Investigation of Methods for the Generation of Selective Small-molecule Kinase Inhibitors.

[摘要] Protein kinases have evolved as key players in the signaling processes that allow the mammalian cell to respond to environmental stimuli. Determination of the function of each the individual members of this large class of enzymes is aided by development of selective inhibitors. Most kinase inhibitors function through binding the highly conserved ATP-pocket and are often poorly selective as a result. This dissertation assesses two general strategies to improve kinase inhibitor selectivity. One strategy regards ATP-competitive inhibitors which target distinct kinase folds, and an orthogonal strategy regards targeting inhibitor binding sites outside of the highly conserved ATP-pocket.First, the drug dasatinib is rationally altered to provide two sets of inhibitors which respectively bind distinct ;;inactive” kinase folds (DFG-out and c-helix out). Large scale selectivity profiling reveals that most of dasatinib’s kinase targets can adopt the DFG-out conformation, while the c-helix out conformation appears less conserved. These results imply that targeting inactive conformations does not necessarily entail higher kinase inhibitor selectivity. Second, inhibitors that target regions outside of the ATP-pocket are developed using a bivalent approach. A fragment intended to target a region outside of the ATP-pocket is covalently tethered to an ATP-competitive inhibitor. Application of this strategy demonstrates the amount of selectivity that can be gained from targeting alternate pockets. In one example, we show that the site at which kinases bind their protein target can be modularly targeted for highly selective inhibition. In another example, the development of a highly selective c-Src inhibitor is achieved through targeting the phosphate binding-loop region. In an application of our c-Src selective inhibitor, it is shown that selective inhibition is more effective than multi-kinase inhibition in the treatment of several cancer cell lines.Altogether this dissertation provides insight regarding the design of selective kinase inhibitors. One study reveals that ATP-competitive inhibitors that bind ;;inactive” kinase folds appear to be much less selective than previously suggested. A second study demonstrates that targeting sites outside of the ATP-pocket can provide very highly selective kinase inhibitors.

[发布机构] University of Michigan

[效力级别] Chemistry

[关键词] Selective Kinase Inhibitors;Chemistry;Science;Medicinal Chemistry