Project description:Deregulation of the Androgen Receptor (AR) transcriptional network is a common hallmark in prostate cancers. To achieve its precise transcriptional role, AR needs to co-operate specifically with a plethora of cofactors. In prostate cancers, AR transcription collaborators are frequently aberrantly over-expressed, altering the AR signaling pathway to one that promotes oncogenesis. Recently, the prostate cancer recurrent fusion gene, ERG, was shown to promote tumor progression by acting as a repressor of AR signaling. However, the exact mechanics and the functional consequences associated with this crosstalk between ERG and AR still remains relatively unknown. Interestingly, through chromatin immunoprecipitation coupled with massively parallel sequencing, we discover that ERG and other commonly over-expressed transcriptional co-repressors (HDAC1, HDAC2, HDAC3 and EZH2) are wired into an AR-centric transcriptional network via a spectrum of distal enhancers and/or proximal promoters. We show that ERG represses several AR target genes involved in epithelial differentiation. Furthermore, we demonstrated that suppression of the androgen-induced gene, Vinculin, by ERG and histone deacetylases increases cancer cell invasiveness. From our results, we propose that ERG, histone deactelyases and the histone methyltransferase, EZH2, could impede epithelial differentiation and contribute to prostate cancer progression, in part through modulating the transcriptional output of AR. Genome-wide binding analysis of AR, ERG, HDAC1, HDAC2, HDAC3 and EZH2 in VCaP with and without DHT (dihydrotestosterone) stimulation using ChIP-Seq. 15 samples including 1 control (input).
Project description:TMPRSS2-ERG fusion is the most common genetic alteration in prostate cancer (PCa) and TP53 is the most frequently mutated gene in human cancers. However, their precise roles in PCa pathogenesis remain elusive. Here we showed that TMPRSS2-ERG fusion co-occurred with TP53 deletion/mutation in PCa patient specimens. ERG overexpression and Trp53 knockout/R172H mutant knockin induced pyrimidine synthesis gene (PSG) expression and prostate tumorigenesis in mice. Gain-of-function p53 mutants bound to the CTNNB1 promoter and upregulated β-Catenin. Overexpressed ERG and β-Catenin co-occupied PSG loci and mediated PSG expression, and high PSG expression associated with increased β-Catenin level and poor overall survival of PCa patients. β-Catenin inhibition by proteolysis-targeting chimeras (PROTACs) of its co-activator CBP and partner proteins LEF1/TCFs blocked ERG/p53-mutant PCa growth. Our study identifies CTNNB1 as a transcriptional target of p53 GOF-mutants, and reveals a druggable dependency on β-Catenin and pyrimidine synthesis in p53-mutated cancers with or without TMPRSS2-ERG fusion.
Project description:The TMPRSS2-ERG gene fusion is the most frequent alteration observed in human prostate cancer but its role in disease progression is still debated. In this study, we uncovered a novel molecular mechanism promoting progression in ERG-fusion positive prostate cancer. We show that ERG is methylated by Enhancer of zest homolog 2 (EZH2) at a specific lysine residue (K362) located within the internal auto-inhibitory domain. Mechanistically, K362 mono- methylation prevents intra-domain interactions, favors DNA binding and promotes ERG transcriptional and oncogenic activity in cellular and mouse models. Consistently with the involvement in ERG oncogenesis, we found that K362 methylation was associated with disease progression in ERG transgenic mouse models and was enhanced by PTEN deficiency and AKT activation, which promoted EZH2 substrate switching from histone H3K27 to ERG. Conversely, EZH2 inhibition blocked ERG methylation along with ERG-induced transcriptional and phenotypic reprogramming in cell cultures and ERG/PTEN mice. We found that ERG and EZH2 co-occupy several genomic regions forming prevalently co-activating complexes. The network of ERG/EZH2 co-regulated target genes was enriched of functionally aggressive features and was associated preferentially with concomitant ERG gain and PTEN loss, castration-resistance and adverse clinical outcome in prostate cancer patients. Collectively, these findings identify ERG methylation as a novel post-translational modification sustaining disease progression in ERG-positive prostate cancers. Our data also provide an attractive rationale for developing molecularly targeted therapeutics to antagonize ERG oncogenic activity.
Project description:Deregulation of the Androgen Receptor (AR) transcriptional network is a common hallmark in prostate cancers. To achieve its precise transcriptional role, AR needs to co-operate specifically with a plethora of cofactors. In prostate cancers, AR transcription collaborators are frequently aberrantly over-expressed, altering the AR signaling pathway to one that promotes oncogenesis. Recently, the prostate cancer recurrent fusion gene, ERG, was shown to promote tumor progression by acting as a repressor of AR signaling. However, the exact mechanics and the functional consequences associated with this crosstalk between ERG and AR still remains relatively unknown. Interestingly, through chromatin immunoprecipitation coupled with massively parallel sequencing, we discover that ERG and other commonly over-expressed transcriptional co-repressors (HDAC1, HDAC2, HDAC3 and EZH2) are wired into an AR-centric transcriptional network via a spectrum of distal enhancers and/or proximal promoters. We show that ERG represses several AR target genes involved in epithelial differentiation. Furthermore, we demonstrated that suppression of the androgen-induced gene, Vinculin, by ERG and histone deacetylases increases cancer cell invasiveness. From our results, we propose that ERG, histone deactelyases and the histone methyltransferase, EZH2, could impede epithelial differentiation and contribute to prostate cancer progression, in part through modulating the transcriptional output of AR. Gene expression profiling of human prostate cancer VCaP cells with time-course dihydrotestosterone (DHT) stimulation using microarrays. Triplicates were generated for each treatment/time point.
Project description:Deregulation of the Androgen Receptor (AR) transcriptional network is a common hallmark in prostate cancers. To achieve its precise transcriptional role, AR needs to co-operate specifically with a plethora of cofactors. In prostate cancers, AR transcription collaborators are frequently aberrantly over-expressed, altering the AR signaling pathway to one that promotes oncogenesis. Recently, the prostate cancer recurrent fusion gene, ERG, was shown to promote tumor progression by acting as a repressor of AR signaling. However, the exact mechanics and the functional consequences associated with this crosstalk between ERG and AR still remains relatively unknown. Interestingly, through chromatin immunoprecipitation coupled with massively parallel sequencing, we discover that ERG and other commonly over-expressed transcriptional co-repressors (HDAC1, HDAC2, HDAC3 and EZH2) are wired into an AR centric transcriptional network via a spectrum of distal enhancers and/or proximal promoters. We show that ERG represses several AR target genes involved in epithelial differentiation. Furthermore, we demonstrated that suppression of the androgen induced gene, Vinculin, by ERG and histone deacetylases increases cancer cell invasiveness. From our results, we propose that ERG, histone deactelyases and the histone methyltransferase, EZH2, could impede epithelial differentiation and contribute to prostate cancer progression, in part through modulating the transcriptional output of AR. Gene expression profiling of human prostate cancer VCaP cells with time course DHT stimulation using microarray.
Project description:Deregulation of the Androgen Receptor (AR) transcriptional network is a common hallmark in prostate cancers. To achieve its precise transcriptional role, AR needs to co-operate specifically with a plethora of cofactors. In prostate cancers, AR transcription collaborators are frequently aberrantly over-expressed, altering the AR signaling pathway to one that promotes oncogenesis. Recently, the prostate cancer recurrent fusion gene, ERG, was shown to promote tumor progression by acting as a repressor of AR signaling. However, the exact mechanics and the functional consequences associated with this crosstalk between ERG and AR still remains relatively unknown. Interestingly, through chromatin immunoprecipitation coupled with massively parallel sequencing, we discover that ERG and other commonly over-expressed transcriptional co-repressors (HDAC1, HDAC2, HDAC3 and EZH2) are wired into an AR-centric transcriptional network via a spectrum of distal enhancers and/or proximal promoters. We show that ERG represses several AR target genes involved in epithelial differentiation. Furthermore, we demonstrated that suppression of the androgen-induced gene, Vinculin, by ERG and histone deacetylases increases cancer cell invasiveness. From our results, we propose that ERG, histone deactelyases and the histone methyltransferase, EZH2, could impede epithelial differentiation and contribute to prostate cancer progression, in part through modulating the transcriptional output of AR.
Project description:ERG is a transcriptional factor, which is recombined with promoter of TMPRSS2 and prominently overexpressed in half of human prostate cancers. The mechanisms of ERG-mediated oncogenesis are not completely understood. We performed an unbiased Mass Spectrometry screen for ERG-binding proteins and found that ERG binds to MTDH/SND1 protein complex in prostate cancer cells. We determined that ERG binds to the SND1/MTDH protein complex via SND1 and this interaction plays a critical role in ERG-mediated cancer.
Project description:Fusion proteins involving the ETS factor ERG have been associated with multiple cancers such as Ewing's sarcoma and prostate cancer. In acute myeloid leukemias harboring t(16;21) another ERG fusion protein is expressed, FUS-ERG. Here, we found that this FUS-ERG oncofusion protein acts in the context of a heptad of proteins (ERG, FLI1, GATA2, LYL1, LNMO2, RUNX1 and TAL1) central to proper expression of genes involved in maintaining a stem cell hematopoietic phenotype. Moreover, in t(16;21) FUS-ERG co-occupies genomic regions bound by the nuclear receptor heterodimer RXR-RARA inhibiting target gene expression and interfering with hematopoietic differentiation. All-Trans Retinoic Acid treatment of t(16;21) cells as well as FUS-ERG knock down alleviate the myeloid differentiation block. Together, the results suggest that FUS-ERG acts as a transcriptional repressor of the retinoic acid signaling pathway. Cell lines were used for RNA extraction for RNA-seq and ChIP experiments for ChIP-seq.