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: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: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:MicroRNAs (miRNAs) play important roles in cell differentiation and self-renewal controlling post-transcriptional processing of mRNAs and attenuating production of the encoded proteins. Here, we unveil a novel oncogenic pathway leading to activation of STAT3 signaling through miRNA-mediated silencing of the E3 ubiquitin ligase COP1. miRNA profiling showed that miR-424 was upregulated in prostate cancer compared to normal prostate and specifically associated with reduced level of the ETS factor ESE3/EHF in an aggressive subgroup of tumors. MiR-424 was significantly elevated also in other epithelial cancers and amplified in 1-3% of various cancers. In normal prostate epithelial cells miR-424 was repressed by ESE3/EHF and when upregulated promoted oncogenic and cancer stem cell (CSC) properties. Conversely, ablation of miR-424 in metastatic prostate cancer cells reduced CSC self-renewal and prevented in vivo tumour initiation and metastatic spread. miR-424 targeted the 3' UTR of COP1 mRNA and reduced COP1 protein level. COP1 induced STAT3 ubiquitylation and degradation by the ubiquitin-proteasome system (UPS). Therefore, reduced levels of COP1 in prostate cancer cells, resulted in accumulation and increased STAT3 signaling. COP1 knockdown and over-expression phenocopied the effects of miR-424 deregulation on oncogenic phenotypes and STAT3 signalling, while STAT3 knockdown prevented the transforming effects of miR-424. Consistently, expression of EHF/ESE3 and RFWD2/COP1 were highly correlated in human prostate cancers and other epithelial tumors. Furthermore, miR-424 induced genes were enriched of STAT3 targets, converged with those induced by COP1 loss in mouse embryos and were associated with adverse prognosis in prostate and other epithelial cancers. In primary prostate tumours, low COP1 and high STAT3 protein level were also significantly associated and predictive of biochemical relapse. Collectively, this study reveals a novel miRNA-activated oncogenic axis in prostate cancer. Targeting miR-424 or miR-424 dependent pathways may represent a unique approach to attack a key node in tumorigenesis.
Project description:MicroRNAs (miRNAs) play important roles in cell differentiation and self-renewal controlling post-transcriptional processing of mRNAs and attenuating production of the encoded proteins. Here, we unveil a novel oncogenic pathway leading to activation of STAT3 signaling through miRNA-mediated silencing of the E3 ubiquitin ligase COP1. miRNA profiling showed that miR-424 was upregulated in prostate cancer compared to normal prostate and specifically associated with reduced level of the ETS factor ESE3/EHF in an aggressive subgroup of tumors. MiR-424 was significantly elevated also in other epithelial cancers and amplified in 1-3% of various cancers. In normal prostate epithelial cells miR-424 was repressed by ESE3/EHF and when upregulated promoted oncogenic and cancer stem cell (CSC) properties. Conversely, ablation of miR-424 in metastatic prostate cancer cells reduced CSC self-renewal and prevented in vivo tumour initiation and metastatic spread. miR-424 targeted the 3' UTR of COP1 mRNA and reduced COP1 protein level. COP1 induced STAT3 ubiquitylation and degradation by the ubiquitin-proteasome system (UPS). Therefore, reduced levels of COP1 in prostate cancer cells, resulted in accumulation and increased STAT3 signaling. COP1 knockdown and over-expression phenocopied the effects of miR-424 deregulation on oncogenic phenotypes and STAT3 signalling, while STAT3 knockdown prevented the transforming effects of miR-424. Consistently, expression of EHF/ESE3 and RFWD2/COP1 were highly correlated in human prostate cancers and other epithelial tumors. Furthermore, miR-424 induced genes were enriched of STAT3 targets, converged with those induced by COP1 loss in mouse embryos and were associated with adverse prognosis in prostate and other epithelial cancers. In primary prostate tumours, low COP1 and high STAT3 protein level were also significantly associated and predictive of biochemical relapse. Collectively, this study reveals a novel miRNA-activated oncogenic axis in prostate cancer. Targeting miR-424 or miR-424 dependent pathways may represent a unique approach to attack a key node in tumorigenesis.
Project description:PDEF(Prostate Derived Ets factor) is a member of Ets transcription factor with specific expression in Prostate. We identified target genes for PDEF in prostate cancer cell line PC-3 using Affymetrix Genechip Microarray technology. Keywords: target gene identification for transcription factor
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: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.