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Biological Activity
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Description
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PH-797804 is a novel pyridinone inhibitor of p38α with IC50 of 26 nM. |
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Targets
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p38α |
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IC50 |
26 nM [1] |
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In Vitro
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PH-797804 blocks LPS-induced TNF-α production and p38 kinase activity in the human monocytic U937 cell line, with comparable IC50 of 5.9 nM and 1.1 nM. PH-797804 has no inhibitory effect on either the JNK pathway (c-Jun phosphorylation) or ERK pathway (ERK phosphorylation) in U937 cells at concentrations up to 1 μM. PH-797804 inhibits RANKL- and M-CSF-induced osteoclast formation in a concentration-dependent manner, with IC50 of 3 nM in primary rat bone marrow cells. [1] IC50 values for PH-797804 against the following targets have been determined to be greater than 200 μM (unless specified): CDK2, ERK2, IKK1, IKK2, IKKi, MAPKAP2, MAPKAP3, MKK7 (>100 μM), MNK, MSK (>164 μM), PRAK, RSK2, and TBK1, which means the activity of PH-797804 is specific. [2] |
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In Vivo
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Orally dosing of PH-797804 effectively inhibits acute inflammatory responses induced by systemically administered endotoxin in both rat and cynomolgus monkeys. PH-797804 treatment for 10 days demonstrates robust anti-inflammatory activity in chronic disease models, significantly reducing both joint inflammation and associated bone loss in streptococcal cell wall-induced arthritis in rats and mouse collagen-induced arthritis. Dose-response analysis resulted in ED50 values of 0.07 mg/kg and 0.095 mg/kg in rat and cynomolgus monkeys, respectively. PH-797804 inhibits LPS-induced TNF-α, IL-6, and MK-2 activity in a dose- and concentration-dependent manner in a human endotoxin challenge model. [1] |
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Clinical Trials
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PH-797804 is now under the Phase II clinical trial to evaluate the efficacy and safety for 12 weeks in adults with moderate to severe chronic obstructive pulmonary disease (COPD). |
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Features
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Protocol
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Kinase Assay
[1]
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| P38 kinase assay |
A resin capture assay method is used to determine the phosphorylation of epidermal growth factor receptor peptide (EGFRP) or GST-c-Jun by p38 kinases. Reactions mixtures contain 25 mM HEPES, pH 7.5, 10 mM magnesium acetate, ATP (at the indicated concentration), 0.05 to 0.3 μCi of [γ-33P]ATP, 0.8 mM dithiothreitol, and either 200 μM EGFRP or 10 μM GST-c-Jun for p38α kinase reactions. The reaction is initiated by the addition of 25 nM p38α kinase to give a final volume of 50 μl. The p38αkinase reactions are incubated at 25 °C for 30 minutes. Under these conditions, the formation of product for both p38αkinase is linear with time. The reaction is stopped, and the unreacted [γ-33P]ATP is removed by the addition of 150 μl of AG 1 × 8 ion exchange resin in 900 mM sodium formate, pH 3.0. Once thoroughly mixed, solutions are allowed to stand for 5 minutes. A 50-μl aliquot of head volume containing the phosphorylated substrate is removed from the mixture and transferred to a 96-well plate. MicroScint-40 scintillation cocktail (150 μL) is added to each well and the radioactivity quantities using a TopCount NXT microplate scintillation and luminescence counter. |
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Cell Assay
[1]
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| Cell Lines |
Rheumatoid arthritis synovial fibroblast(s) |
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| Incubation Time |
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| Methods |
Cell viability is evaluated using the 3-(4,5-dimethylthiazol-2-yl)-) diphenyl tetrazolium bromide assay. Absorbance is measured on an ELISA plate reader with a test wavelength of 570 nm and a reference of 630 nm. |
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Animal Study
[1]
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| Animal Models |
LPS-induced chronic inflammation rat model |
| Formulation |
PH-797804 is prepared as a suspension in a vehicle consisting of 0.5% methylcellulose and 0.025% Tween 20. |
| Doses |
0.001-1 mg/kg |
| Administration |
Oral gavage 4 hours before LPS administration |
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