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Catalog No.S1155 Synonyms: NSC 74859

142 publications

S3I-201 Chemical Structure

CAS No. 501919-59-1

S3I-201 (NSC 74859) shows potent inhibition of STAT3 DNA-binding activity with IC50 of 86 μM in cell-free assays, and low activity towards STAT1 and STAT5.

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10mM (1mL in DMSO) USD 98 In stock
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Selleck's S3I-201 has been cited by 142 publications

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Description S3I-201 (NSC 74859) shows potent inhibition of STAT3 DNA-binding activity with IC50 of 86 μM in cell-free assays, and low activity towards STAT1 and STAT5.
Features A chemical probe inhibitor of Stat3 activity.
STAT3 [1]
(Cell-free assay)
86 μM
In vitro

S3I-201 inhibits growth and induces apoptosis preferentially in tumor cells that contain persistently activated Stat3 by inhibiting Stat3·Stat3 complex formation and Stat3 DNA-binding and transcriptional activitie. Moreover, S3I-201 also inhibits the expression of the Stat3-regulated genes encoding cyclin D1, Bcl-xL, and survivin. [1] S3I-201 inhibits breast carcinoma MDA-MB-435, MDA-MB-453 and MDA-MB-231 cell lines with IC50 of 100 μM. In addition, the cells with impaired TGF-β signaling are four times as sensitive to the STAT3 inhibitor S3I-201. [2] A recent study shows that S3I-201 potentiates the antiproliferative effect of cetuximab in HepG2 and Huh-7 cells via the STAT3 signalling pathway. [3]

Cell Data
Cell Lines Assay Type Concentration Incubation Time Formulation Activity Description PMID
NCI-N87R NEPhRZVHfW6ldHnvckBCe3OjeR?= Mo\1OVAh|ryP NIC1dGMyOC14MDDk MYTpcohq[mm2czDTWGFVOyCjY4Tpeol1gQ>? MorpNlU{Ojd3NkG=
GH3 NUnzNYtmT3Kxd4ToJGlvcGmkaYTpc44hSXO|YYm= MnvNOVAuOTJ3IN88US=> NWHJTWFqPzJiaB?= MmHTZZR1\W63YYTld{B1cGViY3XscEBoem:5dHigbY4h[SCmb4PlMYRmeGWwZHXueEBu[W6wZYK= MXGyOVc4PDVyMx?=
GC  MV\Hdo94fGhiSX7obYJqfGmxbjDBd5NigQ>? MkmyOVAuOTJ3IN88US=> M3PGVlczKGh? NFPad|VifHSnboXheIV{KHSqZTDj[YxtKGe{b4f0bEBqdiCjIHTvd4Uu\GWyZX7k[Y51KG2jbn7ldi=> M4q3flI2Pzd2NUCz
H460  NXLoN|ZKSXCxcITvd4l{KEG|c3H5 NIL4O5gyODEEoH7N NG\1N|gzPMLiaB?= MlnobY5lfWOnczDj[YxtKGGyb4D0c5NqeyClbz30doVifGWmIIfpeIghSkWcMkO1 M{jKRVI1PDd{NUO4
A459 MXXBdI9xfG:|aYOgRZN{[Xl? M4nsbFExOMLibl2= NFmzNZIzPMLiaB?= MXLpcoR2[2W|IHPlcIwh[XCxcITvd4l{KGOxLYTy[YF1\WRid3n0bEBDTVp{M{W= NITrTnQzPDR5MkWzPC=>
H460  NFe3d2NCeG:ydH;zbZMhSXO|YYm= MUixNFDDqG6P NFGwWW4zPMLiaB?= MmXm[Y5p[W6lZYOgZ4VtdCCmZXH0bEBkdy22cnXheIVlKHerdHigUHkzQTRyMEK= NX36RW5YOjR2N{K1N|g>
MT-2 NIrPVYRCeG:ydH;zbZMhSXO|YYm= M2i1c|c2NTNyMDFOwG0> MnnYNlQwPDhiaB?= Mmqxd5VxeHKnc4Pld{Bk\WyuIIDyc4xq\mW{YYTpc44hcW5iYTDkc5NmNWSncHXu[IVvfCCvYX7u[ZIh[W6mIHnu[JVk\XNiY3XscEBieG:ydH;zbZPDqA>? MnPFNlQxQTB7OUW=
HUT-102 NH\pNHpCeG:ydH;zbZMhSXO|YYm= NYTDUINOPzVvM{CwJO69VQ>? NFG1d48zPC92ODDo Ml;pd5VxeHKnc4Pld{Bk\WyuIIDyc4xq\mW{YYTpc44hcW5iYTDkc5NmNWSncHXu[IVvfCCvYX7u[ZIh[W6mIHnu[JVk\XNiY3XscEBieG:ydH;zbZPDqA>? M2\oNFI1ODlyOUm1
U373  NV\6eWhST3Kxd4ToJGlvcGmkaYTpc44hSXO|YYm= NIO5eZAyOjVizszN MXGyOEBp MXjEUXNQ MULkbZNzfXC2czDTWGFVOyC|aXfuZYxqdmdiYX7kJJBzd2yrZnXyZZRqd25? MlG3NlQxPzB6MkC=
T-cell  MWDHdo94fGhiSX7obYJqfGmxbjDBd5NigQ>? NIDabodKSzVyPUWwJO69VQ>? NVPhTIplOjRyNki3N|E>
H1299 MYHGeY5kfGmxbjDBd5NigQ>? NWixVXE6PTBxMUCwJO69VQ>? M2Dyc|Q5KGh? M3z6XJN2eHC{ZYPz[ZMhdWmULUmyZUBmgHC{ZYPzbY9vKGSxc3Wt[IVx\W6mZX70cJk> MXSyN|gzODJ3NB?=
PLC/PRF/5  Mn2wS5Jwf3SqIFnubIljcXSrb36gRZN{[Xl? NWDteVR{OTByIH7N MVS0PEBp NUPCbWdDTE2VTx?= MkfibY5pcWKrdIOgeIhmKEmOLU[gd5RqdXWuYYTpc44heHKxbX;0[YQh[2WubDDwdo9tcW[ncnH0bY9v NF3IR5ozOzN4NEO4PS=>
Huh7 NYL0XXRNT3Kxd4ToJGlvcGmkaYTpc44hSXO|YYm= NWe3[oN1OTByIH7N Ml3iOFghcA>? MX;EUXNQ NI[1[2dqdmirYnn0d{B1cGViSVytOkB{fGmvdXzheIlwdiCycn;tc5Rm\CClZXzsJJBzd2yrZnXyZZRqd25? NFjGRpkzOzN4NEO4PS=>
HUVEC  Ml\XSpVv[3Srb36gRZN{[Xl? MXSwMlUuOjBizszN NXm3dmV5OjRiaB?= NH:2TJJFVVOR NVHjT3Rze3WycILld5NmeyC2aHWgbJlxd3irYT3pcoR2[2WmIHHjZ5VufWyjdHnvckBw\iCKSV[tNe6y NHW1c20zOTV{M{W1PS=>
 U-373 MG MnrXR5l1d3SxeHnjbZR6KEG|c3H5 NYXQSnE{Oy9zMDFOwG0> MlW5NlQhcA>? M2rOU5Jm\HWlZYOgSm4u|rNvaX7keYNm\CClZXzsJI5mfXKxdH;4bYNqfHl? MX:yNFg5QDRzNh?=
MDA-MB-231 NIfKdGRIem:5dHigTY5pcWKrdHnvckBCe3OjeR?= M1zuOFczKGh? M4HlWmlEPTExvK6xNFAh|ryP M2nXVlIxODd{NkWy
SK-BR-3 NI\wN3BIem:5dHigTY5pcWKrdHnvckBCe3OjeR?= MnHpO|IhcA>? NUXE[VhnUUN3MP-8olExOCEQvF2= MVqyNFA4OjZ3Mh?=
PANC-1 MUDHdo94fGhiSX7obYJqfGmxbjDBd5NigQ>? MYC3NkBp M2n3PGlEPTExvK6xNFAh|ryP NVvudlBXOjByN{K2OVI>
HPAC NV;ZclR{T3Kxd4ToJGlvcGmkaYTpc44hSXO|YYm= NVnm[ZZzPzJiaB?= M2\jemlEPTExvK6xNFAh|ryP MXGyNFA4OjZ3Mh?=
U87 NUfCO481T3Kxd4ToJGlvcGmkaYTpc44hSXO|YYm= NG[3fIw4OiCq NU\rVWhXUUN3ME21OU4yKM7:TR?= NEPjfo4zODB5Mk[1Ni=>
U373  MV\Hdo94fGhiSX7obYJqfGmxbjDBd5NigQ>? NILZbGg4OiCq M122[GlEPTB;NUKuOUDPxE1? M4S5TFIxODd{NkWy

... Click to View More Cell Line Experimental Data

Methods Test Index PMID
Western blot
STAT3 / p-STAT3 / Cyclin D1 / Bcl-2 / Nanog / OCT4 / ALDH1 / CD44; 

PubMed: 26556875     

Western blotting shows S3I-201 treatment decrease Cyclin D1, Bcl2 and self-renewal marker Nanog, OCT4, ALDH1, and CD44 in a dose dependent manner. Data shown are representative of three individual experiments.


PubMed: 28605599     

The expression level of PD-L1 was measured by Western blotting in a head and neck squamous cell carcinoma cell line (Cal 27 and FaDu), with and without S3I-201. β-Actin was used as the internal protein loading control. PD-L1, programmed death 1 ligand; STAT, signal transducers and activators of transcription; p-STAT3, phosphorylated STAT3.

26556875 28605599

PubMed: 26556875     

Immunoflurosece shows S3I-201 reduce nuclear expression of p-STAT3Tyr705 by confocal microscope. 

Oct4 / Twist ; 

PubMed: 27521216     

Suppression of Oct4 and Twist expression was shown in TW01 CD44/CD24 co-overexpressed cells and CSCs after S3I-201 treatment. Scale bars indicate 20 μm.

26556875 27521216
Growth inhibition assay
Cell viability; 

PubMed: 26813676     

The STAT3 inhibitor (S3I-201) decreases cellular proliferation in HTLV-I/ATL-lines. Cells were treated with 0, 12.5, 25, or 50 μM S3I-201 or dimethyl sulfoxide (DMSO) for 72 hours. The average growth curve is representative of the percentage of proliferation between S3I-201 and DMSO-treated cells. Each cell line was treated at least twice for standard deviation. 1185 (-IL2) cells were washed in phosphate-buffered saline and resuspended in media without IL2, followed by treatment with S3I-201 for 72 hours.

In vivo S3I-201 (5 mg/kg, i.v. every 2 or every 3 days) shows the antitumor efficacy in mouse models with human breast tumor xenografts that harbor constitutively active Stat3. [1] S3I-201 treatment reduces Varicella-zoster virus (VZV) replication on the basis of the bioluminescence signal and the number of positive skin xenografts compared with DMSO-treated mice by inhibiting STAT3 phosphorylation. [4]


Kinase Assay:[1]
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In vitro Stat3 DNA-binding assay and EMSA analysis :

Briefly, 100 mL of biotinyl-e-Ac-EPQpYEEIEL-OH (in 50 mM Tris/150 mM NaCl, pH 7.5) is added to each well of streptavidin-coated 96-well microtiter plates and incubated with shaking at 4 °C overnight. Then plates are rinsed with PBS/Tween 20 and then two times with 200 mL of BSA-T-PBS (0.2% BSA/0.1% Tween 20/PBS). Then 50 mL of Lck-SH2-GST fusion protein (6.4 ng/ml in BSA-T-PBS) is added to each well of the 96-well plate in the presence and absence of 50 mL of S3I-201 (for 30 and 100 mM final concentrations), and the plate is shaken at room temperature for 4 hours. After solutions are removed, each well is rinsed four times with BSA-T-PBS (200 mL), and 100 mL of polyclonal rabbit anti-GST antibody (100 ng/mL in BSA-T-PBS) is added to each well and incubated at 4 °C overnight. After washing with BSA-T-PBS, 100 mL of 200 ng/mL BSA-T-PBS horseradish peroxidase-conjugated mouse anti-rabbit antibody is added to each well and incubated for 45 minutes at room temperature. After four washing steps with BSA-T-PBS and three washing steps with PBS-T, 100 mL of peroxidase substrate is added to each well and incubated for 5-15 minutes. The peroxidase reaction is stopped by adding 100 mL of 1 M sulfuric acid solution, and absorbance is read at 450 nm with an ELISA plate rea
Cell Research:[2]
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  • Cell lines: MDA-MB-435, MDA-MB-453 and MDA-MB-231 cells lines
  • Concentrations: ~ 250 μM
  • Incubation Time: 72 hours
  • Method: The MTT assay is based on the conversion of the yellow tetrazolium salt MTT to purple formazan crystals by metabolically active cells. The MTT assay provides a quantitative determination of viable cells. Cells are seeded in 96-well microplates in complete culture medium in the absence or presence of increasing serial dosages of S3I-201 as indicated. At 72 hours after culture, the number of viable cells is measured by adding 100 μL/well of 2 mg/mL MTT solution. After 2 hours, the medium is removed, and the formazan crystals are dissolved by adding 100 μL dimethylsulfoxide per well. The absorbance is read at 590 nm with an enzyme-linked immunosorbent assay reader. Each treatment point is performed in 10 wells or sextuplicate.
    (Only for Reference)
Animal Research:[1]
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  • Animal Models: Human breast cancer MDA-MB-231 cells are injected s.c. into the left flank of athymic nu/nu mice.
  • Dosages: ≤5 mg/kg
  • Administration: Administered via i.v.
    (Only for Reference)

Solubility (25°C)

In vitro DMSO 73 mg/mL (199.8 mM)
Water Insoluble
Ethanol Insoluble
In vivo Add solvents to the product individually and in order(Data is from Selleck tests instead of citations):
5% DMSO+corn oil
For best results, use promptly after mixing.

* Please note that Selleck tests the solubility of all compounds in-house, and the actual solubility may differ slightly from published values. This is normal and is due to slight batch-to-batch variations.

Chemical Information

Molecular Weight 365.36


CAS No. 501919-59-1
Storage powder
in solvent
Synonyms NSC 74859
Smiles CC1=CC=C(C=C1)S(=O)(=O)OCC(=O)NC2=CC(=C(C=C2)C(=O)O)O

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Cell Lines Assay Type Concentration Incubation Time Formulation Activity Description PMID