Nox2 NADPH oxidase promotes pathologic cardiac remodeling associated with Doxorubicin chemotherapy

NADPH oxidase 2 mediates cardiac sympathetic denervation and myocyte autophagy, resulting in cardiac atrophy and dysfunction in doxorubicin-induced cardiomyopathy

Doxorubicin has been used extensively as a potent anticancer agent, but its clinical use is limited by its cardiotoxicity. However, the underlying mechanisms remain to be fully elucidated. In this study, we tested whether NADPH oxidase 2 (Nox2) mediates cardiac sympathetic nerve terminal abnormalities and myocyte autophagy, resulting in cardiac atrophy and dysfunction in doxorubicin-induced heart failure. Nox2 knockout (KO) and wild-type (WT) mice were randomly assigned to receive a single injection of doxorubicin (15 mg/kg, i.p.) or saline. WT doxorubicin mice exhibited the decreases in survival rate, left ventricular (LV) wall thickness and LV fractional shortening and the increase in the lung wet-to-dry weight ratio 1 week after the injections. These alterations were attenuated in Nox2 KO doxorubicin mice. In WT doxorubicin mice, myocardial oxidative stress was increased, myocardial noradrenergic nerve fibers were reduced, myocardial expression of PGP9.5, GAP43, tyrosine hydroxylase and norepinephrine transporter was decreased, and these changes were prevented in Nox2 KO doxorubicin mice. Myocyte autophagy was increased and myocyte size was decreased in WT doxorubicin mice, but not in Nox2 KO doxorubicin mice. Nox2 mediates cardiac sympathetic nerve terminal abnormalities and myocyte autophagy-both of which contribute to cardiac atrophy and failure after doxorubicin treatment.

NADPH oxidase 2 inhibitor GSK2795039 prevents doxorubicin-induced cardiac atrophy by attenuating cardiac sympathetic nerve terminal abnormalities and myocyte autophagy

Doxorubicin is widely used for the treatment of human cancer, but its clinical use is limited by a cumulative dose-dependent cardiotoxicity. However, the mechanism of doxorubicin-induced cardiac atrophy and failure remains to be fully understood. In this study, we tested whether the specific NADPH oxidase 2 (Nox2) inhibitor GSK2795039 attenuates cardiac sympathetic nerve terminal abnormalities and myocyte autophagy, leading to the amelioration of cardiac atrophy and dysfunction in chronic doxorubicin-induced cardiomyopathy. Mice were randomized to receive saline, doxorubicin (2.5 mg/kg, every other day, 6 times) or doxorubicin plus GSK2795039 (2.5 mg/kg, twice a day, 9 weeks). Left ventricular (LV) total wall thickness and LV ejection fraction were decreased in doxorubicin-treated mice compared with saline-treated mice and the decreases were prevented by the treatment of the specific Nox2 inhibitor GSK2795039. The ratio of total heart weight to tibia length and myocyte cross-sectional area were decreased in doxorubicin-treated mice, and the decreases were attenuated by the GSK2795039 treatment. In doxorubicin-treated mice, myocardial Nox2 and 4-hydroxynonenal levels were increased, myocardial expression of GAP43, tyrosine hydroxylase and norepinephrine transporter, markers of sympathetic nerve terminals, was decreased, and these changes were prevented by the GSK2795039 treatment. The ratio of LC3 II/I, a marker of autophagy, and Atg5, Atg12 and Atg12-Atg5 conjugate proteins were increased in doxorubicin-treated mice, and the increases were attenuated by the GSK2795039 treatment. These findings suggest that inhibition of Nox2 by GSK2795039 attenuates cardiac sympathetic nerve terminal abnormalities and myocyte autophagy, thereby ameliorating cardiac atrophy and dysfunction after chronic doxorubicin treatment.

Assessment of the Impact of Carvedilol Administered Together with Dexrazoxan and Doxorubicin on Liver Structure and Function, Iron Metabolism, and Myocardial Redox System in Rats

Late cardiotoxicity is a formidable challenge in anthracycline-based anticancer treatments. Previous research hypothesized that co-administration of carvedilol (CVD) and dexrazoxane (DEX) might provide superior protection against doxorubicin (DOX)-induced cardiotoxicity compared to DEX alone. However, the anticipated benefits were not substantiated by the findings. This study focuses on investigating the impact of CVD on myocardial redox system parameters in rats treated with DOX + DEX, examining its influence on overall toxicity and iron metabolism. Additionally, considering the previously observed DOX-induced ascites, a seldom-discussed condition, the study explores the potential involvement of the liver in ascites development. Compounds were administered weekly for ten weeks, with a specific emphasis on comparing parameter changes between DOX + DEX + CVD and DOX + DEX groups. Evaluation included alterations in body weight, feed and water consumption, and analysis of NADPH2, NADP+, NADPH2/NADP+, lipid peroxidation, oxidized DNA, and mRNA for superoxide dismutase 2 and catalase expressions in cardiac muscle. The iron management panel included markers for iron, transferrin, and ferritin. Liver abnormalities were assessed through histological examinations, aspartate transaminase, alanine transaminase, and serum albumin level measurements. During weeks 11 and 21, reduced NADPH2 levels were observed in almost all examined groups. Co-administration of DEX and CVD negatively affected transferrin levels in DOX-treated rats but did not influence body weight changes. Ascites predominantly resulted from cardiac muscle dysfunction rather than liver-related effects. The study's findings, exploring the impact of DEX and CVD on DOX-induced cardiotoxicity, indicate a lack of scientific justification for advocating the combined use of these drugs at histological, biochemical, and molecular levels.

PFKFB3 in neovascular eye disease: unraveling mechanisms and exploring therapeutic strategies

BACKGROUND

Neovascular eye disease is characterized by pathological neovascularization, with clinical manifestations such as intraocular exudation, bleeding, and scar formation, ultimately leading to blindness in millions of individuals worldwide. Pathologic ocular angiogenesis often occurs in common fundus diseases including proliferative diabetic retinopathy (PDR), age-related macular degeneration (AMD), and retinopathy of prematurity (ROP). Anti-vascular endothelial growth factor (VEGF) targets the core pathology of ocular angiogenesis.

MAIN BODY

In recent years, therapies targeting metabolism to prevent angiogenesis have also rapidly developed, offering assistance to patients with a poor prognosis while receiving anti-VEGF therapy and reducing the side effects associated with long-term VEGF usage. Phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3), a key enzyme in targeted metabolism, has been shown to have great potential, with antiangiogenic effects and multiple protective effects in the treatment of neovascular eye disease. In this review, we summarize the mechanisms of common types of neovascular eye diseases; discuss the protective effect and potential mechanism of targeting PFKFB3, including the related inhibitors of PFKFB3; and look forward to the future exploration directions and therapeutic prospects of PFKFB3 in neovascular eye disease.

CONCLUSION

Neovascular eye disease, the most common and severely debilitating retinal disease, is largely incurable, necessitating the exploration of new treatment methods. PFKFB3 has been shown to possess various potential protective mechanisms in treating neovascular eye disease. With the development of several drugs targeting PFKFB3 and their gradual entry into clinical research, targeting PFKFB3-mediated glycolysis has emerged as a promising therapeutic approach for the future of neovascular eye disease.

Studies on the ameliorative potential of dietary supplemented different dose of selenium on doxorubicin-induced ovarian damage in rat

Doxorubicin (Dox) may induce loss of follicles, resulting in the depletion of ovarian reserve and consequent premature ovarian failure. Selenium (Se) is an oligoelement with fundamental biological features and is among the most common chemical inhibitor compounds. The present study describes the curative effects of dietary supplementation with different Se doses on Dox-induced ovarian damage in rats. In this study, 64 adult female Wistar rats were randomly separated into eight groups: Control group, Dox group (5 mg/kg intraperitoneal [i.p.]), low-dose Se (0.5 mg/kg i.p.), middle dose Se (1 mg/kg i.p.), high dose (Se 2 mg/kg i.p.), Dox + low-dose Se group (0.5 mg/kg i.p.), Dox + middle dose Se (1 mg/kg i.p.), and Dox + high-dose Se group (2 mg/kg i.p.). After the experiment, ovarian follicles were counted, and Antimüllerian hormone, interleukin 1 beta, tumor necrosis factor alpha, and caspase-3 expression were determined. Levels of malondialdehyde, superoxide dismutase, catalase, and glutathione peroxidase were biochemically measured in ovarian tissue. Dox caused ovarian injury, as evidenced by significant changes in ovarian markers, histological abnormalities, and the debilitation of antioxidant defense mechanisms. Furthermore, Dox therapy significantly changed the expression of inflammatory and apoptotic markers. Dox + 1 mg Se with various saturations was studied, and this study demonstrated both histopathological and follicular reserve and more protective features. 1 mg Se pretreatment improved Dox-induced ovarian toxicity through alleviating the antioxidant mechanism, decreasing inflammation and apoptosis, and restoring ovarian architecture. As a result, our findings indicate that 1 mg Se is a promising therapeutic agent for the prevention of ovarian damage associated with Dox.

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.

Empagliflozin treatment of cardiotoxicity: A comprehensive review of clinical, immunobiological, neuroimmune, and therapeutic implications

Cancer and cardiovascular disorders are known as the two main leading causes of mortality worldwide. Cardiotoxicity is a critical and common adverse effect of cancer-related chemotherapy. Chemotherapy-induced cardiotoxicity has been associated with various cancer treatments, such as anthracyclines, immune checkpoint inhibitors, and kinase inhibitors. Different methods have been reported for the management of chemotherapy-induced cardiotoxicity. In this regard, sodium-glucose cotransporter-2 inhibitors (SGLT2i), a class of antidiabetic agents, have recently been applied to manage heart failure patients. Further, SGLT2i drugs such as EMPA exert protective cardiac and systemic effects. Moreover, it can reduce inflammation through the mediation of major inflammatory components, such as Nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasomes, Adenosine 5'-monophosphate-activated protein kinase (AMPK), and c-Jun N-terminal kinase (JNK) pathways, Signal transducer and activator of transcription (STAT), and overall decreasing transcription of proinflammatory cytokines. The clinical outcome of EMPA administration is related to improving cardiovascular risk factors, including body weight, lipid profile, blood pressure, and arterial stiffness. Intriguingly, SGLT2 suppressors can regulate microglia-driven hyperinflammation affecting neurological and cardiovascular disorders. In this review, we discuss the protective effects of EMPA in chemotherapy-induced cardiotoxicity from molecular, immunological, and neuroimmunological aspects to preclinical and clinical outcomes.

Circulating Biomarkers for Monitoring Chemotherapy-Induced Cardiotoxicity in Children

Most commonly diagnosed cancer pathologies in the pediatric population comprise leukemias and cancers of the nervous system. The percentage of cancer survivors increased from approximatively 50% to 80% thanks to improvements in medical treatments and the introduction of new chemotherapies. However, as a consequence, heart disease has become the main cause of death in the children due to the cardiotoxicity induced by chemotherapy treatments. The use of different cardiovascular biomarkers, complementing data obtained from electrocardiogram, echocardiography cardiac imaging, and evaluation of clinical symptoms, is considered a routine in clinical diagnosis, prognosis, risk stratification, and differential diagnosis. Cardiac troponin and natriuretic peptides are the best-validated biomarkers broadly accepted in clinical practice for the diagnosis of acute coronary syndrome and heart failure, although many other biomarkers are used and several potential markers are currently under study and possibly will play a more prominent role in the future. Several studies have shown how the measurement of cardiac troponin (cTn) can be used for the early detection of heart damage in oncological patients treated with potentially cardiotoxic chemotherapeutic drugs. The advent of high sensitive methods (hs-cTnI or hs-cTnT) further improved the effectiveness of risk stratification and monitoring during treatment cycles.

Afzelin protects against doxorubicin-induced cardiotoxicity by promoting the AMPKα/SIRT1 signaling pathway

BACKGROUND

Doxorubicin (DOX), a chemotherapeutic drug, could relieve the progressions of various diseases. However, its clinical application is limited due to its cardiotoxicity. This study aimed to investigate the effects of afzelin (a flavonol glycoside found in Houttuynia cordata) on the cardiotoxicity induced by DOX.

METHODS

In ex-vivo, H9C2 cells were incubated with 20, 40, or 80 μM afzelin for 12 h, followed by the treatment with 1 μM DOX for 12 h. In vivo, C57BL/6 J mice were intraperitoneally injected with 4 mg/kg/day DOX on days 1, 7, and 14. Meanwhile, starting from day 1, mice were intragastrically administrated with 5 mg/kg/day or 10 mg/kg/day afzelin for 20 days. The cardiac function of mice was evaluated by detecting hemodynamic parameters using the M-mode echocardiography.

RESULTS

DOX decreased the cell survival rate, and elevated apoptotic rate, as well as induced the oxidative stress and mitochondrial dysfunction in H9C2 cells. All these changes were alleviated by afzelin treatment in a concentration-dependent manner. The results were further proven by the mitigation of cardiac injury in vivo, as evidenced by the elevation of fractional shortening, heart weight/tibia length, and the rate of the increase/decrease of left ventricular pressure in mice subjected to DOX-induced cardiotoxicity. Furthermore, afzelin upregulated the expression of p-AMP-activated protein kinase alpha (AMPKα) and sirtuin1 (SIRT1). Dorsomorphin (an AMPKα inhibitor) abrogated the anti-cardiotoxicity effects of afzelin in H9C2 cells induced by DOX.

CONCLUSION

Afzelin protected against DOX-induced cardiotoxicity by promoting the AMPKα/SIRT1 signaling pathway.

Poly (ADP-ribose) polymerase pathway inhibitor (Olaparib) upregulates SERCA2a expression and attenuates doxorubicin-induced cardiomyopathy in mice

The cardiotoxicity induced by doxorubicin is dose-dependent. The present study tested the potential cardioprotective effect of Poly ADP Ribose Polymerase (PARP) pathway inhibitor "olaparib" in a mouse model of doxorubicin-induced cardiomyopathy (DOX-CM). Seventy-two male BALB/c mice were randomized into six equal groups; control, DOX-CM, dexrazoxane-treated, and three olaparib-treated groups (5, 10, and 50 mg/kg/day). Cardiomyopathy was assessed by heart weight/Tibial length (HW/TL) ratio, cardiac fibrosis, oxidative stress, and electron microscope. Myocardial expression of SERCA2a mRNA and cleaved PARP-1 protein were also assessed. Similar to dexrazoxane, olaparib (10 mg/kg/day) significantly ameliorated oxidative stress, and preserved cardiac structure. It also suppressed myocardial PARP-1 protein expression and boosted SERCA2a mRNA expression. Olaparib (5 or 50 mg/kg/day) failed to show comparable effects. The current study detected the cardioprotective effect of olaparib at a dosage of 10 mg/kg/day. Also, the present study discovered a new cardioprotective mechanism of dexrazoxane by targeting PARP-1 in the heart.

Doxorubicin and other anthracyclines in cancers: Activity, chemoresistance and its overcoming

Anthracyclines have been important and effective treatments against a number of cancers since their discovery. However, their use in therapy has been complicated by severe side effects and toxicity that occur during or after treatment, including cardiotoxicity. The mode of action of anthracyclines is complex, with several mechanisms proposed. It is possible that their high toxicity is due to the large set of processes involved in anthracycline action. The development of resistance is a major barrier to successful treatment when using anthracyclines. This resistance is based on a series of mechanisms that have been studied and addressed in recent years. This work provides an overview of the anthracyclines used in cancer therapy. It discusses their mechanisms of activity, toxicity, and chemoresistance, as well as the approaches used to improve their activity, decrease their toxicity, and overcome resistance.

Cardiotoxicity of anti-cancer drugs: cellular mechanisms and clinical implications

Cardio-oncology is an emerging field that seeks to enhance quality of life and longevity of cancer survivors. It is pertinent for clinicians to understand the cellular mechanisms of prescribed therapies, as this contributes to robust understanding of complex treatments and off-target effects, improved communication with patients, and guides long term care with the goal to minimise or prevent cardiovascular complications. Our aim is to review the cellular mechanisms of cardiotoxicity involved in commonly used anti-cancer treatments and identify gaps in literature and strategies to mitigate cardiotoxicity effects and guide future research endeavours.

Hyperoside prevents doxorubicin-induced cardiotoxicity by inhibiting NOXs/ROS/NLRP3 inflammasome signaling pathway

Clinical application of doxorubicin (Dox) in cancer chemotherapy is limited by its cardiotoxicity. Present study aimed to demonstrate the effect and mechanism of hyperoside in Dox-induced cardiotoxicity. C57BL/6 mice were injected with 12 mg/kg of Dox, and 1 μM Dox was exposed to primary cardiomyocytes. Cardiac function was evaluated by echocardiographic and myocardial enzyme levels. Cardiomyocyts apoptosis was analyzed by TUNEL staining and flow cytometry. Network pharmacology and molecular docking were utilized to explore potential targets of hyperoside. Protein expressions were detected by western blot and enzyme activities were determined by colorimetry. Cardiac dysfunction and cardiomyocyte apoptosis induced by Dox were attenuated by hyperoside. Mechanism of hyperoside was mainly related to "oxidative stress" pathway. Hyperoside exhibited strong binding activities with nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOXs, the main source of ROS in cardiomyocytes) and cyclooxygenases (COXs). Experiments proved that hyperoside suppressed the ROS generation and the elevated activities of NOXs and COXs induced by Dox. Dox also triggered the activation of NLRP3 inflammasome, which was reversed by hyperoside. Hyperoside bound to NOXs and COXs, which prevents Dox-induced cardiotoxicity by inhibiting NOXs/ROS/NLRP3 inflammasome signaling pathway. Hyperoside holds promise as a therapeutic strategy for Dox-induced cardiotoxicity.

Myeloperoxidase is a critical mediator of anthracycline-induced cardiomyopathy

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

RGS7 balances acetylation/de-acetylation of p65 to control chemotherapy-dependent cardiac inflammation

Cardiotoxicity remains a major limitation in the clinical utility of anthracycline chemotherapeutics. Regulator of G-protein Signaling 7 (RGS7) and inflammatory markers are up-regulated in the hearts of patients with a history of chemotherapy particularly those with reduced left-ventricular function. RGS7 knockdown in either the murine myocardium or isolated murine ventricular cardiac myocytes (VCM) or cultured human VCM provided marked protection against doxorubicin-dependent oxidative stress, NF-κB activation, inflammatory cytokine production, and cell death. In exploring possible mechanisms causally linking RGS7 to pro-inflammatory signaling cascades, we found that RGS7 forms a complex with acetylase Tip60 and deacetylase sirtuin 1 (SIRT1) and controls the acetylation status of the p65 subunit of NF-κB. In VCM, the detrimental impact of RGS7 could be mitigated by inhibiting Tip60 or activating SIRT1, indicating that the ability of RGS7 to modulate cellular acetylation capacity is critical for its pro-inflammatory actions. Further, RGS7-driven, Tip60/SIRT1-dependent cytokines released from ventricular cardiac myocytes and transplanted onto cardiac fibroblasts increased oxidative stress, markers of transdifferentiation, and activity of extracellular matrix remodelers emphasizing the importance of the RGS7-Tip60-SIRT1 complex in paracrine signaling in the myocardium. Importantly, while RGS7 overexpression in heart resulted in sterile inflammation, fibrotic remodeling, and compromised left-ventricular function, activation of SIRT1 counteracted the detrimental impact of RGS7 in heart confirming that RGS7 increases acetylation of SIRT1 substrates and thereby drives cardiac dysfunction. Together, our data identify RGS7 as an amplifier of inflammatory signaling in heart and possible therapeutic target in chemotherapeutic drug-induced cardiotoxicity.

Cardiac RGS7 and RGS11 drive TGFβ1-dependent liver damage following chemotherapy exposure

Off target damage to vital organ systems is an unfortunate side effect of cancer chemotherapy and remains a major limitation to the use of these essential drugs in the clinic. Despite decades of research, the mechanisms conferring susceptibility to chemotherapy driven cardiotoxicity and hepatotoxicity remain unclear. In the livers of patients with a history of chemotherapy, we observed a twofold increase in expression of G protein regulator RGS7 and a corresponding decrease in fellow R7 family member RGS11. Knockdown of RGS7 via introduction of RGS7 shRNA via tail vein injection decreased doxorubicin-induced hepatic collagen and lipid deposition, glycogen accumulation, and elevations in ALT, AST, and triglycerides by approximately 50%. Surprisingly, a similar result could be achieved via introduction of RGS7 shRNA directly to the myocardium without impacting RGS7 levels in the liver directly. Indeed, doxorubicin-treated cardiomyocytes secrete the endocrine factors transforming growth factor β1 (TGFβ1) and TGFβ superfamily binding protein follistatin-related protein 1 (FSTL1). Importantly, RGS7 overexpression in the heart was sufficient to recapitulate the impacts of doxorubicin on the liver and inhibition of TGFβ1 signaling with the receptor blocker GW788388 ameliorated the effect of cardiac RGS7 overexpression on hepatic fibrosis, steatosis, oxidative stress, and cell death as well as the resultant elevation in liver enzymes. Together these data demonstrate that RGS7 controls both the release of TGFβ1 from the heart and the profibrotic and pro-oxidant actions of TGFβ1 in the liver and emphasize the functional significance of endocrine cardiokine signaling in the pathogenesis of chemotherapy drive multiorgan damage.

PDE10A Inactivation Prevents Doxorubicin-Induced Cardiotoxicity and Tumor Growth

BACKGROUND

Cyclic nucleotides play critical roles in cardiovascular biology and disease. PDE10A (phosphodiesterase 10A) is able to hydrolyze both cAMP and cGMP. PDE10A expression is induced in various human tumor cell lines, and PDE10A inhibition suppresses tumor cell growth. Chemotherapy drug such as doxorubicin (DOX) is widely used in chemotherapy. However, cardiotoxicity of DOX remains to be a serious clinical complication. In the current study, we aim to determine the role of PDE10A and the effect of PDE10A inhibition on cancer growth and cardiotoxicity induced by DOX.

METHODS

We used global PDE10A knockout (KO) mice and PDE10A inhibitor TP-10 to block PDE10A function. DOX-induced cardiotoxicity was evaluated in C57Bl/6J mice and nude mice with implanted ovarian cancer xenografts. Isolated adult mouse cardiomyocytes and a human ovarian cancer cell line were used for in vitro functional and mechanistic studies.

RESULTS

We found that PDE10A deficiency or inhibition alleviated DOX-induced myocardial atrophy, apoptosis, and dysfunction in C57Bl/6J mice. RNA sequencing study revealed a number of PDE10A-regulated signaling pathways involved in DOX-induced cardiotoxicity. PDE10A inhibition increased the death, decreased the proliferation, and potentiated the effect of DOX on various human cancer cells. Importantly, in nude mice with implanted ovarian cancer xenografts, PDE10A inhibition attenuated tumor growth while protecting DOX-induced cardiotoxicity. In isolated cardiomyocytes, PDE10A contributed to DOX-induced cardiomyocyte death via increasing Top2β (topoisomerase 2β) expression, mitochondrial dysfunction, and DNA damage by antagonizing cGMP/PKG (protein kinase G) signaling. PDE10A contributed to cardiomyocyte atrophy via potentiating FoxO3 (forkhead box O3) signaling via both cAMP/PKA (protein kinase A)- and cGMP/PKG-dependent signaling.

CONCLUSIONS

Taken together, our study elucidates a novel role for PDE10A in cardiotoxicity induced by DOX and cancer growth. Given that PDE10A has been already proven to be a safe drug target, PDE10A inhibition may represent a novel therapeutic strategy in cancer therapy, with effects preventing DOX-induced cardiotoxicity and simultaneously antagonizing cancer growth.

Fabrication of an Injectable Star-polylactide/Thiolated Hyaluronate Hydrogel as a Double Drug-Delivery System for Cancer Treatment

Unsatisfactory solid-tumor penetration or rapid metabolism of nanomaterials limits their therapeutic efficacy. Here, we designed an injectable thiolated hyaluronate (HA-SH) hydrogel as a stable drug-releasing platform for in situ tumor treatment. Biodegradable star-shaped polylactide (S-PLLA) was first synthesized and fabricated to porous microspheres to encapsulate hydrophobic curcumin (Cur@S-PLLA), which was then blended with hydrophilic doxorubicin (Dox) and the HA-SH precursor to form composite in situ formable hydrogels [Cur@S-PLLA/(Dox)HA-SH]. The results showed that adding the microspheres improved the performance of the hydrogel, such as decreasing the gelation time from 1080 s to 960 s and also the swelling ratio. The mechanical strength increased from 27 to 45 kPa. In addition, the double drug system guaranteed a sustained release of drugs, releasing Dox at the early stage, with the continuous later release of Cur after gel swelling or S-PLLA degradation to achieve long-lasting tumor suppression, which inhibits the survival of cancer cells. The inhibitory effects of the hydrogels on MCF-7 were studied. The cell activity in the double-loaded hydrogel was significantly lower than that of the control groups, and apparent dead cells appeared in 2 days and fewer living cells with time. Flow cytometry revealed that the Cur@S-PLLA/(Dox)HA-SH group had the highest apoptosis ratio of 86.60% at 12 h, and the drugs caused the cell cycle to be blocked in phase M to reduce cell division. In summary, the innovative release platform is expected to be used in long-lasting tumor suppression and provides more ideas for the design of drug carriers.

Mechanisms of trastuzumab induced cardiotoxicity - is exercise a potential treatment?

The use of the adjuvant therapeutic antibody trastuzumab in breast cancer is associated with a range of cardiotoxic side effects despite successfully reducing the severity of outcomes cancer patients,. The most common cardiac effect, a reduction in left ventricular ejection fraction (LVEF), is a known precursor to heart failure and often requires interruption of chemotherapy to avoid endangering patients further. An understanding of trastuzumab's cardiac-specific interactions is therefore critical in devising new methods to not only avoid permanent cardiac damage, but also prolong treatment time, and therefore effectiveness, for breast cancer patients. Increasingly, the use of exercise as a treatment has been indicated across the field of cardio-oncology due to encouraging evidence that it can protect against LVEF reductions and heart failure. This review explores the mechanisms of trastuzumab-mediated cardiotoxicity, as well as the physiological effects of exercise on the heart, in order to assess the suitability of exercise intervention for breast cancer patients on trastuzumab antibody-therapy. We furthermore draw comparison to existing evidence for exercise intervention as a cardioprotective treatment in doxorubicin-induced cardiotoxicity. Although preclinical evidence seems to support exercise-based approaches also in trastuzumab-cardiotoxicity, current clinical evidence is too limited to confidently recommend it as a treatment, largely owing to issues of adherence. Future studies should therefore examine how the variety and duration of exercise can be adjusted to improve treatment effectiveness at a more personalised level.

GSK2795039 prevents RIP1-RIP3-MLKL-mediated cardiomyocyte necroptosis in doxorubicin-induced heart failure through inhibition of NADPH oxidase-derived oxidative stress

Doxorubicin (DOX), which is widely used for the treatment of cancer, induces cardiomyopathy associated with NADPH oxidase-derived reactive oxygen species. GSK2795039 is a novel small molecular NADPH oxidase 2 (Nox2) inhibitor. In this study, we investigated whether GSK2795039 prevents receptor-interacting protein kinase 1 (RIP1)-RIP3-mixed lineage kinase domain-like protein (MLKL)-mediated cardiomyocyte necroptosis in DOX-induced heart failure through NADPH oxidase inhibition. Eight-week old mice were randomly divided into 4 groups: control, GSK2795039, DOX and DOX plus GSK2795039. H9C2 cardiomyocytes were treated with DOX and GSK2795039. In DOX-treated mice, the survival rate was reduced, left ventricular (LV) end-systolic dimension was increased and LV fractional shortening was decreased, and these alterations were attenuated by the GSK2795039 treatment. GSK2795039 inhibited not only myocardial NADPH oxidase subunit gp91phox (Nox2) protein, but also p22phox, p47phox and p67phox proteins and prevented oxidative stress 8-hydroxy-2'-deoxyguanosine levels in DOX-treated mice. RIP3 protein and phosphorylated RIP1 (p-RIP1), p-RIP3 and p-MLKL proteins, reflective of their respective kinase activities, markers of necroptosis, were markedly increased in DOX-treated mice, and the increases were prevented by GSK2795039. GSK2795039 prevented the increases in serum lactate dehydrogenase and myocardial fibrosis in DOX-treated mice. Similarly, in DOX-treated cardiomyocytes, GSK2795039 improved cell viability, attenuated apoptosis and necrosis and prevented the increases in p-RIP1, p-RIP3 and p-MLKL expression. In conclusion, GSK2795039 prevents RIP1-RIP3-MLKL-mediated cardiomyocyte necroptosis through inhibition of NADPH oxidase-derived oxidative stress, leading to the improvement of myocardial remodeling and function in DOX-induced heart failure. These findings suggest that GSK2795039 may have implications for the treatment of DOX-induced cardiomyopathy.

Molecular mechanisms of anthracycline induced cardiotoxicity: Zebrafish come into play

Anthracyclines are among the most potent chemotherapeutics; however, cardiotoxicity significantly restricts their use. Indeed, anthracycline-induced cardiotoxicity (AIC) fares among the worst types of cardiomyopathy, and may only slowly and partially respond to standard heart failure therapies including β-blockers and ACE inhibitors. No therapy specifically designed to treat anthracycline cardiomyopathy at present, and neither is it known if any such strategy could be developed. To address this gap and to elucidate the molecular basis of AIC with a therapeutic goal in mind, zebrafish has been introduced as an in vivo vertebrate model about a decade ago. Here, we first review our current understanding of the basic molecular and biochemical mechanisms of AIC, and then the contribution of zebrafish to the AIC field. We summarize the generation of embryonic zebrafish AIC models (eAIC) and their use for chemical screening and assessment of genetic modifiers, and then the generation of adult zebrafish AIC models (aAIC) and their use for discovering genetic modifiers via forward mutagenesis screening, deciphering spatial-temporal-specific mechanisms of modifier genes, and prioritizing therapeutic compounds via chemical genetic tools. Several therapeutic target genes and related therapies have emerged, including a retinoic acid (RA)-based therapy for the early phase of AIC and an autophagy-based therapy that, for the first time, is able to reverse cardiac dysfunction in the late phase of AIC. We conclude that zebrafish is becoming an important in vivo model that would accelerate both mechanistic studies and therapeutic development of AIC.

The beneficial role of exercise in preventing doxorubicin-induced cardiotoxicity

Doxorubicin is a highly effective chemotherapeutic agent widely used to treat a variety of cancers. However, the clinical application of doxorubicin is limited due to its adverse effects on several tissues. One of the most serious side effects of doxorubicin is cardiotoxicity, which results in life-threatening heart damage, leading to reduced cancer treatment success and survival rate. Doxorubicin-induced cardiotoxicity results from cellular toxicity, including increased oxidative stress, apoptosis, and activated proteolytic systems. Exercise training has emerged as a non-pharmacological intervention to prevent cardiotoxicity during and after chemotherapy. Exercise training stimulates numerous physiological adaptations in the heart that promote cardioprotective effects against doxorubicin-induced cardiotoxicity. Understanding the mechanisms responsible for exercise-induced cardioprotection is important to develop therapeutic approaches for cancer patients and survivors. In this report, we review the cardiotoxic effects of doxorubicin and discuss the current understanding of exercise-induced cardioprotection in hearts from doxorubicin-treated animals.

A RGS7-CaMKII complex drives myocyte-intrinsic and myocyte-extrinsic mechanisms of chemotherapy-induced cardiotoxicity

Dose-limiting cardiotoxicity remains a major limitation in the clinical use of cancer chemotherapeutics. Here, we describe a role for Regulator of G protein Signaling 7 (RGS7) in chemotherapy-dependent heart damage, the demonstration for a functional role of RGS7 outside of the nervous system and retina. Though expressed at low levels basally, we observed robust up-regulation of RGS7 in the human and murine myocardium following chemotherapy exposure. In ventricular cardiomyocytes (VCM), RGS7 forms a complex with Ca²⁺/calmodulin-dependent protein kinase (CaMKII) supported by key residues (K412 and P391) in the RGS domain of RGS7. In VCM treated with chemotherapeutic drugs, RGS7 facilitates CaMKII oxidation and phosphorylation and CaMKII-dependent oxidative stress, mitochondrial dysfunction, and apoptosis. Cardiac-specific RGS7 knockdown protected the heart against chemotherapy-dependent oxidative stress, fibrosis, and myocyte loss and improved left ventricular function in mice treated with doxorubicin. Conversely, RGS7 overexpression induced fibrosis, reactive oxygen species generation, and cell death in the murine myocardium that were mitigated following CaMKII inhibition. RGS7 also drives production and release of the cardiokine neuregulin-1, which facilitates paracrine communication between VCM and neighboring vascular endothelial cells (EC), a maladaptive mechanism contributing to VCM dysfunction in the failing heart. Importantly, while RGS7 was both necessary and sufficient to facilitate chemotherapy-dependent cytotoxicity in VCM, RGS7 is dispensable for the cancer-killing actions of these same drugs. These selective myocyte-intrinsic and myocyte-extrinsic actions of RGS7 in heart identify RGS7 as an attractive therapeutic target in the mitigation of chemotherapy-driven cardiotoxicity.

Plasma advanced oxidation products as an additional tool in assessment of post-infarction heart failure

OBJECTIVE

To define which oxidative stress markers could be used as diagnostic tools in the assessment of post-infarction heart failure (HF).

METHODS

This observational study enrolled patients with HF that were divided into three subgroups (ejection fraction [EF] ≥ 50%; EF 40-49%; EF < 40%) and age- and sex-matched healthy control subjects. The plasma concentrations of advanced oxidation protein products (AOPP), thiobarbituric acid reactive substances, catalase activity and free thiols were determined in all participants.

RESULTS

The study enrolled 81 patients with HF and 68 healthy control subjects. There were significant differences in the values ​​of oxidative stress markers between patients and controls. Oxidative stress parameters did not differ between the subgroups of patients, except for AOPP, which was significantly higher in the EF < 40% group. Univariate and multivariate logistic regression analyses showed an association between AOPP and HF in the EF ≥ 50% group, while receiver operating characteristic (ROC) curve analysis identified a cut-off value of 60.89 µmol/l for AOPP.

CONCLUSIONS

Based on the ROC curve analysis of AOPP and the higher significance in the multivariate analyses for patients with EF ≥ 50%, these current results suggest that AOPP could be a useful additional tool in the assessment of post-infarction HF.

Lung Pneumonitis and Fibrosis in Cancer Therapy: A Review on Cellular and Molecular Mechanisms

Fibrosis and pneumonitis are the most important side effects of lung tissue following cancer therapy. Radiotherapy and chemotherapy by some drugs, such as bleomycin, can induce pneumonitis and fibrosis. Targeted therapy and immunotherapy also may induce pneumonitis and fibrosis to a lesser extent compared to chemotherapy and radiotherapy. Activation of lymphocytes by immunotherapy or infiltration of inflammatory cells such as macrophages, lymphocytes, neutrophils, and mast cells following chemo/radiation therapy can induce pneumonitis. Furthermore, the polarization of macrophages toward M2 cells and the release of anti-inflammatory cytokines stimulate fibrosis. Lung fibrosis and pneumonitis may also be potentiated by some other changes such as epithelial-mesenchymal transition (EMT), oxidative stress, reduction/oxidation (redox) responses, renin-angiotensin system, and the upregulation of some inflammatory mediators such as a nuclear factor of kappa B (NF-κB), inflammasome, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS). Damages to the lung vascular system and the induction of hypoxia also can induce pulmonary injury following chemo/radiation therapy. This review explains various mechanisms of the induction of pneumonitis and lung fibrosis following cancer therapy. Furthermore, the targets and promising agents to mitigate lung fibrosis and pneumonitis will be discussed.

Does Myocardial Atrophy Represent Anti-Arrhythmic Phenotype?

This review focuses on cardiac atrophy resulting from mechanical or metabolic unloading due to various conditions, describing some mechanisms and discussing possible strategies or interventions to prevent, attenuate or reverse myocardial atrophy. An improved awareness of these conditions and an increased focus on the identification of mechanisms and therapeutic targets may facilitate the development of the effective treatment or reversion for cardiac atrophy. It appears that a decrement in the left ventricular mass itself may be the central component in cardiac deconditioning, which avoids the occurrence of life-threatening arrhythmias. The depressed myocardial contractility of atrophied myocardium along with the upregulation of electrical coupling protein, connexin43, the maintenance of its topology, and enhanced PKCƐ signalling may be involved in the anti-arrhythmic phenotype. Meanwhile, persistent myocardial atrophy accompanied by oxidative stress and inflammation, as well as extracellular matrix fibrosis, may lead to severe cardiac dysfunction, and heart failure. Data in the literature suggest that the prevention of heart failure via the attenuation or reversion of myocardial atrophy is possible, although this requires further research.

RGS11-CaMKII complex mediated redox control attenuates chemotherapy-induced cardiac fibrosis

Dose limiting cardiotoxicity remains a major limiting factor in the clinical use of several cancer chemotherapeutics including anthracyclines and the antimetabolite 5-fluorouracil (5-FU). Prior work has demonstrated that chemotherapeutics increase expression of R7 family regulator of G protein signaling (RGS) protein-binding partner Gβ5, which drives myocyte cytotoxicity. However, though several R7 family members are expressed in heart, the exact role of each protein in chemotherapy driven heart damage remains unclear. Here, we demonstrate that RGS11, downregulated in the human heart following chemotherapy exposure, possesses potent anti-apoptotic actions, in direct opposition to the actions of fellow R7 family member RGS6. RGS11 forms a direct complex with the apoptotic kinase CaMKII and stress responsive transcription factor ATF3 and acts to counterbalance the ability of CaMKII and ATF3 to trigger oxidative stress, mitochondrial dysfunction, cell death, and release of the cardiokine neuregulin-1 (NRG1), which mediates pathological intercommunication between myocytes and endothelial cells. Doxorubicin triggers RGS11 depletion in the murine myocardium, and cardiac-specific OE of RGS11 decreases doxorubicin-induced fibrosis, myocyte hypertrophy, apoptosis, oxidative stress, and cell loss and aids in the maintenance of left ventricular function. Conversely, RGS11 knockdown in heart promotes cardiac fibrosis associated with CaMKII activation and ATF3/NRG1 induction. Indeed, inhibition of CaMKII largely prevents the fibrotic remodeling resulting from cardiac RGS11 depletion underscoring the functional importance of the RGS11-CaMKII interaction in the pathogenesis of cardiac fibrosis. These data describe an entirely new role for RGS11 in heart and identify RGS11 as a potential new target for amelioration of chemotherapy-induced cardiotoxicity.

NADPH Oxidases in Diastolic Dysfunction and Heart Failure with Preserved Ejection Fraction

Nicotinamide adenine dinucleotide phosphate (NADPH) oxidases regulate production of reactive oxygen species (ROS) that cause oxidative damage to cellular components but also regulate redox signaling in many cell types with essential functions in the cardiovascular system. Research over the past couple of decades has uncovered mechanisms by which NADPH oxidase (NOX) enzymes regulate oxidative stress and compartmentalize intracellular signaling in endothelial cells, smooth muscle cells, macrophages, cardiomyocytes, fibroblasts, and other cell types. NOX2 and NOX4, for example, regulate distinct redox signaling mechanisms in cardiac myocytes pertinent to the onset and progression of cardiac hypertrophy and heart failure. Heart failure with preserved ejection fraction (HFpEF), which accounts for at least half of all heart failure cases and has few effective treatments to date, is classically associated with ventricular diastolic dysfunction, i.e., defects in ventricular relaxation and/or filling. However, HFpEF afflicts multiple organ systems and is associated with systemic pathologies including inflammation, oxidative stress, arterial stiffening, cardiac fibrosis, and renal, adipose tissue, and skeletal muscle dysfunction. Basic science studies and clinical data suggest a role for systemic and myocardial oxidative stress in HFpEF, and evidence from animal models demonstrates the critical functions of NOX enzymes in diastolic function and several HFpEF-associated comorbidities. Here, we discuss the roles of NOX enzymes in cardiovascular cells that are pertinent to the development and progression of diastolic dysfunction and HFpEF and outline potential clinical implications.

Understanding the Protective Role of Exosomes in Doxorubicin-Induced Cardiotoxicity

Doxorubicin (DOX) is a class of effective chemotherapeutic agents widely used in clinical practice. However, its use has been limited by cardiotoxicity. The mechanism of DOX-induced cardiotoxicity (DIC) is complex, involving oxidative stress, Ca²⁺ overload, inflammation, pyroptosis, ferroptosis, apoptosis, senescence, etc. Exosomes (EXOs), as extracellular vesicles (EVs), play an important role in the material exchange and signal transmission between cells by carrying components such as proteins and RNAs. More recently, there has been a growing number of publications focusing on the protective effect of EXOs on DIC. Here, this review summarized the main mechanisms of DIC, discussed the mechanism of EXOs in the treatment of DIC, and further explored the value of EXOs as diagnostic biomarkers and therapeutic strategies for DIC.

Liposomes embedded with PEGylated iron oxide nanoparticles enable ferroptosis and combination therapy in cancer

Ferroptosis, an iron-dependent regulated cell death process driven by excessive lipid peroxides, can enhance cancer vulnerability to chemotherapy, targeted therapy and immunotherapy. As an essential upstream process for ferroptosis activation, lipid peroxidation of biological membranes is expected to be primarily induced by intrabilayer reactive oxygen species (ROS), indicating a promising strategy to initiate peroxidation by improving the local content of diffusion-limited ROS in the lipid bilayer. Herein, liposomes embedded with PEG-coated 3 nm γ-Fe₂O₃ nanoparticles in the bilayer (abbreviated as Lp-IO) were constructed to promote the intrabilayer generation of hydroxyl radicals (•OH) from hydrogen peroxide (H₂O₂), and the integration of amphiphilic PEG moieties with liposomal bilayer improved lipid membrane permeability to H₂O₂ and •OH, resulting in efficient initiation of lipid peroxidation and thus ferroptosis in cancer cells. Additionally, Lp-IO enabled traceable magnetic resonance imaging and pH/ROS dual-responsive drug delivery. Synergistic antineoplastic effects of chemotherapy and ferroptosis, and alleviated chemotherapeutic toxicity, were achieved by delivering doxorubicin (capable of xCT and glutathione peroxidase inhibition) with Lp-IO. This work provides an efficient alternative for triggering therapeutic lipid peroxidation and a ferroptosis-activating drug delivery vehicle for combination cancer therapies.

Genetic Susceptibility and Mechanisms Underlying the Pathogenesis of Anthracycline-Associated Cardiotoxicity

Anthracyclines are chemotherapeutic agents widely used to treat a variety of cancers, and these drugs have revolutionized our management of cancer patients. The dose-dependent cardiotoxicity of anthracyclines, however, remains one of the leading causes of chemotherapy treatment-associated mortality in cancer survivors. Patient threshold doses leading to anthracycline-induced cardiotoxicity (AIC) are highly variable among affected patients. This variability is largely ascribed to genetic variants in individuals' genomes. Here, we briefly discuss the prevailing mechanisms underlying the pathogenesis of AIC, and then, we review the genetic variants, mostly identified through human genetic approaches and identified in cancer survivors. The identification of all genetic susceptibilities and elucidation of underlying mechanisms of AIC can help improve upfront risk prediction assessment for potentially severe cardiotoxicity disease and provide valuable insights into the understanding of AIC pathophysiology, which can be further leveraged to develop targeted pharmacogenetic therapies for those at high risk.

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

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

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

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

Understanding Anthracycline Cardiotoxicity From Mitochondrial Aspect

Anthracyclines, such as doxorubicin, represent one group of chemotherapy drugs with the most cardiotoxicity. Despite that anthracyclines are capable of treating assorted solid tumors and hematological malignancies, the side effect of inducing cardiac dysfunction has hampered their clinical use. Currently, the mechanism underlying anthracycline cardiotoxicity remains obscure. Increasing evidence points to mitochondria, the energy factory of cardiomyocytes, as a major target of anthracyclines. In this review, we will summarize recent findings about mitochondrial mechanism during anthracycline cardiotoxicity. In particular, we will focus on the following aspects: 1) the traditional view about anthracycline-induced reactive oxygen species (ROS), which is produced by mitochondria, but in turn causes mitochondrial injury. 2) Mitochondrial iron-overload and ferroptosis during anthracycline cardiotoxicity. 3) Autophagy, mitophagy and mitochondrial dynamics during anthracycline cardiotoxicity. 4) Anthracycline-induced disruption of cardiac metabolism.

Cardiomyocyte Atrophy, an Underestimated Contributor in Doxorubicin-Induced Cardiotoxicity

Left ventricular (LV) mass loss is prevalent in doxorubicin (DOX)-induced cardiotoxicity and is responsible for the progressive decline of cardiac function. Comparing with the well-studied role of cell death, the part of cardiomyocyte atrophy (CMA) playing in the LV mass loss is underestimated and the knowledge of the underlying mechanism is still limited. In this review, we summarized the recent advances in the DOX-induced CMA. We found that the CMA caused by DOX is associated with the upregulation of FOXOs and “atrogenes,” the activation of transient receptor potential canonical 3-NADPH oxidase 2 (TRPC3-Nox2) axis, and the suppression of IGF-1-PI3K signaling pathway. The imbalance of anabolic and catabolic process may be the common final pathway of these mechanisms. At last, we provided some strategies that have been demonstrated to alleviate the DOX-induced CMA in animal models.

Protective effects of necrostatin-1 on doxorubicin-induced cardiotoxicity in rat heart

Background: Doxorubicin (Dox) is one of the most effective antineoplastic drugs which has severe cardiotoxic effects, limiting its clinical usage. Though the exact mechanism of doxorubicin-induced cardiotoxicity is yet to be elucidated, it is shown that production of reactive oxygen species (ROS) increases oxidative stress and leads to cardiomyocyte apoptosis and necroptosis which is also defined as a programmed cell death.Purpose: In the present study, we investigate the effects of necrostatin-1 (Nec-1)-an inhibitor of receptor interaction proteins 1 (RIP1) and necroptosis-on doxorubicin-induced cardiotoxicity in rats.Research Design: Hearts were isolated and perfused by the Langendorff system in all four groups. Perfusion pressure (PP), left ventricular developed pressure (LVDP) and heart rate per minute (HR), LV (dP/dt) max, and LV (dP/dt) min which shows cardiac contractility and relaxation were recorded.Results: Results showed that PP significantly increased with Dox treatment and significantly decreased with Nec-1 treatment, while HR, LVDP, LV (dP/dt) max, and LV (dP/dt) min values significantly decreased with the Dox-treated group and significantly increased with Nec-1 treatment. Also with Nec-1 treatment, gene expression levels of anti-apoptotic Bcl-2 significantly increased and pro-apoptotic protein Bax, apoptotic marker caspase-3, and Nox-2 significantly decreased compared to the Dox-treated group. In heart tissues, MDA levels were significantly increased with Dox and decreased with Nec-1 treatment. These results were supported by the histological analysis indicated that Nec-1 reduced doxorubicin-induced cellular injury.Conclusions: In conclusion, our data indicate that Nec-1 ameliorates doxorubicin-induced cardiotoxicity by reducing oxidative stress injury and attenuating apoptosis and necroptosis.

Resolvin D1 Attenuates Doxorubicin-Induced Cardiotoxicity by Inhibiting Inflammation, Oxidative and Endoplasmic Reticulum Stress

Resolvin D1 (RvD1) is a lipid mediator that promotes resolution of inflammation. However, the function of RvD1 in doxorubicin- (Dox-) induced cardiotoxicity remains to be clarified. This study aimed to investigate whether RvD1 could attenuate Dox-induced cardiac injury. The mice were divided into three groups: control, Dox (20 mg/kg, once, intraperitoneally), and Dox + RvD1. RvD1 (2.5 μg/kg, intraperitoneally) was injected daily for 5 days. Echocardiography was performed to evaluate the cardiac function, and the heart tissue and serum samples were collected for further analyses. The results showed that RvD1 attenuated the decreased ratio of heart weight/body weight and heart weight/tibia length, the increased level of creatine kinase and activity of lactate dehydrogenase after Dox treatment. RvD1 improved the ejection fraction and fractional shortening of left ventricular and attenuated the severity of apoptosis induced by Dox. As for the underlying pathways, the results showed that RvD1 reduced the expression of IL-1 and IL-6, and attenuated the phosphorylation of P65 in cardiac tissue. RvD1 attenuated the oxidative stress induced by Dox, as demonstrated by the attenuated levels of superoxide dismutase, glutathione, and malondialdehyde, decreased expression of Nox-2 and Nox-4 and increased expression of Nrf-2 and HO-1. In addition, RvD1 also inhibited the endoplasmic reticulum stress induced by Dox. These results indicate the potential therapeutic benefits of RvD1 in Dox-induced cardiotoxicity in mice, and the mechanism may be related to the attenuated inflammation, oxidative stress and endoplasmic reticulum stress.

Novel Mechanisms of Anthracycline-Induced Cardiovascular Toxicity: A Focus on Thrombosis, Cardiac Atrophy, and Programmed Cell Death

Anthracycline antineoplastic agents such as doxorubicin are widely used and highly effective component of adjuvant chemotherapy for breast cancer and curative regimens for lymphomas, leukemias, and sarcomas. The primary dose-limiting adverse effect of anthracyclines is cardiotoxicity that typically manifests as cardiomyopathy and can progress to the potentially fatal clinical syndrome of heart failure. Decades of pre-clinical research have explicated the complex and multifaceted mechanisms of anthracycline-induced cardiotoxicity. It is well-established that oxidative stress contributes to the pathobiology and recent work has elucidated important central roles for direct mitochondrial injury and iron overload. Here we focus instead on emerging aspects of anthracycline-induced cardiotoxicity that may have received less attention in other recent reviews: thrombosis, myocardial atrophy, and non-apoptotic programmed cell death.

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

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

Cardiac inflammation and fibrosis following chemo/radiation therapy: mechanisms and therapeutic agents

The incidence of cardiovascular disorders is one of the most concerns among people who underwent cancer therapy. The heart side effects of cancer therapy may occur during treatment to some years after the end of treatment. Some epidemiological studies confirm that heart diseases are one of the most common reasons for mortality among patients that were received treatment for cancer. Experimental studies and also clinical investigations indicate that inflammatory changes such as pericarditis, myocarditis, and also fibrosis are key mechanisms of cardiac diseases following chemotherapy/radiotherapy. It seems that chronic oxidative stress, massive cell death, and chronic overproduction of pro-inflammatory and pro-fibrosis cytokines are the key mechanisms of cardiovascular diseases following cancer therapy. Furthermore, infiltration of inflammatory cells and upregulation of some enzymes such as NADPH Oxidases are a hallmark of heart diseases after cancer therapy. In the current review, we aim to explain how radiation or chemotherapy can induce inflammatory and fibrosis-related diseases in the heart. We will explain the cellular and molecular mechanisms of cardiac inflammation and fibrosis following chemo/radiation therapy, and then review some adjuvants to reduce the risk of inflammation and fibrosis in the heart.

Microbiota modulate Doxorubicin induced cardiotoxicity

Chemotherapy has several adverse effects to patients, some of which are life-threatening. We hypothesized that Doxorubicin induced microbiome imbalance and intestinal damage may contribute to Doxorubicin induced cardiac dysfunction. Male adult (2-3 months) C57BL/6 mice were administered 3 mg/kg, 5 mg/kg, 7.5 mg/kg,15 mg/kg, 20 mg/kg doses of Doxorubicin. Echocardiography was performed at 7 and 14 days after Doxorubicin administration. 16S rRNA amplicon sequencing was used to characterize microbiome changes. Fecal microbiota transplantation (FMT) was performed to evaluate the role of the microbiota on Doxorubicin induced cardiac dysfunction. Doxorubicin dose dependently increases mortality rate and induces cardiac dysfunction. 5 mg/kg-Doxorubicin significantly induces decreased left ventricular ejection fraction (LVEF) and fraction shortening (FS) as well as increased cardiac fibrosis, inflammation and oxidative stress respond without increasing mortality. 5 mg/kg-Doxorubicin induces significant decreased colorectum length, increased loss of goblet cells, numbers of ulcers and infiltration of lymphocyte clusters and decreased tight junction protein ZO-1, as well as increased plasma endotoxin level measured by ELISA assay. 16S rRNA microbiota analysis shows that Doxorubicin-induced microbiota dysbiosis with decreased community richness compared with normal control mice. FMT to Doxorubicin-5 mg treated mice significantly improved cardiac function by increasing LVEF and FS as well as decreased perivascular and interstitial fibrosis; increased colorectum length, decreased the loss of goblet cells,infiltration of lymphocyte clusters,the number of ulcers and plasma endotoxin level; improved microbiota composition, function and diversity with increased abundance of Alloprevotella, Prevotellaceae_UCG-001 and Rikenellaceae_RC9_gut_group. We find that normal fecal transplantation improves cardiac function, decreases gut damage and alter microbiota composition induced by Doxorubicin. The microbiota appears to contribute to heart-gut interaction.

Pediatric Chemotherapy Drugs Associated With Cardiotoxicity

Pediatric cancers are a common cause of childhood morbidity. As a result, chemotherapeutic regimens have been designed to target childhood cancers. These medications are necessary to treat pediatric cancers, however, oncology management options are accompanied by multiple negative and potentially fatal adverse effects. Although anthracyclines are the most commonly used chemotherapeutic agents associated with cardiotoxicity, we also explore other chemotherapeutic drugs used in children that can potentially affect the heart. Genetic variations resulting in single nucleotide polymorphism (SNP) have the propensity to modify the cardiotoxic effects of the chemotherapy drugs. The clinical presentation of the cardiac effects can vary from arrhythmias and heart failure to completely asymptomatic. A range of imaging studies and laboratory investigations can protect the heart from severe outcomes. The physiology of the heart and the effect of drugs in children vary vividly from adults; therefore, it is crucial to study the cardiotoxic effect of chemotherapy drugs in the pediatric population. This review highlights the potential contributing factors for cardiotoxicity in the pediatric population and discusses the identification and management options.

Cardiotoxicity of Antineoplastic Therapies and Applications of Induced Pluripotent Stem Cell-Derived Cardiomyocytes

The therapeutic landscape for the treatment of cancer has evolved significantly in recent decades, aided by the development of effective oncology drugs. However, many cancer drugs are often poorly tolerated by the body and in particular the cardiovascular system, causing adverse and sometimes fatal side effects that negate the chemotherapeutic benefits. The prevalence and severity of chemotherapy-induced cardiotoxicity warrants a deeper investigation of the mechanisms and implicating factors in this phenomenon, and a consolidation of scientific efforts to develop mitigating strategies. Aiding these efforts is the emergence of induced pluripotent stem cells (iPSCs) in recent years, which has allowed for the generation of iPSC-derived cardiomyocytes (iPSC-CMs): a human-based, patient-derived, and genetically variable platform that can be applied to the study of chemotherapy-induced cardiotoxicity and beyond. After surveying chemotherapy-induced cardiotoxicity and the associated chemotherapeutic agents, we discuss the use of iPSC-CMs in cardiotoxicity modeling, drug screening, and other potential applications. Improvements to the iPSC-CM platform, such as the development of more adult-like cardiomyocytes and ongoing advances in biotechnology, will only enhance the utility of iPSC-CMs in both basic science and clinical applications.

Cardiac Dysfunction in a Mouse Vascular Dementia Model of Bilateral Common Carotid Artery Stenosis

Background: Cardiac function is associated with cognitive function. Previously, we found that stroke and traumatic brain injury evoke cardiac dysfunction in mice. In this study, we investigate whether bilateral common carotid artery stenosis (BCAS), a model that induces vascular dementia (VaD) in mice, induces cardiac dysfunction. Methods: Late-adult (6-8 months) C57BL/6J mice were subjected to sham surgery (n = 6) or BCAS (n = 8). BCAS was performed by applying microcoils (0.16 mm internal diameter) around both common carotid arteries. Cerebral blood flow and cognitive function tests were performed 21-28 days post-BCAS. Echocardiography was conducted in conscious mice 29 days after BCAS. Mice were sacrificed 30 days after BCAS. Heart tissues were isolated for immunohistochemical evaluation and real-time PCR assay. Results: Compared to sham mice, BCAS in mice significantly induced cerebral hypoperfusion and cognitive dysfunction, increased cardiac hypertrophy, as indicated by the increased heart weight and the ratio of heart weight/body weight, and induced cardiac dysfunction and left ventricular (LV) enlargement, indicated by a decreased LV ejection fraction (LVEF) and LV fractional shortening (LVFS), increased LV dimension (LVD), and increased LV mass. Cognitive deficits significantly correlated with cardiac deficits. BCAS mice also exhibited significantly increased cardiac fibrosis, increased oxidative stress, as indicated by 4-hydroxynonenal and NADPH oxidase-2, increased leukocyte and macrophage infiltration into the heart, and increased cardiac interleukin-6 and thrombin gene expression. Conclusions: BCAS in mice without primary cardiac disease provokes cardiac dysfunction, which, in part, may be mediated by increased inflammation and oxidative stress.

Redox interactions-induced cardiac toxicity in cancer therapy

Cancer patients undergoing radiotherapy, chemotherapy, or targeted cancer therapy are exposed to the risk of several side effects because of the heavy production of ROS by ionizing radiation or some chemotherapy drugs. Damages to DNA, mitochondria, membrane and other organelles within normal tissue cells such as cardiomyocytes and endothelial cells lead to the release of some toxins which are associated with triggering inflammatory cells to release several types of cytokines, chemokines, ROS, and RNS. The release of some molecules following radiotherapy or chemotherapy stimulates reduction/oxidation (redox) reactions. Redox reactions cause remarkable changes in the level of reactive oxygen species (ROS) and reactive nitrogen species (RNS). Excessive production of ROS and RNS or suppression of antioxidant defense enzymes leads to damage to critical macromolecules, which may continue for long times. Increased levels of some cytokines and oxidative injury are hallmarks of heart injury following cancer therapy. Redox reactions may be involved in several heart disorders such as fibrosis, cardiomyopathy, and endothelium injury. In the current review, we explain the cellular and molecular mechanisms of redox interactions following radiotherapy, chemotherapy, and targeted cancer therapy. Afterward, we explain the evidence of the involvement of redox reactions in heart diseases.

Molecular mechanisms of anthracycline cardiovascular toxicity

Anthracyclines are effective chemotherapeutic agents, commonly used in the treatment of a variety of hematologic malignancies and solid tumors. However, their use is associated with a significant risk of cardiovascular toxicities and may result in cardiomyopathy and heart failure. Cardiomyocyte toxicity occurs via multiple molecular mechanisms, including topoisomerase II-mediated DNA double-strand breaks and reactive oxygen species (ROS) formation via effects on the mitochondrial electron transport chain, NADPH oxidases (NOXs), and nitric oxide synthases (NOSs). Excess ROS may cause mitochondrial dysfunction, endoplasmic reticulum stress, calcium release, and DNA damage, which may result in cardiomyocyte dysfunction or cell death. These pathophysiologic mechanisms cause tissue-level manifestations, including characteristic histopathologic changes (myocyte vacuolization, myofibrillar loss, and cell death), atrophy and fibrosis, and organ-level manifestations including cardiac contractile dysfunction and vascular dysfunction. In addition, these mechanisms are relevant to current and emerging strategies to diagnose, prevent, and treat anthracycline-induced cardiomyopathy. This review details the established and emerging data regarding the molecular mechanisms of anthracycline-induced cardiovascular toxicity.

Doxorubicin-induced cardiotoxicity: An update on the molecular mechanism and novel therapeutic strategies for effective management

Doxorubicin (Dox) is a secondary metabolite of the mutated strain of Streptomyces peucetius var. Caesius and belongs to the anthracyclines family. The anti-cancer activity of Dox is mainly exerted through the DNA intercalation and inhibiting topoisomerase II enzyme in fast-proliferating tumors. However, Dox causes cumulative and dose-dependent cardiotoxicity, which results in increased risks of mortality among cancer patients and thus limiting its wide clinical applications. There are several mechanisms has been proposed for doxorubicin-induced cardiotoxicity and oxidative stress, free radical generation and apoptosis are most widely reported. Apart from this, other mechanisms are also involved in Dox-induced cardiotoxicity such as impaired mitochondrial function, a perturbation in iron regulatory protein, disruption of Ca²⁺ homeostasis, autophagy, the release of nitric oxide and inflammatory mediators and altered gene and protein expression that involved apoptosis. Dox also causes downregulation of DNA methyltransferase 1 (DNMT1) enzyme activity which leads to a reduction in the DNA methylation process. This hypomethylation causes dysregulation in the mitochondrial genes like peroxisome proliferator-activated receptor-gamma coactivator (PGC)-1-alpha (PGC-1α), nuclear respiratory factor 1 (NRF-1) and mitochondrial transcription factor A (TFAM) unit in the heart. Apart from DNA methylation, Dox treatment also alters the micro RNAs levels and histone deacetylase (HDAC) activity. Therefore, in the current review, we have provided a detailed update on the current understanding of the pathological mechanisms behind the well-known Dox-induced cardiotoxicity. Further, we have provided some of the most plausible pharmacological strategies which have been tested against Dox-induced cardiotoxicity.

SNX17 protects the heart from doxorubicin-induced cardiotoxicity by modulating LMOD2 degradation

Anthracyclines including doxorubicin (DOX) are still the most widely used and efficacious antitumor drugs, although their cardiotoxicity is a significant cause of heart failure. Despite considerable efforts being made to minimize anthracycline-induced cardiac adverse effects, little progress has been achieved. In this study, we aimed to explore the role and underlying mechanism of SNX17 in DOX-induced cardiotoxicity. We found that SNX17 was downregulated in cardiomyocytes treated with DOX both in vitro and in vivo. DOX treatment combined with SNX17 interference worsened the damage to neonatal rat ventricular myocytes (NRVMs). Furthermore, the rats with SNX17 deficiency manifested increased susceptibility to DOX-induced cardiotoxicity (myocardial damage and fibrosis, impaired contractility and cardiac death). Mechanistic investigation revealed that SNX17 interacted with leiomodin-2 (LMOD2), a key regulator of the thin filament length in muscles, via its C-TERM domain and SNX17 deficiency exacerbated DOX-induced cardiac systolic dysfunction by promoting aberrant LMOD2 degradation through lysosomal pathway. In conclusion, these findings highlight that SNX17 plays a protective role in DOX-induced cardiotoxicity, which provides an attractive target for the prevention and treatment of anthracycline induced cardiotoxicity.

The Utility of Intraventricular Pressure Gradient for Early Detection of Chemotherapy-Induced Subclinical Cardiac Dysfunction in Dogs

Early detection of doxorubicin (DXR)-induced cardiomyopathy (DXR-ICM) is crucial to improve cancer patient outcomes and survival. In recent years, the intraventricular pressure gradient (IVPG) has been a breakthrough as a sensitive index to assess cardiac function. This study aimed to evaluate the usefulness of IVPG for the early detection of chemotherapy-related cardiac dysfunction. For this purpose, six dogs underwent conventional, speckle tracking, and color M-mode echocardiography concomitantly with pressure-and-volume analysis by conductance catheter. The cardiac function measurements were assessed before DXR administration (baseline, Pre), at the end of treatment protocol (Post), and at 1.5 years follow-up (Post2). The result showed a significant reduction in the left ventricular end-systolic pressure-volume (Emax: 4.4 ± 0.7, 6.1 ± 1.6 vs. 8.4 ± 0.8 mmHg/mL), total-IVPG (0.59 ± 0.12, 0.62 ± 0.15 vs. 0.86 ± 0.12 mmHg), and mid-IVPG (0.28 ± 0.12, 0.31 ± 0.11 vs. 0.48 ± 0.08 mmHg), respectively in Post2 and Post compared with the baseline (p < 0.05). Mid-to-apical IVPG was also reduced in Post2 compared with the baseline (0.29 ± 0.13 vs. 0.51 ± 0.11). Meanwhile, the fraction shortening, ejection fraction, and longitudinal strain revealed no change between groups. Total and mid-IVPG were significantly correlated with Emax (R = 0.49; p < 0.05, both) but only mid-IVPG was a predictor for Emax (R2 = 0.238, p = 0.040). In conclusion, this study revealed that impairment of contractility was the initial changes observed with DXR-ICM in dogs and only IVPG could noninvasively detect subclinical alterations in cardiac function. Color M-mode echocardiography-derived IVPG could be a potential marker for the early detection of doxorubicin cardiomyopathy.