Application of Off-Rate Screening in the Identification of Novel Pan-Isoform Inhibitors of Pyruvate Dehydrogenase Kinase

Libraries of nonpurified
resorcinol amide derivatives were screened
by surface plasmon resonance (SPR) to determine the binding dissociation
constant (off-rate, kd) for compounds
binding to the pyruvate dehydrogenase kinase (PDHK) enzyme. Parallel
off-rate measurements against HSP90 and application of structure-based
drug design enabled rapid hit to lead progression in a program to
identify pan-isoform ATP-competitive inhibitors of PDHK. Lead optimization
identified selective sub-100-nM inhibitors of the enzyme which significantly
reduced phosphorylation of the E1α subunit in the PC3 cancer
cell line in vitro.