Proteomic profiling identifies key coactivators utilized by mutant ER? proteins as potential new therapeutic targets.

ABSTRACT: Approximately 75% of breast cancers are estrogen receptor alpha (ER?)-positive and are treatable with endocrine therapies, but often patients develop lethal resistant disease. Frequent mutations (10-40%) in the ligand-binding domain (LBD) codons in the gene encoding ER? (ESR1) have been identified, resulting in ligand-independent, constitutively active receptors. In addition, ESR1 chromosomal translocations can occur, resulting in fusion proteins that lack the LBD and are entirely unresponsive to all endocrine treatments. Thus, identifying coactivators that bind to these mutant ER? proteins may offer new therapeutic targets for endocrine-resistant cancer. To define coactivator candidate targets, a proteomics approach was performed profiling proteins recruited to the two most common ER? LBD mutants, Y537S and D538G, and an ESR1-YAP1 fusion protein. These mutants displayed enhanced coactivator interactions as compared to unliganded wild-type ER?. Inhibition of these coactivators decreased the ability of ESR1 mutants to activate transcription and promote breast cancer growth in vitro and in vivo. Thus, we have identified specific coactivators that may be useful as targets for endocrine-resistant breast cancers.

SUBMITTER: Gates LA 

PROVIDER: S-EPMC6095836 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature