Project description:Transcription factors play a key role in the development of diverse cancers, and therapeutically targeting them has remained a challenge. In prostate cancer, the gene encoding the transcription factor ERG is recurrently rearranged and plays a critical role in prostate oncogenesis. Here, we identified a series of peptides that interact specifically with the DNA binding domain of ERG. The most prevalent consensus peptide series matched the tumor suppressor Deleted in Liver Cancer 1 (DLC1). ERG inhibitory peptides and derived peptidomimetics (EIPs) bound with high affinity and specificity leading to proteolytic degradation of ERG. The EIPs attenuated ERG-mediated transcription, chromatin recruitment, protein-protein interactions, cell invasion, and tumor growth. Thus, peptidomimetic targeting of transcription factor fusion products may provide a promising therapeutic strategy for prostate cancer as well as other cancers.
Project description: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. Prostate cancer cell line VCaP were treated with 10µM of RI-EIP1 or RI-muEIP1 for 48 hr
Project description:Common epithelial cancers are believed to become more aggressive through the accumulation of multiple independent molecular events that lead to the deregulation of cell signaling. However, the discovery that the majority of prostate cancers harbor gene fusions of the 5'-untranslated region of androgen regulated TMPRSS2 promoter with ETS transcription factor family members has brought this paradigm into question1,2. TMPRSS2-ERG gene fusion is the most common molecular sub-type of prostate cancer. Recent work suggests that the TMPRSS2-ERG fusion is associated with a more aggressive clinical phenotype3. In the most advanced castration resistant prostate cancers where the androgen receptor has been inactivated, the TMPRSS2-ERG fusion remains functionally active. Here we show compelling clinical and gene expression data supporting the existence of a TMPRSS2-ERG fusion prostate cancer subclass. Using expression array profiling on 455 primary prostate tumors, we identified an 87 gene expression signature, distinguishing TMPRSS2-ERG fusion prostate cancer as a discrete molecular entity. Computational analysis suggested that this fusion signature was associated with estrogen receptor signaling. Functional studies demonstrated regulation of the TMPRSS2-ERG fusion transcript by estrogenic compounds. These data identify a previously unrecognized mechanism for regulation of the TMPRSS2-ERG, even in the absence of a functional androgen receptor, and thus may have broader implications in the treatment of prostate cancer. Keywords: Prostate cancer, Expression array, Illumina, gene fusion, TMPRSS2, ERG, Signatures, Estrogen Test Cohort: 388 cases from the population based Swedish-Watchful Waiting cohort. The cohort consists of men with localized prostate cancer (clinical stage T1-T2, Mx, N0); Validation cohort: The PhysiciansM-bM-^@M-^Y Health Study (PHS) cohort included 116 US men diagnosed with incidental prostate cancer between 1983 and 2003; 455 cases were annotated for TMPRSS2-ERG fusion. Test Set: GSM208029 ... GSM208392 Validation Set: GSM208404 ... GSM208512
Project description: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. Examination of ERG in VCaP cells with respect to peptidomimetics treatment
Project description:Common epithelial cancers are believed to become more aggressive through the accumulation of multiple independent molecular events that lead to the deregulation of cell signaling. However, the discovery that the majority of prostate cancers harbor gene fusions of the 5'-untranslated region of androgen regulated TMPRSS2 promoter with ETS transcription factor family members has brought this paradigm into question1,2. TMPRSS2-ERG gene fusion is the most common molecular sub-type of prostate cancer. Recent work suggests that the TMPRSS2-ERG fusion is associated with a more aggressive clinical phenotype3. In the most advanced castration resistant prostate cancers where the androgen receptor has been inactivated, the TMPRSS2-ERG fusion remains functionally active. Here we show compelling clinical and gene expression data supporting the existence of a TMPRSS2-ERG fusion prostate cancer subclass. Using expression array profiling on 455 primary prostate tumors, we identified an 87 gene expression signature, distinguishing TMPRSS2-ERG fusion prostate cancer as a discrete molecular entity. Computational analysis suggested that this fusion signature was associated with estrogen receptor signaling. Functional studies demonstrated regulation of the TMPRSS2-ERG fusion transcript by estrogenic compounds. These data identify a previously unrecognized mechanism for regulation of the TMPRSS2-ERG, even in the absence of a functional androgen receptor, and thus may have broader implications in the treatment of prostate cancer. Keywords: Prostate cancer, Expression array, Illumina, gene fusion, TMPRSS2, ERG, Signatures, Estrogen
Project description:Castration-resistant prostate cancer (CRPC) is a frequently occurring disease with adverse clinical outcomes and limited therapeutic options. Here, we identify a novel role of methionine adenosyltransferase 2a (MAT2A) as a driver of the androgen-indifferent state in ERG fusion-positive CRPC. We show that MAT2A is upregulated in CRPC and cooperates with ERG in promoting cell plasticity, stemness and tumorigenesis. RNA, ATAC and ChIP sequencing coupled with mass spectrometry analysis of histone post-translational modifications show that MAT2A broadly impacts the transcriptional and epigenetic landscape. MAT2A enhances H3K4me2 at multiple genomic sites promoting the expression of pro-tumorigenic non-canonical AR target genes in CRPC models. Genetic and pharmacological inhibition of MAT2A in preclinical models reversed this transcriptional and epigenetic remodeling, promoting luminal differentiation and improving the response to AR and EZH2 inhibitors. This data reveals a previously unrecognized function of MAT2A in epigenetic reprogramming and a synthetic vulnerability to MAT2A inhibitors in ERG fusion-positive CRPC.
Project description:An aberrant androgen receptor (AR) transcriptional network underpins prostate cancer development. Even though the AR cistrome had been extensively studied in prostate cancers, information pertaining to the spatial architecture of the AR transcriptional circuitry remains limited due to the absence of an AR-associated chromatin interactome map. To resolve this, we utilized chromatin interaction analysis by paired-end tag (ChIA-PET) sequencing to profile AR-associated and ERG-associated long range chromatin interactions in an ERG fusion positive prostate cancer cell line. We identified ERG-associated long range chromatin interactions as an elemental component in the AR-associated chromatin interactome, acting in concert, to achieve coordinated regulation of AR target genes. In addition, we characterized the epigenetic signature of the AR/ERG anchor binding sites and implicated AR and ERG associated chromatin loopings for facilitating fusion gene formation in prostate cancers. Taken together, our results revealed the presence of an AR/ERG defined higher order chromatin structure exploited for driving prostate cancer progression.