EC359 is a specific, high-affinity and orally bioavailable leukemia inhibitory factor receptor (LIFR) inhibitor (antagonist) with a Kd of 10.2 nM that directly interacts with LIFR to effectively block LIF/ LIFR interactions.

Physicochemical Properties

Molecular Formula	C36H38F2O2
Molecular Weight	540.682537555695
Exact Mass	540.283
CAS #	2012591-09-0
PubChem CID	139600278
Appearance	Typically exists as solid at room temperature
LogP	6.5
Hydrogen Bond Donor Count	1
Hydrogen Bond Acceptor Count	4
Rotatable Bond Count	3
Heavy Atom Count	40
Complexity	1140
Defined Atom Stereocenter Count	5
SMILES	CC1=CC(=C(C(=C1)C)C2=CC=C(C=C2)[C@H]3C[C@]4([C@@H](CC[C@]4(C(C#C)(F)F)O)[C@H]5C3=C6CCC(=O)C=C6CC5)C)C
InChi Key	AHHXLJGAODIDAX-WQQPUSSASA-N
InChi Code	InChI=1S/C36H38F2O2/c1-6-36(37,38)35(40)16-15-31-29-13-11-26-19-27(39)12-14-28(26)33(29)30(20-34(31,35)5)24-7-9-25(10-8-24)32-22(3)17-21(2)18-23(32)4/h1,7-10,17-19,29-31,40H,11-16,20H2,2-5H3/t29-,30+,31-,34-,35-/m0/s1
Chemical Name	(8S,11R,13S,14S,17S)-17-(1,1-difluoroprop-2-ynyl)-17-hydroxy-13-methyl-11-[4-(2,4,6-trimethylphenyl)phenyl]-1,2,6,7,8,11,12,14,15,16-decahydrocyclopenta[a]phenanthren-3-one
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

Targets	Kd: 10.2 nM (leukemia inhibitory factor receptor)[1]
ln Vitro	In a dose-dependent way, EC359 (0-100 nM; 3 days) treatment decreases cell viability in BT-549, SUM-159, MDA-MB-231, MDA-MB-468, and HCC1806 cells[1]. Caspasese-3/7 activity and Annexin V-positive cells in MDA-MB-231 and BT-549 cells are markedly increased by EC359 (20 nM, 25 nM; 72 hours). TNBC cells undergo apoptosis when exposed to EC359, which inhibits invasion significantly[1]. Many known STAT3 target genes, including STAT1, TGFB1, JUNB, MCL-1, and others, have markedly decreased expression when exposed to EC359 (100 nM; 12 hours; BT549 cells)[1]. Significantly lessening STAT3 activation by LIF, OSM, and CNTF, EC359 (100 nM; 1 hour; MDA-MB-231 and BT-549 cells) therapy also does so. AKT, mTOR, S6, and ERK1/2 phosphorylation in MDA-MB231 and BT-549 cells is significantly reduced by EC359 therapy. Phosphorylation of proapoptotic p38MAPK in BT549 cells is likewise increased by EC359 treatment[1].
ln Vivo	Treatment with EC359 (5 mg/kg; subcutaneous injection; three days a week; for 25 days; female athymic nude mice) dramatically slowed the growth of the tumor. The mice's body weights in the EC359-treated groups do not vary, indicating that EC359 is not very toxic[1].
Cell Assay	Cell Viability Assay[1] Cell Types: BT-549, SUM-159, MDA-MB-231, MDA-MB-468, and HCC1806 cells Tested Concentrations: 0 nM, 1.5 nM, 12.5 nM, 25 nM, 50 nM, 100 nM Incubation Duration: 3 days Experimental Results: decreased cell viability in a dose-dependent manner. Apoptosis Analysis[1] Cell Types: MDA-MB-231 and BT-549 cells Tested Concentrations: 20 nM, 25 nM Incubation Duration: 72 hrs (hours) Experimental Results: Promoted apoptosis of TNBC cells. RT-PCR[1] Cell Types: BT549 cells Tested Concentrations: 100 nM Incubation Duration: 12 hrs (hours) Experimental Results: decreased the expression of several known STAT3 target genes. Western Blot Analysis [1] Cell Types: MDA-MB-231 and BT-549 cells Tested Concentrations: 100 nM Incubation Duration: 1 hour Experimental Results: Substantially decreased the LIF activation of STAT3, decreased the STAT3 activation by OSM and CNTF, diminished the phosphorylation of AKT, mTOR, S6, and ERK1/2 in both BT-549 and MDA-MB-231 cells and increased the phosphorylation of proapoptotic p38MAPK in BT549 cells.
Animal Protocol	Animal/Disease Models: 8weeks old female athymic nude mice with MDA-MB-231 cells[1] Doses: 5 mg/kg Route of Administration: subcutaneous (sc)injection; 3 days per week; for 25 days Experimental Results: Dramatically diminished the tumor progression.
References	[1]. Viswanadhapalli S, et al. EC359: A First-in-Class Small-Molecule Inhibitor for Targeting Oncogenic LIFR Signaling in Triple-Negative Breast Cancer. Mol Cancer Ther. 2019 Aug;18(8):1341-1354.

Solubility Data

Solubility (In Vitro)

DMSO : 125 mg/mL (231.19 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.08 mg/mL (3.85 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 20.8 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: ≥ 2.08 mg/mL (3.85 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 20.8 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	1.8495 mL	9.2476 mL	18.4952 mL
	5 mM	0.3699 mL	1.8495 mL	3.6990 mL
	10 mM	0.1850 mL	0.9248 mL	1.8495 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.