scholarly journals KISS1 Is Down-Regulated by 17β-Estradiol in MDA-MB-231 Cells through a Nonclassical Mechanism and Loss of Ribonucleic Acid Polymerase II Binding at the Proximal Promoter

Endocrinology ◽  
2010 ◽  
Vol 151 (8) ◽  
pp. 3764-3772 ◽  
Author(s):  
Lukas Huijbregts ◽  
Nicolas de Roux
Keyword(s):  
Rna Polymerase Ii ◽  
Cell Line ◽  
Molecular Mechanisms ◽  
Active Form ◽  
Cancer Cell Line ◽  
Estrogen Receptor Α ◽  
Proximal Promoter ◽  
Gene Body ◽  
Down Regulation ◽  
17Β Estradiol

Kisspeptins are hypothalamic neuropeptides encoded by KISS1 and recently described as major regulators of GnRH release from hypothalamic neurons. Although 17β-estradiol (E2)-induced up-regulation of KISS1 expression has been documented in anteroventral periventricular nucleus neurons, E2 down-regulates KISS1 expression in arcuate nucleus neurons via the estrogen receptor α by unknown molecular mechanisms. Because KISS1 was initially described as a metastasis inhibitor, notably in breast tumors, we used the MDA-MB-231 breast cancer cell line, which expresses high levels of KISS1, to characterize the molecular mechanism underlying KISS1 regulation by E2. E2 rapidly down-regulated endogenous KISS1 in a stable ERα-expressing MDA-MB-231 cell line. Promoter analysis revealed that E2 down-regulation was determined by a short 93-bp sequence devoid of estrogen response element and Sp1 sites. E2 down-regulation persisted with an ERα that was unable to bind DNA and in the presence of histone deacetylase inhibitor. In the absence of E2, unliganded ERα and RNA polymerase II (RNAPII) were present on the proximal promoter. E2 stimulation induced recruitment of ERα and loss of RNAPII at the proximal promoter. Along the gene body, total RNAPII amounts were similar in E2-treated and untreated cells, whereas the active form was significantly less abundant in E2-treated cells. Thus, E2-induced down-regulation of KISS1 is mediated by a pathway combining RNAPII loss at the proximal promoter and modulation of active RNAPII along the gene body, which is a novel mechanism in the complex process of E2-induced repression of gene expression.

scholarly journals Analysis of a Preliminary microRNA Expression Signature in a Human Telangiectatic Osteogenic Sarcoma Cancer Cell Line

2021 ◽  
Vol 22 (3) ◽  
pp. 1163
Author(s):  
Gaia Palmini ◽  
Cecilia Romagnoli ◽  
Simone Donati ◽  
Roberto Zonefrati ◽  
Gianna Galli ◽  
...  
Keyword(s):  
Cell Line ◽  
Molecular Mechanisms ◽  
Osteogenic Sarcoma ◽  
Cancer Cell Line ◽  
Microscopic Features ◽  
In Vitro Establishment ◽  
Profile Characteristic ◽  
First Time

Telangiectatic osteosarcoma (TOS) is an aggressive variant of osteosarcoma (OS) with distinctive radiographic, gross, microscopic features, and prognostic implications. Despite several studies on OS, we are still far from understanding the molecular mechanisms of TOS. In recent years, many studies have demonstrated not only that microRNAs (miRNAs) are involved in OS tumorigenesis, development, and metastasis, but also that the presence in high-grade types of OS of cancer stem cells (CSCs) plays an important role in tumor progression. Despite these findings, nothing has been described previously about the expression of miRNAs and the presence of CSCs in human TOS. Therefore, we have isolated/characterized a putative CSC cell line from human TOS (TOS-CSCs) and evaluated the expression levels of several miRNAs in TOS-CSCs using real-time quantitative assays. We show, for the first time, the existence of CSCs in human TOS, highlighting the in vitro establishment of this unique stabilized cell line and an identification of a preliminary expression of the miRNA profile, characteristic of TOS-CSCs. These findings represent an important step in the study of the biology of one of the most aggressive variants of OS and the role of miRNAs in TOS-CSC behavior.

Depletion of MUC5B mucin in gastrointestinal cancer cells alters their tumorigenic properties: implication of the Wnt/β-catenin pathway

2017 ◽  
Vol 474 (22) ◽  
pp. 3733-3746 ◽  
Author(s):  
Fatima Lahdaoui ◽  
Mathieu Messager ◽  
Audrey Vincent ◽  
Flora Hec ◽  
Anne Gandon ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Cell Line ◽  
Cancer Cell ◽  
Gastrointestinal Cancer ◽  
Tumour Growth ◽  
Cancer Cell Line ◽  
Migration And Invasion ◽  
Down Regulation

Secreted mucins are large O-glycosylated proteins that participate in the protection/defence of underlying mucosae in normal adults. Alteration of their expression is a hallmark of numerous epithelial cancers and has often been correlated to bad prognosis of the tumour. The secreted mucin MUC5B is overexpressed in certain subtypes of gastric and intestinal cancers, but the consequences of this altered expression on the cancer cell behaviour are not known. To investigate the role of MUC5B in carcinogenesis, its expression was knocked-down in the human gastric cancer cell line KATO-III and in the colonic cancer cell line LS174T by using transient and stable approaches. Consequences of MUC5B knocking-down on cancer cells were studied with respect to in vitro proliferation, migration and invasion, and in vivo on tumour growth using a mouse subcutaneous xenograft model. Western blotting, luciferase assay and qRT–PCR were used to identify proteins and signalling pathways involved. In vitro MUC5B down-regulation leads to a decrease in proliferation, migration and invasion properties in both cell lines. Molecular mechanisms involved the alteration of β-catenin expression, localization and activity and decreased expression of several of its target genes. In vivo xenografts of MUC5B-deficient cells induced a decrease in tumour growth when compared with MUC5B-expressing Mock cells. Altogether, the present study shows that down-regulation of MUC5B profoundly alters proliferation, migration and invasion of human gastrointestinal cancer cells and that these alterations may be, in part, mediated by the Wnt/β-catenin pathway emphasizing the potential of MUC5B as an actor of gastrointestinal carcinogenesis.

scholarly journals Oxytocin Receptor Down-Regulation Is Not Necessary for Reducing Oxytocin-Induced Prostaglandin F2α Accumulation by Interferon-τ in a Bovine Endometrial Epithelial Cell Line

Endocrinology ◽  
2009 ◽  
Vol 150 (2) ◽  
pp. 897-905 ◽  
Author(s):  
Narayanan Krishnaswamy ◽  
Ghislain Danyod ◽  
Pierre Chapdelaine ◽  
Michel A. Fortier
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Cell Line ◽  
Molecular Mechanisms ◽  
Prostaglandin F2α ◽  
Epithelial Cell Line ◽  
Dependent Manner ◽  
Down Regulation ◽  
Endometrial Epithelial Cell ◽  
Endometrial Epithelial Cells

Interferon-τ (IFNτ) is the embryonic signal responsible for pregnancy recognition in ruminants. The primary action of IFNτ is believed to be mediated through inhibition of prostaglandin F2α (PGF2α) released from the endometrial epithelial cells in response to oxytocin (OT). Our working hypothesis was that the antiluteolytic effect of IFNτ also involved modulation of PG production downstream of OT receptor (OTR) and/or cyclooxygenase 2 (COX2). There is currently no OT-sensitive endometrial cell line to study the molecular mechanisms underlying our hypotheses. Therefore, we established an immortalized bovine endometrial epithelial cell line (bEEL) exhibiting OT response. These cells were cytokeratin positive, expressed steroid receptors, and exhibited preferential accumulation of PGF2α over PGE2. The bEEL cells were highly sensitive to OT, showing time- and concentration-dependent increase in COX2 transcript and protein and PGF2α accumulation. Interestingly, IFNτ (20 ng/ml) significantly reduced OT-induced PGF2α accumulation, but surprisingly, the effect was not mediated through down-regulation of either OTR or COX2. Rather, IFNτ up-regulated COX2 in a time- and concentration-dependent manner while decreasing OT-induced PG accumulation. This suggests that COX2 is not a primary target for the antiluteolytic effect of IFNτ. Because IFNτ reduced OT-stimulated PGF2α accumulation within 3 h, the mechanism likely involves a direct interference at the level of the OT signaling or transcription in addition to the down-regulation of OTR observed in vivo. In summary, bEEL cells offer a unique in vitro model for investigating the cellular and molecular mechanisms underlying OT and IFNτ response in relation with luteolysis and recognition of pregnancy in the bovine. Interferon-τ acts as a competitive partial agonist, stimulating basal but inhibiting oxytocin- and phorbol myristate acetate-stimulated prostaglandin F2α production in immortalized bovine endometrial epithelial cells.

scholarly journals 17β-Estradiol Stimulates Expression of Osteoprotegerin by a Mouse Stromal Cell Line, ST-2, via Estrogen Receptor-α*

Endocrinology ◽  
2001 ◽  
Vol 142 (6) ◽  
pp. 2205-2212 ◽  
Author(s):  
Mieko Saika ◽  
Daisuke Inoue ◽  
Shinsuke Kido ◽  
Toshio Matsumoto
Keyword(s):  
Estrogen Receptor ◽  
Cell Line ◽  
Stromal Cell ◽  
Estrogen Receptor Α ◽  
Stromal Cell Line ◽  
17Β Estradiol

scholarly journals Gαo potentiates estrogen receptor α activity via the ERK signaling pathway

2012 ◽  
Vol 214 (1) ◽  
pp. 45-54 ◽  
Author(s):  
Melyssa R Bratton ◽  
James W Antoon ◽  
Bich N Duong ◽  
Daniel E Frigo ◽  
Syreeta Tilghman ◽  
...  
Keyword(s):  
Estrogen Receptor ◽  
Mapk Pathway ◽  
Biological Effects ◽  
Cancer Cell Line ◽  
Estrogen Receptor Α ◽  
Signaling Cascades ◽  
Protein Subunit ◽  
Western Blots ◽  
Reporter Assays ◽  
17Β Estradiol

The estrogen receptor α (ERα) is a transcription factor that mediates the biological effects of 17β-estradiol (E2). ERα transcriptional activity is also regulated by cytoplasmic signaling cascades. Here, several Gα protein subunits were tested for their ability to regulate ERα activity. Reporter assays revealed that overexpression of a constitutively active Gαoprotein subunit potentiated ERα activity in the absence and presence of E2. Transient transfection of the human breast cancer cell line MCF-7 showed that Gαoaugments the transcription of several ERα-regulated genes. Western blots of HEK293T cells transfected with ER±Gαorevealed that Gαostimulated phosphorylation of ERK 1/2 and subsequently increased the phosphorylation of ERα on serine 118. In summary, our results show that Gαo, through activation of the MAPK pathway, plays a role in the regulation of ERα activity.

scholarly journals Down-regulation of miR-543 expression increases the sensitivity of colorectal cancer cells to 5-Fluorouracil through the PTEN/PI3K/AKT pathway

2019 ◽  
Vol 39 (3) ◽  
Author(s):  
Gang Liu ◽  
JianPing Zhou ◽  
Ming Dong
Keyword(s):  
Colorectal Cancer ◽  
Colon Cancer ◽  
Cancer Cells ◽  
Cell Line ◽  
Cancer Cell ◽  
Cancer Cell Line ◽  
Colon Cancer Cell Line ◽  
Colon Cancer Cell ◽  
Akt Pathway ◽  
Down Regulation

Abstract Resistance to chemotherapy is one of main obstacles in the treatment of colorectal cancer (CRC). However, the mechanisms are still unclear, and the treatment options are still limited. miR-543 has been indicated to act as an oncogene in some cancers, but its function in regulating chemoresistance has not been considered in CRC cells. This study investigated whether the down-regulation of miR-543 expression enhanced 5-fluorouracil (5-FU)-induced apoptosis in HCT8/FU colon cancer cells. In our study, qRT-PCR revealed that miR-543 expression was up-regulated in the HCT8/FU colon cancer cell line compared with that of HCT8 colon cancer cell line. An miR-543 inhibitor or mimic was transfected, followed by MTT assay to detect 5-FU sensitivity in HCT8 and HCT8/FU cell lines, which showed that IC50 of 5-FU was positively correlated with miR-543 expression. Further studies showed that miR-543 enhanced drug resistance by down-regulating the expression of phosphatase and tensin homolog (PTEN), which negatively regulates protein kinase B (AKT) activation. Additionally, an elevated expression of PTEN reversed the chemoresistance of miR-543-overexpressing HCT8 cells to 5-FU. These results indicate that miR-543 might be a target to increase the sensitivity of CRC cells to 5-FU through the PTEN/PI3K/AKT pathway.

scholarly journals 1,25(OH)2D3 Alleviates Aβ(25-35)-Induced Tau Hyperphosphorylation, Excessive Reactive Oxygen Species, and Apoptosis Through Interplay with Glial Cell Line-Derived Neurotrophic Factor Signaling in SH-SY5Y Cells

2020 ◽  
Vol 21 (12) ◽  
pp. 4215 ◽  
Author(s):  
Ching-I Lin ◽  
Yi-Chen Chang ◽  
Ning-Jo Kao ◽  
Wei-Ju Lee ◽  
Tzu-Wen Cross ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Vitamin D ◽  
Cell Line ◽  
Glial Cell ◽  
Neurotrophic Factor ◽  
Molecular Mechanisms ◽  
Active Form ◽  
Reactive Oxygen ◽  
Nuclear Hormone Receptor ◽  
Oxygen Species

Amyloid beta (Aβ) accumulation in the brain is one of the major pathological features of Alzheimer’s disease. The active form of vitamin D (1,25(OH)2D3), which acts via its nuclear hormone receptor, vitamin D receptor (VDR), has been implicated in the treatment of Aβ pathology, and is thus considered as a neuroprotective agent. However, its underlying molecular mechanisms of action are not yet fully understood. Here, we aim to investigate whether the molecular mechanisms of 1,25(OH)2D3 in ameliorating Aβ toxicity involve an interplay of glial cell line-derived neurotrophic factor (GDNF)-signaling in SH-SY5Y cells. Cells were treated with Aβ(25-35) as the source of toxicity, followed by the addition of 1,25(OH)2D3 with or without the GDNF inhibitor, heparinase III. The results show that 1,25(OH)2D3 modulated Aβ-induced reactive oxygen species, apoptosis, and tau protein hyperphosphorylation in SH-SY5Y cells. Additionally, 1,25(OH)2D3 restored the decreasing GDNF and the inhibited phosphorylation of the phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt)/glycogen synthase kinase-3β (GSK-3β) protein expressions. In the presence of heparinase III, these damaging effects evoked by Aβ were not abolished by 1,25(OH)2D3. It appears 1,25(OH)2D3 is beneficial for the alleviation of Aβ neurotoxicity, and it might elicit its neuroprotection against Aβ neurotoxicity through an interplay with GDNF-signaling.

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