Multiple actions of synthetic 'progestins' on the growth of ZR-75-1 human breast cancer cells: an in vitro model for the simultaneous assay of androgen, progestin, estrogen, and glucocorticoid agonistic and antagonistic activities of steroids

Mechanisms behind context-dependent role of glucocorticoids in breast cancer progression

Glucocorticoids (GCs), mostly dexamethasone (dex), are routinely administered as adjuvant therapy to manage side effects in breast cancer. However, recently, it has been revealed that dex triggers different effects and correlates with opposite outcomes depending on the breast cancer molecular subtype. This has raised new concerns regarding the generalized use of GC and suggested that the context-dependent effects of GCs can be taken into potential consideration during treatment design. Based on this, attention has recently been drawn to the role of the glucocorticoid receptor (GR) in development and progression of breast cancer. Therefore, in this comprehensive review, we aimed to summarize the different mechanisms behind different context-dependent GC actions in breast cancer by applying a multilevel examination, starting from the association of variants of the GR-encoding gene to expression at the mRNA and protein level of the receptor, and its interactions with other factors influencing GC action in breast cancer. The role of GCs in chemosensitivity and chemoresistance observed during breast cancer therapy is discussed. In addition, experiences using GC targeting therapeutic options (already used and investigated in preclinical and clinical trials), such as classic GC dexamethasone, selective glucocorticoid receptor agonists and modulators, the GC antagonist mifepristone, and GR coregulators, are also summarized. Evidence presented can aid a better understanding of the biology of context-dependent GC action that can lead to further advances in the personalized therapy of breast cancer by the evaluation of GR along with the conventional estrogen receptor (ER) and progesterone receptor (PR) in the routine diagnostic procedure.

Anti-proliferative transcriptional effects of medroxyprogesterone acetate in estrogen receptor positive breast cancer cells are predominantly mediated by the progesterone receptor

Medroxyprogesterone acetate (MPA) is a first generation progestin that has been in clinical use for various hormonal conditions in women since the 1960s. Although developed as a progesterone receptor (PR) agonist, MPA also has strong binding affinity for other steroid receptors. This promiscuity confounds the mechanistic action of MPA in target cells that express multiple steroid receptors. This study is the first to assess the relative contribution of progesterone, androgen and glucocorticoid receptors in mediating the transcriptional activity of MPA on endogenous targets in breast cancer cells that endogenously express all three receptors at comparable levels. Gene expression profiling in estrogen receptor positive (ER+) ZR-75-1 breast cancer cells demonstrated that although the MPA-regulated transcriptome strongly overlapped with that of Progesterone (PROG), 5α-dihydrotestosterone (DHT) and Dexamethasone (DEX), it clustered most strongly with that of PROG, suggesting that MPA predominantly acts via the progesterone receptor (PR) rather than androgen receptor (AR) or glucocorticoid receptor (GR). Subsequent experiments manipulating levels of these receptors, either through specific culture conditions or with lentiviral shRNAs targeting individual receptors, also revealed a stronger contribution of PR compared to AR and GR on the expression of endogenous target genes that are either commonly regulated by all ligands or specifically regulated only by MPA. A predominant contribution of PR to MPA action in ER+ T-47D breast cancer cells was also observed, although a stronger role for AR was evident in T-47D compared to that observed in ZR-75-1 cells. Network analysis of ligand-specific and commonly regulated genes demonstrated that MPA utilises different transcription factors and signalling pathways to inhibit proliferation compared with PROG. This study reaffirms the importance of PR in mediating MPA action in an endogenous breast cancer context where multiple steroid receptors are co-expressed and has potential implications for PR-targeting therapeutic strategies in ER+ breast cancer.

KISS1 in breast cancer progression and autophagy

Tumor suppressors are cellular proteins typically expressed in normal (non-cancer) cells that not only regulate such cellular functions as proliferation, migration and adhesion, but can also be secreted into extracellular space and serve as biomarkers for pathological conditions or tumor progression. KISS1, a precursor for several shorter peptides, known as metastin (Kisspeptin-54), Kisspeptin-14, Kisspeptin-13 and Kisspeptin-10, is one of those metastasis suppressor proteins, whose expression is commonly downregulated in the metastatic tumors of various origins. The commonly accepted role of KISS1 in metastatic tumor progression mechanism is the ability of this protein to suppress colonization of disseminated cancer cells in distant organs critical for the formation of the secondary tumor foci. Besides, recent evidence suggests involvement of KISS1 in the mechanisms of tumor angiogenesis, autophagy and apoptosis regulation, suggesting a possible role in both restricting and promoting cancer cell invasion. Here, we discuss the role of KISS1 in regulating metastases, the link between KISS1 expression and the autophagy-related biology of cancer cells and the perspectives of using KISS1 as a potential diagnostic marker for cancer progression as well as a new anti-cancer therapeutics.

Endocrine Disruptors: A Critical Review of In Vitro and In Vivo Testing Strategies for Assessing Their Toxic Hazard to Humans

Currently, there is much concern that a wide range of both synthetic and naturally occurring environmental chemicals can act as endocrine disruptors (EDs), and can adversely affect humans and wildlife. Many in vivo and in vitro tests have been proposed for screening EDs, and several regulatory agencies, including the US Environmental Protection Agency (EPA), have recommended tier-testing schemes. Unfortunately, most of the proposed toxicity tests have substantial problems, including non-specificity and lack of reproducibility. There is also uncertainty concerning their relevance for generating useful hazard data for risk assessment purposes, in view of the diversity of the possible ED mechanisms of action (for example, receptor binding, steroidogenesis and modulation of the homeostatic processes which regulate endogenous responses to hormones). Moreover, most of the suggested test methods have yet to be validated according to internationally accepted criteria, although the OECD and the US EPA have defined tests for validation, and an interlaboratory “prevalidation” exercise has been initiated by the OECD. All this is compounded by the lack of information regarding human exposure levels to EDs, and a lack of direct evidence for a causal link between exposure and the development of adverse human health effects. In addition, the regulatory testing of EDs has important negative implications for animal welfare, as some of the proposed in vivo tests require large group sizes of animals and stressful procedures. From a detailed analysis of the available published literature, it is concluded that it is impossible to assess the relative values of currently available in vitro and in vivo toxicity tests for EDs, or to recommend any test or test battery. Any plans for the widespread testing of EDs are therefore premature and might be unnecessary, at least for detecting possible human effects. Several recommendations are made for rectifying this unsatisfactory situation, including the postponement of screening programmes pending: a) more information on human exposure; b) further details of the mechanisms of action of EDs; and c) the development of improved tests, followed by their proper scientific validation.

Reproductive and transcriptional effects of the antiandrogenic progestin chlormadinone acetate in zebrafish (Danio rerio)

Chlormadinone acetate (CMA) is a frequently used progestin with antiandrogenic activity in humans. Residues may enter the aquatic environment but potential adverse effects in fish are unknown. While our previous work focused on effects of CMA in vitro and in zebrafish eleuthero-embryos, the present study reports on reproductive and transcriptional effects in adult female and male zebrafish (Danio rerio). We performed a reproductive study using breeding groups of zebrafish. After 15 days of pre-exposure, we exposed zebrafish to different measured concentrations between 6.4 and 53,745 ng/L CMA for 21 days and counted produced eggs daily to determine fecundity. Additionally, transcriptional effects of CMA in brains, livers, and gonads were analyzed. CMA induced a slight but statistically significant reduction in fecundity at 65 ng/L and 53,745 ng/L compared to pre-exposure. Furthermore, we observed differential expression for gene transcripts of steroid hormone receptors, genes related to the hypothalamic-pituitary-gonadal axis, and steroidogenesis. In particular, we found a significant decrease of transcript levels of vitellogenin (vtg1) in ovaries and liver, and of cyp2k7 in the liver of males, as well as a significant increase of transcripts of the progesterone receptor (pgr) in testes, and cyp2k1 in the liver of females. The observed effects were weaker than those of other very potent progestins, which is probably related to the lack of interaction of CMA with the zebrafish progesterone receptor.

Progesterone induces progesterone receptor gene (PGR) expression via rapid activation of protein kinase pathways required for cooperative estrogen receptor alpha (ER) and progesterone receptor (PR) genomic action at ER/PR target genes

Progesterone Receptors (PRs) are critical effectors of estrogen receptor (ER) signaling required for mammary gland development and reproductive proficiency. In breast and reproductive tract malignancies, PR expression is a clinical prognostic marker of ER action. While estrogens primarily regulate PR expression, other factors likely contribute to a dynamic range of receptor expression across diverse tissues. In this study, we identified estrogen-independent but progestin (R5020)-dependent regulation of ER target genes including PGR in ER+/PR+ cancer cell lines. R5020 (10nM-10μM range) induced dose-dependent PR mRNA and protein expression in the absence of estrogen but required both PR and ERα. Antagonists of either PR (RU486, onapristone) or ERα (ICI 182,780) attenuated R5020 induction of TFF1, CTSD, and PGR. Chromatin immunoprecipitation (ChIP) assays performed on ER+/PR+ cells demonstrated that both ERα and PR were recruited to the same ERE/Sp1 site-containing region of the PGR proximal promoter in response to high dose progestin (10μM). Recruitment of ERα and PR to chromatin and subsequent PR mRNA induction were dependent upon rapid activation of MAPK/ERK and AKT; inhibition of these kinase pathways via U0126 or LY294002 blocked these events. Overall, we have identified a novel mechanism of ERα activation initiated by rapid PR-dependent kinase pathway activation and associated with phosphorylation of ERα Ser118 for estrogen-independent but progestin-dependent ER/PR cross talk. These studies may provide insight into mechanisms of persistent ER-target gene expression during periods of hormone (i.e. estrogen) ablation and suggest caution following prolonged treatment with aromatase or CYP17 inhibitors (i.e. contexts when progesterone levels may be abnormally elevated).

Ethinyl estradiol and levonorgestrel alter cognition and anxiety in rats concurrent with a decrease in tyrosine hydroxylase expression in the locus coeruleus and brain-derived neurotrophic factor expression in the hippocampus

In the United States, more than ten million women use contraceptive hormones. Ethinyl estradiol and levonorgestrel have been mainstay contraceptive hormones for the last four decades. Surprisingly, there is scant information regarding their action on the central nervous system and behavior. Intact female rats received three weeks of subcutaneous ethinyl estradiol (10 or 30μg/rat/day), levonorgestrel (20 or 60μg/rat/day), a combination of both (10/20μg/rat/day and 30/60μg/rat/day), or vehicle. Subsequently, the rats were tested in three versions of the novel object recognition test to assess learning and memory, and a battery of tests for anxiety-like behavior. Serum estradiol and ovarian weights were measured. All treatment groups exhibited low endogenous 17β-estradiol levels at the time of testing. Dose-dependent effects of drug treatment manifested in both cognitive and anxiety tests. All low dose drugs decreased anxiety-like behavior and impaired performance on novel object recognition. In contrast, the high dose ethinyl estradiol increased anxiety-like behavior and improved performance in cognitive testing. In the cell molecular analyses, low doses of all drugs induced a decrease in tyrosine hydroxylase mRNA and protein in the locus coeruleus. At the same time, low doses of ethinyl estradiol and ethinyl estradiol/levonorgestrel increased galanin protein in this structure. Consistent with the findings above, the low dose treatments of ethinyl estradiol and combination ethinyl estradiol/levonorgestrel reduced brain-derived neurotrophic factor mRNA in the hippocampus. These effects of ethinyl estradiol 10μg alone and in combination with levonorgestrel 20μg suggest a diminution of norepinephrine input into the hippocampus resulting in a decline in learning and memory.

The role of 5α-reductase type 1 associated with intratumoral dihydrotestosterone concentrations in human endometrial carcinoma

Endometrial carcinoma, especially endometrioid endometrial adenocarcinoma, is an estrogen-dependent tumor that is similar to breast cancer. Androgen is closely associated with other steroid hormones, but its correlation with endometrioid endometrial adenocarcinoma remains largely unclear. We previously demonstrated the expression of the androgen receptor, 5α-reductase type 1, and 5α-reductase type 2 in endometrioid endometrial adenocarcinoma tissue, but androgen action and its correlation with prognosis are unknown. In this study, we measured the tissue and serum concentrations of androgen and performed immunohistochemical analyses of androgen-associated factors in 41 patients. In 86 additional patients, we performed the same immunohistochemical analyses to identify correlations associated with prognosis. We found that 5α-reductase type 1 was associated with intratumoral dihydrotestosterone concentrations, and it was an independent prognostic factor in endometrioid endometrial adenocarcinoma. The poor prognosis of patients negative for both androgen receptor and 5α-reductase type 1 suggests that androgens have inhibitory effects on tumor growth.

A novel framework for interpretation of data from the fish short-term reproduction assay (FSTRA) for the detection of endocrine-disrupting chemicals

The fish short-term reproduction assay (FSTRA) is a key component of the US Environmental Protection Agency's Endocrine Disruptor Screening Program (EDSP), which uses a weight-of-evidence analysis based on data from several assays to identify the potential for chemicals to act as agonists or antagonists of the estrogen or androgen receptors (ER and AR), or inhibitors of steroidogenic enzymes. The FSTRA considers a variety of mechanistic and apical responses in 21-d exposures with the fathead minnow (Pimephales promelas), including plasma steroid and vitellogenin (VTG; egg yolk protein) concentrations, secondary sex characteristics, gonad size and histopathology, and egg production. Although the FSTRA initially was described several years ago, recent data generation associated with implementation of the EDSP highlighted the need for more formal guidance regarding evaluation of information from the assay. The authors describe a framework for interpretation of FSTRA data relative to perturbation of endocrine pathways of concern to the EDSP. The framework considers end points individually and as suites of physiologically related responses relative to pathway identification. Sometimes changes in single end points can be highly diagnostic (e.g., induction of VTG in males by ER agonists, production of male secondary sex characteristics in females by AR agonists); in other instances, however, multiple, related end points are needed to reliably assess pathway perturbation (e.g., AR antagonism, steroid synthesis inhibition). In addition to describing an interpretive framework, the authors demonstrate its practical utility using publicly available FSTRA data for a wide range of known and hypothesized endocrine-disrupting chemicals. Environ Toxicol Chem 2014;33:2529-2540. Published 2014 Wiley Periodicals Inc., on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

Multiple nuclear receptor signaling pathways mediate the actions of synthetic progestins in target cells

Synthetic progestins are used clinically to treat a variety of women's health issues. Although progestins are designed to signal through the progesterone receptor (PR) to elicit specific pharmacological effects, they can also variably bind to and influence the activity of other nuclear receptors within target tissues, particularly the androgen and glucocorticoid receptors and, in some cases, they regulate mineralocorticoid and estrogen receptors. This article reviews current knowledge on progestin cross-talk to nuclear receptors other than PR, their resultant effect on receptor function in different in vitro models and the potential consequences of this activity for breast, ovarian and endometrial cancer. The impact of cell and tissue context, assay type, steroid metabolism and hormonal milieu in determining progestin-mediated activity are also presented. Collectively this review highlights the complexity of progestin action and the need for consideration of multiple mechanisms that act in concert to influence their ultimate biological activity.

Progesterone and levonorgestrel regulate expression of 17βHSD-enzymes in progesterone receptor positive breast cancer cell line T47D

The use of combined hormone replacement therapy (HRT) with oestrogens and progestins in postmenopausal women has been associated with an increased risk for developing breast cancer. The reasons are not fully understood, but influence of HRT on endogenous conversion of female sex hormones may be involved. The expression of 17β hydroxysteroid dehydrogenases (17βHSD), which are enzymes catalysing the conversion between more or less potent oestrogens, may partly be regulated by progestins. The breast cancer cell lines T47D, MCF7 and ZR75-1 were treated with progesterone, medroxyprogesterone acetate (MPA) or levonorgestrel for 48 and 72 h at 10(-7) and 10(-9)M to investigate influence on 17βHSD1, 17βHSD2 and 17βHSD5 mRNA expression measured by real time PCR. The expression of 17βHSD1 increased in progesterone and levonorgestrel treated T47D cells (48 h 10(-7)M P=0.002; P<0.001) and 17βHSD5 increased after progesterone treatment (48 h 10(-7)M P=0.003), whereas the expression of 17βHSD2 decreased after the (48 h 10(-7)M P=0.003; P<0.001). Similar, but less prominent effects were seen in MCF7 and ZR75-1. The progestin effects on 17βHSD-expression were lost when T47D cells were co-treated with progestins and the progesterone receptor (PgR) inhibitor mifprestone. We show that both reductive (17βHSD1 and 17βHSD5) and oxidative (17βHSD2) members of the 17βHSD-family are under control of progesterone and progestins in breast cancer cell lines. This is most clear in T47D cells which have high PgR expression. 17βHSD-enzymes are important players in the regulation of sex steroids locally in breast tumours and tumoural expression of various 17βHSD-enzymes have prognostic and treatment predictive relevance. We propose a mechanism for increased breast cancer risk after HRT in which hormone replacement affects the expression of 17βHSD-enzymes, favouring the expression of reductive enzymes, which in turn could increase levels of bioactive and mitogenic estrogens in local tissue, e.g. breast tissue.

Glucocorticoid receptor and breast cancer

Stress enhances glucocorticoid (GC) synthesis, which alters inflammation and immune responses, as well as cellular proliferation and apoptosis in a number of tissues. Increasingly, stress has been associated with cancer progression, and in particular in breast cancer. Consequently, an operational glucocorticoid receptor system in breast tissue influences breast cancer development. In this review, we summarize the data on the GC/GR system in normal and tumoral breast tissue. We also review the molecular mechanisms by which GCs control apoptosis and proliferation in breast cancer models and how GCs alter the chemotherapy of breast cancer treatment when used in combination. Finally, we discuss the participation of GR in breast tumorigenesis under hormone replacement therapy.

Reproductive responses in fathead minnow and Japanese medaka following exposure to a synthetic progestin, Norethindrone

Synthetic progestins, such as Norethindrone (NET), are common ingredients in oral contraceptives and in treatment for post-menopausal problems. Given the widespread use of oral contraceptives and post-menopausal treatments, several reports have targeted and identified progestins in aquatic environments. In fish, progestins play an important role in the stimulation of oocyte final maturation and ovulation in females, stimulation of spermiation and sperm motility in males, and the initiation of meiosis in both sexes. They also have a role as pheromones in some species. Given the pivotal role that progestins play in reproduction, their appreciable daily dose (i.e. microg to mg range in contraceptives and hormone replacement therapies) and continuous use pattern, it is important to understand the potential risk these compounds pose once discharged into the aquatic environment. Since little published data are available on this class of compounds, our research focused on the reproductive effects of NET on the fathead minnow and Japanese medaka. A 28 day static-renewal reproduction study with Japanese medaka indicated that NET produces a significant decrease in fecundity at aqueous concentrations >or=25 ng/L. A 21 day flow-though fathead minnow reproduction study also demonstrated that NET causes a significant decrease in fecundity in the low ng/L range. Fathead minnow morphological changes (i.e. female fin spots) suggest that NET exposure may have a potent androgenic effect on fish; however, plasma 11-Ketotestosterone (11-KT) concentrations were reduced in males at the highest exposure concentration. Collectively, these data indicate that further investigation of reproductive responses associated with synthetic progestins is warranted.

Differential effects of medroxyprogesterone acetate on thrombosis and atherosclerosis in mice

BACKGROUND AND PURPOSE

The risk for cardiovascular events including venous and arterial disease and stroke is elevated after treatment with estrogen and medroxyprogesterone acetate (MPA) in postmenopausal women. Here, we have investigated the effect of MPA on arterial thrombosis and atherosclerosis in a murine model of atherosclerosis.

EXPERIMENTAL APPROACH

Apolipoprotein E (ApoE)-/- mice were bilaterally ovariectomized and treated with placebo, MPA (27.7 microg day(-1)) and MPA + 17-beta-oestradiol (E2; 1.1 microg day(-1)) for 90 days, on a Western-type diet. Thrombotic response was measured in a photothrombosis model, platelet activation by fluorescence activated cell sorting (FACS) analysis (CD62P) and thrombin generation by the endogenous thrombin potential (ETP). Furthermore, aortic plaque burden and aortic root plaque composition were determined.

KEY RESULTS

MPA and MPA + E2-treated animals showed an aggravated thrombotic response shown by significantly reduced time to stable occlusion. The pro-thrombotic effect of MPA was paralleled by increased ETP whereas platelet activation was not affected. Furthermore, MPA + E2 reduced the number of cells positive for alpha-smooth muscle actin and increased hyaluronan in the plaque matrix. Interestingly, total plaque burden was reduced by MPA but unchanged by MPA + E2.

CONCLUSION AND IMPLICATIONS

Long-term treatment with MPA and MPA + E2 increased arterial thrombosis despite inhibitory effects of MPA on atherosclerosis in ApoE-deficient mice. Increased thrombin formation, reduced smooth muscle content and remodelling of non-collagenous plaque matrix may be involved in the pro-thrombotic effects. Thus, MPA exhibits differential effects on arterial thrombosis and on atherosclerosis.

Antigonadotropic progestogens as contraceptive agents in women with contraindication to combined pill

Synthetic progestogens belong to different pharmacological classes and are mixed steroids. They display different properties due to their various affinities to the different steroid receptors. In addition, the dosage used can modify their side effects. Normethyltestosterone used at minimal doses, also called progestogen only pill (POP), constitute the standard recommended hormonal contraception for women with vascular and metabolic contraindications to combined pill (COC). However, POP efficacy and gynecological tolerance are limited. We have developed for more than 20 years in France the use of two pregnane derivatives as contraceptive agents in women with contraindication to COC. Chlormadinone acetate and cyproterone acetate have different antigonadotropic potencies but remain neutral on vascular risk. We have analyzed the efficacy, vascular and gynecological tolerances in 187 women with systemic lupus erythematous with or without antiphospholipids. Venous thrombosis and arterial events rates were lower than those reported in the literature. The current experience in women with thrombophilia is similar as reported in a series of 150 patients. In addition, we have also used antigonadotropic progestins in women with hereditary angioedema (HAE) types I, II or III. HAE symptoms can be induced or worsened by COC. We could demonstrate a significant improvement of the symptoms in most women with HAE under antigonadotropic progestins. Gynecological and general tolerances were satisfactory. In conclusion, antigonadotropic progestins could have clinical positive benefits as contraceptive agents in women with contraindication to COC.

Usage of megestrol acetate in the treatment of anorexia-cachexia syndrome in the elderly

The aim of this review is to assess the efficacy and safety of megestrol acetate (MA) in geriatric cachexia. The paper presented here reviews a previously published study of MA use in 69 patients in a randomized double blind placebo-controlled trial. This paper will also address the underlying pathogenesis of cachexia (specifically, the role of cytokines) along with the use of MA, its mechanism of action and its side effects.

OBJECTIVE

To compare the effects of MA oral suspension (O.S.), 800 mg/day, versus placebo on weight in geriatric nursing home patients with weight loss or low body weight.

DESIGN

Twelve weeks, randomized, double-blind, placebo-controlled trial with a 13-week follow-up period.

PATIENTS

Northport VAMC Nursing home patients with weight loss of * 5% of usual body weight over the past 3 months, or body weight 20% below their ideal body weight.

INTERVENTIONS

Patients were randomly assigned to receive placebo or MA 800 mg/d for 12 weeks and were then followed for 13 weeks off treatment and mortality 4 years post treatment.

MEASUREMENTS

Primary outcome- weight and appetite change. Secondary outcome-sense of well being, enjoyment of life, change in depression scale, laboratory nutrition parameters, energy intake counts, body composition, and adverse events.

RESULTS

At 12 weeks there were no significant differences in weight gain between treatment groups, while MA-treated patients reported significantly greater improvement in appetite, enjoyment of life, and well being. At week 25 (3 months after treatment), 61.9% of MA-treated patients had gained * 1.82 kg (4 lbs) compared to 21.7% of placebo patients. There was no difference in survival between MA and placebo groups. Considering possible confounders, higher initial IL-6, initial TNFR-p75 levels, and final neutrophil percentage were associated with elevated mortality, whereas higher initial pre-albumin, initial albumin, final pre-albumin, final albumin and final weight gain were associated with decreased death.

Pharmacological Treatment of Geriatric Cachexia: Evidence and Safety in Perspective

Anticachexic or antisarcopenic medications are prescribed worldwide for geriatric patients with poor appetite and associated weight loss. They represent a valuable treatment option for managing cachexia. However, the well-publicized adverse reports about these medications in acquired immunodeficiency syndrome (AIDS) and in the cancer population has led to some concern and much subsequent discussion over the safety of these medications being used in geriatric population. This review looks at the evidence in relation to the benefits and risks of these medications and discusses what we know about their use in the geriatric population.

Antiandrogenic activity of norgestimate in a human androgen-dependent stable-transfected cell line

BACKGROUND

Acne occurs from an overstimulation of the sebaceous glands by high levels of androgens or because sebaceous glands are hypersensitive to normal levels of testosterone. In women with moderate acne, norgestimate (NG) in association with ethinyl estradiol (EE) is acknowledged as an effective treatment; this is related to the effect of oral contraceptives on androgen production and transport. However, the antiandrogenic properties of NG itself have been poorly studied.

DESIGN

The present work was undertaken to find out whether NG and its derivative, 17-deacetylnorgestimate (dNG), present antiandrogen activity. First, we studied the effect of NG and dNG on the intracellular localization of green fluorescent protein (GFP)-labeled androgen receptor (AR). Then, we compared the AR activity of NG and dNG with that of cyproterone acetate (CPA), a gold-standard antiandrogenic compound, by investigating competitive binding, antagonist activity and transactivation level of AR.

RESULTS

NG and dNG decreased GFP-AR nuclear translocation, revealing their antiandrogenic property, as for CPA. In the whole cell competition assay performed in a human cell line stably expressing an AR-responsive luminescent reporter gene (PALM cells) with (3)H-labeled R1881 as tracer, NG and dNG were slightly stronger competitors than the antiandrogen CPA. Half-maximal inhibition (K(i)) of (3)H-labeled R1881 (10(-9) M) binding occurred at 4.2 +/- 0.5 x 10(-8) M of NG, 3.4 +/- 0.4 x 10(-8) M of dNG and 6.6 +/- 0.8 x 10(-8) M of CPA. Comparison of antagonist activities of NG, dNG and CPA on AR transactivation levels showed that NG, dNG and CPA inhibited androgen-induced luciferase activity in PALM cells. We observed slight and similar inhibition with 6 x 10(-8) M respectively of NG, dNG and CPA. For the three compounds, the best inhibitory effect was found at 3 x 10(-7) M: 24% for NG and dNG vs. 47% for CPA. The antiandrogenic activity of NG and dNG was found to be 50% that of CPA.

CONCLUSION

In a human androgen-dependent stable-transfected cell line, a useful tool for studying AR transcriptional activity and its subnuclear localization in the presence of androgens and antiandrogens, we demonstrated that NG and dNG have antiandrogenic properties that could partly explain the efficacy of NG in association with EE for the treatment of moderate acne in women.

Effects-directed analysis of organic toxicants in wastewater effluent from Zagreb, Croatia

The organic toxicants present in the effluent of the main sewer of the city of Zagreb, Croatia were isolated and identified through the use of effects-directed characterisation techniques. At the time of investigation, the wastewater effluent received no treatment and was comprised of a mixture of effluent from domestic and industrial sources. The organic load of the wastewater was isolated by solid phase extraction and toxicity profiles obtained using reverse-phase HPLC. All procedures were evaluated through the analysis of a series of reference compounds of widely differing polarity. Toxicity profiles for EROD activity (CYP1A induction), vitellogenin induction (estrogenic activity), cytotoxicity (membrane stability and metabolic inhibition) were obtained using a rainbow trout (Oncorhynchus mykiss) primary hepatocyte bioassay. The suite of bioassays showed biological responses after exposure to the raw extracts for all the endpoints tested. However, a combination of mixture toxicity and cytotoxicity in the complex raw extract had some masking effect on the sub-lethal responses of vitellogenin and EROD induction. Bioassay testing of the fine fractions obtained by HPLC produced a range of endpoint-specific toxicity profiles for each sample. A number of compounds were identified by the use of GC-MS and LC-MS/MS as responsible for the observed effects. The steroid estrogens 17 beta-estradiol and estriol were identified by LC-MS/MS as estrogen receptor agonists in two of the estrogenic fractions. In addition, GC-MS analysis identified different alkylphenols, benzophenone and methylparaben which also contributed to the estrogenic activity of the sample. Polycyclic aromatic hydrocarbons (PAHs), alkyl substituted PAHs, nitro-polycyclic aromatic compounds (nitro-PACs), carbazoles and alkyl substituted carbazoles and other known CYP1A inducers were identified by GC-MS analysis as responsible for some of the observed EROD activity. Some active compounds remain unidentified.

Differential effects of progestogens, by type and regimen, on estrogen-metabolizing enzymes in human breast cancer cells

OBJECTIVES

To investigate the in vitro effects of five progestogens commonly used in hormone replacement therapy (HRT) on estrogen-metabolizing enzymes in human breast cancer cells.

METHODS

The human hormone-dependent breast cancer cell lines T47D, MCF-7, and MCF-7aro were cultured with estradiol (E(2)) and progestogens. The mRNA levels of estrogen-metabolizing enzymes were determined by RT-PCR or Northern blot, and enzyme activities by radiolabeled substrates. Cell proliferation was measured by bromodeoxyuridine incorporation. In vitro models for continuous combined regimen (CCR) and sequential combined regimen (SCR) were established to mimic the in vivo conditions of HRT.

RESULTS

Medroxyprogesterone acetate (MPA) plus E(2) (10(-8)M) stimulated the mRNA levels and activities of estrogen-activating enzymes aromatase (at 10(-8)M MPA), 17beta-hydroxysteroid dehydrogenase type 1 (17betaHSD1) (at 10(-6)M), and sulfatase (at 10(-8) to 10(-6)M) compared to E(2) only. Progesterone also stimulated enzyme activity, but to a lower magnitude. Levonorgestrel, norethindrone, and dienogest showed no enzyme stimulation. The estrogen-inactivating enzymes 17beta-hydroxysteroid dehydrogenase type 2 and sulfotransferase were not affected by any of the progestogens tested. However, all the progestogens (at 10(-8) to 10(-6)M) inhibited E(2)-stimulated cell proliferation. While increased aromatase and 17betaHSD1 activities were observed in the CCR model, no significant enzyme stimulation was observed in the SCR model.

CONCLUSIONS

The present study suggested that progestogens exert different actions on estrogen-metabolizing enzymes in breast cancer cells dependent on the specific progestogen and regimen used. Further studies are needed to elucidate whether MPA, a progestogen currently used in HRT, leads to a higher risk of breast cancer development than other progestogens.

The progestational and androgenic properties of medroxyprogesterone acetate: gene regulatory overlap with dihydrotestosterone in breast cancer cells

Introduction

Medroxyprogesterone acetate (MPA), the major progestin used for oral contraception and hormone replacement therapy, has been implicated in increased breast cancer risk. Is this risk due to its progestational or androgenic properties? To address this, we assessed the transcriptional effects of MPA as compared with those of progesterone and dihydrotestosterone (DHT) in human breast cancer cells.

Method

A new progesterone receptor-negative, androgen receptor-positive human breast cancer cell line, designated Y-AR, was engineered and characterized. Transcription assays using a synthetic promoter/reporter construct, as well as endogenous gene expression profiling comparing progesterone, MPA and DHT, were performed in cells either lacking or containing progesterone receptor and/or androgen receptor.

Results

In progesterone receptor-positive cells, MPA was found to be an effective progestin through both progesterone receptor isoforms in transient transcription assays. Interestingly, DHT signaled through progesterone receptor type B. Expression profiling of endogenous progesterone receptor-regulated genes comparing progesterone and MPA suggested that although MPA may be a somewhat more potent progestin than progesterone, it is qualitatively similar to progesterone. To address effects of MPA through androgen receptor, expression profiling was performed comparing progesterone, MPA and DHT using Y-AR cells. These studies showed extensive gene regulatory overlap between DHT and MPA through androgen receptor and none with progesterone. Interestingly, there was no difference between pharmacological MPA and physiological MPA, suggesting that high-dose therapeutic MPA may be superfluous.

Conclusion

Our comparison of the gene regulatory profiles of MPA and progesterone suggests that, for physiologic hormone replacement therapy, the actions of MPA do not mimic those of endogenous progesterone alone. Clinically, the complex pharmacology of MPA not only influences its side-effect profile; but it is also possible that the increased breast cancer risk and/or the therapeutic efficacy of MPA in cancer treatment is in part mediated by androgen receptor.

The effect of megestrol acetate on growth of HepG2 cells in vitro and in vivo

PURPOSE

Hepatocellular carcinoma (HCC) is generally considered as a sex hormone-dependent tumor, and hormonal therapy has been proposed as a strategy for the treatment of HCC. The aim of the study is to investigate the effect of megestrol acetate, a synthetic progesteronal agent, on growth of HepG2 cells in vitro and in vivo.

EXPERIMENTAL DESIGN

Cell growth in vitro was assessed by a colormetric method, and cell growth in vivo was assessed by tumor volumetrics.

RESULTS

Megestrol acetate was shown to inhibit the growth of HepG2 cells in vitro in dose- and time-dependent manners with an IC (50) of 260 microm (24-h incubation). The growth of HepG2 cell-transplanted tumors in nude mice was also inhibited by i.p. injection of megestrol acetate (10 mg/kg/day). The tumor volumes of the megestrol acetate-treated group regressed to 59% of controls by week 6 and to 41% of controls by week 13. Apoptosis following G(1) arrest was observed in megestrol acetate-treated cells and may be a mechanism through which megestrol acetate inhibits HepG2 cells. Megestrol acetate was also demonstrated to have a beneficial effect on the weight gain of tumor-bearing nude mice, and the mean weight of the megestrol acetate-treated animals was higher than that of controls from week 4 of the treatment period, and the differences were statistically significant in week 5 and 6 (P < 0.05, compared with controls). No significant survival advantage was, however, demonstrated in the treatment group.

CONCLUSIONS

This study showed that megestrol acetate inhibited the growth of HepG2 cells grown in vitro and in vivo. These data provide useful information for clinical study of megestrol acetate for the treatment of HCC.

Characterisation of steroid receptor expression in the human prostate carcinoma cell line 22RV1 and quantification of androgen effects on mRNA regulation of prostate-specific genes

In this study, the effect of natural androgens on the expression of androgen-regulated genes in the human prostate carcinoma cell line 22RV1 was characterised. To clarify the usefulness of the cells for in vitro studies concerning activation of androgen responsive genes by various steroidal compounds steroid receptor expression patterns had to be characterised intensively. Expression of androgen receptor (AR), estrogen receptor alpha (ERalpha) and beta (ERbeta), progestin receptor (PR) and glucocorticoid receptor alpha and beta was investigated by the means of RT-PCR, immunocytochemistry, ligand binding or Western blot. 22RV1 cells were proved to express androgen receptor and less glucocorticoid receptor beta on mRNA level. The confirmed mutation of the androgen receptor at codon H874 slightly apart from the steroid binding pocket seemed not to cause alteration of natural steroid hormone binding. mRNA expression of all progestin and estrogen receptor isoforms as well as glucocorticoid receptor alpha could not be detected. To study functional relevance of above-mentioned findings nine androgen-regulated genes were chosen to characterise the cell line and to determine androgenic effects using highly sensitive real-time RT-PCR. Addition of the three natural steroids dihydrotestosterone (DHT), testosterone, and 19-nortestosterone significantly influenced mRNA expression profiles. All compounds under study showed clear time-dependent and androgen-specific effects on transcriptional level. The results demonstrate that the cultivated human prostate carcinoma epithelial cells have a hormonal sensitivity correlated with the presence of specific receptors and can, therefore, serve as a selective model to study hormone action.

Current status of endocrine therapy for breast cancer

Endocrine therapy is usually indicated prior to chemotherapy as the first line therapy for metastatic breast cancer patients because of its milder toxicity. Patients who respond to a first-line endocrine therapy have a high chance of responding to a second-line endocrine therapy, and thus the responders to a first-line endocrine therapy would better be treated with second or third-line endocrine therapy. In the adjuvant setting, tamoxifen (antiestrogen) has been proven to improve the prognosis of both pre- and postmenopausal estrogen receptor positive breast cancer patients, and goserelin (LH-RH agonist) has been proven to improve prognosis in premenopausal women comparable to chemotherapy (CMF). Very recently, preliminary results have indicated that anastrozole (aromatase inhibitor) is superior to tamoxifen as adjuvant treatment for estrogen receptor positive postmenopausal breast cancer patients. In addition, the recent success of tamoxifen in a chemoprevention trial seems to have ushered in a new era wherein prevention of breast cancer is much more emphasized than treatment of established breast cancer.

Risk of breast cancer with progestins: critical assessment of current data

Whether progestins protect against the risk of breast cancer or enhance that risk has been a major area of controversy over the past several years. Observational studies have reported conflicting results and experimental studies examining whether progestins exert mitogenic or anti-mitogenic actions on breast tissue report divergent results. Based upon a wide range of animal, epidemiologic and clinical data, most investigators agree that estrogens contribute to the development of breast neoplasms. However, the additional effect of progestins on this risk has been the subject of substantial discussion and controversy. A variety of experiments have been carried out using human breast cancer cells grown in vitro and as xenografts in nude mice. These studies demonstrated both mitogenic and anti-mitogenic effects depending upon the precise experimental conditions. Two potential reasons for these differences include differential metabolism of progestins into inhibitory pregnenes or stimulatory 5-alpha-reduced pregnanes or the presence of a protein (GPR 30) which allows the anti-mitogenic effects of progestins to be manifest. Based upon the conflicting nature of the results in experimental studies, we believe that only data in patients provide substantial insight into the actions of progestins on the intact human breast. Studies have now demonstrated that cell proliferation and breast density is higher during the luteal than during the follicular phase of the menstrual cycle. In postmenopausal women, long-term exposure to estrogen plus a progestin results in a marked enhancement of proliferation of the terminal duct lobular units as well as in breast density. These data, taken together, provide substantial evidence that progestins are mitogenic on the human breast when given long term to postmenopausal women. To critically evaluate the observational studies regarding breast cancer risk from progestins, we developed a set of stringent criteria for acceptance of individual studies. Four of the five studies meeting these criteria reported a greater risk of breast cancer with combination estrogen/progestin regimens than with estrogen alone. More importantly, the first randomized, prospective, controlled trial of the risk of breast cancer with an estrogen/progestin combination (the Women's Health Initiative Study) has now been published. This study reported a 26% increased relative risk of breast cancer with the estrogen/progestin combination. Based upon these data, we believe that progestins do add to the risk of breast cancer over and above that imparted by estrogen alone. The attributable risk during use for 5 years or less is small but increases logarithmically during long-term use. The majority of data regarding progestins are derived from regimens using MPA. However, we conclude from our analysis that the burden of proof regarding progestins has now shifted. One must now prove that an estrogen/progestin combination is safe with respect to breast cancer rather than having to prove it harmful.

Endocrine and intracrine sources of androgens in women: inhibition of breast cancer and other roles of androgens and their precursor dehydroepiandrosterone

Serum androgens as well as their precursors and metabolites decrease from the age of 30-40 yr in women, thus suggesting that a more physiological hormone replacement therapy at menopause should contain an androgenic compound. It is important to consider, however, that most of the androgens in women, especially after menopause, are synthesized in peripheral intracrine tissues from the inactive precursors dehydroepiandrosterone (DHEA) and DHEA sulfate (DHEA-S) of adrenal origin. Much progress in this new area of endocrine physiology called intracrinology has followed the cloning and characterization of most of the enzymes responsible for the transformation of DHEA and DHEA-S into androgens and estrogens in peripheral target tissues, where the locally produced sex steroids are exerting their action in the same cells in which their synthesis takes place without significant diffusion into the circulation, thus seriously limiting the interpretation of serum levels of active sex steroids. The sex steroids made in peripheral tissues are then inactivated locally into more water-soluble compounds that diffuse into the general circulation where they can be measured. In a series of animal models, androgens and DHEA have been found to inhibit breast cancer development and growth and to stimulate bone formation. In clinical studies, DHEA has been found to increase bone mineral density and to stimulate vaginal maturation without affecting the endometrium, while improving well-being and libido with no significant side effects. The advantage of DHEA over other androgenic compounds is that DHEA, at physiological doses, is converted into androgens and/or estrogens only in the specific intracrine target tissues that possess the appropriate physiological enzymatic machinery, thus limiting the action of the sex steroids to those tissues possessing the tissue-specific profile of expression of the genes responsible for their formation, while leaving the other tissues unaffected and thus minimizing the potential side effects observed with androgens or estrogens administered systemically.

Medroxyprogesterone acetate decreases secretion of interleukin-6 and parathyroid hormone-related protein in a new anaplastic thyroid cancer cell line, KTC-2

A new thyroid cancer cell line, KTC-2, was established from the malignant pleural effusion of a patient with recurrent thyroid cancer associated with anaplastic transformation from thyroid papillary cancer. Karyotype analysis showed a mode of 109 chromosomes. Subcutaneous cell injections produced small regressing tumors in athymic or severe combined immunodeficiency disorders (SCID) mice. Histologic examination showed anaplastic tumor cells surrounded by prominent mononuclear cells. An expression of thyroglobulin, thyroid transcription factor-1, and PAX-8 but not thyroid peroxidase and thyrotropin (TSH) receptor was detected. Biochemical analysis revealed secretion of interleukin (IL)-6, parathyroid hormone-related protein (PTHrP), and granulocyte-macrophage colony-stimulating factor. All the cytokines are known to induce paraneoplastic syndromes in patients with anaplastic thyroid cancer. Our previous studies revealed that medroxyprogesterone acetate (MPA) reduces secretion of IL-6 and PTHrP from human breast cancer cells. To investigate the regulatory mechanisms of secretion of these cytokines, MPA was administered to the KTC-2 cells. MPA dose-dependently decreased the secretion and mRNA expression of IL-6 and PTHrP. Expression of androgen receptor and glucocorticoid receptor (GR) but not progesterone receptor was detected. Dexamethasone but not dihydrotestosterone and progesterone decreased IL-6 and PTHrP secretion. These findings suggest that MPA decreases IL-6 and PTHrP secretion as a glucocorticoid mediated by GR in the KTC-2 cells. This KTC-2 cell line may be a suitable model for developing new strategies against paraneoplastic syndromes caused by anaplastic thyroid cancer.

Characterisation of gene expression patterns in 22RV1 cells for determination of environmental androgenic/antiandrogenic compounds

Alteration of androgen receptor function due to hormonally active compounds in the environment, may be responsible for impaired reproductive function in aquatic wildlife. Based on human prostate carcinoma 22RV1 cells, a cell culture expression system was established to test effects of putative androgenic/antiandrogenic compounds on endogenous gene expression. 22RV1 cells were shown to express human androgen receptor, but not human progestin (hPR) or human oestrogen receptor (hER) alpha and beta. Six androgen-regulated genes (ARGs) were chosen to determine androgenic/antiandrogenic action using highly sensitive real-time RT-PCR. Results showed that gene expression is altered in a time-dependent manner. After stimulation of cells by DHT (10nM), synthetic androgen R1881 (1 nM), or organic pesticides (difenoconazole, fentinacetate, tetramethrin) TMPRSS2 mRNA expression was down-regulated by the factor 0.6 after 24h of DHT treatment. Similar results were obtained when cells were assayed for mRNA expression of PSA after fentinacetate and R1881 stimulation. In contrast, TMPRSS2 expression was up-regulated by the factor 0.9 when cells were stimulated by tetramethrin. Final goal of the work is a sensitive determination of differential gene expression by different compounds under study, achievement of substance-specific expression patterns and function related analysis of potential androgens/antiandrogens.

Evidence that chlormadinone acetate exhibits antiandrogenic activity in androgen-dependent cell line

Chlormadinone acetate (CMA), like other 17-hydroxyprogesterone derivatives, is thought to be a potential antiandrogen on the basis of its effect on spontaneous benign prostatic hyperplasia (BPH) in dogs. This work was undertaken to find out whether CMA presents antiandrogen activity in human androgen-dependent cell line. For this purpose, we used PALM cells, the PC-3 cell line stably transfected with human androgen receptor and a luciferase gene under transcriptional control of MMTV. Potential antiandrogenic activity was compared with that of cyproterone acetate (CPA), a standard steroidal antiandrogen. Both compounds were tested in competitive binding assays at 37 degrees C in the presence of 1 nM of [3H] R1881, a synthetic and non-metabolizable androgen. Their impact on AR transcriptional activity was evaluated by the measure of luciferase activity in the presence of R1881 with increasing concentrations of CMA or CPA (10(-8)-10(-6) M). In whole cell binding assays, competitive studies revealed that the Ki for CMA was 3.3 +/- 1.5 x 10(-8) M (versus 7.2 +/- 1.3 x 10(-8) M for CPA). Inhibition of AR transcriptional activity was 40 +/- 5% for CMA (3 x 10(-7) M) versus 59 +/- 6% for CPA at the same concentration. Moreover, CMA caused a slower import of green fluorescent protein (GFP)-AR to the nuclei of COS-7 cells than R1881. These data show that CMA exerted a competitive binding for AR and significantly decreased the AR transcriptional activity. In conclusion, this synthetic progestin presents simultaneous antiandrogenic activity that could be helpful as a new therapeutic option in women with luteal defect along with clinical signs of hyperandrogenism.

Development of an immuno-immobilized androgen receptor assay (IRA) and its application for the characterization of the receptor binding affinity of different pesticides

Pesticides are synthetic chemicals used not only for improving food and feed production but also for the protection of materials and of human health and well-being. Some of these substances are suspected for adverse effects attributable to an interaction with the endocrine system of vertebrates by mimicking or inhibiting endogenous hormones. One of the biological targets important in this relation is the androgen receptor (AR). To be able to screen environmental samples for the presence of compounds which might interfere with androgen action, we aimed to develop a receptor assay based on recombinant human AR (rhAR). We herein describe an rhAR assay in which the receptor is immobilized in microtiter plates via a specific antibody. The assay can be used for high throughput screening of chemicals spread into the environment. 29 of the most recommended pesticides of the Federal Country Hessen, Germany, were tested for their ability to displace [3H]-DHT bound to the rhAR. This evaluation included the major part of the most common herbicides, insecticides and fungicides and covered three potential groups of endocrine disrupting chemicals. For 28 of the substances evaluated, the relative binding affinity to the rhAR was below 0.1% when compared to dihydrotestosterone (DHT) (100%), only fentinacetate exhibited an affinity of 1.42%. An exchange assay indicated that the binding inhibition was reversible. In consequence, fentinacetate seems to be a hormonally active substance which may be present in vegetables or fish, but also on clothing. We conclude that further investigations on this compound and its metabolites are necessary.

Roles of androgens in the development, growth, and carcinogenesis of the mammary gland

Androgens influence the development and growth of the mammary gland in women. Treatment of animals and cultured cells with androgens has either inhibitory or stimulatory effects on the proliferation of mammary epithelia and cancer cells; the mechanisms for these dual functions are still not very clear and are discussed in this review. Epidemiological data suggest that, similar to increased estrogens, elevated androgens in serum may be associated with the development of breast cancer. Experiments in rodents have also shown that simultaneous treatment of androgen and estrogen synergizes for mammary gland carcinogenesis. Similar synergistic effects of both hormones have been observed for carcinogenesis of the uterine myometrium of female animals and for carcinogenesis of the prostate and deferens of males. There are also clinical and experimental indications for a possible association of elevated levels of both androgens and estrogens with the development of ovarian and endometrial cancers. A hypothesis is thus proposed that concomitant elevation in both androgens and estrogens may confer a greater risk for tumorigenesis of the mammary gland, and probably other female reproductive tissues than an elevation of each hormone alone.

Characterisation of the affinity of different anabolics and synthetic hormones to the human androgen receptor, human sex hormone binding globulin and to the bovine progestin receptor

For the steroidal growth promoters trenbolone acetate (TBA) and melengestrol acetate (MGA) neither the complete spectrum of biological activities nor the potential endocrine disrupting activity of their excreted metabolites in the environment is fully understood. The potency of these substances in [3H]dihydrotestosterone ([3H]-DHT) displacement from the recombinant human androgen receptor (rhAR) and from human sex-hormone binding globulin (hSHBG) was evaluated. In addition, the potency for [3H]-ORG2058 displacement from the bovine uterine progestin receptor (bPR) was tested. For comparison, different anabolics and synthetic hormones were also tested for their binding affinities. For 17beta-trenbolone (17beta-TbOH), the active compound after TBA administration, an affinity the rhAR similar to dihydrotestosterone (DHT) and a slightly higher affinity to the bPR than progesterone were demonstrated. The affinity of the two major metabolites, 17alpha-trenbolone and trendione, was reduced to less than 5% of the 17beta-TbOH-value. The affinity of these three compounds and of MGA to the hSHBG was much lower compared with DHT. MGA showed a 5.3-fold higher affinity than progesterone to the bPR but only a weak affinity to the rhAR. The major MGA metabolites have an affinity to the bPR between 85% and 28% of the affinity of progesterone. In consequence, MGA and TBA metabolites may be hormonally active substances, which will be present in edible tissues and in manure. We conclude that detailed investigations on biodegradation, distribution and bio-efficacy of these substances are necessary.

Induction of estrogen receptor-alpha and -beta activities by synthetic progestins

The cellular action of steroid hormones is mediated by specific receptors. Recently, two different estrogen receptors (ER), alpha and beta, have been cloned with a specific tissue distribution. Active estrogen as well as active progestin are compounds of oral hormonal contraceptives and hormone replacement therapy. To examine the regulation of ER-alpha and -beta activities after treatment with synthetic progestins and synthetic and natural estrogens, COS 7 cells were transfected with the vector expressing ER-alpha and -beta in combination with a luciferase reporter vector. ER-alpha activity was upregulated in the presence of synthetic progestins in a dose-dependent manner. Norethisterone, norethynodrel and desogestrel proved to be the most potent stimulatory agents of ER-alpha expression. On the other hand, not all progestins exhibited a stimulatory action on ER-beta activity. Only norgestrel, levonorgestrel, norethynodrel and norethisterone induced ER-beta-activating functions in a dose-dependent manner. Luciferase activity due to estrogen stimulation served as a positive control. Our results indicate that progestins have different effects on the activities of ER-alpha and -beta.

Androgen receptor agonist activity of the synthetic progestin, medroxyprogesterone acetate, in human breast cancer cells

Medroxyprogesterone acetate (MPA), which is frequently used as second line hormonal therapy for the treatment of metastatic breast cancer, binds with high affinity to the progesterone receptor (PR). However, the androgenic side-effects of MPA suggest that it may also activate androgen receptor (AR) regulated pathways. Treatment of the human breast cancer cell lines MDA-MB-453, ZR-75-1 and T47-D with high dose (100 nM) MPA resulted in 26-30% inhibition of cell growth, which was partially reversed by co-treatment with a 10-fold excess of the synthetic antiandrogen, anandron. Scatchard analysis demonstrated specific, high affinity (non-PR) binding of [3H]MPA to cytosols prepared from the PR-/AR+ MDA-MB-453 and PR+/AR+ ZR-75-1, but not the PR-/AR- BT-20 breast cancer cell lines. Competition of [3H]MPA binding to MDA-MB-453 cytosols by equimolar concentrations of androgens (5alpha-dihydrotestosterone (DHT), R1881) and the antiandrogen, anandron was consistent with binding of MPA to the AR. In ZR-75-1 cell cytosol fractions, DHT, R1881 and anandron only partially competed out [3H]MPA binding, suggesting that androgens displace [3H]MPA binding to AR but not to PR. Induction by MPA of AR transactivation was demonstrated in MDA-MB-453 and ZR-75-1 cells, and in the CV-1 cell line transfected with a full-length AR. In these cell lines the increased activity of the androgen responsive reporter gene (MMTV-CAT) by 1 nM MPA was fully (MDA-MB-453, CV-1) or partially (ZR-75-1) inhibited by co-culture with 1 microM anandron. These findings indicate that MPA is an AR agonist and suggest that the in vivo effects of MPA in breast cancer patients may in part be mediated by the AR.

Self-injurious behavior is decreased by cyproterone acetate in adult male rhesus (Macaca mulatta)

Self-injurious behavior (SIB) presents a serious problem in laboratory macaques that cannot be socially housed for scientific reasons and among institutionalized children and adults where it is often associated with different forms of brain dysfunction. We have experienced limited success in reducing SIB in macaques by enhancing their environment with enrichment devices. Psychotropic drugs also help, but problems are associated with their use. Because sexual and aggressive behavioral problems in men have been treated with progestational drugs, we tested the efficacy of cyproterone acetate (CA, 5-10 mg/kg/week) on reducing SIB in 8 singly housed, adult male rhesus macaques. The main findings were: (1) SIB and other atypical behaviors were significantly reduced during CA treatment; (2) serum testosterone was significantly reduced during CA treatment; (3) cerebral spinal fluid (CSF) levels of 5HIAA and HVA, metabolites of serotonin and dopamine, respectively, declined significantly during CA treatment; (4) the duration of SIB positively correlated with levels of 5HIAA in CSF; but (5) sperm counts were not reduced during treatment. Thus, CA was a partially effective treatment (3 months) for adult male macaques whose behavioral problems include SIB. In summary, CA reduced SIB, overall aggression, serum testosterone, CSF 5HIAA, and CSF HVA. We hypothesized that the progestin activity of CA represses the hypothalamic gonadal axis and decreases testosterone, which in turn decreases SIB. In addition, we speculate that the decrease in 5HIAA and HVA in CSF may have been caused by progestins decreasing the activity of MAO. Therefore, the reduction of SIB may also be related to an increase in the availability of active monoamines in the CNS.

Progestins and breast cancer

In the last years there has been an extraordinary development in the synthesis of new progestins. These compounds are classified, in agreement with their structure, in various groups which include progesterone, retroprogesterones, 17alpha-hydroxyprogesterones, 19-norprogesterones, 17alpha-hydroxyprogesterone derivatives, androstane and estrane derivatives. The action of progestins is a function of many factors: its structure, affinity to the progesterone receptor or to other steroid receptors, the target tissue considered, the biological response, the experimental conditions, dose, and metabolic transformation. The information on the action of progestins in breast cancer patients is very limited. Positive response with the progestins: medroxyprogesterone acetate and megestrol acetate was obtained in post-menopausal patients with advanced breast cancer. However, extensive information on the effect of progestins was obtained in in vitro studies using hormone-dependent and hormone-independent human mammary cancer cell lines. It was demonstrated that in the hormone-dependent breast cancer cells, various progestins (nomegestrol acetate, tibolone, medrogestone, promegestone) are potent sulfatase inhibitory agents. The progestins can also involve the inhibition of mRNA of this enzyme. In another series of studies it was also demonstrated that various progestins are very active in inhibiting the 17beta-hydroxysteroid dehydrogenase for the conversion of estrone to estradiol. More recently it was observed that the progestins promegestone or medrogestone stimulate the sulfotransferase for the formation of estrogen sulfates. Consequently, the blockage in the formation of estradiol via sulfatase, or the stimulatory effect on sulfotransferase activity, by progestins can open interesting and new possibilities in clinical applications in breast cancer.

Role of the androgen receptor in human breast cancer

Although the androgen receptor (AR)3 is often co-expressed with the estrogen receptor (ER) and progesterone receptor (PR) in human breast tumors, its role in breast cancer is poorly understood. Specific growth stimulatory and inhibitory actions of androgens have been described in human breast cancer cell lines. The mechanisms by which androgens exert these contrasting growth effects are unknown. A commonly utilized second line therapy for the treatment of advanced breast cancer is high dose medroxyprogesterone acetate (MPA). Although MPA, a synthetic progestin, was thought to act exclusively through the PR, the androgenic side-effects observed in women taking MPA suggest that its action may also be mediated in part by the AR. In support of this hypothesis, the level of AR measured by radioligand binding in primary breast tumors was correlated with the duration of response to MPA treatment following failure of tamoxifen therapy. Recent data suggest that the presence of structurally altered AR in breast cancers may account for unresponsiveness to MPA in some of these cases. Further studies are warranted to determine the role of AR mediated pathways in regulating breast tumor growth. In particular, identification of androgen-regulated genes may lead to new possibilities for the hormonal treatment of breast cancer.

Inhibitory effect of the novel anti-estrogen EM-800 and medroxyprogesterone acetate on estrone-stimulated growth of dimethylbenz[a]anthracene-induced mammary carcinoma in rats

The novel anti-estrogen EM-800 and medroxyprogesterone acetate (MPA) inhibit estrone (E1)-stimulated growth of dimethylbenz[a]anthracene (DMBA)-induced mammary tumors in a rat model. After 65 days, ovariectomy (OVX) decreased total tumor area to 9.6 +/- 3.9% of initial size, while E1 (1.0 microg, s.c., twice daily) stimulated tumor growth to 225 +/- 40.9% of initial size. Daily oral administration of 2.5 mg/kg body weight of EM-800 completely abolished E1-stimulated tumor growth. A low daily dose of EM-800 (0.25 mg/kg body weight) or MPA (1 mg, s.c., twice daily) used alone partially reversed the stimulatory effect of E1 on the growth of DMBA-induced tumors. The combination of both compounds, however, caused a more potent inhibitory effect than each compound used alone. A high dose of EM-800 completely or almost completely inhibited the E1-stimulated vaginal and uterine weights, respectively. The same dose of EM-800 completely reversed the inhibitory effect of E1 on serum luteinizing hormone levels. Uterine, vaginal and tumoral estrogen and progesterone receptor levels were reduced markedly following treatment with EM-800. Our data show that the combination of the pure anti-estrogen EM-800 with the androgenic compound MPA achieves greater inhibition of the growth of DMBA-induced mammary carcinoma than that achieved by each compound used alone.

Effects of two classes of progestagens, pregnane and 19-nortestosterone derivatives, on cell growth of human breast tumor cells: II. T47D cell lines

Two classes of progestagens, e.g. pregnane [Org 2058, progesterone (PROG), R5020, medroxyprogesterone acetate (MPA)] and 19-nortestosterone derived progestagens [norethisterone (NE), levonorgestrel (LNG), 3-ketodesogestrel (KDG), gestodene (GES), Org 30659] were studied for their effect on cell growth of two human breast tumor T47D cell lines of different origin, i.e. from ATCC (A) and Sutherland (S) et al. [Sutherland et al., Cancer Res. 48 (1988) 5084-5091]. The effect of estradiol (E2) and progestagens alone as well as the combined effect of E2 (10(-10) M) and progestagens were investigated at several dose levels. Compared with E2-induced growth at 10(-10) M, pregnane and 19-nortestosterone derived progestagens at 10(-6) M alone did enhance cell growth in T47D-A cells up to 25 and 100% respectively, whereas in T47D-S cells they did not influence growth. All these progestagens at 10(-6) M did not affect E2-induced growth in T47D-A cells, whereas in T47D-S cells they completely reduced cell proliferation at doses between 10(-10) and 10(-8) M. The involvement of progestagen (PR) and estrogen (ER) receptors with respect to growth stimulation was studied by using specific antihormones. In T47D-A cells, the antiprogestagens RU 38486 and Org 31710 could not block progestagen-induced growth. Antiestrogens, like 4-hydroxytamoxifen and ICI 164,384, inhibited the 19-nortestosterone derivative-induced cell growth by approx. 50%. Remarkably, both antiprogestagens alone could also inhibit E2-induced growth in T47D-A cells by about 50%. In T47D-S cells, E2-induced cell growth was completely blocked by both antiprogestagens and antiestrogens. Both antiprogestagens in T47D-S cells were equipotent to 4-hydroxytamoxifen and 10-fold more potent than ICI 164,384. In conclusion pregnane and 19-nortestosterone-derived progestagens stimulated cell growth in T47D-A cells at high unphysiological concentrations, whereas they did not affect cell growth in T47D-S cells. The 19-nortestosterone derivative induced growth in T47D-A cells could partially be inhibited by antiestrogens. In T47D-A cells, E2-induced cell growth was not influenced by both classes of progestagens, whereas in T47D-S cells all tested progestagens, antiprogestagens, and antiestrogens inhibited E2-induced cell growth completely. These results with T47D cells as well as those obtained previously with MCF-7 cells show that subclones of cell lines may respond differently to various types of progestagens in the presence and absence of estrogens.

Effects of two classes of progestagens, pregnane and 19-nortestosterone derivatives, on cell growth of human breast tumor cells: I. MCF-7 cell lines

The effects of two classes of progestagens, e.g. pregnane [Org 2058, medroxyprogesterone acetate (MPA), R5020, progesterone (PROG)] and 19-nortestosterone derived progestagens [3-ketodesogestrel (KDG), levonorgestrel (LNG), gestodene (GES), norethisterone (NE), Org 30659] on proliferation of three estradiol (E2)-dependent human breast tumor MCF-7 cell lines of different origin [Van der Burg (B), Litton bionetics (L) and McGrath (M)] were studied. The pregnane derivatives hardly stimulated cell growth at 10(-6) M in MCF-7 B and L cells except for Org 2058 in B cells, whereas in M cells a statistically significant growth induction was observed except for PROG. The 19-nortestosterone derivatives induced cell growth at doses at 10(-7) M or higher in all three cell lines. NE, GES and Org 30659 were more potent stimulators than KDG and LNG at 10(-7) M. E2 already showed maximal stimulation at 10(-10) M. For all three cell lines, the effects and ranking of the individual progestagens were similar. Antiprogestagens, like RU 38486 and Org 31710 could not block these stimulatory effects while antiestrogens like 4-hydroxytamoxifen and ICI 164,384 could. This suggests that cell growth by the above-mentioned progestagens occurs via an interaction with the estrogen receptor. Indeed, displacement studies with cytosol from MCF-7 M cells revealed that at very high concentrations NE, GES and Org 30659 were able to displace 50% of the radiolabelled E2, while KDG and LNG could not. Relative binding affinities (RBAs) were 0.010, 0.025 and 0.015% for NE, GES and Org 30659, respectively. The effect of the two classes of progestagens on cell proliferation was also investigated at several dose levels in combination with E2 (10(-10) M) in the MCF-7 B cell line. This resulted in a statistically significant inhibition of cell growth with R5020, MPA and most of the 19-nortestosterone derivatives at concentrations of 10(-8) M. Org 2058 and NE did not have any influence on E2-induced growth. The inhibitory effects could not be blocked by antiprogestagens. In summary these studies with 3 subclones of MCF-7 cells show that the pregnane derived progestagens stimulate growth only in one subclone, whereas the 19-nortestosterone derived progestagens do so in all three subclones. The progestagens possess estrogenic activity only at high pharmacological doses, being 10,000 times weaker than estradiol. In combination with estrogens most progestagens gave a reduction of E2-stimulated growth in the B subclone.

Inhibitory effect of a steroidal antiestrogen (EM-170) on estrone-stimulated growth of 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary carcinoma in the rat

Recently, compounds having pure antiestrogenic activity have become available. In this study, we examined the activity of the new steroidal antiestrogen EM-170 (N-n-butyl, N-methyl-11-(16' alpha-chloro-3',17' alpha-dihydroxy-estra-1',3',5'-(10')-trien-7' alpha-yl) undecanamide) on the growth of 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary carcinoma stimulated by treatment with estrone (E1), a steroid known to play an important role as precursor of 17 beta-estradiol (E2), especially in postmenopausal women. Twenty-five days after ovariectomy (OVX), tumor volume in control OVX animals decreased to 51.4 +/- 11% of the initial volume; treatment with E1, administered by Silastic implants, stimulated tumor growth to 179 +/- 21%. Treatment with the antiestrogen EM-170 at a dose of 200 micrograms (twice daily) not only completely reversed the stimulatory effect of E1, but also inhibited tumor growth to 30.5 +/- 9.6%, an effect that is 41% (P < 0.01 vs OVX control) greater than that of ovariectomy alone. At a relatively low dose of 40 micrograms (twice daily), 20 days of treatment with EM-170 reversed by 55% the stimulatory effect of E1 (1.0 micrograms, subcutaneously, twice daily) on tumor growth in OVX animals. On the other hand, the antiestrogen also induced a significant inhibitory effect on 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) activity in the DMBA-induced mammary tumors, an effect that is in agreement with the marked reduction caused by the same treatment on tumor estradiol (E2) levels in E1-treated OVX animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Megestrol-induced Cushing's syndrome

This case describes the first report of a patient developing Cushing's syndrome whilst being treated with the synthetic progestogen, megestrol acetate (Megace). Drugs are the commonest cause of Cushing's syndrome. Some synthetic progestogens are known to have glucocorticoid activity at high doses. On structural grounds neither megestrol nor its major metabolites would be expected to interact with the glucocorticoid receptor, through the manufacturers report that it may have 'weak glucocorticoid activity'.

Effects of progestagens and Org OD14 in in vitro and in vivo tumor models

Sex steroids, in particular estradiol (E2) and progesterone (P4), play, together with other hormones and growth factors, a role in the development of normal breast tissue. The effect of four progestagens (norethisterone, 3-ketodesogestrel, gestodene and P4) and Org OD14, a steroid with weak estrogenic, progestagenic and androgenic properties were studied on growth of breast tumor cells in vitro using two subclones of MCF-7 (H and A) and T47D (S and A) cells. In addition, we investigated the effects of 3-ketodesogestrel, gestodene and Org OD14 on the growth of 7,12-dimethylbenz(a)anthracene(DMBA)-induced mammary tumors in rats. In the in vitro assays with MCF-7 cells norethisterone, 3-ketodesogestrel and gestodene stimulated growth only at high doses (> or = 10(-7) M), whereas P4 had no effect. Gestodene was more potent than 3-ketodesogestrel and norethisterone. Org OD14, stimulated cell growth at a dose of 10(-8) M, while E2 is active at 10(-10) M. In T47D-A cells similar effects were found, but the subclone S did not respond to the progestagens and Org OD14. The two T47D subclones also reacted differently to progestagens during growth stimulation with E2. In T47D-S the progestagens and Org OD14 inhibited, while in T47D-A these compounds did not modulate the effect of E2. In the DMBA model we found that gestodene and 3-ketodesogestrel were able to inhibit tumor growth to the same extent. Surprisingly, Org OD14 was even more effective in the DMBA model using the therapeutic approach. Using the prophylaxic approach tumor development was delayed and tumor growth was strongly suppressed. The inhibitory effects of Org OD14 on tumor growth in the DMBA model may be attributed to its mixed hormonal profile. From these studies we conclude that different cell lines and even subclones thereof respond quite differently to steroids. Both in vitro and in vivo studies are required to judge whether synthetic steroids might be involved in an increased risk for the development of breast tumors.

Synthetic progestins induce proliferation of breast tumor cell lines via the progesterone or estrogen receptor

Proliferation of the human breast tumor cell lines T47D and MCF7 was stimulated by high concentrations (10(-6) M) of the synthetic progestins gestodene and 3-ketodesogestrel, but not by Org2058, comparable to the stimulation by low dosages of estradiol (10(-10) M). At physiological concentrations of the progestins (10(-10) M) only T47D cells responded. Using specific antihormones it was shown that the effect at pharmacological dosages is mediated by a crossreaction of these compounds with the estrogen receptor (ER), while the stimulation of T47D cells at physiological concentrations seems progesterone receptor (PR) mediated. This was further substantiated using transient transfection assays with ER- and PR-inducible reporter constructs and mRNA induction of the ER- and PR-target genes pS2 and fatty acid synthetase, respectively. Using a whole cell ligand binding assay, 20-fold higher amounts of PR were measured in T47D compared to MCF7 cells. This was in line with a much higher PR-dependent transactivation in T47D cells and suggests that the level of transcriptionally active PR is a major determinant for the response to physiological concentrations of progestins in human breast cancer cells.

Controlled release low dose medroxyprogesterone acetate (MPA) inhibits the development of mammary tumors induced by dimethyl-benz(a) anthracene in the rat

Medroxyprogesterone acetate (MPA) is well recognized to have beneficial effects for the treatment of advanced breast cancer which are comparable to those achieved with other forms of endocrine therapy. Using mammary tumors induced in the rat by dimethylbenz(a)anthracene (DMBA) as a model, we have studied the possibility that low dose MPA could prevent the development of these tumors. Single subcutaneous injection of Depo-Provera (crystalline suspension of MPA) or MPA encapsulated in biodegradable microspheres of 50:50 poly[DL-lactide-co-glycolide] was given 7 days before oral DMBA. While 63% of intact animals developed palpable mammary tumors within 85 days after DMBA administration, tumor incidence decreased to 28% and 23% in animals who had received 30 mg and 100 mg of Depo-Provera, respectively. The same amounts of MPA delivered in microspheres caused a further decrease in tumor incidence to respective values of 7% and 6%. Average tumor area, on the other hand, decreased from 4.89 cm2 in intact rats to about 0.75 (0.57-0.88) cm2 and approximately 0.20 (0.14-0.22) cm2 in the Depo-Provera and microsphere-treated groups, respectively. Using the 50:50 formulation of poly[DL-lactide-co-glycolide] designed to release MPA at a constant rate for a 4-month period, the serum MPA concentration at 3 months was measured at 4.99 +/- 0.43 ng/ml. Such data suggest that administration of a low dose controlled-release formulation of MPA in 50:50 poly[DL-lactide-co-glycolide] microspheres could well be an efficient and well tolerated approach for the prevention of breast cancer in women.

Medroxyprogesterone acetate inhibits the proliferation of estrogen- and progesterone-receptor negative MFM-223 human mammary cancer cells via the androgen receptor

This study demonstrates for the first time, that medroxyprogesterone acetate (MPA) inhibits the proliferation of the estrogen and progesterone receptor negative mammary cancer cell line MFM-223 via the androgen receptor. MPA is a progestin, which is used in the hormonal treatment of disseminated breast cancer. It binds to the progesterone, androgen, and glucocorticoid receptor and may exert its antiproliferative effects via different receptors. MFM-223 human mammary cancer cells contain a very high level of androgen receptors (160 fmol/mg protein) and low levels of estrogen, progesterone, and glucocorticoid receptors (< 20 fmol/mg protein). This cell line provides therefore a good model system to analyze the possible role of the androgen receptor in the action of MPA avoiding interference with other steroid hormone receptors. Effective inhibition of proliferation is achieved by 10 nM MPA or 1 nM of the androgen dihydrotestosterone, corresponding well to the binding affinities of both compounds (3.6 and 0.18 nM, respectively). The involvement of the androgen receptor was confirmed by competition experiments with antiandrogens. Furthermore, MFM-DHT cells, which are an androgen resistant subline of MFM-223 cells, are also resistant to MPA. This data supports the involvement of the androgen receptor in the action of MPA and additionally rules out direct hormone-independent cytotoxic effects of MPA.