Interleukin-1alpha is a paracrine inducer of FGF7, a key epithelial growth factor in benign prostatic hyperplasia

Intrinsic and extrinsic factors causing hyperplasia of the prostate

Prostatic hyperplasia is very common in elderly men and is a typical disease that reduces quality of life. Histologically, hyperplasia of the prostate gland causes obstruction at the bladder outlet, resulting in symptoms such as a weak urine stream. Various factors have been considered to cause histological enlargement of the prostate, but the underlying cause is still unknown. The factors that cause prostate hyperplasia can be broadly classified into intrinsic and extrinsic ones. Extrinsic factors include things that we directly come into contact with such as bacteria and food. On the other hand, intrinsic factors are those that cause changes in functions originally provided in the body due to some cause, including extrinsic factors, such as chronic inflammation and an imbalance of sex hormones. A large number of reports have been made to date regarding the etiology of prostatic hyperplasia, although they have not yet clarified the fundamental cause(s). The various factors currently known should be outlined for future research. Should it be possible to prevent this highly prevalent prostatic hyperplasia which is mainly cause of dcreasing quality of life, there is no doubt that it would be a huge contribution to humanity.

A Novel Insight into the Immune-Related Interaction of Inflammatory Cytokines in Benign Prostatic Hyperplasia

Benign prostatic hyperplasia (BPH) is a common male condition that impacts many men's quality of life by generating lower urinary tract symptoms (LUTS). In recent years, inflammation has become very common in the prostate, and BPH with inflammation has a higher International Prostate Symptom Score (IPSS) score and an enlarged prostate. Chronic inflammation leads to tissue damage and the release of pro-inflammatory cytokines, which play an important role in the pathogenesis of BPH. We will focus on current advancements in pro-inflammatory cytokines in BPH, as well as the future of pro-inflammatory cytokine research.

Cellular senescence as a possible link between prostate diseases of the ageing male

Senescent cells accumulate with age in all tissues. Although senescent cells undergo cell-cycle arrest, these cells remain metabolically active and their secretome - known as the senescence-associated secretory phenotype - is responsible for a systemic pro-inflammatory state, which contributes to an inflammatory microenvironment. Senescent cells can be found in the ageing prostate and the senescence-associated secretory phenotype and can be linked to BPH and prostate cancer. Indeed, a number of signalling pathways provide biological plausibility for the role of senescence in both BPH and prostate cancer, although proving causality is difficult. The theory of senescence as a mechanism for prostate disease has a number of clinical implications and could offer opportunities for targeting in the future.

ELF3 mediates IL-1α induced differentiation of mesenchymal stem cells to inflammatory iCAFs

Stromal cells in the tumor microenvironment regulate the immune landscape and tumor progression. Yet, the ontogeny and heterogeneity of reactive stromal cells within tumors is not well understood. Carcinoma-associated fibroblasts exhibiting an inflammatory phenotype (iCAFs) have been identified within multiple cancers; however, mechanisms that lead to their recruitment and differentiation also remain undefined. Targeting these mechanisms therapeutically may be important in managing cancer progression. Here, we identify the ELF3 transcription factor as the canonical mediator of IL-1α-induced differentiation of prostate mesenchymal stem cells to an iCAF phenotype, typical of the tumor microenvironment. Furthermore, IL-1α-induced iCAFs were subsequently refractive to TGF-β1 induced trans-differentiation to a myofibroblast phenotype (myCAF), another key carcinoma-associated fibroblast subtype typical of reactive stroma in cancer. Restricted trans-differentiation was associated with phosphorylation of the YAP protein, indicating that interplay between ELF3 action and activation of the Hippo pathway are critical for restricting trans-differentiation of iCAFs. Together, these data show that the IL-1α/ELF3/YAP pathways are coordinate for regulating inflammatory carcinoma-associated fibroblast differentiation.

Single-cell analysis of mouse and human prostate reveals novel fibroblasts with specialized distribution and microenvironment interactions

Stromal-epithelial interactions are critical to the morphogenesis, differentiation, and homeostasis of the prostate, but the molecular identity and anatomy of discrete stromal cell types is poorly understood. Using single-cell RNA sequencing, we identified and validated the in situ localization of three smooth muscle subtypes (prostate smooth muscle, pericytes, and vascular smooth muscle) and two novel fibroblast subtypes in human prostate. Peri-epithelial fibroblasts (APOD+) wrap around epithelial structures, whereas interstitial fibroblasts (C7+) are interspersed in extracellular matrix. In contrast, the mouse displayed three fibroblast subtypes with distinct proximal-distal and lobe-specific distribution patterns. Statistical analysis of mouse and human fibroblasts showed transcriptional correlation between mouse prostate (C3+) and urethral (Lgr5+) fibroblasts and the human interstitial fibroblast subtype. Both urethral fibroblasts (Lgr5+) and ductal fibroblasts (Wnt2+) in the mouse contribute to a proximal Wnt/Tgfb signaling niche that is absent in human prostate. Instead, human peri-epithelial fibroblasts express secreted WNT inhibitors SFRPs and DKK1, which could serve as a buffer against stromal WNT ligands by creating a localized signaling niche around individual prostate glands. We also identified proximal-distal fibroblast density differences in human prostate that could amplify stromal signaling around proximal prostate ducts. In human benign prostatic hyperplasia, fibroblast subtypes upregulate critical immunoregulatory pathways and show distinct distributions in stromal and glandular phenotypes. A detailed taxonomy of leukocytes in benign prostatic hyperplasia reveals an influx of myeloid dendritic cells, T cells and B cells, resembling a mucosal inflammatory disorder. A receptor-ligand interaction analysis of all cell types revealed a central role for fibroblasts in growth factor, morphogen, and chemokine signaling to endothelia, epithelia, and leukocytes. These data are foundational to the development of new therapeutic targets in benign prostatic hyperplasia. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Pharmacological Effects and Potential Clinical Usefulness of Polyphenols in Benign Prostatic Hyperplasia

Benign prostatic hyperplasia (BPH) is arguably the most common benign disease among men. This disease is often associated with lower urinary tract symptoms (LUTS) in men and significantly decreases the quality of life. Polyphenol consumption reportedly plays an important role in the prevention of many diseases, including BPH. In recent years, in addition to disease prevention, many studies have reported the efficacy and safety of polyphenol treatment against various pathological conditions in vivo and in vitro. Furthermore, numerous studies have also revealed the molecular mechanisms of the antioxidant and anti-inflammatory effects of polyphenols. We believe that an improved understanding of the detailed pharmacological roles of polyphenol-induced activities at a molecular level is important for the prevention and treatment of BPH. Polyphenols are composed of many members, and their biological roles differ. In this review, we first provide information regarding the pathological roles of oxidative stress and inflammation in BPH. Next, the antioxidant and anti-inflammatory effects of polyphenols, including those of flavonoids and non-flavonoids, are discussed. Finally, we talk about the results and limitations of previous clinical trials that have used polyphenols in BPH, with particular focus on their molecular mechanisms of action.

Inflammation driven tumor-like signaling in prostatic epithelial cells by sexually transmitted Trichomonas vaginalis

OBJECTIVES

To identify the sequence of inflammation-driven signaling cascades and other molecular events that might cause tumor-like transformation of prostatic cells.

METHODS

Cytokine array analysis, Reactome and STRING analysis, immunoblotting, and immunocytochemistry were used to investigate the molecular mechanisms governing inflammation-driven adverse changes in human prostatic cells caused by the sexually transmitted infection, Trichomonas vaginalis, resulting in prostatitis, benign prostatic hyperplasia and prostate cancer.

RESULTS

Array analysis showed upregulation of 23 cytokines within 24 h of infection of human prostatic epithelial RWPE-1 cells with the parasite, in vitro. Reactome and STRING analysis of array data identified interleukin-6, interleukin-8, nuclear factor kappa B, signal transducer and activator of transcription 3 and cyclooxygenase 2 as chief instigators of prostatic anomaly, which were found to be significantly upregulated by immunofluorescence and western blotting analyses. STRING further connected these instigators with macrophage migration inhibitory factor, PIM-1 and prostate-specific antigen; which was confirmed by their marked stimulation in infected prostatic cells by immunoblotting and immunocytochemistry. Upregulated proliferation markers, such as Ki67, proliferating cell nuclear antigen and B-cell lymphoma 2, suggested tumor-like signaling in infected RWPE-1 cells, which was further supported by downregulation of E-cadherin, upregulation of vimentin and activation of focal adhesion kinase. Prostate tumor DU145 cells were more sensitive to parasite invasion, and showed rapid upregulation with nuclear translocation of sensitive parameters, such as nuclear factor kappa B, signal transducer and activator of transcription 3, and macrophage migration inhibitory factor. The migration of DU145 cells augmented when incubated in spent media from parasite-infected RWPE-1 cells.

CONCLUSION

The initiation of inflammation driven tumor-like cell signaling in parasite-infected human prostatic epithelial cells is apparent, with the prostate tumor (DU145) cells being more sensitive to T. vaginalis than normal (RWPE-1) prostatic cells.

Cellular Senescence in Renal and Urinary Tract Disorders

Cellular senescence is a state of cell cycle arrest induced by repetitive cell mitoses or different stresses, which is implicated in various physiological or pathological processes. The beneficial or adverse effects of senescent cells depend on their transitory or persistent state. Transient senescence has major beneficial roles promoting successful post-injury repair and inhibiting malignant transformation. On the other hand, persistent accumulation of senescent cells has been associated with chronic diseases and age-related illnesses like renal/urinary tract disorders. The deleterious effects of persistent senescent cells have been related, in part, to their senescence-associated secretory phenotype (SASP) characterized by the release of a variety of factors responsible for chronic inflammation, extracellular matrix adverse remodeling, and fibrosis. Recently, an increase in senescent cell burden has been reported in renal, prostate, and bladder disorders. In this review, we will summarize the molecular mechanisms of senescence and their implication in renal and urinary tract diseases. We will also discuss the differential impacts of transient versus persistent status of cellular senescence, as well as the therapeutic potential of senescent cell targeting in these diseases.

Differential impact of paired patient-derived BPH and normal adjacent stromal cells on benign prostatic epithelial cell growth in 3D culture

BACKGROUND

Benign prostatic hyperplasia (BPH) is an age-related disease characterized by nonmalignant abnormal growth of the prostate, which is also frequently associated with lower urinary tract symptoms. The prostate with BPH exhibits enhanced growth not only in the epithelium but also in the stroma, and stromal-epithelial interactions are thought to play an important role in BPH pathogenesis. However, our understanding of the mechanisms of stromal-epithelial interactions in the development and progression of BPH is very limited.

METHODS

Matched pairs of glandular BPH and normal adjacent prostate specimens were obtained from BPH patients undergoing simple prostatectomy for symptomatic BPH. Tissues were divided further into fresh specimens for culture of primary prostatic stromal cells, and specimens were embedded in paraffin for immunohistochemical analyses. Proliferation assays, immunohistochemistry, and immunoblotting were used to characterize the primary prostate stromal cells and tissue sections. Coculture of the primary stromal cells with benign human prostate epithelial cell lines BHPrE1 or BPH-1 was performed in three-dimensional (3D) Matrigel to determine the impact of primary stromal cells derived from BPH on epithelial proliferation. The effect of stromal-conditioned medium (CM) on BHPrE1 and BPH-1 cell growth was tested in 3D Matrigel as well.

RESULTS

BPH stromal cells expressed less smooth muscle actin and calponin and increased vimentin, exhibiting a more fibroblast and myofibroblast phenotype compared with normal adjacent stromal cells both in culture and in corresponding paraffin sections. Epithelial spheroids formed in 3D cocultures with primary BPH stromal cells were larger than those formed in coculture with primary normal stromal cells. Furthermore, CM from BPH stromal cells stimulated epithelial cell growth while CM from normal primary stromal cells did not in 3D culture.

CONCLUSIONS

These findings suggest that the stromal cells in BPH tissues are different from normal adjacent stromal cells and could promote epithelial cell proliferation, potentially contributing to the development and progression of BPH.

Benign prostatic hyperplasia - what do we know?

OBJECTIVES

To present historical and contemporary hypotheses on the pathogenesis of benign prostatic hyperplasia (BPH), and the potential implications for current medical therapies.

METHODS

The literature on BPH was reviewed. BPH is a prevalent disease with significant health and economic impacts on patients and health organisations across the world, whilst the cause/initiation of the disease process has still not been fully determined.

RESULTS

In BPH, pathways involving androgens, oestrogens, insulin, inflammation, proliferative reawakening, stem cells and telomerase have been hypothesised in the pathogenesis of the disease. A number of pathways first described >40 years ago have been first rebuked and then have come back into favour. A system of an inflammatory process within the prostate, which leads to growth factor production, stem cell activation, and cellular proliferation encompassing a number of pathways, is currently in vogue. This review also highlights the physiology of the prostate cell subpopulations and how this may account for the delay/failure in treatment response for certain medical therapies.

CONCLUSION

BPH is an important disease, and as the pathogenesis is not fully understood it impacts the effectiveness of medical therapies. This impacts patients, with further research potentially highlighting novel therapeutic avenues.

The FGF/FGFR system in the physiopathology of the prostate gland

Fibroblast growth factors (FGFs) are a family of proteins possessing paracrine, autocrine, or endocrine functions in a variety of biological processes, including embryonic development, angiogenesis, tissue homeostasis, wound repair, and cancer. Canonical FGFs bind and activate tyrosine kinase FGF receptors (FGFRs), triggering intracellular signaling cascades that mediate their biological activity. Experimental evidence indicates that FGFs play a complex role in the physiopathology of the prostate gland that ranges from essential functions during embryonic development to modulation of neoplastic transformation. The use of ligand- and receptor-deleted mouse models has highlighted the requirement for FGF signaling in the normal development of the prostate gland. In adult prostate, the maintenance of a functional FGF/FGFR signaling axis is critical for organ homeostasis and function, as its disruption leads to prostate hyperplasia and may contribute to cancer progression and metastatic dissemination. Dissection of the molecular landscape modulated by the FGF family will facilitate ongoing translational efforts directed toward prostate cancer therapy.

Aryl Hydrocarbon Receptor Mediates Larval Zebrafish Fin Duplication Following Exposure to Benzofluoranthenes

The aryl hydrocarbon receptor (AHR) mediates developmental toxicity of several xenobiotic classes including polycyclic aromatic hydrocarbons. Using embryonic zebrafish, we previously identified 4 polycyclic aromatic hydrocarbons that caused a novel phenotype among AHR ligands-growth of a lateral, duplicate caudal fin fold. The window of sensitivity to the most potent inducer of this phenotype, benzo[k]fluoranthene (BkF), was prior to 36 h postfertilization (hpf), although the phenotype was not manifest until 60 hpf. AHR dependency via Ahr2 was demonstrated using morpholino knockdown. Hepatocyte ablation demonstrated that hepatic metabolism of BkF was not required for the phenotype, nor was it responsible for the window of sensitivity. RNA sequencing performed on caudal trunk tissue from BkF-exposed animals collected at 48, 60, 72, and 96 hpf showed upregulation of genes associated with AHR activation, appendage development, and tissue patterning. Genes encoding fibroblast growth factor and bone morphogenic protein ligands, along with retinaldehyde dehydrogenase, were prominently upregulated. Gene Ontology term analysis revealed that upregulated genes were enriched for mesoderm development and fin regeneration, whereas downregulated genes were enriched for Wnt signaling and neuronal development. MetaCore (Clarivate Analytics) systems analysis of orthologous human genes predicted that R-SMADs, AP-1, and LEF1 regulated the expression of an enriched number of gene targets across all time points. Our results demonstrate a novel aspect of AHR activity with implications for developmental processes conserved across vertebrate species.

Inflammatory mediators in the development and progression of benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is the most common urological disease in elderly men. Epidemiological data suggest a causal link between this condition and prostatic inflammation. The prostate is an immune-competent organ characterized by the presence of a complex immune system. Several stimuli, including infectious agents, urinary reflux, metabolic syndrome, the ageing process, and autoimmune response, have been described as triggers for the dysregulation of the prostatic immune system via different molecular pathways involving the development of inflammatory infiltrates. From a pathophysiological standpoint, subsequent tissue damage and chronic tissue healing could result in the development of BPH nodules.

Specific expression pattern of tissue cytokines analyzed through the Surface Acoustic Wave technique is associated with age-related spontaneous benign prostatic hyperplasia in rats

The aim of the study reported herein was to evaluate the suitability of the Surface Acoustic Wave (SAW) technique as a possible diagnostic tool in benign prostatic hyperplasia (BPH). Moreover, for the first time, the BPH model was a totally physiological using naturally aged rats with spontaneous, age-related BPH instead of the pharmacologically induced models usually used. Eighteen male Wistar rats were distributed according to their age: 6 weeks (young), 12 weeks (adult) and 12 months (old) old. Prostate gland was removed and analyzed by mini-arrays, Western blotting (WB) and SAW techniques. Mini-arrays indicated that there were significant differences in the expression of 29/34 inflammation-related cytokines. WB was carried out to confirm the results after selection of 4 cytokines from which one showed no changes, namely PDGF-AA, and the other three, which significantly increase in older animals, were CD86, β-NGF and VEGF. Notwithstanding, WB of old rats yielded confusing results due to an anomalous migration of proteins, dismissing this technique as an useful tool in these animals. Accurate results in old rats were uniquely obtained by using the SAW technique. Thus, SAW analysis showed that there were not differences among groups in the amount of PDGF-AA. On the contrary, SAW analysis showed that amounts of CD86, β-NGF and VEGF in old rats were 2.0, 1.9 and 5.7-fold higher than that from young ones, respectively. These results indicate that SAW is a highly accurate technique for determining changes in the cytokines expression in BPH.

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Diagnosis of prostate alterations can be improved by using the SAW technique.

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Study of prostate alterations can be optimized by using an age-related animal model.

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VEGF is a sensitive marker of bening prostatic hyperplasia.

Inflammation and Prostate Cancer

Chronic inflammation resulting from infections, altered metabolism, inflammatory diseases or other environmental factors can be a major contributor to the development of several types of cancer. In fact around 20% of all cancers are linked to some form of inflammation. Evidence gathered from genetic, epidemiological and molecular pathological studies suggest that inflammation plays a crucial role at various stages of prostatic carcinogenesis and tumor progression. These include initiation, promotion, malignant conversion, invasion, and metastasis. Detailed basic and clinical research in these areas, focused towards understanding the etiology of prostatic inflammation, as well as the exact roles that various signaling pathways play in promoting tumor growth, is critical for understanding this complex process. The information gained would be useful in developing novel therapeutic strategies such as molecular targeting of inflammatory mediators and immunotherapy-based approaches.

Conditional knock out of N-WASP in keratinocytes causes skin barrier defects and atopic dermatitis-like inflammation

Neural-Wiskott Aldrich Syndrome Protein (N-WASP) is expressed ubiquitously and regulates actin cytoskeleton remodeling. In order to characterize the role of N-WASP in epidermal homeostasis and cutaneous biology, we generated conditional N-WASP knockout mouse using CK14-cre (cytokeratin 14) to ablate expression of N-WASP in keratinocytes. N-WASP^K14KO (N-WASP^fl/fl; CK14-Cre) mice were born following Mendelian genetics suggesting that N-WASP expression in keratinocytes is not essential during embryogenesis. N-WASP^K14KO mice exhibited stunted growth, alopecia, dry and wrinkled skin. The dry skin in N-WASP^K14KO mice is probably due to increased transepidermal water loss (TEWL) caused by barrier function defects as revealed by dye penetration assay. N-WASP^K14KO mice developed spontaneous inflammation in the neck and face 10 weeks after birth. Histological staining revealed thickening of the epidermis, abnormal cornified layer and extensive infiltration of immune cells (mast cells, eosinophils and T-lymphocytes) in N-WASP^K14KO mice skin compared to control mice. N-WASP^K14KO mice had higher serum levels of IL-1α, TNF-α, IL-6 and IL-17 compared to control mice. Thus our results suggest that conditional N-WASP knockout in keratinocytes leads to compromised skin barrier, higher infiltration of immune cells and hyperproliferation of keratinocytes due to increased production of cytokines highlighting the importance of N-WASP in maintaining the skin homeostasis.

Non-Cell-Autonomous Regulation of Prostate Epithelial Homeostasis by Androgen Receptor

Prostate inflammation has been suggested as an etiology for benign prostatic hyperplasia (BPH). We show that decreased expression of the androgen receptor (AR) in luminal cells of human BPH specimens correlates with a higher degree of regional prostatic inflammation. However, the cause-and-effect relationship between the two events remains unclear. We investigated specifically whether attenuating AR activity in prostate luminal cells induces inflammation. Disrupting luminal cell AR signaling in mouse models promotes cytokine production cell-autonomously, impairs epithelial barrier function, and induces immune cell infiltration, which further augments local production of cytokines and chemokines including Il-1 and Ccl2. This inflammatory microenvironment promotes AR-independent prostatic epithelial proliferation, which can be abolished by ablating IL-1 signaling or depleting its major cellular source, the macrophages. This study demonstrates that disrupting luminal AR signaling promotes prostate inflammation, which may serve as a mechanism for resistance to androgen-targeted therapy for prostate-related diseases.

Endocrine control of benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is the most common benign proliferative disease among aging men. Androgens play a key role in the development and growth of the male genital tract favoring differentiation and proliferation of stromal and epithelial cells of the prostate gland. It is known that growth factors play a crucial role in the cross-talk between stromal cells and epithelial cells. These factors, mainly secreted by stromal cells, act in an autocrine/paracrine manner to maintain prostate cellular homeostasis. A number of experimental studies support the interdependence between growth factors (IGF, FGF, TGF) and the steroid hormone milieu of the prostate. Alterations of these interactions may alter the balance between proliferation and cell death leading to the development of BPH. The onset of BPH is closely related to an inflammatory microenvironment. Chronic inflammation, which generally follows the acute inflammation because of infectious agents, is favored by hormonal or metabolic abnormalities. However, a close correlation between these mechanisms and metabolic or sexual hormones (androgen/estrogen ratio) alteration has been shown suggesting a key role of hypogonadism in the development of prostate inflammation. This review clear shows that the BPH pathogenesis and the subsequent onset of the lower urinary tract symptoms (LUTS) depends from different etio-pathogenetic factors whose mechanism of action remains to be evaluated.

Oxidative stress promotes benign prostatic hyperplasia

BACKGROUND

Benign prostatic hyperplasia (BPH) is characterized by increased tissue mass in the transition zone of the prostate, which leads to obstruction of urine outflow and significant morbidity in the majority of older men. Plasma markers of oxidative stress are increased in men with BPH but it is unclear whether oxidative stress and/or oxidative DNA damage are causal in the pathogenesis of BPH.

METHODS

Levels of 8-OH deoxyguanosine (8-OH dG), a marker of oxidative stress, were measured in prostate tissues from normal transition zone and BPH by ELISA. 8-OH dG was also detected in tissues by immunohistochemistry and staining quantitated by image analysis. Nox4 promotes the formation of reactive oxygen species. We therefore created and characterized transgenic mice with prostate specific expression of Nox4 under the control of the prostate specific ARR2PB promoter.

RESULTS

Human BPH tissues contained significantly higher levels of 8-OH dG than control transition zone tissues and the levels of 8-OH dG were correlated with prostate weight. Cells with 8-OH dG staining were predominantly in the epithelium and were present in a patchy distribution. The total fraction of epithelial staining with 8-OH dG was significantly increased in BPH tissues by image analysis. The ARR2PB-Nox4 mice had increased oxidative DNA damage in the prostate, increased prostate weight, increased epithelial proliferation, and histological changes including epithelial proliferation, stromal thickening, and fibrosis when compared to wild type controls.

CONCLUSIONS

Oxidative stress and oxidative DNA damage are important in the pathogenesis of BPH.

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.

The role of prostatic inflammation biomarkers in the diagnosis of prostate diseases

Benign prostatic hyperplasia (BPH) and prostate cancer (PCa) are chronic conditions, which are hormone-dependent and epidemiologically associated with prostate inflammation. As a large number of studies have demonstrated, the stimulation of T-cells at the level of prostatic chronic inflammatory infiltrates is followed by stromal and epithelial cell proliferation. The aim of this review is to present the actual level of knowledge in the field of prostatic immune response and chronic inflammation, and to analyze the relationships between chronic inflammation and BPH/PCa. The most studied prostatic inflammation biomarkers detected in biological fluids are also presented, together with their potential roles in the diagnosis and prognosis of prostatic disease.

The senescence-associated secretory phenotype promotes benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is characterized by increased tissue mass in the transition zone of the prostate, which leads to obstruction of urine outflow and considerable morbidity in a majority of older men. Senescent cells accumulate in human tissues, including the prostate, with increasing age. Expression of proinflammatory cytokines is increased in these senescent cells, a manifestation of the senescence-associated secretory phenotype. Multiplex analysis revealed that multiple cytokines are increased in BPH, including GM-CSF, IL-1α, and IL-4, and that these are also increased in senescent prostatic epithelial cells in vitro. Tissue levels of these cytokines were correlated with a marker of senescence (cathepsin D), which was also strongly correlated with prostate weight. IHC analysis revealed the multifocal epithelial expression of cathepsin D and coexpression with IL-1α in BPH tissues. In tissue recombination studies in nude mice with immortalized prostatic epithelial cells expressing IL-1α and prostatic stromal cells, both epithelial and stromal cells exhibited increased growth. Expression of IL-1α in prostatic epithelial cells in a transgenic mouse model resulted in increased prostate size and bladder obstruction. In summary, both correlative and functional evidence support the hypothesis that the senescence-associated secretory phenotype can promote the development of BPH, which is the single most common age-related pathology in older men.

Pathogenic intestinal bacteria enhance prostate cancer development via systemic activation of immune cells in mice

A role for microbes has been suspected in prostate cancer but difficult to confirm in human patients. We show here that a gastrointestinal (GI) tract bacterial infection is sufficient to enhance prostate intraepithelial neoplasia (PIN) and microinvasive carcinoma in a mouse model. We found that animals with a genetic predilection for dysregulation of wnt signaling, Apc^Min/+ mutant mice, were significantly susceptible to prostate cancer in an inflammation-dependent manner following infection with Helicobacter hepaticus. Further, early neoplasia observed in infected Apc^Min/+ mice was transmissible to uninfected mice by intraperitoneal injection of mesenteric lymph node (MLN) cells alone from H. hepaticus-infected mutant mice. Transmissibility of neoplasia was preventable by prior neutralization of inflammation using anti-TNF-α antibody in infected MLN donor mice. Taken together, these data confirm that systemic inflammation triggered by GI tract bacteria plays a pivotal role in tumorigenesis of the prostate gland.

Action Mechanism of Ginkgo biloba Leaf Extract Intervened by Exercise Therapy in Treatment of Benign Prostate Hyperplasia

Benign prostatic hyperplasia (BPH), an imbalance between androgen/estrogen, overexpression of stromal, and epithelial growth factors associated with chronic inflammation, has become an atypical direct cause of mortality of aged male diseases. Ginkgo possesses anti-inflammatory, blood flow-enhancing, and free radical scavenging effects. Considering strenuous exercise can reduce BPH risks, we hypothesize Ginkgo + exercise (Ginkgo + Ex) could be beneficial to BPH. To verify this, rat BPH model was induced by s.c. 3.5 mg testosterone (T) and 0.1 mg estradiol (E2) per head per day successively for 8 weeks, using mineral oil as placebo. Cerenin^® 8.33 μL/100 g was applied s.c. from the 10th to the 13th week, and simultaneously, Ex was applied (30 m/min, 3 times/week). In BPH, Ginkgo alone had no effect on T, 5α-reductase, and dihydrotestosterone (DHT), but suppressed androgen receptor (AR), aromatase, E2 and estrogen receptor (ER), and the proliferating cell nuclear antigen (PCNA); Ex alone significantly reduced T, aromatase, E2, ER, AR, and PCNA, but highly raised DHT. While Ginkgo + Ex androgenically downregulated T, aromatase, E2, and ER, but upregulated DHT, AR, and PCNA, implying Ginkgo + Ex tended to worsen BPH. Conclusively, Ginkgo or Ex alone may be more beneficial than Ginkgo + Ex for treatment of BPH.

Acute bacterial inflammation of the mouse prostate

BACKGROUND

Prostatic inflammation is gaining increasing attention as a potential etiologic factor in prostate cancer, benign prostatic hyperplasia, lower urinary tract symptoms, and CPPS. This study was performed to address the need for a well characterized model of acute prostatic inflammation that may be used to study the effect of acute inflammation on epithelial and stromal cell proliferation, voiding behavior, and neurovascular physiology.

METHODS

Uropathogenic E. coli 1677 was instilled transurethrally into adult C57BL/6J male mice. Prostates were analyzed at 1, 2, 3, 5, 7, or 14 days post-instillation and compared to saline-instilled and naïve controls. Time course and severity of inflammation were characterized by the quantity and type of inflammatory infiltrate present, hemorrhage, proliferation, and reactive hyperplasia. RT-PCR was performed to characterize inflammatory mediators including IL-1α, IL-1β, IL-1RA, IL-18, IL-6, IL-10, IL-8, TNFα, and COX-2.

RESULTS

Inflammation was evident in all lobes of the prostate with the DLP most severely affected. Infection consistently led to a significant increase in neutrophils and macrophages in the early stages of prostate infection, followed by lymphocytic inflammation at the later time points. Inflammation was accompanied by induction of several inflammatory genes, including IL-1 family members, IL-6, and COX-2, and induced a significant increase in epithelial proliferation and reactive hyperplasia in all three prostate lobes.

CONCLUSIONS

Transurethral inoculation of uropathogenic E. coli 1677 reliably infects the mouse prostate, produces a significant inflammatory response, and induces quantifiable epithelial proliferation and reactive hyperplasia.

The functional role of reactive stroma in benign prostatic hyperplasia

The human prostate gland is one of the only internal organs that continue to enlarge throughout adulthood. The specific mechanisms that regulate this growth, as well as the pathological changes leading to the phenotype observed in the disease benign prostatic hyperplasia (BPH), are essentially unknown. Recent studies and their associated findings have made clear that many complex alterations occur, involving persistent and chronic inflammation, circulating hormonal level deregulation, and aberrant wound repair processes. BPH has been etiologically characterized as a progressive, albeit discontinuous, hyperplasia of both the glandular epithelial and the stromal cell compartments coordinately yielding an expansion of the prostate gland and clinical symptoms. Interestingly, the inflammatory and repair responses observed in BPH are also key components of general wound repair in post-natal tissues. These responses include altered expression of chemokines, cytokines, matrix remodeling factors, chronic inflammatory processes, altered immune surveillance and recognition, as well as the formation of a prototypical 'reactive' stroma, which is similar to that observed across various fibroplasias and malignancies of a variety of tissue sites. Stromal tissue, both embryonic mesenchyme and adult reactive stroma myofibroblasts, has been shown to exert potent and functional regulatory control over epithelial proliferation and differentiation as well as immunoresponsive modulation. Thus, the functional biology of a reactive stroma, within the context of an adult disease typified by epithelial and stromal aberrant hyperplasia, is critical to understand within the context of prostate disease and beyond. The mechanisms that regulate reactive stroma biology in BPH represent targets of opportunity for new therapeutic approaches that may extend to other tissue contexts. Accordingly, this review seeks to address the dissection of important factors, signaling pathways, genes, and other regulatory components that mediate the interplay between epithelium and stromal responses in BPH.

LHRH antagonist Cetrorelix reduces prostate size and gene expression of proinflammatory cytokines and growth factors in a rat model of benign prostatic hyperplasia

BACKGROUND

Recent findings suggest that BPH has an inflammatory component. Clinical trials have documented that therapy with LHRH antagonist Cetrorelix causes a marked and prolonged improvement in LUTS in men with symptomatic BPH. We investigated the mechanism of action and effect of Cetrorelix in a rat model of BPH.

METHODS

Adult male Wistar rats were used. BPH was induced in rats by subcutaneous injections of TE 2 mg/day for 4 weeks. Control animals received injections of corn oil. After induction of BPH, rats received depot Cetrorelix pamoate at the doses of 0.625, 1.25, and 12.5 mg/kg on days 1 and 22 and TE-control rats received vehicle injections. Whole prostates were weighed and processed for RNA and protein. Real-time RT-PCR assays for numerous inflammatory cytokines and growth factors were performed. Quantitative analyses of prostatic LHRH receptor, LHRH, androgen receptor (AR) and 5α-reductase 2 were done by real-time RT-PCR and immunoblotting; serum DHT, LH, PSA, and IGF-1 by immunoassays.

RESULTS

mRNA levels for inflammatory cytokines IFN-γ, IL-3, IL-4, IL-5, IL-6, IL-8, IL-13, IL-15, and IL-17 and for growth factors EGF, FGF-2, FGF-7, FGF-8, FGF-14, TGF-β1, and VEGF-A were significantly reduced by Cetrorelix 0.625 mg/kg (P < 0.05). Prostate weights were also significantly lowered by any dose of Cetrorelix.

CONCLUSIONS

This study suggests that Cetrorelix reduces various inflammatory cytokines and growth factors in rat prostate and, at doses which do not induce castration levels of testosterone, can lower prostate weights. Our findings shed light on the mechanism of action of LHRH antagonists in BPH.

Polymorphisms of pro-inflammatory genes and prostate cancer risk: a pharmacogenomic approach

In this paper, we consider the role of the genetics of inflammation in the pathophysiology of prostate cancer (PCa). This paper is not an extensive review of the literature, rather it is an expert opinion based on data from authors' laboratories on age-related diseases and inflammation. The aim is the detection of a risk profile that potentially allows both the early identification of individuals at risk for disease and the possible discovery of potential targets for medication. In fact, a major goal of clinical research is to improve early detection of age-related diseases, cancer included, by developing tools to move diagnosis backward in disease temporal course, i.e., before the clinical manifestation of the malady, where treatment might play a decisive role in preventing or significantly retarding the manifestation of the disease. The better understanding of the function and the regulation of inflammatory pathway in PCa may help to know the mechanisms of its formation and progression, as well as to identify new targets for the refinement of new treatment such as the pharmacogenomics approach.

Cell surface-bound IL-1alpha is an upstream regulator of the senescence-associated IL-6/IL-8 cytokine network

Inflammation underlies most age-related diseases, including cancer, but the etiology is poorly understood. One proposed factor is the presence of senescent cells, which increase with age. The senescence response arrests the proliferation of potentially oncogenic cells, and most senescent cells secrete high levels of proinflammatory cytokines and other proteins. The complex senescence-associated secretory phenotype is likely regulated at multiple levels, most of which are unknown. We show that cell surface-bound IL-1alpha is essential for signaling the senescence-associated secretion of IL-6 and IL-8, 2 proinflammatory cytokines that also reinforce the senescence growth arrest. Senescent human fibroblasts expressed high levels of IL-1alpha mRNA, intracellular protein, and cell surface-associated protein, but secreted very little protein. An IL-1 receptor (IL1R) antagonist, neutralizing IL-1alpha antibodies, and IL-1alpha depletion by RNA interference all markedly reduced senescence-associated IL-6/IL-8 secretion. Depletion of the key IL-1R signaling component IRAK1 also suppressed this secretion, and IL-1alpha neutralizing antibodies prevented IRAK1 degradation, indicating engagement of the IL-1R signaling pathway. Furthermore, IL-1alpha depletion reduced the DNA binding activity of NF-kappaB and C/EBPbeta, which stimulate IL-6/IL-8 transcription. IL-1alpha was a general regulator of senescence-associated IL-6/IL-8 secretion because IL-1alpha blockade reduced IL-6/IL-8 secretion whether cells senesced owing to DNA damage, replicative exhaustion, oncogenic RAS, or chromatin relaxation. Furthermore, conditioned medium from IL-1alpha-depleted senescent cells markedly reduced the IL-6/IL-8-dependent invasiveness of metastatic cancer cells, indicating that IL-1alpha regulates the biological effects of these cytokines. Thus, cell surface IL-1alpha is an essential cell-autonomous regulator of the senescence-associated IL-6/IL-8 cytokine network.

Ovarian cancer cells stimulate uPA gene expression in fibroblastic stromal cells via multiple paracrine and autocrine mechanisms. Gynecol Oncol. 2009;115:121-126. [PMID: 19631971 DOI: 10.1016/j.ygyno.2009.06.026]

OBJECTIVES

Expression of uPA mRNA is massively up-regulated in the stroma of poorly differentiated ovarian tumors. We hypothesized that this expression was induced by paracrine signals from the epithelial tumor cells, and established an in vitro model of ovarian cancer microenvironment to study intercellular cross-talk.

METHODS

ES-2 clear cell carcinoma cells were grown in tissue culture inserts in a double-chamber system with fibroblastic stromal LEP cells embedded in Matrigel. Binding-site directed antibodies were used to neutralize soluble cytokines in ES-2 conditioned medium (CM) before incubation with LEP cells. Real time PCR measured uPA mRNA in LEP cells, as well as mRNA for cytokines in both cell types.

RESULTS

Co-culture with ES-2 cells as well as incubation with ES-2 CM induced uPA mRNA in LEP cells about two-fold. In short time (12 h) incubation of LEP cells with CM, antibodies to EGF and bFGF reduced induction of uPA mRNA, suggesting that these cytokines function as paracrine signals. EGF mRNA and bFGF mRNA were also found in ES-2 cells. At longer incubation (24 h) antibodies to bFGF, HB-EGF, HGF, IGF-1, and IL-1alpha reduced uPA mRNA induction, suggesting an autocrine function for these cytokines in LEP cells. In fact, expression of the same five cytokines was up-regulated in LEP cells exposed to CM.

CONCLUSION

We identified two cytokines as paracrine signals, and five cytokines as autocrine signals in ovarian cancer cell induced up-regulation of uPA mRNA in stromal fibroblastic cells. It is crucial to understand intra-tumoral cross-talk, since it can offer new therapeutic approaches.

CCL5 secreted by senescent aged fibroblasts induces proliferation of prostate epithelial cells and expression of genes that modulate angiogenesis

There is increased interest in the effects of secretory products from aged cells on promoting both benign and malignant cell growth. We identified a human fibroblast line, AG04382, from an aged donor that naturally demonstrated senescence-associated features and whose conditioned media significantly induced proliferation of benign prostatic hyperplasia (BPH1) cells. Candidate cytokines mediating this effect were identified with protein arrays and validated by ELISA. We found that the AG04382 fibroblast line secreted high levels of CXCL5, CCL5, and CCL2, but relative to the other lines, its conditioned media was unique in its increased expression of CCL5. Blocking studies using specific antibodies against CXCL5, CCL5, and CCL2 in the conditioned media of AG04382 showed that only CCL5 contributed significantly to BPH1 proliferation. Stimulation of BPH1 cells with rhuCCL5 resulted in increased proliferation and migration, as well as significant changes in the expression of genes that influence angiogenesis. These data suggest that CCL5 is a candidate chemokine secreted by aged cells that promotes prostate growth and regulates angiogenesis.

Chronic inflammation in the pathogenesis of benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is a common disorder affecting 50-80% of the aged male population. Androgens and age have been traditionally considered the main determinants of prostate enlargement, but in the last years a potentially important role of chronic inflammation in BPH pathogenesis has emerged. Bacterial and non-infectious chronic prostatitis could represent inciting factors leading to tissue hyperproliferation, possibly via the recently demonstrated antigen-presenting capacity of prostatic stromal cells, enabling them to induce and sustain intraglandular immune responses. The prostate growth-promoting chemokine IL-8 could represent a direct link between chronic prostate inflammation and autocrine/paracrine stromal cell proliferation, in agreement with its marked secretion induced in BPH stromal cells by a combination of Th1 and Th17 cell-derived inflammatory cytokines. BPH stromal cells express the vitamin D receptor (VDR), which is up-regulated by exposure to inflammatory stimuli. The non-hypercalcaemic VDR agonist elocalcitol, shown to arrest BPH development by decreasing the intra-prostatic androgen signalling without directly interfering with systemic androgen action, exerts immunoregulatory and anti-inflammatory properties in different prostatic pathology characterized by growth and inflammation. The mechanism of action of VDR agonists supports an important role of chronic inflammation in BPH pathogenesis and strengthens the concept of these agents as a therapeutic option for pharmacological treatment of BPH.

Human benign prostatic hyperplasia stromal cells as inducers and targets of chronic immuno-mediated inflammation

Benign prostatic hyperplasia (BPH), a highly prevalent prostatic condition, could involve an inflammatory component in disease pathogenesis. In this study, we show that human stromal prostate cells obtained from BPH tissue can actively contribute to the inflammatory process by secreting proinflammatory cytokines as well as chemokines able to recruit lymphomonuclear cells and by acting as APCs. BPH cells express all of the TLRs and their ligation leads to the secretion of CXCL8/IL-8, CXCL10, and IL-6. In addition, BPH cells express costimulatory as well as class I and class II MHC molecules, which activate alloreactive CD4(+) cells that in turn markedly up-regulate IL-12/IL-23p40 and IL-12p75 secretion by BPH cells. Alloreactive CD4(+) cells activated by BPH cells secrete IFN-gamma and IL-17. These cytokines up-regulate IL-6, IL-8, and CXCL10 production by BPH cells, creating a positive feedback loop that can amplify inflammation. IL-8 induces autocrine/paracrine proliferation of BPH cells, indicating also a growth-promoting activity of this chemokine in disease pathogenesis. These results show that human BPH cells represent nonprofessional APCs able to induce and sustain chronic inflammatory processes, supporting the relevance of inflammation in BPH pathogenesis.

Protease-activated receptor-1 upregulates fibroblast growth factor 7 in stroma of benign prostatic hyperplasia

BACKGROUND

Benign prostatic hyperplasia (BPH) is characterized by abnormal epithelial and stromal proliferation causing urinary obstruction. Prostate growth is regulated by a variety of growth factors secreted from the stroma, including fibroblast growth factor 7 (FGF-7), a potent epithelial-specific growth factor which is increased in hyperplastic prostate. However, the mediator(s) of FGF-7 over-expression is unclear. Protease-activated receptor-1 (PAR-1) is a G-protein coupled receptor known to induce multiple biological processes, but its effect on BPH pathogenesis is mostly unknown. The aim of this study was to investigate the role of PAR-1 as a mediator of BPH development.

METHODS

PAR-1 expression was investigated in BPH and normal prostate tissues by immunohistochemistry. Prostate stromal cells were isolated from BPH specimens, cultured and immunohistochemically characterized. Cultured stromal cells were stimulated with PAR-1 agonists, and extracellular-signal regulated kinase (ERK1/2) activation and cell proliferation were examined. PAR-1 mediated FGF-7 production by cultured stromal cells was assessed by RT-PCR and immunoassays, and verified by small interfering RNA (siRNA).

RESULTS

PAR-1 expression was increased in BPH stroma. In stromal cells isolated from BPH tissues, PAR-1 agonists activated ERK1/2 in a time- and concentration-dependent manner and with resultant enhanced cell proliferation. Pertussis toxin-sensitive G protein/(betagamma-subunits)-phosphatidylinositol 3-kinase and protein kinase C pathways were involved in ERK1/2 phosphorylation. PAR-1 activation strikingly induced FGF-7 production from cultured stromal cells mediated predominantly via ERK1/2 signaling pathway, and PAR-1 siRNA decreased the elicited FGF-7 upregulation.

CONCLUSIONS

The expression and function of PAR-1 in BPH stroma indicate PAR-1 may play important roles in BPH pathogenesis.

Elevated epithelial expression of interleukin-8 correlates with myofibroblast reactive stroma in benign prostatic hyperplasia

OBJECTIVES

Numerous inflammatory diseases display elevated interleukin (IL)-8, and most are associated with a reactive stroma. IL-8 expression is also elevated in benign prostatic hyperplasia (BPH), yet little is known about reactive stroma in BPH. Whether a reactive stroma response exists in BPH, whether this correlates with elevated IL-8, and whether IL-8 can induce a reactive stroma phenotype have not been determined. This study was designed to specifically address these issues.

METHODS

Normal prostate transition zone tissue and BPH specimens, as identified by the Baylor College of Medicine pathology department, were examined by quantitative immunohistochemistry to correlate IL-8, smooth muscle alpha-actin, vimentin, calponin, and tenascin-C. In addition, human prostate stromal cell cultures were used to evaluate the effect of IL-8 on the expression of reactive stroma biomarkers.

RESULTS

BPH nodules exhibited elevated epithelial IL-8 immunoreactivity, and this correlated with elevated smooth muscle alpha-actin, reduced calponin, and altered deposition of tenascin-C, relative to the normal prostate transition zone tissue (P <0.05). Multiple vimentin-positive prostate stromal fibroblast cultures were induced by IL-8 to also co-express smooth muscle alpha-actin and tenascin-C, typical of a reactive stroma myofibroblast phenotype.

CONCLUSIONS

These data show that BPH reactive stroma is fundamentally different from normal prostate fibromuscular stroma and is typified by the emergence of a reactive stroma myofibroblast phenotype. This reactive stroma pattern correlated spatially with IL-8 elevation in adjacent epithelium. Additionally, IL-8 induced expression of myofibroblast markers in human prostate fibroblasts in vitro. These results suggest that IL-8 acts as a regulator of BPH reactive stroma and is therefore a potential therapeutic target.

Association of interleukin-4 and interleukin-1 receptor antagonist gene polymorphisms and risk of benign prostatic hyperplasia

OBJECTIVES

The genetic and cellular processes involved in the etiopathology of benign prostatic hyperplasia (BPH) are unknown. Although evidence of BPH as an immune-mediated disease distinct from prostate cancer is growing, the cytokine gene polymorphisms associated with the risk of BPH have been explored less. The purpose of this study was to investigate the genetic association of polymorphisms of important cytokine genes (IL-4 and IL-1Ra) with the risk of BPH in a case-control study of a North Indian population.

METHODS

The IL-4 and IL-1Ra gene polymorphisms were genotyped with variable number of tandem repeats-polymerase chain reaction in 150 patients with BPH and normal healthy controls. On the basis of their response to combined therapy of alpha-adrenergic inhibitor plus 5-alpha-reductase inhibitor, patients were grouped as responders and nonresponders. The genotype distribution and allelic frequencies between the patients and controls were compared, and odds ratios with 95% confidence intervals were calculated using Statistical Package for Social Sciences software, version 11.5.

RESULTS

The difference in genotype frequency distribution for the IL-4 and IL-1Ra gene polymorphisms between the BPH and control groups were statistically significant (P <0.05). A significant difference (P <0.05) was also observed between the responder and nonresponder groups in the IL-4 gene variants.

CONCLUSIONS

IL-4 and IL-1Ra gene polymorphisms are associated with the risk of BPH. This study for the first time has demonstrated an association between the IL-4 polymorphism and BPH and particularly influences the therapeutic response of patients.

Cellular senescence and organismal aging

Cellular senescence, first observed and defined using in vitro cell culture studies, is an irreversible cell cycle arrest which can be triggered by a variety of factors. Emerging evidence suggests that cellular senescence acts as an in vivo tumor suppression mechanism by limiting aberrant proliferation. It has also been postulated that cellular senescence can occur independently of cancer and contribute to the physiological processes of normal organismal aging. Recent data have demonstrated the in vivo accumulation of senescent cells with advancing age. Some characteristics of senescent cells, such as the ability to modify their extracellular environment, could play a role in aging and age-related pathology. In this review, we examine current evidence that links cellular senescence and organismal aging.

Cellular signaling by fibroblast growth factors (FGFs) and their receptors (FGFRs) in male reproduction

The major function of the reproductive system is to ensure the survival of the species by passing on hereditary traits from one generation to the next. This is accomplished through the production of gametes and the generation of hormones that function in the maturation and regulation of the reproductive system. It is well established that normal development and function of the male reproductive system is mediated by endocrine and paracrine signaling pathways. Fibroblast growth factors (FGFs), their receptors (FGFRs), and signaling cascades have been implicated in a diverse range of cellular processes including: proliferation, apoptosis, cell survival, chemotaxis, cell adhesion, motility, and differentiation. The maintenance and regulation of correct FGF signaling is evident from human and mouse genetic studies which demonstrate that mutations leading to disruption of FGF signaling cause a variety of developmental disorders including dominant skeletal diseases, infertility, and cancer. Over the course of this review, we will provide evidence for differential expression of FGFs/FGFRs in the testis, male germ cells, the epididymis, the seminal vesicle, and the prostate. We will show that this signaling cascade has an important role in sperm development and maturation. Furthermore, we will demonstrate that FGF/FGFR signaling is essential for normal epididymal function and prostate development. To this end, we will provide evidence for the involvement of the FGF signaling system in the regulation and maintenance of the male reproductive system.

Inhibition of prostate growth and inflammation by the vitamin D receptor agonist BXL-628 (elocalcitol)

The prostate is a target organ of vitamin D receptor (VDR) agonists and represents an extra-renal site of 1,25-dihydroxyvitamin D(3) synthesis, but its capacity to respond to VDR agonists has, so far, been almost exclusively probed for the treatment of prostate cancer. We have analyzed the capacity of VDR agonists to treat benign prostatic hyperplasia (BPH), a complex syndrome characterized by a static component related to prostate overgrowth, a dynamic one responsible for urinary irritative symptoms, and an inflammatory component. Preclinical data demonstrate that VDR agonists, and notably BXL-628 (elocalcitol), reduce the static component of BPH by inhibiting the activity of intra-prostatic growth factors downstream of the androgen receptor, and the dynamic component by targeting bladder cells. In addition, BXL-628 inhibits production of proinflammatory cytokines and chemokines by human BPH cells. These data have led to a proof-of-concept clinical study that has successfully shown arrest of prostate growth in BPH patients treated with BXL-628, with excellent safety. We have documented the anti-inflammatory effects of BXL-628 also in animal models of autoimmune prostatitis, observing a significant reduction of intra-prostatic cell infiltrate following administration of this VDR agonist, at normocalcemic doses, in mice with already established disease. These data extend the potential use of VDR agonists to novel indications that represent important unmet medical needs, and provide a sound rationale for further clinical testing.

Is benign prostatic hyperplasia (BPH) an immune inflammatory disease?

OBJECTIVES

Chronic inflammation has been documented for years in benign prostatic hyperplasia (BPH), but only now has it become evident as a major factor in disease progression. This review highlights the immunologic key features of chronic inflammation in BPH and the present interpretation of these changes in the development and progression of BPH.

RESULTS

Almost all BPH specimens show inflammatory infiltrates at histologic examination, but correlation to bacterial or other foreign antigens has not been established. Recognition of prostate secretion products by autoreactive T cells and animal models on experimental prostatitis demonstrate an autoimmune component to chronic inflammation. The infiltrate consists predominantly of chronically activated CD4(+) T lymphocytes, which are permanently recruited to prostate tissue via elevated expression of interleukin 15 (IL-15) and interferon gamma (IFN-gamma), proinflammatory cytokines produced by smooth muscle and T cells, respectively. With the appearance of infiltrates, T cell-derived cytokine production of IFN-gamma, IL-2, and transforming growth factor beta increases, the former two ultimately reaching 10-fold and the latter 2-fold higher levels in fully developed BPH than in normal prostates. As "mature" BPH nodules develop, IL-4 and IL-13 expression increases >2-fold, corresponding to a T-helper (Th)0/Th2 cytokine pattern. Dysregulation of the immune response in BPH may occur via elevated expression of proinflammatory IL-17, which stimulates a multifold production of IL-6 and IL-8, key executors of stromal growth in BPH.

CONCLUSIONS

These data strongly suggest that BPH is an immune inflammatory disease. Unravelling the specific nature of immune dysregulation may help design novel drugs with these specific targets in mind.

Seminal plasma cytokines and chemokines in prostate inflammation: interleukin 8 as a predictive biomarker in chronic prostatitis/chronic pelvic pain syndrome and benign prostatic hyperplasia

OBJECTIVE

This prospective study quantified cytokine and chemokine levels in seminal plasma of patients with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) and benign prostatic hyperplasia (BPH), to evaluate inflammatory mediators as possible surrogate markers for diagnosis and treatment efficacy.

METHODS

Seminal plasma levels of eight cytokines and nine chemokines were evaluated by multiplex arrays in 83 men: 20 healthy controls and 9 men with CP/CPPS IIIA, 31 with CP/CPPS IIIB, and 23 with BPH. Prostate samples obtained by transurethral resection of the prostate from 13 patients with BPH were analysed by immunohistochemistry to detect interleukin 8 (IL-8)-producing cells and characterise inflammatory infiltrates.

RESULTS

Significantly increased levels of cytokines (IL-1alpha, IL-1beta, IL-6, IL-10, IL12p70) and chemokines (CCL1, CCL3, CCL4, CCL17, CCL22, CXCL8/IL-8) were observed in seminal plasmas from patients with CP/CPPS or BPH. However, only IL-8 was significantly elevated compared to controls (median [quartiles] 1984 [1164-2444] pg/ml), in patients with CP/CPPS IIIA (15,240 [10,630-19,501] pg/ml; p<0.0001), CP/CPPS IIIB (2983 [2033-5287] pg/ml; p=0.008), and BPH (5044 [3063-11,795] pg/ml, p<0.0001), discriminating CP/CPPS IIIA versus IIIB (accuracy=0.882+/-0.078; p=0.001). Inflammatory infiltrates were detected in prostate samples from 13 of 13 BPH patients, and IL-8-producing prostate cells in 11 of 13 samples. IL-8 concentration in seminal plasma was positively correlated with symptom score and prostate-specific antigen levels both in CP/CPPS and BPH patients.

CONCLUSIONS

IL-8 is expressed in situ by epithelial and stromal prostate cells and is functional, as shown by recruitment of cells expressing cognate receptors in BPH prostate tissue, indicating its involvement in disease pathogenesis. Among all the cytokines and chemokines analysed, IL-8 appears to be the most reliable and predictive surrogate marker to diagnose prostate inflammatory conditions, such as CP/CPPS and BPH.

Pre-clinical evidence and clinical translation of benign prostatic hyperplasia treatment by the vitamin D receptor agonist BXL-628 (Elocalcitol)

The active form of vitamin D, 1,25-dihydroxyvitamin D3, is a secosteroid hormone that binds to the vitamin D receptor (VDR), a member of the superfamily of nuclear receptors, and exerts a number of diverse biological functions. The natural hormone and synthetic VDR agonists are well known for their capacity to control calcium and bone metabolism, but they also regulate proliferation and differentiation of many cell types, and possess exquisite immunoregulatory properties, mostly by targeting dendritic cells (DC) and T cells. These properties have been clinically exploited in the treatment of different diseases, from secondary hyperparathyroidism to osteoporosis to psoriasis. The VDR is expressed by most cell types, including cells of the urogenital system such as prostate and bladder cells. In particular, the prostate has been recognized as a target organ of VDR agonists and represents an extra-renal synthesis site of 1,25-dihydroxyvitamin D3, but its capacity to respond to VDR agonists has, so far, been probed only for the treatment of prostate cancer. We have taken a different approach, and have analysed the capacity of VDR agonists to treat benign prostatic hyperplasia (BPH), a complex syndrome characterized by a static component related to prostate overgrowth, a dynamic component responsible for urinary irritative symptoms, and a possible inflammatory component. Pre-clinical data reviewed here demonstrate that VDR agonists, and notably BXL-628 (Elocalcitol), reduce the static component of BPH by inhibiting the activity of intra-prostatic growth factors downstream of the androgen receptor, and the dynamic component by targeting bladder cells. These data have led to a proof-of-concept clinical study that has successfully shown arrest of prostate growth in BPH patients treated with BXL-628. Ongoing clinical studies will assess the capacity of this VDR agonist to reduce symptoms and ameliorate flow parameters in BPH-affected individuals. The pronounced effects of BXL-628 on bladder smooth muscle cells and its anti-inflammatory properties indeed anticipate beneficial effects also on BPH-related lower urinary tract symptoms.

Expression of bFGF/FGFR-1 and vascular proliferation related to clinicopathologic features and tumor progress in localized prostate cancer

Microvessel density (MVD) has been associated with progression of prostate cancer. Although basic fibroblast growth factor (bFGF) is a known endothelial mitogen, the prognostic role of bFGF and its receptor FGFR-1 in prostate cancer has been controversial. The aim of our study was to examine the tissue distribution and prognostic significance of bFGF, FGFR-1, and microvascular proliferation. Sections from 104 radical prostatectomy specimens were examined by factor VIII/Ki-67 staining for proliferating capillary index (PCI) and MVD, and tissue microarray sections were immunostained for bFGF and FGFR-1. Increased PCI (median 0.49%) was related to strong stromal expression of bFGF (P=0.003) but was without prognostic impact. Strong bFGF staining was associated with well-differentiated tumors, no capsular penetration, low serum-prostate-specific antigen (s-PSA), low tumor cell proliferation, and increased time to biochemical failure (P=0.007), and was of independent prognostic importance in multivariate survival analysis. bFGF expression in vessels was associated with low MVD (P=0.0003). In contrast, strong tumor cell FGFR-1 expression was related to high preoperative s-PSA. Thus, increased stromal and vessel bFGF was associated with less aggressive tumors. Our findings indicate a complex relationship between bFGF/FGFR-1 expression and prognosis of prostate cancer. Vascular proliferation revealed no prognostic impact in this study.

Vitamin D-induced up-regulation of tumour necrosis factor alpha (TNF-alpha) in prostate cancer cells

1alpha,25-dihydroxyvitamin D3 (1alpha,25(OH)2D3 or calcitriol) is an active hormone that regulates cellular proliferation and induces apoptosis in cancer cells. Here we report on a new calcitriol target gene in prostate cancer cells, tumour necrosis factor alpha (TNF-alpha). Calcitriol and its analogue CB1093 up-regulate TNF-alpha mRNA expression in LNCaP and PC-3 cells. The stimulation is dose-dependent in both of these cell lines, demonstrated by the quantitative real-time polymerase chain reaction. Calcitriol and CB1093 act synergistically with human recombinant TNF-alpha in activation of TNF-alpha mRNA expression in LNCaP but not in PC-3 cells. Transcriptional activation of TNF-alpha gene by calcitriol or CB1093 does not lead to TNF-alpha protein secretion, however calcitriol and CB1093 enhance TPA-stimulated TNF-alpha production in LNCaP cells. We did not observe any significant effect of calcitriol on regulation of TNFR1 at the level of gene expression. Nor does calcitriol affect transcriptional regulation of cytokine (IL-1, IL-6) and cytokine receptor genes in LNCaP and PC-3 prostate cancer cell lines. Calcitriol and its analogue CB1093 at 10 nM concentration induce programmed cell death in LNCaP cells. Combined addition of human recombinant TNF-alpha with calcitriol or CB1093 cause enhanced effect in induction of apoptosis. We conclude that under physiological conditions vitamin D activates only the transcription of TNF-alpha gene, for TNF-alpha protein synthesis additional cofactors are required. Therefore a cooperation of vitamin D and TNF-alpha may play an important role in the control of cell growth in prostate cancer.