Development of peptidomimetic inhibitors of the ERG transcription factor in prostate cancer (ChIP-seq)

Transcription factors play a key role in the development of a number of cancers, and therapeutically targeting them has remained a challenge. In prostate cancer, the ETS transcription factor ERG is recurrently rearranged and likely plays a critical role in prostate oncogenesis. Here we identified a series of peptides from a phage-display library that interact specifically with the DNA binding domain of ERG. The interactive interface was mapped to 9-residues in the 3rd helix of the ETS domain that is critical for ERG transcriptional activity. The peptides were found to efficiently disrupt ERG-mediated protein-protein interactions, transcription, DNA damage, and cell invasion, as well as attenuate ERG recruitment to target gene loci. Furthermore, a retroinverso peptidomimetic version of the peptide sequence suppressed tumor growth, intravasation, and metastasis in vivo. Taken together, our results demonstrate that transcription factors have specific residues important for protein-protein interactions and disrupting those critical interactions may be an effective therapeutic strategy. Overall design: Examination of ERG in VCaP cells with respect to peptidomimetics treatment