Proliferation and phenotypic changes of stromal cells in response to varying estrogen/androgen levels in castrated rats

Traditional Chinese Medicine Danzhi qing'e decoction inhibits inflammation-associated prostatic hyperplasia via inactivation of ERK1/2 signal pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Inflammation plays a critical role during benign prostatic hyperplasia (BPH) development. Danzhi qing'e (DZQE) decoction is a traditional Chinese medicine that has been widely used for estrogen and androgen-related diseases. However, its effect on inflammation-related BPH remains unclear.

AIM OF THE STUDY

To investigate the effect of DZQE on inhibition of inflammation-related BPH, and further identify the possible mechanism involved.

METHODS AND MATERIALS

Experimental autoimmune prostatitis (EAP)-induced BPH was established and then 2.7 g/kg of DZQE was administrated orally for 4 weeks. The prostate sizes, weights and prostate index (PI) values were recorded. Hematoxylin and eosin (H&E) was performed for pathological analyses. Macrophage infiltrate was evaluated by Immunohistochemical (IHC). The inflammatory cytokine levels were measured by Rt-PCR and ELISA methods. The phosphorylation of ERK1/2 was examined by Western blot. The expression differences of mRNA expressions between EAP-induced and oestrogen/testosterone (E2/T)-induced BPH was investigated by RNA sequencing analyses. In vitro, human prostatic epithelial BPH-1 cells were stimulated with the conditioned medium from monocyte THP-1-derived M2 macrophages (M2CM), followed by treatment of Tanshinone IIA (Tan IIA), Bakuchiol (Ba), ERK1/2 antagonist PD98059 or ERK1/2 agonist C6-Ceramide. The ERK1/2 phosphorylation and cell proliferation were then detected by Western blotting and CCK8 assay.

RESULTS

DZQE significantly inhibited the prostate enlargement and decreased PI value in EAP rats. Pathological analysis showed that DZQE alleviated prostate acinar epithelial cell proliferation by decreasing and reduction of CD68⁺ and CD206⁺ macrophage infiltration in the prostate. The levels of cytokines TNF-α, IL-1β, IL-17, MCP-1, TGF-β, and IgG in EAP rats' prostate or serum were significantly suppressed by DZQE as well. Moreover, mRNA sequencing data showed that the expressions of inflammation-related genes were elevated in EAP-induced BPH but not in E2/T-induced BPH. ERK1/2-related genes expression has been found in both E2/T and EAP-induced BPH. ERK1/2 is one of the core signal pathways involved in EAP-induced BPH, which was activated in EAP group but inactivated in DZQE group. In vitro, two active components of DZQE Tan IIA and Ba inhibited M2CM-induced BPH-1 cell proliferation, similarly to ERK1/2 inhibitor PD98059 did. Meanwhile, Tan IIA and Ba inhibited M2CM-induced ERK1/2 signal activation in BPH-1 cells. When re-activated the ERK1/2 by its activator C6-Ceramide, the inhibitory effects of Tan IIA and Ba on BPH-1 cell proliferation were blocked.

CONCLUSION

DZQE suppressed inflammation-associated BPH via regulation of ERK1/2 signal by Tan IIA and Ba.

Mixture of Corni Fructus and Schisandrae Fructus improves testosterone-induced benign prostatic hyperplasia through regulating 5α-reductase 2 and androgen receptor

BACKGROUND/OBJECTIVES

Benign prostatic hyperplasia (BPH) characterized by an enlarged prostate gland is common in elderly men. Corni Fructus (CF) and Schisandrae Fructus (SF) are known to have various pharmacological effects, including antioxidant and anti-inflammatory activities. In this study, we evaluated the inhibitory efficacy of CF, SF, and their mixture (MIX) on the development of BPH using an in vivo model of testosterone-induced BPH.

MATERIALS/METHODS

Six-week-old male Sprague-Dawley rats were randomly divided into seven groups. To induce BPH, testosterone propionate (TP) was injected to rats except for those in the control group. Finasteride, saw palmetto (SP), CF, SF, and MIX were orally administered along with TP injection. At the end of treatment, histological changes in the prostate and the level of various biomarkers related to BPH were evaluated.

RESULTS

Our results showed that BPH induced by TP led to prostate weight and histological changes. Treatment with MIX effectively improved TP-induced BPH by reducing prostate index, lumen area, epithelial thickness, and expression of BPH biomarkers such as 5α-reductase type 2, prostate-specific antigen, androgen receptor, and proliferating cell nuclear antigen compared to treatment with CF or SF alone. Moreover, MIX further reduced levels of elevated serum testosterone, dihydrotestosterone, and prostate-specific antigen in BPH compared to the SP, a positive control. BPH was also improved more by MIX than by CF or SF alone.

CONCLUSIONS

Based on the results, MIX is a potential natural therapeutic candidate for BPH by regulating 5α-reductase and AR signaling pathway.

Combination of Ligustri Lucidi Fructus with Ecliptae Herba and their phytoestrogen or phytoandrogen like active pharmaceutical ingredients alleviate oestrogen/testosterone-induced benign prostatic hyperplasia through regulating steroid 5-α-reductase

BACKGROUND

Benign prostatic hyperplasia (BPH) is a urinary system disease with high prevalence among the middle and elder men. In BPH, proliferation of prostate cells and the imbanlance between androgen and estrogen are both important inducers. Previous studies have demonstrated that compounds from Ligustri Lucidi Fructus (LLF) and Ecliptae Herba (EH) are of phytoestrogenic or phytoandrogenic activities. The combination of LLF with EH at the ratio of 1:1 on crude drugs quantity is called Erzhi formula (EZF), which is used for in vivo research of our study.

PURPOSE

This study aimed to investigate potential mechanisms of EZF and its active pharmaceutical ingredients on BPH in vitro and in vivo.

METHODS

Therapeutic effects of EZF was evaluated in E₂/testosterone (1:100) induced BPH rats model. The pathological changes of prostate, concentrations of testosterone, DHT, E₂, PSA in rats' plasma and prostate were detected. The expressions of PCNA, AR, ERα, ERβ, SRD5A1, SRD5A2 were measured in BPH rat prostates and E₂-stimulated human benign prostatic epithelial cells (BPH-1).

RESULTS

EZF treatment significantly attenuated rat prostate enlargement, alleviated BPH pathological features, and decreased the expression of PCNA. The up-regulation of AR, ERα, SRD5A1/2 expressions, and down-regulation of ERβ expression at prostate of rat BPH model were significantly blocked by EZF administration. The expression levels of testosterone, DHT, E₂, PSA were strongly inhibited by EZF treatment. At the cellular level, ligustrosidic acid and echinocystic acid inhibited E₂-induced BPH-1 cell proliferation and PCNA expressions, which were consistent with the results in vivo. And these two ingredients also down-regulated the expressions of AR, ERα, SRD5A1/2 and up-regulated the expression of ERβ in BPH-1 cells.

CONCLUSION

EZF, ligustrosidic acid from LLF and echinocystic acid from EH showed inhibitive effects on BPH via down-regulating prostatic AR, ERα, SRD5A1/2 expressions and up-regulating ERβ expression.

Piperazine-Derived α1D/1A Antagonist 1- Benzyl-N- (3-(4- (2-Methoxyphenyl) Piperazine-1-yl) Propyl) -1H- Indole-2- Carboxamide Induces Apoptosis in Benign Prostatic Hyperplasia Independently of α1-Adrenoceptor Blocking

Previous studies have indicated that α_1D/1A antagonist naftopidil (NAF) suppresses prostate growth by decreasing cell proliferation without affecting apoptosis and prostate volume in benign prostatic hyperplasia (BPH). A NAF-derived α1D/1A antagonist 1- benzyl-N-(3-(4-(2-methoxyphenyl) piperazine-1-yl) propyl)-1H-indole-2- carboxamide (HJZ-12) has been reported from our laboratory, which exhibits high subtype-selectivity to both α_1D- and α_1A- AR (47.9- and 19.1- fold, respectively) with respect to a1B-AR in vitro. However, no further study was conducted. In the present study, a pharmacological evaluation of HJZ-12 in BPH was performed on an estrogen/androgen-induced rat BPH model and human BPH-1 cell line. In vivo, HJZ-12 exhibited better performance than NAF in preventing the progression of rat prostatic hyperplasia by not only decreasing prostate weight and proliferation (similar to NAF) but also, shrinking prostate volume and inducing prostate apoptosis (different from NAF). In vitro, HJZ-12 exhibited significant cell viability inhibition and apoptotic induction in BPH-1 cell line, without presenting cell anti-proliferation properties. Intriguingly, the role of HJZ-12 on cell viability and apoptosis was an α1-independent action. Furthermore, RNA-Seq analysis was applied to screen out six anti-apoptotic genes (Bcl-3, B-lymphoma Mo-MLV insertion region 1 [Bmi-1], ITGA2, FGFR3, RRS1, and SGK1). Amongst them, Bmi-1 was involved in the apoptotic induction of HJZ-12 in BPH-1. Overall, HJZ-12 played a remarkable role in preventing the progression of prostatic hyperplasia through α1-independent apoptotic induction, indicating that it will be a multi-target effective candidate for BPH treatment.

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.

Estrogen regulates the proliferation and inflammatory expression of primary stromal cell in benign prostatic hyperplasia

Background

To investigate the expression of estrogen receptor (ER) in prostate tissues of benign prostatic hyperplasia (BPH) individuals, and the effects of estrogen regulating the proliferation and inflammatory expressions of primary prostate stromal cells in BPH.

Methods

A total of 44 human BPH prostate tissues were collected to explore the expression of ER by immunohistochemistry (IHC). Cell proliferation, mRNA and protein expressions were analyzed in primary prostate stromal cells treated with estrogen or estrogen plus fulvestrant through cell count kit-8 (CCK-8) assay, quantitative real-time polymerase chain reaction (qPCR), IHC and western blot, respectively.

Results

Firstly, ERβ was positive, and ERα was negative in the transition zone of prostate among all the 44 individuals with BPH. Secondly, the effects could be partially inhibited by fulvestrant, of estrogen promoting the proliferation of primary prostate stromal cells cultured in dulbecco’s modified eagle medium (DMEM) supplemented with 2% fetal bovine serum (FBS). Thirdly, estrogen up-regulates the mRNA levels of C-C chemokine receptor type 3 (CCR3), CD40 ligand (CD 40L), C-X-C motif chemokine ligand 9 (CXCL9) and interleukin 10 (IL10), and down-regulates the mRNA levels of C-C chemokine receptor type 4 (CCR4) and interleukin 17C (IL17C). Then, the protein expressions of CCR3, CCR4, CD40L, IL10 and IL17C are positive, and CXCL9 is negative in the third-generation primary prostate stromal cells. Finally, the effects could be partially inhibited by fulvestrant, of estrogen up-regulating the protein levels of CD40L and IL10.

Conclusions

The expressions of ER in human BPH prostate tissues are zone-dependent. Estrogen promoting the proliferation of primary prostate stromal cells cultured in DMEM supplemented with 2% FBS. The expressions of CCR3, CCR4, CD 40L, IL17C, CXCL9 and IL10 are regulated by estrogen in primary prostate stromal cells.

Bakuchiol suppresses oestrogen/testosterone-induced Benign Prostatic Hyperplasia development through up-regulation of epithelial estrogen receptor β and down-regulation of stromal aromatase

Estrogens and androgens play critical roles during benign prostatic hyperplasia (BPH) development. Estrogen receptors (ERs), androgen receptor (AR) and aromatase, the key conversion enzyme of androgen to estrogen, are thought to be the effective targets for BPH treatment. Bakuchiol (Ba)-containing herb Psoralea corylifolia has been long-termed used for BPH patients in traditional Chinese medicine while the role and regulatory mechanism of Ba involved remain unclear. Human prostatic cell lines WPMY-1 and BPH-1 and oestrodial/testosterone-induced BPH rats were used as the in vitro and in vivo models. Ba significantly inhibited the proliferation of WPMY-1 and BPH-1 cells. In E2/T-induced BPH model, Ba treatment also significantly inhibited the enlargement of prostate, decreased PI values, reduced the thickness of periglanular smooth muscle layer, and down-regulated the expressions of PCNA and smooth muscle cell marker α-SMA, all of which were highly induced in BPH rats. Moreover, the basal and PGE2-induced expressions of aromatase were reduced in Ba-stimulated WPMY-1 cells, while the expression of ERβ was highly increased in Ba-stimulated BPH-1 cells, both of which are consistent with the findings in Ba group in vivo. Ba induced ERE activity in BPH-1 cells as E2 did; however, silence of ERβ not ERα, blocked Ba-induced ERE activity while E2 still exhibited the significant ERE activity, indicating the regulation of estrogen signaling by Ba is particularly via ERβ. In conclusion, by down-regulation of stromal aromatase and up-regulation of epithelial ERβ, Ba contributes to the balance of estrogen and androgen signaling and further inhibits BPH development.

Cynomorium songaricum Rupr demonstrates phytoestrogenic or phytoandrogenic like activities that attenuates benign prostatic hyperplasia via regulating steroid 5-α-reductase

ETHNOPHARMACOLOGICAL RELEVANCE

Cynomorium songaricum Rupr. (CS) belongs to the genus of parasitic perennial flowering plants, mostly used in Chinese traditional medicine for benign prostatic hyperplasia (BPH) treatment. BPH is a chronic disease in men that both androgen and estrogen play a crucial role in promoting its development via their receptors. Previously we have showed that compounds from CS have the phytoestrogenic and/or phytoandrogenic activities that may have the potential suppressive effects on BPH, while the mechanism remains unclear.

AIM OF THE STUDY

In this study, we aim to investigate the effect of CS and its derived compounds: luteolin (LUT), gallic acid (GA), protocatechuic acid (PA) and protocatechualdehyde (Pra) on inhibition of rat BPH and proliferation of BPH-1 cell line respectively, and further uncover whether it is related with the phytoestrogenic and / or phytoandrogenic activities.

MATERIALS AND METHODS

Estradiol/testosterone (1:100) was subcutaneous injected to induce BPH in a castrated rat model, and CS was orally administrated for 45 days. Then the weights of the body and prostate were recorded, the pathogenesis changes of prostate were analyzed by Hematoxylin and eosin (H&E) and immunohistochemical (IHC). The levels of 17β-estradiol (E₂), testosterone, and dihydrotestosterone (DHT) from rats' serum were measured by enzyme-linked immunosorbent assay (ELISA). In vitro, human benign prostatic epithelial cell BPH-1 was cultured and treated with or without different CS compounds and DHT or E₂. MTT and CCK-8 assays were performed to detect the regulatory effects on cell proliferation. The expressions of PCNA, AR, ERα, ERβ, and steroid 5-α-reductases (SRD5A1 and SRD5A2) were further analyzed by western blotting upon treatment.

RESULTS

Treatment with CS significantly inhibited rat prostate enlargement, improved the pathological feature and reduced the thickness of smooth muscle layer. The up-regulated AR and ERα expressions and down-regulated ERβ in BPH rat prostate were significantly blocked after CS administration. Moreover, the enhanced values of E₂/testosterone and the level of DHT in serum were also strongly inhibited in CS group compared with those in BPH groups. In cellular level, LUT, GA, PA, or Pra significantly inhibited DHT- or E₂- induced BPH-1 cell proliferation and PCNA expressions. Consistently with the data in vivo, compounds from CS interfered the DHT or E₂-regulated AR, ERα and ERβ expressions in BPH-1 cells as well. Importantly, the dramatic increased SRD5A1 and SRD5A2 expressions were observed in BPH rat prostates and DHT or E₂-stimulated BPH-1 cells. However, treatment with CS in rat or with compounds isolated from CS in BPH-1 cells significantly blocked the induction of SRD5A1 and SRD5A2.

CONCLUSIONS

CS suppressed BPH development through interfering with prostatic AR, ERα/β, and SRD5A1/2 expressions, which provided evidence of CS for BPH treatment.

Testosterone regulates myosin II isoforms expression and functional activity in the rat prostate

BACKGROUND

Benign prostatic hyperplasia (BPH) is mainly caused by increased prostatic smooth muscle (SM) tone and prostatic volume. At the molecular level, SM myosin II (SMM II) and non-muscle myosin II (NMM II) mediate SM tone and cell proliferation while testosterone (T) plays a permissive role in the development of BPH.

AIMS

The novel objective of this study was to elucidate the effects of T on the proliferation and apoptosis of rat prostatic cells and SM contractility as well as related regulatory signaling pathways.

MATERIALS AND METHODS

Briefly, 36 male rats were divided into three groups (sham-operated, surgically castrated, and castrated with T supplementation). In vitro organ bath studies, competitive RT-PCR, Western-blotting analysis, Masson's trichrome staining, and immunofluorescence staining were performed.

RESULTS

Our data showed that castration dramatically increased prostatic SM contractility and SM MHC immunostaining revealed a relatively increased SM cell numbers in the stroma. T deprivation altered prostate SMM II isoform composition with upregulation of SM-B and SM2 but downregulation of LC17a, favoring a faster more phasic-type contraction. Moreover, protein expressions of MLCK, p-MLCP, RhoB, ROCK1, and ROCK2 increased in castrated rats. Meanwhile NMM II heavy chain isoforms A, B, and C (NMMHC-A, B, and C isoforms) were altered by castration which may be linked to decreased cell proliferation and increased apoptosis.

CONCLUSION

Our novel data demonstrated T regulates SMM II and NMM II and their functional activities in rat prostate and T ablation not only decreases prostate size (static component) but also changes the prostatic SM tone (dynamic component).

Estradiol promotes epithelial-to-mesenchymal transition in human benign prostatic epithelial cells

BACKGROUND

Epithelial-to-mesenchymal transition (EMT) is involved in pathogenesis of human benign prostatic hyperplasia (BPH). Estrogenic signaling pathways may stimulate the induction of EMT. However, the details of estradiol (E2) and estrogen receptors (ERs) effects on EMT, as well as E2-induced modulation of benign prostatic epithelial cell phenotype in vitro have not been completely clarified.

METHODS

The effects of E2 on EMT markers and cytokeratins (CKs) expression were evaluated in benign epithelial cell lines BPH-1 and RWPE-1, which were cultured both in two-dimensional (2D) culture and three-dimensional (3D) culture model using hanging drop technique or 3D Matrigel model. ER antagonist, ICI182,780, was used to confirm the regulatory effects of E2 on EMT and phenotypic modulation. In 3D culture, immunohistochemical stainings were performed to detect the specific phenotype of cells that underwent EMT in acinar-like spheroids formed by RWPE-1. To illustrate the exact function of ERs in E2-induced EMT and phenotypic modulation, specific short interfering RNAs (siRNAs), and agonists were used to knockdown or activate individual ERs, respectively.

RESULTS

E2-induced EMT was observed both in 2D and 3D culture, with related regulation of EMT markers expression at both mRNA and protein level. In addition, E2 down-regulated luminal cell type markers CK18 and CK8 and up-regulated basal cell type markers CK5 and CK14. E2 also increased intermediate type markers CK15 and CK17, while it attenuated CK19 in 3D culture. ICI182,780 blocked E2-induced EMT and cell phenotypic switching. In 3D Matrigel culture, Vimentin was co-expressed with ERα and CK17, as well as with SMemb, which is related to cell status switching and proliferation. Knockdown of ERα but not GPR30 inhibited EMT, while ERβ knockdown facilitated EMT process. Knockdown of ERα blocked E2-induced EMT both in RWPE-1 and BPH-1. MRNA expression of EMT markers was stimulated by ERα-specific agonist PPT and inhibited by ERβ-specific agonist DPN.

CONCLUSIONS

Estrogenic effect mediated by ERα can promote EMT. E2 is also an inductive factor of cell phenotypic switching. Cell type modulation is associated with E2-induced EMT in benign prostatic epithelial cells. Taken together the results support a contribution of estrogens to the pathogenesis of BPH in elderly men.

Compounds from Cynomorium songaricum with Estrogenic and Androgenic Activities Suppress the Oestrogen/Androgen-Induced BPH Process

Objective

To investigate the phytoestrogenic and phytoandrogenic activities of compounds isolated from CS and uncover the role of CS in prevention of oestrogen/androgen-induced BPH.

Methods

Cells were treated with CS compounds, and immunofluorescence assay was performed to detect the nuclear translocation of ERα or AR in MCF-7 or LNCaP cells; luciferase reporter assay was performed to detect ERs or AR transcriptional activity in HeLa or AD293 cells; MTT assay was performed to detect the cell proliferation of MCF-7 or LNCaP cells. Oestrogen/androgen-induced BPH model was established in rat and the anti-BPH, anti-estrogenic, and anti-androgenic activities of CS in vivo were further investigated.

Results

The nuclear translocation of ERα was stimulated by nine CS compounds, three of which also stimulated AR translocation. The transcriptional activities of ERα and ERβ were induced by five compounds, within which only ECG induced AR transcriptional activity as well. Besides, ECG stimulated the proliferation of both MCF-7 cells and LNCaP cells. CS extract suppressed oestrogen/androgen-induced BPH progress in vivo by downregulation of E2 and T level in serum and alteration of the expressions of ERα, ERβ, and AR in the prostate.

Conclusion

Our data demonstrates that compounds from CS exhibit phytoestrogenic and phytoandrogenic activities, which may contribute to inhibiting the oestrogen/androgen-induced BPH development.

Pharmaceutical evaluation of naftopidil enantiomers: Rat functional assays in vitro and estrogen/androgen induced rat benign prostatic hyperplasia model in vivo

Naftopidil (NAF) is a α_1D/1A adrenoceptor selective drug used for the treatment of both benign prostatic hyperplasia and lower urinary tract symptoms (BPH/LUTS). However, NAF is used as a racemate in clinic. To compare the differences and similarities among two enantiomers and racemate, pharmacological activities were evaluated through rat functional assays in vitro and estrogen/androgen (E/T) induced rat BPH model in vivo. NAF and the two enantiomers showed similar blocking activity on α₁ receptor. S-NAF exhibited more α_1D/1A adrenoceptor subtype selectivity than R-NAF and the racemate. The selectivity ratios pA₂ (α_1D)/pA₂ (α_1B) and pA₂ (α_1A)/pA₂ (α_1B) were 40.7- and 16.2-fold, respectively. NAF and its enantiomers effectively prevented the development of rat prostatic hyperplasia via suppressing the increase of the prostatic wet weight, visually. The quantitative analysis of the relative acinus volume, relative stroma volume, relative epithelial volume, epithelial height and expression of proliferating cell nuclear antigen (PCNA) and α-smooth muscle actin (α-SMA) were carried out. S-NAF showed an advantage on the effect of inhibiting prostate wet weight and stroma volume over R-NAF and racemate NAF (P<0.05). Nevertheless, no other significant difference was observed between these two enantiomers. In conclusion, both R-NAF and S-NAF not only relax prostate muscle but also inhibit the prostate growth, thus relieve BPH.

GPR30 Promotes Prostate Stromal Cell Activation via Suppression of ERα Expression and Its Downstream Signaling Pathway

Cancer-associated fibroblasts (CAFs) play a vital role in malignant transformation and progression of prostate cancer (PCa), and accumulating evidence suggests an enhancing effect of estrogens on PCa. The present study aimed to investigate the possible origin of prostate CAFs and the effects of estrogen receptors, G protein-coupled receptor 30 (GPR30) and estrogen receptor (ER)-α, on stromal cell activation. High expression of fibroblast activation protein (FAP), CD44, and nonmuscle myosin heavy chain B (SMemb) accompanied by low expression of smooth muscle differentiation markers was found in the stromal cells of PCa tissues and in cultured human prostate CAFs. Additionally, SMemb expression, which is coupled to cell phenotype switching and proliferation, was coexpressed with FAP, a marker of activated stromal cells, and with the stem cell marker CD44 in the stromal cells of PCa tissue. Prostate CAFs showed high GPR30 and low ERα expression. Moreover, GPR30 was coexpressed with FAP, CD44, and SMemb. Furthermore, the study demonstrated that the overexpression of GPR30 or the knockdown of ERα in prostate stromal cells induced the up-regulation of FAP, CD44, Smemb, and the down-regulation of smooth muscle markers. The conditioned medium from these cells promoted the proliferation and migration of LNCaP and PC3 PCa cells. GPR30 knockdown or ERα overexpression showed opposite effects. Finally, we present a novel mechanism whereby GPR30 limits ERα expression via inhibition of the cAMP/protein kinase A signaling pathway. These results suggest that stem-like cells within the stroma are a possible source of prostate CAFs and that the negative regulation of ERα expression by GPR30 is centrally involved in prostate stromal cell activation.

Custom 4-Plex DiLeu Isobaric Labels Enable Relative Quantification of Urinary Proteins in Men with Lower Urinary Tract Symptoms (LUTS)

The relative quantification of proteins using liquid chromatography mass spectrometry (LC-MS) has allowed researchers to compile lists of potential disease markers. These complex quantitative workflows often include isobaric labeling of enzymatically-produced peptides to analyze their relative abundances across multiple samples in a single LC-MS run. Recent efforts by our lab have provided scientists with cost-effective alternatives to expensive commercial labels. Although the quantitative performance of these dimethyl leucine (DiLeu) labels has been reported using known ratios of complex protein and peptide standards, their potential in large-scale proteomics studies using a clinically relevant system has never been investigated. Our work rectifies this oversight by implementing 4-plex DiLeu to quantify proteins in the urine of aging human males who suffer from lower urinary tract symptoms (LUTS). Protein abundances in 25 LUTS and 15 control patients were compared, revealing that of the 836 proteins quantified, 50 were found to be differentially expressed (>20% change) and statistically significant (p-value <0.05). Gene ontology (GO) analysis of the differentiated proteins showed that many were involved in inflammatory responses and implicated in fibrosis. While confirmation of individual protein abundance changes would be required to verify protein expression, this study represents the first report using the custom isobaric label, 4-plex DiLeu, to quantify protein abundances in a clinically relevant system.

The therapeutic effects of docosahexaenoic acid on oestrogen/androgen-induced benign prostatic hyperplasia in rats

Benign prostatic hyperplasia (BPH) is one of the major disorders of the urinary system in elderly men. Docosahexaenoic acid (DHA) is the main component of n-3 polyunsaturated fatty acids (n-3 PUFAs) and has nerve protective, anti-inflammatory and tumour-growth inhibitory effects. Here, the therapeutic potential of DHA in treating BPH was investigated. Seal oil effectively prevented the development of prostatic hyperplasia induced by oestradiol/testosterone in a rat model by suppressing the increase of the prostatic index (PI), reducing the thickness of the peri-glandular smooth muscle layer, inhibiting the proliferation of both prostate epithelial and stromal cells, and downregulating the expression of androgen receptor (AR) and oestrogen receptor α (ERα). An in vitro study showed that DHA inhibited the growth of the human prostate stromal cell line WPMY-1 and the epithelial cell line RWPE-1 in a dose- and time-dependent manner. In both cell lines, the DHA arrested the cell cycle in the G2/M phase. In addition, DHA also reduced the expression of ERα and AR in the WPMY-1 and RWPE-1 cells. These results indicate that DHA inhibits the multiplication of prostate stromal and epithelial cells through a mechanism that may involve cell cycle arrest and the downregulation of ERα and AR expression.

The prevention and treatment effects of tanshinone IIA on oestrogen/androgen-induced benign prostatic hyperplasia in rats

Benign prostatic hyperplasia (BPH) is one of the major diseases of the urinary system in elderly men. Tanshinone IIA (Tan IIA) is the active ingredient extracted from the traditional Chinese medicine Salvia, and it has effects of anti-oxidation, anti-inflammation, vascular smooth muscle relaxation and tumour growth inhibition. The present study aimed to investigate the therapeutic potential of Tan IIA in the prevention and treatment of BPH. In a rat model of oestradiol/testosterone-induced BPH, Tan IIA inhibited the increase in the thickness of the peri-glandular smooth muscle layer, suppressed the expression of proliferating cell nuclear antigen (PCNA) in both prostate epithelial cells and stromal cells, downregulated the expression of androgen receptor (AR), oestrogen receptor α (ERα), cyclin B1 (CCNB1) and cyclin D1 (CCND1), and effectively prevented the development of the disorder. In vitro, Tan IIA inhibited the proliferation of human prostate stromal cell line WPMY-1 and epithelial cell line RWPE-1 in a dose- and time-dependent manner. In WPMY-1 cells, Tan IIA treatment arrested the cell cycle at the G2/M phase and downregulated the expression of CCNB1. However, in RWPE-1 cells, Tan IIA treatment arrested cell cycle at the G0/G1 phase and reduced the expression of CCND1. Tan IIA also reduced the expression of ERα and AR in WPMY-1 and RWPE-1 cells. These results suggest that Tan IIA can inhibit the growth of prostate stromal and epithelial cells both in vivo and in vitro by a mechanism that may involve arresting the cell cycle and downregulating ERα and AR expression.

Epithelial-to-mesenchymal transition and estrogen receptor α mediated epithelial dedifferentiation mark the development of benign prostatic hyperplasia

BACKGROUND

Epithelial-to-mesenchymal transition (EMT) has been reported involved in the pathogenesis of fibrotic disorders and associated with stemness characteristics. Recent studies demonstrated that human benign prostatic hyperplasia (BPH) development involves accumulation of mesenchymal-like cells derived from the prostatic epithelium. However, the inductive factors of EMT in the adult prostate and the cause-and-effect relationship between EMT and stemness characteristics are not yet resolved.

METHODS

EMT expression patterns were immunohistochemically identified in the human epithelia of normal/BPH prostate tissue and in a rat BPH model induced by estrogen/androgen (E2/T, ratio 1:100) alone or in the presence of the ER antagonist raloxifene. Gene expression profiles were analyzed in micro-dissected prostatic epithelia of rat stimulated by E2/T for 3 days.

RESULTS

Two main morphological features both accompanied with EMT were observed in the epithelia of human BPH. Luminal cells undergoing EMT dedifferentiated from a cytokeratin (CK) CK18(+) /CK8(+) /CK19(+) to a CK18(-) /CK8(+) /CK19(-) phenotype and CK14 expression increased in basal epithelial cells. ERα expression was closely related to these dedifferentiated cells and the expression of EMT markers. A similar pattern of EMT events was observed in the E2/T induced rat model of BPH in comparison to the prostates of untreated rats, which could be prevented by raloxifene.

CONCLUSIONS

Epithelial and mesenchymal phenotype switching is an important mechanism in the etiology of BPH. ERα mediated enhanced estrogenic effect is a crucial inductive factor of epithelial dedifferentiation giving rise to activation of an EMT program in prostate epithelium.

Selective estrogen receptor modulators for BPH: new factors on the ground

As the current management of BPH/lower urinary tract symptoms by traditionally involved pharmacological agents such as 5alpha-reductase inhibitors and α1-adrenoceptor antagonists is suboptimal, there is definite need of new therapeutic strategies. There is ample evidence in literature that suggests the role of estrogens in BPH development and management through the different tissue and cell-specific receptors. This article reviews the beneficial actions of selective estrogen receptor modulator (SERM) and ERβ-selective ligands, which have been demonstrated through in vitro studies using human prostate cell lines and in vivo animal studies. SERMs have anti-proliferative, anti-inflammatory and pro-apoptotic mechanisms in BPH, and also act by inhibiting various growth factors, and thus represent a unique and novel approach in BPH management directed at estrogen receptors or estrogen metabolism.

Fibrosis-related gene expression in the prostate is modulated by doxazosin treatment

AIMS

To gain new insights into the molecular mechanisms of action of doxazosin, we investigated the prostatic stroma ultrastructure and the expression of genes involved with fibrosis, such as collagen type I and III (COL1A1 and COL3A1, respectively) and TGF-beta 1, in the rat ventral prostate.

MAIN METHODS

Adult Wistar rats were treated with doxazosin (25mg/kg/day), and the ventral prostates were excised at 7 and 30days after treatment. Untreated rats were controls. Ventral prostates were subjected to ultrastructural, immunohistochemical, biochemical and molecular analyses.

KEY FINDINGS

Doxazosin-treated prostates showed thickened bundles of collagen fibrils, activated fibroblasts, enlarged neurotransmitter vesicles and increased tissue immunostaining for collagen type I and type III when compared to untreated prostates. After 7 and 30days of doxazosin treatment mRNA expression of COL1A1 and COL3A1 was significantly increased and reduced, respectively, compared to the control group. TGF-beta 1 mRNA and protein levels were increased after 7days of doxazosin treatment, whereas only mRNA levels remained increased after 30days of treatment.

SIGNIFICANCE

Our data suggest that relaxation of smooth muscle cells by alpha-blockers interferes with the mechanical dynamics of the prostatic stroma extracellular matrix components, generating a pro-fibrotic effect probably via the TGF-beta 1 signaling pathway. Long term treatment with doxazosin may also lead to a reduced turnover of extracellular matrix components. Our results add to a better understanding of the molecular mechanisms behind the effects of alpha-blockade on prostatic histoarchitecture and the response to treatment for benign prostatic hyperplasia.

Influence of immune inflammation on androgen receptor expression in benign prostatic hyperplasia tissue

This study was designed to investigate the association between immune inflammation and androgen receptor (AR) expression in benign prostatic hyperplasia (BPH). We retrospectively analyzed 105 prostatectomy specimens. An immune inflammation score for each specimen was defined by combining three immunohistochemical markers (CD4, CD8 and CD20). The immunohistochemical markers were CD4 and CD8 for T lymphocytes, CD20 for B lymphocytes and AR antibody for the AR in BPH samples. Rates of CD4, CD8, CD20 and AR expression in BPH were 20 (19.0%), 21 (20.0%), 101 (96.2%) and 48 (45.7%), respectively. Total prostate volume (TPV) was higher in the immune inflammation group than in the non-immune inflammation group (62.7 ml vs. 49.2 ml, t=2.482, P<0.05). Patients in the immune inflammation group had a higher serum prostate-specific antigen (PSA) than those in the non-inflammation group (7.5 ng ml(-1 )vs. 5.4 ng ml(-1), t=2.771, P<0.05). Specifically, the immune inflammation group showed a higher rate of AR expression than the non-inflammation group (56.1% vs. 28.2%, χ(2)=7.665, P<0.05). Our study revealed a strong association between immune inflammation and TPV, serum PSA and AR expression in BPH tissue. Prostate hyperplasia caused by an immune inflammatory process may contribute to BPH progression over time. Therefore, the inflammatory response involved in BPH may be a prime therapeutic target.

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.

Animal models for benign prostatic hyperplasia

Although the etiology of benign prostatic hyperplasia (BPH) is unknown, various animal models have been used for several decades to identify potential therapeutic approaches. These models can be divided into those measuring smooth muscle tone and those measuring cellular proliferation. Animal models have played an important role in the development of the two drug classes currently approved for the treatment of BPH: the α-adrenoceptor antagonists and the steroid 5-α-reductase inhibitors. However, models measuring prostatic tone have not been particularly useful in the identification of new α-adrenoceptor antagonists having advantages over currently available drugs, and it is not certain that reduction of prostatic smooth muscle tone is responsible for the relief of BPH symptoms. A further limitation with BPH models is that prostatic hyperplasia similar to the human condition does not occur spontaneously or cannot be induced in any suitable animal species. The identification of a more useful BPH model is focused on cellular mechanisms of prostatic growth, looking similarities between humans and experimental animals.

Antagonism of estrogen-mediated cell proliferation by raloxifene in prevention of ageing-related prostatic hyperplasia

Estrogen has important roles in the initiation and development of benign prostatic hyperplasia (BPH). Regulators of the estrogen receptor (ER) are tissue- and cell-specific. We evaluated the effect of estrogen antagonist, raloxifene (Ral), on the prevention and treatment of BPH by investigating its effect on the proliferation of two different prostate cell lines: a stromal cell line, WPMY-1, and a benign prostatic hyperplasia epithelial cell line, BPH-1. We additionally evaluated its effect on prostatic hyperplasia induced by estrogen and androgen in a rat model. The effect of Ral on the prevention of prostatic hyperplasia was analyzed by haematoxylin and eosin staining and quantitative immunohistochemistry (IHC) for proliferating cell nuclear antigen and alpha-smooth muscle actin. In vitro and in vivo, tamoxifen (Tam), another anti-estrogen drug, and finasteride (Fin), a drug for the clinical treatment of BPH, served as efficacy controls. The in vitro data showed that neither Ral nor Tam alone affected the proliferation of WPMY-1 and BPH-1, but both antagonized the effect of oestradiol in promoting the proliferation of the two cells. Results from the IHC staining of the rat prostates indicated that, similar to Tam and Fin, Ral inhibited the proliferation of stromal cells in vivo. Interestingly, in contrast to Tam, both Ral and Fin inhibited the proliferation of epithelial cells. Furthermore, Ral treatment much strongly decreased the number of prostatic acini and the surrounding layers of smooth muscle cells than Fin (P < 0.05). Our data showed for the first time that Ral may have a role in the response of the rat prostate to selective ER modulators.