Project description:Lineage plasticity is a major mechanism driving prostate cancer progression and antiandrogen therapy resistance. Deletions or mutations in phosphatase and tensin homolog (PTEN) and TP53 tumor suppressor genes have been linked to lineage plasticity in prostate cancer. Fusion-driven overexpression of the E-twenty-six transformation specific (ETS)-related gene (ERG), encoding an oncogenic transcription factor, is observed in approximately 50% of all prostate cancers, yet its role in prostate cell lineage determination remains elusive. Here we demonstrate that transgenic expression of prostate cancer-associated ERG blocks Pten and Trp53 mutation-induced decreased expression of Ar and its downstream target genes and loss of luminal epithelial cell identity in the mouse prostate. Integrative analyses of ERG chromatin-immunoprecipitation sequencing (ChIP-seq) and transcriptome data show that ERG suppresses expression of a subset of cell cycle-promoting genes and RB phosphorylation, which in turn causes repression of E2F1-mediated expression of non-epithelial lineage genes. Xenograft studies show that PTEN/TP53 double mutated prostate tumors are responsive to the cyclin-dependent kinase 4 or 6 (CDK4/6) inhibitor palbociclib, but resistant to the AR inhibitor enzalutamide, while ERG/PTEN/TP53 triple-mutated prostate tumors behave completely opposite. Our studies identify ERG and the repressed cell cycle gene signature as intrinsic inhibitors of PTEN/TP53 double mutation-elicited lineage plasticity in prostate cancer. Our findings also suggest that ERG fusion can be utilized as a biomarker to guide the treatment of PTEN/TP53-mutated, RB1-intact prostate cancer with either antiandrogen or anti-CDK4/6 therapies.
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: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: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:To determine if ERG expression and PTEN loss were sufficient to transform prostate epithelial cells we constructed cell lines with expression of the TMPRSS2/ERG fusion gene (TE), stable knockdown of PTEN with shRNA (PTEN KD) or both alterations (PTEN KD/TE) using the PNT1A cell line. To determine what gene expression changes are associated the phenotypic changes between the cell line experimental groups, we carried expression microarray studies using Agilent 60K expression microarrays. RNAs from all four cell lines were analyzed in duplicate and probes with ≥ 1.4-fold or ≤0.7-fold relative to control cells identified. Our results demonstrated that PTEN loss and expression of the TMPRSS2/ERG fusion gene transform prostatic epithelial cells via enhanced FGF signaling.
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:Antineoplastic effects of siRNA against TMPRSS2-ERG junction oncogene in prostate cancer: from molecular and cellular studies to preclinical investigations. Background of the study.:TMPRSS2-ERG junction oncogene is present in more than 50% of patients with prostate cancer, and its expression is frequently associated with poor prognosis. We knockdown by siRNA the two TMPRSS2-ERG fusion variants (III and IV) most frequently identified in patients’ biopsies and found an inhibition of TMPRSS2-ERG of above 70% in human prostate cancer VCaP cell line expressing TMPRSS2-ERG junction oncogene. To point out genes regulated after TMPRSS2-ERG oncogene silencing, microarray analysis was performed.. Materiel and Methods. Human prostate cancer VCaP cell line expressing TMPRSS2-ERG oncogene (ATCC® CRL-2876™ Manassas, USA) was grown in Dulbecco's Modified Eagle Medium (DMEM) (Invitrogen, Cergy-Pontoise, France) supplemented with 10% fetal bovine serum (FBS), 100 units/ml penicillin and 100 μg/ml streptomycin (Invitrogen). Cells were incubated at 37°C in a humidified atmosphere containing 5% CO2. Transfection was carried out using Lipofectamine RNAiMAX transfecting agent (Invitrogen) according to manufacturer's instructions. Briefly, 8×105 VCaP cells were seeded in six-well plates in DMEM supplemented with 10% FCS, penicillin (100U/ml) and streptomycin (10µg/ml) and transfected with 50 nM siRNA TMPRSS2-ERG III, siRNA TMPRSS2-ERG IV and siRNA Control and 6 μL Lipofectamine® RNAiMAX. Cells were incubated with siRNA for 48h. At the end of the treatments, total RNAs of untreated cells (NT) and transfected cells were extracted using RNeasy mini-kit (Quiagen, Courtaboeuf, France). Three independent experiments were performed. Results. Microarray analysis confirmed ERG inhibition by both siRNA TMPRSS2-ERG III and IV and revealed a common down-regulated gene, ADRA2A, involved in cell proliferation and migration. Experiments are performed with Agilent Whole Genome 8x60K (028004) microarray. In triplicate with a non treated control cells, a control with ascramble siRNA, a siRNA TMPRSS2-ERG III, a siRNA TMPRSS2 IV.
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: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.