Project description:Recurrences of hormone-refractory prostate cancer highly affect the therapeutic outcome. Although anti-androgen therapy prolongs survival in prostate cancer patients, resistance rapidly develops and is often associated with increased androgen receptor expression and upregulated HER2/3-AKT signaling pathway. However, single agent therapy targeting AR, HER2/3 or AKT usually failed due to the reciprocal feedback loop. Here, we demonstrated that herbal extract of Wedelia chinensis (WCE) effectively disrupted the androgen receptor, HER2/3, and AKT signaling network and therefore enhanced therapeutic efficacy of androgen ablation in PCa.
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:Progression of prostate cancer -the most frequent cancer in men- is driven by androgen steroid hormones, and delayed by androgen deprivation therapy (ADT). Androgens control transcription in prostate cancer cells by stimulating androgen receptor (AR) activity, but also control pre-mRNA splicing through less clear mechanisms. Here we examine whether androgens regulate splicing through AR-mediated transcriptional control of splicing regulator proteins. Supporting this mechanism we find AR controls ESRP2, which encodes a key epithelial-specific splicing regulator. Both ESRP2 and its close paralog ESRP1 are highly expressed in primary prostate cancer, and slow growth of prostate cancer xenografts in mice. Androgen stimulation induces splicing switches in many endogenous ESRP2-controlled mRNA isoforms, including a key splicing switch in the metastatic regulator FLNB which is associated with disease relapse after treatment. ESRP2 expression in clinical prostate cancer is repressed by ADT, which may thus inadvertently dampen epithelial splice programmes. Supporting this, FLNB splicing was reciprocally switched by the AR antagonist Casodex®. Our data reveal a new mechanism of splicing control in prostate cancer with important implications for disease progression.
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:Despite the clinical benefit of androgen-deprivation therapy (ADT), the majority of patients with advanced prostate cancer (PCa) ultimately develop lethal castration-resistant prostate cancer (CRPC). In this study, we identified thioesterase superfamily member 6 (THEM6) as a marker of ADT resistance in PCa. In patients, THEM6 expression correlates with progressive disease and is associated with poor survival. THEM6 deletion reduces in vivo tumour growth and restores castration sensitivity in orthograft models of CRPC. Mechanistically, THEM6 is located at the endoplasmic reticulum (ER) membrane and controls lipid homeostasis by regulating intracellular levels of ether lipids. As a consequence, THEM6 loss in CRPC cells significantly alters ER function, preventing lipid-mediated induction of ATF4 and reducing de novo sterol biosynthesis. Finally, we show that THEM6 is required for the establishment of the MYC-induced stress response. Thus, similar to PCa, THEM6 loss significantly impairs tumorigenesis in the MYC-dependent subtype of triple negative breast cancer. Altogether our results highlight THEM6 as a novel component of the treatment-induced stress response and a promising target for the treatment of CRPC and MYC-driven cancer.
Project description:Activation of the inflammatory circuits occurs frequently in cancer cells. However the molecular details linking inflammation to transformation and progression are still unknown. In this study we report for the first time, that activation of the ETS factor ESE1 is a key event connecting inflammatory signaling with prostate cancer progression. We report that ESE1 is induced upon IL-1 beta stimulation by NFKB and mediates key transcriptional changes involving cell adhesion, migration and invasion. ESE1 activation in turn induces NFKB transcriptional activation and intranuclear translocation and mediates the transforming phenotypes linked to the activation of IL-1B. Transcriptional signatures and immunohistochemistry revealed that this ESE1-NFKB regulatory circuit also operates in prostate tumors, particularly in those with significant elevation of ESE1. Thus, ESE1 promotes an inflammatory feed forward loop positively leading to prostate cancer progression. Pharmacological NFKB inhibition reverted the transformed status of ESE1 cell lines providing a rationale for context-dependent therapeutic strategies in ESE1 activated tumors. These studies find a previously unrecognized link between ETS and activation of the NFKB pathway and open new avenues for prostate cancer treatment. Gene expression analysis of a control cell line (22Rv1-pcDNA3.1) and a testing cell lines (22Rv1-ESE1), with two replicates, with dye swap, performed for each sample.
Project description:In castration-resistant prostate cancer (CRPC), clinical response to androgen receptor (AR) antagonists is limited mainly due to AR-variants expression and restored AR signaling. The metabolite spermine is most abundant in prostate and it decreases as prostate cancer progresses, but its functions remain poorly understood. Here, we show spermine inhibits full-length androgen receptor (AR-FL) and androgen receptor splice variant 7 (AR-V7) signaling and suppresses CRPC cell proliferation by directly binding and inhibiting protein arginine methyltransferase PRMT1. Spermine reduces H4R3me2a modification at the AR locus and suppresses AR binding as well as H3K27ac modification levels at AR target genes. Spermine supplementation restrains CRPC growth in vivo. PRMT1 inhibition also suppresses AR-FL and AR-V7 signaling and reduces CRPC growth. Collectively, we demonstrate spermine as an anticancer metabolite by inhibiting PRMT1 to transcriptionally inhibit AR-FL and AR-V7 signaling in CRPC, and we indicate spermine and PRMT1 inhibition as powerful strategies overcoming limitations of current AR-based therapies in CRPC.
Project description:Prostate cancer development and progression relies on the programming of glucose and lipid metabolism, and this involves alterations in androgen receptor expression and signalling. Androgen deprivation therapy (ADT) provides short-term efficacy for patient treatment, but inevitably promotes a castration-resistant phenotype with poor prognosis. Defining the molecular mechanism that underpins this metabolic programming will have direct significance for prostate cancer patients who have poor expected outcomes and/or receive ADT. Here we show that there is a dynamic balance between sortilin and syndecan-1 that reports on different metabolic phenotypes. Sortilin, enhances glucose metabolism by regulating GLUT1 and GLUT4, while binding progranulin and lipoprotein lipase (LPL) to limit lipid metabolism. In contrast, syndecan-1 interacts with LPL and β3 integrin, to promote lipid metabolism and this process is upregulated in androgen-insensitive cells. We report a hitherto unappreciated molecular mechanism for prostate cancer, which has significance for disease progression and how ADT may promote castration-resistant prostate cancer.
Project description:Progression to androgen independent is the main cause of death in prostate cancer, and the mechanism is still unclear. By reviewing the expression profiles of 26 prostate cancer samples in a holistic view, we found a group of genes differentially expressed in androgen independent compared with androgen dependent groups (p value< 0.01, t test). Focusing on apoptosis, proliferation, hormone and angiogenesis, we found a group of genes such as thioredoxin domain containing 5 (TXNDC5), tumor necrosis factor receptor superfamily, member 10a (TNFRSF10A), ribosomal protein S19 (RPS19) and Janus kinase 2 (JAK2) up-regulated in androgen independent prostate cancer, which could play important roles in the transition from androgen dependent to androgen independent and could be biomarkers of prognosis. The main aim was comparing the androgen dependent and androgen independent prostate cancer to identify differentially expressed genes. In addition, we added several normal prostate tissue sample for comparisons. Totally 29 experiments were performed without replicates. 3 for normal prostate tissue, 8 for androgen independent cancer and 18 for androgen dependent prostate cancer. In all experiments, the reference samples are common reference, a pool with unrelated fetal tissues.