Androgen regulated genes in human prostate xenografts in mice: relation to BPH and prostate cancer

The SPARC-related modular calcium binding 1 ( Smoc1 ) regulated by androgen is required for mouse gubernaculum development and testicular descent

ABSTRACT

Testicular descent occurs in two consecutive stages: the transabdominal stage and the inguinoscrotal stage. Androgens play a crucial role in the second stage by influencing the development of the gubernaculum, a structure that pulls the testis into the scrotum. However, the mechanisms of androgen actions underlying many of the processes associated with gubernaculum development have not been fully elucidated. To identify the androgen-regulated genes, we conducted large-scale gene expression analyses on the gubernaculum harvested from luteinizing hormone/choriogonadotropin receptor knockout ( Lhcgr KO) mice, an animal model of inguinoscrotal testis maldescent resulting from androgen deficiency. We found that the expression of secreted protein acidic and rich in cysteine (SPARC)-related modular calcium binding 1 ( Smoc1 ) was the most severely suppressed at both the transcript and protein levels, while its expression was the most dramatically induced by testosterone administration in the gubernacula of Lhcgr KO mice. The upregulation of Smoc1 expression by testosterone was curtailed by the addition of an androgen receptor antagonist, flutamide. In addition, in vitro studies demonstrated that SMOC1 modestly but significantly promoted the proliferation of gubernacular cells. In the cultures of myogenic differentiation medium, both testosterone and SMOC1 enhanced the expression of myogenic regulatory factors such as paired box 7 ( Pax7 ) and myogenic factor 5 ( Myf5 ). After short-interfering RNA-mediated knocking down of Smoc1 , the expression of Pax7 and Myf5 diminished, and testosterone alone did not recover, but additional SMOC1 did. These observations indicate that SMOC1 is pivotal in mediating androgen action to regulate gubernaculum development during inguinoscrotal testicular descent.

Establishing and Characterizing the Molecular Profiles, Cellular Features, and Clinical Utility of a Patient-Derived Xenograft Model Using Benign Prostatic Tissues

Benign prostatic hyperplasia (BPH) is a common condition marked by the enlargement of the prostate gland, which often leads to significant urinary symptoms and a decreased quality of life. The development of clinically relevant animal models is crucial for understanding the pathophysiology of BPH and improving treatment options. This study aims to establish a patient-derived xenograft (PDX) model using benign prostatic tissues to explore the molecular and cellular mechanisms of BPH. PDXs were generated by implanting fresh BPH (transition zone) and paired normal (peripheral zone) prostate tissue from 8 patients under the renal capsule of immunodeficient male mice. Tissue weight, architecture, cellular proliferation, apoptosis, prostate-specific marker expression, and molecular profiles of PDXs were assessed after 1 week and 1, 2, or 3 months of implantation by immunohistochemistry, enzyme-linked immunosorbent assay, transcriptomics, and proteomics. Responses to finasteride, a standard-of-care therapy, were evaluated. PDXs maintained histologic and molecular characteristics of the parental human tissues. BPH, but not normal PDXs, demonstrated significant increases in weight and cellular proliferation, particularly at 1 month. Molecular profiling revealed specific gene and protein expression patterns correlating with BPH pathophysiology. Specifically, an increased immune and stress response was observed at 1 week, followed by increased expression of proliferation markers and BPH-specific stromal signaling molecules, such as BMP5 and CXCL13, at 1 month. Graft stabilization to preimplant characteristics was apparent between 2 and 3 months. Treatment with finasteride reduced proliferation, increased apoptosis, and induced morphologic changes consistent with therapeutic responses observed in human BPH. Our PDX model recapitulates the morphologic, histologic, and molecular features of human BPH, offering a significant advancement in modeling the complex interactions of cell types in BPH microenvironments. These PDXs respond to therapeutic intervention as expected, providing a valuable tool for preclinical testing of new therapeutics that will improve the well-being of BPH patients.

Inhibiting CBP Decreases AR Expression and Inhibits Proliferation in Benign Prostate Epithelial Cells

(1) Background: CREB-binding protein (CBP) is a key transcriptional coactivator of androgen receptors (AR). We conducted this study to investigate the effects of CBP on AR expression and proliferation in benign prostatic hyperplasia (BPH) prostate epithelial cells. (2) Methods: By analyzing a published data set, we found that CBP was closely related to the gene expression of AR in prostate cells. We enrolled 20 BPH patients who underwent transurethral resection of the prostate (TURP) in Peking University First Hospital in 2022, and analyzed the expressions of CBP and AR in BPH prostate tissues. Then, we used ICG-001 and shRNA to inhibit CBP in prostate epithelial cells (BPH-1 cells and RWPE-1 cells), and conducted immunofluorescence, cell viability assay, flow cytometry analysis, and Western blot to analyze the effects of CBP on AR expression and proliferation in prostate epithelial cells. We also studied the interaction between CBP and AR through a co-immunoprecipitation assay. (3) Results: CBP is consistent with AR in expression intensity in prostate tissues. Inhibiting CBP decreases AR expression, and induces proliferation inhibition, apoptosis, and cell cycle arrest in BPH prostate epithelial cells. The co-immunoprecipitation assay showed that CBP binds with AR to form transcription complexes in prostate epithelial cells. (4) Conclusions: Inhibiting CBP decreases AR expression and inhibits proliferation in benign prostate epithelial cells. CBP may be a potential target to affect AR expression and the proliferation of prostate epithelial cells in BPH.

Multidirectional Effects of Terpenoids from Sorbus intermedia (EHRH.) PERS Fruits in Cellular Model of Benign Prostate Hyperplasia

Benign prostatic hyperplasia (BPH) is a common urological disease affecting aging men. Its pathogenesis is regarded as complex and multifactorial, with sex hormones and inflammation as key contributory factors. In the current study, we investigated the anti-BPH potential of terpenoids present in the fruits of Sorbus intermedia (EHRH.) PERS. Not only the effects on testosterone-stimulated normal prostate epithelial PNT2 cells, namely suppression of 5-α-reductase activity, PSA secretion, and cell proliferation, were determined but also the inhibitory activity on heat-induced protein denaturation, hyaluronidase, as well as IL-6, TNF-α, and NO release in LPS-treated macrophages. Sorbus terpenoids significantly inhibited 5-α-reductase activity and reduced PSA secretion in PNT2 cells, reversing the stimulatory effect of testosterone. PNT2 cell proliferation was also found to be attenuated. Subsequently, all compounds reduced the release of pro-inflammatory mediators in RAW 264.7 cells. In addition, ursolic acid (UA) and its aldehyde (UAL) were the most potent hyaluronidase inhibitors of all compounds, with IC₅₀ values of 225.75 µg/mL and 369.77 µg/mL, respectively. For better understanding and interpretation of the overall effect of Sorbus terpenoids on different aspects of BPH pathogenesis and development, cluster analysis was applied.

Signaling Pathways That Control Apoptosis in Prostate Cancer

Prostate cancer is the second most common malignancy and the fifth leading cancer-caused death in men worldwide. Therapies that target the androgen receptor axis induce apoptosis in normal prostates and provide temporary relief for advanced disease, yet prostate cancer that acquired androgen independence (so called castration-resistant prostate cancer, CRPC) invariably progresses to lethal disease. There is accumulating evidence that androgen receptor signaling do not regulate apoptosis and proliferation in prostate epithelial cells in a cell-autonomous fashion. Instead, androgen receptor activation in stroma compartments induces expression of unknown paracrine factors that maintain homeostasis of the prostate epithelium. This paradigm calls for new studies to identify paracrine factors and signaling pathways that control the survival of normal epithelial cells and to determine which apoptosis regulatory molecules are targeted by these pathways. This review summarizes the recent progress in understanding the mechanism of apoptosis induced by androgen ablation in prostate epithelial cells with emphasis on the roles of BCL-2 family proteins and "druggable" signaling pathways that control these proteins. A summary of the clinical trials of inhibitors of anti-apoptotic signaling pathways is also provided. Evidently, better knowledge of the apoptosis regulation in prostate epithelial cells is needed to understand mechanisms of androgen-independence and implement life-extending therapies for CRPC.

Animal models of benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) and associated lower urinary tract symptoms are common clinical concerns that affect aging men all over the world. The underlying molecular and cellular mechanisms remain elusive. Over the past few years, a number of animal models of BPH, including spontaneous model, BPH-induction model, xenograft model, metabolic syndrome model, mechanical obstruction model, and transgenic model, have been established that may provide useful tools to fill these critical knowledge gaps. In this review, we therefore outlined the present status quo for animal models of BPH, comparing the pros and cons with respect to their ability to mimic the etiological, histological, and clinical hallmarks of BPH and discussed their applicability for future research.

Amplification of a calcium channel subunit CACNG4 increases breast cancer metastasis

BACKGROUND

Previously, we found that amplification of chromosome 17q24.1-24.2 is associated with lymph node metastasis, tumour size, and lymphovascular invasion in invasive ductal carcinoma. A gene within this amplicon, CACNG4, an L-type voltage-gated calcium channel gamma subunit, is elevated in breast cancers with poor prognosis. Calcium homeostasis is achieved by maintaining low intracellular calcium levels. Altering calcium influx/efflux mechanisms allows tumour cells to maintain homeostasis despite high serum calcium levels often associated with advanced cancer (hypercalcemia) and aberrant calcium signaling.

METHODS

In vitro 2-D and 3-D assays, and intracellular calcium influx assays were utilized to measure tumourigenic activity in response to altered CANCG4 levels and calcium channel blockers. A chick-CAM model and mouse model for metastasis confirmed these results in vivo.

FINDINGS

CACNG4 alters cell motility in vitro, induces malignant transformation in 3-dimensional culture, and increases lung-specific metastasis in vivo. CACNG4 functions by closing the channel pore, inhibiting calcium influx, and altering calcium signaling events involving key survival and metastatic pathway genes (AKT2, HDAC3, RASA1 and PKCζ).

INTERPRETATION

CACNG4 may promote homeostasis, thus increasing the survival and metastatic ability of tumour cells in breast cancer. Our findings suggest an underlying pathway for tumour growth and dissemination regulated by CACNG4 that is significant with respect to developing treatments that target these channels in tumours with aberrant calcium signaling.

FUNDING

Canadian Breast Cancer Foundation, Ontario; Canadian Institutes of Health Research.

Genome-wide association study identifies nine novel loci for 2D:4D finger ratio, a putative retrospective biomarker of testosterone exposure in utero

The ratio of the length of the index finger to that of the ring finger (2D:4D) is sexually dimorphic and is commonly used as a non-invasive biomarker of prenatal androgen exposure. Most association studies of 2D:4D ratio with a diverse range of sex-specific traits have typically involved small sample sizes and have been difficult to replicate, raising questions around the utility and precise meaning of the measure. In the largest genome-wide association meta-analysis of 2D:4D ratio to date (N = 15 661, with replication N = 75 821), we identified 11 loci (9 novel) explaining 3.8% of the variance in mean 2D:4D ratio. We also found weak evidence for association (β = 0.06; P = 0.02) between 2D:4D ratio and sensitivity to testosterone [length of the CAG microsatellite repeat in the androgen receptor (AR) gene] in females only. Furthermore, genetic variants associated with (adult) testosterone levels and/or sex hormone-binding globulin were not associated with 2D:4D ratio in our sample. Although we were unable to find strong evidence from our genetic study to support the hypothesis that 2D:4D ratio is a direct biomarker of prenatal exposure to androgens in healthy individuals, our findings do not explicitly exclude this possibility, and pathways involving testosterone may become apparent as the size of the discovery sample increases further. Our findings provide new insight into the underlying biology shaping 2D:4D variation in the general population.

Genome-wide association study identifies nine novel loci for 2D:4D finger ratio, a putative retrospective biomarker of testosterone exposure in utero

The ratio of the length of the index finger to that of the ring finger (2D:4D) is sexually dimorphic and is commonly used as a non-invasive biomarker of prenatal androgen exposure. Most association studies of 2D:4D ratio with a diverse range of sex-specific traits have typically involved small sample sizes and have been difficult to replicate, raising questions around the utility and precise meaning of the measure. In the largest genome-wide association meta-analysis of 2D:4D ratio to date (N = 15 661, with replication N = 75 821), we identified 11 loci (9 novel) explaining 3.8% of the variance in mean 2D:4D ratio. We also found weak evidence for association (β = 0.06; P = 0.02) between 2D:4D ratio and sensitivity to testosterone [length of the CAG microsatellite repeat in the androgen receptor (AR) gene] in females only. Furthermore, genetic variants associated with (adult) testosterone levels and/or sex hormone-binding globulin were not associated with 2D:4D ratio in our sample. Although we were unable to find strong evidence from our genetic study to support the hypothesis that 2D:4D ratio is a direct biomarker of prenatal exposure to androgens in healthy individuals, our findings do not explicitly exclude this possibility, and pathways involving testosterone may become apparent as the size of the discovery sample increases further. Our findings provide new insight into the underlying biology shaping 2D:4D variation in the general population.

Targeting phenotypic heterogeneity in benign prostatic hyperplasia

Benign prostatic hyperplasia and associated lower urinary tract symptoms remain difficult to treat medically, resulting in hundreds of thousands of surgeries performed annually in elderly males. New therapies have not improved clinical outcomes since alpha blockers and 5 alpha reductase inhibitors were introduced in the 1990s. An underappreciated confounder to identifying novel targets is pathological heterogeneity. Individual patients display unique phenotypes, composed of distinct cell types. We have yet to develop a cellular or molecular understanding of these unique phenotypes, which has led to failure in developing targeted therapies for personalized medicine. This review covers the strategic experimental approach to unraveling the cellular pathogenesis of discrete BPH phenotypes and discusses how to incorporate these findings into the clinic to improve outcomes.

The androgen receptor plays different roles in macrophage-induced proliferation in prostate stromal cells between transitional and peripheral zones of benign prostatic hypertrophy

Macrophages play a critical role in the process of excessive stromal proliferation of benign prostatic hyperplasia (BPH). In our previous study, we used a BPH mouse model to elucidate a potential mechanism whereby macrophage infiltration promotes stromal cell proliferation in the prostate via the androgen receptor (AR)/inflammatory cytokine CCL3-dependent pathway. In our present study, we used the co-culture system of human macrophages and various prostatic zone stromal cells to further demonstrate that infiltrating macrophages promote prostatic stromal cell proliferation through stromal AR-dependent pathways, and we show that the stroma of TZ and PZ respond to macrophages differently because of differences in stromal AR signaling; this could possibly be one of the key pathways for stromal expansion during BPH development and progression. We hypothesize that AR and different downstream inflammatory mediators between TZ and PZ could serve as potential targets for the future design of therapeutic agents for BPH and our results provide significant insights into the search for targeted therapeutic approaches to battle BPH.

Cranberry intervention in patients with prostate cancer prior to radical prostatectomy. Clinical, pathological and laboratory findings

BACKGROUND AND OBJECTIVES

Recently, we described an inverse association between cranberry supplementation and serum prostate specific antigen (PSA) in patients with negative biopsy for prostate cancer (PCa) and chronic nonbacterial prostatitis. This double blind placebo controlled study evaluates the effects of cranberry consumption on PSA values and other markers in men with PCa before radical prostatectomy.

METHODS

Prior to surgery, 64 patients with prostate cancer were randomized to a cranberry or placebo group. The cranberry group (n=32) received a mean 30 days of 1500 mg cranberry fruit powder. The control group (n=32) took a similar amount of placebo. Selected blood/urine markers as well as free and total phenolics in urine were measured at baseline and on the day of surgery in both groups. Prostate tissue markers were evaluated after surgery.

RESULTS

The serum PSA significantly decreased by 22.5% in the cranberry arm (n=31, P<0.05). A trend to down-regulation of urinary beta-microseminoprotein (MSMB) and serum gamma-glutamyltranspeptidase, as well as upregulation of IGF-1 was found after cranberry supplementation. There were no changes in prostate tissue markers or, composition and concentration of phenolics in urine.

CONCLUSIONS

Daily consumption of a powdered cranberry fruit lowered serum PSA in patients with prostate cancer. The whole fruit contains constituents that may regulate the expression of androgen-responsive genes.

Detection of candidate biomarkers of prostate cancer progression in serum: a depletion-free 3D LC/MS quantitative proteomics pilot study

BACKGROUND

Prostate cancer (PCa) is the most common male cancer in the United Kingdom and we aimed to identify clinically relevant biomarkers corresponding to stage progression of the disease.

METHODS

We used enhanced proteomic profiling of PCa progression using iTRAQ 3D LC mass spectrometry on high-quality serum samples to identify biomarkers of PCa.

RESULTS

We identified >1000 proteins. Following specific inclusion/exclusion criteria we targeted seven proteins of which two were validated by ELISA and six potentially interacted forming an 'interactome' with only a single protein linking each marker. This network also includes accepted cancer markers, such as TNF, STAT3, NF-κB and IL6.

CONCLUSIONS

Our linked and interrelated biomarker network highlights the potential utility of six of our seven markers as a panel for diagnosing PCa and, critically, in determining the stage of the disease. Our validation analysis of the MS-identified proteins found that SAA alongside KLK3 may improve categorisation of PCa than by KLK3 alone, and that TSR1, although not significant in this model, might also be a clinically relevant biomarker.

Mice lacking β-carotene-15,15'-dioxygenase exhibit reduced serum testosterone, prostatic androgen receptor signaling, and prostatic cellular proliferation

β-Carotene-15,15'-dioxygenase (BCO1) cleaves dietary carotenoids at the central 15,15' double bond, most notably acting on β-carotene to yield retinal. However, Bco1 disruption also impacts diverse physiological end points independent of dietary carotenoid feeding, including expression of genes controlling androgen metabolism. Using the Bco1^-/- mouse model, we sought to probe the effects of Bco1 disruption on testicular steroidogenesis, prostatic androgen signaling, and prostatic proliferation. Male wild-type (WT) and Bco1^-/- mice were raised on carotenoid-free AIN-93G diets before euthanasia between 10 and 14 wk of age. Weights of the prostate and seminal vesicles were significantly lower in Bco1^-/- than in WT mice (-18% and -29%, respectively). Serum testosterone levels in Bco1^-/- mice were significantly reduced by 73%. Bco1 disruption significantly reduced Leydig cell number and decreased testicular mRNA expression of Hsd17b3, suggesting inhibition of testicular testosterone synthesis. Immunofluorescent staining of the androgen receptor (AR) in the dorsolateral prostate lobes of Bco1^-/- mice revealed a decrease in AR nuclear localization. Analysis of prostatic morphology suggested decreases in gland size and secretion. These findings were supported by reduced expression of the proliferation marker Ki-67 in Bco1^-/- prostates. Expression analysis of 200 prostate cancer- and androgen-related genes suggested that Bco1 loss significantly disrupted prostatic androgen receptor signaling, cell cycle progression, and proliferation. This is the first demonstration that Bco1 disruption lowers murine circulating testosterone levels and thereby reduces prostatic androgen receptor signaling and prostatic cellular proliferation, further supporting the role of this protein in processes more diverse than carotenoid cleavage.

Oral administration of low-dose bisphenol A promotes proliferation of ventral prostate and upregulates prostaglandin D2 synthase expression in adult rats

This study aims to assess the effect of low oral dose of bisphenol A (BPA) on proliferation of ventral prostate (VP) and expression of related genes in adult rats. Three-month-old male Sprague Dawley rats were treated daily with BPA (10, 30, or 90 µg/kg, per os), 17β-estradiol (E2, 10.0 µg/kg, subcutaneously), or vehicle for 4 weeks. Treatment with 10 µg/kg BPA resulted in increased animal weight and VP epithelial height compared with the controls ( p < 0.01), while such effects were less pronounced in higher BPA doses. Treatment with E2 showed opposite effects, with significantly decreased animal weight and VP epithelial height ( p < 0.01). Interestingly, BPA increased serum E2 and reduced testosterone levels and significantly increased the estrogen to androgen ratio ( p < 0.05). In addition, BPA slightly increased dihydrotestosterone (DHT) levels. Immunohistochemistry data showed that BPA significantly upregulated proliferating cell nuclear antigen expression ( p < 0.01). Furthermore, microarray and reverse transcription polymerase chain reaction analyses showed that BPA induced upregulation of prostaglandin D2 synthase ( Ptgds), Fas, Pbef1, and complement factor B ( Cfb)as well as downregulation of Pttg1 and Fabp4 in the VP. These results indicated that environmental exposure to low doses of BPA may induce proliferation of VP in adult rats by increasing the estrogen to androgen ratio and upregulating expression of Ptgds to promote production of DHT.

Reduction in expression of the benign AR transcriptome is a hallmark of localised prostate cancer progression

BACKGROUND

Despite the importance of androgen receptor (AR) signalling to prostate cancer development, little is known about how this signalling pathway changes with increasing grade and stage of the disease.

OBJECTIVE

To explore changes in the normal AR transcriptome in localised prostate cancer, and its relation to adverse pathological features and disease recurrence.

DESIGN

Publically accessible human prostate cancer expression arrays as well as RNA sequencing data from the prostate TCGA. Tumour associated PSA and PSAD were calculated for a large cohort of men (n=1108) undergoing prostatectomy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We performed a meta-analysis of the expression of an androgen-regulated gene set across datasets using Oncomine. Differential expression of selected genes in the prostate TCGA database was probed using the edgeR Bioconductor package. Changes in tumour PSA density with stage and grade were assessed by Student's t-test, and its association with biochemical recurrence explored by Kaplan-Meier curves and Cox regression.

RESULTS

Meta-analysis revealed a systematic decline in the expression of a previously identified benign prostate androgen-regulated gene set with increasing tumour grade, reaching significance in nine of 25 genes tested despite increasing AR expression. These results were confirmed in a large independent dataset from the TCGA. At the protein level, when serum PSA was corrected for tumour volume, significantly lower levels were observed with increasing tumour grade and stage, and predicted disease recurrence.

CONCLUSIONS

Lower PSA secretion-per-tumour-volume is associated with increasing grade and stage of prostate cancer, has prognostic relevance, and reflects a systematic perturbation of androgen signalling.

Influence of stromal-epithelial interactions on androgen action

Androgen receptor (AR) signaling is vital to the development and function of the prostate and is a key pathway in prostate cancer. AR is differentially expressed in the stroma and epithelium, with both paracrine and autocrine control throughout the prostate. Stromal-epithelial interactions within the prostate are commonly dependent on AR signaling and expression. Alterations in these pathways can promote tumorigenesis. AR is also expressed in normal and malignant mammary tissues. Emerging data indicate a role for AR in certain subtypes of breast cancer that has the potential to be exploited therapeutically. The aim of this review is to highlight the importance of these interactions in normal development and tumorigenesis, with a focus on the prostate and breast.

MiR-221 promotes the development of androgen independence in prostate cancer cells via downregulation of HECTD2 and RAB1A

Hormone-sensitive prostate cancer typically progresses to castration resistant prostate cancer (CRPC) after the androgen deprivation therapy. We investigated the impact of microRNAs (miRs) in the transition of prostate cancer to CRPC. MiR-221/-222 was highly expressed in bone metastatic CRPC tumor specimens. We previously demonstrated that transient overexpression of miR-221/-222 in LNCaP promoted the development of the CRPC phenotype. In current study, we show that stably overexpressing miR-221 confers androgen independent (AI) cell growth in LNCaP by rescuing LNCaP cells from growth arrest at G1 phase due to the lack of androgen. Overexpressing of miR-221 in LNCaP reduced the transcription of a subgroup of androgen-responsive genes without affecting the androgen receptor (AR) or AR-androgen integrity. By performing systematic biochemical and bioinformatical analyses, we identified two miR-221 targets, HECTD2 and RAB1A, which could mediate the development of CRPC phenotype in multiple prostate cancer cell lines. Downregulation of HECTD2 significantly affected the androgen-induced and AR-mediated transcription, and downregulation of HECTD2 or RAB1A enhances AI cell growth. As a result of the elevated expression of miR-221, expression of many cell cycle genes was altered and pathways promoting epithelial to mesenchymal transition/tumor metastasis were activated. We hypothesize that a major biological consequence of upregulation of miR-221 is reprogramming of AR signaling, which in turn may mediate the transition to the CRPC phenotype.

Genetic association suggests that SMOC1 mediates between prenatal sex hormones and digit ratio

Men and women differ statistically in the relative lengths of their index and ring fingers; and the ratio of these lengths has been used as a biomarker for prenatal testosterone. The ratio has been correlated with a wide range of traits and conditions including prostate cancer, obesity, autism, ADHD, and sexual orientation. In a genome-wide association study of 979 healthy adults, we find that digit ratio is strongly associated with variation upstream of SMOC1 (rs4902759: P = 1.41 × 10(-8)) and a meta-analysis of this and an independent study shows a probability of P = 1.5 × 10(-11). The protein encoded by SMOC1 has recently been shown to play a critical role in limb development; its expression in prostate tissue is dependent on sex hormones, and it has been implicated in the sexually dimorphic development of the gonads. We put forward the hypothesis that SMOC1 provides a link between prenatal hormone exposure and digit ratio.

Modulation of the hypoxic response following partial bladder outlet obstruction

PURPOSE

Tissue level hypoxia has been noted in animal models of partial bladder outlet obstruction. The key mechanisms linking hypoxia and obstruction induced bladder dysfunction remain unknown. 2-Methoxyestradiol is a natural derivative of 17β-estradiol and is currently used as an oncologic agent for its ability to regulate the hypoxia pathway. We investigated the ability of 2-methoxyestradiol to modulate the hypoxia response in a mouse model of bladder obstruction.

MATERIALS AND METHODS

A group of 5 to 6-week-old female C57BL/6 mice underwent oophorectomy and partial bladder outlet obstruction. Obstructed animals received a subcutaneous pellet of cholesterol placebo (7) or 2-methoxyestradiol plus cholesterol (7). Age matched controls underwent oophorectomy only (8). After 4 weeks the bladders of mice with partial bladder outlet obstruction and of unobstructed animals were harvested. Bladder sections (5 μm) were immunostained for Hypoxyprobe™-1, glucose transporter 1 and hypoxia inducible factor-1α. Real-time polymerase chain reaction was performed for hypoxia inducible factor-1α and lysyl oxidase. Statistical analysis was performed using 1-way ANOVA and the Wilcoxon rank sum test.

RESULTS

Immunostaining for glucose transporter 1 and Hypoxyprobe-1 revealed the presence of tissue hypoxia after partial bladder outlet obstruction. Immunostaining and real-time polymerase chain reaction demonstrated the up-regulation of hypoxia inducible factor-1α in mice after partial bladder outlet obstruction compared to controls (p = 0.0394). Although not statistically significant, a trend toward lower gene expression of hypoxia inducible factor-1α was seen in mice receiving 2-methoxyestradiol compared to placebo (p = 0.0625). Compared to placebo, 2-methoxyestradiol treatment increased lysyl oxidase expression (p = 0.007).

CONCLUSIONS

Murine partial bladder outlet obstruction resulted in hypoxia and up-regulation of the hypoxia inducible factor-1 pathway. Subcutaneous 2-methoxyestradiol administration attenuated this response and may be a viable tool to study the role of hypoxia after partial bladder outlet obstruction.

Androgen deprivation causes epithelial-mesenchymal transition in the prostate: implications for androgen-deprivation therapy

Androgen deprivation is currently a standard-of-care, first-line therapy for prostate cancer in the United States. Although this regimen effectively regresses androgen-dependent disease, relapse often occurs in an androgen-independent manner and is associated with poor prognosis. Such castration-resistant prostate cancer represents a major clinical challenge, and the mechanisms underlying castration resistance are not fully understood. Epithelial-mesenchymal transition (EMT) is a key developmental process and has also been implicated in cancer metastasis and therapeutic resistance in recent years. However, the factors contributing to EMT in human cancers remain unclear. Here, we show that both normal mouse prostate tissue and human LuCaP35 prostate tumor explants display an EMT as well as increased stem cell-like features following androgen deprivation. Importantly, we observed similar changes in mesenchymal features in prostate tumors from patients treated with androgen-deprivation therapy. In addition, we have delineated a feedback loop involving the androgen receptor and the Zeb1 transcription factor that seems to mediate this transition. In summary, we show for the first time that androgen deprivation induces EMT in both normal prostate and prostate cancer, revealing a potentially important consequence of a standard-of-care treatment for prostate cancer. This finding could have significant implications for second-line treatment strategies in this clinical setting.

Global gene expression profile induced by the UV-filter 2-ethyl-hexyl-4-trimethoxycinnamate (EHMC) in zebrafish (Danio rerio)

Residues of the UV-filter 2-ethyl-hexyl-4-trimethoxycinnamate (EHMC) are ubiquitously found in aquatic biota but potential adverse effects in fish are fairly unknown. To identify molecular effects and modes of action of EHMC we applied a gene expression profiling in zebrafish using whole genome microarrays. Transcriptome analysis and validation of targeted genes were performed after 14 days of exposure of male zebrafish. Concentrations of 2.2 μg/L and 890 μg/L EHMC lead to alteration of 1096 and 1137 transcripts, respectively, belonging to many pathways. Genes involved in lipid metabolism and estrogenic pathway (vtg1), lipid biosynthesis (ptgds), vitamin A metabolic process (rbp2a), DNA damage and apoptosis (gadd45b), and regulation of cell growth (igfbp1a) were investigated by qRT-PCR analysis in whole body, liver, brain and testis. The analysis showed tissue-specific gene profiles and revealed that EHMC slightly affects the transcription of genes involved in hormonal pathways including vtg1, esr1, esr2b, ar, cyp19b and hsd17β3.

Stromal upregulation of lateral epithelial adhesions: gene expression analysis of signalling pathways in prostate epithelium

Background

Stromal signalling increases the lateral cell adhesions of prostate epithelial cells grown in 3D culture. The aim of this study was to use microarray analysis to identify significant epithelial signalling pathways and genes in this process.

Methods

Microarray analysis was used to identify genes that were differentially expressed when epithelial cells were grown in 3D Matrigel culture with stromal co-culture compared to without stroma. Two culture models were employed: primary epithelial cells (ten samples) and an epithelial cell line (three experiments). A separate microarray analysis was performed on each model system and then compared to identify tissue-relevant genes in a cell line model.

Results

TGF beta signalling was significantly ranked for both model systems and in both models the TGF beta signalling gene SOX4 was significantly down regulated. Analysis of all differentially expressed genes to identify genes that were common to both models found several morphology related gene clusters; actin binding (DIAPH2, FHOD3, ABLIM1, TMOD4, MYH10), GTPase activator activity (BCR, MYH10), cytoskeleton (MAP2, MYH10, TMOD4, FHOD3), protein binding (ITGA6, CD44), proteinaceous extracellular matrix (NID2, CILP2), ion channel/ ion transporter activity (CACNA1C, CACNB2, KCNH2, SLC8A1, SLC39A9) and genes associated with developmental pathways (POFUT1, FZD2, HOXA5, IRX2, FGF11, SOX4, SMARCC1).

Conclusions

In 3D prostate cultures, stromal cells increase lateral epithelial cell adhesions. We show that this morphological effect is associated with gene expression changes to TGF beta signalling, cytoskeleton and anion activity.

Androgens and estrogens in benign prostatic hyperplasia: past, present and future

Benign prostatic hyperplasia (BPH) and associated lower urinary tract symptoms (LUTS) are common clinical problems in urology. While the precise molecular etiology remains unclear, sex steroids have been implicated in the development and maintenance of BPH. Sufficient data exists linking androgens and androgen receptor pathways to BPH and use of androgen reducing compounds, such as 5α-reductase inhibitors which block the conversion of testosterone into dihydrotestosterone, are a component of the standard of care for men with LUTS attributed to an enlarged prostate. However, BPH is a multifactorial disease and not all men respond well to currently available treatments, suggesting factors other than androgens are involved. Testosterone, the primary circulating androgen in men, can also be metabolized via CYP19/aromatase into the potent estrogen, estradiol-17β. The prostate is an estrogen target tissue and estrogens directly and indirectly affect growth and differentiation of prostate. The precise role of endogenous and exogenous estrogens in directly affecting prostate growth and differentiation in the context of BPH is an understudied area. Estrogens and selective estrogen receptor modulators (SERMs) have been shown to promote or inhibit prostate proliferation signifying potential roles in BPH. Recent research has demonstrated that estrogen receptor signaling pathways may be important in the development and maintenance of BPH and LUTS; however, new models are needed to genetically dissect estrogen regulated molecular mechanisms involved in BPH. More work is needed to identify estrogens and associated signaling pathways in BPH in order to target BPH with dietary and therapeutic SERMs.

Cyclic GMP signaling in rat urinary bladder, prostate, and epididymis: tissue-specific changes with aging and in response to Leydig cell depletion

Aging of the male reproductive system leads to changes in endocrine signaling and is frequently associated with the emergence of prostate hyperplasia and bladder dysfunctions. Recent reports highlight prostate and bladder as promising targets for therapeutic interventions with inhibitors of the cyclic GMP (cGMP)-degrading phosphodiesterase 5 (PDE5). However, the cGMP signaling system in these organs is as yet poorly characterized, and the possibility of age-related alterations has not been addressed. This study investigates key proteins of cGMP pathways in bladder, prostate, and epididymis of young (3 months) and old (23-24 months) Wistar rats. Local differences in the abundance of PDE5, soluble guanylyl cyclase (sGC) and particulate guanylyl cyclases (GC-A, GC-B), endothelial nitric oxide synthase, and cGMP-dependent protein kinase I (PRKG1 (cGKI)) revealed pronounced tissue-specific peculiarities. Although cGMP-generating enzymes were not affected by age in all organs, we recognized age-related decreases of PDE5 expression in bladder and a selective diminishment of membrane-associated PRKG1 in epididymis. In disagreement with published data, all cGMP pathway proteins including PDE5 are poorly expressed in prostate. However, prostatic PRKG1 expression increases with aging. Androgen withdrawal during temporary Leydig cell elimination induced a massive (>12-fold) upregulation of PRKG1 in prostate but not in other (penis and epididymis) androgen-dependent organs. These findings identify PRKG1 as a key androgen-sensitive signaling protein in prostate of possible importance for growth regulation. The elucidated effects may have significance for age-associated pathologies in the male lower-urinary tract.

ERG rearrangement is present in a subset of transition zone prostatic tumors

A majority of prostate cancers exhibit a recurrent gene rearrangement involving chromosome 21. In approximately 90% of cases, the rearrangement is characterized by fusion of the androgen-regulated gene TMPRSS2 with the oncogene ERG. A recent study suggested that TMPRSS2-ERG gene fusion is lacking in cancers arising from the transition zone of the prostate. A dominant transition zone cancer was detected in 62/397 (16%) patients who underwent radical prostatectomy at our institution and were reviewed and mapped by a single pathologist. In 46/62 specimens, a secondary tumor was identified in the peripheral zone of the prostate. A tissue microarray containing both transition and peripheral zone tumors was constructed and evaluated for gene fusion analysis. TMPRSS2-ERG fusion status was determined using a multicolor interphase fluorescence in situ hybridization assay for ERG break-apart. The median age of the patients was 59 years. Prostatectomy Gleason score was 6 in 21, 7 in 34, and ≥8 in 7 cases. Median tumor volume was 200 mm(2). TMPRSS2-ERG gene fusion was present in 7/59 (12%) transition zone, and in 12/35 (34%) peripheral zone tumors. Transition zone fusion-positive cases were larger than their negative counterparts. No significant correlation was found between fusion status and Gleason score or pathologic stage. Gene fusion through deletion occurred in 4/7 transition zone and 7/12 peripheral zone tumors. Transition zone prostate cancers are considered biologically and genetically different from peripheral zone tumors. Although ERG rearrangement is more common in peripheral zone tumors, we have detected TMPRSS2-ERG fusion in a subset of transition zone cancers (12%). The lower frequency of gene fusion in transition zone prostate cancer may suggest distinct molecular alterations from peripheral zone tumors and the association with a high tumor volume may indicate a growth advantage for transition zone tumors harboring the gene fusion. Further studies are necessary to confirm this hypothesis.