Regulation of prostatic growth and function by peptide growth factors

Inhibitory effects of Centella asiatica (L.) Urban on enlarged prostate through androgen receptor and PI3K/Akt signaling pathways

Centella asiatica (L.) Urban (C. asiatica) is a traditional herbal medicine that has been used for wound healing and anti-inflammation since ancient times. Various biological effects of C. asiatica ethanolic extract (CAE) were previously reported. However, in our previous study, C. asiatica aqueous extract (CAA) exhibited higher inhibitory activity on benign prostatic hyperplasia (BPH) than CAE. Therefore, the aim of this study was to investigate the effect of CAA on BPH, and elucidate the inhibitory mechanism through in vitro and in vivo experiments as well as metabolite analysis of CAA. A BPH rat model was induced by daily subcutaneous injection of testosterone propionate (TP, 3 mg kg^-1) dissolved in corn oil for 4 weeks after castration. The experimental group, the CAA treatment group, was orally administered CAA (100 mg kg^-1) for 4 weeks while inducing prostatic hyperplasia. Saw palmetto extract (Saw, 100 mg kg^-1) and Finasteride (Fi, 1 mg kg^-1) were used as positive controls and were administered orally for 4 weeks. CAA significantly inhibited androgen receptor signaling related factors overexpressed by dihydrotestosterone (DHT) treatment in prostate cell lines. Afterwards, the testosterone-induced BPH model was used to verify the alleviation efficacy of CAA in prostatic hyperplasia. Prostate size and the thickness of the prostate tissue epithelium were significantly decreased in the group treated with CAA compared to those in the BPH group. The results of protein expression in the prostate tissue confirmed that CAA inhibited androgen receptor signaling in BPH and decreased the expression of growth factors. Moreover, CAA suppressed the expression of the PI3K/Akt pathway and cell proliferation-related factors compared to the BPH group. Taken together, these results indicate that CAA improves the inhibitory efficacy of BPH by inhibiting the androgen receptor and PI3K/Akt pathways, suggesting that CAA may be a promising candidate for biopharmaceutical formulations of BPH.

Origanum majorana L. Extract Attenuated Benign Prostatic Hyperplasia in Rat Model: Effect on Oxidative Stress, Apoptosis, and Proliferation

Benign prostatic hyperplasia (BPH) is a widespread androgenic illness influencing elderly men. It is distinguished by prostatic epithelial and stromal muscle cell proliferation. Inflammation, oxidative stress, and apoptosis have all been interrelated to the development of BPH. Marjoram (Origanum majorana L.) is a herb with reported antiproliferative, proapoptotic, and antioxidative properties, which have not yet been studied in relation to BPH. Consequently, in this work, an ethanolic extract of O. majorana was prepared in two doses (250 and 500 mg/kg/day) to be injected into castrated rats after induction of a testosterone-BPH model. Testosterone propionate (TP) was subcutaneously injected (0.5 mg/kg/day) for one week after castration to induce BPH. Forty adult Wistar male rats were randomly allocated into five groups: control, BPH model, high and low O. majorana doses (250, 500 mg/kg/day), and finasteride (FN) (0.8 mg/kg/day) as a positive control. Treatment was continued with drugs/normal saline for 28 days. Rat’s body and prostate were weighed, prostate index (PI) and % of prostate growth inhibition were calculated, serum dihydrotestosterone (DHT), prostatic content of superoxide dismutase (SOD), catalase (CAT), total antioxidant capacity (TAC), and malondialdehyde (MDA), DN damage, histopathological changes, immune expression of proliferating cell nuclear antigen (PCNA), caspase-3, α-SMA, and TGF-β1 were assessed. In addition, molecular quantitative PCR and ELISA analyses were performed to identify the expression of mRNAs and related proteins of both caspase-3 and TGF-β1 in prostate tissue from O. majorana-treated and untreated groups. Rats with BPH had significantly higher prostate weights and PI, higher DHT, DNA damage (8-hydroxyguanine, 8-OH-dG), and MDA levels with prominent PCNA, α-SMA, and TGF-β expression, but lower SOD, CAT, and TAC activity and caspase-3 expression. O. majorana (250 and 500 mg/kg/day)-treated groups revealed a decrease in prostate weights and PI, lower levels of DHT, suppressed oxidative stress, reduced tissue proliferation and fibrosis, and restored antioxidant and proapoptotic activity. Additionally, quantitative PCR and ELISA analysis showed that treatment with O. majorana significantly upregulated the expression of caspase-3 and downregulated the expression of TGF-β in prostate tissues of BPH rats. The data were confirmed by the immunohistological reactivity of these targeted markers in the prostate tissues. These effects were more significant with O. majorana 500 mg/mL/rat. In conclusion, the current study indicates the efficient use of O. majorana in the treatment of testosterone-induced BPH through its antiproliferative, proapoptotic, and antioxidative mechanisms.

The pathological growth of the prostate gland in atherogenic contexts

The human prostate is an androgen-dependent gland where an imbalance in cell proliferation can lead to benign prostatic hyperplasia (BPH), which results in voiding lower urinary tract symptoms in the elderly. In the last decades, novel evidence has suggested that BPH might represent an element into the wide spectrum of disorders conforming the Metabolic Syndrome (MS). The dyslipidemic state and the other atherogenic factors of the MS have been shown to induce, maintain and/or aggravate the pathological growth of different organs, with data regarding the prostate being still limited. We here review the available epidemiological and experimental studies about the association of BPH with dyslipidemias. In particular, we have focused on Oxidized Low-Density Lipoproteins (OxLDL) as a potential trigger for vascular disease and cellular proliferation in atherogenic contexts, analyzing their putative molecular mechanisms, including the induction of specific extracellular vesicles (EVs)-derived miRNAs. In addition to the epidemiological evidence, OxLDL is proposed to play a fundamental role in the upregulation of prostatic cell proliferation by activating the Rho/Akt/p27^Kip1 pathway in atherogenic contexts. miR-21, miR-141, miR-143, miR-145, miR-155, and miR-221 would be involved in the transcription of genes related to the proliferative process. Although much remains to be investigated regarding the impact of OxLDL, its receptors, and molecular mechanisms on the prostate, it is clear that EVs and miRNAs represent a promising target for proliferative pathologies of the prostate gland.

The Roles of Stroma-Derived Chemokine in Different Stages of Cancer Metastases

The intricate interplay between malignant cells and host cellular and non-cellular components play crucial role in different stages of tumor development, progression, and metastases. Tumor and stromal cells communicate to each other through receptors such as integrins and secretion of signaling molecules like growth factors, cytokines, chemokines and inflammatory mediators. Chemokines mediated signaling pathways have emerged as major mechanisms underlying multifaceted roles played by host cells during tumor progression. In response to tumor stimuli, host cells-derived chemokines further activates signaling cascades that support the ability of tumor cells to invade surrounding basement membrane and extra-cellular matrix. The host-derived chemokines act on endothelial cells to increase their permeability and facilitate tumor cells intravasation and extravasation. The tumor cells-host neutrophils interaction within the vasculature initiates chemokines driven recruitment of inflammatory cells that protects circulatory tumor cells from immune attack. Chemokines secreted by tumor cells and stromal immune and non-immune cells within the tumor microenvironment enter the circulation and are responsible for formation of a "pre-metastatic niche" like a "soil" in distant organs whereby circulating tumor cells "seed' and colonize, leading to formation of metastatic foci. Given the importance of host derived chemokines in cancer progression and metastases several drugs like Mogamulizumab, Plerixafor, Repertaxin among others are part of ongoing clinical trial which target chemokines and their receptors against cancer pathogenesis. In this review, we focus on recent advances in understanding the complexity of chemokines network in tumor microenvironment, with an emphasis on chemokines secreted from host cells. We especially summarize the role of host-derived chemokines in different stages of metastases, including invasion, dissemination, migration into the vasculature, and seeding into the pre-metastatic niche. We finally provide a brief description of prospective drugs that target chemokines in different clinical trials against cancer.

Piceatannol Attenuates Testosterone-Induced Benign Prostatic Hyperplasia in Rats by Modulation of Nrf2/HO-1/NFκB Axis

Benign prostatic hyperplasia (BPH) is a serious illness affecting middle-aged and elderly male patients. It is a complication of several diseases including metabolic syndrome. BPH has been associated with inflammation and increased oxidative stress in prostatic tissues. Piceatannol (PIC) is an active natural polyhydroxylated stilbene found in many plants. It has profound anti-inflammatory as well as antioxidant activities. However, it suffers relatively poor pharmacokinetic properties. Nanoformulation is an acknowledged approach to improve PIC bioavailability. The goal was to evaluate the ability of PIC in preventing testosterone-induced benign prostatic hyperplasia in rats. PIC was prepared in a self-nanoemulsifying drug delivery system (SNEDDS). Animals were placed into seven groups: 1) control (vehicle), 2) PIC SNEDDS (20 mg/kg), 3) testosterone (3 mg/kg), 4) testosterone + PIC SNEDDS (5 mg/kg), 5) testosterone + PIC (10 mg/kg), 6) testosterone + PIC SNEDDS (20 mg/kg) and 7) testosterone + finasteride (5 mg/kg). Testosterone was injected SC while PIC SNEDDS and finasteride were given orally. All treatments were given once daily, 5 days/week for four consecutive weeks. PIC administration ameliorated increased prostate weights and indices in addition to histopathological alterations. Further it inhibited accumulation of lipid peroxidation, depletion of glutathione (GSH) and exhaustion of catalase (CAT). PIC SNEDDS exhibited anti-proliferative activities as demonstrated by the inhibition of cyclin D1 protein expression and Bcl2 mRNA expression in addition to enhancement of Bax mRNA expression and caspase-3 content. Immunohistochemically, PIC SNEDDS protected against the testosterone-induced increased expression of tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), nuclear factor kappa B (NFκB) and also offered protection against the decline in Nrf2 expression. Further, a significant enhancement of Nfe212 and Homx1 mRNA expression was detected in PIC SNEDDS-treated animals in comparison to the testosterone group. Conclusively, PIC prepared in SNEDDS protects against experimentally induced BPH via modulation of, at least partly, Nrf2/HO-1/NFκB axis.

Immunomodulatory effect of diallyl sulfide on experimentally-induced benign prostate hyperplasia via the suppression of CD4+T/IL-17 and TGF-β1/ERK pathways

Benign prostatic hyperplasia (BPH) is a nonmalignant enlargement of the prostate common in older men. Diallyl sulfide (DAS), a major component of garlic, has been reported to possess antioxidant, anti-inflammatory, and antiproliferative effects. However, the underlying protective immunomodulatory mechanism of DAS on BPH remains vague. Herein, experimental BPH was induced in rats by daily subcutaneous injection of testosterone propionate (TP) (3 mg/kg, s.c.) for 4 weeks. In parallel, finasteride (Fin) (5 mg/kg, p.o) or DAS (50 mg/kg, p.o.) was administered orally during BPH induction. TP-induced histological alterations and the immune-inflammatory cascade. On the other hand, DAS or Fin administration alleviated all abnormalities induced testosterone. Fin and DAS administration markedly reduced prostate weight by 53% with Fin, and by 60% with DAS. Moreover, serum testosterone and DHT were reduced by 55% and 52%, respectively, with Fin and by 68% and 75%, respectively, with DAS, in concordance with decreased protein expression of androgen receptor (AR), and prostate-specific antigen (PSA). Furthermore, both regime lessen immune-inflammatory milieu, as evidenced by decrease CD4+ T-cells protein expression and associated inflammatory cytokines. Concomitantly, Fin and DAS exhibited marked mitigation in insulin-like growth factor-1 (IGF-1), transforming growth factor-beta1 (TGF-β1), and phosphorylated extracellular signal-regulated kinase (ERK1/2) signaling. Besides alleviating oxidative stress by 53% and 68% in prostatic MDA and by 27% and 7% in prostatic iNOS with Fin and DAS, respectively. In conclusion, this work highlighted a potential therapeutic approach of DAS as a dietary preventive agent against BPH via its anti-inflammatory and immunomodulatory effect along with suppression of the ERK pathway.

Effect of gold nanoparticles treatment on the testosterone-induced benign prostatic hyperplasia in rats

Background: Gold nanoparticles (AuNps) are promising agents for prostate cancer therapy. Herein, the in vivo effects of 20 and 50 nm sized AuNps on experimentally induced benign prostatic hyperplasia (BPH) was examined.

Materials and methods: Adult male rats were divided into four groups (n=6–8 each). A negative control group and three groups were injected daily with testosterone (3 mg/kg/subcutaneously) to induce BPH. Animals receiving testosterone were randomized to untreated BPH group and two BPH groups which were treated intraperitoneally with 20 and 50 nm AuNps (5 mg/kg/daily) in addition to testosterone. After three weeks, histopathological changes and serum levels of testosterone and dihydrotestosterone (DHT) were analyzed. In addition, the prostate tissue levels of transforming growth factor-β₁ (TGF-β₁), vascular endothelial growth factor-a (VEGF-A) and interleukin-6 (IL-6) were measured using ELISA.

Results: There were significant increases in the prostate weight/body weight ratio, serum testosterone and DHT and in the prostate tissue content of TGF-β₁, IL-6 and VEGF-A in the untreated BPH group. histological examination showed morphological abnormalities with more proliferation in the glandular epithelial and stromal area and with abundant epithelial papillary folds in the BPH group. Simultaneous administration of 50 nm AuNps with testosterone tended to increase the prostate weight/body weight ratio and increase the tissue level of IL-6 in compared to the BPH group. Conversely, treatment with 20 nm AuNps significantly reduced the elevated tissue content of TGF-β₁, IL-6, and VEGF-A. Histopathological examination also showed that 20 nm but not the 50 nm AuNps administration ameliorates testosterone-induced prostatic hyperplasia.

Conclusions: In experimentally induced BPH, AuNps can inhibit the progression of BPH in a size-dependent manner. while 20 nm AuNps ameliorate BPH by its inhibitory effects on the prostatic cell proliferation, inflammation and angiogenesis, the 50 nm AuNps could potentially exacerbate the development of BPH in rats, mainly through enhancing the inflammatory process.

Berberine Improves Benign Prostatic Hyperplasia via Suppression of 5 Alpha Reductase and Extracellular Signal-Regulated Kinase in Vivo and in Vitro

Benign prostate hyperplasia (BPH) is a common disease in elderly men, characterized by proliferated prostate and urinary tract symptoms. The hormonal cascade starting by the action of 5-alpha-reductase (5AR) is known to be one of the pathways responsible for the pathogenesis of BPH. Present investigation evaluated the capacity of berberine (BBR), a nature-derived compound abundant in Coptis japonica, in testosterone-induced BPH rats. Experimental BPH was induced by inguinal injection with testosterone propionate (TP) for 4 weeks. BBR or finasteride, a 5AR inhibitor as positive control, was treated for 4 weeks during BPH. BPH induced by TP evoked weight gaining and histological changes of prostate and BBR treatment improved all the detrimental effects not only weight reduction and histological changes but also suppression of prostate-specific antigen (PSA), which is elevated during BPH. Additionally, BBR suppressed TP-associated increase of 5AR, androgen receptor (AR) and steroid coactivator-1 (SRC-1), the key factors in the pathogenesis of BPH. To evaluate the underlying molecular mechanisms responsible for beneficial effects of BBR, we investigated whether these effects were associated with the mitogen-activated protein kinase pathway. BPH induced by TP showed increased phosphorylation of extracellular signal-regulated kinase (ERK), whereas this was suppressed by BBR treatment. On the other hand, c-jun-N-terminal kinase (JNK) and p38 mitogen-activated protein kinase was not changed in BPH rats. In in vitro study using RWPE-1 cells, a human prostate epithelial cell line. TP increased cell proliferation and BPH-related key factors such as PSA, AR, and 5AR in RWPE-1 cells, and those factors were significantly decreased in the presence of BBR. Furthermore, these proliferative effects in RWPE-1cells were attenuated by treatment with U0126, an ERK inhibitor, confirming BBR can relieve overgrowth of prostate via ERK-dependent signaling. The cotreatment of U0126 and BBR did not affect the change of 5AR nor proliferation compared with U0126 alone, suggesting that the effect of BBR was dependent on the action of ERK. In conclusion, this study shows that BBR can be used as a therapeutic agent for BPH by controlling hyperplasia of prostate through suppression of ERK mechanism.

Potential repositioning of GV1001 as a therapeutic agent for testosterone‑induced benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is one of the leading causes of male reproductive disorders. Therapeutic agents currently in use have severe side effects; therefore, alternative drugs that exhibit improved therapeutic activity without side effects are required. The present study investigated the protective effect of GV1001 against testosterone‑induced BPH in rats. BPH in castrated rats was established via daily subcutaneous (s.c.) injections of testosterone propionate (TP, 3 mg/kg) dissolved in corn oil for 4 weeks. GV1001 (0.01, 0.1 and 1 mg/kg, s.c.) was administered 3 times per week for 4 weeks, together with TP (3 mg/kg) injection. The rats were sacrificed on the last day of treatment, and their prostates were excised and weighed for biochemical and histological studies. Serum levels of testosterone and dihydrotestosterone (DHT) were also measured. In rats with TP‑induced BPH, a significant increase in prostate weight (PW) and prostatic index (PI), accompanied by a decrease in antioxidant enzyme activity, was observed. Histological studies revealed clearly enlarged glandular cavities in rats with BPH. GV1001 (0.01 and 0.1 mg/kg) treatment significantly decreased PW and PI in rats with TP‑induced BPH. In addition, GV1001 demonstrated a potent inhibitory effect on 5α‑reductase in prostate. The present data suggest that the protective role of GV1001 against testosterone‑induced BPH is closely associated with its antioxidant potential. Additional studies are required to identify the mechanisms by which GV1001 protects against BPH to determine its clinical application.

Cynanchum wilfordii Ameliorates Testosterone-Induced Benign Prostatic Hyperplasia by Regulating 5α-Reductase and Androgen Receptor Activities in a Rat Model

Benign prostatic hyperplasia (BPH) is characterized by uncontrolled proliferation of the prostate gland. Cynanchum wilfordii has been reported to improve sexual behavior in male rats. In this study, we investigated the protective effect of an aqueous extract of C. wilfordii (CWW) against BPH development in a testosterone-induced BPH rat model. The rats were divided into the following six groups: sham/vehicle; BPH/vehicle; BPH/finasteride; and three CWW doses (50, 100, and 200 mg/kg). After a 4-week treatment with CWW, the rats were euthanized at scheduled times, and their prostates were weighed, followed by a histopathological examination. Prostate growth inhibition rates in rats administered CWW 50, 100, and 200 mg/kg were 54.5%, 51.8%, and 50.1%, respectively. The BPH/CWW group showed decreased serum testosterone and dihydrotestosterone (DHT) levels compared to the BPH/vehicle group. Furthermore, the BPH/CWW group showed reduced prostate testosterone and DHT levels compared to the BPH/vehicle group. Mechanistically, the reverse transcription-polymerase chain reaction revealed downregulated mRNA expression levels of the androgen receptor, 5α-reductase, and B-cell lymphoma-2 (Bcl-2) in the BPH/CWW200 group compared with those in the testosterone-induced groups. In conclusion, these findings show the effectiveness of CWW in slowing the progression of testosterone-induced BPH in rats.

Ginger Ingredients Alleviate Diabetic Prostatic Complications: Effect on Oxidative Stress and Fibrosis

Prostatic complications are common in patients with diabetes. This study investigated the effect of different ginger ingredients: zingerone, geraniol, and 6-gingerol on the prostate in diabetic rats. Diabetes was induced in Wistar rats by streptozotocin intraperitoneal injection (50 mg/kg), and the rats were left for 10 weeks to develop prostatic complications. In diabetic treated groups, rats received daily oral zingerone, geraniol, and 6-gingerol in doses of 20, 200, and 75 mg/kg, respectively, in the last 8 weeks. Treatment with the compounds caused changes in the ventral prostate of diabetic animals as indicated by the columnar ductal epithelium and dense secretions. There was an amelioration of oxidative stress as evidenced by the lowering of prostate malondialdehyde and elevating prostate oxidized to reduced glutathione (GSH/GSSG) ratios by geraniol and 6-gingerol. None of the three ginger ingredients affected the hyperglycemia, reduction in body weight gain, and testosterone deficiency seen in diabetic animals. Interleukin-1β and interleukin-6 levels remained unchanged. However, zingerone and geraniol ameliorated the fibrosis in diabetic prostate through suppressing the elevated prostate transforming growth factor beta 1 (TGFβ1) and collagen IV. Therefore, ginger ingredients could be beneficial in alleviating diabetic prostatic complications through suppressing oxidative stress and tissue fibrosis.

Review of Prostate Anatomy and Embryology and the Etiology of Benign Prostatic Hyperplasia

Prostate development follows a common pattern between species and depends on the actions of androgens to induce and support ductal branching morphogenesis of buds emerging from the urogenital sinus. The human prostate has a compact zonal anatomy immediately surrounding the urethra and below the urinary bladder. Rodents have a lobular prostate with lobes radiating away from the urethra. The human prostate is the site of benign hyperplasia, prostate cancer, and prostatitis. The rodent prostate has little naturally occurring disease. Rodents can be used to model aspects of human benign hyperplasia, but care should be taken in data interpretation and extrapolation to the human condition.

Gene Polymorphism-related Individual and Interracial Differences in the Outcomes of Androgen Deprivation Therapy for Prostate Cancer

Among patients with prostate cancer, the prognosis after androgen deprivation therapy differs significantly among individuals and among races; however, the reasons underlying these differences are poorly understood. Several single nucleotide polymorphisms in genes associated with prostate cancer progression or castration resistance might serve as the host factor that influences prognosis and, thus, accounts for these individual and racial gaps in treatment outcomes. Accordingly, single nucleotide polymorphisms associated with treatment outcomes could be used as predictive and/or prognostic biomarkers for patient stratification and to identify personalized treatment and follow-up protocols. The present review has summarized the genetic polymorphisms that have been reported to associate with androgen deprivation therapy outcomes among patients with prostate cancer and compared the allele frequencies among different ethnic groups.

Epidermal Growth Factor Receptor Status in Circulating Tumor Cells as a Predictive Biomarker of Sensitivity in Castration-Resistant Prostate Cancer Patients Treated with Docetaxel Chemotherapy

Objective: We examined whether epidermal growth factor receptor (EGFR) expression in circulating tumor cells (CTCs) can be used to predict survival in a population of bone-metastatic castration-resistant prostate cancer (mCRPC) patients treated with docetaxel chemotherapy. Methods: All patients with mCRPC who had experienced treatment failure with androgen-deprivation therapy and had received docetaxel chemotherapy were eligible. CTCs and EGFR expression in CTCs were enumerated with the CellSearch System in whole blood. This system is a semi-automated system that detects and enriches epithelial cells from whole blood using an EpCAM antibody-based immunomagnetic capture. In addition, the EGFR-positive CTCs were assessed using CellSearch^® Tumor Phenotyping Reagent EGFR. Results: The median CTC count at baseline before starting trial treatment was eight CTCs per 7.5 mL of blood (range 0–184). There were 37 patients (61.7%) who had ≥5 CTCs, with median overall survival of 11.5 months compared with 20.0 months for 23 patients (38.3%) with <5 CTCs (p < 0.001). A total of 15 patients (40.5%, 15/37) with five or more CTCs were subjected to automated immunofluorescence staining and cell sorting for EGFR protein. Patients with EGFR-positive CTCs had a shorter overall survival (OS) (5.5 months) than patients with EGFR-negative CTCs (20.0 months). CTCs, EGFR-positive CTCs, and alkaline phosphatase (ALP) were independent predictors of overall survival time (p = 0.002, p < 0.001, and p = 0.017, respectively). Conclusion: CTCs may be an independent predictor of OS in CRPC treated with docetaxel chemotherapy. The EGFR expression detected in CTCs was important for assessing the response to chemotherapy and predicting disease outcome.

Epidermal Growth Factor Receptor in Prostate Cancer Derived Exosomes

Exosomes proteins and microRNAs have gained much attention as diagnostic tools and biomarker potential in various malignancies including prostate cancer (PCa). However, the role of exosomes and membrane-associated receptors, particularly epidermal growth factor receptor (EGFR) as mediators of cell proliferation and invasion in PCa progression remains unexplored. EGFR is frequently overexpressed and has been associated with aggressive forms of PCa. While PCa cells and tissues express EGFR, it is unknown whether exosomes derived from PCa cells or PCa patient serum contains EGFR. The aim of this study was to detect and characterize EGFR in exosomes derived from PCa cells, LNCaP xenograft and PCa patient serum. Exosomes were isolated from conditioned media of different PCa cell lines; LNCaP xenograft serum as well as patient plasma/serum by differential centrifugation and ultracentrifugation on a sucrose density gradient. Exosomes were confirmed by electron microscopy, expression of exosomal markers and NanoSight^™ analysis. EGFR expression was determined by western blot analysis and ELISA. This study demonstrates that exosomes may easily be derived from PCa cell lines, serum obtained from PCa xenograft bearing mice and clinical samples derived from PCa patients. Presence of exosomal EGFR in PCa patient exosomes may present a novel approach for measuring of the disease state. Our work will allow to build on this finding for future understanding of PCa exosomes and their potential role in PCa progression and as minimal invasive biomarkers for PCa.

Increase in prostate stem cell antigen expression in prostatic hyperplasia induced by testosterone and 17β-estradiol in C57BL mice

Estradiol (E2) is known to act synergistically with testosterone (T) for the development of prostatic hyperplasia in rats and dogs, but murine prostate is less responsive to hormonal stimulation. However, a recent study revealed that the combined administration of E2 and T induced prostatic hyperplasia with bladder outlet obstruction in C57BL mice. To understand the mechanisms underlying the hormonal induction of prostatic hyperplasia, the expression of growth factors and their receptors, androgen receptor, estrogen receptor (ER), and prostatic secretory proteins was investigated. Ten-week-old male C57BL mice were treated with T (30mg) or T+E2 (0.5mg) for 10 weeks, and prostatic lobes were dissected and subjected to quantitative RT-PCR and immunoblotting analysis. T administration appeared to induce glandular prostatic growth, while with T+E2 administration this growth was greater and accompanied by extreme bladder enlargement. The expression of prostate stem cell antigen (PSCA) mRNA and protein was increased in prostate tissue in the T group. The combined administration of E2 with T prominently enhanced PSCA expression, along with increased insulin growth factor 1 mRNA levels and decreased estrogen receptor β mRNA expression. The synergistic effect of E2 on the expression of PSCA suggests that this protein may play an important role in the hormone-induced development of prostatic hyperplasia.

Checkpoint Kinase 2 Negatively Regulates Androgen Sensitivity and Prostate Cancer Cell Growth

Prostate cancer is the second leading cause of cancer death in American men, and curing metastatic disease remains a significant challenge. Nearly all patients with disseminated prostate cancer initially respond to androgen deprivation therapy (ADT), but virtually all patients will relapse and develop incurable castration-resistant prostate cancer (CRPC). A high-throughput RNAi screen to identify signaling pathways regulating prostate cancer cell growth led to our discovery that checkpoint kinase 2 (CHK2) knockdown dramatically increased prostate cancer growth and hypersensitized cells to low androgen levels. Mechanistic investigations revealed that the effects of CHK2 were dependent on the downstream signaling proteins CDC25C and CDK1. Moreover, CHK2 depletion increased androgen receptor (AR) transcriptional activity on androgen-regulated genes, substantiating the finding that CHK2 affects prostate cancer proliferation, partly, through the AR. Remarkably, we further show that CHK2 is a novel AR-repressed gene, suggestive of a negative feedback loop between CHK2 and AR. In addition, we provide evidence that CHK2 physically associates with the AR and that cell-cycle inhibition increased this association. Finally, IHC analysis of CHK2 in prostate cancer patient samples demonstrated a decrease in CHK2 expression in high-grade tumors. In conclusion, we propose that CHK2 is a negative regulator of androgen sensitivity and prostate cancer growth, and that CHK2 signaling is lost during prostate cancer progression to castration resistance. Thus, perturbing CHK2 signaling may offer a new therapeutic approach for sensitizing CRPC to ADT and radiation.

Metformin Attenuates Testosterone-Induced Prostatic Hyperplasia in Rats: A Pharmacological Perspective

Benign prostatic hyperplasia (BPH) is uncontrolled proliferation of prostate tissue. Metformin, a widely prescribed anti-diabetic agent, possesses anticancer activity through induction of apoptotic signaling and cell cycle arrest. This study aimed to investigate the protective effect of metformin against experimentally-induced BPH in rats. Treatment with 500 and 1000 mg/kg metformin orally for 14 days significantly inhibited testosterone-mediated increase in the prostate weight & prostate index (prostate weight/body weight [mg/g]) and attenuated the pathological alterations induced by testosterone. Mechanistically, metformin significantly protected against testosterone-induced elevation of estrogen receptor-α (ER-α) and decrease of estrogen receptor-β (ER-β) expression, with no significant effect of androgen receptor (AR) and 5α-reductase expression. It decreased mRNA expression of IGF-1 and IGF-1R and protein expression ratio of pAkt/total Akt induced by testosterone. Furthermore, it significantly ameliorated testosterone–induced reduction of mRNA expression Bax/Bcl-2 ratio, P21 and phosphatase and tensin homolog (PTEN) and AMPK [PT-172] activity. In conclusion, these findings elucidate the effectiveness of metformin in preventing testosterone-induced BPH in rats. These results could be attributed, at least partly, to its ability to enhance expression ratio of ER-β/ER-α, decrease IGF-1, IGF-1R and pAkt expressions, increase P21, PTEN, Bax/Bcl-2 expressions and activate AMPK with a subsequent inhibition of prostate proliferation.

Cooperative effects of EGF, FGF, and TGF-β1 in prostate stromal cells are different from responses to single growth factors

AIMS

Stromal growth is critical for prostate enlargement during benign prostatic hyperplasia (BPH). While responses of prostate cells to single growth factors have been well characterized, responses to multiple growth factors at once are poorly understood. Here, we examined the effects of combinations between epidermal growth factor (EGF), fibroblast growth factor (FGF), and transforming growth factor-β1 (TGF-β1) in human prostate stromal cells.

MAIN METHODS

EGF, FGF, and TGF-β1 were applied to WPMY-1 cells, an immortalized, non-malignant line of stromal cells from the human prostate. Hypertrophic responses were assessed by protein/DNA ratio, and cyclin D1 mRNA by RT-PCR. Expression of EGF, FGF, and TGF-β1 and their receptors in human prostate tissue was analyzed by RT-PCR, Western blot, and fluorescence staining.

KEY FINDINGS

Hypertrophic responses to single growth factors and combinations were similar. Combinations showed additive effects on cyclin D1 mRNA. Combination of EGF with TGF-β1, but not EGF or TGF-β1 alone, caused assembly of cells to a new two-dimensional structure, being characterized by dense aggregates connected by branches of few cells. EGF and TGF-β1 were detected together in human prostates. Receptors for EGF and TGF-β colocalized on stromal cells in human prostates.

SIGNIFICANCE

Responses of prostate stromal cells to combinations of EGF, FGF, and TGF-β1 may be quantitatively different, qualitatively different, or similar to responses to single growth factors. The combination of EGF and TGF-β1, but not EGF or TGF-β1 alone, induces aggregation of prostate stromal cells, which may be relevant for morphogenesis.

Stromal nodules in benign prostatic hyperplasia: morphologic and immunohistochemical characteristics

BACKGROUND

One hundred forty nine stromal nodules (SNs) from transurethral resection of benign prostatic hyperplasia specimens in 39 patients (57-85 years with mean of 70.9) were investigated to characterize the SNs and to outline the etiopathogenesis of solitary fibrous tumors (SFTs) and gastrointestinal stromal tumors (GISTs) of prostate by immunohistochemistry performed on tissue microarray sections.

METHODS

Antibodies used included smooth muscle actin, desmin, vimentin, and S-100 protein for subtyping, vascular endothelial growth factor, insulin-like growth factor-1, fibroblast growth factor, and TGF-ß as growth factors; CD133, c-KIT, CD34, and CD44 as stem cell markers; and estrogen (ER), progesterone (PR), and androgen receptor (AR) as hormone receptors.

RESULTS

SNs were classified into four subtypes: (1) immature mesenchymal (n = 7, 4.7%); (2) fibroblastic (n = 74, 49.7%); (3) fibromuscular (n = 53, 35.6%); and (4) smooth muscular (n = 15, 10.1%) types. There were linear trends of the expression of all growth factors (VEGF, IGF-1, FGF, TGF-ß), but only CD44 stem cell marker and AR hormone receptor as maturation progressed from immature mesenchymal to smooth muscular type (Ptrend  < 0.05). S-100, c-KIT, and ER were not expressed in any types of SNs. CD34 was positive in 55% of the SNs (82/149).

CONCLUSIONS

The data suggest that AR and growth factors are important factors for maturation of SNs, but not influenced by the administration of 5-alpha reductase inhibitor (5ARI). Although the cells comprising the SNs seem to be not associated with the origin of prostatic GISTs, there is a possibility of a tentative link of SFTs arising from SNs of the prostate.

Stromal androgen receptor in prostate development and cancer

The androgen receptor (AR) in stromal cells contributes significantly to the development and growth of prostate during fetal stages as well as during prostate carcinogenesis and cancer progression. During prostate development, stromal AR induces and promotes epithelial cell growth, as observed from tissue recombinant and mouse knockout studies. During prostate carcinogenesis and progression, the stromal cells begin to lose AR expression as early as at the stage of high-grade prostatic intraepithelial neoplasia. The extent of loss of stromal AR is directly proportional to the degree of differentiation (Gleason grade) and progression of prostate cancer (PCa). Co-culture studies suggested that stromal AR inhibits the growth of malignant epithelial cells, possibly through expression of certain paracrine factors in the presence of androgens. This functional reversal of stromal AR, from growth promotion during fetal prostate development to mediating certain growth-inhibiting effects in cancer, explains to some extent the reason that loss of AR expression in stromal cells may be crucial for development of resistance to androgen ablation therapy for PCa. From a translational perspective, it generates the need to re-examine the current therapeutic options and opens a fundamental new direction for therapeutic interventions, especially in advanced PCa.

Inhibitory effects by ayurvedic plants on prostate enlargement induced in rats

Background:

Ayurveda recommends several plants and plant preparation for conditions of urogenital disorders as per its principles. Objectives: Ayurvedic plants Tamala (Cinnamomum tamala); Daruhalad (Berberis aristata); Ativish (Aconitum heterophyllum) were studied for mechanisms of prostatic hyperplasia induced in rats.

Materials and Methods:

Prostatic enlargement was induced in castrated rats by testosterone injection s.c. for 21 days and simultaneously plants were dosed orally daily. On day 22 rats were sacrificed and prostate was removed; weight and volume of prostate was measured; histopathology performed. Inflammation was induced by injecting carrageenan in rat hind paw and inhibition was studied by measuring rat paw oedema at different time points.

Results:

Tamala showed significant effect where it reduced prostatic enlargement and improved hyperplastic changes, while Daruhalad and Ativisha did not show any significant effect. All of them showed mild to moderate anti-inflammatory activity.

Conclusion:

Study concludes that Tamala may benefit in prostate disorder by virtue of inhibition of androgen mechanisms in prostate and modulating inflammatory mediators in prostate. Daruhalad and Ativisha did not show any effect in this model of prostate enlargement while the anti-inflammatory effect may propose one of the useful properties when included in various formulations.

Immunomodulatory effect of red onion (Allium cepa Linn) scale extract on experimentally induced atypical prostatic hyperplasia in Wistar rats

Red onion scales (ROS) contain large amounts of flavonoids that are responsible for the reported antioxidant activity, immune enhancement, and anticancer property. Atypical prostatic hyperplasia (APH) was induced in adult castrated Wistar rats by both s.c. injection of testosterone (0.5 mg/rat/day) and by smearing citral on shaved skin once every 3 days for 30 days. Saw palmetto (100 mg/kg) as a positive control and ROS suspension at doses of 75, 150, and 300 mg/kg/day were given orally every day for 30 days. All medications were started 7 days after castration and along with testosterone and citral. The HPLC profile of ROS methanolic extract displayed two major peaks identified as quercetin and quercetin-4′-β-O-D-glucoside. Histopathological examination of APH-induced prostatic rats revealed evidence of hyperplasia and inflammation with cellular proliferation and reduced apoptosis Immunohistochemistry showed increased tissue expressions of IL-6, IL-8, TNF-α, IGF-1, and clusterin, while TGF-β1 was decreased, which correlates with the presence of inflammation. Both saw palmetto and RO scale treatment have ameliorated these changes. These ameliorative effects were more evident in RO scale groups and were dose dependent. In conclusion, methanolic extract of ROS showed a protective effect against APH induced rats that may be attributed to potential anti-inflammatory and immunomodulatory effects.

Epidermal growth factor enhances androgen receptor‑mediated bladder cancer progression and invasion via potentiation of AR transactivation

Androgen receptor (AR) plays a critical role in bladder cancer (BCa) development. Our early studies found AR knock-out mice (with few androgens and deleted AR) failed to develop BCa, yet 50% of castrated mice (with few androgens and existing AR) still developed BCa in an N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) carcinogen-induced BCa mouse model, suggesting the existing AR in BCa of castrated mice may still play important roles in promoting BCa development at the castration level of androgens. The mechanism underlying this and/or which factors potentiate AR function at the castration level of androgen remains unclear. Epidermal growth factor (EGF), a key player in BCa progression, has been demonstrated to be able to potentiate AR transactivation in prostate cancer. In the present study, we found that EGF could increase BCa cell growth, migration and invasion in the presence of AR under the low amount of androgen and EGF was able to potentiate AR transactivation through EGFR by activating PI3K/AKT and MAPK pathway at castration androgen level. The increased suppression effects by EGFR inhibitor of PD168393 on AR function after addition of anti-androgen, Casodex, further suggested AR might play a key role in the effects of EGF on BCa progression and metastasis. Collectively, our results indicate that EGF may be able to potentiate AR transactivation that leads to enhancing BCa progression, which may help us to develop a better therapeutic approach to treat BCa via targeting both EGF and AR signaling.

Role of proprotein convertases in prostate cancer progression

Better understanding of the distinct and redundant functions of the proprotein convertase (PC) enzyme family within pathophysiological states has a great importance for potential therapeutic strategies. In this study, we investigated the functional redundancy of PCs in prostate cancer in the commonly used androgen-sensitive LNCaP and the androgen-independent DU145 human cell lines. Using a lentiviral-based shRNA delivery system, we examined in vitro and in vivo cell proliferation characteristics of knockdown cell lines for the endogenous PCs furin, PACE4, and PC7 in both cell lines. Of the three PCs, only PACE4 was essential to maintain a high-proliferative status, as determined in vitro using XTT proliferation assays and in vivo using tumor xenografts in nude mice. Furin knockdowns in both cell lines had no effects on cell proliferation or tumor xenograft growth. Paradoxically, PC7 knockdowns reduced in vitro cellular proliferation but had no effect in vivo. Because PCs act within secretion pathways, we showed that conditioned media derived from PACE4 knockdown cells had very poor cell growth-stimulating effects in vitro. Immunohistochemistry of PACE4 knockdown tumors revealed reduced Ki67 and higher p27(KIP) levels (proliferation and cell cycle arrest markers, respectively). Interestingly, we determined that the epidermal growth factor receptor signaling pathway was activated in PC7 knockdown tumors only, providing some explanations of the paradoxical effects of PC7 silencing in prostate cancer cell lines. We conclude that PACE4 has a distinct role in maintaining proliferation and tumor progression in prostate cancer and this positions PACE4 as a relevant therapeutic target for this disease.

Terazosin treatment induces caspase-3 expression in the rat ventral prostate

BACKGROUND

Quinazoline-based alpha1-adrenergic receptor antagonists may not act solely on smooth muscle contractility. We evaluated the in vivo effect of terazosin on the expression of caspase-3 in the rat ventral prostate.

METHODS

Fifteen Wistar rats were treated with terazosin (1.2 mg/kg body weight, given orally every second day) for 120 days. Another 15 control animals received the same amount of distilled water. The expression of caspase-3 was assessed immunohistochemically in formalin-fixed, paraffin-embedded tissue sections.

RESULTS

Terazosin treatment did not affect prostate weight and histomorphology. In controls caspase-3 was expressed weakly and sporadically. In contrast, strong and weak expression was evident in 67% and 33% of the terazosin-treated specimens, respectively.

CONCLUSIONS

These findings implicate the induction of caspase-3 expression by terazosin as a potential molecular mechanism of its apoptotic action on prostate cells.

The molecular biology of prostate cancer morbidity and mortality: Accelerated death from ejaculate poisoning?

The molecular biology of host-tumor interactions unique to human prostate cancer that cause patient morbidity are poorly understood despite the prevalence of this neoplasm. Little is known fundamentally about prostate-specific exocrine gene products secreted by metastatic prostate carcinoma cells at metastatic sites that cause diffuse bone pain, immunosuppression, anemia, cachexia, and other clinical signs of advanced prostate cancer. Growing evidence supports the presence of androgen-regulated exocrine gene products as independent mediators of prostate cancer morbidity. The experimental and clinical implications of a hypothesis that prostate-specific exocrine genes cause patient morbidity are discussed.

Identification of kinases regulating prostate cancer cell growth using an RNAi phenotypic screen

As prostate cancer progresses to castration-resistant disease, there is an increase in signal transduction activity. Most castration-resistant prostate tumors continue to express the androgen receptor (AR) as well as androgen-responsive genes, despite the near absence of circulating androgen in these patients. The AR is regulated not only by its cognate steroid hormone, but also by interactions with a constellation of co-regulatory and signaling molecules. Thus, the elevated signaling activity that occurs during progression to castration resistance can affect prostate cancer cell growth either through the AR or independent of the AR. In order to identify signaling pathways that regulate prostate cancer cell growth, we screened a panel of shRNAs targeting 673 human kinases against LNCaP prostate cancer cells grown in the presence and absence of hormone. The screen identified multiple shRNA clones against known and novel gene targets that regulate prostate cancer cell growth. Based on the magnitude of effect on growth, we selected six kinases for further study: MAP3K11, DGKD, ICK, CIT, GALK2, and PSKH1. Knockdown of these kinases decreased cell growth in both androgen-dependent and castration-resistant prostate cancer cells. However, these kinases had different effects on basal or androgen-induced transcriptional activity of AR target genes. MAP3K11 knockdown most consistently altered transcription of AR target genes, suggesting that MAP3K11 affected its growth inhibitory effect by modulating the AR transcriptional program. Consistent with MAP3K11 acting on the AR, knockdown of MAP3K11 inhibited AR Ser 650 phosphorylation, further supporting stress kinase regulation of AR phosphorylation. This study demonstrates the applicability of lentiviral-based shRNA for conducting phenotypic screens and identifies MAP3K11, DGKD, ICK, CIT, GALK2, and PSKH1 as regulators of prostate cancer cell growth. The thorough evaluation of these kinase targets will pave the way for developing more effective treatments for castration-resistant prostate cancer.

Mechanisms of prostate atrophy after LHRH antagonist cetrorelix injection: an experimental study in a rat model of benign prostatic hyperplasia

In the present study, we investigated the roles of TGF-β signaling pathway in a rat benign prostatic hyperplasia (BPH) model treated with cetrorelix. TGF-β1 and c-Myc expression were measured by qRT-PCR and Western blotting in the proximal and distal region of ventral prostatic lobes, respectively. We observed that treatment with cetrorelix led to a significant reduction of ventral prostate weight in a dose-dependent manner. In the proximal region, after cetrorelix treatment, the expression of TGF-β1 was dramatically increased (P<0.05), while the expression of c-Myc was significantly decreased (P<0.05). In comparison with the control group, the cetrorelix groups had more TUNEL-positive cells. Our findings strongly suggest that the TGF-β signaling pathway may be one of the major causes responsible for prostate volume reduction in BPH rats after cetrorelix treatment.

Prostate cancer cells and bone stromal cells mutually interact with each other through bone morphogenetic protein-mediated signals

Functional interactions between cancer cells and the bone microenvironment contribute to the development of bone metastasis. Although the bone metastasis of prostate cancer is characterized by increased ossification, the molecular mechanisms involved in this process are not fully understood. Here, the roles of bone morphogenetic proteins (BMPs) in the interactions between prostate cancer cells and bone stromal cells were investigated. In human prostate cancer LNCaP cells, BMP-4 induced the production of Sonic hedgehog (SHH) through a Smad-dependent pathway. In mouse stromal MC3T3-E1 cells, SHH up-regulated the expression of activin receptor IIB (ActR-IIB) and Smad1, which in turn enhanced BMP-responsive reporter activities in these cells. The combined stimulation with BMP-4 and SHH of MC3T3-E1 cells cooperatively induced the expression of osteoblastic markers, including alkaline phosphatase, bone sialoprotein, collagen type II α1, and osteocalcin. When MC3T3-E1 cells and LNCaP cells were co-cultured, the osteoblastic differentiation of MC3T3-E1 cells, which was induced by BMP-4, was accelerated by SHH from LNCaP cells. Furthermore, LNCaP cells and BMP-4 cooperatively induced the production of growth factors, including fibroblast growth factor (FGF)-2 and epidermal growth factor (EGF) in MC3T3-E1 cells, and these may promote the proliferation of LNCaP cells. Taken together, our findings suggest that BMPs provide favorable circumstances for the survival of prostate cancer cells and the differentiation of bone stromal cells in the bone microenvironment, possibly leading to the osteoblastic metastasis of prostate cancer.

Fraction of macroporous resin from Smilax china L. inhibits testosterone propionate-induced prostatic hyperplasia in castrated rats

The present study was conducted to evaluate the effect of a fraction of macroporous resin (FMR), a bioactive component of Smilax china L., on benign prostatic hyperplasia (BPH) in castrated rats induced by testosterone propionate. Rats were randomly divided into five groups: the negative control group (sham-operated), the model group, two FMR-treated groups (at doses of 300 mg/kg and 600 mg/kg of body weight), and the positive control group (treated with finasteride at the dose of 3 mg/kg). Drugs were administered once a day for three consecutive weeks by gastric gavage. Prostates were weighed, testosterone and dihydrotestosterone (DHT) levels in serum were determined, and histopathological examinations were carried out. FMR treatment inhibited prostatic hyperplasia, reducing the DHT level in serum and improving the prostate gland morphology compared with the model group. The overall results of this study suggest that FMR is effective at inhibiting experimentally induced prostate enlargement, and it presents a valuable resource for the treatment of human BPH.

Enhanced vascular permeability is hypothesized to promote inflammation-induced carcinogenesis and tumor development via extravasation of large molecular proteins into the tissue

We propose that the growth of solid tumors is dependent, in part, on the entry of large molecular blood-borne growth regulators into the tissue and is facilitated by the highly permeable nature of tumor blood vessels. There is abundant evidence that the tumor vasculature is hyperpermeable and tumor growth is dependent on mediators that increase vascular permeability (e.g., VEGF and mast cells). Therefore, the extravasation of plasma proteins into the interstitial space could be an important determinant of tumor growth. Angiogenesis promotes cancer by creating a network of blood vessels that supplies oxygen and nutriment. A highly permeable vasculature could complement this by facilitating the entry of plasma proteins into the tumor space, permitting them to exert effects on growth and survival pathways. Plasma proteins could act directly (on the cancer cells) or indirectly (via the stroma), and could conceivably stimulate cell proliferation, enhance cell survival, promote angiogenesis, and/or provide the cells with essential nutrients. Since increased vascular permeability is a hallmark of inflammation and since chronic inflammation is a forerunner to cancer, we also suggest that the prolonged influx of plasma proteins during chronic inflammation could contribute to the carcinogenic process. Perhaps over time and in sufficient quantity, the extruded plasma proteins and the attendant edema set up a feed-forward cycle that exacerbates the inflammation and potentiates the formation of mutagens and growth regulators. It is tempting to speculate that differences in tumor growth/metastasis and patient outcome are at least partly due to the degree of permeability of the tumor vasculature.

Antagonists of growth hormone-releasing hormone inhibit growth of androgen-independent prostate cancer through inactivation of ERK and Akt kinases

The management of castration-resistant prostate cancer (CRPC) presents a clinical challenge because of limitations in efficacy of current therapies. Novel therapeutic strategies for the treatment of CRPC are needed. Antagonists of hypothalamic growth hormone-releasing hormone (GHRH) inhibit growth of various malignancies, including androgen-dependent and independent prostate cancer, by suppressing diverse tumoral growth factors, especially GHRH itself, which acts as a potent autocrine/paracrine growth factor in many tumors. We evaluated the effects of the GHRH antagonist, JMR-132, on PC-3 human androgen-independent prostate cancer cells in vitro and in vivo. JMR-132 suppressed the proliferation of PC-3 cells in vitro in a dose-dependent manner and significantly inhibited growth of PC-3 tumors by 61% (P < 0.05). The expression of GHRH, GHRH receptors, and their main splice variant, SV1, in PC-3 cells and tumor xenografts was demonstrated by RT-PCR and Western blot. The content of GHRH protein in PC-3 xenografts was lowered markedly, by 66.3% (P < 0.01), after treatment with JMR-132. GHRH induced a significant increase in levels of ERK, but JMR-132 abolished this outcome. Our findings indicate that inhibition of PC-3 prostate cancer by JMR-132 involves inactivation of Akt and ERK. The inhibitory effect produced by GHRH antagonist can result in part from inactivation of the PI3K/Akt/mammalian target of rapamycin and Raf/MEK/ERK pathways and from the reduction in GHRH produced by cancer cells. Our findings support the role of GHRH as an autocrine growth factor in prostate cancer and suggest that antagonists of GHRH should be considered for further development as therapy for CRPC.

Anti-inflammatory and antiproliferative activities of date palm pollen (Phoenix dactylifera) on experimentally-induced atypical prostatic hyperplasia in rats

BACKGROUND

Atypical prostatic hyperplasia (APH) is a pseudoneoplastic lesion that can mimic prostate adenocarcinoma because of its cytologic and architectural features. Suspension of date palm pollen (DPP) is an herbal mixture that is widely used in folk medicine for male infertility. The aim of the present study was to evaluate the effect of DPP suspension and extract on APH-induced rats.

METHODS

APH was induced in adult castrated Wistar rats by both s.c. injection of testosterone (0.5 mg/rat/day) and smearing citral on shaved skin once every 3 days for 30 days. Saw palmetto (100mg/kg), DPP suspension (250, 500 and 1000 mg/kg), and lyophilized DPP extract (150,300 and 600 mg/kg) were given orally daily for 30 days. All medications were started 7 days after castration and along with testosterone and citral.

RESULTS

The histopathological feature in APH-induced prostate rats showed evidence of hyperplasia and inflammation. Immunohistochemical examination revealed that the expressions of IL-6, IL-8, TNF-α, IGF-1 and clusterin were increased, while the expression of TGF-β1 was decreased that correlates with presence of inflammation. Moreover, histopathological examination revealed increased cellular proliferation and reduced apoptosis in ventral prostate. Both saw palmetto and DPP treatment has ameliorated these histopathological and immunohistochemical changes in APH-induced rats. These improvements were not associated with reduction in the prostatic weight that may be attributed to the persistence of edema.

CONCLUSION

DPP may have a potential protective effect in APH-induced Wistar rats through modulation of cytokine expression and/or upregulation of their autocrine/paracrine receptors.

Suppressed prostate epithelial development with impaired branching morphogenesis in mice lacking stromal fibromuscular androgen receptor

Using the cre-loxP system, we generated a new mouse model [double stromal androgen receptor knockout (dARKO)] with selectively deleted androgen receptor (AR) in both stromal fibroblasts and smooth muscle cells, and found the size of the anterior prostate (AP) lobes was significantly reduced as compared with those from wild-type littermate controls. The reduction in prostate size of the dARKO mouse was accompanied by impaired branching morphogenesis and partial loss of the infolding glandular structure. Further dissection found decreased proliferation and increased apoptosis of the prostate epithelium in the dARKO mouse AP. These phenotype changes were further confirmed with newly established immortalized prostate stromal cells (PrSC) from wild-type and dARKO mice. Mechanistically, IGF-1, placental growth factor, and secreted phosphoprotein-1 controlled by stromal AR were differentially expressed in PrSC-wt and PrSC-ARKO. Moreover, the conditioned media (CM) from PrSC-wt promoted prostate epithelium growth significantly as compared with CM from PrSC-dARKO. Finally, adding IGF-1/placental growth factor recombinant proteins into PrSC-dARKO CM was able to partially rescue epithelium growth. Together, our data concluded that stromal fibromuscular AR could modulate epithelium growth and maintain cellular homeostasis through identified growth factors.

Attenuation of androgenic regulation by brefeldin A in androgen-responsive prostate cancer cells

OBJECTIVES

To investigate the effects of an antibiotic brefeldin A (BFA) on androgen-regulated cellular events in androgen-responsive prostate cancer cells, focusing on PSA (prostate-specific antigen) status, cell growth, and bioactivity of androgen receptor (AR).

MATERIALS AND METHODS

Androgen-responsive human prostate cancer LNCaP cells were employed and 5α-dihydrotestosterone (DHT) was used as an androgenic mediator to induce androgen-modulated cellular events. Effects of BFA on synthesis and secretion of PSA, cell growth, and AR activity were assessed using Tandem PSA assay, trypan blue exclusion method, and AR binding assay, respectively.

RESULTS

BFA (30 ng/ml) dramatically (90%) blocked secretion of PSA and also reduced cell growth by >75% under non-androgen-regulated condition. Under androgen-stimulated condition using DHT (1 nM), both the cellular and secreted PSA levels as well as cell growth was significantly elevated or stimulated by DHT (compared with controls); however, BFA was capable of completely inhibiting such DHT-stimulated cellular events. In addition, AR binding assay revealed that AR activity has been drastically (~90%) diminished by BFA, likely resulting in interruption of DHT-mediated events.

CONCLUSIONS

BFA is capable of attenuating androgenic regulation in LNCaP cells such as androgen-stimulated PSA synthesis/secretion and cell growth. This BFA-blocked androgen action appears to be primarily attributed to severe inactivation of AR with BFA because AR is a crucial factor for relaying androgenic messages (to DNA). Therefore, BFA could be considered a promising agent for a more effective treatment of hormone-dependent prostate cancer.

Benign prostatic hyperplasia: An overview of existing treatment

Benign prostatic hyperplasia (BPH) is the most common condition in aging men, associated with lower urinary tract symptoms (LUTS). A better understanding of the prostate physiology, function, and pathogenesis has led to the development of promising agents, useful in the management of LUTS in men. The specific approach used to treat BPH depends upon number of factors like age, prostrate size, weight, prostate-specific antigen level, and severity of the symptoms. 5α-reductase inhibitors decrease the production of dihydrotestosterone within the prostate, which results in decreased prostate volume, increased peak urinary flow rate, improvement of symptoms, decreased risk of acute urinary retention, and need for surgical intervention. α(1)-adrenergic receptor (α(1)-AR) antagonists decrease LUTS and increase urinary flow rates in men with symptomatic BPH, but do not reduce the long-term risk of urinary retention or need for surgical intervention. Clinical efficacy of either 5α-reductase inhibitor or α(1)-AR antagonist has been further improved by using combination therapy; however, long-term outcomes are still awaited. Many more potential new therapies are under development that may improve the treatment of BPH. This article gives a brief account of rationale and efficacy of different treatment options presently available in the management of BPH.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Angiogenin as a molecular target for the treatment of prostate cancer

Angiogenin (ANG), a 14 kDa angiogenic ribonuclease, is upregulated in human prostate cancers, especially in hormone refractory diseases, and is the highest upregulated gene in Akt-driven prostate intraepithelial neoplasia (PIN) in mice. ANG has been shown to undergo nuclear translocation in both prostate cancer cells and cancer-associated endothelial cells where it binds to the promoter region of ribosomal DNA (rDNA) and stimulates ribosomal RNA (rRNA) transcription. ANG thus plays an essential role in prostate cancer progression by stimulating both cancer cell proliferation and tumor angiogenesis. A variety of ANG antagonists, including its antisense oligonucleotide, siRNA, soluble binding proteins, monoclonal antibody, enzymatic inhibitors, and nuclear translocation blockers, have all been shown to inhibit prostate cancer in various animal models. Accumulating evidence indicates that ANG is a molecular target for prostate cancer drug development.

Effect of dexamethasone and testosterone treatment on the regulation of insulin-degrading enzyme and cellular changes in ventral rat prostate after castration

Insulin-degrading enzyme (IDE) has been shown to enhance the binding of androgen and glucocorticoid receptors to DNA in the nuclear compartment. Glucocorticoids cause hyperglycaemia, peripheral resistance to insulin and compensatory hyperinsulinaemia. The aim of the present study was to investigate the effect of dexamethasone (D), testosterone (T) and dexamethasone plus testosterone (D + T) on the regulation of IDE and on the remodelling of rat ventral prostate after castration (C). Castration led to a marked reduction in prostate weight (PW). Body weight was significantly decreased in the castrated animals treated with dexamethasone, and the relative PW was 2.6-fold (±0.2) higher in the D group, 2.8-fold (±0.3) higher in the T group and 6.6-fold (±0.6) higher in the D + T group in comparison with the castrated rats. Ultrastructural alterations in the ventral prostate in response to androgen deprivation were restored after testosterone and dexamethasone plus testosterone treatments and partially restored with dexamethasone alone. The nuclear IDE protein level indicated a 4.3-fold (±0.4) increase in castrated rats treated with D + T when compared with castration alone. Whole-cell IDE protein levels increased approximately 1.5-fold (±0.1), 1.5-fold (±0.1) and 2.9-fold (±0.2) in the D, T and D + T groups, respectively, when compared with castration alone. In conclusion, the present study reports that dexamethasone-induced hyperinsulinaemic condition plus exogenous testosterone treatment leads to synergistic effects of insulin and testosterone in the prostatic growth and in the amount of IDE in the nucleus and whole epithelial cell.

Receptors for luteinizing hormone-releasing hormone (LHRH) in benign prostatic hyperplasia (BPH) as potential molecular targets for therapy with LHRH antagonist cetrorelix

BACKGROUND

The majority of men will develop symptoms of benign prostatic hyperplasia (BPH) after 70 years of age. Various studies indicate that antagonists of LHRH, such as cetrorelix, exert direct inhibitory effects on BPH mediated by specific LHRH receptors. Our aim was to investigate the mRNA for LHRH and LHRH receptors and the expression of LHRH receptors in specimens of human BPH.

METHODS

The expression of mRNA for LHRH (n=35) and LHRH receptors (n=55) was investigated by RT-PCR in surgical specimens of BPH, using specific primers. The characteristics of binding sites for LHRH on 20 samples were determined by ligand competition assays. The LHRH receptor expression was also examined in 64 BPH specimens by immunohistochemistry.

RESULTS

PCR products for LHRH were found in 18 of 35 (51%) BPH tissues and mRNA for LHRH receptors was detected in 39 of 55 (71%) BPH specimens. Eighteen of 20 (90%) samples showed a single class of high affinity binding sites for [D-Trp(6) ]LHRH with a mean K(d) of 4.04 nM and a mean B(max) of 527.6 fmol/mg membrane protein. LHRH antagonist cetrorelix showed high affinity binding to LHRH receptors in BPH. Positive immunohistochemical reaction for LHRH receptors was present in 42 of 64 (67%) BPH specimens.

CONCLUSION

A high incidence of LHRH receptors in BPH supports the use of LHRH antagonists such as cetrorelix, for treatment of patients with lower urinary tract symptoms from BPH.

Natural antibodies against nerve growth factor inhibit in vitro prostate cancer cell metastasis

Prostate cancer is a major cause of death in older men, and bone metastasis is the primary cause of morbidity and mortality in prostate cancer. Prostate is an abundant source of nerve growth factor (NGF) that is secreted by malignant epithelial cells and utilized as an important autocrine factor for growth and metastasis. We previously showed that intravenous gammaglobulin (IVIg) contains natural antibodies against NGF, which inhibit growth and differentiation of the NGF-dependent cell line PC-12. In the present study, we examined the effects of these natural antibodies on in vitro migration or metastasis of two prostate cancer cell lines namely DU-145 and PC-3. Cancer cell migration was assessed using these cell lines in the upper chambers of Matrigel invasion chambers. The effects of IVIg and affinity-purified anti-NGF antibodies on cell migration through membrane into the lower chamber were assessed in dose/response experiments by a colorimetric method. Affinity-purified natural IgG anti-NGF antibody inhibited DU-145 migration by 38% (p = 0.01) and PC-3 migration by 25% (p = 0.02); whereas, a monoclonal anti-NGF antibody inhibited DU-145 migration by 40% (p = 0.01) and PC-3 migration by 37% (p = 0.02), at the same concentration. When IVIg was depleted of NGF-specific IgG by affinity chromatography, there was no significant inhibition of migration of the DU-145 and PC-3 cells at a concentration of 1 mg/well. Removal of the NGF-specific antibody from the IVIg was also demonstrated by a lack of effect on PC-12 cell differentiation. Therefore, IVIg is able to inhibit the migration of prostate cancer cell lines, through Matrigel chambers in vitro, only when the natural NGF-specific antibodies actively are present in IVIg.

Dose-ranging study of the luteinizing hormone-releasing hormone receptor antagonist cetrorelix pamoate in the treatment of patients with symptomatic benign prostatic hyperplasia

OBJECTIVE

To compare the efficacy of 4 dosage regimens of cetrorelix pamoate, a sustained release formulation that allows for more convenient dosing, in patients with symptomatic benign prostatic hyperplasia (BPH). Repeated dosing with cetrorelix acetate was shown to be active in the treatment of BPH symptoms.

METHODS

Double-blind, randomized, multicenter study was undertaken among patients with International Prostate Symptom Score (IPSS) ≥ 13. After a single-blind placebo run-in phase of 4 weeks, treatment was administered at 2-week intervals as follows: 30 + 30 mg, 30 + 30 + 30 mg, 60 + 30, 60 + 60 mg cetrorelix pamoate, or matching placebo. Patients were followed-up for 28 weeks after randomization.

RESULTS

A statistically significant overall difference was found with respect to the primary variable, the IPSS (P ≤ .001). Optimal results, a 4-point improvement in IPSS in excess of the changes observed in the placebo group, were achieved with a starting dose of 60 mg cetrorelix pamoate followed by a dose of 30 mg 2 weeks later. In all dosage groups, the symptomatic improvement was paralleled by an increase in uroflow. There was a marked dissociation between only moderate and transient testosterone suppression and the persisting effects on BPH signs and symptoms. Tolerability was good at all cetrorelix dosages.

CONCLUSIONS

Intramuscular injections of 60 and 30 mg of cetrorelix pamoate within 2 weeks provide rapid symptomatic improvements of BPH that are sustained for the following 6 months.

Effect of transforming growth factor α overexpression on urogenital organ development in mouse

Transforming growth factor-α (TGFα) promotes cell proliferation by binding to the epidermal growth factor receptor (EGFR). TGFα and EGFR overexpression have been reported in various human cancers. However, whether TGFα induces cancer by itself is unknown in urogenital organs. To investigate whether TGFα overexpression induces carcinogenesis in urogenital organs, we analyzed the phenotypes of urogenital organs in male TGFα transgenic (TG) mice of the CD1 strain. Urogenital organs including the kidney, bladder, prostate, seminal vesicles, testes, and epididymis were isolated from 4- to 48-week-old TGFα TG and wild-type (WT) CD1 mice. Prostates were separated into anterior prostate (AP), dorsolateral prostate (DLP), and ventral prostate (VP). Neither tumor formation nor epithelial hyperplasia was observed in the TGFα TG mouse urogenital organs that we have investigated. Histopathologically, in prostate, we found an increased number of p63-positive basal epithelial cells in the TGFα TG mice AP and DLP. There was no morphological change in the stromal component, such as hypercellular stroma or fibrosis. However, bladder weight was greater in TGFα TG mice than that in WT mice, and distended bladders were observed macroscopically in 19 of 20 TGFα TG mice over 20 weeks of age. Ki67 labeling index was increased significantly in the TGFα TG mouse urethral epithelium, whereas neither epithelial hyperplasia nor hypertrophy was observed. In conclusion, our results suggest that TGFα overexpression in mouse urogenital organs alone may not be responsible for tumor formation and epithelial hyperplasia, but is involved in bladder outlet obstruction.

Progression to metastatic stage in a cellular model of prostate cancer is associated with methylation of the androgen receptor gene and transcriptional suppression of the insulin-like growth factor-I receptor gene

The progression of prostate cancer from an organ-confined, androgen-sensitive disease to a metastatic one is associated with dysregulation of androgen receptor (AR)-regulated target genes and with a decrease in insulin-like growth factor-I receptor (IGF1R) expression. DNA methylation of CpG islands is an epigenetic mechanism associated with gene silencing. Recent studies have demonstrated that methylation occurs early in prostate carcinogenesis and, furthermore, may contribute to androgen independence. The methylation status of the AR and IGF1R genes was evaluated in a series of prostate cancer cell lines corresponding to early (benign) and advanced (metastatic) stages of the disease. Results of 5-Aza-2'-deoxycytidine (5-Aza) experiments, methylation-specific PCR, and sodium bisulfite-direct DNA sequencing revealed that the AR promoter is hypermethylated in metastatic M12, but not in benign P69, cells. On the other hand, no methylation was seen in the IGF1R promoter at any stage of the disease. We show, however, that 5-Aza treatment, which caused demethylation of the AR promoter, led to a significant increase in IGF1R mRNA levels, whereas addition of the AR inhibitor flutamide decreased the IGF1R mRNA levels to basal values measured prior to the 5-Aza treatment. Given that the IGF1R gene has been identified as a downstream target for AR action, our data is consistent with a model in which the AR gene undergoes methylation during progression of the disease, leading to dysregulation of AR targets, including the IGF1R gene, at advanced metastatic stages.