Early transcriptional changes in cardiac mitochondria during chronic doxorubicin exposure and mitigation by dexrazoxane in mice

The Distant Molecular Effects on the Brain by Cancer Treatment

Cancer survivors experience cancer-related cognitive impairment (CRCI) secondary to treatment. Chemotherapy and radiation therapy independently contribute to cognitive dysfunction; however, the underlying mechanisms leading to dysfunction remain unclear. We characterized brain gene expression changes in a mouse model of CRCI to identify the mechanistic underpinnings. Eleven-to-twelve-week-old SKH1 mice were treated with doxorubicin (DOX), hindlimb radiation (RT), concurrent hindlimb radiation and doxorubicin (DOX-RT), or no treatment (control). Sixteen days following treatment, gene expression was measured from murine brains using the NanoString nCounter® glial profiling panel. Gene expression was normalized and compared between groups. No two groups shared the same expression pattern, and only Gnb1 and Srpr were upregulated in multiple treatment groups. Brains from DOX-treated mice had upregulated Atf2, Atp5b, Gnb1, Rad23b, and Srpr and downregulated Sirt5 expression compared to control brains. Brains from RT-treated mice demonstrated increased Abcg2 and Fgf2 and decreased C1qa and C1qb expression compared to control brains. Brains from DOX-RT-treated mice had upregulated Adar, E2f3, Erlec1, Gnb1, Srpr, Vim, and Pdgfra expression and downregulated Rock2 and Inpp5f expression compared to control brains. The gene expression changes demonstrated here highlight roles for neuronal transmission and oxidative stress in the pathogenesis of doxorubicin-related CRCI and inflammation in RT-related CRCI.

Mitochondrial dysfunction at the crossroad of cardiovascular diseases and cancer

A large body of evidence indicates the existence of a complex pathophysiological relationship between cardiovascular diseases and cancer. Mitochondria are crucial organelles whose optimal activity is determined by quality control systems, which regulate critical cellular events, ranging from intermediary metabolism and calcium signaling to mitochondrial dynamics, cell death and mitophagy. Emerging data indicate that impaired mitochondrial quality control drives myocardial dysfunction occurring in several heart diseases, including cardiac hypertrophy, myocardial infarction, ischaemia/reperfusion damage and metabolic cardiomyopathies. On the other hand, diverse human cancers also dysregulate mitochondrial quality control to promote their initiation and progression, suggesting that modulating mitochondrial homeostasis may represent a promising therapeutic strategy both in cardiology and oncology. In this review, first we briefly introduce the physiological mechanisms underlying the mitochondrial quality control system, and then summarize the current understanding about the impact of dysregulated mitochondrial functions in cardiovascular diseases and cancer. We also discuss key mitochondrial mechanisms underlying the increased risk of cardiovascular complications secondary to the main current anticancer strategies, highlighting the potential of strategies aimed at alleviating mitochondrial impairment-related cardiac dysfunction and tumorigenesis. It is hoped that this summary can provide novel insights into precision medicine approaches to reduce cardiovascular and cancer morbidities and mortalities.

Potential role of the apelin-APJ pathway in sex-related differential cardiotoxicity induced by doxorubicin in mice

Preclinical and clinical findings suggest sexual dimorphism in cardiotoxicity induced by a chemotherapeutic drug, doxorubicin (DOX). However, molecular alterations leading to sex-related differential vulnerability of heart to DOX toxicity are not fully explored. In the present study, RNA sequencing in hearts of B6C3F₁ mice indicated more differentially expressed genes in males than females (224 vs. 19; ≥1.5-fold, False Discovery Rate [FDR] < 0.05) at 1 week after receiving 24 mg/kg total cumulative DOX dose that induced cardiac lesions only in males. Pathway analysis further revealed probable inactivation of cardiac apelin fibroblast signaling pathway (p = 0.00004) only in DOX-treated male mice that showed ≥1.25-fold downregulation in the transcript and protein levels of the apelin receptor, APJ. In hearts of DOX-treated females, the transcript levels of apelin (1.24-fold) and APJ (1.47-fold) were significantly (p < 0.05) increased compared to saline-treated controls. Sex-related differential DOX effect was also observed on molecular targets downstream of the apelin-APJ pathway in cardiac fibroblasts and cardiomyocytes. In cardiac fibroblasts, upregulation of Tgf-β2, Ctgf, Sphk1, Serpine1, and Timp1 (fibrosis; FDR < 0.05) in DOX-treated males and upregulation of only Tgf-β2 and Timp1 (p < 0.05) in females suggested a greater DOX toxicity in hearts of males than females. Additionally, Ryr2 and Serca2 (calcium handling; FDR < 0.05) were downregulated in conjunction with 1.35-fold upregulation of Casp12 (sarcoplasmic reticulum-mediated apoptosis; FDR < 0.05) in DOX-treated male mice. Drug effect on the transcript level of these genes was less severe in female hearts. Collectively, these data suggest a likely role of the apelin-APJ axis in sex-related differential DOX-induced cardiotoxicity in our mouse model.

Low-Dose Radiation Reduces Doxorubicin-Induced Myocardial Injury Through Mitochondrial Pathways

The use of doxorubicin (DOX) as an anthraquinone antineoplastic agent is limited due to its cardiotoxicity. Our previous study suggested that low-dose radiation (LDR) could mitigate the cardiotoxicity induced by DOX via suppressing oxidative stress and cell apoptosis. However, the molecular targets and protective mechanism of LDR are not understood. In the present study, we sought to investigate the mechanisms underlying LDR's cardioprotection. Balb/c mice were randomly divided into four groups: Control group (no treatment), DOX group, LDR group (75 mGy), and LDR-72 h-DOX group (LDR pretreatment followed by intraperitoneal injection of DOX). Electron microscopy, PCR, and Western blot analyses indicated that LDR pretreatment mitigated changes in mitochondrial morphology caused by DOX, upregulated activity of mitochondrial complexes, and restored ATP levels in cardiomyocytes that were decreased by DOX. Whole genome microarray and PCR analyses showed that mitochondrial-related genes were altered by LDR pretreatment. Thus, our study showed that LDR can protect cardiomyocytes against DOX through improving mitochondrial function and increasing ATP production. This research could inform DOX chemotherapy strategies and provide new insight into the molecule mechanisms underlying the cardioprotective effects of LDR.

The Role of Mitochondrial Quality Control in Anthracycline-Induced Cardiotoxicity: From Bench to Bedside

Cardiotoxicity is the major side effect of anthracyclines (doxorubicin, daunorubicin, epirubicin, and idarubicin), though being the most commonly used chemotherapy drugs and the mainstay of therapy in solid and hematological neoplasms. Advances in the field of cardio-oncology have expanded our understanding of the molecular mechanisms underlying anthracycline-induced cardiotoxicity (AIC). AIC has a complex pathogenesis that includes a variety of aspects such as oxidative stress, autophagy, and inflammation. Emerging evidence has strongly suggested that the loss of mitochondrial quality control (MQC) plays an important role in the progression of AIC. Mitochondria are vital organelles in the cardiomyocytes that serve as the key regulators of reactive oxygen species (ROS) production, energy metabolism, cell death, and calcium buffering. However, as mitochondria are susceptible to damage, the MQC system, including mitochondrial dynamics (fusion/fission), mitophagy, mitochondrial biogenesis, and mitochondrial protein quality control, appears to be crucial in maintaining mitochondrial homeostasis. In this review, we summarize current evidence on the role of MQC in the pathogenesis of AIC and highlight the therapeutic potential of restoring the cardiomyocyte MQC system in the prevention and intervention of AIC.

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

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

Sublethal doxorubicin promotes migration and invasion of breast cancer cells: role of Src Family non-receptor tyrosine kinases

BACKGROUND

Doxorubicin (Dox) is a widely used chemotherapy, but its effectiveness is limited by dose-dependent side effects. Although lower Dox doses reduce this risk, studies have reported higher recurrence of local disease with no improvement in survival rate in patients receiving low doses of Dox. To effectively mitigate this, a better understanding of the adverse effects of suboptimal Dox doses is needed.

METHODS

Effects of sublethal dose of Dox on phenotypic changes were assessed with light and confocal microscopy. Migratory and invasive behavior were assessed by wound healing and transwell migration assays. MTT and LDH release assays were used to analyze cell growth and cytotoxicity. Flow cytometry was employed to detect cell surface markers of cancer stem cell population. Expression and activity of matrix metalloproteinases were probed with qRT-PCR and zymogen assay. To identify pathways affected by sublethal dose of Dox, exploratory RNAseq was performed and results were verified by qRT-PCR in multiple cell lines (MCF7, ZR75-1 and U-2OS). Regulation of Src Family kinases (SFK) by key players in DNA damage response was assessed by siRNA knockdown along with western blot and qRT-PCR. Dasatinib and siRNA for Fyn and Yes was employed to inhibit SFKs and verify their role in increased migration and invasion in MCF7 cells treated with sublethal doses of Dox.

RESULTS

The results show that sublethal Dox treatment leads to increased migration and invasion in otherwise non-invasive MCF7 breast cancer cells. Mechanistically, these effects were independent of the epithelial mesenchymal transition, were not due to increased cancer stem cell population, and were not observed with other chemotherapies. Instead, sublethal Dox induces expression of multiple SFK-including Fyn, Yes, and Src-partly in a p53 and ATR-dependent manner. These effects were validated in multiple cell lines. Functionally, inhibiting SFKs with Dasatinib and specific downregulation of Fyn suppressed Dox-induced migration and invasion of MCF7 cells.

CONCLUSIONS

Overall, this study demonstrates that sublethal doses of Dox activate a pro-invasive, pro-migration program in cancer cells. Furthermore, by identifying SFKs as key mediators of these effects, our results define a potential therapeutic strategy to mitigate local invasion through co-treatment with Dasatinib.

The emerging therapeutic role of mesenchymal stem cells in anthracycline-induced cardiotoxicity

Mesenchymal stem cell (MSC)-based tissue regeneration therapy has been extensively investigated for cardiac regeneration over the past two decades. Numerous animal and clinical investigations demonstrated the efficacy of various types of MSCs towards myocardial protection and restoration against anthracycline-induced cardiotoxicity (AIC). It has been established that local or systemic administration of MSCs considerably improved the cardiac function, while ameliorating inflammatory responses and myocardial fibrosis. Several factors influence the outcomes of MSC treatment for AIC, including MSC types, dosages, and routes and duration of administration. In this review, we discuss the recent (from 2015 to 2020) experimental and clinical research on the preventive and regeneration efficacy of different types of MSCs (with or without supporting agents) against AIC, as well as the key factors responsible for MSC-mediated cardiac repair. In addition, challenges and future perspectives of MSC-based cardiac regeneration therapy are also outlined.

A switch in mechanism of action prevents doxorubicin-mediated cardiac damage

Cancer patients treated with doxorubicin are at risk of congestive heart failure due to doxorubicin-mediated cardiotoxicity via topoisomerase IIβ poisoning. Acute cardiac muscle damage occurs in response to the very first dose of doxorubicin, however, cardioprotection has been reported after co-treatment of doxorubicin with acyloxyalkyl ester prodrugs. The aim of this study was to examine the role played by various forms of acute cardiac damage mediated by doxorubicin and determine a mechanism for the cardioprotective effect of formaldehyde-releasing prodrug AN-9 (pivaloyloxymethyl butyrate). Doxorubicin-induced cardiac damage in BALB/c mice bearing mammary tumours was established with a single dose of doxorubicin (4 or 16 mg/kg) administered alone or in combination with AN-9 (100 mg/kg). AN-9 protected the heart from doxorubicin-induced myocardial apoptosis and also significantly reduced dsDNA breaks, independent from the level of doxorubicin biodistribution to the heart. Covalent incorporation of [¹⁴C]doxorubicin into DNA showed that the combination treatment yielded significantly higher levels of formaldehyde-mediated doxorubicin-DNA adducts compared to doxorubicin alone, yet this form of damage was associated with cardioprotection from apoptosis. The cardiac transcriptomic analysis indicates that the combination treatment initiates inflammatory response signalling pathways. Doxorubicin and AN-9 combination treatments were cardioprotective, yet preserved doxorubicin-mediated anti-tumour proliferation and apoptosis in mammary tumours. This was associated with a switch in doxorubicin action from cardiac topoisomerase IIβ poisoning to covalent-DNA adduct formation. Co-administration of doxorubicin and formaldehyde-releasing prodrugs, such as AN-9, may be a promising cardioprotective therapy while maintaining doxorubicin activity in primary mammary tumours.

The mRNA expression of Il6 and Pdcd1 are predictive and protective factors for doxorubicin‑induced cardiotoxicity

Anthracyclines, such as doxorubicin (DOX), have been widely used in the treatment of a number of different solid and hematological malignancies. However, these drugs can inflict cumulative dose-dependent and irreversible damage to the heart, and can occasionally lead to heart failure. The cardiotoxic susceptibility varies among patients treated with anthracycline, and delays in the recognition of cardiotoxicity can result in poor prognoses. Accordingly, if the risk of cardiotoxicity could be predicted prior to drug administration, it would aid in safer and more effective chemotherapy treatment. The present study was carried out to identify genes that can predict DOX-induced cardiotoxicity (DICT). In an in vivo study, mice cumulatively treated with DOX demonstrated increases in serum levels of cardiac enzymes (aspartate aminotransferase, lactate dehydrogenase, creatine kinase MB isoenzyme and troponin T), in addition to decreases in body and heart weights. These changes were indicative of DICT, but the severity of these effects varied among individual mice. In the current study, the correlation in these mice between the extent of DICT and circulating blood concentrations of relevant transcripts before DOX administration was analyzed. Among various candidate genes, the plasma mRNA levels of the genes encoding interleukin 6 (Il6) and programmed cell death 1 (Pdcd1) in blood exhibited significant and positive correlations with the severity of DICT. In an in vitro study using cardiomyocyte H9c2 cells, knockdown of Il6 or Pdcd1 by small interfering RNA was revealed to enhance DOX-induced apoptosis, as determined by luminescent assays. These results suggested that the levels of transcription of Il6 and Pdcd1 in cardiomyocytes serve a protective role against DICT, and that the accumulation of these gene transcripts in blood is a predictive marker for DICT. To the best of our knowledge, this is the first report to demonstrate a role for Il6 and Pdcd1 mRNA expression in DICT.

Liposomal doxorubicin attenuates cardiotoxicity via induction of interferon-related DNA damage resistance

AIMS

The clinical application of doxorubicin (DOX) is severely compromised by its cardiotoxic effects, which limit the therapeutic index and the cumulative dose. Liposomal encapsulation of DOX (Myocet®) provides a certain protective effect against cardiotoxicity by reducing myocardial drug accumulation. We aimed to evaluate transcriptomic responses to anthracyclines with different cardiotoxicity profiles in a translational large animal model for identifying potential alleviation strategies.

METHODS AND RESULTS

We treated domestic pigs with either DOX, epirubicin (EPI), or liposomal DOX and compared the cardiac, laboratory, and haemodynamic effects with saline-treated animals. Cardiotoxicity was encountered in all groups, reflected by an increase of plasma markers N-terminal pro-brain-natriuretic peptide and Troponin I and an impact on body weight. High morbidity of EPI-treated animals impeded further evaluation. Cardiac magnetic resonance imaging with gadolinium late enhancement and transthoracic echocardiography showed stronger reduction of the left and right ventricular systolic function and stronger myocardial fibrosis in DOX-treated animals than in those treated with the liposomal formulation. Gene expression profiles of the left and right ventricles were analysed by RNA-sequencing and validated by qPCR. Interferon-stimulated genes (ISGs), linked to DNA damage repair and cell survival, were downregulated by DOX, but upregulated by liposomal DOX in both the left and right ventricle. The expression of cardioprotective translocator protein (TSPO) was inhibited by DOX, but not its liposomal formulation. Cardiac fibrosis with activation of collagen was found in all treatment groups.

CONCLUSIONS

All anthracycline-derivatives resulted in transcriptional activation of collagen synthesis and processing. Liposomal packaging of DOX-induced ISGs in association with lower cardiotoxicity, which is of high clinical importance in anticancer treatment. Our study identified potential mechanisms for rational development of strategies to mitigate anthracycline-induced cardiomyopathy.

Curcumin suppresses doxorubicin-induced cardiomyocyte pyroptosis via a PI3K/Akt/mTOR-dependent manner

Background

Doxorubicin (DOX) is one of the most effective anti-neoplastic drugs although its clinical use is limited by the severe cardiotoxicity. Apoptosis and defective autophagy are believed to contribute to DOX-induced cardiotoxicity. Here we explored the effect of curcumin (Cur) on DOX-induced cardiac injury and the mechanism involved with a focus on oxidative stress, autophagy and pyroptosis.

Methods

Kunming mice were challenged with DOX (3 mg·kg^-1, i.p. every other day) with cohorts of mice receiving Cur at 50, 100, 200 and 400 mg·kg^-1 via gavage daily. Serum levels of cardiac enzymes, such as aspartate amino transferase (AST), lactate dehydrogenase (LDH), creatine kinase (CK), and heart homogenate oxidative stress markers, such as superoxide dismutase (SOD) and malondialdehyde (MDA) were determined. Echocardiographic and cardiac contraction were examined. Apoptosis, pyroptosis, autophagy and Akt/mTOR-signalling proteins were detected using western blot or electron microscopy. Cardiac contractile properties were assessed including peak shortening, maximal velocity of shortening/relengthening (± dL/dt), time-to-PS, and time-to-90% relengthening (TR90). Superoxide levels were evaluated using DHE staining. GFP-LC3 was conducted to measure autophagosomes.

Results

Our study showed that Cur protected against cardiotoxicity manifested by a significant decrease in serum myocardial enzymes and improvement of anti-oxidative capacity. Cur inhibited autophagy and offered overt benefit for cardiomyocyte survive against DOX-induced toxicity. Cur attenuated DOX-induced cardiomyocyte pyroptosis as evidenced by NLR family pyrin domain containing 3 (NLRP3), Caspase-1, and interleukin-18 levels. DOX impaired cardiac function (reduced fractional shortening, ejection fraction, increased plasma cTnI level and TR90, decreased PS and ± dL/dt), the effects of which were overtly reconciled by 100 mg·kg^-1 but not 50 mg·kg^-1 Cur. H9c2 cells exposure to DOX displayed increased intracellular reactive oxygen species (ROS) and autophagy, the effects of which were nullified by Cur. Autophagy activator rapamycin cancelled off Cur-induced protective effects.

Conclusions

Our finding suggested that Cur rescued against DOX-induced cardiac injury probably through regulation of autophagy and pyroptosis in a mTOR-dependent manner.

Quantitative Proteomic Profiling of Mitochondrial Toxicants in a Human Cardiomyocyte Cell Line

Mitochondria are essential cellular organelles that participate in important cellular processes, including bioenergetics, metabolism, and signaling. Recent functional and proteomic studies have revealed the remarkable complexity of mitochondrial protein organization. Mitochondrial protein machineries with diverse functions such as protein translocation, respiration, metabolite transport, protein quality control and the control of membrane architecture interact with each other in dynamic networks. The goal of this study was to identify protein expression changes in a human cardiomyocyte cell line treated with several mitochondrial toxicants which inhibit mitochondrial membrane potential (MMP) and mitochondrial respiration. AC16 human cardiomyocyte cells were treated with carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone (FCCP), dinoterb, picoxystrobin, pinacyanol, and triclocarban for 18 h around the IC₅₀ values generated from MMP assay. The samples were harvested and labeled with tandem mass tags with different mass isotopes. Peptide assignment was performed in Proteome Discoverer. Each dataset was analyzed in Ingenuity Pathway Analysis (IPA). In the proteomic profile, these compounds showed dysregulation of a group of mitochondrial proteins (e.g., NDUA, NDUB, BCS1, CYB5B, and SDHF2), as well as proteins involved in lipid metabolism (e.g., CPT, MECR, and LPGAT1), cytoskeleton protein changes (e.g., CROCC, LAMC3, FBLN1, and FMN2) and stress response (e.g., IKBKG, IKBB, SYVN1, SOD2, and CPIN1). Proteomic data from the current study provides key insights into chemical induced cellular pathway dysregulation, supporting the use of proteomic profiling as a sensitive method to further explore molecular functions and disease pathogenesis upon exposure to environmental chemicals.

Dexrazoxane ameliorates doxorubicin-induced cardiotoxicity by inhibiting both apoptosis and necroptosis in cardiomyocytes

Doxorubicin, as a first line chemotherapeutic agent, its usage is limited owing to cardiotoxicity. Necroptosis is a new form of programmed cell death, and recent investigations indicated that necroptosis is vitally involved in serious cardiac pathological conditions. Dexrazoxane is the only cardiac protective drug approved by FDA for anthracycline. We aimed to explore whether and how dexrazoxane regulates doxorubicin-induced cardiomyocyte necroptosis. First, doxorubicin could cause heart failure and reduce cardiomyocyte viability by promoting cell apoptosis and necroptosis in vivo and in vitro. Second, necroptosis plays an important role in doxorubicin induced cardiomyocyte injury, which could be inhibited by Nec-1. Third, dexrazoxane increased cell viability and protect heart function by decreasing both cardiomyocyte apoptosis and necroptosis after doxorubicin treatment. Forth, dexrazoxane attenuated doxorubicin-induced inflammation and necroptosis by the inhibition of p38MAPK/NF-κB pathways. These results indicated that dexrazoxane ameliorates cardiotoxicity and protects heart function by attenuating both apoptosis and necroptosis in doxorubicin induced cardiomyocyte injury.

Neonatal murine engineered cardiac tissue toxicology model: Impact of dexrazoxane on doxorubicin induced injury

Doxorubicin (DOX) induced cardiotoxicity is a life-threatening side effect of chemotherapy and decreased cardiac function can present years after treatment. Despite the investigation of a broad range of pharmacologic interventions, to date the only drug shown to reduce DOX-related cardiotoxicity in preclinical studies and limited clinical trials is the iron chelating agent, dexrazoxane (DRZ), although the mechanisms responsible for DRZ mediated protection from DOX related cardiotoxicity remain unclear. Engineered cardiac tissues (ECTs) can be used for tissue repair strategies and as in vitro surrogate models to test cardiac toxicities and preventative countermeasures. Neonatal murine ECTs display cardiotoxicity in response to the environmental toxin, cadmium, and reduced cadmium toxicity with Zinc co-treatment, in part via the induction of the anti-oxidant Metallothionein (MT). We adapted our in vitro ECT model to determine the feasibility of using the ECT approach to investigate DOX-related cardiac injury and DRZ prevention. We found: (1) DOX induced dose and time dependent cell death in ECTs; (2) Zinc did not show protection from DOX cardiotoxicity; (3) MT overexpression induced by Zinc, low dose Cd pretreatment, or MT-overexpression (MT-TG) did not reduce ECT DOX cardiotoxicity; (4) DRZ reduced ECT DOX induced cell death; and (5) The mechanism of DRZ ECT protection from DOX cardiotoxicity was topoisomerase 2B (TOP2B) inhibition rather than reduced reactive oxygen species. Our data support the feasibility of ECTs as an in vitro platform technology for the investigation of drug induced cardiotoxicities including the role of TOP2B in DOX toxicity and DRZ mediated DOX toxicity prevention.

Bone marrow mesenchymal stem cells alleviate the daunorubicin-induced subacute myocardial injury in rats through inhibiting infiltration of T lymphocytes and antigen-presenting cells

INTRODUCTION

Bone marrow mesenchymal stem cells (BMSCs) have been extensively investigated from a perspective on cardiac regeneration therapy. The current study aimed to investigate the protective effect conferred by BMSCs in subacute myocardial injury, and to identify an appropriate BMSC reinfusion time.

METHODS

BMSCs were isolated from human bone marrow blood. Daunorubicin (DNR)-induced subacute myocardial models were subsequently established. The rats with DNR-induced subacute myocardial injury were injected with dexrazoxane (DZR) and/or BMSCs at varying time points, after which cardiac function was evaluated by assessing left ventricular ejection fraction (LVEF) and fraction shortening (FS). The myocardial structural changes were analyzed, after which the levels of CD3 and human leukocyte antigen DR (HLA-DR) were examined to further validate the mechanism by which BMSCs could influence subacute myocardial injury.

RESULTS

BMSCs combined with DZR treatment enhanced the cardiac function of rats with DNR-induced myocardial injury, as reflected by increased LVEF and FS. DNR-induced myocardial injuries were mitigated via the application of BMSCs combined with treatment of DZR, accompanied by diminished infiltration or vacuolization. Moreover, BMSCs were observed to alleviate infiltration of T lymphocyte and antigen-presenting cells, as evidenced by reduced expression of CD3 and HLA-DR.

CONCLUSION

Taken together, this study demonstrates that BMSCs could protect against DNR-induced myocardial injury, especially in the first three days of DNR administration. BMSCs combined with DZR exert a better therapeutic effect, but there are individual differences.

Gene expression profiling of cultured mouse testis fragments treated with ethinylestradiol

The assessment of xenobiotic-induced testicular toxicity is important in drug development. Nonetheless, in vitro models to test drugs and chemicals that may cause testicular toxicity are lacking, requiring the continued use of animal models for those studies. We previously evaluated an in vitro mouse testis organ culture system using ethinylestradiol (EE), a well-studied testicular toxicant, and demonstrated a dose-dependent relationship between adverse effects to germ cell differentiation and increasing EE concentrations. However, we terminated that study after 20 days of culture due to oxygen deficiency during germ cell differentiation. Therefore, in the current study, we aimed to identify gene(s) with potential for supporting the histopathological evaluations of testicular toxicity using in vitro testis organ culture system. We cultured testis fragments obtained from mice at postnatal day (PND) 5 in α-Minimal Essential Medium containing 40 mg/mL AlbuMAX^™ I and treated them with 0.01 or 1 nM EE on day 1 of culture. On day 20, we collected testis fragments for RNA sequencing analysis and quantitative polymerase chain reaction (qPCR). We found that phospholipase C, zeta 1 and testis-specific serine kinase 4 genes, that are involved in spermatogenesis and predominantly expressed in the testis, were significantly reduced in testis fragments treated with the highest concentration of EE. Also, cytochrome P450, family 26, subfamily b, polypeptide 1 (Cyp26b1) and interleukin 16 (Il16) were up-regulated in the highest EE-treated groups. Further studies are needed to confirm the variations of these gene expression using other testicular toxicants.

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

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

Transcript profiling in the testes and prostates of postnatal day 30 Sprague-Dawley rats exposed prenatally and lactationally to 2-hydroxy-4-methoxybenzophenone

2-hydroxy-4-methoxybenzophenone (HMB) is an ultraviolet light-absorbing compound that is used in sunscreens, cosmetics and plastics. HMB has been reported to have weak estrogenic activity by in vivo and in vitro studies, making it a chemical with potential reproductive concern. To explore if prenatal and lactational HMB exposure alters gene expression profiles of the developing reproductive organs, we performed microarray analysis using the prostate and testis of postnatal day (PND) 30 male Sprague-Dawley rats offspring exposed to 0, 3000, or 30,000 ppm of HMB from gestational day 6 through PND 21. Gene expression profiles of the prostate and testis were differentially affected by HMB dose with significant alterations observed at the 30,000 ppm HMB group. Tissue-specific gene expression was also identified. These genes, whose expression was altered by HMB exposure, may be considered as candidate biomarker(s) for testicular or prostatic toxicity; however, further studies are necessary to explore this potential.

In Vitro Modulation of Redox and Metabolism Interplay at the Brain Vascular Endothelium: Genomic and Proteomic Profiles of Sulforaphane Activity

Sulforaphane (SFN) has been shown to protect the brain vascular system and effectively reduce ischemic injuries and cognitive deficits. Given the robust cerebrovascular protection afforded by SFN, the objective of this study was to profile these effects in vitro using primary mouse brain microvascular endothelial cells and focusing on cellular redox, metabolism and detoxification functions. We used a mouse MitoChip array developed and validated at the FDA National Center for Toxicological Research (NCTR) to profile a host of genes encoded by nuclear and mt-DNA following SFN treatment (0-5 µM). Corresponding protein expression levels were assessed (ad hoc) by qRT-PCR, immunoblots and immunocytochemistry (ICC). Gene ontology clustering revealed that SFN treatment (24 h) significantly up-regulated ~50 key genes (>1.5 fold, adjusted p < 0.0001) and repressed 20 genes (<0.7 fold, adjusted p < 0.0001) belonging to oxidative stress, phase 1 & 2 drug metabolism enzymes (glutathione system), iron transporters, glycolysis, oxidative phosphorylation (OXPHOS), amino acid metabolism, lipid metabolism and mitochondrial biogenesis. Our results show that SFN stimulated the production of ATP by promoting the expression and activity of glucose transporter-1, and glycolysis. In addition, SFN upregulated anti-oxidative stress responses, redox signaling and phase 2 drug metabolism/detoxification functions, thus elucidating further the previously observed neurovascular protective effects of this compound.

Prevention of cardiotoxicity among survivors of childhood cancer

LINKED ARTICLES

This article is part of a joint Themed section with the British Journal of Pharmacology on Cardiotoxicity. The rest of the Themed section will appear in a future issue of BJP and will be available at http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1476-5381 The number of survivors of childhood cancers has increased exponentially over the past few decades. However, these survivors are also at substantially increased long-term risk of morbidity and mortality, especially from treatment-related cardiotoxicity. Preventing these risks is now a priority when treating children and adolescents with cancer. Dexrazoxane reduces the risk of anthracycline-induced cardiotoxicity among adults and children with cancer without reducing its antineoplastic effects or event-free survival. Thus, it should be strongly considered as a part of therapy for children and adolescents treated with anthracyclines.

Protective Effects of Dexrazoxane against Doxorubicin-Induced Cardiotoxicity: A Metabolomic Study

Cardioprotection of dexrazoxane (DZR) against doxorubicin (DOX)-induced cardiotoxicity is contentious and the indicator is controversial. A pairwise comparative metabolomics approach was used to delineate the potential metabolic processes in the present study. Ninety-six BALB/c mice were randomly divided into two supergroups: tumor and control groups. Each supergroup was divided into control, DOX, DZR, and DOX plus DZR treatment groups. DOX treatment resulted in a steady increase in 5-hydroxylysine, 2-hydroxybutyrate, 2-oxoglutarate, 3-hydroxybutyrate, and decrease in glucose, glutamate, cysteine, acetone, methionine, asparate, isoleucine, and glycylproline.DZR treatment led to increase in lactate, 3-hydroxybutyrate, glutamate, alanine, and decrease in glucose, trimethylamine N-oxide and carnosine levels. These metabolites represent potential biomarkers for early prediction of cardiotoxicity of DOX and the cardioprotective evaluation of DZR.

Early metabolomics changes in heart and plasma during chronic doxorubicin treatment in B6C3F1 mice

The present study aimed to identify molecular markers of early stages of cardiotoxicity induced by a potent chemotherapeutic agent, doxorubicin (DOX). Male B6C3F1 mice were dosed with 3 mg kg(-1) DOX or saline via tail vein weekly for 2, 3, 4, 6 or 8 weeks (cumulative DOX doses of 6, 9, 12, 18 or 24 mg kg(-1) , respectively) and euthanized a week after the last dose. Mass spectrometry-based and nuclear magnetic resonance spectrometry-based metabolic profiling were employed to identify initial biomarkers of cardiotoxicity before myocardial injury and cardiac pathology, which were not noted until after the 18 and 24 mg kg(-1) cumulative doses, respectively. After a cumulative dose of 6 mg kg(-1) , 18 amino acids and four biogenic amines (acetylornithine, kynurenine, putrescine and serotonin) were significantly increased in cardiac tissue; 16 amino acids and two biogenic amines (acetylornithine and hydroxyproline) were significantly altered in plasma. In addition, 16 acylcarnitines were significantly increased in plasma and five were significantly decreased in cardiac tissue compared to saline-treated controls. Plasma lactate and succinate, involved in the Krebs cycle, were significantly altered after a cumulative dose of 6 mg kg(-1) . A few metabolites remained altered at higher cumulative DOX doses, which could partly indicate a transition from injury processes at 2 weeks to repair processes with additional injury happening concurrently before myocardial injury at 8 weeks. These altered metabolic profiles in mouse heart and plasma during the initial stages of injury progression due to DOX treatment may suggest these metabolites as candidate early biomarkers of cardiotoxicity. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.