Elevated Estrogen Receptor Expression in Human Prostatic Stromal Cells by Androgen Ablation Therapy

Smoking Is Associated With Basal Cell Hyperplasia on Prostate Biopsy Specimens

OBJECTIVES

To the best of our knowledge, no study has analyzed the association between cigarette smoking and prostate basal cell proliferation. Therefore, we sought to evaluate whether smoking status is associated with the presence of basal cell hyperplasia (BCH).

METHODS

We performed a retrospective analysis of 8,196 men aged 50 to 75 years with prostate-specific antigen values between 2.5 µg/mL and 10 µg/mL and prior negative biopsy who were enrolled in the (REDUCE) trial. Cigarette smoking status was divided into current, former, or never categories at enrollment. The association between smoking and baseline BCH was evaluated, with logistic regression in univariable and multivariable analysis.

RESULTS

A total of 1,233 (15.1%) men were current smokers, 3,206 (39.1%) were former smokers, and 3,575 (45.8%) were never smokers. In univariable analysis, current smoking was associated with higher baseline BCH occurrence compared with never (odds ratio [OR], 1.87; 95% confidence interval [CI], 1.14-3.10) and former smokers (OR, 1.77; 95% CI, 1.06-2.95). Similar results were found after adjusting for patient characteristics (current vs never smokers: OR, 1.92; 95% CI, 1.14-3.26; current vs former smokers: OR, 1.71; 95% CI, 1.01-2.91).

CONCLUSIONS

Among men undergoing prostate biopsy, all of whom had a negative biopsy result, current smoking at enrollment was independently associated with BCH in standard peripheral zone prostate biopsies.

Prolactin promotes a partial recovery from the atrophy of both male and female gerbil prostates caused by castration

BACKGROUND

The male and female prostates are controlled by steroid hormones, suffering important morphological and physiological changes after castration. Prolactin is involved in the regulation of the male prostate, having already been identified in the tissue, acting through its receptor PRLR. In the Mongolian gerbil, in addition to the male prostate, the female prostate is also well developed and active in its secretion processes. The aim of the present study was to evaluate the effects of exposure to exogenous prolactin in the prostate of both intact and castrated male and female gerbils in order to establish if prolactin administration can sustain prostate cell activity in conditions of sexual hormone deprivation.

METHODS

The morphological analyses were performed by biometric analysis, lesion histological analysis and morphometric-stereological aspects. In addition, immune-cytochemical tests were performed for prolactin and its receptor, as well as for the receptors of androgen and oestrogen and serum prolactin dosage. All data were submitted to ANOVA or Kruskal-Wallis tests for comparison between groups. P < 0.05 was considered to be statistically significant.

RESULTS

The results showed a strong influence of prolactin on the morphology of the prostate, with the development of important epithelial alterations, after only 3 days of administration, and an expressive epithelial cell discard process after 30 days of administration. Prolactin acts in synergy with testosterone in males and mainly with oestrogens in females, establishing different steroid hormonal receptor immunoreactivity according to sex. It was also demonstrated that prolactin can assist in the recovery from some atrophic effects caused in the gland after castration, without causing additional tissue damage.

CONCLUSIONS

The prolactin and its receptor are involved in the maintenance of the homeostasis of male and female gerbils, and also cause distinct histological alterations after exogenous exposure for 3 and 30 days. The effects of prolactin are related to its joint action on androgens and oestrogens and it can also assist in the recovery from the atrophic effects of castration.

Resistance to Antiandrogens in Prostate Cancer: Is It Inevitable, Intrinsic or Induced?

Increasingly sophisticated therapies for chemical castration dominate first-line treatments for locally advanced prostate cancer. However, androgen deprivation therapy (ADT) offers little prospect of a cure, as resistant tumors emerge rather rapidly, normally within 30 months. Cells have multiple mechanisms of resistance to even the most sophisticated drug regimes, and both tumor cell heterogeneity in prostate cancer and the multiple salvage pathways result in castration-resistant disease related genetically to the original hormone-naive cancer. The timing and mechanisms of cell death after ADT for prostate cancer are not well understood, and off-target effects after long-term ADT due to functional extra-prostatic expression of the androgen receptor protein are now increasingly being recorded. Our knowledge of how these widely used treatments fail at a biological level in patients is deficient. In this review, I will discuss whether there are pre-existing drug-resistant cells in a tumor mass, or whether resistance is induced/selected by the ADT. Equally, what is the cell of origin of this resistance, and does it differ from the treatment-naïve tumor cells by differentiation or dedifferentiation? Conflicting evidence also emerges from studies in the range of biological systems and species employed to answer this key question. It is only by improving our understanding of this aspect of treatment and not simply devising another new means of androgen inhibition that we can improve patient outcomes.

The Development of Prostate Adenocarcinoma in a Transgender Male to Female Patient: Could Estrogen Therapy Have Played a Role?

BACKGROUND

Prostate adenocarcinoma (PCa) is a rare diagnosis in the male to female transgender (MtFT) population with only a few case reports published in the current medical literature. Long standing beliefs of androgen suppression conferring a protective effect against prostate cancer development have been challenged by the literature citing adenocarcinoma development in the prostate of rodent models following combined estrogen and testosterone treatment.

MATERIALS AND METHODS

We herein present a MtFT patient who presented with high grade PCa following 20 years of exogenous estrogen therapy.

RESULTS

Immunohistochemical (IHC) localization of estrogen receptor alpha (ER-α) and progesterone receptor (PR) demonstrated positive staining in stromal cells; while, androgen receptor (AR) demonstrated positive staining in malignant glands and weak scattered staining in adjacent stroma.

CONCLUSION

This pattern of staining raises concern for a possible contributing role of exogenous estrogen therapy in tumorigenesis. As awareness of gender dysphoria and acceptance of gender reassignment surgery has seen a recent increase, the unique needs of this population must be recognized. Prostate 77:824-828, 2017. © 2017 Wiley Periodicals, Inc.

Molecular pathogenesis of human prostate basal cell hyperplasia

BACKGROUND

Understanding the molecular pathogenesis of distinct phenotypes in human benign prostatic hyperplasia (BPH) is essential to improving therapeutic intervention. Current therapies target smooth muscle and luminal epithelia for relief of lower urinary tract symptoms (LUTS) due to BPH, but basal cell hyperplasia (BCH) remains untargeted. The incidence of has been reported at 8-10%, but a molecular and cellular characterization has not been performed on this phenotype.

METHODS

Using freshly digested tissue from surgical specimens, we performed RNA-seq analysis of flow cytometry-purified basal epithelia from 3 patients with and 4 patients without a majority BCH phenotype. qPCR was performed on 28 genes identified as significant from 13 non-BCH and 7 BCH specimens to confirm transcriptomic analysis. IHC was performed on several non-BCH and BCH specimens for 3 proteins identified as significant by transcriptomic analysis.

RESULTS

A total of 141 human BPH specimens were analyzed for the presence of BCH. Clinical characteristics of non-BCH and BCH cohorts revealed no significant differences in age, PSA, prostate volume, medical treatment, or comorbidities. Quantitation of cellular subsets by flow cytometry in 11 BCH patients vs. 11 non-BCH patients demonstrated a significant increase in the ratio of basal to luminal epithelia in patients with BCH (P <0.05), but no significant differences in the total number of leukocytes. RNA-seq data from flow cytometry isolated basal epithelia from patients with and without BCH were subjected to gene set enrichment analysis of differentially expressed genes, which revealed increased expression of members of the epidermal differentiation complex. Transcriptomic data were complemented by immunohistochemistry for members of the epidermal differentiation complex, revealing a morphological similarity to other stratified squamous epithelial layers.

CONCLUSIONS

Increased expression of epidermal differentiation complex members and altered epithelial stratification resembles the progression of other metaplastic diseases. These data provide insight into the plasticity of the human prostate epithelium and suggest a classification of basal cell hyperplasia as a metaplasia.

Characterization of fibrillar collagens and extracellular matrix of glandular benign prostatic hyperplasia nodules

Objective

Recent studies have associated lower urinary tract symptoms (LUTS) in men with prostatic fibrosis, but a definitive link between collagen deposition and LUTS has yet to be demonstrated. The objective of this study was to evaluate ECM and collagen content within normal glandular prostate tissue and glandular BPH, and to evaluate the association of clinical parameters of LUTS with collagen content.

Methods

Fibrillar collagen and ECM content was assessed in normal prostate (48 patients) and glandular BPH nodules (24 patients) using Masson's trichrome stain and Picrosirius red stain. Second harmonic generation (SHG) imaging was used to evaluate collagen content. Additional BPH tissues (n = 47) were stained with Picrosirius red and the association between clinical parameters of BPH/LUTS and collagen content was assessed.

Results

ECM was similar in normal prostate and BPH (p = 0.44). Total collagen content between normal prostate and glandular BPH was similar (p = 0.27), but a significant increase in thicker collagen bundles was observed in BPH (p = 0.045). Using SHG imaging, collagen content in BPH (mean intensity = 62.52; SEM = 2.74) was significantly higher than in normal prostate (51.77±3.49; p = 0.02). Total collagen content was not associated with treatment with finasteride (p = 0.47) or α-blockers (p = 0.52), pre-TURP AUA symptom index (p = 0.90), prostate-specific antigen (p = 0.86), post-void residual (PVR; p = 0.32), prostate size (p = 0.21), or post-TURP PVR (p = 0.51). Collagen content was not associated with patient age in patients with BPH, however as men aged normal prostatic tissue had a decreased proportion of thick collagen bundles.

Conclusions

The proportion of larger bundles of collagen, but not total collagen, is increased in BPH nodules, suggesting that these large fibers may play a role in BPH/LUTS. Total collagen content is independent of clinical parameters of BPH and LUTS. If fibrosis and overall ECM deposition are associated with BPH/LUTS, this relationship likely exists in regions of the prostate other than glandular hyperplasia.

Effects of the commercial antiandrogen flutamide on the biomarkers of reproduction in male Murray rainbowfish (Melanotaenia fluviatilis)

The endocrine responses in male Murray rainbowfish (Melanotaenia fluviatilis) were evaluated after exposures to biologically active concentrations of the nonsteroidal pharmaceutical, flutamide. Fish were exposed to nominal concentrations of 125 µg/L, 250 µg/L, 500 µg/L, and 1000 µg/L of flutamide for 7 d, after which plasma vitellogenin concentration; brain aromatase activity; and hepatic expression of the genes for vitellogenin, choriogenin, and androgen and estrogen receptors were assessed. Qualitative assessment of the testes of the fish exposed to flutamide exhibited hindrance in the transformation of spermatogonia to spermatozoa and increased testicular anomalies, such as multinucleated and pyknotic cells and interstitial fibrosis. An increase in the hepatosomatic index with respect to the controls was noted after treating the fish with flutamide at all concentrations. Vitellogenin was induced in plasma in the 1000 µg/L flutamide group. The activity of aromatase in the brain declined significantly after exposures to flutamide at all concentrations. Males exposed to 1000 µg/L of flutamide showed a downregulation in the genes encoding androgen receptors α and β. The expression of the gene for the estrogen receptor α was induced and of vitellogenin was downregulated after treatment with 250 µg/L to 1000 µg/L of flutamide. The results suggest that 7-d exposures to 125 µg/L to 1000 µg/L flutamide can impair the reproductive endocrine system in male Murray rainbowfish at multiple levels by an antiandrogenic mode of action.

[CYP17A1 inhibitors in prostate cancer: mechanisms of action independent of the androgenic pathway]

INTRODUCTION

The objective of this article is to review the mechanisms of action of abiraterone acetate, independently of the androgenic pathway.

MATERIAL AND METHOD

A systematic review of the literature was carried out on Medline and Embase databases.

RESULTS

Inhibition of CYP17A1 with abiraterone acetate induces changes in steroid metabolism, whose main component is the reduction of DHEA and androstenedione synthesis. This results in inhibition of androgen pathway in prostatic cancerous epithelial cell. Regardless of androgen activation pathway, abiraterone acetate could also act via an alternative mechanism of action not fully elucidated. Stromal cells, like tumor cells, could undergo the effects of CYP17A1 inhibition, resulting in blocking the production of secondary mediators that contribute to tumor progression. Similarly, it has been suggested that abiraterone acetate efficacy may be related to its ability to alter intratumoral concentrations of estrogen and progesterone.

CONCLUSION

The validation of these mechanisms could contribute to improved therapeutic strategies based on the use of abiraterone acetate alone or in combination.

Variations in circulating sex steroid levels in metastatic prostate cancer patients with combined androgen blockade: observation and implication

Testosterone is the major precursor of estradiol (E2) in men. We hypothesized that, in metastatic prostate cancer, androgen deprivation therapy suppression of serum androgen to the castration level may also disrupt serum E2 level, and variation in serum E2 level might play a role in the development of castration-resistant prostate cancer. Our investigation was designed to observe the variation in circulating oestrogen and androgen levels in metastatic prostate cancer patients after combined androgen blockade, and to explore the possible clinical significance. We recruited 105 consecutive metastatic prostate cancer patients who were treated with combined androgen blockade from June to August 2011, and divided them into three groups according to different hormone-sensitivity status, including 58 hormone-sensitive prostate cancers, 27 after failure of first-line hormone therapy (androgen-independent prostate cancer) and 20 castration-resistant prostate cancers. Another 36 consecutive patients with treatment-naive metastatic prostate cancer during the same period were used as controls. Serum testosterone, E2 and E2/testosterone (E2/T) ratio were analysed and compared between the groups. After combined androgen blockade, testosterone was suppressed to a low level, regardless of different hormone sensitivity (p > 0.05). Mean serum testosterone was 4.07, 0.15, 0.11 and 0.09 ng/mL in treatment-naive, hormone-sensitive, androgen-independent and castration-resistant prostate cancer respectively. For each group, mean E2 was 33.06, 9.23, 9.13 and 15.05 pg/mL respectively. Mean E2/T was 9.58, 269.29, 292.06 and 996.67 respectively. Recovery of E2 and increased E2/T ratio were more significantly associated with combined androgen blockade failure, especially in castration-resistant prostate cancer (p < 0.001). This study indicated that metabolism of oestrogen might change during combined androgen blockade in metastatic prostate cancer patients, and oestrogen-related pathways might play a role in the development of castration-resistant prostate cancer.

The impact of cow's milk-mediated mTORC1-signaling in the initiation and progression of prostate cancer

Prostate cancer (PCa) is dependent on androgen receptor signaling and aberrations of the PI3K-Akt-mTORC1 pathway mediating excessive and sustained growth signaling. The nutrient-sensitive kinase mTORC1 is upregulated in nearly 100% of advanced human PCas. Oncogenic mTORC1 signaling activates key subsets of mRNAs that cooperate in distinct steps of PCa initiation and progression. Epidemiological evidence points to increased dairy protein consumption as a major dietary risk factor for the development of PCa. mTORC1 is a master regulator of protein synthesis, lipid synthesis and autophagy pathways that couple nutrient sensing to cell growth and cancer. This review provides evidence that PCa initiation and progression are promoted by cow´s milk, but not human milk, stimulation of mTORC1 signaling. Mammalian milk is presented as an endocrine signaling system, which activates mTORC1, promotes cell growth and proliferation and suppresses autophagy. Naturally, milk-mediated mTORC1 signaling is restricted only to the postnatal growth phase of mammals. However, persistent consumption of cow´s milk proteins in humans provide highly insulinotropic branched-chain amino acids (BCAAs) provided by milk´s fast hydrolysable whey proteins, which elevate postprandial plasma insulin levels, and increase hepatic IGF-1 plasma concentrations by casein-derived amino acids. BCAAs, insulin and IGF-1 are pivotal activating signals of mTORC1. Increased cow´s milk protein-mediated mTORC1 signaling along with constant exposure to commercial cow´s milk estrogens derived from pregnant cows may explain the observed association between high dairy consumption and increased risk of PCa in Westernized societies. As well-balanced mTORC1-signaling plays an important role in appropriate prostate morphogenesis and differentiation, exaggerated mTORC1-signaling by high cow´s milk consumption predominantly during critical growth phases of prostate development and differentiation may exert long-term adverse effects on prostate health. Attenuation of mTORC1 signaling by contemporary Paleolithic diets and restriction of dairy protein intake, especially during mTORC1-dependent phases of prostate development and differentiation, may offer protection from the most common dairy-promoted cancer in men of Western societies.

Anterior prostate epithelial AR inactivation modifies estrogen receptor expression and increases estrogen sensitivity

Androgens influence prostate growth and development, so androgen withdrawal can control progression of prostate diseases. Although estrogen treatment was originally used to induce androgen withdrawal, more recently direct estrogen effects on the prostate have been recognized, but the nature of androgen-estrogen interactions within the prostate remain poorly understood. To characterize androgen effects on estrogen sensitivity in the mouse prostate, we contrasted models of castration-induced androgen withdrawal in the prostate stromal and epithelial compartments with a prostate epithelial androgen receptor (AR) knockout (PEARKO) mouse model of selective epithelial AR inactivation. Castration markedly increased prostate epithelial estrogen receptor (ER)α immunoreactivity compared with very low ERα expression in intact males. Similarly, strong basal and luminal ERα expression was detected in PEARKO prostate of intact males, suggesting that epithelial AR activity regulated epithelial ERα expression. ERβ was strongly expressed in intact, castrated, and PEARKO prostate. However, strong clusters of epithelial ERβ positivity coincided with epithelial stratification in PEARKO prostate. In vivo estrogen sensitivity was increased in PEARKO males, with greater estradiol-induced prostate growth and epithelial proliferation leading to squamous metaplasia, featuring markedly increased epithelial proliferation, thickening, and keratinization compared with littermate controls. Our results suggest that ERα expression in the prostate epithelial cells is regulated by local, epithelia-specific, androgen-dependent mechanisms, and this imbalance in the AR- and ER-mediated signaling sensitizes the mature prostate to exogenous estrogens.

The evolving role of oestrogens and their receptors in the development and progression of prostate cancer

CONTEXT

Oestrogens were proven effective in the hormonal treatment of advanced prostate cancer (PCa) >60 yr ago and are still used as second-line hormonal therapy. Paradoxically, oestrogens might also be involved in the development and progression of PCa.

OBJECTIVE

To examine mechanisms of how oestrogens may affect prostate carcinogenesis and tumour progression.

EVIDENCE ACQUISITION

Recent data obtained from animal, experimental, and clinical studies were reviewed.

EVIDENCE SYNTHESIS

The human prostate is equipped with a dual system of oestrogen receptors (oestrogen receptor alpha [ERalpha], oestrogen receptor beta [ERbeta]) that undergoes profound remodelling during PCa development and tumour progression. In high-grade prostatic intraepithelial neoplasia (HGPIN), the ERalpha is upregulated and most likely mediates carcinogenic effects of estradiol as demonstrated in animal models. Preliminary clinical studies with the ERalpha antagonist toremifene have identified the ERalpha as a promising target for PCa prevention. The partial loss of the ERbeta in HGPIN indicates that the ERbeta acts as a tumour suppressor. The ERbeta is generally retained in hormone-naïve PCa but is partially lost in castration-resistant disease. The progressive emergence of the ERalpha and the oestrogen-regulated progesterone receptor (PR) during PCa progression and hormone-refractory disease suggests that these tumours can use oestrogens and progestins for their growth. The TMPRSS2-ERG gene fusion recently reported as a potentially aggressive molecular subtype of PCa is regulated by ER-dependent signalling. TMPRSS2-ERG expression has been found to be increased by ERalpha agonist (oestrogens) and decreased by ERbeta agonists.

CONCLUSIONS

Oestrogens and their receptors are implicated in PCa development and tumour progression. There is significant potential for the use of ERalpha antagonists and ERbeta agonists to prevent PCa and delay disease progression. Tumours equipped with the pertinent receptors are potential candidates for this new therapeutic approach.

Flutamide protects against trauma-hemorrhage-induced liver injury via attenuation of the inflammatory response, oxidative stress, and apopotosis

Although studies have shown that administration of testosterone receptor antagonist, flutamide, following trauma-hemorrhage, improves hepatic, cardiovascular, and immune functions, the precise cellular/molecular mechanisms responsible for producing these salutary effects remain largely unknown. To study this, male C3H/HeN mice were subjected to a midline laparotomy and hemorrhagic shock (35+/-5 mmHg for approximately 90 min), followed by resuscitation with Ringer lactate. Flutamide (25 mg/kg) or vehicle was administered subcutaneously at the onset of resuscitation, and animals were killed 2 h thereafter. Hepatic injury was assessed by plasma alpha-glutathione S-transferase concentration, liver myeloperoxidase activity, and nitrotyrosine formation. Hepatic malondialdehyde and 4-hydroxyalkenals (lipid peroxidation indicators), cellular DNA fragmentation, and the expression of inducible nitric oxide synthase and hypoxia-inducible factor-1alpha were also evaluated. Cytokines (TNF-alpha, IL-6) and chemokines (keratinocyte-derived chemokine and monocyte chemoattractant protein-1) levels were determined by cytometric bead array. The results indicate that flutamide administration after trauma-hemorrhage reduced liver injury, which was associated with decreased levels of alpha-glutathione S-transferase, myeloperoxidase activity, nitrotyrosine formation, lipid peroxidation, and cytokines/chemokines (systemic, liver tissue, and intracellular cytokines/chemokines). Cellular apoptosis, hepatocyte hypoxia-inducible factor-1alpha, and inducible nitric oxide synthase expression were also decreased under such conditions. Thus administration of flutamide following trauma-hemorrhage protects against liver injury via reduced inflammation, cellular oxidative stress, and apoptosis.

Morphological changes induced by androgen blockade in normal prostate and prostatic carcinoma

Maximal androgen blockade (MAB), combining a luteinizing hormone releasing hormone (LHRH) agonist and a pure or non-steroidal anti-androgen, induces significant morphologic changes in the prostate. The tumor volume, density, capsular penetration, and surgical margin involvement are strongly reduced following such treatment. On histology, normal prostate tissue and tumor undergo marked atrophy and shrinkage. Although residual cancer cells are readily identifiable in most cases, they may often be sparse and easily overlooked. The increased Gleason score apparent after MAB is most likely related to fragmentation of acinar structures, and grading is not recommended following MAB. Residual cancer cells show features of lower activity and increased apoptosis. Such therapy-induced changes may be reversible, although occasional clones of cancer cells are apparently not affected and have probably developed resistance. Finally, MAB leads to marked but reversible morphologic changes and reduction in prevalence and extent of prostatic intra-epithelial neoplasia (PIN). Monotherapy using a variety of agents causes comparable but often less extensive changes.

The role of estrogens and estrogen receptors in normal prostate growth and disease

Estrogens have significant direct and indirect effects on prostate gland development and homeostasis and have been long suspected in playing a role in the etiology of prostatic diseases. Direct effects are mediated through prostatic estrogen receptors alpha (ERalpha) and beta (ERbeta) with expression levels changing over time and with disease progression. The present review examines the evidence for a role of estrogens and specific estrogen receptors in prostate growth, differentiation and disease states including prostatitis, benign prostatic hyperplasia (BPH) and cancer and discusses potential therapeutic strategies for growth regulation via these pathways.

Mechanism responsible for the salutary effects of flutamide on cardiac performance after trauma-hemorrhagic shock: Upregulation of cardiomyocyte estrogen receptors

BACKGROUND

Although flutamide (FTM), an androgen-receptor antagonist, normalizes the depressed immune and cardiac function in males after trauma hemorrhage (T-H), the mechanism responsible for its salutary effects remains unknown. We hypothesized that the salutary effects of FTM are mediated via upregulation of estrogen receptors (ERs).

METHODS

Male Sprague-Dawley rats underwent T-H (laparotomy and 90 minutes of hemorrhage (35-40 mm Hg) and then resuscitated with 4x the volume of shed blood in the form of Ringer's lactate). FTM (25 mg/kg) or vehicle (propanediol) was injected subcutaneously 30 minutes before the end of resuscitation. At 2 hours after T-H or sham operation, cardiac output, stroke volume, heart rate, mean arterial pressure, +/- dp/dt, and total peripheral resistance were measured (n = 6 rats per group). Immediately after the measurement of cardiac function, cardiomyocytes were isolated, RNA was extracted, and expression of ER-alpha, ER-beta, and androgen-receptor (AR) mRNA in cardiomyocytes was determined by quantitative real-time polymerase chain reaction. ER-alpha, ER-beta, and AR protein levels in cardiomyocytes were also measured by Western blot analysis.

RESULTS

The depressed cardiac output, stroke volume, and +/- dp/dt after T-H were significantly improved in the FTM-treated T-H group. Moreover, the decrease in expression of ER-alpha and ER-beta mRNA and protein in cardiomyocytes in the T-H group was prevented with FTM treatment after T-H. However, expression of cardiomyocytes AR mRNA and protein were not significantly different between the T-H or sham group with or without FTM treatment.

CONCLUSIONS

These findings collectively suggest that, in addition to blockade of androgen receptors, flutamide-mediated ER upregulation is likely to play a role in mediating the salutary effect of flutamide on cardiac function after trauma hemorrhage.

SOMATOSTATIN ANALOGUES AND ESTROGENS IN THE TREATMENT OF ANDROGEN ABLATION REFRACTORY PROSTATE ADENOCARCINOMA

PURPOSE

Prostate cancer progression to androgen ablation refractory stage D3 corresponds to cancer cell escape from androgen withdrawal induced apoptosis. Of note, salvage chemotherapy can extend the median survival of approximately 10 months in patients with stage D3. Therefore, novel therapeutic strategies that target the molecular basis of androgen resistance are required.

MATERIALS AND METHODS

The MEDLINE and Current Content databases were used to find studies of the use of estrogens and somatostatin analogues for D3 prostate adenocarcinoma. We also analyzed the rationale and clinical results of our combination therapy using lanreotide and ethinylestradiol.

RESULTS

Negative experiences have been reported with somatostatin analogues as monotherapy. On the other hand, the median progression-free survival reported in our experience using lanreotide acetate plus ethinylestradiol clearly surpassed the 10-month survival historically described in stage D3 cases.

CONCLUSIONS

The use of somatostatin analogues in combination therapy for D3 prostate cancer sustains the novel concept in cancer treatment in which therapies may target not only cancer cells, but also the microenvironment in combination, which can confer protection from apoptosis.

Divergent roles for estrogens and androgens in the expression of female goat sexual behavior

We tested the hypothesis that the activation of the androgen receptor (AR) is required for full expression of female goat sexual behavior. Once a week for 6 weeks, ovariectomized (OVX) females were given priming doses of progesterone 72 and 48 h before behavioral observation. Estradiol (E(2); 100 microg), testosterone (T; 100 mg), or sesame oil was supplied 14 h before behavioral testing. Six goats received the AR antagonist flutamide (9 mg/kg sc) 8 h before and 4 h after steroid injection. Six goats received the carrier only. After 3 weeks, flutamide and carrier treatments were switched so that all females received all treatments. Treatments with E(2) and T were equally effective in eliciting estrus-typical behaviors (sniffing, courting, leg kicks, mount attempts by males, bouts of thrusting by males, ejaculations, and flehman responses) compared to treatment with oil. Flutamide treatment enhanced proceptive behaviors in E(2)-treated females compared to other treatment groups; this was most likely via enhanced tail wagging. Moreover, compared to goats given T + carrier, T + flutamide significantly reduced receptivity in females. The results of this experiment implicate the AR as an important facilitator of some aspects of the female goat sexual behavior. However, the results of this experiment do not show whether androgens influence estrous behaviors alone or in some combination with estrogen.

Relationship between upregulated oestrogen receptors and expression of growth factors in cultured, human, prostatic stromal cells exposed to estradiol or dihydrotestosterone

This study investigated the hypothesis that, in benign prostatic hyperplasia (BPH), upregulated oestrogen receptors (ER) and the action of androgens differentially regulate expression of stromal growth factors. Eight human prostatic stromal cell strains were subjected to a procedure to upregulate their ER by exposing them to 1 micromol 17beta-estradiol for 10 days followed by passage and growth in the absence of steroids. Four of the cell strains instead received 100 nmol dihydrotestosterone for 48 h. Immunoexpression of ERalpha, AR and six growth factors was quantified by flow cytometry in each case. Expression of ERalpha was significantly increased in six of eight cell strains. Expressions of six growth factors (FGF-2, FGF-7, IGF-1, TGF-beta1 NGF and e NOS) were elevated but only for FGF-7 was it significant. There was a significant positive correlation between the change in ERalpha and the change in FGF-2 and FGF-7, but not the other growth factors. Exposure to dihydrotestosterone reduced expression of ERalpha and all six growth factors, compared with oestrogen-treated cells but not significantly. It is concluded that upregulated ERalpha in prostatic stroma may have a greater modulating influence on synthesis of certain growth factors than the direct action of androgens and, by enhancing synthesis of FGF-2 and FGF-7, could play a significant role in the development of BPH.

Does Finasteride Alter the Pathology of the Prostate and Cancer Grading?

All forms of androgen-deprivation therapy, including finasteride, induce distinctive histologic changes in benign and neoplastic prostatic epithelial cells, including cytoplasmic clearing, nuclear and nucleolar shrinkage, and chromatin condensation. Treated cancer has a significantly higher architectural (Gleason) grade, lower nuclear grade, and smaller nucleolar diameter than untreated controls, creating the potential for grading bias. Recognition of these changes may be difficult in needle biopsies and lymph node metastases with treated cancer because of the subtle infiltrative pattern and inconspicuous nucleoli. The effects of finasteride may be less pronounced than other forms of therapy with variable distribution throughout the prostate; further, there may be greater sensitivity of low and intermediate-grade cancer than high-grade cancer. The Gleason grading system for cancer should not be used after finasteride treatment as it is not validated in this setting and is likely to overestimate the biologic potential of high-grade cancer observed after therapy. Chemoprevention trials with agents such as finasteride that alter morphology should not rely on cancer grading as a secondary endpoint owing to grading bias.

Androgen ablation therapy for prostate carcinoma suppresses the immunoreactive telomerase subunit hTERT

BACKGROUND

Telomerase is a ribonucleoprotein complex that protects the ends of chromosomes from degradation. Its catalytic subunit, hTERT, controls its activity. Prior data in prostate carcinoma cases indicated that immunohistochemical hTERT reactivity increases with tumor grade and may be absent in lower grade cases. The effect of complete androgen ablation (CAA) on tumor hTERT expression was uncertain.

METHODS

hTERT immunostaining was performed on the cancerous pretreatment biopsy tissue of 30 men who consecutively underwent CAA with bicalutamide and goserelin acetate for 30 days prior to undergoing radical prostatectomy, and on their tumor tissue from radical prostatectomy. As controls, biopsy and prostatectomy samples from 30 untreated men were studied. Nuclear staining was evaluated by two observers, and the change in staining between biopsy and prostatectomy samples was evaluated using the Student t test in both groups.

RESULTS

The percent of reactive tumor nuclei in treated men declined from 36.7% to 13.2% (P = 0.0001), and declined from 19.8% to 16.1% in untreated men (P = 0.4). The greater mean hTERT reactivity in the treated men's biopsy specimens was attributed to an increased proportion of higher (Gleason score > or = 7) grade tumors. The decline in hTERT immunostaining remained significant after normalizing it to that of the untreated group (P = 0.002). The original Gleason scores, corresponding declines in the percentage of reactive tumor nuclei, and significance were: Gleason score < or = 6: 11% (P = 0.03); Gleason score of 7: 23% (P < 0.006); and Gleason score > or = 8: 46% (P < 0.005) (from a mean 63% to 17%).

CONCLUSIONS

CAA for prostate carcinoma can be considered an antitelomerase therapy. The steepest reduction in telomerase activity was noted in the highest grade tumors.

Combination therapy of ethinylestradiol and somatostatin analogue reintroduces objective clinical responses and decreases chromogranin a in patients with androgen ablation refractory prostate cancer

PURPOSE

We evaluated whether a combination therapy of ethinylestradiol and somatostatin analogue can reintroduce objective clinical responses in patients with metastatic androgen ablation refractory prostate cancer (PC).

MATERIALS AND METHODS

Ten patients with stage D3 disease and bone metastases who had progression despite initial responses to combined androgen blockade and in whom antiandrogen withdrawal subsequently failed discontinued combined androgen blockade and received 1 mg ethinylestradiol orally daily and 73.9 mg lanreotide acetate intramuscularly every 4 weeks. Serum prostate specific antigen (PSA), chromogranin A (CgA), Eastern Cooperative Oncology Group performance status and bone pain scores were assessed at regular intervals. Median followup was 18 months (range 10 to 24).

RESULTS

Nine of the 10 cases (90%, 95% CI 55.5 to 99.8) had an objective clinical response, defined as a greater than 50% PSA decrease (median 87.1%, range 50.2% to 94.4%). PSA normalization (less than 4 ng/ml) was achieved in 3 cases. All patients reported significant and durable improvement in bone pain (median duration 17.5 months) and performance status (median duration 18 months) without major treatment related side effects. Two patients with disease progression died secondary to PC at 16 and 10 months, respectively. All other patients were without progression. We observed a statistically significant decrease in serum CgA during administration and at the response to therapy (median 38.4%, range 28.6% to 64.9%, (p <0.0001). Interestingly CgA was not increased at relapse.

CONCLUSIONS

This combination therapy seems to reintroduce an objective clinical response and symptomatic improvement in androgen ablation refractory PC cases.

Regulation of estrogen receptor alpha and beta expression by testosterone in the rat prostate gland

Although ER beta is known to be expressed at high levels in the rat prostate gland, its regulation is not well understood. Here we examined ER mRNA expression and the effects of testosterone administration in male rats at 1, 4 and 9 weeks of age who were castrated and/or treated with testosterone for a week, and then sacrificed. ER alpha was the major type of ER expressed in 2 week-old animals while dominant expression of ER beta mRNA was apparent in older age groups. Interestingly while ER beta expression was diminished and ER alpha mRNA increased in the castrated group, testosterone administration reversed this effect. A time-course study indicated that induction of ER beta mRNA increased within 9 hr and ER alpha decreased in 2 days after an injection (i.p.) of testosterone. Our results suggested that 1) testosterone up-regulates ER beta mRNA expression while ER alpha is down-regulated; and that 2) great changes in ER alpha and beta expression in the prostate gland during development from the newborn to adult may be due to the influence of testosterone.

Upregulation of estrogen and androgen receptors modulate expression of FGF-2 and FGF-7 in human, cultured, prostatic stromal cells exposed to high concentrations of estradiol

This study was performed to develop an experimental model in which expression of estrogen receptors (ER) by human prostatic stromal cells could be reproducibly enhanced relative to similar cells with low ER expression. The second aim was to characterise changes in expression of ER, androgen receptor (AR), FGF-2 and FGF-7 in stromal cells exposed to high and low concentrations of estradiol and testosterone mimicking the different sex hormone levels between young and elderly men. Five strains of human prostatic stromal cells, isolated from BPH resections, were grown in steroid-free medium plus 1 micromol 17beta-estradiol. After 10 days, cells were passaged and grown in the same medium without estradiol until confluent. In a second study four cell strains were exposed to high and low concentrations of 17beta-estradiol and testosterone for 10 days. Cells were labelled with fluorescent antibodies to ERalpha, AR, FGF-2 and FGF-7 and the fluorescence intensity measured by flow cytometry. Following exposure to 1 micromol estradiol, stromal cells showed reduced expression of AR and ERalpha but after passage without estradiol they showed a 25% increase in both receptors over controls. Different combinations of sex hormones induced inconsistent changes with respect to expression of ER, AR and FGFs in the various cell-strains. However, there was a highly significant correlation between AR, ER and FGF-2 and FGF-7, which was cell strain-specific. Thus, changes in sex hormone balance per se may not be solely responsible for the observed increases in prostatic ER levels in BPH. Since expression of ER is correlated with synthesis of FGF-2 and FGF-7, it is likely that increases in stromal ER may mediate the synthesis of stromally-derived growth factors which contribute to the aetiopathogenesis of benign prostatic hyperplasia.

Selective aromatase inhibition for patients with androgen-independent prostate carcinoma

BACKGROUND

First and second-generation aromatase inhibitors have shown activity in patients with androgen-independent prostate carcinoma. These early-generation aromatase inhibitors are nonselective, however, and inhibition of other steroidogenic enzymes may contribute to their reported clinical activity. The authors conducted a Phase II clinical study of letrozole to determine the safety and efficacy of a potent and selective third-generation aromatase inhibitor in men with androgen-independent prostate carcinoma.

METHODS

Forty-three men with androgen-independent prostate carcinoma were treated with oral letrozole (2.5 mg daily). Treatment was continued until progressive disease or Grade 3 toxicity developed. Response and progressive disease were defined according to recommendations of the Prostate Specific Antigen Working Group.

RESULTS

In total, 380 weeks of treatment were administered to the 43 study patients. The median duration of treatment was 8 weeks. Forty men discontinued treatment due to progressive disease. Only one patient responded to treatment with a sustained decrease > 50% in serum prostate specific antigen (PSA) levels. Three other patients experienced transient minor decreases (< 50%) in serum PSA levels. There were no serious treatment-related adverse events.

CONCLUSIONS

Selective aromatase inhibition with letrozole is not active in men with androgen-independent prostate carcinoma.

Estrogen receptor beta expression in human prostate tissue

Estrogen receptor subtype beta (ERbeta) is highly expressed in rat prostate epithelium, but its presence in human prostate needs to be confirmed. Here we investigated the expression of ERbeta in five benign (normal and/or hyperplastic) and 10 malignant (Gleasons' score 2-7) prostate tissue specimens using immunohistochemistry. Immunohistochemistry was performed on formalin-fixed, paraffin-embedded tissue sections, using a commercially available ERbeta polyclonal antibody developed against the C-terminal amino acid residue. Nuclear ERbeta expression was found in the nuclei of glandular epithelium of benign prostate tissue specimens; faint nuclear ERbeta positivity was also present in a few stromal cells around normal epithelium. Nuclear ERbeta specific immunostaining was undetectable in all prostate cancer sections.

Cultured stromal cells: an in vitro model of prostatic mesenchymal biology

BACKGROUND

Initial efforts to develop in vitro models to study prostatic biology focused on the culture and characterization of epithelial cells. Recently, attention has turned towards inclusion of stromal cells in experimental systems.

METHODS

Improved methods to isolate and culture stromal cells have been developed. An array of markers are employed to characterize subtypes of stromal cells, with particular interest in smooth muscle differentiation.

RESULTS

Defined, serum-free media are available for certain experimental applications. Conditions that promote smooth muscle differentiation have been identified. Investigators have characterized hormonal and peptide factors that regulate the growth of prostatic stromal cells, and have also described paracrine factors produced by stromal cells that influence epithelial biology.

CONCLUSIONS

Prostatic stromal-cell cultures are now widely employed by a large number of investigators for a diverse array of experimental purposes. While further refinement is required to obtain model systems that fully mimic in vivo processes, the availability of stromal- and epithelial-cell cultures provides a valuable resource for studying normal prostatic biology as well as benign prostatic hyperplasia (BPH) and cancer.

5alpha-reductase isozymes and aromatase are differentially expressed and active in the androgen-independent human prostate cancer cell lines DU145 and PC3

BACKGROUND

The presence and possible role of androgen-metabolizing enzymes in androgen-independent prostate carcinoma (CaP) are still unclear. The aim of the present study was: 1) to evaluate the pattern of androgen metabolism (relative production of 5alpha-reduced vs. 17-keto androgens); and 2) to analyze whether one or both the two known 5alpha-reductase isoforms (5alpha-R1 and 5alpha-R2) and the aromatase (Aro) are expressed and active in this pathology.

METHODS

Two different cell lines (DU145 and PC3) were used as a model of androgen-independent human CaP. In these cells, the expression of the two 5alpha-Rs and of Aro were evaluated by reverse transcription-polymerase chain reaction (RT-PCR) and Southern blot, using specific sets of oligoprimers and of [(32)P]-labeled oligoprobes; the enzymatic activities of 5alpha-R and of Aro were evaluated by radioenzymatic methods. The pH optimum for the activity of the two 5alpha-Rs was assessed in cell homogenates at different pH (from 3.5-8), using substrate concentrations similar either to 5alpha-R1 or to 5alpha-R2 Kms.

RESULTS

The two CaP cell lines DU145 and PC3, although unresponsive to androgens, possess the enzymatic machinery involved in the metabolism of this class of hormonal steroids: 5alpha-Rs, which allow their transformation into 5alpha-reduced steroids (5alpha-dihydrotestosterone, DHT, and 5alpha-androstandione, 5alpha-A), and 17beta-hydroxysteroid-oxidoreductase (17beta-HSD), which interconverts testosterone (T) and androstenedione (ADIONE); however, the two cell lines show differences in the rate of formation of these metabolites. Furthermore, two cell lines expressed the type 1 isoform of 5alpha-R, but only DU145 cells also possess 5alpha-R2. Aro is expressed and active in DU145 as well as in PC3 cells.

CONCLUSIONS

The present findings suggest that T might still be indirectly active in androgen-unresponsive CaP through its local conversion into estrogens by the action of Aro; the biological role played by the two 5alpha-Rs in androgen-independent CaP deserves further investigation.

Treatment changes in prostatic hyperplasia and cancer, including androgen deprivation therapy and radiotherapy

Substantial and characteristic changes occur in the microscopic appearance and immunophenotype of the hyperplastic prostate and adenocarcinoma following androgen deprivation therapy and radiotherapy. These changes are rarely seen in untreated cancer, and in the authors' opinion, the combinations of features following therapy are sufficiently distinctive to warrant recognition. Pathologists must be aware of these distinct changes because of the reliance placed on nuclear and nucleolar size in the identification of prostate cancer, particularly in small specimens and lymph node metastases.

Estrogen receptor expression in prostate cancer and premalignant prostatic lesions

Estrogens have been implicated in prostatic cancerogenesis and tumor progression. The mechanisms underlying estrogen signaling in human prostate tissue, however, remain poorly understood. Using immunohistochemical and in situ hybridization (ISH) techniques, the present study demonstrates the classical estrogen receptor (ERalpha) in premalignant lesions and prostatic adenocarcinoma through the various stages of the disease. Conversely, the novel characterized ERbeta subtype was undetectable in human prostate tissue. High-grade prostatic intraepithelial neoplasia revealed ERalpha mRNA and protein expression in 28% and 11% of cases evaluated. Focal ER immunoreactivity was detected in a minority of low- to intermediate-grade adenocarcinoma. High-grade (primary Gleason grade 4 and 5) tumors revealed ER protein expression in 43% (62% respectively) of cases. The most significant ERalpha gene expression on mRNA and protein levels was observed in hormone refractory tumors and metastatic lesions, including lymph node and bone metastases. Results of the current study suggest that estrogens can affect prostatic cancerogenesis and neoplastic progression through an ER-mediated process in human prostate tissue.

Metastatic lesions from prostate cancer do not express oestrogen and progesterone receptors

Oestrogen receptors (ER) and progesterone receptors (PR) have been reported by several authors in the stromal cells of the human prostate. Controversial results exist on the expression of ER and PR in epithelial cells of the prostate. Some recent publications, in contrast to previous findings, have suggested that these receptors are also present in human prostate cancer cell lines derived from metastatic lesions. The expression of ER and PR in these cell lines has been re-examined to determine their presence in lymph node metastases from patients who did not receive any kind of endocrine therapy and in distant metastases obtained from patients who failed endocrine treatment. ER and PR expression in LNCaP, PC-3, and DU-145 cells was assessed by means of the reverse transcriptase-polymerase chain reaction, ligand binding assays, and immunohistochemistry. With all the techniques applied, the three cell lines were found to be negative for both ER and PR. Immunohistochemical analyses were performed in four lymph node metastases obtained at radical prostatectomy from patients who did not receive endocrine therapy and in 17 distant metastases obtained at palliative surgery from patients who failed endocrine therapy. All 21 metastases were negative for ER and PR on immunohistochemistry. These results do not support the recently developed concept that receptors for oestrogenic and progestagenic steroids are present in metastases from human prostate cancer.