Roles of estrogen receptor alpha and beta in modulating urothelial cell proliferation

Methylation patterns of estrogen receptor α promoter correlate with estrogen receptor α expression and clinicopathological factors in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the seventh most common type of cancer; notably, the incidence of HCC is four to eight times higher in men than women. Previous studies reported that the estrogen receptor (ER) signaling pathway is involved in the pathogenesis of HCC, although the extent of its involvement is unclear due to several conflicting reports. In the present study, tumor and paired adjacent non-cancerous tissues from 157 HCC patients were collected. Transcriptome sequencing and real-time quantitative polymerase chain reaction were used to quantify the ER α (ESR1) expression levels, and the Sequenom EpiTYPER assay was used to delineate the methylation patterns in the ESR1 promoter. We found that ESR1 expression was significantly reduced in tumor tissues (P < 0.001) compared to adjacent non-cancerous tissues. The CpG sites around the transcription start site were significantly hypermethylated in the tumor (P < 0.0001). This methylation pattern also correlated with the gene expression (P < 0.0001). Additionally, we found that the hypermethylation of ESR1 was associated with the presence of fibrous capsules (P = 1.2 × 10^-4), the absence of microvascular invasions (P = 8.0 × 10^-4), thin trabecular pattern (P = 0.025), and lower histologic gradings (P = 5.2 × 10^-3). Thus, ESR1 expression is a candidate tumor suppressor gene in HCC. Further, promoter hypermethylation may be a mechanism by which expression of ESR1 is repressed, and the extent of hypermethylation of ESR1 may be a marker for HCC status and progression.

Therapeutic effects of date fruits (Phoenix dactylifera) in the prevention of diseases via modulation of anti-inflammatory, anti-oxidant and anti-tumour activity

The current mode of treatment of various diseases based on synthetic drugs is expensive, alters genetic and metabolic pathways and also shows adverse side effects. Thus, safe and effective approach is needed to prevent the diseases development and progression. In this vista, Natural products are good remedy in the treatment/management of diseases and they are affordable and effective without any adverse effects. Dates are main fruit in the Arabian Peninsula and are considered to be one of the most significant commercial crops and also have been documented in Holy Quran and modern scientific literatures. Earlier studies have shown that constituents of dates act as potent antioxidant, anti-tumour as well as anti-inflammatory, provide a suitable alternative therapy in various diseases cure. In this review, dates fruits has medicinal value are summarized in terms of therapeutic implications in the diseases control through anti-oxidant, anti-inflammatory, anti-tumour and ant-diabetic effect.

Sex differences in the pulmonary circulation: implications for pulmonary hypertension

Pulmonary arterial hypertension (PAH), a form of pulmonary hypertension, is a complex disease of multifactorial origin. While new developments regarding pathophysiological features and therapeutic options in PAH are being reported, one important fact has emerged over the years: there is a sex difference in the incidence of this disease such that while there is a higher incidence in females, disease outcomes are much worse in males. Accordingly, recent attention has been focused on understanding the features of sex differences in the pulmonary circulation and the contributory mechanisms, particularly sex hormones and their role in the pathological and pathophysiological features of PAH. However, to date, there is no clear consensus whether sex hormones (particularly female sex steroids) are beneficial or detrimental in PAH. In this review, we highlight some of the most recent evidence regarding the influence of sex hormones (estrogen, testosterone, progesterone, dehydroepiandrosterone) and estrogen metabolites on key pathophysiological features of PAH such as proliferation, vascular remodeling, vasodilation/constriction, and inflammation, thus setting the stage for research avenues to identify novel therapeutic target for PAH as well as potentially other forms of pulmonary hypertension.

Expression of estrogen receptor α and β in esophageal squamous cell carcinoma

Estrogen receptors (ERs) are frequently expressed in human tumor tissues. There have been several studies concerning ER expression in esophageal cancers, yet the results are inconsistent, and the prognostic value of the receptors remains unclear. In the present study, we investigated the expression of ER protein and its correlation with clinical features of esophageal squamous cell carcinoma (ESCC) patients. Immunohistochemical staining for the ERs was carried out on paraffin-embedded primary tumor tissue sections from 89 patients with ESCC. Quantitative analyses were performed to determine the prognostic value of the expression of ERs, and Pearson's correlation was used to examine the relationship between ERα and ERβ expression levels. Our results showed that ERα immunoreactivity was significantly lower in ESCC than that in the non-neoplastic epithelium (P=0.0445), whereas the ERβ status was much stronger in ESCC than that in the non-neoplastic epithelium (P=0.0243). A significant inverse correlation was observed between ERα expression and depth of tumor invasion (P=0.0426). Correlation analysis revealed a statistically significant inverse correlation between the expression of ERα and ERβ in ESCC (r=-0.2902, P=0.0058). Kaplan-Meier survival analysis showed that the patients with ERα expression (21/89) had a better outcome than patients without ERα expression (P=0.0280), whereas patients with high ERβ immunoreactivity (44/89) were significantly associated with worse survival (P=0.0366). In conclusion, ERα and ERβ levels were inversely correlated, and the downregulation of ERα and upregulation of ERβ may indicate unfavorable prognosis of ESCC.

Insight into the mechanisms of action of estrogen receptor β in the breast, prostate, colon, and CNS

Estrogen and its receptors (ERs) influence many biological processes in physiology and pathology in men and women. ERs are involved in the etiology and/or progression of cancers of the prostate, breast, uterus, ovary, colon, lung, stomach, and malignancies of the immune system. In estrogen-sensitive malignancies, ERβ usually is a tumor suppressor and ERα is an oncogene. ERβ regulates genes in several key pathways including tumor suppression (p53, PTEN); metabolism (PI3K); survival (Akt); proliferation pathways (p45(Skp2), cMyc, and cyclin E); cell-cycle arresting factors (p21(WAF1), cyclin-dependent kinase inhibitor 1 (CDKN1A)), p27(Kip1), and cyclin-dependent kinases (CDKs); protection from reactive oxygen species, glutathione peroxidase. Because they are activated by small molecules, ERs are excellent targets for pharmaceuticals. ERα antagonists have been used for many years in the treatment of breast cancer and more recently pharmaceutical companies have produced agonists which are very selective for ERα or ERβ. ERβ agonists are being considered for preventing progression of cancer, treatment of anxiety and depression, as anti-inflammatory agents and as agents, which prevent or reduce the severity of neurodegenerative diseases.

Effects of agonists for estrogen receptor α and β on ovariectomy-induced lower urinary tract dysfunction in the rat

The postmenopausal hypoestrogen status induces various lower urinary tract dysfunctions. Ovariectomized (OVX) rats exhibit voiding abnormalities, including increased postvoiding residual urine (PVR), decreased voiding efficiency (VE), and altered coordination between the detrusor and external urethral sphincter (EUS). Estradiol replacement partially normalizes voiding function in OVX rats. We determined if selective agonists for estrogen receptor (ER)α and/or ERβ can reverse lower urinary tract dysfunction in OVX rats. Cystometry and EUS electromyograms (EMGs) were recorded 6 wk after bilateral OVX in urethane-anesthetized female Sprague-Dawley rats. Animals received daily subcutaneous injections of selective ERα [propylpyrazole triol (PPT)] or ERβ [diarylpropionitrile (DPN)] agonists or vehicle for 1 wk starting on the fifth week after OVX. PPT (1 mg·kg(-1)·day(-1)) decreased PVR, improved VE, and shortened the EUS EMG active period (AP) during voiding. DPN (2 or 5 mg·kg(-1)·day(-1)) did not alter cystometric parameters or EUS EMG activity. Combined PPT + DPN treatment elicited changes in PVR, VE, and AP, similar to those induced by PPT alone, but also increased the EUS EMG silent period and volume threshold for triggering micturition. PPT increased uterine weight fourfold and decreased body weight by 11%. DPN increased uterine weight 30-45% but decreased body weight by 3-5%. Reduced voiding efficiency in OVX rats can be reversed by 1-wk drug treatment that selectively targets ERα and reduces AP during EUS bursting. Combined pharmacological activation of ERα and ERβ further enhanced EUS bursting by increasing the EUS EMG silent period and also facilitated bladder storage mechanisms by increasing the volume threshold.

Cadmium mimics estrogen-driven cell proliferation and prolactin secretion from anterior pituitary cells

Cadmium (Cd) is a heavy metal of considerable occupational and environmental concern affecting wildlife and human health. Recent studies indicate that Cd, like other heavy metals, can mimic effects of 17β-estradiol (E2) involving E2 receptor (ER) activation. Lactotrophs, the most abundant cell type in anterior pituitary gland, are the main target of E2, which stimulates cell proliferation and increases prolactin secretion through ERα. The aim of this work was to examine whether Cd at nanomolar concentrations can induce cell proliferation and prolactin release in anterior pituitary cells in culture and whether these effects are mediated through ERs. Here we show that 10 nM Cd was able to stimulate lactotroph proliferation in anterior pituitary cell cultures from female Wistar rats and also in GH3 lactosomatotroph cell line. Proliferation of somatotrophs and gonadotrophs were not affected by Cd exposure. Cd promoted cell cycle progression by increasing cyclins D1, D3 and c-fos expression. Cd enhanced prolactin synthesis and secretion. Cd E2-like effects were blocked by the pure ERs antagonist ICI 182,780 supporting that Cd acts through ERs. Further, both Cd and E2 augmented full-length ERαexpression and its 46 kDa-splicing variant. In addition, when co-incubated Cd was shown to interact with E2 by inducing ERα mRNA expression which indicates an additive effect between them. This study shows for the first time that Cd at nanomolar concentration displays xenoestrogenic activities by inducing cell growth and stimulating prolactin secretion from anterior pituitary cells in an ERs-dependent manner. Cd acting as a potent xenoestrogen can play a key role in the aetiology of different pathologies of the anterior pituitary and in estrogen-responsive tissues which represent considerable risk to human health.

Estrogenic action on innate defense mechanisms in the urinary tract

Clinical data suggest an impact of estrogen on the pathogenesis of urinary tract infections (UTI). In particular, women after menopause often suffer from recurrent UTI, characterized by at least three acute UTI episodes within a year. Aside from bacterial factors promoting persistence within the urinary bladder, the low estrogen levels induce structural and chemical changes in the urogenital tract which facilitate UTI. Increased residual urine volume and changes in the vaginal microflora are well documented risk factors. Local supplementation with estrogen can at least partly reverse these changes. Treatment allows the re-establishment of a lactobacilli-dominated vaginal microflora and improves epithelial differentiation and integrity in the urogenital tract. This estrogenic effect on the epithelium is marked by an increased production of antimicrobial peptides and a tighter intercellular connection, preventing bacteria from reaching cells where they can hide and later emerge and cause a new infection. Estrogen in the dosages and applications used to date is considered safe for the endometrium in the majority of women. Based on the actions and safety of estrogen, local supplementation thus offers a treatment option for postmenopausal women suffering from recurrent UTI.

Implication of androgen receptor in urinary bladder cancer: a critical mini review

Cancer is probably the most dreaded disease of mankind and the bladder cancer is the fifth most common type of cancer worldwide. It is a major cause of cancer morbidity and mortality. From amongst the bladder cancer, the Transitional Cell Carcinoma (TCC) is the most prevalent cancer of the bladder and accounts for 90% of all bladder cancer cases. Despite such a high prevalence, the molecular mechanism involved in the induction of bladder carcinoma and its progression are poorly understood. Tumorigenesis and tumor progression of bladder carcinomas are thought to result from the accumulation of multiple genetic alterations. The Androgen Receptor (AR) gene is located on the q arm of X chromosome (q11-12) and considered as a ligand-inducible transcription factor that regulates target gene expression. The Androgen plays a vital role in the development and maintenance of the normal urinary bladder. The AR is also involved in the development and progression of urinary bladder carcinoma, which is the most common type of carcinoma. Mutation in AR alters the ligand binding ability that may cause the progression and development of bladder cancer. Tumorigenesis and tumor progression are thought to result from changes in the function of hormonal receptor gene. The accumulation of the changes in AR expressions, determines the tumor's phenotype and ultimately the patient's clinical outcome. The early detection of which may help in management and prediction, how will it behave and respond to the therapeutic regimen. The present review aimed to study the mechanism and alteration of AR gene that play a vital role in the tumorIgenesis of bladder carcinoma.

Chemoprevention of BBN-Induced Bladder Carcinogenesis by the Selective Estrogen Receptor Modulator Tamoxifen

Bladder cancer is the fifth most frequent tumor in men and ninth in women in the United States. Due to a high likelihood of recurrence, effective chemoprevention is a significant unmet need. Estrogen receptors (ERs), primarily ERβ, are expressed in normal urothelium and urothelial carcinoma, and blocking ER function with selective ER modulators such as tamoxifen inhibits bladder cancer cell proliferation in vitro. Herein, the chemoprotective potential of tamoxifen was evaluated in female mice exposed to the bladder-specific carcinogen, N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN). Carcinogen treatment resulted in a 76% tumor incidence and increased mean bladder weights in comparison to controls. In contrast, mice receiving tamoxifen concurrent (8-20 weeks) or concurrent and subsequent (8-32 weeks) to BBN administration had no change in bladder weight and only 10% to 14% incidence of tumors. Non-muscle-invasive disease was present in animals treated with tamoxifen before (5-8 weeks) or after (20-32 weeks) BBN exposure, while incidence of muscle-invasive bladder carcinoma was reduced. ERβ was present in all mice and thus is a potential mediator of the tamoxifen chemoprotective effect. Surprisingly, ERα expression, which was detected in 74% of the mice exposed to BBN alone but not in any controlmice, was correlated with tumor incidence, indicating a possible role for this receptor in carcinogen-induced urothelial tumorigenesis. Thus, these data argue that both ERα and ERβ play a role in modulating carcinogen-induced bladder tumorigenesis. Administration of tamoxifen should be tested as a chemopreventive strategy for patients at high risk for bladder cancer recurrence.

Estrogen receptor 1 gene as a tumor suppressor gene in hepatocellular carcinoma detected by triple-combination array analysis

Hepatocellular carcinoma (HCC) is one of the top five causes of cancer-related deaths worldwide. Recent developments in the treatment of HCC remain insufficient to cure unresectable disease or to prevent HCC. Consistent efforts are, therefore, needed to deepen understanding of pathogenesis of the disease. Genome-wide gene expression profile analyses can now detect various candidate genes that are modified by HCC. We have developed a new technique to identify tumor suppressor genes, triple-combination array analysis, which combines gene expression profiles, single nucleotide polymorphism and methylation arrays to identify genes with altered expression. Using HCC tissue samples, triple-combination array analysis was performed to identify a candidate tumor suppressor gene. Subsequently, samples from 48 HCC patients were subjected to quantitative polymerase chain reaction (qPCR) and methylation-specific PCR to further elucidate clinical relevance of the gene. Estrogen receptor 1 (ESR1) was detected as a candidate tumor suppressor gene. Of the 48 clinical samples, 40 (83.3%) showed ESR1 promoter hypermethylation. In 24 (50%) HCC samples, the expression levels of the ESR1 gene was decreased by >90%. The decreased expression was significantly related to high liver damage score, pathological invasion of the intrahepatic portal vein, the size of tumor (>3 cm in diameter) and hepatitis B virus infection. The present study represents another example that triple-combination array is a convenient technique for detecting genes with altered expression in disease. The ESR1 gene was identified as a candidate tumor suppressor gene in HCC and further validation is warranted.

Estrogen receptor-β expression and pharmacological targeting in bladder cancer

A role for estrogen signaling in urothelial carcinoma of the bladder (UCB) is suggested to be associated with more advanced disease with worse outcomes in women. Estrogen receptor β (ERβ) is the predominant receptor in bladder tissues. We aimed to ascertain whether ERβ correlates with clinicopathological predictors of aggressive bladder cancer and worse survival outcomes. ERβ was measured by immunohistochemistry in malignant and adjacent benign bladder tissues in patients (N=72) with UCB who underwent radical cystectomy. ERβ expression was tested for statistical association with clinicopathological variables and patient survival. ERβ expression was determined in bladder cancer cell lines, and the effects of the selective estrogen modulator tamoxifen and the ERβ agonist diarylpropionitrile on cell growth were determined. The ERβ level was significantly higher in malignant vs. benign urothelium (P<0.001) and was strongly associated with aggressive tumor histology characterized by lymphovascular (P=0.008) and perineural (P=0.006) invasion, and clinical histories of pelvic irradiation (P=0.005), hydronephrosis (P=0.022) and no intravesical chemotherapy (P=0.038). All patients with a high (>70%) percentage of ERβ positivity in tissue with >3-month follow-up developed recurrent disease (P=0.009). Higher ERβ level was predictive of worse recurrence-free and overall survival following cystectomy, after adjustment for tumor stage, and remained significantly associated with recurrence-free survival in the multivariable analysis including tumor stage, nodal stage and lymphovascular invasion. Activation of ERβ in bladder cancer cell lines led to significant increases in proliferation, while pharmacological inhibition with tamoxifen blocked cell growth. Our study supports a role for ERβ in aggressive UCB. Pharmacological targeting of ERβ warrants further investigation as a therapeutic strategy in UCB.

Role of oestrogen receptors in bladder cancer development

Early studies documented the existence of sexual dimorphism in bladder cancer occurrence and progression, with a greater bladder cancer incidence in males than females. However, the progression of bladder cancer after diagnosis is much quicker in females than males. These findings can be explained by the effects of female hormones (predominantly oestrogens) and their binding receptors, including oestrogen receptor 1 (ESR1; also known as ERα), oestrogen receptor 2 (ESR2; also known as ERβ), and GPR30 protein on bladder cancer incidence and progression. Results from studies using various in vitro cell lines and in vivo mouse models demonstrate differential roles of oestrogen receptors in cancer initiation and progression. ERα suppresses bladder cancer initiation and invasion, whereas ERβ promotes bladder cancer initiation and progression. Mechanistic studies suggest that ERα and ERβ exert these effects via modulation of the AKT pathway and DNA replication complex, respectively. Targeting these signalling pathways--for example, with ERα agonists, ERβ antagonists, or selective oestrogen receptor modulators such as 4-[2-phenyl-5,7-bis(trifluoromethyl)pyrazolo[1,5-a]pyrimidin-3-yl]phenol (also known as PHTPP)--could lead to the development of new therapeutic approaches for controlling bladder cancer progression.

Urothelial signaling

The urothelium, which lines the inner surface of the renal pelvis, the ureters, and the urinary bladder, not only forms a high-resistance barrier to ion, solute and water flux, and pathogens, but also functions as an integral part of a sensory web which receives, amplifies, and transmits information about its external milieu. Urothelial cells have the ability to sense changes in their extracellular environment, and respond to chemical, mechanical and thermal stimuli by releasing various factors such as ATP, nitric oxide, and acetylcholine. They express a variety of receptors and ion channels, including P2X3 purinergic receptors, nicotinic and muscarinic receptors, and TRP channels, which all have been implicated in urothelial-neuronal interactions, and involved in signals that via components in the underlying lamina propria, such as interstitial cells, can be amplified and conveyed to nerves, detrusor muscle cells, and ultimately the central nervous system. The specialized anatomy of the urothelium and underlying structures, and the possible communication mechanisms from urothelial cells to various cell types within the bladder wall are described. Changes in the urothelium/lamina propria ("mucosa") produced by different bladder disorders are discussed, as well as the mucosa as a target for therapeutic interventions.

Raloxifene inhibits growth of RT4 urothelial carcinoma cells via estrogen receptor-dependent induction of apoptosis and inhibition of proliferation

Bladder cancer is the fifth most common type of cancer in the USA, with over 70,000 new cases diagnosed each year. Treatment often involves invasive surgical therapies, as chemotherapy alone is often ineffective and associated with high recurrence rates. Identification of estrogen receptor-β (ERβ) in up to 75 % of urinary tumors raises the question of whether this receptor could be targeted to effectively treat bladder cancer. In this study, a panel of five bladder cancer cell lines representing a variety of disease stage and grades were treated with the antiestrogens 4-hydroxytamoxifen, raloxifene, or the pure antagonist ICI 182,780. All cell lines were ERβ positive while only a few expressed estrogen receptor-α (ERα). Notably, all but the TCCSUP cell line were growth inhibited 20-100 % by at least two antiestrogens. Using RT4 cells, we demonstrate that growth inhibition by raloxifene is ER dependent and either ERα or ERβ can mediate this response. Activation of caspase-3 and its effector poly-ADP ribose polymerase (PARP) demonstrate that raloxifene-induced growth inhibition is in part the result of increased apoptosis; this PARP cleavage was ER dependent. Moreover, changes in the expression of cell cycle genes indicate that cell proliferation is also affected. Specifically, raloxifene treatment results in the stabilization of p27 protein, likely via the downregulation of S-phase kinase-associated protein (SKP2). Expression of the negative cell cycle regulator B-cell translocation gene (BTG2) is also increased, while cyclin D1 transcription is reduced. These results indicate that antiestrogens may be useful therapeutics in the treatment of bladder cancer by targeting ER and inhibiting growth via multiple mechanisms.

Cell proliferation and apoptosis in urinary bladder urothelium of rats following ovariectomy and chronic estrogen replacement therapy

AIMS

In this study we followed the effect of menopause and estrogenic replacement therapy on the proliferative and apoptotic activity of the bladder urothelial cells.

METHODS

The experimental model of menopause was reproduced using a standard protocol of bilateral ovariectomy in rats, estrogen replacement therapy being achieved by systemic administration of hexestrol diacetate for six weeks. Proliferative and apoptotic activity was monitored by quantifying the urothelium imunoexpression for PCNA antigen as a marker of S phase of the cell cycle and Cleaved Caspase 3 for monitoring apoptotic activity.

RESULTS

Following ovariectomy, the main changes were urothelial atrophy associated with intensification of the apoptotic activity at these level. Estrogen therapy managed to improve the urothelium activity by reducing the Apoptotic Index and by increasing urothelial proliferative activity.

CONCLUSIONS

The results show the important role of estrogens in maintaining urothelial activities, highlighting their potential use in the treatment of urothelium atrophic and degenerative processes associated with menopause.

Expression of UDP-glucuronosyltransferase 1A in bladder cancer: association with prognosis and regulation by estrogen

Although UDP-glucuronosyltransferase 1A (UGT1A) plays an important role in preventing bladder cancer initiation by detoxifying carcinogenic compounds, its contribution to bladder cancer progression is poorly understood. We immunohistochemically stained for UGT1A in bladder specimens. UGT1A was positive in 130/145 (90%; 28 [19%] weak, 53 [37%] moderate, and 49 [34%] strong) urothelial neoplasms, which was significantly weaker than in matched non-neoplastic urothelial tissues (100/101 [99%]; 2 [2%] weak, 17 [17%] moderate, and 81 [80%] strong). Fifty (98%) of 51 low-grade/79 (99%) of 80 non-muscle-invasive tumors were immunoreactive to UGT1A, whereas 80 (85%) of 94 high-grade/51 (78%) of 65 muscle-invasive tumors were UGT1A-positive. Kaplan-Meier analysis showed strong associations between lower UGT1A expression versus the risk of recurrence in high-grade non-muscle-invasive tumors (P = 0.038) or disease-specific mortality in muscle-invasive tumors (P = 0.016). Multivariate analysis further revealed UGT1A loss as an independent prognosticator for disease-specific mortality in patients with muscle-invasive tumor (P = 0.010). Additionally, the expression of UGT1A was positively and negatively correlated with those of estrogen receptor-α and estrogen receptor-β, respectively. We then assessed UGT1A/Ugt1a levels in human cell lines/mouse tissues. 17β-Estradiol increased and decreased UGT1A expression in normal urothelium and bladder cancer lines, respectively, and an anti-estrogen abolished these effects. Ovariectomy in mice resulted in down-regulation of Ugt1a subtypes. These results suggest the involvement of UGT1A in not only bladder carcinogenesis but tumor progression. Moreover, UGT1A is likely regulated by estrogens in non-neoplastic urothelium versus bladder tumor in opposite manners, which could be underlying mechanisms of gender-specific differences in bladder cancer incidence and progression.

Epidermal growth factor induces bladder cancer cell proliferation through activation of the androgen receptor

Androgen receptor (AR) signals have been suggested to contribute to bladder tumorigenesis and cancer progression. Activation of epidermal growth factor receptor (EGFR) also leads to stimulation of bladder tumor growth. However, crosstalk between AR and EGFR pathways in bladder cancer remains uncharacterized. We have recently shown that androgens activate the EGFR pathway in bladder cancer cells. The purpose of this study was to investigate the effects of EGF on AR activity in bladder cancer. EGF increased AR transcriptional activity by 1.2-, 1.9- and 2.0-fold in UMUC3, 5637-AR and J82-AR cell lines, respectively, over mock treatment and a specific EGFR inhibitor, PD168393, antagonized the EGF effect. Combined treatment of EGF and dihydrotestosterone (DHT) further induced AR transactivation while an AR antagonist, hydroxyflutamide (HF), abolished the effect of not only DHT but also EGF. In growth assays, EGF alone/DHT alone/EGF+DHT increased cell numbers by 16/12/19%, 6/14/18% and 30/12/38% in UMUC3-control-shRNA, 5637-AR and J82-AR, respectively, whereas the effects of EGF were marginal or less significant in UMUC3-AR-shRNA (8%) or AR-negative 5637-V (<1%) and J82-V (17%) cells. HF treatment at least partially counteracted the EGF effect on the growth of AR-positive cells. Western blotting demonstrated that EGF, especially in the presence of DHT, upregulated the expression of the p160 coactivator TIF2 and HF again blocked this stimulation. Co-immunoprecipitation revealed the association between AR and estrogen receptor (ER)-β or Src in UMUC3 cells and stronger associations with EGF treatment, implying the involvement of the AR/ER/Src complex in EGF-increased AR transactivation and cell growth. Current results, thus, suggest that EGF promotes bladder cancer cell proliferation via modulation of AR signals. Taken together with our previous findings, crosstalk between EGFR and AR pathways can play an important role in the progression of bladder cancer.

Receptor-targeted therapy of human experimental urinary bladder cancers with cytotoxic LH-RH analog AN-152 [AEZS- 108]

Many bladder cancers progress to invasion with poor prognosis; new therapeutic methods are needed. We developed a cytotoxic LH-RH analog, AN-152 (AEZS-108) containing doxorubicin (DOX), for targeted therapy of cancers expressing LHRH receptors. We investigated the expression of LH-RH receptors in clinical bladder cancers and in HT-1376, J82, RT-4 and HT-1197 human bladder cancer lines. The effect of analog, AN-152, on growth of these tumor lines xenografted into nude mice was analyzed. Using molecular and functional assays, we also evaluated the differences between the effects of AN-152, and DOX alone. We demonstrated the expression of LH-RH receptors on 18 clinical bladder cancers by immunohistochemistry and on four human urinary bladder cancer lines HT-1376, J82, RT-4 and HT-1197 by Western blotting and binding assays. AN-152 powerfully inhibited growth of these bladder cancers in nude mice. AN-152 exerted greater effects than DOX and was less toxic. DOX activated strong multidrug resistance mechanisms in RT-4 and HT-1197 cancers, while AN-152 had no or less such effect. PCR assays and in vitro studies revealed differences in the action of AN-152 and DOX on the expression of genes involved in apoptosis. These results suggest that targeted cytotoxic LH-RH analog, AN-152 (AEZS- 108), should be examined for treatment of patients with LH-RH receptor positive invasive bladder cancers.

GATA binding protein 3 is down-regulated in bladder cancer yet strong expression is an independent predictor of poor prognosis in invasive tumor

Although GATA binding protein 3, a zinc finger transcription factor and an estrogen receptor-regulated gene, has recently been suggested as a marker for urothelium, prognostic significance of GATA binding protein 3 expression in bladder tumor remains unclear. We immunohistochemically stained for GATA binding protein 3 in urothelial neoplasm and matched nonneoplastic bladder tissue specimens. GATA binding protein 3 was positive in 125 (86%; 13 [9%] weak, 44 [30%] moderate, and 68 [47%] strong) of 145 bladder tumors, which was significantly lower than in benign urothelium (104/106 [98%]; 3 [3%] weak, 30 [28%] moderate, and 71 [67%] strong) (P=.001). Fifty (98%) of 51 low-grade tumors were GATA binding protein 3 positive, whereas 75 (80%) of 94 high-grade carcinomas were GATA binding protein 3 positive (P=.002). Similarly, 78 (98%) of 80 non-muscle-invasive tumors expressed the GATA binding protein 3, compared with 47 (72%) of 65 muscle-invasive tumors (P<.001). Conversely, among 68 cases treated with cystectomy, significantly lower expression of GATA binding protein 3 was found in pN0 tumors (32/47 [68%]) than in node-positive tumors (20/21 [95%]) (P=.027). Kaplan-Meier and log-rank tests further revealed that overall positivity (P=.048) or strong positivity (P=.025) of GATA binding protein 3 correlated with progression of muscle-invasive tumors. Multivariate analysis identified high GATA binding protein 3 expression as a strong prognosticator for progression (P=.052) and cancer-specific survival (P=.040) of muscle-invasive tumors. Moreover, there were significant correlations between GATA binding protein 3 expression vs androgen receptor overexpression, estrogen receptor α overexpression, or loss of estrogen receptor β expression. Thus, compared with benign urothelium, a significant decrease in the expression of GATA binding protein 3 in urothelial neoplasms was seen. Loss of GATA binding protein 3 was associated with high-grade and/or muscle-invasive tumors, whereas strong expression was an independent predictor of poor prognosis.

Estrogen receptor α and β in esophageal squamous cell carcinoma

A gender difference has been reported in the morbidity of esophageal squamous cell carcinoma (ESCC). Estrogens have been proposed to play a role in this difference but the details have not yet been clarified. Therefore, in the present study, we examined the status of estrogen receptor (ER)α and ERβ in 90 Japanese ESCC patients. ERα and ERβ immunoreactivity was detected in the nuclei of ESCC cells (41.1 and 97.8%, respectively). There was a significant positive association between the ERβ H score and histological differentiation (P = 0.0403), TNM-pM (LYM) (P = 0.00164) and Ki67/MIB1 LI of carcinoma cells (P = 0.0497, r = 0.207). In addition, the ERβ status of carcinoma cells was significantly correlated with unfavorable clinical outcome of the patients. Multivariate analysis further revealed the ERβ status in carcinoma cells as an independent unfavorable prognostic factor of these patients. We further examined the effects of estrogen treatment on ESCC cell line (ECGI-10) transfected with ERα or ERβ in vitro. The number of ECGI-10 transfected with ERβ was increased by estradiol or ERβ specific agonist but estradiol did not exert any effect upon the cell number of ECGI-10 transfected with ERα. In summary, the results of the present study clearly demonstrate that the status of ERβ in ESCC was closely associated with the unfavorable prognosis, possibly through altering cell proliferation of carcinoma cells.

Estrogen receptor β (ERβ) is a novel prognostic marker of recurrence survival in non-muscle-invasive bladder cancer potentially by inhibiting cadherin switch

OBJECTIVE

The function and significance of estrogen receptor β (ERβ) in bladder cancer remains a field of hot debate. In this study, we aimed to (a) evaluate ERβ as a novel prognostic marker of recurrence-free survival and (b) digest the underlying mechanism by elucidating the relationship between ERβ expression and cadherin switch.

METHODS

We examined the expression levels of ERβ, E-cadherin and N-cadherin in 42 initial non-muscle-invasive urothelial bladder carcinomas via immunohistochemistry. Correlation analysis was performed among ERβ expression, cadherin switch, and recurrence-free survival. Moreover, in vitro studies were performed to validate the identified correlation using two bladder cancer cell lines RT4 and 253 J. Upon stimulation with an ERβ-selective agonist diarylpropionitrile, E-cadherin, N-cadherin expressions; cell migration, and invasion capacity were assessed.

RESULTS

Expression of ERβ protein was seen in 34 bladder cancer cases (80.9%), and 21 (50%) specimens showed non-cadherin switch (positive E-cadherin and negative N-cadherin). ERβ expression and the non-cadherin switch are both accompanied with better recurrence-free survival. Also, the least ERβ expression was observed in specimens that undergo cadherin switch. Moreover, these results were consistent with our observations in bladder cancer RT4 and 253 J cell lines studies. Diarylpropionitrile stimulation resulted in an increase in E-cadherin, a decrease in N-cadherin expressions and abolished cell migration and invasion.

CONCLUSION

ERβ is a prognostic marker of recurrence-free rate in non-muscle-invasive bladder cancer, potentially through suppressing cadherin switch, and may act as a potential target for bladder cancer therapy.

Expression of androgen and oestrogen receptors and its prognostic significance in urothelial neoplasm of the urinary bladder

What's known on the subject? and What does the study add? Steroid hormone receptor signals have been implicated in bladder tumourigenesis and tumour progression. The expression of androgen and/or oestrogen receptors has been assessed in bladder cancer, leading to conflicting data of expression levels and their relationship to histopathological characteristics of the tumours. We simultaneously analyze three receptors in non-neoplastic bladder tissues as well as in primary and metastatic bladder tumour specimens. Our data demonstrate that the expression status correlates with tumour grades/stages and patients' outcomes.

OBJECTIVE

To assess the expression of the androgen receptor (AR) and oestrogen receptors (ERs) in bladder tumours because recent studies have shown conflicting results and the prognostic significance of their expression remains unclear.

PATIENTS AND METHODS

We investigated the expression of AR, ERα and ERβ in 188 bladder tumour specimens, as well as matched 141 non-neoplastic bladder and 14 lymph node metastasis tissues, by immunohistochemistry. We then evaluated the relationships between their expression and the clinicopathological features available for the present patient cohort.

RESULTS

AR/ERα/ERβ was positive in 80%/50%/89% of benign urothelium, 50%/67%/41% of benign stroma, 42%/27%/49% of primary tumours and 71%/64%/71% of metastatic tumours. Significantly lower expression of AR/ERα was found in high-grade tumours (36%/23%) and tumours invading muscularis propria (33%/19%) compared to low-grade tumours (55%; P= 0.0232/38%; P= 0.0483) and tumours not invading muscularis propria (51%; P= 0.0181/35%; P= 0.0139), respectively. Significantly higher expression of ERβ was found in high-grade tumours (58%) and tumours invading muscularis propria (67%) compared to low-grade tumours (29%; P= 0.0002) and tumours not invading muscularis propria (34%; P < 0.0001), respectively. Kaplan-Meier and log-rank tests further showed that positivity of ERβ (but not AR or ERα) was associated with the recurrence of low-grade tumours (P= 0.0072); the progression of low-grade tumours (P= 0.0005), high-grade tumours not invading muscularis propria (P= 0.0020) and tumours invading muscularis propria (P= 0.0010); or disease-specific mortality in patients with tumours invading muscularis propria (P= 0.0073).

CONCLUSIONS

Compared to benign bladders, a significant decrease in the expression of AR, ERα or ERβ in bladder cancer was seen. Loss of AR or ERα was strongly associated with higher grade/more invasive tumours, whereas ERβ expression was increased in high-grade/invasive tumours and predicted a worse prognosis.

Epidermal growth factor receptor expression in urinary bladder cancer

Objective:

To evaluate the expression pattern of epidermal growth factor receptor (EGFR) in urinary bladder cancer and its association with human epidermal growth factor receptor 2 (HER2), epidermal growth factor (EGF), interleukin-6 (IL-6), and high risk human papilloma virus (HPV) types 16 and 18.

Materials and Methods:

Thirty cases of urothelial carcinoma were analyzed. EGFR, HER2, EGF, and IL-6 expressions in the tissue were evaluated by immunohistochemical staining. For HPV, DNA from tissue samples was extracted and detection of HPV was done by PCR technique. Furthermore, evaluation of different intracellular molecules associated with EGFR signaling pathways was performed by the western blot method using lysates from various cells and tissues.

Results:

In this study, the frequencies of immunopositivity for EGFR, HER2, EGF, and IL-6 were 23%, 60%, 47%, and 80%, respectively. No cases were positive for HPV-18, whereas HPV-16 was detected in 10% cases. Overall, expression of EGFR did not show any statistically significant association with the studied parameters. However, among male patients, a significant association was found only between EGFR and HER2.

Conclusions:

Overexpression of EGFR and/or HER2, two important members of the same family of growth factor receptors, was observed in a considerable proportion of cases. Precise knowledge in this subject would be helpful to formulate a rational treatment strategy in patients with urinary bladder cancer.

Interaction between ionizing radiation and estrogen: what we are missing?

Following complexity as a new approach in science of 21st century biomonitoring of biological effects caused by ionizing radiation received an option of a new dimension. Insight in biological response of mammals to ionizing radiation exposure by integration of genome, non-genome and distant organ bystander effects will significantly change evaluation of health risk and preventive measures. Impact of estrogen on carcinogenesis caused by occupational or accidental exposure to ionizing radiation additionally enables biodosimetry to recognize vulnerable subpopulations according to gender and age. Estrogen, as a potent molecule involved in number of biological pathways during development and adulthood, shows close interaction with pathological processes launched by overexposure to ionizing radiation which should be included in future research and radiation protection.

Molecular mechanisms of bladder outlet obstruction in transgenic male mice overexpressing aromatase (Cyp19a1)

We investigated the etiology and molecular mechanisms of bladder outlet obstruction (BOO). Transgenic (Tg) male mice overexpressing aromatase (Cyp19a1) under the ubiquitin C promoter in the estrogen-susceptible C57Bl/6J genetic background (AROM+/6J) developed inguinal hernia by 2 months and severe BOO by 9 to 10 months, with 100% penetrance. These mice gradually developed uremia, renal failure, renal retention, and finally died. The BOO bladders were threefold larger than in age-matched wild-type (WT) males and were filled with urine on necropsy. Hypotrophic smooth muscle cells formed the thin detrusor urinae muscle, and collagen III accumulation contributed to the reduced compliance of the bladder. p-AKT and ERα expression were up-regulated and Pten expression was down-regulated in the BOO bladder urothelium. Expression of only ERα in the intradetrusor fibroblasts suggests a specific role of this estrogen receptor form in urothelial proliferation. Inactivation of Pten, which in turn activated the p-AKT pathway, was strictly related to the activation of the ERα pathway in the BOO bladders. Human relevance for these findings was provided by increased expression of p-AKT, PCNA, and ERα and decreased expression of PTEN in severe human BOO samples, compared with subnormal to mild samples. These findings clarify the involvement of estrogen excess and/or imbalance of the androgen/estrogen ratio in the molecular pathogenetic mechanisms of BOO and provide a novel lead into potential treatment strategies for BOO.

Lower risk in parous women suggests that hormonal factors are important in bladder cancer etiology

BACKGROUND

Urinary bladder cancer is two to four times more common among men than among women, a difference in risk not fully explained by established risk factors. Our objective was to determine whether hormonal and reproductive factors are involved in female bladder cancer.

METHODS

We analyzed data from two population-based studies: the Los Angeles-Shanghai Bladder Cancer Study, with 349 female case-control pairs enrolled in Los Angeles and 131 female cases and 138 frequency-matched controls enrolled in Shanghai, and the California Teachers Study (CTS), a cohort of 120,857 women with 196 incident cases of bladder urothelial carcinoma diagnosed between 1995 and 2005. We also conducted a meta-analysis summarizing associations from our primary analyses together with published results.

RESULTS

In primary data analyses, parous women experienced at least 30% reduced risk of developing bladder cancer compared with nulliparous women (Shanghai: OR = 0.38, 95% CI: 0.13-1.10; CTS: RR = 0.69, 95% CI: 0.50-0.95) consistent with results of a meta-analysis of nine studies (summary RR = 0.73, 95% CI: 0.63-0.85). The CTS, which queried formulation of menopausal hormone therapy (HT), revealed a protective effect for use of combined estrogen and progestin compared with no HT (RR = 0.60, 95% CI: 0.37-0.98). Meta-analysis of three studies provided a similar effect estimate (summary RR = 0.65, 95% CI: 0.48-0.88).

CONCLUSIONS

A consistent pattern of reduced bladder cancer risk was found among parous women and those who used estrogen and progestin for HT.

IMPACT

These results suggest that more research is warranted to investigate hormonal and reproductive factors as possible contributors to bladder cancer risk.

Personalized therapy for urothelial cancer: review of the clinical evidence

Despite a detailed understanding of the molecular aberrations driving the development of urothelial cancers, this knowledge has not translated into advances for the treatment of this disease. Urothelial cancers are chemosensitive, and platinum-based combination chemotherapy remains the standard of care for advanced disease, as well as neoadjuvant and adjuvant therapy for locally advanced disease. However, nearly half of patients who undergo resection of locally advanced urothelial cancer will relapse and eventually develop platinum-resistant disease. Clinical trials of targeted agents against angiogenesis and growth factors, as well as novel chemotheraputics, have generally been unsuccessful in urothelial cancers. Improvements in the theraputic arsenal for urothelial cancer depend upon identification of new targets and strategies to overcome platinum resistance.

Urothelial signaling

The urinary bladder "mucosa" or innermost portion of the bladder is composed of transitional epithelium, basement membrane, and the lamina propria. This chapter reviews the specialized anatomy of the bladder epithelium (urothelium) and speculates on possible communication mechanisms from urothelial cells to various cell types within the bladder wall. For example, beyond serving as a simple barrier, there is growing evidence that the urinary bladder urothelium exhibits specialized sensory properties and plays a key role in the detection and transmission of both physiological and nociceptive stimuli. Findings from a number of studies suggest that the urothelium exhibits both "sensor" (expressing receptors/ion channels capable of responding to thermal, mechanical, and chemical stimuli) and "transducer" (ability to release chemicals) properties. Thus, urothelial cells exhibit the ability to sense changes in their extracellular environment including the ability to respond to chemical, mechanical, and thermal stimuli that may communicate the state of the urothelial environment to the underlying nervous and muscular systems.

Clinical characteristics of bladder urothelial tumors in male patients--the influences of benign prostatic hyperplasia/benign prostatic enlargement

OBJECTIVES

To investigate the clinical characteristics of bladder urothelial tumors in male patients.

PATIENTS AND METHODS

The clinical characteristics of 356 patients with newly diagnosed bladder urothelial tumors from July 2005 to January 2010 were analyzed. Characteristics of different age groups were compared. Furthermore, tumor characteristics were analyzed to define the relationship, if any, with benign prostatic hyperplasia/benign prostatic enlargement.

RESULTS

For bladder urothelial tumors, the percentage of carcinoma increased significantly with increasing age (P < 0.001), and differences were found among 3 age groups in the distribution of high grade carcinoma (P = 0.012). Especially in non-muscle-invasive carcinoma, the percentage of high grade carcinoma increased significantly with increasing age (P = 0.006), with significant differences between the ≤50 years group and the 51-69 years group and ≥70 years group (P = 0.031, P = 0.002). Interestingly, compared with non-benign prostatic hyperplasia/benign prostatic enlargement patients, benign prostatic hyperplasia/benign prostatic enlargement patients were more frequently diagnosed with poorly differentiated tumors, and logistic regression confirmed associations between benign prostatic hyperplasia/benign prostatic enlargement and unfavorable carcinoma, controlling for age (P = 0.009).

CONCLUSIONS

Age is an unfavorable influence on the clinical characteristics of bladder urothelial tumors in men, and it was observed that the percentage of unfavorable tumors increased with age. Interestingly, noticeable changes of tumor differentiation appeared at the age of 50 years, and it was indicated that the natural history of carcinoma appeared to differ according to benign prostatic hyperplasia/benign prostatic enlargement statuses. There was a tendency for the men, who were diagnosed with benign prostatic hyperplasia/benign prostatic enlargement, to present with unfavorable carcinoma.

Anti-tumour efficacy of mitofusin-2 in urinary bladder carcinoma

Mitochondrial GTPase mitofusin-2 gene (Mfn2) is a novel gene characterised as a cell proliferation inhibitor. Mfn2 protein over-expression, mediated by an adenovirus, has a significant anti-tumour effect in A548 and HT-29 cells. However, there is no report on the effect of Mfn2 on urinary bladder carcinoma (UBCC). In this study, we sought to investigate the function of Mfn2 in UBCC. Mfn2 expression in 36 paired UBCC samples was investigated by reverse transcription-polymerase chain reaction and Western blot analyses. An adenovirus encoding the complete Mfn2 open reading frame (Ad-Mfn2) was used to infect UBCC cells, and an adenoviral vector encoding green fluorescent protein (Ad-GFP) was used as a control. The effects of Mfn2 on cell-cycle distribution and apoptosis were assessed by flow cytometry and Western blot analyses. The Mfn2 protein showed significantly lower expression in UBCC tissues than nearby non-tumourous tissues. Ad-Mfn2 exhibited a significant anti-tumour effect in T24 and 5,637 cells. Mfn2 overexpression in T24 cells significantly inhibited cell proliferation, by arresting the transition of the cell cycle from the G(1) to S phase, and induced apoptosis by upregulating active caspase-3 and cleaved PARP levels. Mfn2 also induced increased p21 and p27 expression levels, but down-regulated PCNA levels. These findings indicate that Mfn2 is a potential UBCC tumour suppressor gene, which showed significantly lower expression in tumour tissues than adjacent non-tumourous tissues and could promote apoptosis and inhibit the proliferation of UBCC cells. Mfn2 may become an important therapeutic target for treating UBCC.

Estrogen receptor alpha polymorphisms and the risk of malignancies

Estrogens represent risk factors for endocrine-related cancers and play also an important role in the development and progression of other malignancies. In order to analyze the associations between estrogen receptor gene alpha polymorphisms and cancers susceptibility, we genotyped six single nucleotide polymorphisms (SNPs) in 163 Caucasian cancer patients--103 breast cancers and 60 other malignancies (colorectal, bladder, hepatocellular carcinoma and acute myeloid leukemia)--and 114 healthy controls using hybridization probes. We performed Armitage`s association trend-test to evaluate the risk. Linkage disequilibrium (LD) was assessed for each pair of markers. The genotypes CC and CT of rs3798577 were significantly associated with the cancers risk (p-trend breast = 4 × 10(-5); p-trend cancers = 1 × 10(-5)); in discrepancy with breast cancer where the C-allele represented the risk allele, for bladder, hepatocellular carcinomas and leukemia, the T allele seems to confer susceptibility. The minor G allele of rs1801132 was protective in our cases (p = 1 × 10(-4)); for rs2228480, the heterozygous frequency was higher for cancer groups (p = 0.03); the SNP pairs rs2228480&rs3798577 and rs2234693&rs9340799 were in low LD; the haplotypes T-A of rs2234693&rs9340799 and G-C of rs2228480&rs3798577 showed a trend to be higher represented in breast cancers; T allele of rs2234693 was higher expressed in breast, colon cancers and leukemia; rs2077647 was associated with colon (p = 0.008, C-risk allele) and bladder (p = 0.01, T-risk allele) cancers. We concluded that ESR1 polymorphisms may have distinct impact in carcinogenesis and further genotyping will establish whether these findings remain significant in larger cohorts.

Potential health-modulating effects of isoflavones and metabolites via activation of PPAR and AhR

Isoflavones have multiple actions on cell functions. The most prominent one is the activation of estrogen receptors. Other functions are often overlooked, but are equally important and explain the beneficial health effects of isoflavones. Isoflavones are potent dual PPARα/γ agonists and exert anti-inflammatory activity, which may contribute to the prevention of metabolic syndrome, atherosclerosis and various other inflammatory diseases. Some isoflavones are potent aryl hydrocarbon receptor (AhR) agonists and induce cell cycle arrest, chemoprevention and modulate xenobiotic metabolism. This review discusses effects mediated by the activation of AhR and PPARs and casts a light on the concerted action of isoflavones.

Androgen receptor is a potential therapeutic target for bladder cancer

OBJECTIVES

To investigate whether androgen receptor (AR) could serve as a potential molecular target for the treatment of bladder cancer.

METHODS

Cell proliferation, apoptosis, and migration capacity were determined in human transitional carcinoma cell lines T24 and 253-J treated with small interfering RNA directed against AR, and expression levels of growth- and metastasis-related genes were assessed using quantitative reverse transcriptase-polymerase chain reaction. Tumor cell growth and apoptosis were also evaluated in vivo in T24 tumor-bearing nude mice receiving electroporation-assisted administration of anti-AR small interfering RNA.

RESULTS

AR expression knockdown produced increased apoptosis, decreased proliferation, and migration of bladder cancer cells. Cyclin D1, Bcl-x(L), and matrix metallopeptidase-9 gene expression were also reduced with AR knockdown, which might have contributed to the altered biological behavior of cancer cells. In vivo experiments showed that silencing AR expression, by interference aided by electroporation, significantly suppressed AR-positive bladder tumor growth with decreased cell proliferation and increased apoptotic rates.

CONCLUSIONS

Downregulation of AR expression inhibits bladder cancer cell growth in vitro and in vivo, implying that its use might be a potential therapeutic target for the treatment of bladder cancer.

Clinical and molecular features of differentiated thyroid cancer diagnosed during pregnancy

OBJECTIVE

Pregnancy represents a favorable condition for the development of thyroid nodules, likely due to the secretion of hormones with stimulatory activity. In particular, differentiated thyroid cancer (DTC) represents the second most frequent tumor among those diagnosed during pregnancy. However, few and discordant data are available about the impact of pregnancy on tumor outcome.

METHODS

A total of 123 women with DTC were divided into three groups according to the timing of tumor diagnosis (group 1, at least 1 year after the delivery; group 2, during pregnancy or in the first year after delivery; and group 3, before pregnancy or nulliparity) and evaluated according to the international guidelines. Furthermore, immunohistochemical studies of estrogen receptor alpha (ERalpha) were performed in 38 papillary thyroid cancer tissues from the three groups.

RESULTS

Thyroid cancer diagnosed during pregnancy was associated with a poorer prognosis compared to tumors developed in nongravidic periods (P<0.0001). Accordingly, at the stepwise logistic regression analysis, the diagnosis of DTC during pregnancy or in the first year post partum was the most significant indicator of persistent disease (P=0.001). Interestingly, ERalpha expression significantly differed among tumors of the three groups, being detected in 31% of group 1, in 87.5% of group 2, and in 0% of group 3 (P=0.01).

CONCLUSIONS

Present data indicate that pregnancy has a negative impact on the outcome of thyroid cancer. The presence of ERalpha in the majority of tumors diagnosed during pregnancy indicates that the poorer outcome of these cases could be related to the estrogen-mediated growth stimulus.

Integrated genomic and transcriptional analysis of the in vitro evolution of telomerase-immortalized urothelial cells (TERT-NHUC)

Much progress has been made in identifying the molecular genetic alterations that occur in bladder cancer. However, in many cases the genes targeted by these alterations are not known. Telomerase immortalized human urothelial cells (TERT-NHUC) are a useful resource for in vitro studies of genes involved in urothelial transformation. When cultured under standard conditions they remain genetically stable but when cultured under low-density conditions they exhibit genetic instability and acquire chromosomal alterations. TERT-NHUC from three donors were cultured at low plating density and examined at four time-points during a culture period of 600 days. Analyses included population doubling kinetics, array-based CGH (aCGH), chromosome counts, fluorescence in situ hybridization (FISH), mutation analysis, Affymetrix gene expression analysis, Western blotting for p16, anchorage-independent growth and tumorigenicity assays. Alterations acquired during continued culture of TERT-NHUC at low density (TERT-NHUC-L) included some observed in urothelial carcinoma (UC) cell lines and primary UC. Examination of gene expression in TERT-NHUC with distinct acquired genetic aberrations may pinpoint genes targeted by these alterations. Data from an aCGH study of UC cell lines and primary tumors were examined for changes in chromosomal regions that also showed alterations in TERT-NHUC-L. Loss of a region on 2q including BOK was identified in UC cell lines and primary tumors. DNER and FRAS1 were identified as potential candidate genes, whose expression is altered independently of the acquisition of any genetic event.

17beta-estradiol induces the proliferation of the in vitro cultured human urothelium

OBJECTIVE

The genitourinary tract is considered to be a target for the actions of sex steroid hormones. Decreased ovarian function and lack of estrogen after menopause are associated with lower genitourinary tract symptoms as well as bladder dysfunctions such as incontinence. Estrogen may also affect urothelial cells. The estrogen receptors (ERs) are found in the mucosa of the urinary tract. The purpose of this study was to culture human urothelial cells (HUCs) originating from urothelial tissue biopsies and to use them as a reproducible test platform to evaluate the effect of 17beta-estradiol (E2).

MATERIAL AND METHODS

Urothelial tissue biopsies were obtained from 95 patients undergoing gynaecological open surgery for urinary incontinence, paediatric vesicoureteral reflux or transurethral resection of the prostate (TURP) for benign prostatic hyperplasia. HUCs originating from biopsies were cultured in vitro in the absence or in the presence of 0.1 nmol, 0.01 micromol and 1 micromol of E2. ER expression of the cultured HUCs was examined by Western analysis and immunofluorescence microscopy, which was also used for HUC characterization. The effect of E2 in the proliferation of the HUCs was determined by tetrazolium salt 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT)-assay.

RESULTS

HUCs were cultured successfully in four to six passages but there was variation between samples. The cultured cells showed expression of beta(4)-integrin, E-cadherin and cytokeratins 7, 8, 9 and 19, indicating the epithelial origin of the cells. Both types of ERs, ERalpha and ERbeta, were found in the in vitro cultured HUCs. E2 treatment of HUCs did not affect remarkably the expression of ERalpha but cell proliferation was induced. However, no concentration-dependent effect was seen.

CONCLUSIONS

This study indicates that HUCs originating from small tissue biopsies can be cultured in several passages in vitro and could have potential in repairing or restoring urinary tract tissue by tissue engineering therapy. HUCs serve as a good in vitro test platform, as shown by analysing E2-treated HUCs. E2 induced the proliferation of cultured HUCs even though concentration dependency was not observed. The findings of this study may have relevance in determining the mechanisms of estrogen therapy in postmenopausal urinary tract symptoms and in the future development of tissue engineering technology.

Expression and significance of androgen receptor coactivators in urothelial carcinoma of the bladder

Urothelial carcinoma (UC) of the bladder is approximately three times more common in men than women. While the etiology for this gender difference in incidence remains unknown, a role for androgen receptor (AR) signaling has been suggested. The mechanisms by which AR activity is regulated in UC cells, however, are largely elusive. Here, we explore the significance of coregulators that are critical for the formation of a functional AR transcriptional complex, in UC cells. Using two AR-positive UC cell lines, TCC-SUP and UMUC3, we demonstrate the expression of the coactivators NCOA1, NCOA2, NCOA3, CREBBP, and EP300 in UC cells. small interfering RNA-mediated knockdown of the AR or any of these coactivators markedly impacted cell viability and abrogated androgen-dependent cell proliferation. Noteworthy, contrary to AR-positive prostate cancer cells, expression of these AR-associated coactivators was not androgen regulated in UC cells. To assess the clinical relevance of coactivator expression, we performed immunohistochemistry on paraffin-embedded sections from 55 patients with UC of the bladder. We found that while 24 out of 55 (44%) of tumors expressed the AR, each of the coactivators was expressed by 85-100% of the bladder cancers. Moreover, we noted a significant downregulation of NCOA1 expression in tumors versus adjacent, non-tumor bladder urothelium, with a mean of 68% (range 0-100) of tumor cells demonstrating NCOA1 staining versus a mean of 81% (range 0-90) of non-tumor cells (P=0.03). Taken together, our data suggest an important role for AR-associated coactivators in UC and point toward differences in the regulation of AR activity between bladder and prostate cancer cells.

The G protein-coupled receptor GPR30 inhibits human urothelial cell proliferation

We have previously shown that estrogen stimulates cell proliferation in both normal and transformed urothelial cells mainly through activation of the two primary estrogen receptors (ERs), ERalpha and ERbeta. A growing body of evidence suggests that estrogen also initiates nongenomic effects that cannot be explained by activation of primary ERs. In the present study, we observed that urothelial cells express high amounts of GPR30, a G protein-coupled receptor recently identified as a candidate for membrane-associated estrogen binding. Membrane- impermeable bovine serum albumin-conjugated 17beta-estradiol and the specific GPR30 agonist G-1 both inhibited urothelial cell proliferation in a concentration-dependent manner. Transient overexpression of GPR30 inhibited 17beta-estradiol (E2)-induced cell proliferation. Decreased GPR30 expression caused by specific small interfering RNA increased E2-induced cell proliferation. These results indicate that membrane-associated inhibitory effects of E2 on cell proliferation correlate with abundance of GPR30. Although E2 induced a significant increase in caspase-3/7 activity, G-1 did not, suggesting that the GPR30-mediated inhibitory effect on cell proliferation was not caused by apoptosis. Furthermore, we found that G-1 failed to induce c-fos, c-jun, and cyclin D1 expression, and GPR30 overexpression abolished E2-induced c-fos, c-jun, and cyclin D1 expression. However, inactivation of GPR30 by small interfering RNA increased c-fos, c-jun, and cyclin D1 expression. These results suggest that GPR30-mediated inhibition of urothelial cell proliferation is the result of decreased cyclin D1 by down-regulation of activation protein-1 signaling.