Entospletinib (GS-9973)

For research use only.

Catalog No.S7523

28 publications

Entospletinib (GS-9973) Chemical Structure

CAS No. 1229208-44-9

Entospletinib (GS-9973) is an orally bioavailable, selective Syk inhibitor with IC50 of 7.7 nM in a cell-free assay and showed 13- to >1000-fold cellular selectivity for Syk over other kinases(including Jak2, ckit, Flt3, Ret, KDR) as assessed by target protein phosphorylation or functional response.

Selleck's Entospletinib (GS-9973) has been cited by 28 publications

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Choose Selective Syk Inhibitors

Biological Activity

Description Entospletinib (GS-9973) is an orally bioavailable, selective Syk inhibitor with IC50 of 7.7 nM in a cell-free assay and showed 13- to >1000-fold cellular selectivity for Syk over other kinases(including Jak2, ckit, Flt3, Ret, KDR) as assessed by target protein phosphorylation or functional response.
Features Orally bioavailable Syk-selective inhibitor that has been tested in Phase II clinical trials for treatment of Haematological Malignancies.
Syk [1]
(Cell-free assay)
7.7 nM
In vitro

GS-9973 shows good bidirectional permeability across Caco-2 cell monolayers in vitro. In cells, GS-9973 also shows excellent selectivity for Syk, and potently inhibits BCR-mediated activation and proliferation of B-cells as well as immune-complex-stimulated cytokine production in monocytes. [1] The combination of idelalisib and GS-9973 synergistically inhibits CLL cell viability and further disrupts chemokine signaling. [2]

Cell Data
Cell Lines Assay Type Concentration Incubation Time Formulation Activity Description PMID
human MV411 cells  NUHRTpJxWHKxbHnm[ZJifGmxbjDhd5NigQ>? NEjnSIk4OiCq MnvTTY5pcWKrdHnvckBw\iCIbISzJIlvKGi3bXHuJG1XPDFzIHPlcIx{KGG|c3Xzd4VlKGG|IHHzd4V{e2WmIHHzJJBzd2yrZnXyZZRqd25iYX\0[ZIhPzJiaILzJIlv[3WkYYTpc44h[nlic4DlZ5Rzd3Cqb4TvcYV1enluIFXDOVA:OC5|Mkeg{txO MkHCQIEhfGG{Z3X0QUdg[myjbnunJIhz\WZ;J3j0eJB{Qi9xcIXicYVlNm6lYnmucoxuNm6raD7nc5YwOjR5N{m1NVQoRjJ2N{e5OVE1RC:jPh?=
C57BL/6 mouse bone marrow cells M2Lse2N6fG:2b4jpZ:Kh[XO|YYm= M1LzW|Qh\GG7cx?= NFvMV4REgXSxdH;4bYNqfHliYXfhbY5{fCCFNUfCUE83KG2xdYPlJIJwdmVibXHydo94KGOnbHzzJIF{e2W|c3XkJIF{KGe{b4f0bEBqdmirYnn0bY9vKHC{ZXnuZ5Vj[XSnZDDmc5IhPCCmYYnzJIZwdGyxd3XkJIJ6KFt|SG2teIh6dWmmaX7lJIFl\Gm2aX;uJI1m[XO3cnXkJIFnfGW{IEWgbJJ{KGK7IHLleIFxdGG2ZTDjc5VvfGmwZzDhcoFtgXOrczygTWM2OD1yLkW4NkDPxE1? MX28ZUB1[XKpZYS9K39jdGGwazegbJJm\j1paIT0dJM7Ny:ydXLt[YQvdmOkaT7ucI0vdmmqLnfvek8zPTZ|M{e0NUc,OjV4M{O3OFE9N2F-
Ramos cells NXnHbplDTnWwY4Tpc44h[XO|YYm= MV;Jcohq[mm2aX;uJI9nKFO7azDpckBidnSraIXtZY4hUWePLYP0bY12dGG2ZXSgbJVu[W5iUnHtc5Mh[2WubIOgZZN{\XO|ZXSgZZMh\GWlcnXhd4UhcW5iQlPSMY1m\GmjdHXkJGJNVkticHjvd5Bpd3K7bHH0bY9vKGK7IHPlcIx2dGG{IHHzd4F6NCCHQ{WwQVAvODJ4zszN MW[8ZUB1[XKpZYS9K39jdGGwazegbJJm\j1paIT0dJM7Ny:ydXLt[YQvdmOkaT7ucI0vdmmqLnfvek8zPDd5OUWxOEc,OjR5N{m1NVQ9N2F-
B-cells M2HhdWZ2dmO2aX;uJIF{e2G7 NIDTb3gyKGi{ NEfHVGpKdmirYnn0bY9vKG:oIGP5b{BqdiCjbIDoZWloVS2|dHnteYxifGWmIHj1cYFvKEJiY3XscJMh[XO|ZYPz[YQh[XNiY3XscEBxem:uaX\ldoF1cW:wIHHmeIVzKDFiaIKgbY5kfWKjdHnvckBjgSCobH;3JIN6fG:vZYTyfUwhTUN3ME2wMlA1Oc7:TR?= MYG8ZUB1[XKpZYS9K39jdGGwazegbJJm\j1paIT0dJM7Ny:ydXLt[YQvdmOkaT7ucI0vdmmqLnfvek8zPDd5OUWxOEc,OjR5N{m1NVQ9N2F-
B-cells MVLGeY5kfGmxbjDhd5NigQ>? M37QZ|EhcHJ? NWfRUm9vUW6qaXLpeIlwdiCxZjDTfYshcW5iYXzwbIFK\01vc4TpcZVt[XSnZDDoeY1idiCEIHPlcIx{KGG|c3Xzd4VlKGG|IFPEPFYh\XiycnXzd4lwdiCjZoTldkAyKGi{IHnuZ5Vj[XSrb36gZpkh\myxdzDjfZRwdWW2comsJGVEPTB;MD6xNlXPxE1? M17ScFxiKHSjcnfleF0oZ2KuYX7rK{BpemWoPTfoeJRxezpxL4D1Zo1m\C6wY3LpMo5tdS6waXiu[493NzJ2N{e5OVE1Lz5{NEe3PVUyPDxxYU6=
mast cells NIW4eldHfW6ldHnvckBie3OjeR?= MUixJIhz M{nrSGlvcGmkaYTpc44hd2ZiY1vpeEBqdiC|dHXtJINmdGxiZnHjeI9zNXO2aX31cIF1\WRiYn;u[UBu[XK{b4eg[IVzcX[nZDDtc5V{\SCvYYP0JINmdGy|IHHzd4V{e2WmIHHzJJBpd3OyaH;yfYxifGmxbjDh[pRmeiBzIHjyJIlv[3WkYYTpc44tKEWFNUC9NE41PDYQvF2= MYK8ZUB1[XKpZYS9K39jdGGwazegbJJm\j1paIT0dJM7Ny:ydXLt[YQvdmOkaT7ucI0vdmmqLnfvek8zPDd5OUWxOEc,OjR5N{m1NVQ9N2F-
TF1 MUDGeY5kfGmxbjDhd5NigQ>? NHq1PGkyKGi{ NHfj[oRKdmirYnn0bY9vKG:oIFrhb|IhcW5iZYL5eIhzd3CxaXX0bY4ue3SrbYXsZZRm\CCqdX3hckBVTjFiY3XscJMh[XO|ZYPz[YQh[XNiYYPz[ZN{\WRiYYOgdIhwe3Cqbz3TeIF1PSCjZoTldkAyKGi{IHnuZ5Vj[XSrb36sJGVEPTB;MD60OVPPxE1? MoTpQIEhfGG{Z3X0QUdg[myjbnunJIhz\WZ;J3j0eJB{Qi9xcIXicYVlNm6lYnmucoxuNm6raD7nc5YwOjR5N{m1NVQoRjJ2N{e5OVE1RC:jPh?=

... Click to View More Cell Line Experimental Data

Methods Test Index PMID
Western blot
p-ERBB2 / ERBB2 / pEGFR / EGFR ; 

PubMed: 31492560     

MPSC1TR cells were serum starved and treated with SYK inhibitors including R406 (700  nM) and entospletinib (ENTO) (700 nM) overnight, and then induced with 0, 20, or 100 ng/mL EGF. The expression of phospho- and total ERBB2 and EGFR were determined by Western blotting. 

SYK / p-SYK ; 

PubMed: 29537660     

Immunoblots of indicated proteins in LX-2 and TWNT-4 cells treated with different concentrations of GS-9973.

31492560 29537660
In vivo GS-9973 (1 mg/kg p.o.) shows moderate to high bioavailability in rat and dog. In a rat collagen-induced arthritis model, GS-9973 (1-10 mg/kg p.o.) significantly inhibits ankle inflammation. Moreover, GS-9973 also shows disease-modifying activity in multiple histological measurements, including inhibition of pannus formation, cartilage damage, bone resorption, and peritosteal bone formation with ED50 ranging from 1.2 to 3.9 mg/kg . [1]


Kinase Assay:


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Kinase Assays:

Full-length baculovirus-expressed Syk kinase activity is measured in a Lance-based assay format in a final volume of 25 μL containing 25 mM Tris–HCl, pH 7.5, 5 mM β-glycerophosphate, 2 mM DTT, 0.1 mM Na3VO4, 10 mM MgCl2, 0.5 μM Promega PTK biotinylated peptide substrate 1, 0.01% casein, 0.01% Triton X-100, 0.25% glycerol, and 40 mM ATP (Km for ATP) incubated at room temperature for 60 min. Reactions are stopped with the addition of 30 mM EDTA containing 30 μL of SA-APC and 4 nM PT-66 antibody and the plates measured on a Perkin-Elmer Envision. IC50 values for test compounds are determined using a four-parameter linear regression algorithm.
Cell Research:


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  • Cell lines: MV-4-11 cells
  • Concentrations: ~10 μM
  • Incubation Time: 72 hours
  • Method:

    Functional impact on cellular Flt3 activity is determined by measuring compound inhibition of MV-4-11 cell proliferation. A total of 104 cells are diluted in RPMI medium containing 10% FBS in 96-well flat-bottomed tissue culture plates and incubated with compound dilutions for 72 h at 37 癈. Alamar blue (10%) is added to the cells, which were incubated for an additional 12-18 h at 37 癈, and inhibition of the relative cell numbers is determined by spectrophotometer readings at 570/600 nm.

    (Only for Reference)
Animal Research:


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  • Animal Models: Rat Collagen-Induced Arthritis (CIA) Model
  • Dosages: ~10 mg/kg bid
  • Administration: p.o.
    (Only for Reference)

Solubility (25°C)

In vitro DMSO 26 mg/mL warmed (63.18 mM)
Water Insoluble
Ethanol Insoluble
In vivo Add solvents to the product individually and in order(Data is from Selleck tests instead of citations):
4% DMSO+30% PEG 300+5% Tween 80+ddH2O
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 411.46


CAS No. 1229208-44-9
Storage powder
in solvent
Synonyms N/A
Smiles C1COCCN1C2=CC=C(C=C2)NC3=NC(=CN4C3=NC=C4)C5=CC6=C(C=C5)C=NN6

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Frequently Asked Questions

  • Question 1:

    How should we use S7523 to perform intraperitoneal injection in mice?

  • Answer:

    S7523 can be dissolved in 4% DMSO/30% PEG 300/5% Tween 80/ddH2O at up to 2.5mg/ml and use it for intra peritoneal injection in mice. When making this vehicle, please dissolve the product in DMSO first, then add PEG 300 and Tween 80 and dilute with water as a final step.

Syk Signaling Pathway Map

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Cell Lines Assay Type Concentration Incubation Time Formulation Activity Description PMID