Progesterone Receptor Content Research Articles

Uterine estradiol and progesterone receptor concentration, activities of certain antioxidant enzymes and dehydrogenases and histoarchitecture in relation to time of secretion of nidatory estrogen and high endometrial sensitivity in rat.

Alterations in uterine nuclear and cytosolic estradiol (ER) and progesterone (PR) receptor concentration, activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), glucose-6-phosphate dehydrogenase (G-6-PDH) and lactate dehydrogenase (LDH), surface and transmission electron microscopy and histology in relation to the time of secretion of nidatory estrogen and the onset of endometrial sensitivity in the rat were investigated. A significant increase in plasma estradiol (E2) concentration in control rats was observed at 22.00 h on day 4 post-coitum, whereas progesterone (P) concentration increased at 17.00 h on day 4 and was maintained until 17.00 h on day 5. The period of high endometrial sensitivity (10.00 h on day 5) was characterized by elevated uterine cytosolic ER and nuclear and cytosolic PR concentration and POD activity, low columnar luminal epithelium with undulating surface and intercellular membranes, covered with short microvilli and pinopods, and containing numerous electron-transparent apical vesicles, mitochondria, polyribosomes, rough (RER) and smooth (SER) endoplasmic reticulum, well developed Golgi, few lysosomes and lipid droplets and loose edematous antimesometrial stroma. Inhibition in endometrial sensitivity by post-coital centchroman was associated with a marked depletion in uterine cytosolic ER and an increase in nuclear ER concentration, a decrease in POD and G-6-PDH activities, compact fibroblastic stroma, an increase in luminal epithelial cell height with decreased RER, SER, polyribosomes, Golgi, straightening of intercellular membranes, reduced surface undulations and absence of pinopods. Electron-transparent vesicles appeared flattened and clumped in the apical portion of cells, tight junctions were more prominent and lipid droplets were translucent. Nuclear and cytosolic PR and the pattern of secretion or plasma E2 and P remained unaffected. CAT, SOD and LDH activities, although high throughout pre-implantation, did not vary in relation to the secretion of nidatory estrogen, endometrial sensitivity or centchroman treatment.

Response-specific antiestrogen resistance in a newly characterized MCF-7 human breast cancer cell line resulting from long-term exposure to trans-hydroxytamoxifen.

To understand better the antiestrogen-resistant phenotype that frequently develops in breast cancer patients receiving tamoxifen, we cultured MCF-7 breast cancer cells long-term (>1 yr) in the presence of the antiestrogen trans-hydroxytamoxifen (TOT) to generate a subline refractory to the growth-suppressive effects of TOT. This subline (designated MCF/TOT) showed growth stimulation, rather than inhibition, with TOT and diminished growth stimulation with estradiol (E2), yet remained as sensitive as the parental cells to growth suppression by another antiestrogen, ICI 164,384. Estrogen receptor (ER) levels were maintained at 40% of that in parent MCF-7 cells, but MCF/TOT cells failed to show an increase in progesterone receptor content in response to E2 or TOT treatment. In contrast, the MCF/TOT subline behaved like parental cells in terms of E2 and TOT regulation of ER and pS2 expression and transactivation of a transiently transfected estrogen-responsive gene construct. DNA sequencing of the hormone binding domain of the ER from both MCF-7 and MCF/TOT cells confirmed the presence of wild-type ER and exon 5 and exon 7 deletion splice variants, but showed no point mutations. Compared to the parental cells, the MCF/TOT subline showed reduced sensitivity to the growth-suppressive effects of retinoic acid and complete resistance to exogenous TGF-beta1. The altered growth responsiveness of MCF/TOT cells to TOT and TGF-beta1 was partly to fully reversible following TOT withdrawal for 16 weeks. Our findings underscore the fact that antiestrogen resistance is response-specific; that loss of growth suppression by TOT appears to be due to the acquisition of weak growth stimulation; and that resistance to TOT does not mean global resistance to other more pure antiestrogens such as ICI 164,384, implying that these antiestrogens must act by somewhat different mechanisms. The association of reduced retinoic acid responsiveness and insensitivity to exogenous TGF-beta with antiestrogen growth resistance in these cells supports the increasing evidence for interrelationships among cell regulatory pathways utilized by these three growth-suppressive agents in breast cancer cells. In addition, our findings indicate that one mechanism of antiestrogen resistance, as seen in MCF/TOT cells, may involve alterations in growth factor and other hormonal pathways that affect the ER response pathway.

Loss of heterozygosity at chromosome 1p in human breast cancer

232 human primary invasive breast tumors were analyzed with 13 polymorphic microsatellite markers specific to chromosome 1p. Loss of heterozygosity (LOH) was observed in 126 cases or 54% of the tumors. One marker, D1S496, at the 1p35 region showed the highest LOH, 28%. High frequencies of LOH were also detected by the markers, D1S488, D1S167 and D1S435, at the 1p31 region, 25%, 24% and 26% LOH, respectively. This suggests the presence of tumor suppressor genes at these two regions. Tumors with and without LOH at 1p were tested for association with clinico-pathological features of the tumors such as estrogen- and progesterone-receptor content (ER and PgR), age at diagnosis, tumor size, node status, histological type, S-phase fraction, ploidy, survival and LOH at chromosomes 3p, 6q, 9p, 11p, 11q, 13q, 16q, 17p and 17q. A significant association was found between LOH at chromosome 1p and high S-phase fraction and lower survival rate. Association was also found between LOH at 1p and chromosome regions 3p, 6q, 9p and 17q. A multivariate model including prognostic variables, showed that LOH at 1p is an independent prognostic variable and patients who have breast tumors with LOH at 1p have approximately a two-fold increase in relative risk of death. We conclude that screening for 1p deletions gives additional prognostic information that might be useful in breast cancer treatment.

Characterization of the functional progesterone receptor in an endometrial adenocarcinoma cell line (Ishikawa): progesterone-induced expression of the alpha1 integrin.

Endometrial progesterone receptors (PR) are regulated by both estrogen (E2) and progesterone (P) and mediate the expression of specific endometrial proteins. Ishikawa cells are a well-differentiated human endometrial adenocarcinoma cell line, with both estrogen receptors (ER) and PR, regulated in a manner similar to that of normal endometrium. Immunohistochemical and biochemical analyses demonstrate that the concentration of PR is increased by E2 priming and decreased by subsequent treatment with P. Scatchard plot analysis showed a K(d) of 1 nM. On the basis of biochemical analysis, PR concentrations reached approximately 1400 fmol/mg cytosol protein in cells after treatment with E2 (10(-8) M) for 4 days. Immunoprecipitation and Western blot studies revealed the presence of both the 116 kDa and 81 kDa proteins with multiple isoforms of the high molecular weight (MW) protein. Northern blot analysis demonstrated transcriptional control of PR by steroid treatment. These studies demonstrate the coordinate regulation of all PR mRNA species. The functionality of Ishikawa PR was demonstrated by the expression of alpha1beta1 integrin in response to E2 plus P, at the level of transcription and translation. This effect was blocked by the addition of the anti-progestin, RU-486. These studies reconfirm that the Ishikawa cell line is an excellent model for the study of hormonally regulated events in the human endometrial epithelium.

Synthesis, structure and biological properties of Z-17alpha-(2-iodovinyl)-11beta-chloromethyl estradiol-17beta (Z-CMIV), a high affinity ligand for the characterization of estrogen receptor-positive tumors.

Linkage of a 11beta-chloromethyl group to estradiol-17beta (E2) dramatically increases the binding affinity of the steroid for the estrogen receptor (ER) with the formation of a quasi-irreversible steroid-receptor complex. We have synthesized the two isomers of 11beta-chloromethyl-17alpha-iodovinyl-estradiol (E-CMIV and Z-CMIV) by a novel route. Both derivatives demonstrated high binding affinity and selectivity for ER (RBAs: ER = 820 and 1008; SHBG = 1.2 and 0.25, respectively; E2 = 100). On the basis of X-ray crystallographic data for Z-CMIV and its precursor, we have postulated that Z-CMIV might interact strongly with aromatic amino-acids within a hydrophobic groove of the ER hormone binding domain (HBD) that incorporates pockets corresponding to the 11beta and 17alpha steroid substituents. The binding properties of Z-CMIV labeled with 125I were investigated, especially its ability to detect and quantify altered ER forms with low binding affinity for E2. Sucrose density gradient analysis revealed that Z-CMIV has a higher activation potency than E2 as it converts a higher proportion of non-activated monomers in the cytosol into activated monomers with the potential to dimerize. In in vitro (MCF-7 cells) and in vivo (rat uterus) determinations of estrogenic activity, Z-CMIV was as potent as E2 in increasing progesterone receptor (PgR) concentrations and decreasing ER levels and in stimulating uterine growth. [125I]-Z-CMIV could open the way to new applications in the diagnosis and therapy of ER-positive breast cancers, especially those containing altered (variant) ERs.

Immunohistochemical assessment of oestrogen receptor and progesterone receptor distribution in biopsy samples of the bovine endometrium collected throughout the oestrous cycle

Abstract The study was designed to determine the distribution of oestrogen receptors (OR) and progesterone receptors (PR) in specific endometrial cell population during the oestrous cycle. Uterine biopsy samples and blood were obtained from five clinically healthy cows at Days 1 (initiation of behavioural oestrus), 8, 15 and 19 of the oestrous cycle. All animals conceived after biopsy regimen. Immunoperoxidase staining techniques at light microscopic level were used to localise OR and PR. Specific positive staining reactions for both receptors were always limited to cell nuclei. Immunoreactivity was scored semiquantitatively. In the surface epithelium, OR were detectable throughout the oestrous cycle and exhibited a significant increase from Days 8 to 15. In stromal cells and glandular epithelial cells, however, staining intensities for OR were strong at behavioural oestrus (Day 1). Significantly lower immunoreactivities were recorded at cycle Day 15. At oestrus, and to a lesser extent at Day 8, a significant gradient in oestrogen receptor content was evident, showing increasing immunoreactivity with the depth of the endometrial tissue. In surface epithelial cells, significantly more progesterone receptor immunoreactivity was evident at Day 8 as compared with Days 1, 15 and 19. In glandular epithelia, only some PR stained at oestrus, many of them occurred at Day 8 and very few could occasionally be seen at Days 15 and 19. In stromal cells, PR exhibited a somewhat different quantitative staining pattern, i.e. many occurred at Days 1, 8 and 19. A significant decrease in immunoreactivity was observed between Days 8 and 15. While occasionally recorded smooth muscle cells of the myometrium could exhibit even strong immunoreactivities for both receptors, such cells of the tunica media of blood vessels were almost devoid of OR and PR. Caruncular tissue districts, in a few cases included in biopsy specimens, did not differ substantially from intercaruncular endometrium in OR and PR contents. Endothelial cells, granulocytes and lymphocytes always were devoid of specific nuclear staining. In the present study, OR and PR contents of the bovine endometrium exhibit cell type and location specific reaction patterns during the oestrous cycle. This suggests that different cell types within this target organ can respond in a different manner to identical hormonal stimuli.

Non-competitive anti-oestrogenic actions of progesterone antagonists in primate endometrium: enhancement of oestrogen and progesterone receptors with blockade of post-receptor proliferative mechanisms.

Previous studies have shown that the progesterone antagonists (antiprogestins) inhibit oestrogen-dependent endometrial proliferation in ovariectomized monkeys, without having affinity to the oestrogen receptor (ER). This study was designed to investigate the effect of the antiprogestins mifepristone (RU 486) and onapristone (ZK 98,299), on the concentration of ER and progesterone receptor (PR) in the endometrium of long-term ovariectomized cynomolgus monkeys (Macaca fascicularis). In untreated monkeys, tissue preparations bound in total 228 +/- 68 pmol [3H]-oestradiol/g protein (ER), and 119 +/- 42 pmol [3H]-R5020/g protein (PR). These values were not significantly different from the total binding capacities of tissues from monkeys treated with RU 486 alone or primates treated with oestradiol plus progesterone. Treatment with oestradiol alone almost doubled the ER and PR concentrations. Combined treatment with oestradiol and RU 486 enhanced the ER and PR concentrations in a dose-dependent manner: 1 mg/kg body weight (bw) RU 486/kg increased both ER and PR contents about 3-fold. The dose of 5mg/kg bw RU 486 or onapristone increased the ER and PR concentrations almost 6- and 5-fold respectively, compared with the oestradiol-treated controls. Our results demonstrate that RU 486 and onapristone increased the endometrial ER and PR concentrations far beyond the physiological level in ovariectomized, oestradiol-treated monkeys. Whether the over-expression of ER and PR in the presence of antiprogestins is causally related to the antiproliferative impact of antiprogestins in the endometrium (non-competitive anti-oestrogenic effects) or is an independent action in unknown.

The role of estradiol, progesterone, and transforming growth factor on human endometrioma cell culture.

The present study demonstrates several aspects of endometrioma cells in culture, namely, 1) cell growth, proliferation, and morphology, 2) effect of cell culture on estrogen and progesterone receptor concentration, 3) effect of estradiol, progesterone, and transforming growth factor. The tissue sample was obtained from ovarian endometriomas that were removed via laparotomy or laparoscopy. The tissue sample was digested with collagenase. After washing, the tissue was cultured in endothelial cell culture medium. Cell count was done by flow cytometry. Receptor study was done by immunohistochemistry. The results demonstrated the growth and proliferation of endometrioma cell in culture medium. Electron microscopy showed stroma-like cells. The cells lost their estrogen and progesterone receptors. Estradiol and progesterone added to these cultures did not affect the rate of growth and proliferation of the cells. Transforming growth factor significantly increased the rate of growth and proliferation of these cells.

Why are there two progesterone receptors?

<h2>Abstract</h2> This year represents the 20th anniversary of our first demonstration that human breast cancers contain progesterone receptors (PR), and are markers of hormone dependence. These receptors are now routinely measured in tumours not only as markers of hormone dependence, but of disease prognosis. Theoretically, their central function in breast cancers is not as markers, but as effectors of the proliferative signals of endogenous progesterone in premenopausal women, and as targets for progestins and antiprogestins. At present, PR are rarely measured for these functional purposes. The actions of PR are complex, and responsiveness to progestin agonists or antagonists will depend on the gene whose activity is being measured, the peculiarities of the cell and tissue under study, and most importantly, the PR isoform that predominates in a tissue or tumour. The differential expression of PR isoforms, serves, we believe, to fine-tune responsiveness to this important reproductive hormone. Knowledge, not just of the PR content of a tissue, but of the expression of B- vs Areceptors in that tissue, will be vital to understanding the effects of progestins therein. Recent studies with PR have forced us to revise the standard model of steroid receptor action. The conventional model, which depicts receptors as ligand-activated proteins that bind to specific DNA sequences at ‘consensus' hormone response elements and activate transcription, is not incorrect. It is, however, oversimplified, as studies with PR demonstrate. These demands include requirements for both positive and negative transcriptional regulation; for tissue specificity of action; and for regulation of composite and simple gene promoters. Multiple functional domains control intramolecular contacts, intermolecular protein-protein interactions, and DNA binding. As steroid antagonists are synthetic rather than natural hormones, their binding produces structural alterations in the receptors that unveil additional novel interactive capabilities. While antiprogestins competitively inhibit agonists by forming non-productive receptor-DNA complexes, this is not their sole mechanism of action. Antiprogestin effects may also be mediated by receptor interactions with coactivators whose function is in turn controlled by non-steroidal signals. When two different signalling pathways are activated simultaneously they can cooperate to produce unintended effects. Additionally, it seems clear that antagonist-occupied receptors can act without binding to canonical PREs, or without binding to DNA at all, relying perhaps on tethering proteins. This may be a consequence of the unusual allosteric structure imparted on the receptors by synthetic ligands. For some of these unusual actions, the receptors may even be monomeric rather than dimeric. Investigators should not assume when studying antiprogestins that a specific mechanism is operating. These novel actions begin to explain two properties of steroid antagonists that have puzzled investigators. One is the common observation that antagonists are agonists in some normal tissues. The other, an extension of the first, is that in malignant cells, antagonists can acquire agonist-like properties as tumours progress, leading to treatment failure. Although such tumours are called ‘resistant', they may in fact be responding quite well to the antagonist! With respect to receptor protein structure, we are only beginning to appreciate its complexity. For example, it appeared initially that the structural independence of functional domains permitted analysis of receptor fragments by fusing them to heterologous proteins. However, we now know that important functional domains can overlap; that other functional domains may be discontinuous; and that one domain can modulate the activity of another. This means that analysis of receptor fragments in chimeras is an incomplete test of domain function, and that we need innovative experimental strategies to understand this intramolecular cross-talk.

Immunohistochemical detection of cathepsin D in endometrium from long-term subdermal levonorgestrel users and during the normal menstrual cycle.

A previous report has shown that progesterone up-regulates cathepsin D expression in human endometrial cell culture. In women using the levonorgestrel-releasing Implant Norplant, the plasma levonorgestrel and immunoreactive endometrial progesterone receptor concentrations are elevated. However, the functional status of these receptors is not known. This study used endometrial cathepsin D expression both as an indirect marker for the functional status of endometrial progesterone receptors, and to identify the cell types that express cathepsin D. The results show that cathepsin D is primarily found in glandular epithelia and luminal epithelia in control and Norplant endometria. There is no significant difference in cathepsin D expression between the control and Norplant endometria, between the various stages of the menstrual cycle, or between Norplant users with varying degrees of breakthrough bleeding. Cathepsin D is also detected in cells scattered in the stroma in both control and Norplant endometria. The majority of these cells are macrophages. These data indicate that there is no evidence for progesterone regulation of cathepsin D in the human endometrium. Cathepsin D thus cannot be used as a marker for the functional status of progesterone receptors found in the Norplant-exposed endometrium.

The effects of high dietary fat and indomethacin on 7,12-dimethylbenz(a)anthracene-induced mammary carcinomas in rats

The effects of high dietary fat and indomethacin (IND) on tumorigenesis, tumor growth, tumor histology, cell kinetics and receptor contents of 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary carcinomas were investigated in Sprague-Dawley (S-D) rats. Tumorigenesis was stimulated by high dietary fat and inhibited by IND. However, both high dietary fat and IND stimulated tumor growth. Switching the animals from the high-fat diet with or without IND to the low-fat diet suppressed tumor growth and affected the cell kinetics. Histologically, the tumors showed a dense proliferation of ductal cells in the high-fat alone or IND-treated high-fat diet group. Tumors in the low-fat or IND-treated low-fat group, as well as the group switched from a high-fat or IND-treated high-fat diet to a low-fat diet, demonstrated well-developed glandular structures. The estrogen receptor and progesterone receptor contents were not different between the groups either prior to or following switching diets. Therefore, high dietary fat stimulates tumorigenesis and tumor proliferation, while IND has dual effects: a stimulating effect on tumor proliferation, but an inhibiting effect on tumorigenesis. It also appears that hormone-receptor status does not play an important role in the stimulatory effects of high-fat diet or IND on tumor proliferation.

Relevance of estrogen and progesterone receptors enzyme immunoassay in malignant, benign and surrounding normal thyroid tissue

Several authors have demonstrated the presence of estrogen receptors (ER) and progesterone receptors (PR) in thyroid tissue, generally using dextran coated charcoal method (DCCA). The aim of the study was to measure ER and PR in thyroid specimens using an immunoenzymatic method, and to evaluate the meaning of different prevalence of ER and PR in malignant and benign thyroid disease, as compared with normal thyroid tissue. We have measured ER and PR in thyroid tissue from 28 benign and 20 malignant thyroid lesions, and in 38 samples of surrounding normal thyroid tissues. The sensitivity of ER-EIA and PR-EIA was 1.0 and 1.5 fmol/mg protein, respectively. In thyroid carcinoma the frequency of ER positivity (ER+) was 7/20 (35%); it was significantly higher in the surrounding normal tissue (15/20; 71%) (p = 0.03). In benign thyroid disease, the prevalence of ER+ was 11/28 (39%) and in the surrounding normal tissue it was 11/18 (61%) (p = not significant). PR+ was detected in 7/20 (35%) thyroid cancers and in 15/28 (53%) benign lesions without significant difference with the frequency detected in the surrounding normal tissues. ER and PR concentrations (mean +/- SD) in thyroid cancer was 2.2 +/- 2.2 and 2.2 +/- 2.9 respectively, similarly to that detected in benign thyroid disease and in normal tissue. The simultaneous presence of ER and PR (ER+PR+) was also evaluated. We have found that the frequency of ER+ PR+ was significantly higher in benign lesions (8/28; 28.6%) as compared with malignant samples (1/20; 5%) (p < 0.05); the frequency of ER+PR+ was significantly higher in normal tissue surrounding the malignant lesions (9/20; 45) (p = 0.003). Our data indicate i) EIA method is appropriate to detect ER and PR in thyroid tissue. ii) The frequency of ER+ and ER+PR+ specimens is significantly higher in normal thyroid tissue than in pathologic tissues. This indicates that ER and PR immunoassays may be useful tools to evaluate the normal biological activity of thyroid cells.

Morphometric, immunohistological and threedimensional evaluation of the endometrium of menopausal women treated by oestrogen and Crinone, a new slow-release vaginal progesterone

Recently advanced computerized technology was applied to the investigation of morphometric, immunohistological and three-dimensional changes of the endometrial mucosa in order to evaluate quantitatively the effects of three doses of a new slow-release vaginal progesterone on the endometrium in post-menopausal women. A total of 20 menopausal women, deprived of ovarian function, were given oestrogen for 12 days and a combined therapy of oestrogen (administered orally) and progesterone for another 12 day period. Progesterone was administered vaginally through a new gel (Crinone) utilizing a bioadhesive, biocompatible polymer as a base to achieve a sustained release effect. An endometrial biopsy was taken before treatment, after oestrogen-only treatment and after the oestro-progestogen therapy. Before treatment, all the patients exhibited an atrophic endometrium. After oestrogen-only treatment, typical proliferative changes occurred: an increase in the endometrium thickness, an increase in the mitotic index, numerous cylinder-like glands and no coiled glands, and high concentrations of oestrogen receptors (ER) and progesterone receptors (PR). After the oestro-progestogen therapy, whatever the dose of progesterone given, a secretory transformation of the endometrial mucosa occurred, mitotic activity decreased significantly, more ramified and coiled glands were observed, and a decrease in PR content was noted in epithelial and stromal nuclei, and a decrease in PR content was also observed in epithelial nuclei but not in stromal nuclei. Accurate new techniques of image analysis have shown that crinone therapy could eliminate the proliferative effects of oestrogen treatment in post-menopausal women, despite doses as low as 45 mg of progesterone administered vaginally every other day. The results suggest that the sustained release effects of Crinone are clinically relevant.

Methods for simultaneous interphase in situ hybridization and nuclear antigen immunocytochemistry in T47-D cells.

Procedures that combine immunocytochemistry (ICC) and in situ hybridization (ISH) techniques are now used to investigate phenotype/genotype relationships in the same cells. In this report we describe three rapid procedures for simultaneous detection of a nuclear antigen, progesterone receptors (PR), and the centromeric region of chromosome 11 (to which the human PR gene has been assigned) in T47-D cells. Proteins were stained by precipitates of horseradish peroxidase-diaminobenzidine (PO-DAB, brown color), alkaline phosphatase-Fast Red (APase-Fast Red, red color) or alkaline phosphatase-nitroblue tetrazolium-X-phosphate (APase-NBT-X-Phosphate, blue color) respectively. To obtain a suitable contrast for the two labels, we detected DNA on PO-DAB and APase-NBT-X-phosphate-immunostained cells with interphasic fluorescent in situ hybridization (FISH). By contrast, we combined the APase-Fast Red ICC with an immunocytochemical ISH using alkaline phosphatase-NBT-X-phosphate detection. Only the procedure combining APase-NBT-X-phosphate ICC and FISH ensures optimal visualization of both the PR content and the number of chromosome 11. This method easily provides simultaneous localization of DNA and protein targets in the same cells and should be applicable to many other situations.

Changes in radiation sensitivity and steroid receptor content induced by hormonal agents and ionizing radiation in breast cancer cells in vitro.

Possible influences of tamoxifen and estradiol on in vitro radiation sensitivity and cellular receptor content after irradiation and/or tamoxifen treatment were studied in breast cancer cell lines; estrogen receptor (ER) and progesterone receptor (PgR) positive cell lines MCF-7 and MCF-7/TAM(R)-1 and the ER and PgR negative cell line MDA-MB-231. The tamoxifen resistant MCF-7/TAM(R)-1 cells were more resistant to ionizing radiation than the MCF-7 and MDA-MB-231 cells. Exposure to tamoxifen made the MCF-7 cells more radiation resistant, while estradiol made the MDA-MB-231 cells more radiation sensitive. A radiation dose of 6 Gy reduced the ER content in cytosol in both MCF-7 and MCF-7/TAM(R)-1 cells, but brought no alterations to the PgR content. In MCF-7/TAM(R)-1 cells tamoxifen exposure significantly increased the ER and reduced the PgR content, an effect not observed in the MCF-7 cells. To conclude, the present study indicates that irradiation and tamoxifen may modify the ER and PgR content in cytosol in breast cancer cells. Hormonal treatment may alter the radiation sensitivity, even in ER negative cells, suggesting that hormonal agents may act both via receptor and non-receptor binding mechanisms.

Effects of hormone replacement therapy on the mammary gland of surgically postmenopausal cynomolgus macaques

OBJECTIVE: Our purpose was to define the proliferative response and receptor status in the mammary glands of surgically postmenopausal macaques given hormone replacement therapy, equivalent for monkeys to that given women. STUDY DESIGN: Surgically postmenopausal adult female cynomolgus macaques (Macaca fascicularis) were given either no treatment ( n = 26), conjugated equine estrogens ( n = 22), or combined therapy with conjugated equine estrogens and medroxyprogesterone acetate ( n = 21). Drugs were administered in the diet, at doses equivalent on a caloric basis to 0.625 mg per woman per day for conjugated equine estrogens and 2.5 mg per woman per day for medroxyprogesterone acetate, for 30 months. Mammary gland proliferation was assessed subjectively and by morphometric and stereologic means. Estrogen receptor and progesterone receptor content and proliferation were studied by immunohistochemistry. RESULTS: In this model combined therapy with conjugated equine estrogens and medroxyprogesterone acetate induced greater proliferation than did conjugated equine estrogens alone. The percentage of estrogen receptor - positive cells was decreased in the conjugated equine estrogens plus medroxyprogesterone acetate group. The percentage of progesterone receptor - positive cells was increased by treatment with conjugated equine estrogens alone. CONCLUSION: These results indicate a proliferative response of mammary gland epithelium to therapy with conjugated equine estrogens plus medroxyprogesterone acetate in postmenopausal macaques. The clinical implication of this finding may be a greater risk for development of breast neoplasms in women receiving combined hormone replacement therapy. (A M J O BSTET G YNECOL 1996;174:93-100.)

Immunohistological Detection of Estrogen and Progesterone Receptors in Multiple and Well Differentiated Leiomyomatous Lung Tumors in Women with Uterine Leiomyomas (so-called Benign Metastasizing Leiomyomas): A Report on 5 Cases

Seventy-four cases of so-called "benign metastasizing uterine leiomyomata" are reported in the literature. In these cases, well differentiated, leiomyomatous lung tumors developed, usually after a period of several years. Histologically, these tumors appear to be benign. We report on five more such cases in which we investigated the contents of estrogen and progesterone receptors in the pulmonary tumors by immunohistological procedures. All the lung tumors exhibited a high content of progesterone receptors, and in 4 out of the 5 cases a high estrogen receptor content was also found. Modern immunohistological techniques permit the investigation of routinely fixed tissue blocks, and it is thus recommended that the contents of these hormone receptors should be determined in well differentiated, leiomyomatous lung tumors from women. This would both provide information on the pathogenesis of these tumors and establish a basis for possible later institution of hormone treatment. It is likely that the majority of these lung tumors are in fact metastases of extremely well differentiated leiomyosarcomas of the uterus. The possibility that lung tumors of this type may constitute a small group that develop in situ as hormone-sensitive proliferations cannot, however, be fully excluded.

Progesterone receptor A and B protein expression in human breast cancer

The human progesterone receptor (PR) is a ligand-activated nuclear transcription factor which mediates progesterone action in target tissues. Two PR proteins, PR A (81–83 kDa) and PR B (116–120 kDa), have been described and different physiological activities ascribed to each on the basis of in vitro studies, suggesting that their ratio of expression may control progesterone responsiveness in target cells. Presence of PR in breast tumors is an important indicator of likely responsiveness to endocrine agents. However, the relative expression of PR A and B in breast cancer has not been described and its clinical significance has not been addressed. We have examined the expression of PR A and B in PR-positive breast tumors and found that while in most tumors PR A and B were expressed in similar amounts there was a broad overall distribution of PR A:B ratios which deviated significantly from a normal log distribution with tumors containing a PR A:B ratio greater than 4 being over-represented in the group. Linear regression analysis revealed that high PR A:B ratios, in general, derived from a low concentration of PR B rather than high expression of PR A. PR A:B protein ratios were not correlated with the age of the patient or with total PR concentration. A third PR protein band (PR 78 kDa) was detected which comprised greater than 20% of total PR protein in a quarter of the tumor samples examined. The characteristics of tumors containing PR 78 kDa were not different from the overall group. In summary, in PR-positive breast tumors the ratio of expression of PR A and B proteins is close to unity as is seen in a number of other progestin target tissues. However, a significant proportion of tumors expressed very low levels of PR B and a consequently high PR A:B ratio. Although the clinical consequence of this observation is not known, the in vitro findings that PR A may act as a repressor of PR B suggests that tumors containing primarily PR A may identify a subset of patients with low or aberrant response to endocrine agents.

Loss of heterozygosity on chromosome 9 in human breast cancer: Association with clinical variables and genetic changes at other chromosome regions

Primary breast tumors were tested for loss of heterozygosity (LOH), on chromosome 9p with microsatellite markers restricted to a 28 cM region including the MTS1 gene. LOH was found with at least 1 marker in 38% of the 201 cases analyzed. A high frequency of deletions was detected at the 9p23-p21 region, indicating a tumor suppressor gene(s) important for breast cancer tumorigenesis. Tumors with and without LOH on 9p were compared with respect to clinico-pathological factors using chi 2 analysis. Tumors with 9p LOH were significantly associated with high S-phase status and aneuploidy, but not with type, node status, estrogen and progesterone receptor content or age of the patients at diagnosis. Survival analysis showed that LOH at 9p did not significantly affect the survival rate of breast cancer patients. Our results indicate that the aberrations on 9p detected in this study are not of independent prognostic value. A significant association was found between LOH at 9p and LOH at chromosomal arms 3p and 6q, which is an additional contribution toward understanding the genetic events in breast tumor pathogenesis.

Influence of tumour oestrogen concentration on prognosis in breast cancer: studies in pre- and post-menopausal patients of different ethnic groups

Summary Epidemiologic and clinical evidence suggest that oestrogens play a role in sustaining and promoting breast cancer. The relationship of tumour oestrogen levels and other features of breast cancer is, however, poorly understood. The present study included 108 patients with primary breast cancer who had tumour oestrone (E1) and oestradiol (E2) as well as oestrogen and progesterone receptors and aromatization capacity measured. The patient population included both pre- and post-menopausal women and comprised both black and Caucasian subjects. Tumour oestrogen concentrations were significantly lower in premenopausal as compared to post-menopausal patients while E2 measurements were higher in premenopausal as compared to post-menopausal patients. There was no significant correlation between either tumour oestrogen level and hormone receptor status. Tumour oestrogen and progesterone receptor concentrations as well as tumour E1 concentrations were lower in black post-menopausal patients as compared to those found in white post-menopausal patients. In a multivariate analysis both disease free and overall survival were significantly lower in patients with higher tumour E1 levels. Other factors of prognostic significance were race, tumour size (T) and nodal status (N). These findings suggest that tumour hormone content may influence the behaviour of breast cancer independantly of hormone receptor status.