Project description:Alteration of the PTEN/PI3K pathway is associated with late stage and castrate resistant prostate cancer (CRPC). However, how PTEN loss involves in CRPC development is not clear. Here we show that castration-resistant growth is an intrinsic property of Pten-null prostate cancer (CaP) cells, independent of cancer development stage.PTEN loss suppresses androgen-responsive gene expressions by modulating androgen receptor (AR) transcription factor activity. Conditional deletion of AR in the epithelium promotes the proliferation of Pten-null cancer cells, at least in part, by down-regulating androgen-responsive gene FKBP5 and preventing PHLPP-mediated AKT inhibition. Our findings identify PI3K and AR pathway crosstalk as a mechanism of CRPC development, with potentially important implications for CaP etiology and therapy
Project description:Alteration of the PTEN/PI3K pathway is associated with late stage and castrate resistant prostate cancer (CRPC). However, how PTEN loss involves in CRPC development is not clear. Here we show that castration-resistant growth is an intrinsic property of Pten-null prostate cancer (CaP) cells, independent of cancer development stage.PTEN loss suppresses androgen-responsive gene expressions by modulating androgen receptor (AR) transcription factor activity. Conditional deletion of AR in the epithelium promotes the proliferation of Pten-null cancer cells, at least in part, by down-regulating androgen-responsive gene FKBP5 and preventing PHLPP-mediated AKT inhibition. Our findings identify PI3K and AR pathway crosstalk as a mechanism of CRPC development, with potentially important implications for CaP etiology and therapy Mouse embryonic fibroblasts (MEFs) carrying a tet-inducible Pten transgene were generated by retro viral infection and antibiotic selection. Cells were treated with 2 ug/ml doxycycline for 24 or 48 hours in tet-free FBS (5%)/MEF media (n=2). Reference samples were either cells before treatment (n=2). After each time point cells were washed twice with PBS and RNA trizol extracted. WT samples (n =2) were also included as a control.
Project description:PTEN is one of the most altered tumor suppressor genes in human prostate cancer (PCa). Prostate specific-Pten-deficient mouse models develop prostate cancer eventually progressing to castration-resistant prostate cancer (CRPC), also due to alterations of the tumor immune infiltrate. By using single-cell RNA-seq, we report the identification of a subset of CD84+; CD11b+; Ly6G+; Ly6Clow immunosuppressive neutrophils that secreted the coagulation factor X (FX) into the prostate TME to directly promote PCa growth.
Project description:PB-Cre/Pten/Smad4 is a transgenic mouse model of metastatic prostate adenocarcinoma (PMID: 21289624). To study the transcriptomic alterations associated with castration-resistant prostate cancer (CRPC), the PB-Cre/Pten/Smad4 males with established prostate cancer were treated with surgical castration followed by enzalutamide-admixed diet. After about 4 weeks, dorsolateral prostate (DLP) lobes of treatment-naïve prostate tumors (N=2) and CRPC tumors (N=3) were harvested and extracted for RNA purification and microarray profiling. To further study the transcriptomic changes associated with lung metastases of the PB-Cre/Pten/Smad4/mTmG CRPC model, the PB-Cre/Pten/Smad4 males with established prostate cancer were treated with surgical castration followed by enzalutamide-admixed diet. About 3 months later, from one mouse anterior prostate (AP), dorsolateral prostate (DLP), ventral prostate (VP) and GFP+ lung metastasis nodules were each harvested for RNA purification and microarray profiling.
Project description:Castration-resistant prostate cancer is a lethal disease. The cell type(s) that survive androgen-deprivation remain poorly described despite global efforts to understand the various mechanisms of therapy resistance. We recently identified in wild type mouse prostates a rare population of luminal progenitor cells that we called LSCmed according to their FACS profile (Lin?/Sca-1+/CD49fmed). Here we investigated the prevalence and castration resistance of LSCmed in various mouse models of prostate tumorigenesis. In intact mice, we show that LSCmed prevalence remains low (5-10% of epithelial cells) when prostatic androgen receptor signaling unaltered (malignant Hi-Myc mice) but significantly increases in models exhibiting reduced prostatic androgen receptor signaling, rising up to 30% in premalignant tumors (Pb-PRL mice) and to >80% in castration-resistant prostate tumors driven by Pten loss (Ptenpc-/- mice). LSCmed tolerance to androgen deprivation was demonstrated by their persistence (Ptenpc-/-) or further enrichment (Pb-PRL) 2-3 weeks after castration as evidenced by FACS analysis. Transcriptomic analysis revealed that LSCmed represent a unique cell entity as their gene-expression profile is different from luminal and basal/stem cells, but shares markers of each. Their intrinsic androgen signaling is markedly decreased, which explains why LSCmed tolerate androgen-deprivation. This also enlightens why Ptenpc-/- tumors are castration-resistant since LSCmed represent the most prevalent cell type in this model. We validated CK4 as a specific marker for LSCmed on sorted cells and prostate tissues by immunostaining, allowing for the detection of LSCmed in various mouse prostate specimens. In castrated Ptenpc-/- prostates, BrdU staining revealed massive proliferation of CK4+ cells, further demonstrating their key role in castration-resistant prostate cancer progression. In all, this study identifies LSCmed as a probable source of prostate cancer relapse after androgen deprivation and as a new therapeutic target for the prevention of castrate-resistant prostate cancer.
Project description:The Tripartite motif-containing 28 (TRIM28) transcription factor is upregulated in high-grade prostate cancers and was recently proposed as a therapeutic target for castration-resistant prostate cancers. To study the role of TRIM28 in prostate cancer progression in vivo, we used a genetically engineered mouse model, combining prostate-specific Trim28 inactivation with inactivation of Trp53 and Pten. We analyzed the prostates using single cell RNA-Seq.
Project description:Chromosomal rearrangements involving ETS factors, ERG and ETV1, occur frequently in prostate cancer. How these factors contribute to tumorigenesis and whether they play similar in vivo roles remain elusive. We show that ERG and ETV1 control a common transcriptional network but in an opposing fashion. In mice with ERG or ETV1 targeted to the endogenous Tmprss2 locus, either factors cooperated with Pten-loss, leading to localized cancer, but only ETV1 supported development of advanced adenocarcinoma, likely through enhancement of androgen receptor signaling and steroid biosynthesis. Indeed, ETV1 expression promotes autonomous testosterone production, which may contribute to tumor progression to castration-resistant prostate cancer. Patient data confirmed association of ETV1 expression with aggressive disease. We conclude that despite many shared targets, ERG and ETV1 contribute differently to prostate tumor biology. Hence, prostate cancers with these fusions should be considered as distinct subtypes for patient stratification and therapy. Genomic targets of ERG and ETV1 transcription factors were identified by antibody-mediated and biotin-mediated ChIP-chip in human VCaP and LNCaP cells, respectively.
Project description:Incurable metastatic castration-resistant prostate cancer (CRPC) eventually occurs after androgen deprivation treatment. It is important to understand how CRPC initiates/progress. We generated a mouse androgen-independent prostate cancer cell line (PKO) from PTEN null and Hi-Myc transgenic mice in C57BL/6 background. Here we analyzed the expression profiles of PKO cells.
Project description:More effective therapeutic approaches for castration-resistant prostate cancer (CRPC) are urgently needed, thus reinforcing the need to understand how prostate tumors progress to castration resistance. We have established a novel mouse xenograft model of prostate cancer, KUCaP-2, which expresses the wild-type androgen receptor (AR) and which produces the prostate-specific antigen (PSA). In this model, tumors regress soon after castration, but then reproducibly restore their ability to proliferate after 1 to 2 months without AR mutation, mimicking the clinical behavior of CRPC. In the present study, we used this model to identify novel therapeutic targets for CRPC. Evaluating tumor tissues at various stages by gene expression profiling, we discovered that the prostaglandin E receptor EP4 subtype (EP4) was significantly upregulated during progression to castration resistance. Immunohistochemical results of human prostate cancer tissues confirmed that EP4 expression was higher in CRPC compared with hormone-naïve prostate cancer. Ectopic overexpression of EP4 in LNCaP cells (LNCaP-EP4 cells) drove proliferation and PSA production in the absence of androgen supplementation in vitro and in vivo. Androgen-independent proliferation of LNCaP-EP4 cells was suppressed when AR expression was attenuated by RNA interference. Treatment of LNCaP-EP4 cells with a specific EP4 antagonist, ONO-AE3-208, decreased intracellular cyclic AMP levels, suppressed PSA production in vitro, and inhibited castration-resistant growth of LNCaP-EP4 or KUCaP-2 tumors in vivo. Our findings reveal that EP4 overexpression, via AR activation, supports an important mechanism for castration-resistant progression of prostate cancer. Furthermore, they prompt further evaluation of EP4 antagonists as a novel therapeutic modality to treat CRPC. 4 samples in each group: androgen-dependent growth (AD), castration-induced regression nadir (ND), and castration-resistant regrowth (CR) stages
Project description:Castrate-resistant prostate cancer (CRPC) is poorly characterized and heterogeneous and while the androgen receptor (AR) is of singular importance, other factors such as c-Myc and the E2F family also play a role in later stage disease. Here we show that Hes6 is up-regulated in aggressive human prostate cancer and drives castration-resistant tumour growth in the absence of ligand binding by enhancing the transcriptional activity of the AR, which is preferentially directed to a regulatory network enriched for other transcription factors including E2F1. In the clinical setting, we have uncovered a Hes6-associated signature that predicts poor outcome in prostate cancer, which can be pharmacologically targeted with restoration of sensitivity to castration. AR and E2F1 ChIPseq from multiple simultaneous LNCaP cell replicates with and without bicalutamide