Studies on estrogen and progesterone receptors in human breast cancer by sucrose gradient centrifugation (author's transl)]

Steroid receptor assays in advanced or recurrent breast cancer are now recognized as a method for predicting therapeutic response to endocrine therapy. ER (estrogen receptor) and PgR (progesterone receptor) were measured by sucrose gradient centrifugation. Breast cancer, benign mammary tumors, and normal mammary tissue were examined. Following extensive laboratory procedures, several results were observed. The specific binding of ER was observed at the 8S as was the binding of PgR. 45% of human breast cancers were ER(+) and about 20% were PgR (+), with the positive rate of PgR lower than that of ER. All normal mammary tissues were ER (-) and with the benign mammary tumors, 1 of 10 fibroadenomas and 1 of 3 giant fibroadenomas was ER (+). Positive rates of ER and PgR were similar between premenopausal and postmenopausal females and across blood types A, B, and O. ER and PgR were negative in AB blood. The occurrence of ER in 10 cases of primary tumor and in metastatic or recurrent lesions was almost identical and binding sites were at almost the same level. Where both ER and PgR were measured in 39 cases, the 8 cases of PgR (+) showed ER (+) and there was a close relationship between the 2. With ER (+), papillotubular carcinomas tended to be lower than other histological types; in binding sites of ER, medullary tubular carcinoma occurred more frequently than schirrous carcinoma. Medullary tubular carcinoma occurred more often in the PgR. In 21 cases where the clinical response to endocrine therapy and the occurrence of ER were measured, 50% (6) of ER (+) and 25% of ER (+) or (-) displayed a response with 5 ER (-) cases showing no response. Endocrine therapy in 11 of 39 above mentioned cases was carried out with cases of ER (+) and PgR (+) responding better than those of ER (+) only. (Author's modified)     

The ontogeny of mouse mammary gland responsiveness to ovarian steroid hormones

An investigation was carried out to define the ontogeny of normal mouse mammary gland responsiveness to the proliferative effects of estrogen (E) and/or progesterone (P). Since hormone receptors for both estrogen (ER) and progesterone (PgR) are present in both epithelial and stromal cells, we have investigated how the effects of E and P are related to the presence of receptor activity in the epithelium and stroma. Intact or ovariectomized mice, between 3 days and 10 weeks of age, were used to study the effects of E and/or P on DNA synthesis, as determined by DNA histoautoradiography; the cellular distribution of ER and PgR was investigated by steroid autoradiography. The results indicate that the mammary gland sequentially acquires the ability to respond to the stimulatory effects of E and/or P. In the early postnatal period (3-14 days) neither hormone was effective. Both epithelial and stromal cells first became responsive to E at 3-4 weeks of age. Estrogen receptors were first detected in stromal cells at 5 days of age and in epithelial cells at 2 weeks of age. Thus, the acquisition of estrogen responsiveness did not appear to be tightly coupled to the presence of ER in either epithelial or stromal cells. In contrast, responsiveness to P was acquired significantly later, at 7 weeks of age, and was closely linked to the presence of E-inducible PgR in epithelial cells. P caused a highly synergistic effect on epithelial cell DNA synthesis when combined with E, providing further support for the concept that the major proliferative effect of P is mediated via E-inducible PgR. PgR were also present in stromal cells, but the proliferative effect of P in that cell type was not correlated with the presence of PgR.     

Steroid hormone receptors in three human gastric cancer cell lines

Steroid hormone receptors in three human gastric adenocarcinoma cell lines and their transplanted tumors (except nontumorigenic KATO-III) in nude mice were determined by dextran-coated charcoal assay. Progesterone receptors (PgR) were found in all cell lines, transplanted NUGC-3, and AZ 521 tumors. Estrogen receptors (ER) were found in KATO-III cells, transplanted NUGC-3, and AZ 521 tumors, whereas glucocorticoid receptors (GR) were found only in NUGC-3 tumor and no androgen receptor was found in any cell lines or transplanted tumors. Since NUGC-3 cells had ER, PgR, and GR, it was used for the study of the effects of steroid hormones on growth. The results showed the cell cycle phase distributions and growth rate of transplanted tumors were similar in hormone-treated and nontreated groups. The persistent expression of PgR in gastric cancer cell lines and tumors, and the slight increase of tumor volumes in the progesterone-treated group suggests that progesterone and its receptors may be important in the pathogenesis of gastric cancer, but their biological function remains to be elucidated.This study was supported by a grant from National Science Council of the Republic of China (NSC 81-0412-B075-48).     

GnRH receptors in human breast cancer and its contiguous not-involved breast tissue

The present study was undertaken to evaluate the presence of GnRH receptors (GnRH-R) in breast cancer and not-involved breast tissue, and the relationships between GnRH-R and receptors for estrogen (ER) and progesterone (PgR) in the same tissues. Utilizing a tritiated natural GnRH in order to assay the native receptor binding we analyzed the level of binding sites for GnRH in membranes derived from 90 breast tumors and in 40 cases from neighboring, not-involved breast tissue. GnRH-R was found both in cancer and normal tissues. The prevalence for GnRH-R was higher in tumor than in not-tumor tissue (45% vs 39%, respectively), but the overall levels were not significantly different (15.9+/-24 fmol/mg protein vs 18.2+/-39 fmol/mg protein, respectively). The only statistically different content of GnRH-R we found concerned PgR negative vs PgR positive tumor tissues (mean content: 23 vs 11 fmol/mg protein, respectively in PgR- and PgR+ tumors, p=0.03 by t test); furthermore the proportion of GnRH-R positive cases in the tumor resulted significantly higher in premenopausal patients vs postmenopausal (56% vs 32%, by Chi square test, p<0.05). The GnRH receptors status of primary tumor and contiguous not-involved breast tissue resulted associated (overall agreement: 63%, p<0.05) but no specific steroid patterns for GnRH-R positivity was observed.     

Breast cancer patients with estrogen receptor-negative/progesterone receptor-positive tumors: being younger and getting less benefit from adjuvant tamoxifen treatment

Purpose  Most breast cancer patients with estrogen receptor-negative/progesterone receptor-positive (ER−/PgR+) tumors are premenopausal cases, with few alternatives of adjuvant endocrine therapy but tamoxifen (TAM). The efficacy of adjuvant TAM on ER−/PgR+ patients is still controversial. In this study, we evaluated the efficacy of adjuvant TAM on patients with ER−/PgR+ tumors. Methods  Among all 1,836 consecutive patients with operable primary breast cancer, 798 cases were with ER+/PgR+ tumors and 205 with ER−/PgR+ tumors. By sub-grouping the patients according to ER/PR phenotypes and whether the patients had been treated with adjuvant TAM therapy or not, we investigated the differences of survivals between groups. Results  Patients with ER−/PgR+ tumors were younger than those with ER+/PgR+ tumors (P = 0.021), and were mainly premenopausal (P = 0.013). ER−/PgR+ patients were related to more involved lymph nodes and later stage. In the absence of TAM treatment, ER+/PgR+ group had a similar survival to ER−/PgR+ group in terms of 5-year disease-free survival (DFS), as well as overall survival (OS). After TAM treatment, both groups had increased survival rates comparing with the baseline of non-TAM-treated groups. Moreover, significant survival differences were then observed between TAM-treated ER+/PgR+ group and TAM-treated ER−/PgR+ group either in DFS (P = 0.016) or OS (P = 0.007). Of the TAM-treated patients, by sub-dividing the chemotherapy-treated population into CMF (cyclophosphamide, methotrexate and 5-fluorouracil) group and CA(E)F (cyclophosphamide, doxorubicin/epirubicin and 5-fluorouracil) group, we found that ER−/PgR+ group got more benefits from CMF regimen than from CA(E)F. Subpopulation treatment effect pattern plot (STEPP) analysis showed that the ER−/PgR+ group had an obvious worse survival than ER+/PgR+ group in younger patients (<55 years). Axillary lymph nodes involvement was the only independent prognostic factor for ER−/PgR+ group. Conclusions  Our results indicate that patients with ER−/PgR+ tumors are mainly premenopausal and young. Although patients with ER−/PgR+ tumors are generally considered as candidates for endocrine therapy clinically, the ER−/PgR+ group gains less benefits from adjuvant TAM treatment than ER+/PgR+ group. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Yu Ke-da and Di Gen-hong have contributed equally to this work.     

Relationship between peroxidase activity and steroid receptors in human mammary tumors

The interrelationships between levels of estradiol receptors (ER) and estrogen-dependent proteins, peroxidase and progesterone receptors (PgR) were examined in 54 histologically proven primary breast tumors in Indian women. ER and PgR were determined by the agar gel electrophoresis and dextran coated charcoal methods, respectively. Peroxidase activity (PA) was estimated by the guaiacol method. Our results showed a lack of correlation between ER and PA as well as between concentrations of PgR and PA in the tumors. It was concluded from this preliminary investigation that, in addition to ER and PgR, estimation of PA does not contribute significantly to more accurate assessment of hormone dependence of human breast tumors.     

Study of the role of steroid receptors in human breast cancer

Cytoplasmic estrogen receptors (ER) were studied in 200 female patients with primary breast cancer. Both ER and progesterone receptors (PgR) were studied in 38 patients. Of the 200 tumors, 55% were estrogen receptor-positive, of the 38 tumors, 34.2% were progesterone receptor-positive. The level of steroid receptors was compared with some parameters characterizing the host and the tumor. It was found that the level of ER correlated with the age factors and the menstrual status. The level of ER was higher in women with adrenal or involutive pathogenetic forms of breast cancer and in women with great body weight. There was not found any relation between the level of estrogen receptors and the stage of menstrual cycle as well as between the level of estrogen receptors and the content of sex chromatin in the tumors.     

Estrogen and progesterone receptors in the human vagina

Estrogen (E) and progesterone (Pg) receptor (R) levels were determined in the human vagina in relation to menopausal status, day of ovarian cycle and pregnancy. The results obtained confirmed that the human vagina contains ER and, in addition, demonstrated for the first time the presence of PgR in this organ in humans. In cycling women, ER and PgR did not vary significantly during the ovarian cycle; however low (less than or equal to 10 fmoles/mg cytosol protein) concentrations of PgR were more frequently (6 out of 8 cases) detected during the secretory phase. No substantial difference was seen in ER and PgR values between anterior and posterior wall of the vagina. In postmenopausal patients the levels of ER (range: 10-83 fmoles/mg) were similar to those found in premenopause (range: 12-78 fmoles/mg). As regards PgR, the majority (14 out of 20) of vaginae were devoid of PgR, 4 had a very low (less than or equal to 6 fmoles/mg) PgR content and only 2 cases had a PgR level higher than 10 fmol/mg cytosol protein. In pregnant patients (6th to 8th week) ER were found in all vaginae, while PgR were present only in some cases (3 out of 8). It was concluded that the behavior of ER in the human vagina seems different from that in the human endometrium, since ER levels do not vary in relation to changes in the concentrations of sexual hormones in the circulation. On the contrary, PgR levels appear to depend on blood estradiol and progesterone concentration, as in other target tissues.     

Liver expression of steroid hormones and Apolipoprotein D receptors in hepatocellular carcinoma

AIM: To evaluate the tissular expression of Androgen (A), Estrogen (E) and Progesterone (Pg) receptors, and Apolipoprotein D (ApoD), in liver tumors from resected hepatocellular carcinoma (HCC) cases in order to assess their possible relationship to prognosis. METHODS: We performed an immunohistochemical study using tissue microarrays (containing more than 260 cancer specimens, from 31 HCC patients and controls) to determine the presence of specif ic antibodies against AR, ER, PgR and ApoD, correlating their findings with several clinico-pathological and biological variables. The staining results were categorized using a semi-quantitive score based on their intensity, and the percentage of immunostained cells was measured. RESULTS: A total of 21 liver tumors (67.7%) were positive for AR; 16 (51.6%) for ER; 26 (83.9%) for PgR and 12 (38.7%) stained for ApoD. We have found a wide variability in the immunostaining score values for each protein, with a median (range) of 11.5 (11.5-229.5) for AR; 11.1 (8.5-65) for ER; 14.2 (4-61) for PgR; and 37.7 (13.8-81.1) for ApoD. A history of heavy ethanol consumption, correlated positively with AR and PgR and negatively with ER status. HCV chronic infection also correlated positively with AR and PgR status. However, the presence of ApoD immunostaining did not correlate with any of these variables. Tumors with a positive immuno-staining for PgR showed a better prognosis. CONCLUSION: Our results indicate a moderate clinical value of the steroid receptor status in HCC, emphasizing the need to perform further studies in order to evaluate the possible role of new hormonal-based therapies.     

Role of carbonic anhydrase IX expression in prediction of the efficacy and outcome of primary epirubicin/tamoxifen therapy for breast cancer

The purpose of this study is to investigate the role of carbonic anhydrase IX (CAIX) expression in predicting the response to epirubicin and disease-free survival (DFS) in breast cancer patients enrolled in a single institution trial of primary anthracycline and tamoxifen therapy. CAIX expression was assessed in 183 patients with T2-4 N0-1 breast cancer enrolled in a randomized trial comparing four cycles of single agent epirubicin versus epirubicin+tamoxifen as primary systemic treatment. All patients received postoperatively four cycles of the four weekly i.v. cyclophosphamide, methotrexate, 5-fluorouracil regimen. Patients with estrogen receptor (ER)-positive primary tumors received 5 years of adjuvant tamoxifen. Pretreatment, p53 (P=0.007), c-erbB2 (P<0.01), and Ki67 (P=0.02) were directly associated with CAIX expression, while bcl2 (P<0.000) and ER (P=0.000) and progesterone receptor (PgR; P<0.01) were inversely correlated. In multivariate analysis, only high p53 and low bcl2 were independently associated with CAIX positivity. CAIX immunostaining was significantly associated with poor outcome for DFS (P<0.002) and overall survival (P=0.001). In multivariate analysis, a significant interaction was found between CAIX and markers of hormone sensitivity, bcl2 (P=0.01), ER (P=0.02), PgR (P=0.02), and lymph node involvement (P=0.04), in predicting DFS. Presently, there are few clinical markers of resistance to tamoxifen treatment in ER-positive tumors. CAIX expression in breast cancer patients shows a negative predictive role of treatment efficacy in ER-positive patients on the adjuvant tamoxifen after primary chemo-endocrine therapy. Studies investigating the effects of pH on tamoxifen uptake and the effects of therapy with CA inhibitors are planned.     

Estradiol and progesterone receptors in human cutaneous melanoma

The presence of estradiol and progesterone receptors (ER and PR, respectively) was assessed in 24 removed cutaneous melanomas, adapting the routine procedure used for the detection of the presence of these steroid hormone receptors in breast cancers. The study included only those cases which were not subjected to any anticancer therapy before surgery. The ER and PR values were comparable to those found in breast cancer and the tumors thus investigated could be classified in the same four distinct groups, namely ER+PR+, ER+PR-, ER-PR+, and ER-PR-. Each group is expected to exhibit a specific rate of response to endocrine therapy. No relation was found between the presence of steroid receptors and the type of tumor tissues (benign and primary tumors, recurrences or metastases), or the sex of the patients. Because of the small number of cases in each age group we could not correlate the levels of ER+ and PR+ with the age of the patients. Saturation analysis, competition studies and Scatchard analysis were performed in order to determine the characteristics of ER. Our data suggest that cutaneous melanoma cytosols contain a saturable, high affinity and low capacity, specific binding component for estradiol. Further investigations are required to show that estrogen responsive tissues are functional in either melanocytes or melanomas from any species.     

Immunohistochemical analysis of human uterine estrogen and progesterone receptors throughout the menstrual cycle

Estrogen receptors (ER) and progesterone receptors (PgR) were studied immunohistochemically using specific antireceptor monoclonal antibodies in uterine tissue samples from 33 women in various stages of the menstrual cycle. Immunohistochemical localization was quantified as to intensity of staining and tissue distribution in glandular epithelium, stroma, and myometrium, and the results were compared with those of standard ligand binding assays. In all samples ER and PgR localized within the nuclei of target cells. The maximal concentrations of ER and PgR occurred in the mid- to late proliferative phase of the menstrual cycle. ER content declined throughout the secretory phase. In contrast, PgR content underwent unexpectedly complex and dyssynchronous fluctuations during the secretory phase of the menstrual cycle. Specifically, the glandular epithelium had diminished PgR content, while the stroma and myometrium maintained a significant PgR content. PgR and perhaps ER are not concordant in different cell types within the uterus. Segregation of function through alteration of receptor content may be an important mechanism in steroid-dependent growth and differentiation of target tissues.     

Factors associated with prognosis in human breast cancer. V. The simultaneous use of estrogen and progesterone receptor measurements for prediction of short-term relapse

Prediction of individual fate of breast cancer patients is one of the most important subjects studied because of the heterogeneity of the disease and the possibility of establishment of new therapeutic strategies. Hormone receptors have been recognized to be a valuable tool in prognosis at least in regard to short-term relapse. We have analyzed 400 patients in which hormone receptors has been determined, through stratification techniques, in 18-month and 3-year periods of disease-free interval. Clinical stage was chosen at the most important predictor in the total number of patients, lymph node status was the first predictor, estradiol receptor (ER) automatically was the second one, and the amount of receptor content had an important role in prognosis also. Inside Stage III patients ER should be the first predictor. Remarkable and independent association of progesterone receptor (PgR) content with relapse could be established. Predictive ability of ER and PgR inside lymph node status groups of patients was clearly shown. There was a remarkable difference between polar groups (lymph node-negative, ER+PgR+6% of relapse, and lymph node-positive, ER-PgR-30% of relapse) estrogen receptor status retains its predictive value, at the third year.     

The nontransformed progesterone and estrogen receptors in gastric cancer.

Contents of the progesterone receptors (PgR) and estrogen receptors (ER) in 18 gastric adenocarcinoma tissues were determined using both the dextran-coated charcoal (DCC) assay and enzyme immunoassay (EIA). PgR were found in 15 cancer tissues (range, 1.0-58.8 fmol/mg protein) and 12 normal mucosal tissues (range, 1.4-26.8 fmol/mg protein) by DCC assay, whereas only 6 cancer tissues (ranged, 0.2-3.3 fmol/mg protein) and 7 normal mucosal tissues (range, 0.1-0.8 fmol/mg protein) had measurable PgR by EIA analysis. Similar results were observed for ER. DCC assay found ER in 12 cancer tissues (range, 2.9-112.6 fmol/mg protein) and 12 normal mucosal tissues (range, 1.2-36.6 fmol/mg protein), whereas EIA measured ER in 16 cancer tissues (range, 0.1-3.5 fmol/mg protein) and 15 normal mucosal tissues (range, 0.1-4.8 fmol/mg protein). No significant correlation between DCC and EIA was observed for either PgR or ER. DCC assay and its modified procedures including 5% DCC stripping of cytosol and/or the addition of sodium molybdate in buffer were simultaneously measured in 5 gastric adenocarcinoma tissues and 1 gastritis cystica polyposa tissue (a precancerous lesion). Higher receptor levels were found by the modified procedures than by conventional method. Using the DCC procedure with addition of sodium molybdate in buffer for receptor analysis, PgR and ER were found in gastric tissues in six patients, with significantly increased levels of measurable PgR. The results suggest that PgR and ER may be involved in the physiology of normal and gastric cancer tissues; their clinical implications are worthy of further study.     

Selective estrogen receptor modulator effects in the rat brain.

The effects in the brain of selective estrogen receptor modulators (SERMs) such as tamoxifen and raloxifene have not yet been fully elucidated. Based upon the hypothesis that serotonin (5-HT)-steroid hormone interactions are important in mood regulation, we have compared six SERMs (tamoxifen, raloxifene, levormeloxifene, NNC 45-0781, NNC 45-0320, NNC 45-1506) with 17beta-estradiol (E(2)) in terms of their ability to regulate mRNA levels of estrogen receptor (ER)alpha, ER beta, 5-HT(1A) receptor, and 5-HT reuptake transporter (SERT) in the midbrain, amygdala, and hypothalamus of ovariectomized (OVX) rats. Female rats (n = 6/group, 8 groups total) were OVX and allowed to recover for 2 weeks. During the third post-OVX week, rats were injected subcutaneously with E(2) (0.1 mg/kg) or one of the SERMs (5 mg/kg) once per day for 7 days. Twenty-four hours after the last injection, tissue was collected for the determination of mRNA levels by ribonuclease protection assay (RPA). E(2) treatment significantly decreased mRNA levels for ER alpha, ER beta, and SERT in midbrain and ER alpha in hypothalamus. Tamoxifen increased ER beta mRNA levels in hypothalamus, while raloxifene increased ER beta mRNA levels in amygdala. NNC 45-0320 decreased ER alpha mRNA in hypothalamus and decreased ER beta mRNA in amygdala. These results suggest that while SERMs are not full estrogen receptor agonists in the brain, the agonist/antagonist profiles for individual SERMs may differ among brain areas. This raises the possibility of developing new SERMs for selective functions in specific brain areas.     

Estrogen receptor agonists alleviate cardiac and renal oxidative injury in rats with renovascular hypertension

Although endogenous estrogen is known to offer cardiac and vascular protection, the involvement of estrogen receptors in mediating the protective effect of estrogen on hypertension-induced cardiovascular and renal injury is not fully explained. We aimed to investigate the effects of estrogen receptor (ER) agonists on oxidative injury, cardiovascular and renal functions of rats with renovascular hypertension (RVH). Female Sprague-Dawley rats were randomly divided as control and RVH groups, and RVH groups had either ovariectomy (OVX) or sham-OVX. Sham-OVX-RVH and OVX-RVH groups received either ERβ agonist diarylpropiolnitrile (1 mg/kg/day) or ERα agonist propyl pyrazole triol (1 mg/kg/day) for 6 weeks starting at the third week following the surgery. At the end of the 9^th week, systolic blood pressures were recorded, cardiac functions were determined, and the contraction/relaxation responses of aortic rings were obtained. Serum creatinine levels, tissue malondialdehyde, glutathione, superoxide dismutase, catalase levels, and myeloperoxidase activity in heart and kidney samples were analyzed, and Na⁺, K⁺-ATPase activity was measured in kidney samples. In both sham-OVX and OVX rats, both agonists reduced blood pressure and reversed the impaired contractile performance of the heart, while ERβ agonist improved renal functions in both the OVX and non-OVX rats. Both agonists reduced neutrophil infiltration, lipid peroxidation, and elevated antioxidant levels in the heart, but a more ERβ-mediated protective effect was observed in the kidney. Our data suggest that activation of ERβ might play a role in preserving the function of the stenotic kidney and delaying the progression of renal injury, while both receptors mediate similar cardioprotective effects.     

Relationships of steroid hormone receptors, age and histological characteristics in human breast cancer

A number of 178 human primary mammary carcinomas were evaluated for estradiol receptor (ER) content, patients' age, histologic type, tumor histological grade of differentiation and content of elastosis. For a subset of 78 cases progesterone receptor (PR) was also assayed. ER positivity was significantly elevated in patients over 50 years while PR positivity rate was increased in patients under 50; ER-positive-PR-positive (ER + PR +) cases were evenly distributed among age groups. Correlations of ER and PR with histological features revealed that: a) high levels of ER were found in lobular, cribriform and colloid carcinomas; b) ER+ cases but not PR+ tumors were more frequent in well differentiated tumors; c) ER+, PR+ and ER+ +PR+ tumors were strongly related to the presence of elastosis; d) contrasting with ER-PR+ tumors, ER+ PR+ cases were associated with features indicative of a favorable prognosis. It is concluded that the determination of ER and PR in mammary malignant tumors brings information regarding the evolution of breast cancer in human patients and the biology of malignant mammary cells.     

Cytosolic and nuclear androgen receptor activity in the cancer of the larynx

It is well known that the larynx is a target organ for androgens and the cancer of larynx is more frequent in male subjects. We have evaluated the androgen receptors (AR) in the cytosol (ACR) and in salt extractable (ANR) and salt resistant nuclear fraction (AMR) in a group of 24 male patients with cancer of the larynx surgically removed. In addition specimens obtained from the normal mucosa of the same subjects were analyzed. In 5 patients estrogen (ER) and progesterone (PgR) receptors were also assayed. In all subjects blood samples were taken before surgery for the assay of the following hormones: LH, FSH, estradiol, testosterone, dihydrotestosterone, delta 4-androstenedione, dehydroepiandrosterone sulfate, cortisol. The results observed showed that 18 out of 24 normal larynx mucosa specimens and 17 out of 24 larynx cancer specimens were positive for ACR or ANR or AMR. The 5 samples of normal and cancer tissues analyzed for ER and PgR were negative. In conclusion there is no significant correlation between AR positivity from one size, histology, degree of differentiation and invasivity of the cancer, age of patients and hormonal blood levels from the other. The high ANR and AMR positivity (normal hormonal translocation and binding on DNA acceptors) confirm that the normal and cancer larynx are target tissue for androgens and establish the hormone dependence of this cancer. Hormonal therapy could be envisaged as an alternative or a complementary therapy for this type of cancer at least in the cases in which the analysis of hormone receptors will prove to be positive.     

Effects of estrogen and endocrine therapeutic agents on the estrogen receptor, progesterone receptor and DNA synthesis in MCF-7 human breast cancer cells using the whole cell uptake method

In order to investigate the mechanisms of the endocrine therapeutic agents and the applicability of combined endocrine therapies for breast cancers, we studied the effects of estrogen and the endocrine therapeutic agents on estrogen receptor (ER), progesterone receptor (PgR), and DNA synthesis in MCF-7 human breast cancer cells, which is known to be sensitive to estrogen. ER and PgR of MCF-7 cells were determined by whole cell uptake method. In brief, intact MCF-7 cells cultured in the multi-well plates were incubated with various concentrations of tritiated estradiol (E2) or promegestone (R5020) at 37 degrees C for 1 hour. The characteristics of the hormone binding were analyzed by Scatchard plots. MCF-7 cells had single class of ER (Kd: 2.1 +/- 0.2 X 10(-10) M, MBC: 9.0 +/- 1.5 X 10(3) sites/cell) and PgR (Kd: 7.2 +/- 1.1 X 10(-10) M, MBC: 3.1 +/- 0.5 X 10(4) sites/cell). When cultured in the presence of 10(-8) M or 10(-6) M of E2, tamoxifen (TAM), R5020 or medroxyprogesterone acetate (MPA) for 48 hrs, the numbers of binding sites of ER and PgR altered, but the affinities of either of them did not change. E2(10(-8) or 10(-6) M) increased about twice the number of PgR. Although treatment of 10(-8) M TAM, a non-steroidal antiestrogen, slightly increased the number of PgR, 10(-6) M TAM significantly decreased the number of PgR. Both of R5020 (10(-8) or 10(-6) M) and MPA (10(-8) or 10(-6) M), synthetic progestins, decreased the number of ER dose-dependently. On the other hand, E2 (10(-8) and 10(-6) M) and R5020 (10(-8) M) enhanced DNA synthesis, but 10(-6) M TAM or MPA inhibited DNA synthesis. The effects of single, sequential and coincidental treatment of these agents were compared. The sequential treatment of 10(-8) M E2 for 36 hrs and followed 10(-6) M MPA for 36 hrs ("10(-8) M E2----10(-6) M MPA") and "10(-6) M TAM----10(-6) M MPA" inhibited DNA synthesis of MCF-7 cells more efficiently than 10(-6) M TAM alone or 10(-6) M MPA alone for 72 hrs. However, "10(-6) M MPA----10(-6) M TAM" inhibited DNA synthesis less than "10(-6) M TAM----10(-6) M MPA".(ABSTRACT TRUNCATED AT 400 WORDS)     

Estrogen receptor messenger RNA expression in rat hypothalamus as a function of genetic sex and estrogen dose

Previously, we showed that estrogen receptor (ER) messenger RNA (mRNA) levels are decreased in cells of the mediobasal hypothalamus of ovariectomized (OVX) female rats following an acute estradiol treatment. Here, we examined whether the level of ER mRNA remains depressed in the continued long-term presence of estradiol, and questioned if there is a systematic relationship between the concentration of estradiol and the decrease in ER mRNA level. OVX female rats were implanted for 2 weeks with silastic capsules containing various concentrations of estradiol. Tissue sections were hybridized with a [3H] single-stranded DNA probe prepared from the region of the rat ER complementary DNA corresponding to the steroid binding domain, and relative mRNA level was assessed by counting grains over cells in specific hypothalamic nuclei. Estradiol induced a dose-dependent decrease in ER mRNA levels. Message levels declined in the ventrolateral aspect of the ventromedial nucleus (VLVM) by 57% and in the arcuate nucleus by 62% at the highest hormone concentrations used. Thus, ER mRNA down-regulation in female rat hypothalamus exhibits orderly dose dependence at a time following hormone treatment which ensures the system is at steady state. A second study determined if there exist differences in basal levels of ER mRNA expression between castrated (CAS) females and males, and if estradiol can down-regulate ER mRNA levels in male hypothalamus. CAS rats of both sexes were exposed acutely to estradiol benzoate (EB) for different periods of time. Again, in females, EB significantly decreased ER mRNA levels in VLVM by 55% (18 h) and in the arcuate nucleus by 74% (18 h). Interestingly, control CAS males had significantly lower basal ER mRNA levels than OVX females (52% lower than female levels in VLVM; 56% in arcuate), suggesting a sex difference in constitutive expression levels. Moreover, EB failed to down-regulate significantly ER message levels in males. There was no significant effect of sex or EB treatment on ER mRNA levels in medial amygdala. Thus, the second study shows sex differences and brain-region specificity in hormonal regulation of ER mRNA. These findings show that differences in basal levels and regulation of ER mRNA could be a substrate for sex differences in ER concentrations in the hypothalamus of the rat, and further raise the possibility of sex differences in concentrations of nuclear proteins related to the control of ER gene expression.