The Evolutionary Tale and Future Directions of Aromatase Inhibitors in Breast Carcinoma.

Aromatase inhibitors have often been likened to that of 'medical scalpels' for the treatment of breast carcinoma. By inhibiting the singular step of aromatisation, they have proven to be extremely effective allies in the treatment of breast cancer among postmenopausal women. However, their relevance soon may not be limited to the post-menopausal age group alone. Recent studies have hinted at their utility amongst the premenopausal women; combined with ovarian ablation techniques, aromatase inhibitors may prove to be equally effective and more, as compared to tamoxifen in this age-group. Additionally, explorations aimed at ascertaining their potential utility as an effective preventive strategy against breast carcinoma have yielded encouraging results. However, for aromatase inhibitors to be able to attain their full potential, further strategic fine-tuning aimed at maximising their efficacy and minimising their potentially far-reaching adverse effects, is the need of the hour. Despite the recent diversification, the issue of resistance to aromatase inhibitors in breast cancer threatens to derail the advances so gained till date. Fortunately, a few novel ploys have come to the fore, for instance combining aromatase inhibitors with HER-2 antibodies that could potentially help circumvent the menace of resistance in the near future. Till date, the utility of aromatase inhibitors can at best be described as onedimensional. However, with the unearthing of potential new avenues for its application, this assortment of molecules today stands on the precipice of ushering in a new revolution in the treatment of breast carcinoma.

Comparison of clinical and hormonal characteristics among four phenotypes of polycystic ovary syndrome based on the Rotterdam criteria.

PURPOSE: Polycystic Ovary Syndrome (PCOS) is the most common endocrine disturbances in women and is divided into different phenotypes. The aim of study is to compare the clinical and hormonal parameters among the four phenotypes of PCOS based on the Rotterdam criteria and with control group. METHODS: Women with PCOS (n = 263) confirmed based on the Rotterdam criteria and 263 women with no evidence of PCOS were recruited as controls using observational case-control study. Evaluation of clinical and hormonal parameters, and differences in anti-Mullerian hormone (AMH) were compared between four phenotypes of PCOS and controls. RESULTS: Women with phenotype A (olig-anovulation (O) + hyperandrogenism (H) + polycystic ovary morphology (P)) had significantly larger waist than phenotype D (O + P) and higher body mass index than phenotype C (H + P). The LH/FSH ratio was significantly higher in phenotype A than phenotype D and controls along with significantly higher serum total testosterone levels in phenotype A compared to the phenotype B (O + H), C, D, and controls. AMH was significantly higher with phenotype A, C, and D than in women phenotype B and controls. CONCLUSIONS: The highest AMH levels were found in phenotype A. Phenotype B similar to controls had significantly low AMH compared to other three PCOS phenotypes. Women in the phenotypes D and controls showed significantly lower levels of LH/FSH ratio, total testosterone, and free androgen index, and higher levels of FSH and SHBG compared with phenotype A (P < 0.001). In logistic regression analysis, AMH and LH were predictors for PCOS.

A case-control observational study of insulin resistance and metabolic syndrome among the four phenotypes of polycystic ovary syndrome based on Rotterdam criteria.

BACKGROUND: Polycystic ovary syndrome (PCOS) is associated with an increased risk of insulin resistance (IR), metabolic syndrome (MetS), impaired glucose tolerance (IGT) and type 2 diabetes mellitus (T2DM). Metabolic aspects of the four PCOS phenotypes remain to be fully defined. The aim of this study was to compare metabolic parameters and insulin resistance among the four PCOS phenotypes defined according to the Rotterdam criteria and to determine predictors of these complications. METHODS: A total of 526 reproductive-aged women were included in this observational case-control study. Of these, 263 were diagnosed as a PCOS based on Rotterdam criteria and 263 infertile women with no evidence of PCOS were recruited as controls. Biochemical, metabolic and insulin resistance parameters were compared in the two groups and the frequency of MetS and IR were compared among the four phenotypes. Data were analyzed for statistical significance using Student's t-test and one way analysis of variance followed by a post-hoc test (least significant difference). Chi-square tests were used to compare proportions. Univariate and multivariate logistic regression analyses were also applied. RESULTS: IR was identified in 112 (42.6%) of the PCOS women and 45 (17.1%) of the control (P <0.001). There were no significant differences in the frequency of IR and MetS between the four PCOS phenotypes. Homeostatic model assessment for IR (HOMA-IR) ≥3.8 was the most common IR parameter in PCOS and control groups. Women with oligo-anovulation (O) and PCO morphology (P) had a significantly lower level of 2-h postprandial insulin compared to women with O, P and hyperandrogenism (H) phenotypes. Logistic regression analysis showed that body mass index, waist circumference, triglyceride/high-density lipoprotein ratio (cardiovascular risk), HOMA-IR and glucose abnormalities (T2DM) were associated with increased risk of having MetS (P < 0.05). CONCLUSIONS: PCOS women with (O + P) show milder endocrine and metabolic abnormalities. Although, there were no significant differences in IR, MetS and glucose intolerance between the four PCOS phenotypes, women with PCOS are at higher risk of impaired glucose tolerance and undiagnosed diabetes.

High-throughput RNA FISH analysis by imaging flow cytometry reveals that pioneer factor Foxa1 reduces transcriptional stochasticity.

Genes are regulated at the single-cell level. Here, we performed RNA FISH of thousands of cells by flow cytometry (flow-RNA FISH) to gain insight into transcriptional variability between individual cells. These experiments utilized the murine adenocarcinoma 3134 cell line with 200 copies of the MMTV-Ras reporter integrated at a single genomic locus. The MMTV array contains approximately 800-1200 binding sites for the glucocorticoid receptor (GR) and 600 binding sites for the pioneer factor Foxa1. Hormone activation of endogenous GR by dexamethasone treatment resulted in highly variable changes in the RNA FISH intensity (25-300 pixel intensity units) and size (1.25-15 µm), indicative of probabilistic or stochastic mechanisms governing GR and cofactor activation of the MMTV promoter. Exogenous expression of the pioneer factor Foxa1 increased the FISH signal intensity and size as expected for a chromatin remodeler that enhances transcriptional competence through increased chromatin accessibility. In addition, specific analysis of Foxa1-enriched cell sub-populations showed that low and high Foxa1 levels substantially lowered the cell-to-cell variability in the FISH intensity as determined by a noise calculation termed the % coefficient of variation. These results suggest that an additional function of the pioneer factor Foxa1 may be to decrease transcriptional noise.

Multiple modes of chromatin remodeling by Forkhead box proteins.

Forkhead box (FOX) proteins represent a large family of transcriptional regulators unified by their DNA binding domain (DBD) known as a 'forkhead' or 'winged helix' domain. Over 40 FOX genes have been identified in the mammalian genome. FOX proteins share significant sequence similarities in the DBD which allow them to bind to a consensus DNA response element. However, their modes of action are quite diverse as they regulate gene expression by acting as pioneer factors, transcription factors, or both. This review focuses on the mechanisms of chromatin remodeling with an emphasis on three sub-classes-FOXA, FOXO, and FOXP members. FOXA proteins serve as pioneer factors to open up local chromatin structure and thereby increase accessibility of chromatin to factors regulating transcription. FOXP proteins, in contrast, function as classic transcription factors to recruit a variety of chromatin modifying enzymes to regulate gene expression. FOXO proteins represent a hybrid subclass having dual roles as pioneering factors and transcription factors. A subset of FOX proteins interacts with condensed mitotic chromatin and may function as 'bookmarking' agents to maintain transcriptional competence at specific genomic sites. The overall diversity in chromatin remodeling function by FOX proteins is related to unique structural motifs present within the DBD flanking regions that govern selective interactions with core histones and/or chromatin coregulatory proteins. This article is part of a Special Issue entitled: Chromatin in time and space.

Histone deacetylase 1 (HDAC1) participates in the down-regulation of corticotropin releasing hormone gene (crh) expression.

The paraventricular nucleus of the hypothalamus (PVH) plays a central role in regulating the hypothalamic-pituitary-adrenal (HPA) axis. Medial parvocellular neurons of the PVH (mpPVH) integrate sensory and humoral inputs to maintain homeostasis. Humoral inputs include glucocorticoids secreted by the adrenals, which down-regulate HPA activation. A primary glucocorticoid target is the population of mpPVH neurons that synthesize and secrete corticotropin-releasing factors, the most potent of which is corticotropin-releasing hormone (CRH). Although CRH gene (crh) expression is known to be down-regulated by glucocorticoids, the mechanisms by which this process occurs are still poorly understood. To begin this study we postulated that glucocorticoid repression of crh involves HDAC recruitment to the region of the crh proximal promoter. To evaluate this hypothesis, we treated hypothalamic cells that express CRH with the HDAC inhibitor trichostatin A (TSA). As predicted, treatment with TSA led to increased CRH mRNA levels and crh promoter activity. Although co-treatment with Dex (10(-7)M) reduced the TSA effect on mRNA levels, it failed to reduce promoter activity; however co-transfection of HDAC1 but not 3 restored Dex inhibition. A distinction between HDAC1 and 3 was also apparent with respect to crh promoter occupancy. Dex led to increased HDAC1 but not HDAC3 occupancy. In vivo studies revealed that CRH-immunoreactive (-ir) neurons contained HDAC1- and HDAC3-ir. Collectively, these data point to a role for HDAC1 in the physiologic regulation of crh.

TDP-43 is a transcriptional repressor: the testis-specific mouse acrv1 gene is a TDP-43 target in vivo.

TDP-43 is an evolutionarily conserved ubiquitously expressed DNA/RNA-binding protein. Although recent studies have shown its association with a variety of neurodegenerative disorders, the function of TDP-43 remains poorly understood. Here we address TDP-43 function using spermatogenesis as a model system. We previously showed that TDP-43 binds to the testis-specific mouse acrv1 gene promoter in vitro via two GTGTGT-motifs and that mutation of these motifs led to premature transcription in spermatocytes of an otherwise round spermatid-specific promoter. The present study tested the hypothesis that TDP-43 represses acrv1 gene transcription in spermatocytes. Plasmid chromatin immunoprecipitation demonstrated that TDP-43 binds to the acrv1 promoter through GTGTGT motifs in vivo. Reporter gene assays showed that TDP-43 represses acrv1 core promoter-driven transcription via the N-terminal RRM1 domain in a histone deacetylase-independent manner. Consistent with repressor role, ChIP on physiologically isolated germ cells confirmed that TDP-43 occupies the endogenous acrv1 promoter in spermatocytes. Surprisingly, however, TDP-43 remains at the promoter in round spermatids, which express acrv1 mRNA. We show that RNA binding-defective TDP-43, but not splice variant isoforms, relieve repressor function. Transitioning from repressive to active histone marks has little effect on TDP-43 occupancy. Finally, we found that RNA polymerase II is recruited but paused at the acrv1 promoter in spermatocytes. Because mutation of TDP-43 sites caused premature transcription in spermatocytes in vivo, TDP-43 may be involved in pausing RNAPII at the acrv1 promoter in spermatocytes. Overall, our study shows that TDP-43 is a transcriptional repressor and that it regulates spatiotemporal expression of the acrv1 gene during spermatogenesis.

Multiple congenital oral granular cell tumours in a newborn black female: a case report.

INTRODUCTION: Congenital oral granular cell tumour of the newborn is an uncommon benign tumour of uncertain origin. The typical clinical appearance is of a single nodule occurring on the anterior maxillary ridge. In 10% of cases there are multiple lesions. The occurrence of congenital epulis in non-Caucasians is rare. CASE PRESENTATION: Two firm pedunculated nodular lesions were noticed in the mouth of a 3-day-old black female: one on the anterior maxillary ridge and the other further posteriorly in the midline of the palate. Both lesions were excised when the baby was nine days old. Microscopic examination of the lesions showed densely packed round to oval cells with abundant granular eosinophilic cytoplasm and uniform nuclei. The diagnosis was congenital granular cell tumour. CONCLUSION: Congenital oral granular cell tumour occurs almost exclusively in Caucasian newborns but also rarely in black infants. The parents should be assured of the benign nature and the simple treatment of the condition.

Estradiol regulates corticotropin-releasing hormone gene (crh) expression in a rapid and phasic manner that parallels estrogen receptor-alpha and -beta recruitment to a 3',5'-cyclic adenosine 5'-monophosphate regulatory region of the proximal crh promoter.

In the central nervous system, CRH regulates several affective states. Dysregulation of neuronal crh expression in the paraventricular nucleus of the hypothalamus correlates with some forms of depression, and amygdalar crh expression may modulate levels of anxiety. Because estrogens modulate these states, we sought to determine 17beta-estradiol (E2) effects on crh expression. CRH mRNA levels were measured in the AR-5 amygdaloid cell line by RT-PCR analysis. They increased by 1 min of E2 treatment, suggesting that crh behaves as an immediate-early gene. After peaking at 3 min, CRH mRNA returned to basal levels and then increased by 60 min. To dissect some of the molecular mechanisms underlying these events, we measured occupancy of the crh promoter by estrogen receptors (ERs) and coactivators, using chromatin immunoprecipitation. Because this promoter does not contain palindromic estrogen response elements, we targeted the region of a cAMP regulatory element (CRE), implicated in crh regulation. The temporal pattern of the mRNA response was mimicked by recruitment of ERalpha and -beta, phospho-CRE-binding protein, coactivators steroid receptor coactivator-1 and CRE-binding protein-binding protein (CBP), and an increase in histone 3 and 4 acetylation. Lastly, ERalpha and -beta loading were temporally dissociated, peaking at 1 and 3 min, respectively. The ER peaks were associated with coactivators and acetylation patterns. ERalpha associated with phospho-CRE-binding protein, CBP, steroid receptor coactivator-1, and increased acetylated histone 3. ERbeta associated with CBP and increased acetylated histone 4. The tight temporal correlation between E2-induced CRH mRNA levels and promoter occupancy by ERs strongly suggest that E2 regulates crh expression through an ERalpha- and/or ERbeta-CRE alternate pathway.