Differences between estrogen- and antiestrogen-estrogen receptor complexes from human breast tumors identified with an antibody raised against the estrogen receptor.

Radiolabeled estrogens 17 beta-[3H]estradiol and diethylstilbestrol ( [3H]DES) and the antiestrogen [3H]monohydroxytamoxifen ( [3H]MHT) all bind with high affinity to the extranuclear estrogen receptor (ER) from the MCF-7 human breast tumor cell line (Kd = 3 X 10(-10), 2 X 10(-10), and 0.63 X 10(-10) M, respectively). A polyclonal antibody raised in a goat to the calf nuclear ER selectively decreased the binding affinity and number of binding sites for 17 beta-[3H]estradiol, but did not appear to affect these binding parameters for [3H]MHT. In the presence of goat antibody, the binding of the nonsteroidal estrogen DES was so perturbed that it was not possible to quantitate the decreased number of binding sites or affinity of this compound as assessed by Scatchard saturation analysis. These results were confirmed in human breast tumor cytosols by sucrose density gradient analysis. The binding of 17 beta-[3H]-estradiol and [3H]DES to the ER was significantly reduced by preincubation with the polyclonal antibody, whereas the binding of [3H]MHT was reduced only when the tumor cytosol was preincubated with a very high concentration of antibody. At these concentrations of antibody, the binding of 17 beta-[3H]estradiol and [3H]DES to the receptor was prevented completely. In contrast, when the antibody was added to the tumor cytosol after the 3H-ligand had bound to the receptor, the binding properties of all 3H-ligands were unaffected. The [3H]MHT-ER antibody complex consistently sedimented as a higher-molecular-weight complex on sucrose density gradients than did the corresponding estrogenic complexes. The decrease in the affinity of estrogenic ligands can be explained in part by an increase in the dissociation rate at 4 degrees of these compounds from the ER. The dissociation rate of MHT was unaffected by the goat antibody. These results imply that there are important differences in the binding of antiestrogen and estrogens to the tumor cytosol ER. A ligand-binding model is proposed that may aid in the understanding of antiestrogen action.

Rat uterine growth and induction of progesterone receptor without estrogen receptor translocation.

The rat uterus responds to estradiol (E2) and E2 benzoate stimulation with an increase in progesterone receptor production and with growth. These responses were also elicited to varying degrees by a series of estrogenic (ICI 77,949 and ICI 47,699) and antiestrogenic triphenylethylene derivatives [tamoxifen (TAM), 4-hydroxy-TAM (4-OH-TAM), and 4-CH3-TAM]. These compounds have a range of affinities for the estrogen receptor (ER) and are able to compete with [3H]E2 binding in the uterus in vivo. Within 1-2 h of a sc injection of high affinity ligands (E2, E2B, and 4-OH-TAM), there was decrease in cytosol ER. This decrease was also observed with TAM, which is metabolized to 4-OH-TAM in vivo. In contrast, there was no decrease in cytosolic ER in animals treated with low affinity compounds (ICI 77,949, ICI 47,699, and 4-CH3-TAM) at any time before the onset of an estrogenic response. Furthermore, the nuclear ER increased after administration of a high affinity ligand (E2), as measured by exchange assay, but no increase in nuclear ER was observed after administration of low affinity ligands (ICI 77,949 and 4-CH3-TAM), although estrogenic responses were produced. From these data we have suggested a functional model to explain ER-mediated events in the rat uterus that supports the recent proposal that unoccupied ER is located in the nuclear compartment. In this model, the majority of unoccupied ER may reside in the nucleus in vivo; however, when the cells are disrupted in vitro, the unoccupied receptor or dissociation of low affinity ligand-ER complex causes unoccupied receptor to fall out of the nucleus and be incorporated into the cytosolic fraction. The high affinity ligand-ER complexes are retained in the nucleus. This would suggest that the apparent translocation of the ER from the cytoplasm to the nucleus may be an artifact. The data may reflect differential extraction of unoccupied receptors from the nucleus rather than transfer of receptor complexes to the nucleus.

Nuclear [3H]4-hydroxytamoxifen (4-OHTAM)- and [3H]estradiol (E2)-estrogen receptor complexes in the MCF-7 breast cancer and GH3 pituitary tumor cell lines.

Nuclear [3H]4-OHTAM-ER complexes extracted by 0.6 M KCl from the MCF-7 human breast cancer and the GH3 rat pituitary tumor cell lines, sedimented as a 5S form on sucrose gradients after 1 to 24 h exposure to ligand (20 nM). The nuclear [3H]4-OHTAM-ER from MCF-7 cells increased from 2 +/- 0.2 pmoles/mg DNA at 1 h to approximately 4 +/- 0.1 pmoles/mg DNA at 6 and 24 h. In the GH3 cells the nuclear binding of [3H]4-OHTAM increased rapidly, and there was no significant difference in the receptor levels at 1 and 6 h (10 +/- 1.3 and 8.9 +/- 1.1 pmoles/mg DNA, respectively). At 24 h there was a decrease in [3H]4-OHTAM-ER levels (7.0 +/- 0.2 pmoles/mg DNA); however, this was due primarily to an increase in DNA synthesis, which occurred in these cells by 24 h. It appears that in both cell lines there is no processing of nuclear [3H]4-OHTAM-ER, and it is not associated with changes in sedimentation coefficient of the complex. When both cell lines were incubated with [3H]E2 (20 nM), processing of the nuclear [3H]E2-ER occurred over 6 h. In the MCF-7 cells there was a decrease in receptor content within 6 h from 3.2 +/- 0.2 to 0.9 +/- 0.2 pmoles/mg DNA. The nuclear [3H]E2-ER in the GH3 cells decreased from 7.3 +/- 0.5 to 2.8 +/- 0.3 pmoles/mg DNA. Although these cell lines appeared to process the [3H]E2-ER complex, the nuclear forms of [3H]E2-ER were different.(ABSTRACT TRUNCATED AT 250 WORDS)

An immobilized antiestrogen binds a specific uterine protein in addition to estrogen receptor proteins.

An antiestrogen affinity resin was synthesized by conjugating LY117018, a benzothiophene -derived antiestrogen, to epoxy-activated agarose. This affinity resin bound the Mr = 50 000 and 65 000 estrogen receptor proteins of rabbit uterine cytosol; in addition, it retained a protein from the cytosols of both rat and rabbit uteri that exhibited an ability to interact specifically with LY117018. The possibility that the LY117018 binding protein, which is distinct from estrogen receptors, may play a role in the antiestrogenic actions of LY117018 is discussed.

Effects of simvastatin and pravastatin on gonadal function in male hypercholesterolemic patients.

Inhibition of cholesterol biosynthesis by hydroxymethyl glutaryl coenzyme A (HMG-CoA) reductase inhibitors could, in theory, adversely affect male gonadal function because cholesterol is a precursor of steroid hormones. The objective of this randomized double-blind trial was to compare the effects of simvastatin, pravastatin, and placebo on gonadal testosterone production and spermatogenesis. After a 6-week placebo and lipid-lowering diet run-in period, 159 male patients aged 21 to 55 years with type IIa or IIb hypercholesterolemia, low-density lipoprotein (LDL) cholesterol between 145 and 240 mg/dL, and normal basal levels of testosterone were randomly assigned to treatment with simvastatin 20 mg (n = 40), simvastatin 40 mg (n = 41), pravastatin 40 mg (n = 39), or placebo (n = 39) once daily. After 24 weeks of treatment, mean total cholesterol levels were decreased 24% to 27% and mean LDL cholesterol was decreased 30% to 34% in the 3 active-treatment groups (P < .001 for all comparisons to placebo). At 24 weeks, there were no statistically significant differences between the placebo group and any of the active-treatment groups for the change from baseline in testosterone, human chorionic gonadotropin (hCG)stimulated testosterone, free testosterone index, follicle-stimulating hormone (FSH), luteinizing hormone (LH), or sex hormone-binding globulin (SHBG). Moreover, there were no statistically significant differences at week 12 or week 24 for the change from baseline in sperm concentration, ejaculate volume, or sperm motility for any active treatment relative to placebo. Both simvastatin and pravastatin were well tolerated. In summary, we found no evidence for clinically meaningful effects of simvastatin or pravastatin on gonadal testosterone production, testosterone reserve, or multiple parameters of semen quality.

Effects of simvastatin versus gemfibrozil on lipids and glucose control in patients with non-insulin-dependent diabetes mellitus. NIDDM Study Group.

The objective of this study was to compare the lipid-altering efficacy and safety of simvastatin with that of gemfibrozil in hypercholesterolemic patients with non-insulin-dependent diabetes mellitus (NIDDM). The study was a 24-week, double-blind, randomized, multicenter trial conducted at clinics and hospitals in the United States, Austria, Germany, Brazil, and New Zealand. The study population included 168 men and women aged 34 to 78 years with NIDDM and primary hypercholesterolemia (low-density lipoprotein cholesterol [LDL-C] level at screening was > or = 4.9 mmol/L with no other risk factor or > or = 4.1 mmol/L with one or more other risk factors). All patients had been under moderate-to-good diabetic control (hemoglobin A1c [HbA1c] < or = 10.0%) for at least 6 months with diet alone, oral hypoglycemic agents, or insulin therapy. Patients meeting eligibility criteria were randomized to receive either simvastatin 10 mg (titrated up to 40 mg to achieve an LDL-C level < 3.4 mmol/L) once in the evening or gemfibrozil 600 mg twice daily. There were 81 patients in the simvastatin group and 87 patients in the gemfibrozil group. After 17 weeks of treatment, simvastatin significantly reduced levels of total cholesterol, LDL-C, and very-low-density lipoprotein cholesterol (VLDL-C) by approximately 25%, 33%, and 20%, respectively (P < or = 0.001), and triglycerides by about 9% (P < or = 0.05). The drug increased high-density lipoprotein cholesterol (HDL-C) levels by about 6% (P < 0.01). Gemfibrozil significantly reduced total cholesterol, VLDL-C, and triglyceride levels by approximately 8%, 38%, and 27%, respectively (P < 0.001); it significantly increased HDL-C values by about 12% (P < 0.001). Gemfibrozil lowered LDL-C levels by 4% but not significantly. The decreases in total cholesterol and LDL-C were significantly greater (P < 0.001) in the simvastatin group, and decreases in VLDL-C and triglycerides were significantly greater in the gemfibrozil group (P < 0.01). The changes in HDL-C were not significantly different between groups. LDL-C values of < 3.4 mmol/L were achieved in 60% of the simvastatin patients and 14% of the gemfibrozil patients. There were no significant between-group differences in fasting serum glucose or HbA1c at any time point. Glycemic profiles (performed at baseline and after 17 weeks of treatment) and glucose area under the curve (at baseline and after 17 weeks of treatment) were not significantly different between treatment groups. Both drugs were generally well tolerated.(ABSTRACT TRUNCATED AT 400 WORDS)

Lipid-altering efficacy and safety of simvastatin 80 mg/day: long-term experience in a large group of patients with hypercholesterolemia. World Wide Expanded Dose Simvastatin Study Group.

BACKGROUND: Elevated levels of low-density lipoprotein (LDL) cholesterol promote the development of atherosclerosis and coronary heart disease. HYPOTHESIS: Simvastatin 80 mg/day will be more effective than simvastatin 40 mg/day at reducing LDL cholesterol and will be well tolerated. METHODS: Two similar, randomized, multicenter, controlled, double-blind, parallel-group, 48-week studies were performed to evaluate the long-term lipid-altering efficacy and safety of simvastatin 80 mg/day in patients with hypercholesterolemia. One study conducted in the US enrolled patients meeting the National Cholesterol Education Program (NCEP) LDL cholesterol criteria for pharmacologic treatment. In the other multinational study, patients with LDL cholesterol levels > or = 4.2 mmol/l were enrolled. At 20 centers in the US and 19 countries world-wide, 1,105 hypercholesterolemic patients, while on a lipid-lowering diet, were randomly assigned at a ratio of 2:3 to receive simvastatin 40 mg (n = 436) or 80 mg (n = 669) once daily for 24 weeks. Those patients completing an initial 24-week base study were enrolled in a 24-week blinded extension. Patients who had started on the 80 mg dose in the base study continued on the same dose in the extension, while those who had started on the 40 mg dose were rerandomized at a 1:1 ratio to simvastatin 40 or 80 mg in the extension. RESULTS: There was a significant advantage in the LDL cholesterol-lowering effect of the 80 mg dose compared with that of the 40 mg dose, which was maintained over the 48 weeks of treatment. The mean percentage reductions (95% confidence intervals) from baseline in LDL cholesterol for the 40 and 80 mg groups were 41% (42, 39) and 47% (48, 46), respectively, for the 24-week base study, and 41% (43, 39) and 46% (47, 45), respectively, after 48 weeks of treatment (p < 0.001 between groups). Larger reductions in total cholesterol and triglycerides were also observed with the 80 mg dose compared with the 40 mg dose at Weeks 24 and 48. Both doses were well tolerated, with close to 95% of patients enrolled completing the entire 48 weeks of treatment. Myopathy (muscle symptoms plus creatine kinase increase > 10 fold upper limit of normal) and clinically significant hepatic transaminase increases (> 3 times the upper limit of normal) occurred infrequently with both doses. There was no significant difference between the groups in the number of patients with such increases, although there were more cases for both with the 80 mg dose. CONCLUSIONS: Compared with the 40 mg dose, simvastatin 80 mg produced greater reductions in LDL cholesterol, total cholesterol, and triglycerides. Both doses were well tolerated.

The effect of sex steroids on the degradation of LRH by hypothalamic homogenates.

Extract of hypothalami was prepared which contained peptidase capable of degrading LRH. The degradation of LRH by this extract either alone or under the influence of oestrogens, androgens and cholesterol, when added to the extract was measured. Oestrone, oestradiol and oestriol (1 pg to 100 pg) stimulated mean peptidase activity significantly (P less than 0.001) in a dose-dependent manner. Testosterone (0.1 ng to 10 ng) also caused a dose-dependent increase in degradation of LRH, the two highest doses used significantly increasing the mean activity (P less than 0.001). Only the highest dose of androstenedione (10 ng) or dehydroepiandrosterone (10 ng) caused a significant increase of the mean LRH degradation (P less than 0.05). Neither cholesterol nor dihydrotestosterone increased peptidase activity when added to the extract. It is suggested that it is possible that these peptidase enzymes could occupy a role in the negative feedback of steroids on the hypothalamus.

Distribution of interdivisional times in proliferating and differentiating Friend murine erythroleukaemia cells.

The interdivisional times of Friend murine erythroleukaemia cells which are growing continuously, or during terminal erythroid differentiation after exposure to dimethyl sulphoxide (DMSO), were determined by time lapse video photography. The median interdivisional times were found to increase from 11.75 hr before exposure to DMSO, to 24.0 hr at 72 hr after exposure. This increase in median interdivisional time was accompanied by an increase in heterogeneity of interdivisional times (%CV = 8.5----40.8), by an increase in the similarity of sister interdivisional times (ryy = 0.622----0.925), and by a decrease in the fraction of cells observed to divide (F = 1.0----0.807). Cells exposed to DMSO for 72 hr can be induced to divide at least once with nearly normal interdivisional times, if they are resuspended at a tenfold higher cell concentration. Computer simulations of cell cycle regulation, based on the opposing reactions model of Murphy, generate interdivisional time distributions which resemble the experimental data better than the single transition probability model of Smith and Martin.

The inhibition of prolactin synthesis in GH3 rat pituitary tumor cells by monohydroxytamoxifen is associated with changes in the properties of the estrogen receptor.

E2 (1 nM) stimulated the synthesis of PRL in GH3 cells. OH TAM (100 nM) did not affect basal PRL synthesis, but completely inhibited the increase produced by 1 nM E2. [3H]E2 and [3H]OH TAM both bound to the cytosolic 8S ER and these were split into 4S subunits on sucrose gradients containing 0.4 M KCl. By comparison, ER complexes extracted from nuclei of GH3 cells cultured in media containing [3H]E2 or [3H]OH TAM both sedimented at 5S on sucrose gradients containing 0.4 M KCl. Both 4S and 5S ER complexes were recognized by the monoclonal antibody D547 which increased their sedimentation coefficients to 8-9S. In contrast, a polyclonal antibody raised to calf uterine ER in the goat, interacted with the cytosolic ER so that the binding of [3H]E2 was inhibited but the binding of [3]OH TAM was only slightly reduced. A molecular model is proposed to describe the binding of E2 and OH TAM to the ER that might contribute to an understanding of estrogen and antiestrogen action.

Binding of [3H] monohydroxytamoxifen in ovarian carcinoma.

A monoclonal antibody (D-547) against human breast cancer oestrogen receptor was used to demonstrate that the oestrogen receptor in ovarian epithelial carcinomata binds [3H]monohydroxytamoxifen. This binding was observed in sedimentation velocity analyses of both cytosol and nuclear compartments. Binding of [3H]monohydroxytamoxifen to the antibody-recognized moiety could be inhibited by diethylstilboestrol or oestradiol, but not by androgen, progestin or corticoid, indicating oestrogen specificity for the binding site. The sedimentation coefficient of the antibody-recognized [3H]monohydroxytamoxifen binding moiety was similar to that when 16 alpha-[125I]iodo-oestradiol was used as the ligand.

Eimeria tenella: quantitative in vitro and in vivo studies on the effects of mouse polyclonal and monoclonal antibodies on sporozoites.

Murine, polyclonal and monoclonal antibodies, raised against sporozoites of Eimeria tenella, were tested for their ability to neutralize sporozoite infectivity in vitro and in vivo. Neutralization was effected via three mechanisms. Firstly, sporozoites fixed complement, at low titres, and lysis occurred by the alternative pathway of complement activation. Secondly, in the absence of complement activity, the murine heat-inactivated, hyperimmune antiserum neutralized sporozoites at relatively low titres. At high titres, even though sporozoites were agglutinated, neither the heat-inactivated hyperimmune antiserum nor the monoclonal antibody neutralized sporozoites. Finally, in the presence of complement and specific antibodies, at titres which by themselves would not neutralize sporozoites, neutralization was effected due to lysis via the classical pathway of complement activation.

Interaction of [3H] estradiol - and [3H] monohydroxytamoxifen-estrogen receptor complexes with a monoclonal antibody.

The aim of this study was to compare and contrast the interaction of estrogen [( 3H]17 beta-estradiol)- or antiestrogen [( 3H]monohydroxytamoxifen)-receptor complexes from human breast tumor cytosols with monoclonal antibodies raised to the human breast tumor estrogen receptor. Breast tumor cytosols containing estrogen receptor which sedimented as radiolabeled peaks in either the 8S, 8S and 4S, or 4S regions of sucrose density gradients, interacted with the monoclonal antibody D547 to produce a broad 9-10S peak, a broad 8S-10S peak, or a more discrete 8S peak, respectively. On high salt (0.4M KC1) sucrose density gradients the 4S ligand-receptor complex plus antibody produced a binding peak at approximately the 8S region of the gradient. These sedimentation studies with the monoclonal antibody D547, and similar studies with the monoclonal antibody D58, could detect no differences in the cytosolic estrogen receptor whether complexed with [3H]estradiol or with [3H]monohydroxytamoxifen. These observations were confirmed by Scatchard equilibrium saturation analysis and sucrose density gradient analysis of cytosols from the MCF-7 human breast cancer cell line. The antibody D547 interacted with 8S ER from these cytosols to produce a broad 8S-10S peak, but the antibody produced no change in the affinity or number of binding sites present in these cytosols. It seems, therefore, that the antigenic determinants recognized by these particular antibodies on the breast tumor cytosolic receptor are not significantly altered by the binding of either an estrogen or an antiestrogen to the receptor.

Interferon-induced growth modulation: low dose maintenance of the antiproliferative response.

Treatment of the Burkitt's lymphoma-derived Daudi cell line with human beta interferon (HuIFN-beta) results in a dose-dependent antiproliferative response. We have defined three phases including: (1) initiation, (2) maintenance, and (3) termination of the antiproliferative state. Each phase is characterized by specific growth modulatory properties. Initiation of the antiproliferative state with a single interferon dose requires 200 International Reference Units (IRU) per ml, depending on such factors including cell density, serum content in the medium and the length of IFN exposure. Initiation of the IFN response occurred within a 4 h incubation period. Even following this short exposure, the vast majority of cells would be sequestered in the G0/G1 cell cycle compartment. As measured by cytofluorimetry there was a 16-20 h delay in the initiation of the antiproliferative response. The antiproliferative response, as measured by changes in the distribution of cells in the cell cycle, was maximal at 24 h after treatment. This delay was equal to the doubling time of the Daudi cell. The antiproliferative response initiated by 200 IRU/ml of IFN was reversible if the IFN was removed and not replenished. Cells showed renewed growth approximately 40 h after treatment. The antiproliferative state could be maintained by additional interferon, but, even after such treatment, the antiproliferative state decayed in a dose-dependent fashion. This decay was proportional to the decrease in the biological activity of the interferon molecule itself. Finally, we showed that the antiproliferative state could be maintained by using only 40 IRU/ml. These cells were maintained in the antiproliferative state for an extended period of time.

Influence of age and gender on the plasma profiles of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitory activity following multiple doses of lovastatin and simvastatin.

The effects of age and of gender on the plasma profiles of HMG-CoA reductase inhibitors following separate once-a-day dosage regimens (17 days) of lovastatin (80 mg/day) and simvastatin (40 mg/day) were studied in hypercholesterolemic patients. In general, plasma concentrations of active and total HMG-CoA reductase inhibitors were higher in elderly individuals (age, 70 to 78 years) and in females for both drugs. However, the Tmax of these inhibitors was not significantly affected by either age or gender. Following the last dose of lovastatin, the mean steady-stage plasma concentrations of total and active HMG-CoA reductase inhibitors were 30-60% higher in the elderly than in young individuals (age, 19 to 30 years). Also, the mean plasma concentrations were 20-50% higher in female than in male patients. Similarly, following the last dose of simvastatin, the mean plasma concentrations of HMG-CoA reductase inhibitors were 40-60% higher in the elderly than in young patients and were 20-50% higher in female than in male patients. These age- and gender-related differences do not appear to be large enough to warrant modification of dosage regimens, because plasma concentrations of these inhibitors are not necessarily indicative of efficacy and the therapeutic windows for lovastatin and simvastatin are broad.

Lipid-altering efficacy and safety of simvastatin 80 mg/day: worldwide long-term experience in patients with hypercholesterolemia.

BACKGROUND AND AIM: Clinical data suggesting that larger decreases in low density lipoprotein cholesterol (LDL-C) result in greater reductions in coronary heart disease events have led to the establishment of aggressive LDL-C targets for the treatment of hypercholesterolemia. In view of this, the efficacy and safety of a new maximum dose of simvastatin, 80 mg, were evaluated in 9 studies involving 2819 hypercholesterolemic patients. This report focuses on the combined results from the 4 main or Pivotal studies in which a total of 1936 patients received simvastatin 40 or 80 mg for 36 to 48 weeks. METHODS AND RESULTS: The Pivotal studies had similar randomized, multicenter, controlled, double-blind, parallel-group designs. Their combined results demonstrated a significant advantage in the LDL-C-lowering effect for the 80 mg dose. At week 24, the mean percentage reductions (95% confidence intervals) from baseline in LDL-C for the 40 and 80 mg groups were -39.8% (-40.9, -38.7) and -45.7% (-46.5, -45.0) respectively (p < 0.001, between groups), and larger reductions in total cholesterol and triglycerides were also observed in the 80 mg group. Both doses were well tolerated. No new or unexpected adverse events were observed and the overall clinical event profiles were similar in the two groups. Clinically significant hepatic transaminase increases (> 3 times the upper limit of normal/ULN) and myopathy (muscle symptoms plus creatine kinase increase > 10 times ULN) occurred infrequently with both doses. Simvastatin 80 mg had a comparable efficacy and safety profile in women and men as well as in non-elderly and elderly patients. CONCLUSIONS: Simvastatin 80 mg provides additional LDL-C and triglyceride reductions compared to the 40 mg dose and has an excellent safety and tolerability profile.