Aromatase P450 gene expression in human adipose tissue. Role of a Jak/STAT pathway in regulation of the adipose-specific promoter

Demographic and physiological signals of reproductive events in humpback whales on a southwest pacific breeding ground

The field of marine mammal conservation has dramatically benefited from the rapid advancement of methods to assess the reproductive physiology of individuals and populations from steroid hormones isolated from minimally invasive skin-blubber biopsy samples. Historically, this vital information was only available from complete anatomical and physiological investigations of samples collected during commercial or indigenous whaling. Humpback whales (Megaptera novaeangliae) are a migratory, cosmopolitan species that reproduce in warm, low-latitude breeding grounds. New Caledonia is seasonally visited by a small breeding sub-stock of humpback whales, forming part of the endangered Oceania subpopulation. To better understand the demographic and seasonal patterns of reproductive physiology in humpback whales, we quantified baseline measurements of reproductive hormones (progesterone-P4, testosterone-T and 17β-estradiol-E2) using an extensive archive of skin-blubber biopsy samples collected from female humpback whales in New Caledonia waters between 2016 and 2019 (n = 194). We observed significant differences in the P4, T and E2 concentrations across different demographic groups of female humpback whales, and we described some of the first evidence of the endocrine patterns of estrous in live free-ranging baleen whales. This study is fundamental in its methodological approach to a wild species that has a global distribution, with seasonally distinct life histories. This information will assist in monitoring, managing and conserving this population as global ecological changes continue to occur unhindered.

Update on Adipose Tissue and Cancer

Adipose tissue is the largest endocrine organ and an accepted contributor to overall energy homeostasis. There is strong evidence linking increased adiposity to the development of 13 types of cancer. With increased adiposity comes metabolic dysfunction and insulin resistance, and increased systemic insulin and glucose support the growth of many cancers, including those of the colon and endometrium. There is also an important direct crosstalk between adipose tissue and various organs. For instance, the healthy development and function of the mammary gland, as well as the development, growth, and progression of breast cancer, are heavily impacted by the breast adipose tissue in which breast epithelial cells are embedded. Cells of the adipose tissue are responsive to external stimuli, including overfeeding, leading to remodeling and important changes in the secretion of factors known to drive the development and growth of cancers. Loss of factors like adiponectin and increased production of leptin, endotrophin, steroid hormones, and inflammatory mediators have been determined to be important mediators of the obesity-cancer link. Obesity is also associated with a structural remodeling of the adipose tissue, including increased localized fibrosis and disrupted angiogenesis that contribute to the development and progression of cancers. Furthermore, tumor cells feed off the adipose tissue, where increased lipolysis within adipocytes leads to the release of fatty acids and stromal cell aerobic glycolysis leading to the increased production of lactate. Both have been hypothesized to support the higher energetic demands of cancer cells. Here, we aim to provide an update on the state of the literature revolving around the role of the adipose tissue in cancer initiation and progression.

Role and mechanism of the p-JAK2/p-STAT3 signaling pathway in follicular development in PCOS rats

OBJECTIVE

To identify the association between the phosphorylated Janus kinase 2/phosphorylated signal transducer and activator of transcription (p-JAK2/p-STAT3) signaling pathway and follicular development in polycystic ovary syndrome (PCOS) rats, and explore the underlying mechanism. To evaluate the role of exogenous JAK2 inhibitor AG490 in the model and the associations among luteinizing hormone/choriogonadotropin receptor (LHCGR), follicle-stimulating hormone receptor (FSHR), cytochrome P450 17α (CYP17a), cytochrome P450 19 (CYP19), and PCOS.

RESULTS

Rat models of PCOS was established. PCOS rats were intraperitoneally treated with double-distilled water (ddH2O)/DMSO/AG490. The rate of ovarian morphological recovery in the AG490 group was significantly higher compared with the DMSO group (83.3 % vs 9.1 %, X² = 12.68, P < 0.001). Moreover, the short in the time the estrous cycle was resumed in the AG490 group (hazard ratio = 16.32, P < 0.001) compared with the DMSO group. Compared with the controls, p-JAK2, p-STAT3, LHCGR, and CYP17a expression levels were increased whereas that of FSHR and CYP19 were decreased in the ovaries of PCOS rats. However, an opposite trend was observed after treatment with AG490. Software prediction revealed that the p-STAT3 bound to the promoter regions of LHCGR, FSHR, CYP17a, and CYP19 genes. This finding was confirmed by results of correlation analysis (R = 0.834, -0.836, 0.875 and -0.712, respectively, all P < 0.001).

CONCLUSION

This study demonstrated that the p-JAK2/p-STAT3 signaling pathway was involved in follicular development in PCOS rats by upregulating LHCGR and CYP17a expression, and downregulating that of FSHR and CYP19. AG490 treatment exerted beneficial effects. LHCGR, FSHR, CYP17a, and CYP19 are candidate genes associated with follicular development in PCOS rats.

Gut and Endometrial Microbiome Dysbiosis: A New Emergent Risk Factor for Endometrial Cancer

Endometrial cancer is one of the most common gynaecological malignancies worldwide. Histologically, two types of endometrial cancer with morphological and molecular differences and also therapeutic implications have been identified. Type I endometrial cancer has an endometrioid morphology and is estrogen-dependent, while Type II appears with non-endometrioid differentiation and follows an estrogen-unrelated pathway. Understanding the molecular biology and genetics of endometrial cancer is crucial for its prognosis and the development of novel therapies for its treatment. However, until now, scant attention has been paid to environmental components like the microbiome. Recently, due to emerging evidence that the uterus is not a sterile cavity, some studies have begun to investigate the composition of the endometrial microbiome and its role in endometrial cancer. In this review, we summarize the current state of this line of investigation, focusing on the relationship between gut and endometrial microbiome and inflammation, estrogen metabolism, and different endometrial cancer therapies.

Genomic Structure of the Porcine CYP19 Locus and Expression of the CYP19A3 Paralog

Proper, tissue-specific regulation of CYP19, the gene encoding aromatase, the key enzyme of estrogen synthesis, is essential for reproductive processes. Here, we analyzed transcriptional regulation of the porcine CYP19 in female and male gonads and brain by 5'RACE and RT-PCR and comprehensively mapped the pig CYP19 locus by in silico analysis. Our data revealed that the complete locus, including three paralogous copies, CYP19A1, CYP19A2 and CYP19A3, spans approximately 330 kb of the porcine chromosome 1. The locus also harbors the first exon of the Gliomedin gene (GLDN) in reverse orientation. Only transcripts of the CYP19A3 paralog were substantially expressed in gonads and hypothalamus. We identified CYP19A3-associated untranslated exons approximately 160 kb and 50 kb distal from the first codon. The 5´ untranslated regions of transcripts were derived from either a proximal or from one of these distal untranslated exons. Transcripts including only untranslated exons could be amplified from testis, thus suggesting long non-coding transcripts. The data revealed an additional layer of complexity in the regulation of the porcine CYP19 locus. Tissue-specific expression is not only achieved by tissue- and stage-specific expression of the three different CYP19 paralogs, but also by directing the expression of CYP19A3 from different, proximal and distal promoter regions.

The NF-[Formula: see text]B Signaling and Wnt/[Formula: see text]-catenin Signaling in MCF-7 Breast Cancer Cells in Response to Bioactive Components from Mushroom Antrodia Camphorata

Breast cancer is the leading cancer, accounting for approximately 15% cancer deaths in women worldwide. This study investigated the anti-inflammation and anticancer properties of two bioactive components from Antrodia camphorata(AC), a rare medicinal mushroom natively grown in Taiwan and commonly used in Chinese traditional medicine. The anti-inflammatory and antitumorigenic functions of Antroquinonol (AQ) and 4-Acetylantroquinonol B (4-AAQB) from AC were examined on breast cancer cell line MCF-7 with/without TNF-[Formula: see text] stimulation. Among nine inflammatory mediators (IL6, IL10, IL1[Formula: see text], IFN[Formula: see text], PTGS2, TGF[Formula: see text]1, TNF-[Formula: see text], CCL2 andCSF1) examined, AQ inhibited two of them (IL-10 and PTGS2), while 4-AAQB inhibited three of them (IL-10, PTGS2 andTNF-[Formula: see text] ([Formula: see text]¡ 0.05). TNF-[Formula: see text] stimulated expressions of five mediators (IL6, IL10, IFN[Formula: see text], PTGS2, and CCL2), and AQ and 4-AAQB inhibited IL6 elevation ([Formula: see text]¡ 0.05). Both components inhibited aromatase expression with/without TNF-[Formula: see text] stimulation, with 4-AAQB to be more effective ([Formula: see text]¡ 0.05). For immune checkpoint CD47, both components inhibited CD47 expression ([Formula: see text]¡ 0.05), but it did not respond to TNF-[Formula: see text] stimulation. For Wnt/[Formula: see text]- catenin signaling downstream genes (CCND1, C-MYC and AXIN2), both components have significant or marginal inhibitory effect on C-MYC in the condition with/without TNF-[Formula: see text] stimulation. The luciferase assay demonstrated that both components exhibited inhibitory effect on NF-[Formula: see text]B signaling and Wnt/[Formula: see text]-catenin signaling in the condition without TNF-[Formula: see text] stimulation. In conclusion, our results displayed an overall pattern that AQ and 4-AAQB possess potential anti-inflammatory and antitumorigenic functions in MCF-7 breast cancer cells and warranted further in vivo pre-clinical and clinical studies to explore their anticancer properties.

Adipose Tissue and Endocrine-Disrupting Chemicals: Does Sex Matter?

Obesity and metabolic-related diseases, among which diabetes, are prominent public health challenges of the 21st century. It is now well acknowledged that pollutants are a part of the equation, especially endocrine-disrupting chemicals (EDCs) that interfere with the hormonal aspect. The aim of the review is to focus on adipose tissue, a central regulator of energy balance and metabolic homeostasis, and to highlight the significant differences in the endocrine and metabolic aspects of adipose tissue between males and females which likely underlie the differences of the response to exposure to EDCs between the sexes. Moreover, the study also presents an overview of several mechanisms of action by which pollutants could cause adipose tissue dysfunction. Indeed, a better understanding of the mechanism by which environmental chemicals target adipose tissue and cause metabolic disturbances, and how these mechanisms interact and sex specificities are essential for developing mitigating and sex-specific strategies against metabolic diseases of chemical origin. In particular, considering that a scenario without pollutant exposure is not a realistic option in our current societies, attenuating the deleterious effects of exposure to pollutants by acting on the gut-adipose tissue axis may constitute a new direction of research.

SHBG and total testosterone levels in men with adult onset hypogonadism: what are we overlooking?

Background

Adult onset male hypogonadism (AOH) is a common clinical condition whose diagnosis and management are controversial, and is often characterized by a low level of SHBG, but our understanding of why testosterone levels are low when SHBG is low is incomplete.

Methods

This retrospective chart review was performed to compare the relationship between SHBG and testosterone in the plasma of men presenting for evaluation of AOH with a cohort of men treated chronically with transdermal testosterone.

Results

The level of SHBG was < 30 nmol/L in 73% of men who presented for evaluation of AOH, and was inversely proportional to BMI in both the untreated and the testosterone-treated men. As in previous populations, the level of SHBG was highly positively correlated (r = 0.71, p < 0.01) with the total testosterone level in untreated men presenting for evaluation of AOH, but no relationship was found between the level of SHBG and total testosterone among men who were being treated with a transdermal testosterone preparation.

Conclusions

These findings further support the idea that SHBG regulates testicular negative feedback either directly or by modulating the entry of testosterone or estradiol into cells in the hypothalamus and/or pituitary to control gonadotropin synthesis and secretion which explains in part the low testosterone levels in men with AOH.

Trial registration

Not applicable.

Temporal Acute Serum Estradiol and Tumor Necrosis Factor-α Associations and Risk of Death after Severe Traumatic Brain Injury

Severe traumatic brain injury (TBI) activates a robust systemic response that involves inflammatory and other factors, including estradiol (E2), associated with increased deaths. Tumor necrosis factor-alpha (TNFα) is a significant mediator of systemic shock, and it is an extra-gonadal transcription factor for E2 production. The study objectives were to test the hypotheses: (1) a positive feedback relationship exists between acute serum TNFα and E2; and (2) acute concentrations of E2 and TNFα are prognostic indicators of death after severe TBI. This prospective cohort study included N = 157 adults with severe TBI. Serum samples were collected for the first five days post-injury. The TNFα and E2 levels were averaged into two time epochs: first 72 h (T1) and second 72 h post-injury (T2). A cross-lag panel analysis conducted between T1 and T2 TNFα and E2 levels showed significant cross-lag effects: T1 TNFα and T1 E2 were related to T2 E2 and T2 TNFα, respectively. Cox proportional hazards multi variable regression models determined that increases in T1 E2 (hazard ratio [HR] = 1.79, 95% confidence interval [CI]: 1.15, 2.81), but not T2 E2 (HR = 0.91, 95% CI: 0.56, 1.47), were associated with increased risk of death. Increased T2 TNFα (HR = 2.47, 95% CI: 1.35, 4.53), and T1 TNFα (HR = 1.47, 95% CI: 0.99, 2.19), to a lesser degree, were associated with increased risk of death. Relationships of death with T2 TNFα and T1 E2 were mediated partially by cardiovascular, hepatic, and renal dysfunction. Both E2 and TNFα are systemic, reciprocally related biomarkers that may be indicative of systemic compromise and increased risk of death after severe TBI.

Estrogens and Glucocorticoids in Mammary Adipose Tissue: Relationships with Body Mass Index and Breast Cancer Features

CONTEXT

Adipose tissue is an important site for extragonadal steroid hormone biosynthesis through the expression and activity of P450 aromatase, 11β-hydroxysteroid dehydrogenase (HSD) 1, and 17β-HSDs. The contribution of steroid hormones produced by adjacent adipose tissue for the progression and survival of breast tumors is unknown.

OBJECTIVE

To quantify estrogens (estradiol, estrone) and glucocorticoids (cortisol, cortisone) in breast adipose tissue from both healthy and diseased women and their relationships with adiposity indices and breast cancer prognostic markers.

DESIGN AND SETTING

Breast adipose tissue was collected at time of surgery.

PATIENTS

Pre- and postmenopausal women undergoing partial mastectomy for treatment of breast cancer (n = 17) or reduction mammoplasty (n = 6) were studied.

INTERVENTIONS

Relative estrogen and glucocorticoid amounts were determined by liquid chromatography tandem mass spectrometry.

RESULTS

The targeted steroids were reliably detected and quantified in mammary adipose tissues. Women with ER+/PR+ tumor had higher relative estradiol amount than women with ER-/PR- tumor (P < .05). The ratio of estradiol-to-estrone was higher in lean women than in women with a body mass index (BMI) ≥ 25 kg/m2 (P < .05). Mixed-model analyses showed that estradiol, cortisone, and cortisol were negatively associated with tumor size (P < .05). Relationships between glucocorticoids and tumor size remained significant after adjustment for BMI. The cortisol-to-cortisone ratio was negatively associated with tumor stage (P < .05) independently of BMI.

CONCLUSIONS

We reliably quantified estrogens and glucocorticoids in breast adipose tissue from healthy women and women suffering from breast cancer. Our findings suggest that smaller breast tumors are associated with higher relative amounts of estradiol and cortisol in adipose tissue.

Simultaneous quantification of estrogens and glucocorticoids in human adipose tissue by liquid-chromatography-tandem mass spectrometry

The presence of estrogens, androgens and glucocorticoids as well as their receptors and steroid converting enzymes in adipose tissue has been established. Their contribution to diseases such as obesity, diabetes and hormone-dependent cancers is an active area of research. Our objective was to develop a LC-MS/MS method to quantify bioactive estrogens and glucocorticoids simultaneously in human adipose tissue. Estrogens and glucocorticoids were extracted from adipose tissue samples using solid-phase extraction. Estrogens were derivatized using 1-(2,4-dinitro-5-fluorophenyl)-4-methylpiperazine (PPZ) and methyl iodide to generate a permanently charged molecule (MPPZ). Steroids were separated and quantified by LC-MS/MS. The limit of quantitation for the steroids was between 15 and 100 pg per sample. Accuracy and precision were acceptable (<20%). Using this method, estradiol, estrone, cortisone and cortisol were quantified in adipose tissue from women with and without breast cancer. This novel assay of estrogens and glucocorticoids by LC-MS/MS coupled with derivatization allowed simultaneous quantification of a panel of steroids in human adipose tissue across the endogenous range of concentrations encountered in health and disease.

Estrogens and breast cancer: Mechanisms involved in obesity-related development, growth and progression

Obesity is a risk factor for estrogen receptor-positive (ER+) breast cancer after menopause. The pro-proliferative effects of estrogens are well characterized and there is a growing body of evidence to also suggest an important role in tumorigenesis. Importantly, obesity not only increases the risk of breast cancer, but it also increases the risk of recurrence and cancer-associated death. Aromatase is the rate-limiting enzyme in estrogen biosynthesis and its expression in breast adipose stromal cells is hypothesized to drive the growth of breast tumors and confer resistance to endocrine therapy in obese postmenopausal women. The molecular regulation of aromatase has been characterized in response to many obesity-related molecules, including inflammatory mediators and adipokines. This review is aimed at providing an overview of our current knowledge in relation to the regulation of estrogens in adipose tissue and their role in driving breast tumor development, growth and progression.

The Emerging Roles of Steroid Hormone Receptors in Ductal Carcinoma in Situ (DCIS) of the Breast

Ductal carcinoma in situ (DCIS) is a non-obligate precursor to most types of invasive breast cancer (IBC). Although it is estimated only one third of untreated patients with DCIS will progress to IBC, standard of care for treatment is surgery and radiation. This therapeutic approach combined with a lack of reliable biomarker panels to predict DCIS progression is a major clinical problem. DCIS shares the same molecular subtypes as IBC including estrogen receptor (ER) and progesterone receptor (PR) positive luminal subtypes, which encompass the majority (60-70%) of DCIS. Compared to the established roles of ER and PR in luminal IBC, much less is known about the roles and mechanism of action of estrogen (E2) and progesterone (P4) and their cognate receptors in the development and progression of DCIS. This is an underexplored area of research due in part to a paucity of suitable experimental models of ER+/PR + DCIS. This review summarizes information from clinical and observational studies on steroid hormones as breast cancer risk factors and ER and PR as biomarkers in DCIS. Lastly, we discuss emerging experimental models of ER+/PR+ DCIS.

Estradiol to Androstenedione Ratios Moderate the Relationship between Neurological Injury Severity and Mortality Risk after Severe Traumatic Brain Injury

Early declines in gonadotropin production, despite elevated serum estradiol, among some individuals with severe traumatic brain injury (TBI) suggests amplified systemic aromatization occurs post-injury. Our previous work identifies estradiol (E2) as a potent mortality marker. Androstenedione (A), a metabolic precursor to E2, estrone (E1), and testosterone (T), is a steroid hormone substrate for aromatization that has not been explored previously as a biomarker in TBI. Here, we evaluated serum A, E1, T, and E2 values for 82 subjects with severe TBI. Daily hormone values were calculated, and E2:A and E1:T ratios were generated and then averaged for days 0-3 post-injury. After data inspection, mean E2:A values were categorized as above (high aromatization) and below (low aromatization) the 50th percentile for 30-day mortality assessment using Kaplan-Meier survival analysis and a multivariable Cox proportional hazard model adjusting for age, and Glasgow Coma Scale (GCS) to predict 30-day mortality status. Daily serum T, E1, and E2 were graphed by E2:A category. Serum E1 and E2 significantly differed over time (p < 0.05); the high aromatization group had elevated levels and a significantly lower probability of survival within the first 30 days (p = 0.0274). Multivariable Cox regression showed a significant E2:A*GCS interaction (p = 0.0129), wherein GCS predicted mortality only among those in the low aromatization group. E2:A may be a useful mortality biomarker representing enhanced aromatization after TBI. E2:A ratios may represent non-neurological organ dysfunction after TBI and may be useful in defining injury subgroups in which GCS has variable capacity to serve as an accurate early prognostic marker.

Systemic Estrone Production and Injury-Induced Sex Hormone Steroidogenesis after Severe Traumatic Brain Injury: A Prognostic Indicator of Traumatic Brain Injury-Related Mortality

Extensive pre-clinical studies suggest that sex steroids are neuroprotective in experimental traumatic brain injury (TBI). However, clinical trials involving sex hormone administration have not shown beneficial results, and our observational cohort studies show systemic estradiol (E2) production to be associated with adverse outcomes. Systemic E2 is produced via aromatization of testosterone (T) or reduction of estrone (E1). E1, also produced via aromatization of androstenedione (Andro) and is a marker of T-independent E2 production. We hypothesized that E1 would be (1) associated with TBI-related mortality, (2) the primary intermediate for E2 production, and (3) associated with adipose tissue-specific aromatase transcription. We assessed 100 subjects with severe TBI and 8 healthy controls. Serum levels were measured on days 0-3 post-TBI for key steroidogenic precursors (progesterone), aromatase pathway intermediates (E1, E2, T, Andro), and the adipose tissue-specific aromatase transcription factors cortisol, tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6). E1 was elevated after TBI versus controls. High E1 was associated with higher progesterone, cortisol, and IL-6 (p < 0.05). Multivariable logistic regression demonstrated that those in the highest E1 tertile had increased odds for mortality (adjusted OR = 5.656, 95% CI = 1.102-29.045, p = 0.038). Structural equation models show that early serum E2 production is largely T independent, occurring predominantly through E1 metabolism. Acute serum E1 functions as a mortality marker for TBI through aromatase-dependent E1 production and T-independent E2 production. Further work should evaluate risk factors for high E2 production and how systemic E2 and its key intermediate E1 contribute to the extracerebral consequences of severe TBI.

Signals from the Adipose Microenvironment and the Obesity-Cancer Link-A Systematic Review

Obesity and its associated metabolic dysregulation are established risk factors for many cancers. However, the biologic mechanisms underlying this relationship remain incompletely understood. Given the rising rates of both obesity and cancer worldwide, and the challenges for many people to lose excess adipose tissue, a systematic approach to identify potential molecular and metabolic targets is needed to develop effective mechanism-based strategies for the prevention and control of obesity-driven cancer. Epidemiologic, clinical, and preclinical data suggest that within the growth-promoting, proinflammatory microenvironment accompanying obesity, crosstalk between adipose tissue (comprised of adipocytes, macrophages and other cells) and cancer-prone cells may occur via obesity-associated hormones, cytokines, and other mediators that have been linked to increased cancer risk and/or progression. We report here a systematic review on the direct "crosstalk" between adipose tissue and carcinomas in humans. We identified 4,641 articles with n = 20 human clinical studies, which are summarized as: (i) breast (n = 7); (ii) colorectal (n = 4); (iii) esophageal (n = 2); (iv) esophageal/colorectal (n = 1); (v) endometrial (n = 1); (vi) prostate (n = 4); and (vii) ear-nose-throat (ENT) cancer (n = 1). Findings from these clinical studies reinforce preclinical data and suggest organ-dependent crosstalk between adipose tissue and carcinomas via VEGF, IL6, TNFα, and other mechanisms. Moreover, visceral white adipose tissue plays a more central role, as it is more bioenergetically active and is associated with a more procancer secretome than subcutaneous adipose tissue. Efforts to eavesdrop and ultimately interfere with this cancer-enhancing crosstalk may lead to new targets and strategies for decreasing the burden of obesity-related cancers. Cancer Prev Res; 10(9); 494-506. ©2017 AACR.

Evaluation of complete blood count parameters to predict endometrial cancer

BACKGROUND

Complete blood count parameters have been introduced to be diagnostic biomarkers for many cancer-related diseases associated with inflammatory process. The aim of our study was to detect whether there is any relationship between benign or malignant endometrial pathologies and complete blood count parameters.

METHODS

Four hundred and sixteen patients with a complaint of abnormal uterine bleeding who admitted to Zeynep Kamil Women and Children's Health Training and Research hospital between 2013 and 2016 and undergoing endometrial biopsy were included in the study. The patients were evaluated in three groups as follows: endometrial carcinoma (n: 97), endometrial hyperplasia (n: 135), and healthy control (n: 184) groups. All patients had a complete blood count on the day of biopsy or within the week of the biopsy, and the presence of a relationship between complete blood count parameters and benign or malignant endometrial disease was investigated.

RESULTS

Mean corpuscular volume measurements were found to be significantly higher in endometrial carcinoma (P = .018) and endometrial hyperplasia (P = .001) groups compared to the control group. While red cell distribution width measurements were found to be significantly lower in patients with endometrial carcinoma group compared to other groups (P < .01); the area under curve obtained for MPV is 58.7% to determine endometrial carcinoma.

CONCLUSION

Mean corpuscular volume and red cell distribution width are bio-markers that we can use as the predictive marker in patients with endometrial carcinoma and which are cheap, repeatable, and readily obtainable from complete blood count panels and promising.

Profile of CYP19A1 mRNA expression and aromatase activity during syncytialization of primary human villous trophoblast cells at term

Estrogen production by the human villous trophoblast is dependent on the biosynthetic enzyme aromatase (CYP19; CYP19A1) and is crucial for successful placental development and pregnancy outcome. Using villous cytotrophoblast cells (vCTs) freshly isolated from normal term placenta, we characterized the promoter-specific expression of CYP19A1 mRNA (derived from promoters I.1, I.4, I.8 or total transcript) and aromatase activity during villous trophoblast syncytialization. CYP19A1 mRNA levels and aromatase activity in vCTs reached a maximum after about 48 h of culture. The cAMP inducer forskolin (10 μM) and protein kinase C stimulant phorbol myristate acetate (1 μM) increased CYP19A1 mRNA levels by 1.8- and 1.6-fold, respectively, as well as inducing aromatase catalytic activity. Dexamethasone (100 nM) and vascular endothelial growth factor (5 ng/mL) decreased CYP19A1 mRNA levels, while having no effect on aromatase activity. Our results emphasize the importance of not solely studying CYP19A1 regulation and function at the mRNA level but also considering posttranslational mechanisms that alter the final catalytic activity of aromatase.

IL-10 suppresses TNF-α-induced expression of human aromatase gene in mammary adipose tissue

White adipose tissue inflammation is linked with increased aromatase gene expression and estrogen production, a major risk factor for breast cancer in obese postmenopausal women. TNF-α, a proinflammatory cytokine, is a key driver of aromatase promoter I.4-mediated expression in adipose tissue. In this study, we have shown that IL-10, an anti-inflammatory cytokine, suppressed both TNF-α-stimulated human aromatase reporter-luciferase (hARO-Luc) expression in mouse bone marrow mesenchymal stromal cells and aromatase gene expression in human breast adipose stromal cells (ASCs). IL-10 blocked TNF-α-stimulated ERK1/2 activation in ASCs, suggesting an inhibitory effect through the MAPK signaling pathway. The links among obesity, IL-10, and aromatase were confirmed in ovariectomized (OVX) hARO-Luc mice, where increased adiposity was associated with upregulation of aromatase reporter activity and reduced IL-10 level in the mammary fat pad. OVX mice also exhibited changes in gut microbiota, similar to that in obese women, indicating altered immune function. In summary, our results suggest that increased adiposity, induced by the lack of ovarian hormones, results in enhanced expression of aromatase in mammary adipose tissue, mediated by reduction in local IL-10. These findings may bring new insights into the mechanisms involved in the development of postmenopausal breast cancer, as well as novel approaches for prevention.-Martínez-Chacón, G., Brown, K. A., Docanto, M. M., Kumar, H., Salminen, S., Saarinen, N., Mäkelä, S. IL-10 suppresses TNF-α-induced expression of human aromatase gene in mammary adipose tissue.

SGBS cells as a model of human adipocyte browning: A comprehensive comparative study with primary human white subcutaneous adipocytes

The Simpson Golabi Behmel Syndrome (SGBS) pre-adipocyte cell strain is widely considered to be a representative in vitro model of human white pre-adipocytes. A recent study suggested that SGBS adipocytes exhibit an unexpected transient brown phenotype. Here, we comprehensively examined key differences between SGBS adipocytes and primary human white subcutaneous (PHWSC) adipocytes. RNA-Seq analysis revealed that extracellular matrix (ECM)-receptor interaction and metabolic pathways were the top two KEGG pathways significantly enriched in SGBS adipocytes, which included positively enriched mitochondrial respiration and oxidation pathways. Compared to PHWSC adipocytes, SGBS adipocytes showed not only greater induction of adipogenic gene expression during differentiation but also increased levels of UCP1 mRNA and protein expression. Functionally, SGBS adipocytes displayed higher ISO-induced basal leak respiration and overall oxygen consumption rate, along with increased triglyceride accumulation and insulin-stimulated glucose uptake. In conclusion, we confirmed that SGBS adipocytes, which are considered of white adipose tissue origin can shift towards a brown/beige adipocyte phenotype. These differences indicate SGBS cells may help to identify mechanisms leading to browning, and inform our understanding for the use of SGBS vis-à-vis primary human subcutaneous adipocytes as a human white adipocyte model, guiding the selection of appropriate cell models in future metabolic research.

Steroidogenic enzyme expression in estrogen production in the goat gastrointestinal (GI) tract and the effect of castration

Extragonadal tissues are known to produce estrogens. At these sites, the C19 precursor is important for aromatase expression for the production of estrogen. Aromatase expression is tissue-specific and is controlled by hormones. Recent studies have shown that rat gastric parietal cells expressed aromatase. Our first objective was to investigate steroidogenic enzyme expression in estrogen biosynthesis; the second objective was to investigate which site(s) of the GI tract expressed steroidogenic enzymes; and the third objective was to assess the effects of castration on steroidogenic enzyme expression. CYP19A1, 17β-HSD3, CYP17A1, 3β-HSD and P450scc were quantified in the GI tract by real-time PCR. CYP19A1 was detected mainly in the body and pyloric regions of the abomasum, while we detected weak expression of CYP19A1 in other parts of GI tract. In addition, the expression of 17β-HSD3 and CYP17A1 was detected in abomasum. 3β-HSD expression was observed in duodenum and jejunum, while P450scc was not detectable in any part of GI tract. Immunohistochemical results showed immunolocalization of aromatase in parietal cells. Aromatase expression was observed to increase after castration. Furthermore, immunohistochemical results demonstrated that parietal cells also produced luteinizing hormone receptor (LHR). These results indicate steroidogenic enzymes required for the biosynthesis of estrogen were expressed, and the abomasum appeared to be the responsible organ for estrogen biosynthesis in the goat GI tract. In addition, parietal cells were responsible for estrogen production and the expression of LHR. Castration increased aromatase expression in abomasum through LH mediation.

Ghrelin and Breast Cancer: Emerging Roles in Obesity, Estrogen Regulation, and Cancer

Local and systemic factors have been shown to drive the growth of breast cancer cells in postmenopausal obese women, who have increased risk of estrogen receptor-positive breast cancer. Estrogens, produced locally in the breast fat by the enzyme aromatase, have an important role in promoting cancer cell proliferation. Ghrelin, a 28-amino acid peptide hormone, may also influence cancer growth. This peptide is produced in the stomach and acts centrally to regulate appetite and growth hormone release. Circulating levels of ghrelin, and its unacylated form, des-acyl ghrelin, are almost always inversely correlated with obesity, and these peptide hormones have recently been shown to inhibit adipose tissue aromatase expression. Ghrelin and des-acyl ghrelin have also been shown to be produced by some tumor cells and influence tumor growth. The ghrelin/des-acyl ghrelin–cancer axis is complex, one reason being that tumor cells have been shown to express splice variants of ghrelin, and ghrelin and des-acyl ghrelin might act at receptors other than the cognate ghrelin receptor, growth hormone secretagogue receptor 1a, in tumors. Effects of ghrelin and des-acyl ghrelin on energy homeostasis may also affect tumor development and growth. This review will summarize our current understanding of the role of ghrelin and des-acyl ghrelin in hormone-dependent cancers, breast cancer in particular.

Selective Estrogen-Receptor Modulators and Aromatase Inhibitors: Promising New Medical Therapies for Endometriosis?

Endometriosis is an estrogen-dependent disease and estrogen-related pathways are imbalanced in women with endometriosis. One of the key enzymes in estrogen synthesis is aromatase. Inhibiting this pathway at several points is a promising idea for the treatment of endometriosis. The third generation of aromatase inhibitors is becoming more potent in efficacy, with fewer side effects than previous generations, but cotreatment with other hormones is needed to inhibit ovarian stimulation. Other components that promote estrogen synthesis such as COX-2 can also be potentially targeted. Selective estrogen-receptor modulators could also be interesting in view of their tissue-specific effect. However, all these new drugs are still in an early phase of development. At present, it is too early to conclude that aromatase inhibitors, COX-2 inhibitors or selective estrogen-receptor modulators really present any added value compared with the existing drugs that can be used to achieve hormonal suppression in the medical treatment of endometriosis.

Structural and functional characterization of aromatase, estrogen receptor, and their genes in endocrine-responsive and -resistant breast cancer cells

Aromatase and estrogen receptor α (ER) are two key proteins for the proliferation of endocrine-responsive and -resistant breast cancers. Aromatase is an enzyme involved in the conversion of androgen (such as testosterone) to estrogen (such as 17β-estradiol). It is also a very effective therapeutic target for the treatment of endocrine-responsive breast cancer. Comparing endocrine-responsive and -resistant breast cancer, aromatase protein levels do not change significantly. Aromatase activity; however, can be increased via PI3K/Akt/IGFR signaling pathways in endocrine resistant cells. The activity of aromatase has been reported to be modulated by phosphorylation. The ER is an important steroid nuclear receptor in the proliferation of both endocrine-responsive and -resistant cells. Although the mutation or amplification of ER can cause endocrine resistance, it is not commonly found. Some point mutations and translocation events have been characterized and shown to promote estrogen-independent growth. Phosphorylation by cross-talk with growth factor pathways is one of the main mechanisms for ligand-independent activation of ER. Taken together, both ER and aromatase are important in ER-dependent breast cancer and the development of endocrine resistance.

Aromatase expression and regulation in breast and endometrial cancer

Long-term exposure to excess estrogen increases the risk of breast cancer and type 1 endometrial cancer. Most of the estrogen in premenopausal women is synthesized by the ovaries, while extraovarian subcutaneous adipose tissue is the predominant tissue source of estrogen after menopause. Estrogen and its metabolites can cause hyperproliferation and neoplastic transformation of breast and endometrial cells via increased proliferation and DNA damage. Several genetically modified mouse models have been generated to help understand the physiological and pathophysiological roles of aromatase and estrogen in the normal breast and in the development of breast cancers. Aromatase, the key enzyme for estrogen production, is comprised of at least ten partially tissue-selective and alternatively used promoters. These promoters are regulated by distinct signaling pathways to control aromatase expression and estrogen formation via recruitment of various transcription factors to their cis-regulatory elements. A shift in aromatase promoter use from I.4 to I.3/II is responsible for the excess estrogen production seen in fibroblasts surrounding malignant epithelial cells in breast cancers. Targeting these distinct pathways and/or transcription factors to modify aromatase activity may lead to the development of novel therapeutic remedies that inhibit estrogen production in a tissue-specific manner.

Resveratrol for breast cancer prevention and therapy: Preclinical evidence and molecular mechanisms

Globally, breast cancer is the most frequently diagnosed cancer among women. The major unresolved problems with metastatic breast cancer is recurrence after receiving objective response to chemotherapy, drug-induced side effects of first line chemotherapy and delayed response to second line of treatment. Unfortunately, very few options are available as third line treatment. It is clear that under such circumstances there is an urgent need for new and effective drugs. Phytochemicals are among the most promising chemopreventive treatment options for the management of cancer. Resveratrol (3,5,4'-trihydroxy-trans-stilbene), a non-flavonoid polyphenol present in several dietary sources, including grapes, berries, soy beans, pomegranate and peanuts, has been shown to possess a wide range of health benefits through its effect on a plethora of molecular targets.The present review encompasses the role of resveratrol and its natural/synthetic analogue in the light of their efficacy against tumor cell proliferation, metastasis, epigenetic alterations and for induction of apoptosis as well as sensitization toward chemotherapeutic drugs in various in vitro and in vivo models of breast cancer. The roles of resveratrol as a phytoestrogen, an aromatase inhibitor and in stem cell therapy as well as adjuvent treatment are also discussed. This review explores the full potential of resveratrol in breast cancer prevention and treatment with current limitations, challenges and future directions of research.

Weight gain and inflammation regulate aromatase expression in male adipose tissue, as evidenced by reporter gene activity

Obesity and white adipose tissue (WAT) inflammation are associated with enhanced aromatization in women, but little is known about the regulation of aromatase (CYP19A1) gene expression in male WAT. We investigated the impact of weight gain and WAT inflammation on the regulation of CYP19A1 in males, by utilizing the hARO-Luc aromatase reporter mouse model containing a >100-kb 5'-region of the human CYP19A1 gene. We show that hARO-Luc reporter activity is enhanced in WAT of mice with increased adiposity and inflammation. Dexamethasone and TNFα, as well as forskolin and phorbol 12-myristate 13-acetate, upregulate hARO-Luc activity, suggesting the involvement of promoters I.4 and I.3/II. Furthermore, we show that diet enriched with antioxidative plant polyphenols attenuates WAT inflammation and hARO-Luc activity in obese males. In conclusion, our data suggest that obesity-associated WAT inflammation leads to increased peripheral CYP19A1 expression in males, and that polyphenol-enriched diet may have the potential to attenuate excessive aromatization in WAT of obese men.

Fenretinide prevents obesity in aged female mice in association with increased retinoid and estrogen signaling

OBJECTIVE

The synthetic retinoid fenretinide (FEN) inhibits adiposity in male mice fed a high-fat diet (HFD) in association with alterations in retinoic acid (RA) signaling. Young female mice are protected from obesity via estrogen signaling. We, therefore, investigated whether FEN also influences adiposity in aged female mice differing in parity and whether such effects are mediated by retinoid and estrogen signaling.

METHODS

Aged nulliparous and parous female mice were maintained on HFD ± FEN, and adiposity was assessed. Quantitative polymerase chain reaction was performed on white adipose tissue (WAT), liver, and 3T3-L1 adipocytes treated with RA or FEN ± estrogen.

RESULTS

Parous females were more obese than nulliparous mice independent of age. FEN-HFD prevented the HFD-induced increase in adiposity and leptin levels independently of parity. FEN-HFD induced retinoid-responsive genes in WAT and liver. Parous females had reduced expression of hepatic estrogen-responsive genes, but FEN-HFD up-regulated WAT Cyp19a1 and Esr2 in parous mice. Estrogen and RA acted synergistically to increase RA receptor-mediated gene expression in 3T3-L1 adipocytes. FEN increased Cyp19a1 and Esr2, similar to our findings in vivo.

CONCLUSIONS

The prevention of adiposity by FEN in response to HFD in female mice seems to involve increased retinoid signaling in association with induction of local estrogen production and estrogen signaling in WAT.

Obesity-Associated Inflammatory Cytokines and Prostaglandin E2 Stimulate Glucose Transporter mRNA Expression and Glucose Uptake in Primary Human Adipose Stromal Cells

Obesity is associated with chronic low-grade inflammation. This occurs largely as a result of the infiltration of immune cells within the obese adipose, which produce a number of inflammatory factors, including interleukin-6 (IL-6), IL-1β, tumor necrosis factor-α (TNFα), and prostaglandin E(2) (PGE(2)). These factors have previously been shown to affect insulin-mediated glucose uptake in differentiated adipocytes. However, the insulin-independent effect of inflammation on adipocyte precursors, the adipose stromal cells, has not been explored. This study therefore aimed to examine the effect of obesity-associated inflammatory factors on the expression of insulin-independent glucose transporters (GLUT1 and GLUT3) and on the uptake of glucose within adipose stromal cells. Primary human subcutaneous adipose stromal cells were isolated from abdominoplasty, and the effect of inflammatory cytokines (IL-6, IL-1β, and TNFα) and PGE(2) on GLUT mRNA expression and glucose transport was assessed using real-time polymerase chain reaction and radiolabeled deoxyglucose uptake assays, respectively. Results demonstrate that all four inflammatory mediators caused a dose-dependent increase in GLUT1 mRNA expression and glucose uptake. GLUT3 mRNA expression was also upregulated by IL-6 (0.5 ng/mL), TNFα (0.1 and 10 ng/mL), and PGE(2) (0.1 μM). Overall, these results demonstrate that obesity-associated inflammation increases insulin-independent glucose transporter expression and glucose uptake in undifferentiated adipose stromal cells.

Updated survey of the steroid-converting enzymes in human adipose tissues

Over the past decade, adipose tissues have been increasingly known for their endocrine properties, that is, their ability to secrete a number of adipocytokines that may exert local and/or systemic effects. In addition, adipose tissues have long been recognized as significant sites for steroid hormone transformation and action. We hereby provide an updated survey of the many steroid-converting enzymes that may be detected in human adipose tissues, their activities and potential roles. In addition to the now well-established role of aromatase and 11β-hydroxysteroid dehydrogenase (HSD) type 1, many enzymes have been reported in adipocyte cell lines, isolated mature cells and/or preadipocytes. These include 11β-HSD type 2, 17β-HSDs, 3β-HSD, 5α-reductases, sulfatases and glucuronosyltransferases. Some of these enzymes are postulated to bear relevance for adipose tissue physiology and perhaps for the pathophysiology of obesity. This elaborate set of steroid-converting enzymes in the cell types of adipose tissue deserves further scientific attention. Our work on 20α-HSD (AKR1C1), 3α-HSD type 3 (AKR1C2) and 17β-HSD type 5 (AKR1C3) allowed us to clarify the relevance of these enzymes for some aspects of adipose tissue function. For example, down-regulation of AKR1C2 expression in preadipocytes seems to potentiate the inhibitory action of dihydrotestosterone on adipogenesis in this model. Many additional studies are warranted to assess the impact of intra-adipose steroid hormone conversions on adipose tissue functions and chronic conditions such as obesity, diabetes and cancer.

Transcriptional control of local estrogen formation by aromatase in the breast

Aromatase is the critical enzyme that converts androgens to estrogens. It is frequently highly expressed in the tumour bearing breast of women diagnosed with estrogen receptor positive tumours, resulting in dramatically increased local estrogen production to drive tumour progression. Expression of aromatase is regulated primarily at the transcriptional level of its encoding gene CYP19A1, located on chromosome 15 of the human genome. A characteristic feature of CYP19A1 expression is its use of alternative promoters to regulate transcription in a tissue-specific manner. In breast cancer, the increase in aromatase expression is mediated via higher expression of the distal adipose-specific promoter I.4 and a switch to the preferential use of proximal promoters I.3 and II. This results in a net increase of CYP19A1 transcripts in tumour-bearing breast up to 3-4-fold higher than normal breast. Current aromatase inhibitors - whilst efficacious - exhibit significant side effects that reduce patient compliance. Understanding the transcription factors and signalling pathways that control aromatase expression will lead to opportunities to develop breast-specific inhibitors with an improved side-effects profile. This article is part of a Special Issue entitled 'Essential role of DHEA'.

Impact of exogenous gonadotropin stimulation on circulatory and follicular fluid cytokine profiles

Background. The natural cycle is the prototype to which we aspire to emulate in assisted reproduction techniques. Increasing evidence is emerging that controlled ovarian hyperstimulation (COH) with exogenous gonadotropins may be detrimental to oogenesis, embryo quality, and endometrial receptivity. This research aimed at assessing the impact of COH on the intrafollicular milieu by comparing follicular fluid (FF) cytokine profiles during stimulated in vitro fertilization (IVF) and modified natural cycle (MNC) IVF. Methods. Ten women undergoing COH IVF and 10 matched women undergoing MNC IVF were recruited for this pilot study. 40 FF cytokine concentrations from individual follicles and plasma were measured by fluid-phase multiplex immunoassay. Demographic/cycle/cytokine data were compared and correlations between cytokines were computed. Results. No significant differences were found between COH and MNC groups for patient and cycle demographics, including outcome. Overall mean FF cytokine levels were higher in the MNC group for 29/40 cytokines, significantly so for leukaemia inhibitory factor and stromal cell-derived factor-1α. Furthermore, FF MNC cytokine correlations were significantly stronger than for COH data. Conclusions. These findings suggest that COH perturbs intrafollicular cytokine networks, in terms of both cytokine levels and their interrelationships. This may impact oocyte maturation/fertilization and embryo developmental competence.

Post-translational dual regulation of cytochrome P450 aromatase at the catalytic and protein levels by phosphorylation/dephosphorylation

The post-translational regulation of aromatase has not been well characterized as compared with transcriptional regulation. Several studies of post-translational regulation have focused on decreases in catalytic activity following phosphorylation. We report here dual post-translational regulation of aromatase, at the catalytic activity and protein levels. Microsomal aromatase prepared from JEG-3 cells was rapidly inactivated and subsequently degraded in the presence of a cytosolic fraction with calcium, magnesium, and ATP. In a reconstituted system consisting of microsomal and cytosolic fractions, aromatase was protected from protein degradation by treatment with alkaline phosphatase, whereas degradation was enhanced by treatment with calcineurin inhibitors (FK506 and cyclosporin A). Furthermore, aromatase was protected from degradation by treatment with kinase inhibitors, especially the calcium/calmodulin kinase inhibitors KN62 and KN93. Similarly to the reconstituted system, aromatase in cultured JEG-3 cells was protected from degradation by KN93, whereas FK503 increased degradation in the presence of cycloheximide, although cellular aromatase mRNA levels were unchanged by these reagents. Knockdown of calcineurin and calcium/calmodulin kinase II (CaMKII) with small interfering RNAs resulted in a dose-dependent increase in aromatase degradation and protection from degradation, respectively. The cytosol fraction-dependent phosphorylation of microsomal aromatase was inhibited by calcineurin, KN62, and KN93, and promoted by CaMKII and FK506. These results indicate that aromatase is regulated acutely at the catalytic activity level and subsequently at the enzyme content level by CaMKII/calcineurin-dependent phosphorylation/dephosphorylation.

C-reactive protein and postmenopausal breast cancer risk: results from the E3N cohort study

BACKGROUND

C-reactive protein (CRP), a marker of low-grade inflammation, has been associated with breast cancer risk, but results are scarce and inconsistent.

METHODS

A case-control study nested within the E3N prospective cohort included 549 postmenopausal breast cancer cases and 1,040 matched controls, all free of breast cancer at baseline. Serum levels of CRP were measured in samples collected between 1995 and 1999. Unconditional logistic regression models were used to evaluate the association between CRP and breast cancer risk, adjusting for matching factors and known breast cancer risk factors.

RESULTS

No association was observed between CRP levels and breast cancer risk overall. However, a significant interaction was observed between CRP levels and body mass index (BMI). A statistically significant increase in breast cancer risk was observed in overweight and obese women (BMI ≥ 25 kg/m(2)) (OR 1.92, 95 % CI 1.20-3.08 for CRP ≥ 2.5 mg/L compared with CRP < 1.5 mg/l, p trend = 0.003, p interaction between CRP and BMI = 0.03). Similar results were observed in women with waist circumference (WC) ≥ 88 cm (p trend = 0.01, p interaction = 0.06) and waist-to-hip ratio (WHR) ≥ 0.80 (p trend = 0.06, p interaction = 0.35). CRP levels were not associated with breast cancer risk in women with normal BMI, WC, or WHR.

CONCLUSIONS

We found a positive association between CRP levels and postmenopausal breast cancer risk restricted to women with excess adiposity. The suggested relationship between low-grade inflammation, abdominal adiposity, and postmenopausal breast cancer risk deserves further investigation.

17β-Estradiol and estradiol fatty acyl esters and estrogen-converting enzyme expression in adipose tissue in obese men and women

CONTEXT

Obesity is associated with increased circulating 17β-estradiol (E₂), but less is known about E₂ concentrations in adipose tissue. In addition to E₂, adipose tissue synthesizes E₂ fatty acyl esters (E₂-FAE).

OBJECTIVE

The aim was to compare estrogen concentrations and expression of estrogen-converting enzymes in adipose tissue between severely obese men and women.

DESIGN AND SETTING

Tissue samples were obtained during elective surgery in University Central Hospital in the years 2008 through 2011.

PATIENTS

We studied 14 men and 22 premenopausal women undergoing bariatric surgery and 10 control women operated for nonmalignant reasons.

INTERVENTIONS

Paired samples were taken from abdominal sc and visceral adipose tissue and serum and analyzed for E₂ and E₂-FAE by fluoroimmunoassay and liquid chromatography-tandem mass spectrometry. mRNA expression of genes was analyzed by quantitative PCR.

RESULTS

Compared with men, E₂ levels in sc adipose tissue in obese women were higher, along with higher relative mRNA expression of steroid sulfatase and 17β-hydroxysteroid dehydrogenases 1, 7, and 12. In men, E₂-FAE concentrations in adipose tissue were similar to E₂ but in women significantly lower compared with E₂. Adipose tissue E₂-FAE and serum E₂-FAE levels correlated positively in obese subjects. Serum E₂ did not significantly correlate with E₂ concentration or mRNA expression of genes in adipose tissue in obese men or women.

CONCLUSIONS

The production of E₂ by the large adipose mass was not reflected by increased circulating E₂ concentrations in severely obese men or women. However, adipose tissue may contribute to concentrations of serum E₂-FAE.

Obesity and breast cancer: role of inflammation and aromatase

Obesity is now recognised to be an inflammatory condition in which dysregulated metabolism plays an integral role. Inflammatory mediators regulate aromatase expression in the human breast as one mechanism whereby they increase the risk of breast cancer, especially in women who are obese.

Aromatase activity induction in human adipose fibroblasts by retinoic acids via retinoic acid receptor α

Estrogen synthesis in adipose tissue is associated with the development of breast cancer. Tumors are preferentially found in breast quadrants with strongest expression of the cytochrome P450 aromatase (encoded by the gene CYP19A1). Several promoters regulated by various hormonal factors drive aromatase expression in human breast adipose fibroblasts (BAFs). As adipose tissue is a major source of retinoids, in this study, we investigated their role in the regulation of aromatase expression. The retinoids all-trans-retinoic acid (at-RA) and 9-cis-RA induce aromatase activity in human BAFs. In BAFs, at-RA induces aromatase gene expression via promoter I.4. In 3T3-L1 cells, both retinoids specifically drive luciferase reporter gene expression under the control of aromatase promoter I.4, whereas other promoters active in human adipose tissue are insensitive. Activation by retinoids depends on a 467 bp fragment (-256/+211) of promoter I.4 containing four putative retinoic acid response elements (RAREs). Site-directed mutagenesis revealed that only RARE2 (+91/+105) mediates the retinoid-dependent induction of reporter gene activity. In 3T3-L1 preadipocytes and human BAFs, RA receptor α (RARα (RARA)) expression is predominant, whereas RARβ (RARB) or RARγ (RARG) expression is low. Electrophoretic mobility shift assays with nuclear extracts obtained from human BAFs and 3T3-L1 cells identified a specific RARE2-binding complex. Retinoids enhanced complex formation, whereas pre-incubation with anti-RARα antibodies prohibited the binding of RARα to RARE2. Chromatin immunoprecipitation showed RA-dependent binding of RARα to the RARE2-containing promoter region in vivo. Furthermore, we provide evidence that RARE2 is also necessary for the basal activation of promoter I.4 in these cells. Taken together, these findings indicate a novel retinoid-dependent mechanism of aromatase activity induction in adipose tissue.

Intracrine oestrogen production and action in breast cancer: an epigenetic focus

Epigenome changes have been widely demonstrated to contribute to the initiation and progression of a vast array of cancers including breast cancer. The reversible process of many epigenetic modifications is thus an attractive feature for the development of novel therapeutic measures. In oestrogen receptor α (hereinafter referred to as ER) positive tumours, endocrine therapies have proven beneficial in patient care, particularly in postmenopausal women where two-thirds of tumours are oestrogen dependent. However, resistance to such therapies is a common feature amongst individuals. In the current review, we discuss the influence that epigenetics has on oestrogen dependent breast cancers, in particular (i) the production of intracrine oestrogen in postmenopausal women, (ii) the action of oestrogen on epigenetic processes, and (iii) the links between epigenetics and endocrine resistance and the current advancements in epigenetic therapy that target this process. This article is part of a Special Issue entitled 'CSR 2013'.

Interaction of JAK with steroid receptor function

The function of steroid receptors is not only regulated by steroid hormones, but also by multiple cellular signaling cascades activated by membrane-bound receptors which are stimulated by growth factors or cytokines. Cross-talk between JAK and steroid receptors plays a central role in the regulation of a multitude of physiological processes and aberrant signaling is involved in the development of numerous diseases including cancer. In this review we provide a brief summary of the knowledge of interactions between JAK and the function of steroid receptors in normal cells and tissues and in diseases.

Hormonal, metabolic, and inflammatory profiles and endometrial cancer risk within the EPIC cohort--a factor analysis

A "Western" lifestyle characterized by physical inactivity and excess weight is associated with a number of metabolic and hormonal dysregulations, including increased circulating estrogen levels, hyperinsulinemia, hyperglycemia, and chronic inflammation. The same hormonal and metabolic axes might mediate the association between this lifestyle and the development of endometrial cancer. Using data collected within the European Prospective Investigation into Cancer and Nutrition (EPIC), a prospective cohort study carried out in 10 European countries during 1992-2000, we conducted a factor analysis to delineate important components that summarize the variation explained by a set of biomarkers and to examine their association with endometrial cancer risk. Prediagnostic levels of testosterone, androstenedione, dehydroepiandrosterone sulfate, sex hormone-binding globulin, estrone, estradiol, C-peptide, insulin-like growth factor-binding proteins 1 and 2, adiponectin, high- and low-density lipoprotein cholesterol, glucose, triglycerides, tumor necrosis factor (TNF) α, soluble TNF receptors 1 and 2, C-reactive protein, interleukin-6, and interleukin-1 receptor antagonist were measured in 233 incident endometrial cancer cases and 446 matched controls. Factor analysis identified 3 components associated with postmenopausal endometrial cancer risk that could be labeled "insulin resistance/metabolic syndrome," "steroids," and "inflammation" factors. A fourth component, "lipids," was not significantly associated with endometrial cancer. In conclusion, besides the well-known associations of risk with sex hormones and insulin-regulated physiological axes, our data further support the hypothesis that inflammation factors play a role in endometrial carcinogenesis.

Origins and actions of tumor necrosis factor α in postmenopausal breast cancer

Tumor necrosis factor α (TNFα) has many roles in both physiological and pathological states. Initially thought to cause necrosis of tumors, research has shown that in many tumor types, including breast cancer, TNFα contributes to growth and proliferation. The presence of TNFα-derived from the tumor and infiltrating immune cells-within a breast tumor microenvironment has been correlated with a more aggressive phenotype, and the postmenopausal ER+ subtype of breast cancers appears to strongly respond to its many pro-growth signaling functions. We discuss how TNFα regulates estrogen biosynthesis within the breast, affecting the activity of the key estrogen-synthesizing enzymes aromatase, estrone sulfatase, and 17β-HSD type 1. Additionally, we describe the anti-adipogenic actions of TNFα that are critical in preventing adjacent estrogen-producing adipose fibroblasts from differentiating, ensuring that the tumor maintains a constant source of estrogen-producing cells. We examine how the increased risk of developing breast cancer in older and obese individuals may be linked to the levels of TNFα in the body. Finally, we evaluate the feasibility of targeting TNFα and its associated pathways as a novel approach to breast cancer therapeutics.

Involvement of early growth response factors in TNFα-induced aromatase expression in breast adipose

Expression of the oestrogen producing enzyme, aromatase, is regulated in a tissue-specific manner by its encoding gene CYP19A1. In post-menopausal women, the major site for oestrogen production in the breast is the adipose, where CYP19A1 transcription is driven by the distal promoter I.4 (PI.4). Transcripts via this promoter are also elevated in breast adipose fibroblasts (BAFs) adjacent to a tumour. PI.4 expression is stimulated by a number of cytokines, and TNFα is one such factor. The transcriptional mechanisms induced by TNFα to stimulate PI.4 are poorly characterised. We show that the early growth response (Egr) transcription factors play an important role in the TNFα-induced signalling pathway resulting in elevated PI.4 transcription. TNFα treatment of BAFs increases mRNA levels of all four Egr family members, with EGR2 being the most highly expressed. Overexpression of EGR2 causes an increase in endogenous CYP19A1 expression in preadipocyte Simpson-Golabi-Behmel syndrome cells, driven by increases in PI.4-specific transcripts. PI.4 luciferase reporter activity is increased in a dose-dependent manner by EGR2, EGR3 and EGR4, with EGR2 showing the most potent activation of promoter activity. Deletion analysis indicates that this promoter activity is being indirectly mediated by a short region of the promoter not containing any previously characterised binding sites, and we further show that EGR2 does not bind directly or indirectly to this promoter region. However, siRNA knockdown of the Egrs reduces the total and PI.4-derived CYP19A1 transcription in BAFs. These studies unveil a novel component of the aromatase gene regulatory network and further enhance the complexity of oestrogen production in the breast.

Epigenetic mechanisms regulate the prostaglandin E receptor 2 in breast cancer

The increase in local oestrogen production seen in oestrogen receptor positive (ER+) breast cancers is driven by increased activity of the aromatase enzyme. CYP19A1, the encoding gene for aromatase, is often overexpressed in the oestrogen-producing cells of the breast adipose fibroblasts (BAFs) surrounding an ER+ tumour, and the molecular processes underlying this upregulation is important in the development of breast-specific aromatase inhibitors for breast cancer therapy. Prostaglandin E2 (PGE2), a factor secreted by tumours, is known to stimulate CYP19A1 expression in human BAFs. The hormonal regulation of this process has been examined; however, what is less well understood is the emerging role of epigenetic mechanisms and how they modulate PGE2 signalling. This present study characterises the epigenetic processes underlying expression of the prostanoid receptor EP2 in the context of ER+ breast cancer. Sodium bisulphite sequencing of CpG methylation within the promoter region of EP2 revealed that an inverse correlation existed between methylation levels and relative EP2 expression in breast cancer cell lines MDA-MB-231, MCF7 and MCF10A but not in HS578t and T47D. Inhibition of DNA methylation with 5-aza-2'-deoxycytidine (5aza) and histone deacetylation with Trichostatin A (TSA) resulted in upregulation of EP2 mRNA in all cell lines with varying influences of each epigenetic process observed. Expression of EP2 was detected in human BAFs despite a natively methylated promoter, and this expression was further increased upon 5aza treatment. An examination of 3 triple negative, 3 ductal carcinoma in situ and 3 invasive ductal carcinoma samples revealed that there was no change in EP2 promoter methylation status between normal and cancer associated stroma, despite observed differences in relative mRNA levels. Although EP2 methylation status is inversely correlated to expression levels in established breast cancer cell lines, we could not identify that such a correlation existed in tumour-associated stroma cells.

Glucocorticoid-induction of hypothalamic aromatase via its brain-specific promoter

In the brain, a 36-kb distal promoter (I.f) regulates the Cyp19a1 gene that encodes aromatase, the key enzyme for estrogen biosynthesis. Local estrogen production in the brain regulates critical functions such as gonadotropin secretion and sexual behavior. The mechanisms that control brain aromatase production are not well understood. Here we show that the glucocorticoid dexamethasone robustly increases aromatase mRNA and protein by up to 98-fold in mouse hypothalamic cell lines in a dose- and time-dependent fashion. Using deletion mutants of the brain-specific promoter I.f and chromatin immunoprecipitation-PCR, we isolated a distinct region (-500/-200 bp) which becomes enriched in bound glucocorticoid receptor upon dexamethasone stimulation. A glucocorticoid antagonist or siRNA based knockdown of glucocorticoid receptor ablated dexamethasone stimulation of aromatase expression. Our findings demonstrate how glucocorticoids alter aromatase expression in the hypothalamus and might indicate a mechanism whereby glucocorticoid action modifies gonadotropin pulses and the menstrual cycle.

The role of cytokines in cardiovascular disease in menopause

Various studies suggest that increased levels of pro-inflammatory cytokines play a key role in the declining ovarian function and the resulting complications associated with menopause. In this review article, the authors outline the role of pro- and anti-inflammatory cytokines in cardiovascular disease during menopause.