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:A critical knowledge gap in prostate cancer research is understanding whether castration-tolerant progenitor-like cells that reside in treatment-naïve tumors play a direct role in therapy resistance and tumor progression. Herein, we reveal that the castration tolerance of LSCmed (Lin-, Sca-1+, CD49fmed) progenitor cells, the mouse equivalent of human prostatic Club cells, arises not from intrinsic properties but from significant transcriptional reprogramming. Utilizing single-cell RNA sequencing of LSCmed cells isolated from prostate-specific Pten-deficient (Ptenpc-/-) mice, we identify the emergence of castration-resistant LSCmed cells enriched in stem-like features, driven by the transcription factor Fosl1/AP-1. We demonstrate that cells exhibiting Ptenpc-/- LSCmed characteristics are prevalent in the aggressive mesenchymal stem-like prostate cancer (MSPC) subtype recently identified in human castration-resistant prostate cancer (CRPC). Furthermore, our findings show that the dual-targeting agents JQ-1 and CX-6258—focused on Fosl1/AP-1 and PIM kinases, respectively—effectively suppress both the progenitor properties and the growth of mouse and human MSPC surrogates in vitro and in vivo. Thus, early eradication of castration-tolerant Club-like cells presents a promising therapeutic strategy to mitigate prostate cancer progression toward CRPC.
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:Following extensive treatment with androgen receptor (AR) pathway inhibitors, a significant number of metastatic prostate cancer develop treatment resistance, and approximately 20% of these castration-resistant prostate cancers (CRPC) transdifferentiate, at least partially, into neuroendocrine (NE) prostate cancer (NEPC).In human cancer, FOXA2 is highly expressed in most of NEPC and a small portion of CRPC patients, has been suggested as a marker of NEPC and elevated in other NE lineage cancers including SCLC. In addition, preclinical studies demonstrated that Foxa2 is required for NEPC tumor growth and metastasis in TRAMP mouse model and associated with NEPC transformation in Pten, Trp53, and Rb1 triple knockout mouse model. However, whether FOXA2 is an essential driver of NEPC, and the underlying mechanism in shaping epigenetic landscape of NEPC is largely unknown.
Project description:Following extensive treatment with androgen receptor (AR) pathway inhibitors, a significant number of metastatic prostate cancer develop treatment resistance, and approximately 20% of these castration-resistant prostate cancers (CRPC) transdifferentiate, at least partially, into neuroendocrine (NE) prostate cancer (NEPC).In human cancer, FOXA2 is highly expressed in most of NEPC and a small portion of CRPC patients, has been suggested as a marker of NEPC and elevated in other NE lineage cancers including SCLC. In addition, preclinical studies demonstrated that Foxa2 is required for NEPC tumor growth and metastasis in TRAMP mouse model and associated with NEPC transformation in Pten, Trp53, and Rb1 triple knockout mouse model. However, whether FOXA2 is an essential driver of NEPC, and the underlying mechanism in shaping epigenetic landscape of NEPC is largely unknown.
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.