The ubiquitin-proteasome system (UPS), which controls the degradation of proteins inside the cell, plays an integral role in maintaining cellula protein homeostasis. Dysregulation of the UPS is associated with a growing number of diseases including cancers, neurodegenerative disorders, and viral and bacterial infections. As a result, regulators of the UPS have received considerable attention for developing new human therapeutics. The current FDA approved therapeutics, which target the UPS, are efficacious but also fairly toxic - probably because they completely shut down the activity of the UPS. This proposal seeks to address this problem by developing small molecule inhibitors of DCN1 that regulate the UPS without completely blocking its activity. DCN1 is a recently identified protein whose dysregulation is associated with a number of human cancers. DCN1 activity is controlled by its interaction with UBC12. Therefore, the goal of this proposal is to develop potent and selective small molecule inhibitors that disrupt the DCN1-UBC12 protein-protein interaction and use them to elucidate the biological effects of DCN1 mediated UPS regulation.
Aim 1 addresses the optimization of DCN1-UBC12 interaction inhibitors, identified by a high-throughput screening campaign, based on biochemical potency and models for cellular and organismal bioavailability.
Aim 2 addresses whether or not chemical disruption of the DCN1-UBC12 interaction functionally and selectively inhibits neddylation, cullin-RING E3 ligase activity, UPS activity, and effectively suppresses tumor growth in clinically relevant in vivo models. If the DCN1-UBC12 interaction is validated as a target for regulation of the UPS, this new mechanism of action will provide a useful tool for elucidating the molecular mechanisms of DCN1 mediated CRL activity and regulation of the UPS. These studies will increase our understanding of a key life process and potentially lay the foundation for significant advances in the development of highly selective therapeutics.

Public Health Relevance

Dysregulation of the ubiquitin-proteasome system (UPS), which controls the degradation of proteins inside the cell, is associated with a growing number of diseases including cancers, neurodegenerative disorders, and viral and bacterial infections. The goal of this proposal is to develop potent and selective small molecule inhibitors of DCN1 activity that regulate the UPS without completely shutting it down. The proposed studies will provide a useful tool for understanding a key life process and may also lay the foundation for the development of novel therapeutics for the treatment of cancer and other diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
1F32GM113310-01
Application #
8830740
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Barski, Oleg
Project Start
2015-03-01
Project End
2017-02-28
Budget Start
2015-03-01
Budget End
2016-02-29
Support Year
1
Fiscal Year
2015
Total Cost
Indirect Cost
Name
St. Jude Children's Research Hospital
Department
Type
DUNS #
067717892
City
Memphis
State
TN
Country
United States
Zip Code
38105
Scott, Daniel C; Hammill, Jared T; Min, Jaeki et al. (2017) Blocking an N-terminal acetylation-dependent protein interaction inhibits an E3 ligase. Nat Chem Biol 13:850-857