Differential Actions of Estrogen Receptor α and β via Nongenomic Signaling in Human Prostate Stem and Progenitor Cells

Human prostate stem and progenitor cells express estrogen receptor (ER)α and ERβ and exhibit proliferative responses to estrogens. In this study, membrane-initiated estrogen signaling was interrogated in human prostate stem/progenitor cells enriched from primary epithelial cultures and stem-like cell lines from benign and cancerous prostates. Subcellular fractionation and proximity ligation assays localized ERα and ERβ to the cell membrane with caveolin-1 interactions. Exposure to 17β-estradiol (E2) for 15 to 60 minutes led to sequential phosphorylation of signaling molecules in MAPK and AKT pathways, IGF1 receptor, epidermal growth factor receptor, and ERα, thus documenting an intact membrane signalosome that activates diverse downstream cascades. Treatment with an E2-dendrimer conjugate or ICI 182,870 validated E2-mediated actions through membrane ERs. Overexpression and knockdown of ERα or ERβ in stem/progenitor cells identified pathway selectivity; ERα preferentially activated AKT, whereas ERβ selectively activated MAPK cascades. Furthermore, prostate cancer stem-like cells expressed only ERβ, and brief E2 exposure activated MAPK but not AKT cascades. A gene subset selectively regulated by nongenomic E2 signaling was identified in normal prostate progenitor cells that includes BGN, FOSB, FOXQ1, and MAF. Membrane-initiated E2 signaling rapidly modified histone methyltransferases, with MLL1 cleavage observed downstream of phosphorylated AKT and EZH2 phosphorylation downstream of MAPK signaling, which may jointly modify histones to permit rapid gene transcription. Taken together, the present findings document ERα and ERβ membrane-initiated signaling in normal and cancerous human prostate stem/progenitor cells with differential engagement of downstream effectors. These signaling pathways influence normal prostate stem/progenitor cell homeostasis and provide novel therapeutic sites to target the elusive prostate cancer stem cell population.

Impairment of microvascular angiogenesis is associated with delay in prostatic development in rat offspring of maternal protein malnutrition

Experimental data demonstrated the negative impact of maternal protein malnutrition (MPM) on rat prostate development, but the mechanism behind the impairment of prostate growth has not been well understood. Male Sprague Dawley rats, borned to dams fed a normal protein diet (CTR group, 17% protein diet), were compared with those borned from dams fed a low protein diet (6% protein diet) during gestation (GLP group) or gestation and lactation (GLLP). The ventral prostate lobes (VP) were removed at post-natal day (PND) 10 and 21, and analyzed via different methods. The main findings were low birth weight, a reduction in ano-genital distance (AGD, a testosterone-dependent parameter), and an impairment of prostate development. A delay in prostate morphogenesis was associated with a reduced testosterone levels and angiogenic process through downregulation of aquaporin-1 (AQP-1), insulin/IGF-1 axis and VEGF signaling pathway. Depletion of the microvascular network, which occurs in parallel to the impairment of proliferation and differentiation of the epithelial cells, affects the bidirectional flux between blood vessels impacting prostatic development. In conclusion, our data support the hypothesis that a reduction in microvascular angiogenesis, especially in the subepithelial compartment, is associated to the impairment of prostate morphogenesis in the offspring of MPM dams.

Streptozotocin-Induced Maternal Hyperglycemia Increases the Expression of Antioxidant Enzymes and Mast Cell Number in Offspring Rat Ventral Prostate

Gestational diabetes mellitus (GDM) has increased in recent years. Although the cellular and molecular mechanisms involved in GDM-increased risk factors to offspring remained poorly understood, some studies suggested an association between an increase in oxidative stress induced by maternal hyperglycemia and complications for both mothers and newborns. Here, we investigated the impact of maternal hyperglycemia followed by maternal insulin replacement during lactation on the expression of antioxidant enzymes and mast cell number in offspring ventral prostate (VP) at puberty. Pregnant rats were divided into three groups: control (CT); streptozotocin-induced maternal hyperglycemia (MH); and MH plus maternal insulin replacement during lactation (MHI). Male offspring were euthanized at postnatal day (PND) 60 and the VP was removed and processed for histology and Western blotting analyses. Maternal hyperglycemia delayed prostate maturation, and increased mast cell number catalase (CAT), superoxide dismutase (SOD), glutatione-s-transferase (GST-pi), and cyclooxygenase-2 (Cox-2) expression in the offspring of hyperglycemic dams. Maternal insulin replacement restored VP structure, mast cell number and antioxidant protein expression, except for Cox-2, which remained higher in the MHI group. Thus, an increase in oxidative stress induced by intrauterine hyperglycemia impacts prostate development and maturation, which persists until puberty. The overall improvement of maternal metabolism after insulin administration contributes to the restoration of prostate antioxidant enzymes and secretory function. Taken together, our results highlighted that imbalanced physiological maternal-fetal interaction contributes to the impairment of reproductive performance of the offspring from diabetic mothers. Anat Rec, 300:291-299, 2017. © 2016 Wiley Periodicals, Inc.

Effects of intra-articular injection of mesenchymal stem cells associated with platelet-rich plasma in a rabbit model of osteoarthritis

The current study aims to evaluate the macroscopic and histological effects of autologous mesenchymal stem cells (MSC) and platelet-rich plasma on knee articular cartilage regeneration in an experimental model of osteoarthritis. Twenty-four rabbits were randomly divided into four groups: control group, platelet-rich plasma group, autologous MSC undifferentiated group, and autologous MSC differentiated into chondrocyte group. Collagenase solution was used to induce osteoarthritis, and treatments were applied to each group at 6 weeks following osteoarthritis induction. After 60 days of therapy, the animals were euthanized and the articular surfaces were subjected to macroscopic and histological evaluations. The adipogenic, chondrogenic, and osteogenic differentiation potentials of MSCs were evaluated. Macroscopic and histological examinations revealed improved tissue repair in the MSC-treated groups. However, no difference was found between MSC-differentiated and undifferentiated chondrocytes. We found that MSCs derived from adipose tissue and platelet-rich plasma were associated with beneficial effects in articular cartilage regeneration during experimental osteoarthritis.

ID: 22: DIFFERENTIAL ACTIONS OF ESTROGEN RECEPTOR α AND β VIA NON-GENOMIC SIGNALING IN HUMAN PROSTATE STEM-PROGENITOR CELLS

Genomic signaling via estrogen receptors (ER) has been widely studied and implicated as the main ER signaling pathway in prostate development and carcinogenesis. Non-genomic ER signaling has also been reported in prostate epithelium although down-stream cascades have not been clarified. Our lab has recently identified ERs in human prostate epithelial stem/progenitor cells and shown that that 17β-estradiol (E2) can stimulate stem cell symmetric self-renewal and progenitor cell proliferation. In this study we interrogate non-genomic membrane initiated ER signaling in this prostate stem/progenitor cell population. Human prostate stem-progenitor cells were enriched from primary prostate epithelial cell cultures (PrEC) of young, disease-free donors using a 3D prostasphere (PS) model as previously described. Cells were labeled using ERα or ERβ antibodies along with prostate stem cell markers CD49f and TROP2 followed by triple channel FACS to quantify ERα+/ERβ+ cell numbers. To explore ERα, the benign human prostate stem cell line WPE with extremely low levels of ERα and ERβ, was stably transfected with a lentiviral-ERα expression vector. The human prostate cancer stem-like cell line HuSLC (ERβ++, ERα−) was utilized to interrogate ERb actions. Cells were exposed to 10 nM estradiol (E2) over a 15 to 60 minute time course +/− ICI 182,870 (ICI), an ERα/β antagonist. FACS analysis of day 7 PS cells labeled for ERα or ERβ revealed 66% of day 7 PS cells as ERα+ and 40% as ERβ+. Among ERα or ERβ positive PS cells, 4% were Trop2+/CD49fhigh (stem-like cells) and 10–12% were Trop2+/CD49fmedium (early stage progenitor cells). PS exposed to 10 nM E2 showed sequential phosphorylation of Src, Erk1/2, p38, Akt and NFκB (p65) over 60 minutes. Phosphorylation of up-and downstream targets (EGFR, Jnk, GSK 3α/β, p70 S6 kinase, PRAS40, MSK1/2) was also seen using a phospho-kinase array. Furthermore, phosphorylation of ERα at S167 was noted over 60 min of E2 exposure enabling enhancement of genomic ERα transactivational activity in a feed-forward manner. ICI attenuated Akt and Erk1/2 phosphorylation, confirming membrane bound ERs are involved in downstream signaling. E2 treatment of HuSLCs showed phosphorylation of Erk1/2 but not Akt, indicating that ERβ signals exclusively through the MAPK pathway in these cells. Conversely, E2 treatment of WPE-stem cells overexpressing ERα resulted in robust phosphorylation of Akt but lower levels of Erk1/2 phosphorylation suggesting that Akt activation may be more reliant on ERα signaling. To identify pathway specific roles, specific inhibitors were added to PS cultures. PS treated with LY294002 (Akt inhibitor) for 7 days attenuated the E2-mediated increase in PS number and size. Inhibition of the NFκB downstream of the Akt pathway by IKK VII (IKK inhibitor) blocked p65 phosphorylation, abrogated the E2-induced increase in stem cell symmetric self-renewal and blunted E2 stimulation of progenitor cell proliferation. Analysis of PS cyclin mRNA levels revealed a G1 arrest of progenitor cells upon IKK inhibition suggesting an essential role of NFκB in progenitor cell amplification. MAPK pathway inhibition with U0126(Erk1/2 inhibitor) resulted in an attenuation of the E2-mediated increase in PS number and size and an increase stem cell symmetric self-renewal suggesting that MAPK pathway activation promotes commitment to stem and progenitor cell expansion. Taken together, the present findings reveal that human prostate stem-progenitor cells express both ERα and ERβ which differentially activate different signaling cascades originating at the membrane. These signaling events may lead to unique downstream actions that influence prostate stem-progenitor cell proliferation as well as lineage commitment decisions.

Abstract 827: Analysis of p63 protein expression in rat ventral prostate submitted to intrauterine undernutrition associated to hormonal exposure in adult life

Basal cells expressing p63 contain multipotent stem cells that can efficiently differentiate during postnatal prostate morphogenesis, adult prostate epithelial homeostasis and carcinogenesis. Our project aim is to investigate p63 expression by focusing on the rates of basal epithelial cell proliferation/differentiation in the ventral prostate after intrauterine undernutrition (IUN) associated with or without hormonal exposure in adult life. Briefly, 20 Sprague Dawley dams were distributed equally into two groups during gestation: control diet (NP; fed a normal diet containing 17% protein) and restricted protein diet (RP, fed a diet containing 6% protein). After birth, all animals were maintained on the control diet. Experiment 1: To analyze p63 expression during prostate development, NP and RP animals were euthanized at postnatal day (PND) 3, 10, 21 and 35. The ventral prostate (VP) was dissected, weighed and processed for IHC (Ki67, p63 and AR) and Western blot (WB) analysis (PCNA, p63 and AR). Experiment 2: To analyze p63 expression in adults after hormonal exposure, 14 week-old NP and RP animals were subjected to 17-beta estradiol+testosterone administration (subcutaneous implant) for 16 weeks. The animals were killed at 35 weeks old and the VP was excised, weighed and processed for IHC and WB analysis. RP treated animals showed lower body weight compared to NP control treated animals. Reductions of testosterone plasma levels as well as the absolute and relative values of VP weights from the RP animals compared to the NP animals were observed. Normal glandular architecture was observed in both groups at PND 3, 10, 21 and 35. There was a reduction of AR expression in VP from RP animals at all ages analyzed. However, the proliferation rate and p63+ cells were higher in the RP group indicating that the low androgenic stimulation induced by IUN promoted a delay in VP development. As a consequence, the proliferation/differentiation cell dynamic was impaired, leading to an increase in basal cell number and damaging their differentiation into secretory luminal cells. We observed in hormone exposed adults that prostatitis aggressiveness and prostatic intraepithelial neoplasia (PIN) incidence were higher in the RP compared to NP animals. These results were followed by a decrease in apoptosis index and increases in proliferation rate and p63+ cells. It is clear that IUN alters adult prostate response to androgen/estrogen exposure and interferes in adult prostate susceptibility to diseases. In conclusion, IUN-induced fetal programming impairs ventral prostate growth, maturation and homeostasis highlighting the importance of adequate nutritional status during embryonic/fetal development.

Note: This abstract was not presented at the meeting.

Citation Format: Jaqueline C. Rinaldi, Caroline N. Barquilha, Sergio AA Santos, Ana C. Camargo, Ketlin T. Colombelli, Sergio L. Felisbin, Luis A. Justulin. Analysis of p63 protein expression in rat ventral prostate submitted to intrauterine undernutrition associated to hormonal exposure in adult life. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 827. doi:10.1158/1538-7445.AM2015-827

Cadmium exposure inhibits MMP2 and MMP9 activities in the prostate and testis

Matrix metalloproteinases (MMPs) are zinc (Zn(2+)) and calcium (Ca(2+)) dependant endopeptidases, capable of degradation of numerous components of the extracellular matrix. Cadmium (Cd(2+)) is a well known environmental contaminant which could impair the activity of MMPs. In this sense, this study was conducted to evaluate if Cd(2+) intake inhibits these endopeptidases activities at the rat prostate and testicles and if it directly inhibits the activity of MMP2 and MMP9 at gelatinolytic assays when present in the incubation buffer. To investigate this hypothesis, Wistar rats (5 weeks old), were given tap water (untreated, n = 9), or 15 ppm CdCl2 diluted in drinking water, during 10 weeks (n = 9) and 20 weeks (n = 9). The animals were euthanized and their ventral prostate, dorsal prostate, and testicles were removed. These tissue samples were processed for protein extraction and subjected to gelatin zymography evaluation. Additionally, we performed an experiment of gelatin zymography in which 5 μM or 2 mM cadmium chloride (CdCl2) was directly dissolved at the incubation buffer, using the prostatic tissue samples from untreated animals that exhibited the highest MMP2 and MMP9 activities in the previous experiment. We have found that CdCl2 intake in the drinking water led to the inhibition of 35% and 30% of MMP2 and MMP9 (p < 0.05) at the ventral prostate and testis, respectively, in Cd(2+) treated animals when compared to controls. Moreover, the activities of the referred enzymes were 80% and 100% inhibited by 5 μM and 2 mM of CdCl2, respectively, even in the presence of 10 mM of CaCl2 within the incubation buffer solution. These important findings demonstrate that environmental cadmium contamination may deregulate the natural balance in the extracellular matrix turnover, through MMPs downregulation, which could contribute to the toxic effects observed in prostatic and testicular tissue after its exposure.

Impact of gestational diabetes and lactational insulin replacement on structure and secretory function of offspring rat ventral prostate

Clinical and experimental studies have shown that exposure to adverse conditions during the critical stages of embryonic, fetal or neonatal development lead to a significantly increased risk of later disease. Diabetes during pregnancy has been linked to increased risk of obesity and diabetes in offspring. Here, we investigated whether mild gestational diabetes mellitus (GDM) followed or not by maternal insulin replacement affects the ventral prostate (VP) structure and function in male offspring at puberty and adulthood. Pregnant rats were divided into the following 3 groups: control (CT); streptozotocin (STZ)-induced diabetes (D); and D plus insulin replacement during lactation (GDI). The male offspring from different groups were euthanized at postnatal day (PND) 60 and 120. Biometrical parameters, hormonal levels and prostates were evaluated. Mild-GDM promoted reduction in the glandular parenchyma and increased collagen deposition. Insulin replacement during lactation restored the VP morphology. Most importantly, mild-GDM decreased the androgen-induced secretory function as determined by prostatein expression, and insulin replacement reversed this effect. Our results demonstrated that mild GDM impairs VP parenchyma maturation, which is associated with an increase in the fibromuscular stroma compartment. Functionally, the reduction in the VP parenchyma decreases the glandular secretory activity as demonstrated by low expression of prostatein, a potent immunosuppressor factor that protects sperm from immunologic damage into the feminine reproductive tract. This change could lead to impairment of reproductive function in male offspring from diabetic mothers. Maternal insulin replacement during the weaning period apparently restores the prostate function in male offspring.

Gestational protein restriction delays prostate morphogenesis in male rats

Maternal malnutrition due to a low-protein diet is associated with functional disorders in adulthood, which may be related to embryonic development failures. The effects of gestational protein restriction on prostate morphogenesis in male offspring were investigated. Pregnant rat dams were divided into normoprotein (NP; fed a normal diet containing 17% protein) and hypoprotein (LP; fed a diet containing 6% protein) groups. On the day of birth (PND1), anogenital distance and bodyweight were measured in male pups. Seven males per experimental group (one male per litter) were killed, and the pelvic urethra was evaluated. LP offspring showed a significant reduction in bodyweight and anogenital distance on PND1. On three-dimensional reconstruction of the prostate, the number of prostatic buds was lower in LP than in NP males. Mesenchymal cells surrounding the buds were androgen-receptor positive, and the quantity and intensity of nucleus immunoreactivity was decreased in LP. The proliferation index was lower in LP than in NP prostatic buds. Immunoreactivity for α-actin in mesenchymal cells and that for epidermal growth factor receptor in epithelial cells was higher in NP than in LP. Our findings demonstrate that maternal protein restriction delays prostatic morphogenesis, probably because of considerable disruption in the epithelium–mesenchyme interaction.

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

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