Zonal variation of apoptosis and proliferation in the normal prostate and in benign prostatic hyperplasia

Apparent differences in prostate zones: susceptibility to prostate cancer, benign prostatic hyperplasia and prostatitis

Men are inevitably plagued by prostate disease throughout their lives. However, the understanding of the pathogenesis of prostate diseases is still limited. In the 1960s, McNeal proposed the theory of prostate zones: the prostate was divided into three main zones: transition zone, central zone, and peripheral zone. Over the past 50 years, significant differences between different prostate zones have been gradually revealed. We summarized the most significant differences in different zones of the prostate. For the first time, we proposed the "apparent difference in prostate zones" concept. This new concept has been proposed to understand the different zones of the prostate better. It also provided new ideas for exploring the susceptibility of lesions in different prostate zones. Despite the reported differences between zones, the treatment of prostate-related diseases remains partition agnostic. Therefore, we also discussed the clinical significance of the "apparent difference in the prostate zone" and emphasized the necessity of prostate zones.

Single-cell RNA sequencing of human prostate basal epithelial cells reveals zone-specific cellular populations and gene expression signatures

Despite evidence of genetic signatures in normal tissue correlating with disease risk, prospectively identifying genetic drivers and cell types that underlie subsequent pathologies has historically been challenging. The human prostate is an ideal model to investigate this phenomenon because it is anatomically segregated into three glandular zones (central, peripheral, and transition) that develop differential pathologies: prostate cancer in the peripheral zone (PZ) and benign prostatic hyperplasia (BPH) in the transition zone (TZ), with the central zone (CZ) rarely developing disease. More specifically, prostatic basal cells have been implicated in differentiation and proliferation during prostate development and regeneration; however, the contribution of zonal variation and the critical role of basal cells in prostatic disease etiology are not well understood. Using single-cell RNA sequencing of primary prostate epithelial cultures, we elucidated organ-specific, zone-specific, and cluster-specific gene expression differences in basal cells isolated from human prostate and seminal vesicle (SV). Aggregated analysis identified ten distinct basal clusters by Uniform Manifold Approximation and Projection. Organ specificity compared gene expression in SV with the prostate. As expected, SV cells were distinct from prostate cells by clustering, gene expression, and pathway analysis. For prostate zone specificity, we identified two CZ-specific clusters, while the TZ and PZ populations clustered together. Despite these similarities, differential gene expression was identified between PZ and TZ samples that correlated with gene expression profiles in prostate cancer and BPH, respectively. Zone-specific profiles and cell type-specific markers were validated using immunostaining and bioinformatic analyses of publicly available RNA-seq datasets. Understanding the baseline differences at the organ, zonal, and cellular level provides important insight into the potential drivers of prostatic disease and guides the investigation of novel preventive or curative treatments. Importantly, this study identifies multiple prostate basal cell populations and cell type-specific gene signatures within prostate basal epithelial cells that have potential critical roles in driving prostatic diseases. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Differential gene expression of BCL-2, ZEB2-AS1 and BALR-2 in prostate cancer and benign prostatic hyperplasia

Prostate cancer (PCa) and benign prostate hyperplasia (BPH) are highly prevalent heterogeneous disorders among men. Whereas PCa and BPH underline common pathological features, apoptotic-related genes might be differentially expressed in these diseases. This study was aimed at testing BCL-2 as well as BALR-2 and ZEB2-AS1 apoptosis-related long non-coding RNA (lncRNA) in patients with PCa and BPH. The expression levels of the BCL-2 gene and ZEB2-AS1 lncRNA were upregulated in tumoural tissues in comparison to adjacent non-cancerous tissues (ANCTs) and BPH tissues. In contrast, the expression level of BALR-2 lncRNA was significantly higher in BPH compared with tumoural tissues. Furthermore, while no association was noticed between the relative expression of ZEB2-AS1 and the tumour grade, the relative expression of BCL-2 and BALR-2 is strongly associated with a higher grade of the tumour in PCa samples compared with the ANCTs. The receiver operating characteristic (ROC) curve analysis indicated the highest specificity and diagnostic value in distinguishing PCa and ANCTs as well as PCa and BPH, respectively. In conclusion, altered expression of BCL-2 and BALR-2 was observed to be associated with tumoural progression and could be used as potential candidates for distinguishing PCa tissues from ANCTs or BPH samples.

Resveratrol Attenuates the Proliferation of Prostatic Stromal Cells in Benign Prostatic Hyperplasia by Regulating Cell Cycle Progression, Apoptosis, Signaling Pathways, BPH Markers, and NF- κB Activity

Resveratrol can inhibit cell proliferation and metastasis and induce apoptosis. However, the mechanisms of action through which resveratrol inhibits the abnormal proliferation of prostate stromal cells, causing prostatic hyperplasia, have not been fully elucidated. Here, we evaluated the inhibitory effects of resveratrol on cell proliferation associated with prostatic hyperplasia using WPMY-1 cells. Our results showed that resveratrol inhibited the proliferation of WPMY-1 cells via the induction of G₀/G₁-phase cell cycle arrest, which was caused by downregulated expression of cyclins and cyclin-dependent kinases regulated by increased p21WAF1 and p27KIP1 expression level. In addition, resveratrol treatment suppressed the phosphorylation of phosphatidylinositol 3-kinase/AKT and extracellular signal-regulated kinase 1/2. The expression levels of molecular markers affecting prostate development were also reduced by treatment with resveratrol. Finally, resveratrol attenuated the binding activity of the transcription factor nuclear factor-κB in WPMY-1 cells, and accelerated apoptotic cell death via intrinsic cascade pathway. These results indicate that resveratrol may be useful for the prevention or treatment of prostatic hyperplasia.

Identification and functional activity of matrix-remodeling associated 5 (MXRA5) in benign hyperplastic prostate

Objective: Benign prostatic hyperplasia (BPH) is a common condition in aging males. The current study aims to identify differentially expressed genes (DEGs) associated with BPH and to elucidate the role of matrix-remodeling associated 5 (MXRA5) protein and mitogen-activated protein kinase (MAPK) signaling pathways in BPH.

Results: A total of 198 DEGs and a number of related pathways were identified with MXRA5 being one of the most significantly altered DEGs. MXRA5 was upregulated in BPH samples and localized mostly in stroma. Knockdown of MXRA5 induced stromal cell cycle arrest instead of inhibiting apoptosis. Consistently, MXRA5 overexpression enhanced epithelial cell proliferation. In addition, phosphorylated ERK1/2 and p38, key members of the MAPK family, were strongly decreased with knockdown but increased with overexpression.

Conclusion: Our novel data demonstrates that upregulation of MXRA5 in the enlarged prostate could contribute to the development of BPH through increasing cell proliferation via the MAPK pathway. Thus, the MXRA5-MAPK system could be rediscovered as a new therapeutic target for treating BPH.

Methods: Microarray analysis and integrated bioinformatics were conducted. The expression and biologic functions of MXRA5 was investigated via RT-PCR, western-blot, immunofluorescence, flow cytometry and MTT assay. Finally, genes involved in regulation of the MAPK pathway were investigated.

The relationship between anogenital distance and benign prostate hyperplasia-related lower urinary tract symptoms

Anogenital distance (AGD) is the length between the genitals and anus which shows an androgenic activity in the evolution of the reproductive system in the uterine life. For prostatic evolution and development during the embryological stage, androgen exposure is required. In this study, we aimed to investigate the relationship between AGD and benign prostate hyperplasia (BPH)-related lower urinary tract symptoms (LUTS). A total of 70 patients who were admitted to our urology clinics with LUTS due to BPH (LUTS group) and 70 patients without LUTS (control group) were included. All patients were administered an International Prostate Symptom Score form. Data including height, weight, body mass index, total prostate-specific antigen, prostate volume and uroflowmetry Qmax values of all patients were evaluated. The AGD of the LUTS and control groups was measured. The mean AGD^AS values of the LUTS group were significantly lower than the control group (p = .013). There was no statistically significant difference between the two groups in terms of the mean adjusted AGD^AP values (p = .241). However, the mean adjusted AGD^AS values were significantly lower in the LUTS group than the control group (p = .002). Our study results suggest that AGD may be a useful marker in BPH-related LUTS.

Chinese Skullcap (Scutellaria baicalensis Georgi) inhibits inflammation and proliferation on benign prostatic hyperplasia in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Chinese Skullcap (Scutellaria baicalensis Georgi), which is part of the 50 fundamental herbs of Traditional Chinese Medicine, has been extensively used in the several East Asian countries to treat pyrexia, micturition disorder and inflammation. Although skullcap has effective properties on various diseases, the effects and molecular mechanism of Chinese Skullcap on BPH are still needed for better understanding.

AIM OF THE STUDY

In present study, we aimed to demonstrate the efficacy of Chinese Skullcap root extract (SRE) in testosterone-induced BPH rats and investigate the exact regulatory mechanism involved.

MATERIALS AND METHODS

We followed a protocol of testosterone-induced BPH. Rats were allocated into five groups: Group 1, control; Group 2, BPH-induced rats; Group 3, BPH-induced rats administrated with finasteride; Group 4, BPH-induced rats administrated with SRE 100 mg/kg/day; Group 5 - BPH-induced rats administrated with SRE 200 mg/kg/day. We measured the weight of prostate, and thickness of prostate using H&E staining. Western blotting, immunostaining and real-time PCR were used to measure proliferation- and inflammation-relative markers. To confirm the effects of SRE on apoptotic events in BPH-induced tissues, we performed the TUNEL assay.

RESULTS

Compared with the untreated group, the SRE administration group suppressed pathological alterations, such as prostate growth and increase in serum DHT and 5α-reductase levels. Furthermore, SRE significantly obliterated the expression of AR and PCNA. SRE also restored Bax/Bcl-2 balance, inducing apoptosis in rats with BPH. These effect of SRE was more prevalent than commercial 5α-reductase inhibitor, finasteride.

CONCLUSIONS

Taken together, we propose that SRE suppresses abnormal androgen events in prostate tissue and inhibits the development of BPH by targeting inflammation- and apoptosis-related markers. These finding strengthens that SRE could be used as plant-based 5α-reductase inhibitory alternative.

Spatially Restricted Stromal Wnt Signaling Restrains Prostate Epithelial Progenitor Growth through Direct and Indirect Mechanisms

Cell-autonomous Wnt signaling has well-characterized functions in controlling stem cell activity, including in the prostate. While niche cells secrete Wnt ligands, the effects of Wnt signaling in niche cells per se are less understood. Here, we show that stromal cells in the proximal prostatic duct near the urethra, a mouse prostate stem cell niche, not only produce multiple Wnt ligands but also exhibit strong Wnt/β-catenin activity. The non-canonical Wnt ligand Wnt5a, secreted by proximal stromal cells, directly inhibits proliefration of prostate epithelial stem or progenitor cells whereas stromal cell-autonomous canonical Wnt/β-catenin signaling indirectly suppresses prostate stem or progenitor activity via the transforming growth factor β (TGFβ) pathway. Collectively, these pathways restrain the proliferative potential of epithelial cells in the proximal prostatic ducts. Human prostate likewise exhibits spatially restricted distribution of stromal Wnt/β-catenin activity, suggesting a conserved mechanism for tissue patterning. Thus, this study shows how distinct stromal signaling mechanisms within the prostate cooperate to regulate tissue homeostasis.

Elevated expression of HIF-lα in actively growing prostate tissues is associated with clinical features of benign prostatic hyperplasia

Background

Benign prostatic hyperplasia (BPH) is one of the most common diseases in middle-age or older men. Increasing evidence has shown that BPH is associated with hypoxia microenvironment.

Methods

We retrospectively collected patient data and tissue samples from fetal prostates(FP), normal prostates(NP), intra-acinar of BPH, peri-acinar of BPH, prostate cancers and sarcomas of prostate. The expression of HIF-1α, as well as VEGF was visualized by immunohistochemistry and statistically analyzed with clinical parameters.

Results

Expression of HIF-lα was observed in intra-acinar of BPH (69.5%), prostate cancer (85.7%) and all FPs, while NP and peri-acinar of BPH tissues were all stained negative. HIF-lα levels in FPs and the malignant tumors were higher than BPH tissues(p < 0.05), and the expression of HIF-lα in intra-acinar of BPH was higher than NP and peri-acinar of BPH (p < 0.05). The expression of HIF-lα was correlated with the weight of intra-acinar of prostate (p < 0.05). And patients with prostate weight larger that 72.45g were prone to have HIF-lα moderate-positive expression, according to the ROC curve (AUC = 0.734, 95%CI = 0.630-0.838). Moreover, the risk of acute urine retention (AUR) for HIF-lα moderate-positive patients increased significantly (OR=5.517, 95%CI = 2.434-12.504).

Conclusions

HIF-lα expression is increased in highly proliferative prostate tissues and correlated with the weight of intra-acinar prostate. Moreover, HIF-lα is also an independent risk factor for AUR occurrence in BPH patients.

Caspase-3 expression in normal oral epithelium, oral submucous fibrosis and oral squamous cell carcinoma

Context:

The epithelium atrophy, as the oral submucous fibrosis (OSMF) progresses, is believed to be an after effect of stromal fibrosis, hyalinization, decrease in vascularity and cellularity and is considered as “ischemic atrophy.” Due to hypoxia, caspase-3 get activation and subsequent decrease in viable cell count can occur.

Aims and Objectives:

To determine caspase-3 expression in various grades of OSMF and oral squamous cell carcinoma (OSCC) to find out whether upregulation of apoptosis is responsible for the epithelial changes in OSMF.

Subjects and Methods:

The control tissue (15 samples from normal oral mucosa) and study group comprising 97 cases of OSMF of different grades and OSCC associated with OSMF were stained with caspase-3 antibody, and the percentage of positive cells was calculated using ImageJ software.

Statistical Analysis:

The results obtained were statistically analyzed using ANOVA and Tukey's honest significance difference test and Mann–Whitney U-test.

Results:

There was a nuclear expression of caspase-3 in basal and parabasal layers of normal epithelium. There was cytoplasmic expression of caspase-3 in OSMF without dysplasia, total absence of caspase-3 expression in dysplastic epithelium and in majority cases of OSCC. The caspase-3 percentage was increased in OSMF (0%–53%) when compared with OSCC (0%–8%). The statistical comparison of caspase-3 among normal, OSMF and OSCC patients revealed significant correlation (P < 0.00010). The comparison within different grades of OSMF and between dysplastic and nondysplastic epithelium OSMF also showed significance (P < 0.019).

Conclusions:

The decreased expression of caspase-3 in disease progression reflects its role in the malignant transformation.

An introduction to acinar pressures in BPH and prostate cancer

Intra-acinar and peri-acinar pressures in the prostate might be key factors in the evolution of its zonal morphology and the pathogenesis of BPH and cancer. Herein, I hypothesize that intra-acinar pressures lead to a decrease in apoptosis by distending or stretching acinar epithelium and its surrounding stroma. Increased prostatic smooth muscle content and tone might generate peri-acinar pressures, which could, in the long-term, counteract intra-acinar pressures and decrease epithelial stretch. Thus, it is proposed that BPH (characterized by increased prostatic smooth muscle and, therefore, raised peri-acinar pressures) might decrease the risk of prostate cancer progression by counteracting intra-acinar pressures. In the context of this theory, the transition zone might have evolved as a specialized region within the prostate that can mount a concerted stromal-epithelial response to increased urethral and intra-acinar pressures (BPH), and the urethral angulation, anterior stroma and the prostatic capsule have an adjunctive evolutionary role in this phenomenon.

Chronic caffeine intake increases androgenic stimuli, epithelial cell proliferation and hyperplasia in rat ventral prostate

Coffee intake has been associated with a low risk of developing cancer, including prostate cancer, which is one of the most commonly diagnosed cancer in men. However, few studies have evaluated the chronic effects of caffeine, which is the most abundant methylxanthine in coffee, on prostate morphology and physiology. In the present study, we investigated the effects of chronic, low-dose caffeine intake on rat prostate morphology from puberty to adulthood. Five-week-old male Wistar rats were randomized into two experimental groups: caffeine-treated (20 ppm in drinking water, n = 12) and control (n = 12). The ventral and dorsolateral prostates were dissected, weighted and submitted to morphological, morphometrical and immunohistochemical analysis of cellular proliferation, apoptosis and androgen receptor (AR) tissue expression. The testosterone (T) and dihydrotestosterone (DHT) concentrations were measured in the plasma. Our results show that caffeine intake increased the concentrations of T and DHT, organ weight, epithelial cell proliferation and AR tissue expression in the ventral prostatic lobe. All the ventral prostates from the caffeine-treated animals presented various degrees of epithelial and stromal hyperplasia. Our results suggest that chronic caffeine intake from puberty increases androgenic signalling and cell proliferation in the rat prostate gland and can be related to the development of benign prostatic hyperplasia.

Chemokines and BPH/LUTS

A wealth of published studies indicate that a variety of chemokines are actively secreted by the prostatic microenvironment consequent to disruptions in normal tissue homeostasis due to the aging process or inflammatory responses. The accumulation of senescent stromal fibroblasts, and, possibly, epithelial cells, may serve as potential driving forces behind chemokine secretion in the aging and enlarged human prostate. Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) and histological inflammation may also potentially serve as rich sources of chemokine secretion in the prostate. Once bound to their cognate receptors, chemokines can stimulate powerful pro-proliferation signal transduction pathways and thus function as potent growth factors in the development and progression of Benign Prostatic Hyperplasia (BPH) and lower urinary tract symptoms (LUTS). These functions have been amply demonstrated experimentally and particularly point to robust Mitogen Activated Protein Kinase (MAPK) and phosphoinositide 3-kinase (PI3K) signaling, as well as global transcriptional responses, which mediate chemokine-stimulated cellular proliferative responses. A small body of literature also suggests that chemokine-mediated angiogenesis may comprise a contributing factor to BPH/LUTS development and progression. Thus, the observed low-level secretion of multiple chemokines within the aging prostatic microenvironment may promote a concomitant low-level, but cumulative, over-proliferation of both stromal fibroblastic and epithelial cell types associated with increased prostatic volume. Though the accumulated evidence is far from complete and suffers from some rather extensive gaps in knowledge, it argues favorably for the conclusion that chemokines can, and likely do, promote prostatic enlargement and the associated lower urinary tract symptoms, and justifies further investigations examining chemokines as potential therapeutic targets to delay or ablate BPH/LUTS initiation and progression.

Seasonal changes in morphology and steroid receptor expression in the prostate of the brushtail possum (Trichosurus vulpecula): an animal model for the study of prostate growth?

The prostate of the brushtail possum undergoes growth and regression during the year. The present study investigated the morphological changes and expression of androgen and oestrogen receptors during the breeding and non-breeding seasons. Prostate tissue was collected from adult possums at 2-monthly intervals. The periurethral and outer glandular areas were separated and the volume of stromal, epithelial and luminal tissues measured in each area. Immunohistochemistry was used to investigate cell proliferation with proliferating cell nuclear antigen (PCNA) and to localise androgen receptor (AR) and oestrogen receptors α and β (ERα, ERβ). Seasonal changes in expression of the three receptors were investigated using quantitative PCR and western blot analysis. During the breeding season the volume of stromal tissue in the periurethral area and the luminal volume in the glandular area significantly increased. The change in periurethral volume was associated with increased PCNA-immunopositive cells. While the localisation of AR to the stromal and epithelial cells did not change, there was a significant increase in receptor expression before the main breeding season. ERα and ERβ expression and localisation did not alter during the year. Similarities in receptor expression and localisation suggest that the possum may be a suitable animal model for the study of human prostate growth.

Differential response to zinc-induced apoptosis in benign prostate hyperplasia and prostate cancer cells

Zinc concentrations in the prostate are uniquely high but are dramatically decreased with prostate cancer. Studies have suggested that increasing zinc in the prostate may be a potential therapeutic strategy. The goal of this study was to evaluate the antiproliferative effects of zinc in prostate cancer cells (PC-3) and noncancerous benign prostate hyperplasia (BPH) cells (BPH-1) and to define possible mechanisms. PC-3 and BPH-1 cells were treated with zinc (0-250 microM) for 24 and 48 h, and cell growth and viability were examined. Apoptosis was assessed by phosphatidylserine externalization, caspase activation and protein expression of B-cell CLL/lymphoma 2 (Bcl-2)-associated X protein (BAX):Bcl-2. BPH-1 cells were more sensitive to the antiproliferative effects of zinc compared to PC-3. The response to zinc in PC-3 and BPH-1 cells differed as evidenced by opposing effects on Bcl-2:BAX expression. Additionally, different effects on the nuclear expression and activity of the p65 subunit of nuclear factor kappa B were observed in response to zinc between the two cell types. The differential response to zinc in PC-3 and BPH-1 cells suggests that zinc may serve an important role in regulating cell growth and apoptosis in prostate cancer and hyperplasia cells.

Pharmacological effects of saw palmetto extract in the lower urinary tract

Saw palmetto extract (SPE), an extract from the ripe berries of the American dwarf palm, has been widely used as a therapeutic remedy for urinary dysfunction due to benign prostatic hyperplasia (BPH) in Europe. Numerous mechanisms of action have been proposed for SPE, including the inhibition of 5alpha-reductase. Today, alpha(1)-adrenoceptor antagonists and muscarinic cholinoceptor antagonists are commonly used in the treatment of men with voiding symptoms secondary to BPH. The improvement of voiding symptoms in patients taking SPE may arise from its binding to pharmacologically relevant receptors in the lower urinary tract, such as alpha(1)-adrenoceptors, muscarinic cholinoceptors, 1,4-dihyropyridine receptors and vanilloid receptors. Furthermore, oral administration of SPE has been shown to attenuate the up-regulation of alpha(1)-adrenoceptors in the rat prostate induced by testosterone. Thus, SPE at clinically relevant doses may exert a direct effect on the pharmacological receptors in the lower urinary tract, thereby improving urinary dysfunction in patients with BPH and an overactive bladder. SPE does not have interactions with co-administered drugs or serious adverse events in blood biochemical parameters, suggestive of its relative safety, even with long-term intake. Clinical trials (placebo-controlled and active-controlled trials) of SPE conducted in men with BPH were also reviewed. This review should contribute to the understanding of the pharmacological effects of SPE in the treatment of patients with BPH and associated lower urinary tract symptoms (LUTS).

Primary prostatic central zone adenocarcinoma

The central zone (CZ) of the prostate is embryologically, anatomically, and histologically distinct. High-grade prostatic intraepithelial neoplasia (HGPIN) and prostatic adenocarcinoma (PAC) are encountered in the CZ, but have not been well studied. Non-CZ PAC that spread into the CZ can mimic CZ PAC. We reviewed 300 consecutive radical prostatectomies performed for PAC to identify cases showing PAC and HGPIN in the CZ. There were nine PAC (3%) localized predominantly in the CZ, presenting as a single tumor nodule (8/9) and associated with 4.5+/-1.1 foci HGPIN in the CZ and with only 1.7+/-0.5 foci in the PZ. Of the 291 non-CZ PAC, 24 cases showed satellite tumor nodules in the CZ, and 92 cases demonstrated secondary contiguous spread to the CZ. As compared to the non-CZ PAC, CZ PAC tended to have lower tumor volume, but had higher Gleason scores (8.10+/-0.6 vs. 6.30+/-0.7, p<0.05), as well as a higher incidence of a ductal carcinoma component (6/9), higher rates of capsular penetration, positive resection margins (4/9), and seminal vesicle spread (2/9). The CZ HGPIN associated with CZ PAC demonstrated cells with prominent nucleoli and formed either slender papillary structures or cribriform/solid patterns. The correlating positive biopsy cores were from the mid portion or from base of prostate and contained foci of HGPIN in 4/7 cases. The CZ PAC is characteristically accompanied by more foci of HGPIN in the CZ than in non-CZ and is associated with high grade and high stage. Preoperative diagnosis of CZ PAC can be suspected due to the histopathological features in the biopsy and is important to improve the free surgical resection rate.

LNCaP prostate cancer cells are insensitive to zinc-induced senescence

Prostate cancer is an age-related disease that is linked to the inability of prostate cells to accumulate zinc following transformation. It is shown in the present study that the basal percentage of normal prostate cells expressing senescence-associated beta-galactosidase (SA-beta-gal) is higher than that of the cancer cells. In the presence of high zinc in the cell culture medium, the percentage of normal prostate cells expressing the SA-beta-gal increased but not that of the cancer cells. Increased intracellular zinc occurs in the prostate cancer cells treated with supraphysiologic concentration of zinc but it does not induce senescence or decrease the telomerase activities in these cells. Senescence, however, occurred when the prostate cancer cells DNA is damaged by irradiation. These findings suggest that prostate cancer cells are insensitive to the senescence-inducing effects of zinc but the cancer cells retain the capacity to undergo senescence through other pathways.

Evaluation of AIbZIP and Cdc47 as markers for human prostatic diseases

OBJECTIVES

Benign prostatic hyperplasia and prostate cancer are important public health issues. However, histologic markers for these diseases are limited.

METHODS

Immunocytochemistry was used to analyze the cellular localization of AIbZIP, Cdc47, androgen receptor and estrogen receptor-beta markers. AIbZIP is a protein recently found to be more abundant in prostate cancer than in benign prostatic tissue, and Cdc47 is a cell proliferation-associated protein. The localization and modulation of androgen receptor and estrogen receptor-beta through the carcinogenesis process have been examined in several studies but controversial results were obtained. These four proteins were evaluated as potential markers of prostatic diseases in 210 needle core biopsies, including normal prostate, benign prostatic hyperplasia, low-grade and high-grade prostatic intraepithelial neoplasia, and different Gleason grades of prostatic adenocarcinoma.

RESULTS

Androgen receptor and estrogen receptor-beta do not discriminate between benign and malignant specimens, while AIbZIP was able to distinguish between them. Cdc47, in contrast, discriminated not only between malignant and benign prostatic tissue, but also between benign prostatic hyperplasia and normal prostatic tissue.

CONCLUSIONS

Cdc47 appears to be a sensitive marker of prostatic diseases since its expression gradually increased in parallel with the severity of the lesion. AIbZIP discriminated between benign tissue and cancer. AIbZIP and Cdc47 thus appear to be useful markers with diagnostic and prognostic values.

Apoptosis profiles in benign prostatic hyperplasia: close associations of cell kinetics with percent area density of histologic composition

OBJECTIVES

To investigate the possible correlations of apoptosis and apoptosis-associated factors, including the apoptotic index (AI), proliferation index (PI), and expression of Bcl-2 and caspase 3, with the percent area density of epithelium and stroma in benign prostatic hyperplasia (BPH).

METHODS

A total of 60 patients with histologically determined BPH were investigated. The percent area density of epithelium and stroma was determined using a computerized image analysis system after Masson's trichrome staining. Apoptosis was detected using the AI through the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling assay. Cell proliferation was determined using the PI through Ki-67 immunostaining. The expression of Bcl-2 and caspase 3 was immunohistochemically examined. Double-label immunofluorescent staining was performed to assess co-localization of Bcl-2 and caspase 3.

RESULTS

The stroma/epithelium ratio ranged from 4.6 to 6.3 (average 5.2) in BPH. A greater stromal PI was closely related to the percent area density of stroma (P <0.01), and a greater epithelial AI was reversely related to the percent area density of the epithelium (P <0.05). Bcl-2 and caspase 3 expression was detected in 50 (80%) and 48 (75%) of 60 BPH samples, respectively. The expression of Bcl-2 and caspase 3 was not related to PI, AI, or the percent area density of the BPH components (P >0.05). Immunofluorescence analysis revealed co-localization of Bcl-2 and caspase 3 in the serial sections of BPH specimens that already showed either Bcl-2 or caspase 3 expression.

CONCLUSIONS

The development of BPH may be associated with both stromal growth due to active stromal cell proliferation and epithelial growth due to reduced glandular apoptosis.

CXCL12 overexpression and secretion by aging fibroblasts enhance human prostate epithelial proliferation in vitro

The direct relationship between the aging process and the incidence and prevalence of both benign prostatic hyperplasia (BPH) and prostate cancer (PCa) implies that certain risk factors associated with the development of both diseases increase with the aging process. In particular, both diseases share an overly proliferative phenotype, suggesting that mechanisms that normally act to suppress cellular proliferation are disrupted or rendered dysfunctional as a consequence of the aging process. We propose that one such mechanism involves changes in the prostate microenvironment, which 'evolves' during the aging process and disrupts paracrine interactions between epithelial and associated stromal fibroblasts. We show that stromal fibroblasts isolated from the prostates of men 63-81 years of age at the time of surgery express and secrete higher levels of the CXCL12 chemokine compared with those isolated from younger men, and stimulate CXCR4-mediated signaling pathways that induce cellular proliferation. These studies represent an important first step towards a mechanistic elucidation of the role of aging in the etiology of benign and malignant prostatic diseases.

Expression of survivin and apoptotic biomarkers in benign prostatic hyperplasia

PURPOSE

We assessed the differential expression of survivin and other apoptotic markers in stromal and epithelial compartments of benign prostatic hyperplasia (BPH) and normal prostate tissue.

MATERIALS AND METHODS

Immunohistochemical staining for survivin, and transforming growth factor-beta1 and its receptors was done in normal prostate and BPH areas from 114 consecutive patients who underwent radical prostatectomy. Moreover, staining for survivin, Bcl-2, Bax, caspase-3 and Ki-67 was performed in prostate specimens from 23 consecutive patients who underwent open prostatectomy and 4 young patients who underwent cystoprostatectomy and had a normal prostate.

RESULTS

Survivin and Bcl-2 expression increased incrementally from normal prostate to epithelial BPH to stromal BPH. Caspase-3 expression was higher in BPH epithelium than in BPH stroma, which in turn was higher than that in normal prostate. Ki-67 was significantly over expressed in BPH stroma and epithelium. Survivin expression in BPH tissue correlated with International Prostate Symptom Score, quality of life, post-void residual urine volume, maximum urine flow rate and transforming growth factor-beta1 expression.

CONCLUSIONS

Survivin is over expressed in BPH and it correlates with BPH parameters. Increases in proliferation and inhibition of apoptosis have a role in BPH.

Number and location of nucleoli and presence of apoptotic bodies in diagnostically challenging cases of prostate adenocarcinoma on needle biopsy

There is limited published data regarding the significance of the number or position of nucleoli and the presence of apoptotic bodies in diagnostically challenging cases of adenocarcinoma of the prostate on needle biopsy material. One hundred consecutive prostate cancers on needle biopsy were sent because of diagnostic difficulty to an expert in urological pathology, and the remaining normal benign prostatic glands on the same core were evaluated for the number and location of nucleoli and for the presence of mitotic figures and apoptotic bodies. The Gleason scores of the cases were 6 (86%), 7 (9%), and 8 to 10 (5%). For comparison, the same parameters were evaluated in mimickers of cancer on needle biopsy from other cases, including partial atrophy (n = 135), fully developed atrophy (n = 89), adenosis (n = 50), prostate glands with acute inflammation (n = 50), and high-grade prostatic intraepithelial neoplasia (n = 100). Findings were recorded under high dry magnification (x40) using hematoxylin and eosin-stained sections. Although the number and position of nucleoli did not discriminate between cancer and benign mimickers, mitotic figures and apoptotic bodies were more commonly seen in cancer. Apoptotic bodies in particular were seen fairly frequently (34%) in prostatic adenocarcinoma (also seen in 13% of high-grade prostatic intraepithelial neoplasia), yet rarely in benign mimickers on needle biopsy. Our findings indicate that the presence of apoptotic bodies should be added to the list of histological features that are helpful in the diagnosis of challenging cases of prostate cancer on needle biopsy.

Sca-1 expression identifies stem cells in the proximal region of prostatic ducts with high capacity to reconstitute prostatic tissue

We previously showed that prostatic stem cells are concentrated in the proximal regions of prostatic ducts. We now report that these stem cells can be purified from isolated proximal duct regions by virtue of their high expression of the cell surface protein stem cell antigen 1 (Sca-1). In an in vivo prostate reconstitution assay, the purified Sca-1-expressing cell population isolated from the proximal region of ducts was more effective in generating prostatic tissue than a comparable population of Sca-1-depleted cells (203.0 +/- 83.1 mg vs. 11.9 +/- 9.2 mg) or a population of Sca-1-expressing cells isolated from the remaining regions of ducts (transit-amplifying cells) (31.9 +/- 24.1 mg). Almost all of the proliferative capacity of the proximal duct Sca-1-expressing cell population resides within the fraction of cells that express high levels of Sca-1 (top one-third), with the proximal region of prostatic ducts containing 7.2-fold more Sca-1(high) cells than the remaining regions. More than 60% of the high-expressing cells coexpress alpha6 integrin and the anti-apoptotic factor Bcl-2, markers that are also characteristic of stem cells of other origins. Further stratification of the phenotype of the stem cells may enable the development of rational therapies for treating prostate cancer and benign prostatic hyperplasia.

Comparison of the zones of the human prostate with the seminal vesicle: morphology, immunohistochemistry, and cell kinetics

BACKGROUND

The prostate contains three glandular zones (central, peripheral, transition) with widely differing susceptibilities to cancer and benign prostatic hyperplasia (BPH). Most of the prostate is derived from urogenital sinus, but the central zone may be derived from Wolffian duct, in common with the seminal vesicles (SV). The peripheral zone is the most frequent site of cancer and the transition zone is the almost exclusive site of BPH.

METHOD

We compared the histology and immunohistochemistry of the SV with those of the prostate zones in order to identify differences associated with susceptibility to disease or different embryological origins. Sections from the prostates of nine organ donors (aged 15-36) were stained for tissue-specific markers, antigens previously shown to stain differentially between the zones and markers of cell proliferation and cell death.

RESULTS

Neuroendocrine cells were absent from the SV and significantly fewer neuroendocrine cells were seen in the central zone compared to the peripheral zone. Most of the SV epithelium stained for lactoferrin, compared to approximately one-third of central zone and only 2% of peripheral zone epithelial cells. The proliferative index of the central zone was approximately 50% lower and the incidence of apoptotic cells approximately half that of the peripheral and transition zones.

CONCLUSIONS

The central zone has features in common with both the SV and the other zones of the prostate. The higher incidence of proliferative diseases in the transition and peripheral zones may be associated with the higher rate of cell turnover observed in these zones.

Is there a scientific basis for the therapeutic effects of serenoa repens in benign prostatic hyperplasia? Mechanisms of action

PURPOSE

The huge resurgence of interest in herbal remedies has spawned a global industry that now competes with conventional drugs as adjuncts and/or alternatives for various conditions. The medical treatment of benign prostatic hyperplasia (BPH) is no exception. Along with alpha-blockers and 5alpha-reductase inhibitors the extract of the American dwarf palm, Serenoa repens, is unquestionably the most widely used. Together with Pygeum africanum, an extract from the bark of the African plum tree, it is licensed in Germany, France and other European countries for symptomatic BPH. This review was done to analyze the large number of in vivo and in vitro laboratory studies that have been performed with extracts of Serenoa repens to elucidate mechanism(s) of action.

MATERIALS AND METHODS

A literature search (MEDLINE) revealed more than 30 publications relating to laboratory studies with extracts of Serenoa repens, addressing the question of a mechanism of action. It would appear that the n-hexane lipidosterolic extract of Serenoa repens, namely Permixon (Pierre Fabre Medicament, Boulogne, France), is a product that has uniquely been subjected to more scientific investigation than any other such preparation.

RESULTS

Placebo controlled and comparative clinical studies of Permixon indicate its efficacy for BPH/lower urinary tract symptoms. Numerous mechanisms of action have been proposed, including an antiandrogenic action, an anti-inflammatory effect and an antiproliferative influence through the inhibition of growth factors.

CONCLUSIONS

Set against the background of our current knowledge of the pathophysiology of the aging prostate, the results of these studies suggest a wide spectrum of activity. However, precise mechanism(s) of action remain obscure. Balance and caution are needed when extrapolating the results of in vitro laboratory studies to the complex human situation.

Expression of nuclear factor-kappa B and I kappa B alpha proteins in prostatic adenocarcinomas: correlation of nuclear factor-kappa B immunoreactivity with disease recurrence

PURPOSE

The nuclear transcription factor nuclear factor-kappa B (NF kappa B) and its inhibitor, I kappa B, regulate the transcription of various genes involved in cell proliferation, adhesion, and survival. The NF kappa B transcription factor complex plays a role in cancer development and progression through its influence on apoptosis. More recently, NF kappa B has been shown to be activated in human and androgen-independent prostate cancer cells. To our knowledge, this is the first study demonstrating the prognostic significance of NF kappa B immunoreactivity in prostate adenocarcinomas (PACs).

EXPERIMENTAL DESIGN

Using prostatectomy specimens, we performed immunohistochemical staining for NF kappa B and I kappa B alpha (Santa Cruz Biotechnology) on formalin-fixed, paraffin-embedded sections obtained from 136 patients with PAC. Cytoplasmic and nuclear immunoreactivity was scored for intensity and distribution, and results were correlated with preoperative serum prostate-specific antigen, tumor grade, stage, DNA ploidy (Feulgen spectroscopy), and biochemical disease recurrence.

RESULTS

Forty-nine percent of PACs overexpressed cytoplasmic NF kappa B, and 63% showed decreased I kappa B expression. Cytoplasmic NF kappa B overexpression correlated with advanced tumor stage (P = 0.048), aneuploidy (P = 0.022), and biochemical disease recurrence (P = 0.001). When we compared the means for the NF kappa B-positive and -negative subgroups, NF kappa B overexpression correlated with preoperative serum prostate-specific antigen (P = 0.04) and DNA index (P = 0.05). Fifteen percent of PACs expressed nuclear NF kappa B, which correlated with high tumor grade (P = 0.001) and advanced stage (P = 0.05). Decreased I kappa B alpha expression correlated with high tumor grade (P = 0.015). On multivariate analysis, tumor stage (P = 0.043) and NF kappa B overexpression (P = 0.006) were independent predictors of biochemical recurrence.

CONCLUSION

These results support a role for NF kappa B pathway proteins in the tumorigenesis of PACs. The findings are also consistent with reported experimental studies suggesting a new strategy of combined chemotherapy and specific NF kappa B blockade in decreasing the rate of disease relapse.

MOLECULAR AND CELLULAR PATHOGENESIS OF BENIGN PROSTATIC HYPERPLASIA

PURPOSE

Symptomatic benign prostatic hyperplasia (BPH) is one of the most common ailments seen by the urologist. Significant advances have occurred in medical and surgical therapy, and in the understanding of the biology of this disease. However, the basic science literature is often conflicting and confusing, without a unified voice. We report the current state of knowledge of the molecular and cellular basis of BPH.

MATERIALS AND METHODS

We compiled and interpreted basic science studies relevant to BPH pathogenesis.

RESULTS

Cellular alterations that include changes in proliferation, differentiation, apoptosis and senescence in the epithelium and stroma are implicated in BPH pathogenesis. Molecular analyses have yielded numerous candidate genes important in disease progression. Differential expression of cytokines and growth factors in BPH tissue suggests roles for inflammation and hypoxia. Through the use of cell culture models the complex regulatory mechanisms of growth control in BPH are becoming defined.

CONCLUSIONS

The scientific endeavor has resulted in great strides in our understanding of BPH on a molecular and cellular level. It is hopeful that basic science and translational research will improve treatment and prevention strategies for this common disease of elderly men.

Abnormalities of apoptotic and cell cycle regulatory proteins in distinct histopathologic components of benign prostatic hyperplasia

INTRODUCTION

Benign prostatic hyperplasia (BPH) is a slowly progressive abnormal glandular enlargement with heterogeneous morphology. Disruption of apoptotic pathways has been suggested as an important regulatory mechanism in this common and significantly morbid disease.

METHODS

Prostatic tissue from 20 patients with BPH and no prior or subsequent prostatic carcinoma was obtained by transurethral prostatectomy (TURP) at the University of California Davis. Apoptotic regulatory proteins: BCL2, BAX and p27 were analyzed by immunohistochemistry and evaluated for expression in four distinct histologic patterns: hyperplastic epithelium, nodules, dilated glands and atrophic/inflammatory glands.

RESULTS

Particularly striking was the decreased expression of BAX and an abnormal BCL2 : BAX ratio within all nodules relative to expression in other epithelial patterns. p27 expression was decreased in 35% of the hyperplastic epithelial areas and 10% of the nodules.

DISCUSSION

Overall, abnormal expression of BCL2, BAX and/or p27 was identified in the hyperplastic epithelium of 19 (90%) of specimens and all 12 (100%) of the hyperplastic nodules. The high frequency of abnormalities in apoptosis regulatory genes, suggests that alteration of apoptotic pathways is important for the development of this condition.

Biologic feature of prostatic hyperplasia developed in spontaneously hypertensive rats

OBJECTIVES

To investigate alterations in cell kinetic and cellular composition in prostatic hyperplasia developed in spontaneously hypertensive (SH) rats from 15 to 54 weeks of age.

METHODS

Male SH rats (n = 20) and their normotensive counterparts, Wistar-Kyoto rats (n = 20), were studied. At 15, 29, 40, and 54 weeks of age, the ventral prostate was obtained to evaluate (a) cell proliferation by the proliferation index using proliferating cell nuclear antigen immunostaining and (b) apoptosis by the apoptotic index using the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling assay. The percentage of area density of smooth muscle and fibroblastic tissues was determined with a computerized image analysis system after alpha-actin and vimentin immunostaining, respectively.

RESULTS

Compared with the data in the Wistar-Kyoto rats during the observation period, a significantly increased proliferation index in both epithelium and stroma (P <0.01) and a slightly increased apoptotic index in the epithelium without apoptotic cells in the stroma, with an imbalance in favor of cell proliferation, were noted in the prostatic hyperplasia of the SH rats. The value of the proliferation index was greatly increased in both the epithelium and the stroma of the SH rats between 15 and 29 weeks (P <0.05) but continued relatively steady from 29 to 54 weeks. A significantly increased percentage of smooth muscle area (P <0.01) and a much greater percentage of area density of smooth muscle than that of fibroblastic tissues (P <0.01) were observed in the prostatic hyperplasia of the SH rats.

CONCLUSIONS

The prostatic hyperplasia of SH rats may develop from both epithelial and stromal growth and could ultimately be promoted by an imbalance in favor of proliferative activity.

Survivin and Bcl-2 expression in prostatic adenocarcinomas

CONTEXT

Dysregulated cell proliferation caused by inhibitors of programmed cell death (apoptosis) contributes to tumor progression and spread. Aberrant expression of Bcl-2, the most notable inhibitor of apoptosis, has been well characterized in several human malignancies. Recent studies have described a novel apoptosis inhibitor, survivin, in human carcinomas, although its exact role remains to be characterized.

OBJECTIVE

The purpose of this study was to evaluate the immunohistochemical expression of Bcl-2 and survivin proteins in prostate cancer and to correlate the results with clinicopathologic variables.

DESIGN

Formalin-fixed, paraffin-embedded tissue sections from 138 cases of prostatic adenocarcinomas (PACs) were immunostained by an automated method using specific antibodies against survivin and Bcl-2. Staining was semiquantitatively scored based on both intensity and distribution, and results were correlated with morphologic and prognostic variables.

RESULTS

Of the 138 PACs tested, 113 (82%) expressed survivin. We found no correlation between survivin expression and prognostic variables, including grade, stage, DNA content (ploidy), and recurrence. Bcl-2 expression was positive in 95 (69%) of these 138 cases and correlated with nondiploid DNA content. Fourteen (50%) of 28 nondiploid PACs expressed Bcl-2, compared to 17 (25%) of 68 diploid tumors (P =.02). A trend for association of Bcl-2 expression with tumor stage was noted as follows: 21 (39%) of 54 advanced-stage PACs expressed Bcl-2, in comparison with 20 (24%) of 84 low-stage tumors (P =.07). On univariate analysis, 25 (48%) of the 52 PACs that recurred expressed Bcl-2, as compared with 16 (19%) of the 86 nonrecurrent PACs (P <.001). No correlation was noted between survivin and Bcl-2 expression.

CONCLUSION

Survivin is expressed in a majority of PACs and is not a prognosis-related marker, but may be a potential target for apoptosis-based therapy. Overexpression of Bcl-2 correlates with other prognostic variables and predicts disease recurrence of PACs. These data also suggest that survivin and Bcl-2 may regulate cell proliferation and cell death through different mechanisms.

Expression of Bcl-2 on leukocytes in prostatic fluid from patients with acute and chronic prostatitis

In our continuing investigation to clarify the significance of leukocytosis and its prolongation in prostatic fluid (PF) from prostatitis patients, we investigated whether expression of the antiapoptotic gene Bcl-2 on leukocytes in prostatic fluid has any relation with prolonged leukocytosis in prostatitis. The subjects were eight patients with acute bacterial prostatitis (ABP) and eight with nonbacterial prostatitis (NBP) with a history of more than 2 years. Twelve micrograms of protein obtained from leukocytes in PF were subjected to Western blot analysis. Bcl-2 was expressed in seven of eight (87.5%) and six of eight (75.0%) patients with NBP and ABP, respectively. Quantitative density analysis of the Bcl-2 band did not show any statistically significant differences between patients with NBP and those with ABP. These results suggest that the expression of antiapoptotic Bcl-2 on leukocytes in PF is not a cause of leukocyte longevity in long-term prostatitis.

Stromal/epithelial interactions of murine prostatic cell lines in vivo: a model for benign prostatic hyperplasia and the effect of doxazosin on tissue size

BACKGROUND

One of the major constraints in elucidating the mechanisms involved in the etiology of benign prostatic hyperplasia (BPH) is the lack of suitable model systems that are readily manipulable in vitro and in vivo. To address this issue, we have used murine prostatic cell lines to establish a novel in vivo model for studying prostatic cell interactions.

METHODS

Luminal, basal, and smooth muscle (SM) cell lines were inoculated alone or in combinations under the renal capsule of intact or castrated male mice, and the growth and composition of prostatic tissue in the absence or presence of doxazosin was determined.

RESULTS

Both the luminal and basal cell lines reconstituted prostatic tissue if co-inoculated under the renal capsule with normal SM cells, whereas none of the lines formed significant tissue when inoculated alone. Luminal cells produced and secreted prostatic secretory products. The growth of prostatic tissue formed from co-inoculation of basal and SM cells was androgen responsive. In addition, a significant reduction in prostatic tissue was noted in animals treated with doxazosin.

CONCLUSION

We have established an in vivo model that uses prostatic epithelial and SM cell lines for investigating cellular interactions between epithelial and SM cells that regulate prostatic growth and function. This model will be useful for delineating the mechanisms by which prostatic cells interact and in determining the efficacy of new approaches aimed at interfering with prostatic stromal/epithelial interactions that result in abnormal cellular proliferation.

Effects of cyclic stretch on prostatic cells in culture

PURPOSE

The fundamental process in the development of benign prostatic hyperplasia (BPH) is a loss of homeostasis between cell proliferation and apoptosis. Prostatic smooth muscle cells contract under adrenergic control. The response of a cell to stretch may have a role in the pathogenesis of BPH.

MATERIALS AND METHODS

Monolayer cultures of human prostatic stromal and epithelial cell lines were exposed to cyclic stretch for 48 hours.

RESULTS

Cyclic stretch conferred resistance to etoposide induced apoptosis. Underlying this apoptotic resistance was increased expression of the anti-apoptotic Bcl-2 family of proteins. As measured by thymidine incorporation, the rate of proliferation also increased in benign epithelial cells under cyclic stretch conditions. Furthermore, an increase in the production of platelet-derived growth factor by stromal cells and transforming growth factor-beta by epithelial cells occurred under such conditions.

CONCLUSIONS

The observed changes in proliferation and apoptosis may contribute to the understanding of BPH, ultimately leading to therapeutic and preventive applications.

Pharmacokinetics and pharmacodynamics of TF-505, a novel nonsteroidal 5alpha-reductase inhibitor, in normal subjects treated with single or multiple doses

AIMS

To assess the tolerability, pharmacokinetics and pharmacodynamics of a novel nonsteroidal and noncompetitive inhibitor of type I and type II 5alpha-reductases, (-)-(S)-4-[1-[4-[1-(4-isobutylphenyl) butoxy]benzoyl]indolizin-3-yl]butyric acid (TF-505), after single and multiple oral doses in healthy volunteers.

METHODS

In the single-dose study, six young adult males in each dose group received 25 mg or 50 mg of TF-505, and six older males (>or= 40 years) in each dose group received 75 mg or 100 mg of TF-505. The subjects were given the drug in ascending dose and in the fasting state. Six subjects also received 50 mg of TF-505 after breakfast in a two-period crossover manner. In the multiple-dose study, six older males in each dose group received 12.5 mg or 25 mg TF-505 after breakfast daily for 7 days. Plasma concentrations of TF-505, dihydrotestosterone (DHT) and testosterone were measured. The pharmacokinetics of TF-505 were analysed by a compartment model with first-order absorption, first-order elimination and a lag time. Pharmacokinetic and pharmacodynamic relationships were evaluated by indirect response modelling with inhibition of input.

RESULTS

Maximum plasma concentration (Cmax) and the area under the concentration-time curve (AUC) increased proportionately after the single dose up to 50 mg and with the multiple doses. Linearity was not detected between 75 and 100 mg of TF-505. Dose dependency was also noted for the effect of TF-505 on DHT concentrations following single doses up to 50 mg and multiple doses. Plasma DHT concentrations decreased maximally to 58.2, 49.5, 54.2 and 49.8% of basal values at 8-12 h after single administration of 25, 50, 75 and 100 mg TF-505, respectively, and to 60.5 and 49.4% at the 7th and 5th dose following multiple doses of 12.5 and 25 mg TF-505, respectively. The predicted effect curves matched the observed data when the indirect response model was applied to the time course of the suppressant effect of TF-505 on plasma DHT concentrations after both the single and multiple studies. Fifty percent inhibitory concentrations (IC50) of 0.82, 1.48, 1.31 and 0.88 micro g ml(-1), zero-order rate constants for the onset of plasma DHT concentration changes (kin) of 17.8, 17.4, 17.0 and 10.7% h(-1) and first-order rate constants for increase in plasma DHT concentrations to basal values (kout) of 0.17, 0.16, 0.17 and 0.10 h(-1) for the single study at doses of 25, 50, 75 and 100 mg, respectively, were attained. In the multiple-dose study, IC50s were 1.74 and 1.49 micro g ml(-1) for the 12.5 and 25 mg doses, respectively. No serious adverse events related to TF-505 were observed.

CONCLUSIONS

TF-505 was well tolerated in healthy male volunteers. Accumulation of TF-505 in plasma was not observed during multiple dosing. The indirect response model described the relationships between pharmacokinetics and pharmacodynamics of TF-505. Such modelling is expected to yield an appropriate dosage regimen in subsequent clinical trials.

Molecular characterization of prostate hyperplasia in prolactin-transgenic mice by using cDNA representational difference analysis

BACKGROUND

Transgenic mice overexpressing the rat prolactin (PRL) gene develop a dramatic enlargement of the prostate gland. The objective of this study was to characterize the molecular mechanisms in the prostate of importance for the prostate hyperplasia seen in these transgenic mice.

METHODS

cDNA representational difference analysis (cDNA RDA) was used to isolate differentially expressed transcripts in the prostate hyperplasia of the transgenic mice compared with wildtype littermates. Furthermore, cDNA microarray analysis was used to verify the RDA output.

RESULTS

Here we report 10 transcripts, some of them described to be involved in proliferation and apoptosis, which are differentially expressed in the enlarged transgenic prostates compared with controls.

CONCLUSION

The identified differentially expressed transcripts presented herein supports molecular similarities between the prostate hyperplasia of PRL-transgenic mice and human BPH that may contribute to explain the molecular basis of prostate hyperplasia.

Transduction and apoptosis induction in the rat prostate, using adenovirus vectors

Proapoptotic adenovirus vectors offer great promise for the treatment of cancer and nonmalignant conditions. Benign prostate hyperplasia (BPH) is a common nonmalignant enlargement of the prostate that involves epithelial, stromal, and smooth muscle components of the gland. We tested the hypothesis that an adenovirus vector expressing Fas ligand can be used to induce apoptosis in the prostate. We analyzed the efficiency of transduction and apoptosis induction in primary cultures of human prostate cells after adenovirus-mediated gene transfer. Efficient transduction was observed in primary prostate epithelial cells. Stromal and smooth muscle cells were more difficult to transduce, as no coxsackie-adenovirus receptor (CAR) expression was detectable on these cells. However, transduction was achieved in these cells when the multiplicity of infection was increased to 100 focal-forming units per cell, or when the vectors were delivered as calcium phosphate precipitates. Infection of all three primary prostate cell types with an adenovirus vector that expresses Fas ligand (AdFasL/G) resulted in rapid apoptosis. Direct injection of the rat prostate with an adenovirus vector carrying luciferase resulted in substantial luciferase expression. TUNEL analysis demonstrated that AdFasL/G administration induced low-level apoptosis in prostatic epithelial cells throughout the gland. As a first step toward enhancing the efficiency of prostate transduction in vivo, we tested an adenovirus vector that was engineered to have an expanded tropism. This vector, AdZ.F2K(pK7), was 10- to 500-fold more efficient than unmodified vectors in transducing prostate epithelial, smooth muscle, and stromal cells in culture. Moreover, AdZ.F2K(pK7) was more efficient than an unmodified vector at transducing the rat prostate in vivo, although the effect was dose dependent.

Molecular 'palpation' of BPH: a tale of MAPK signalling?

Benign prostatic hyperplasia (BPH) is a very common cause of hospitalization and surgery is currently the most effective therapy. MAP kinases (MAPKs) are a group of protein kinases with an important function in integrating physiological and pathological stimuli that might impact on cellular growth, differentiation and programmed cell death (apoptosis). Certain components of the MAPK signal-transduction pathways are involved in stimulus-specific fine-tuning of the activities mediated by the various MAPK families. As homeostasis is impaired in the hyperplastic prostate, aberrant coordination of the MAPK cascades might be implicated in a proliferative-apoptotic imbalance. Here, we hypothesize that the pathogenesis of BPH might be facilitated by functional anomalies in the MAPK circuitry and postulate that pharmacological 'rewiring' of MAPK pathways offers a potentially exciting new avenue for improved therapeutic control of clinical BPH.