estrone-sulfate and Breast-Neoplasms

Breast cancer is the most common malignancy in women with high mortality. Sensitive and specific methods for the detection, characterization and quantification of endogenous steroids in body fluids or tissues are needed for the diagnosis, treatment and prognosis of breast cancer and many other diseases. At present, non-invasive diagnostic methods are gaining more and more prominence, which enable a relatively fast and painless way of detecting many diseases. Metabolomics is a promising analytical method, the principle of which is the study and analysis of metabolites in biological material. It represents a comprehensive non-invasive diagnosis, which has a high potential for use in the diagnosis and prognosis of cancers, including breast cancer. This short review focuses on the targeted metabolomics of steroid hormones, which play an important role in the development and classification of breast cancer. The most commonly used diagnostic tool is the chromatographic method with mass spectrometry detection, which can simultaneously determine several steroid hormones and metabolites in one sample. This analytical procedure has a high potential in effective diagnosis of steroidogenesis disorders. Due to the association between steroidogenesis and breast cancer progression, steroid profiling is an important tool, as well as in monitoring disease progression, improving prognosis, and minimizing recurrence.

Topics: Androstenedione; Biomarkers, Tumor; Breast Neoplasms; Dehydroepiandrosterone; Dihydrotestosterone; Estradiol; Estrone; Female; Gas Chromatography-Mass Spectrometry; Humans; Immunoassay; Metabolic Networks and Pathways; Metabolomics; Recurrence; Tandem Mass Spectrometry

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

Topics: Antineoplastic Agents, Hormonal; Aromatase Inhibitors; Breast Neoplasms; Clinical Trials, Phase II as Topic; Dehydroepiandrosterone Sulfate; Estradiol; Estrone; Female; Fulvestrant; Humans; Neoplasms, Hormone-Dependent; Steryl-Sulfatase; Sulfonic Acids; Tamoxifen

Despite the dramatic fall in plasma estrogen levels at menopause, only minor differences in breast tissue estrogen levels have been reported comparing pre- and postmenopausal women. Thus, postmenopausal breast tissue has the ability to maintain concentrations of estrone (E1) and estradiol (E2) that are 2-10- and 10-20-fold higher than the corresponding plasma estrogen levels. This finding may be explained by uptake of estrogens from the circulation and/or local estrogen production. Local aromatase activity in breast tissue seems to be of crucial importance for the local estrogen production in some patients while uptake from the circulation may be more important in other patients. Beside aromatase, breast tissue expresses estrogen sulfotransferase and sulfatase as well as dehydrogenase activity, allowing estrogen storage and release in the cells as well as conversions between estrone and estradiol. The activity of the enzyme network in breast cancer tissue is modified by a variety of factors like growth factors and cytokines. Aromatase inhibitors have been used for more than two decades in the treatment of postmenopausal metastatic breast cancer and are currently investigated in the adjuvant treatment and even prevention of breast cancer. Novel aromatase inhibitors and inactivators have been shown to suppress plasma estrogen levels effectively in postmenopausal breast cancer patients. However, knowledge about the influence of these drugs on estrogen levels in breast cancer tissue is limited. Using a novel HPLC-RIA method developed for the determination of breast tissue estrogen concentrations, we measured tissue E1, E2 and estrone sulfate (E1S) levels in postmenopausal breast cancer patients before and during treatment with anastrozole. Our findings revealed high breast tumor tissue estrogen concentrations that were effectively decreased by anastrozole. While E1S was the dominating estrogen fraction in the plasma, estradiol was the estrogen fraction with the highest concentration in tumor tissue. Moreover, plasma estrogen levels did not correlate with tissue estrogen concentrations. The overall experience with aromatase inhibitors and inactivators concerning their influences on breast tissue estrogen concentrations is summarized.

Topics: Anastrozole; Animals; Aromatase Inhibitors; Breast Neoplasms; Enzyme Inhibitors; Estradiol; Estrogens; Estrone; Humans; Nitriles; Postmenopause; Radioimmunoassay; Triazoles

Reproductive and hormonal factors are involved in the etiology of breast cancer, but there are only a few prospective studies on endogenous sex hormone levels and breast cancer risk. We reanalyzed the worldwide data from prospective studies to examine the relationship between the levels of endogenous sex hormones and breast cancer risk in postmenopausal women.. We analyzed the individual data from nine prospective studies on 663 women who developed breast cancer and 1765 women who did not. None of the women was taking exogenous sex hormones when their blood was collected to determine hormone levels. The relative risks (RRs) for breast cancer associated with increasing hormone concentrations were estimated by conditional logistic regression on case-control sets matched within each study. Linear trends and heterogeneity of RRs were assessed by two-sided tests or chi-square tests, as appropriate.. The risk for breast cancer increased statistically significantly with increasing concentrations of all sex hormones examined: total estradiol, free estradiol, non-sex hormone-binding globulin (SHBG)-bound estradiol (which comprises free and albumin-bound estradiol), estrone, estrone sulfate, androstenedione, dehydroepiandrosterone, dehydroepiandrosterone sulfate, and testosterone. The RRs for women with increasing quintiles of estradiol concentrations, relative to the lowest quintile, were 1.42 (95% confidence interval [CI] = 1.04 to 1.95), 1.21 (95% CI = 0.89 to 1.66), 1.80 (95% CI = 1.33 to 2.43), and 2.00 (95% CI = 1.47 to 2.71; P(trend)<.001); the RRs for women with increasing quintiles of free estradiol were 1.38 (95% CI = 0.94 to 2.03), 1.84 (95% CI = 1.24 to 2.74), 2.24 (95% CI = 1.53 to 3.27), and 2.58 (95% CI = 1.76 to 3.78; P(trend)<.001). The magnitudes of risk associated with the other estrogens and with the androgens were similar. SHBG was associated with a decrease in breast cancer risk (P(trend) =.041). The increases in risk associated with increased levels of all sex hormones remained after subjects who were diagnosed with breast cancer within 2 years of blood collection were excluded from the analysis.. Levels of endogenous sex hormones are strongly associated with breast cancer risk in postmenopausal women.

Topics: Aged; Androstenedione; Breast Neoplasms; Case-Control Studies; Dehydroepiandrosterone; Dehydroepiandrosterone Sulfate; Estradiol; Estrone; Female; Hormone Replacement Therapy; Humans; Middle Aged; Prospective Studies; Risk; Sex Hormone-Binding Globulin; Testosterone; Time Factors

Topics: Arylsulfatases; Breast Neoplasms; Enzyme Inhibitors; Estradiol Dehydrogenases; Estrogens; Estrone; Female; Humans; Neoplasms, Hormone-Dependent; Steryl-Sulfatase

Breast cancer tissue contains the enzymes necessary for local synthesis of estradiol (E2) and it was demonstrated that, despite the presence of the sulfatase and its messenger in hormone-dependent and hormone-independent breast cancer cells, this enzyme operates particularly in hormone-dependent cells. Different progestins: Nomegestrol acetate, Promegestone, Tibolone (Org OD14) and its metabolites (Org-OM38, Org 4098 and Org 30126), as well as Danazol, can block the conversion of estrone sulfate to E2 very strongly in hormone-dependent breast cancer cells. The last step in the formation of E2 is the conversion of estrone (E1) to estrogen by the action of 17 beta-hydroxysteroid dehydrogenase. This activity is preferentially in the reductive direction (formation of E2) in hormone-dependent cells, but oxidative (E2-->E1) in hormone-independent cells. Using intact hormone-dependent cells, it was observed that Nomegestrol acetate. Promegestone as well as Danazol, can block the conversion of E1 to E2. Clinical trials of these "anti-enzyme" substances in breast cancer patients could be the next step to investigate new therapeutic possibilities for this disease.

Topics: 17-Hydroxysteroid Dehydrogenases; Breast Neoplasms; Estradiol; Estrone; Female; Humans; Neoplasms, Hormone-Dependent; Progesterone; Progesterone Congeners; Sulfatases; Tumor Cells, Cultured

Oestradiol (E2) is one of the most important factors supporting the growth and evolution of breast cancer; consequently, to block this hormone has been one of the main targets in recent years. The evaluation of oestrogens (oestrone, oestradiol and their sulphates) in the breast tissue of post-menopausal patients with breast cancer indicates high levels, particularly of oestrone sulphate (E1S) which is 15-25 times higher than in the plasma. Two main pathways are involved in the formation of oestrogens the sulphatase pathway which transforms E1,S into oestrone (E1), and the aromatase pathway which converts androgens into oestrogens. Comparative studies in breast cancer tissues show that the sulphatase pathway is 50-300 times more important than that of the aromatase pathway. Using intact cells and physiological concentrations of E1S (5 x 10(9)M) the conversion to oestradiol was very intense with the hormone-dependent (T-171). MCF-7) breast cancer cells, but very little or no E2 was obtained with the hormone-independent (MDA-MB-231, MDA-MB-436) cells. However, when the latter cells were homogenized, the oestrone sulphatase became very intense. This contradiction in the comparison of the sulphatase activity of the intact cell and the homogenate of the hormone-independent cells can be explained by the presence of inhibitory factors or the absence of positive factor(s) involved in the enzyme activity, which could be related to the evolution of the cancer to hormone-independence. Testing different substances, it was proven that promegestone (R-5020), and danazol, as well as decapeptyl in the presence of heparin, are very active in inhibiting sulphatase activity in hormone-dependent breast cancer cells. Using reverse transcriptase-PCR it was possible to detect the presence of oestrone sulphatase mRNA in different mammary cancer cells. The expression of this mRNA is significantly higher in T-471) and MDA-MB-231 than in the other cell lines. A correlation of this mRNA with the enzymatic activities of oestrone sulphate was observed. The progestagen, R-5020, can significantly decrease the sulphatase mRNA in MCF-7 and T-471) cells. As this progestagen can also inhibit the enzyme itself, it is suggested that the decrease in sulphatase activity by antisulphatase agents in breast cancer cells is a complex mechanism involving not only the effect on the enzyme but also the transcriptional factor(s). It is concluded that in addition to the control of aromatase, specific inh

Topics: Breast Neoplasms; Estradiol; Estrone; Female; Humans; Sulfatases

Plasma ethinylestradiol increases 47.6% when taken with ascorbic acid because of competition in producing sulfate conjugation. Thus the role of sulfates may be important. Serum and urinary estrone sulfate (E1-S) in pregnancy and non-pregnancy were analyzed. Its serum peak during the menstrual cycle was 2.67 +/- 0.37 ng/ml (mean +/- SE) and about ten times that of estradiol-17 beta. E1-S showed lower levels in malignant tissues of breast cancer and endometrial cancer. Increased sulfatase activity in the malignant tissue hydrolyzes E1-S to E1, which may develop the tumors. Serum estradiol 17-sulfate (E2-17-S) in pregnancy was first measured. As E2-17-S decreased, lipid peroxides increased. E2-17-S is converted to 2-OH or 4-OH E2-17-S, which act as lipid peroxide scavengers. Pregnancy-induced hypertension showed lower levels of E2-17-S. In vitro study using the human endothelial cell of the aorta, E2-17-S and 2-OH E2-17-S strongly suppressed lipid peroxidation, which precedes atherosclerotic change.

Topics: Adult; Aged; Aged, 80 and over; Arteriosclerosis; Breast Neoplasms; Estradiol; Estrone; Female; Humans; Lipid Peroxidation; Menstrual Cycle; Middle Aged; Pre-Eclampsia; Pregnancy; Uterine Neoplasms

One-third of the cases of breast cancer in postmenopausal women are hormone-dependent and the lesions regress upon treatment with antiestrogens or inhibition of estrogen biosynthesis. In these patients, estrogens are synthesized in extraglandular tissues from adrenal precursors and re-enter plasma to produce estrone levels of 52 +/- 6.5 pg/ml (mean +/- SEM) and estradiol concentrations of 13.1 +/- 0.7 pg/ml. However, the fact that the levels of estrogen in breast tumor tissue are an order of magnitude higher than plasma levels suggested the possibility of in situ estrogen production. To address this possibility, we measured several enzymes involved in estradiol biosynthesis in human tumors. Forty-eight of 61 tumors contained aromatase (estrogen synthetase) activity ranging from 5-80 pg/gm protein per hour. By comparison, the levels of estrone sulfatase were 10(6) higher, ranging from 0.8-125 micrograms/gm protein per hour. Because the sulfatase enzyme was of lower affinity (i.e., Km = 27 microM) than that of aromatase (i.e., 0.027 microM), the amount of estrogen formed under conditions of similar substrate concentrations was compared and found to be 10-fold higher via the sulfatase enzyme. In 41 additional tumors, the 17 beta-hydroxysteroid dehydrogenase enzyme, catalyzing the conversion of estrone to estradiol, was uniformly present. To test the biologic relevance of the estrone sulfate to estrone to estradiol pathway, estrogen-dependent nitrosomethylurea rat mammary tumors were grown in soft agar in the presence of estrone sulfate. Concentrations of estrone sulfate of 10(-6) microM significantly (p less than 0.01) stimulated colony formation in this system in which 75.5-98.6% of estrone sulfate was converted to estrone and 0.2 to 6% to estradiol. These data support the hypothesis that mammary carcinomas can synthesize estradiol in situ from circulating estrogen precursor and that local conversion is biologically important. On the basis of comparative data, the estrone sulfate to estrone to estradiol pathway is quantitatively more important than that involving androstenedione to estrone to estradiol.

Topics: 17-Hydroxysteroid Dehydrogenases; Adrenalectomy; Aminoglutethimide; Androstenedione; Animals; Aromatase; Breast Neoplasms; Estradiol; Estrogens; Estrone; Female; Humans; Hydrocortisone; Mammary Neoplasms, Experimental; Neoplasms, Hormone-Dependent; Rats; Sulfatases; Testolactone

Topics: Antibodies, Monoclonal; Breast Neoplasms; Cell Division; Cell Line; Cells, Cultured; Diethylstilbestrol; Dihydrotestosterone; Estradiol; Estriol; Estrone; Female; Humans; Immunoenzyme Techniques; Molecular Weight; Neoplasm Proteins

To describe estradiol (E2), estrone (E1), and estrone sulfate (E1S) levels during the first year of monthly triptorelin plus exemestane or tamoxifen and to assess possible suboptimal suppression while receiving exemestane plus triptorelin.. Premenopausal patients with early breast cancer on the Suppression of Ovarian Function Trial who selected triptorelin as the ovarian suppression method and were randomly assigned to exemestane plus triptorelin or tamoxifen plus triptorelin were enrolled until the target population of 120 patients was reached. Blood sampling time points were 0, 3, 6, 12, 18, 24, 36, and 48 months. Serum estrogens were measured with a highly sensitive and specific assay. This preplanned 12-month analysis evaluated E2, E1, E1S, follicle-stimulating hormone, and luteinizing hormone levels in all patients and the proportion of patients with E2 levels greater than 2.72 pg/mL at any time point during treatment with exemestane plus triptorelin.. One hundred sixteen patients (exemestane, n = 86; tamoxifen, n = 30; median age, 44 years; median E2, 51 pg/mL; 55% prior chemotherapy) started triptorelin and had one or more samples drawn. With exemestane plus triptorelin, median reductions from baseline E2, E1, and E1S levels were consistently ≥ 95%, resulting in significantly lower levels than with tamoxifen plus triptorelin at all time points. Among patients on exemestane plus triptorelin, 25%, 24%, and 17% had an E2 level greater than 2.72 pg/mL at 3, 6, and 12 months, respectively. Baseline factors related to on-treatment E2 level greater than 2.72 pg/mL were no prior chemotherapy (P = .06), higher body mass index (P = .05), and lower follicle-stimulating hormone and luteinizing hormone (each P < .01).. During the first year, most patients on exemestane plus triptorelin had E2 levels below the defined threshold of 2.72 pg/mL, consistent with levels reported in postmenopausal patients on aromatase inhibitors, but at each time point, at least 17% of patients had levels greater than the threshold.

Topics: Adult; Androstadienes; Antineoplastic Agents, Hormonal; Antineoplastic Combined Chemotherapy Protocols; Breast Neoplasms; Chemotherapy, Adjuvant; Estradiol; Estrogens; Estrone; Female; Follicle Stimulating Hormone; Humans; Luteinizing Hormone; Ovary; Tamoxifen; Triptorelin Pamoate

Although high endogenous sex hormone levels and estrogen plus progestin (E+P) therapy are associated with increased breast cancer risk, it is unknown whether pretreatment levels of sex hormones modify E+P effect on breast cancer.. We conducted a nested case-control study within the Women's Health Initiative randomized clinical trial of E+P. The trial enrolled 16608 postmenopausal women aged 50 to 79 years with intact uterus and no breast cancer history. During a mean of 5.6 years of follow-up, 348 incident breast cancer case subjects were identified and matched with 348 control subjects. Case and control subjects had their sex hormone levels measured at baseline (estrogens, testosterone, progesterone, and sex hormone-binding globulin [SHBG]) and year 1 (estrogens and SHBG) using sensitive assays. All statistical tests were two-sided.. Statistically significant elevations in breast cancer risk were seen with greater pretreatment levels of total estradiol (P trend = .04), bioavailable estradiol (P trend = .03), estrone (P trend = .007), and estrone sulfate (P trend = .007). E+P increased all measured estrogens and SHGB at year 1 (all P < .001). The effect of E+P on breast cancer risk was strongest in women whose pretreatment levels of total estradiol, bioavailable estradiol, and estrone were in the lowest quartiles. For example, the odds ratio for E+P relative to placebo was 2.47 (95% confidence interval [CI] = 1.28 to 4.79) in the lowest total estradiol quartile, compared with 0.96 (95% CI = 0.44 to 2.09) in the highest total estradiol quartile; P interaction = .04).. Women with lower pr-treatment endogenous estrogen levels were at greater risk of breast cancer during E+P therapy compared with those with higher levels. Further studies are warranted to confirm these findings.

Topics: Aged; Breast Neoplasms; Case-Control Studies; Estradiol; Estrogen Replacement Therapy; Estrogens; Estrone; Female; Follow-Up Studies; Gonadal Steroid Hormones; Humans; Incidence; Middle Aged; Odds Ratio; Postmenopause; Progesterone; Progestins; Risk Assessment; Risk Factors; Sex Hormone-Binding Globulin; Testosterone; United States; Women's Health

Menopausal hormone therapy increases mammographic density. We determined whether increases in serum estrone sulfate (E(1)S) levels during menopausal hormone therapy predict increased mammographic density.. We measured percent mammographic density and serum E(1)S levels in 428 participants of the Postmenopausal Estrogen/Progestin Interventions study who were randomly assigned to daily conjugated equine estrogen (CEE) 0.625 mg alone, CEE + daily medroxyprogesterone acetate (MPA) 2.5 mg, CEE + cyclical MPA (10 mg days 1-12 per 28-day cycle), or CEE + cyclical micronized progesterone (10 mg days 1-12). Serum E(1)S levels were determined by RIA. Information about covariates was determined by annual questionnaire. Using linear regression, we determined the association between change in E(1)S level from baseline to 12 months and change in percent mammographic density (by semiquantitative interactive threshold method).. After controlling for baseline mammographic density, age, body mass index, alcohol intake, parity, smoking, ethnicity, physical activity, and age at first pregnancy, mammographic density increased by 1.3% for every 1 ng/mL increase in E(1)S level (P < 0.0001). The association between change in E(1)S level and change in mammographic density differed by treatment group (greater effect in CEE + cyclical MPA group versus CEE group; P = 0.05). After controlling for treatment group, change in the ratio of E(1)S to E(1) was also positively associated with change in mammographic density.. Increases in serum E(1)S levels during menopausal hormone therapy are associated with increases in mammographic density. The relative contribution of E(1)S and E(1) to stimulation of breast tissue awaits further elucidation.

Topics: Biomarkers, Tumor; Breast Neoplasms; Contraceptives, Oral, Synthetic; Drug Therapy, Combination; Estrogens; Estrogens, Conjugated (USP); Estrone; Female; Follow-Up Studies; Hormone Replacement Therapy; Humans; Incidence; Mammography; Medroxyprogesterone; Menopause; Middle Aged; Progesterone; Progestins; Radioimmunoassay; Risk Factors; Surveys and Questionnaires; United States

To evaluate the influence of the third-generation aromatase inhibitor letrozole (Femara) on breast cancer tissue levels of estrone (E(1)), estradiol (E(2)), and estrone sulfate (E(1)S) in postmenopausal women undergoing primary treatment for locally advanced estrogen receptor/progesterone receptor-positive breast cancers.. Breast cancer tissue samples were collected before and following 4 months of neoadjuvant therapy with letrozole (2.5 mg o.d.), and tissue estrogen levels measured using a highly sensitive RIA after high-pressure liquid chromatography purification.. Letrozole suppressed pretreatment tumor levels of E(2), E(1), and E(1)S by 97.6%, 90.7%, and 90.1%, respectively. These data reveal that letrozole suppresses tissue estrogen levels significantly below what has previously been recorded with anastrozole (89.0%, 83.4%, and 72.9% suppression, respectively) using the same methods. To confirm the differential effect of letrozole and anastrozole on each plasma estrogen fraction, we re-analyzed plasma samples obtained from a previous intrapatient cross-over study comparing letrozole and anastrozole using an improved RIA (detection limits of 0.67, 1.14, and 0.55 pmol/L for E(2), E(1), and E(1)S, respectively). Letrozole consistently suppressed each plasma estrogen fraction below the levels recorded for anastrozole: E(2) (average suppression by 95.2% versus 92.8%; P = 0.018), E(1) (98.8% suppression versus 96.3%; P = 0.003), and E(1)S (98.9% suppression versus 95.3%; P = 0.003).. Our data reveals that letrozole (2.5 mg o.d.) is more effective compared with anastrozole (1.0 mg o.d.) with respect to tissue as well as plasma estrogen suppression in patients with postmenopausal breast cancer.

Topics: Aged; Aged, 80 and over; Anastrozole; Antineoplastic Agents; Breast Neoplasms; Chromatography, High Pressure Liquid; Estradiol; Estrogens; Estrone; Female; Humans; Letrozole; Middle Aged; Nitriles; Postmenopause; Radioimmunoassay; Triazoles

To compare the effects of anastrozole and letrozole on plasma estradiol (E2) and estrone sulfate (E1S) levels.. Fifty-four postmenopausal women with estrogen receptor-positive breast cancer receiving aromatase inhibitors (AIs) as part of their adjuvant therapy were randomly assigned to receive either 3 months of anastrozole (1 mg) followed by 3 months of letrozole (2.5 mg), both given orally once daily, or 3 months of the opposite sequence. Blood was taken at the same time and the same day of the week from each patient, before and after 3 months of each drug, and plasma levels of E2 and E1S were determined using highly sensitive radioimmunoassays.. There were 27 patients in each group. The mean age of the patients was 63 years (range, 49 to 83 years). Baseline E2 levels ranged from 3 pmol/L to 91 pmol/L with a mean of 25.7 pmol/L. Only one of 54 (2%) patients had an E2 value >or= 3 pmol/L after receiving letrozole, versus 20 of 54 (37%) patients after receiving anastrozole (P < .001). Extrapolation revealed a mean E2 level after anastrozole treatment of 2.71 pmol/L (range, 2.38 to 3.08 pmol/L). Following letrozole, it was 1.56 pmol/L (range, 1.37 to 1.78 pmol/L). Mean residual E2 was 10.1% for anastrozole and 5.9% for letrozole. Residual E1S levels were 4.6% for anastrozole and 2.0% for letrozole (P = .001).. Letrozole reduces plasma E2 and E1S levels to a significantly greater extent than anastrozole in postmenopausal women taking AIs as part of their adjuvant therapy for hormone receptor-positive breast cancer.

Topics: Adult; Aged; Aged, 80 and over; Anastrozole; Antineoplastic Agents; Breast Neoplasms; Chemotherapy, Adjuvant; Cross-Over Studies; Estradiol; Estrone; Female; Humans; Letrozole; Middle Aged; Nitriles; Postmenopause; Radioimmunoassay; Selective Estrogen Receptor Modulators; Tamoxifen; Treatment Outcome; Triazoles

Unlike estrogens plus progestagens, tibolone, a selective tissue estrogenic activity regulator, does not increase breast tenderness and mammographic density. To elucidate this, serum and breast levels of tibolone and estrogenic metabolites are measured. Postmenopausal women (n = 102) with early-stage, ER(+ve), primary breast cancer received tibolone or placebo for 14 days in an exploratory, double-blind, randomized trial (STEM carcinoma tissue). Baseline and presurgery sera were collected; tumor tissues were obtained at surgery. E(1) (estrone), E(2) (estradiol), E(1)S (estrone-sulfate), tibolone-its nonsulfated, monosulfated, and disulfated 3-hydroxymetabolites-and Delta(4)-tibolone were measured by validated gas chromatography and mass spectrometry and liquid chromatography with tandem mass spectrometry assays. More than 12 hours after the final dose, serum E(1), E(2), and E(1)S levels were unchanged with placebo, whereas tibolone significantly increased E(1)S and the E(1)S/(E(1) + E(2)) ratio. In tumors, E(1) and E(2) levels were higher than in serum, and E(1)S levels were lower, with placebo and tibolone administration. The percentage of E(1)S was about 90% in serum and 16% in tissue. Tibolone did not affect tissue levels of endogenous estrogens. Serum levels of estrogenic 3alpha- and 3beta-hydroxytibolone, progestagenic/androgenic Delta(4)-tibolone, and monosulfate metabolites were low. Serum 3alphaS,17betaS-tibolone and 3 betaS,17betaS-tibolone levels were 250 and 52 ng/mL, respectively. Tumor levels of 3alpha- and 3beta-hydroxytibolone and Delta(4)-tibolone were higher than in serum, but disulfate levels were lower. The percentage of sulfated tibolone metabolites was 99% in serum and 96% in tumor. Serum metabolite patterns of estradiol and tibolone are different from those in tissues and are compatible with neutral effects of tibolone on breast Ki67 expression.

Topics: Aged; Androstenols; Breast; Breast Neoplasms; Chromatography, Liquid; Double-Blind Method; Estradiol; Estrenes; Estrone; Female; Gas Chromatography-Mass Spectrometry; Humans; Middle Aged; Neoplasm Staging; Norpregnenes; Postmenopause; Selective Estrogen Receptor Modulators; Tandem Mass Spectrometry; Tissue Distribution

In some specific circumstances, combined hormonal therapies for breast cancer seem to be more effective than single maneuvers. In two laboratory mammary cancer models, the combination of the aromatase inactivator exemestane plus tamoxifen gives a higher response rate than is found with either agent alone. To evaluate the endocrine effects of the combination of exemestane and tamoxifen, we studied 33 postmenopausal women disease-free following primary treatments for breast cancer who were taking tamoxifen for at least 3 months.. After observation for symptoms on tamoxifen for 4 weeks, blood samples were taken and patients were begun additionally on exemestane 25 mg p.o. qd. Eight weeks later, blood samples were again taken, and exemestane was discontinued.. A decrease in alkaline phosphatase was found with exemestane treatment (P = 0.06), whereas no change in osteocalcin level was observed. A decrease in high-density lipoprotein cholesterol level was found (P = 0.0025), whereas total cholesterol, low-density lipoprotein cholesterol and triglyceride levels showed no changes with exemestane treatment. Estradiol, estrone, and estrone sulfate levels decreased to immeasurable or very low levels with exemestane treatment (all P < 0.001). No significant changes in frequencies of common drug-associated side effects, such as vasomotor symptoms or weight change, were found.. Based on the absence of adverse endocrine effects with the addition of exemestane to tamoxifen therapy observed in this study, further clinical evaluation of the efficacy of this combination is warranted.

Topics: Adult; Aged; Alkaline Phosphatase; Androstadienes; Antineoplastic Combined Chemotherapy Protocols; Aromatase Inhibitors; Breast Neoplasms; Cholesterol, HDL; Estradiol; Estrogen Antagonists; Estrone; Exanthema; Female; Hot Flashes; Humans; Middle Aged; Postmenopause; Tamoxifen; Treatment Outcome

Rodent models of human breast cancer suggest that the combination of the steroidal aromatase inhibitor exemestane with tamoxifen may have additive activity. Clinical trials combining tamoxifen with letrozole or anastrazole have shown minor pharmacokinetic drug interactions. We did an open-label crossover clinical trial of the effect of exemestane on tamoxifen pharmacokinetics.. Thirty-two postmenopausal women who were clinically disease-free following primary treatments for breast cancer receiving tamoxifen for at least 3 months were studied. Blood was collected for pharmacokinetic analysis after at least 4 months of receiving 20 mg tamoxifen daily. Subjects then began 8 weeks of oral exemestane (25 mg daily), followed by another set of blood samples.. There were no serious toxicities noted when the two drugs were combined. There was no significant effect of exemestane on the area under the plasma concentration versus time curve (AUC) of tamoxifen at steady state before [3.04 mg h/L; 90% confidence interval (90% CI), 2.71-3.44] and during exemestane treatment (3.05 mg h/L; 90% CI, 2.72-3.41). There were no significant changes in the formation of primary tamoxifen metabolites. Oral clearance of exemestane averaged 602 L/h based on an average plasma exemestane AUC of 41.5 microg h/L (90% CI, 36.7-62.6). Plasma concentrations of estradiol, estrone, and estrone sulfate decreased when exemestane was begun; estradiol concentrations consistently decreased below the limit of quantitation.. There is no pharmacokinetic interaction between tamoxifen and exemestane. No modification in the standard regimen of either drug seems to be indicated if they are used in combination. The combination of the two drugs was well tolerated during the 8-week evaluation period.

Topics: Adult; Aged; Androstadienes; Antineoplastic Agents, Hormonal; Aromatase Inhibitors; Breast Neoplasms; Drug Interactions; Estradiol; Estrone; Female; Humans; Middle Aged; Postmenopause; Tamoxifen

We conducted a pilot study assessing the effects of the selective estrogen receptor modulator, tamoxifen, on the pharmacokinetics, pharmacodynamics, and safety of the steroidal, irreversible aromatase inhibitor (AI), exemestane, when the two were coadministered in postmenopausal women with metastatic breast cancer.. Patients with documented or unknown hormone receptor sensitivity were eligible. Patients received oral exemestane at 25-mg once daily. Starting day 15, oral tamoxifen at 20-mg once daily, was added. We measured plasma concentrations of exemestane, estrone, estrone sulfate, and estradiol after 14 days of exemestane monotherapy and after approximately 4 weeks of combination therapy. The incidence and severity of adverse events were assessed by physical examination and patient reporting.. We treated 18 patients. All had received prior chemotherapy and/or hormonal therapy, eight and six, respectively, with single-agent selective estrogen receptor modulators or irreversible aromatase inhibitors; no hormonal therapy was given within 30 days of study entry. Plasma exemestane concentrations and estrone, estrone sulfate, and estradiol suppression were unchanged after approximately 4 weeks of tamoxifen coadministration. All drug-related adverse events were grades 1 or 2; none was unexpected. Although not a formal study end point, antitumor activity was noted, with two partial responses and four cases of stable disease among 17 evaluable patients after a 9-month median follow-up (range, 2.5-19 months).. This pilot study provides evidence that coadministration of tamoxifen does not affect exemestane pharmacokinetics or pharmacodynamics and that the combination is well-tolerated and active. Further clinical investigation is warranted.

Topics: Administration, Oral; Aged; Aged, 80 and over; Androstadienes; Antineoplastic Combined Chemotherapy Protocols; Breast Neoplasms; Estradiol; Estrone; Female; History, 18th Century; Humans; Middle Aged; Neoplasm Metastasis; Neoplasm Staging; Pilot Projects; Tamoxifen

To compare the efficacy, safety and tolerability of letrozole, an advanced non-steroidal aromatase inhibitor, and fadrozole hydrochloride, an older-generation drug in this class, we conducted a randomised double-blind trial in postmenopausal women with advanced breast cancer.. One hundred and fifty-seven postmenopausal women with advanced breast cancer were enrolled and randomly assigned to receive letrozole or fadrozole in a multicentre, randomised double-blind trial in Japan. One hundred and fifty-four eligible patients were treated with either letrozole 1.0 mg once daily (n = 77) or fadrozole 1.0 mg twice daily (n = 77), for a minimum of 8 weeks.. Letrozole showed a significantly higher overall objective response rate [complete response (CR) + partial response (PR)] than fadrozole (31.2% and 13.0%, respectively; P = 0.011, Fisher's exact test). Clinical benefits defined as CR, PR and stable disease (no change in status for more than 24 weeks) were also higher in patients treated with letrozole (50.6%) than fadrozole (35.1%). Letrozole was significantly superior to fadrozole in terms of the dominant lesion in soft tissue, bone and viscera (P = 0.011, stratified Mantel-Haenszel test). Median time to progression was 211 days in the letrozole group and 113 days in the fadrozole group with no significant difference (P = 0.175, log-rank test). Letrozole markedly reduced the estradiol, estrone and estrone sulfate levels in peripheral blood within 4 weeks. The suppressive effect of fadrozole on these hormone levels was insufficient. Adverse drug reactions were observed in 35.9% of the patients treated with letrozole and in 39.5% of those treated with fadrozole with no significant difference between the two groups (P = 0.74, Fisher's exact test). Most of the adverse drug reactions were rated as grade 1 or 2.. The results show letrozole at a dose of 1.0 mg once daily to be more effective in treating postmenopausal women with advanced breast cancer than fadrozole at 1.0 mg twice daily, with similar safety and tolerability profiles.

Topics: Administration, Oral; Antineoplastic Agents; Aromatase Inhibitors; Breast Neoplasms; Disease Progression; Double-Blind Method; Enzyme Inhibitors; Estradiol; Estrone; Fadrozole; Female; Humans; Letrozole; Middle Aged; Neoplasm Recurrence, Local; Nitriles; Postmenopause; Receptors, Estrogen; Receptors, Progesterone; Safety; Survival Rate; Triazoles

To compare the effects of the two novel, potent, nonsteroidal aromatase inhibitors anastrozole and letrozole on total-body aromatization and plasma estrogen levels.. Twelve postmenopausal women with estrogen receptor-positive, metastatic breast cancer were treated with anastrozole 1 mg orally (PO) and letrozole 2.5 mg PO once daily, each given for a time interval of 6 weeks in a randomized sequence. Total-body aromatization was determined before treatment and at the end of each treatment period using a dual-label isotopic technique involving isolation of the metabolites with high-performance liquid chromatography. Plasma levels of estrone (E(1)), estradiol (E(2)), and estrone sulfate (E(1)S) were determined in samples obtained before each injection using highly sensitive radioimmunoassays.. Pretreatment aromatase levels ranged from 1.68% to 4.27%. On-treatment levels of aromatase were detectable in 11 of 12 patients during treatment with anastrozole (mean percentage inhibition in the whole group, 97.3%) but in none of the 12 patients during treatment with letrozole (> 99.1% suppression in all patients; Wilcoxon, P =.0022, comparing the two drug regimens). Treatment with anastrozole suppressed plasma levels of E(1), E(2), and E(1)S by a mean of 81.0%, 84.9%, and 93.5%, respectively, whereas treatment with letrozole caused a corresponding decrease of 84.3%, 87.8% and 98.0%, respectively. The suppression of E(1) and E(1)S was found to be significantly better during treatment with letrozole compared with anastrozole (P =.019 and.0037, respectively).. This study revealed letrozole (2.5 mg once daily) to be a more potent suppressor of total-body aromatization and plasma estrogen levels compared with anastrozole (1 mg once daily) in postmenopausal women with metastatic breast cancer.

Topics: Aged; Anastrozole; Antineoplastic Agents; Antineoplastic Agents, Hormonal; Aromatase; Aromatase Inhibitors; Breast Neoplasms; Chromatography, High Pressure Liquid; Cross-Over Studies; Enzyme Inhibitors; Estradiol; Estrogens; Estrone; Female; Humans; Letrozole; Middle Aged; Nitriles; Postmenopause; Radioimmunoassay; Triazoles

Aminoglutethimide (AG) has been the most widely used aromatase inhibitor in breast cancer patients to date. Commercially, AG (Orimeten) is available as a racemate (DL-AG). Previous studies suggested the stereoisomers of AG (D-AG and L-AG) to differ considerably in their affinities and potencies to inhibit different cytochrome P-450-dependent enzymes, with D-AG being the potent aromatase inhibitor. DL-AG, apart from being an aromatase inhibitor, is known to enhance the metabolism of plasma estrone sulfate (E1S). In the present study we compared the effects of D-AG (500 mg daily) and DL-AG (1000 mg daily) on plasma estrogen levels and estrone (E1) and E1S clearance rates, determined after the injection of [14C]E1 and [3H]E1S, in a cross-over study involving 12 postmenopausal breast cancer patients. Treatment with DL-AG and D-AG suppressed plasma E1S to 18.6% and 15.0% of pretreatment levels, whereas E1 and estradiol E2 levels fell to 18.6% and 23.4% of their pretreatment levels during treatment with DL-AG and to 17.7% and 23.4% during treatment with D-AG, respectively. Thus, both treatment options suppressed all estrogens measured to a similar extent. The clearance rate of E1S increased from a mean pretreatment value of 5.9 to 14.0 and 10.0 L/h during treatment with DL-AG and D-AG, respectively (P < 0.05, comparing the two on-treatment situations), whereas the production rate of E1S decreased from a pretreatment value of 1.44 to 0.64 nmol/h with DL-AG and 0.36 nmol/h with D-AG (P < 0.05, comparing on-treatment values). These findings are consistent with the hypothesis that the D- as well as the L-form of AG may enhance the clearance rate of E1S. The finding of a higher estrogen production rate during treatment with DL-AG compared to D-AG probably reflects an increased plasma level of the estrogen precursor androstenedione (mean levels of androstenedione of 2.54 and 1.27 nmol/L during treatment with D-AG and DL-AG, respectively; P < 0.05).

Topics: Aged; Aged, 80 and over; Androgens; Antineoplastic Agents; Aromatase Inhibitors; Breast Neoplasms; Cross-Over Studies; Double-Blind Method; Enzyme Inhibitors; Estradiol; Estrone; Female; Glutethimide; Humans; Metabolic Clearance Rate; Middle Aged; Postmenopause; Stereoisomerism

The effect of exemestane (6-methylenandrosta-1,4-diene-3,17-dione) 25 mg p.o. once daily on in vivo aromatization was studied in 10 postmenopausal women with advanced breast cancer. Aromatization was determined before treatment and after 6-8 weeks on therapy by administering a bolus injection of [3H]androstenedione (500 microCi) and [14C]estrone (5 microCi) followed by measurement of the isotope ratio of urinary estrogens after high-performance liquid chromatography purification. In addition, plasma endogenous estrogens were measured with highly sensitive radioimmunoassays after separation with high-performance liquid chromatography. Treatment with exemestane suppressed whole body aromatization from a mean pretreatment value of 2.059% to 0.042% (mean suppression of 97.9%). Plasma levels of estrone, estradiol, and estrone sulfate were found to be suppressed by 94.5%, 92.2%, and 93.2%, respectively. This is the first study revealing near total aromatase inhibition in vivo with the use of a steroidal aromatase inhibitor. The observation that exemestane is a highly potent aromatase inhibitor, together with the fact that the drug is administered p.o. and causes limited side effects, suggests that exemestane is a promising new drug for the treatment of hormone sensitive breast cancer.

Topics: Administration, Oral; Androstadienes; Androstenedione; Antineoplastic Agents; Aromatase; Aromatase Inhibitors; Breast Neoplasms; Carbon Radioisotopes; Estradiol; Estrogens; Estrone; Female; Humans; Postmenopause; Tritium

Phase I studies have demonstrated that exemestane, an irreversible oral aromatase inhibitor, is able to suppress circulating oestrogen levels. In our previous experience, doses ranging from 2.5 to 25 mg induced a similar suppression of oestrogens. The aim of this study was to identify the minimum effective exemestane dose on the basis of endocrine activity. 20 evaluable postmenopausal advanced breast cancer patients were randomly given exemestane 0.5, 1, 2.5 or 5 mg, in double-blind conditions. Oestrone (E1), oestradiol (E2), oestrone sulphate (E1S), gonadotrophins, sex-hormone binding globulin and dehydroepiandrosterone sulphate serum levels were evaluated from the first day of treatment to the 7th, 14th, 28th and 56th day. Serum E1, E2 and E1S levels were suppressed by all doses starting from day 7; the degree of inhibition versus baseline was 25 up to 72% for E1, 30 up to 62% for E2 and 16 up to 52% for E1S, with higher doses achieving greater suppression; these changes were maintained over time. A significant increase in FSH and LH levels was observed for all doses. Treatment tolerability was satisfactory. The endocrine effects of exemestane appear to be dose related and 0.5 and 1 mg are ineffective for adequately suppressing circulating oestrogens.

Topics: Aged; Aged, 80 and over; Androstadienes; Antineoplastic Agents; Aromatase Inhibitors; Breast Neoplasms; Dehydroepiandrosterone Sulfate; Depression, Chemical; Double-Blind Method; Drug Administration Schedule; Estradiol; Estrogen Antagonists; Estrone; Female; Follicle Stimulating Hormone; Humans; Luteinizing Hormone; Middle Aged; Postmenopause; Sex Hormone-Binding Globulin

Clinical and endocrinological effects of exemestane (6-methylenandrosta-1,4-diene-3,17-dione; PNU 155971) were evaluated in an open Phase I study. Thirteen postmenopausal women suffering from advanced breast cancer received exemestane in escalating doses over a 12-week period. Starting on 5 mg once daily (o.d.), exemestane was subsequently escalated at 2-week intervals to 10, 25, 50, 100, and 200 mg o.d. Each patient subsequently continued treatment on the highest tolerated dose until time of progression. One patient terminated treatment after 6 days due to diarrhea that was probably not related to drug therapy, although a relationship could not be excluded. Apart from this, no serious side effects were seen during the dose escalation period. Exemestane (10 mg o.d.) caused maximal suppression of plasma estradiol (E2) and estrone (E1) to a mean of 14.6 and 5.8% of pretreatment levels, respectively, whereas 25 mg of exemestane o.d. suppressed estrone sulfate (E1S) to 8.9% of pretreatment levels. No fall in adrenal steroid levels was recorded. Exemestane (5 mg o.d.) suppressed urinary E2 and E1 to a mean of 11.9 and 12.2% of pretreatment levels, respectively. Administering exemestane at doses of 50-200 mg o.d. caused no further suppression of urinary E1, whereas urinary E2 fell to 6-7% of pretreatment levels. Median time to progression was 63 weeks. We conclude that exemestane is a well-tolerated aromatase inhibitor that effectively suppresses plasma and urinary estrogens in postmenopausal patients with breast cancer.

Topics: Aged; Alprostadil; Androgens; Androstadienes; Antineoplastic Agents; Aromatase Inhibitors; Breast Neoplasms; Dinoprostone; Dose-Response Relationship, Drug; Drug Administration Schedule; Estradiol; Estrone; Female; Follicle Stimulating Hormone; Humans; Luteinizing Hormone; Lymphatic Metastasis; Middle Aged; Neoplasm Metastasis; Postmenopause

Twelve postmenopausal women suffering from advanced breast cancer had plasma estrogens, androgens, cortisol, and gonadotropins determined before therapy and during treatment with megestrol acetate (MA) in oral doses escalated from 40 to 160 mg. The plasma clearance and production rate of estrone and estrone sulfate were determined before treatment and after 4 weeks of therapy with 160 mg MA. Treatment with MA suppressed plasma levels of dehydroepiandrosterone sulfate, androstenedione, and cortisol in a dose-dependent manner to <10% of pretreatment values. Plasma testosterone, estradiol, estrone, and estrone sulfate were suppressed to 18-29% of pretreatment values, whereas the gonadotropins were suppressed to 35-52%. The plasma clearance rates of estrone and estrone sulfate were increased by a mean value of 23.7% (P < 0.01) and 23.5% (P < 0.025), whereas the production rates were reduced by 76.7% (P < 0.0005) and 76.1% (P < 0.0005), respectively. Our findings indicate that MA causes profound suppression of adrenal steroid production but in addition suppresses ovarian secretion of androgens in postmenopausal breast cancer patients. The reduction in plasma estrogens is comparable to values obtained with commonly used aromatase inhibitors and may be responsible for its antitumor effects in breast cancer.

Topics: Administration, Oral; Aged; Androstenedione; Appetite Stimulants; Area Under Curve; Breast Neoplasms; Dehydroepiandrosterone Sulfate; Dose-Response Relationship, Drug; Estrogens; Estrone; Female; Follicle Stimulating Hormone; Humans; Hydrocortisone; Luteinizing Hormone; Megestrol Acetate; Middle Aged; Postmenopause; Testosterone

Droloxifene (3-hydroxytamoxifen) is a novel antiestrogen currently undergoing clinical investigations for treatment of breast cancer patients. We measured plasma levels of sex hormone binding globulin (SHBG) and the gonadotrophins (LH and FSH) at baseline and after 3 months on treatment in a group of fourteen postmenopausal women treated with droloxifene 40 mg daily. Plasma levels of estrone (E1), estradiol (E2) and estrone sulphate (E1S) were measured in a subgroup of eight patients. Plasma SHBG increased during treatment with droloxifene by a mean value of 16.6% (P < 0.05), while plasma levels of LH and FSH decreased by a mean value of 15.7% (n.s.) and 18.1% (P < 0.05), respectively. Plasma levels of E2 and E1 fell slightly (mean decrease 19.4 and 16.7% respectively, n.s.). On the contrary, plasma levels of E1S increased by a mean value of 23.5% (P = 0.068). The ratio of E1S to E1 and E1S to E2 increased by a mean value of 48.3% (P < 0.025) and 53.2% (P < 0.025), respectively. The effect of droloxifene 40 mg daily on plasma levels of SHBG resembles what is seen during treatment with tamoxifen but occurs to a smaller extent. Contrary to tamoxifen, droloxifene caused a minor suppression of plasma LH levels, suggesting droloxifene to have less estrogen agonistic effects on the pituitary.

Topics: Antineoplastic Agents, Hormonal; Breast Neoplasms; Estradiol; Estrogens; Estrone; Female; Follicle Stimulating Hormone; Follow-Up Studies; Humans; Luteinizing Hormone; Postmenopause; Sex Hormone-Binding Globulin; Tamoxifen; Time Factors

Plasma levels of oestradiol (Oe2), oestrone (Oe1) oestrone sulphate (Oe1S), androstenedione, testosterone, dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulphate (DHEAS), sex hormone-binding globulin (SHBG) and the gonadotrophins (FSH and LH) were determined in 20 postmenopausal women with breast cancer treated with the anti-oestrogen droloxifene (3-hydroxytamoxifen). Plasma oestrogens were measured before and after 3, 6 and 12 months of therapy. The other hormones were measured before and after 6 months of therapy. Droloxifene treatment had no significant influence on plasma levels of Oe2. Plasma levels of Oe1 and Oe1S increased during treatment (mean increase of 11.9-15.9% and 24.5-69.4% respectively after different time-intervals on treatment). The Oe1S/Oe1 and Oe1S/Oe2 ratios increased by mean values of 13.8-45.2% and 25.9-52.4% respectively. Plasma SHBG increased significantly by a mean value of 73.9%, while FSH and LH fell non-significantly by 19.7% and 20.4% respectively. Plasma levels of testosterone, androstenedione, DHEA and DHEAS all increased during treatment, but none of these alterations were of statistical significance. While the influence of droloxifene on plasma SHBG resembled that which is seen during treatment with tamoxifen, its influence on plasma oestrogens and the gonadotrophins seems to be different. Possible explanations of such differences and the clinical implications of alterations in plasma hormones during treatment with droloxifene are discussed.

Topics: Aged; Breast Neoplasms; Estradiol; Estrogen Antagonists; Estrogens, Conjugated (USP); Estrone; Female; Follicle Stimulating Hormone; Gonadal Steroid Hormones; Humans; Luteinizing Hormone; Middle Aged; Postmenopause; Sex Hormone-Binding Globulin; Tamoxifen; Time Factors

Fadrozole hydrochloride is a potent aromatase inhibitor with proven clinical effectiveness. However, its optimal dose and its effects on serum aldosterone levels/electrolyte balance have been disputed. To resolve these issues, a double-blind randomised endocrine study of three doses of fadrozole hydrochloride [0.5 mg twice daily (bd); 1.0 mg bd; 2.0 mg bd] was conducted in 80 (68 evaluable) postmenopausal patients with advanced breast cancer over a period of 3 months. There were substantial falls in the serum levels of oestradiol, oestrone and oestrone sulphate. For oestrone only, there was a significant effect of dose (on-treatment means: 0.5 mg, 38.0 pmol/l; 1.0 mg, 25.0 pmol/l; 2.0 mg, 23.9 pmol/l). All oestrogens showed a similar pattern in relation to time, with the 3-month mean being higher than those at 1 and 2 months, and this was significant for oestradiol (P = 0.012). There was an indication that complete suppression of oestradiol and oestrone was not maintained throughout the 12-h dosing period, but the data and its interpretation are complicated by a minor diurnal rhythm in these parameters. There were significant increases in 17-hydroxyprogesterone and androstenedione which may be due to a block of 11 beta-hydroxylase. There was a statistically non-significant fall in aldosterone levels (P = 0.06) during treatment (median pretreatment, 446 pmol/l; median decrease, 125 pmol/l). However, the concurrent significant fall in the plasma sodium: potassium ratio indicated that changes in aldosterone secretion did occur. None of these effects on adrenal pathways was of a degree which is likely to have clinically relevant consequences. It is concluded that fadrozole hydrochloride achieves near maximal suppression of oestrogens at 1 mg bd, and that its effects on aldosterone synthesis are unlikely to be of clinical significance.

Topics: Adult; Aged; Aged, 80 and over; Aromatase Inhibitors; Breast Neoplasms; Dose-Response Relationship, Drug; Double-Blind Method; Estradiol; Estrogens; Estrone; Fadrozole; Female; Humans; Middle Aged; Neoplasms, Hormone-Dependent; Postmenopause

Fadrozole hydrochloride at a dose of 2 mg b.i.d. has been shown to be an effective aromatase inhibitor in advanced stage breast cancer patients as determined by its ability to significantly suppress endogenous estrogen biosynthesis over a 12-week period. Continued suppression of circulating estrogen levels over a prolonged period has not yet been examined in published reports. In this study, we report the extended use of fadrozole hydrochloride at a maintenance dose of 2 mg b.i.d. in a cohort of 11 patients extending to 973 days of therapy. Results show that the degree of suppression of plasma and urinary estrogens was maintained in all patients throughout the extended period of drug use. Continued estradiol suppression of over 50% or greater from baseline was observed, as was continued suppression of estrone to over 80% from baseline. Cortisol determinations after 9 months of treatment showed no suppression from baseline. The aldosterone values and responses to cortrosyn stimulation continued to be suppressed as first noted following the initial 3 months of the core clinical trial. Objective tumor response noted in the core clinical trial did not change until disease progression. These findings suggest that fadrozole hydrochloride maintains its ability to suppress the aromatase enzyme during long term use. No observable escape from suppression of plasma and urinary estrogens occurred during prolonged treatment.

Topics: Adrenocorticotropic Hormone; Aldosterone; Breast Neoplasms; Estradiol; Estrone; Fadrozole; Female; Humans; Hydrocortisone; Neoplasm Staging

The pharmacologic inhibition of aromatase activity has been the focus of clinical trials in patients with advanced stage breast cancer. Recent developments with imidazole compounds that inhibit aromatase activity suggest their clinical use as potent inhibitors of estrogen biosynthesis in postmenopausal breast cancer patients. In this Phase I, open-label, dose-range finding study, we examined the inhibitory potency of CGS 20267 on blood and urine levels of estradiol, estrone and estrone sulfate in 8 patients with metastatic breast cancer. Studies included evaluation of adrenal and thyroid function to look for evidence of general hydroxylase inhibition at dose levels effective for aromatase blockade. Patients were administered CGS 20267 at doses of 0.1 and 0.25 mg, once a day in ascending doses over a 12-week period. Preliminary data reveal that CGS 20267 elicits a striking suppression in plasma estradiol, estrone and estrone sulphate which was observed in some patients as quickly as within 24 h of the first dose. Estrogen suppression of over 90% was achieved within 2 weeks of therapy. No alterations in either baseline or ACTH (cortrosyn) stimulated cortisol and aldosterone levels were observed through the 12 weeks of therapy. In addition, 24 h urine sodium and potassium values were not appreciably altered during therapy. We conclude that CGS 20267 is a potent, specific inhibitor of estrogen biosynthesis in postmenopausal patients with metastatic breast cancer and effectively reduces blood and urine estrogens to undetectable levels.

Topics: Aldosterone; Anti-Inflammatory Agents, Non-Steroidal; Aromatase Inhibitors; Breast Neoplasms; Cosyntropin; Estradiol; Estrogens; Estrone; Female; Humans; Hydrocortisone; Letrozole; Neoplasm Staging; Nitriles; Potassium; Sodium; Time Factors; Triazoles

Serum estradiol, estrone, estrone sulfate and sex hormone binding globulin were measured in 10 postmenopausal patients with advanced breast cancer receiving sequential treatment with medroxyprogesterone acetate and megestrol acetate. Treatment with megestrol acetate caused a non-significant reduction in serum estradiol (mean reduction of 19%, 0.05 less than P less than 0.1) but significant reductions in serum estrone (mean reduction of 20%, P less than 0.02) and serum estrone sulfate (mean reduction of 54%, P less than 0.005) compared to treatment with medroxyprogesterone acetate. In contrast, treatment with medroxyprogesterone acetate reduced serum sex hormone binding globulin more compared to treatment with megestrol acetate (mean reduction of 69%, P less than 0.01). These findings suggest that the two progestins have differential effects on serum hormone levels. The finding that treatment with megestrol acetate causes a significant reduction in serum estrone sulfate level warrants further investigations of this potentially important mechanism of action of this drug in advanced breast cancer.

Topics: Aged; Aged, 80 and over; Breast Neoplasms; Estradiol; Estrone; Humans; Medroxyprogesterone; Medroxyprogesterone Acetate; Megestrol; Megestrol Acetate; Middle Aged; Sex Hormone-Binding Globulin

The supposed mechanism of action of aminoglutethimide (AG), medical adrenalectomy, has been challenged. AG is now considered to act as an inhibitor of the aromatization of mainly adrenal androgens to estrogens in peripheral tissues and/or breast cancer itself. To further establish the AG dose required to sufficiently reduce estrogen levels in plasma and the possible role of hydrocortisone (HC) in combination with AG or by itself, postmenopausal advanced breast cancer patients received AG low (125 mg bid) or medium (250 mg bid) dose alone or combined with HC (20 mg bid) or HC alone (20 mg bid). Preliminary hormonal data show a similar reduction of serum estrone and estrone sulphate by at least some 50% at 8 wk in all treatment groups. At 6 months these effects persist except for patients treated with HC alone. In the latter a normalization of estrone levels is observed with effective suppression of adrenal androgen precursors, suggesting increased aromatase activity with prolonged glucocorticoid treatment.

Topics: Aminoglutethimide; Antineoplastic Combined Chemotherapy Protocols; Aromatase; Breast Neoplasms; Dehydroepiandrosterone; Dehydroepiandrosterone Sulfate; Dose-Response Relationship, Drug; Estrone; Female; Glucocorticoids; Humans; Hydrocortisone

Understanding intramammary estrogen homeostasis constitutes the basis of understanding the role of lifestyle factors in breast cancer etiology. Thus, the aim of the present study was to identify variables influencing levels of the estrogens present in normal breast glandular and adipose tissues (GLT and ADT, i.e., 17β-estradiol, estrone, estrone-3-sulfate, and 2-methoxy-estrone) by multiple linear regression models. Explanatory variables (exVARs) considered were (a) levels of metabolic precursors as well as levels of transcripts encoding proteins involved in estrogen (biotrans)formation, (b) data on breast cancer risk factors (i.e., body mass index, BMI, intake of estrogen-active drugs, and smoking) collected by questionnaire, and (c) tissue characteristics (i.e., mass percentage of oil, oil%, and lobule type of the GLT). Levels of estrogens in GLT and ADT were influenced by both extramammary production (menopausal status, intake of estrogen-active drugs, and BMI) thus showing that variables known to affect levels of circulating estrogens influence estrogen levels in breast tissues as well for the first time. Moreover, intratissue (biotrans)formation (by aromatase, hydroxysteroid-17beta-dehydrogenase 2, and beta-glucuronidase) influenced intratissue estrogen levels, as well. Distinct differences were observed between the exVARs exhibiting significant influence on (a) levels of specific estrogens and (b) the same dependent variables in GLT and ADT. Since oil% and lobule type of GLT influenced levels of some estrogens, these variables may be included in tissue characterization to prevent sample bias. In conclusion, evidence for the intracrine activity of the human breast supports biotransformation-based strategies for breast cancer prevention. The susceptibility of estrogen homeostasis to systemic and tissue-specific modulation renders both beneficial and adverse effects of further variables associated with lifestyle and the environment possible.

Topics: 17-Hydroxysteroid Dehydrogenases; Aromatase; Biotransformation; Breast; Breast Neoplasms; Estradiol; Estrogens; Estrone; Homeostasis; Humans; Risk Factors

The aim was to study the effects of flutamide on cell proliferation, in vivo tumour growth and steroid production in canine and human IBC cell lines. IPC-366 and SUM149 cell cultures were exposed to flutamide concentrations for 72 hours. Additionally, IPC-366 and SUM149 xenotransplanted mice were treated subcutaneously with flutamide 3 times a week for 2 weeks. Steroid hormones determination in culture media, serum and tumour homogenates (pregnenolone, progesterone, androstenedione, testosterone, dihydrotestosterone, 17β-oestradiol and oestrone sulphate) were assayed by EIA. in vitro cell proliferation percentages showed a decrease in all flutamide dosages in IPC-366 and SUM149. in vivo flutamide reduced tumour size by 55% to 65%, and metastasis rates decreased. In treated groups, androgen levels in culture media, serum and tumour homogenates were increased as oestrogen levels decreased. These results suggest that flutamide treatment inhibits cell proliferation and promotes tumour reduction by increasing androgen levels and also support future therapy approaches.

Topics: Androstenedione; Animals; Antineoplastic Agents, Hormonal; Breast Neoplasms; Cell Line, Tumor; Dihydrotestosterone; Dog Diseases; Dogs; Estradiol; Estrone; Female; Flutamide; Gonadal Steroid Hormones; Humans; Mammary Neoplasms, Animal; Mammary Neoplasms, Experimental; Mice; Mice, Inbred BALB C; Neoplasm Transplantation; Pregnenolone; Progesterone; Testosterone

No prior study to our knowledge has examined the joint contribution of a polygenic risk score (PRS), mammographic density (MD), and postmenopausal endogenous hormone levels-all well-confirmed risk factors for invasive breast cancer-to existing breast cancer risk prediction models.. We conducted a nested case-control study within the prospective Nurses' Health Study and Nurses' Health Study II including 4,006 cases and 7,874 controls ages 34-70 years up to 1 June 2010. We added a breast cancer PRS using 67 single nucleotide polymorphisms, MD, and circulating testosterone, estrone sulfate, and prolactin levels to existing risk models. We calculated area under the curve (AUC), controlling for age and stratified by menopausal status, for the 5-year absolute risk of invasive breast cancer. We estimated the population distribution of 5-year predicted risks for models with and without biomarkers. For the Gail model, the AUC improved (p-values < 0.001) from 55.9 to 64.1 (8.2 units) in premenopausal women (Gail + PRS + MD), from 55.5 to 66.0 (10.5 units) in postmenopausal women not using hormone therapy (HT) (Gail + PRS + MD + all hormones), and from 58.0 to 64.9 (6.9 units) in postmenopausal women using HT (Gail + PRS + MD + prolactin). For the Rosner-Colditz model, the corresponding AUCs improved (p-values < 0.001) by 5.7, 6.2, and 6.5 units. For estrogen-receptor-positive tumors, among postmenopausal women not using HT, the AUCs improved (p-values < 0.001) by 14.3 units for the Gail model and 7.3 units for the Rosner-Colditz model. Additionally, the percentage of 50-year-old women predicted to be at more than twice 5-year average risk (≥2.27%) was 0.2% for the Gail model alone and 6.6% for the Gail + PRS + MD + all hormones model. Limitations of our study included the limited racial/ethnic diversity of our cohort, and that general population exposure distributions were unavailable for some risk factors.. In this study, the addition of PRS, MD, and endogenous hormones substantially improved existing breast cancer risk prediction models. Further studies will be needed to confirm these findings and to determine whether improved risk prediction models have practical value in identifying women at higher risk who would most benefit from chemoprevention, screening, and other risk-reducing strategies.

Topics: Adult; Aged; Biomarkers, Tumor; Breast Density; Breast Neoplasms; Case-Control Studies; Estrogen Replacement Therapy; Estrone; Female; Hormones; Humans; Incidence; Middle Aged; Models, Biological; Multifactorial Inheritance; Polymorphism, Single Nucleotide; Postmenopause; Premenopause; Prolactin; Prospective Studies; Risk Factors; Testosterone; United States

In this work, we studied indolium and benzothiazolium pentamethine salts 1-3 as novel type of receptors for the recognition of sulphated signalling molecules (sulphated steroids: oestrone, pregnenolone and cholesterol sulphate). A recognition study was performed in an aqueous medium (1mM phosphate buffer (H2O:MeOH; 99:1 (v/v))) at pH 7.34. The tested salts displayed a high affinity for these sulphated analytes, mainly for cholesterol sulphate. However, no interaction between the salts and control, non-sulphated sterol analytes (cholesterol and bile acid) was observed. The highest affinity for the sulphated steroids was observed for benzothiazole salt 1. This salt also displayed different spectral behaviour from that observed for carbocyanine salts 2 and 3. In this presence of cholesterol sulphate, benzothiazole salt 1 displayed significant spectral changes depending on the medium used: a blue shift in the aqueous medium and a red shift in the methanolic one (H2O:MeOH; 2:1 (v/v)). Subsequently preliminary in vivo study showed that, salt 1 significantly inhibits a growth of breast carcinoma on Nu/nu mice model.

Topics: Animals; Antineoplastic Agents; Benzothiazoles; Breast Neoplasms; Carbocyanines; Cholesterol Esters; Estrone; Female; Heterocyclic Compounds; Mice, Nude; Pregnenolone; Xenograft Model Antitumor Assays

Organic Anion Transporting Polypeptides (OATP) are a family of membrane associated transporters that facilitate estrone-3-sulphate (E3S) uptake by hormone dependent, post-menopausal breast cancers. We have established E3S as a potential ligand for targeting hormone dependent breast cancer cells, and in this study sought to prepare and investigate radioiodinated E3S as a tool to study the OATP system.. 2- and 4-Iodoestrone-3-sulfates were prepared from estrone via aromatic iodination followed by a rapid and high yielding sulfation procedure. The resulting isomers were separated by preparative HPLC and verified by (1)H NMR and analytical HPLC. Transport studies of 2- and 4-[(125)I]-E3S were conducted in hormone dependent (i.e. MCF-7) and hormone independent (i.e. MDA-MB-231) breast cancer cells in the presence or absence of the specific transport inhibitor, bromosulfophthalein (BSP). Cellular localization of OATP1A2, OATP2B1, OATP3A1 and OATP4A1 were determined by immunofluorescence analysis using anti-Na(+)/K(+) ATPase-α (1:100 dilution) and DAPI as plasma membrane and nuclear markers, respectively.. Significantly (p<0.01) higher total accumulation of 2-[(125)I]-E3S was observed in hormone dependent MCF-7 as compared to hormone independent MDA-MB-231 breast cancer cells. In contrast 4-[(125)I]-E3S did not show cellular accumulation in either case. The efficiency of 2-[(125)I]-E3S transport (expressed as a ratio of Vmax/Km) was 2.4 times greater in the MCF-7 as compared to the MDA-MB-231 breast cancer cells. OATP1A2, OATP3A1 and OATP4A1 expression was localized in plasma membranes of MCF-7 and MDA-MB-231 cells confirming the functional role of these transporters in radioiodinated E3S cellular uptake.. An efficient method for the preparation of 2- and 4-[(125)I]-E3S was developed and where the former demonstrated potential as an in vitro probe for the OATP system. The new E3S probe can be used to study the OATP system and as a platform to create radiopharmaceuticals for imaging breast cancer.

Topics: Breast Neoplasms; Cell Line, Tumor; Chemistry Techniques, Synthetic; Estrone; Hormones; Humans; Iodine Radioisotopes; Kinetics; Organic Anion Transporters; Positron-Emission Tomography; Protein Isoforms; Protein Transport; Tomography, Emission-Computed, Single-Photon

Estrone-3-sulfate (E1S) is thought to be a major estrogen precursor in estrogen receptor (ER)-positive breast cancer. Since E1S is a hydrophilic compound, the uptake of E1S into cancer cells is probably mediated by transporters, such as organic anion-transporting polypeptide (OATP, SLCO) family. In this study, we investigated the relationship between expression of OATP2B1 and cell proliferation in ER-positive breast cancer. Cell-based assays were carried out in MCF-7 cells both with and without overexpression of OATP2B1. Normal breast and tumor tissues were collected and used in this study. Cell proliferation, ER-mediated transcriptional activities and estradiol secretion were stimulated by addition of E1S to the culture medium of MCF-7 cells. These stimulatory effects were significantly greater in MCF-7 cells overexpressing OATP2B1 than in control cells. The expression level of SLCO2B1 mRNA was significantly correlated with histological grade, Ki-67 labelling index and mRNA expression of steroid sulfatase. The expression level of SLCO2B1 mRNA in luminal B-like cancers was higher than that in luminal A-like cancers. Uptake of E1S resulted in down-regulation of ERα protein and induction of Ki-67 in MCF-7 cells. The present study suggests that OATP2B1 is involved in cell proliferation by increasing the amount of estrogen in ER-positive breast cancer cells.

Topics: Breast Neoplasms; Cell Proliferation; Dose-Response Relationship, Drug; Estradiol; Estrogen Receptor alpha; Estrone; Female; Gene Expression Regulation, Neoplastic; HEK293 Cells; Humans; Ki-67 Antigen; MCF-7 Cells; Organic Anion Transporters; RNA, Messenger; Transcription, Genetic; Transfection; Up-Regulation

High endogenous hormone levels have been associated with breast cancer and dietary factors have the potential to influence breast cancer risk through effects on hormone levels. Dietary patterns derived from reduced rank regression provide a way to identify food groups correlated with hormones and subsequently examine food patterns that may be associated with breast cancer risk. We investigated whether a dietary pattern previously correlated with estradiol and estrone sulfate was associated with breast cancer in the prospective Swedish Mammography Cohort. Among 37,004 primarily postmenopausal women diet was assessed with a food frequency questionnaire. Cox proportional hazard models were used to calculate hazard ratios (HRs) and 95% confidence intervals (95% CIs). During 15 years of follow-up 1,603 cases of breast cancer were identified. A higher estrogen dietary pattern score was associated with an increased risk of breast cancer. Women in the highest quartile of estrogen pattern score had a 29% (95% CI = 1.08-1.55) increased risk of breast cancer compared to women in the lowest quartile (p(trend) = 0.006). When the association was examined by estrogen-receptor status, it was only significant for those with estrogen-receptor-positive tumors; however, in the competing risk analysis there were no significant differences in the effect estimates by receptor subtype (p(heterogeneity) = 0.65). Our findings suggest that a dietary pattern associated with higher estrogen levels may increase breast cancer risk. However, whether the influence of this dietary pattern is through a direct effect on estrogen levels deserves further study.

Topics: Aged; Breast Neoplasms; Diet; Estradiol; Estrone; Feeding Behavior; Female; Humans; Mammary Glands, Human; Mammography; Middle Aged; Multivariate Analysis; Proportional Hazards Models; Prospective Studies; Risk Factors; Surveys and Questionnaires; Sweden

The Proline-, glutamic acid- and leucine-rich protein 1 (PELP1) is an estrogen receptor (ER) coactivator and a proto-oncogene known to be deregulated in endocrine cancers. In breast cancer, PELP1 overexpression has been associated with endocrine therapy resistance. Although PELP1 is known to be regulated by estrogens in vitro, its association with estrogen levels within the tissue of breast cancer patients has not previously been assessed. Here, we determined PELP1 mRNA expression levels in paired samples of normal and malignant breast tissue obtained from 32 postmenopausal and 11 premenopausal women. In the total sample set, PELP1 levels were higher in tumors compared to normal breast tissue (P = 0.041). Among postmenopausal women, PELP1 tumor levels correlated positively with estrone (E1) and estradiol (E2) levels in both normal tissue (r = 0.543, P = 0.003 and r = 0.601, P = 0.001, respectively) and plasma (r = 0.392, P = 0.053 and r = 0.403, P = 0.046, respectively). Analyzing all ER+ tumors (n = 26), PELP1 correlated positively with E1 and E2 in tumor tissue (r = 0.562, P = 0.003 and r = 0.411, P = 0.037, respectively) and normal tissue (r = 0.461, P = 0.018 and r = 0.427, P = 0.030, respectively) in addition to plasma E1, E2 and estrone sulphate (E1S) concentrations (r = 0.576, P = 0.003, r = 0.456, P = 0.025 and r = 0.406, P = 0.049, respectively). Finally, PELP1 correlated positively with ER mRNA (ESR1) (r = 0.553, P = 0.026) in ER+ tumors, whereas a negative association between PELP1 and ESR1 (r = -0.733, P = 0.010) was observed in ER- breast tumors. Taken together, tumor PELP1 mRNA expression is associated with estrogen levels in breast cancer, suggesting a potentially important role of PELP1 in ER+ breast cancer growth in vivo.

Topics: Adult; Breast Neoplasms; Co-Repressor Proteins; Estradiol; Estrogens; Estrone; Female; Humans; Middle Aged; Postmenopause; Premenopause; Proto-Oncogene Mas; Receptors, Estrogen; RNA, Messenger; Transcription Factors

Obesity is an independent adverse prognostic factor in early breast cancer patients, but it is still controversial whether obesity may affect adjuvant endocrine therapy efficacy. The aim of our study (ancillary to the two clinical trials Gruppo Italiano Mammella (GIM)4 and GIM5) was to investigate whether the circulating oestrogen levels during treatment with the aromatase inhibitor letrozole are related to body mass index (BMI) in postmenopausal women with breast cancer.. Plasma concentration of oestrone sulphate (ES) was evaluated by radioimmunoassay in 370 patients. Plasma samples were obtained after at least 6 weeks of letrozole therapy (steady-state time). Patients were divided into four groups according to BMI. Differences among the geometric means (by ANOVA and ANCOVA) and correlation (by Spearman's rho) between the ES levels and BMI were assessed.. Picomolar geometric mean values (95% confidence interval, n=patients) of circulating ES during letrozole were 58.6 (51.0-67.2, n=150) when BMI was <25.0 kg m(-2); 65.6 (57.8-74.6, n=154) when 25.0-29.9 kg m(-2); 59.3 (47.1-74.6, n=50) when 30.0-34.9 kg m(-2); and 43.3 (23.0-81.7, n=16) when ≥35.0 kg m(-2). No statistically significant difference in terms of ES levels among groups and no correlation with BMI were observed.. Body mass index does not seem to affect circulating oestrogen levels in letrozole-treated patients.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Agents; Aromatase Inhibitors; Body Mass Index; Breast Neoplasms; Chemotherapy, Adjuvant; Estrone; Female; Humans; Letrozole; Middle Aged; Nitriles; Postmenopause; Triazoles

Recent data have raised concern about the clinical efficacy of aromatase inhibitors in overweight and/or obese breast cancer patients. We report in vivo aromatase inhibition and plasma and tissue oestrogen levels in relation to body mass index (BMI) status among breast cancer patients treated with different aromatase inhibitors.. We compared data on in vivo aromatase inhibition (64 patients) as well as plasma and tissue oestrogen levels from patients participating in our studies to BMI values.. We found a weak positive correlation between pretreatment aromatisation level and BMI (n=64; R=0.236; p=0.060) but no correlation between on-treatment aromatisation levels or percentage aromatase inhibition and BMI within patient subgroups treated with any of a panel of aromatase inhibitors. Pre-treatment levels of plasma estradiol (p<0.001), estrone (p=0.001) and estrone sulphate (p=0.002) correlated to BMI. While on-treatment levels of plasma estrane sulphate correlated to BMI in patients on letrozole (R=0.601; p=0.001; n=25 for all) or anastrozole (n=12; R=0.611; p=0.035) therapy, letrozole suppressed plasma estrone sulphate more than anastrozole independent of BMI. No correlation between on-treatment tumour oestrogen levels and BMI was recorded.. Our unique data do not support a lack of effective aromatase inhibition in overweight patients or therefore a need for alternative therapy. The higher levels of estrogens in overweight postmenopausal breast cancer patients before and during aromatase inhibition may be due to effects of BMI on oestrogen metabolism rather than aromatisation.

Topics: Aged; Anastrozole; Androgens; Aromatase; Aromatase Inhibitors; Body Mass Index; Breast Neoplasms; Estradiol; Estrogens; Estrone; Female; Humans; Letrozole; Middle Aged; Nitriles; Outcome Assessment, Health Care; Postmenopause; Triazoles

Two-thirds of newly diagnosed hormone-dependent (HR?) breast cancers are detected in post-menopausal patients where estrone-3-sulphate (E3S) is the predominant source for tumour estradiol. Understanding intra-tumoral fate of E3S would facilitate in the identification of novel molecular targets for HR? post-menopausal breast cancer patients. Hence this study investigates the clinical expression of (i) organic anion-transporting polypeptides (OATPs), (ii) multidrug resistance protein (MRP-1), breast cancer resistance proteins (BCRP), and (iii) sulphatase (STS), 17β-hydroxysteroid dehydrogenase (17β-HSD-1), involved in E3S uptake, efflux and metabolism, respectively. Fluorescent and brightfield images of stained tumour sections (n = 40) were acquired at 4× and 20× magnification, respectively. Marker densities were measured as the total area of positive signal divided by the surface area of the tumour section analysed and was reported as % area (ImageJ software). Tumour, stroma and non-tumour tissue areas were also quantified (Inform software), and the ratio of optical intensity per histologic area was reported as % area/tumour, % area/stroma and % area/non-tumour. Functional role of OATPs and STS was further investigated in HR? (MCF-7, T47-D, ZR-75) and HR-(MDA-MB-231) cells by transport studies conducted in the presence or absence of specific inhibitors. Amongst all the transporters and enzymes, OATPs and STS have significantly (p < 0.0001) higher expression in HR? tumour sections with highest target signals obtained from the tumour regions of the tissues. Specific OATP-mediated E3S uptake and STS-mediated metabolism were also observed in all HR? breast cancer cells. These observations suggest the potential of OATPs as novel molecular targets for HR? breast cancers.

Topics: 17-Hydroxysteroid Dehydrogenases; ATP Binding Cassette Transporter, Subfamily G, Member 2; ATP-Binding Cassette Transporters; Breast Neoplasms; Cell Line, Tumor; Estrone; Female; Humans; MCF-7 Cells; Membrane Transport Proteins; Multidrug Resistance-Associated Proteins; Neoplasm Proteins; Organic Anion Transporters

Endogenous hormones are risk factors for postmenopausal breast cancer, and their measurement may improve our ability to identify high-risk women. Therefore, we evaluated whether inclusion of plasma estradiol, estrone, estrone sulfate, testosterone, dehydroepiandrosterone sulfate, prolactin, and sex hormone-binding globulin (SHBG) improved risk prediction for postmenopausal invasive breast cancer (n = 437 patient cases and n = 775 controls not using postmenopausal hormones) in the Nurses' Health Study.. We evaluated improvement in the area under the curve (AUC) for 5-year risk of invasive breast cancer by adding each hormone to the Gail and Rosner-Colditz risk scores. We used stepwise regression to identify the subset of hormones most associated with risk and assessed AUC improvement; we used 10-fold cross validation to assess model overfitting.. Each hormone was associated with breast cancer risk (odds ratio doubling, 0.82 [SHBG] to 1.37 [estrone sulfate]). Individual hormones improved the AUC by 1.3 to 5.2 units relative to the Gail score and 0.3 to 2.9 for the Rosner-Colditz score. Estrone sulfate, testosterone, and prolactin were selected by stepwise regression and increased the AUC by 5.9 units (P = .003) for the Gail score and 3.4 (P = .04) for the Rosner-Colditz score. In cross validation, the average AUC change across the validation data sets was 6.0 (P = .002) and 3.0 units (P = .03), respectively. Similar results were observed for estrogen receptor-positive disease (selected hormones: estrone sulfate, testosterone, prolactin, and SHBG; change in AUC, 8.8 [P < .001] for Gail score and 5.8 [P = .004] for Rosner-Colditz score).. Our results support that endogenous hormones improve risk prediction for invasive breast cancer and could help identify women who may benefit from chemoprevention or more screening.

Topics: Aged; Breast Neoplasms; Dehydroepiandrosterone Sulfate; Estradiol; Estrone; Female; Hormones; Humans; Logistic Models; Middle Aged; Models, Statistical; Postmenopause; Predictive Value of Tests; Prognosis; Prolactin; Reproducibility of Results; Risk Assessment; Risk Factors; Sex Hormone-Binding Globulin; Testosterone

The current study investigates the potential of estrone-3-sulphate (E3S) as a ligand for targeting Organic Anion Transporting Polypeptides (OATP), a family of membrane associated uptake transporters, for detection and diagnosis of hormone dependent breast cancers. E3S, an OATP substrate, is a predominant source of tumour estradiol in post-menopausal patients. To assess the potential of E3S as a ligand, distribution of exogenous E3S was determined at the whole body, tumour and cellular levels in murine models of hormone-dependent (MCF-7) and independent (MDA-MB-231) breast cancers. The highest levels of tumour uptake were observed at 6 h post injection (p.i) with significant difference (p = 0.04) between the level in MCF-7 (13.9±3.1%ID/g) and MDA-MB-231 (10.4±1.1%ID/g) (%ID/g: percentage of the total injected dose per gram tissue). The highest tumour-to-blood ratios (MCF-7∶7.4±1.2; MDA-MB-231∶9.1±2.1) were observed at 48 p.i., and highest tumour-to-muscle ratios (MCF-7∶10.7±1.5; MDA-MB-231∶3.8±0.7) were observed at 6 h p.i. Analogous to total tumour uptake, ex vivo tumour cell uptake at 2 h p.i. was 6 fold higher in MCF-7 in comparison to MDA-MB-231 tumour cells. Blocking studies, conducted by pre-administration of 100-fold excess E3S, resulted in significantly lower (MCF-7: p = 0.01; MDA-MB-231: p = 0.02) tumour uptake in both xenograft models, suggesting the involvement of an active carrier-mediated process. The expression of OATP1A2 was detected in tumour sections from both xenografts, with significantly higher expression (p = 0.002) in the MCF-7 xenografts. Overall, the higher tumour uptake and tumour-to-muscle ratio, alongside the higher expression of OATP1A2, in the MCF-7 xenograft model suggests the potential of E3S to serve as a novel ligand for targeting hormone dependent breast cancers.

Topics: Animals; Breast Neoplasms; Cell Line, Tumor; Estradiol; Estrone; Female; Humans; Ligands; MCF-7 Cells; Mice; Mice, Nude; Organic Cation Transport Proteins

Although grapefruit intake leads to elevated serum estrogen levels when hormones are taken orally, there are no published data on the effect on endogenous levels. We conducted a pilot dietary intervention study among healthy postmenopausal volunteers to test whole grapefruit, 2 juices, and 1 grapefruit soda. Fifty-nine participants were recruited through the Love/Avon Army of Women. The study consisted of a 3-wk run-in, 2 wk of grapefruit intake, and a 1-wk wash-out. Eight fasting blood samples were collected. An additional 5 samples drawn at 1, 2, 4, 8, and 10 hr after grapefruit intake were collected during an acute-phase study for 10 women. Serum assays for estrone (E1), estradiol (E2), estrone-3-sulfate (E1S), dehydroepiandrosterone sulfate, and sex hormone-binding globulin were conducted. Whole grapefruit intake had significant effects on endogenous E1S. Peak effects were seen at 8 hr, increasing by 26% from baseline. No changes in mean E1 or E2 with whole fruit intake were observed. In contrast, fresh juice, bottled juice, and soda intake all had significant lowering effects on E2. The findings suggest an important interaction between grapefruit intake and endogenous estrogen levels. Because endogenous estrogen levels are associated with breast cancer risk, further research is warranted.

Topics: Aged; Beverages; Body Mass Index; Body Weight; Breast Neoplasms; Citrus paradisi; Dehydroepiandrosterone Sulfate; Estradiol; Estrogens; Estrone; Female; Humans; Middle Aged; Pilot Projects; Postmenopause; Risk Factors; Sex Hormone-Binding Globulin; Surveys and Questionnaires

Estrogen synthesis suppression induced by aromatase inhibitors in breast cancer (BC) patients may be affected by single nucleotide polymorphisms (SNPs) of the gene encoding aromatase enzyme, CYP19A1. We assessed the association between plasma estrone sulfate (ES), letrozole treatment, and four SNPs of CYP19A1 gene (rs10046 C>T, rs4646 G>T, rs749292 C>T, rs727479 T>G) which seem to be related to circulating estrogen levels. Patients were enrolled into a prospective, Italian multi-center clinical trial (Gruppo Italiano Mammella, GIM-5) testing the association of CYP19A1 SNPs with the efficacy of letrozole adjuvant therapy, in postmenopausal early BC patients. SNPs were identified from peripheral blood cell DNA. Plasma ES concentrations were evaluated by Radio Immuno Assay. Blood samples were obtained immediately before letrozole therapy (N = 204), at 6-weeks (N = 178), 6 (N = 152) and 12-months (N = 136) during treatment. Medians (IQR) of ES were 160 pg/mL (85-274) at baseline, 35 pg/mL (12-64) at 6-weeks, 29 pg/mL (17-48) at 6 months and 25 pg/mL (8-46) after 12 months treatment. No statistically significant association was evident between polymorphisms and ES circulating levels during letrozole therapy. Letrozole suppression of the aromatase enzyme function is not affected by polymorphisms of CYP19A1 gene in postmenopausal BC patients.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Agents; Aromatase; Aromatase Inhibitors; Breast Neoplasms; Clinical Trials as Topic; Estrone; Female; Genetic Association Studies; Genotype; Humans; Letrozole; Middle Aged; Nitriles; Polymorphism, Single Nucleotide; Postmenopause; Prospective Studies; Triazoles

We have prospectively tested the effects of simvastatin on the pharmacokinetics of anastrozole and on estrogen concentrations in postmenopausal women with hormone receptor-positive breast cancer who were receiving adjuvant anastrozole. Following 14 days of simvastatin, we did not observe a significant change in plasma concentrations of anastrozole or hydroxyanastrozole in nine evaluable women. Likewise, we did not observe any statistically significant change in serum concentrations of either estradiol, which remained in the undetectable range, or estrone sulfate. Simvastatin and anastrozole may be safely co-administered. Pharmacokinetic results suggest that simvastatin is not likely to compromise the activity of anastrozole.

Topics: Aged; Anastrozole; Anticholesteremic Agents; Antineoplastic Agents, Hormonal; Aromatase Inhibitors; Breast Neoplasms; Drug Interactions; Estradiol; Estrone; Female; Humans; Middle Aged; Nitriles; Pilot Projects; Simvastatin; Triazoles

Circulating estrogens are an established risk factor for breast cancer and some data suggest that diet may influence estrogen levels. Therefore, using a subsample (n = 550) of women from a large cohort, we applied reduced rank regression to identify a dietary pattern that was correlated with estradiol and estrone sulfate. We then adapted the pattern to be used with the full cohort (n = 67,802) and prospectively assessed its association with postmenopausal breast cancer. The estrogen food pattern, characterized by higher intakes of red meat, legumes, and pizza, but lower intakes of coffee and whole grains, was modestly but significantly correlated with estradiol (r = 0.14) and estrone sulfate (r = 0.20). During 22 years of follow-up, we ascertained 4,596 incident breast cancer, with 2,938 estrogen receptor-positive tumors and 689 estrogen receptor-negative tumors. However, after adjusting for potential confounders, we did not observe any association with overall estrogen receptor-positive or estrogen receptor-negative breast cancer. In conclusion, diet pattern appeared to only have modest association with estrogens, and was not associated with postmenopausal breast cancer risk. Although these results were null, it should be repeated in other populations as differences in food intake may yield a dietary pattern with stronger association with estrogens.

Topics: Adult; Breast Neoplasms; Cohort Studies; Diet; Estradiol; Estrogens; Estrone; Female; Humans; Middle Aged; Multivariate Analysis; Postmenopause; Receptors, Estrogen; Regression Analysis; Risk Factors; United States

The purpose of this study was to investigate the differential expression and function of organic anion-transporting polypeptides (OATPs) in breast epithelial and breast cancer cells. Estrone-3-sulfate (E3S), a substrate for 7 of 11 OATPs, is a predominant source of tumor estrogen in postmenopausal, hormone-dependent patients with breast cancer. Overexpression of certain OATPs (e.g., OATP1A2) reported in breast tumor tissues compared with surrounding normal tissues could contribute toward two to three times higher tumoral E3S concentration. Little is known about expression and function of other OATP family members among breast epithelial and breast cancer cells. We therefore compared gene and protein expression of seven OATPs (OATP1A2, OATP1B1, OATP1B3, OATP1C1, OATP2B1, OATP3A1, and OATP4A1) in immortalized breast epithelial cells (MCF10A), hormone-dependent breast cancer cells (MCF7), and hormone-independent breast cancer cells (MDA/LCC6-435, MDA-MB-231, and MDA-MB-468) by quantitative polymerase chain reaction and immunoblotting, respectively. Expression of solute carrier superfamily encoding for OATPs (SLCO) 1A2, 1B1, 1B3, 2B1, and 3A1 is exclusive, similar, or significantly higher in cancer cells compared with MCF10A cells. Protein expression of OATPs is found to be either exclusive or higher in cancer cells compared with MCF10A cells. Specificity of OATP-mediated E3S uptake is observed only in cancer cells, with the highest total uptake in MCF7 cells. Transport kinetics of E3S uptake demonstrates transport efficiency that is 10 times greater in the MCF7 cells than in the hormone-independent cells. These data suggest that OATPs could be a novel therapeutic target for hormone-dependent breast cancers, particularly in postmenopausal patients, where the major source of tumor estrogen is E3S.

Topics: Animals; Breast Neoplasms; Cell Line, Tumor; Dogs; Epithelial Cells; Estrogens; Estrone; Female; HEK293 Cells; Humans; Organic Anion Transporters; Postmenopause; RNA, Messenger

To investigate whether suppression of plasma estradiol and estrone sulfate levels by the aromatase inhibitors (AIs) anastrozole and letrozole is related to body mass index (BMI) in postmenopausal women with early estrogen receptor (ER) -positive breast cancer. Recent studies have reported that the AI anastrozole has lower effectiveness than tamoxifen in women with high BMI. This effect with high BMI might hypothetically be a result of reduced inhibition of aromatase and suppression of plasma estrogen levels and might be overcome by the use of an increased dose of anastrozole or, alternatively, the use of a more potent AI such as letrozole.. Plasma estradiol and estrone sulfate levels from a highly sensitive radioimmunoassay were available for 44 postmenopausal patients who received anastrozole (1 mg per day) for 3 months followed by letrozole (2.5 mg per day) for 3 months or the opposite sequence. Correlations between the estrogen suppression by each AI and BMI were assessed.. Baseline values of estradiol and estrone sulfate were significantly correlated with BMI (r = 0.57; P < .001, and r = 0.38; P = .006, respectively). Levels of estrogen in patients receiving treatment were greater at higher levels of BMI with both AIs, but although this was significant with letrozole (r = 0.35; P = .013, and r = 0.30; P = .035 for estradiol and estrone sulfate, respectively), it was not with anastrozole. Suppression of both estrogen types was greater with letrozole across the full range of BMIs in this study.. The suppressed levels of plasma estradiol and estrone sulfate in postmenopausal women with early ER-positive breast cancer treated with the AIs anastrozole and letrozole are related to BMI.

Topics: Aged; Aged, 80 and over; Anastrozole; Antineoplastic Agents, Hormonal; Aromatase Inhibitors; Body Mass Index; Breast Neoplasms; Estrogens; Estrone; Female; Humans; Letrozole; Middle Aged; Neoplasms, Hormone-Dependent; Nitriles; Postmenopause; Triazoles

Levels of endogenous estrogen and SHBG are associated with risk of breast cancer among women who have never used hormone replacement therapy (HRT). We investigated these associations in both never and baseline users of HRT.. A nested case-control study was conducted within the prospective Danish population-based 'Diet, Cancer, and Health' cohort. During follow-up, 348 eligible cases were identified among 20,861 postmenopausal women and matched to 348 controls. Baseline serum samples were analyzed for estradiol, bioavailable estradiol, estrone, estrone sulfate, and SHBG. Conditional logistic regression yielded incidence rate ratios and 95 % confidence intervals for exposures analyzed continuously and categorically in models adjusted for potential confounders.. Modest direct associations were identified between estrogen levels and breast cancer incidence among both never and baseline HRT users. Estrone and estrone sulfate were more consistently associated among both groups than estradiol. No association was found with SHBG.. Despite different hormonal profiles, higher serum estrogen levels were associated with a higher risk of breast cancer among both never and baseline HRT users. More studies are needed to support the findings for HRT users and to further investigate estrogen levels in relation to estrogen receptor-specific breast cancer and other histological and molecular subtypes.

Topics: Breast Neoplasms; Case-Control Studies; Cohort Studies; Estradiol; Estrogen Receptor alpha; Estrogens; Estrone; Female; Hormone Replacement Therapy; Humans; Incidence; Logistic Models; Middle Aged; Prospective Studies; Sex Hormone-Binding Globulin

Estrone-3-sulfate is one of the most abundant estrogen precursors in postmenopausal women. We previously showed that estrone-3-sulfate transporters are present in human breast cancer-derived MCF-7 cells (J. Pharmacol. Exp. Ther. 311 (2004) 1032-1037) and that inhibition of estrone-3-sulfate uptake resulted in the suppression of cell growth (Pharm. Res. 22 (2005) 1634-1641); therefore, estrone-3-sulfate transporter should be a novel target for therapy of hormone-dependent breast cancers. The purpose of the present study is to identify the transporter(s) responsible for the uptake of estrone-3-sulfate in breast cancer cells. We obtained two subclones of MCF-7 cells with different estrone-3-sulfate uptake activities and searched for differentially expressed transporter genes by means of DNA microarray analysis. Among several candidate transporters identified, OATP1B3 was further evaluated, since the uptake characteristics of estrone-3-sulfate by MCF-7 cells seemed consistent with the transport properties of OATP1B3. The contribution of OATP1B3 to estrone-3-sulfate uptake by MCF-7 cells was examined by the relative activity factor (RAF) method, and was calculated to amount to 6%. This result suggests that OATP1B3 is one of the transporters contributing to the supply of the estrogen precursor estrone-3-sulfate to estrogen-dependent breast cancer cells.

Topics: Animals; Biological Transport; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Estrone; Female; Gene Expression Regulation, Neoplastic; Humans; Organic Anion Transporters, Sodium-Independent; Solute Carrier Organic Anion Transporter Family Member 1B3; Xenopus laevis

Previous studies have suggested elevated estrogen production in tumour-bearing breast quadrants as well as in breast cancers versus benign tissue. Using highly sensitive assays, we determined breast cancer tissue estrogen concentrations together with plasma and benign tissue estrogen concentrations in each quadrant obtained from mastectomy specimens (34 postmenopausal and 13 premenopausal women). We detected similar concentrations of each of the three major estrogens estradiol (E(2)), estrone (E(1)) and E(1)S in tumour-bearing versus non-tumour-bearing quadrants. Considering malignant tumours, intratumour E(1) levels were reduced in cancer tissue obtained from pre- as well as postmenopausal women independent of tumour ER status (average ratio E(1) cancer: benign tissue of 0.2 and 0.3, respectively; p<0.001 for both groups), suggesting intratumour aromatization to be of minor importance. The most striking finding was a significant (4.1-8.6-fold) increased E(2) concentration in ER positive tumours versus normal tissue (p<0.05 and <0.001 for pre- and postmenopausal patients, respectively), contrasting low E(2) concentrations in ER- tumours (p<0.01 and <0.001 comparing E(2) levels between ER+ and ER- tumours in pre- and postmenopausals, respectively). A possible explanation to our finding is increased ligand receptor binding capacity for E(2) in receptor positive tumours but alternative factors influencing intratumour estrogen disposition cannot be excluded.

Topics: Adult; Aged; Aged, 80 and over; Breast; Breast Neoplasms; Estradiol; Estrone; Female; Humans; Menopause; Menstrual Cycle; Middle Aged; Neoplasms, Hormone-Dependent; Receptors, Estrogen; Tissue Distribution

The ligand-activated nuclear receptor pregnane X receptor (PXR) is known to play a role in the regulated expression of drug metabolizing enzymes and transporters. Recent studies suggest a potential clinically relevant role of PXR in breast cancer. However, the relevant pathway or target genes of PXR in breast cancer biology and progression have not yet been fully clarified. In this study, we show that mRNA expression of organic anion transporter polypeptide 1A2 (OATP1A2), a transporter capable of mediating the cellular uptake of estrogen metabolites, is nearly 10-fold greater in breast cancer compared with adjacent healthy breast tissues. Immunohistochemistry revealed exclusive expression of OATP1A2 in breast cancer tissue. Interestingly, treatment of breast cancer cells in vitro with the PXR agonist rifampin induced OATP1A2 expression in a time-dependent and concentration-dependent manner. Consistent with its role as a hormone uptake transporter, induction of OATP1A2 was associated with increased uptake of estrone 3-sulfate. The rifampin response was abrogated after small interfering RNA targeting of PXR. We then identified a PXR response element in the human OATP1A2 promoter, located approximately 5.7 kb upstream of the transcription initiation site. The specificity of PXR-OATP1A2 promoter interaction was confirmed using chromatin immunoprecipitation. Importantly, we used a novel potent and specific antagonist of PXR (A-792611) to show the reversal of the rifampin effect on the cellular uptake of E(1)S. These data provide important new insights into the interplay between a xenobiotic nuclear receptor PXR and OATP1A2 that could contribute to the pathogenesis of breast cancer and may also prove to be heretofore unrecognized targets for breast cancer treatment.

Topics: Breast; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Chromatin Immunoprecipitation; Constitutive Androstane Receptor; Dipeptides; Estrogens; Estrone; Female; Humans; Neoplasm Staging; Organic Anion Transporters; Pregnane X Receptor; Promoter Regions, Genetic; Pyridines; Receptors, Cytoplasmic and Nuclear; Receptors, Estrogen; Receptors, Steroid; Rifampin; RNA, Messenger; Transcription Factors

Following the introduction of potent aromatase inhibitors for the treatment of breast cancer patients, highly sensitive methods have become mandatory to evaluate the influence of these drugs on plasma estrogen levels. Commercially available kits for estrogen measurements are not suitable for these kinds of evaluations due to their detection limits that are close to baseline estrogen levels in postmenopausal women. We describe here an optimised radioimmunoassay suitable for the simultaneous measurement of plasma estrone (E1), estradiol (E2) and estrone sulfate (E1S) levels in the ultra-low range. Following incubation with [3H]-labelled estrogens as internal standards, crude estrogen fractions were separated by ether extraction. The E1S fraction was hydrolysed with sulfatase followed by eluation on a Sephadex column. Free estrogens (E1, E2) were separated by chromatography (LH-20). Estrone and E1S (following hydrolysis) were converted into E2, and each estrogen fraction was measured by the same highly sensitive and specific radioimmunoassay using estradiol-6-(O-carboxymethyl)-oximino-2-(2-[125 I]-iodo-histamine) as ligand. Although several purification steps were involved, the internal recovery values for tritiated estrogens were found to be 88%, 90%, and 49% for E1, E2 and E1S, respectively. The intra-assay coefficient of variation was <5% for all recovery measurements. The detection limits were calculated following repeated blank measurements and found to be 1.14 pmol/L for E1, 0.67 pmol/L for E2, and 0.55 pmol/L for E1S, respectively. The intra-assay coefficient of variation (CV) was found to be 3.4% for E1, 5.1% for E2 and 6.1% for E1S, while the inter-assay CV was 13.6%, 7.6% and 7.5% for E1, E2, and E1S, respectively. Considering normal plasma levels for E2 (15 pmol/L), E1 (80 pmol/L) and E1S (400 pmol/L) in postmenopausal women, the method allows theoretically to detect suppression of plasma E2, E1 and E1S levels by 95.5%, 98.6% and 99.9% when starting from average, normal postmenopausal levels. Thus, the method presented here is to our knowledge the currently most sensitive assay available for plasma estrogen measurements in the ultra-low range and, as such, a reliable tool for a proper evaluation of potent aromatase inhibitors and other potential drugs influencing on plasma estrogen levels.

Topics: Aromatase Inhibitors; Blood Chemical Analysis; Breast Neoplasms; Estradiol; Estrone; Humans; Postmenopause; Radioimmunoassay; Sensitivity and Specificity

We screened a series of 17beta-(N-alkylcarbamoyl)-estra-1,3,5(10)trine-3-O-sulfamate derivatives, and describe here a potent and selective steroid sulfatase (STS) inhibitor with antitumor effects in breast cancer models in vitro and in vivo. In biochemical assays using crude enzymes isolated from recombinant Chinese hamster ovary cells expressing human arylsulfatses (ARSs), one of the best compounds, KW-2581, inhibited STS activity with an IC(50) of 4.0 nM, while > 1000-fold higher concentrations were required to inhibit the other ARSs. The failure to stimulate the growth of MCF-7 human breast cancer cells as well as in uteri in ovariectomized rats indicated the lack of estrogenicity of this compound. In MCF-7 cells transfected with the STS gene, termed MCS-2 cells, KW-2581 inhibited the growth of cells stimulated by estrone sulfate (E1S) but also 5-androstene-3beta, 17beta-diol 3-sulfate (ADIOLS) and dehydroepiandrostenedione 3-sulfate. We found that oral administration of KW-2581 inhibited both E1S- and ADIOLS-stimulated growth of MCS-2 cells in a mouse hollow fiber model. In a nitrosomethylurea-induced rat mammary tumor model, KW-2581 induced regression of E1S-stimulated tumor growth as effectively as tamoxifen or another STS inhibitor, 667 Coumate. Dose-response studies in the same rat model demonstrated that more than 90% inhibition of STS activity in tumors was necessary to induce tumor shrinkage. STS activity in tumors has well correlated with that in leukocytes, suggesting that STS activity in leukocytes could be used as an easily detectable pharmacodynamic marker. These findings demonstrate that KW-2581 is a candidate for development as a therapeutic agent for the treatment of hormone receptors-positive breast cancer.

Topics: Administration, Oral; Animals; Breast Neoplasms; Cell Proliferation; Coumarins; Cricetinae; Disease Models, Animal; Enzyme Inhibitors; Estradiol; Estrogen Antagonists; Estrone; Female; Gene Expression Regulation, Enzymologic; Humans; Leukocytes; Methylnitrosourea; Molecular Structure; Rats; Rats, Sprague-Dawley; Receptors, Progesterone; Signal Transduction; Steryl-Sulfatase; Sulfonamides; Sulfonic Acids; Tamoxifen; Tumor Cells, Cultured

The adipocytokine leptin has recently been shown to enhance the expression of aromatase via promoter II and I.3 using an AP-1 motif. Thus, we evaluated the correlation between plasma leptin concentrations and total body aromatization (TBA) as well as plasma levels of estrone (E(1)), estradiol (E(2)) and estrone sulfate (E(1)S) in postmenopausal breast cancer patients. Twenty-two postmenopausal women with metastatic breast cancer, participating in tracer studies for the measurement of total body aromatization (TBA) in vivo, were available. In addition, blood samples for plasma estrogens and leptin measurements were available from another 22 breast cancer patients and 114 healthy postmenopausal women participating in the mammography-screening program. Values for TBA varied from 1.46 to 4.72% while plasma leptin levels ranged from 1.83 to 95.51 ng/ml in the same group of patients. All plasma estrogen levels were in the normal range expected for postmenopausal women. We found a significant correlation between pretreatment leptin levels and TBA (r(s) 0.452, P=0.01). In contrast, basal levels of TBA did not correlate to body mass index (BMI) in the same group of patients. Plasma leptin levels correlated to plasma levels of estradiol (r(s) 0.659, P=0.007), and estrone sulfate (r(s) 0.562, P=0.01) in the group of breast cancer patients (n=44) as well as in the group of healthy postmenopausal women (estradiol, r(s) 0.363, P< or =0.001, estrone sulfate r(s) 0.353, P< or =0.001). In conclusion, we found plasma leptin levels to correlate to TBA in breast cancer patients and to plasma levels of estradiol and estrone sulfate in breast cancer patients as well as in healthy postmenopausal females. These findings suggest that leptin may influence on aromatase activity in vivo, providing a possible link between body weight and plasma estrogen levels as well as breast cancer risk.

Topics: Aged; Androstenedione; Aromatase; Aromatase Inhibitors; Body Mass Index; Breast Neoplasms; Estradiol; Estrone; Female; Humans; Leptin; Middle Aged; Postmenopause

To examine whether the associations of endogenous estrogens and testosterone with breast cancer risk differ between high- and low-risk women, as determined by the Gail model and the Rosner and Colditz model, and by family history of breast cancer.. We conducted a prospective nested case-control study within the Nurses' Health Study. From 1989 or 1990 until June 2000, blood samples were collected, 418 breast cancer patient cases were identified, and two controls (total n = 817) were matched to each case. We classified women as high or low risk based on their family history of breast cancer, their 5-year Gail risk score, and their 5-year Rosner and Colditz risk score. Multivariate relative risks (RR) and 95% CI were calculated by unconditional logistic regression, adjusting for matching and breast cancer risk factors.. Estrone sulfate was statistically significantly associated with breast cancer risk among women with low (< 1.66%) and high (> or = 2.52%; 75th percentile) Gail predicted risk (fourth v first quartile RR = 3.6; 95% CI, 1.9 to 7.0; RR = 2.5; 95% CI, 1.2 to 5.1, respectively). Testosterone results were similar across strata of predicted risk, with two times the risk in the fourth (v first) quartile. Estradiol appeared more strongly associated with breast cancer in women with higher predicted risk (RR = 4.5; 95% CI, 2.1 to 9.5) compared with women with lower risk (RR = 2.1; 95% CI, 1.2 to 3.6), but differences were not statistically significant. Results were similar across predicted Rosner and Colditz risk scores.. These data suggest that higher levels of endogenous estrogens and testosterone are associated with increased breast cancer risk, regardless of predicted risk or family history of breast cancer.

Topics: Adult; Breast Neoplasms; Case-Control Studies; Estradiol; Estrone; Female; Genetic Predisposition to Disease; Humans; Middle Aged; Pedigree; Prognosis; Prospective Studies; Risk Factors; Testosterone

We assessed the relationship between serum concentrations of estrogens, androgens, and sex hormone-binding globulin and risk of breast cancer among postmenopausal women. Study participants provided serum prior to breast biopsy or mastectomy in 3 hospitals in Grand Rapids, Michigan between 1977 and 1987. A total of 179 subjects with localized breast cancer were compared to 152 subjects with nonproliferative breast changes that have not been associated with elevated breast cancer risk. Increasing serum concentrations of estrone and estrone sulfate were associated with increases in breast cancer risk; the odds ratios (ORs) in the fourth quartiles compared to the first were 2.3 (95% confidence interval (CI) 1.1-4.6) for both (p-trend = 0.02 and 0.03, respectively). Estradiol and bioavailable estradiol concentrations were associated with nonstatistically significant increases in risk. Androstenediol levels were associated with risk (p-trend = 0.01); the OR in the fourth compared to the first quartile was 2.2 (95% CI 1.0-4.6). Testosterone, dehydroepiandrosterone and androstenedione levels were not associated with increased risk. Sex hormone-binding globulin was associated with a nonsignificant decrease in risk. Associations with estrone and estrone sulfate persisted after adjustment for androstenediol (ORs for fourth compared to first quartiles were 2.0 (95% CI 0.9-4.5) and 2.2 (95% CI 1.0-4.6), respectively (p-trend = 0.16 for both). The association with androstenediol was attenuated after adjustment for estrone (OR for fourth compared to first quartile was 1.6 (95% CI 0.7-3.6); p-trend = 0.13). Higher serum concentrations of estrogens were associated with increased breast cancer risk in postmenopausal women. Androgen levels were not independently associated with substantially increased risk.

Topics: Aged; Androgens; Androstenediol; Breast Neoplasms; Dehydroepiandrosterone; Estrogens; Estrone; Female; Humans; Middle Aged; Odds Ratio; Postmenopause; Retrospective Studies; Risk Assessment; Risk Factors; Sex Hormone-Binding Globulin; Testosterone

While growth factors and hormones are known to influence aromatase expression in experimental systems, little is know about potential factors influencing peripheral aromatization in postmenopausal women. The fact that peripheral aromatase activity is higher in old compared to young women and the finding of relatively high tissue estradiol (E2) concentrations after the menopause suggests peripheral aromatization could be influenced by estrogen concentration. To test this hypothesis, we determined plasma hormone levels (n=9) and in vivo aromatization (n=3) in postmenopausal women suffering from advanced breast cancer before and during treatment (4 weeks) with diethylstilbestrol (DES) 5mg three times daily. Plasma levels of cortisol (C), corticosteroid-binding globulin (CBG), and sex hormone binding globulin (SHBG) were significantly increased in all patients (P<0.05 for all). While we found no change in total body aromatization and plasma estrone (E(1)) levels, estradiol (E(2)) and estrone sulfate (E(1)S) were suppressed by a mean of 48.8 and 68.2%, respectively (P=0.043 and 0.008). Surprisingly, plasma levels of androstenedione (A), testosterone (T), dehydroepiandrosterone (DHEA) and its sulfate (DHEAS) were also suppressed by a mean in the range of 32.1 to 52.6% (P<0.05 for all androgens). In contrast, no change in plasma progesterone or 17alpha-hydroxyprogesterone was found. Thus, one possible explanation to our findings could be that DES administered in high doses reduces 17,20-lyase activity in the adrenal gland.

Topics: Aged; Aged, 80 and over; Androgens; Androstenedione; Breast Neoplasms; Diethylstilbestrol; Drug Administration Schedule; Estradiol; Estrogens; Estrogens, Non-Steroidal; Estrone; Female; Humans; Hydrocortisone; Middle Aged; Postmenopause; Sex Hormone-Binding Globulin

The aim of the study is to suppress the progress of estrogen-dependent breast cancer by inhibiting the membrane transporter, which mediates the internalization of estrone-3-sulfate as estrogen precursor in the cancer cells.. The uptake of estrone-3-sulfate by estrogen-dependent breast cancer MCF-7 cells was measured, and inhibitory study using various organic anions on estrone-3-sulfate uptake by MCF-7 cells was conducted. The effects of the inhibitor on the transcription of reporter gene and cell proliferation induced by estrone-3-sulfate were examined.. The uptake of estrone-3-sulfate by MCF-7 cells was saturable with Km value of 2.32 microM. The uptake was Na+-independent and was inhibited by several anionic compounds such as bromosulfophthalein. Bromosulfophthalein also significantly inhibited the transcription of reporter gene via estrogen response element and cell proliferation induced by estrone-3-sulfate. However, the transcriptional activation or cell proliferation induced by estrone was not inhibited by bromosulfophthalein. Reverse transcription-polymerase chain reaction analysis revealed the expression of mRNA of organic anion transporting polypeptide (OATP)-D and OATP-E as possible candidates to transport estrone-3-sulfate.. The uptake of estrone-3-sulfate is mediated by Na+-independent transporter(s). Inhibitor of estrone-3-sulfate transporter suppressed the transcription and cell proliferation induced by estrone-3-sulfate in MCF-7 cells. The results provide the basis of a novel strategy for breast cancer treatment by focusing on the transporter responsible for the uptake of estrone-3-sulfate.

Topics: Alkaline Phosphatase; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Drug; Estrogens; Estrone; Female; Humans; Indicators and Reagents; Membrane Transport Proteins; Sulfobromophthalein; Transcriptional Activation

A number of 2-phenylindole sulfamates with lipophilic side chains in 1- or 5-position of the indole were synthesized and evaluated as steroid sulfatase (estrone sulfatase) inhibitors. Most of the new sulfamates inhibited the enzymatic hydrolysis of estrone sulfate in MDA-MB 231 breast cancer cells with IC(50) values between 2 nM and 1 microM. A favorable position for a long side chain is the nitrogen of a carbamoyl group at C-5 of the indole when the phenyl ring carries the sulfamate function. These derivatives inhibit gene activation in estrogen receptor (ER)-positive MCF-7 breast cancer cells in submicromolar concentrations and reduce cell proliferation with IC(50) values of ca. 1 microM. All of the potent inhibitors were devoid of estrogenic activity and have the potential for in vivo application as steroid sulfatase inhibitors.

Topics: Antineoplastic Agents; Breast Neoplasms; Cell Division; Enzyme Inhibitors; Estrone; Female; Gene Expression Regulation, Neoplastic; Humans; Hydrolysis; Hydrophobic and Hydrophilic Interactions; Inhibitory Concentration 50; Receptors, Estrogen; Steryl-Sulfatase; Structure-Activity Relationship; Sulfonic Acids; Transcriptional Activation

Light exposure during night work suppresses melatonin production, and night work has been associated with an increased cancer risk. There is little information, however, about the interrelationships of night work, urinary melatonin levels, and levels of plasma steroid hormones in women.. We examined the reproducibility of morning urinary measurements of 6-sulfatoxymelatonin over a 3-year period in 80 premenopausal women. We assessed correlations between average urinary melatonin and plasma steroid hormone levels and evaluated potential associations between night work and hormone levels, using current and long-term shift work information from two large, prospective cohorts, the Nurses' Health Study cohorts.. The intraclass correlation for creatinine-adjusted 6-sulfatoxymelatonin was 0.72 (95% confidence interval, 0.65, 0.82). We found significantly increased levels of estradiol after longer durations of night work (geometric mean levels of estradiol, 8.8 pg/mL for women who never worked night shifts versus 10.1 pg/mL for women who worked 15 or more years of night shifts; P for trend = 0.03). We observed a significant inverse association between increasing number of nights worked within the 2 weeks preceding urine collection and urinary melatonin levels (r = -0.30, P = 0.008), but no association of recent night work with estradiol (r = 0.10, P = 0.41).. A single morning urinary melatonin measurement is a reasonable marker for long-term melatonin levels among premenopausal women. Women who work on rotating night shifts seem to experience changes in hormone levels that may be associated with the increased cancer risk observed among night-shift workers.

Topics: Adult; Androstenedione; Androstenols; Biological Availability; Biomarkers; Body Mass Index; Breast Neoplasms; Cohort Studies; Creatinine; Dehydroepiandrosterone; Estradiol; Estrone; Female; Hormones; Humans; Light; Melatonin; Middle Aged; Nurses; Prolactin; Reproducibility of Results; Risk Factors; Specimen Handling; Steroids; Work Schedule Tolerance

Although circulating estrone-3-sulfate is a major precursor of biologically active estrogen, permeation across the plasma membrane is unlikely to occur by diffusion because of the high hydrophilicity of the molecule. The object of this study was to clarify the involvement of specific transporter(s) in the supply of estrone-3-sulfate to human breast cancer-derived T-47D cells, which grow in an estrogen-dependent manner. The proliferation of T-47D cells was increased by the addition of estrone-3-sulfate, or estradiol, to the cultivation medium. The initial uptake rate of estrone-3-sulfate kinetically exhibited a single saturable component, with Km and Vmax values of 7.6 microM and 172 pmol/mg of protein/min, respectively. The replacement of extracellular Na+ with Li+, K+, or N-methylglucamine+ had no effect on the uptake of [3H]estrone-3-sulfate. The uptake was strongly inhibited by sulfate conjugates of steroid hormones, but not by estradiol-17beta-glucuronide. Taurocholate and sulfobromophthalein inhibited the uptake, whereas other tested anionic and cationic compounds did not. The expression of organic anion transporting polypeptides, OATP-D and OATP-E, which are candidate transporters of estrone-3-sulfate, was detected by reverse transcription-polymerase chain reaction analysis, although their actual involvement in the uptake of estrogen remains to be clarified. In conclusion, the uptake of estrone-3-sulfate by T-47D cells was mediated by a carrier-mediated transport mechanism, suggesting that the estrogen precursor is actively imported by estrogen-dependent breast cancer cells.

Topics: Breast Neoplasms; Cations; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Drug; Estradiol; Estrone; Female; Hormones; Humans; Kinetics; Neoplasm Proteins; Organic Anion Transporters; Reverse Transcriptase Polymerase Chain Reaction; Stimulation, Chemical

Levels of endogenous hormones have been associated with the risk of breast cancer among postmenopausal women. Little research, however, has investigated the association between hormone levels and tumor receptor status or invasive versus in situ tumor status. Nor has the relation between breast cancer risk and postmenopausal progesterone levels been investigated. We prospectively investigated these relations in a case-control study nested within the Nurses' Health Study.. Blood samples were prospectively collected during 1989 and 1990. Among eligible postmenopausal women, 322 cases of breast cancer (264 invasive, 41 in situ, 153 estrogen receptor [ER]-positive and progesterone receptor [PR]-positive [ER+/PR+], and 39 ER-negative and PR-negative [ER-/PR-] disease) were reported through June 30, 1998. For each case subject, two control subjects (n = 643) were matched on age and blood collection (by month and time of day). Endogenous hormone levels were measured in blood plasma. We used conditional and unconditional logistic regression analyses to assess associations and to control for established breast cancer risk factors.. We observed a statistically significant direct association between breast cancer risk and the level of both estrogens and androgens, but we did not find any (by year) statistically significant associations between this risk and the level of progesterone or sex hormone binding globulin. When we restricted the analysis to case subjects with ER+/PR+ tumors and compared the highest with the lowest fourths of plasma hormone concentration, we observed an increased risk of breast cancer associated with estradiol (relative risk [RR] = 3.3, 95% confidence interval [CI] = 2.0 to 5.4), testosterone (RR = 2.0, 95% CI = 1.2 to 3.4), androstenedione (RR = 2.5, 95% CI = 1.4 to 4.3), and dehydroepiandrosterone sulfate (RR = 2.3, 95% CI = 1.3 to 4.1). In addition, all hormones tended to be associated most strongly with in situ disease.. Circulating levels of sex steroid hormones may be most strongly associated with risk of ER+/PR+ breast tumors.

Topics: Aged; Androgens; Androstenedione; Breast Neoplasms; Case-Control Studies; Confidence Intervals; Dehydroepiandrosterone; Estradiol; Estrogens; Estrone; Female; Humans; Middle Aged; Postmenopause; Progesterone; Receptors, Estrogen; Receptors, Progesterone; Risk Assessment; Risk Factors; Testosterone

Breast cancer resistance protein (BCRP), an ATP-binding cassette transporter, confers resistance to a series of anticancer reagents such as mitoxantrone, 7-ethyl-10-hydroxycamptothecin, and topotecan. We reported previously that estrone and 17beta-estradiol reverse BCRP-mediated multidrug resistance. In the present study, we demonstrate that BCRP exports estrogen metabolites. First, we generated BCRP-transduced LLC-PK1 (LLC/BCRP) cells, in which exogenous BCRP is expressed in the apical membrane, and investigated transcellular transport of 3H-labeled compounds using cells plated on microporous filter membranes. The basal-to-apical transport (excretion) of mitoxantrone, estrone, and 17beta-estradiol was greater in LLC/BCRP cells than in LLC-PK1 cells. Thin-layer chromatography of transported steroids revealed that the transport of estrone and 17beta-estradiol was independent of BCRP expression. Alternatively, increased excretion of estrone sulfate and 17beta-estradiol sulfate was observed in LLC/BCRP cells. BCRP inhibitors completely inhibited the increased excretion of sulfated estrogens across the apical membrane. Conversion of estrogens into their sulfate conjugates was similar between LLC/BCRP and LLC-PK1 cells, suggesting that the increased excretion of estrogen sulfates was attributable to BCRP-mediated transport. Next, the uptake of 3H-labeled compounds in membrane vesicles from BCRP-transduced K562 (K562/BCRP) cells was investigated. 3H-labeled estrone sulfate, but not 3H-labeled estrone or 17beta-estradiol, was taken up by membrane vesicles from K562/BCRP cells, and this was ATP-dependent. Additionally, BCRP inhibitors suppressed the transport of estrone sulfate in membrane vesicles from K562/BCRP cells. These results suggest that BCRP does not transport either free estrone or 17beta-estradiol but exports sulfate conjugates of these estrogens.

Topics: Animals; ATP Binding Cassette Transporter, Subfamily G, Member 2; ATP-Binding Cassette Transporters; Biological Transport; Breast Neoplasms; Cell Line; Dose-Response Relationship, Drug; Drug Resistance, Neoplasm; Estrogens; Estrogens, Conjugated (USP); Estrone; LLC-PK1 Cells; Models, Molecular; Neoplasm Proteins; Sulfates; Swine

The presence of estrone sulfatase in breast tumors and the high levels of circulating estrone sulfate may contribute the major portion of estrogen synthesized locally in breast tissues through conversion of estrone sulfate to estrone by the enzyme. Using inhibitors of estrone sulfatase for the treatment of estrogen-dependent (estrogen receptor positive, ER(+)) breast cancer could be a very effective therapeutic strategy for the treatment of estrogen-dependent breast tumors in postmenopausal women. Therefore, we designed and synthesized several steroidal 2',3'-oxathiazines that inhibit estrone sulfatase and have greatly reduced estrogenic side effects. Our in vitro studies indicate that the oxathiazine compounds have inhibitory activity on estrone sulfatase in MCF-7 human breast cancer cells. These estrone sulfatase inhibitors (ESIs) also inhibit the growth of MCF-7 cells induced by estrone sulfate. In addition, our in vivo experiments demonstrate that our ESIs have moderate antitumor activity against MCF-7 breast cancer xenografts in Balb/c athymic nude mice. The synthesis and biological activity of a number of these unique steroidal ESIs are described.

Topics: Animals; Antineoplastic Agents; Breast Neoplasms; Cell Division; Drug Evaluation, Preclinical; Enzyme Inhibitors; Estrone; Female; Humans; Mice; Mice, Nude; Neoplasms, Experimental; Steroids; Structure-Activity Relationship; Sulfatases; Thiazines; Transplantation, Heterologous; Tumor Cells, Cultured

Estrogens regulate the growth and differentiation of mammary cells and play an important role in the development of breast cancer. High circulating levels of estrogens are associated with increased risk of breast cancer in Caucasian women. Because Asian women have low estrogens in the circulation compared with their Caucasian counterparts, the effect of estrogens on breast cancer risk in populations with low circulating estrogens remains to be elucidated. We conducted a population-based case-control study in China to evaluate the association of sex steroid hormones with breast cancer risk in Chinese women. Our study included 300 incident cases with primary breast cancer and 300 age- and menopausal status-matched healthy controls randomly selected from the general population in Shanghai. Fasting blood samples were collected from cases prior to any treatment and from their matched controls. Commercial immunoassays were used to measure plasma concentrations of estradiol, estrone, estrone sulfate, testosterone, progesterone, dehydroepiandrosteindian sulfate (DHEA-S) and steroid hormone-binding globulin (SHBG). Conditional logistic regression analysis was performed to examine the association between steroid hormones and breast cancer risk. The results showed that breast cancer risk was elevated with increasing levels of estrone and testosterone (p for trend < 0.05) but not with DHEA-S, estradiol, estrone sulfate, progesterone or SHBG. The estimated relative risks between upper and lower tertiles were 2.07 (95% confidence interval [CI] 0.97-4.41) for estrone in postmenopausal women, 2.01 (95% CI 0.96-4.21) for testosterone in premenopausal women, and 2.40 (95% CI 1.11-5.21) for testosterone in postmenopausal women, after adjusting for age at first live birth, waist-to-hip ratio, total calorie intake, a history of fibroadenoma, a family history of breast cancer and SHBG. These results, in general, are consistent with the findings in Caucasian women and indicate that high sex steroid hormones in the circulation, both androgen and estrogen, are associated with increased risk of breast cancer even in populations with relatively low sex hormones.

Topics: Adult; Breast Neoplasms; Case-Control Studies; China; Dehydroepiandrosterone Sulfate; Estradiol; Estrone; Female; Humans; Logistic Models; Middle Aged; Postmenopause; Premenopause; Progesterone; Radioimmunoassay; Risk; Sex Hormone-Binding Globulin; Steroids; Surveys and Questionnaires; Testosterone

Circulating hormones and local biotransformation of steroid precursors are both sources of estrogen in human mammary tissue. Estrone-3-sulfate (E(1)S) is an important estrogenic form in premenopausal women, and dehydroepiandrosterone sulfate (DHEAS) constitutes a major adrenal precursor. Membrane transport systems that govern delivery of these anionic steroid conjugates to the mammary gland were investigated. RNA was screened by RT-PCR and Northern blotting for expression of organic anion transporting polypeptide (OATP) (solute carrier family 21A) and organic anion transporter (OAT) (solute carrier family 22A) gene families. OATP-B (SLC21A9) was the major carrier expressed; OATP-D (SLC21A11) and OATP-E (SLC21A12) were less abundant. In normal sections, OATP-B immunolocalized to the myoepithelium that surrounds the ductal epithelial cells. In invasive carcinoma, ductal epithelial cells were positive. OATP-B was characterized in stable transfected Chinese hamster ovary cells. E(1)S affinity constant (K(m)) [K(m) = 5 micro mol/liter, maximum velocity (V(max)) V(max) = 777 pmol/mg.min] and DHEAS (K(m) = 9 micro mol/liter, V(max) = 85 pmol/mg.min) were substrates. The prostaglandins (PG) A(1) and PGA(2) stimulated uptake of E(1)S and DHEAS by increasing V(max) 2-fold but not changing K(m). The effect of PGA was selectively blocked by the lipophilic thiol reagent N-ethylmaleimide but not by the hydrophilic acetamido-4'(iodoacetyl)aminostilbene-2,2'-disulfonic acid, suggesting an interaction between the electrophilic cyclopentenone ring and specific cysteine residues of OATP-B.

Topics: Algorithms; Animals; Biological Transport, Active; Blotting, Northern; Breast; Breast Neoplasms; CHO Cells; Cricetinae; Dehydroepiandrosterone Sulfate; Epithelium; Estrone; Female; Fluorescent Antibody Technique; Humans; Immunohistochemistry; Kinetics; Organic Anion Transporters; Reverse Transcriptase Polymerase Chain Reaction; Steroids; Sulfates; Transfection

Compounds which interfere with steroid sulfatase (STS) are expected as important novel therapeutic drugs for postmenopausal breast tumor. Therefore, a number of strategies have been adopted to design and synthesize potent, nonestrogenic STS inhibitors. We chose biphenyl as a scaffold for STS inhibitors and synthesized some biphenyl-4-O-sulfamate derivatives (29-43). Their inhibitory activity on STS and estrogenicity were evaluated. Substitution of electron-withdrawing groups (e.g., cyano, nitro) at the 2'- or 4'-position of biphenyl-4-O-sulfamate remarkably increased STS-inhibitory activity. Especially, 2',4'-dicyanobiphenyl-4-O-sulfamate (35, TZS-8478) showed very potent STS-inhibitory activity in vitro. The administration of TZS-8478 (0.5 mg/kg per day, p.o., for 5 days) completely inhibited rat liver and uterine STS similarly to EMATE (1). Furthermore, TZS-8478 (10 mg/kg per day, p.o., for 5 days) had no stimulative effect on uterine growth in ovariectomized rats, and its desulfamoylated compound (20) was little bound to the human estrogen receptor alpha. The identification of a potent steroid sulfatase inhibitor without estrogenicity, such as TZS-8478, should be of considerable value in evaluating the potential of steroid sulfatase inhibition for breast tumor therapy.

Topics: Animals; Biphenyl Compounds; Breast Neoplasms; Cell Line, Tumor; Enzyme Inhibitors; Estradiol; Estrogen Receptor alpha; Estrone; Female; Humans; Liver; Organ Size; Rats; Rats, Sprague-Dawley; Receptors, Estrogen; Steryl-Sulfatase; Structure-Activity Relationship; Sulfonic Acids; Uterus

Estrogens play important roles in the development of breast cancer. Inflammatory cytokines such as interleukin-6 (IL-6) and interleukin-1 beta (IL-1 beta) exist at high concentrations in breast cancer tissue. Although these cytokines are thought to exert some effect on cancer growth, their precise mechanism is still unclear. In the present study, we investigated the effects of inflammatory cytokines on aromatase (Arom) and steroid sulfatase (STS), which are estrogen-producing enzymes, and cell proliferation using human breast cancer cell lines (SK-BR-3, MCF-7). IL-6 and IL-1 beta stimulated the activity of Arom and STS. Estrone sulfate (E1-S) had a stimulus effect on cell proliferation of MCF-7. Although IL-6 did not show significant effect on cell proliferation, cell proliferation was significantly increased when IL-6 and E1-S were simultaneously added to the incubation medium. This cell proliferative effect was apparently stronger than the addition of E1-S alone. Addition of IL-1 beta in the presence of E1-S also significantly enhanced cell proliferation though IL-1 beta alone did not show any effect. These results led us to the hypothesis that inflammatory cytokines such as IL-6 and IL-1 beta regulate proliferation of breast cancer cells through estrogen production by steroid-catalyzing enzymes in the tissue.

Topics: Aromatase; Arylsulfatases; Breast Neoplasms; Cell Division; Estrogens; Estrone; Female; Humans; Interleukin 1 Receptor Antagonist Protein; Interleukin-1; Interleukin-6; Sialoglycoproteins; Steryl-Sulfatase; Sulfonic Acids; Tumor Cells, Cultured

The enzyme steryl sulfatase may help support the growth of hormone-dependent tumors, including prostate cancers, by facilitating the conversion of circulating precursor steroids to active hormones. We sought to determine the presence of steryl sulfatase activity in the androgen-dependent human prostate cancer cell line LNCaP, and to determine if this activity was inhibited by known steryl sulfatase inhibitors. Intact LNCaP cultures had steryl sulfatase activity, as determined by conversion of [3H]estrone sulfate (E(1)S) to unconjugated steroids. The level of steryl sulfatase activity was relatively low (4.6 pmol/18 h/million cells) compared to MDA-MB-231 breast cancer cells (284.0 pmol/18 h/million cells). The observed activity in both cell lines was blocked by addition of 1 microM estrone sulfamate (EMATE), an active-site-directed, steroidal inhibitor of steryl sulfatase. Steryl sulfatase activity was also inhibited by Danazol, and by (p-O-sulfamoyl)-tetradecanoyl tyramine (C2-14), a non-steroidal inhibitor. Microsomes prepared from LNCaP cultures also showed steryl sulfatase activity, as determined by hydrolysis of [3H]E(1)S and [3H]dehydroepiandrosterone sulfate (DHEAS) to unconjugated forms. LNCaP and MDA-MB-231 microsomes both hydrolyzed E(1)S about two times faster than DHEAS. Hydrolysis of E(1)S in LNCaP and MDA-MB-231 microsomes was blocked by steryl sulfatase inhibitors with the following relative potencies: EMATE>C2-14>Danazol. These data demonstrate that LNCaP prostate cancer cells contain a steryl sulfatase with properties similar to that found in human breast cancer cells, and that the activity of this enzyme can be blocked by known steryl sulfatase inhibitors. Steryl sulfatase inhibitors may be useful as an adjuvant to androgen deprivation therapy for prostate cancer.

Topics: Arylsulfatases; Breast Neoplasms; Danazol; Dehydroepiandrosterone Sulfate; Enzyme Inhibitors; Estrone; Female; Humans; Kinetics; Male; Microsomes; Prostatic Neoplasms; Steryl-Sulfatase; Sulfonamides; Tumor Cells, Cultured; Tyramine

Steroid sulfatase (STS) is a new target for the endocrine therapy of breast cancer. To ascertain some of the requirements for inhibition of estrone sulfatase activity, a number of novel analogues of estrone 3-O-sulfate possessing sulfate surrogates were synthesized and evaluated as inhibitors of estrone sulfatase (STS) in comparison to a lead inhibitor, estrone-3-O-methylthiophosphonate (E1-3-MTP). Using a selective enzyme digestion, one of the diastereoisomers of this compound, (R(p))-E1-3-MTP, could be prepared and evaluated. From structure-activity studies, we show that chirality at the phosphorus atom, hydrophobicity, basicity, size, and charge all influence the ability of a compound to inhibit estrone sulfatase activity. Of these, hydrophobicity seems to be the most important since simple, active nonsteroidal inhibitors, based on 5,6,7,8-tetrahydronaphth-2-ol (THN), can be prepared, provided that they are lipophilic enough to partition into a nonpolar environment. Also, a negatively charged group is favorable for optimal binding, although it appears that the presence of a potentially cleavable group can compensate for lack of charge in certain cases. A homology model of STS has been constructed from the STS sequence, and molecular docking studies of inhibitors have been performed to broaden the understanding of enzyme/inhibitor interactions. This model clearly shows the positions of the key amino acid residues His136, His290, Lys134, and Lys368 in the putative catalytic region of the formylglycine at position 75, with residues Asp35, Asp36, Asp342, and Gln343 as ligands in the coordination sphere of the magnesium ion. Docking studies using the substrate and estrone-3-sulfate mimics that are active inhibitors indicate they are positioned in the area of proposed catalysis, confirming the predictive power of the model.

Topics: Animals; Binding Sites; Breast Neoplasms; Crotalid Venoms; Drug Screening Assays, Antitumor; Enzyme Inhibitors; Estrone; Humans; Models, Chemical; Models, Molecular; Molecular Mimicry; Organophosphonates; Sequence Homology, Amino Acid; Stereoisomerism; Structure-Activity Relationship; Sulfatases; Tetrahydronaphthalenes; Tumor Cells, Cultured

Women with gross cystic breast disease may have an increased risk of breast cancer. In this study the ability of breast cyst fluid (BCF), obtained from British or Hungarian women, to modulate oestrone sulphate (E1S) formation or hydrolysis, has been examined. For this, oestrogen receptor-positive (ER+) MCF-7 or MDA-MB-231 (ER-) breast cancer cells were employed. The formation and hydrolysis of E1S was measured using radiometric techniques. BCF from British and Hungarian women mainly inhibited E1S hydrolysis in MCF-7 cells while stimulating hydrolysis in MDA-MB-231 cells. The extent of inhibition or stimulation of E1S hydrolysis in these cells was related to the Na+/K+ ratio of the BCF. There was a significant inverse relationship between the extent to which BCF samples inhibited hydrolysis in MCF-7 cells and stimulated it in MDA-MB-231 cells. BCF stimulated E1S formation in MCF-7 cells while inhibiting formation in MDA-MB-231 cells. No difference in the ability of BCF from British or Hungarian women to inhibit or stimulate E1S hydrolysis was detected in ER+ or ER- breast cancer cells. In contrast, BCF from British women stimulated E1S formation in ER+ cells (median 82%) to a significantly greater extent (P < 0.01) than BCF from Hungarian women (median 33%). The role that E1S has in breast cancer development remains unclear. The greater stimulation of E1S formation by BCF from British women, who have a higher risk of breast cancer than Hungarian women, suggests that it may act as a storage form of oestrogen within cells that can be activated by oestrone sulphatase.

Topics: Breast Neoplasms; Cyst Fluid; Estrogens; Estrone; Female; Fibrocystic Breast Disease; Humans; Hungary; Hydrolysis; United Kingdom

Estrogen deprivation is an effective approach for treatment of hormone sensitive breast cancer. While much is known about plasma estrogen levels with respect to castration in premenopausal women and use of aromatase inhibitors in postmenopausal women, currently there is increasing interest in intra-tumour estrogen production. However, knowledge about alterations in intra-tumour estrogen levels is limited, mainly due to methodological problems with measurements of estrogen fractions in tissue samples. Here we describe a new method for simultaneous measurement of the three main estrogen fractions, estrone (E(1)), estradiol (E(2)) and estrone sulphate (E(1)S) in breast tumour tissue. Following incubation with -labelled estrogen standards, crude fractions were separated by ether extraction. The E(1)S fraction was hydrolysed with sulphatase followed by eluation on a Sephadex column. High pressure liquid chromatography (HPLC) was used to purify the individual estrogen fractions prior to RIA analysis. Estrone and E(1)S were converted into E(2), and all three estrogen fractions were finally measured by the same highly sensitive and specific radioimmunoassay using estradiol-6-(O-carboxymethyl)-oximino-2-(2--iodo-histamine) as a ligand. Although several purification steps were used, the internal recovery values for tritiated estrogens were found to be 25-50% for E(1) and E(2) and 15-30% for E(1)S. The detection limit of this method was 4.3 fmol/g tissue for E(2), 19.8 fmol/g tissue for E(1) and 11.9 fmol/g E(1)S, respectively. Using tissue from locally advanced breast cancers (n = 14), we found median levels of E(1), E(2) and E(1)S to be 283.8 fmol/g tissue (range 19.8-547.5), 554.1 fmol/g (9.5-3024.2) and 209.4 fmol/g (11.9-753.4), respectively. The method described here is a promising tool to study intra-tumour estrogen fractions in breast tissue biopsies.

Topics: Anastrozole; Antineoplastic Agents, Hormonal; Breast Neoplasms; Chromatography, High Pressure Liquid; Estradiol; Estrone; Female; Humans; Nitriles; Postmenopause; Radioimmunoassay; Reproducibility of Results; Sensitivity and Specificity; Triazoles

The CYP19 gene codes for aromatase, a key steroidogenic enzyme involved in the conversion of androgens to estrogens. A tetranucleotide (TTTA) repeat polymorphism is present in intron 4 of CYP19; 2 out of 4 breast cancer case-control studies have reported a greater frequency of 2 specific alleles among affected women. We evaluated associations between CYP19 repeat alleles and breast cancer risk in a case-control study nested within the Nurses' Health Study cohort (incident cases: n=462; controls: n=618). We observed seven different CYP19 alleles (TTTA(7-13)). Compared to controls, cases had a statistically significant greater frequency of the 10 (TTTA)(10) repeat allele (10 allele: 2.3% vs. 0.7%, p = 0.005) and a nonsignificant increase in the frequency of the 12 (TTTA)(12) allele (12 allele: 3.1% vs. 2.1%, p = 0.11). A higher frequency of the 10 allele was observed in more advanced cancer cases defined as four or more involved nodes or distant metastasis [4+ nodes: 5/36 (13.9%) vs. 0-3 nodes: 13/330 (3.9%), p = 0.02]. Among controls, we found women with the 7 repeat allele to have decreased levels of estrone sulfate (-16.4%, p = 0.02), estrone (-6.1%, p = 0.22) and estradiol (-9.9%, p = 0.10), and a lower estrone/androstenedione ratio (E1/A) (-10.5%, p = 0.08) compared to non-carriers. A higher E1/A ratio and elevated estrogen levels were observed among carriers of the 8 repeat allele; E1/A ratio (+21.0%, p = 0.003), estrone (+7.5%, p = 0.16) and estradiol (+10.8%, p = 0.08). However, we observed no evidence of an association between these alleles and breast cancer risk. We were unable to make inferences regarding the effect of the 10 allele on hormone levels due to the small number of allele carriers in the subgroup with hormone levels. As this repeat polymorphism is not close to the splice sites in intron 4, linkage disequilibrium with other functional polymorphisms in CYP19 may explain the findings of an increased association between breast cancer and the 10 allele variant of CYP19. We did not detect any sequence variants in the regulatory region or in the adipose-specific exon I.4. The lack of an established effect on CYP19 function associated with the 10 allele means that these findings should be interpreted with caution.

Topics: Alleles; Aromatase; Breast Neoplasms; Case-Control Studies; Estradiol; Estrone; Female; Genotype; Humans; Introns; Linkage Disequilibrium; Menopause; Microsatellite Repeats; Models, Statistical; Polymorphism, Genetic; Risk; Sequence Analysis, DNA; Transcription, Genetic

Substantial differences in plasma oestrogen disposition have been reported between Japanese and Caucasian women, but there are currently few data available on the relative endocrinological effects of aromatase inhibitors in these two groups. Hence, the effects of the nonsteroidal aromatase inhibitor anastrozole on serum oestrogen concentrations were compared in 24 healthy postmenopausal Japanese women and 24 healthy postmenopausal Caucasian women.. Anastrozole, 1 mg/day, was given once daily for 16 days. Serum oestradiol and oestrone sulphate levels were measured on three consecutive days beginning 2 days before the first dose, and on a further three consecutive days beginning on the penultimate day of dosing. Trough concentrations of anastrozole (measured 24 h after dosing) were also determined during the same periods.. There were no substantial differences in plasma oestrogen concentrations between the Japanese and Caucasian women at baseline. On average, anastrozole suppressed serum oestradiol and oestrone sulphate levels by approximately 87% and 93%, respectively, for both Japanese and Caucasian women, and minimum plasma anastrozole concentrations at steady-state (anastrozole C(min)) were also similar in both groups. Statistical analysis of serum oestradiol and serum oestrone sulphate levels, and plasma anastrozole C(min) showed that there were no statistically significant differences between the Japanese and Caucasian women.. Neither the pharmacodynamic effects of anastrozole on serum oestrogens nor the pharmacokinetics of anastrozole differ between postmenopausal Japanese and Caucasian women. Hence, these findings suggest that the therapeutic benefits of anastrozole in Caucasians will be predictive of the drug's effect in Japanese women and support the use of anastrozole in postmenopausal Japanese women with breast cancer.

Topics: Aged; Anastrozole; Antineoplastic Agents, Hormonal; Aromatase Inhibitors; Asian People; Breast Neoplasms; Enzyme Inhibitors; Estradiol; Estrogens; Estrone; Female; Humans; Japan; Middle Aged; Nitriles; Triazoles; White People

The ability of breast tumors to synthesize sex steroid hormones is well recognized and their local production is thought to play a role in breast cancer development and growth. The aim of this study was to estimate local intra-tumoral and circulating levels of Estrone (E1), Estrone Sulfate (E1S), Estradiol (E2), Estriol (E3), and Testosterone (T) in 33 pre- and postmenopausal women with primary breast cancer in comparison to 12 pre- and postmenopausal women with benign breast tumors. The mean levels of the studied sex hormones were higher in serum and tumor tissue of breast cancer women than those with benign breast tumors apart from Testosterone which showed a significant decrease in pre- and postmenopausal women with breast cancer (P<0.001for follicular phase, P<0.05 for luteal phase, and P<0.005 for postmenopausal). The levels of the five hormones were significantly higher intra-tumoral than in serum of both benign and malignant breast tumor women with E1S as the predominant estrogen. There was only a positive significant correlation between serum and tumor tissue levels of E1 (rs=0.52, P<0.05 for follicular; rs=0.63, P<0.05 for luteal and rs=0.58, P<0.05 for postmenopausal) and a significant correlation between serum and tumor tissue of T (rs=0.64, P<0.05 for follicular; rs=-0.51, P<0.05 for luteal and rs=-0.81, P<0.04 for postmenopausal).

Topics: Adult; Aged; Biomarkers; Breast Diseases; Breast Neoplasms; Carcinoma; Carcinoma, Ductal, Breast; Carcinoma, Lobular; Estradiol; Estriol; Estrone; Female; Fibroadenoma; Follicular Phase; Gonadal Steroid Hormones; Humans; Luteal Phase; Middle Aged; Postmenopause; Premenopause; Testosterone

Topics: Adult; Breast Neoplasms; Dehydroepiandrosterone; Estradiol; Estrogens, Conjugated (USP); Estrone; Female; Gonadal Steroid Hormones; Humans; Middle Aged; Postmenopause; Risk; Sex Hormone-Binding Globulin

The formation of oestrone sulphate has been examined in MCF-7 (oestrogen receptor positive, ER+) and MDA-MB-231 (ER negative, ER-) breast cancer cells. Using intact cell monolayers and a physiological substrate concentration, progesterone (1 microM) and dexamethasone (1 microM) both increased oestrone sulphate formation in MCF-7 cells. In MDA-MB-231 cells, dexamethasone, but not progesterone, increased conjugate formation. A number of growth factors, cytokines and human serum albumin (HSA), which have previously been found to regulate oestrogen synthesis, were also examined for their ability to regulate oestrone sulphate formation. In MCF-7 cells epidermal growth factor, acidic and basic fibroblast growth factors, insulin-like growth factor-type I and insulin all stimulated oestrone sulphate formation. The cytokines, tumour necrosis factor alpha (TNFalpha) and interleukin-1beta also increased conjugate formation in the ER+ cells, as did HSA. In contrast, in MDA-MB-231 cells TNFalpha was without effect and HSA inhibited oestrone sulphate formation. The ability to modulate oestrone sulphate formation in ER+ cells may be an important mechanism to limit the availability of oestrogen to interact with the ER.

Topics: Breast Neoplasms; Cytokines; Epidermal Growth Factor; Estrone; Female; Fibroblast Growth Factor 1; Fibroblast Growth Factor 2; Growth Substances; Humans; Insulin; Insulin-Like Growth Factor I; Insulin-Like Growth Factor II; Interleukin-1; Interleukin-2; Interleukin-6; Kinetics; Receptors, Estrogen; Serum Albumin; Time Factors; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha

Steroid sulphatases regulate the formation of oestrogenic steroids which can support the growth of endocrine-dependent breast tumours. The development of potent steroid sulphatase inhibitors could therefore have considerable therapeutic potential. Several such inhibitors have now been developed of which the most potent to date is oestrone-3-O-sulphamate (EMATE). Unexpectedly, this inhibitor proved to be a potent oestrogen. In an attempt to reduce the oestrogenicity, whilst retaining the potent sulphatase inhibitory properties associated with this type of molecule, a number of A-ring modified derivatives were designed and synthesized. A-ring modified compounds included the 2-methoxy, 2/4-nitro, 2/4-n-propyl and 2/4-allyl EMATE analogues. The ability of these derivatives to inhibit oestrone sulphatase activity was examined using placental microsomes. The allyl-substituted EMATE derivatives were more potent inhibitors than the propyl analogues but were all considerably less potent than EMATE. In contrast, the 2-methoxy and 2/4-nitro analogues were potent sulphatase inhibitors with 4-nitro EMATE being 5 times more active than EMATE. The 4-nitro, 2-methoxy, 4-n-propyl and 4-allyl derivatives were also tested in vivo for their oestrogenicity and ability to inhibit sulphatase activity. While both 4-nitro and 2-methoxy EMATE were potent inhibitors in vivo, 2-methoxy EMATE had no stimulatory effect on uterine growth in ovariectomized rats. The identification of a potent steroid sulphatase inhibitor lacking any oestrogenicity, such as 2-methoxy EMATE, should be of considerable value in evaluating the potential of steroid sulphatase inhibition for breast cancer therapy.

Topics: Animals; Arylsulfatases; Breast Neoplasms; Enzyme Inhibitors; Estrone; Female; Microsomes; Molecular Structure; Organ Size; Ovariectomy; Placenta; Rats; Rats, Inbred Strains; Steryl-Sulfatase; Uterus

Estrogen levels in breast tumors of postmenopausal women are as much as 10 times higher than estrogen levels in plasma, presumably due to in situ formation of estrogen. The major source of estrogen in breast cancer cells may be the conversion of estrone sulfate to estrone by the enzyme estrone sulfatase. Thus, inhibitors of estrone sulfatase have potential for the treatment of estrogen-dependent breast cancers. Several steroidal agents have been developed that are potent estrone sulfatase inhibitors, most notably estrone-3-O-sulfamate. However, these compounds may be metabolized to forms that have undesired actions, including estrogenicity. To avoid the problems associated with a potentially active steroid nucleus, we designed and synthesized a series of (p-O-sulfamoyl)-N-alkanoyl tyramines as nonsteroidal estrone sulfatase inhibitors. These nine compounds differ in the length of their alkanoyl chains. We tested the ability of the (p-O-sulfamoyl)-N-alkanoyl tyramines to inhibit: (a) estrone sulfatase activity in intact cultures of human breast cancer cells (MDA-MB-231); and (b) the growth of estrogen-dependent human breast cancer cells (MCF-7). All of the test compounds (1 microM) inhibited the estrone sulfatase activity of intact MDA-MB-231 cells; however, compounds with a longer alkanoyl chain were more effective than those with a shorter chain. Dose-response analysis indicated an IC50 of 350 nM for (p-O-sulfamoyl)-N-tetradecanoyl tyramine for the inhibition of MDA-MB-231 estrone sulfatase activity. The inhibition of MDA-MB-231 cell estrone sulfatase activity by this compound was found to be irreversible. Cell proliferation assays involved the treatment of estrogen-deprived MCF-7 cells with test compounds (10 microM) in the presence of estrone sulfate (1 microM) as the only source of estrogen. All compounds inhibited cell proliferation to some extent, but the longer-chain analogues again were more effective. Dose-response analysis indicated an IC50 of 38 nM for (p-O-sulfamoyl)-N-tetradecanoyl tyramine for the inhibition of MCF-7 cell proliferation. Our data indicate the utility of (p-O-sulfamoyl)-N-alkanoyl tyramines for the inhibition of breast cancer cell estrone sulfatase activity. Furthermore, our data support the concept that nonsteroidal estrone sulfatase inhibitors may be useful as therapeutic agents for estrogen-dependent breast cancers.

Topics: Breast Neoplasms; Cell Division; Dose-Response Relationship, Drug; Estrogens; Estrone; Humans; Neoplasm Proteins; Neoplasms, Hormone-Dependent; Sulfatases; Tumor Cells, Cultured; Tyramine

We conducted a nested case-control study to prospectively evaluate the relationship of serum estrogens and androgens to risk of breast cancer in postmenopausal women. From 1977 to 1987, 3375 postmenopausal women free of cancer and not taking replacement estrogens donated blood to the Breast Cancer Serum Bank in Columbia, Missouri. Of these, 72 were subsequently diagnosed with breast cancer. For each case, two controls matched on age and date and time of day of blood collection were selected using incidence density matching. The median age of subjects at blood collection was 62 years; the time from blood collection to diagnosis ranged from less than 1 to 9.5 years with a median of 2.9 years. Risk of breast cancer was positively and significantly associated with serum levels of estrogens and androgens. Compared to women in the lowest quartile, those in the highest quartile for non-sex hormone-binding globulin (non-SHBG) bound (bioavailable) estradiol had a relative risk of 5.2 (95% confidence interval [CI] = 1.5-18.5) and those in the highest quartile for testosterone had a relative risk of 6.2 (95% CI = 2.0-19.0). Our results lend considerable support to the hypothesis that serum concentrations of estrogens and androgens are related to the subsequent diagnosis of breast cancer in postmenopausal women.

Topics: Aged; Androstenedione; Breast Neoplasms; Case-Control Studies; Dehydroepiandrosterone Sulfate; Estradiol; Estrone; Female; Gonadal Steroid Hormones; Humans; Middle Aged; Prospective Studies; Risk Factors; Testosterone

This report concerns the evaluation of various estrogens, estrone (El), estradiol (E2), and estrone sulfate (E1S), as well as E1S-sulfatase and aromatase activities in pre- and postmenopausal women with breast cancer. The levels (in picomoles per g; mean +/- SEM) of the various estrogens in the breast tissue from premenopausal patients (n = 11) are: El, 1.4 +/- 0.5; E2, 1.2 +/- 0.6; and E1S, 1.2 +/- 0.3. In postmenopausal patients (n = 23), the values are, respectively, 1.0 +/- 0.4, 1.4 +/- 0.7, and 3.3 +/- 1.9. These concentrations of estrogens in the tumors of postmenopausal patients are significantly higher than those found in plasma. The activity of E1S-sulfatase in both pre- and postmenopausal patients was 50-200 times higher than that of aromatase. E1S-sulfatase and aromatase activities are significantly higher in post-menopausal than in cycling patients. It is concluded that despite the low levels of circulating estrogens in postmenopausal patients, the tissue concentrations of these steroids are several-fold higher than those in plasma, suggesting tumor accumulation of these estrogens. The physiopathology and clinical significance of these high levels of the various estrogens (E1, E2, and E1S) as well as sulfatase and aromatase activities in postmenopausal patients with breast cancer is yet to be explored.

Topics: Adult; Aged; Aromatase; Breast; Breast Neoplasms; Estradiol; Estrogens; Estrone; Female; Humans; Menstrual Cycle; Middle Aged; Postmenopause; Premenopause; Reference Values; Sensitivity and Specificity; Sulfatases

Parity, age at first birth, age at menarche, and a family history of breast cancer have each been associated consistently with breast cancer risk. Whether this increase in risk is mediated, at least in part, through changes in endogenous hormone levels is unclear. We conducted a cross-sectional study of the relationships between these factors and plasma hormone levels in 216 healthy postmenopausal women in the Nurses' Health Study (United States). The hormones evaluated were estradiol, percent and total free estradiol, percent and total bioavailable estradiol, estrone, estrone sulfate, and prolactin. After controlling for age, body mass index (weight/height2), and alcohol use, we observed inverse associations between estrone sulfate and parity (r = -0.15, P = 0.03) and between percent bioavailable estradiol and age at first birth (r = -0.17, P = 0.02). Although women with a family history of breast cancer tended to have higher estrogen levels compared with women without such history, the differences were not statistically significant. Age at menarche was not related significantly to any of the hormones. These data provide some additional evidence that the inverse relationship observed between parity and breast cancer risk may be mediated, at least in part, through decreased estrogen levels. Our data do not support a substantial influence of either family history of breast cancer or age at menarche on postmenopausal estrogen or prolactin levels.

Topics: Adult; Alcohol Drinking; Body Mass Index; Breast Neoplasms; Cohort Studies; Cross-Sectional Studies; Estradiol; Estrogens; Estrogens, Conjugated (USP); Estrone; Female; Humans; Maternal Age; Menarche; Middle Aged; Parity; Postmenopause; Prolactin; Reproductive History; Risk Factors; United States

The evaluation of estrogens (estrone, estradiol, and their sulfates) in the breast tissue of post-menopausal patients with breast cancer indicates high levels, particularly of estrone sulfate (E1S) which is 15-25 times higher than in the plasma. Breast cancer tissue contains the enzymes necessary for local synthesis of estradiol and it was demonstrated that, despite the presence of the sulfatase and its messenger in hormone-dependent and hormone-independent breast cancer cells, this enzyme operates particularly in hormone-dependent cells. Different progestins: Nomegestrol acetate, Promegestone, progesterone, as well as Danazol, can block the conversion of E1S to E2 very strongly in hormone-dependent breast cancer cells. The last step in the formation of estradiol is the conversion of E1 to this estrogen by the action of 17 beta-hydroxysteroid dehydrogenase. This activity is preferentially in the reductive direction (formation of E2) in hormone-dependent cells, but oxidative (E2-->E1) in hormone-independent cells. Using intact hormone-dependent cells it was observed that Nomegestrol acetate can block the conversion of E1 to E2. It is concluded, firstly, that in addition to ER mutants other factors are involved in the transformation of hormone-dependent breast cancer to hormone-independent, this concerns the enzymatic activity in the formation of E2; it is suggested that stimulatory or repressive factor(s) involved in the enzyme activity are implicated as the cancer evolves to hormone-independence; secondly, different drugs can block the conversion of E1S to E2. Clinical trials of these "anti-enzyme" substances in breast cancer patients could be the next step to investigate new therapeutic possibilities for this disease.

Topics: 17-Hydroxysteroid Dehydrogenases; Breast Neoplasms; Estrogens; Estrone; Female; Gene Expression Regulation, Neoplastic; Humans; In Vitro Techniques; Megestrol; Placenta; Progesterone; RNA, Messenger; Sulfatases; Tumor Cells, Cultured

Estrone sulphate (E1S) may be an important estrogen source in breast cancers, particularly in postmenopausal women. Recent studies have shown that tamoxifen inhibits the uptake and metabolism of E1S to estradiol (E2) in cell cultures. To evaluate a possible influence of tamoxifen on E1S disposition in vivo, we measured plasma levels of E1S together with unconjugated estrogens (E1 and E2), androgens (T, A, DHEA and DHEAS), SHBG, FSH and LH in 32 postmenopausal breast cancer patients before and during tamoxifen treatment. In a subgroup of 10 patients, we measured 24 h urinary excretion of estrogen metabolites to evaluate the influence of tamoxifen treatment on estrogen metabolism and total estrogen production. Tamoxifen increased plasma levels of E1S (mean increase of 18.1%, P < 0.05) and the ratio of E1S/E1 (mean increase of 25.7%, P < 0.01) and E1S/E2 (mean increase of 34.7%, P < 0.0005). No significant change in plasma E1 was seen, but plasma E2 was reduced (mean reduction of 12.1%, P < 0.005). The fall in plasma E2 was probably secondary to a fall in plasma T (mean reduction of 11.9%, P < 0.05) due to a reduced ovarian excretion of this androgen. The mechanisms may be a reduced gonadotrophin stimulation of the ovary, as plasma FSH and LH fell by mean values of 45.5 and 48.1%, respectively (P < 0.0001 for both). The increase in plasma E1S was accompanied by a reduced ratio of 2OHE1/E1 in urine (mean reduction of 38.2%, P < 0.025) indicating reduced 2-hydroxylation. Possible mechanisms for these alterations are discussed.

Topics: Aged; Androgens; Breast Neoplasms; Estradiol; Estrogens; Estrone; Female; Follicle Stimulating Hormone; Gonadal Steroid Hormones; Gonadotropins, Pituitary; Humans; Luteinizing Hormone; Middle Aged; Postmenopause; Sex Hormone-Binding Globulin; Tamoxifen; Testosterone

The high serum concentration of estrone sulfate and the presence of estrone sulfatase in breast tumors constitute an important mechanism of local synthesis of estrogens in the tissue. Thus, inhibitors of estrone sulfatase may be effective in the treatment of estrogen-dependent breast cancer. In this study, we synthesized several isostructural analogs of estrone sulfate (estrone-3-methylsulfonate, estrone phosphate, 3-desoxyestradiol-3-methylenesulfonate, and 3-desoxyestrone-3-methylenesulfonate) and tested them on human placental sterylsulfatase. The results were (i) The Ki of 3-desoxyestrone-3-methylenesulfonate 12 and 3-desoxyestradiol-3-methylenesulfonate 7 are more than 100-fold higher than the Ki or KM values for estrone sulfate, (ii) As compared to estrone sulfate, the Ki value for estrone-3-methylsulfonate 2 is about 30-fold higher, while estrone phosphate 3 is bound by the sulfatase with roughly the same affinity as estrone sulfate. The results shed some light on the electronical and sterical requirements for high affinity binding to the enzyme.

Topics: Binding Sites; Breast Neoplasms; Estradiol; Estrogens; Estrone; Female; Humans; Mesylates; Placenta; Sulfatases

A major obstacle to the understanding of the mechanisms of action of aromatase inhibitors in breast cancer is the observation that plasma estrogens are sustained at about 30-50% of their control levels despite 85-95% inhibition of the conversion of tracer androstenedione (A) to estrone (E1). The discrepancy could be due to lack of sensitivity of current RIAs. Due to low levels of plasma estradiol (E2) (mean about 20 pM) and E1 (mean about 75 pM) in postmenopausal women, it is difficult to develop RIA methods with the sensitivity required to detect > 90% suppression from baseline. In contrast, the plasma level of the estrogen conjugate estrone sulphate (E1S) is substantially higher (mean level about 400 pM). This paper describes a new assay to measure plasma E1S in the low range aiming to detect > 95% suppression of E1S from baseline values in patients treated with aromatase inhibitors. E1S was separated from unconjugated estrogens, hydrolysed and purified as unconjugated E1. E1 was subsequently reduced to E2, purified, and measured by a highly sensitive RIA using oestradiol-6-(O-carboxymethyl) oximino-(2(-)[125I]iodohistamine as ligand. The sensitivity limit of the method was 2.7 pM. Patients on treatment with the aromatase inhibitors formestane or aminoglutethimide or both drugs in concert were found to have plasma levels of E1S ranging from 3 to 274 pM with a mean suppression of 78, 86 and 95%, respectively, compared to baseline, a lower suppression than that reported in previous trials with these drugs.

Topics: Aminoglutethimide; Androstenedione; Antineoplastic Combined Chemotherapy Protocols; Aromatase Inhibitors; Breast Neoplasms; Enzyme Inhibitors; Estrone; Female; Humans; Hydrolysis; Menopause; Radioimmunoassay; Sensitivity and Specificity

The metabolism of [3H]estrone sulfate ([3H]E1S) was studied in normal breast tissue from 10 premenopausal women without oral contraceptives (OC), in 12 OC users and in 9 untreated postmenopausal women. [3H]E1S was converted into estrone ([3H]E1) and estradiol-17 beta ([3H]E2) by tissue samples from all three groups of women, with only minor formation of other unconjugated compounds. The rate of [3H]E2 formation was significantly higher in premenopausal women without OC than in postmenopausal women. Among premenopausal women, OC users had a significantly lower rate of total hydrolysis and of [3H]E1 formation than non-users. The rate of total hydrolysis of [3H]E1S in normal breast tissue from all three groups of women was similar to that in muscle, but the rate of [3H]E2 formation was ten times higher. Both total hydrolysis rate and rate of [3H]E2 formation were significantly lower in normal breast tissue than in breast carcinoma and in normal and neoplastic endometrium. The specific ability of normal breast tissue to convert E1S into the terminal biologically active estrogen E2 may be important for estrogenic stimulation of the breast in subjects with low circulating E2 levels. The lower rate of E1 formation in OC users may reflect an inhibitory effect of the progestagen compound in such preparations.

Topics: Adolescent; Adult; Aged; Breast; Breast Neoplasms; Contraceptives, Oral; Endometrial Neoplasms; Estradiol; Estrone; Female; Humans; Menopause; Middle Aged; Postmenopause; Premenopause; Progesterone; Tritium

The effects of triptorelin (Decapeptyl) and heparin, alone or in combination, on the intracellular concentration of estradiol (E2) after incubation of estrone sulfate (E1S) with the MCF-7 mammary cancer cells was investigated. Although heparin (10 mg/l culture medium) or Decapeptyl (5 x 10(-7) or 5 x 10(-5) mol/l) did not affect the levels of radioactive E2 after incubation with [3H]E1S, the combination of Decapeptyl and heparin significantly decreased the radioactive uptake and the intracellular concentrations of [3H]E2. In the absence of Decapeptyl and heparin incubations with E1S, the resulting E2 concentration (in nmol/kg DNA +/- SD) was 558 +/- 44; after heparin (10 mg/l) plus Decapeptyl (5 x 10(-7) or 5 x 10(-5) mol/l) the values were 389 +/- 55 and 165 +/- 18, respectively. It is concluded that Decapeptyl with heparin can decrease very significantly the conversion of E1S to E2 in MCF-7 cells, an observation that suggests new possibilities for the control of E2 in hormone-dependent breast cancer.

Topics: Breast Neoplasms; Estradiol; Estrone; Heparin; Humans; Triptorelin Pamoate; Tumor Cells, Cultured

In the present studies the action of Danazol on the conversion of estrone sulfate (E1S) to estradiol (E2) as well as on the sulfatase activity in the MCF-7 and T-47D, hormone-dependent, and MDA-MB-231, hormone-independent, mammary cancer cell lines was explored. Using intact cells we observed that Danazol blocks very significantly the radioactivity uptake and the conversion of [3H]E1S to E2 in all the cells studied. In particular, a very strong effect (85% decrease of these parameters versus the control values) is observed in the T-47D cells. In another series of studies using cell homogenates it is observed that Danazol inhibits the sulfatase activity in all these cell lines. The effect of Danazol is dose-dependent and significant from a concentration of 1 microM. At concentrations of 8 microM E1S, 10(-5) M Danazol, the inhibition of sulfatase activity is 38% in MCF-7, 36% in MDA-MB-231, and 27% in T-47D cells. Analysis by Lineweaver-Burk plot shows that the inhibitory effect is competitive. As E1S is one of the main sources of E2 in human mammary tumors, the present data could open new possibilities for therapeutic applications in hormone-dependent breast cancer.

Topics: Breast Neoplasms; Danazol; Estradiol; Estrone; Humans; Sulfatases; Tumor Cells, Cultured

Estradiol levels in breast tumors from post-menopausal women are similar to those in pre-menopausal women even though plasma estrogens are much lower after the menopause. In situ estrogen production by the tumor provides a potential means of maintaining high estradiol levels in post-menopausal breast cancer tissue. The estrone sulfatase pathway has been proposed as the mediator of in situ estrogen production. A number of studies suggest that estrone sulfate may be converted into estradiol in breast tumors via the catalytic activity of estrone sulfatase and 17 beta-hydroxysteroid dehydrogenase. However, these studies used pharmacologic levels of estrogen sulfates and have not shown that physiologic levels can support biologic effects. Accordingly, the present study examined the dose relationship of estrone sulfate to a variety of biologic endpoints in MCF-7 breast cancer cells in culture. These cells converted physiologic concentrations of estrone sulfate to quantities of free estradiol capable of stimulating cell growth. Under these conditions, the nuclear steroids observed were free estrone and estradiol. Increase in cell number after 6 days of exposure to steroid required 100 nM estrone sulfate. However, S-phase, a more sensitive measure of cell proliferation, was stimulated by 0.1 nM estrone sulfate, a clearly physiologic concentration. Stimulation of estrogen-dependent protein markers such as pS2 and progesterone receptor required much higher concentrations of estrone sulfate. These effects were mediated through the estrogen receptor since the pure anti-estrogen, ICI 164384, blocked all effects produced by estrone sulfate. While it has been suggested that anti-estrogens may partly exert their effects by inhibition of sulfatase and 17 beta-hydroxysteroid dehydrogenase, this did not occur under our experimental conditions. These data provide evidence of the relevance of the estrone sulfatase pathway since biologic effects can be demonstrated in response to physiologic concentrations of estrone sulfate.

Topics: Biological Transport; Breast Neoplasms; Cell Division; Cell Nucleus; Cells, Cultured; Estradiol; Estrone; Female; Humans; In Vitro Techniques; Neoplasm Proteins; Polyunsaturated Alkamides; Proteins; Receptors, Progesterone; S Phase; Sulfatases; Trefoil Factor-1; Tumor Suppressor Proteins

We have previously shown that human breast cancer is autonomous in the regulation of its intra-tissue oestradiol concentration. Breast fatty tissue does not have this capacity, but rather reflects changes in the peripheral oestradiol concentration. To further evaluate the relative contribution of breast cancer and fatty tissue to the maintenance of tumour oestradiol we investigated whether a tumour-directed gradient in aromatase activity and oestrogen levels existed in mastectomy specimens. No such gradient was found, however, for aromatase, oestrone, oestradiol and their sulphates. Aromatase activity (expressed per gram of tissue) and the concentrations of oestradiol, oestradiol sulphate and oestrone sulphate were higher in tumour than in breast fatty tissue. Fatty tissue had a higher oestrone concentration. It is tentatively concluded that breast tumour aromatase activity is more important for the maintenance of tumour oestradiol levels than aromatase in breast fatty tissue.

Topics: Adipose Tissue; Aromatase; Breast Neoplasms; Estradiol; Estrogens; Estrogens, Conjugated (USP); Estrone; Female; Humans; Menopause; Receptors, Estrogen; Receptors, Progesterone

In the present study we have explored the actions of the progestagen R5020 (Promegestone: 17 alpha, 21-dimethyl-19-nor-pregna-4, 9-diene-3,20-dione) and progesterone on the uptake of [3H]estrone sulfate ([3H]E1S) and its conversion to estradiol (E2) by two hormone-dependent mammary cancer cell lines: MCF-7 and T-47D. R5020 or progesterone significantly decreased the uptake of [3H]E1 and its conversion to (E2). In the cells of the two lines, R5020 or progesterone (5 x 10(-6) M) decreased the E2 concentrations by 2-3 times in relation to the levels in untreated cells. E1S (1 x 10(-7) M) also increased expression of the progesterone receptor (PR) and both R5020 (5 x 10(-6) M) and progesterone (5 x 10(-6) M) blocked this stimulatory action of E1S in cells of both cell lines. As E2 is one of the main factors of cancerization in the breast and estrone sulfate is quantitatively the most important precursor of E2 in this tissue, the decrease of E2 by these progestagens could open new possibilities for the control of E2 in the breast cancer tissue.

Topics: Biotransformation; Breast Neoplasms; Estradiol; Estrone; Female; Humans; Neoplasms, Hormone-Dependent; Progesterone; Promegestone; Receptors, Progesterone; Tritium; Tumor Cells, Cultured

Conversion of oestrone sulphate to oestrone has been suggested to make a major contribution to the level of oestrone found in breast tissues. In order to examine the ability of breast tissues to take up oestrone sulphate (E1S), 3H E1S or E1-35S was infused into postmenopausal women with advanced breast cancer. For 3 subjects infusion of 3H E1S was repeated after treatment with Danazol, a potential inhibitor of oestrone sulphatase activity. After infusion of 3H E1S significant levels of 3H E1S were detected in normal and malignant breast tissues (tissue: plasma ratios 0.14 +/- 0.13 and 0.24 +/- 0.12 respectively, mean +/- S.D., n = 5). Similar 3H E1S tissue: plasma ratios were detected after infusions of 3H E1 indicating that the 3H E1S detected in breast tissues after infusion of 3H E1S may have originated from the hydrolysis of 3H E1S in tissues other than the breast, with subsequent uptake and sulphation in breast tissues. After infusion of E1-35S no significant levels of radioactivity were detectable in normal or malignant breast tissues. Treatment with Danazol had no significant effect on tissue levels of 3H E1S or on the CRE1S E1 or MCR-E1S. It is concluded that oestrone sulphate, as such, is not taken up by breast tissues and that any contribution that oestrone sulphate makes to the oestrogen content of breast tissues will depend upon prior hydrolysis.

Topics: Aged; Breast; Breast Neoplasms; Danazol; Estrone; Female; Humans; Menopause; Middle Aged; Sulfatases; Sulfates; Tritium

CGS 16949A (fadrozole hydrochloride), a potent cytochrome P450-mediated steroidogenesis inhibitor, blocks aromatase at low doses, but other biosynthetic steps at higher concentrations. Recent studies demonstrated inhibition of C11-hydroxylase, corticosterone methyloxidase-II, and deoxycorticosterone to corticosterone conversion with this agent at some-what higher concentrations than those required for blockade of aromatase. Based upon phase I studies, we postulated that relatively selective inhibition of aromatase might be possible if sufficiently low doses of CGS 16949A were used. A phase II study in 54 postmenopausal women with metastatic breast cancer examined the effects of low dose CGS 16949A on estrogen, mineralocorticoid, and glucocorticoid secretion. Two dose schedules and two dose levels were chosen based upon our prior dose escalation protocol study. Plasma estrone, estradiol, and estrone sulfate as well as urinary estrone and estradiol fell equally with 1.8-4 mg CGS 16949A given either on a twice daily or three times daily dose schedule. Isotopic kinetic studies demonstrated an 84% decrease in the rate of conversion of androstenedione to estrone to 0.40 +/- 0.07% (patients receiving 1.8-4 mg CGS 16949A daily). With these three regimens, basal levels of aldosterone and cortisol did not change significantly over a 12-week period of observation. Clinical examination, plasma electrolytes, and urinary sodium/potassium ratios suggested no biological evidence of mineralo-corticoid deficiency. ACTH-stimulated cortisol concentrations, however, were blunted at each dose level compared to pretreatment values. Nonetheless, peak responses exceeded 550 nmol/L, or a basal to peak difference of 190 nmol/L or greater, in 97% of instances. This probably reflected inhibition of C11-hydroxylase, since basal and ACTH-stimulated levels of 11-deoxycortisol were increased in response to CGS 16949A. Androstenedione and 17 alpha-hydroxyprogesterone also exhibited an upward trend in response to drug treatment. ACTH-stimulated aldosterone levels were blunted to a greater extent than those of cortisol, probably as a reflection of corticosterone methyloxidase type II blockade. Overall, the results suggest that CGS 16949A, at doses of 1.8-2 mg daily, blocks aromatase effectively and does not produce clinically important inhibition of cortisol or aldosterone biosynthesis. Thus, this agent can probably be used safely without glucocorticoid or mineralocorticoid supplementation.

Topics: 17-alpha-Hydroxyprogesterone; Adrenocorticotropic Hormone; Aldosterone; Androstenedione; Aromatase Inhibitors; Breast Neoplasms; Estradiol; Estrone; Fadrozole; Female; Humans; Hydrocortisone; Hydroxyprogesterones; Imidazoles; Kinetics; Menopause; Nitriles

The pyridylglutarimide 3-ethyl-3-(4-pyridyl)-piperidine-2,6-dione (PyG) is a novel inhibitor of aromatase that was shown to cause effective suppression of plasma oestradiol levels in postmenopausal patients. In four patients receiving oral doses of PyG (500 mg) twice daily for 3-4 days, oestradiol levels fell to 31.1% +/- 6.3% of baseline values within 48 h and remained suppressed during treatment. Of a further six patients who received oral PyG (1 g) as a single dose, five had quantifiable oestradiol levels. Oestradiol suppression was sustained for 36 h and recovery correlated with a fall of PyG concentrations below a threshold value of ca. 2 micrograms/ml. The pharmacokinetics of PyG were non-linear and, when fitted to the integrated Michaelis-Menten equation, yielded good parameter estimates for Co (21.7 +/- 1.82 micrograms/ml), Km (2.66 +/- 0.68 micrograms/ml) and Vmax (0.86 +/- 0.06 micrograms ml-1 h-1). On subsequent repeated dosing with PyG, both the Km (4.31 +/- 0.48 micrograms/ml) and the Vmax (1.83 +/- 0.13 micrograms ml-1 h-1) values increased and recovery from oestradiol suppression was more rapid, indicating that PyG induces its own metabolism.

Topics: Aminoglutethimide; Antineoplastic Agents; Breast Neoplasms; Estradiol; Estrogens, Conjugated (USP); Estrone; Female; Humans; Middle Aged; Time Factors

The ovarian and pituitary functions of 64 operable breast cancer patients undergoing adjuvant therapy with cytotoxic chemotherapy and/or tamoxifen were investigated. The post menopausal patients, divided into 3 treatment groups, one with tamoxifen alone, one with tamoxifen and chemotherapy and the other with chemotherapy alone had serum estradiol 17-beta (E2) and progesterone levels lower than the evaluable limits. Although there was no significant difference in the level of estrone sulfate (E1-S) between these three groups, the level of lutainizing hormone (LH) and follicle stimulating hormone (FSH) in the patients treated with tamoxifen alone and tamoxifen and chemotherapy were significantly lower than those treated with chemotherapy alone. The decrease in gonadotropin levels induced by tamoxifen treatment was reversible as it appeared after the initiation of tamoxifen and recovered after its cessation. In the premenopausal patients, a group treated with tamoxifen and chemotherapy had significantly higher E1-S, E2 and progesterone levels and significantly lower gonadotropin levels than a group treated with chemotherapy alone or one treated with a cyclophosphamide regimen. These increases in the levels of estrogen and progesterone were also reversible, and induced by tamoxifen. Thus, adjuvant endocrinochemotherapy causes profound alteration in the hypothalamo-pituitary-ovarian axis and therefore, monitoring a variety of hormonal levels is thought to be necessary for assessing the consequences of adjuvant therapy in breast cancer patients, especially in premenopausal patients using tamoxifen.

Topics: Aged; Antibiotics, Antineoplastic; Breast Neoplasms; Cyclophosphamide; Drug Evaluation; Drug Therapy, Combination; Estradiol; Estrone; Female; Follicle Stimulating Hormone; Gonadotropins; Humans; Luteinizing Hormone; Middle Aged; Progesterone; Tamoxifen

Topics: Aged; Antineoplastic Agents; Aromatase Inhibitors; Breast Neoplasms; Estrone; Fadrozole; Humans; Imidazoles; Male; Middle Aged; Nitriles; Time Factors

The influence of oral high dose progestin (medroxyprogesterone acetate, MPA and megestrol acetate, MA) treatment on serum hormone levels was studied in ten postmenopausal women with advanced breast cancer. The gonadotropins and ACTH were significantly reduced by greater than 50 and 23%, respectively. Serum cortisol, DHEAS, androstenedione and testosterone were all significantly reduced (mean reduction between 64 and 76%), while serum estrone, estradiol and estrone sulfate were significantly reduced by 20-30%. Sex hormone binding globulin (SHBG) and corticosteroid binding globulin (CGB) were reduced by 68 and 25%, respectively. Although the dose of MA used (160 mg/day) was only 1/6 of the MPA dose (1000 mg/day), the mean serum level of MA was 2-fold higher than the mean serum level of MPA. MPA treatment gave a more pronounced suppression of SHBG than MA treatment, while estrone sulfate levels were more suppressed by MA. These findings suggest a differential effect of MPA and MA on certain plasma hormones, possibly of importance for understanding the mechanism of action of the two drugs. The reduction of estrone sulfate may be beneficial for the action of MA against breast cancer.

Topics: Aged; Androgens; Breast Neoplasms; Estrogens; Estrone; Female; Hormones; Humans; Medroxyprogesterone; Megestrol; Megestrol Acetate; Middle Aged; Sex Hormone-Binding Globulin; Transcortin

Different estrogen-3-sulfates (estrone-3-sulfate, estradiol-3-sulfate, and estriol-3-sulfate) can provoke important biologic responses in different mammary cancer cell lines; there is a significant increase in progesterone receptor. However, no significant effect was observed with estrogen-17-sulfates. The reason for the biologic response of estrogen-3-sulfates is that these sulfates are hydrolyzed, and no sulfatase activity for C17-sulfates is present in these cell lines. [3H]-Estrone sulfate is converted in a very high percentage to estradiol (E2) in different hormone-dependent mammary cancer cell lines (MCF-7, R-27, and T47D), but very little or no conversion was found in hormone-independent mammary cancer cell lines (MDA-MB-231 and MDA-MB-436). Different antiestrogens (tamoxifen and its derivatives) and another potent antiestrogen, ICI 164,384, significantly decrease the concentration of estradiol after incubation of estrone sulfate with the different hormone-dependent mammary cancer cell lines. No significant effect in the uptake and conversion of estrone sulfate was observed in hormone-independent mammary cancer cell lines. The data indicate that sulfatase activity for estrone sulfate is very low in the hormone-independent cell lines; however, comparative kinetic studies carried out after homogenization of MCF-7 and MDA-MB-436 cells show that sulfatase activity is similar, suggesting different mechanisms in the hydrolysis of estrone sulfate in hormone-dependent and hormone-independent cell lines. Progesterone also provokes a significant decrease in uptake and in estradiol levels after incubation of [3H]-estrone sulfate with the MCF-7 cell line. It is concluded that estrogen sulfates can play an important role in the biologic response of estrogens in breast cancer and that control of sulfatase and 17-hydroxysteroid dehydrogenase activities are key steps in the concentration and ability of estradiol in the mammary cancer cell line.

Topics: Breast Neoplasms; Estradiol; Estriol; Estrone; Female; Humans; Menstruation; Polyunsaturated Alkamides; Progesterone; Receptors, Progesterone; Tamoxifen; Tumor Cells, Cultured

Topics: Androgens; Breast; Breast Neoplasms; Estradiol; Estrone; Female; Humans; Menopause; Steroids

Estrone sulfate (E1-S) has been shown to be quantitatively the most important estrogen in peripheral blood. But, the physiological and/or pathological role of E1-S is not yet clarified. At present, we tried to clarify it using tissue cultures. In tissue cultures of human endometrium, secretory endometrium showed higher activity of estrone sulfatase (E1----E1-S) than proliferative endometrium. Progesterone added in the medium induced an increase of estrone sulfotransferase in the proliferative endometrium. The results suggest a reducing effect of estrogen by progesterone in secretory endometrium in physiological conditions. Estrogen dependent malignant tumors (breast cancer, endometrial cancer) have high estrone sulfatase. It converts E1-S to E1 (----E2) which are abundant in these tumors. Ishikawa cell line increased estrone sulfotransferase activity with progesterone, somewhat like the physiological conditions. From out study in vivo, there is a possibility of some ameliorative effects of E1-S on the central nervous system of patients with senile dementia (Alzheimer's type). Effects of E1-S on central nerves were investigated using tissue cultures.

Topics: Alzheimer Disease; Breast Neoplasms; Culture Techniques; Endometrial Neoplasms; Endometrium; Estradiol Dehydrogenases; Estrone; Female; Humans; Progesterone; Sulfatases; Sulfotransferases; Sulfurtransferases

Plasma level, plasma clearance, production rate and interconversions of oestrone and oestrone sulphate were measured in six breast cancer patients receiving aminoglutethimide therapy. Three additional patients had the production rate of oestrone sulphate investigated. Plasma oestrone and oestrone sulphate levels were reduced by a mean of 46% (P less than 0.05) and 71% (P less than 0.005) respectively. These alterations were due to a combined action of aminoglutethimide inhibiting oestrogen production but also increasing oestrogen metabolism. While oestrone and oestrone sulphate production rate was reduced by a mean of 31% (P less than 0.05) and 41% (P less than 0.005) respectively, the plasma clearance rate of oestrone was found to be increased by a mean of 30% (P less than 0.05), and the plasma clearance rate of oestrone sulphate was increased by a mean of 112% during aminoglutethimide treatment. The fraction of oestrone sulphate converted into plasma oestrone was reduced by 52% (P less than 0.05), the transfer of circulating oestrone into sulphate was non-significantly reduced by a mean of 16%. The findings in this investigation show that aminoglutethimide treatment influences oestrogen disposition by mechanisms unrelated to aromatase inhibition. The possibility that such effects might be partly responsible for the mechanism of action of aminoglutethimide in advanced breast cancer should be considered.

Topics: Aged; Aminoglutethimide; Breast Neoplasms; Estrogens, Conjugated (USP); Estrone; Female; Humans; Middle Aged

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.

Topics: Adipose Tissue; Breast Neoplasms; Estradiol; Estrogens, Conjugated (USP); Estrone; Female; Humans; Middle Aged; Radioimmunoassay; Sulfatases; Uterine Neoplasms

The biological effects of the anti-estrogen ICI 164.384 on proliferation, on progesterone receptor (PR) and on the conversion of estrone sulfate to estradiol in the MF-7 mammary cancer cells were studied. This anti-estrogen at the low concentration (10(-9)-10(-10) M) blocks cell proliferation and significantly decreases the levels of PR. ICI 164.384 also provokes a very important diminution in the conversion of estrone sulfate to estradiol. It is concluded that the study of the biological responses of this potent anti-estrogen opens new possibilities in the knowledge of the different steps of the mechanism of action of anti-estrogens in mammary cancer cells.

Topics: Breast Neoplasms; Cell Division; DNA; Estradiol; Estrogen Antagonists; Estrone; Humans; Polyunsaturated Alkamides; Receptors, Progesterone; Tumor Cells, Cultured

Plasma levels of estrone and estrone sulfate were measured in 16 postmenopausal women with advanced breast cancer before and during chronic aminoglutethimide therapy. Aminoglutethimide caused a significant reduction in plasma estrone (mean 36%, P less than 0.025) and estrone sulfate (mean 65%, P less than 0.001). The estrone/estrone sulfate ratio was increased by a mean of 84% (P less than 0.0025). These results suggest that aminoglutethimide influences plasma estrone sulfate by mechanisms unrelated to aromatase inhibition. The findings in this study are consistent with previous results suggesting that aminoglutethimide treatment enhances the rate of estrone sulfate metabolism. This biochemical effect of aminoglutethimide treatment could be a contributory factor to the drugs mechanism of action.

Topics: Adult; Aged; Aminoglutethimide; Analysis of Variance; Aromatase Inhibitors; Breast Neoplasms; Estrone; Female; Humans; Middle Aged

R-27 cells, a tamoxifen-resistant clone of MCF-7 mammary cancer cells, were used to study the effect of tamoxifen and its derivatives (4-hydroxytamoxifen, N-desmethyltamoxifen and cis-tamoxifen) on the conversion of estrone sulfate to estradiol. The present data indicate that (1) tamoxifen, 4-hydroxytamoxifen, N-desmethyltamoxifen and cis-tamoxifen inhibit the uptake of the radioactivity after incubation of these triphenylethylene derivatives with [3H]-estrone sulfate; (2) there is a significant decrease of the conversion of estrone sulfate to estradiol by these antiestrogens; (3) the concentrations of estradiol (cytosol + 0.6 M KCl nuclear extract) which are 293 +/- 50 pg/mg DNA in the control studies (estrone sulfate alone), diminish to 26 +/- 5 pg/mg DNA after addition of tamoxifen, to 9 +/- 2 with 4-hydroxytamoxifen, to 24 +/- 7 with N-desmethyltamoxifen and to 32 +/- 6 with cis-tamoxifen. It is concluded that estrone sulfate can play an important role in the biological responses to estrogens in this breast cancer cell line and tamoxifen and its derivatives block the conversion of estrone sulfate to estradiol. The decrease in concentration of estradiol could be explained by the presence of the estrogen receptor system but other ways of the action of antiestrogens remain to be explored.

Topics: Breast Neoplasms; Cell Line; Drug Resistance; Estradiol; Estrogens, Conjugated (USP); Estrone; Female; Humans; Kinetics; Tamoxifen; Tritium

Reports of estrone (E1) and dehydroepiandrosterone (DHEA) sulfatase (sulfohydrolase) activities within many human breast cancers have prompted us to undertake the identification and partial characterization of these enzyme activities within MCF-7 human breast cancer cells. Enzyme assays were performed within subcellular preparations and intact cultures by quantifying the total nonpolar 3H-labeled metabolites formed from [3H]E1 sulfate (E1S) and [3H]DHEA sulfate (DHEAS). The results have shown that the hydrolysis of each steroid sulfate is mediated by different particulate enzymes, which demonstrate optimal activity between pH 6.0-7.0. The analysis of enzyme kinetic data showed the Km values of E1S and DHEAS for their enzymes to be approximately 6.3 and 3.6 microM/L, respectively. Neither enzyme was subject to product inhibition. Androsterone sulfate and pregnenolone sulfate produced significant inhibition of E1, but not DHEA, sulfatase activity. E1S inhibited DHEA sulfatase competitively, with an approximate Ki of 11 microM, whereas DHEAS inhibited E2 sulfatase in a noncompetitive fashion, demonstrating an approximate Ki of 0.6 microM. Studies carried out with intact MCF-7 cultures using physiological concentrations of 3H-labeled E1S (2 nM) or DHEAS (1 microM) showed the accumulation of nonpolar metabolites during a 20-h incubation period. When cultures were incubated with similar concentrations of both steroid sulfates the apparent intracellular activity of E1 sulfatase was reduced by approximately 70%, whereas DHEA sulfatase activity remained unchanged. The results of these studies confirm the ability of MCF-7 cells to hydrolyze extracellular E1S and DHEAS, indicate that these reactions are mediated by different enzymes, and demonstrate that DHEAS is a potent inhibitor of MCF-7 E1 sulfatase. Circulating DHEAS, therefore, may substantially limit the ability of most postmenopausal breast cancers to use E1S as a substrate for intracellular estrogen biosynthesis.

Topics: Breast Neoplasms; Dehydroepiandrosterone; Dehydroepiandrosterone Sulfate; Estrone; Female; Humans; Hydrolysis; Kinetics; Steryl-Sulfatase; Sulfatases; Tumor Cells, Cultured

Estrone and estradiol-17 beta concentration in breast cancer tissue are reported to be an order of magnitude higher than those of circulating plasma in breast cancer patients. This high level of estrogen is provided by local production from estrone sulfate (E1-S) through the sulfatase pathway. Then serum E1-S level was determined using direct radioimmunoassay method in order to monitor the estrogen kinetics of post-operative breast cancer patients. Peri-operative sequential E1-S determination was carried out in 10 patients. Among them, extremely higher level, as compared with normal menstruating level of 625-2670pg/ml, was observed just after an administration of tamoxifen (three weeks after operation) in two of 5 pre-menopausal patients. In order to evaluate the effect of tamoxifen on serum level of E1-S in post-operative pre-menopausal patients, serum E1-S level in 42 post-operative outpatients was examined. Although there was no difference in the average level of E1-S in post-menopausal patients treated with or without tamoxifen, average E1-S level in pre-menopausal patients treated with tamoxifen as adjuvant therapy was significantly higher than that in patients without tamoxifen. These results suggests that the administration of tamoxifen to premenopausal patients should be reconsidered from a view point of the estrogen kinetics.

Topics: Adult; Aged; Breast Neoplasms; Combined Modality Therapy; Estrone; Female; Humans; Kinetics; Menopause; Middle Aged; Postoperative Period; Radioimmunoassay; Reference Values; Tamoxifen

The human mammary cancer cell line MCF-7 in culture was used to study the effect of tamoxifen and its derivatives: 4-hydroxytamoxifen (4-OH-Tam), N-desmethyltamoxifen (Dem-Tam) and cis-tamoxifen (cis-Tam) on the uptake and conversion of [3H]estrone sulfate (3H-E1S) to estradiol (E2). When [3H]-E1S (4 X 10(-9) M) was incubated by itself (control) a great proportion of the radioactivity was found as [3H]E2, predominantly in the nuclear fraction. All of the anti-estrogens (10(-6) M - 10(-5) M) studied decreased the total uptake of radioactivity by the cells by 50-60% and the quantity of E2 formed. The calculated concentrations (in pg/mg DNA +/- S.E.M.) of E2 (cytosol + 0.6 M KCl nuclear extract) with the anti-estrogens at 10(-5) M were as follows: control 56 +/- 3; Tam treated cells 4 +/- 1; + 4-OH-Tam 2 +/- 1; + Dem-Tam 5 +/- 2; + cis-Tam 8 +/- 4. A significant decrease in the concentrations of E2 was also observed in the mitochondria-microsomal fractions after the different treatments. It is suggested that the MCF-7 cells can use estrone-3-sulfate as a source of E2 and that the inhibitory effect of tamoxifen and its derivatives on the conversion of this sulfate to E2 could be involved in the anti-estrogenic process of these triphenylethylene derivatives.

Topics: Breast Neoplasms; Cell Line; Estradiol; Estrone; Female; Humans; Tamoxifen; Tumor Cells, Cultured

The biological responses, the metabolism and the ultrastructural modifications provoked by estrone sulfate in the MCF-7 mammary cancer cell line are studied. The data indicate: 1) A fraction of estrone sulfate is hydrolyzed and the freed hormone is sufficient to elicit a biological response (progesterone receptor). 2) Using [3H]estrone sulfate, 24 h after culture, it is observed that the great part of the radioactive material in the cells is in the form of unconjugated estrogens. 3) The main transformation product of [3H]estrone sulfate is estradiol. This is found particularly in the nucleus. 4) Tamoxifen inhibits very significantly the conversion of estrone sulfate into estradiol. 5) Electronmicroscopic observations indicate that the estrone sulfate provokes an important development in the secretory system. In conclusion, it is suggested that the estrone sulfate can play an important role in the response to estrogens in human mammary cancer.

Topics: Breast Neoplasms; Cell Line; Estrone; Female; Humans; Hydrolysis; Receptors, Progesterone; Tamoxifen

Topics: Aminoglutethimide; Breast Neoplasms; Danazol; Dehydroepiandrosterone; Dehydroepiandrosterone Sulfate; Drug Administration Schedule; Estrogens; Estrone; Female; Humans; Pregnadienes; Sex Hormone-Binding Globulin; Tamoxifen

The biological effects and ultrastructural alterations by different estrogen-3-sulfates (E1-3-S and E2-3-S) and estradiol-17-sulfate (E2-17-S) were studied in the MCF-7 mammary cancer cell line in culture. The estrogen-3-sulfates very significantly stimulated the progesterone receptor (PR). The values (in pmoles/mg DNA +/- SE) were: control, 0.46 +/- 0.09; E1-3-S, 2.24 +/- 0.30, and E2-3-S, 2.56 +/- 0.45. The value of PR after E2-17-S incubation (0.56 +/- 0.24) was similar to the non-treated cells. The PR values obtained by the incubation of unconjugated estrone and estradiol were: 2.63 +/- 0.45 and 2.27 +/- 0.36, respectively. Analysis of the unconjugated estrogens in the medium indicated significant hydrolysis of estrogen-3-sulfates but not of E2-17-S. Using [3H]-E1-3-S, an important transformation was observed inside the cells, a great part being converted to estradiol (greater than 60% in the nuclear fraction). Electron microscopic examination indicated alterations in the secretory system after incubation with estrogen-3-sulfates similar to those obtained with unconjugated estradiol. The effect provoked by E2-17-S was significantly less than for the other sulfates. As estrogen sulfates are quantitatively the most important form of estrogens in the mammary gland, it is suggested that estrogen-3-sulfates play an important role in the biological responses to estrogens in breast cancer.

Topics: Breast Neoplasms; Cell Line; Dose-Response Relationship, Drug; Estradiol; Estrogens, Conjugated (USP); Estrone; Female; Humans; Microscopy, Electron; Receptors, Progesterone; Tissue Distribution

Local formation of estradiol in human breast tumors could provide a more important source of estrogen than is delivered from plasma. Prior studies have suggested that estrone is primarily synthesized from estrone sulfate. The enzyme 17 beta-hydroxysteroid dehydrogenase (HSD) would be required to convert estrone to estradiol. This study characterized HSD in 1000 X g supernatants from human breast tumors. Estradiol synthesis was linearly related to tissue concentration or time over the range studied. Cofactor requirements varied with estrone concentration. High and low affinity sites were found in 50% of tissues studied, while the remainder contained only low affinity sites. Screen assays showed measurable activity in all 42 samples tested. This activity ranged from 0.73- greater than 100 nmol estrone synthesized/g protein/hr, with a median activity of 5.9 nmol/g/hr. We evaluated the biological relevance of the sulfatase-HSD pathway by testing the ability of estrone sulfate to stimulate colony formation in soft agar cultures of nitrosomethylurea-induced rat mammary tumors. The maximally effective concentration ranged from 10(-7) to 10(-4)M. Significant stimulation of colony formation was observed in 7 of 8 experiments. The estrone sulfate stimulation pattern was similar to that previously observed with estradiol. Of the 3H-estrone sulfate added to the dishes, 20-98% was recovered as estrone and 0.2-6% as estradiol. These studies suggest that the requisite enzymes are present in human breast tumors for conversion of estrone sulfate to estradiol, and that this pathway may be biologically significant.

Topics: 17-Hydroxysteroid Dehydrogenases; Animals; Breast Neoplasms; Cells, Cultured; Chromatography, Thin Layer; Estradiol; Estrone; Female; Humans; Kinetics; Mammary Neoplasms, Experimental; Rats; Rats, Inbred Strains; Receptors, Estrogen; Receptors, Progesterone

Using a [4-14C]estradiol bolus injection technique possible effects of AG administration on estrogen metabolism were studied in seven patients. No alterations in steroid disposition were seen after a short term AG treatment. Chronic AG administration produced no change in mean estradiol clearance value. Chronic AG treatment as a low- or high-dose drug schedule produced a consistent reduction in estrone sulfate production rate (mean reductions 24 and 42%) as well as an increased estrone sulfate elimination rate constant (mean increase 30 and 69%). Urinary estriol secretion rate was consistently increased during chronic treatment (mean increase 95%) with no difference between low- and high dose drug schedules. These findings are consistent with AG being a potent enzyme inducer stimulating estrogen metabolism, and this mechanism may be an important part of AG mechanism of action by reducing estrone sulfate bioavailability.

Topics: Aminoglutethimide; Breast Neoplasms; Drug Administration Schedule; Estradiol; Estrogens; Estrone; Female; Half-Life; Humans; Menopause; Microsomes

Oestrone sulphate, the oestrogen in highest concentration in the plasma, may play a role in the induction and growth of breast cancers. By enzymolysis and radioimmunoassay, oestrone sulphate concentrations were measured in 3 biological fluids. High concentrations of the conjugate (up to 775 nmol/l) were detected in breast cyst fluids from some premenopausal women, the concentrations in blood plasma (0.91-4.45 nmol/l) being much lower. Concentrations in the plasmas from postmenopausal women with (0.23-4.63 nmol/l) or without (0.18-1.27 nmol/l) breast cancer were still lower. Oestrone sulphate concentration in cow's milk or cream (0.49-0.67 nmol/l) was also low: dietary intake in these fluids is probably of little consequence. The capacity of breast tissues for hydrolysis of oestrone sulphate was examined in two ways: In tissue slices incubated with 85 pM (3H) oestrone sulphate solution at 37 degrees C, cancers (131-412 fmol/g tissue/hr) and adipose tissues (23-132 fmol/g tissue/hr) hydrolysed significantly more sulphate than did benign tissues (1-36 fmol/g tissue/hr). In tissue homogenates incubated with 5-25 microM [3H] oestrone sulphate at 37 degrees much higher capacities for hydrolysis (nmol/g tissue/hr) were demonstrated with a Km of 2-16.5 microM: cancers (34-394) and benign tissues (9-485) had significantly higher sulphatase activities than adipose tissues (9-39). On a protein basis, however, the sulphatase activities in the 3 tissues were comparable. It is concluded that oestrone sulphate is present in breast cysts and blood plasma and that in vitro, the conjugated hormone can be hydrolysed by breast tissues. The biological significance of these findings in vivo remains to be established.

Topics: Adipose Tissue; Animals; Breast; Breast Neoplasms; Cattle; Estrone; Female; Fibrocystic Breast Disease; Humans; Hydrolysis; Menopause; Milk; Radioimmunoassay

The hydrolysis of dehydroepiandrosterone sulfate (DHAS) by human liver cells in culture and the hydrolysis of and formation of estradiol-17 beta (E2) from estrone sulfate (E1S) by human breast tumor preparations in vitro were studies in the presence and absence of danazol. In the latter tissue the effects of medroxyprogesterone acetate (MPA), trilostane, aminoglutethimide (AG) and tamoxifen were tested for comparison. Danazol at concentrations of 10(-6) - 1.4 X 10(-4) M strongly inhibited the hydrolysis of DHAS as well as the hydrolysis of and formation of E2 from E1S. With the exception of a slight inhibitory effect of trilostane upon E1S hydrolysis, the other four drugs did not inhibit the metabolism of E1S. Danazol, at concentrations corresponding to those occurring in vivo during therapy, is a potent inhibitor of steroid sulfatase activity. This may be one of the ways in which the drug affects peripheral and target tissue levels of steroid hormones.

Topics: Aminoglutethimide; Breast Neoplasms; Carcinoma; Culture Techniques; Danazol; Dehydroepiandrosterone; Dehydroepiandrosterone Sulfate; Dihydrotestosterone; Estrogen Antagonists; Estrone; Female; Humans; Medroxyprogesterone; Medroxyprogesterone Acetate; Pregnadienes; Tamoxifen

The activity of the two membrane-bound sulfatases, estrone and dehydroepiandrosterone sulfatases, are reported in human breast carcinoma tissues. In 21 tested tumors (12 from post-menopausal women and 9 from nonmenopausal women), the two sulfatases were consistently present. The apparent Km values for estrone and dehydroepiandrosterone sulfatases were, respectively, 6.8 and 14.9 microM. In terms of maximal velocity, the sulfatase activities are not correlated to the estrogen or progesterone receptor status of the tumors or to the hormonal status of the donors. It may be concluded that these two activities are not hormone dependent. Estrone sulfate, the substrate of estrone sulfatase, has been measured in plasma of postmenopausal women. The mean levels (nmol/liter) of plasma estrone sulfate were compared in post-menopausal women with (n = 51) or without (n = 39) breast cancer. For the first age group (48 to 55 years old), no statistically significant difference in these levels was observed [1.91 +/- 1.06 versus 1.50 +/- 1.04 (mean +/- t0.95 (Formula: see text) S.E.)]. For the two other age groups (56 to 65 and 66 to 80 years of age), the differences were statistically significant [1.46 +/- 0.43 versus 0.77 +/- 0.21 (p less than 0.02) and 1.77 +/- 0.53 versus 0.81 +/- 0.22 (p less than 0.01)]. The usefulness of plasma estrone 3-sulfate levels as an indicator of the real estrogen status of postmenopausal women is discussed.

Topics: Breast Neoplasms; Estradiol; Estrone; Female; Humans; Menopause; Middle Aged; Progesterone; Receptors, Estrogen; Receptors, Progesterone; Steryl-Sulfatase; Sulfatases

Estrogen sulfatase (ES) and estrogen sulfotransferase (ESFT) activities were measured in a group of primary breast tumors. The mean value of ES activities, measured in 66 breast tumor specimens, was 0.9 nmol of estrone formed from estrone sulfate/mg tissue protein per hr regardless of the hormone receptor status of the specimen. However, the average value of the ESFT activity, expressed in nmol of estradiol-3-sulfate (E2S) formed from estradiol (E2)/mg of cytosol protein per hr, was found to be significantly higher in ER +/PGR + tumors (n = 26, 0.18 +/- 0.15, means +/- SD) than in ER -/PGR - tumors (n = 31, 0.08 +/- 0.06, P less than 0.005). Normal breast tissues also contain ES and ESFT but the activities were lower than those in tumors. When fresh breast tumor tissue fragments were incubated with radioactive E2 (0.4 nM) and E2S (3 nM) separately, E2 was not sulfurylated appreciably while E2S was extensively hydrolyzed to free estrogens indicating that the combined effect of ES and ESFT in breast tumor is favored towards the hydrolysis of estrogen sulfate. These results imply that the circulating estrogen sulfate could be utilized as the precursor of active estrogen to promote the cell growth in hormone sensitive tumors.

Topics: Breast Neoplasms; Cytosol; Estradiol; Estrone; Female; Humans; Substrate Specificity; Sulfatases; Sulfotransferases; Sulfurtransferases

Estrone sulfate is quantitatively the most important estrogen in plasma. A method for its determination in human plasma is described, and the precision, accuracy, sensitivity, and specificity are defined. Free steroids were extracted from plasma with diethyl ether and steroid sulfates were isolated with use of Vlitos' reagent (methylene blue in dilute H2SO4/Na2SO4 solution). After enzymic hydrolysis, estrone was isolated by chromatography on Celite and measured by radioimmunoassay. The mean concentrations (nmol/L +/- 1 SD) of estrone sulfate were 2.51 +/- 0.90 for plasma from 13 women in follicular phase, 5.33 +/- 1.55 for 17 women in luteal phase, 0.89 +/- 0.60 for 44 postmenopausal women, and 0.96 +/- 0.43 for 24 postmenopausal women with breast cancer. Results for postmenopausal women with or without breast cancer did not differ significantly. For 13 normal men, estrone sulfate concentrations were 2.62 +/- 0.79 nmol/L, and for a group of 19 cirrhotic men the mean value was 1.43 +/- 0.95 nmol/L, significantly lower than normal.

Topics: Adult; Aged; Breast Neoplasms; Chromatography; Estrone; Female; Humans; Liver Cirrhosis; Male; Menopause; Menstruation; Middle Aged; Radioimmunoassay

Highly sensitive and specific estrogen assays are required to monitor the hormonal effects of surgical adrenalectomy or pharmacologic estrogen suppression in postmenopausal women with breast carcinoma. Because the levels of plasma estrone-sulfate are 10-fold higher than its unconjugated counterpart, we developed a radioimmunoassay for estrone-sulfate to quantitate the minimal estrogen concentrations expected under conditions of endocrine gland ablation. After establishing normal ranges, we compared plasma estrone- sulfate levels and urinary conjugated estrone basally and after surgical adrenalectomy or aminoglutethimide (estrogen suppression) therapy in 23 postmenopausal women with breast carcinoma. In response to either therapy, the plasma levels of estrone-sulfate fell by 63.5-79.2% (p less than .01) and conjugated urinary estrone by 85-94.5% (p less than .01) in all study days over a 12-week period. Correlation analyses yielded r values of 0.77-0.94 between conjugated plasma and urinary estrone concentrations in the surgical adrenalectomy and aminoglutethimide-treated groups, respectively. No significant differences in estrone-sulfate levels were observed when comparing spontaneously menopausal and surgically castrate patients.

Topics: Adrenalectomy; Adult; Aged; Aminoglutethimide; Breast Neoplasms; Estrogens, Conjugated (USP); Estrone; Female; Humans; Menopause; Middle Aged; Radioimmunoassay; Reference Values

Topics: Animals; Breast Neoplasms; Castration; Cell Nucleus; Cytosol; Estradiol; Estrogens, Conjugated (USP); Estrone; Female; Humans; Mammary Neoplasms, Experimental; Mice; Mice, Inbred C3H; Radioimmunoassay; Receptors, Estrogen

Topics: Breast; Breast Neoplasms; Estrogens; Estrone; Humans; Neoplasms