scholarly journals Estrogen stimulates SREBP2 expression in hepatic cell lines via an estrogen response element in the SREBP2 promoter

2019 ◽  
Vol 24 (1) ◽  
Author(s):  
Ye Meng ◽  
Lu Zong
Keyword(s):  
Chromatin Immunoprecipitation ◽  
Hepg2 Cells ◽  
Gene Promoter ◽  
Hepatic Cell ◽  
Luciferase Reporter ◽  
Estrogen Response Element ◽  
Reporter Assay ◽  
Lipid Disorder ◽  
Estrogen Response ◽  
Hepatic Cell Lines

Abstract Objective Hypoestrogenism in women is strongly associated with menopause and it can lead to lipid disorder, which predisposes people to premature cardiovascular disease. However, the mechanism of lipid disorder remains unclear. Sterol regulatory element-binding protein 2 (SREBP2) is the key transcription factor regulating cholesterol metabolism. We hypothesize that estrogen regulates SREBP2 transcription through an estrogen response element (ERE) in the SREBP2 promoter region. Methods Human hepatoblastoma cells (HepG2) were treated with dose-dependent concentrations of estradiol (E2) for 24 h. Then, SREBP2 expression was determined via real-time PCR and immunofluorescence. The expressions of the SREBP2 downstream target genes HMGCR and LDLR were determined via real-time PCR. Lipid secretion in the culture media of HepG2 cells was measured using ELISA. Through bioinformatics analysis, we identified high-scoring ERE-like sequences in the SREBP2 gene promoter. Chromatin immunoprecipitation analysis was used to confirm the ERE. DNA fragments of the putative or mutated ERE-like sequence were synthesized and ligated into pGL3-basic plasmid to construct the SREBP2 promoter luciferase reporter systems. SREBP2-Luciferase (SREBP2-Luc), SREBP2-Mutation (SREBP2-Mut) and the blank control were transfected into hepatic cell lines. Luciferase activities were measured using the dual-luciferase reporter assay system. Chromatin immunoprecipitation analysis and the luciferase reporter assay were repeated in human hepatoma cells (HuH-7). Results We found that E2 dose-dependently increased the expression of SREBP2 in HepG2 cells and that the increased levels were blocked when treated with an estrogen receptor-alpha antagonist. Additionally, E2 increased both HMGCR and LDLR expression and lipid secretion in HepG2 cells. Notably, we identified a functional ERE in the SREBP2 gene promoter, to which E2 could specifically bind and induce transcription. Conclusions An ERE was identified in the SREBP2 gene promoter. It mediates the regulation of SREBP2 expression by estrogen in hepatocytes. This study provides a mechanism to link cardiovascular disease with estrogen.

scholarly journals The Conundrum of Estrogen Receptor Oscillatory Activity in the Search for an Appropriate Hormone Replacement Therapy

Endocrinology ◽  
2011 ◽  
Vol 152 (6) ◽  
pp. 2256-2265 ◽  
Author(s):  
Sara Della Torre ◽  
Andrea Biserni ◽  
Gianpaolo Rando ◽  
Giuseppina Monteleone ◽  
Paolo Ciana ◽  
...  
Keyword(s):  
Estrogen Receptor ◽  
Transcriptional Activity ◽  
Hormone Replacement ◽  
Oscillatory Activity ◽  
Luciferase Reporter ◽  
Specific Gene ◽  
Estrogen Response Element ◽  
Response Element ◽  
Tissue Specific ◽  
Estrogen Response

By the use of in vivo imaging, we investigated the dynamics of estrogen receptor (ER) activity in intact, ovariectomized, and hormone-replaced estrogen response element-luciferase reporter mice. The study revealed the existence of a long-paced, noncircadian oscillation of ER transcriptional activity. Among the ER-expressing organs, this oscillation was asynchronous and its amplitude and period were tissue dependent. Ovariectomy affected the amplitude but did not suppress ER oscillations, suggesting the presence of tissue endogenous oscillators. Long-term administration of raloxifene, bazedoxifene, combined estrogens alone or with basedoxifene to ovariectomized estrogen response element-luciferase mice showed that each treatment induced a distinct spatiotemporal profile of ER activity, demonstrating that the phasing of ER activity among tissues may be regulated by the chemical nature and the concentration of circulating estrogen. This points to the possibility of a hierarchical organization of the tissue-specific pacemakers. Conceivably, the rhythm of ER transcriptional activity translates locally into the activation of specific gene networks enabling ER to significantly change its physiological activity according to circulating estrogens. In reproductive and nonreproductive organs this hierarchical regulation may provide ER with the signaling plasticity necessary to drive the complex metabolic changes occurring at each female reproductive status. We propose that the tissue-specific oscillatory activity here described is an important component of ER signaling necessary for the full hormone action including the beneficial effects reported for nonreproductive organs. Thus, this mechanism needs to be taken in due consideration to develop novel, more efficacious, and safer hormone replacement therapies.

scholarly journals MiR-196b-5p regulates the proliferation of drug-resistant hepatocellular carcinoma cell lines by activating NFκB/ABCB1 signaling pathway

2020 ◽  
Vol 19 (1) ◽  
pp. 39-44
Author(s):  
Bangming Pu ◽  
Yong Cao ◽  
Yan Li ◽  
Li Tang ◽  
Jiyi Xia ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Cycle ◽  
Cell Proliferation ◽  
Signaling Pathway ◽  
Cell Lines ◽  
Hepg2 Cells ◽  
Luciferase Reporter Assay ◽  
Luciferase Reporter ◽  
Drug Resistant ◽  
Reporter Assay

Purpose: To explore the molecular function of miR-196b-5p in hepatocellular carcinoma (HCC).Methods: MiR-196b-5p expression levels in HCC tissue samples were assessed by qRT-PCR. MiR-196b-5p was knocked-down or over-expressed in HepG2 cells by transfecting the cells with plasmids expressing either a miR-196b-5p inhibitor or mimic, respectively, while cell proliferation was  assessed by MTT assay. The interaction of miR-196b-5p with target molecules was confirmed using luciferase reporter assay. Cell cycle was investigated by flow cytometry, while NFκBIA expression was assessed by western blotting.Results: MiR-196b-5p was over-expressed in HCC, and miR-196b-5p expression levels in patients with HCC were related to tumor grade. MiR-196b-5p over-expression promoted cell proliferation and colony formation and suppressed cell cycle arrest and apoptosis. The results of luciferase reporter assay showed that miR-196b-5p reduced NFκBIA expression in HepG2 cells by binding to a response element in the 3′ UTR of NFκBIA. Further investigation showed that NFκBIA interacts with NFκB1 and reduces the concentration of NFκB1 in HepG2 cells. The promoter of ATP-binding cassette sub-family B member 1 (ABCB1) was also targeted and bound by NFκB1, which altered the expression of ABCB1 in HepG2 cells.Conclusion: MiR-196b-5p regulates cell proliferation in drug-resistant HCC cell lines via activation of the NFκB/ABCB1 signaling pathway. Keywords: Hepatocellular carcinoma, miR-196b-5p, NFκBIA, NFκB1, ABCB1

scholarly journals RelB/NF-κB2 Regulates Corticotropin-Releasing Hormone in the Human Placenta

2012 ◽  
Vol 26 (8) ◽  
pp. 1356-1369 ◽  
Author(s):  
Bingbing Wang ◽  
Nataliya Parobchak ◽  
Todd Rosen
Keyword(s):  
Human Placenta ◽  
Chromatin Immunoprecipitation ◽  
Transcriptional Activity ◽  
Nuclear Translocation ◽  
Gene Promoter ◽  
Significant Inhibition ◽  
Luciferase Reporter ◽  
Nuclear Staining ◽  
Heterologous Promoter ◽  
P100 Processing

Placental CRH may be part of a clock that governs the length of human gestation. The mechanism underlying differential regulation of CRH in the human placenta is poorly understood. We report here that constitutively activated RelB/nuclear factor-κB2 (NF-κB)-2 (p100/p52) acts as an endogenous stimulatory signal to regulate CRH by binding to an NF-κB enhancer of CRH gene promoter in the human placenta. Nuclear staining of NF-κB2 and RelB in villous syncytiotrophoblasts and cytotrophoblasts was coupled with cytoplasmic CRH in syncytial knots of cytotrophoblasts. Chromatin immunoprecipitation identified that CRH gene associated with both RelB and NF-κB2 (p52). Dexamethasone increased synthesis and nuclear translocation of RelB and NF-κB2 (p52) and their association with the CRH gene. In contrast, progesterone, a down-regulator of placental CRH, repressed NF-κB2 (p100) processing, nuclear translocation of RelB and NF-κB2 (p52), and their association with the CRH gene. Luciferase reporter assay determined that the NF-κB enhancer of CRH was sufficient to regulate transcriptional activity of a heterologous promoter in primary cytotrophoblasts. RNA interference-mediated repression of RelB or NF-κB2 resulted in significant inhibition of CRH at both transcriptional and translational levels and prevented the dexamethasone-mediated up-regulation of CRH transcription and translation. These results suggest that the noncanonical NF-κB pathway regulates CRH production in the human placenta and is responsible for the positive regulation of CRH by glucocorticoids.

Polymorphism of estrogen response element in TFF1 gene promoter is associated with an increased susceptibility to gastric cancer

Gene ◽  
2012 ◽  
Vol 492 (1) ◽  
pp. 100-103 ◽  
Author(s):  
Mehdi Moghanibashi ◽  
Parisa Mohamadynejad ◽  
Maryam Rasekhi ◽  
Abbas Ghaderi ◽  
Mohammad Mohammadianpanah
Keyword(s):  
Gastric Cancer ◽  
Gene Promoter ◽  
Estrogen Response Element ◽  
Response Element ◽  
Estrogen Response ◽  
Increased Susceptibility

Stimulation of peroxisomal palmitoyl-CoA oxidase activity by ciprofibrate in hepatic cell lines: Comparative studies in Fao, MH1C1 and HepG2 cells

1993 ◽  
Vol 77 (1) ◽  
pp. 37-41 ◽  
Author(s):  
Cécile Brocard ◽  
Malika Es-Souni ◽  
Leyla C Ramirez ◽  
Norbert Latruffe ◽  
Paulette Bournot
Keyword(s):  
Cell Lines ◽  
Comparative Studies ◽  
Hepg2 Cells ◽  
Oxidase Activity ◽  
Hepatic Cell ◽  
Hepatic Cell Lines ◽  
Stimulation Of

Cloning the uteroglobin gene promoter from the relic volcano rabbit (Romerolagus diazi) reveals an ancient estrogen-response element

2012 ◽  
Vol 79 (5) ◽  
pp. 337-345 ◽  
Author(s):  
Adriana Acosta-MontesdeOca ◽  
Teresa Zariñán ◽  
Héctor Macías ◽  
Marco A. Pérez-Solís ◽  
Alfredo Ulloa-Aguirre ◽  
...  
Keyword(s):  
Gene Promoter ◽  
Estrogen Response Element ◽  
Response Element ◽  
Estrogen Response

scholarly journals Human Prolactin Gene Promoter Regulation by Estrogen: Convergence with Tumor Necrosis Factor-α Signaling

Endocrinology ◽  
2007 ◽  
Vol 149 (2) ◽  
pp. 687-694 ◽  
Author(s):  
A. D. Adamson ◽  
S. Friedrichsen ◽  
S. Semprini ◽  
C. V. Harper ◽  
J. J. Mullins ◽  
...  
Keyword(s):  
Gene Promoter ◽  
Gh3 Cells ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Estrogen Response ◽  
Synergistic Activation ◽  
Prolactin Gene ◽  
Human Prolactin ◽  
Factor Α

Estrogens have been implicated in the regulation of prolactin gene expression in man, although previous studies have not defined the molecular mechanism whereby estradiol activates the human prolactin gene promoter (hPrl). We found that estradiol induced a reproducible 1.8-fold activation of the hPrl gene promoter, using pituitary GH3 cells stably transfected with a 5000-bp hPrl promoter fragment linked to luciferase reporter gene. This activation was blocked by treatment with estrogen receptor (ER) antagonists 4-hydroxytamoxifen and ICI-182,780. Promoter deletion and mutagenesis experiments identified a functional estrogen response element (ERE) sequence 1189 bp upstream of the transcription start site that was responsible for estrogen-mediated promoter activation. This site differed from the consensus ERE sequence by two base pairs, one in each half-site. This ERE was identified to be functional through binding ERα in EMSAs. Chromatin immunoprecipitation assays confirmed ERα binding to this sequence in vivo in the absence of ligand, with increased recruitment when cells were cultured in the presence of estradiol. When cells were treated with both estradiol and TNFα, we observed synergistic activation of the hPrl promoter, which was mediated by the −1189-bp ERE. Mutagenesis of this ERE abolished the promoter-activating effect not only of estradiol but also of TNFα. These data suggest a novel, promoter-specific signaling interaction between estrogen and TNFα signaling, which is likely to be important for prolactin regulation in vivo.

scholarly journals Estradiol induces type 8 17β-hydroxysteroid dehydrogenase expression: crosstalk between estrogen receptor α and C/EBPβ

2008 ◽  
Vol 200 (1) ◽  
pp. 85-92 ◽  
Author(s):  
Mirja Rotinen ◽  
Jon Celay ◽  
Marta M Alonso ◽  
Aranzazu Arrazola ◽  
Ignacio Encio ◽  
...  
Keyword(s):  
Estrogen Receptor ◽  
Chromatin Immunoprecipitation ◽  
Hepg2 Cells ◽  
Ectopic Expression ◽  
Estrogen Receptor Α ◽  
Proximal Promoter ◽  
Transcription Start ◽  
Estrogen Response ◽  
Human And Mouse ◽  
Mcf 7

Hydroxysteroid (17-beta) dehydrogenase (HSD17B) are the enzymes responsible for the reversible interconversion of 17-hydroxy and 17-keto steroids. The human and mouse type 8 17β-HSD (HSD17B8) selectively catalyze the conversion ofestradiol (E2) to estrone (E1). We previously described thatHSD17B8 is transcriptionally regulated by C/EBPβ, andthat C/EBPβ is bound to CCAAT boxes located at −5 and −46 of the transcription start site in basal conditions in HepG2 cells. Furthermore, ectopic expression of C/EBPβ transactivated the HSD17B8 promoter activity. Here, we show that HSD17B8 expression is up-regulated in response toE2 in the estrogen receptor α (ERα) positive MCF-7 cells. Results showed that this induction is mediated by ERα because i) E2 did not induce HSD17B8 expression in ERαnegative HepG2 cells, ii) ectopic expression of ERα restored E2-induced HSD17B8 expression, and iii) this induction wasblocked by the anti-ER ICI 182 780. Additional experiments showed that no estrogen response element was necessary for this regulation. However, the CCAAT boxes located at the HSD17B8 proximal promoter were required for E2-induced transcription. Furthermore, co-immunoprecipitation studies revealed tethering of ERαtoC/EBPβ inresponse to E2 in cells expressing ERα. Additionally, chromatin immunoprecipitation assays demonstrated that, in response to E2, ERα is recruited to the CCAAT boxes in which C/EBPβ is already bound. Taken together, our results reveal that ERα is involved in the transcriptional regulation ofHSD17B8gene in response to E2 through its interaction with C/EBPβ.

scholarly journals MKL1 and STAT3 activate the activity of the luciferase reporter plasmid containing the CAAP1 gene promoter

2019 ◽  
Vol 78 ◽  
pp. 01003
Author(s):  
Jun-Yan Li ◽  
Zhu Yu ◽  
Feng-Yun Wang
Keyword(s):  
Breast Cancer ◽  
Breast Cancer Cells ◽  
Gene Promoter ◽  
Luciferase Reporter ◽  
Reporter Assay ◽  
Reporter Plasmid ◽  
Transcription Activity ◽  
Luciferase Reporter Plasmid ◽  
The Relationship ◽  
Mcf 7

Breast cancer is the leading cause of cancer death in women worldwide. The etiology of the disease is not yet clear. We know that MKL1 and STAT3 play an important part in the development and progression of breast cancer. CAAP1 is a ubiquitous and highly conserved protein that is closely related to the apoptotic process of tumors. However, the definitive transcriptional mechanism of the CAAP1 gene is still unclear. In our study, we constructed a luciferase reporter plasmid for the human CAAP1 gene promoter. Then one or both of the two overexpression vectors of MKL-1 and STAT3 were co-transfected into MCF-7 cells with CAAP1 promoter plasmid, and we then tested activation of the CAAP1 promoter by luciferase reporter assay. The results show that compared with the transfected pcDNA3.1 group, MKL1 can evidently increase the transcription activity of the CAAP1 gene promoter, while the STAT3 group can slightly upregulate the transcription activity of the CAAP1 gene promoter. Our research will further reveal the relationship between CAAP1 and the occurrence and development of breast cancer cells, and provide a new idea and direction for the cures of breast cancer.

Sign in / Sign up

Export Citation Format

Share Document