Upregulation of Phosphodiesterase type 5 in the Hyperplastic Prostate

Measurement of PDE5 concentration in human serum: proof-of-concept and validation of methodology in control and prostate cancer patients

PURPOSE

We aimed to investigate if the type 5 phosphodiesterase (PDE5), an enzyme with cardinal biological functions in sexual and cardiovascular health, can be detected and quantited in human serum.

METHODS

Blood samples were collected from control male and female subjects. PDE5 levels were measured by a specific ELISA kit. ROC curves weighted for age and serum levels of PSA (male subjects), or age (female subjects) were used to identify the predictive ability in the detection of PCa. Sensitivity, specificity, PPV and NPV values were determined for cut-off value determined during ROC curve analysis.

RESULTS

41 control male subjects, 18 control female subjects, and 55 consecutive subjects, of which 25 were affected by benign prostatic hypertrophy (BPH) and 30 with histologically confirmed prostate cancer (PCa), were studied. PDE5 serum levels were detectable in all subjects (range: 5 to 65 ng/ml). Analysis by MANCOVA identified a significant difference in serum PDE5 between control subjects or hyperplasia patients and PCa patients. Marginal means of serum PDE5 concentrations showed a significant difference (p < 0.001). The ROC curve demonstrated that PDE5 serum levels can predict men with or without PCa, with 0.806 AUC value (p < 0.0001). Using a 12.705 ng/ml PDE5 serum cut-off yielded sensitivity, specificity, PPV, and NPV of 83.3%, 77.27%, 62.5%, and 91.1% in detecting men with histologically proven PCa, respectively.

CONCLUSIONS

We demonstrated, for the first time, that PDE5 levels can be detected in human sera and that PCa patients have significantly higher PDE5 concentration compared to BPH patients or male and female controls. While serum PDE5 level measurement may open new research avenues, the clinical relevance of PDE5 levels in PCa patients deserves further investigation.

Activation of the cGMP/PKG/ERK signaling pathway associated with PDE5Is inhibits fibroblast activation by downregulating autophagy in early progressive benign prostatic hyperplasia

PURPOSE

Benign prostatic hyperplasia (BPH) is one of the most prevalent diseases affecting aging males. However, approximately, 8% of the BPH patients under 50-year-old experience remarkably early progression, for reasons that remain elusive. Among the various factors implicated in promoting BPH advancement, the activation of fibroblasts and autophagy hold particular importance. Our research endeavors to explore the mechanisms behind the accelerated progression in these patients.

METHODS

Immunohistochemistry and immunofluorescence were performed to detect the expression levels of LC3, p62, PDE5, and α-SMA in diverse BPH tissues and prostate stromal cells. The autophagy activator rapamycin, the autophagy suppressor chloroquine, and siRNA transfection were used to identify the impact of autophagy on fibroblast activation.

RESULTS

Prostatic stromal fibroblasts in early progressive BPH tissues displayed activation of autophagy with an upregulation of LC3 and a concurrent downregulation of p62. After starvation or rapamycin treatment to a heightened level of autophagy, fibroblasts exhibited activation. Conversely, chloroquine treatment and ATG-7-knockdown effectively suppressed the level of autophagy and fibroblast activation. High expression of PDE5 was found in early progressive BPH stromal cells. The administration of PDE5 inhibitors (PDE5Is) hindered fibroblast activation through suppressing autophagy by inhibiting the ERK signaling pathway.

CONCLUSION

Our findings suggest that autophagy plays a pivotal role in promoting BPH progression through fibroblast activation, while PDE5Is effectively suppress autophagy and fibroblast activation via the ERK signaling pathway. Nevertheless, further investigations are warranted to comprehensively elucidate the role of autophagy in BPH progression.

Alteration of the Expression and Functional Activities of Myosin II Isoforms in Enlarged Hyperplastic Prostates

INTRODUCTION

Benign prostatic hyperplasia (BPH) is a common pathologic process in aging men, and the contraction of the prostatic smooth muscles (SMs) in the stroma plays a vital role in this pathogenesis, leading to lower urinary tract symptoms (LUTSs). The isoforms of both the SM myosin (SMM) and non-muscle myosin (NMM) are associated with the contraction type of the prostatic SMs, but the mechanism has not been fully elucidated.

METHODS

We collected prostate tissues from 30 BPH patients receiving surgical treatments, and normal human prostate samples were obtained from 12 brain-dead men. A testosterone-induced (T-induced) rat model was built, and the epithelial hyperplastic prostates were harvested. Competitive RT-PCR was used to detect the expression of SMM isoforms. We investigated the contractility of human prostate strips in vitro in an organ bath.

RESULTS

The results regarding the comparisons of SMM isoforms varied between rat models and human samples. In comparison with T-induced rats and controls, competitive RT-PCR failed to show any statistically significant difference regarding the compositions of SMM isoforms. For human prostates samples, BPH patients expressed more SM-1 isoforms (66.8% vs. 60.0%, p < 0.001) and myosin light chain-17b (MLC17b) (35.9% vs. 28.5%, p < 0.05) when compared to young donors. There was a significant decrease in prostate myosin heavy chain (MHC) expression in BPH patients, with a 66.4% decrease in MHC at the mRNA level and a 51.2% decrease at the protein level. The upregulated expression of non-muscle myosin heavy chain-B (NMMHC-B) was 1.6-fold at the mRNA level and 2.1-fold at the protein level. The organ bath study showed that isolated prostate strips from BPH patients produced slower tonic contraction compared to normal humans.

CONCLUSION

In this study, we claim that in the enlarged prostates of patients undergoing surgeries, MHC expression significantly decreased compared to normal tissues, with elevated levels of SM-1, MLC17b, and NMMHC-B isoforms. Modifications in SMM and NMM might play a role in the tonic contractile properties of prostatic SMs and the development of LUTS/BPH. Understanding this mechanism might provide insights into the origins of LUTS/BPH and facilitate the identification of novel therapeutic targets.

Simvastatin Improves Benign Prostatic Hyperplasia: Role of Peroxisome-Proliferator-Activated Receptor-γ and Classic WNT/β-Catenin Pathway

Benign prostatic hyperplasia (BPH) is a common disease in elderly men with an uncertain etiology and mechanistic basis. Metabolic syndrome (MetS) is also a very common illness and is closely related to BPH. Simvastatin (SV) is one of the widely used statins for MetS. Peroxisome-proliferator-activated receptor gamma (PPARγ), crosstalking with the WNT/β-catenin pathway, plays important roles in MetS. Our current study aimed to examine SV-PPARγ-WNT/β-catenin signaling in the development of BPH. Human prostate tissues and cell lines plus a BPH rat model were utilized. Immunohistochemical, immunofluorescence, hematoxylin and eosin (H&E) and Masson's trichrome staining, construction of a tissue microarray (TMA), ELISA, CCK-8 assay, qRT-PCR, flow cytometry, and Western blotting were also performed. PPARγ was expressed in both prostate stroma and epithelial compartments and downregulated in BPH tissues. Furthermore, SV dose-dependently triggered cell apoptosis and cell cycle arrest at the G0/G1 phase and attenuated tissue fibrosis and the epithelial-mesenchymal transition (EMT) process both in vitro and in vivo. SV also upregulated the PPARγ pathway, whose antagonist could reverse SV produced in the aforementioned biological process. Additionally, crosstalk between PPARγ and WNT/β-catenin signaling was demonstrated. Finally, correlation analysis with our TMA containing 104 BPH specimens showed that PPARγ was negatively related with prostate volume (PV) and free prostate-specific antigen (fPSA) and positively correlated with maximum urinary flow rate (Qmax). WNT-1 and β-catenin were positively related with International Prostate Symptom Score (IPSS) and nocturia, respectively. Our novel data demonstrate that SV could modulate cell proliferation, apoptosis, tissue fibrosis, and the EMT process in the prostate through crosstalk between PPARγ and WNT/β-catenin pathways.

Beyond Erectile Dysfunction: cGMP-Specific Phosphodiesterase 5 Inhibitors for Other Clinical Disorders

Cyclic guanosine monophosphate (cGMP), an important intracellular second messenger, mediates cellular functional responses in all vital organs. Phosphodiesterase 5 (PDE5) is one of the 11 members of the cyclic nucleotide phosphodiesterase (PDE) family that specifically targets cGMP generated by nitric oxide-driven activation of the soluble guanylyl cyclase. PDE5 inhibitors, including sildenafil and tadalafil, are widely used for the treatment of erectile dysfunction, pulmonary arterial hypertension, and certain urological disorders. Preclinical studies have shown promising effects of PDE5 inhibitors in the treatment of myocardial infarction, cardiac hypertrophy, heart failure, cancer and anticancer-drug-associated cardiotoxicity, diabetes, Duchenne muscular dystrophy, Alzheimer's disease, and other aging-related conditions. Many clinical trials with PDE5 inhibitors have focused on the potential cardiovascular, anticancer, and neurological benefits. In this review, we provide an overview of the current state of knowledge on PDE5 inhibitors and their potential therapeutic indications for various clinical disorders beyond erectile dysfunction.

Tadalafil and Steroid Hormones Interactions in Adipose, Bone and Prostate Tissues: Focus on Translational Perspectives

Tadalafil is a selective phosphodiesterase type-5 (PDE5) inhibitor that is approved for the treatment of men with erectile dysfunction (ED) and/or benign prostate hyperplasia (BPH) -associated symptoms. Besides its classical actions on PDE5 within the genitourinary tract, where the specific enzyme expression is maximal, it may exert different systemic effects. This is mainly due to the pleiotropic distribution of PDE5 enzyme throughout the human (and animal) body, where it can exert protective effects in different clinical conditions. Recently, it has been demonstrated that tadalafil may display novel actions on androgen receptor (AR) expression and activity and cytochrome P19a1 (Cyp19a1) and estrogen receptor β (ERβ) expression in different in vitro systems, such as adipose, bone and prostate cancer cells, where it can act as a selective modulator of steroid hormone production. This may determine novel potential mechanism(s) of control in pathophysiologic pathways. In this review, we summarize basic research and translational results applicable to the use of tadalafil in the treatment of obesity, bone loss and prostate cancer.

Benign prostatic hyperplasia/obstruction ameliorated using a soluble guanylate cyclase activator

Benign prostatic hyperplasia (BPH) is a feature of ageing males. Up to half demonstrate bladder outlet obstruction (BOO) with associated lower urinary tract symptoms (LUTS) including bladder overactivity. Current therapies to reduce obstruction, such as α1-adrenoceptor antagonists and 5α-reductase inhibitors, are not effective in all patients. The phosphodiesterase-5 inhibitor (PDE5I) tadalafil is also approved to treat BPH and LUTS, suggesting a role for nitric oxide (NO• ), soluble guanylate cyclase (sGC), and cGMP signalling pathways. However, PDE5I refractoriness can develop for reasons including nitrergic nerve damage and decreased NO• production, or inflammation-related oxidation of the sGC haem group, normally maintained in a reduced state by the cofactor cytochrome-b5-reductase 3 (CYB5R3). sGC activators, such as cinaciguat (BAY 58-2667), have been developed to enhance sGC activity in the absence of NO• or when sGC is oxidised. Accordingly, their effects on the prostate and LUT function of aged mice were evaluated. Aged mice (≥24 months) demonstrated a functional BPH/BOO phenotype, compared with adult animals (2-12 months), with low, delayed voiding responses and elevated intravesical pressures as measured by telemetric cystometry. This was consistent with outflow tract histological and molecular data that showed urethral constriction, increased prostate weight, greater collagen deposition, and cellular hyperplasia. All changes in aged animals were attenuated by daily oral treatment with cinaciguat for 2 weeks, without effect on serum testosterone levels. Cinaciguat had only transient (1 h) cardiovascular effects with oral gavage, suggesting a positive safety profile. The benefit of cinaciguat was suggested by its reversal of an overactive cystometric profile in CYB5R3 smooth muscle knockout mice that mirrors a profile of oxidative dysfunction where PDE5I may not be effective. Thus, the aged male mouse is a suitable model for BPH-induced BOO and cinaciguat has a demonstrated ability to reduce prostate-induced obstruction and consequent effects on bladder function. © 2021 The Pathological Society of Great Britain and Ireland.

Upregulated bone morphogenetic protein 5 enhances proliferation and epithelial-mesenchymal transition process in benign prostatic hyperplasia via BMP/Smad signaling pathway

BACKGROUND

Benign prostatic hyperplasia (BPH) is one of the most common illnesses in aging men. Recent studies found that bone morphogenetic protein 5 (BMP5) is upregulated in BPH tissues, however, the role of BMP5 in the development of BPH has not been examined. The current study aims to elucidate the potential roles of BMP5 and related signaling pathways in BPH.

METHODS

Human prostate cell lines (BPH-1, WPMY-1) and human/rat hyperplastic prostate tissues were utilized. Western blot, quantitative real-time polymerase chain reaction, immunofluorescent staining, and immunohistochemical staining were performed. BMP5-silenced and -overexpressed cell models were generated and then cell cycle progression, apoptosis, and proliferation were determined. The epithelial-mesenchymal transition (EMT) was also quantitated. And rescue experiments by BMP/Smad signaling pathway agonist or antagonist were accomplished. Moreover, BPH-related tissue microarray analysis was performed and associations between clinical parameters and expression of BMP5 were analyzed.

RESULTS

Our study demonstrated that BMP5 was upregulated in human and rat hyperplastic tissues and localized both in the epithelial and stromal compartments of the prostate tissues. E-cadherin was downregulated in hyperplastic tissues, while N-cadherin and vimentin were upregulated. Overexpression of BMP5 enhanced cell proliferation and the EMT process via phosphorylation of Smad1/5/8, while knockdown of BMP5 induced cell cycle arrest at G0/G1 phase and blocked the EMT process. Moreover, a BMP/Smad signaling pathway agonist and antagonist reversed the effects of BMP5 silencing and overexpression, respectively. In addition, BMP5 expression positively correlated with prostate volume and total prostate-specific antigen.

CONCLUSION

Our novel data suggest that BMP5 modulated cell proliferation and the EMT process through the BMP/Smad signaling pathway which could contribute to the development of BPH. However, further studies are required to determine the exact mechanism. Our study also indicated that BMP/Smad signaling may be rediscovered as a promising new therapeutic target for the treatment of BPH.

Smoothened inhibition leads to decreased cell proliferation and suppressed tissue fibrosis in the development of benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is a common disease in aging males. It has been proven that the Hedgehog (HH) is implied as an effective and fundamental regulatory growth factor signal for organogenesis, homeostasis, and regeneration. Smoothened (SMO), as the major control point of HH signals, activates aberrantly in most human solid tumors. However, the specific function of SMO and its downstream glioma-associated oncogene (GLI) family in BPH has not been well understood. Here, we first revealed that the SMO cascade was upregulated in BPH tissues and was localized in both the stromal and the epithelium compartments of human prostate tissues. Cyclopamine, as a specific SMO inhibitor, was incubated with BPH-1 and WPMY-1, and intraperitoneally injected into a BPH rat model established by castration with testosterone supplementation. SMO inhibition could induce cell apoptosis, cell cycle arrest at the G0/G1 phase, and a reduction of tissue fibrosis markers, both in vitro and in vivo. Finally, a tissue microarray, containing 104 BPH specimens, was constructed to analyze the correlations between the expression of SMO cascade and clinical parameters. The GLI2 was correlated positively with nocturia and negatively with fPSA. The GLI3 was in a positive relationship with International Prostate Symptom Score and nocturia. In conclusion, our study suggested that SMO cascade could play important roles in the development of BPH and it might be rediscovered as a promising therapeutic target for BPH.

Phosphodiesterase Type-5 Inhibitor Tadalafil Modulates Steroid Hormones Signaling in a Prostate Cancer Cell Line

Background: The androgen receptor (AR) plays a key role in normal prostate homeostasis and in prostate cancer (PCa) development, while the role of aromatase (Cyp19a1) is still unclear. We evaluated the effects of a treatment with Tadalafil (TAD) on both these proteins. Methods: Androgen-sensitive human PCa cell line (LnCAP) was incubated with/without TAD (10⁻⁶ M) and bicalutamide (BCT) (10⁻⁴ M) to evaluate a potential modulation on cell proliferation, protein and mRNA expression of Cyp19a, AR and estrogen receptor-β (ERβ), respectively. Results: TAD increased early AR nuclear translocation (p < 0.05, after 15 min of exposure), and increased AR transcriptional activity (p < 0.05) and protein expression (p < 0.05) after 24 h. Moreover, after 24 h this treatment upregulated Cyp19a1 and ERβ mRNA (p < 0.05 and p < 0.005 respectively) and led to an increase in protein expression of both after 48 h (p < 0.05). Interestingly, TAD counteracted Cyp19a1 stimulation induced by BCT (p < 0.05) but did not alter the effect induced by BCT on the AR protein expression. Conclusion: We demonstrate for the first time that TAD can significantly modulate AR expression and activity, Cyp19a1 and ERβ expression in PCa cells, suggesting a specific effect of these proteins. In addition, TAD potentiates the antiproliferative activity of BCT, opening a new clinical scenario in the treatment of PCa.

Defining the Efficacy and Safety of Phosphodiesterase Type 5 Inhibitors with Tamsulosin for the Treatment of Lower Urinary Tract Symptoms Secondary to Benign Prostatic Hyperplasia with or without Erectile Dysfunction: A Network Meta-Analysis

Purpose

The purpose of this study was to compare the relative safety and efficacy of different types of phosphodiesterase type 5 inhibitors (PDE5-Is) with tamsulosin for the treatment of lower urinary tract symptoms (LUTS) secondary to benign prostate hyperplasia (BPH) (BPH-LUTS) with or without erectile dysfunction (ED).

Methods

We use the Stata version 13.0 to conduct the network meta-analysis (NMA) with a random effects model of the Bayesian framework. The International Prostate Symptom Score (IPSS), Maximum Urinary Flow Fate (Q_max), International Index of Erectile Function (IIEF), and their credible intervals (CI) were used to compare the efficacy and safety of every medical intervention, including sildenafil plus tamsulosin, tadalafil plus tamsulosin, and vardenafil plus tamsulosin.

Results

Seven RCTs including 531 participants with seven interventions were analyzed. The results of NMA SUCRA showed that compared with different doses or types of PDE5-Is combined with tamsulosin (0.4 mg qd), the sildenafil (25 mg qd) combined with tamsulosin (0.4 mg qd) group had the greatest probabilities of being the best in the achievement of improving IIEF. The sildenafil (25 mg 4 days per week) combined with tamsulosin (0.4 mg qd) group had the greatest probabilities of being the best in the achievement of improving Q_max, whereas sildenafil (25 mg qd) combined with tamsulosin (0.4 mg qd) ranked the best for the safety outcomes.

Conclusions

This meta-analysis indicates that sildenafil combined with tamsulosin is the best effective and tolerated treatment option for BPH-LUTS with or without ED. Further RCTs are strongly required to provide more direct evidence.

Higher expression of phosphodiesterase type 5 in the anterior fibromuscular stroma of the human prostate

PURPOSE

To examine phosphodiesterase type 5 (PDE5) expression in the anterior fibromuscular stroma (AFMS) of the prostate. Although PDE5 expression was identified in the human prostate, differences in PDE5 expression in intra-prostatic regions are unknown. The AFMS in the prostate has peculiar innervations that could contribute to voiding function. Here, we examined regional differences in PDE5 expression in the prostate with special reference to the AFMS.

METHODS

A total 18 human prostate and bladder specimens were obtained. Tissue specimens were processed by hematoxylin-eosin (H&E) staining and immunohistochemistry for PDE5. Immunoreactivity with PDE5 was evaluated using computer-assisted image analysis in the following regions: the AFMS, bladder neck, stromal hyperplasia in the transition zone, glandular hyperplasia in the transition zone (TZ gland), and the peripheral zone (PZ). The correlation between PDE5 expression in the AFMS and clinical data was analysed.

RESULTS

Image analysis revealed that the median ratio of the PDE5-immunoreactive area to smooth muscle area by H&E staining was 74.7% in the AFMS. There was significantly higher PDE5 expression in the AFMS than in the TZ gland (p = 0.034) and PZ (p = 0.002). PDE5 expression in the AFMS was not significantly correlated with age, prostate volume, transition zone volume, or transition zone index. However, older men had a tendency to have higher PDE5 expression in the AFMS.

CONCLUSIONS

We found higher PDE5 expression in the AFMS compared with other prostatic regions, which suggested that the AFMS is a target region of PDE5 inhibitors in the prostate.

Regulation of PDE5 expression in normal prostate, benign prostatic hyperplasia, and adenocarcinoma

BACKGROUND

Type 5 phosphodiesterase (PDE5) expression in the normal and pathological prostate is controversial.

OBJECTIVES

This study aimed at identifying the cell type/s, if any, expressing PDE5 in human healthy or pathological prostate sections in order to further validate the rationale of PDE5 inhibitor (PDE5i) treatment of benign prostatic hyperplasia (BPH) and their safety in the treatment of erectile dysfunction following prostate cancer (PCa) surgery.

MATERIALS AND METHODS

By immunohistochemical analysis, we studied PDE5 expression in tissue microarrays containing sections obtained from healthy, BPH, and PCa samples.

RESULTS

Our results showed that PDE5 is barely expressed in the epithelial or stromal compartment of normal human prostates, but it is highly expressed in the stromal compartment of BPH sections. We also found that a low but significant number of PCa samples (22%) expressed PDE5 in the epithelial cancer cells but not in stromal cells and that such expression was not correlated with the tumor aggressiveness, according to their Gleason score.

DISCUSSION AND CONCLUSION

PDE5 overexpression in the stromal compartment of BPH samples supports the rationale of PDE5 as a target in lower urinary tract symptoms of BPH. PDE5 expression in a significant percentage of PCa samples but the lack of correlation with the Gleason score suggests that this enzyme is not correlated with tumor aggressiveness; however, a role of PDE5 in the minimal residual disease of PCa cannot be excluded.

Benign Prostatic Hyperplasia and Lower Urinary Tract Symptoms: What Is the Role and Significance of Inflammation?

PURPOSE OF REVIEW

The purpose of this review is to summarize the role and significance of inflammation as a putative additional factor contributing to lower urinary tract symptoms and the progression of benign prostatic hyperplasia. We review (1) the histologic definition of prostatic inflammation and its prevalence, (2) the effects inflammation in the prostate including on risk of acute urinary retention, and (3) the effects of systemic inflammation on the prostate and on voiding.

RECENT FINDINGS

Inflammation is a highly prevalent finding in the prostate, both on a histological and biochemical level. Men with inflammation have higher IPSS scores and increased prostate size; however, these differences appear to be imperceptibly small. Men with inflammation do experience a significantly increased risk of developing acute urinary retention, an event that is associated with significant morbidity. Recently, attempts have been made to identify more specific biochemical markers of local inflammation, and to identify regional patterns of inflamed tissue within the prostate which may be associated with higher IPSS scores, accelerated progression, and AUR. The effects of systemic inflammatory states, most notably MetS, and their role in LUTS have also been examined. Inflammation is a common finding in prostates of aging men, but its contribution to lower urinary tract symptoms and benign prostatic hyperplasia progression appears to be small when considered as a clinically relevant entity. Advances in the understanding of different forms of inflammation, and their impact when experienced in different locations within the prostate, may refine this knowledge. Systemic inflammation affects voiding, including in the absence of a prostate, but again significant effects of systemic inflammation on the prostate itself are also difficult to demonstrate. Prostatic inflammation is associated with a significantly increased risk of acute urinary retention.

Tadalafil for the treatment of benign prostatic hyperplasia

INTRODUCTION

In men, lower urinary tract symptoms (LUTS) are primarily attributed to benign prostatic hyperplasia (BPH). Therapeutic options are targeted to relax prostate smooth muscle and/or reduce prostate enlargement. Areas covered: This article reviews the major preclinical and clinical data on PDE5 inhibitors with a specific focus on tadalafil. It includes details of the role of the nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) - PDE5 pathway in the LUT organs (bladder and prostate) in addition to the available data on tadalafil in patients with LUTS secondary to BPH with or without erectile dysfunction (ED). Expert opinion: Preclinical and clinical data have clearly demonstrated that PDE5 inhibitors induce bladder and prostate relaxation, which contributes to the improvement seen in storage symptoms in both animal models of bladder and prostate hypercontractility. Tadalafil is effective both as a monotherapy and add-on therapy in patients with LUTS secondary to BPH. Furthermore, as LUTS-BPH and ED are urological disorders that commonly coexist in aging men, tadalafil is more advantageous than α1-adrenoceptors and should be used as the first option. Tadalafil is a safe and tolerable therapy and unlike α1- adrenoceptors and 5-alpha reductase inhibitors, which can cause sexual dysfunctions, tadalafil improves sexual function.

Upregulated Interleukin 21 Receptor Enhances Proliferation and Epithelial-Mesenchymal Transition Process in Benign Prostatic Hyperplasia

Background: Interleukins (ILs) and related chronic inflammation have been found to contribute to the development of benign prostatic hyperplasia (BPH) in recent decades. As a late member of the ILs family, IL-21 receptor (IL-21R) can modulate cell proliferation, however, IL-21R activity in the prostate has not been examined. The current study aimed to elucidate a potential role of IL-21R in the development of BPH. Material and Methods: Human prostate tissues, cell lines and rats were used. QRT-PCR, Western blot, and immunohistochemistry, along with hematoxylin and eosin, Masson's trichrome, and immunofluorescent staining were performed. BPH-1 cells with IL-21R silenced were cultured or co-cultured with macrophages (active THP-1, AcTHP-1). Apoptosis and cell cycle phases were determined via flow cytometry. Epithelial-mesenchymal transition (EMT) processes were also examined. In vivo, rat prostatitis was induced with intraprostatic injected lipopolysaccharide (LPS). Results: IL-21R was highly expressed in human as well as rat prostate, mainly in the epithelial compartment. BPH concomitant with prostatitis significantly upregulated the expression of IL-21R. Knockdown of IL-21R induced cell apoptosis and cycle arrest at G0/G1 phase, and blocked the EMT process in BPH-1 cells. When IL-21R silenced BPH-1 cells were co-cultured with AcTHP-1 cells, these aforementioned processes and IL-21R change were completely reversed. Prostatic hyperplasia was observed with IL-21R upregulated in LPS induced prostatitis rats. More specifically, the expression of apoptosis, cyclin, and EMT proteins in this rat model are altered in a manner consistent with that seen in the cell line model. Conclusions: Our novel data demonstrates the expression and functional activities of IL-21R in the mechanism for development of BPH. IL-21R mainly localized in prostate epithelium and it was upregulated in hyperplastic prostate tissues. IL-21R enhanced proliferation of BPH-1 cells, via inhibiting cell apoptosis, and modulating cell cycles, as well as the EMT process, in response to inflammatory stimuli.

Androgen Deficiency and Phosphodiesterase Type 5 Expression Changes in Aging Male: Therapeutic Implications

The age-related decline of serum T occurs in ~20-30% of adult men and it is today defined as late-onset hypogonadism (LOH). In the elderly, such decline becomes more prevalent (up to 60%) and shows-up with erectile dysfunction (ED) and hypoactive sexual desire. A large body of experimental evidences have shown that the combination of T replacement therapy (TRT) and phosphodiesterase type 5 inhibitors (PDE5i) is, usually, effective in restoring erectile function in patients with LOH and ED who have not responded to monotherapy for sexual disturbances. In fact, PDE5is potentiate the action of nitric oxide (NO) produced by endothelial cells, resulting in a vasodilator effect, while T facilitates PDE5i effects by increasing the expression of PDE5 in corpora cavernosa. Meta-analytic data have recognized to PDE5i a protective role on the cardiovascular health in patients with decreased left ventricular ejection fraction. In addition, several studies have shown pleiotropic beneficial effects of these drugs throughout the body (i.e., on bones, urogenital tract and cerebral, metabolic, and cardiovascular levels). TRT itself is able to decrease endothelial dysfunction, oxidative stress and inflammation, thus lowering the cardiovascular risk. Furthermore, untreated hypogonadism could be the cause of PDE5i ineffectiveness especially in the elderly. For these reasons, aging men complaining ED who have LOH should undergo TRT before or at the moment when PDE5i treatment is started.

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).

Blebbistatin modulates prostatic cell growth and contrapctility through myosin II signaling

To investigate the effect of blebbistatin (BLEB, a selective myosin inhibitor) on regulating contractility and growth of prostate cells and to provide insight into possible mechanisms associated with these actions. BLEB was incubated with cell lines of BPH-1 and WPMY-1, and intraprostatically injected into rats. Cell growth was determined by flow cytometry, and in vitro organ bath studies were performed to explore muscle contractility. Smooth muscle (SM) myosin isoform (SM1/2, SM-A/B, and LC_17a/b) expression was determined via competitive reverse transcriptase PCR. SM myosin heavy chain (MHC), non-muscle (NM) MHC isoforms (NMMHC-A and NMMHC-B), and proteins related to cell apoptosis were further analyzed via Western blotting. Masson's trichrome staining was applied to tissue sections. BLEB could dose-dependently trigger apoptosis and retard the growth of BPH-1 and WPMY-1. Consistent with in vitro effect, administration of BLEB to the prostate could decrease rat prostatic epithelial and SM cells via increased apoptosis. Western blotting confirmed the effects of BLEB on inducing apoptosis through a mechanism involving MLC₂₀ dephosphorylation with down-regulation of Bcl-2 and up-regulation of BAX and cleaved caspase 3. Meanwhile, NMMHC-A and NMMHC-B, the downstream proteins of MLC₂₀, were found significantly attenuated in BPH-1 and WPMY-1 cells, as well as rat prostate tissues. Additionally, BLEB decreased SM cell number and SM MHC expression, along with attenuated phenylephrine-induced contraction and altered prostate SMM isoform composition with up-regulation of SM-B and down-regulation of LC_17a, favoring a faster contraction. Our novel data demonstrate BLEB regulated myosin expression and functional activity. The mechanism involved MLC₂₀ dephosphorylation and altered SMM isoform composition.

Upregulation of Oxytocin Receptor in the Hyperplastic Prostate

Background: The etiology of benign prostatic hyperplasia (BPH) is complex, both age and androgen are thought to be important. However, the failure of androgen blockade treatments suggests other paracrine/autocrine factors involved in BPH. Oxytocin was found to have a paracrine/autocrine role in prostate in recent years. The influence of BPH on prostatic oxytocin receptor (OTR) expression has never been studied. Material and methods: A testosterone-estradiol induced rat model of BPH was employed and human hyperplastic prostate specimens were harvested. Expressions of OTR, α₁-adrenoreceptor subtypes and nitric oxide synthase isoforms were determined via real-time RT-PCR. OTR was further analyzed with Western-Blotting and histological examination. Subsequently, rat epithelial cells, human stromal cells and epithelial cells were cultured in vitro and treated with gradient concentrations of OT from 1 to 5 days. Cell proliferation was tested by Cell Counting Kit-8 and Flow Cytometry. Results: The rat BPH model was validated with significant increased prostate weight. H-E stain revealed a different histopathology between human and rat BPH. Masson's trichrome staining demonstrated that smooth muscle (SM) cells, epithelium cells and collagen fibers were simultaneously augmented in this rat BPH model and human BPH samples. OTR mainly localized in epithelium in rat prostate whereas it mainly localized in stroma in human prostate. OTR gene was upregulated 3.3-fold in rat BPH and 3.0-fold in human BPH, along with increased expression of 2.0-fold α_1aARs and 3.0-fold eNOS for rat BPH and 5.0-fold α_1aARs for human BPH. The expression of OTR protein was upregulated 1.4-fold in rat BPH and 3.9-fold in human BPH, respectively. Increased concentrations of exogenous OT can accelerate proliferation of rat epithelial cells and human stromal cells but has no impact on human epithelial cells in vitro. Flow Cytometry showed oxytocin could significantly increase G₂/M period cell number. Conclusions: Our novel data demonstrates a significant and previously undocumented upregulation of OTR in both rat and human BPH. Moreover, exogenous OT accelerates proliferation of rat prostate epithelial cells and human prostate stromal cells. It is suggested OTR is involved in the development of BPH and OT regulatory system could be a potential new target for the BPH treatment.

Cinnamomi Cortex (Cinnamomum verum) Suppresses Testosterone-induced Benign Prostatic Hyperplasia by Regulating 5α-reductase

Cinnamomi cortex (dried bark of Cinnamomum verum) is an important drug in Traditional Korean Medicine used to improve blood circulation and Yang Qi. Benign prostatic hyperplasia (BPH) is a common chronic disease in aging men. This study was conducted to determine the effect of Cinnamomi cortex water extract (CC) on BPH. BPH was induced by a pre-4-week daily injection of testosterone propionate (TP). Six weeks of further injection with (a) vehicle, (b) TP, (c) TP + CC, (d) TP + finasteride (Fi) was carried on. As a result, the prostate weight and prostatic index of the CC treatment group were reduced. Histological changes including epithelial thickness and lumen area were recovered as normal by CC treatment. The protein expressions of prostate specific antigen, estrogen receptor α (ERα), androgen receptor (AR), 5α-reductase (5AR), and steroid receptor coactivator 1 were suppressed by treatment of CC. Immunohistochemical assays supported the western blot results, as the expressions of AR and ERα were down-regulated by CC treatment as well. Further in vitro experiments showed CC was able to inhibit proliferation of RWPE-1 cells by suppressing 5AR and AR. These results all together suggest CC as a potential treatment for BPH.