KH-3 is a potent inhibitor of the RNA-binding protein Hu antigen R (HuR) with IC50 of 0.35 μM. KH-3 has antiproliferation activity. KH-3 inhibits breast cancer/tumor cell invasion and delays lung colony formation by interfering with HuR-FOXQ1 mRNA interaction.

Physicochemical Properties

Molecular Formula	C21H22N2O4S2
Molecular Weight	430.54
Exact Mass	430.102
CAS #	1215115-03-9
PubChem CID	45138018
Appearance	Off-white to light yellow solid powder
LogP	4.4
Hydrogen Bond Donor Count	3
Hydrogen Bond Acceptor Count	6
Rotatable Bond Count	6
Heavy Atom Count	29
Complexity	703
Defined Atom Stereocenter Count	0
SMILES	C(NO)(=O)/C=C/C1SC2=CC=C(NS(C3=CC=C(C(C)(C)C)C=C3)(=O)=O)C=C2C=1
InChi Key	RIYPLPNXICDUCS-YRNVUSSQSA-N
InChi Code	InChI=1S/C21H22N2O4S2/c1-21(2,3)15-4-8-18(9-5-15)29(26,27)23-16-6-10-19-14(12-16)13-17(28-19)7-11-20(24)22-25/h4-13,23,25H,1-3H3,(H,22,24)/b11-7+
Chemical Name	(E)-3-[5-[(4-tert-butylphenyl)sulfonylamino]-1-benzothiophen-2-yl]-N-hydroxyprop-2-enamide
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

ln Vitro	KH-3 (0-100 μM; 48 hours; human breast cancer cell lines) reduces the development of breast cancer cells in a dose-dependent manner while blocking HuR function via lowering Bcl-2, Mis2, and XIAP mRNA levels [1]. In a dose-dependent manner, KH-3 (0-10 μM; 0-24 hours; MDA-MB-231 and SUM159 cells) suppresses the migration and invasion of breast cancer cells [1]. KH-3 (0-10 μM; MDA-MB-231 and SUM159 cells) decreases the quantity of HuR protein brought down by biotinylated AREFOXQ1 RNA oligomers and prevents HuR from interacting with FOXQ1 mRNA [1].
ln Vivo	KH-3 inhibits the growth and metastasis of breast cancer in vivo when given intraperitoneally to female athymic NCr-nu/nu and BALB/c mice three times a week for three weeks at a dose of 100 mg/kg [1].
Cell Assay	Western Blot analysis [1] Cell Types: MDA-MB-231 Cell Tested Concentrations: 5 and 10 μM Incubation Duration: 48 hrs (hours) Experimental Results: Bcl-2, Msi2 and XIAP protein expression levels were diminished.
Animal Protocol	Animal/Disease Models: Female athymic NCr-nu/nu (nude) mice orthotopically transplanted with MDA-MB-231 and balb/c (Bagg ALBino) mouse orthotopically transplanted with MDA-MB-231 [1] Doses: 100 mg/kg administered Method: intraperitoneal (ip) injection; intraperitoneal (ip) injection. Three times a week for three weeks. Experimental Results: Inhibited tumor growth, tumor regression by 60% after three weeks of treatment, and delayed the occurrence of lung metastasis. Reduces protein expression levels of HuR targets and induces E-cadherin expression in tumor tissues.
References	[1]. Targeting the interaction between RNA-binding protein HuR and FOXQ1 suppresses breast cancer invasion and metastasis. Commun Biol. 2020 Apr 24;3(1):193.

Solubility Data

Solubility (In Vitro)

DMSO : ~100 mg/mL (~232.27 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.5 mg/mL (5.81 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 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. Solubility in Formulation 2: 2.5 mg/mL (5.81 mM) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication. 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 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.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	2.3227 mL	11.6133 mL	23.2266 mL
	5 mM	0.4645 mL	2.3227 mL	4.6453 mL
	10 mM	0.2323 mL	1.1613 mL	2.3227 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.