| Size | Price | Stock | Qty |
|---|---|---|---|
| 1mg |
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| 5mg | |||
| Other Sizes |
| Targets |
Kd: 2.8 μM (RING1B-BMI1f)[1].
PRC1 (Polycomb Repressive Complex 1). RB-3 directly binds to the RING1B-BMI1 complex with a Kd of 2.8 uM. It targets the E3 ligase activity of PRC1, which catalyzes the monoubiquitination of histone H2A at lysine 119 (H2AK119ub). |
|---|---|
| ln Vitro |
Leukemia cell lines and primary acute myeloid leukemia (AML) samples undergo differentiation in response to RB-3, which also lowers the global level of H2A ubiquitination[1]. H2A ubiquitination is inhibited by RB-3, with an IC50 of 1.6 μM[1]. PRC1 and interferes with nucleosome interaction[1]. In a mixed lineage leukemia (MLL)-eleven nineteen leukemia (ENL) model, RB-3 inhibits colony formation[1].
RB-3 binds directly to the RING1B-BMI1 complex with a Kd of 2.8 uM. It decreases the global level of H2A ubiquitination with an IC50 of 1.6 uM. RB-3 induces differentiation in leukemia cell lines and primary acute myeloid leukemia (AML) samples. In a mixed lineage leukemia (MLL)-ENL model, RB-3 inhibits colony formation and increases C/EBPalpha-p42 protein levels in a dose-dependent manner (tested at 6, 12, and 25 uM). |
| ln Vivo |
In a mixed lineage leukemia (MLL)-ENL mouse model, RB-3 inhibits colony formation, suggesting in vivo efficacy in suppressing leukemic cell growth. By reducing H2A ubiquitination and promoting differentiation, RB-3 represents a valuable chemical tool for studying PRC1 biology in cancer, particularly in hematopoietic malignancies where PRC1 is frequently dysregulated. Detailed in vivo protocols are available in the primary literature.
|
| Enzyme Assay |
The binding affinity of RB-3 to RING1B-BMI1 is determined using surface plasmon resonance (SPR). Recombinant RING1B-BMI1 complex is immobilized on a sensor chip, and RB-3 is flowed over at increasing concentrations (0.1-100 uM). The association and dissociation rates are measured to calculate the Kd (2.8 uM). For functional assays, purified nucleosomes are incubated with PRC1 and a ubiquitin-charged E2 enzyme, and H2A ubiquitination is assessed by Western blot.
|
| Cell Assay |
Western Blot Analysis[1]
Cell Types: TEX cells. Tested Concentrations: 6, 12, 25 μM. Incubation Duration: 8d. Experimental Results: Dose-dependently increased C/EBPα-p42 protein levels. For cellular assays, leukemia cell lines (e.g., K562 or MLL-rearranged lines) or primary AML samples are treated with RB-3 (1-50 uM) for 24-96 hours. Global H2A ubiquitination levels are analyzed by Western blot using an antibody specific for H2AK119ub. Cell differentiation is assessed by flow cytometry using CD11b and CD14 markers. Colony formation is evaluated in methylcellulose-based assays. |
| Animal Protocol |
RB-3 can be administered intraperitoneally or orally in mouse xenograft models of MLL-rearranged leukemia. Doses are typically optimized based on PK/PD studies. Tumor burden is measured by bioluminescence imaging (if using luciferase-tagged cells) or by assessing spleen weight and white blood cell counts. At study termination, bone marrow and spleen cells are harvested for analysis of H2A ubiquitination and differentiation markers by flow cytometry and Western blot.
|
| ADME/Pharmacokinetics |
RB-3 has a molecular weight of 417.89 g/mol. It is soluble in DMSO at 100 mg/mL (239 mM). For in vivo use, it can be formulated in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% saline. The compound has moderate lipophilicity (LogP 5.9). The powder should be stored at -20degC, protected from moisture and light. Detailed PK parameters have not been extensively reported.
|
| Toxicity/Toxicokinetics |
Detailed toxicological data for RB-3 are not extensively reported in the supplier literature. In primary AML samples, RB-3 induces differentiation at concentrations up to 25 uM without overt cytotoxicity. As a research compound, it is not for human use. Standard safety precautions for handling research chemicals should be followed, including the use of gloves and eye protection.
|
| References | |
| Additional Infomation |
RB-3 is a first-in-class chemical probe for studying PRC1 function. It was identified through a high-throughput screen for compounds that induce differentiation in MLL-rearranged leukemia and described in Nature Chemical Biology in 2021. RB-3 is not an FDA-approved drug and is intended for research use only. It is particularly valuable for validating PRC1 as a therapeutic target in cancer.
|
| Molecular Formula |
C24H20CLN3O2
|
|---|---|
| Molecular Weight |
417.89
|
| Exact Mass |
417.124
|
| CAS # |
2396639-11-3
|
| PubChem CID |
146315785
|
| Appearance |
White to light yellow solid powder
|
| LogP |
5.9
|
| Hydrogen Bond Donor Count |
4
|
| Hydrogen Bond Acceptor Count |
2
|
| Rotatable Bond Count |
4
|
| Heavy Atom Count |
30
|
| Complexity |
646
|
| Defined Atom Stereocenter Count |
0
|
| SMILES |
N1C(C2=CC=CC3=C2C=CN3)=C(C(C)C)C(C2=C(Cl)C=CC3=C2C=CN3)=C1C(O)=O
|
| InChi Key |
IUEFQUANJWCUNT-UHFFFAOYSA-N
|
| InChi Code |
InChI=1S/C24H20ClN3O2/c1-12(2)19-21(20-15-9-11-27-18(15)7-6-16(20)25)23(24(29)30)28-22(19)14-4-3-5-17-13(14)8-10-26-17/h3-12,26-28H,1-2H3,(H,29,30)
|
| Chemical Name |
3-(5-chloro-1H-indol-4-yl)-5-(1H-indol-4-yl)-4-propan-2-yl-1H-pyrrole-2-carboxylic acid
|
| HS Tariff Code |
2934.99.9001
|
| Storage |
Powder -20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month Note: Please store this product in a sealed and protected environment (e.g. under nitrogen), avoid exposure to moisture and light. |
| Shipping Condition |
Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)
|
| Solubility (In Vitro) |
DMSO: 100 mg/mL (239.30 mM)
|
|---|---|
| Solubility (In Vivo) |
Solubility in Formulation 1: ≥ 3.25 mg/mL (7.78 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 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 32.5 mg/mL clear DMSO stock solution to 400 μL of PEG300 and mix evenly; then add 50 μL of Tween-80 to the above solution and mix evenly; then add 450 μL of 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. Solubility in Formulation 2: ≥ 3.25 mg/mL (7.78 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (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 32.5 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly. (Please use freshly prepared in vivo formulations for optimal results.) |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 2.3930 mL | 11.9649 mL | 23.9297 mL | |
| 5 mM | 0.4786 mL | 2.3930 mL | 4.7859 mL | |
| 10 mM | 0.2393 mL | 1.1965 mL | 2.3930 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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