• Animal cells and systems
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• v.10 no.3
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• pp.115-120
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• 2006

Parkinson's disease (PD) is a neurodegenerative disease caused by selective degeneration of dopaminergic neurons in the substantia nigra. Mutations in ${\alpha}$-synuclein have been causally linked to the pathogenesis of hereditary PD. In addition, it is a major component of Lewy body found in the brains of sporadic cases as well. In the present study, we examined whether overexpression of wild type or PD-related mutant ${\alpha}$-synuclein induces unfolded protein response (UPR) and triggers the known signaling pathway of the resulting endoplasmic reticulum (ER) stress in SH-SY5Y cells. Overexpression of wild type, A30P, and A53T ${\alpha}$-synuclein all induced XBP-1 mRNA splicing, one of the late stage UPR events. However, activation of ER membrane kinases and upregulation of ER or cytoplsmic chaperones were not detected when ${\alpha}$-synuclein was overexpressed. However, basal level of cytoplsmic calcium was elevated in ${\alpha}$-synuclein-expressing cells. Our observation suggests that overexpression of ${\alpha}$-synuclein induces UPR independent of the known ER membrane kinase-mediated signaling pathway and induces ER stress by disturbing calcium homeostasis.

• Molecules and Cells
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• v.25 no.2
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• pp.289-293
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• 2008

The role of SPOP in the ubiquitination of $ER{\alpha}$ by the Cullin3-based E3 ubiquitin ligase complex was investigated. We showed that the N-terminal region of SPOP containing the MATH domain interacts with the AF-2 domain of $ER{\alpha}$ in cultured human embryonic 293 cells. SPOP was required for coimmunoprecipitation of $ER{\alpha}$ with Cullin3. This is the first report of the essential role of SPOP in $ER{\alpha}$ ubiquitination by the Cullin3-based E3 ubiquitin ligase complex. We also demonstrated repression of the transactivation capability of $ER{\alpha}$ in cultured mammalian cells.

• Journal of the East Asian Society of Dietary Life
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• v.15 no.3
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• pp.315-322
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• 2005

In this study we report on the estrogen activity of silkworm pupa and herb extracts in vitro. The estrogenic activity of these resources was investigated by competition binding assays with estrogen receptor $\alpha(ER{\alpha})\;or\;ER{\beta}$, and viability of MCF-7 cells, a human breast cancer cell line. Saturation ligand-binding analysis of $ER{\alpha}\;and\;ER{\beta}$ revealed that all plant extracts competed with estrogen ligand for binding to both ER subtypes with a similar preference and degree and competed stronger with ligand for binding to $ER{\beta}\;than\;to\;ER{\alpha}$. The highest $ER{\alpha}-binding$ sample was silkworm pupa aqueous extract The highest $ER{\beta}-binding$ sample was silkworm pupa oil. These samples were further tested for bioactivity based on their ability to regulate cell growth rate in ER(+) breast cancer cell line, MCF-7 cells. Our studies showed that silkworm pupa, soritae, sesame, yam, pueraria, malt, ginseng, Polygonum multiflorum, and Curcuma longa significantly stimulated the growth of MCF-7 cells (P<0.05). In summary, these results suggested that silkworm pupa and herbs might be useful as potential phytoestrogens.

• Journal of Life Science
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• v.12 no.3
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• pp.317-324
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• 2002

We investigated the compositional changes of glycoconjugates (GCs) and expression of estrogen receptor (ER)-$\alpha$, c-fos and c-jun in the vagina of normal and ovariectomized rats by histochemical and immunohistochemical methods. The mucinous transformation of the superficial layer that occurred from late diestrus to proestrus was accompanied with extensive enrichment of GCs. According to the cyclic changes of the vagina, distinct reactivity patterns such as SBA affinity in the diestrus and Con A affinity in the diestrus and estrus phase was observed. However, weak staining for GCs was detected in the atrophied vaginal epithelium of ovariectomized rats. ER-$\alpha$ immunoreaction was mainly demonstrated in the basal layer of epithelium and estrus cycle-related variation in the number of ER-$\alpha$ immunoreaction were not pronounced. But the stromal cells showing ER-$\alpha$ immunoreaction were abundantly observed from diestrus to estrus phase. The most numerous c-fos immunoreactive cells were observed in the basal and intermediate layer of epithelium and stromal fells from the proestrus to estrus phase and c-jun in the basal layer of epithelium during estrus phase. The c-jun immunoreaction of stromal cells expressed only in the estrus phase. In the ovariectomized rats, a few of ER-$\alpha$, c-fos and c-jun immunoreactive cells were observed in the vaginal epithelium and no immunoreaction were found in the stromal cells. ER-$\alpha$ and c-fos immunoreaction fully expressed in the proestrus coincident with the cell proliferation, mutinous transformation and cornification of vaginal epithelium. These data indicate that vagina epithelium and stromal reals express multiple protein such as ER-$\alpha$, c-fos and c-iun by estrogen that may function in process of cells proliferation and differentiation of vagina epithelium.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.4
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• pp.1431-1437
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• 2012

The growth of many breast tumors is stimulated by IGF-1, which activates signal transduction pathways inducing cell proliferation. $ER{\alpha}$ is important in this process. The aim of the study was to investigate relationships in vitro among inhibitory effects of luteolin on the growth of MCF-7 cells, IGF-1 pathway and $ER{\alpha}$. Our results showed that luteolin could effectively block IGF-l-stimulated MCF-7 cell proliferation in a dose- and time-dependent manner and block cell cycle progression and induce apoptosis evidenced by the flow cytometric detection of sub-G1DNA content. Luteolin markedly decreased IGF-l-dependent IGF-IR and Akt phosphorylation without affecting Erk1/2 phosphorylation. Further experiments pointed out that $ER{\alpha}$ was directly involved in IGF-l induced cell growth inhibitory effects of luteolin, which significantly decreased $ER{\alpha}$ expression. Knockdown of $ER{\alpha}$ in MCF-7 cells by an $ER{\alpha}$-specific siRNA decreased the IGF-l induced cell growth inhibitory effects of luteolin. $ER{\alpha}$ is thus a possible target of luteolin. These findings indicate that the inhibitory effect of luteolin on the growth of MCF-7 cells is via inhibiting IGF-l mediated PI3K-Akt pathway dependent of $ER{\alpha}$ expression.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.4
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• pp.510-522
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• 2008

Our earlier studies showed that estrogen was involved in the regulation of fluid reabsorption in adult mouse efferent ductules (ED), through estrogen receptor (ER) ${\alpha}$ and $ER{\beta}$ by modulating gene expression of epithelial genes involved in ion homeostasis. However, little is known about the importance of $ER{\alpha}$ in the ED during postnatal development. Based on previous findings, we hypothesized that there should be a difference in the expression of epithelial ion transporters and anion producers in the ED of postnatal wild type (WT) and estrogen receptor ${\alpha}$ knockout (${\alpha}ERKO$) mice. Using absolute, comparative and semi-quantitative RT-PCR along with immunohistochemistry, we looked at expression levels of several genes in the ED across postnatal development. The presence of estrogen in the testicular fluid was indirectly ascertained by immunohistochemical detection of the P450 aromatase in the testis. There was no immunohistochemically detectable difference in the expression of P450 aromatase in the testes and ER${\beta}$ in the ED of WT and ${\alpha}$ERKO mice. ER${\alpha}$ was only detected in the ED of WT mice. The absence of ER${\alpha}$ in the ED of postnatally developing mice resulted in differential expression of mRNAs and/or proteins for carbonic anhydrase II, $Na^+/H^+$ exchanger 3, down-regulated in adenoma, cystic fibrosis transmembrane regulator, and $Na^+/K^+$ ATPase ${\alpha}$. Our data indicate that the absence of ER${\alpha}$ resulted in altered expression of an epithelial ion producer and transporters during postnatal development of mice. We conclude that the presence of ER${\alpha}$is important for regulation of the ED function during the prepubertal developmental and postpubertal period.

• Journal of Aquaculture
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• v.17 no.1
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• pp.62-68
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• 2004

A cDNA encoding the masu salmon, Oncorhynchus masou, estrogen receptor $\alpha$ (msER$\alpha$) was cloned from the pituitary gland by polymerase chain reaction (PCR). This cDNA contains an open reading frame encoding 513 amino acid residues, and the calculated molecular weight of this protein is about 56,430 Dalton. The amino acid sequences of the DNA binding and ligand binding domains of msER$\alpha$ showed high homology to those of other fish species (84-100%). Reverse transcription PCR analysis showed that the mRNA level of msER$\alpha$ in the pituitary was slightly higher in estradiol-17$\beta$(E2) injected masu salmon than that of control fish. To test the biological activity of msER$\alpha$, the cDNA was ligated to a mammalian expression vector and transfected into a gonadotrope-derived cell line, L$\beta$T2, with a reporter plasmid including estrogen responsive element. Expression of the reporter protein, luciferase, was E2 and msER$\alpha$-dependent. The masu salmon ER$\alpha$ is structurally conserved among teleost species and functions as a transcriptional activator in the pituitary cells.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.20
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• pp.8789-8791
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• 2014

Estrogen receptor alpha ($ER{\alpha}$) is one of the major sub-types of estrogen receptors. $ER{\alpha}$ plays an important role in cellular proliferation and differentiation, chiefly in mammary tissues. In the present study we aimed to quantify of $ER{\alpha}$ mRNA and protein expression in breast tissues from the Iranian population using a real-time PCR assay. Twenty nine breast tissues including 19 adenocarcinomas and 10 normal controls were recruited from the Iranian population. mRNA extraction and cDNA synthesis were performed from these tissues using commercial kits. $ER{\alpha}$ mRNA and protein expression was quantified using real-time PCR and immunohistochemistry respectively. The results showed high expression of $ER{\alpha}$ mRNA (68%) and protein (53%) in the majority of breast cancer tissues compared to normal breast tissues (p= 0.035). Also, high $ER{\alpha}$ mRNA was associated with tumour size of breast carcinomas. In this study, we first reported the expression of $ER{\alpha}$ in Iranian patients with breast cancers and demonstrated prevalence of the expression to be similar to breast cancers noted in other populations.

• Molecules and Cells
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• v.42 no.11
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• pp.783-793
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• 2019

When endoplasmic reticulum (ER) functions are perturbed, the ER induces several signaling pathways called unfolded protein response to reestablish ER homeostasis through three ER transmembrane proteins: inositol-requiring enzyme 1 (IRE1), PKR-like ER kinase (PERK), and activating transcription factor 6 (ATF6). Although it is important to measure the activity of ATF6 that can indicate the status of the ER, no specific cell-based reporter assay is currently available. Here, we report a new cell-based method for monitoring ER stress based on the cleavage of $ATF6{\alpha}$ by sequential actions of proteases at the Golgi apparatus during ER stress. A new expressing vector was constructed by using fusion gene of GAL4 DNA binding domain (GAL4DBD) and activation domain derived from herpes simplex virus VP16 protein (VP16AD) followed by a human $ATF6{\alpha}$ N-terminal deletion variant. During ER stress, the GAL4DBD-VP16AD(GV)-$hATF6{\alpha}$ deletion variant was cleaved to liberate active transcription activator encompassing GV-$hATF6{\alpha}$ fragment which could translocate into the nucleus. The translocated GV-$hATF6{\alpha}$ fragment strongly induced the expression of firefly luciferase in HeLa Luciferase Reporter cell line containing a stably integrated 5X GAL4 site-luciferase gene. The established double stable reporter cell line HLR-GV-$hATF6{\alpha}$(333) represents an innovative tool to investigate regulated intramembrane proteolysis of $ATF6{\alpha}$. It can substitute active pATF6(N) binding motif-based reporter cell lines.

• Biomolecules & Therapeutics
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• v.13 no.4
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• pp.227-231
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• 2005

The estrogen receptor (ER) is activated and degraded by estrogen. We have examined ER downregulation and activation under hypoxia mimetic conditions. Cobalt chloride induced ER downregulation at 24 h of treatment. This degradation involved hypoxia-inducible factor-1$\alpha$ (HIF-1$\alpha$) as examined by using a constitutively active form of HIF-1$\alpha$, HIF-1$\alpha$/VP16, constructed by replacing the transactivation domain of HIF-1$\alpha$ with that of VP16. Western blot analysis revealed that E2-induced ER downregulation was observed within ${\~}6h$, whereas HIF-1$\alpha$/VP16-induced ER degradation was observed within 12${\~}$20h. HIF-1$\alpha$/VP16 activated the transcription of estrogen-responsive reporter gene in the absence of estrogen. These results suggest that ER downregulation and activation under hypoxia maybe mediated in part by a HIP-1$\alpha$ expression.