We reported the discovery of the first covalent inhibitor (WZ-4002) that is selective for the recalcitrant T790M resistance mutant of the epidermal growth factor receptor tyrosine kinase (EGFR), a key target for the treatment of non-small cell lung cancer (NSCLC). This study provided the first example of a ‘mutant-selective’ kinase inhibitor which has quickly become a popular approach to address a number of other oncogenic kinase targets. Inhibitors derived from WZ-4002 are approaching a phase I study at Mass General in Boston.
We reported the discovery and structural characterization of GNF-5, the first allosteric inhibitor of Bcr-Abl kinase that targets a unique c-terminal myristate binding pocket. We demonstrated that GNF-5 induces a conformational rearrangement to the kinase that stabilizes the auto-inhibited conformation. GNF-5 is capable of acting additively with ATP-competitive inhibitors of Bcr-Abl to overcome mutations that render resistance to first generation Bcr-Abl inhibitors. These discoveries have spurred the pharmaceutical development of compounds targeting this unique binding site in Bcr-abl. In addition, the allosteric inhibition strategy provides a useful approach for overcoming mutations that lead to resistance to ATP-competitive inhibitors.
We reported the discovery of Torin1, the first ATP-competitive inhibitor of the mammalian target of rapamycin (mTor). Unlike Rapamycin which only partially inhibits the TORC1 complex, Torin1 can inhibit both TORC1 and TORC2. We demonstrated that there are number of outputs of TORC1 that are more fully inhibited by Torin1 relative to rapamycin. This is a significant finding for the mTor field because most of the effectors downstream of mTor have been defined previously using rapamycin as a pharmacological tool. Torin1 has rapidly become an established reagent for inhibiting mTor and haven been provided to approximately 250 laboratories since its publication in 2009.
We reported the discovery of FIIN-1, the first covalent inhibitor of the fibroblast growth factor receptor tyrosine kinases (FGFRs). We used the inhibitors to identify a number of cancer cell lines that are addicted to FGFR-kinase activity. We outlined a rational design approach that is generally applicable to targeting the large number of kinases that contain reactive cysteine residues in and around their ATP-binding pockets. Several pharmaceutical companies are currently moving FGFR inhibitors into clinical evaluation.
We described chemical strategies that that enable the rational design of inhibitors that could bind to the so-called ‘DFG-out’ conformation of kinases to create ‘type II’ inhibitors (a name we coined). This methodology has now been used to develop type II inhibitors of a large number of kinases.
We described the discovery of TAE684, the first potent inhibitor of NPM-ALK an oncogenic fusion protein that is a driver for Anaplastic Lymphoma, a poorly treated pediatric tumor. Subsequently, this inhibitor was used to identify a new fusion kinase EML4-ALK as a prime oncogenic target for the treatment of a subset of non-small cell lung cancer (NSCLC). A number of inhibitors derived from TAE684 are currently in clinical trials for the treatment of EML4-ALK positive NSCLC. TAE684 was also used to identify oncogenic point mutations in ALK which has stimulated clinical application of ALK inhibitors for the treatment of a subset of Neuroblastoma.
We describe the discovery of the first Mps1-IN-1, the first potent and selective ATP-competitive inhibitor of the mitotic spindle checkpoint kinase Mps1. We used the inhibitor to demonstrate that Mps1 kinase activity is a key regulator of the duration of mitosis and that inhibition of Mps1 leads to massive chromosome segregation errors. We demonstrated that while Mps1 leads to loss of viability of a variety of cancer cell lines, it exhibits a very small window of selectivity relative to non-cancer cell lines. Mps1-IN-1 is currently commercially available and has become a popular pharmacological tool.
We describe the discovery of XMD8-92 the first potent and selective inhibitor of BMK1 (also known as Erk5). BMK1 is the ‘terminal’ kinase in a fourth branch of the MAPK pathway and is considerably less investigated relative to Erk1,2, p38 and JNK. We used XMD8-92 to demonstrate that BMK1 inhibition results in stabilization of p53 and loss of viability of a variety of tumors. XMD8-92 has become a popular pharmacological probe of BMK1-dependent biology.
We describe the discovery of LRRK2-IN-1 the first potent and selective inhibitor of LRRK2, a poorly understood kinase that becomes mutated in a subset of patients with early onset Parkinson’s disease. We have used LRRK2-IN-1 to demonstrate that inhibition of LRRK2 kinase activity results in a dramatic relocalization of the kinase from the cytoplasm to dense concentrates located proximal to the cell nucleus. We identified mutations in LRRK2 which could confer resistance to the inhibitor which provides a powerful means to address the LRRK2 –specificity of observed pharmacology. LRRK2-IN-1 is now commercially available and widely used by the research community to investigate LRRK2-dependent cell biology such as identifying new substrates and transcriptional output downstream of the kinase.
We developed a potent ‘type II’ ATP-competitive compound capable of inhibiting the recalcitrant T315I gatekeeper mutant of Bcr-Abl. This compound was also capable of inhibiting the corresponding gatekeeper mutant in PDGFR and c-kit, two other important therapeutic kinase targets. Structural studies in complex with Src showed how the compound could ‘snake’ its way around a large gatekeeper amino acid. The demonstration of the ‘type II’ strategy for overcoming gatekeeper resistance mutations has been adopted by two compounds currently in phase I clinical investigation for the treatment of gleevec-resistant T315I Bcr-Abl expressing Chronic Myelogenous Leukemia.