Investigating allosteric regulation of ABL and BCR-ABL kinases: Implications for small molecule inhibitors

摘要: BCR-ABL is the oncogenic protein-tyrosine kinase responsible for pathogenesis of chronic myelogenous leukemia (CML). Clinical management CML has been revolutionized by imatinib, a selective ATP-competitive inhibitor activity. Despite this clinical success, imatinib less effective in advanced disease due to emergence drug resistant mutants. Resistant mutations often arise binding site and include most recalcitrant gatekeeper mutation, T315I. Other outside active allosterically reduce promoting conformation. Recently, new class allosteric inhibitors, which GNF-2 prototype, reported that targets myristate-binding pocket ABL. These compounds stabilize inactive conformation ABL work concert with inhibitors overcome resistance. Mounting evidence supports regulatory influence non-catalytic SH3 SH2 domains on domain. The major focus study was exploit intramolecular SH3:linker interaction, downregulated domain sensitize both GNF-2. To achieve goal, I engineered High Affinity Linker (HAL) variants interaction tightened through sequential addition proline residues linker. Enhanced induced long-range suppressive effects activity c-ABL, stabilized pocket, sensitized small molecule inhibitors. Src family kinases (SFKs) are important mediators signal transduction oncogenesis CML. SFKs also play roles resistance absence mutations. In second part my project, explored effect SFK- inhibitor, pyrazolopyrimidine A-419259, myeloid cells transformed clinically relevant While proliferation expressing E255V Y253H inhibited T315I were not. Surprisingly, BCR-ABL-T315I maintained SFK presence inhibitor. This observation suggests induces cross-resistance drugs inhibit direct phosphorylation SFKs.