Topobexin
Based on 1 Customer Validation
Topobexin is a TOP2B-selective inhibitor with IC50 values of 0.19 μM and 4.8 μM for TOP2B and TOP2A (DNA decatenation assay). Topobexin binds to non-homologous residues in the obex pocket and targets the ATPase domain of TOP2B. Topobexin prevents anthracycline-induced DNA double-strand break formation, apoptotic signaling mediated by caspase 3/7, 8 and 9, cardiomyocyte morphological changes, mitochondrial depolarization/loss, left ventricular systolic dysfunction, extracellular matrix remodeling, fibrotic alterations, and increases in plasma cardiac troponin T and BNP. Topobexin does not impair the antiproliferative effects of anthracyclines in cancer cells, exhibits no intrinsic cytotoxicity in cardiomyocytes, and is well tolerated in rabbits. Topobexin can be used in studies related to anthracycline-induced cardiotoxicity.
For research use only. We do not sell to patients.
- Purity: 99.04%
- CAS No.: 3076446-44-8
- Formula: C29H35N3O4
- Molecular Weight:489.61
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Storage:Powder -20°C, 3 years , 4°C, 2 years ; In solvent -80°C, 6 months , -20°C, 1 month
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Biological Activity
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Chemical Information
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Solvent & Solubility
- Purity & Documentation
- References
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All Topoisomerase Isoforms
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Biological Activity
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topoisomerase II beta 0.19 μM (IC50) |
topoisomerase II alpha 4.8 μM (IC50) |
Topobexin (0.03-30 μM; 40 min) potently and selectively inhibits recombinant human TOP2B over TOP2A in a DNA decatenation assay, with an IC50 of 0.19 μM for TOP2B[1].
Topobexin (0.02-20 μM) selectively inhibits recombinant human TOP2B ATPase activity over TOP2A, with an IC50 of 0.35 μM for TOP2B and a selectivity ratio of 12[1].
Topobexin binds to the obex pocket of human TOP2A and TOP2B ATPase domains, with steric strain induced by the TOP2A-unique Y72 residue driving its preferential inhibition of TOP2B[1].
Topobexin (0.25-1 μM; 15 min) selectively inhibits and immobilizes YFP-TOP2B on DNA in HEK293F cells, without affecting YFP-TOP2A mobility[1].
Topobexin (10 μM; 3 hours) treatment of wild-type human induced pluripotent stem cell-derived cardiomyocytes partially phenocopies TOP2B gene inactivation, as evidenced by a significant positive correlation in transcriptomic changes between Topobexin-treated cells and TOP2B-knockout cardiomyocytes[3].
MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.
| Species | Dose | Route | Cmax | Tmax |
|---|---|---|---|---|
| Rabbit[1] | 10 mg/kg | i.v. | 13.5 μM | 10 min |
Topobexin (10 mg/kg; i.v.; once weekly; 10 weeks) completely prevents chronic Daunorubicin-induced cardiotoxicity in rabbits, preserving LV systolic function, blocking cardiomyocyte damage and pathological myocardial remodeling, and improving survival[1].
MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.
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Animal Model:New Zealand White (male, 12-16 weeks old) (Anthracycline-induced cardiotoxicity)[1]
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Dosage:10 mg/kg
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Administration:i.v.; single 20 min infusion
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Result:Completely prevented the Daunorubicin-induced increase in left ventricular γH2AX, with levels comparable to saline-treated controls.
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Animal Model:New Zealand White (male, 12-16 weeks old) (Anthracycline-induced cardiotoxicity)[1]
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Dosage:10 mg/kg
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Administration:i.v.; once weekly; 10 weeks; 20 min infusion prior to each Daunorubicin dose
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Result:Ensured 100% survival to the scheduled end of the experiment, compared to one premature death in the Daunorubicin-only group.
Prevented Daunorubicin-induced decreases in left ventricular systolic function, with LV fractional shortening and LV dP/dt_max matching saline-treated controls.
Blocked Daunorubicin-induced elevations in plasma cardiac troponin T, LV BNP mRNA, and LV mRNA levels of fibronectin 1 and collagen I alpha1, with all markers comparable to saline controls.
Maintained body weight gain matching the Daunorubicin-only group, with no additional toxicity observed compared to saline controls.
Chemical Information
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CAS No. 3076446-44-8
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Appearance Solid
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Molecular Weight 489.61
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Formula C29H35N3O4
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Color White to off-white
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SMILES
CCCC1=CC(OC2=C(C(OCCN3CCN(CC3)C)=CC=C12)C(N4CCCC5=C4C=CC=C5)=O)=O
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Shipping
Room temperature in continental US; may vary elsewhere.
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Storage
Powder -20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month
Solvent & Solubility
DMSO : 25 mg/mL (51.06 mM; Need ultrasonic; Hygroscopic DMSO has a significant impact on the solubility of product, please use newly opened DMSO)
Please refer to the solubility information to select the appropriate solvent. Once prepared, please aliquot and store the solution to prevent product inactivation from repeated freeze-thaw cycles.
Storage method and period of stock solution: -80°C, 6 months; -20°C, 1 month. When stored at -80°C, please use it within 6 months. When stored at -20°C, please use it within 1 month.
Please refer to the solubility information to select the appropriate solvent. Once prepared, please aliquot and store the solution to prevent product inactivation from repeated freeze-thaw cycles.
Storage method and period of stock solution: -80°C, 6 months; -20°C, 1 month. When stored at -80°C, please use it within 6 months. When stored at -20°C, please use it within 1 month.
Concentration (start) × Volume (start) = Concentration (final) × Volume (final)
Select the appropriate dissolution method based on your experimental animal and administration route.
- For the following dissolution methods, please ensure to first prepare a clear stock solution using an In Vitro approach and then sequentially add co-solvents:
- To ensure reliable experimental results, the clarified stock solution can be appropriately stored based on storage conditions. As for the working solution for In Vivo experiments, it is recommended to prepare freshly and use it on the same day.
- The percentages shown for the solvents indicate their volumetric ratio in the final prepared solution. If precipitation or phase separation occurs during preparation, heat and/or sonication can be used to aid dissolution.
Add each solvent one by one: 10% DMSO 40% PEG300 5% Tween-80 45% Saline
Solubility: ≥ 2.5 mg/mL (5.11 mM); Clear solution
This protocol yields a clear solution of ≥ 2.5 mg/mL (saturation unknown).
Taking 1 mL working solution as an example, add 100 μL DMSO stock solution (25.0 mg/mL) to 400 μL PEG300, and mix evenly; then add 50 μL Tween-80 and mix evenly; then add 450 μL Saline to adjust the volume to 1 mL.
Preparation of Saline: Dissolve 0.9 g sodium chloride in ddH₂O and dilute to 100 mL to obtain a clear Saline solution.
Add each solvent one by one: 10% DMSO 90% (20% SBE-β-CD in Saline)
Solubility: ≥ 2.5 mg/mL (5.11 mM); Clear solution
This protocol yields a clear solution of ≥ 2.5 mg/mL (saturation unknown).
Taking 1 mL working solution as an example, add 100 μL DMSO stock solution (25.0 mg/mL) to 900 μL 20% SBE-β-CD in Saline, and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C, storage for one week): 2 g SBE-β-CD powder is dissolved in 10 mL Saline, completely dissolve until clear.
Please enter the basic information of animal experiments:
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Recommended: Prepare an additional quantity of animals to account for potential losses during experiments.
Please enter your animal formula composition:
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%DMSO +
Recommended: Keep the proportion of DMSO in working solution below 2% if your animal is weak.
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%+
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+%Tween-80 + +
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%Saline +
The co-solvents required include: DMSO, . All of co-solvents are available by MedChemExpress (MCE). , Tween 80. All of co-solvents are available by MedChemExpress (MCE).
Working solution concentration: 0.22 mg/mL
Method for preparing stock solution: mg drug dissolved in μL DMSO. Stock solution concentration: mg/mL.
1. Take μL DMSO stock solution;
2. Add μL .
μL , mix evenly;
3. Then add μL Tween 80, mix evenly;
4. Then add μL
Please ensure that the stock solution in the first step is dissolved to a clear state, and add co-solvents in sequence. You can use ultrasonic heating (ultrasonic cleaner, recommended frequency 20-40 kHz), vortexing, etc. to assist dissolution.
Purity & Documentation
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Data Sheet (280 KB)
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SDS (251 KB)
- English - EN (251 KB)
- Français - FR (251 KB)
- Deutsch - DE (251 KB)
- Norwegian - NO (251 KB)
- Español - ES (251 KB)
- Swedish - SV (251 KB)
- Italian - IT (251 KB)
- Korean - KR (251 KB)
- Portuguese - PT (251 KB)
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Handling Instructions (2659 KB)
References
[1]. Kubeš J, et al. Topobexin targets the Topoisomerase II ATPase domain for beta isoform-selective inhibition and anthracycline cardioprotection. Nat Commun. 2025;16(1):4928. Published 2025 May 28. [Content Brief]
[2]. Kosić M, et al. Drug Repositioning in Doxorubicin-Induced Cardiotoxicity Protection. Int J Mol Sci. 2025;26(20):10130. Published 2025 Oct 17. [Content Brief]
Complete Stock Solution Preparation Table
Please refer to the solubility information to select the appropriate solvent. Once prepared, please aliquot and store the solution to prevent product inactivation from repeated freeze-thaw cycles.
Storage method and period of stock solution: -80°C, 6 months; -20°C, 1 month. When stored at -80°C, please use it within 6 months. When stored at -20°C, please use it within 1 month.
| Optional Solvent | Concentration Solvent Mass | 1 mg | 5 mg | 10 mg | 25 mg |
|---|---|---|---|---|---|
| DMSO | 1 mM | 2.0424 mL | 10.2122 mL | 20.4244 mL | 51.0611 mL |
| 5 mM | 0.4085 mL | 2.0424 mL | 4.0849 mL | 10.2122 mL | |
| 10 mM | 0.2042 mL | 1.0212 mL | 2.0424 mL | 5.1061 mL | |
| 15 mM | 0.1362 mL | 0.6808 mL | 1.3616 mL | 3.4041 mL | |
| 20 mM | 0.1021 mL | 0.5106 mL | 1.0212 mL | 2.5531 mL | |
| 25 mM | 0.0817 mL | 0.4085 mL | 0.8170 mL | 2.0424 mL | |
| 30 mM | 0.0681 mL | 0.3404 mL | 0.6808 mL | 1.7020 mL | |
| 40 mM | 0.0511 mL | 0.2553 mL | 0.5106 mL | 1.2765 mL | |
| 50 mM | 0.0408 mL | 0.2042 mL | 0.4085 mL | 1.0212 mL |
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