GTPase from the Rho family, and their effect in this regard is the opposite. The influence of statins on the modification and membrane dislocation of Rho proteins mediates the indirect antioxidant, anti-inflammatory, endothelioprotective, antiapoptotic effect. The mechanism of statin inhibition of doxorubicin blockade of the DNA-topoisomerase complex, which may be important in preventing cardiotoxic damage during chemotherapy, is discussed. At the same time, it should be noted that the use of statins can be accompanied by adverse side effects: a provocation of increased insulin resistance and glucose tolerance, which often causes them to be canceled in patients with impaired carbohydrate metabolism, so further studies are needed here. The review also analyzes data on the antitumor effect of statins, their ability to sensitize the tumor to treatment with cytostatic drug. It has been shown that the relationship between anthracycline antibiotics and statins is characterized not only by antagonism, but also in some cases by synergism. Despite some adverse effects, statins are one of the most promising cardio- and vasoprotectors for use in anthracycline cardiomyopathy.

An Overview of Pharmacological and Non-Pharmacological Treatment as a Useful Tool for the Protection from Cardiotoxicity of Antineoplastic Drugs

Unfortunately, in patients with cancer disease, clinical application of antineoplastic drug results in severe side effects of cardiotoxicity.

We aim to review the research focused on elimination or reduction of antineoplastic drug-induced cardiotoxicity without affecting its anticancer efficacy by different agens.

This study is based on pertinent papers that were retrieved by a selective search using relevant keywords in PubMed and ScienceDirect. Based on mentioned purpose, various strategies were investigated and proposed, and thousands of compounds were screened. The literature mainly focusing on drugs, natural products and herb extracts with therapeutic efficacies as well as non-pharmacological treatment against differently induced cardiotoxicity during treatment in patients with cancers.

Larger future studies are necessary to reach a point of secure cytostatic therapy, improved patient survival and quality of life. Until that moment, baseline and serial cardiac evaluation is recommended to facilitate early identification and treatment of cardiotoxicity.

The Long-Lasting Protective Effect of HGF in Cardiomyoblasts Exposed to Doxorubicin Requires a Positive Feed-Forward Loop Mediated by Erk1,2-Timp1-Stat3

Previous studies showed that the hepatocyte growth factor (HGF)–Met receptor axis plays long-lasting cardioprotection against doxorubicin anti-cancer therapy. Here, we explored the mechanism(s) underlying the HGF protective effect. DNA damage was monitored by histone H2AX phosphorylation and apoptosis by proteolytic cleavage of caspase 3. In doxorubicin-treated H9c2 cardiomyoblasts, the long-lasting cardioprotection is mediated by activation of the Ras/Raf/Mek/Erk (extracellular signal-regulated kinase 1,2) signaling pathway and requires Stat3 (signal transducer and activator of transcription 3) activation. The HGF protection was abrogated by the Erk1,2 inhibitor, PD98059. This translated into reduced Y705 phosphorylation and impaired nuclear translocation of Stat3, showing crosstalk between Erk1,2 and Stat3 signaling. An array of 29 cytokines, known to activate Stat3, was interrogated to identify the molecule(s) linking the two pathways. The analysis showed a selective increase in expression of the tissue inhibitor of metalloproteinases-1 (Timp1). Consistently, inhibition in cardiomyoblasts of Timp1 translation by siRNAs blunted both Stat3 activation and the cardioprotective effect of HGF. Thus, Timp1 is responsible for the generation of a feed-forward loop of Stat3 activation and helps cardiomyocytes to survive during the genotoxic stress induced by anthracyclines.

Activation of the MET receptor attenuates doxorubicin-induced cardiotoxicity in vivo and in vitro

Background and Purpose

Doxorubicin anti‐cancer therapy is associated with cardiotoxicity, resulting from DNA damage response (DDR). Hepatocyte growth factor (HGF) protects cardiomyocytes from injury, but its effective use is compromised by low biodistribution. In this study, we have investigated whether the activation of the HGF receptor—encoded by the Met gene—by an agonist monoclonal antibody (mAb) could protect against doxorubicin‐induced cardiotoxicity.

Experimental Approach

The mAb (5 mg·kg⁻¹) was injected in vivo into C57BL/6J mice, before doxorubicin (three doses of 7 mg·kg⁻¹). Cardiac functions were evaluated through MRI after treatment termination. Heart histological staining and mRNA levels of genes associated with heart failure (Acta1 and Nppa), inflammation (IL‐6), and fibrosis (Ctgf, Col1a2, Timp1, and Mmp9) were assessed. MAb (100 nM) was administered in vitro to H9c2 cardiomyoblasts before addition of doxorubicin (25 μM). DDR and apoptosis markers were evaluated by quantitative western blotting, flow cytometry, and immunofluorescence. Stattic was used for pharmacological inactivation of STAT3.

Key Results

In vivo, administration of the mAb alleviated doxorubicin‐induced cardiac dysfunction and fibrosis. In vitro, mAb mimicked the response to HGF by (a) inhibiting histone H2AX phosphorylation at S139, (b) quenching the expression of the DNA repair enzyme PARP1, and (c) reducing the proteolytic activation of caspase 3. The MET‐driven cardioprotection involved, at least in vitro, the phosphorylation of STAT3.

Conclusion and Implications

The MET agonist mAb provides a new tool for cardioprotection against anthracycline cardiotoxicity.

Effects of doxorubicin-induced cardiotoxicity on cardiac mitochondrial dynamics and mitochondrial function: Insights for future interventions

Anthracyclines is an effective chemotherapeutic treatment used for many types of cancer. However, high cumulative dosage of anthracyclines leads to cardiac toxicity and heart failure. Dysregulation of mitochondrial dynamics and function are major pathways driving this toxicity. Several pharmacological and non‐pharmacological interventions aiming to attenuate cardiac toxicity by targeting mitochondrial dynamics and function have shown beneficial effects in cell and animal models. However, in clinical practice, there is currently no standard therapy for the prevention of anthracycline‐induced cardiotoxicity. This review summarizes current reports on the impact of anthracyclines on cardiac mitochondrial dynamics and mitochondrial function and potential interventions targeting these pathways. The roles of mitochondrial dynamics and mitochondrial function in the development of anthracycline‐induced cardiotoxicity should provide insights in devising novel strategies to attenuate the cardiac toxicity induced by anthracyclines.

Restoring Treatment Response in Colorectal Cancer Cells by Targeting MACC1-Dependent ABCB1 Expression in Combination Therapy

Treatment failure of solid cancers, represented by the development of drug resistance in the primary tumor or later outgrowth of drug resistant metastases, is the major cause of death for cancer patients. It represents an urgent clinical need for predictive biomarkers which indicate the success or failure of standard treatment regimens. Besides treatment prediction, interfering with cellular processes associated with drug resistance might improve treatment response by applying combination therapies. Metastasis-associated in colon cancer (MACC) 1 was identified in our group as a prognostic biomarker in human colorectal cancer, and has been established as key player, prognostic, and predictive biomarker for tumor progression and metastasis in a variety of solid cancers. Besides increased cell proliferation and motility, subsequently contributing to growth and metastatic spread of the primary tumor, MACC1 has also been shown to dysregulate apoptosis and is contributing to treatment resistance. Here we report the MACC1 dependent treatment resistance of colorectal cancer (CRC) cells to standard therapeutics like doxorubicin by upregulating ATP-binding cassette subfamily B member 1 (ABCB1) protein. Overexpression of MACC1 in CRC cells increased both its presence on the ABCB1 promoter and its transcriptional activity, resulting in elevated ABCB1 expression and thus treatment resistance to standard therapeutics. In contrast, depleting MACC1 increased intracellular drug concentrations, leading to better treatment response. We already identified the first MACC1 transcriptional inhibitors, such as lovastatin, by high-throughput screening of clinically approved small molecule drugs. These compounds inhibited cell motility in vitro but also restricted metastasis development in xenograft mouse models by reducing MACC1 expression. Here we report, that treating high MACC1 expressing CRC cells with a combination of statins and standard therapeutics increased the rate of cytotoxicity and resulted in higher treatment response.

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.

Targeting the DNA damage response (DDR) by natural compounds

Natural compounds (NC) are an important source of anticancer drugs. The genomic DNA of tumor cells is a major target of conventional anticancer therapeutics (cAT). DNA damage elicits a complex stress response programme termed DNA damage response (DDR), with the PI3-like kinase ATM and ATR being the key regulators. Since the DDR coordinates mechanisms of DNA repair and apoptosis, hence regulating the balance between death and survival, it is an attractive target of novel anticancer strategies. The aim of the study was to identify natural compounds derived from endophytic fungi, lichens, marine sponges or plants that interfere with mechanisms of the DDR. To this end, the cytotoxic and DDR modulating potency of 296 natural compounds, used alone or in combination with the cAT cisplatin (Cis) and doxorubicin (Doxo) was investigated by fluorescence-based analysis of the ATM/ATR-catalyzed S139 phosphorylation of histone 2AX (γH2AX), a surrogate marker of DNA damage-triggered DDR. After initial screening, a total of ten natural compounds were identified that were toxic in pancreatic carcinoma cells and activated the DDR on their own and/or promoted the DDR if used in combination with cAT. Their mode of action was shown to be independent of drug transport mechanisms. Based on their chemical structures, DDR modulatory activity and published data we suggest the marine NC 5-epi-nakijiquinone Q and 5-epi-ilimaquinone as well as the fungal compound secalonic acid F as most promising NC-based drug candidates for future synthesis of DDR-modulating chemical derivatives and their preclinical in vitro and in vivo testing.

Cancer Therapy-Related Cardiac Dysfunction: An Overview for the Clinician

Cancer therapy-related cardiac dysfunction (CTRCD) is one of the most feared and undesirable side effects of chemotherapy, occurring in approximately 10% of the patients. It can be classified as direct (dose-dependent vs dose-independent) or indirect, either case being potentially permanent or reversible. Risk assessment, recognition, and prevention of CTRCD are crucial.

From Molecular Mechanisms to Clinical Management of Antineoplastic Drug-Induced Cardiovascular Toxicity: A Translational Overview

Significance: Antineoplastic therapies have significantly improved the prognosis of oncology patients. However, these treatments can bring to a higher incidence of side-effects, including the worrying cardiovascular toxicity (CTX). Recent Advances: Substantial evidence indicates multiple mechanisms of CTX, with redox mechanisms playing a key role. Recent data singled out mitochondria as key targets for antineoplastic drug-induced CTX; understanding the underlying mechanisms is, therefore, crucial for effective cardioprotection, without compromising the efficacy of anti-cancer treatments. Critical Issues: CTX can occur within a few days or many years after treatment. Type I CTX is associated with irreversible cardiac cell injury, and it is typically caused by anthracyclines and traditional chemotherapeutics. Type II CTX is generally caused by novel biologics and more targeted drugs, and it is associated with reversible myocardial dysfunction. Therefore, patients undergoing anti-cancer treatments should be closely monitored, and patients at risk of CTX should be identified before beginning treatment to reduce CTX-related morbidity. Future Directions: Genetic profiling of clinical risk factors and an integrated approach using molecular, imaging, and clinical data may allow the recognition of patients who are at a high risk of developing chemotherapy-related CTX, and it may suggest methodologies to limit damage in a wider range of patients. The involvement of redox mechanisms in cancer biology and anticancer treatments is a very active field of research. Further investigations will be necessary to uncover the hallmarks of cancer from a redox perspective and to develop more efficacious antineoplastic therapies that also spare the cardiovascular system.

Distinct contribution of Rac1 expression in cardiomyocytes to anthracycline-induced cardiac injury

Cardiotoxicity is the dose limiting adverse effect of anthracycline-based anticancer therapy. Inhibitor studies point to Rac1 as therapeutic target to prevent anthracycline-induced cardiotoxicity. Yet, supporting genetic evidence is still missing and the pathophysiological relevance of different cardiac cell types is unclear. Here, we employed a tamoxifen-inducible cardiomyocyte-specific rac1 knock-out mouse model (Rac1^{flox/flox/MHC-MerCreMer}) to investigate the impact of Rac1 expression in cardiomyocytes on cardiac injury following doxorubicin treatment. Distinctive stress responses resulting from doxorubicin treatment were observed, including upregulation of systemic markers of inflammation (IL-6, IL-1α, MCP-1), cardiac damage (ANP, BNP), DNA damage (i.e. DNA double-strand breaks (DSB)), DNA damage response (DDR) and cell death. Measuring the acute doxorubicin response, the serum level of MCP-1 was elevated, cardiac mRNA expression of Hsp70 was reduced and cardiac DDR was specifically enhanced in Rac1 deficient mice. The frequency of apoptotic heart cells remained unaffected by Rac1. Employing a subactue model, the number of doxorubicin-induced DSB was significantly reduced if Rac1 is absent. Yet, the doxorubicin-triggered increase in serum ANP and BNP levels remained unaffected by Rac1. Overall, knock-out of rac1 in cardiomyocytes confers partial protection against doxorubicin-induced cardiac injury. Hence, the data provide first genetic evidence supporting the view that pharmacological targeting of Rac1 is useful to widen the therapeutic window of anthracycline-based anticancer therapy by alleviating acute/subacute cardiomyocyte damage. Furthermore, considering published data obtained from the use of pharmacological Rac1 inhibitors, the results of our study indicate that Rac1-regulated functions of cardiac cell types others than cardiomyocytes additionally influence the adverse outcomes of anthracycline treatment on the heart.

Influence of PARP-1 inhibition in the cardiotoxicity of the topoisomerase 2 inhibitors doxorubicin and mitoxantrone

Doxorubicin (DOX) and Mitoxantrone (MTX) are very effective drugs for a range of tumors despite being highly cardiotoxic. DNA topoisomerase 2 beta (Top2ß) was revealed as key mediator of DOX-induced cardiotoxicity, although ROS generation is also an important mechanism. Oxidative stress is also an important issue in MTX-induced cardiotoxicity that is manifested by mitochondrial dysfunction. Studies have demonstrated the relationship between PARP-1 overactivation and cell viability in DOX-treated cardiomyocytes. In reference of MTX, data regarding PARP-1 overactivation as the mechanism responsible for cardiotoxicity is difficult to find. The aim of this study was to evaluate the influence of PARP-1 inhibitor DPQ on DOX- and MTX-mediated cardiotoxicity. Cells were exposed for 24 h to DOX or MTX in the presence or absence of DPQ. Viability, apoptosis, and genotoxicity assays were carried out. Immunofluorescence of phosphorylated histone H2AX was analyzed in H9c2 cells and cardiomyocytes from neonatal rats. Results demonstrated that DPQ co-treatment increases DOX-induced apoptosis in H9c2 cells. DPQ also prevents DOX and MTX-ROS generation in part by increasing SOD and CAT activities. Furthermore, DPQ co-treatment increased the generation of DNA strand breaks by DOX and MTX whilst also inducing phosphorylation of H2AX, MRE11, and ATM in H9c2 cells. Our results demonstrated that as well as increasing DNA damage and inducing apoptotic cell death, DPQ enhances DOX- and MTX-mediated cytotoxicity in H9c2.

Sulforaphane protection against the development of doxorubicin-induced chronic heart failure is associated with Nrf2 Upregulation

BACKGROUND

Doxorubicin (DOX) is an anthracycline antitumor drug. However, its clinical use is limited by dose-dependent cardiotoxicity and even progresses to chronic heart failure (CHF).

OBJECTIVE

This study aims to investigate whether the Nrf2 activator, sulforaphane (SFN), can prevent DOX-induced CHF.

METHODS

Male Sprague-Dawley rats which received treatment for 6 weeks were divided into four groups (n=30 per group): control, SFN, DOX and DOX plus SFN group.

RESULTS

Results revealed that DOX induced progressive cardiac damage as indicated by increased cardiac injury markers, cardiac inflammation, fibrosis and oxidative stress. SFN significantly prevented DOX-induced progressive cardiac dysfunction between 2-6 weeks and prevented DOX-induced cardiac function deterioration. Furthermore, it significantly decreased ejection fraction and increased the expression of brain natriuretic peptide. SFN also almost completely prevented DOX-induced cardiac oxidative stress, inflammation and fibrosis. SFN upregulated NF-E2-related factor 2 (Nrf2) expression and transcription activity, which was reflected by the increased mRNA expression of Nrf2 and its downstream genes. Furthermore, in cultured H9c2 cardiomyocytes, the protective effect of SFN against DOX-induced fibrotic and inflammatory responses was abolished by Nrf2 silencing.

CONCLUSION

We arrived at the conclusion that DOX-induced CHF can be prevented by SFN through the upregulation of Nrf2 expression and transcriptional function.

Antineoplastic Drug-Induced Cardiotoxicity: A Redox Perspective

Antineoplastic drugs can be associated with several side effects, including cardiovascular toxicity (CTX). Biochemical studies have identified multiple mechanisms of CTX. Chemoterapeutic agents can alter redox homeostasis by increasing the production of reactive oxygen species (ROS) and reactive nitrogen species RNS. Cellular sources of ROS/RNS are cardiomyocytes, endothelial cells, stromal and inflammatory cells in the heart. Mitochondria, peroxisomes and other subcellular components are central hubs that control redox homeostasis. Mitochondria are central targets for antineoplastic drug-induced CTX. Understanding the mechanisms of CTX is fundamental for effective cardioprotection, without compromising the efficacy of anticancer treatments. Type 1 CTX is associated with irreversible cardiac cell injury and is typically caused by anthracyclines and conventional chemotherapeutic agents. Type 2 CTX, associated with reversible myocardial dysfunction, is generally caused by biologicals and targeted drugs. Although oxidative/nitrosative reactions play a central role in CTX caused by different antineoplastic drugs, additional mechanisms involving directly and indirectly cardiomyocytes and inflammatory cells play a role in cardiovascular toxicities. Identification of cardiologic risk factors and an integrated approach using molecular, imaging, and clinical data may allow the selection of patients at risk of developing chemotherapy-related CTX. Although the last decade has witnessed intense research related to the molecular and biochemical mechanisms of CTX of antineoplastic drugs, experimental and clinical studies are urgently needed to balance safety and efficacy of novel cancer therapies.

Mycobacterial Phenolic Glycolipids Selectively Disable TRIF-Dependent TLR4 Signaling in Macrophages

Phenolic glycolipids (PGLs) are cell wall components of a subset of pathogenic mycobacteria, with immunomodulatory properties. Here, we show that in addition, PGLs exert antibactericidal activity by limiting the production of nitric oxide synthase (iNOS) in mycobacteria-infected macrophages. PGL-mediated downregulation of iNOS was complement receptor 3-dependent and comparably induced by bacterial and purified PGLs. Using Mycobacterium leprae PGL-1 as a model, we found that PGLs dampen the toll-like receptor (TLR)4 signaling pathway, with macrophage exposure to PGLs leading to significant reduction in TIR-domain-containing adapter-inducing interferon-β (TRIF) protein level. PGL-driven decrease in TRIF operated posttranscriptionally and independently of Src-family tyrosine kinases, lysosomal and proteasomal degradation. It resulted in the defective production of TRIF-dependent IFN-β and CXCL10 in TLR4-stimulated macrophages, in addition to iNOS. Our results unravel a mechanism by which PGLs hijack both the bactericidal and inflammatory responses of host macrophages. Moreover, they identify TRIF as a critical node in the crosstalk between CR3 and TLR4.

Rho inhibition by lovastatin affects apoptosis and DSB repair of primary human lung cells in vitro and lung tissue in vivo following fractionated irradiation

Thoracic radiotherapy causes damage of normal lung tissue, which limits the cumulative radiation dose and, hence, confines the anticancer efficacy of radiotherapy and impacts the quality of life of tumor patients. Ras-homologous (Rho) small GTPases regulate multiple stress responses and cell death. Therefore, we investigated whether pharmacological targeting of Rho signaling by the HMG-CoA-reductase inhibitor lovastatin influences ionizing radiation (IR)-induced toxicity in primary human lung fibroblasts, lung epithelial and lung microvascular endothelial cells in vitro and subchronic mouse lung tissue damage following hypo-fractionated irradiation (4x4 Gy). The statin improved the repair of radiation-induced DNA double-strand breaks (DSBs) in all cell types and, moreover, protected lung endothelial cells from IR-induced caspase-dependent apoptosis, likely involving p53-regulated mechanisms. Under the in vivo situation, treatment with lovastatin or the Rac1-specific small molecule inhibitor EHT1864 attenuated the IR-induced increase in breathing frequency and reduced the percentage of γH2AX and 53BP1-positive cells. This indicates that inhibition of Rac1 signaling lowers IR-induced residual DNA damage by promoting DNA repair. Moreover, lovastatin and EHT1864 protected lung tissue from IR-triggered apoptosis and mitigated the IR-stimulated increase in regenerative proliferation. Our data document beneficial anti-apoptotic and genoprotective effects of pharmacological targeting of Rho signaling following hypo-fractionated irradiation of lung cells in vitro and in vivo. Rac1-targeting drugs might be particular useful for supportive care in radiation oncology and, moreover, applicable to improve the anticancer efficacy of radiotherapy by widening the therapeutic window of thoracic radiation exposure.

Rac1-mediated cardiac damage causes diastolic dysfunction in a mouse model of subacute doxorubicin-induced cardiotoxicity

The anticancer efficacy of anthracyclines is limited by congestive heart failure. Clinically established markers of early onset of cardiotoxicity following anthracycline treatment and preventive measures are missing. Although statins are reported to alleviate anthracycline-induced cardiotoxicity in vivo, the molecular mechanisms involved remain elusive. In vitro data point to Rac1 as major target of the cytoprotective statin effects. Here we investigated whether specific inhibition of Rac1 by NSC23766 is as effective as lovastatin in preventing subacute cardiotoxicity following doxorubicin treatment. C57BL/6 mice were treated over 3 weeks with multiple low doses of doxorubicin (6 × 3 mg/kg BW, i.p.) and the level of DNA damage, apoptosis and regenerative proliferation as well as pro-inflammatory, pro-fibrotic and oxidative stress responses were investigated. Moreover, heart function was monitored by echocardiography. Doxorubicin induced subacute cardiotoxicity which was reflected on the level of residual DNA damage, frequency of apoptotic and mitotic cells as well as elevated mRNA expression of markers of heart failure, remodeling and mitochondrial biogenesis. These molecular markers of cardiotoxicity were mitigated to a similar extent by co-treatment with either lovastatin (10 mg/kg BW, p.o.) or NSC23766 (5 mg/kg BW, i.p.) three times a week. Moreover, doxorubicin caused diastolic dysfunction as reflected by increased E-wave acceleration time (EAT), which again was prevented by pharmacological inhibition of Rac1. Inhibition of Rac1 signaling is of major relevance for the cardioprotective effects of lovastatin in the context of anthracycline-induced cardiotoxicity. Moreover, EAT is a useful marker of subacute cardiotoxicity caused by persisting harmful effects of doxorubicin.

Cardio-oncology: cardiovascular complications of cancer therapy

This paper focuses on three classes of commonly used anticancer drugs, which can cause cardiotoxicity: anthracyclines, monoclonal antibodies exemplified by trastuzumab and tyrosine kinase inhibitors. Anthracyclines can induce cardiomyocyte necrosis and fibrosis. Trastuzumab can cause cardiac stunning. The tyrosine kinase inhibitors can increase systemic arterial pressure and impair myocyte contractility. In addition, radiation therapy to the mediastinum or left chest can exacerbate the cardiotoxicity of these anticancer drugs and can also cause accelerated atherosclerosis, myocardial infarction, heart failure and arrhythmias. Left ventricular ejection fraction measurements are most commonly used to assess cardiac function in patients who receive chemo- or radiation-therapy. However, echocardiographic determinations of global longitudinal strain are more sensitive for detection of early left ventricular systolic dysfunction. Information on patient-risk stratification and monitoring is presented and guidelines for the medical treatment of cardiac dysfunction due to cancer therapies are summarized.

Preventing antiblastic drug-related cardiomyopathy: old and new therapeutic strategies

Because of the recent advances in chemotherapeutic protocols, cancer survival has improved significantly, although cardiovascular disease has become a major cause of morbidity and mortality among cancer survivors: in addition to the well-known cardiotoxicity (CTX) from anthracyclines, biologic drugs that target molecules that are active in cancer biology also interfere with cardiovascular homeostasis.Pharmacological and non-pharmacological strategies to protect the cardiovascular structure and function are the best approaches to reducing the prevalence of cardiomyopathy linked to anticancer drugs. Extensive efforts have been devoted to identifying and testing strategies to achieve this end, but little consensus has been reached on a common and shared operability.Timing, dose and mode of chemotherapy administration play a crucial role in the development of acute or late myocardial dysfunction. Primary prevention initiatives cover a wide area that ranges from conventional heart failure drugs, such as β-blockers and renin-angiotensin-aldosterone system antagonists to nutritional supplementation and physical training. Additional studies on the pathophysiology and cellular mechanisms of anticancer-drug-related CTX will enable the introduction of novel therapies.We present various typologies of prevention strategies, describing the approaches that have already been used and those that could be effective on the basis of a better understanding of pharmacokinetic and pharmacodynamic CTX mechanisms.

Statins in anthracycline-induced cardiotoxicity: Rac and Rho, and the heartbreakers

Cancer patients receiving anthracycline-based chemotherapy are at risk to develop life-threatening chronic cardiotoxicity with the pathophysiological mechanism of action not fully understood. Besides the most common hypothesis that anthracycline-induced congestive heart failure (CHF) is mainly caused by generation of reactive oxygen species, recent data point to a critical role of topoisomerase II beta (TOP2B), which is a primary target of anthracycline poisoning, in the pathophysiology of CHF. As the use of the only clinically approved cardioprotectant dexrazoxane has been limited by the FDA in 2011, there is an urgent need for alternative cardioprotective measures. Statins are anti-inflammatory and anti-oxidative drugs that are clinically well established for the prevention of cardiovascular diseases. They exhibit pleiotropic beneficial properties beyond cholesterol-lowering effects that most likely rest on the indirect inhibition of small Ras homologous (Rho) GTPases. The Rho GTPase Rac1 has been shown to be a major factor in the regulation of the pro-oxidative NADPH oxidase as well as in the regulation of type II topoisomerase. Both are discussed to play an important role in the pathophysiology of anthracycline-induced CHF. Therefore, off-label use of statins or novel Rac1 inhibitors might represent a promising pharmacological approach to gain control over chronic cardiotoxicity by interfering with key mechanisms of anthracycline-induced cardiomyocyte cell death.

Successful recovery and allogeneic stem cell transplant following chemotherapy-induced severe cardiomyopathy: literature review of management and prognostic factors

Chemotherapy-induced cardiomyopathy is one of the major possible hazards that can result from potential cardiotoxic agents while treating cancer. Prognostic risk factors include the rate of drug administration, history of hypertension, female gender, extremes of age, previous history of mediastinal irradiation, cumulative dose and pre-existing heart disease. Close monitoring of the patients, timely diagnosis, use of well-known biomarkers including cardiac troponins, NT-ProBNP and imaging studies like 2D Echo or cardiac MRI are essential. Emerging biomarkers include carbonyl reductases (CBR1 and CBR3), aldo-keto reductases (AKR, type 1A1, 1C3, 7A2) and topoisomerase2β (Top2β). β blockers and ACE inhibitors have not only been shown to slow down the progression of cardiac dysfunction but also produce symptomatic improvement. Our case report describes a patient with acute myeloblastic leukaemia who developed severe cardiomyopathy acutely after starting the anthracycline-based regimen. Nevertheless, with timely intervention her symptoms improved and subsequently she successfully received allogeneic stem cell transplantation.

Improving the preclinical models for the study of chemotherapy-induced cardiotoxicity: a Position Paper of the Italian Working Group on Drug Cardiotoxicity and Cardioprotection

Although treatment for heart failure induced by cancer therapy has improved in recent years, the prevalence of cardiomyopathy due to antineoplastic therapy remains significant worldwide. In addition to traditional mediators of myocardial damage, such as reactive oxygen species, new pathways and target cells should be considered responsible for the impairment of cardiac function during anticancer treatment. Accordingly, there is a need to develop novel therapeutic strategies to protect the heart from pharmacologic injury, and improve clinical outcomes in cancer patients. The development of novel protective therapies requires testing putative therapeutic strategies in appropriate animal models of chemotherapy-induced cardiomyopathy. This Position Paper of the Working Group on Drug Cardiotoxicity and Cardioprotection of the Italian Society of Cardiology aims to: (1) define the distinctive etiopatogenetic features of cardiac toxicity induced by cancer therapy in humans, which include new aspects of mitochondrial function and oxidative stress, neuregulin-1 modulation through the ErbB receptor family, angiogenesis inhibition, and cardiac stem cell depletion and/or dysfunction; (2) review the new, more promising therapeutic strategies for cardioprotection, aimed to increase the survival of patients with severe antineoplastic-induced cardiotoxicity; (3) recommend the distinctive pathological features of cardiotoxicity induced by cancer therapy in humans that should be present in animal models used to identify or to test new cardioprotective therapies.

Cardiotoxicity of anthracycline therapy: current perspectives

Anthracyclines, especially doxorubicin and daunorubicin, are the drugs of first choice in the treatment of patients with hematologic malignancies, soft-tissue sarcomas, and solid tumors. Unfortunately, the use of anthracyclines is limited by their dose-dependent and cumulative cardiotoxicity. The molecular mechanism responsible for anthracycline-induced cardiotoxicity remains poorly understood, although experimental and clinical studies have shown that oxidative stress plays the main role. Hence, antioxidant agents, especially dexrazoxane, and also other drug classes (statins, β-blockers) proved to have a beneficial effect in protecting against anthracycline-induced cardiotoxicity. According to previous clinical trials, the major high-risk factors for anthracycline-induced cardiotoxicity are age, body weight, female gender, radiotherapy, and other diseases such as Down syndrome, familial dilated cardiomyopathy, diabetes and hypertension. Consequently, further studies are needed to elucidate the molecular pathogenesis of anthracycline-induced cardiotoxicity and also to discover new cardioprotective agents against anthracycline-induced cardiotoxicity.

Lovastatin protects keratinocytes from DNA damage-related pro-apoptotic stress responses stimulated by anticancer therapeutics

BACKGROUND

Oral mucositis (OM) is a relevant adverse effect of anticancer therapy involving ionizing radiation (IR) and doxorubicin (Doxo). Because DNA damage of keratinocytes is causative for the pathogenesis of OM, we aim to identify pharmacological measures for geno- and cytoprotection of keratinocytes.

METHODS

We investigated the influence of the lipid-lowering drug lovastatin on cell death, proliferation and DNA damage response (DDR) mechanisms of human keratinocytes following treatment with IR and Doxo.

RESULTS

Lovastatin protected keratinocytes from the cytotoxic and genotoxic effects of IR and Doxo as shown by a diminished induction of apoptosis as well as a reduced formation and slightly improved repair of DNA damage following Doxo and IR treatment, respectively. Lovastatin selectively blocked the activation of Chk1 and ATR kinases following treatment with IR, Doxo and the ribonucleotide reductase inhibitor hydroxyurea, indicating that the statin antagonizes ATR/Chk1-regulated replicative stress responses. Part of the cytoprotective activity of lovastatin seems to rest on a delayed entry of lovastatin treated cells into S-phase. Yet, because the statin also protected non-proliferating keratinocytes from IR- and Doxo-induced cytotoxicity, cell cycle independent protective mechanisms are involved, too.

CONCLUSIONS

Lovastatin attenuates pro-toxic DNA damage-related responses of keratinocytes stimulated by OM-inducing anticancer therapeutics. The data encourage forthcoming in vivo and clinical studies addressing the usefulness of statins in the prevention of OM.

Cancer Therapy-Related Cardiac Dysfunction and Heart Failure: Part 2: Prevention, Treatment, Guidelines, and Future Directions

Success with oncologic treatment has allowed cancer patients to experience longer cancer-free survival gains. Unfortunately, this success has been tempered by unintended and often devastating cardiac complications affecting overall patient outcomes. Cardiac toxicity, specifically the association of several cancer therapy agents with the development of left ventricular dysfunction and cardiomyopathy, is an issue of growing concern. Although the pathophysiologic mechanisms behind cardiac toxicity have been characterized, there is currently no evidence-based approach for monitoring and management of these patients. In the first of a 2-part review, we discuss the epidemiologic, pathophysiologic, risk factors, and imaging aspects of cancer therapy-related cardiac dysfunction and heart failure. In this second part, we discuss the prevention and treatment aspects in these patients and conclude with highlighting the evidence gaps and future directions for research in this area.

Concepts in cardio-oncology: definitions, mechanisms, diagnosis and treatment strategies of cancer therapy-induced cardiotoxicity

There has been considerable improvement in cancer survival rates, primarily through improved preventive strategies and novel anticancer drugs. Cancer is now becoming a chronic illness and as such both short and long-term cardiotoxic effects of cancer therapy are becoming more apparent. This has led to the emergence of a new multidisciplinary specialty known as cardio-oncology, with the purpose of identifying patients who are at a higher risk for developing cardiotoxicity so that appropriate surveillance, treatment and follow-up strategies may be instituted early. The mechanisms of cardiotoxicity caused by commonly used anticancer agents are reviewed, along with the latest advances in diagnostic and preventative strategies, with the overall objective of allowing cancer patients to continue both lifesaving and palliative treatments for their malignancy.

New signal transduction paradigms in anthracycline-induced cardiotoxicity

Anthracyclines, such as doxorubicin, are the most potent and widely used chemotherapeutic agents for the treatment of a variety of human cancers, including solid tumors and hematological malignancies. However, their clinical use is hampered by severe cardiotoxic side effects and cancer therapy-related heart disease has become a leading cause of morbidity and mortality among cancer survivors. The identification of therapeutic strategies limiting anthracycline cardiotoxicity with preserved antitumor efficacy thus represents the current challenge of cardio-oncologists. Anthracycline cardiotoxicity has been originally ascribed to the ability of this class of drugs to disrupt iron metabolism and generate excess of reactive oxygen species (ROS). However, small clinical trials with iron chelators and anti-oxidants failed to provide any benefit and suggested that doxorubicin cardiotoxicity is not solely due to redox cycling. New emerging explanations include anthracycline-dependent regulation of major signaling pathways controlling DNA damage response, cardiomyocyte survival, cardiac inflammation, energetic stress and gene expression modulation. This review will summarize recent studies unraveling the complex web of mechanisms of doxorubicin-mediated cardiotoxicity, and identifying new druggable players for the prevention of heart disease in cancer patients. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.

Lovastatin prevents bleomycin-induced DNA damage to HepG2 cells

Lovastatin as a member of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors is used as a lipid-lowering agent. It can also inhibit the formation of hydrogen peroxide and superoxide anion and finally leads to decline in oxidative stress processes. Here, we evaluated whether lovastatin can increase DNA damage resistance of HepG2 cells against genotoxicity of the anticancer drug bleomycin (BLM). HepG2 cells were incubated with different concentrations of lovastatin (0.1, 0.5, 1, 5 µM) before exposure to BLM (0.5 µg/mL for one h). The genotoxic dose of BLM and lovastatin was separately determined and comet assay was used to evaluate the genotoxicity. After trapping cells in agarose coated lames, they were lysed and the electrophoresis was done in alkaline pH, then colored and monitored by florescent microscope. The results of this study indicated that lovastatin in doses lower than 5 µM has genoprotective effect and in doses higher than 50 µM is genotoxic. In conclusion, lovastatin is able to protect genotoxic effects of BLM in HepG2 cells. Further studies are needed to elucidate the mechanism(s) involved in this process.

Lovastatin prevents cisplatin-induced activation of pro-apoptotic DNA damage response (DDR) of renal tubular epithelial cells

The platinating agent cisplatin (CisPt) is commonly used in the therapy of various types of solid tumors. The anticancer efficacy of CisPt largely depends on the formation of bivalent DNA intrastrand crosslinks, which stimulate mechanisms of the DNA damage response (DDR), thereby triggering checkpoint activation, gene expression and cell death. The clinically most relevant adverse effect associated with CisPt treatment is nephrotoxicity that results from damage to renal tubular epithelial cells. Here, we addressed the question whether the HMG-CoA-reductase inhibitor lovastatin affects the DDR of renal cells by employing rat renal proximal tubular epithelial (NRK-52E) cells as in vitro model. The data show that lovastatin has extensive inhibitory effects on CisPt-stimulated DDR of NRK-52E cells as reflected on the levels of phosphorylated ATM, Chk1, Chk2, p53 and Kap1. Mitigation of CisPt-induced DDR by lovastatin was independent of the formation of DNA damage as demonstrated by (i) the analysis of Pt-(GpG) intrastrand crosslink formation by Southwestern blot analyses and (ii) the generation of DNA strand breaks as analyzed on the level of nuclear γH2AX foci and employing the alkaline comet assay. Lovastatin protected NRK-52E cells from the cytotoxicity of high CisPt doses as shown by measuring cell viability, cellular impedance and flow cytometry-based analyses of cell death. Importantly, the statin also reduced the level of kidney DNA damage and apoptosis triggered by CisPt treatment of mice. The data show that the lipid-lowering drug lovastatin extensively counteracts pro-apoptotic signal mechanisms of the DDR of tubular epithelial cells following CisPt injury.

Breast Cancer Survivorship and Cardiovascular Disease: Emerging Approaches in Cardio-Oncology

OPINION STATEMENT

Cardiovascular disease (CVD) and breast cancer cause substantial morbidity and mortality in women and are major public health concerns in the USA. While aggressive screening and targeted, advanced treatment for breast cancer have had a measurable impact on breast cancer survival, treatment is not without significant cardiotoxic effects. Anthracycline-based chemotherapy can lead to left ventricular dysfunction and failure, as well as a decline in exercise tolerance and cardio-pulmonary reserve despite preserved ejection fraction. Trastuzumab, a newer monoclonal antibody targeting the Her2 receptor used in the treatment of Her2+ cancer, is also linked to left ventricular dysfunction, although the long-term cardiac effects are presently unclear. Radiation treatment particularly for left-sided breast cancer has been associated with increased rates of ischemic heart disease. As women have increasing survival and cure rates from early breast cancer, long-term consequences on the heart that are secondary to therapy are a major concern. These need to be identified, treated, and avoided when possible. Further research and clear surveillance guidelines are needed to aid the practicing clinician in CVD prevention in breast cancer survivors.