PFI-4 is a novel, potent, cell permeable and selective inhibitor of bromodomain and PHD finger-containing protein 1 (BRPF1) with antineoplastic activity. It inhibits BRPF1 with an IC50 of 80 nM. PFI-4 aacts by specifically binding to BRPF1B with a Kd =13 nM as determined by ITC. It reduces recovery time in triple BRD cell construct in FRAP and is potent in cells with IC50 of 250nM, while showing no effect on BRPF1A. BRPF1A may act as dominant negative isoform of BRPF1 generated by alternative splicing. BRPF1 exists in 2 different isoforms: BRPF1A and BRPF1B. A residue insertion in the ZA loop of BRPF1A prevents binding to acetylated histone peptides. BRPF1A may act as dominant negative isoform of BRPF1 generated by alternative splicing.

Physicochemical Properties

Molecular Formula	C21H24N4O3
Molecular Weight	380.44
Exact Mass	380.184
CAS #	900305-37-5
Related CAS #	900305-37-5
PubChem CID	40642506
Appearance	Light green to green solid powder
Density	1.3±0.1 g/cm3
Boiling Point	512.1±50.0 °C at 760 mmHg
Flash Point	263.5±30.1 °C
Vapour Pressure	0.0±1.3 mmHg at 25°C
Index of Refraction	1.649
LogP	1.79
Hydrogen Bond Donor Count	1
Hydrogen Bond Acceptor Count	4
Rotatable Bond Count	4
Heavy Atom Count	28
Complexity	594
Defined Atom Stereocenter Count	0
InChi Key	QCIJLRJBZDBVDB-UHFFFAOYSA-N
InChi Code	InChI=1S/C21H24N4O3/c1-23-17-12-15(22-20(26)14-8-4-5-9-19(14)28-3)16(25-10-6-7-11-25)13-18(17)24(2)21(23)27/h4-5,8-9,12-13H,6-7,10-11H2,1-3H3,(H,22,26)
Chemical Name	N-[2,3-Dihydro-1,3-dimethyl-2-oxo-6-(1-pyrrolidinyl)-1H-benzimidazol-5-yl]-2-methoxybenzamide
Synonyms	PFI 4; PFI4; PFI-4.
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
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

ln Vitro	PFI-4 (1.25 µM; 7 or 11 days) suppresses development of human osteoclasts[1].
ln Vivo
Cell Assay	Cell Viability Assay[1] Cell Types: Osteoclasts Tested Concentrations: 1.25 µM Incubation Duration: 7 or 11 days Experimental Results: Dramatically reduces MMP9 secretion in osteoclasts .
Animal Protocol
References	[1]. Selective Targeting of Bromodomains of the Bromodomain-PHD Fingers Family Impairs Osteoclast Differentiation. ACS Chem Biol. 2017 Oct 20;12(10):2619-2630. [2]. 1,3-Dimethyl Benzimidazolones Are Potent, Selective Inhibitors of the BRPF1 Bromodomain. (2014) ACS Med Chem Lett. 5(11):1190-1195.

Solubility Data

Solubility (In Vitro)

DMSO: 17 mg/mL (44.7 mM) Water:<1 mg/mL Ethanol:5 mg/mL (13.1 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 1 mg/mL (2.63 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 10.0 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: ≥ 1 mg/mL (2.63 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in 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 10.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution. Solubility in Formulation 3: ≥ 1 mg/mL (2.63 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 10.0 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	2.6285 mL	13.1427 mL	26.2854 mL
	5 mM	0.5257 mL	2.6285 mL	5.2571 mL
	10 mM	0.2629 mL	1.3143 mL	2.6285 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.