Drug Discovery for First-In-Class Myosin 10 Inhibitors as a Novel Target for Glioblastoma - PROJECT SUMMARY
An area of significant unmet need is the effective treatment of glioblastoma (GBM), an aggressive, fast-growing
brain cancer that represents 48% of all malignant brain tumors. If left untreated, GBM is typically fatal within
three months. Due to a high rate of recurrence, the current standard of care, consisting of safe maximal tumor
resection, radiation therapy and chemotherapy, only extends survival following initial diagnosis to 1 year, with
<5% of patients surviving longer than five years. Invasion and proliferation are defining hallmarks of cancer,
and in GBM, blocking one stimulates the other. This implies that effective therapy requires inhibiting both
simultaneously. We have found that the molecular motor myosin 10 (Myo10) meets these criteria. Myo10
deletion impairs invasion, slows proliferation, and prolongs survival in murine models of GBM. Although tumors
still form, Myo10 deletion also enhances tumor cell dependency on both DNA damage and metabolic stress
responses, inducing synthetic lethality when combined with FDA approved inhibitors of these processes.
Results demonstrate that a therapeutic strategy targeting Myo10 is expected to be tolerated and have an anti-
tumor effect that can also synergize with established therapies. However, pursuing the translational potential of
Myo10 in GBM has been limited by the complete lack of molecular probes for this myosin. Thus, the overall
goal of this proposal is to perform a large scale high throughput screening (HTS) campaign in the R61 phase
using the Scripps Institutional Drug Discovery Library (SDDL) of >665,000 compounds to identify and
subsequently validate, characterize and optimize first-in-class therapeutic agents targeting Myo10 in the R33
phase. Successful transition to the R33 phase will be determined by the Go/No-Go criteria of identifying at
least two chemically distinct structural scaffolds for optimization. Far more are anticipated and plans are in
place to prioritize hits. The inter-disciplinary team of investigators combines uniquely complementary expertise
in GBM, myosin biology, HTS screening, medicinal chemistry, drug development and the clinical treatment of
GBM. Preliminary data garnered from a 1.28K compound LOPAC screen demonstrates that the project is
ready for a full-scale HTS campaign, having demonstrated the primary assay is HTS compatible with an
excellent Z’, high assay reproducibility and a lack of false positives. Readiness is further supported by a
counterscreen in place that utilizes the same approach as the primary screen, titration assays and a
comprehensive screening funnel to support the medicinal chemistry. A primary lead and a back-up resulting
from these efforts will then be advanced under a different funding mechanism for development as a GBM
treatment (e.g. IGNITE in vivo efficacy PAR-18-761 and BPN Small Molecule Drug Discovery and
Development PAR-20-122). Further, we anticipate that the resulting small molecule inhibitors of Myo10 will
enable discovery of indications in addition to GBM where its modulation would be therapeutically beneficial.
