Skepinone-L

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Chemical Probes Portal Skepinone-L.pdf

Protein target name:

MAPK14

Mechanism of action:

ATP-competitive inhibitor

Recommended Concentration for use in cells:

100-400 nM

Probe Availability

MedChem Express (1221485-83-1)

Probe Information

Target and Probe Information

Target Details

Target class:

Protein kinase

Subclass:

CMGC

HUGO ID:

HGNC:6876

Entrez gene ID:

1432

UNIPROT ID:

Q16539

Target alias:

CSBP, CSBP1, CSBP2, CSPB1, EXIP, Mxi2, PRKM14, PRKM15, RK, SAPK2A, p38, p38ALPHA, p38 MAPK alpha

Probe Details

Chemical Probes Portal ID:

CPP1426

PubChem CID:

45279963

ChEMBL ID:

CHEMBL2152944

SMILES string:

C1CC2=C(C=CC(=C2)NC3=C(C=C(C=C3)F)F)C(=O)C4=C1C=CC(=C4)OC[C@@H](CO)O

InChi Key:

HXMGCTFLLWPVFM-GOSISDBHSA-N

Orthogonal probe:

VX-745FS-694SR-318

Validation in Cells and Model Organisms

In vitro validation

On target activity

Potency:

1.5 nM

Potency assay:

Ambit Biosciences binding assay. In enzyme activity assays, IC50= 5 nM.

PDB ID for probe-target interaction (3D structure):

3ZYA, 3QUE

Structure-activity relationship:

Yes, see J Med Chem paper

Off target activity

Potency assay (off target):

In a panel of 402 kinases at 1 uM, no notable activity was detected other than for p38 MAPK alpha and beta. Comparable results were obtained in ProQinase GmbH panel of 333 kinases.

In cell validation

On target activity in cells

Potency in cells:

IC50

40 nM

Potency assay (cells):

In whole blood assay. In HeLa cells, IC50=25 nM for inhibition of HSP27 phosphorylation.

Target engagement assay (cells):

Indirect, inhibition of substrate phosphorylation

Off target activity in cells

Potency assay, off target (cells):

Skepinone-L did not affect phosphorylation of c-Jun or CREB.

In vivo validation

Organism:

Mouse

Route of delivery:

Oral

Cmax:

240 nM

Primary Reference

Reference (doi):

10.1038/nchembio.761 10.1021/jm300327h

Reference (PMID):

22198732 22676210

Endorsed probe

The Chemical Probes Portal endorses this compound as chemical probe for use in cells and in model organisms.

SAB Rating

Rating for use in Cells

3 review(s)

Rating for use in Model Organisms

3 review(s)

SAB Members

SAB Comments

Skepinone-L is a potent, selective, and cell active p38 inhibitor. It is orally bioavailable in mice. It shows exquisite kinase selectivity, as measured by screening against broad panels at Ambit (DiscoveRx) and ProQinase. Part of this selectivity arises from the design of the molecule to take advantage of the so-called "glycine flip", which can only occur in a small subset of kinases.

Mar 18 2017 - 8:33pm

Experiments for selectivity in cells included an Ambit screen and a ProQuinase panel. Structure-activity relationships are logical and structurally based. I would like to see evidence for and against off-targets beyond kinases, but otherwise this is a potent, orally bioavailable probe with very good selectivity. A careful metabolism study was reported in DOI: 10.1039/C4MD00106K.

Apr 3 2017 - 12:48pm

Skepinone-L is a potent (5 nM) p38alpha/beta-dual inhibitor with wonderful kinome selectivity (minimal to no activity on 300+ kinases at 1 uM). It has activity in a cell-based, mechanistic assay at 25 nM and relevant phenotypic assay at 30-50 nM, and showed reduction of a relevant biomarker when dosed orally in mice at 3 mg/kg. A smooth sigmoidal dose response in the mechanistic assay suggests no cytotoxicity at the high dose of 10 uM, though its unclear of HSP27 phosphorylation in the time frame of the assay is a good indicator of cytotoxicity. Dose response was not reported for phenotypic endpoints. In vitro metabolism reported elsewhere suggests comparable PK in rat and some gender differences in both species, but these findings have not been confirmed in vivo. This appears to be a good tool for research, with the caveat that there may be better characterized tools for chronic, in vivo dosing available among the many clinical assets that have been disclosed, including SCIO-469/talmapimod (even more selective), VX-702, VX-745, losmapimod, dilmapimod, pamapimod, etc. For most of those molecules, more chronic, disease-relevant endpoints have been reported, and by virtue of their administration to humans, we can implicitly assume they have a relatively clean tox history in rodents at doses above the therapeutic dose (if not explicitly reported). If selectivity over p38beta is required for in vitro experiments, SX-011 appears to be the most selective tool available (~250X selective for p38alpha over beta).

Jun 5 2017 - 1:01pm

Skepinone-L

Probe Availability

Probe Information

Target Details

CSBP, CSBP1, CSBP2, CSPB1, EXIP, Mxi2, PRKM14, PRKM15, RK, SAPK2A, p38, p38ALPHA, p38 MAPK alpha

Probe Details

In vitro validation

In cell validation

In vivo validation

Primary Reference

Supporting Organizations

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Skepinone-L

Probe Availability

Probe Information

Target Details

CSBP, CSBP1, CSBP2, CSPB1, EXIP, Mxi2, PRKM14, PRKM15, RK, SAPK2A, p38, p38ALPHA, p38 MAPK alpha

Probe Details

In vitro validation

In cell validation

In vivo validation

Primary Reference

Supporting Organizations

Interested in supporting the portal?