Design And Syntheses Of Phenylpyrimidine Derivatives As Potential Allosteric Kinase Inhibitors And Anticancer Activity

Protein kinases which can catalyze protein phosphorylation play pivotal roles inregulating almost all aspects of cellular functions including proliferation and apoptosis. Inthe field of oncology, the dysregulations of kinases have been implicated in a number ofdisease areas ranging from neuronal disorders to oncology. For these reasons, protein kinaseshave become one of the most comprehensive classes of therapeutic targets, and proteinkinase inhibitors which have the promise of low toxicity, high efficiency and specificity arealso becoming potential anticancer drugs.This thesis consists of two chapters, and focused on the design and syntheses ofphenylpyrimidine derivatives as potential allosteric kinase inhibitors and their anticanceractivity. The first chapter summarized the current status of kinase inhibitors, providedexamples of kinase inhibitors and their classification according to their mechanism of action.On the basis of these arguments we introduce the purpose and significance of ourexperiments.During the past two decades, more than ten kinase inhibitors have been successfullymarketed and proven to be effective therapies for various forms of cancer, and numeroussmall molecules targeting kinases are in various development stages, and being continuouslyadvanced into the clinics. Most of the small molecules kinase inhibitors reported so far canbe classified into two main categories, Type I and Type II kinase inhibitors, based on theirmode of action. Type I inhibitors bind to the ATP site of the kinase’s active conformation.They modulate the kinase activity by directly compete with ATP for the same binding site.For this reason, they are also termed as “ATP-competitive inhibitors”. The sequence ofamino acids in the ATP binding sites are highly conserved among kinases and other ATPbinding proteins. As a result, Type I inhibitors typically have poor selectivity profile. Type IIinhibitors are also known as allosteric inhibitors, occupy the region which vacated by therotation of the activation-loop and adenine region of the adenosine triphosphate ATP. Allosteric kinase inhibitors have been shown to possess the advantages of high selectivityand high activity which lead to better clinical safety and efficacy.The second chapter describes the design and syntheses of phenylpyrimidine derivativesas potential allosteric kinase inhibitors and evaluation of their anticancer activity. Byanalyzing allosteric conformation of kineses and their inhibitors, as well as their X-ray co-crystal structures, we proposed a pharmacophore model with bi-cyclic phenylpyrimidine.The template serves as a connect, bridging the original adenine binding region and thehydrophobic cavity vacated by the DFG-fragment. We synthesized pharmacophorephenylpyrimidine core (2-2) via one-pot Suzuki coupling in high yield, and comfirmed itsstructer by X-ray crystallography. Derivation of the core provided as with a drug-like smallmolecular library of57compounds. This library was screened in cell assays against HeLacells for their anti-proliferative activities. Lead compounds with good activity wereidentified. Their activities were further improved by structure-activity relationshipdevelopment. Lead compound2-12q was also studied in a kinome screen against217kinases and showed good inhibitory activity against serveal kinases, that can assume theDFG-out conformation.The work in this thesis indicates that pharmacophore approach can be an effective routefor the identification of novel allosteric kinases inhibitors. The phenylpyrimidine template isa suitable fragment for inducing DFG-out conformation. Further derivation of this templatecould lead to potential selective allosteric kinase inhibitors.