| Size | Price | Stock | Qty |
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| 1mg |
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| 5mg |
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| 10mg |
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| 50mg |
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| 100mg |
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| 250mg | |||
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| Other Sizes |
| Targets |
- RAD51 (IC50 = 1.2 μM for ATPase activity; IC50 = 0.9 μM for ssDNA binding)[2]
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|---|---|
| ln Vitro |
IBR2 exhibits inhibitory activity against RAD51. In IBR2-treated molds, homologous recombination repair is compromised, resulting in cell death, and RAD51 is rapidly degraded. The original IBR2's IC50 values fell between 12 and 20 μM for the majority of the tested mold lines. With an IC50 of 14.8 μM, IBR2 suppresses the growth of the triple-negative human breast cancer cell line MBA-MD-468 [1].
- Chronic myeloid leukemia (CML) cells (K562, imatinib-resistant K562-R): IBR2 inhibits cell proliferation in a concentration-dependent manner, with IC50 values of 3.5 μM (K562) and 4.2 μM (K562-R); combination with imatinib synergistically enhances cytotoxicity, reducing IC50 values of imatinib by 60% in K562-R cells[1] - RAD51 ATPase activity inhibition: IBR2 directly inhibits RAD51-mediated ATP hydrolysis with an IC50 of 1.2 μM, blocking the energy-dependent step of homologous recombination (HR) repair[2] - RAD51 DNA binding inhibition: IBR2 disrupts RAD51 binding to single-stranded DNA (ssDNA) with an IC50 of 0.9 μM, preventing formation of RAD51 nucleoprotein filaments[2] - HR repair suppression: IBR2 (2-5 μM) reduces HR efficiency in DR-GFP reporter assay (HeLa cells), decreasing GFP-positive cells by 55-70%; it also reduces ionizing radiation (IR)-induced RAD51 nuclear foci formation and γH2AX focus resolution in K562 cells[1][2] - Apoptosis induction: IBR2 (5 μM) induces apoptosis in K562-R cells, increasing Annexin V-positive cells by 40% and activating caspase-3/7; it also upregulates p53 and p21 expression, leading to G2/M cell cycle arrest[1] |
| ln Vivo |
- Nude mice bearing K562-R xenografts: Intraperitoneal administration of IBR2 (50 mg/kg, 3 times/week for 3 weeks) significantly inhibits tumor growth, reducing tumor volume by 65% and tumor weight by 62% compared to vehicle control[1]
- Combination therapy in K562-R xenografts: IBR2 (30 mg/kg) combined with imatinib (25 mg/kg) achieves 80% tumor growth inhibition, which is significantly higher than monotherapy with either drug (P < 0.01)[1] - Pharmacodynamic marker modulation: IBR2 treatment reduces RAD51 nuclear foci and increases γH2AX accumulation in xenograft tissues, confirming in vivo suppression of HR repair[1] |
| Enzyme Assay |
- RAD51 ATPase activity assay: Recombinant RAD51 protein is preincubated with IBR2 (0.1-20 μM) for 30 minutes at 37°C. ATP and ssDNA are added to initiate the reaction, which is incubated for another 60 minutes. Free phosphate generated from ATP hydrolysis is detected using a malachite green assay kit. IC50 values are calculated by nonlinear regression of inhibition curves[2]
- RAD51 ssDNA binding assay: Fluorescein-labeled ssDNA is mixed with recombinant RAD51 and various concentrations of IBR2 (0.1-10 μM). The mixture is incubated at 25°C for 45 minutes, and fluorescence polarization is measured using a microplate reader. The ability of IBR2 to displace RAD51 from ssDNA is quantified, and IC50 values are determined[2] |
| Cell Assay |
- Cell proliferation assay: K562 and K562-R cells are seeded in 96-well plates and cultured overnight. Cells are treated with IBR2 (0.5-20 μM) alone or in combination with imatinib (0.1-10 μM) for 72 hours. CCK-8 reagent is added, and absorbance at 450 nm is measured to calculate cell viability and IC50 values[1]
- HR repair efficiency assay: HeLa cells stably expressing DR-GFP reporter are transfected with I-SceI plasmid to induce double-strand breaks (DSBs). Cells are treated with IBR2 (2-5 μM) for 24 hours, and GFP-positive cells (indicating successful HR repair) are quantified by flow cytometry[1][2] - Immunofluorescence assay for RAD51/γH2AX foci: K562 cells are treated with IBR2 (3 μM) for 24 hours, followed by 2 Gy IR. Cells are fixed, permeabilized, and stained with anti-RAD51 and anti-γH2AX antibodies. Foci are visualized under a confocal microscope, and the number of foci per cell is counted[1] - Apoptosis and cell cycle assay: K562-R cells are treated with IBR2 (5 μM) for 48 hours. Cells are stained with Annexin V-FITC/PI for apoptosis detection, or with propidium iodide for cell cycle analysis, both measured by flow cytometry. Western blot is used to detect p53, p21, and cleaved caspase-3/7 expression[1] |
| Animal Protocol |
- Imatinib-resistant CML xenograft model: Nude mice are subcutaneously inoculated with K562-R cells (2×10⁶ cells/mouse) to establish xenografts. When tumors reach 100-120 mm³, mice are randomly divided into 4 groups: vehicle control, IBR2 monotherapy (50 mg/kg), imatinib monotherapy (25 mg/kg), and combination therapy (IBR2 30 mg/kg + imatinib 25 mg/kg). Drugs are administered via intraperitoneal injection 3 times per week for 3 weeks. Tumor volume (measured every 2 days) and body weight (measured weekly) are recorded. After sacrifice, tumors are excised, weighed, and processed for immunohistochemistry (RAD51, γH2AX staining)[1]
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| References | |
| Additional Infomation |
IBR2 is a small molecule inhibitor of RAD51 that targets the ATPase domain and ssDNA binding region of RAD51 [2]. IBR2’s anti-CML effect is achieved by inhibiting homologous recombination (HR) repair, which makes CML cells (especially imatinib-resistant clones) more sensitive to double-strand breaks (DSB) accumulation and apoptosis [1]. IBR2 overcomes imatinib resistance by targeting the HR repair pathway, which is upregulated in imatinib-resistant CML cells to cope with DSB-induced stress [1]. Molecular modeling shows that IBR2 binds to the ATP-binding pocket of RAD51 and forms hydrogen bonds with key residues (Lys133, Glu105), thereby blocking ATP hydrolysis [2].
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| Molecular Formula |
C24H20N2O2S
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|---|---|
| Molecular Weight |
400.493
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| Exact Mass |
400.124
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| CAS # |
313526-24-8
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| PubChem CID |
4664423
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| Appearance |
Off-white to pink solid powder
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| LogP |
4.5
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| Hydrogen Bond Donor Count |
1
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| Hydrogen Bond Acceptor Count |
3
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| Rotatable Bond Count |
4
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| Heavy Atom Count |
29
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| Complexity |
694
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| Defined Atom Stereocenter Count |
0
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| SMILES |
O=S(N1C(C2=CNC3=C2C=CC=C3)C4=C(C=CC=C4)C=C1)(CC5=CC=CC=C5)=O
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| InChi Key |
YCOHEPDJLXZVBZ-UHFFFAOYSA-N
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| InChi Code |
InChI=1S/C24H20N2O2S/c27-29(28,17-18-8-2-1-3-9-18)26-15-14-19-10-4-5-11-20(19)24(26)22-16-25-23-13-7-6-12-21(22)23/h1-16,24-25H,17H2
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| Chemical Name |
2-benzylsulfonyl-1-(1H-indol-3-yl)-1H-isoquinoline
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| HS Tariff Code |
2934.99.9001
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| Storage |
Powder -20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month |
| Shipping Condition |
Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)
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| Solubility (In Vitro) |
DMSO : ≥ 100 mg/mL (~249.69 mM)
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|---|---|
| Solubility (In Vivo) |
Solubility in Formulation 1: ≥ 2.5 mg/mL (6.24 mM) (saturation unknown) in 10% DMSO + 40% PEG300 +5% Tween-80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 + to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. (Please use freshly prepared in vivo formulations for optimal results.) |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 2.4969 mL | 12.4847 mL | 24.9694 mL | |
| 5 mM | 0.4994 mL | 2.4969 mL | 4.9939 mL | |
| 10 mM | 0.2497 mL | 1.2485 mL | 2.4969 mL |
*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.
Calculation results
Working concentration： mg/mL；
Method for preparing DMSO stock solution： mg drug pre-dissolved in μL DMSO (stock solution concentration mg/mL). Please contact us first if the concentration exceeds the DMSO solubility of the batch of drug.
Method for preparing in vivo formulation:：Take μL DMSO stock solution, next add μL PEG300, mix and clarify, next addμL Tween 80, mix and clarify, next add μL ddH2O，mix and clarify.
(1) Please be sure that the solution is clear before the addition of next solvent. Dissolution methods like vortex, ultrasound or warming and heat may be used to aid dissolving.
(2) Be sure to add the solvent(s) in order.
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