Inhibition of cIAP1 as a strategy for targeting c-MYC-driven oncogenic activity.
Proc Natl Acad Sci U S A
; 115(40): E9317-E9324, 2018 10 02.
Article
in En
| MEDLINE
| ID: mdl-30181285
ABSTRACT
Protooncogene c-MYC, a master transcription factor, is a major driver of human tumorigenesis. Development of pharmacological agents for inhibiting c-MYC as an anticancer therapy has been a longstanding but elusive goal in the cancer field. E3 ubiquitin ligase cIAP1 has been shown to mediate the activation of c-MYC by destabilizing MAD1, a key antagonist of c-MYC. Here we developed a high-throughput assay for cIAP1 ubiquitination and identified D19, a small-molecule inhibitor of E3 ligase activity of cIAP1. We show that D19 binds to the RING domain of cIAP1 and inhibits the E3 ligase activity of cIAP1 by interfering with the dynamics of its interaction with E2. Blocking cIAP1 with D19 antagonizes c-MYC by stabilizing MAD1 protein in cells. Furthermore, we show that D19 and an improved analog (D19-14) promote c-MYC degradation and inhibit the oncogenic function of c-MYC in cells and xenograft animal models. In contrast, we show that activating E3 ubiquitin ligase activity of cIAP1 by Smac mimetics destabilizes MAD1, the antagonist of MYC, and increases the protein levels of c-MYC. Our study provides an interesting example using chemical biological approaches for determining distinct biological consequences from inhibiting vs. activating an E3 ubiquitin ligase and suggests a potential broad therapeutic strategy for targeting c-MYC in cancer treatment by pharmacologically modulating cIAP1 E3 ligase activity.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Proto-Oncogene Proteins c-myc
/
Drug Delivery Systems
/
Inhibitor of Apoptosis Proteins
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Ubiquitination
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Neoplasms
/
Antineoplastic Agents
Type of study:
Prognostic_studies
Limits:
Animals
/
Humans
Language:
En
Journal:
Proc Natl Acad Sci U S A
Year:
2018
Type:
Article
Affiliation country:
China