Serpin B9-IN-1 (BTCA) is an inhibitor that specifically targets Serpin B9 (SB9); SB9 is a natural inhibitor of granzyme B (GrB) but may promote lung cancer cell metastasis to the bone marrow. SB9-overexpressing cancer cells promote proliferation and metastasis in an immune cell-dependent manner by binding to GrB. Inhibition of SB9 by Serpin B9-IN-1 significantly suppresses immunotherapy of lung cancer bone metastasis (LCBM) in the caudal artery (CA) mouse model.

Physicochemical Properties

Molecular Formula	C8H5NO3
Molecular Weight	163.13
CAS #	154235-77-5
PubChem CID	22245938
Appearance	Light brown to brown solid powder
Density	1.5±0.1 g/cm3
Boiling Point	350.1±15.0 °C at 760 mmHg
Flash Point	165.5±20.4 °C
Vapour Pressure	0.0±0.8 mmHg at 25°C
Index of Refraction	1.661
LogP	1.27
Hydrogen Bond Donor Count	1
Hydrogen Bond Acceptor Count	4
Rotatable Bond Count	1
Heavy Atom Count	12
Complexity	195
Defined Atom Stereocenter Count	0
SMILES	O1C=NC2C=CC(C(=O)O)=CC1=2
Synonyms	BTCA
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	IC50: Serpin B9
ln Vivo	Serpin B9-IN-1 (BTCA) inhibits bone metastasis (BM) in multiple tumor metastasis models. Serpin B9-IN-1 (50 mg/kg/d; ip; 14 d) effectively reduced the survival rate and metastatic proportion of metastatic cancer cells in the mouse bone metastasis model injected with LLC1-BM3 via tail artery (CA)[1]. Serpin B9-IN-1 (300 μg/d; ip; 14 d) effectively delayed the average time to bone metastasis (BM) in the LLC1-BM3 cell group[1].
Animal Protocol	Animal/Disease Models: LLC1-BM3 Bone Metastatic Mouse Model by CA injections[1] Doses: 50 mg/kg Route of Administration: ip; followed after cancer cell injection, injection daily for 14 days Experimental Results: Reduced the survival rate and metastasis proportion of metastatic cancer cells Animal/Disease Models: LLC1-BM3-sr-ctrl Model in Mouse[1] Doses: 300 μg Route of Administration: ip; once daily for 14 days Experimental Results: Delayed the mean time to occurrence of bone metastasis (BM), and lowered the burden of BM in LLC1-BM3-shSB9 cells group.
References	[1]. Mass Spectrometry-Based Proteomics Identifies Serpin B9 as a Key Protein in Promoting Bone Metastases in Lung Cancer. Mol Cancer Res. 2024 Apr 2;22(4):402-414.

Solubility Data

Solubility (In Vitro)

DMSO : ~100 mg/mL (~613.01 mM; with ultrasonication)

Solubility (In Vivo)

Solubility in Formulation 1: 5 mg/mL (30.65 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 sonication. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 50.0 mg/mL clear DMSO stock solution and add it to 900 μL of 20% SBE-β-CD saline solution and mix well. 2 g SBE-β-CD (sulfobutyl ether β-cyclodextrin) powder is diluted to 10 mL of saline and completely dissolved until clear and transparent. Solubility in Formulation 2: 5 mg/mL (30.65 mM) in 50% PEG300 50% Saline (add these co-solvents sequentially from left to right, and one by one),clear solution; with sonication.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	6.1301 mL	30.6504 mL	61.3008 mL
	5 mM	1.2260 mL	6.1301 mL	12.2602 mL
	10 mM	0.6130 mL	3.0650 mL	6.1301 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.