Role Of Estrogen Receptor Beta Research Articles

Estrogen receptor beta is not increasingly expressed in leiomyoma nodules which show no progressive enlargement in premenopausal women.

Studies on the expression of estrogen receptors (ERs) in uterine leiomyomata have yielded conflicting results. A controlled study focusing on leiomyomal nodules with same clinical presentations and hormonal milieu was conducted to investigate the role of ER beta (ERbeta) on leiomyomal growth. Thirty pairs of leiomyomal and myometrial tissues were included in the study. The specimens were obtained from 30 premenopausal women (40-45 years old) with parity 2, and were sampled during the proliferative menstrual phase. All of the leiomyomal nodules were unifocal, medium sized (4-5 cm), intramurally located, and without progressive enlargement for 6 months. The expressions of ERbeta mRNA and protein in leiomyomata and their adjacent myometria were analyzed by reverse transcriptase-polymerase chain reaction and immunohistochemistry using ERbeta-specific antibody, respectively. ER alpha (ERalpha) was simultaneously studied using similar methods. The results were digitally quantified and compared with each other. All paired tissues (30/30, 100%) showed a higher ERalpha expression level (paired t test, p < 0.05). In most leiomyomal nodules (27/30, 90%), both ERbeta and ERalpha exhibited no differences in mRNA levels compared to their adjacent myometria (p > 0.05), but the ratio of ERbeta/ERalpha (expression index) was lower (p < 0.05) in leiomyomal tissue. Although the immunoreactivity scores for ERbeta were similar in paired tissues, more ERbeta-positive cells were detected in myometrial specimens than in their leiomyoma counterparts (mean of 62% vs 56%). Furthermore, the distribution pattern of ERbeta in leiomyoma (nuclear and cytoplasmic) was different from that in the corresponding myometrium (nuclear). The lower ERbeta/ERalpha expression index in stationary leiomyoma suggests that the relative abundance of ERbeta and ERalpha, rather than their individual amounts, determines the existence and development of leiomyoma. This study demonstrated that in premenopausal women, ERbeta is not increasingly expressed in the leiomyomal nodules which show no progressive enlargement. The distinctive ERbeta-to-ERalpha ratio rather than their individual amounts, is associated with the stationary status of the leiomyomal nodule.

Estrogen Receptor Beta (ESR2) Polymorphisms in Familial and Sporadic Breast Cancer

Estrogen is involved in both normal mammary development and in breast carcinogenesis. A family history of disease and exposure to estrogen are major risk factors for developing breast cancer. Estrogen exerts its biological effects through binding to the estrogen receptors, estrogen receptor alpha (ESR1) and the more recently discovered estrogen receptor beta (ESR2). Genetic variation in genes involved in estrogen biosynthesis, metabolism and signal transduction have been suggested to play a role in breast cancer risk. We therefore tested the hypothesis that common genetic variants of the ESR2 gene may be associated with increased risk for breast cancer and this risk may vary between breast cancer groups. We investigated three common ESR2 polymorphisms, rs1256049 (G1082A), rs4986938 (G1730A) and rs928554 (Cx+56 A-->G) for association to breast cancer risk. A total of 723 breast cancer cases and 480 controls were included in the study. Of the breast cancer cases, 323 were sporadic and 400 were familial, the familial cases were further divided into familial high-risk and familial low-risk breast cancer cases. We found no overall statistically significant association for any of the single polymorphisms studied. Haplotype analysis suggested one haplotype associated with increased risk in sporadic breast cancer patients (OR = 3.0, p = 0.03). Further analysis is needed to elucidate the role of estrogen receptor beta in breast cancer susceptibility.

Effect of Ovariectomy on Adipose Tissue of Mice in the Absence of Estrogen Receptor Alpha (ERα): a Potential Role for Estrogen Receptor Beta (ERβ)

Effect of Ovariectomy on Adipose Tissue of Mice in the Absence of Estrogen Receptor Alpha (ERα): a Potential Role for Estrogen Receptor Beta (ERβ)

Effect of Ovariectomy on Adipose Tissue of Mice in the Absence of Estrogen Receptor Alpha (ERα): a Potential Role for Estrogen Receptor Beta (ERβ)

Effect of Ovariectomy on Adipose Tissue of Mice in the Absence of Estrogen Receptor Alpha (ERα): a Potential Role for Estrogen Receptor Beta (ERβ)

Estrogen receptor beta is expressed in human stomach adenocarcinoma.

In stomach adenocarcinoma, the role of the hormonal receptor, estrogen receptor (ER), has been controversial. Recently, a new estrogen receptor, called estrogen receptor beta (ER beta), was found to be expressed in various tissues including normal gastrointestinal tract. In this paper, the expression of ER beta in stomach adenocarcinomas has been investigated for the first time, specifically in signet ring cell adenocarcinomas, together with surrounding non-cancerous tissues. By immunohistochemistry the expression of ER alpha and beta was studied in 29 stomach adenocarcinomas, ten signet ring cell adenocarcinomas, and 19 other adenocarcinomas. Western blotting was performed to examine the immunohistochemical result. Statistical studies (Student's t test and chi(2)-test) explored the relation between the immunohistochemical result and clinicopathological characteristics. All 29 adenocarcinomas, including the signet ring cell ones, demonstrated clear ER beta nucleus staining. Lymphocytes, venous endothelial cells, smooth muscle, and non-cancerous stomach glands also showed strong ER beta staining, while no staining was observed in the immunohistochemistry of ER alpha. Western blotting showed equivalent ER beta protein levels in cancerous and non-cancerous tissues, which was consistent with the results of immunohistochemical staining. Among signet ring cell adenocarcinomas of the stomach, cytoplasm were stained in addition to nuclei, specifically in patients under the age of 40 years. Our results imply that the effects of estrogen in stomach cancer, as well as those in normal stomach, may be mediated by ER beta, and that the role of ER beta may differ by the subtype of stomach adenocarcinoma - specifically signet ring cell adenocarcinomas and other ones - although large scale samples are needed to confirm these findings.

Role of estrogen receptor beta in estrogen action.

There was a time when the classification of sex hormones was simple. Androgens were male and estrogens female. What remains true today is that in young adults androgen levels are higher in males and estrogen levels higher in females. More recently we have learned that estrogens are necessary in males for regulation of male sexual behavior, maintenance of the skeleton and the cardiovascular system, and for normal function of the testis and prostate. The importance of androgen in females was never in doubt, it is after all the precursor of estrogen as the substrate for aromatase, the enzyme that produces estrogen. In addition, the tissue distribution of androgen receptors suggests that androgens themselves are important in the ovary, uterus, breast, and brain. New information promises to clarify some of the complex issues of the physiological roles of estrogen and the contribution of estrogen to the development of neoplastic diseases in humans. The discovery of the second estrogen receptor, the creation of mutant mice defective in both estrogen receptors and in the aromatase gene, the solution of the structures of the ligand-binding domains of estrogen receptor alpha (ERalpha) and estrogen receptor beta (ERbeta), the finding of novel routes through which estrogen receptors can modulate transcription, and the identification of a man with a bi-allelic disruptive mutation of the ERalpha gene are but some of the milestones. This review focuses on the mechanistic aspects of signal transduction mediated by ERs and on the physiological consequences of deficiency of estrogen or estrogen receptor in the available mouse models.

Expression of oestrogen receptor alpha and beta mRNA in corpus luteum of human subjects.

To investigate the role of oestrogen receptor beta (ERbeta) in the function of human ovarian corpus luteum, the levels of luteal ERalpha and ERbeta mRNA were determined using competitive reverse transcription-polymerase chain reaction-Southern blot analysis. The expression of ERalpha and ERbeta mRNA was detected in all luteal samples analysed. Luteal ERalpha and ERbeta mRNA levels were significantly lower (P<0.01 and P<0.05 respectively) at the late secretory phase than those at the early and mid-secretory phases of the endometrium. The ratio of ERalpha to ERbeta mRNA levels showed no change during the secretory phase of the endometrium. This study demonstrates that ERbeta is co-expressed with ERalpha in human corpus luteum and is likely to play a biological role in the regulation of steroidal action of the corpus luteum with ERalpha.