Project description:Deregulated expression of ETS transcription factors with oncogenic and tumor suppressor function occurs frequently in prostate cancer leading to profound alterations of the cancer transcriptome. By integrating genomic and functional studies we identified key targets of the aberrantly expressed ETS factors, ERG and ESE3. Altered expression of ETS factors led to the induction of the polycomb group protein EZH2 and silencing of the tumor suppressor Nkx3.1. Nkx3.1 was controlled by ERG and ESE3 both directly via binding to ETS binding sites in the gene promoter and indirectly via EZH2-induced histone H3K27 methylation. This may represent a general mechanism linking aberrantly expressed ETS with deregulation of epigenetic pathways and global reprogramming of the prostate epithelial cell transcriptome in prostate tumorigenesis. Keywords: prostate cancer, gene expression profiling, ETS genes In this study we show that deregulated expression of ETS factors with opposite functions is highly frequent in prostate cancer. Our study uncovers a previously unrecognized link between aberrant expression of ETS factors, deregulation of epigenetic pathways and silencing of tumor suppressor genes in prostate cancer and shows that partially distinct transcriptional programs are associated with different ETS gene expression patterns. The presence of distinct prostate cancer subgroups with different biological features may have important clinical implications and suggests that assessment of ETS expression levels might be useful to distinguish tumors with different clinical outcome.
Project description:Deregulated expression of ETS transcription factors with oncogenic and tumor suppressor function occurs frequently in prostate cancer leading to profound alterations of the cancer transcriptome. By integrating genomic and functional studies we identified key targets of the aberrantly expressed ETS factors, ERG and ESE3. Altered expression of ETS factors led to the induction of the polycomb group protein EZH2 and silencing of the tumor suppressor Nkx3.1. Nkx3.1 was controlled by ERG and ESE3 both directly via binding to ETS binding sites in the gene promoter and indirectly via EZH2-induced histone H3K27 methylation. This may represent a general mechanism linking aberrantly expressed ETS with deregulation of epigenetic pathways and global reprogramming of the prostate epithelial cell transcriptome in prostate tumorigenesis. Keywords: prostate cancer, gene expression profiling, ETS genes
Project description:ETS transcription factors have recently emerged as important elements in the pathogenesis of prostate cancer (PCa). ETS gene rearrangements leading to over-expression of ETS factors, like ERG, ETV1 and ETV4, are found in about 50% of prostate tumors. While the oncogenic potential of translocated ETS has been demonstrated in several contexts, the impact of endogenously expressed ETS factors on prostate tumorigenesis has been largely overlooked. Here we show that the epithelial-specific ETS factor ESE3, which is normally expressed in basal prostate epithelial (PrE) cells and frequently down-regulated in prostate tumors, serves as gatekeeper to maintain cell differentiation and its down-regulation leads to the acquisition of mesenchymal, stem cell (SC) and tumorigenic properties. ESE3 exerts this function by regulating critical genes involved in the epithelial to mesenchymal transition (EMT) and cell “stemness” and maintaining the equilibrium between cell differentiation and proliferation. Loss of ESE3 may be an important step in prostate tumorigenesis. Keywords: prostate epithelial cells, prostate cancer, gene expression profiling, ETS genes, EMT, cancer stem cells
Project description:Approximately 50% of prostate cancers have chromosomal translocations resulting in the over-expression one of four ETS family transcription factors. However, it is not known why these four four family members are selected for oncogenic roles, while other ETS proteins are not. We found that the four oncogenic ETS family members have a specific role in prostate cell migration. Using chromatin immunoprecipitation coupled with next-generation sequencing, this specific biological function was matched to a specific set of genomic targets highlighted by the presence of an AP-1 binding site. ETS/AP-1 binding sites are prototypical Ras-responsive elements, but oncogenic ETS proteins could activate a Ras/MAPK transcriptional program in the absence of MAPK activation. These findings indicate that the specific function of ETS proteins over-expressed in prostate cancer is the activation of a Ras/MAPK gene expression program in the absence of signaling pathway mutations. ChIP sequencing two transcription factors in PC3 cells, four transcription factors plus a FLAG control in RWPE-1 cells and input DNA sequencing from each cell line.
Project description:Approximately 50% of prostate cancers have chromosomal translocations resulting in the over-expression one of four ETS family transcription factors. However, it is not known why these four four family members are selected for oncogenic roles, while other ETS proteins are not. We found that the four oncogenic ETS family members have a specific role in prostate cell migration. Using chromatin immunoprecipitation coupled with next-generation sequencing, this specific biological function was matched to a specific set of genomic targets highlighted by the presence of an AP-1 binding site. ETS/AP-1 binding sites are prototypical Ras-responsive elements, but oncogenic ETS proteins could activate a Ras/MAPK transcriptional program in the absence of MAPK activation. These findings indicate that the specific function of ETS proteins over-expressed in prostate cancer is the activation of a Ras/MAPK gene expression program in the absence of signaling pathway mutations.
Project description:In prostate cancer, the androgen receptor (AR) is a key transcription factor at all disease stages. We recently showed that during progression to castrate-resistant prostate cancer the AR acquires the ability to bind to a distinct set of genomic sites in tissue samples and that some of the genes that are regulated by the AR in these conditions correlate with poor prognosis. Based on this work we hypothesised that the AR is reprogrammed through interactions with other transcription factors. In the present study we show that GABPá, an ETS transcription factor which is upregulated in CRPC, is an AR-interacting transcription factor. Ectopic expression of GABPA in prostate cancer cell-lines enables them to acquire some of the molecular and cellular characteristics of CRPC tissues as well as more aggressive growth phenotypes. VCaP prostate cancer cells and Jurkat lymphoma cells were studied for the ETS factors ERG and GABPa binding sites. Each sample was compared to its input.
Project description:This work was conducted to identify shared and specific target genes of different ETS transcription factor rearrangements in prostate cancer. Potential target genes were identified by differential gene expression analysis of primary tumor samples with ETS rearrangements, and validated by ETS silencing in prostate cancer cell lines. The series consists of 50 primary tumor samples from a consecutive series of 200 clinically localized cancers treated with radical prostatectomy at the Portuguese Oncology Institute, Porto, Portugal. The series is enriched in tumors with ETS transcription factor rearrangements
Project description:The tumor suppressor transcription factor p53 is mutated in nearly 50% of all cancer cases, and this frequency increases with stage and resistance to therapy. Hotspot p53 mutations lose direct DNA binding activity while gaining oncogenic function. These structural p53 mutants can bind to new regions of the genome via interactions with other transcription factors. One example is the ETS transcription factor ETS2, which was previously reported to bind mutant p53. Yet, a comprehensive understanding of mutant p53 association with the ETS family needs to be understood. Here, we compare mutant p53 interaction across 26 ETS transcription factors. Mutant p53 bound ETS proteins better than wild-type p53. All ETS proteins tested bound to mutant p53 to some extent, yet relative binding differed. The ETS DNA binding domain provided a common interaction interface, but strong binding required a second interaction domain. Genome-wide mapping found that the ETS protein ERG could recruit mutant p53 to regulatory regions of genes necessary for morphogenesis, locomotion, and androgen response in prostate cancer cells. Lastly, ETS factors that interact strongly with mutant p53 tend to be upregulated in p53 mutant ovarian cancer. These results suggest that multiple ETS proteins can work with mutant p53 in cancer.
Project description:Co-occurrence of aberrant hepatocyte growth factor (HGF)/MET proto-oncogene receptor tyrosine kinase (MET) and Wnt/β-catenin signaling pathways has been observed in advanced and metastatic prostate cancers. This co-occurrence positively correlates with prostate cancer progression and castration-resistant prostate cancer (CRPC) development. However, the biological consequences of these abnormalities in these disease processes remain largely unknown. Here, we investigated the aberrant activation of HGF/MET and Wnt/β-catenin cascades in prostate tumorigenesis by using a newly generated mouse model in which both murine Met transgene and stabilized β-catenin are conditionally co-expressed in prostatic epithelial cells. These compound mice displayed accelerated prostate tumor formation and invasion compared with their littermates that expressed only stabilized β-catenin.RNA-Seq and qRT-PCR analyses revealed increased expression of genes associated with tumor cell proliferation, progression,and metastasis. Moreover, Wnt signaling pathways were robustly enriched in prostate tumor samples from the compound mice.ChIP-qPCR experiments revealed increased β-catenin recruitment within the regulatory regions of the Myc gene in tumor cellsof the compound mice. Interestingly, the occupancy of MET on the Myc promoter also appeared in the compound mouse tumor samples,implicating a novel role of MET in β-catenin–mediated transcription. Results from implanting prostate graft tissues derived from the compound mice and controls into HGF-transgenic mice further uncovered that HGF induces prostatic oncogenic transformation and cell growth. These results indicate a role of HGF/MET in β-catenin–mediated prostate cancer cell growth and progressionand implicate a molecular mechanism whereby nuclear MET promotes aberrant Wnt/β-catenin signaling–mediated prostate tumorigenesis.
Project description:ERG activates prostate cancer specific gene expression program by recruiting RNA binding protein EWS to ETS-AP1 and GGAA microsatellite enhancers