Clinically Translatable Prevention of Anthracycline Cardiotoxicity by Dexrazoxane Is Mediated by Topoisomerase II Beta and Not Metal Chelation

Background: Anthracycline-induced heart failure has been traditionally attributed to direct iron-catalyzed oxidative damage. Dexrazoxane (DEX)—the only drug approved for its prevention—has been believed to protect the heart via its iron-chelating metabolite ADR-925. However, direct evidence is lacking, and recently proposed TOP2B (topoisomerase II beta) hypothesis challenged the original concept. Methods: Pharmacokinetically guided study of the cardioprotective effects of clinically used DEX and its chelating metabolite ADR-925 (administered exogenously) was performed together with mechanistic experiments. The cardiotoxicity was induced by daunorubicin in neonatal ventricular cardiomyocytes in vitro and in a chronic rabbit model in vivo (n=50). Results: Intracellular concentrations of ADR-925 in neonatal ventricular cardiomyocytes and rabbit hearts after treatment with exogenous ADR-925 were similar or exceeded those observed after treatment with the parent DEX. However, ADR-925 did not protect neonatal ventricular cardiomyocytes against anthracycline toxicity, whereas DEX exhibited significant protective effects (10–100 µmol/L; P <0.001). Unlike DEX, ADR-925 also had no significant impact on daunorubicin-induced mortality, blood congestion, and biochemical and functional markers of cardiac dysfunction in vivo (eg, end point left ventricular fractional shortening was 32.3±14.7%, 33.5±4.8%, 42.7±1.0%, and 41.5±1.1% for the daunorubicin, ADR-925 [120 mg/kg]+daunorubicin, DEX [60 mg/kg]+daunorubicin, and control groups, respectively; P <0.05). DEX, but not ADR-925, inhibited and depleted TOP2B and prevented daunorubicin-induced genotoxic damage. TOP2B dependency of the cardioprotective effects was probed and supported by experiments with diastereomers of a new DEX derivative. Conclusions: This study strongly supports a new mechanistic paradigm that attributes clinically effective cardioprotection against anthracycline cardiotoxicity to interactions with TOP2B but not metal chelation and protection against direct oxidative damage.

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Synthesis and analysis of novel analogues of dexrazoxane and its open-ring hydrolysis product for protection against anthracycline cardiotoxicity in vitro and in vivo

Toxicology Research ◽

10.1039/c5tx00048c ◽

2015 ◽

Vol 4 (4) ◽

pp. 1098-1114 ◽

Cited By ~ 14

Author(s):

Anna Jirkovská-Vávrová ◽

Jaroslav Roh ◽

Olga Lenčová-Popelová ◽

Eduard Jirkovský ◽

Kateřina Hrušková ◽

...

Keyword(s):

Topoisomerase Ii ◽

Hydrolysis Product ◽

Iron Chelation ◽

Anthracycline Cardiotoxicity ◽

Promising Target ◽

Open Ring ◽

Topoisomerase Ii Beta

Topoisomerase II beta, rather than (or along with) iron chelation, may be a promising target for cardioprotection.

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Prodrug of ICRF-193 provides promising protective effects against chronic anthracycline cardiotoxicity on a rabbit model in vivo

Clinical Science ◽

10.1042/cs20210311 ◽

2021 ◽

Author(s):

Petra Kollárová-Brázdová ◽

Olga Lencova-Popelova ◽

Galina Karabanovich ◽

Júlia Kocúrová-Lengvarská ◽

Jan Kubes ◽

...

Keyword(s):

Rabbit Model ◽

Left Ventricular ◽

Water Soluble ◽

Drug Candidate ◽

Protective Effects ◽

Cardiac Damage ◽

Anthracycline Cardiotoxicity ◽

Lv Dysfunction ◽

Full Protection

The anthracycline (ANT) anticancer drugs such as doxorubicin or daunorubicin (DAU) can cause serious myocardial injury and chronic cardiac dysfunction in cancer survivors. A bisdioxopiperazine agent dexrazoxane has been developed as a cardioprotective drug to prevent these adverse events, but it is uncertain whether it is the best representative of the class. This study used a rabbit model of chronic ANT cardiotoxicity to examine another bisdioxopiperazine compound called GK-667, a water-soluble prodrug of ICRF-193, as a potential cardioprotectant. The cardiotoxicity was induced by DAU (3 mg/kg, i.v. weekly, 10 weeks), and GK-667 (1 or 5 mg/kg, i.v.) was administered before each DAU dose. The treatment with GK-667 was well tolerated and provided full protection against DAU-induced mortality and left ventricular (LV) dysfunction (determined by echocardiography and LV catheterization). Markers of cardiac damage/dysfunction revealed minor cardiac damage in the group co-treated with GK-667 in the lower dose, whereas almost full protection was achieved with the higher dose. This was associated with similar prevention of DAU-induced dysregulation of redox and calcium homeostasis proteins. GK-667 dose-dependently prevented p53-mediated DNA damage response in the LV myocardium not only in the chronic experiment but also after single DAU administration. These effects appear essential for cardioprotection, presumably because of the topoisomerase IIβ inhibition provided by its active metabolite ICRF-193. In addition, GK-667 administration did not alter the plasma pharmacokinetics of DAU and its main metabolite daunorubicinol in rabbits in vivo. Hence, GK-667 merits further investigation as a promising drug candidate for cardioprotection against chronic ANT cardiotoxicity.

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79 Effective cardioprotection against anthracycline cardiotoxicity in isolated cardiomyocytes and rabbits is based on dexrazoxane interaction with topoisomerase II beta instead of iron chelation by its metabolite ADR-925

10.1136/heartjnl-2019-bcs.77 ◽

2019 ◽

Author(s):

Eduard Jirkovsky ◽

Anna Jirkovska ◽

Hana Bavlovic-Piskackova ◽

Veronika Skalicka ◽

Zuzana Pokorna ◽

...

Keyword(s):

Topoisomerase Ii ◽

Iron Chelation ◽

Isolated Cardiomyocytes ◽

Anthracycline Cardiotoxicity ◽

Topoisomerase Ii Beta

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Development of water-soluble prodrugs of the bisdioxopiperazine topoisomerase IIβ inhibitor ICRF-193 as potential cardioprotective agents against anthracycline cardiotoxicity

Scientific Reports ◽

10.1038/s41598-021-83688-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Hana Bavlovič Piskáčková ◽

Hana Jansová ◽

Jan Kubeš ◽

Galina Karabanovich ◽

Nela Váňová ◽

...

Keyword(s):

Plasma Concentrations ◽

Aqueous Solubility ◽

Water Soluble ◽

Drug Candidate ◽

Anthracycline Cardiotoxicity ◽

Cardioprotective Effects ◽

Low Cytotoxicity ◽

Anthracycline Toxicity

AbstractThe bisdioxopiperazine topoisomerase IIβ inhibitor ICRF-193 has been previously identified as a more potent analog of dexrazoxane (ICRF-187), a drug used in clinical practice against anthracycline cardiotoxicity. However, the poor aqueous solubility of ICRF-193 has precluded its further in vivo development as a cardioprotective agent. To overcome this issue, water-soluble prodrugs of ICRF-193 were prepared, their abilities to release ICRF-193 were investigated using a novel UHPLC-MS/MS assay, and their cytoprotective effects against anthracycline cardiotoxicity were tested in vitro in neonatal ventricular cardiomyocytes (NVCMs). Based on the obtained results, the bis(2-aminoacetoxymethyl)-type prodrug GK-667 was selected for advanced investigations due to its straightforward synthesis, sufficient solubility, low cytotoxicity and favorable ICRF-193 release. Upon administration of GK-667 to NVCMs, the released ICRF-193 penetrated well into the cells, reached sufficient intracellular concentrations and provided effective cytoprotection against anthracycline toxicity. The pharmacokinetics of the prodrug, ICRF-193 and its rings-opened metabolite was estimated in vivo after administration of GK-667 to rabbits. The plasma concentrations of ICRF-193 reached were found to be adequate to achieve cardioprotective effects in vivo. Hence, GK-667 was demonstrated to be a pharmaceutically acceptable prodrug of ICRF-193 and a promising drug candidate for further evaluation as a potential cardioprotectant against chronic anthracycline toxicity.

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Jasminum sambac: A Potential Candidate for Drug Development to Cure Cardiovascular Ailments

Molecules ◽

10.3390/molecules26185664 ◽

2021 ◽

Vol 26 (18) ◽

pp. 5664

Author(s):

Imran Ahmad Khan ◽

Musaddique Hussain ◽

Shaukat Hussain Munawar ◽

Muhammad Omer Iqbal ◽

Shafia Arshad ◽

...

Keyword(s):

Ex Vivo ◽

Hypotensive Effect ◽

Left Ventricular ◽

Potential Candidate ◽

Medicinal Uses ◽

Mechanistic Investigation ◽

Crude Leaf Extract ◽

Cardioprotective Effects ◽

Jasminum Sambac

Jasminum sambac (L.) is a South Asian folkloric medicinal plant that has traditionally been used to treat cardiovascular problems. The current investigation was meticulously organized to explore the pharmacological foundation for the medicinal uses of J. sambac pertaining to cardiovascular ailments and to investigate the core mechanisms. Mechanistic investigation revealed that crude leaf extract of J. sambac produced ex-vivo vasorelaxant effects in endotheliumintact aorta ring preparation and hypotensive effect was recorded via pressure and force transducers coupled to the Power Lab Data Acquisition System. Moreover; J. sambac showed cardioprotective effects against adrenaline -induced left ventricular hypertrophy in rabbits observed hemodynamic. CK-MB, LDH, troponin, CRP, ALT, AST, ALP levels were shown to be lower in the myocardial infarction model, as were necrosis, oedema, and inflammatory cell recruitment in comparison to control. J. sambac has shown good antioxidant potential as well as prolonged the noradrenaline induced platelet adhesion. The vasorelaxant and cardioprotective effects in both in vivo and ex vivo experiments, which are enabled by activation of muscarinic receptor and/or releasing the nitric oxide and by reducing the adrenaline, induced oxidative stress, justifying its usage in cardiovascular disorders.

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The chemotherapeutic CX-5461 primarily targets TOP2B and exhibits selective activity in high-risk neuroblastoma

10.1101/2021.02.25.432934 ◽

2021 ◽

Author(s):

Min Pan ◽

William C. Wright ◽

Rich Chapple ◽

Asif Zubair ◽

Manbir Sandhu ◽

...

Keyword(s):

High Risk ◽

Topoisomerase I ◽

Topoisomerase Ii ◽

Primary Target ◽

Minimal Impact ◽

Pol I ◽

Fatal Adverse Events ◽

Topoisomerase Ii Beta

ABSTRACTSurvival in high-risk pediatric neuroblastoma has remained around 50% for the last 20 years, with immunotherapies and targeted therapies having had minimal impact. Here, we identify the small molecule CX-5461 as selectively cytotoxic to high-risk neuroblastoma and synergistic with low picomolar concentrations of topoisomerase I inhibitors improving survival in vivo in orthotopic patient-derived xenograft neuroblastoma mouse models. CX-5461 recently progressed through phase I clinical trial as a first-in-human inhibitor of RNA-POL I. However, we also use a comprehensive panel of in vitro and in vivo assays to demonstrate that CX-5461 has been mischaracterized and that its primary target at pharmacologically relevant concentrations, is in fact topoisomerase II beta (TOP2B), not RNA-POL I. These findings are important because existing clinically approved chemotherapeutics have well-documented off-target interactions with TOP2B, which have previously been shown to cause both therapy-induced leukemia and cardiotoxicity—often-fatal adverse events, which can emerge several years after treatment. Thus, while we show that combination therapies involving CX-5461 have promising anti-tumor activity in vivo in neuroblastoma, our identification of TOP2B as the primary target of CX-5461 indicates unexpected safety concerns that should be examined in ongoing phase II clinical trials in adult patients before pursuing clinical studies in children.

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The chemotherapeutic CX-5461 primarily targets TOP2B and exhibits selective activity in high-risk neuroblastoma

Nature Communications ◽

10.1038/s41467-021-26640-x ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Min Pan ◽

William C. Wright ◽

Richard H. Chapple ◽

Asif Zubair ◽

Manbir Sandhu ◽

...

Keyword(s):

High Risk ◽

Topoisomerase I ◽

Topoisomerase Ii ◽

Primary Target ◽

Minimal Impact ◽

Pol I ◽

Fatal Adverse Events ◽

Topoisomerase Ii Beta

AbstractSurvival in high-risk pediatric neuroblastoma has remained around 50% for the last 20 years, with immunotherapies and targeted therapies having had minimal impact. Here, we identify the small molecule CX-5461 as selectively cytotoxic to high-risk neuroblastoma and synergistic with low picomolar concentrations of topoisomerase I inhibitors in improving survival in vivo in orthotopic patient-derived xenograft neuroblastoma mouse models. CX-5461 recently progressed through phase I clinical trial as a first-in-human inhibitor of RNA-POL I. However, we also use a comprehensive panel of in vitro and in vivo assays to demonstrate that CX-5461 has been mischaracterized and that its primary target at pharmacologically relevant concentrations, is in fact topoisomerase II beta (TOP2B), not RNA-POL I. This is important because existing clinically approved chemotherapeutics have well-documented off-target interactions with TOP2B, which have previously been shown to cause both therapy-induced leukemia and cardiotoxicity—often-fatal adverse events, which can emerge several years after treatment. Thus, while we show that combination therapies involving CX-5461 have promising anti-tumor activity in vivo in neuroblastoma, our identification of TOP2B as the primary target of CX-5461 indicates unexpected safety concerns that should be examined in ongoing phase II clinical trials in adult patients before pursuing clinical studies in children.

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The in vivo distribution and dynamics of DNA topoisomerase II in Drosophila embryonic nuclei and chromosomes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100146217 ◽

1993 ◽

Vol 51 ◽

pp. 74-75

Author(s):

Jason R. Swedlow ◽

Neil Osheroff ◽

Tim Karr ◽

John W. Sedat ◽

David A. Agard

Keyword(s):

Topoisomerase Ii ◽

Biochemical Characterization ◽

Developmental Cycle ◽

Dna Topoisomerase Ii ◽

Chromosomal Distribution ◽

Dna Topoisomerase ◽

Ideal System ◽

Dnase Treatment

DNA topoisomerase II is an ATP-dependent double-stranded DNA strand-passing enzyme that is necessary for full condensation of chromosomes and for complete segregation of sister chromatids at mitosis in vivo and in vitro. Biochemical characterization of chromosomes or nuclei after extraction with high-salt or detergents and DNAse treatment showed that topoisomerase II was a major component of this remnant, termed the chromosome scaffold. The scaffold has been hypothesized to be the structural backbone of the chromosome, so the localization of topoisomerase II to die scaffold suggested that the enzyme might play a structural role in the chromosome. However, topoisomerase II has not been studied in nuclei or chromosomes in vivo. We have monitored the chromosomal distribution of topoisomerase II in vivo during mitosis in the Drosophila embryo. This embryo forms a multi-nucleated syncytial blastoderm early in its developmental cycle. During this time, the embryonic nuclei synchronously progress through 13 mitotic cycles, so this is an ideal system to follow nuclear and chromosomal dynamics.

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Effects of Rest and Exercise on Cardiac Blood Volume Determinations

Nuklearmedizin ◽

10.1055/s-0038-1629844 ◽

1997 ◽

Vol 36 (08) ◽

pp. 259-264

Author(s):

N. Topuzović

Keyword(s):

Radionuclide Ventriculography ◽

Left Ventricular ◽

Peak Exercise ◽

Volume Determination ◽

Group I ◽

Lv Volumes ◽

Group Ii ◽

Lv Volume

Summary Aim: The purpose of this study was to investigate the changes in blood activity during rest, exercise and recovery, and to assess its influence on left ventricular (LV) volume determination using the count-based method requiring blood sampling. Methods: Forty-four patients underwent rest-stress radionuclide ventriculography; Tc-99m-human serum albumin was used in 13 patients (Group I), red blood cells was labeled using Tc-99m in 17 patients (Group II) in vivo, and in 14 patients (Group III) by modified in vivo/in vitro method. LV volumes were determined by a count-based method using corrected count rate in blood samples obtained during rest, peak exercise and after recovery. Results: In group I at stress, the blood activity decreased by 12.6 ± 5.4%, p <0.05, as compared to the rest level, and increased by 25.1 ± 6.4%, p <0.001, and 12.8 ± 4.5%, p <0.05, above the resting level in group II and III, respectively. This had profound effects on LV volume determinations if only one rest blood aliquot was used: during exercise, the LV volumes significantly decreased by 22.1 ± 9.6%, p <0.05, in group I, whereas in groups II and III it was significantly overestimated by 32.1 ± 10.3%, p <0.001, and 10.7 ± 6.4%, p <0.05, respectively. The changes in blood activity between stress and recovery were not significantly different for any of the groups. Conclusion: The use of only a single blood sample as volume aliquot at rest in rest-stress studies leads to erroneous estimation of cardiac volumes due to significant changes in blood radioactivity during exercise and recovery.

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Glutamine Is Cardioprotective in Patients with Ischemic Heart Disease following Cardiopulmonary Bypass

The Heart Surgery Forum ◽

10.1532/hsf98.20111074 ◽

2011 ◽

Vol 14 (6) ◽

pp. 384 ◽

Cited By ~ 17

Author(s):

Vladimir V. Lomivorotov ◽

Sergey M. Efremov ◽

Vladimir A. Shmirev ◽

Dmitry N. Ponomarev ◽

Vladimir N. Lomivorotov ◽

...

Keyword(s):

Heart Disease ◽

Placebo Group ◽

Cardiopulmonary Bypass ◽

Ischemic Heart Disease ◽

Troponin I ◽

Left Ventricular ◽

Ischemic Heart ◽

Left Ventricular Ejection ◽

Study Group ◽

Cardioprotective Effects

Background: The aim of the present study was to investigate the cardioprotective effects of the perioperative use of N(2)-L-alanyl-L-glutamine (GLN) in patients with ischemic heart disease (IHD) who undergo their operations under cardiopulmonary bypass (CPB).Methods: This double-blind, placebo-controlled, randomized study included 50 patients who underwent cardiac surgery with CPB. Exclusion criteria were a left ventricular ejection fraction <50%, diabetes mellitus, <3 months since the onset of myocardial infarction, and emergency surgery. Patients in the study group (n = 25) received 0.4 g/kg GLN (Dipeptiven, 20% solution) per day. Patients in the control group (n = 25) were administered a placebo (0.9% NaCl). The primary end point was the dynamics of troponin I at the following stages: (1) prior to anesthesia, (2) 30 minutes after CPB, (3) 6 hours after CPB, (4) 24 hours after surgery, and (5) 48 hours after surgery. Secondary end points included measurements of hemodynamics with a Swan-Ganz catheter.Results: On the first postoperative day after the surgery, the median troponin I level was significantly lower in the study group than in the placebo group: 1.280 ng/mL (interquartile range [IQR], 0.840-2.230 ng/mL) versus 2.410 ng/mL (IQR, 1.060-6.600 ng/mL) (P = .035). At 4 hours after cardiopulmonary bypass (CPB), the median cardiac index was higher in the patients in the study group: 2.58 L/min per m2 (IQR, 2.34-2.91 L/min per m2) versus 2.03 L/min per m2 (IQR, 1.76-2.32 L/min per m2) (P = .002). The median stroke index also was higher in the patients who received GLN: 32.8 mL/m2 (IQR, 27.8-36.0 mL/m2) versus 26.1 mL/m2 (IQR, 22.6-31.8 mL/m2) (P = .023). The median systemic vascular resistance index was significantly lower in the study group than in the placebo group: 1942 dyn�s/cm5 per m2 (IQR, 1828-2209 dyn�s/cm5 per m2) versus 2456 dyn�s/cm5 per m2 (IQR, 2400-3265 dyn�s/cm5 per m2) (P = .001).Conclusion: Perioperative administration of GLN during the first 24 hours has cardioprotective effects in IHD patients following CPB. This technique enhances the troponin concentration at 24 hours after surgery and is associated with improved myocardial function.

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