Serum GDF9 and BMP15 as potential markers of ovarian function in women with and without polycystic ovary syndrome.

OBJECTIVE: Growth differentiation factor-9 (GDF9) and bone morphogenetic protein-15 (BMP15) are critical paracrine regulators of female fertility and are predominantly expressed by oocytes. However, it is unknown if serum concentrations reflect changes in ovarian function and/or reproductive endocrine disorders. This study aimed to determine if serum GDF9/BMP15 are associated with ovarian, pituitary, oestrogenic, androgenic and metabolic characteristics and the ovarian pathologies, polycystic ovarian morphology (PCOM) and polycystic ovary syndrome (PCOS). DESIGN: Women aged 21-45 years (n = 381) were included from a cross-sectional study at the National University Hospital, Singapore. PATIENTS: Participants were volunteers and patients with possible PCOS. MEASUREMENTS: Anthropometric measurements, transvaginal ultrasound scans and serum sampling were performed and a questionnairecompleted. Serum GDF9 and BMP15 concentrations were matched with menstrual cycle length, ovarian protein and steroid hormone production, pituitary hormone production and metabolic assessments in women with PCOM or PCOS and those with neither (control). RESULTS: Serum GDF9 and BMP15 were detectable in 40% and 41% of women, respectively and were positively correlated with each other (r = 0.08, p = 0.003). GDF9, but not BMP15, was positively correlated with ovarian volume (p = 0.02) and antral follicle count (AFC) (p = 0.004), but not with anti-Müllerian hormone (p = 0.05). However, serum GDF9 and BMP15 concentrations were not significantly different between control, PCOM and PCOS women, nor associated with androgenic or metabolic PCOS features. However, the relationship between GDF9 and AFC differed between control, PCOM and PCOS women (p = 0.02). CONCLUSIONS: Serum GDF9 and BMP15 concentrations somewhat reflect ovarian but not androgenic or metabolic characteristics of PCOS, with increased GDF9 reflecting high AFC as seen in PCOM/PCOS.

Individual and combined associations of sarcopenia, osteoporosis and obesity with frailty in a multi-ethnic asian older adult population.

BACKGROUND: We explored the relationships between sarcopenia (SP), osteoporosis (OP), obesity (OB), (alone and in combination) with physical frailty (PF) in a multi-ethnic, population-based study of Asians aged ≥ 60 years. METHODS: Participants were enrolled from the PopulatION HEalth and Eye Disease PRofile in Elderly Singaporeans Study (PIONEER) study. PF was defined using the modified Fried phenotype; SP using the Asian Working Group for Sarcopenia 2019; OP using bone mineral density scores; and OB using the fat mass index. Modified Poisson regression models investigated the associations between exposures and PF, and the relative excess rates of PF due to interactions (RERI) to determine synergistic or antagonistic interactions. RESULTS: Of the 2643 participants, 54.8% was female; and 49.8%, 25.1%, 25.0% were Chinese, Indians, and Malays, respectively. 25%, 19.0% and 6.7% participants had OB only, SP only, and OP only, respectively. A total of 356 (17.5%), 151 (7.4%) and 97 (4.8%) had osteosarcopenia (OSP), sarcopenic obesity (SOB) and osteo-obesity (OOB), respectively; while 70 (3.5%) had all 3 morbid conditions (osteosarcopenic obesity, OSO). Both SP only and OB only were strongly associated with increased rates of PF (RR: 2.53, 95% CI: 1.95, 3.29; RR: 2.05, 95% CI: 1.58, 2.66 respectively); but not OP. Those with OSP, OOB and SOB were also associated with high risks of PF (RR: 2.82, 95% CI: 2.16, 3.68; RR: 2.34, 95% CI: 1.69, 3.23; and RR: 2.58, 95% CI: 1.95, 3.41, respectively) compared to robust individuals. Critically, individuals with OSO had the highest relative risk of having PF (RR: 3.06, CI: 2.28, 4.11). Only the sarcopenia-obesity interaction was significant, demonstrating negative synergism (antagonism). The concurrent presence of SP and OB was associated with a 100% lower rate of PF compared to the sum of the relatively rates of SP only and OB only. CONCLUSION: The prevalence of SP, OB and OP, alone and combined, is substantial in older Asians and their early identification is needed to mitigate the risk of frailty. OB may interact with SP in an antagonistic manner to moderate rates of frailty. Further longitudinal studies are needed to address causality and mechanistic underpinnings our findings.

Effect of body mass index (BMI) on phenotypic features of polycystic ovary syndrome (PCOS) in Singapore women: a prospective cross-sectional study.

BACKGROUND: A diagnosis of Polycystic Ovary Syndrome (PCOS) and its related phenotypic features including increased hair growth can affect a woman's social and emotional well-being. We aim to determine firstly, if excess body weight affects menstrual cycle length, excessive hair growth and other phenotypic features in healthy women without PCOS and secondly, whether having PCOS exacerbates the effects of high body mass index (BMI). METHODS: A prospective cross-sectional study involving healthy women (21-45 years) recruited at an annual health screen for hospital staff and volunteers from the university community, and PCOS cases referred to tertiary gynecological clinics in Singapore. To dissect the independent and/or combinatorial effects of PCOS and BMI on the phenotypic features, subjects were divided into four categories: non-PCOS (normal BMI), non-PCOS (high BMI), PCOS (normal BMI), and PCOS (high BMI). General linear modelling was performed to compare clinical, ovarian, hormonal and metabolic parameters across these four categories. RESULTS: Of 389 participants, 134 (34.4%) were classified as PCOS and the remaining 255 (65.6%), as the non-PCOS population. Overall 45.2% of women had high BMI (≥ 23). Compared to non-PCOS subjects, women with PCOS had a higher BMI (mean (SD): 25.14 ± 6.46 vs 23.08 ± 4.36, p < 0.001). Women with PCOS and high BMI had increased hair growth with modified Ferriman-Gallwey (mFG) scores that were 2.96-fold higher versus healthy-normal BMI women (mean difference; 1.85, 95% CI 0.80-2.90). Compared to healthy-high BMI women, PCOS women with high BMI had significantly higher mean differences in mFG scores (1.79, 95% CI 0.64-2.93). In PCOS women, having high BMI also significantly increased mFG scores by 1.85-fold (mean difference; 1.82. 95% CI 0.52-3.12). This effect was mirrored by the additive effect of BMI and PCOS on free androgen index. No independent effect of high BMI on rates of oligomenorrhoea, antral follicle count, ovarian volume or serum androgens were observed. CONCLUSIONS: We observed an additive effect of body weight to increase hair growth in women with PCOS. Maximum mFG scores were present in PCOS women with high BMI. Such increases in mFG score may affect the self-esteem of women with PCOS.

Risk factors and prevalence of urinary incontinence in mid-life Singaporean women: the Integrated Women's Health Program.

INTRODUCTION AND HYPOTHESIS: The objective was to identify the prevalence and risk factors for urinary incontinence (UI) in healthy midlife Singaporean women. METHODS: Healthy women, aged 45-69 years, were assessed for UI and sociodemographic characteristics, including ethnicity, menopausal status, parity, and body mass index (BMI). UI subtypes corresponding to stress (SUI) alone, urge (UUI) alone, mixed (MUI), and leakage (drops only) incontinence were classified using the Urinary Distress Inventory 6 (UDI-6). Risk factors were examined using Chi-squared tests, followed by sequential multivariate logistic regression to estimate adjusted odds ratios (aOR and 95% confidence intervals). RESULTS: A total of 1,119 women (mean age 56.2 ± 5.2) completed the UDI-6. 52.3% reported any UI; MUI and SUI were the most common, each affecting 20% of women. Post-menopausal women had a lower risk (aOR 0.5 [0.3-0.9]) of SUI, but a higher risk (aOR 4.4 [1.0-19.9]) of UUI compared with premenopausal women. Higher education was negatively associated (aOR 0.3 [0.2-0.7]) with UUI, but positively associated with MUI (aOR 2.3 [1.3-4.0]). Parity (1-2 children) increased the risk of SUI (aOR 1.8 [1.0-3.1]), but reduced the risk of UUI (aOR 0.4 [0.2-0.9]). Obesity was associated with increased risk for MUI (aOR 2.2 [1.4-3.4]) and leakage (aOR 2.0 [1.0-4.1]). Malays and Indians had a higher risk of MUI, having (aOR 2.1 (1.2-3.7) and 1.7 (1.1-2.7) respectively compared with Chinese, a difference mediated by higher BMI. CONCLUSION: Urinary incontinence is a major morbidity prevalent in healthy midlife Asian women. Post-menopausal status, education level, parity, BMI (and its link with ethnicity) are independent risk factors in this population, and should be incorporated into counseling and targeted interventions.

Factors associated with re-initiation of antidepressant treatment following discontinuation during pregnancy: a register-based cohort study.

Antidepressant treatment when facing a pregnancy is an important issue for many women and their physicians. We hypothesized that women with a greater burden of pre-pregnancy psychiatric illness would be more likely to re-initiate antidepressants following discontinuation of treatment during pregnancy. A register-based cohort study was carried out including 38,595 women who gave birth between the 1st of January 2007 and the 31st of December 2014, who had filled a prescription for an antidepressant medication in the year prior to conception. Logistic regressions were used to explore associations between maternal characteristics and antidepressant treatment discontinuation or re-initiation during pregnancy. Most women discontinued antidepressant treatment during pregnancy (n = 29,095, 75.4%), of whom nearly 12% (n = 3434, 11.8%) re-initiated treatment during pregnancy. In adjusted analyses, parous women (aOR 1.22, 95% CI 1.12-1.33), with high educational level (aOR 1.21, 95% CI 1.08-1.36); born within the EU (excluding Nordic countries, aOR 1.41, 95% CI 1.03-1.92) or a Nordic country (aOR 1.42, 95% CI 1.22-1.65); who more often reported prior hospitalizations due to psychiatric disorders (aOR 1.50, 95% CI 1.10-2.03, for three or more episodes); and had longer duration of pre-pregnancy antidepressant use (aOR 6.10, 95% CI 5.48-6.77, for >2 years antidepressant use), were more likely to re-initiate antidepressants than were women who remained off treatment. Women with a greater burden of pre-pregnancy psychiatric illness were more likely to re-initiate antidepressants. Thus, pre-pregnancy psychiatric history may be particularly important for weighing the risks and benefits of discontinuing antidepressants during pregnancy.

Structural basis for molecular recognition of folic acid by folate receptors.

Folate receptors (FRα, FRß and FRγ) are cysteine-rich cell-surface glycoproteins that bind folate with high affinity to mediate cellular uptake of folate. Although expressed at very low levels in most tissues, folate receptors, especially FRα, are expressed at high levels in numerous cancers to meet the folate demand of rapidly dividing cells under low folate conditions. The folate dependency of many tumours has been therapeutically and diagnostically exploited by administration of anti-FRα antibodies, high-affinity antifolates, folate-based imaging agents and folate-conjugated drugs and toxins. To understand how folate binds its receptors, we determined the crystal structure of human FRα in complex with folic acid at 2.8 Å resolution. FRα has a globular structure stabilized by eight disulphide bonds and contains a deep open folate-binding pocket comprised of residues that are conserved in all receptor subtypes. The folate pteroate moiety is buried inside the receptor, whereas its glutamate moiety is solvent-exposed and sticks out of the pocket entrance, allowing it to be conjugated to drugs without adversely affecting FRα binding. The extensive interactions between the receptor and ligand readily explain the high folate-binding affinity of folate receptors and provide a template for designing more specific drugs targeting the folate receptor system.

Pharmacokinetics of Prenylflavonoids following Oral Ingestion of Standardized Epimedium Extract in Humans.

Leaves of the Epimedium plant are traditionally consumed for bone health and other indications. The aim of this study was to establish the safety and pharmacokinetics of the metabolites of prenylflavonoids (icariin, icariside I, icariside II, icaritin, and desmethylicaritin) following single doses of a defined Epimedium prenylflavonoid extract in humans. A single oral dose of 370, 740, or 1110 mg of a standardized Epimedium prenylflavonoid extract was administered to 30 healthy male subjects in a randomized, placebo-controlled trial. Serum samples were collected over a 48-h period and analyzed by liquid chromatography-tandem mass spectrometry and non-compartmental pharmacokinetic modelling. Epimedium prenylflavonoid extracts were well tolerated and no adverse effects were observed. The principle metabolites detected in the serum were icariside II and desmethylicaritin. Icariside II had a T max of between 4.1 - 4.3 h, reaching a maximum AUC0→∞ of 23.0 (17.5, 29.9) h×ng/mL (median [IQR: interquartile range]) with the highest dose of the Epimedium prenylflavonoid. On the other hand, desmethylicaritin had a delayed T max of 24.1 - 24.4 h and reached a maximum AUC0→∞ of 126.1 (62.4, 202.9) h×ng/mL. The median maximum plasma concentration and AUC0→∞ of desmethyliciaritin showed an increase with higher doses of the Epimedium prenylflavonoid (p < 0.05). Icariin, icariside I, and icaritin levels were below detection limits. Levels of Epimedium prenylflavonoid metabolites observed in this study were consistent with levels demonstrated to have anti-osteoporotic effects in cellular and animal studies. Coupled with the favorable safety profile of the extract observed, further studies are required to explore the utility of Epimedium prenylflavonoid extracts to prevent osteoporosis in postmenopausal women.

Smart Phone APP to Restore Optimal Weight (SPAROW): protocol for a randomised controlled trial for women with recent gestational diabetes.

BACKGROUND: Gestational diabetes (GDM) is a known risk factor for type 2 diabetes mellitus (T2DM), and women with a history of GDM have a 7-fold increased risk of developing the disease. Achieving a healthy weight post-delivery is key in reducing the risk of future diabetes in these women. The aim of this trial is to investigate the use of an interactive smartphone application (APP) to restore women to optimal weight following delivery. METHODS: This will be an open-label randomized controlled trial. Two hundred women with gestational diabetes will be randomized to receive the intervention or standard care following delivery. Participants will be reviewed at 6 weeks and 4 months post-delivery. The intervention is an APP serving as a platform for weight, diet and physical activity tracking. The APP provides 3-5 min educational videos suggesting suitable lifestyle adjustments relevant to postnatal period such as breast feeding, diet and exercise. Lastly, the APP will allow real-time interaction between users and the team of dietitians, physiotherapists and occupational therapists to encourage restoration of optimal weight. Women in the control arm will be informed about the increased risk of developing T2DM and advised to maintain a healthy weight. Primary outcome measure is the restoration of participants' booking weight if booking BMI ≤ 23, or weight loss of at least 5% from booking weight if booking BMI > 23 over the 4 month period. Secondary outcome measures will assess serum metabolic and inflammatory markers, quality of life via questionnaires and cost-effectiveness of the intervention at each follow-up visit. DISCUSSION: This will be the first randomised controlled trial investigating the use of a smartphone application for postpartum weight loss in women with gestational diabetes. The major ethnic groups in our study population represent the majority of ethnic groups in Asia, amongst which the prevalence of diabetes is high. If shown to be effective, this APP may be used in wider clinical settings to improve postpartum weight loss and reduce the risk of developing T2DM in these women. TRIAL REGISTRATION: This study was registered on clintrials.gov on the 30th of October 2017, under the trial registration number: NCT03324737 .

Simplified 4-item criteria for polycystic ovary syndrome: A bridge too far?

OBJECTIVES: Although the Rotterdam 2003 polycystic ovarian syndrome (PCOS) diagnostic criteria is widely used, the need to consider multiple variables makes it unwieldy in clinical practice. We propose a simplified PCOS criteria wherein diagnosis is made if two of the following three items were present: (i) oligomenorrhoea, (ii) anti-mullerian hormone (AMH) above threshold and/or (iii) hyperandrogenism defined as either testosterone above threshold and/or the presence of hirsutism. DESIGN SETTING AND PARTICIPANTS: This prospective cross-sectional study consists of healthy women (n = 157) recruited at an annual hospital health screen for staff and volunteers from the university community, and a patient cohort (n = 174) comprising women referred for suspected PCOS. MAIN OUTCOME MEASURES: We used the healthy cohort to establish threshold values for serum testosterone, antral follicle counts (AFC), ovarian volume (OV) and AMH. Women from the patient cohort, classified as PCOS by simplified PCOS criteria, AMH alone and Rotterdam 2003, were compared with respect to prevalence of oligomenorrhoea, hyperandrogenism and metabolic indices. RESULTS: In healthy women, testosterone ≥1.89 nmol/L, AFC ≥22 follicles and OV ≥8.44 mL, best predicted oligomenorrhoea and were used as threshold values for PCOS criteria. An AMH level ≥37.0 pmol/L best predicted polycystic ovarian morphology. AMH alone as a single biomarker demonstrated poor specificity (58.9%) for PCOS compared to Rotterdam 2003. In contrast, there was a 94% overlap in women selected as PCOS by the simplified PCOS criteria and Rotterdam 2003. The population characteristics of these two groups of PCOS women showed no significant mean differences in androgenic, ovarian, AMH and metabolic (BMI, HOMA-IR) variables. CONCLUSIONS: Our data recommend the simplified PCOS criteria with population-specific thresholds for diagnosis of PCOS. Its ability to replace ovarian ultrasound biometry with the highly correlated variable AMH, and use of testosterone as a single marker for hyperandrogenaemia alongside the key symptoms of oligomenorrhoea and hirsutism confers significant clinical potential for the diagnosis of PCOS.

Trends and predictors of cesarean birth in Singapore, 2005-2014: A population-based cohort study.

BACKGROUND: Rates of cesarean birth have continued to rise in many high-income countries. We examined the temporal trends and predictors of cesarean birth in Singapore. METHODS: Linked hospitalization and Birth Registry data were used to examine all live births to Singaporean citizens and permanent residents between January 1, 2005 and December 31, 2014 (n = 342 932 births). We calculated cesarean rates and age-adjusted average annual percent change (AAPC) in those rates and used sequential multivariable regression modeling to assess the contribution of changes in predictors to the change in cesarean rates over time. RESULTS: The overall cesarean rate in Singapore rose from 32.2% in 2005 to 37.4% in 2014. Among singleton, cephalic, term pregnancies, the two major predictions of cesarean were nulliparity and previous cesarean, each accounting for just over one-third of all cesareans. Higher AAPC was observed in nulliparous women of Indian ethnicity (0.74% [95% confidence interval 0.68-0.80]) compared with Chinese (0.62% [0.60-0.65]) or Malay women (0.63% [0.59-0.68]), and in women who delivered in private hospitals (0.62% [0.60-0.64]) compared with those delivered under subsidized care in public hospitals (0.58% [0.52-0.63]). Parity and education had the largest influences on cesarean birth trend (attenuation of AAPC from 0.62% [0.59-0.66] to 0.39% [0.38-0.40] after adjustment). CONCLUSION: Cesarean birth has continued to rise at a steady rate in Singapore. Strategies to curb this temporal increase include avoidance of medically unnecessary primary cesarean and attempts at trial of labor and vaginal delivery among women with a history of prior cesarean.

Icaritin suppresses development of neuroendocrine differentiation of prostate cancer through inhibition of IL-6/STAT3 and Aurora kinase A pathways in TRAMP mice.

Neuroendocrine prostate cancer (NEPC) has a poor prognosis, with a median survival of less than 1 year after diagnosis. Following androgen deprivation therapy, prostate adenocarcinoma cells have been observed to develop an androgen receptor-negative, terminally differentiated and indolent neuroendocrine-like phenotype. However, several molecular events, including interleukin 6 (IL-6) stimulation, in the prostate microenvironment result in the appearance of aggressive, highly proliferative castrate-resistant NEPC. In this study, we examined the mechanistic effects of a natural prenylflavonoid, icaritin (ICT), on neuroendocrine differentiation in IL-6-induced LNCaP cells and NEPC development in the male transgenic adenocarcinoma of the mouse prostate (TRAMP) model. TRAMP mice received daily intraperitoneal injection of ICT or vehicle. ICT induced apoptosis in prostate tumor, suppressed NEPC development and, accordingly, improved overall survival in TRAMP mice. Expression of neuroendocrine markers (synaptophysin) and androgen receptor in TRAMP mice and neuroendocrine-like LNCaP cells were inhibited by ICT. Suppression of neuroendocrine and NEPC development by ICT was associated with dose-dependent inhibitory effects on abnormally elevated IL-6/STAT3 and Aurora kinase A in vitro and in vivo Since ICT demonstrated favorable pharmacokinetic and safety profiles with marked enrichment in prostate tissues, our study provides evidence for the development of prenylflavonoid as a multimodal therapeutic agent against NEPC.

Antimüllerian hormone, antral follicle count and ovarian volume predict menstrual cycle length in healthy women.

OBJECTIVE: Although menstrual cycle length is one of the main concerns of women and may have important health consequences, little is known about its predictors. The aim of this study was to identify predictors of menstrual cycle length variability in healthy women. DESIGN: Prospective cross-sectional study. PATIENTS: Two hundred healthy women aged 21-45. MEASUREMENTS: A questionnaire was administered to determine lifestyle factors. Ovarian parameters, metabolic parameters, pituitary hormones, sex steroids and antimüllerian hormone (AMH) were measured. RESULTS: Women with long (≥35 days) and normal (25-34 days) menstrual cycles had >5-fold and >2-fold higher serum AMH levels, respectively, compared to those with short cycles (<25 days). Menstrual cycle length was associated with age but not lifestyle factors. Only one factor group (AMH, antral follicle count [AFC], ovarian volume, testosterone and LH) was significantly associated with menstrual cycle length. Within this factor group, only the ovarian parameters (AMH, AFC, ovarian volume) predicted menstrual cycle length. Each SD increase in AMH (32·9 pmol/l) and ovarian volume (2·29 cm(3) ) was associated with 2·80-fold (95% CI: 1·67-4·69) and 1·62-fold (95% CI: 1·08-2·43) increased risks, respectively, for longer menstrual cycles. CONCLUSIONS: AMH, AFC and ovarian volume are positively associated with menstrual cycle length in healthy women. Our identification of AMH as an independent predictor of menstrual cycle length puts forth a new notion of utilizing menstrual cycle length to predict possible AMH-dependent/-associated outcomes. In addition, this novel relationship may facilitate the interpretation of AMH levels and its clinico-pathological significance across different centres.

Polymorphisms of anti-Müllerian hormone signaling pathway in healthy Singapore women: population differences, endocrine effects and reproductive outcomes.

In order to study the association of genetic polymorphisms of anti-Müllerian hormone (AMH) signaling pathway with endocrine changes and pregnancy outcomes, a total of 213 women of reproductive ages were recruited according to our inclusion and exclusion criteria between November 2011 and September 2014 in Singapore. Genotyping studies were performed using a minor groove binder primer/probe Taqman assay. The allele frequencies of the AMH Ile(49)Ser and AMHR2 -482A > G polymorphisms were analyzed in relation to female reproductive hormone levels, ovarian parameters, menstrual cycle lengths and pregnancy outcomes. AMH Ser allele frequency and AMHR2 G allele frequency of our Singapore population were compared with those of other populations reported in HapMap. The genotype distributions and allele frequencies for the AMH Ile(49)Ser and AMHR2 -482A > G polymorphisms were not associated with estradiol (E2) levels, ovarian parameters, menstrual cycle length, or pregnancy outcomes in our cohort. Our findings suggest that genetic variants in the AMH signal transduction pathway have population differences but do not appear to have significant effects on ovarian, endocrine, metabolic parameters and reproductive outcomes.

A novel prostate cancer therapeutic strategy using icaritin-activated arylhydrocarbon-receptor to co-target androgen receptor and its splice variants.

Persistent androgen receptor (AR) signaling is the key driving force behind progression and development of castration-resistant prostate cancer (CRPC). In many patients, AR COOH-terminal truncated splice variants (ARvs) play a critical role in contributing to the resistance against androgen depletion therapy. Unfortunately, clinically used antiandrogens like bicalutamide (BIC) and enzalutamide (MDV), which target the ligand binding domain, have failed to suppress these AR variants. Here, we report for the first time that a natural prenylflavonoid, icaritin (ICT), can co-target both persistent AR and ARvs. ICT was found to inhibit transcription of key AR-regulated genes, such as KLK3 [prostate-specific antigen (PSA)] and ARvs-regulated genes, such as UBE2C and induce apoptosis in AR-positive prostate cancer (PC) cells. Mechanistically, ICT promoted the degradation of both AR and ARvs by binding to arylhydrocarbon-receptor (AhR) to mediate ubiquitin-proteasomal degradation. Therefore, ICT impaired AR transactivation in PC cells. Knockdown of AhR gene restored AR stability and partially prevented ICT-induced growth suppression. In clinically relevant murine models orthotopically implanted with androgen-sensitive and CRPC cells, ICT was able to target AR and ARvs, to inhibit AR signaling and tumor growth with no apparent toxicity. Our results provide a mechanistic framework for the development of ICT, as a novel lead compound for AR-positive PC therapeutics, especially for those bearing AR splice variants.

AP-2γ regulates oestrogen receptor-mediated long-range chromatin interaction and gene transcription.

Oestrogen receptor α (ERα) is key player in the progression of breast cancer. Recently, the cistrome and interactome of ERα were mapped in breast cancer cells, revealing the importance of spatial organization in oestrogen-mediated transcription. However, the underlying mechanism of this process is unclear. Here, we show that ERα binding sites (ERBS) identified from the Chromatin Interaction Analysis-Paired End DiTag of ERα are enriched for AP-2 motifs. We demonstrate the transcription factor, AP-2γ, which has been implicated in breast cancer oncogenesis, binds to ERBS in a ligand-independent manner. Furthermore, perturbation of AP-2γ expression impaired ERα DNA binding, long-range chromatin interactions, and gene transcription. In genome-wide analyses, we show that a large number of AP-2γ and ERα binding events converge together across the genome. The majority of these shared regions are also occupied by the pioneer factor, FoxA1. Molecular studies indicate there is functional interplay between AP-2γ and FoxA1. Finally, we show that most ERBS associated with long-range chromatin interactions are colocalized with AP-2γ and FoxA1. Together, our results suggest AP-2γ is a novel collaborative factor in ERα-mediated transcription.

A gate-latch-lock mechanism for hormone signalling by abscisic acid receptors.

Abscisic acid (ABA) is a ubiquitous hormone that regulates plant growth, development and responses to environmental stresses. Its action is mediated by the PYR/PYL/RCAR family of START proteins, but it remains unclear how these receptors bind ABA and, in turn, how hormone binding leads to inhibition of the downstream type 2C protein phosphatase (PP2C) effectors. Here we report crystal structures of apo and ABA-bound receptors as well as a ternary PYL2-ABA-PP2C complex. The apo receptors contain an open ligand-binding pocket flanked by a gate that closes in response to ABA by way of conformational changes in two highly conserved beta-loops that serve as a gate and latch. Moreover, ABA-induced closure of the gate creates a surface that enables the receptor to dock into and competitively inhibit the PP2C active site. A conserved tryptophan in the PP2C inserts directly between the gate and latch, which functions to further lock the receptor in a closed conformation. Together, our results identify a conserved gate-latch-lock mechanism underlying ABA signalling.

Androgen receptor: structure, role in prostate cancer and drug discovery.

Androgens and androgen receptors (AR) play a pivotal role in expression of the male phenotype. Several diseases, such as androgen insensitivity syndrome (AIS) and prostate cancer, are associated with alterations in AR functions. Indeed, androgen blockade by drugs that prevent the production of androgens and/or block the action of the AR inhibits prostate cancer growth. However, resistance to these drugs often occurs after 2-3 years as the patients develop castration-resistant prostate cancer (CRPC). In CRPC, a functional AR remains a key regulator. Early studies focused on the functional domains of the AR and its crucial role in the pathology. The elucidation of the structures of the AR DNA binding domain (DBD) and ligand binding domain (LBD) provides a new framework for understanding the functions of this receptor and leads to the development of rational drug design for the treatment of prostate cancer. An overview of androgen receptor structure and activity, its actions in prostate cancer, and how structural information and high-throughput screening have been or can be used for drug discovery are provided herein.

The Prevalence of Gestational Diabetes Mellitus Among Asian Females is Lower Using the New 2013 World Health Organization Diagnostic Criteria.

OBJECTIVE: To determine the impact of the new 2013 World Health Organization (WHO) criteria for gestational diabetes mellitus (GDM) diagnosis on GDM prevalence and pregnancy outcomes in Asian ethnic groups compared to the 1999 WHO criteria. METHODS: A retrospective cohort study included 855 pregnant females of Chinese, Malay, and Asian Indian ethnicity at high risk of GDM who underwent 75-g oral glucose tolerance tests (OGTTs) between July 2008 and June 2010 in a tertiary center in Singapore. GDM prevalence, reclassification, and pregnancy outcomes were determined using the 2013 and 1999 diagnostic cutoffs for fasting and 2-hour postglucose (PG) values. RESULTS: The prevalence of GDM was reduced from 28.8% to 21.1% when the 2013 criteria were used. Overall, 10.2% subjects were reclassified from GDM to normal using the 2013 criteria, and 2.6% were reclassified from normal to GDM, giving a net reclassification rate of 12.8%. Reclassification from GDM to normal was greatest among Chinese, followed by Asian Indians, but the prevalence rate was unchanged among Malays. Babies of mothers who were reclassified from normal to GDM were more likely to have birth weight >95th centile and shoulder dystocia. CONCLUSION: The prevalence of GDM was reduced when the 2013 criteria were used, with the greatest reduction seen among Chinese, followed by Asian Indians. Lowering the fasting cutoff as per the new criteria identified a select group of patients who might benefit from GDM treatment. However, raising the 2-hour PG cutoff would miss a significant number of patients who might potentially benefit from GDM treatment.

Selective estrogen receptor modulator effects of epimedium extracts on breast cancer and uterine growth in nude mice.

Epimedium is popularly used in traditional Chinese medicine to treat sexual dysfunction, menstrual irregularity, and osteoporosis. The estrogenic effects of the prenylated flavonoids of Epimedium make it an attractive alternative for hormone replacement therapy. Here, we examined the therapeutic potential of the estrogenic herb extract of Epimedium brevicornum as an alternative to hormone replacement therapy in a breast cancer mouse model. To that end, athymic and ovariectomized female nude mice were subcutaneously injected into the mammary fat pads with MCF-7 breast cancer cells, randomly grouped and fed with soy-free feeds, alone or in combination with ethinyl estradiol or different doses of the estrogenic herb extract of E. brevicornum. Our findings demonstrate that unlike ethinyl estradiol, it did not promote the growth of breast cancer xenograft volume and weight, with the highest dose showing a significant reduction in growth and ERα protein content. Moreover, the extract increased uterine weight at the lowest dose, while higher doses had no effects. Put together, our data shows for the first time that despite the estrogenic activity of E. brevicornum, its action is largely tissue specific and dose-dependent. Our data on E. brevicornum presents in vivo evidence for its selective estrogen receptor modulator effect and warrants exploration of its use as an alternative to hormone replacement therapy in menopausal women.

Structural basis for basal activity and autoactivation of abscisic acid (ABA) signaling SnRK2 kinases.

Abscisic acid (ABA) is an essential hormone that controls plant growth, development, and responses to abiotic stresses. Central for ABA signaling is the ABA-mediated autoactivation of three monomeric Snf1-related kinases (SnRK2.2, -2.3, and -2.6). In the absence of ABA, SnRK2s are kept in an inactive state by forming physical complexes with type 2C protein phosphatases (PP2Cs). Upon relief of this inhibition, SnRK2 kinases can autoactivate through unknown mechanisms. Here, we report the crystal structures of full-length Arabidopsis thaliana SnRK2.3 and SnRK2.6 at 1.9- and 2.3-Å resolution, respectively. The structures, in combination with biochemical studies, reveal a two-step mechanism of intramolecular kinase activation that resembles the intermolecular activation of cyclin-dependent kinases. First, release of inhibition by PP2C allows the SnRK2s to become partially active because of an intramolecular stabilization of the catalytic domain by a conserved helix in the kinase regulatory domain. This stabilization enables SnRK2s to gain full activity by activation loop autophosphorylation. Autophosphorylation is more efficient in SnRK2.6, which has higher stability than SnRK2.3 and has well-structured activation loop phosphate acceptor sites that are positioned next to the catalytic site. Together, these data provide a structural framework that links ABA-mediated release of PP2C inhibition to activation of SnRK2 kinases.