Brca1 Mutations Enhance Mouse Reproductive Functions by Increasing Responsiveness to Male-Derived Scent

We compared the gene expression profiles of ovarian granulosa cells harboring either mutant or wild type Brca1 to follow up on our earlier observation that absence of a functional Brca1 in these important regulators of menstrual/estrous cycle progression leads to prolongation of the pre-ovulatory phase of the estrous cycle and to increased basal levels of circulating estradiol. Here we show that ovarian granulosa cells from mice carrying a conditional Brca1 gene knockout express substantially higher levels of olfactory receptor mRNA than granulosa cells from wild type littermates. This led us to hypothesize that reproductive functions in mutant female mice might be more sensitive to male-derived scent than in wild type female mice. Indeed, it is well established that isolation from males leads to complete cessation of mouse estrous cycle activity while exposure to olfactory receptor ligands present in male urine leads to resumption of such activity. We found that Brca1-/- female mice rendered anovulatory by unisexual isolation resumed ovulatory activity more rapidly than their wild type littermates when exposed to bedding from cages where males had been housed. The prime mediator of this increased responsiveness appears to be the ovary and not olfactory neurons. This conclusion is supported by the fact that wild type mice in which endogenous ovaries had been replaced by Brca1-deficient ovarian transplants responded to male-derived scent more robustly than mutant mice in which ovaries had been replaced by wild type ovarian transplants. Our findings not only have important implications for our understanding of the influence of olfactory signals on reproductive functions, but also provide insights into mechanisms whereby genetic risk factors for breast and extra uterine Müllerian carcinomas may influence menstrual activity in human, which is itself an independent risk factor for these cancers.

Endogenous Sex Steroid Hormones, Lipid Subfractions, and Ectopic Adiposity in Asian Indians

BACKGROUND

Estradiol, testosterone (T), and sex hormone binding globulin (SHBG) levels are associated with lipid subfractions in men and women. Our objective was to determine if associations are independent from adipose tissue area among Asian Indians.

METHODS

We used data from 42 women and 57 Asian Indian men who did not use exogenous steroids or lipid-lowering medications. Lipoprotein subfractions including low-density lipoprotein cholesterol (LDL), very low-density lipoprotein cholesterol (VLDL), and intermediate density lipoprotein (IDL) were assessed by ion mobility spectrometry. Intra-abdominal adiposity was assessed by computed tomography. Multivariable regression models estimated the association between sex hormones with lipoprotein subfractions before and after adjustment for adiposity.

RESULTS

Among women, lower logSHBG levels were associated with smaller logLDL particle size and higher logtriglycerides, logVLDL, and logIDL, although these associations were attenuated with adjustment for visceral adiposity in particular. Among women, lower logSHBG levels was significantly associated with lower logmedium LDL and logsmall LDL concentrations even after consideration of visceral and hepatic adiposity and insulin resistance as represented by the homeostasis model assessment of insulin resistance (HOMA-IR). Among men, lower logSHBG was also associated with smaller logLDL peak diameter size and higher logtriglycerides and logVLDL, even after adjustment for HOMA-IR and adiposity. Relationships between sex steroids and lipid subfractions were not significant among women. Among men, higher total testosterone was associated with higher logHDL and logLDL particle size, and lower logtriglycerides and logVLDL, but these associations were partially attenuated with adjustment for adiposity and HOMA-IR.

CONCLUSIONS

Among Asian Indians, SHBG is associated with more favorable lipid subfraction concentrations, independent of hepatic and visceral fat.

Effects of exercise dose on endogenous estrogens in postmenopausal women: a randomized trial

Exercise dose comparison trials with biomarker outcomes can identify the amount of exercise required to reduce breast cancer risk and also strengthen the causal inference between physical activity and breast cancer. The Breast Cancer and Exercise Trial in Alberta (BETA) tested whether or not greater changes in estradiol (E2), estrone, and sex hormone-binding globulin (SHBG) concentrations can be achieved in postmenopausal women randomized to 12 months of HIGH (300 min/week) vs MODERATE (150 min/week) volumes of aerobic exercise. BETA included 400 inactive postmenopausal women aged 50-74 years with BMI of 22-40 kg/m(2). Blood was drawn at baseline and 6 and 12 months. Adiposity, physical fitness, diet, and total physical activity were assessed at baseline and 12 months. Intention-to-treat analyses were performed using linear mixed models. At full prescription, women exercised more in the HIGH vs MODERATE group (median min/week (quartiles 1,3): 253 (157 289) vs 137 (111 150); P<0.0001). Twelve-month changes in estrogens and SHBG were <10% on average for both groups. No group differences were found for E2, estrone, SHBG or free E2 changes (treatment effect ratios (95% CI) from linear mixed models: 1.00 (0.96-1.06), 1.02 (0.98-1.05), 0.99 (0.96-1.02), 1.01 (0.95, 1.06), respectively, representing the HIGH:MODERATE ratio of geometric mean biomarker levels over 12 months; n=382). In per-protocol analyses, borderline significantly greater decreases in total and free E2 occurred in the HIGH group. Overall, no dose effect was observed for women randomized to 300 vs 150 min/week of moderate to vigorous intensity exercise who actually performed a median of 253 vs 137 min/week. For total and free E2, the lack of differential effect may be due to modest adherence in the higher dose group.

Reprint of "Use of medroxyprogesterone acetate for hormone therapy in postmenopausal women: Is it safe?"

Medroxyprogesterone acetate (MPA) has been in clinical use for over 30 years, and was generally considered to be safe until the results of long-term studies of postmenopausal hormone therapy (HT) using treatment with conjugated equine estrogens (CEE) combined with MPA and CEE alone suggested that MPA, and perhaps other progestogens, may play a role in the increased risk of breast cancer and cardiovascular diseases. This review examines critically the safety of MPA in terms of breast cancer and cardiovascular disease risk, and its effects on brain function. Research into mechanisms by which MPA might cause adverse effects in these areas, combined with the available clinical evidence, suggests a small increase in relative risk for breast cancer and stroke, and a decline in cognitive function, in older women using MPA with an estrogen for postmenopausal HT. However, short-term (less than 5 years) use of MPA with an estrogen in the years immediately after the onset of menopause for the management of vasomotor symptoms does not appear to be associated with any increased risk of these disorders.

Endogenous sex steroid hormones and glucose in a South-Asian population without diabetes: the Metabolic Syndrome and Atherosclerosis in South-Asians Living in America pilot study

AIMS

To examine the associations between endogenous sex steroid hormones (oestradiol, testosterone and sex hormone-binding globulin) with diabetes risk in a South-Asian population living in the USA.

METHODS

We used data from the Metabolic Syndrome and Atherosclerosis in South-Asians Living in America pilot study. The analytical sample included 60 women and 45 men of Asian Indian origin living in the San Francisco Bay Area, who were free from diabetes and cardiovascular disease and did not use exogenous sex steroids. Sex steroid hormone levels were assessed by validated conventional radioimmunoassays, and visceral and hepatic adiposity were assessed by computed tomography. We used multivariable regression to examine the association between endogenous sex steroid hormone levels (log-transformed) and fasting glucose and 2-h glucose levels in a series of sex-stratified models adjusted for age, waist circumference, visceral and hepatic adiposity, and insulin resistance.

RESULTS

In age-adjusted models, lower levels of sex hormone-binding globulin (β = -0.18, 95% CI -0.30, -0.06) and higher levels of free testosterone (β = 0.14, 95% CI 0.02, 0.26) were associated with elevated fasting glucose levels in South-Asian women, whereas lower levels of sex hormone-binding globulin (β = -0.14, 95% CI -0.26, -0.02) and lower levels of total testosterone (β = -0.12, 95% CI -0.24, 0.00) were associated with elevated fasting glucose levels in South-Asian men. Adjustment for waist circumference, visceral adiposity and insulin resistance attenuated most of these associations, while adjustment for hepatic adiposity strengthened some of the observed associations. Similar results were found for 2-h glucose levels.

CONCLUSIONS

Results were consistent with previous research, which suggests that endogenous sex steroid hormones are a risk factor for diabetes across multiple race/ethnic groups. Additional studies are needed to determine whether visceral fat is a mediator or confounder of associations between sex steroid hormone and glucose levels.

A Prospective Evaluation of Endogenous Sex Hormone Levels and Colorectal Cancer Risk in Postmenopausal Women

BACKGROUND

Postmenopausal hormone therapy use has been associated with lower colorectal cancer risk in observational studies. However, the role of endogenous sex hormones in colorectal cancer development in postmenopausal women is uncertain.

METHODS

The relation of colorectal cancer risk with circulating levels of estradiol, estrone, free (bioactive) estradiol, progesterone and sex hormone-binding globulin (SHBG) was determined in a nested case-control study of 1203 postmenopausal women (401 case patients and 802 age and race/ethnicity-matched control patients) enrolled in the Women's Health Initiative Clinical Trial (WHI-CT) who were not assigned to the estrogen-alone or combined estrogen plus progestin intervention groups. We used multivariable-adjusted conditional logistic regression models that included established colorectal cancer risk factors. All statistical tests were two-sided.

RESULTS

Comparing extreme quartiles, estrone (odds ratio [OR]q4-q1 = 0.44, 95% confidence interval [CI] = 0.28 to 0.68, P trend = .001), free estradiol (ORq4-q1 = 0.43, 95% CI = 0.27 to 0.69, P trend ≤ .0001), and total estradiol (ORq4-q1 = 0.58, 95% CI = 0.38 to 0.90, P trend = .08) were inversely associated with colorectal cancer risk. SHBG levels were positively associated with colorectal cancer development (OR[q4-q1] = 2.30, 95% CI = 1.51 to 3.51, P trend ≤ .0001); this association strengthened after further adjustment for estradiol and estrone (ORq4-q1 = 2.50, 95% CI = 1.59 to 3.92, P trend < .0001). Progesterone was not associated with colorectal cancer risk.

CONCLUSION

Endogenous estrogen levels were inversely, and SHBG levels positively, associated with colorectal cancer risk, even after control for several colorectal cancer risk factors. These results suggest that endogenous estrogens may confer protection against colorectal tumorigenesis among postmenopausal women.

Abstract 2767: Investigation of the relationship between crown-like structures and adipose tissue hormone levels among postmenopausal women with breast cancer

Introduction: Increased levels of circulating estrogens are associated with elevated risks of postmenopausal breast cancer. Previously, we showed that levels of sex steroid hormones in breast adipose tissue are positively correlated with circulating hormones. Further evaluation of hormone levels in breast tissues may help to explain the relationship between estrogens and breast cancer risk. Specifically, data suggest that focal breast lesions consisting of macrophages encircling dying adipocytes, referred to as “crown-like structures (CLS)”, are associated with increased aromatase activity, which could increase conversion of androgens to estrogens locally in the breast. Therefore, we assessed whether the presence of CLS affects the correlations between blood and breast adipose tissue hormone levels. Methods: Participants included 84 postmenopausal women with invasive breast cancer in the Polish Breast Cancer Study, a population based case-control study conducted from 2000 to 2003. We previously reported sex steroid hormone levels in cancer-free breast adipose tissue removed as part of breast excisions performed for cancer. Here, using immunohistochemical stains, we evaluated the number of CD68 positive macrophages and the presence of full CLS (i.e., complete adipocyte encirclement) in benign breast tissue sections prepared from surgical pathology specimens containing breast cancer. The relationship between the number of CD68 positive macrophages per unit area of fat and hormone levels was examined using Spearman rank correlations (rs). We assessed potential effect modification of the association between blood and tissue hormone levels by presence or absence of CLS by including an interaction term in linear regression models. Results: The number of CD68 positive macrophages per unit area of fat was not significantly correlated with levels of estrone, estradiol, androstenedione or testosterone measured in blood (rs = 0.001, -0.04, -0.07, and -0.09, respectively; p&gt;0.05) or breast adipose tissue (rs = -0.15, 0.06, -0.06, and -0.08, respectively; p&gt;0.05). Correlations between serum and adipose tissue hormones did not statistically significantly differ between women with CLS (n = 30) compared to those without CLS (n = 54). CLS were found more frequently in breast adipose tissue from overweight (i.e., women with a body mass index (BMI) between 25 and 29.9) (43%) and obese women (BMI &gt;30) (30%) versus normal weight women, with (BMI between 18.5 and 24.9), (27%); (p = 0.04, χ2 test). The number of CD68 positive macrophages per unit area of fat was not significantly related to BMI (p = 0.31). Conclusion: Among postmenopausal women with invasive breast cancer, the presence of CLS was more common among overweight and obese women, but CLS did not influence the correlation between circulating and breast adipose tissue sex steroid hormone levels.

Citation Format: Maeve Mullooly, Hannah P. Yang, Roni T. Falk, Sarah Nyante, Renata Cora, Ruth M. Pfeiffer, Derek C. Radisky, Daniel W. Visscher, Lynn C. Hartmann, Amy C. Degnim, Frank Z. Stanczyk, Jonine F. Figueroa, Montserrat Garcia-Closas, Jolanta Lissowska, Melissa T. Troester, Louise A. Brinton, Mark E. Sherman, Gretchen L. Gierach. Investigation of the relationship between crown-like structures and adipose tissue hormone levels among postmenopausal women with breast cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2767. doi:10.1158/1538-7445.AM2015-2767

Relationships of sex steroid hormone levels in benign and cancerous breast tissue and blood: A critical appraisal of current science

A systematic review of the literature on sex steroid measurement in breast tissue identified only 19 articles meeting the following criteria: menopausal status given; steroids measured in tissue homogenates by conventional RIA with a purification step or by mass spectrometry; and values reported per g tissue or per g protein. Twelve articles were analyzed in detail for: ratios of sex steroid hormone levels in cancerous or benign tissues to blood levels, stratified by menopausal status; ratios between the different hormone levels within tissues or within blood; and difference in these ratios between tissue and blood compartments. Estrogen and androgen concentrations varied greatly in benign and cancerous tissues and in blood between individuals. Postmenopausal, but not premenopausal, estradiol concentrations were significantly higher in cancerous compared to benign breast tissue. The estradiol/estrone ratio was lowest in premenopausal benign tissue, and substantially higher in premenopausal cancerous tissue and postmenopausal benign and cancerous tissues. Estradiol and estrone levels were considerably higher in tissue than in plasma in both premenopausal and postmenopausal women. Androgen levels were generally higher in the benign than the cancerous tissue, and tissue androgen levels were higher than in plasma, suggesting in situ aromatization of androgens to estrogens in breast cancer tissue. Limited available data on levels of hydroxylated estrogens in breast tissue compared to corresponding levels in plasma or urine were reviewed, but due to the paucity of studies no conclusions can presently be drawn regarding the relationship of the 2-hydroxyestrone:16α-hydroxyestrone ratio to breast cancer risk and genotoxic effects of 4-hydroxylated estrogens. Finally, data on hormone levels in breast adipose tissue were analyzed; high levels of androstenedione and testosterone and significant estrone and estradiol levels in breast adipocytes from postmenopausal breast cancer patients are consistent with an obesity-inflammation-aromatase axis occurring locally in breast tissue. The controversies regarding the source of intratumoral estrogens in the breast are summarized.

Adolescent endogenous sex hormones and breast density in early adulthood

INTRODUCTION

During adolescence the breasts undergo rapid growth and development under the influence of sex hormones. Although the hormonal etiology of breast cancer is hypothesized, it remains unknown whether adolescent sex hormones are associated with adult breast density, which is a strong risk factor for breast cancer.

METHODS

Percentage of dense breast volume (%DBV) was measured in 2006 by magnetic resonance imaging in 177 women aged 25-29 years who had participated in the Dietary Intervention Study in Children from 1988 to 1997. They had sex hormones and sex hormone-binding globulin (SHBG) measured in serum collected on one to five occasions between 8 and 17 years of age. Multivariable linear mixed-effect regression models were used to evaluate the associations of adolescent sex hormones and SHBG with %DBV.

RESULTS

Dehydroepiandrosterone sulfate (DHEAS) and SHBG measured in premenarche serum samples were significantly positively associated with %DBV (all P trend ≤0.03) but not when measured in postmenarche samples (all P trend ≥0.42). The multivariable geometric mean of %DBV across quartiles of premenarcheal DHEAS and SHBG increased from 16.7 to 22.1 % and from 14.1 to 24.3 %, respectively. Estrogens, progesterone, androstenedione, and testosterone in pre- or postmenarche serum samples were not associated with %DBV (all P trend ≥0.16).

CONCLUSIONS

Our results suggest that higher premenarcheal DHEAS and SHBG levels are associated with higher %DBV in young women. Whether this association translates into an increased risk of breast cancer later in life is currently unknown.

CLINICAL TRIALS REGISTRATION

ClinicalTrials.gov Identifier, NCT00458588 April 9, 2007; NCT00000459 October 27, 1999.

Effect of finasteride on serum androstenedione and risk of prostate cancer within the prostate cancer prevention trial: differential effect on high- and low-grade disease

OBJECTIVE

To evaluate the effect of finasteride on serum androst-4-ene-3,17-dione (androstenedione) and its association with prostate cancer risk among subjects who participated in the Prostate Cancer Prevention Trial.

METHODS

We analyzed serum androstenedione levels in 317 prostate cancer cases and 353 controls, nested in the Prostate Cancer Prevention Trial, a randomized placebo-controlled trial that found finasteride decreased prostate cancer risk. Androstenedione is the second most important circulating androgen in men besides testosterone and also a substrate for 5α-reductase enzyme.

RESULTS

We observed a 22% increase in androstenedione levels compared with the baseline values in subjects who were treated with finasteride for 3 years. This significant increase did not vary by case-control status. Adjusted odds ratio and 95% confidence interval for the third tertile of absolute change in androstenedione levels compared with the first tertile were 0.42 (95% confidence interval, 0.19-0.94) for low-grade (Gleason score <7) cases. Similar results were observed when analyzed using percent change. There were no significant associations between serum androstenedione levels and the risk of high-grade disease.

CONCLUSION

The results of this nested case-control study confirm that finasteride blocks the conversion of testosterone to dihydrotestosterone (DHT) and of androstenedione to 5α-androstanedione-3,17-dione, which also leads to the reduction of DHT formation. This decrease in DHT may help reduce the risk of low-grade prostate cancer in men. Our data on a differential effect of androstenedione also suggest that some high-grade prostate cancers may not require androgen for progression.

CCR5 Expression Levels in HIV-Uninfected Women Receiving Hormonal Contraception

Human immunodeficiency virus (HIV) infectivity increases as receptor/coreceptor expression levels increase. We determined peripheral CD4, CCR5, and CXCR4 expression levels in HIV-uninfected women who used depot medroxyprogesterone acetate (DMPA; n = 32), the levonorgestrel-releasing intrauterine device (LNG-IUD; n = 27), oral contraceptive pills (n = 32), or no hormonal contraception (n = 33). The use of LNG-IUD increased the proportion of CD4(+) and CD8(+) T cells that expressed CCR5; increases in the magnitude of T-cell subset CCR5 expression were observed with DMPA and LNG-IUD use (P < .01 for all comparisons). LNG-IUD and, to a lesser extent, DMPA use were associated with increased peripheral T-cell CCR5 expression.

Anti-Müllerian hormone concentrations in premenopausal women and breast cancer risk

Laboratory models support an inverse association between anti-Müllerian hormone (AMH) and breast tumor development. Human studies are lacking; one study (N = 105 cases, 204 controls) with prospectively collected serum reported the opposite-an approximate 10-fold increase in breast cancer risk comparing fourth with first quartile AMH levels. We investigated the relation between serum AMH levels and breast cancer risk in a case-control (N = 452 cases, 902 controls) study nested within the prospective Sister Study cohort of 50,884 women. At enrollment, participants were ages 35 to 54, premenopausal, and completed questionnaires on medical and family history, lifestyle factors, and demographics. AMH (ng/mL) was measured by ultrasensitive ELISA in serum collected at enrollment and log-transformed for analysis. Multivariate conditional logistic regression was used to calculate ORs and 95% confidence intervals (CI) to account for matching on age and enrollment year. Mean age at enrollment was 46.8 years with an average 2.9 years from blood draw to breast cancer diagnosis (SD = 1.9). AMH concentrations were below the limit of detection (0.003 ng/mL) for approximately 25% of samples. Compared with samples below the LOD, women with AMH >2.84 ng/mL (90th percentile among controls) had a 2-fold increase in breast cancer odds (OR, 2.25; 95% CI, 1.26-4.02). For each 1-unit increase in lnAMH, overall breast cancer odds increased by 8% (OR, 1.08; 95% CI, 1.02-1.15) and odds of estrogen receptor-positive, invasive disease increased by 15% (OR, 1.15; 95% CI, 1.05-1.25). Our findings demonstrate an overall positive relation between AMH and breast cancer.

Adolescent Endogenous Sex Hormones and Breast Density in Early Adulthood

During adolescence the breasts undergo rapid growth and development under the influence of sex hormones. Although the hormonal etiology of breast cancer is hypothesized, it remains unknown whether adolescent sex hormones are associated with adult breast density, which is a strong risk factor for breast cancer. METHODS: Percentage of dense breast volume (%DBV) was measured in 2006 by magnetic resonance imaging in 177 women aged 25–29 years who participated in the Dietary Intervention Study in Children from 1988–1997 and had sex hormones and sex hormone binding globulin (SHBG) measured in serum collected on 1–4 occasions between 8 and 17 years of age. Multivariable linear mixed-effect regression models were used to evaluate the associations of adolescent sex hormones and SHBG with %DBV. RESULTS: Dehydroepiandrosterone sulfate (DHEAS) and SHBG measured in premenarche serum samples were significantly positively associated with %DBV (all Ptrend ≤ 0.03) but not when measured in postmenarche samples (all Ptrend ≥ 0.42). The multivariable geometric mean of %DBV across quartiles of premenarcheal DHEAS and SHBG increased from 16.7% to 22.1% and from 14.1% to 24.3%, respectively. Estrogens, progesterone, androstenedione, and testosterone were not associated with %DBV pre- or post-menarche (all Ptrend ≥ 0.16). CONCLUSIONS: Our results suggest that higher DHEAS and SHBG levels during adolescence, particularly before the onset of menarche, are associated with higher%DBV in young women. Whether this association translates into an increased risk of breast cancer later in life is currently unknown.

Association of endogenous sex hormones with adipokines and ghrelin in postmenopausal women

CONTEXT

Sex hormones, adipokines, and ghrelin have been implicated in central control of appetite, energy homeostasis, maintenance of fat mass, and inflammation. Women tend to gain weight after menopause and adipose tissue is a major source of sex steroid postmenopause. Understanding the dynamics of these analytes are of particular importance in postmenopausal women, who are at greater risk for cardiometabolic diseases.

OBJECTIVES

This study sought to evaluate the associations of adipokines and ghrelin with sex hormone concentrations in postmenopausal women.

DESIGN

We conducted a cross-sectional analysis of baseline clinical trial data.

SETTING

The parent trial was conducted at a university clinical research facility.

PARTICIPANTS

Baseline data from 634 postmenopausal women participating in the Early vs Late Intervention Trial with Estradiol (ELITE). PARTICIPANTS had no history of chronic illness in the past 5 years and were not taking exogenous hormone therapy.

MAIN OUTCOME MEASURES

Serum levels of estrone (E1), total estradiol (E2), free estradiol (FE2), free testosterone (FT), total testosterone (T), and sex hormone-binding globulin (SHBG).

RESULTS

Adjusted for age, race, time since menopause, and body mass index (BMI), leptin concentrations were significantly positively associated with E1, E2, FE2, and FT and inversely associated with SHBG levels. Only the associations of adiponectin with FE2 (inverse) and SHBG (positive) remained significant after controlling for BMI. The inverse associations of adiponectin with E1, E2, and FT were substantially mediated by BMI. Associations of ghrelin with E1, E2, FE2, and SHBG were not independent of BMI. Waist-to-hip circumference ratio was not a mediator in any of the associations.

CONCLUSIONS

In postmenopausal women, leptin and adiponectin concentrations are substantially correlated with sex hormone and SHBG concentrations regardless of obesity status.

Effects of luteinizing hormone receptor signaling in prostate cancer cells

BACKGROUND

The importance of androgen signaling in prostate cancer (PC) is well described and prostate cancer cells retain the ability to directly synthesize androgens. Luteinizing hormone (LH) can induce expression of steroidogenic enzymes and trigger androgen production, but the regulation of this process is not well-described. Here, we explored the impact of silencing LH receptor (LHR) silencing on androgen synthesis and on several relevant signaling pathways in PC.

METHODS

LHR mRNA and protein expression was evaluated in LNCaP PC cells treated with LHR-siRNA. MTS assay was used to measure the effect of LHR-siRNA on proliferation in LNCaP and 22RV1 PC cells. Treated LNCaP and LAPC-3 cells were also assayed for differences in androgen synthesis and expression of steroidogenic enzymes, PSA, AR, and critical signaling molecules including PKA, ERK1/2, PI3K, AKT2, and HER2.

RESULTS

We confirmed that functional LHR is expressed in both androgen-sensitive and castrate-resistant PC specimens. Treatment with LHR-siRNA effectively silenced LHR gene and protein expression and prevented LH-mediated proliferation and androgen synthesis in prostate cancer cells. LHR silencing also downregulated expression of AR, PSA, PKA, ERK1/2, PI3K, AKT2, and HER2.

CONCLUSION

Collectively, these data demonstrate that silencing LHR expression suppresses androgen synthesis and signaling and the LH-LHR pathway may represent a viable therapeutic strategy in PC.

Study design and methods for the Breast Cancer and Exercise Trial in Alberta (BETA)

Background

Exercise has favorable effects on biomarkers associated with a lower risk of breast cancer, however it is unclear if higher doses of exercise provide additional effects. No clinical trial has systematically examined how different exercise volumes influence the mechanisms underlying breast cancer etiology. The Breast Cancer and Exercise Trial in Alberta (BETA) - a follow-up study to the Alberta Physical Activity and Breast Cancer Prevention (ALPHA) Trial - is examining how a one-year, high versus moderate volume aerobic exercise intervention influences several biomechanisms hypothesized to influence breast cancer risk in a group of postmenopausal women. Secondary aims are to compare intervention effects on psychosocial and quality of life outcomes as well as understand exercise adherence at 12 and 24 months, and maintenance of all study outcomes at 24 months.

Methods/Design

The BETA Trial is a two-center, two-armed randomized controlled exercise intervention trial conducted in 400 previously inactive, postmenopausal women aged 50–74 years, in Alberta, Canada. Participants were randomly assigned to a one-year aerobic exercise intervention of either high volume (300 minutes/week) or moderate volume (150 minutes/week). Blood draws and accelerometry were performed at baseline, six and 12 months. Baseline and 12-month measurements were taken of adiposity (including dual energy X-ray absorptiometry and computed tomography scans), physical fitness, dietary intake, self-reported physical activity and sedentary behavior, quality of life, perceived stress, happiness, sleep, and determinants of exercise adherence. Exercise maintenance was assessed and all study measurements were repeated at 24 months. Blood will be analyzed for endogenous estrogens, insulin resistance indicators, and inflammatory markers.

Discussion

The BETA Trial will compare the impact of a high versus moderate volume of aerobic exercise on a variety of biological, physiological, and psychological outcomes of relevance to postmenopausal women. A tightly controlled exercise intervention and objective outcome measurements are methodological strengths. The BETA Trial will inform future prevention initiatives by assessing adherence to a high volume of exercise over 12 months by postmenopausal women, and the ability of these women to maintain activity over the longer-term. The ultimate objective is to inform public health guidelines for reducing breast cancer risk through physical activity.

Trial registration

Clinical Trials Registration Number: NCT01435005

Association of endogenous sex hormones with adipokines and ghrelin in postmenopausal women

CONTEXT

Sex hormones, adipokines, and ghrelin have been implicated in central control of appetite, energy homeostasis, maintenance of fat mass, and inflammation. Women tend to gain weight after menopause and adipose tissue is a major source of sex steroid postmenopause. Understanding the dynamics of these analytes are of particular importance in postmenopausal women, who are at greater risk for cardiometabolic diseases.

OBJECTIVES

This study sought to evaluate the associations of adipokines and ghrelin with sex hormone concentrations in postmenopausal women.

DESIGN

We conducted a cross-sectional analysis of baseline clinical trial data.

SETTING

The parent trial was conducted at a university clinical research facility.

PARTICIPANTS

Baseline data from 634 postmenopausal women participating in the Early vs Late Intervention Trial with Estradiol (ELITE). PARTICIPANTS had no history of chronic illness in the past 5 years and were not taking exogenous hormone therapy.

MAIN OUTCOME MEASURES

Serum levels of estrone (E1), total estradiol (E2), free estradiol (FE2), free testosterone (FT), total testosterone (T), and sex hormone-binding globulin (SHBG).

RESULTS

Adjusted for age, race, time since menopause, and body mass index (BMI), leptin concentrations were significantly positively associated with E1, E2, FE2, and FT and inversely associated with SHBG levels. Only the associations of adiponectin with FE2 (inverse) and SHBG (positive) remained significant after controlling for BMI. The inverse associations of adiponectin with E1, E2, and FT were substantially mediated by BMI. Associations of ghrelin with E1, E2, FE2, and SHBG were not independent of BMI. Waist-to-hip circumference ratio was not a mediator in any of the associations.

CONCLUSIONS

In postmenopausal women, leptin and adiponectin concentrations are substantially correlated with sex hormone and SHBG concentrations regardless of obesity status.

Clinical effects of selective estrogen receptor modulators on vulvar and vaginal atrophy

OBJECTIVE

Vaginal estrogen therapy at the lowest effective dose is generally recommended for the treatment of vulvar and vaginal atrophy (VVA), but not all women are candidates. Selective estrogen receptor modulators (SERMs) aim to elicit specific positive effects on targeted tissues with neutral or minimal negative effects on other tissues. This review compares the vaginal effects of currently available and investigational SERMs.

METHODS

Relevant English-language articles published between 1980 and 2012 were identified through the PubMed database (search string "[Selective Estrogen Receptor Modulator OR SERM] AND [Vulvar OR Vaginal] AND Atrophy"), article reference lists, and EMBASE searches for individual SERMs. Both authors reviewed all articles, which formed the basis of this narrative literature review.

RESULTS

Activity profiles of SERMs in various tissues are distinct. Tamoxifen and arzoxifene have no specific positive vaginal effects but have reported variable or adverse gynecologic effects. Raloxifene does not improve VVA but can be used safely in combination with vaginal estrogen. Bazedoxifene has no demonstrated efficacy for VVA but, in combination with oral conjugated equine estrogens, improves the signs and symptoms of VVA. SERMs with positive vaginal effects (such as improvement in the vaginal maturation index, reduced vaginal pH, and improvement in the signs and symptoms of VVA) on postmenopausal symptomatic women include lasofoxifene (clinical development on hold) and ospemifene, which was recently approved for the treatment of VVA-related dyspareunia, with a class effect warning of potential venous thrombosis risk.

CONCLUSIONS

SERMs that specifically target the pathophysiology underlying VVA may provide an alternative to vaginal or systemic estrogen therapy.

Endogenous sex hormones and breast density in young women

BACKGROUND

Breast density is a strong risk factor for breast cancer and reflects epithelial and stromal content. Breast tissue is particularly sensitive to hormonal stimuli before it fully differentiates following the first full-term pregnancy. Few studies have examined associations between sex hormones and breast density among young women.

METHODS

We conducted a cross-sectional study among 180 women ages 25 to 29 years old who participated in the Dietary Intervention Study in Children 2006 Follow-up Study. Eighty-five percent of participants attended a clinic visit during their luteal phase of menstrual cycle. Magnetic resonance imaging measured the percentage of dense breast volume (%DBV), absolute dense breast volume (ADBV), and absolute nondense breast volume (ANDBV). Multiple-linear mixed-effect regression models were used to evaluate the association of sex hormones and sex hormone-binding globulin (SHBG) with %DBV, ADBV, and ANDBV.

RESULTS

Testosterone was significantly positively associated with %DBV and ADBV. The multivariable geometric mean of %DBV and ADBV across testosterone quartiles increased from 16.5% to 20.3% and from 68.6 to 82.3 cm(3), respectively (Ptrend ≤ 0.03). There was no association of %DBV or ADBV with estrogens, progesterone, non-SHBG-bound testosterone, or SHBG (Ptrend ≥ 0.27). Neither sex hormones nor SHBG was associated with ANDBV except progesterone; however, the progesterone result was nonsignificant in analysis restricted to women in the luteal phase.

CONCLUSIONS

These findings suggest a modest positive association between testosterone and breast density in young women.

IMPACT

Hormonal influences at critical periods may contribute to morphologic differences in the breast associated with breast cancer risk later in life.