PD318088

PD318088 is an allosteric and non-ATP competitive MEK1/2 inhibitor.

PD318088 is an analog of PD184352, which means it might have important anti-proliferative activity against cancer cells, although no functional study of PD318088 is currently available. PD318088 binds simultaneously with ATP in a region of the MEK1 active site that is adjacent to the ATP-binding site. Formation of the ternary complexes with PD318088 and MgATP results in moderate increases (to 140 nM) for the Kd monomer-dimer for both MEK1 and MEK2. PD318088 and MgATP together increase the dimerization disassociation constant for MEK1 and MEK2 slightly from ~75 nM to ~140 nM [1].

PD318088 is a biarylamine compound co-crystallized with MEK. G8935 occupies the unique pocket adjacent to ATP binding site and is uperimposed with PD318088 .PD318088 averts to use the pocket formed by Ile216, Phe209, Arg189, and Asp190. [2]

References:
1. Ohren JF1, Chen H, Pavlovsky A et al.  Structures of human MAP kinase kinase 1 (MEK1) and MEK2 describe novel noncompetitive kinase inhibition. Nat Struct Mol Biol. 2004 Dec;11(12):1192-7. Epub 2004 Nov 14.
2. Han S, Zhou V, Pan S et al.  Identification of coumarin derivatives as a novel class of allosteric MEK1 inhibitors. Bioorg Med Chem Lett. 2005 Dec 15;15(24):5467-73. Epub 2005 Sep 30.

Identification of coumarin derivatives as a novel class of allosteric MEK1 inhibitors.[Pubmed:16199156]

Bioorg Med Chem Lett. 2005 Dec 15;15(24):5467-73.

A homogenous TR-FRET-based in vitro coupling assay for the MAP3Ks-MEK1-ERK2 kinase cascade was established and was used to screen for inhibitors of the ERK/MAPK pathway. A series of coumarin derivatives were identified from the screen. These compounds potently inhibit the activation of the unactivated human MEK1 by upstream MAP3Ks (including BRAF and COT), but do not inhibit the activity of the activated MEK1. In addition, the potency of these compounds in inhibiting MEK1 activation is not affected by varying the ATP concentration, suggesting that these inhibitors are not competitive with ATP. As expected, the coumarin compounds potently inhibit LPS-induced TNFalpha production and ERK phosphorylation in THP-1 cells, with the most potent compound having an IC(50) of 90nM. Molecular modeling studies suggest that these coumarins bind to an allosteric site in the inactive conformation of MEK1. This site has been shown to be utilized by the biarylamine series of MEK inhibitors such as PD318088. Very interestingly, the identified coumarin derivatives are almost identical to a series of inhibitors recently reported that block LPS-induced TNFalpha production. Our findings have therefore raised the possibility that other naturally occurring or synthetic coumarins with anti-cancer and anti-inflammatory activities might exert their biological function through the inhibition of MEK1.

Screening of kinase inhibitors targeting BRAF for regulating autophagy based on kinase pathways.[Pubmed:24213221]

Mol Med Rep. 2014 Jan;9(1):83-90.

The aim of this study was to identify agents that regulate autophagy. A total of 544 differentially expressed genes were screened from the intersection set of GSE2435 and GSE31040, which was obtained from the Gene Expression Omnibus database and 19 differentially expressed kinases were selected according to a 'protein kinase database'. Gene ontologybiological process (GO-BP) enrichment analysis revealed that the 19 kinases were mainly associated with phosphorylation. The protein-protein interaction network exhibited 30 differentially expressed genes that interacted with BRAF, and GO-BP enrichment analysis showed the function of these genes were mainly involved in cell death and apoptosis. The kinase-kinase inhibitor regulatory network identified16 kinase inhibitors that specifically inhibited BRAF. Previous studies indicated that sorafenib is capable of regulating autophagy and regorafenib has also been reported; however, there have been no studies regarding the regulation of autophagy by afatinib, selumetinib, PD318088, axitinib, TAK-733, GDC-0980, GSK2126458, PLX-4720, AS703026, trametinib, GDC-0941 and PF-04217903. Thus, these kinase inhibitors are potential targets for further study on the regulation of autophagy in the future.