Subcellular concentrations of estrone, estradiol, androstenedione and 17 beta-hydroxysteroid dehydrogenase (17-beta-OH-SDH) activity in malignant and non-malignant human breast tissues

Obesity and overfeeding affecting both tumor and systemic metabolism activates the progesterone receptor to contribute to postmenopausal breast cancer

Obese postmenopausal women have increased risk of breast cancers with poorer clinical outcomes than their lean counterparts. However, the mechanisms underlying these associations are poorly understood. Rodent model studies have recently identified a period of vulnerability for mammary cancer promotion, which emerges during weight gain after the loss of ovarian function (surgical ovariectomy; OVX). Thus, a period of transient weight gain may provide a life cycle-specific opportunity to prevent or treat postmenopausal breast cancer. We hypothesized that a combination of impaired metabolic regulation in obese animals prior to OVX plus an OVX-induced positive energy imbalance might cooperate to drive tumor growth and progression. To determine if lean and obese rodents differ in their metabolic response to OVX-induced weight gain, and whether this difference affects later mammary tumor metabolism, we performed a nutrient tracer study during the menopausal window of vulnerability. Lean animals preferentially deposited excess nutrients to mammary and peripheral tissues rather than to the adjacent tumors. Conversely, obese animals deposited excess nutrients into the tumors themselves. Notably, tumors from obese animals also displayed increased expression of the progesterone receptor (PR). Elevated PR expression positively correlated with tumor expression of glycolytic and lipogenic enzymes, glucose uptake, and proliferation markers. Treatment with the antidiabetic drug metformin during ovariectomy-induced weight gain caused tumor regression and downregulation of PR expression in tumors. Clinically, expression array analysis of breast tumors from postmenopausal women revealed that PR expression correlated with a similar pattern of metabolic upregulation, supporting the notion that PR+ tumors have enhanced metabolic capacity after menopause. Our findings have potential explanative power in understanding why obese, postmenopausal women display an increased risk of breast cancer.

Chromosomal abnormalities and hormonal disorders of primary amenorrhea patients in Egypt

BACKGROUND

Primary amenorrhea is defined as the absence of menstruation and secondary sexual characteristics in phenotypic women aged 14 years or older. Hormonal disorders are main causes of primary amenorrhea. Common hormonal cause of primary amenorrhea includes pituitary dysfunction and absent ovarian function. The aim of this study was to estimate the incidence and types of chromosomal abnormalities in patients with primary amenorrhea in Egypt.

MATERIALS AND METHODS

Chromosomal analysis and hormonal assay were carried out on 223 patients with primary amenorrhea that were referred from different parts of Egypt to Cytogenetic laboratory of Genetic Unit, Children Hospital Mansoura University, from July 2008 to December 2010. FISH technique was carried out in some of cases to more evaluation.

RESULTS

The frequency of chromosomal abnormalities was 46 (20.63%) in primary amenorrhea patients. The chromosomal abnormalities can be classified into four main types. (1) The numerical abnormalities of the X chromosome were detected in 23 (50 %). (2) Structural abnormalities of the X chromosome were detected in 11 (23.91%). (3) Mosaicism of X chromosome was found in 10 (21.74%). (4) Male karyotype 46, XY was presented in 2 (4.35%).

CONCLUSION

The present study showed that karyotype and FISH are necessary to detect the causes of primary amenorrhea. This study also revealed the incidence of chromosomal abnormalities in women with primary amenorrhea in Egypt is similar to that reported in previous literatures.

Menopausal transition: A possible risk factor for brain pathologic events

BACKGROUND AND OBJECTIVE

Incidence and prevalence of Alzheimer's disease (AD) are higher in postmenopausal women than in age-matched men. Since at menopause the endocrine system and other biological paradigms undergo substantial changes, we thought to be of interest studying whether (and how) the balance between some biological parameters allegedly neuroprotective (e.g. related to estrogen, dehydroepiandrosterone and CD36 functions) and others considered pro-neurotoxic (e.g. related to glucocorticoid and interleukin-6 activities) vary during lifespan in either sex in either normalcy or neurodegenerative disorders.

SUBJECTS AND METHODS

Along with this aim, we evaluated the gene expression levels of estrogen receptors (ERs), glucocorticoid receptors (HGRs), interleukin-6 (IL-6) and CD36, a scavenger receptor of class B allegedly playing a key role in the proinflammatory events associated with AD, in a population of 209 healthy subjects (73M, 106F, 20-91-year old) and 85 AD patients (36M, 49F, 65-89-year old). Results obtained were related to plasma titers of estrogens, cortisol and dehydroepiandrosterone sulfate (DHEAS). Studies were performed in peripheral leukocytes, since these cells (1) are easily obtainable by a simple blood sampling, (2) express many molecules and multiple receptors which are under the same regulatory mechanisms as those operative in the brain and (3) some of them, e.g. monocytes, share many functions with microglial cells.

RESULTS

In healthy men all the study parameters were quite stable during lifespan. In women, instead, at menopausal transition, some changes that may predispose to neurodegeneration occurred. In particular, there was (1) an up-regulation of ERs, and a concomitant increase of IL-6 gene expression, events likely due to the loss of the inhibitory control exerted by estradiol (E(2)); (2) an increase of HGR alpha:HGR beta ratio, indicative of an augmented cortisol activity on HGR alpha not sufficiently counteracted by the inhibitory HGR beta function; (3) a reduced CD36 expression, directly related to the increased cortisol activity; and (4) an augmented plasma cortisol:DHEAS ratio, widely recognized as an unfavorable prognostic index for the risk of neurodegeneration. In AD patients of both sexes, the expression of the study parameters was similar to that found in sex- and age-matched healthy subjects, thus indicating their unrelatedness to the disease, and rather a better correlation with biological events.

CONCLUSIONS

Menopausal transition is a critical phase of women's life where the occurrence of an unfavorable biological milieu would predispose to an increased risk of neurodegeneration. Collectively, the higher prevalence of AD in the female population would depend, at least in part, on the presence of favoring biological risk factors, whose contribution to the development of the disease occurs only in the presence of possible age-dependent triggers, such as beta-amyloid deposition.

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.

Physiologic effects of steroid hormones and postmenopausal hormone replacement on the female breast and breast cancer risk

Most data demonstrate that breast cancer is hormonally influenced. For the woman with no history of breast cancer, the benefits of HRT may outweigh the risks. Although it remains the standard of care to discourage hormone use in patients who have had breast cancer, future studies may result in a change of this standard. There needs to be more research into these complex hormonal interactions so that we will have a better understanding of the true risks and benefits when we attempt to advise our patients regarding the best treatment regimens for them.

Activity and gene expression of 17beta-hydroxysteroid dehydrogenase type I in primary cultures of epithelial and stromal cells derived from normal and tumourous human breast tissue: the role of IL-8

17Beta-hydroxysteroid dehydrogenase (17-HSD) type I is present and active in most breast cancer cell lines where it modulates local estrogen availability. Currently no information is available on its expression in primary cultures. We have quantitatively determined the cellular localisation of both enzyme activity and expression of the 17-HSD type I gene using a series of primary epithelial and stromal cells derived from normal and tumourous breast. Regulation of 17-HSD type I by IL-8 in tumour-derived cultures was also studied. Reversible 17-HSD activity was observed in most samples. In cultures derived from normal breast, the oxidative pathway predominated by up to 51-fold in epithelial and 28-fold in stromal cells. In tumour-derived cultures, the reductive pathway predominated by up to 24-fold in epithelial and 20-fold in stromal cultures, with no preferred direction in the remaining samples. Expression of the 17-HSD type I gene was determined by quantitative RT-PCR. Although this was constitutively expressed by all samples from both tissue types, significantly higher levels of the gene were observed in tumour-derived cultures (P = 0.008, epithelial; P < 0.0001 stromal vs corresponding normal culture). IL-8 upregulated gene expression in epithelial cells but it was downregulated in stroma. This was reflected in 17-HSD type I activity. Thus, 17-HSD type I is constitutively expressed and active in normal and tumourous breast and can be regulated by IL-8.

Steroid hormones and risk of breast cancer

BACKGROUND

More than three decades of epidemiologic studies have identified numerous risk factors for breast cancer. These factors have been estimated to account for only 20-25% of disease occurrence. However, among these factors, several are related to sex steroid hormones: sex of the affected individuals (women), early age of menarche and late age of menopause, parity, late age at first pregnancy, and obesity in postmenopausal women.

METHODS

Theoretical models and laboratory data support hormonal mechanisms of carcinogenesis, particularly as they relate to proliferation of breast ductal epithelium and terminal end bud growth and differentiation in the lobules of the breast. The recent introduction of biologic markers and molecular epidemiology allows for studies that use laboratory technology in the context of epidemiologic research.

RESULTS

This paper summarizes the epidemiologic literature on exogenous hormones, addresses the issue of endogenous steroid hormone levels and estrogen metabolism in serum and breast tissue in premenopausal and postmenopausal women with and without cancer, speaks to the cellular mechanisms of action of estrogen and progesterone, and highlights some of the biologic markers relevant to studies of breast cancer and precursor lesions, with particular emphasis on those that may be hormonally induced or altered.

CONCLUSIONS

These markers must be better defined in terms of breast cancer pathogenesis. Studies are needed to evaluate the direct effects of behavioral/environmental risk factors on relevant biomarkers as well as to assess the interactions of epidemiologic factors and biomarkers on risk of breast cancer.

Regulation of 17 beta-hydroxysteroid dehydrogenase in a newly-established human breast carcinoma cell line

UISO-BCA-1 human breast carcinoma cell lines, established and characterized in our own laboratory, were used to study both oxidative and reductive pathways of 17 beta-hydroxysteroid dehydrogenase (17 beta-OH-SDH). This enzyme has been suggested to catalyze conversion of both estrone to estradiol and estradiol to estrone. In order to determine the natural preferred enzymic pathway, the enzymic activity was assayed in intact cell monolayers. In these cells, reduction of estrone to estradiol was 7-fold higher than oxidation of estradiol to estrone. For the reductive pathway, the apparent Michaelis-Menten (Km) was 5.5 microM, and for the oxidative pathway, it was 14.3 microM. The enzymic conversion of estrone to estradiol was enhanced by 72 h treatment with estrone, estradiol and R5020, dehydroepiandrosterone, or dehydroepiandrosterone sulfate. On the other hand, oxidation of estradiol to estrone was stimulated by estradiol+R5020, but inhibited by estrone treatment. The results of the kinetic study, and regulation by various steroids in the present study, indicate that oxidation of estradiol or reduction of estrone is probably mediated via different forms of 17 beta-OH-SDH.

Oestradiol synthesis from oestrone in malignant breast epithelial cells: studies on a high affinity, 80 kDa form of oestradiol dehydrogenase

Previous studies have shown that in the breast there are multiple forms of the enzyme oestradiol dehydrogenase (E2DH), responsible for the interconversion of oestrone (E1) to oestradiol (E2). We have now re-examined oestrogen metabolism in the breast cancer cell lines (T47D and MCF-7) and have shown that steroids previously shown to inhibit the conversion of E1 to E2 in normal breast tissue failed to do so when added to growing monolayers of these malignant cells. In contrast to earlier estimates in normal breast tissues, the apparent Km for this conversion in monolayers of these malignant cells is shown here to be considerably lower, at around 50 nM. Cell free studies on these cell lines have revealed the presence of a high affinity (for E1) form of this enzyme of Mw approximately 80 kDa. The ability to detect this enzyme in soluble cell fractions appears to be critically dependent on buffer composition. Normal breast epithelial cells and adipose tissue appear to be devoid of this form of E2DH. As this form of E2DH has the highest affinity for the substrate E1 of all the forms in the breast, it is probable that this 80 kDa enzyme is responsible for the conversion of E1 to E2 in cell monolayers. If the observation holds that the 80 kDa enzyme is absent in the normal tissues, then the possibility arises that this E2DH may be linked with the neoplastic process in some breast tumours containing malignant epithelial cells of a similar type as studied here.

Immunological analysis of 17 beta-hydroxysteroid dehydrogenase in benign and malignant human breast tissue

The expression of 17 beta-hydroxysteroid dehydrogenase (17-HSD) enzyme protein was studied in benign and malignant human breast tissue using the time-resolved immunofluorometric assay (IFMA), immunoblotting and immunohistochemistry. The presence and distribution of estrogen and progestin receptors was also analyzed immunohistochemically. Cytosolic 17-HSD concentrations in malignant breast specimens were highly variable (less than or equal to 0.2-311 ng/mg protein). As was previously found for the placental enzyme, the molecular weight of the 17-HSD expressed in malignant breast tissue was 35 kDa, estimated following polyacrylamide gel electrophoresis and immunoblotting. The cellular distribution of 17-HSD was further studied by immunohistochemistry. Immunostaining for 17-HSD was observed in 71% of the benign breast lesions (fibroadenomas and cases of mastopathia chronica) and in 47% of the cancer specimens (intra-ductal carcinomas, invasive ductal carcinomas). In benign lesions, the staining was exclusively localized in the cytoplasm of epithelial cells, with no immunoreactivity in the stromal cells. The staining in the cancer specimens was also detected only in the cytoplasm of malignant epithelial cells. A strong or moderate expression of 17-HSD was related to the presence of PR in the specimen (chi 2 = 4.657, p = 0.031). However, the expression of PR was not a prerequisite for expression of 17-HSD in all the cancer specimens. Our data suggest that, in addition to the reported regulation of 17-HSD by progestins, other factors are also involved in this process in breast tissue.

Breast tumor-derived factors stimulate reduction of estrone to estradiol in nonmalignant breast tissue

This study examines the paracrine influence by human breast carcinoma cells (UISO-BCA-1) on nonmalignant breast tissue in vitro. The 17 beta-OH-SDH-mediated reductive pathway (estrone-->estradiol) was significantly increased in nonmalignant breast tissue coincubated with human breast carcinoma cells, compared to control tissues incubated in the media alone. No influence on the enzyme activity was noticed in coincubated breast cancer cells. Preincubation of breast cancer cells with estradiol (10(-8) M) significantly decreased the enzyme activity in coincubated nonmalignant breast tissue, which was restored to control levels by addition of R5020 (10(-8) M), tamoxifen (10(-6) M), or a combination of both. In nonmalignant tissues incubated in the presence of growth factor TGF alpha, enzyme activity was reduced to between 46% and 76%. No other growth factors (IGF I, IGF II, PDGF) influenced enzyme activity. In nonmalignant tissues incubated with malignant tumor cytosol, enzyme activity was increased in 16% cases, inhibited in 21%, and not significantly changed in 63%. The data from the present study suggest that factors produced by breast carcinoma cells may influence interconversion of estradiol in nonmalignant tissue. In patients, factors produced by malignant tumor mass may have paracrine influence on surrounding nonmalignant breast tissue and, thereby, may influence the estrogen availability to tumor mass.

A possible mechanism for increased breast cell proliferation by progestins through increased reductive 17 beta-hydroxysteroid dehydrogenase activity

We have investigated whether progestins may be able to regulate breast cell proliferation by altering the fraction of oestradiol relative to oestrone, using the human breast cancer cell line MCF-7. The ability of the two oestrogens, oestradiol and oestrone, to stimulate breast tumour cell proliferation was investigated. Oestradiol in concentration was of 10-fold greater proliferative potency than oestrone. The progestin MPA increased both reductive and oxidative 17 beta-hydroxysteroid oxidoreductase activity when the tissue culture media pH indicator phenol red was included in the media. When phenol red was excluded from the tissue culture media, MPA increased predominantly the reductive 17 beta-hydroxysteroid oxidoreductase activity, and to a far greater extent than in the presence of phenol red. Other progestins such as levonorgestrel, norethisterone and norethisterone acetate also increased predominantly reductive 17 beta-hydroxysteroid oxidoreductase activity in the absence of phenol red. The action of MPA on reductive 17 beta-hydroxysteroid oxidoreductase activity was increased by treatment with oestradiol to a small but significant extent. We propose that the progestational increase of reductive 17 beta-hydroxysteroid oxidoreductase activity is a possible mechanism by which progestins may increase breast cell proliferation in vivo.

Estrone sulfate and sulfatase activity in human breast cancer and endometrial cancer

Estrone sulfate (E1-S) in the serum and tissues of patients with breast cancer or endometrial cancer was measured by a direct radioimmunoassay without hydrolysis. The concentration of E1-S in breast cancer tissue was 1.64 +/- 0.28 ng/g wet wt (+/- SE), lower than in surrounding normal breast tissue (4.46 +/- 1.23). Estradiol-17 beta(E2)/E1-S was higher in endometrial cancer tissue than normal endometrial tissue. Estrone sulfatase activity in breast cancer tissue was 0.81 +/- 0.23 nmol/h/mg protein, higher than in surrounding normal breast tissue (0.35 +/- 0.11). These results suggest that E1-S, which is abundant in the peripheral circulation, is hydrolyzed by sulfatase in breast cancer tissue or endometrial cancer tissue and liberates free estrogens, which may stimulate the growth of these malignant tumors.

High dose ketoconazole: endocrine and therapeutic effects in postmenopausal breast cancer

Ketoconazole, an antifungal agent, inhibits in vitro C17-C20 lyase, an enzyme involved in androgen biosynthesis. Since adrenal and ovarian androgens are the main precursors of oestrogens in postmenopausal women, the endocrine and therapeutic effects of high dose ketoconazole (400 mg three times a day) were evaluated in 14 postmenopausal women with advanced breast cancer. Testosterone levels were suppressed significantly (37%, P less than 0.025), as was dehydroepiandrosterone sulphate, and androstenedione levels showed a similar but non-significant fall. Seventeen hydroxyprogesterone levels rose significantly, as would be expected if C17-C20 lyase was inhibited. There was no suppression of cortisol or oestrone levels. There was a small suppression of oestradiol concentrations, reflecting a decrease in its precursor, testosterone. Sex hormone binding globulin levels rose, which may be due to a decrease in testosterone. All the changes are compatible with C17-C20 lyase as a major site of action in vivo. No responses occurred in 12 patients treated with ketoconazole alone, but in 2 patients who were progressing on aminoglutethimide, testosterone levels were suppressed and in one patient a partial response occurred. Ketoconazole was poorly tolerated due to gastrointestinal toxicity. This study shows that C17-C20 lyase is a potential target for hormone therapy, and that sequential blockade of enzymes involved in oestrogen biosynthesis should be further evaluated.