Modulating effect of estrogen and testosterone on prostatic stromal cell phenotype differentiation induced by noradrenaline and doxazosin

Heterogenous induction of carcinoma-associated fibroblast-like differentiation in normal human prostatic fibroblasts by co-culturing with prostate cancer cells

In the tumor microenvironment, carcinoma-associated fibroblasts (CAFs) are considered to play a critical role in the promotion of tumorigenesis. However, the mechanisms that generate CAFs are not well elucidated. To understand how CAFs are generated during primary cancer progression, we investigated the biochemical characteristics of normal human prostate stromal cells (PrSC) co-cultured with human prostate cancer (PCa) cells in vitro. In primary cultures of human PCa-derived stromal cells (PCaSC-8 and PCaSC-9), expression of TNC, ACTA2, EGF, FGF7, and IGF1 mRNA was generally higher than PrSC but gene expression patterns were not uniform between PCaSC-8 and PCaSC-9 cells. Transforming growth factor β (TGFβ) and vascular endothelial growth factor (VEGF) protein levels in both PCaSC-8 and PCaSC-9 cells were generally higher than PrSC but levels of both secreted proteins were not same. When PrSCs were co-cultured with androgen-sensitive LNCaP cells or its sublines, androgen-low-sensitive E9 cells and androgen-insensitive AIDL cells, mRNA expression of IGF1 was significantly increased in all combinations. In contrast, expression of COL1A1, TNC, and ACTA2 mRNA was significantly increased only in LNCaP + PrSC and E9 + PrSC co-cultures. Protein production of VEGF was significantly increased only in LNCaP + PrSC and E9 + PrSC co-cultures. Increase of TGFβ protein was observed only in E9 + PrSC co-cultures. These biochemical characteristics of PrSC were partially recapitulated in TGFβ-treated PrSC. We have demonstrated that normal fibroblasts co-cultured with cancer cells become activated and exhibit biochemical characteristics of CAFs in a heterogenous manner. Our results suggest that heterogenous induction of CAF-like differentiation might be strongly dependent on biochemical characteristics of adjacent cancer cells.

Mepartricin long-term administration regulates steroid hormone and adrenergic receptor concentrations in the prostate of aged rats

Mepartricin is a semi-synthetic macrolide antibiotic developed as a drug for the treatment of benign prostatic hyperplasia (BPH) in human patients. In the present study, aged rats are used as an experimental model to evaluate the effects of mepartricin on circulating hormone concentrations and prostate receptor concentrations, to compare these possible effects with clinical findings observed in long-term treated dogs. Fifty-six aged male rats were randomly divided into four experimental groups treated orally with 0 (group 1), 2 mg (group 2), 5 mg (group 3) and 20 mg (group 4) mepartricin/kg of body weight. for 28 days respectively. Serum oestradiol and testosterone concentrations were measured by radio-immune-assays methods. Binding assays were used to measure the prostate concentrations of oestrogen receptors (ER), androgen receptors (AnR), alpha(1)-adrenergic receptor (alpha(1)-AR), and beta-adrenerergic receptor (beta-AR) subtypes. Mepartricin induced a significant reduction of prostate weight and serum oestradiol concentrations. Serum testosterone concentrations were unaffected. The treatment induced a significant down-regulation of ER concentrations (P < 0.05) and a significant up-regulation of AnR (P < 0.05) in rat prostate. Mepartricin induced a significant (P < 0.05) dose-dependent up-regulation of alpha(1)-AR and beta(2)-AR. In contrast, the concentration of beta(3)-ARs was significantly decreased (P < 0.05) in treated animals. The increase in prostate beta(2)-AR concentrations observed in subjects treated with mepartricin may be a favourable element in the evolution of BPH, because of the role exerted by these receptors in the control of prostatic smooth muscle relaxation. Curiously, beta(3)-AR concentrations were significantly reduced in treated animals. Data collected suggest that the prostatic beta-AR expression might be strongly influenced by oestrogen deprivation (mepartricin treatment); therefore, the combination of oestrogen suppression (mepartricin) and adrenergic suppression (alpha(1)-AR blockers) may be proposed as a possible nonhormonal therapeutic strategy for the treatment of benign prostatic hyperplasia in dogs.

Specialized stromal tumors of the prostate: a clinicopathologic study of 50 cases

Specialized stromal tumors of the prostate encompass stromal sarcoma and stromal tumors of uncertain malignant potential (STUMP). As a result of their relative rarity and lack of long-term follow-up, the prognosis of STUMP is unclear. We studied 50 cases of STUMP and stromal sarcoma with regard to their clinical presentation and follow-up. Patients ranged in age from 27 to 83 years (mean 58 years). The major presenting signs and symptoms were urinary obstructive symptoms (n=25), abnormal digital rectal exam (n=15), hematuria (n=7), hematospermia (n=1), and rectal dysfunction/fullness (n=3). An elevated prostate-specific antigen was either the sole or a compounding rationale for initial urologic examination and prostate biopsy in a subgroup of patients (n=11). The histology in the 36 cases of STUMP not associated with sarcoma were as follows: 25 composed of stroma with scattered cytologically atypical cells associated with benign glands; 8 resembling glandular-stromal hyperplasia but with hypercellular stroma; 6 with extensive myxoid stroma; and 1 with phyllodes pattern. Four of these cases had mixed patterns. Seven cases of STUMP were associated with sarcoma, either concurrently or subsequently. In another 7 cases, pure sarcomas were encountered: 3 low grade (LG) and 4 high grade (HG). In 19 STUMPs, the location of the lesion was determinable: 10 cases arose in the peripheral zone, 7 cases were located in the transition zone, and 2 cases seemed to involve both zones. In 3 of these cases, tumors were adherent to the rectum at the time of resection. There was no evidence of progression of disease for 14 STUMPs after biopsy, TUR, or enucleation where follow-up ranged from 0.3 to 14 years (mean 4.9 years). Five cases of STUMP showed local tumor growth: 1 case increased in size from 6 to 7.5 cm in 3 years and 4 cases recurred frequently necessitating multiple TURs of the prostate (n=2, n=3, n=3, n=3) over 1.1, 2, 7, and 8 years, respectively. Fourteen patients with STUMP underwent radical prostatectomy (RP) soon after diagnosis; of these, 12 were organ confined where the tumor size ranged from 0.7 to 7.5 cm (mean 2.7 cm); 2 cases with a history of a 28 g TUR and a 275 g enucleation showed no residual tumor in the RP specimen. Three cases were lost to follow-up. The histologic subtypes of STUMP did not correlate with the clinical behavior or likelihood of being associated with sarcoma. Two of the LG sarcomas locally invaded around the seminal vesicle, yet all of the LG sarcomas with follow-up were free of disease at 3, 13, 24, 25, 30, and 36 months. Of the 6 HG sarcomas with follow-up, 3 were free of disease at 3, 17, and 72 months. One man was alive with metastasis to the lung 10 months after RP, 1 man was alive at 280 months with multiple metastases, and another died of disease at 115 months. STUMPs can recur frequently, occur at a young age, often involve the peripheral zone where they can be adherent to the rectum requiring its removal, and can be associated with stromal sarcoma. Although STUMPs can be histologically misdiagnosed as nodular hyperplasia, it is important to recognize that these are neoplasms with unique local morbidity and malignant potential. Whereas LG stromal sarcomas can locally invade, HG sarcomas can metastasize and lead to death.

Sex steroids modulate α1-adrenoceptor-stimulated Ca2+ elevation in human cultured prostatic stromal cells

BACKGROUND

Benign prostatic hyperplasia is an age- and androgen-dependent condition of urethral compression caused by prostatic contractility and glandular enlargement. In this study we investigate whether testosterone, dihydrotestosterone and estradiol modulate the ability of human cultured prostatic stromal cells (HCPSCs) to respond to the adrenoceptor agonists, noradrenaline (30 microM) and phenylephrine (100 microM), the protein kinase C activating phorbol ester, phorbol diacetate (PDA, 10 microM), and the L-type Ca(2+) channel activator, (-)-Bay K8644 (Bay K, 10 microM) with elevations of intracellular Ca(2+) ([Ca(2+)](i)).

METHODS

Cells were loaded with the Ca(2+) sensitive fluorophore, FURA-2AM (10 microM) and changes in intracellular Ca(2+) determined before and 8-12 min after ligand addition.

RESULTS

Compared to steroid-free (SF) controls, the incubation of HCPSC with testosterone (30 and 300 pM) significantly increased responses to both noradrenaline and phenylephrine. Responses to Bay K were significantly reduced between 30 nM to 300 pM but responses to PDA were not greatly affected. Compared to SF the addition of estradiol (E(2), 100 pM) did not affect responses to phenylephrine. The concomitant addition of dihydrotestosterone (DHT) and E(2) (to give ratios from 1:1 to 1,000:1) elevated the responses to noradrenaline and phenylephrine at the extreme ranges. Responses to PDA and Bay K generally increased as DHT:E(2) approached unity.

CONCLUSIONS

These results indicate that sex steroids modulate the activities of HCPSCs through the regulation of both receptors and signal transduction processes.

Current models of human prostate contractility

1. The human prostate is a compact gland contributing to seminal fluid. With increasing age, most humans will develop benign prostatic hyperplasia, a condition of prostatic enlargement and contractility that leads to occlusion of the urethra. Over many years, investigators have used a variety of animal and cell culture models to elucidate some of the contractile and proliferative mechanisms that may be associated with the development of this condition. 2. This review briefly assesses the current state of knowledge of the mechanisms underlying human prostatic contractility and compares it with that of animal and cell culture models. It is not intended as a comprehensive methodological review, nor is it intended to indicate our preferences for either model. Our aim is to correlate findings from animal and cell culture models with the current understanding of human prostate contractility. 3. We hope that the present review will increase awareness of the suitability of the current models in developing our understanding of benign prostatic hyperplasia.

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.

Prostatic stem cells

Multipotent cells within the epithelial compartment, together with phenotypically 'plastic' mesenchyma cells (stromal stem cells), provide a repository of protected genetic information from which the structure, stability and functionality of the prostate gland can be maintained. However, mere preservation of cells in a non-dividing state is insufficient to provide the necessary reservoir of information from which the structure and function of the prostate gland can be retained or recreated. Rather, there is a constant dynamic interaction, at the level of information exchange, between stem cells (whether epithelial or mesenchymal) and their surrounding environment (both humoral and physical). Thus, with respect to epithelial stem cells, these reside within environmental 'niches' which allow their controlled and limited proliferation while preserving genomic integrity. Similar 'mesenchymal niches' are also predicted to occur, although not yet identified, thus providing the multipotent source from which the full spectrum of stromal phenotypes might be regenerated. Recent data from studies of the haematopoietic and hepato-biliary systems indicate that the potential scope of stem cells far exceeds the immediate phenotypic complement of those tissues within which they originate, being dependent upon their precise environment as well as their genomic integrity.

Effects of mepartricin on estradiol and testosterone serum levels and on prostatic estrogen, androgen and adrenergic receptor concentrations in adult rats

The effects induced by oral administration of 0, 5 and 20 mg of meparticin kg(-1)of body weight for 28 days (group 1, 2 and 3, respectively) upon prostatic estrogen, androgen, alpha(1)- and beta-adrenergic receptor concentrations and on estradiol and testosterone serum levels in adult male rats were studied. The effects produced by mepartricin treatments on the weight and dimension of the gland were investigated. Both mepartricin dosages induced significant decreases (P< 0.05) of the absolute and relative weights and of the dimensions of the prostate. A significant dose-dependent decrease (P< 0.05) in estradiol serum levels was observed in treated rats, whereas no significant modifications were found in testosterone serum levels. As far as prostatic steroid receptor concentrations were concerned, a significant (P< 0.05) decrease in estrogen receptor number was observed in both treated groups, whilst a significant increase (P< 0.05) of androgen receptor concentrations was recorded only in rats treated with 20 mg mepartricin kg(-1). Conversely, a dose-dependent up-regulation of both prostatic alpha(1)- and beta-AR was found. Data obtained suggest that the prostatic alpha(1)-AR expression may be strongly influenced by estrogen deprivation (mepartricin treatment), therefore the combination of estrogen suppression (mepartricin) and adrenergic suppression (alpha(1)-AR blockers) may be suggested as a possible pharmacotherapeutic strategy for the treatment of benign prostatic hyperplasia.