9 research outputs found
Establishing Drug Discovery and Identification of Hit Series for the Anti-apoptotic Proteins, Bcl-2 and Mcl-1
We describe our work to establish structure- and fragment-based drug discovery to identify small molecules that inhibit the anti-apoptotic activity of the proteins Mcl-1 and Bcl-2. This identified hit series of compounds, some of which were subsequently optimized to clinical candidates in trials for treating various cancers. Many protein constructs were designed to identify protein with suitable properties for different biophysical assays and structural methods. Fragment screening using ligand-observed NMR experiments identified several series of compounds for each protein. The series were assessed for their potential for subsequent optimization using 1H and 15N heteronuclear single-quantum correlation NMR, surface plasmon resonance, and isothermal titration calorimetry measurements to characterize and validate binding. Crystal structures could not be determined for the early hits, so NMR methods were developed to provide models of compound binding to guide compound optimization. For Mcl-1, a benzodioxane/benzoxazine series was optimized to a Kd of 40 μM before a thienopyrimidine hit series was identified which subsequently led to the lead series from which the clinical candidate S 64315 (MIK 665) was identified. For Bcl-2, the fragment-derived series were difficult to progress, and a compound derived from a published tetrahydroquinone compound was taken forward as the hit from which the clinical candidate (S 55746) was obtained. For both the proteins, the work to establish a portfolio of assays gave confidence for identification of compounds suitable for optimization
Design of Leucine-Rich Repeat Kinase 2 (LRRK2) Inhibitors Using a Crystallographic Surrogate Derived from Checkpoint Kinase 1 (CHK1)
Mutations in leucine-rich repeat
kinase 2 (LRRK2), such as G2019S,
are associated with an increased risk of developing Parkinson’s
disease. Surrogates for the LRRK2 kinase domain based on checkpoint
kinase 1 (CHK1) mutants were designed, expressed in insect cells infected
with baculovirus, purified, and crystallized. X-ray structures of
the surrogates complexed with known LRRK2 inhibitors rationalized
compound potency and selectivity. The CHK1 10-point mutant was preferred,
following assessment of surrogate binding affinity with LRRK2 inhibitors.
Fragment hit-derived arylpyrrolo[2,3-<i>b</i>]pyridine
LRRK2 inhibitors underwent structure-guided optimization using this
crystallographic surrogate. LRRK2-pSer935 HEK293 IC<sub>50</sub> data
for <b>22</b> were consistent with binding to Ala2016 in LRRK2
(equivalent to Ala147 in CHK1 10-point mutant structure). Compound <b>22</b> was shown to be potent, moderately selective, orally available,
and brain-penetrant in wild-type mice, and confirmation of target
engagement was demonstrated, with LRRK2-pSer935 IC<sub>50</sub> values
for <b>22</b> in mouse brain and kidney being 1.3 and 5 nM,
respectively
X-Ray, Quantum Mechanics and Density Functional Methods in the Examination of Structure and Tautomerism of N-Methyl-Substituted Acridin-9-amine Derivatives
Conformational analysis of the first observed non-proline cis-peptide bond occurring within the complementarity determining region (CDR) of an antibody
Novel Adenosine-Derived Inhibitors of 70 kDa Heat Shock Protein, Discovered Through Structure-Based Design
The design and synthesis of novel adenosine-derived inhibitors of HSP70, guided by modeling and X-ray crystallographic structures of these compounds in complex with HSC70/BAG-1, is described. Examples exhibited submicromolar affinity for HSP70, were highly selective over HSP90, and some displayed potency against HCT116 cells. Exposure of compound 12 to HCT116 cells caused significant reduction in cellular levels of Raf-1 and Her2 at concentrations similar to that which caused cell growth arrest
Adenosine-Derived Inhibitors of 78 kDa Glucose Regulated Protein (Grp78) ATPase: Insights into Isoform Selectivity
The MCL1 inhibitor S63845 is tolerable and effective in diverse cancer models
Avoidance of apoptosis is critical for the development and sustained growth of tumours. The pro-survival protein myeloid cell leukemia 1 (MCL1) is overexpressed in many cancers, but the development of small molecules targeting this protein that are amenable for clinical testing has been challenging. Here we describe S63845, a small molecule that specifically binds with high affinity to the BH3-binding groove of MCL1. Our mechanistic studies demonstrate that S63845 potently kills MCL1-dependent cancer cells, including multiple myeloma, leukaemia and lymphoma cells, by activating the BAX/BAK-dependent mitochondrial apoptotic pathway. In vivo, S63845 shows potent anti-tumour activity with an acceptable safety margin as a single agent in several cancers. Moreover, MCL1 inhibition, either alone or in combination with other anti-cancer drugs, proved effective against several solid cancer-derived cell lines. These results point towards MCL1 as a target for the treatment of a wide range of tumours