Role of estrogens in development of prostate cancer

The Pros and Cons of Estrogens in Prostate Cancer: An Update with a Focus on Phytoestrogens

The role of estrogens in prostate cancer (PCa) is shrouded in mystery, with its actions going from angelic to devilish. The findings by Huggins and Hodges establishing PCa as a hormone-sensitive cancer have provided the basis for using estrogens in therapy. However, despite the clinical efficacy in suppressing tumor growth and the panoply of experimental evidence describing its anticarcinogenic effects, estrogens were abolished from PCa treatment because of the adverse secondary effects. Notwithstanding, research work over the years has continued investigating the effects of estrogens, reporting their pros and cons in prostate carcinogenesis. In contrast with the beneficial therapeutic effects, many reports have implicated estrogens in the disruption of prostate cell fate and tissue homeostasis. On the other hand, epidemiological data demonstrating the lower incidence of PCa in Eastern countries associated with a higher consumption of phytoestrogens support the beneficial role of estrogens in counteracting cancer development. Many studies have investigated the effects of phytoestrogens and the underlying mechanisms of action, which may contribute to developing safe estrogen-based anti-PCa therapies. This review compiles the existing data on the anti- and protumorigenic actions of estrogens and summarizes the anticancer effects of several phytoestrogens, highlighting their promising features in PCa treatment.

New liquid chromatography tandem mass spectrometry reference data for estradiol show mini-puberty in both sexes and typical pre-pubertal and pubertal patterns

CONTEXT

Reliable estradiol (E2) reference intervals (RIs) are crucial in pediatric endocrinology.

OBJECTIVES

This study aims to develop a sensitive ultra-performance liquid chromatographic tandem mass spectrometry (UPLC-MS/MS) method for E2 in serum, to establish graphically represented RI percentiles and annual RIs for both sexes, and to perform a systematic literature comparison.

METHODS

First, a UPLC-MS/MS method for E2 was developed. Second, graphically represented RI percentiles and annual RIs covering 0-18 years were computed (cohort of healthy children [1181 girls and 543 boys]). Subsequently, RIs were compared with published data by systematic searches.

RESULTS

Lower limit of quantification was 11 pmol/L, indicating high sensitivity. Estradiol first peaked during mini-puberty in both sexes (girls up to 192 pmol/L; boys up to 225 pmol/L). As could be expected, girls showed higher pubertal E2 (up to 638 pmol/L). However, boys' RIs (up to 259 pmol/L) overlapped considerably. We found 4 studies in the literature that also used LC-MS/MS to determine E2 and published RIs for the complete pediatric age range. Reference intervals varied considerably. Pre-pubertal and pubertal phases were present in all studies. Higher E2 during the time of mini-puberty in both sexes was documented in 3 studies including ours.

CONCLUSIONS

Variability of RIs for E2 between studies illustrates the importance of laboratory-specific RIs despite using a LC-MS/MS reference method. In boys, the striking E2 peak during mini-puberty as well as high pubertal E2 without phenotypic estrogenization in regular male puberty indicates that the role of E2 in children and, especially in boys, requires better functional understanding.

Estrogen sulfotransferase and sulfatase in steroid homeostasis, metabolic disease, and cancer

Sulfation and desulfation of steroids are opposing processes that regulate the activation, metabolism, excretion, and storage of steroids, which account for steroid homeostasis. Steroid sulfation and desulfation are catalyzed by cytosolic sulfotransferase and steroid sulfatase, respectively. By modifying and regulating steroids, cytosolic sulfotransferase (SULT) and steroid sulfatase (STS) are also involved in the pathophysiology of steroid-related diseases, such as hormonal dysregulation, metabolic disease, and cancer. The estrogen sulfotransferase (EST, or SULT1E1) is a typical member of the steroid SULTs. This review is aimed to summarize the roles of SULT1E1 and STS in steroid homeostasis and steroid-related diseases.

Synthesis and Biological Evaluation of Chalconesulfonamides: En Route to Proapoptotic Agents with Antiestrogenic Potency

Breast and other estrogen receptor α-positive cancers tend to develop resistance to existing drugs. Chalcone derivatives possess anticancer activity based on their ability to form covalent bonds with targets acting as Michael acceptors. This study aimed to evaluate the anticancer properties of a series of chalcones (7a-l) with a sulfonamide group attached to the vinyl ketone moiety. Chalconesulfonamides showed a potent antiproliferative effect at low micromolar concentrations against several cancer cell lines, including ERα-positive 4-hydroxytamoxifen-resistant MCF7/HT2. Immunoblotting of samples treated with the lead compound 7e revealed its potent antiestrogenic activity (ERα/GREB1 axis) and induction of PARP cleavage (an apoptosis marker) in breast cancer cells. The obtained compounds represent a promising basis for further development of targeted drugs blocking hormone pathways in cancer cells.

Endocrine Disruptors and Estrogens in Human Prostatic Tissue

Endocrine disruptors (EDs) are ubiquitous substances both in the environment and everyday products that interfere with the hormonal system. Growing evidence demonstrates their adverse effects on the organism, including the reproductive system and the prostate, owing to their (anti)estrogenic or antiandrogenic effects. Since EDs can interact with steroid hormone actions on-site, understanding the levels of intraprostatic EDs in conjunction with steroids may hold particular significance. The aim of this study was to develop and validate a method for determining estrogens, various groups of EDs (bisphenols, parabens, oxybenzone and nonylphenol) and phytoestrogens in their unconjugated and conjugated forms in prostate tissue by liquid chromatography-tandem mass spectrometry, and subsequently analyze 20 human prostate tissue samples. The method enabled 20 compounds to be analyzed: estrogens (estrone, estradiol, estriol), bisphenols (bisphenol A- BPA, BPS, BPF, BPAF, BPAP, BPZ, BPP), parabens (methyl-, ethyl-, propyl-, butyl-, benzyl- paraben), oxybenzone, nonylphenol and phytoestrogens (daidzein, genistein, equol) with LLOQs between 0.017-2.86 pg/mg of tissue. The most frequently detected EDs in prostate tissues were propylparaben (conjugated and unconjugated forms in 100 % of tissues), methylparaben (unconjugated in 45 % and conjugated in 100 %), ethylparaben (unconjugated in 25 % and conjugated in 100 % BPA (unconjugated in 35 % and conjugated in 60 % and oxybenzone (both forms in 45 % To the best of our knowledge, this is the first study detecting EDs, phytoestrogens and estriol conjugate (E3C) in the prostate. E3C was the most abundant estrogen in prostatic tissue. This highlights the need for further explorations into estrogen metabolism within the prostate.

Estrogen receptor expression is modulated in human and mouse prostate epithelial cells during cancer progression

Substantial data posit estrogen receptors (ERs) as promising targets for prostate cancer (PCa) therapeutics. However, the trials on assessing the chemo-preventive or therapeutic potential of ER targeting drugs or selective estrogen receptor modulators (SERMs) have not yet established their clinical benefits. This could be ascribed to a possible modulation in the ER expression during PCa progression. Further it is warranted to test various ER targeting drugs in appropriate preclinical models that simulate human ER expression pattern during PCa progression. The study was undertaken to revisit the existing data on the epithelial ER expression pattern in human cancerous prostates and experimentally determine whether these patterns are replicated in TRAMP (Transgenic Adenocarcinoma of Mouse Prostate) mice, a model for human PCa. Estradiol (E2) binding to the plasma membrane of the epithelial cells and its modulation during the PCa progression in TRAMP were also investigated. A reassessment of the existing data revealed a trend towards downregulation in the epithelial expression of wild-type ESR1 transcripts in high-grade PCa, compared to non-cancerous prostate in humans. Next, epithelial cell-enriched populations from TRAMP prostates (TP) displaying low-grade prostatic intraepithelial neoplasia (LGPIN), high-grade PIN (HGPIN), HGPIN with well-differentiated carcinoma (PIN + WDC), WDC (equivalent to grade 2/3 human PCa), and poorly-differentiated carcinoma (PDC-equivalent to grade 4/5 human PCa) revealed significantly higher Esr1 and Esr2 levels in HGPIN and significantly reduced levels in WDC, compared to respective age-matched control prostates. These patterns for the nuclear ERs were similar to the trend shown by E2 binding to the plasma membrane of the epithelial cells during PCa progression in TRAMP. E2 binding to epithelial cells (EpCAM+), though significantly higher in TPs displaying LGPIN, decreased significantly as the disease progressed to WDC. The study highlights a reduction in the epithelial ESR level with the PCa progression and this pattern was evident in both humans and TRAMP. These observations may have major implications in refining PCa therapeutics targeting ER.

Investigating the Factors Associated with the Level of Expression of Estrogen and Progesterone Receptors in Patients Suffering from Colorectal Cancer

Background

The present study was performed to investigate the factors related to the expression level of estrogen and progesterone receptor in patients with colorectal cancer. Material and Methods. This crosssectional study was performed on 54 patients suffering from colorectal cancer referring to Imam Reza Hospital in Birjand during 2018-2019. After the biopsy performed during surgery, the specimen was sent for immunohistochemistry, and the status of receptors was determined. Eventually, the data were analyzed by SPSS 22.

Results

Out of the 54 patients studied, 64.8% were male. The mean age of the patients was 62.28 ± 14.03 years. The level of expression of beta-estrogen receptors and progesterone receptors had a significant relationship with age, consuming drugs of abuse, and familial history (P = 0.001). Also, the level of expression of estrogen and progesterone receptors of patients with a more advanced stage of cancer was significantly lower (P = 0.001).

Conclusion

The extent of expression of estrogen and progesterone receptors affects the progression and prognosis of disease. Thus, through hormone therapy, a step can be taken to reduce the progression and even to treat colorectal cancer.

Combined Effects of Different Endocrine-Disrupting Chemicals (EDCs) on Prostate Gland

Endocrine-disrupting chemicals (EDCs) belong to a heterogeneous class of environmental pollutants widely diffused in different aquatic and terrestrial habitats. This implies that humans and animals are continuously exposed to EDCs from different matrices and sources. Moreover, pollution derived from anthropic and industrial activities leads to combined exposure to substances with multiple mechanisms of action on the endocrine system and correlated cell and tissue targets. For this reason, specific organs, such as the prostate gland, which physiologically are under the control of hormones like androgens and estrogens, are particularly sensitive to EDC stimulation. It is now well known that an imbalance in hormonal regulation can cause the onset of various prostate diseases, from benign prostate hyperplasia to prostate cancer. In this review, starting with the description of normal prostate gland anatomy and embryology, we summarize recent studies reporting on how the multiple and simultaneous exposure to estrogenic and anti-androgenic compounds belonging to EDCs are responsible for an increase in prostate disease incidence in the human population.

EDCs and male urogenital cancers

Male sex determination and sexual differentiation occur between 6-12 weeks of gestation. During the "male programming window" the fetal testes start to produce testosterone that initiates the development of the male reproductive tract. Exposure to endocrine disrupting chemicals (EDCs) able to mimic or disrupt steroid hormone actions may disrupt testicular development and adversely impact reproductive health at birth, during puberty and adulthood. The testicular dysgenesis syndrome (TDS) occurs as a result inhibition of androgen action on fetal development preceding Sertoli and Leydig cell dysfunction and may result from direct or epigenetic effects. Hypospadias, cryptorchidism and poor semen quality are elements of TDS, which may be considered a risk factor for testicular germ cell cancer (TGCC). Exposure to estrogen or estrogenic EDCs results in developmental estrogenization/estrogen imprinting in the rodent for prostate cancer (PCa). This can disrupt prostate histology by disorganization of the epithelium, prostatic intraepithelial neoplasia (PIN) lesions, in particular high-grade PIN (HGPIN) lesions which are precursors of prostatic adenocarcinoma. These defects persist throughout the lifespan of the animal and later in life estrogen exposure predispose development of cancer. Exposure of pregnant dams to vinclozolin, a competitive anti-androgen, and results in prominent, focal regions of inflammation in all exposed animals. The inflammation closely resembles human nonbacterial prostatitis that occurs in young men and evidence indicates that inflammation plays a central role in the development of PCa. In conclusion, in utero exposure to endocrine disrupters may predispose to the development of TDS, testicular cancer (TCa) and PCa and are illustrations of Developmental Origins of Health and Disease (DOHaD).

Steroid Sulphatase and Its Inhibitors: Past, Present, and Future

Steroid sulphatase (STS), involved in the hydrolysis of steroid sulphates, plays an important role in the formation of both active oestrogens and androgens. Since these steroids significantly impact the proliferation of both oestrogen- and androgen-dependent cancers, many research groups over the past 30 years have designed and developed STS inhibitors. One of the main contributors to this field has been Prof. Barry Potter, previously at the University of Bath and now at the University of Oxford. Upon Prof. Potter's imminent retirement, this review takes a look back at the work on STS inhibitors and their contribution to our understanding of sulphate biology and as potential therapeutic agents in hormone-dependent disease. A number of potent STS inhibitors have now been developed, one of which, Irosustat (STX64, 667Coumate, BN83495), remains the only one to have completed phase I/II clinical trials against numerous indications (breast, prostate, endometrial). These studies have provided new insights into the origins of androgens and oestrogens in women and men. In addition to the therapeutic role of STS inhibition in breast and prostate cancer, there is now good evidence to suggest they may also provide benefits in patients with colorectal and ovarian cancer, and in treating endometriosis. To explore the potential of STS inhibitors further, a number of second- and third-generation inhibitors have been developed, together with single molecules that possess aromatase-STS inhibitory properties. The further development of potent STS inhibitors will allow their potential therapeutic value to be explored in a variety of hormone-dependent cancers and possibly other non-oncological conditions.

Estrogen and Progesterone Expression in Colorectal Carcinoma: A Clinicopathological Study

Sex steroids have been suggested to influence colorectal cancer (CRC) carcinogenesis. Also, exposure to exogenous hormones might contribute to its incidence. This study conducted to evaluate ER and PR expression as a prognostic factor in patients with CRC attending Sohag University Hospital (SUH) and Sohag Cancer Center (SCC). Materials and Methods: Tumor samples tested for Estrogen receptor (ER) / progesterone receptor (PR) expression using immunohistochemical staining (IHC). Association of this expression with overall survival (OS), disease-free survival (DFS) and progression-free survival (PFS) were evaluated. Results: Thirty out of 50 CRC tissues were evaluable for hormone receptor expression. Expression of both ER and PR was cytoplasmic. ER and PR expressions were 60% and 76.66%, respectively. There was a significant difference between loss of ER expression and depth of invasion (p= 0.01). Also, ER and PR negative expression cases were significantly at higher risk for progression (p= 0.03; 0.009 respectively). High levels of ER and PR expression were associated with higher cumulative PFS at one year and at the end of follow up time (p=0.01; 0..02 respectively); however this did not reach statistical significance on Cox proportional hazards regression analysis for progression or OS (p= 0.05; HR= 0.22; p=0.5; HR=0.67 respectively) for ER level and (p=0.07; HR=0.22; p=0.6; HR=0.72 respectively) for PR level. Conclusions: This study suggests that lower ER/PR expression levels were associated with more extensive CRC primary tumors and poorer prognosis. These data suggest that ER/PR expression might possess a prognostic value for CRC cases.

New insights of CYP1A in endogenous metabolism: a focus on single nucleotide polymorphisms and diseases

Cytochrome P450 1A (CYP1A), one of the major CYP subfamily in humans, not only metabolizes xenobiotics including clinical drugs and pollutants in the environment, but also mediates the biotransformation of important endogenous substances. In particular, some single nucleotide polymorphisms (SNPs) for CYP1A genes may affect the metabolic ability of endogenous substances, leading to some physiological or pathological changes in humans. This review first summarizes the metabolism of endogenous substances by CYP1A, and then introduces the research progress of CYP1A SNPs, especially the research related to human diseases. Finally, the relationship between SNPs and diseases is discussed. In addition, potential animal models for CYP1A gene editing are summarized. In conclusion, CYP1A plays an important role in maintaining the health in the body.

Comparison of the roles of estrogens and androgens in breast cancer and prostate cancer

Breast cancer (BC) and prostate cancer (PC) are the second most common malignant tumors in women and men in western countries, respectively. The risks of death are 14% for BC and 9% for PC. Abnormal estrogen and androgen levels are related to carcinogenesis of the breast and prostate. Estradiol stimulates cancer development in BC. The effect of estrogen on PC is concentration-dependent, and estrogen can regulate androgen production, further affecting PC. Estrogen can also increase the risk of androgen-induced PC. Androgen has dual effects on BC via different metabolic pathways, and the role of the androgen receptor (AR) in BC also depends on cell subtype and downstream target genes. Androgen and AR can stimulate both primary PC and castration-resistant PC. Understanding the mechanisms of the effects of estrogen and androgen on BC and PC may help us to improve curative BC and PC treatment strategies.

Genome-Wide Analysis of Low Dose Bisphenol-A (BPA) Exposure in Human Prostate Cells

Endocrine disrupting compounds (EDCs) have the potential to cause adverse effects on wild-life and human health. Two important EDCs are the synthetic estrogen 17α-ethynylestradiol (EE2) and bisphenol-A (BPA) both of which are xenoestrogens (XEs) as they bind the estrogen receptor and dis-rupt estrogen physiology in mammals and other vertebrates. In the recent years the influence of XEs on oncogenes, specifically in relation to breast and prostate cancer has been the subject of considerable study.

A novel long non-coding RNA from the HOXA6-HOXA5 locus facilitates colon cancer cell growth

Background

Homeobox A5 (HOXA5), a member of the HOX family, plays an important role in tumor development and morphogenesis, although opposite effects on tumorigenesis have been observed, depending on the tissue type. In this study, we aimed to investigate the role of a novel transcript from the HOXA6-HOXA5 locus in colon cancer tumorigenesis.

Methods

Human colon cancer cell lines were analyzed using next generation sequencing-based targeted mRNA capture. The effects of overexpression and silencing of HOXA5 transcripts were evaluated in vitro and using a xenograft nude mouse model.

Results

We identified three novel transcripts (HOXA5 short, long 1, and long 2) transcribed from the HOXA6-HOXA5 locus in HCT116 colon cancer cells using next generation sequencing-based targeted mRNA capture. Knockdown of HOXA5 long 1 and long 2 transcripts did not affect cell growth, while selective silencing of HOXA5 short RNA inhibited cell growth independent of HOXA5 expression. Stable overexpression of HOXA5 short RNA promoted proliferation and migration of colon cancer cell lines HCT116, DLD1, and HT-29 and accelerated tumor growth in the xenograft mouse model. In vitro translation assays suggested HOXA5 short RNA was a functional long non-coding RNA (lncRNA). Consistent with these observations, expression of HOXA5 short RNA was upregulated in advanced colon cancer tissues. Ingenuity Pathway Analysis of differentially expressed genes between HOXA5 short RNA overexpressed and silenced HCT116 cells revealed that HOXA5 short RNA preferentially modified expression of epidermal growth factor (EGF) signal-related genes. Western blot analysis demonstrated that stable overexpression of HOXA5 short RNA increased EGF receptor levels and facilitated its phosphorylation in both HCT116 cells and xenograft tumors.

Conclusions

Our results suggested that HOXA5 short RNA, a novel lncRNA, may play a crucial role in colon tumor growth through activation of EGF signaling.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5715-0) contains supplementary material, which is available to authorized users.

Tissue-specific quantification and localization of androgen and estrogen receptors in prostate cancer

Androgens and estrogens, working together, promote prostate cancer (PRCA) initiation and progression, with androgens acting via androgen receptor (AR) and estrogens acting primarily through estrogen receptor α (ERα). While the interplay between these steroid hormones has been established, the interaction between steroid hormone receptors in prostatic disease remains unstudied. The goal of this study was to objectively determine the incidence, stage specificity, and tissue/cell type specificity of AR and ERα expression, both independently and simultaneously, during the progression of PRCA. Using multiplexed immunohistochemistry and multispectral imaging analysis, AR, ERα, and smooth muscle α-actin expression was detected and quantitated in benign prostate tissue (BPT), high-grade prostatic intraepithelial neoplasia (HGPIN), PRCA, and metastasis (MET) from patient specimens (n=340). Epithelial AR expression was significantly increased in HGPIN, PRCA, and MET compared with BPT, whereas ERα expression in epithelial and stromal cells was highest in HGPIN. With analysis of AR and ERα coexpression, we identified a unique population of double-positive (AR⁺/ERα⁺) cells that increased in HGPIN specimens in both the stroma and the epithelium. Double-negative (AR^-/ERα^-) cells significantly decreased across PRCA progression, from 65% in BPT to 30% in MET. Preliminary analysis of this AR⁺/ERα⁺ population indicates potential cell type specificity in smooth muscle α-actin-negative stromal cells. This study demonstrates stage-, tissue-, and cell type-specific AR and ERα expression changes during PRCA progression, both independently and coexpressed. A more complete understanding of steroid hormones and their receptors in the initiation and progression of prostatic disease may elucidate improved strategies for PRCA prevention or therapy.

The effects of Pueraria mirifica extract, diadzein and genistein in testosterone-induced prostate hyperplasia in male Sprague Dawley rats

Pueraria mirifica (PM) is a medicinal plant native to Thailand contained high amount of phytoestrogen and possesses anticancer activity. This study reports the effect of P. mirifica extract, phytoestrogen of diadzein and genistein for its benign prostate hyperplasia properties in testosterone-induced prostate hyperplasia in male Sprague Dawley rats. The P. mirifica extract was evaluated for its total phenols, flavonoid and antioxidant activity using DPPH, FRAP and metal chelating assay. The assessment of P. mirifica, diadzein and genistein against benign prostate hyperplasia was determined in testosterone-induced prostate hyperplasia in male Sprague Dawley rats. The total phenol was higher than flavonoid but showed low antioxidant activity of DPPH, FRAP and metal chelating. The aqueous PM extract at 1000 mg/kg significantly increased testosterone levels in testosterone-induced rats by 13% while diadzein and genistein increased it by 11% and 17% respectively. However, levels of FSH, LH, triglyceride and HDL are not affected by the oral administration of PM, diadzein and genistein to the rats. Similarly, total protein, albumin, globulin, total bilirubin, conjugated bilirubin, alkaline phosphatase, alanine aminotransferase, AST, and G-glutamyltransferase showed no significant difference as compared with negative control rats. The body weight of the rats, testis, kidney and liver showed no toxic effect. The zinc content increased significantly and the zinc transporter gen of ZnT4 and ZIP4 highly expressed suggesting that the PM, diadzein and genistein plays essential role in modulating prostate zinc homeostasis. Similarly, the expression of IL-6, AR and ER was significantly reduced indicating functioning in regulation of prostate growth and acts as anti-inflammatory role in preventing BPH. In conclusion, the results indicated that PM reduced BPH and contributed to the regulation in the zinc transport expression of the prostate cells in the benign prostate hyperplasia (BPH).

A mathematical model for predicting putative association between E2/T ratio and the development of benign prostate hyperplasia in rats

Benign prostatic hyperplasia (BPH) develops more likely with increasing age and changing serum concentrations of circulating estradiol (E2) and/or testosterone (T). In this study, we explored the relationship between serum E2/T ratio and BPH risk in rats by fitting a mathematical model. A total of 176 rats were randomized to one of the following treatment groups: normal control, castrated control, and 20 more groups of castrated animals treated with increasing dose combinations of T and E2, once daily for 30 days. Serial blood samples were obtained to determine serum T and E2 levels by magnetic bead enzyme-linked immunosorbent assay. Prostate tissue was taken to measure prostate volume. MATLAB software was used to simulate the relationship between prostate/body weight ratio (PBR) and E2/T ratio with a mathematical equation. The values of PBR, E2 and T in the treatment groups were significantly higher than those in the control groups. Stepwise regression showed that PBR was a function of E2 and T. PBR = -0.1782 + 0.0081 E2 + 0.063 T - 0.6 × 10-5 E22 - 0.28 × 10-3 T2. E2/T ratio change may be one of the risk factors for PBR, which is associated with the development of BPH.

Selenium and Sex Steroid Hormones in a U.S. Nationally Representative Sample of Men: A Role for the Link between Selenium and Estradiol in Prostate Carcinogenesis?

BACKGROUND

Given the recent findings from pooled studies about a potential inverse association between selenium levels and prostate cancer risk, this cross-sectional study aimed to investigate the association between serum selenium and serum concentrations of sex steroid hormones including estradiol in a nationally representative sample of U.S. men to investigate one mechanism by which selenium may influence prostate cancer risk.

METHODS

The study included 1,420 men ages 20 years or older who participated in the Third National Health and Nutrition Examination Survey between 1988 and 1994. We calculated age/race-ethnicity-adjusted and multivariable-adjusted geometric mean serum concentrations of total and estimated free testosterone and estradiol, androstanediol glucuronide, and sex hormone binding globulin, and compared them across quartiles of serum selenium.

RESULTS

Adjusting for age, race/ethnicity, smoking status, serum cotinine, household income, physical activity, alcohol consumption, and percent body fat, mean total estradiol [e.g., Q1, 38.00 pg/mL (95% confidence interval (CI), 36.03-40.08) vs. Q4, 35.29 pg/mL (95% CI, 33.53-37.14); P _trend = 0.050] and free estradiol [e.g., Q1, 0.96 pg/mL (95% CI, 0.92-1.01) vs. Q4, 0.90 (95% CI, 0.85-0.95); P _trend = 0.065] concentrations decreased over quartiles of selenium. Stratification by smoking and alcohol consumption, showed that the latter observation was stronger for never smokers (P _interaction = 0.073) and those with limited alcohol intake (P _interaction = 0.017). No associations were observed for the other sex steroid hormones studied.

CONCLUSIONS

Our findings suggests that a possible mechanism by which selenium may be protective for prostate cancer is related to estrogen.

IMPACT

Further studies of longitudinal measurements of serum and toenail selenium in relation to serum measurements of sex steroid hormones are needed.

Associations between polymorphisms in genes related to estrogen metabolism and function and prostate cancer risk: results from the Prostate Cancer Prevention Trial

Substantial preclinical data suggest estrogen's carcinogenic role in prostate cancer development; however, epidemiological evidence based on circulating estrogen levels is largely null. Compared with circulating estrogen, the intraprostatic estrogen milieu may play a more important role in prostate carcinogenesis. Using a nested case-control design in the Prostate Cancer Prevention Trial (PCPT), we examined associations of genetic variants of genes that are involved in estrogen synthesis, metabolism and function with prostate cancer risk. A total of 25 potentially functional single nucleotide polymorphisms (SNPs) in 13 genes (PGR, ESR1, ESR2, CYP17A1, HSD17B1, CYP19A1, CYP1A1, CYP1B1, COMT, UGT1A6, UGT1A10, UGT2B7, UGT2B15) were examined in whites only. Controls (n = 1380) were frequency matched to cases on age, PCPT treatment arm, and family history (n = 1506). Logistic regression models adjusted for age and family history were used to estimate odds ratios (OR) and 95% confidence intervals (CI) separately in the placebo and finasteride arms. SNPs associated with prostate cancer risk differed by treatment arm. The associations appeared to be modified by circulating estrogen and androgen levels. CYP19A1 was the only gene harboring SNPs that were significantly associated with risk in both the placebo and finasteride arms. Haplotype analysis with all three CYP19A1 SNPs genotyped (rs700518, rs2445765, rs700519) showed that risk-allele haplotypes are associated with the increased prostate cancer risk in both arms when comparing with the non-risk allele haplotype. In conclusion, associations between SNPs in estrogen-related genes and prostate cancer risk are complex and may be modified by circulating hormone levels and finasteride treatment.

New Insights in Prostate Cancer Development and Tumor Therapy: Modulation of Nuclear Receptors and the Specific Role of Liver X Receptors

Prostate cancer (PCa) incidence has been dramatically increasing these last years in westernized countries. Though localized PCa is usually treated by radical prostatectomy, androgen deprivation therapy is preferred in locally advanced disease in combination with chemotherapy. Unfortunately, PCa goes into a castration-resistant state in the vast majority of the cases, leading to questions about the molecular mechanisms involving the steroids and their respective nuclear receptors in this relapse. Interestingly, liver X receptors (LXRα/NR1H3 and LXRβ/NR1H2) have emerged as new actors in prostate physiology, beyond their historical roles of cholesterol sensors. More importantly LXRs have been proposed to be good pharmacological targets in PCa. This rational has been based on numerous experiments performed in PCa cell lines and genetic animal models pointing out that using selective liver X receptor modulators (SLiMs) could actually be a good complementary therapy in patients with a castration resistant PCa. Hence, this review is focused on the interaction among the androgen receptors (AR/NR3C4), estrogen receptors (ERα/NR3A1 and ERβ/NR3A2), and LXRs in prostate homeostasis and their putative pharmacological modulations in parallel to the patients' support.

Epithelial-mesenchymal transition in prostate cancer: an overview

Prostate cancer is a main urological disease associated with significant morbidity and mortality. Radical prostatectomy and radiotherapy are potentially curative for localized prostate cancer, while androgen deprivation therapy is the initial systemic therapy for metastatic prostate disease. However, despite temporary response, most patients relapse and evolve into castration resistant cancer.

Epithelial-mesenchymal transition (EMT) is a complex gradual process that occurs during embryonic development and/or tumor progression. During this process, cells lose their epithelial characteristics and acquire mesenchymal features. Increasing evidences indicate that EMT promotes prostate cancer metastatic progression and it is closely correlated with increased stemness and drug resistance.

In this review, we discuss the main molecular events that directly or indirectly govern the EMT program in prostate cancer, in order to better define the role and the mechanisms underlying this process in prostate cancer progression and therapeutic resistance.

Combinatorial strategy of epigenetic and hormonal therapies: A novel promising approach for treating advanced prostate cancer

AIMS

Estrogens act as key factors in prostate biology, cellular proliferation and differentiation as well as cancer development and progression. The expression of estrogen receptor (ER)-β appears to be lost during prostate cancer progression through hypermethylation mechanism. Epigenetic drugs such as 5-aza-2'-deoxycytidine (5-AZAC) and Trichostatin A (TSA) showed efficacy in restoring ERβ expression in prostate cancer cells. This study was designed to explore the potential anti-carcinogenic effects resulting from re-expressing ERβ1 using 5-AZAC and/or TSA, followed by its stimulation with Diarylpropionitrile (DPN), a selective ERβ1 agonist, in prostate cancer cell line PC-3.

MAIN METHODS

Cells were treated with 5-AZAC, TSA, DPN and their combination. Subsequently, they were subjected to proliferation assays, determinations of ERβ1 expression, protein levels of active caspase-3, cyclin D1, β-catenin and VEGF.

KEY FINDINGS

Treatment with these drugs exhibited an increase in ERβ1 expression to different extents as well as active caspase-3 levels. Meanwhile, a significant reduction in cyclin D1, VEGF and β-catenin levels was achieved as compared to the vehicle control group (p < 0.05). Interestingly, the triple combination regimen led to the most prominent anti-tumor responses in terms of increased apoptosis, reduced proliferation as well as angiogenesis.

SIGNIFICANCE

The results support the notion that ERβ1 acts as a tumor suppressor protein and suggest that sequential ERβ1 expression and activation can offer significant anti-tumor responses. The study highlights that the strategy of merging epigenetic and hormonal therapies may be beneficial in treating advanced prostate cancer.

Recent advances on bisphenol-A and endocrine disruptor effects on human prostate cancer

Endocrine disrupting chemicals (EDCs) are man-made substances widespread in the environment that include, among many others, bisphenol A (BPA), organochlorinated pesticides and hormone derivatives detectable in meat from animals raised in concentrated animal feeding operations. Increasing evidence indicates that EDCs have a negative impact on human health as well as on male and female fertility. They may also be associated with some endocrine diseases and increased incidence of breast and prostate cancer. This review aims to summarize available data on the (potential) impact of some common EDCs, focusing particularly on BPA, prostate cancer and their mechanisms of action. These compounds interfere with normal hormone signal pathway transduction, resulting in prolonged exposure of receptors to stimuli or interference with cellular hormone signaling in target cells. Understanding the effects of BPA and other EDCs as well as their molecular mechanism(s) may be useful in sensitizing the scientific community and the manufacturing industry to the importance of finding alternatives to their indiscriminate use.

Estradiol promotes epithelial-to-mesenchymal transition in human benign prostatic epithelial cells

BACKGROUND

Epithelial-to-mesenchymal transition (EMT) is involved in pathogenesis of human benign prostatic hyperplasia (BPH). Estrogenic signaling pathways may stimulate the induction of EMT. However, the details of estradiol (E2) and estrogen receptors (ERs) effects on EMT, as well as E2-induced modulation of benign prostatic epithelial cell phenotype in vitro have not been completely clarified.

METHODS

The effects of E2 on EMT markers and cytokeratins (CKs) expression were evaluated in benign epithelial cell lines BPH-1 and RWPE-1, which were cultured both in two-dimensional (2D) culture and three-dimensional (3D) culture model using hanging drop technique or 3D Matrigel model. ER antagonist, ICI182,780, was used to confirm the regulatory effects of E2 on EMT and phenotypic modulation. In 3D culture, immunohistochemical stainings were performed to detect the specific phenotype of cells that underwent EMT in acinar-like spheroids formed by RWPE-1. To illustrate the exact function of ERs in E2-induced EMT and phenotypic modulation, specific short interfering RNAs (siRNAs), and agonists were used to knockdown or activate individual ERs, respectively.

RESULTS

E2-induced EMT was observed both in 2D and 3D culture, with related regulation of EMT markers expression at both mRNA and protein level. In addition, E2 down-regulated luminal cell type markers CK18 and CK8 and up-regulated basal cell type markers CK5 and CK14. E2 also increased intermediate type markers CK15 and CK17, while it attenuated CK19 in 3D culture. ICI182,780 blocked E2-induced EMT and cell phenotypic switching. In 3D Matrigel culture, Vimentin was co-expressed with ERα and CK17, as well as with SMemb, which is related to cell status switching and proliferation. Knockdown of ERα but not GPR30 inhibited EMT, while ERβ knockdown facilitated EMT process. Knockdown of ERα blocked E2-induced EMT both in RWPE-1 and BPH-1. MRNA expression of EMT markers was stimulated by ERα-specific agonist PPT and inhibited by ERβ-specific agonist DPN.

CONCLUSIONS

Estrogenic effect mediated by ERα can promote EMT. E2 is also an inductive factor of cell phenotypic switching. Cell type modulation is associated with E2-induced EMT in benign prostatic epithelial cells. Taken together the results support a contribution of estrogens to the pathogenesis of BPH in elderly men.

Dual action of high estradiol doses on MNU-induced prostate neoplasms in a rodent model with high serum testosterone: Protective effect and emergence of unstable epithelial microenvironment

BACKGROUND

Estrogens are critical players in prostate growth and disease. Estrogen therapy has been the standard treatment for advanced prostate cancer for several decades; however, it has currently been replaced by alternative anti-androgenic therapies. Additionally, studies of its action on prostate biology, resulting from an association between carcinogens and estrogen, at different stages of life are scarce or inconclusive about its protective and beneficial role on induced-carcinogenesis. Thus, the aim of this study was to determine whether estradiol exerts a protective and/or stimulatory role on N-methyl-N-nitrosurea-induced prostate neoplasms.

METHODS

We adopted a rodent model that has been used to study induced-prostate carcinogenesis: the Mongolian gerbil. We investigated the occurrence of neoplasms, karyometric patterns, androgen and estrogen receptors, basal cells, and global methylation status in ventral and dorsolateral prostate tissues.

RESULTS

Histopathological analysis showed that estrogen was able to slow tumor growth in both lobes after prolonged treatment. However, a true neoplastic regression was observed only in the dorsolateral prostate. In addition to the protective effects against neoplastic progression, estrogen treatment resulted in an epithelium that exhibited features distinctive from a normal prostate, including increased androgen-insensitive basal cells, high androgens and estrogen receptor positivity, and changes in DNA methylation patterns.

CONCLUSIONS

Estrogen was able to slow tumor growth, but the epithelium exhibited features distinct from a normal prostatic epithelium, and this unstable microenvironment could trigger lesion recurrence over time.

Food components and contaminants as (anti)androgenic molecules

Androgens, the main male sex steroids, are the critical factors responsible for the development of the male phenotype during embryogenesis and for the achievement of sexual maturation and puberty. In adulthood, androgens remain essential for the maintenance of male reproductive function and behavior. Androgens, acting through the androgen receptor (AR), regulate male sexual differentiation during development, sperm production beginning from puberty, and maintenance of prostate homeostasis. Several substances present in the environment, now classified as endocrine disruptors (EDCs), strongly interfere with androgen actions in reproductive and non-reproductive tissues. EDCs are a heterogeneous group of xenobiotics which include synthetic chemicals used as industrial solvents/lubricants, plasticizers, additives, agrochemicals, pharmaceutical agents, and polyphenols of plant origin. These compounds are even present in the food as components (polyphenols) or food/water contaminants (pesticides, plasticizers used as food packaging) rendering the diet as the main route of exposure to EDCs for humans. Although huge amount of literature reports the (anti)estrogenic effects of different EDCs, relatively scarce information is available on the (anti)androgenic effects of EDCs. Here, the effects and mechanism of action of phytochemicals and pesticides and plasticizers as possible modulators of AR activities will be reviewed taking into account that insight derived from principles of endocrinology are required to estimate EDC consequences on endocrine deregulation and disease.

A comprehensive review of regulatory test methods for endocrine adverse health effects

Development of new endocrine disruption-relevant test methods has been the subject of intensive research efforts for the past several decades, prompted in part by mandates in the 1996 Food Quality Protection Act (FQPA). While scientific understanding and test methods have advanced, questions remain on whether current scientific methods are capable of adequately addressing the complexities of the endocrine system for regulatory health and ecological risk assessments. The specific objective of this article is to perform a comprehensive, detailed evaluation of the adequacy of current test methods to inform regulatory risk assessments of whether a substance has the potential to perturb endocrine-related pathways resulting in human adverse effects. To that end,  approximately 42 existing test guidelines (TGs) were considered in the evaluation of coverage for endocrine-related adverse effects. In addition to evaluations of whether test methods are adequate to capture endocrine-related effects, considerations of further enhancements to current test methods, along with the need to develop novel test methods to address existing test method gaps are described. From this specific evaluation, up to 35 test methods are capable of informing whether a chemical substance perturbs known endocrine related biological pathways. Based on these findings, it can be concluded that current validated test methods are adequate to discern substances that may perturb the endocrine system, resulting in an adverse health effect. Together, these test methods predominantly form the core data requirements of a typical food-use pesticide registration submission. It is recognized, however, that the current state of science is rapidly advancing and there is a need to update current test methods to include added enhancements to ensure continued coverage and public health and environmental protection.

Acute exposure to bisphenol A and cadmium causes changes in the morphology of gerbil ventral prostates and promotes alterations in androgen-dependent proliferation and cell death

Bisphenol A (BPA) and cadmium (Cd) are environmental pollutants that are implicated in potential reproductive effects, including damage to the prostate gland. Their action during puberty requires analysis to determine the relationship of these compounds with the testosterone peak that occurs during this phase. This study evaluated whether exposure to BPA and Cd during puberty can cause changes in the morphology, proliferation and cell death and androgen receptor (AR) immunostaining of the ventral prostates of normal and castrated male gerbils (Meriones unguiculatus), considering an acute exposure to the chemicals and evaluation after short (52d) and long (120d) periods. Generally, morphometric-stereological results demonstrated that administration of BPA and Cd (individually or in combination) increased epithelial height, smooth muscle layer (SML) thickness and nuclear area and perimeter, and that these parameters were reduced in castrated animals. In addition, these groups showed important inflammatory processes but not prostate lesions. The proliferation/death rates of prostatic cells obtained by PCNA and TUNEL immunostaining demonstrated increased cell death in the 52d groups; in contrast, the gland acquired a more proliferative nature in the 120d groups. AR immunostaining showed that BPA and Cd compounds interact with ARs in different ways depending on the evaluated period and the hormonal profile of the animal. We conclude that BPA and cadmium are important agents in changing the morphology, proliferation and death of prostatic cells, in addition to interacting with ARs in different patterns. © 2015 Wiley Periodicals, Inc. Environ Toxicol 32: 48-61, 2017.

Estrogen and estrogen receptor alpha promotes malignancy and osteoblastic tumorigenesis in prostate cancer

The role of estrogen signaling in regulating prostate tumorigenesis is relatively underexplored. Although, an increasing body of evidence has linked estrogen receptor beta (ERβ) to prostate cancer, the function of estrogen receptor alpha (ERα) in prostate cancer is not very well studied. We have discovered a novel role of ERα in the pathogenesis of prostate tumors. Here, we show that prostate cancer cells express ERα and estrogen induces oncogenic properties in prostate cancer cells through ERα. Importantly, ERα knockdown in the human prostate cancer PacMetUT1 cells as well as pharmacological inhibition of ERα with ICI 182,780 inhibited osteoblastic lesion formation and lung metastasis in vivo. Co-culture of pre-osteoblasts with cancer cells showed a significant induction of osteogenic markers in the pre-osteoblasts, which was attenuated by knockdown of ERα in cancer cells suggesting that estrogen/ERα signaling promotes crosstalk between cancer and osteoblastic progenitors to stimulate osteoblastic tumorigenesis. These results suggest that ERα expression in prostate cancer cells is essential for osteoblastic lesion formation and lung metastasis. Thus, inhibition of ERα signaling in prostate cancer cells may be a novel therapeutic strategy to inhibit the osteoblastic lesion development as well as lung metastasis in patients with advanced prostate cancer.

In touch with your feminine side: how oestrogen metabolism impacts prostate cancer

Prostate cancer is the primary cancer in males, with increasing global incidence rates making this malignancy a significant healthcare burden. Androgens not only promote normal prostate maturity but also influence the development and progression of prostate cancer. Intriguingly, evidence now suggests endogenous and exogenous oestrogens, in the form of phytoestrogens, may be equally as relevant as androgens in prostate cancer growth. The prostate gland has the molecular mechanisms, catalysed by steroid sulphatase (STS), to unconjugate and utilise circulating oestrogens. Furthermore, prostate tissue also expresses enzymes essential for local oestrogen metabolism, including aromatase (CYP19A1) and 3β- and 17β-hydroxysteroid dehydrogenases. Increased expression of these enzymes in malignant prostate tissue compared with normal prostate indicates that oestrogen synthesis is favoured in malignancy and thus may influence tumour progression. In contrast to previous reviews, here we comprehensively explore the epidemiological and scientific evidence on how oestrogens impact prostate cancer, particularly focusing on pre-receptor oestrogen metabolism and subsequent molecular action. We analyse how molecular mechanisms and metabolic pathways involved in androgen and oestrogen synthesis intertwine to alter prostate tissue. Furthermore, we speculate on whether oestrogen receptor status in the prostate affects progression of this malignancy.

Actions of Estrogenic Endocrine Disrupting Chemicals on Human Prostate Stem/Progenitor Cells and Prostate Carcinogenesis

Substantial evidences from epidemiological and animal-based studies indicate that early exposure to endocrine disrupting chemicals (EDCs) during the developmental stage results in a variety of disorders including cancer. Previous studies have demonstrated that early estrogen exposure results in life-long reprogramming of the prostate gland that leads to an increased incidence of prostatic lesions with aging. We have recently documented that bisphenol A (BPA), one of the most studied EDCs with estrogenic activity has similar effects in increasing prostate carcinogenic potential, supporting the connection between EDCs exposure and prostate cancer risk. It is well accepted that stem cells play a crucial role in development and cancer. Accumulating evidence suggest that stem cells are regulated by extrinsic factors and may be the potential target of hormonal carcinogenesis. Estrogenic EDCs which interfere with normal hormonal signaling may perturb prostate stem cell fate by directly reprogramming stem cells or breaking down the stem cell niche. Transformation of stem cells into cancer stem cells may underlie cancer initiation accounting for cancer recurrence, which becomes a critical therapeutic target of cancer management. We therefore propose that estrogenic EDCs may influence the development and progression of prostate cancer through reprogramming and transforming the prostate stem and early stage progenitor cells. In this review, we summarize our current studies and have updated recent advances highlighting estrogenic EDCs on prostate carcinogenesis by possible targeting prostate stem/progenitor cells. Using novel stem cell assays we have demonstrated that human prostate stem/progenitor cells express estrogen receptors (ER) and are directly modulated by estrogenic EDCs. Moreover, employing anin vivohumanized chimeric prostate model, we further demonstrated that estrogenic EDCs initiate and promote prostatic carcinogenesis in an androgen-supported environment. These findings support our hypothesis that prostate stem/progenitor cells may be the direct targets of estrogenic EDCs as a consequence of developmental exposure which carry permanent reprogrammed epigenetic and oncogenic events and subsequently deposit into cancer initiation and progression in adulthood.

Estrogen Exhibits a Biphasic Effect on Prostate Tumor Growth through the Estrogen Receptor β-KLF5 Pathway

Estrogens are effective in the treatment of prostate cancer; however, the effects of estrogens on prostate cancer are enigmatic. In this study, we demonstrated that estrogen (17β-estradiol [E2]) has biphasic effects on prostate tumor growth. A lower dose of E2 increased tumor growth in mouse xenograft models using DU145 and PC-3 human prostate cancer cells, whereas a higher dose significantly decreased tumor growth. We found that anchorage-independent apoptosis in these cells was inhibited by E2 treatment. Similarly, in vivo angiogenesis was suppressed by E2. Interestingly, these effects of E2 were abolished by knockdown of either estrogen receptor β (ERβ) or Krüppel-like zinc finger transcription factor 5 (KLF5). Ιn addition, E2 suppressed KLF5-mediated transcription through ERβ, which inhibits proapoptotic FOXO1 and proangiogenic PDGFA expression. Furthermore, we revealed that a nonagonistic ER ligand GS-1405 inhibited FOXO1 and PDGFA expression through the ERβ-KLF5 pathway and regulated prostate tumor growth without ERβ transactivation. Therefore, these results suggest that E2 biphasically modulates prostate tumor formation by regulating KLF5-dependent transcription through ERβ and provide a new strategy for designing ER modulators, which will be able to regulate prostate cancer progression with minimal adverse effects due to ER transactivation.

Application of the yeast-based reporter gene bioassay for the assessment of estrogenic activity in cow's milk from Poland

Milk contain compounds acting through the estrogen receptor signaling. The still open question whether such estrogens pose a risk for human health, encouraged us to measure the overall estrogenic activity of cow's milk in the in vitro yeast reporter bioassay. First, we assessed the ability of the bioassay to detect estrogens frequently detected in milk. The relative potencies of 16 compounds descended in the order: 17β-estradiol (17β-E2), 17α-ethinylestradiol, diethylstilbestrol, dienestrol, 17α-E2, estrone, zearalenone, estriol, equol, genistein, 17β-E2 glucuronide, bisphenol A, apigenin, daidzein. Flavone, 4-n-nonylphenol and 4-t-octylphenol shown no activity in the bioassay.The estrogenic activities of milk samples without hydrolysis were below the detection limit, whereas in 50% of the deconjugated samples they varied between 0.29 and 0.49 ng EEQ mL(-1). We also compared the estrogenic activity in raw cow's milk collected from rural and industrial locations in Poland. In our pilot study we did not observe statistically significant difference in estrogenic activities in milk collected from the two locations. We found that the daily intake of estrogens with milk may be higher than estrogen levels in human serum. Further studies are warranted to evaluate the significance of milk and dairy as a source of estrogens for humans.

Raloxifene nanomicelles reduce the growth of castrate-resistant prostate cancer

BACKGROUND

Castrate-resistant prostate cancer (CRPC) patients are characterised by a 5-year relative survival rate of ∼25-33%. Recently, our laboratory encapsulated a selective oestrogen receptor modulator, raloxifene, into poly(styrene-co-maleic acid) (SMA-raloxifene), which demonstrated superior in vitro cytotoxicity compared with free drug against several CRPC cell lines.

PURPOSE

To validate SMA-raloxifene for the management of CRPC using a mouse xenograft model.

METHODS

The internalisation and retention of micellar and free raloxifene in vitro were measured by HPLC. A PC3-CRPC xenograft model was used to compare the biodistribution of both raloxifene formulations, as well as their effect on tumour progression where mice received free raloxifene (1 or 5 mg/kg, i.v.) or SMA-raloxifene (1 mg/kg, i.v.) weekly for 4 weeks.

RESULTS

SMA-raloxifene exhibited 75% higher intracellular content compared to free drug after 48 h in PC3 cells. Biodistribution of raloxifene was 69% higher in tumours following SMA-raloxifene compared with free raloxifene. Weekly administration of 1 mg/kg free raloxifene reduced tumour progression by 20% after 4 weeks, whereas 1 mg/kg SMA-raloxifene and 5 mg/kg free raloxifene reduced progression by 40%.

CONCLUSION

Encapsulation of raloxifene increased its therapeutic potential for the management of CRPC.

MicroRNA-135b regulates ERα, AR and HIF1AN and affects breast and prostate cancer cell growth

MicroRNAs (miRNAs) regulate a wide range of cellular signaling pathways and biological processes in both physiological and pathological states such as cancer. We have previously identified miR-135b as a direct regulator of androgen receptor (AR) protein level in prostate cancer (PCa). We wanted to further explore the relationship of miR-135b to hormonal receptors, particularly estrogen receptor α (ERα). Here we show that miR-135b expression is lower in ERα-positive breast tumors as compared to ERα-negative samples in two independent breast cancer (BCa) patient cohorts (101 and 1302 samples). Additionally, the miR-135b expression is higher in AR-low PCa patient samples (47 samples). We identify ERα as a novel miR-135b target by demonstrating miR-135b binding to the 3'UTR of the ERα and decreased ERα protein and mRNA level upon miR-135b overexpression in BCa cells. MiR-135b reduces proliferation of ERα-positive BCa cells MCF-7 and BT-474 as well as AR-positive PCa cells LNCaP and 22Rv1 when grown in 2D. To identify other genes regulated by miR-135b we performed gene expression studies and found a link to the hypoxia inducible factor 1α (HIF1α) pathway. We show that miR-135b influences the protein level of the inhibitor for hypoxia inducible factor 1α (HIF1AN) and is able to bind to HIF1AN 3'UTR. Our study demonstrates that miR-135b regulates ERα, AR and HIF1AN protein levels through interaction with their 3'UTR regions, and proliferation in ERα-positive BCa and AR-positive PCa cells.

Bringing GC-MS profiling of steroids into clinical applications

Abnormalities of steroid biosynthesis and excretion are responsible for the development and prevention of endocrine disorders, such as metabolic syndromes, cancers, and neurodegenerative diseases. Due to their biochemical roles in endocrine system, qualitative and quantitative analysis of steroid hormones in various biological specimens is needed to elucidate their altered expression. Mass spectrometry (MS)-based steroid profiling can reveal the states of metabolites in biological systems and provide comprehensive insights by allowing comparisons between metabolites present in cells, tissues, or organisms. In addition, the activities of many enzymes related to steroid metabolism often lead to hormonal imbalances that have serious consequences, and which are responsible for the progress of hormone-dependent diseases. In contrast to immunoaffinity-based enzyme assays, MS-based methods are more reproducible in quantification. In particular, high-resolution gas chromatographic (GC) separation of steroids with similar chemical structures can be achieved to provide rapid and reproducible results with excellent purification. GC-MS profiling therefore has been widely used for steroid analysis, and offers the basis for techniques that can be applied to large-scale clinical studies. Recent advances in analytical technologies combined with inter-disciplinary strategies, such as physiology and bioinformatics, will help in understanding the biochemical roles of steroid hormones. Therefore, comprehensive analytical protocols in steroid analysis for different research purposes may contribute to the elucidation of complex metabolic processes relevant to steroid function in many endocrine disorders, and in the identification of diagnostic biomarkers.

A human fetal prostate xenograft model of developmental estrogenization

Prostate cancer is a common disease in older men. Rodent models have demonstrated that an early and later-life exposure to estrogen can lead to cancerous lesions and implicated hormonal dysregulation as an avenue for developing future prostate neoplasia. This study utilizes a human fetal prostate xenograft model to study the role of estrogen in the progression of human disease. Histopathological lesions were assessed in 7-, 30-, 90-, 200-, and 400-day human prostate xenografts. Gene expression for cell cycle, tumor suppressors, and apoptosis-related genes (ie, CDKN1A, CASP9, ESR2, PTEN, and TP53) was performed for 200-day estrogen-treated xenografts. Glandular hyperplasia was observed in xenografts given both an initial and secondary exposure to estradiol in both 200- and 400-day xenografts. Persistent estrogenic effects were verified using immunohistochemical markers for cytokeratin 10, p63, and estrogen receptor α. This model provides data on the histopathological state of the human prostate following estrogenic treatment, which can be utilized in understanding the complicated pathology associated with prostatic disease and early and later-life estrogenic exposures.

Estrogen receptors and their implications in colorectal carcinogenesis

Upon binding their cognate receptors, ERα (ESR1) and ERβ (ESR2), estrogens activate intracellular signaling cascades that have important consequences for cellular behavior. Historically linked to carcinogenesis in reproductive organs, estrogens have also been implicated in the pathogenesis of different cancer types of non-reproductive tissues including the colon. ERβ is the predominant estrogen receptor expressed in both normal and malignant colonic epithelium. However, during colon cancer progression, ERβ expression is lost, suggesting that estrogen signaling may play a role in disease progression. Estrogens may in fact exert an anti-tumor effect through selective activation of pro-apoptotic signaling mediated by ERβ, inhibition of inflammatory signals and modulation of the tumor microenvironment. In this review, we analyze the estrogen pathway as a possible therapeutic avenue in colorectal cancer, we report the most recent experimental evidence to explain the cellular and molecular mechanisms of estrogen-mediated protection against colorectal tumorigenesis, and we discuss future challenges and potential avenues for targeted therapy.

Deficiency of ERβ and prostate tumorigenesis in FGF8b transgenic mice

Estrogens contribute to the development and growth of the prostate and are implicated in prostate tumorigenesis. In their target tissues, estrogens mediate their effects via estrogen receptor α (ERα (ESR1)) and β (ERβ (ESR2)). Hyperplasia and decreased differentiation of epithelial cells in the prostate have been reported in ERβ knockout (BERKO) mice. Herein, we studied the effect of ERβ deficiency on prostate tumorigenesis by crossing BERKOFVB mice with prostate-targeted human fibroblast growth factor 8b transgenic (FGF8b-Tg) mice. Consistent with results described in our previous report, the prostates of 1-year-old FGF8b-Tg mice displayed stromal aberrations, prostatic intraepithelial neoplasia (mPIN) lesions, inflammation, and occasionally cancer. The prostates of BERKOFVB mice exhibited mild epithelial hypercellularity and inflammation. The prostate phenotypes of FGF8b-Tg-BERKOFVB mice closely resembled those of FGF8b-Tg mice. However, mucinous metaplasia, indicated by Goblet-like cells in the epithelium, was significantly more frequent in the prostates of FGF8b-Tg-BERKOFVB mice when compared with FGF8b-Tg mice. Furthermore, compared with FGF8b-Tg mice, there was a tendency for increased frequency of inflammation but milder hyperplasias in the prostate stroma of FGF8b-Tg-BERKOFVB mice. The expression levels of mRNAs for FGF8b-regulated genes including osteopontin (Spp1), connective tissue growth factor (Ctgf), fibroblast growth factor receptors (Fgfrs), and steroid hormone receptors and cytokines were similar in the prostates of FGF8b-Tg and FGF8b-Tg-BERKOFVB mice. Our results indicate that ERβ plays a role in the differentiation of the prostatic epithelium and, potentially, in the defensive mechanism required for protection against inflammation but do not support a direct tumor-suppressive function of ERβ in the prostate of FGF8b-Tg mice.

Expression of androgen and estrogen signaling components and stem cell markers to predict cancer progression and cancer-specific survival in patients with metastatic prostate cancer

PURPOSE

Genes of androgen and estrogen signaling cells and stem cell-like cells play crucial roles in prostate cancer. This study aimed to predict clinical failure by identifying these prostate cancer-related genes.

EXPERIMENTAL DESIGN

We developed models to predict clinical failure using biopsy samples from a training set of 46 and an independent validation set of 30 patients with treatment-naïve prostate cancer with bone metastasis. Cancerous and stromal tissues were separately collected by laser-captured microdissection. We analyzed the association between clinical failure and mRNA expression of the following genes androgen receptor (AR) and its related genes (APP, FOX family, TRIM 36, Oct1, and ACSL 3), stem cell-like molecules (Klf4, c-Myc, Oct 3/4, and Sox2), estrogen receptor (ER), Her2, PSA, and CRP.

RESULTS

Logistic analyses to predict prostate-specific antigen (PSA) recurrence showed an area under the curve (AUC) of 1.0 in both sets for Sox2, Her2, and CRP expression in cancer cells, AR and ERα expression in stromal cells, and clinical parameters. We identified 10 prognostic factors for cancer-specific survival (CSS): Oct1, TRIM36, Sox2, and c-Myc expression in cancer cells; AR, Klf4, and ERα expression in stromal cells; and PSA, Gleason score, and extent of disease. On the basis of these factors, patients were divided into favorable-, intermediate-, and poor-risk groups according to the number of factors present. Five-year CSS rates for the 3 groups were 90%, 32%, and 12% in the training set and 75%, 48%, and 0% in the validation set, respectively.

CONCLUSIONS

Expression levels of androgen- and estrogen signaling components and stem cell markers are powerful prognostic tools.

The influence of ESR1 rs9340799 and ESR2 rs1256049 polymorphisms on prostate cancer risk

Estrogen receptor 1 (ESR1) and estrogen receptor 2 (ESR2) may play a role in the development of prostate cancer. Many studies focused on ESR1 rs9340799 and ESR2 rs1256049 polymorphisms to explore associations with prostate cancer risk. These studies showed inconsistent and conflicting results. The aim of this meta-analysis was to investigate the pooled association of ESR1 rs9340799 and ESR2 rs1256049 polymorphisms with prostate cancer risk. A systematic literature search was conducted to identify related studies (up to February 2014) in several online databases including PubMed, Google Scholar, CNKI and Wanfang online libraries. A total of 16 eligible articles were enrolled in this updated meta-analysis. The result suggested that ESR1 rs9340799 polymorphism was significantly associated with prostate cancer in overall populations (GG+GA vs. AA: P = 0.002; G vs. A: P = 0.004), Caucasians (GG+GA vs. AA: P = 0.008; G vs. A: P = 0.016) and Africans (GG+GA vs. AA: P = 0.005; G vs. A: P = 0.006), but not in Asians (GG+GA vs. AA: P = 0.462; G vs. A: P = 0.665). The result also showed that there was a significant association between ESR2 rs1256049 polymorphism and prostate cancer in Caucasians (AA+AG vs. GG: P = 0.016; A vs. G: P = 0.005), but no association in overall populations (AA+AG vs. GG: P = 0.826; A vs. G: P = 0.478), Asians (AA+AG vs. GG: P = 0.177; A vs. G: P = 0.703) and Africans (AA+AG vs. GG: P = 0.847; A vs. G: P = 0.707). The cumulative meta-analysis and sensitivity analysis showed the results were robust. In conclusion, this meta-analysis indicated that ESR1 rs9340799 polymorphism was associated with prostate cancer risk in overall populations, Caucasians and Africans, while ESR2 rs1256049 polymorphism was associated with prostate cancer risk in Caucasians. However, the biological mechanisms need to be further investigated.

Estrogen receptor α in cancer-associated fibroblasts suppresses prostate cancer invasion via modulation of thrombospondin 2 and matrix metalloproteinase 3

The prostate cancer (PCa) microenvironment contains active stromal cells known as cancer-associated fibroblasts (CAF) that may play important roles in influencing tumor progression. Here we studied the role of CAF estrogen receptor alpha (ERα) and found that it could protect against PCa invasion. Immunohistochemistry on prostatectomy specimens showed that PCa patients with ERα-positive stroma had a significantly lower risk for biochemical recurrence. In vitro invasion assays further confirmed that the stromal ERα was able to reduce PCa cell invasion. Dissection of the molecular mechanism revealed that the CAF ERα could function through a CAF-epithelial interaction via selectively upregulating thrombospondin 2 (Thbs2) and downregulating matrix metalloproteinase 3 (MMP3) at the protein and messenger RNA levels. Chromatin immunoprecipitation assays further showed that ERα could bind to an estrogen response element on the promoter of Thbs2. Importantly, knockdown of Thbs2 led to increased MMP3 expression and interruption of the ERα mediated invasion suppression, providing further evidence of an ERα-Thbs2-MMP3 axis in CAF. In vivo studies using athymic nude mice injected with CWR22Rv1 (22Rv1) PCa epithelial cells and CAF cells ± ERα also confirmed that mice coimplanted with PCa cells and CAF ERα+ cells had less tumor foci in the pelvic lymph nodes, less metastases, and tumors showed less angiogenesis, MMP3, and MMP9 (an MMP3 downstream target) positive staining. Together, these data suggest that CAF ERα could play protective roles in suppressing PCa metastasis. Our results may lead to developing new and alternative therapeutic approaches to battle PCa via controlling ERα signaling in CAF.