RB-3 is an inhibitor (blocker/antagonist) of PRC1 and binds to RING1B-BMI1f with Kd of 2.8 μM.

Physicochemical Properties

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)

Biological Activity

Targets	Kd: 2.8 μM (RING1B-BMI1f)[1].
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].
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.
References	[1]. Small-molecule inhibitors targeting Polycomb repressive complex 1 RING domain. Nat Chem Biol. 2021 Jul;17(7):784-793.

Solubility Data

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.