BSP16 is a potent orally bioactive interferon gene agonist (STING) agonist. BSP16 can selectively stimulate the STING pathway. BSP16 could be used in cancer-related research.

Physicochemical Properties

Molecular Formula	C16H18O5SE
Molecular Weight	369.271124362946
Exact Mass	370.031
CAS #	2727249-47-8
PubChem CID	164946677
Appearance	Typically exists as solid at room temperature
Hydrogen Bond Donor Count	1
Hydrogen Bond Acceptor Count	5
Rotatable Bond Count	7
Heavy Atom Count	22
Complexity	413
Defined Atom Stereocenter Count	1
SMILES	CC[C@H](CC(=O)C1=CC2=CC(=C(C=C2[Se]1)OC)OC)C(=O)O
InChi Key	BWQHPFYQJHFPHN-SECBINFHSA-N
InChi Code	InChI=1S/C16H18O5Se/c1-4-9(16(18)19)5-11(17)15-7-10-6-12(20-2)13(21-3)8-14(10)22-15/h6-9H,4-5H2,1-3H3,(H,18,19)/t9-/m1/s1
Chemical Name	(2R)-4-(5,6-dimethoxy-1-benzoselenophen-2-yl)-2-ethyl-4-oxobutanoic 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
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	BSP16, with EC50 values of 5.71 μM and 9.24 μM, respectively, can selectively stimulate the STING pathway in ISGRAW264.7 and ISG-THP1 cells[1]. In human and mouse cells, BSP16 (10, 25, 50 μM; 1, 3, 6 h) binds STING as a homodimer and strongly activates STING signaling[1]. The absorption, distribution, metabolism, excretion, and toxicity of BSP16 are all promising[1].
ln Vivo	BSP16 has an outstanding pharmacokinetic profile and is well-lerated (po, 50 mg/kg; iv, 5 mg/kg)[1]. Tumor regression and long-lasting antitumor immunity are brought about by BSP16 (oral, 15 and 30 mg/kg, q3d; oral, 20 mg/kg, q5d)[1].
Cell Assay	RT-PCR[1] Cell Types: ISG-THP1 cells Tested Concentrations: 10, 25, 50 μM Incubation Duration: 1, 3, 6 h Experimental Results: Robustly induced mRNA expression of target genes IFNβ, CXCL10, and IL6 in response to STING activation, in a time and concentration-dependent manner in ISGTHP1 cells. Western Blot Analysis[1] Cell Types: ISG-THP1 cells Tested Concentrations: 10, 25, 50 μM Incubation Duration: 1, 3, 6 h Experimental Results: Rapidly increased the phosphorylation of TBK1 and IRF3 in a concentration-dependent manner.
Animal Protocol	Animal/Disease Models: MC38 (colon carcinoma) syngeneic tumor model[1] Doses: 15, 30 mg/kg Route of Administration: po (oral gavage) q3d Experimental Results: demonstrated tolerated and excellent antitumor efficacy, experienced complete tumor regression (CR) after day 21. Resulted in robust induction of IFNB and IL6 (30 mg/kg). Animal/Disease Models: CT26 (colon carcinoma) tumor model[1] Doses: 20 mg/kg Route of Administration: po (oral gavage) q5d Experimental Results: demonstrated tolerated and induced tumor regression in all treated mice within 30 days. Led to a substantial elevation of IFNB in the plasma in CT26 bearing mice. Animal/Disease Models: Rats[1] Doses: 5 mg/kg, 50 mg/kg Route of Administration: oral and iv Experimental Results: compd. adm. Cmax(μg/mL) AUG0-∞(h*μg/mL) t1/2(h) Vss(L/kg) CL(L/h/kg) F(%) BSP16 po(50 mg/kg) 58.2 315.9 1.60 0.38 0.16 107 iv(5 mg/kg) 29.4 1.04 0.26 0.17
References	[1]. Discovery of Selenium-Containing STING Agonists as Orally Available Antitumor Agents. J Med Chem. 2022 Sep 7.

Solubility Data

Solubility (In Vitro)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

Solubility (In Vivo)

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples. Injection Formulations (e.g. IP/IV/IM/SC) Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline) *Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution. Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline) Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil) Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals). Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)] *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. Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline) Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline) Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline) Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil) Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline) Oral Formulations Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium) Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals). Oral Formulation 3: Dissolved in PEG400 Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose Oral Formulation 6: Mixing with food powders Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	2.7080 mL	13.5402 mL	27.0805 mL
	5 mM	0.5416 mL	2.7080 mL	5.4161 mL
	10 mM	0.2708 mL	1.3540 mL	2.7080 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.