Augmentation of estrogen receptor-mediated transcription by steroid and xenobiotic receptor

Clinical features, presentation and hormonal parameters in patients with pubertal gynecomastia

Objective:

Gynecomastia is benign enlargement of breast in male. It is postulated that its development is primarily due to a mismatch in ratio of oestrogen and androgen at breast tissue. The aim of this study was to highlight the clinical features, presentation and hormonal parameters at the time of consultation.

Methods:

All adolescent patients who attended endocrinology department with the complaint of breast enlargement were taken into study. We analysed their thyroid function test, oestrogen, testosterone, prolactin, alpha-fetoprotein, follicle-stimulating hormone, luteinizing hormone, beta HCG (human chorionic gonadotropin) and liver function. Clinical features and anthropometry were recorded.

Results:

Out of 50 patients enrolled, 34 (68%) had bilateral gynaecomastia while 16 patients (32%) had unilateral disease. Mastalgia was seen in 44 patients (88%). Psychological disturbance in the form of depression was seen in 60% of adolescent boys with gynecomastia. Tanner stage B had positive correlation with oestrogen to testosterone (E2/TTE) ratio (r = 0.47; P = 0.034). All other hormonal parameters were normal.

Conclusion:

Mastalgia was one of the presenting complaints in majority of patients and many had bilateral enlargement. Altered oestrogen to testosterone ratio is altered in majority of patients thus may be reason for pubertal gynecomastia.

Clinical and Biochemical Phenotype of Adolescent Males with Gynecomastia

OBJECTIVE

Gynecomastia is defined as a benign proliferation of male breast glandular tissue. Its prevalence during puberty varies between 50-60% and is also common in neonatal and elderly males. It develops mainly due to the disequilibrium between estrogen and androgen activity in breast tissue, where estradiol (E2) binds to estrogen receptors and stimulates ductal and glandular cells. The aim of this work was to investigate the relationship between sex hormone alterations and the natural history of gynecomastia.

METHODS

Participants in this study were young males referred to an outpatient clinic, between January 2011 and February 2016, with breast enlargement. Thyroid function, liver function, hormone concentrations and tumor markers were measured and anthropometric assessment was conducted.

RESULTS

Subjects comprised 93 males, aged 9 to 18 (mean±standard deviation age 13.8±2.6) years. In 63 of 93 (67.7%) the gynecomastia was confirmed and 28 were followed-up for a median period of three months. None of the boys showed any reduction in breast size during follow-up. There was no correlation between body mass index Z-score and breast size. Breast enlargement progressed in nine boys (32.1%). A positive correlation between estrogen to testosterone (E2/TTE) ratio and Tanner B stage (r=0.47; p=0.034) was observed.

CONCLUSION

The E2/TTE ratio may be a helpful tool in diagnosing gynecomastia. Altered E2/TTE ratio might be responsible for a proportion of cases described previously as idiopathic. Additionally, weight loss does not imply reduction of breast size in boys. Nonetheless it should be the first step in the management of prolonged gynecomastia.

Gynecomastia and hormones

Gynecomastia-the enlargement of male breast tissue in men-is a common finding, frequently observed in newborns, adolescents, and old men. Physiological gynecomastia, occurring in almost 25 % of cases, is benign and self-limited; on the other hand, several conditions and drugs may induce proliferation of male breast tissue. True gynecomastia is a common feature often related to estrogen excess and/or androgen deficiency as a consequence of different endocrine disorders. Biochemical evaluation should be performed once physiological or iatrogenic gynecomastia has been ruled out. Non-endocrine illnesses, including liver failure and chronic kidney disease, are another cause of gynecomastia which should be considered. Treating the underlying disease or discontinuing medications might resolve gynecomastia, although the psychosocial burden of this condition might require different and careful consideration.

Estrogen Deficiency and the Origin of Obesity during Menopause

Sex hormones strongly influence body fat distribution and adipocyte differentiation. Estrogens and testosterone differentially affect adipocyte physiology, but the importance of estrogens in the development of metabolic diseases during menopause is disputed. Estrogens and estrogen receptors regulate various aspects of glucose and lipid metabolism. Disturbances of this metabolic signal lead to the development of metabolic syndrome and a higher cardiovascular risk in women. The absence of estrogens is a clue factor in the onset of cardiovascular disease during the menopausal period, which is characterized by lipid profile variations and predominant abdominal fat accumulation. However, influence of the absence of these hormones and its relationship to higher obesity in women during menopause are not clear. This systematic review discusses of the role of estrogens and estrogen receptors in adipocyte differentiation, and its control by the central nervous systemn and the possible role of estrogen-like compounds and endocrine disruptors chemicals are discussed. Finally, the interaction between the decrease in estrogen secretion and the prevalence of obesity in menopausal women is examined. We will consider if the absence of estrogens have a significant effect of obesity in menopausal women.

Interaction of silencing mediator for retinoid and thyroid receptors with steroid and xenobiotic receptor on multidrug resistance 1 promoter

AIMS

The steroid and xenobiotic receptor (SXR) regulates the transcription of its target genes by interacting with various nuclear receptor cofactors. We have previously shown that silencing mediator for retinoid and thyroid receptors (SMRT) interacts with SXR even in the presence of rifampicin on cytochrome P450 monooxygenase 3A4 (CYP3A4) promoter in HepG2 cells. To examine the specificity of such interaction, the involvement of SMRT on SXR-mediated transcription through multidrug resistance (MDR) 1 gene promoter was examined using LS174T intestine-derived clonal cells.

MAIN METHODS

Transient transfection-based reporter gene assay was carried out to examine the effect of SMRT or nuclear receptor corepressor (NCoR) on SXR-mediated transcription in LS174T cells. Semi-quantitative RT-PCR was performed to confirm the expression of MDR1 mRNA in LS174T cells. To examine the interaction of SMRT with SXR, we carried out mammalian one-hybrid assay in CV-1 cells and immunoprecipitation study in HEK-293 cells.

KEY FINDINGS

SMRT, but not NCoR suppressed rifampicin-induced SXR-mediated transcription. The SXR-mediated MDR1 mRNA expression was augmented in the presence of rifampicin, whereas it suppressed the expression following the overexpression of SMRT. In mammalian one-hybrid assay, only SMRT but not NCoR interacted with SXR on MDR1 promoter in the presence of rifampicin. In immunoprecipitation study, SMRT bound to SXR regardless of the presence or absence of rifampicin.

SIGNIFICANCE

SMRT may be recruited in the SXR-cofactor complex even in the presence of ligand. SMRT may be involved not only in SXR-mediated suppression without ligand, but also in ligand-activated transcription to suppress the overactivation of transcription.

Steroid and Xenobiotic Receptor (SXR) as a possible prognostic marker in epithelial ovarian cancer

We examined the expression of the steroid and xenobiotic receptor (SXR) and evaluated its clinical significance in human epithelial ovarian carcinoma. One hundred forty-one cases were examined using immunohistochemistry for SXR with archival specimens. All cases were scored using a semi-quantitative histological scoring (HSCORE) method. Specimens with an HSCORE > 60 were regarded as SXR-positive. Various clinicopathologic variables were examined. SXR showed significant differences in age, histology, grade, ER alpha and PR. SXR was detected in 35 of 141 (24.8%) ovarian cancer tissues. There was a statistically significant negative correlation between SXR-positive status and both disease-free survival and overall survival (P= 0.0415 and 0.0316, respectively), independent of stage (P= 0.0167 and 0.021, respectively). In multivariate analysis, SXR was a statistically independent risk factor for both disease-free survival and overall survival (P= 0.049 and 0.0354). Our results support an association of SXR between ER alpha and PR in epithelial ovarian cancers. Our data suggest that SXR is a prognostic factor in epithelial ovarian cancer and may represent a useful marker to identify patients at risk of recurrence or death.

Elucidating the 'Jekyll and Hyde' nature of PXR: the case for discovering antagonists or allosteric antagonists

The pregnane X receptor belongs to the nuclear hormone receptor superfamily and is involved in the transcriptional control of numerous genes. It was originally thought that it was a xenobiotic sensor controlling detoxification pathways. Recent studies have shown an increasingly important role in inflammation and cancer, supporting its function in abrogating tissue damage. PXR orthologs and PXR-like pathways have been identified in several non-mammalian species which corroborate a conserved role for PXR in cellular detoxification. In summary, PXR has a multiplicity of roles in vivo and is being revealed as behaving like a "Jekyll and Hyde" nuclear hormone receptor. The importance of this review is to elucidate the need for discovery of antagonists of PXR to further probe its biology and therapeutic applications. Although several PXR agonists are already reported, virtually nothing is known about PXR antagonists. Here, we propose the development of PXR antagonists through chemical, genetic and molecular modeling approaches. Based on this review it will be clear that antagonists of PXR and PXR-like pathways will have widespread utility in PXR biology and therapeutics.