High dehydroepiandrosterone-sulfate predicts breast cancer progression during new aromatase inhibitor therapy and stimulates breast cancer cell growth in tissue culture: a renewed role for adrenalectomy

Phase II trial of fulvestrant plus enzalutamide in ER+/HER2- advanced breast cancer

This clinical trial combined fulvestrant with the anti-androgen enzalutamide in women with metastatic ER+/HER2- breast cancer (BC). Eligible patients were women with ECOG 0-2, ER+/HER2- measurable or evaluable metastatic BC. Prior fulvestrant was allowed. Fulvestrant was administered at 500 mg IM on days 1, 15, 29, and every 4 weeks thereafter. Enzalutamide was given at 160 mg po daily. Fresh tumor biopsies were required at study entry and after 4 weeks of treatment. The primary efficacy endpoint of the trial was the clinical benefit rate at 24 weeks (CBR24). The median age was 61 years (46-87); PS 1 (0-1); median of 4 prior non-hormonal and 3 prior hormonal therapies for metastatic disease. Twelve had prior fulvestrant, and 91% had visceral disease. CBR24 was 25% (7/28 evaluable). Median progression-free survival (PFS) was 8 weeks (95% CI: 2-52). Adverse events were as expected for hormonal therapy. Significant (p < 0.1) univariate relationships existed between PFS and ER%, AR%, and PIK3CA and/or PTEN mutations. Baseline levels of phospho-proteins in the mTOR pathway were more highly expressed in biopsies of patients with shorter PFS. Fulvestrant plus enzalutamide had manageable side effects. The primary endpoint of CBR24 was 25% in heavily pretreated metastatic ER+/HER2- BC. Short PFS was associated with activation of the mTOR pathway, and PIK3CA and/or PTEN mutations were associated with an increased hazard of progression. Thus, a combination of fulvestrant or other SERD plus AKT/PI3K/mTOR inhibitor with or without AR inhibition warrants investigation in second-line endocrine therapy of metastatic ER+ BC.

Quantification of BNN27, a novel neuroprotective 17-spiroepoxy dehydroepiandrosterone derivative in the blood and retina of rodents, after single intraperitoneal administration

BNN27 is a novel 17‐spiroepoxy derivative of the neurosteroid Dehydroepiandrosterone with neuroprotective properties. The purpose of this study was the detection and quantification of BNN27 after single intraperitoneal administration, in the serum and retina of normal rodents. Forty‐two C57BL/6 mice and 48 Sprague–Dawley rats were used for the quantification of BNN27 in the blood serum and retina, respectively. BNN27 was injected intraperitoneally (i.p.) at concentrations of 100 and 30 mg/kg of body weight (b.w.), respectively. The blood was collected with retro‐orbital bleeding and the retina was isolated after enucleation at various time points. The molecule concentrations were measured with Liquid chromatography‐mass spectrometry (LC‐MS). Non‐compartmental analysis was used to determine pharmacokinetic parameters. BNN27 was found to have an elimination constant k_el = 0.465 h⁻¹ and mean residence time (MRT) 2.154 h in the mouse serum. The maximum concentration (C_max) in the retina was detected at 2 h (tCmax) after intraperitoneal administration and was equal to 1100 ng/g. BNN27 is rapidly eliminated from both blood and retina. In the retina specifically, it is undetectable 6 h after injection. BNN27 shows a rapid systemic elimination as anticipated by its small size and lipophilicity. It is measurable in small peripheral tissues such as the rat retina, after one single i.p. injection, using a simple method such as LC‐MS. Its detection in the retina corroborates the existing biological data that the molecule crosses the blood–retinal barrier, highlighting it as a potential neuroprotective agent for retinal disease.

Harnessing a Different Dependency: How to Identify and Target Androgen Receptor-Positive Versus Quadruple-Negative Breast Cancer

The androgen receptor (AR) is a promising therapeutic target for a subset of triple-negative breast cancers (TNBCs) in which AR is expressed. However, the mechanistic action of AR and the degree to which primary and metastatic tumors depend on AR, both before and after conventional treatment, remain to be defined. We discuss preclinical and clinical data for AR+ TNBC, the difficulties in monitoring AR protein levels, new methods for determining AR status, the influence of AR on "stemness" in the context of TNBC, the role of combined inhibition of sex steroid production and AR, and the role of AR in regulation of the immune system. Although the exact role of AR in subsets of TNBC is still being characterized, new therapies that target AR and the production of androgens may provide additional options for patients with TNBC for whom chemotherapy is currently the sole treatment option.

IPET study: an FLT-PET window study to assess the activity of the steroid sulfatase inhibitor irosustat in early breast cancer

BACKGROUND

Steroid sulfatase (STS) is involved in oestrogen biosynthesis and irosustat is a first generation, irreversible steroid sulfatase inhibitor. A pre-surgical window-of-opportunity study with irosustat was undertaken in estrogen receptor-positive (ER+) breast cancer to assess the effect of irosustat on tumour cell proliferation as measured by 3'-deoxy-3'-[18F] fluorothymidine uptake measured by PET scanning (FLT-PET) and Ki67.

METHODS

Postmenopausal women with untreated ER+ early breast cancer were recruited, and imaged with FLT-PET at baseline and after at least 2 weeks treatment with irosustat, 40 mg once daily orally. The primary endpoint was changed in FLT uptake; secondary endpoints included safety and tolerability of irosustat, changes in tumoral Ki67 and steroidogenic enzymes expression and circulating steroid hormone levels.

RESULTS

Thirteen women were recruited, and ten started irosustat for 2 weeks, followed by repeat FLT-PET scans in eight. Defining response as decreases of ≥20% in standardized uptake value (SUV) or ≥30% in Ki, 1 (12.5% (95% CI 2-47%, p = 0.001)) and 3 (43% (95% CI 16-75%, p = <0.001) patients, respectively, responded. 6 out of 7 patients had a Ki67 reduction (range = -19.3 to 76.4%), and median percentage difference in Ki67 was 52.3% (p = 0.028). In one patient with a low baseline STS expression, a 19.7% increase in Ki67 was recorded. STS decreases were seen in tumours with high basal STS expression, significant decreases were also noted in aromatase, and 17β-hydroxysteroid dehydrogenase type 1 and 2. Irosustat was generally well tolerated with all adverse event CTCAE Grade ≤2.

CONCLUSIONS

Irosustat resulted in a significant reduction in FLT uptake and Ki67, and is well tolerated. These data are the first demonstrating clinical activity of irosustat in early breast cancer. Baseline expression of STS may be a biomarker of sensitivity to irosustat.

Androgen receptor in estrogen receptor positive breast cancer: Beyond expression

In recent years, new therapeutic approaches have reshaped the overall strategy of breast cancer (BC) treatment and have markedly improved patient survival. This is, in part, due to novel therapies for estrogen receptor (ER)-positive BC. Unfortunately, many patients present de novo resistance to these therapies or develop an acquired resistance over time. Therefore, research is now focused on discovering new molecular targets to overcome these resistances. Interestingly, preclinical and clinical studies have shown a critical role for the cross-talk between androgen receptor (AR) and ER in luminal-like BC. AR is expressed in >60% of BC and in up to 90% of ERα-positive tumors. Multiple studies suggest that AR is associated with a favorable prognosis. However, AR overexpression and, in particular, the high AR:ER ratio, seem to be involved in resistance to hormonal treatment. In this setting, a group of BCs could benefit from AR-inhibitors; nevertheless, some ER-positive BC patients do not seem to benefit from this strategy. Therefore, it is crucial to identify biomarkers that would enable the selection of patients who might benefit from combination treatment with ER and AR inhibitors.

IRIS study: a phase II study of the steroid sulfatase inhibitor Irosustat when added to an aromatase inhibitor in ER-positive breast cancer patients

PURPOSE

Irosustat is a first-generation, orally active, irreversible steroid sulfatase inhibitor. We performed a multicentre, open label phase II trial of the addition of Irosustat to a first-line aromatase inhibitor (AI) in patients with advanced BC to evaluate the safety of the combination and to test the hypothesis that the addition of Irosustat to AI may further suppress estradiol levels and result in clinical benefit.

EXPERIMENTAL DESIGN

Postmenopausal women with ER-positive locally advanced or metastatic breast cancer who had derived clinical benefit from a first-line AI and who subsequently progressed were enrolled. The first-line AI was continued and Irosustat (40 mg orally daily) added. The primary endpoint was clinical benefit rate (CBR). Secondary endpoints included safety, tolerability, and pharmacodynamic end points.

RESULTS

Twenty-seven women were recruited, four discontinued treatment without response assessment. Based on local reporting, the CBR was 18.5% (95% CI 6.3-38.1%) on an intent to treat basis, increasing to 21.7% (95% CI 7.4-43.7%) by per-protocol analysis. In those patients that achieved clinical benefit (n = 5), the median (interquartile range) duration was 9.4 months (8.1-11.3) months. The median progression-free survival time was 2.7 months (95% CI 2.5-4.6) in both the ITT and per-protocol analyses. The most frequently reported grade 3/4 toxicities were dry skin (28%), nausea (13%), fatigue (13%), diarrhoea (8%), headache (7%), anorexia (7%) and lethargy (7%).

CONCLUSIONS

The addition of Irosustat to aromatase inhibitor therapy resulted in clinical benefit with an acceptable safety profile. The study met its pre-defined success criterion by both local and central radiological assessments.

Phase 1b study of orteronel in postmenopausal women with hormone-receptor positive (HR+) metastatic breast cancer

Introduction Suppressing both androgens and estrogens may circumvent hormone receptor resistance in breast cancer by reducing androgen receptor stimulation. Selective inhibition of the 17, 20-lyase enzyme by orteronel leads to decreased androgen production in men and would be anticipated to reduce estrogen and androgen production in women. Thus, we conducted a phase 1b study of orteronel in postmenopausal women with hormone-receptor positive (HR+) metastatic breast cancer. Methods The primary objective was to identify the recommended phase 2 dose (R2PD) of orteronel in women; escalation was via standard 3 + 3 design. The initial dose was 300 mg BID and escalated to 400 mg BID. Cycle length was 28 days. Enrolled patients had HR+ metastatic breast cancer and were evaluated every 8 weeks for disease progression. Results Eight heavily pre-treated women enrolled [median age: 57 yo (range 47-73)]. Four received 300 mg BID at dose level 1; 4 received 400 mg BID at dose level 2. No dose limiting toxicities (DLTs) were observed. Adverse events (AE) at least possibly related to orteronel included grade 1-2 nausea (n = 4) and bone pain (n = 3), and grade 1 hypokalemia, hot flashes, myalgia and AST elevation (n = 2). The only grade 3 AE was hypertension (n = 2) with 8 patients receiving 34 cycles of treatment. No objective responses were seen; clinical benefit was seen in 2 patients with stable disease for more than 6 months. Serum estrogens and testosterone were suppressed from baseline on both doses of orteronel. Conclusions Orteronel 400 mg BID is well tolerated in postmenopausal women, and significantly suppresses serum estrogens and testosterone. Clinical benefit was seen among heavily pretreated postmenopausal women with HR+ metastatic breast cancer.

Cooperative Dynamics of AR and ER Activity in Breast Cancer

Androgen receptor (AR) is expressed in 90% of estrogen receptor alpha-positive (ER⁺) breast tumors, but its role in tumor growth and progression remains controversial. Use of two anti-androgens that inhibit AR nuclear localization, enzalutamide and MJC13, revealed that AR is required for maximum ER genomic binding. Here, a novel global examination of AR chromatin binding found that estradiol induced AR binding at unique sites compared with dihydrotestosterone (DHT). Estradiol-induced AR-binding sites were enriched for estrogen response elements and had significant overlap with ER-binding sites. Furthermore, AR inhibition reduced baseline and estradiol-mediated proliferation in multiple ER⁺/AR⁺ breast cancer cell lines, and synergized with tamoxifen and fulvestrant. In vivo, enzalutamide significantly reduced viability of tamoxifen-resistant MCF7 xenograft tumors and an ER⁺/AR⁺ patient-derived model. Enzalutamide also reduced metastatic burden following cardiac injection. Finally, in a comparison of ER⁺/AR⁺ primary tumors versus patient-matched local recurrences or distant metastases, AR expression was often maintained even when ER was reduced or absent. These data provide preclinical evidence that anti-androgens that inhibit AR nuclear localization affect both AR and ER, and are effective in combination with current breast cancer therapies. In addition, single-agent efficacy may be possible in tumors resistant to traditional endocrine therapy, as clinical specimens of recurrent disease demonstrate AR expression in tumors with absent or refractory ER.

IMPLICATIONS

This study suggests that AR plays a previously unrecognized role in supporting E2-mediated ER activity in ER⁺/AR⁺ breast cancer cells, and that enzalutamide may be an effective therapeutic in ER⁺/AR⁺ breast cancers. Mol Cancer Res; 14(11); 1054-67. ©2016 AACR.

Impacts of smoking on endocrine treatment response in a prospective breast cancer cohort

BACKGROUND

The association between smoking and breast cancer prognosis remains unclear. The purpose of this study was to investigate whether preoperative smoking was associated with prognosis in different treatment groups.

METHODS

This population-based cohort consisted of 1065 breast cancer patients without preoperative treatment included between 2002 and 2012 in Lund, Sweden. Smoking status was examined in relation to patient and tumour characteristics, and prognosis in different treatment groups.

RESULTS

At the preoperative visit, 21.0% smoked. Median follow-up time was 5.1 years. Overall, in the 1016 patients included in the survival analyses, there was no significant association between smoking and risk of breast cancer events (adjusted hazard ratio (adjHR): 1.45; 95% confidence interval (CI): 0.95-2.20). For the 309 aromatase inhibitor (AI)-treated patients ⩾50 years with oestrogen receptor-positive (ER+) tumours, smoking was associated with risk of breast cancer events (adjHR: 2.97; 95% CI: 1.44-6.13), distant metastasis (adjHR: 4.19; 95% CI: 1.81-9.72), and death (adjHR: 3.52; 95% CI: 1.59-7.81). Smoking was not associated with breast cancer events or distant metastasis in other treatment groups.

CONCLUSIONS

Preoperative smoking was only associated with an increased risk for breast cancer events and distant metastasis in AI-treated patients. If confirmed, smoking status should be taken into consideration when selecting an endocrine therapy.

Nipple Aspirate Fluid Hormone Concentrations and Breast Cancer Risk

Prior reports identify higher serum concentrations of estrogens and androgens as risk factors for breast cancer, but steroids in nipple aspirate fluid (NAF) may be more related to risk. Incident breast cancer cases and mammography controls were recruited. Sex steroids were measured in NAF from the unaffected breasts of cases and one breast of controls. Menopausal status and menstrual cycle phase were determined. NAF steroids were purified by HPLC and quantified by immunoassays. Conditional logistic regression models were used to examine associations between NAF hormones and case-control status. NAF samples from 160 cases and 157 controls were evaluable for hormones. Except for progesterone and dehydroepiandrosterone (DHEA), the NAF and serum concentrations were not significantly correlated. NAF estradiol and estrone were not different between cases and controls. Higher NAF (but not serum) DHEA concentrations were associated with cases, particularly among estrogen receptor (ER)-positive cases (NAF odds ratio (OR) = 1.18, 95 % confidence interval (CI) 1.02, 1.36). NAF DHEA was highly correlated with NAF estradiol and estrone but not with androstenedione or testosterone. Higher progesterone concentrations in both NAF and serum were associated with a lower risk of ER-negative cancer (NAF OR = 0.69, 95 % CI 0.51, 0.92). However, this finding may be explained by case-control imbalance in the number of luteal phase subjects (2 cases and 19 controls). The significantly higher concentration of DHEA in NAF of cases and its correlation with NAF estradiol indicates a potentially important role of this steroid in breast cancer risk; however, the negative association of progesterone with risk is tentative.

Estrone sulfate and dehydroepiandrosterone sulfate: Transactivation of the estrogen and androgen receptor

Dehydroepiandrosterone sulfate (DHEAS) and estrone sulfate (E1S) are two of the most abundant steroids in the human circulation. The enzyme steroid sulfatase (STS) cleaves the sulfate group of DHEAS and E1S leading to biosynthesis of endogenous hormones such as testosterone and estrone. In the current study we aimed at determining the effect of E1S and DHEAS on estrogen receptor (ER) and androgen receptor (AR) transactivation. Using luciferase reporter gene assays, the ER and AR transactivities of E1S and DHEAS were determined by direct cell exposure; as well as upon extraction from human serum using a method to extract perfluorinated alkyl acids (PFAAs). By direct cell exposure, both E1S and DHEAS transactivated the ER and the AR in dose-dependent manners. The DHEAS-induced AR transactivity could be abolished by the STS inhibitor STX64. Immunoassay analysis confirmed the presence of E1S and DHEAS in the serum PFAA extracts with mean recoveries below 2.5%. For the PFAA extracts of human male and female serum, only the AR was significantly transactivated. The AR transactivity of the sulfated steroids in the extracts was abolished by STX64 to obtain the net PFAA induced xenohormone transactivity, but further cleanup might be needed at high concentrations of E1S.

Targeting the androgen receptor in prostate and breast cancer: several new agents in development

Prostate cancer (PCa) and breast cancer (BCa) share similarities as hormone-sensitive cancers with a wide heterogeneity of both phenotype and biology. The androgen receptor (AR) is a hormone receptor involved in both benign and malignant processes. Targeting androgen synthesis and the AR pathway has been and remains central to PCa therapy. Recently, there has been increased interest in the role of the AR in BCa development and growth, with results indicating AR co-expression with estrogen, progesterone, and human epidermal growth factor receptors, across all intrinsic subtypes of BCa. Targeting the AR axis is an evolving field with novel therapies in development which may ultimately be applicable to both tumor types. In this review, we offer an overview of available agents which target the AR axis in both PCa and BCa and provide insights into the novel drugs in development for targeting this signaling pathway.

Dehydroepiandrosterone for women in the peri- or postmenopausal phase

BACKGROUND

During menopause a decreasing ovarian follicular response generally causes a fluctuation and eventual decrease in estrogen levels. This can lead to the development of various perimenopausal and postmenopausal symptoms (for example hot flushes, night sweats, vaginal dryness). Dehydroepiandrosterone (DHEA) is one of the main precursors of androgens, which in turn are converted to testosterone and estrogens. It is possible that the administration of DHEA may increase estrogen and testosterone levels in peri- and postmenopausal women to alleviate their symptoms and improve general wellbeing and sexual function (for example libido, dyspareunia, satisfaction). Treatment with DHEA is controversial as there is uncertainty about its effectiveness and safety. This review should clearly outline the evidence for DHEA in the treatment of menopausal symptoms and evaluate its effectiveness and safety by combining the results of randomised controlled trials.

OBJECTIVES

To assess the effectiveness and safety of administering DHEA to women with menopausal symptoms in the peri- or postmenopausal phase.

SEARCH METHODS

The databases that we searched (3 June 2014) with no language restrictions applied were the Cochrane Menstrual Disorders and Subfertility Group Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, PsycINFO, CINAHL and LILACS. We also searched conference abstracts and citation lists in the ISI Web of Knowledge. Ongoing trials were searched in the trials registers. Reference lists of retrieved articles were checked.

SELECTION CRITERIA

We included randomised controlled trials comparing any dose and form of DHEA by any route of administration versus any other active intervention, placebo or no treatment for a minimal treatment duration of seven days in peri- and postmenopausal women.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data after assessing eligibility for inclusion and quality of studies. Authors were contacted for additional information.

MAIN RESULTS

Twenty-eight trials with 1273 menopausal women were included in this review. Data could be extracted from 16 trials to conduct the meta-analysis. The overall quality of the studies was moderate to low with the majority of studies that were included in the meta-analysis having reasonable methodology. Compared to placebo, DHEA did not improve quality of life (standardised mean difference (SMD) 0.16, 95% confidence interval (CI) -0.03 to 0.34, P = 0.10, 8 studies, 287 women (132 from parallel and 155 from crossover trials), I² = 0%, moderate quality evidence; one trial of the nine that reported on this outcome was removed in a sensitivity analysis as it was judged to be at high risk of bias). DHEA was found to be associated with androgenic side effects (mainly acne) (odds ratio (OR) 3.77, 95% CI 1.36 to 10.4, P = 0.01, 5 studies, 376 women, I² = 10%, moderate quality evidence) when compared to placebo. No associations were found with other adverse effects. It was unclear whether DHEA affected menopausal symptoms as the results from the trials were inconsistent and could not easily be pooled to provide an overall effect due to different types of measurement (for example continuous, dichotomous, change and end scores). DHEA was found to improve sexual function (SMD 0.31, 95% CI 0.07 to 0.55, P = 0.01, 5 studies, 261 women (239 women from parallel trials and 22 women from crossover trials), I² = 0%; one trial judged to be at high risk of bias was removed during sensitivity analysis) compared to placebo.There was no difference in the acne associated with DHEA when comparing studies that used oral DHEA (OR 2.16, 95% CI 0.47 to 9.96, P = 0.90, 3 studies, 136 women, I² = 5%, very low quality evidence) to one study that used skin application of DHEA (OR 2.74, 95% CI 0.10 to 74.87, P = 0.90, 1 study, 22 women, very low quality evidence). The effects did not differ for sexual function when studies using oral DHEA (SMD 0.11, 95% CI -0.13 to 0.35, P = 0.36, 5 studies, 340 women, I² = 0) were compared to a study using intravaginal DHEA (SMD 0.42, 95% CI 0.03 to 0.81, 1 study, 218 women). Test for subgroup differences: Chi² = 1.77, df = 1 (P = 0.18), I² = 43.4%. Insufficient data were available to assess quality of life and menopausal symptoms for this comparison.There were insufficient data available to compare the effects of DHEA to hormone therapy (HT) for quality of life, menopausal symptoms, and adverse effects. No large differences in treatment effects were found for sexual function when comparing DHEA to HT (mean difference (MD) 1.26, 95% CI -0.21 to 2.73, P = 0.09, 2 studies, 41 women, I² = 0%).

AUTHORS' CONCLUSIONS

There is no evidence that DHEA improves quality of life but there is some evidence that it is associated with androgenic side effects. There is uncertainty whether DHEA decreases menopausal symptoms, but DHEA may slightly improve sexual function compared with placebo.

Effects of aromatase inhibitors and body mass index on steroid hormone levels in women with early and advanced breast cancer

BACKGROUND

Aromatase inhibitors (AIs) are central to the management of oestrogen receptor-positive breast cancer in the adjuvant and metastatic setting. Levels of circulating steroid hormones (SHs) were measured in patients established on AIs to investigate: the influence of body mass index (BMI) in both the adjuvant and metastatic setting; the class of AI utilized in the adjuvant setting (steroidal versus non-steroidal); and differences in SH levels between women treated adjuvantly and those receiving a second-line AI for locally advanced/metastatic disease.

METHODS

Plasma levels of androstenedione, 5-androstene-3β,17β-diol, dehydroepiandrosterone, oestradiol and testosterone were measured by radioimmunoassay in women with breast cancer who were receiving AIs in either an adjuvant or a metastatic setting. Differences between mean SH levels by class of AI, BMI, and second-line versus adjuvant therapy were assessed.

RESULTS

Sixty-four women were receiving AI therapy, 45 (70 per cent) in an adjuvant setting and 19 (30 per cent) were taking a second-line AI. There was no significant correlation between BMI and SH levels. However, BMI was significantly higher in the second-line AI cohort compared with the adjuvant cohort (29.8 versus 26.2 kg/m2 respectively; P = 0.026). In the adjuvant setting, patients receiving a steroidal AI had significantly higher levels of all five hormones (P < 0.050). In the second-line AI cohort, oestradiol levels were significantly higher than in the adjuvant cohort (4.5 versus 3.3 pg/ml respectively; P = 0.022). Multivariable analysis adjusted for BMI confirmed the higher residual oestradiol level in the second-line AI group (P = 0.063) and a significantly higher androstenedione level (P = 0.022).

CONCLUSION

Residual levels of SH were not significantly influenced by BMI. However, the significant differences in residual SH levels between the second-line and adjuvant AI cohort is of relevance in the context of resistance to AI therapy, and warrants further investigation.

Breast cancer: current and future endocrine therapies

Endocrine therapy forms a central modality in the treatment of estrogen receptor positive breast cancer. The routine use of 5 years of adjuvant tamoxifen has improved survival rates for early breast cancer, and more recently has evolved in the postmenopausal setting to include aromatase inhibitors. The optimal duration of adjuvant endocrine therapy remains an active area of clinical study with recent data supporting 10 years rather than 5 years of adjuvant tamoxifen. However, endocrine therapy is limited by the development of resistance, this can occur by a number of possible mechanisms and numerous studies have been performed which combine endocrine therapy with agents that modulate these mechanisms with the aim of preventing or delaying the emergence of resistance. Recent trial data regarding the combination of the mammalian target of rapamycin (mTOR) inhibitor, everolimus with endocrine therapy have resulted in a redefinition of the clinical treatment pathway in the metastatic setting. This review details the current endocrine therapy utilized in both early and advanced disease, as well as exploring potential new targets which modulate pathways of resistance, as well as agents which aim to modulate adrenal derived steroidogenic hormones.

Role of the androgen receptor in breast cancer and preclinical analysis of enzalutamide

Introduction

The androgen receptor (AR) is widely expressed in breast cancers and has been proposed as a therapeutic target in estrogen receptor alpha (ER) negative breast cancers that retain AR. However, controversy exists regarding the role of AR, particularly in ER + tumors. Enzalutamide, an AR inhibitor that impairs nuclear localization of AR, was used to elucidate the role of AR in preclinical models of ER positive and negative breast cancer.

Methods

We examined nuclear AR to ER protein ratios in primary breast cancers in relation to response to endocrine therapy. The effects of AR inhibition with enzalutamide were examined in vitro and in preclinical models of ER positive and negative breast cancer that express AR.

Results

In a cohort of 192 women with ER + breast cancers, a high ratio of AR:ER (≥2.0) indicated an over four fold increased risk for failure while on tamoxifen (HR = 4.43). The AR:ER ratio had an independent effect on risk for failure above ER % staining alone. AR:ER ratio is also an independent predictor of disease-free survival (HR = 4.04, 95% CI: 1.68, 9.69; p = 0.002) and disease specific survival (HR = 2.75, 95% CI: 1.11, 6.86; p = 0.03). Both enzalutamide and bicalutamide inhibited 5-alpha-dihydrotestosterone (DHT)-mediated proliferation of breast cancer lines in vitro; however, enzalutamide uniquely inhibited estradiol (E2)-mediated proliferation of ER+/AR + breast cancer cells. In MCF7 xenografts (ER+/AR+) enzalutamide inhibited E2-driven tumor growth as effectively as tamoxifen by decreasing proliferation. Enzalutamide also inhibited DHT- driven tumor growth in both ER positive (MCF7) and negative (MDA-MB-453) xenografts, but did so by increasing apoptosis.

Conclusions

AR to ER ratio may influence breast cancer response to traditional endocrine therapy. Enzalutamide elicits different effects on E2-mediated breast cancer cell proliferation than bicalutamide. This preclinical study supports the initiation of clinical studies evaluating enzalutamide for treatment of AR⁺ tumors regardless of ER status, since it blocks both androgen- and estrogen- mediated tumor growth.

Effect of an investigational CYP17A1 inhibitor, orteronel (TAK-700), on estrogen- and corticoid-synthesis pathways in hypophysectomized female rats and on the serum estradiol levels in female cynomolgus monkeys

Orteronel (TAK-700) is an investigational, non-steroidal inhibitor of CYP17A1 with preferential inhibition of 17,20-lyase in NCI-H295 cells. Estrogen is synthesized from androgen by aromatase activity, and the effect of orteronel on estrogen synthesis was therefore evaluated. First, it was confirmed that orteronel does not directly inhibit aromatase activity. Second, the specific decline of serum estradiol and androgen levels in hypophysectomized female rats by orteronel in comparison with aromatase inhibitor anastrozole was evaluated; orteronel at doses ≥3mg/kg significantly suppressed serum estradiol, testosterone, androstenedione and 17-hydroxyprogesterone levels, and increased progesterone levels in the estrogen-synthesis pathway. Orteronel, at a dose of 300mg/kg, suppressed serum estradiol concentrations to a similar degree as 0.1mg/kg anastrozole. In contrast, in the corticoid-synthesis pathway, serum aldosterone, corticosterone, and progesterone levels did not change significantly following administration of 300mg/kg of orteronel. Third, the effect of multiple oral administration of orteronel on serum estradiol levels in regularly cycling female cynomolgus monkeys was evaluated. Orteronel at 15mg/kg/day (7.5mg/kg/treatment, twice daily [bid]) continued to suppress the estradiol surge prior to the start of luteal phase for 1.5-times the average duration of three consecutive, pre-treatment menstrual cycles, while serum progesterone was maintained at levels almost equal to those in the luteal phase although a certain portion of this increased level of progesterone could be of adrenal-origin. This suppressive effect on estradiol surge was thought to be reversible since serum estradiol levels started to rise immediately after the discontinuation of orteronel. Estradiol surge was not abrogated by treatment with anastrozole 0.2mg/kg/day (0.1mg/kg/treatment, bid). In summary, orteronel can suppress serum estradiol concentrations in hypophysectomized female rats and monkeys through selective inhibition of CYP17A1 activity, suggesting that orteronel might be effective for hormone-dependent breast cancers and estrogen-dependent diseases.

Membrane transporters for sulfated steroids in the human testis--cellular localization, expression pattern and functional analysis

Sulfated steroid hormones are commonly considered to be biologically inactive metabolites, but may be reactivated by the steroid sulfatase into biologically active free steroids, thereby having regulatory function via nuclear androgen and estrogen receptors which are widespread in the testis. However, a prerequisite for this mode of action would be a carrier-mediated import of the hydrophilic steroid sulfate molecules into specific target cells in reproductive tissues such as the testis. In the present study we detected predominant expression of the Sodium-dependent Organic Anion Transporter (SOAT), the Organic Anion Transporting Polypeptide 6A1, and the Organic Solute Carrier Partner 1 in human testis biopsies. All of these showed significantly lower or even absent mRNA expression in severe disorders of spermatogenesis (arrest at the level of spermatocytes or spermatogonia, Sertoli cell only syndrome). Only SOAT was significantly lower expressed in biopsies showing hypospermatogenesis. By use of immunohistochemistry SOAT was localized to germ cells at various stages in human testis biopsies showing normal spermatogenesis. SOAT immunoreactivity was detected in zygotene primary spermatocytes of stage V, pachytene spermatocytes of all stages (I–V), secondary spermatocytes of stage VI, and round spermatids (step 1 and step 2) in stages I and II. Furthermore, SOAT transport function for steroid sulfates was analyzed with a novel liquid chromatography tandem mass spectrometry procedure capable of profiling steroid sulfate molecules from cell lysates. With this technique, the cellular inward-directed SOAT transport was verified for the established substrates dehydroepiandrosterone sulfate and estrone-3-sulfate. Additionally, β-estradiol-3-sulfate and androstenediol-3-sulfate were identified as novel SOAT substrates.

Postmenopausal breast cancer, androgens, and aromatase inhibitors

Recent data can help to better define the long debated relationship between androgens and breast cancer (BC) after menopause. We reviewed the available literature data on: the origin of androgens after menopause, the association between circulating androgens and BC incidence and recurrence, the relationship between circulating and intratumoral hormones, the prognostic significance of the presence of androgen receptors (ARs) in the different BC subtypes, the androgen effect on BC cell lines, and the relationship between androgens and aromatase inhibitors. Epidemiological, clinical, and preclinical data on the role of androgens and of ARs on estrogen receptor (ER)-negative BC are somewhat controversial. However, most preclinical studies suggest that activated ARs, when present, have a proliferative effect, particularly in HER2 expressing cell lines, due to the cross-talk between AR and HER2 pathways. As regards ER-positive BC, epidemiological studies associate androgen levels with increased incidence and risk of recurrences, whilst clinical studies associate the AR positivity with a better prognosis. Preclinical studies suggest that the action of androgens is bidirectional: mainly proliferative, because circulating androgens are the precursors of estrogens, but also anti-proliferative, because AR activation restrains ER activity. The relative increase of androgenic action that follows the blocking of androgen aromatization into estrogens by aromatase inhibitors (AIs), could contribute to their therapeutic efficacy in AR-positive cases. Available data, although defining a complex picture, suggest that circulating androgen levels are clinically relevant, particularly when AIs are used.

Irosustat: a first-generation steroid sulfatase inhibitor in breast cancer

Endocrine therapy is a key modality in the management of breast cancer, with current options for postmenopausal women including tamoxifen, aromatase inhibitors and fulvestrant. Unfortunately, in spite of these advances, many women still relapse or progress on endocrine therapy. Given that resistance (de novo or acquired resistance) is a major limiting factor in the use of endocrine therapy, additional endocrine therapies with novel methods of action are required. Steroid sulfatase, which is responsible for the conversion of estrone sulfate to estrone, as well as dehydroepiandrosterone sulfate to dehydroepiandrosterone, has been implicated in endocrine resistance. In this article, we summarize the preclinical and clinical data to support the potential role of steroid sulfatase in breast cancer, as well as the current data on the first available steroid sulfatase inhibitor named irosustat (STX64; 667 Coumate; BN83495), and discuss its potential clinical development.

Steroid sulfatase: a pivotal player in estrogen synthesis and metabolism

Steroid sulfatase plays a pivotal role in regulating the formation of biologically active steroids from inactive steroid sulfates. It is responsible for the hydrolysis of estrone sulfate and dehydroepiandrosterone sulfate to estrone and dehydroepiandrosterone, respectively, both of which can be subsequently reduced to steroids with estrogenic properties (i.e. estradiol and androstenediol) that can stimulate the growth of tumors in hormone-responsive tissues of the breast, endometrium and prostate. Hence, the action of steroid sulfatase is implicated in physiological processes and pathological conditions. It has been five years since our group last reviewed the important role of this enzyme in steroid synthesis and the progress made in the development of potent inhibitors of this important enzyme target. This timely review therefore concentrates on recent advances in steroid sulfatase research, and summarises the findings of clinical trials with Irosustat (BN83495), the only steroid sulfatase inhibitor that is being trialed in postmenopausal women with breast or endometrial cancer.

Treatment of metastatic breast cancer: state-of-the-art, subtypes and perspectives

Current treatment of metastatic breast cancer (MBC) aims at achieving meaningful clinical responses, improved quality of life, long-term remissions, prolonged survival, and dares to hope for a cure in a small percentage of cases. This article will discuss both consensus and controversies in the management of MBC in the context of the new evolving breast cancer molecular classification. Hormonal therapy remains the mainstay of management of MBC Luminal A and B. Data is emerging on management of ErbB2-positive HR-positive MBC by combining hormonal manipulation and targeted anti-ErbB2 therapy and has recently received regulatory approval in Europe and USA. The optimal use and duration of single agent or combination chemotherapy is discussed. Data and controversies surrounding the use of newer agents such as nab-paclitaxel, ixabepilone, eribulin, and PARP inhibitors as well as trastuzumab is reviewed. Better understanding of pathophysiology has paved the way for the introduction of newer anti-ErbB2 agents such as lapatinib, pertuzumab, T-DM1 and neratinib. Controversies regarding bevacizumab and anti-angiogenesis are discussed. Bisphosphonates have significantly reduced skeletal related events and made significant improvements in the quality of life of patients with MBC. Newer anti-RANK Ligand antibodies show promising results. Significant advances in the understanding of molecular biology of breast cancer have been made and should lead to an improvement in the outcome of MBC. More possibilities of cure can become an attainable goal in the near future.

Association between alcohol intake and serum sex hormones and peptides differs by tamoxifen use in breast cancer survivors

OBJECTIVE

To measure the association between alcohol intake and 11 hormones and peptides in postmenopausal breast cancer survivors and to evaluate whether this association differs by tamoxifen use.

METHODS

Self-reported alcohol intake was assessed via food frequency questionnaire on average 30 months post-breast cancer diagnosis in 490 postmenopausal women from three western states. Concurrently, a fasting blood sample was obtained for assay of estrone, estradiol, free estradiol, testosterone, free testosterone, dehydroepiandrosterone sulfate (DHEAS), sex hormone-binding globulin (SHBG), leptin, C-peptide, insulin-like growth factor-I (IGF-I), and IGF-binding protein-3. Adjusted means of these hormones and peptides were calculated for categories of alcohol intake, overall and stratified by tamoxifen use.

RESULTS

The association between alcohol intake and serum hormone and peptide levels differed by tamoxifen use. We found statistically significant inverse associations between alcohol intake and both leptin and SHBG values but only among tamoxifen users. In women not using tamoxifen, we found a positive association between alcohol intake and DHEAS but no association in tamoxifen users.

CONCLUSION

Tamoxifen may modify the association between alcohol intake and serum hormones and peptides. The significant associations found for DHEAS and SHBG are in a direction considered unfavorable for breast cancer prognosis. Postmenopausal breast cancer survivors may benefit from decreasing their alcohol intake.

Molecular signatures of neoadjuvant endocrine therapy for breast cancer: characteristics of response or intrinsic resistance

Approximately 30% of patients with estrogen receptor (ER) positive breast cancers exhibit de novo or intrinsic resistance to endocrine therapies. The purpose of this study was to define genes that distinguish ER+ resistant from ER+ responsive tumors, prior to the start of hormone therapies. Previously untreated post-menopausal patients with ER+ breast cancers were treated for 4 months in a neoadjuvant setting with the aromatase inhibitor exemestane alone, or in combination with the antiestrogen tamoxifen. Matched pre- and post-treatment tumor samples from the same patient, were analyzed by gene expression profiling and were correlated with response to treatment. Genes associated with tumor shrinkage achieved by estrogen blockade therapy were identified, as were genes associated with resistance to treatment. Prediction Analysis of Microarrays (PAM) identified 50 genes that can predict response or intrinsic resistance to neoadjuvant endocrine therapy of ER+ tumors, 8 of which have been previously implicated as useful biomarkers in breast cancer. In summary, we identify genes associated with response to endocrine therapy that may distinguish ER+, hormone responsive breast cancers, from ER+ tumors that exhibit intrinsic or de novo resistance. We suggest that the estrogen signaling pathway is aberrant in ER+ tumors with intrinsic resistance. Lastly, the studies show upregulation of a "lipogenic pathway" in non-responsive ER+ tumors that may serve as a marker of intrinsic resistance. This pathway may represent an alternative target for therapeutic intervention.

Lack of expression of androgen receptor may play a critical role in transformation from in situ to invasive basal subtype of high-grade ductal carcinoma of the breast

Androgen receptor has been implicated in the pathogenesis of breast carcinoma. In this study, we explored the potential role of androgen receptor in breast cancer by analyzing its expression using immunohistochemistry and its relationship with tumor progress (ductal carcinoma in situ [DCIS] versus invasive ductal carcinoma [IDC]); nuclear grades (high grade [HG] versus non-high grade); expression of estrogen receptor (ER), progesterone receptor (PR), HER-2; and 3 molecular classifications: cytokeratin classification, triple (ER/PR/HER-2) negative classification, and ER/HER-2 classification in 184 breast carcinomas. We found that (1) lack of androgen receptor expression was associated with HG-IDC and with basal subtypes of HG-IDC, suggesting androgen receptor may play an important role in preventing the invasive transformation in this subgroup of breast carcinoma. (2) HG-IDC and HG-DCIS more frequently expressed androgen receptor than ER (55%-93% for androgen receptor and 18%-30% for ER) and were frequently androgen receptor+/ER- (63% for HG-DCIS and 39% for HG-IDC), which made androgen receptor a possible therapeutic target. (3) One third of HG-IDC was negative for androgen receptor, ER, PR, and HER-2, suggesting that further studies are needed to identify other key molecules for targeted therapy. We purpose that androgen receptor should be routinely measured for breast cancer.

Pregnenolone sulfate in the brain: a controversial neurosteroid

Pregnenolone sulfate (PREGS) has been shown, either at high nanomolar or at micromolar concentrations, to increase neuronal activity by inhibiting GABAergic and by stimulating glutamatergic neurotransmission. PREGS is also a potent modulator of sigma type 1 (sigma1) receptors. It has been proposed that these actions of PREGS underlie its neuropharmacological effects, and in particular its influence on memory processes. On the other hand, the PREGS-mediated increase in neuronal excitability may become dangerous under particular conditions, for example in the case of excitotoxic stress or convulsions. However, the physiopathological significance of these observations has recently been put into question by the failure to detect significant levels of PREGS within the brain and plasma of rats and mice, either by direct analytical methods based on liquid chromatography/mass spectrometry (LC/MS) or enzyme linked immunosorbent assay (ELISA) with specific antibodies against PREGS, or by indirect gas chromatography/mass spectrometry (GC/MS) analysis with improved sample workup. These recent results have not come to the attention of a large number of neurobiologists interested in steroid sulfates. However, although available direct analytical methods have failed to detect levels of PREGS above 0.1-0.3 ng/g in brain tissue, it may be premature to completely exclude the local formation of biologically active PREGS within specific and limited compartments of the nervous system. In contrast to the situation in rodents, significant levels of sulfated 3beta-hydroxysteroids have been measured in human plasma and brain. Previous indirect measures of steroid sulfates by radioimmunoassays (RIA) or GC/MS had detected elevated levels of PREGS in rodent brain. The discrepancies between the results of different assay procedures have revealed the danger of indirect analysis of steroid sulfates. Indeed, PREGS must be solvolyzed/hydrolyzed prior to RIA or GC/MS analysis, and it is the released, unconjugated PREG which is then quantified. Extreme caution needs to be exercised during the preparation of samples for RIA or GC/MS analysis, because the fraction presumed to contain only steroid sulfates can be contaminated by nonpolar components from which PREG is generated by the solvolysis/hydrolysis/derivatization reactions.

A New Hormonal Therapy for Estrogen Receptor–Negative Breast Cancer

BACKGROUND

We postulate that the androgen dehydroepiandrosterone sulfate (DHEAS) may represent an innovative hormonal treatment for estrogen (ER), progesterone (PR) receptor-negative, but androgen receptor (AR)-positive breast cancers by inhibiting breast cancer cell growth through AR stimulation.

METHODS

Three ER,PR-negative breast cancer cell lines (HCC 1137, 1954, and 38), were treated with DHEAS. DHEAS-induced growth was measured by a methylthiotetrazole (MTT) proliferation assay and apoptosis by TUNEL fluorescence. Androgen receptor gene expression levels were determined using quantitative real-time polymerase chain reaction (q-RT-PCR).

RESULTS

HCC cell lines 1954 and 1937 were positive for AR expression; HCC 38 was weakly positive. MTT analysis showed DHEAS-induced decreases in cell proliferation of 47% in HCC 1937, 27% in HCC 1954, and 0.4% in HCC 38. Ten days of culturing HCC 1954 cells after the removal of DHEAS resulted in a 3.5-fold increase in growth. Continuous treatment for the same duration induced a 2.8-fold decrease in growth. Parallel experiments showed no significant changes in HCC 38 cultures. TUNEL assays showed DHEAS-induced apoptosis fold increases of 2.8 in HCC 1937, 1.9 in HCC 1954, and no significant difference in HCC 38 cultures. Q-RT-PCR of HCC 1954 cells showed a 6-fold DHEAS-induced decrease in AR gene expression at 4 h. Co-treatment with Casodex nullified this effect.

CONCLUSIONS

DHEAS inhibited growth of ER,PR-negative, AR-positive breast cancer cells. DHEAS was cytotoxic to these breast cancer cells via the apoptosis pathway. DHEAS may be an effective treatment for a population previously excluded from hormone therapy.

Steroid sulfatase in breast carcinoma and change of serum estrogens levels after operation

Fifty-four breast carcinomas were studied for the expression of steroid sulfatase (STS) by immunohistochemistry. Correlations between the expression of STS and clinical parameters were determined. Concentrations of serum estrone (E1), estrone sulfate (E1S), estradiol (E2) and estradiol sulfate (E2S) in 12 postmenopausal patients with STS positive tumor were measured by radioimmunoassay. Positive expression of STS was obtained in 72% of tumors. The incidence of STS positive tumor was significantly more frequent in postmenopausal patients (p = 0.01). In our postmenopausal patients, serum E1, E1S, E2, E2S and E2S levels in STS high score group were decreased postoperatively, and those in both STS high and low score group were stabilized after operation. Results from this study suggest STS in breast carcinoma may play an important enzyme of the intratumoral estrogen synthesis in postmenopausal women, and it would be interesting that locally produced STS might be closely related to the control of estrogens environment in breast carcinoma.

Phase I study of STX 64 (667 Coumate) in breast cancer patients: the first study of a steroid sulfatase inhibitor

PURPOSE

Inhibition of steroid sulfatase (STS), the enzyme responsible for the hydrolysis of steroid sulfates, represents a potential novel treatment for postmenopausal women with hormone-dependent breast cancer. Estrone and DHEA are formed by this sulfatase pathway and can be converted to steroids (estradiol and androstenediol, respectively), which have potent estrogenic properties.

EXPERIMENTAL DESIGN

STX64 (667 Coumate), a tricylic coumarin-based sulfamate that irreversibly inhibits STS activity, was selected for entry into the first phase I trial of a STS inhibitor in postmenopausal women with breast cancer. STX64 was administered orally (nine patients at 5 mg and five patients at 20 mg) as an initial dose followed 1 week later by 3 x 2 weekly cycles, with each cycle comprising daily dosing for 5 days followed by 9 days off treatment. Blood and tumor tissue samples were collected for the assessment of STS activity and serum was obtained for steroid hormone measurements before and after treatment.

RESULTS

The median inhibition of STS activity by STX64 was 98% in peripheral blood lymphocytes (PBL) and 99% in breast tumor tissue at the end of the 5-day dosing period. As expected, serum concentrations of estrone, estradiol, androstenediol, and DHEA all decreased significantly from pretreatment levels. Unexpectedly, androstenedione and testosterone concentrations also decreased. Four patients, all of whom had previously progressed on aromatase inhibitors, showed evidence of stable disease for 2.75 to 7 months. The drug was well tolerated with only minor drug-related adverse events recorded.

CONCLUSION

STX64 is a potent, well-tolerated STS inhibitor. It inhibits STS activity in PBLs and tumor tissues and causes significant decreases in serum concentrations of steroids with estrogenic properties.

Steroid sulfatase: molecular biology, regulation, and inhibition

Steroid sulfatase (STS) is responsible for the hydrolysis of aryl and alkyl steroid sulfates and therefore has a pivotal role in regulating the formation of biologically active steroids. The enzyme is widely distributed throughout the body, and its action is implicated in physiological processes and pathological conditions. The crystal structure of the enzyme has been resolved, but relatively little is known about what regulates its expression or activity. Research into the control and inhibition of this enzyme has been stimulated by its important role in supporting the growth of hormone-dependent tumors of the breast and prostate. STS is responsible for the hydrolysis of estrone sulfate and dehydroepiandrosterone sulfate to estrone and dehydroepiandrosterone, respectively, both of which can be converted to steroids with estrogenic properties (i.e., estradiol and androstenediol) that can stimulate tumor growth. STS expression is increased in breast tumors and has prognostic significance. The role of STS in supporting tumor growth prompted the development of potent STS inhibitors. Several steroidal and nonsteroidal STS inhibitors are now available, with the irreversible type of inhibitor having a phenol sulfamate ester as its active pharmacophore. One such inhibitor, 667 COUMATE, has now entered a phase I trial in postmenopausal women with breast cancer. The skin is also an important site of STS activity, and deficiency of this enzyme is associated with X-linked ichthyosis. STS may also be involved in regulating part of the immune response and some aspects of cognitive function. The development of potent STS inhibitors will allow investigation of the role of this enzyme in physiological and pathological processes.

Understanding the biologic mechanisms responsible for breast-cancer progression during tamoxifen or fulvestrant treatment

BACKGROUND

Dehydroepiandosterone sulfate (DHEAS) causes breast-cancer proliferation, even during tamoxifen or fulvestrant blockade. The purpose of this study was to determine possible mechanisms for this treatment failure.

METHODS

T-47D cells (estrogen receptor [ER] and progesterone receptor [PR] positive) were treated with fulvestrant (10 micromol/L), tamoxifen (10 mmol/L or 0.0001 nmol/L), or vehicle and stimulated with DHEAS. Gene expression of ER, PR, insulin-like growth factor (IGF)-1 and -2, and insulin-like growth-factor binding protein (IGFBP)-1 through -4 was determined.

RESULTS

ER and PR gene expression decreased by 1.3- and 4-fold with fulvestrant and DHEAS. ER expression decreased by 2.7-fold with 0.0001 nmol/L tamoxifen and DHEAS. ER and PR expression were unchanged by 10 nmol/L tamoxifen. IGF-1 and IGF-2 were not expressed. IGFBP-2 and -4 expression decreased by 1.9- and 1.6-fold after DHEAS stimulus, although this was not statistically significant.

CONCLUSIONS

DHEAS exposure, even in the presence of tamoxifen and fulvestrant, induces changes in ER and PR gene expression that may be partially responsible for breast cancer progression.

The proliferative effects of 5-androstene-3 beta,17 beta-diol and 5 alpha-dihydrotestosterone on cell cycle analysis and cell proliferation in MCF7, T47D and MDAMB231 breast cancer cell lines

Epidemiological studies suggest that precursor steroids are implicated in the aetiology of breast cancer. However, our understanding of the role of precursor steroids in breast cancer is complicated by fact that there are many precursor steroids, which are metabolically inter-related and have divergent proliferative activities on the growth of breast cancer cell lines. In this study the proliferative affects of 5 alpha-dihydrotestosterone and 5-androstene-3 beta,17 beta-diol, which may be considered true metabolites acting at a tissue level, on MCF7, T47D and MDAMB231 breast cancer cell lines have been examined by a flow cytometric technique. DNA cell cycle analysis demonstrates that 5-androstene-3 beta,17 beta-diol stimulates the proliferation of hormone-dependent cell lines at physiological levels by an oestrogen receptor mediated mechanism whereas 5 alpha-dihydrotestosterone does not affect the proliferation of MCF7 and T47D cell lines at physiological levels over short (48 h) incubations. Both 5 alpha-dihydrotestosterone and 5-androstene-3 beta,17 beta-diol stimulate proliferation of hormone-dependent cell lines at pharmacological levels via and interaction with the oestrogen receptor. In long (6-9 days) incubations both 5 alpha-dihydrotestosterone and 5-androstene-3 beta,17 beta-diol inhibit the 17 beta-oestradiol induced proliferation of MCF7 and T47D cell lines, however, 5 alpha-dihydrotestosterone inhibits while 5-androstene-3 beta,17 beta-diol stimulates basal proliferation. These cell line studies suggest a model for the role of precursor steroids in pre- and postmenopausal breast cancer.

Steroid sulphatase inhibitors for breast cancer therapy

In contrast to aromatase inhibitors, which are now in clinical use, the development of steroid sulphatase (STS) inhibitors for breast cancer therapy is still at an early stage. STS regulates the formation of oestrone from oestrone sulphate (E1S) but also controls the hydrolysis of dehydroepiandrosterone sulphate (DHEA-S). DHEA can be reduced to 5-androstenediol (Adiol), a steroid with potent oestrogenic properties. The active pharmacophore for potent STS inhibitors has now been identified, i.e. a sulphamate ester group linked to an aryl ring. This has led to the development of a number of STS inhibitors, some of which are due to enter Phase I trials in the near future. Such first generation inhibitors include the tricyclic coumarin-based 667 COUMATE. Aryl sulphamates, such as 667 COUMATE, are taken up by red blood cells (rbc), binding to carbonic anhydrase II (CA II), and transit the liver without undergoing first-pass inactivation. 667 COUMATE is also a potent inhibitor of CA II activity with an IC50 of 17 nM. Second generation STS inhibitors, such as 2-methoxyoestradiol bis-sulphamate (2-MeOE2bisMATE), in addition to inhibiting STS activity, also inhibit the growth of oestrogen receptor negative (ER-) tumours in mice and are anti-angiogenic. As the active pharmacaphores for the inhibition of aromatase and STS are now known it may be possible to develop third generation inhibitors that are capable of inhibiting the activities of both enzymes. Whilst exploring the potential of such a strategy it was discovered that 667 COUMATE possessed weak aromatase inhibitory properties with an IC50 of 300 nM in JEG-3 cells. The identification of potent STS inhibitors will allow the therapeutic potential of this new class of drug to be explored in post-menopausal women with hormone-dependent breast cancer. Second generation inhibitors, such as 2-MeOE2bisMATE, which also inhibit the growth of ER- tumours should be active against a wide range of cancers.

Dehydroepiandrosterone, a sex steroid metabolite in development for systemic lupus erythematosus

Deficiency of the weak androgen dehydroepiandrosterone (DHEA) and its sulfoconjugated metabolite DHEA-S has been associated with a number of serious illnesses, including lupus, diabetes, Alzheimer's disease and some cancers. Accordingly, supplementation with DHEA has been proposed for a variety of illnesses. Observational clinical studies and in vitro experiments have suggested that DHEA treatment might have a significant impact on immunological function, bone density, cognition, atherosclerotic disease, some malignancies, insulin resistance and obesity. Endogenous circulating DHEA levels, however, may vary widely by gender, age and ethnicity and can be affected by acute changes in corticosteroid production, alcohol intake, smoking, body mass index, medications and thyroid function [1-3]. Clearly, these variables complicate the interpretation of clinical data. DHEA also gives rise to a number of as yet poorly characterised metabolites, further confusing the assessment of its net effects when considered as treatment in heterogenous populations. Given the complexity of potential effects of DHEA and its metabolites, coupled to the diversity of clinical conditions that they might, at least in theory, affect, it is not surprising that clinical confirmation of efficacy in several clinical contexts has been inconsistent and controversial, hampering drug development in what might potentially be an important and widespread market. The current review will consider recent work suggesting efficacy of DHEA (GL-701, prasterone, Prestara( trade mark ) [US], Anastar( trade mark ) [Europe]; Genelabs) in systemic lupus erythematosus.

The effect of high dehydroepiandrosterone sulfate levels on tamoxifen blockade and breast cancer progression

BACKGROUND

We investigated the stimulatory potential of dehydroepiandrosterone sulfate (DHEA-S) on tamoxifen-treated cells and assessed its effect on cancer progression in the adjuvant setting.

METHODS

Mean serial serum levels of sex hormones from 44 patients receiving tamoxifen were correlated with follow-up status. T-47D (ER+/PR+) and HCC1937 (ER-/PR-) breast cancer cells were pretreated with 100 microM anastrozole, with or without tamoxifen, and stimulated with 22.8 microM DHEA-S. Rapid colorimetric assays allowed calculation of growth percent change.

RESULTS

Clinically, development of metastatic disease correlated only with > or =90 microg/dL DHEA-S (P = 0.005). In vitro, T-47D cells stimulated with DHEA-S after anastrozole showed 35% increased growth. Addition of 0.01 nM tamoxifen demonstrated -7% inhibition. Increasing the DHEA-S/tamoxifen ratio reversed suppression to +25%.

CONCLUSIONS

DHEA-S > or =90 microg/dL is a risk factor for recurrence in the adjuvant setting. In vitro, although tamoxifen inhibits cell growth at high doses it can be circumvented by DHEA-S. These results indicate that DHEA-S contributes to tamoxifen resistance and disease progression.

Pharmacology And Therapeutic Effects of Dehydroepiandrosterone In Older Subjects

Man and higher primates have adrenals that secrete large amounts of dehydroepiandrosterone (DHEA) [prasterone] and its sulphate (DHEAS) [PB 008]. A remarkable feature of plasma DHEAS levels in humans is their great decrease with aging. Researchers have postulated that this age-related decline of DHEAS levels may explain some of the degenerative changes associated with aging. Moreover, administration of DHEA to laboratory animals has demonstrable beneficial effects such as prevention of diabetes mellitus, obesity, cancer, heart disease and positive immunomodulator effects. However, in rodents DHEA(S) circulating levels are so low that it is impossible to detect any significant age-related decrease. Therefore results from rodent experiments are not relevant to human beings. Three mechanisms of action of DHEA(S) have been identified. DHEA and DHEAS are precursors of testosterone and estradiol, DHEAS is a neurosteroid which modulates neuronal excitability via specific interactions with neurotransmitter receptors and DHEA is an activator of calcium-gated potassium channels. Randomised, placebo-controlled clinical trials which included healthy individuals aged 60 years and over treated with (near) physiological doses of DHEA (50-100 mg/day) have yielded very few positive results. Impact of DHEA replacement treatment was assessed on mood, well being, cognitive and sexual functions, bone mass, body composition, vascular risk factors, immune functions and skin. The major limitations of these trials were their short duration (maximum 1 year) and the low number of study participants involved (maximum 280). Many elderly people in western countries take DHEA without medical supervision. In the US, DHEA is even classified as food supplement. At present there is no scientific evidence to recommend DHEA replacement in the elderly. Further studies are needed to form conclusions about the efficacy and the safety of DHEA replacement in elderly, and to better understand the mechanisms of action of DHEA at the molecular and cellular levels.

[DHEA: desire and resistance]

DHEA is a prohormone that is secreted by the corticoadrenal glands on a nyctohemeral rhythm alike to that of testosterone. Its plasmatic level gets reduced with ageing in a great amount of individuals, but not in all. Moreover, DHEA is a neurosteroid synthesized by certain neurons. As shown by correlation studies, lowered levels of DHEA wre linked to a higher death rate, in part of the studied population. Besides, an improvement in well being as well as in some mental functions, after a 50 mg daily intake, was shown in preliminary studies. Many well-conducted studies followed which only partially confirmed the previous ones. Nowadays, it seems to be taken for granted that DHEA becomes estrogens and androgens and that its action on women is mainly an androgenic one. DHEA becomes active after intracellular transformation, which varies according to the enzymatic set of cells. Some effect on elderly women's libido, and improvement in erectile dysfunction in men without vascular pathology but a lowered DHEA level, has been observed. Thus, using DHEA in order to cure sexual troubles might be considered, although the possible negative effects of DHEA, especially on breast and prostate, have not been discarded yet. The conditions under which it could have a beneficial effect on mental functions remains to be discovered. Acknowledgement of those pathological situations, in which DHEA could prove useful, as well as the administration posology is, therefore, crucial.