RESUMO
The aim of this study was to identify the expression, cellular localization and regulation of classic estrogen receptors ERα and ERß, ER-α36 isoform and GPER in the androgen-independent prostate cancer cell line PC-3. In addition, we evaluated the relative contribution of these receptors to the activation of the ERK1/2 (extracellular signal-regulated protein kinases) signaling pathway. These four estrogen receptors were detected by Western blot assays and were shown by immunofluorescence assays to localize preferentially in extranuclear regions of PC-3 cells. In addition, treatment with 17ß-estradiol (E2) (1 µM) for 24 h led to down-regulation of the classic estrogen receptors, whereas E2 at physiological concentration (0.1 nM) for 24h tended to increase the levels of ERα and ERß. Furthermore, the ERα-selective agonist PPT selectively increased the expression of ERß and the ERß-selective agonist DPN increased ERα levels. None of these treatments affected expression of the ER-α36 isoform. The unusual cytoplasmic localization of the classic estrogen receptors in these cells differs from the nuclear localization in the majority of estrogen target cells and suggests that rapid signaling pathways may be preferentially activated. In fact, treatment with selective agonists of ERα, ERß and GPER induced ERK1/2 phosphorylation that was blocked by the respective antagonists. On the other hand, activation of ERK1/2 induced by E2 may involve additional mechanisms because it was not blocked by the three antagonists. Taken together, the results indicate that there is a crosstalk between ERα and ERß to regulate the expression of each other, and suggest the involvement of other receptors, such as ER-α36, in the rapid ERK1/2 activation by E2. The identification of new isoforms of ERs, regulation of the receptors and signaling pathways is important to develop new therapeutic strategies for the castration-resistant prostate cancer.
Assuntos
Estradiol/farmacologia , Receptor alfa de Estrogênio/biossíntese , Receptor beta de Estrogênio/biossíntese , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Proteínas de Neoplasias/biossíntese , Neoplasias da Próstata/metabolismo , Linhagem Celular Tumoral , Receptor alfa de Estrogênio/genética , Receptor beta de Estrogênio/genética , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/genética , Masculino , Proteínas de Neoplasias/genética , Neoplasias da Próstata/genéticaRESUMO
BACKGROUND: Intragastric or intraperitoneal ethanol (EtOH) treatment inhibits reproductive functions in females and male rats. The area of the hypothalamus where these effects take place is unknown. As the participations of the preoptic-anterior hypothalamic area (POA-AHA) in regulating ovulation is asymmetric, this study aims to analyze the effects on 17ß-estradiol(E2 ), progesterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH) serum levels, the messenger ribonucleic acid (mRNA) expression of estrogen receptor alpha (ERα) and beta (ERß), and ovulation resulting from unilaterally microinjecting water or an EtOH solution into either side of the POA-AHA. METHODS: The treatment consisted of microinjecting a 8.6 µM EtOH solution into either side of the POA-AHA. The study was performed on groups of adult cyclic rats at 09.00 hours on diestrus-1, and sacrificed on diestrus-2 at 13.00, on proestrus at 09.00 or 17.00 or on estrus at 09.00 hours. Ovulation rates were assessed in rats sacrificed on estrus. Hormonal serum levels were measured using radioimmunoassay, and as a function of ERα and ERß mRNA expression in each side of the POA-AHA by reverse transcriptase polymerase chain reaction. RESULTS: EtOH treatment blocked ovulation and the preovulatory release of LH, and lowered E2 levels. Irrespective of the treated POA-AHA side, ERα mRNA expression was consistently lower in the left POA-AHA and higher on the right. EtOH treatment in the left POA-AHA decreased FSH serum levels and lowered ERß mRNA expression. In turn, EtOH treatment on the right POA-AHA resulted in higher FSH levels and ERß mRNA expression. CONCLUSIONS: The present results show that EtOH blocks the preovulatory surge of LH on the POA-AHA. The effects of EtOH treatment of preovulatory FSH surge on the POA-AHA are asymmetric (stimulative on the right and inhibiting in the left). The effects of EtOH treatment on preovulatory LH and FSH surge could be explained by the inhibition of ERα and ERß mRNA expression, respectively.
Assuntos
Núcleo Hipotalâmico Anterior/efeitos dos fármacos , Etanol/farmacologia , Ovulação/efeitos dos fármacos , Área Pré-Óptica/efeitos dos fármacos , Animais , Núcleo Hipotalâmico Anterior/fisiologia , Estradiol/sangue , Receptor alfa de Estrogênio/biossíntese , Receptor beta de Estrogênio/biossíntese , Etanol/administração & dosagem , Feminino , Hormônio Foliculoestimulante/sangue , Hormônio Luteinizante/sangue , Microinjeções , Área Pré-Óptica/fisiologia , Progesterona/sangue , Ratos , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Estrogen regulates reproductive behavior and drives the proliferation and differentiation of several cell types. These physiological functions of estrogen are mediated by estrogen receptors (ERs), and each ER isoform plays a distinct role. To clarify the molecular mechanism of estrogen action and to evaluate the effect of ERs on the secretion of ovalbumin (OVA) in pigeon oviduct epithelial cells (POECs), we determined the complete coding sequences encoding ER alpha (ERα) and ER beta (ERß) in pigeons. The abundance of pigeon ERα and ERß mRNA was detected using quantitative polymerase chain reaction. These results revealed that pigeon ERα is highly expressed in the oviduct, while pigeon ERb is highly expressed in the ovary and kidney. We hypothesize that ERα mRNA predominates over that of ERß in the oviduct. The expression of ERα can be down-regulated by 17ß-estradiol, and the knockdown of ERα promoted OVA mRNA expression in cultured POECs, indicating that ERα may play an important role in OVA secretion.
Assuntos
Células Epiteliais/metabolismo , Receptor alfa de Estrogênio/genética , Receptor beta de Estrogênio/genética , Animais , Clonagem Molecular , Columbidae/genética , Estradiol/metabolismo , Receptor alfa de Estrogênio/biossíntese , Receptor beta de Estrogênio/biossíntese , Feminino , Expressão Gênica , Oviductos/metabolismo , RNA Mensageiro/biossínteseRESUMO
OBJECTIVE: To determine changes in morphometry and expression of oestrogen receptors (OR) in the pubococcygeus and bulbospongiosus muscles, and the concentration of serum oestradiol associated with multiparity. STUDY DESIGN: Twelve chinchilla-breed female rabbits were divided into multiparas who had undergone four consecutive deliveries and age-matched virgin nulliparas. Pubococcygeus and bulbospongiosus muscles were surgically removed from each rabbit and processed histologically. Fibre cross-sectional area, number of peripheral nuclei, and expression of ORα and ORß were measured for each muscle. Serum samples were obtained and the concentration of serum oestradiol was quantified. RESULTS: Multiparity increased (p ≤ 0.05) fibre cross-sectional area and the number of peripheral nuclei per fibre in pubococcygeus muscle, but not in bulbospongiosus muscle. Expression of both ORα and ORß was high (p ≤ 0.05) in both muscles from multiparous rabbits. A rise in serum oestradiol was measured at the end of the second pregnancy, which was absent (p ≤ 0.05) at the end of the fourth pregnancy. The concentration of serum oestradiol was similar (p > 0.05) in nulliparous and multiparous rabbits. CONCLUSIONS: Multiparity caused morphometric changes in pubococcygeus muscle but not in bulbospongiosus muscle. As OR expression was high for both muscles, some properties related to fibre composition or muscle physiology could be affected. The finding that serum oestradiol was not elevated at the end of the fourth pregnancy could be related to changes in pelvic and perineal muscles associated with multiparity.
Assuntos
Estradiol/sangue , Receptor alfa de Estrogênio/biossíntese , Receptor beta de Estrogênio/biossíntese , Músculo Esquelético/fisiologia , Paridade/fisiologia , Prenhez/fisiologia , Animais , Feminino , Fibras Musculares Esqueléticas/ultraestrutura , Músculo Esquelético/ultraestrutura , Gravidez , CoelhosRESUMO
Recently, the effects of extremely low-frequency electromagnetic fields (ELF EMF) on biological systems have been extensively investigated. In this report, the influence of ELF EMF on olfactory bulb (OB) estrogen receptor-alpha (ER alpha) mRNA and -beta (ER beta) mRNA expression was studied by RT-PCR in adult female and male rats. Results reveal for the first time that ELF EMF exerted a biphasic effect on female OB ER beta mRNA gene expression, which increased during diestrous and decreased during estrous. We did not observe any influence of ELF EMF on female OB ER alpha mRNA expression. Our data demonstrate a fluctuating pattern of ER-alpha and -beta mRNA expression in the female OB throughout the phases of the estrous cycle in non-ELF EMF-exposed animals. Thus the highest ER alpha expression was observed in diestrous and the lowest in proestrous. The pattern of ER beta mRNA was less variable, the lowest expression was observed in diestrous. ER-alpha mRNA and -beta mRNA expression level in the male OB did not exhibit any variation either in ELF EMF-exposed or non-ELF EMF-exposed animals. In summary, ELF EMF modulate ER beta gene expression in the OB of female adult rats but not in males.
Assuntos
Campos Eletromagnéticos , Receptor alfa de Estrogênio/biossíntese , Receptor beta de Estrogênio/biossíntese , Memória/efeitos da radiação , Bulbo Olfatório/metabolismo , Reconhecimento Psicológico/efeitos da radiação , Comportamento Social , Animais , Ciclo Estral , Feminino , Masculino , Ratos , Ratos Wistar , Fatores SexuaisRESUMO
Adrenarche is a process of postnatal sexual maturation occurring in higher primates, in which there is an increase in the secretion of adrenal androgens. It is the consequence of a process of postnatal organogenesis characterized by the development of a new zone in the adrenal cortex, the zona reticularis (ZR). The mechanism of this phenomenon remains poorly understood, suggesting that it might be a multifactorial event. A relationship between circulating IGF-I, insulin sensitivity, and adrenal androgens has been postulated. Boys and girls have different patterns of changes in insulin sensitivity at puberty, perhaps secondary to differences in the estrogen milieu. Estrogen effects may also play a role in premature adrenarche. Peripheral or local IGF-1 actions could regulate adrenal progenitor cell proliferation and migration. Since adrenal progenitor cells as well as IGF-I and the IGF-R1 are located in the outer zone of the adrenal cortex during childhood and adolescence, this peripheral cell layer, below the capsule, may contain undifferentiated progenitor cells. Therefore, the IGF-R1 signaling pathway might positively modulate the proliferation and migration of adrenal progenitor cell to stimulate the development of adrenal zones, including ZR. However, no evidence of a direct action of IGF-I on ZR was found. In addition, a role for estrogens in the ontogenesis of ZR is suggested by the presence of aromatase (CYP19) in the subcapsular zona glomerulosa and in the adrenal medulla. Estrogens produced locally could act on ZR by interacting with estrogen receptor beta (ERbeta), but not alpha, and membrane estrogen receptor GPR-30. An estradiol-induced increase in DHEA/cortisol ratio was indeed seen in cultures of adrenocortical cells from post-adrenarche adrenals. In summary, several lines of evidence point to the action of multiple factors, such as local adrenal maturational changes and peripheral metabolic signals, on postnatal human adrenal gland ZR formation.
Assuntos
Glândulas Suprarrenais/crescimento & desenvolvimento , Glândulas Suprarrenais/metabolismo , Adrenarca/fisiologia , Somatomedinas/biossíntese , Adolescente , Aromatase/biossíntese , Criança , Pré-Escolar , Sulfato de Desidroepiandrosterona/sangue , Receptor alfa de Estrogênio/biossíntese , Receptor beta de Estrogênio/biossíntese , Feminino , Humanos , Lactente , Recém-Nascido , Insulina/fisiologia , Fator de Crescimento Insulin-Like I/metabolismo , Masculino , Puberdade/fisiologia , RNA Mensageiro/metabolismo , Receptor IGF Tipo 1/biossíntese , Receptores de Estrogênio , Receptores Acoplados a Proteínas G/biossínteseRESUMO
Expression of estrogen receptors (ER) is clinically relevant in designing therapeutic strategies. The relative importance of the two types of estrogen receptors (ER-alpha and ER-beta) in human breast cancers in pre- and post-menopausal women has not been properly defined. To determine the possible association between the expression of estrogen receptor and serum estradiol levels in pre- and post-menopausal women with breast cancer. 44 patients with invasive ductal carcinoma of the breast were studied and a breast tissue biopsy was taken. ER-alpha and ER-beta were detected by immunocytochemistry. Serum levels of estradiol and estrone were measured by radioimmunoassay and FSH was measured using IRMA. We studied 21 pre- and 23 post-menopausal women with breast carcinoma. Examining the number of cases with tumors positive for ER, we found no differences in the frequency of ER-alpha between pre- and post-menopausal women, but ER-beta decreased marginally after menopause (p < 0.051). In cases with tumors positive for ER, the proportion of cells positive for ER-alpha was similar post-menopausally (53.95%) and pre-menopausally (57.21%), but for ER-beta the number of positive cells decreased significantly after menopause (p < 0.051). In pre-menopausal women there was a correlation between serum estradiol levels and ER-beta; in post-menopausal women there was a correlation between serum FSH levels and ER-alpha. These results indicate that estradiol levels in women with mammary carcinoma are related to ER-beta expression in the breast tumor tissue.
Assuntos
Neoplasias da Mama/metabolismo , Carcinoma Ductal de Mama/metabolismo , Receptor alfa de Estrogênio/biossíntese , Receptor beta de Estrogênio/biossíntese , Pós-Menopausa/metabolismo , Pré-Menopausa/metabolismo , Adulto , Estradiol/sangue , Feminino , Hormônio Foliculoestimulante/sangue , Humanos , Imuno-Histoquímica , Pessoa de Meia-Idade , RadioimunoensaioRESUMO
OBJECTIVE: To study if the endocrinological status of PCOS women affects the endometrial sensitivity to steroids by evaluating the expression of androgen receptor (AR), estrogen receptor alpha (ERalpha), estrogen receptor beta (ERbeta), co-activators AIB1 and ARA70, and co-repressor NCoR. METHODS: Gene and/or protein expression of steroid receptors and co-regulators was measured in 17 samples of normal endometrium (NE), 23 PCOS endometrium without treatment (PCOSE), 11 endometria from PCOS women and with endometrial hyperplasia (HPCOSE), and 10 endometria from patients with endometrial hyperplasia (HE), using RT-PCR and/or immunohistochemistry and Western blot. RESULTS: Gene and protein expression of AR was relatively elevated in PCOSE and HPCOSE compared with NE. A significant increase in ERalpha protein expression was observed in PCOSE, preferentially in the nucleus of endometrial cells, whereas ERbeta gene and protein expression increased gradually from PCOSE to HPCOSE and HE, mainly in the epithelial compartment. Importantly, we found a gradual increase in the ERbeta/ERalpha gene and protein expression ratio in endometria from the four groups of women. AIB1 showed increased nuclear protein expression in PCOSE compared to NE, in the presence of a high expression of ARA70 in all groups. High expression of ARA70 together with a normal expression level of AIB1 was observed in HPCOSE. The cytoplasmic immunostaining of NCoR was similar between the four groups of patients. CONCLUSION: The PCOS endometrium exhibits a higher sensitivity to steroid action. We can inferred that these alterations could deregulate the transcription of genes involved in the cell cycle, which may lead to the development of endometrial hyperplasia in PCOS women.
Assuntos
Hiperplasia Endometrial/metabolismo , Histona Acetiltransferases/biossíntese , Proteínas Nucleares/biossíntese , Proteínas Oncogênicas/biossíntese , Síndrome do Ovário Policístico/metabolismo , Receptores Androgênicos/biossíntese , Receptores de Estrogênio/biossíntese , Proteínas Repressoras/biossíntese , Transativadores/biossíntese , Fatores de Transcrição/biossíntese , Adulto , Hiperplasia Endometrial/complicações , Hiperplasia Endometrial/genética , Endométrio/metabolismo , Receptor alfa de Estrogênio/biossíntese , Receptor alfa de Estrogênio/genética , Receptor beta de Estrogênio/biossíntese , Receptor beta de Estrogênio/genética , Feminino , Expressão Gênica , Histona Acetiltransferases/genética , Humanos , Proteínas Nucleares/genética , Correpressor 1 de Receptor Nuclear , Coativador 3 de Receptor Nuclear , Coativadores de Receptor Nuclear , Proteínas Oncogênicas/genética , Síndrome do Ovário Policístico/complicações , Síndrome do Ovário Policístico/genética , Receptores Androgênicos/genética , Receptores de Estrogênio/genética , Proteínas Repressoras/genética , Transativadores/genética , Fatores de Transcrição/genética , Transcrição GênicaRESUMO
The aim of this study was to examine, using semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) the changes in mRNA expression of the two estrogen receptor (ER) subtypes, ERalpha and ERbeta, prolactin receptor long and short form, and progesterone (Pg) receptor (PgR), in liver and mammary gland during gestation, early lactation, and weaning in both hyperthyroid (HT) and normal rats. Pregnancy increased long prolactin receptors (PRL-R(L)) and ERalpha mRNAs in liver and PRL-R(I) in mammary gland. Lactation decreased PRL-R(L) in liver and ERbeta and PgR in mammary gland. HT decreased PRL-R(L), at the end of pregnancy (G21), ERalpha (in G21 and L1) in liver and PRL-R(L) in L1 as well as short prolactin receptors (PRL-R(S)) (G7, L1) and ERbeta (G7, G14, L4) in mammary gland. In conclusion, our data indicated that (1) PRL-R1 and ERalpha expression levels are differentially regulated in the liver, and PgR and ERbeta in mammary gland during pregnancy and lactation (2) ERbeta is variably expressed depending on the state of thyroid hormones, however the ERalpha gene expression remained constant in mammary gland. (3) PRL-R1 mRNA expression is highly induced in the mammary gland during late pregnancy and abruptly declines on the first day of lactation for the HT rats.