| 1. |
- Alvarez-Baron, Claudia P, et al.
(författare)
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The two-pore domain potassium channel KCNK5 : induction by estrogen receptor alpha and role in proliferation of breast cancer cells.
- 2011
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Ingår i: Molecular Endocrinology. - : The Endocrine Society. - 0888-8809 .- 1944-9917. ; 25:8, s. 1326-36
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Tidskriftsartikel (refereegranskat)abstract
- The growth of many human breast tumors requires the proliferative effect of estrogen acting via the estrogen receptor α (ERα). ERα signaling is therefore a clinically important target for breast cancer prevention and therapeutics. Although extensively studied, the mechanism by which ERα promotes proliferation remains to be fully established. We observed an up-regulation of transcript encoding the pH-sensitive two-pore domain potassium channel KCNK5 in a screen for genes stimulated by 17β-estradiol (E2) in the ERα(+) breast cancer cell lines MCF-7 and T47D. KCNK5 mRNA increased starting 1 h after the onset of E2 treatment, and protein levels followed after 12 h. Estrogen-responsive elements are found in the enhancer region of KCNK5, and chromatin immunoprecipitation assays revealed binding of ERα to the KCNK5 enhancer in E2-treated MCF-7 cells. Cells treated with E2 also showed increases in the amplitude of pH-sensitive potassium currents, as assessed by whole-cell recordings. These currents are blocked by clofilium. Although confocal microscopy suggested that most of the channels are located in intracellular compartments, the increase in macroscopic currents suggests that E2 treatment increases the number of active channels at the cell surface. Application of small interfering RNA specific for KCNK5 decreased pH-sensitive potassium currents and also reduced the estrogen-induced proliferation of T47D cells. We conclude that E2 induces the expression of KCNK5 via ERα(+) in breast cancer cells, and this channel plays a role in regulating proliferation in these cell lines. KCNK5 may therefore represent a useful target for treatment, for example, of tamoxifen-resistant breast cancer.
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| 2. |
- Andersson, Sandra, et al.
(författare)
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Insufficient antibody validation challenges oestrogen receptor beta research
- 2017
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Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- The discovery of oestrogen receptor beta (ER beta/ESR2) was a landmark discovery. Its reported expression and homology with breast cancer pharmacological target ER alpha (ESR1) raised hopes for improved endocrine therapies. After 20 years of intense research, this has not materialized. We here perform a rigorous validation of 13 anti-ER beta antibodies, using well-characterized controls and a panel of validation methods. We conclude that only one antibody, the rarely used monoclonal PPZ0506, specifically targets ER beta in immunohistochemistry. Applying this antibody for protein expression profiling in 44 normal and 21 malignant human tissues, we detect ER beta protein in testis, ovary, lymphoid cells, granulosa cell tumours, and a subset of malignant melanoma and thyroid cancers. We do not find evidence of expression in normal or cancerous human breast. This expression pattern aligns well with RNA-seq data, but contradicts a multitude of studies. Our study highlights how inadequately validated antibodies can lead an exciting field astray.
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| 3. |
- Dahlman-Wright, Karin, et al.
(författare)
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Interplay between AP-1 and estrogen receptor α in regulating gene expression and proliferation networks in breast cancer cells
- 2012
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Ingår i: Carcinogenesis. - : Oxford University Press (OUP). - 0143-3334 .- 1460-2180. ; 33:9, s. 1684-91
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Tidskriftsartikel (refereegranskat)abstract
- Estrogen receptor α (ERα) is a ligand-dependent transcription factor that plays an important role in breast cancer. Estrogen-dependent gene regulation by ERα can be mediated by interaction with other DNA-binding proteins, such as activator protein-1 (AP-1). The nature of such interactions in mediating the estrogen response in breast cancer cells remains unclear. Here we show that knockdown of c-Fos, a component of the transcription factor AP-1, attenuates the expression of 37% of all estrogen-regulated genes, suggesting that c-Fos is a fundamental factor for ERα-mediated transcription. Additionally, knockdown of c-Fos affected the expression of a number of genes that were not regulated by estrogen. Pathway analysis reveals that silencing of c-Fos downregulates an E2F1-dependent proproliferative gene network. Thus, modulation of the E2F1 pathway by c-Fos represents a novel mechanism by which c-Fos enhances breast cancer cell proliferation. Furthermore, we show that c-Fos and ERα can cooperate in regulating E2F1 gene expression by binding to regulatory elements in the E2F1 promoter. To start to dissect the molecular details of the cross talk between AP-1 and estrogen signaling, we identify a novel ERα/AP-1 target, PKIB (cAMP-dependent protein kinase inhibitor-β), which is overexpressed in ERα-positive breast cancer tissues. Knockdown of PKIB results in robust growth suppression of breast cancer cells. Collectively, our findings support c-Fos as a critical factor that governs estrogen-dependent gene expression and breast cancer proliferation programs.
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| 4. |
- Dey, Prasenjit, et al.
(författare)
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Estrogen receptors β1 and β2 have opposing roles in regulating proliferation and bone metastasis genes in the prostate cancer cell line PC3
- 2012
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Ingår i: Molecular Endocrinology. - : The Endocrine Society. - 0888-8809 .- 1944-9917. ; 26:12, s. 1991-2003
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Tidskriftsartikel (refereegranskat)abstract
- The estrogen receptor (ER)β1 is successively lost during cancer progression, whereas its splice variant, ERβ2, is expressed in advanced prostate cancer. The latter form of cancer often metastasizes to bone, and we wanted to investigate whether the loss of ERβ1 and/or the expression of ERβ2 affect such signaling pathways in prostate cancer. Using PC3 and 22Rv1 prostate cancer cell lines that stably express ERβ1 or ERβ2, we found that the ERβ variants differentially regulate genes known to affect tumor behavior. We found that ERβ1 repressed the expression of the bone metastasis regulator Runx2 in PC3 cells. By contrast, RUNX2 expression was up-regulated at the mRNA level by ERβ2 in PC3 cells, whereas Slug was up-regulated by ERβ2 in both PC3 and 22Rv1 cells. In addition, the expression of Twist1, a factor whose expression strongly correlates with high Gleason grade prostate carcinoma, was increased by ERβ2. In agreement with the increased Twist1 expression, we found increased expression of Dickkopf homolog 1; Dickkopf homolog 1 is a factor that has been shown to increase the RANK ligand/osteoprotegerin ratio and enhance osteoclastogenesis, indicating that the expression of ERβ2 can cause osteolytic cancer. Furthermore, we found that only ERβ1 inhibited proliferation, whereas ERβ2 increased proliferation. The expression of the proliferation markers Cyclin E, c-Myc, and p45(Skp2) was differentially affected by ERβ1 and ERβ2 expression. In addition, nuclear β-catenin protein and its mRNA levels were reduced by ERβ1 expression. In conclusion, we found that ERβ1 inhibited proliferation and factors known to be involved in bone metastasis, whereas ERβ2 increased proliferation and up-regulated factors involved in bone metastasis. Thus, in prostate cancer cells, ERβ2 has oncogenic abilities that are in strong contrast to the tumor-suppressing effects of ERβ1.
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| 5. |
- Edvardsson, Karin, et al.
(författare)
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Estrogen receptor β induces antiinflammatory and antitumorigenic networks in colon cancer cells.
- 2011
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Ingår i: Molecular Endocrinology. - : The Endocrine Society. - 0888-8809 .- 1944-9917. ; 25:6, s. 969-79
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Tidskriftsartikel (refereegranskat)abstract
- Several studies suggest estrogen to be protective against the development of colon cancer. Estrogen receptor β (ERβ) is the predominant estrogen receptor expressed in colorectal epithelium and is the main candidate to mediate the protective effects. We have previously shown that expression of ERβ reduces growth of colorectal cancer in xenografts. Little is known of the actions of ERβ and its effect on gene transcription in colon cancers. To dissect the processes that ERβ mediates and to investigate cell-specific mechanisms, we reexpressed ERβ in three colorectal cancer cell lines (SW480, HT29, and HCT-116) and conducted genome-wide expression studies in combination with gene-pathway analyses and cross-correlation to ERβ-chromatin-binding sites. Although induced gene regulation was cell specific, overrepresentation analysis of functional classes indicated that the same biological themes, including apoptosis, cell differentiation, and regulation of the cell cycle, were affected in all three cell lines. Novel findings include a strong ERβ-mediated down-regulation of IL-6 and downstream networks with significant implications for inflammatory mechanisms involved in colon carcinogenesis. We also discovered cross talk between the suggested nuclear receptor coregulator PROX1 and ERβ, demonstrating that ERβ both regulates and shares target genes with PROX1. The influence of ERβ on apoptosis was further explored using functional studies, which suggested an increased DNA-repair capacity. We conclude that reexpression of ERβ induces transcriptome changes that, through several parallel pathways, converge into antitumorigenic capabilities in all three cell lines. We propose that enhancing ERβ action has potential as a novel therapeutic approach for prevention and/or treatment of colon cancer.
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| 6. |
- Ehrlund, Anna, et al.
(författare)
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Knockdown of SF-1 and RNF31 affects components of steroidogenesis, TGFβ, and Wnt/β-catenin signaling in adrenocortical carcinoma cells.
- 2012
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 7:3, s. e32080-
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Tidskriftsartikel (refereegranskat)abstract
- The orphan nuclear receptor Steroidogenic Factor-1 (SF-1, NR5A1) is a critical regulator of development and homeostasis of the adrenal cortex and gonads. We recently showed that a complex containing E3 ubiquitin ligase RNF31 and the known SF-1 corepressor DAX-1 (NR0B1) interacts with SF-1 on target promoters and represses transcription of steroidogenic acute regulatory protein (StAR) and aromatase (CYP19) genes. To further evaluate the role of SF-1 in the adrenal cortex and the involvement of RNF31 in SF-1-dependent pathways, we performed genome-wide gene-expression analysis of adrenocortical NCI-H295R cells where SF-1 or RNF31 had been knocked down using RNA interference. We find RNF31 to be deeply connected to cholesterol metabolism and steroid hormone synthesis, strengthening its role as an SF-1 coregulator. We also find intriguing evidence of negative crosstalk between SF-1 and both transforming growth factor (TGF) β and Wnt/β-catenin signaling. This crosstalk could be of importance for adrenogonadal development, maintenance of adrenocortical progenitor cells and the development of adrenocortical carcinoma. Finally, the SF-1 gene profile can be used to distinguish malignant from benign adrenocortical tumors, a finding that implicates SF-1 in the development of malignant adrenocortical carcinoma.
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| 7. |
- Howells, Mark I., et al.
(författare)
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Calabashes for kilowatt-hours : Rural energy and market failure
- 2010
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Ingår i: Energy Policy. - : Elsevier. - 0301-4215 .- 1873-6777. ; 38:6, s. 2729-2738
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes how management and information failures can retard transitions from the traditional use of biomass fuel by low income rural consumers and micro-producers. In general, societies move away from traditional biomass use as economic development takes place. If one accepts the doctrine of revealed preference (built on the initial work of Samuelson, 1938), then these trends imply that such transitions provide net gains in utility. This paper shows how various "failures" entrench existing fuel use patterns-hindering the transition to new fuel use patterns. In order to qualitatively discuss how these transitions may take place, an indicative neo-classical description of consumer and producer behavior is used. Three types fuel-transition "driver" are identified. The effect of information and management failures on these drivers, and thus the energy transition, is discussed. Reference is made to a specific case study in which a partial transition from biomass occurred in response to an intervention to address an environmental management failure (the deforesting of a carbon sink.) It is concluded that interventions to encourage transitions to cleaner sustainable fuel use may need to recognize and address management and information failures in a systematic manner.
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| 8. |
- Jonsson, Philip, et al.
(författare)
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Single-Molecule Sequencing Reveals Estrogen-Regulated Clinically Relevant lncRNAs in Breast Cancer
- 2015
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Ingår i: Molecular Endocrinology. - : The Endocrine Society. - 0888-8809 .- 1944-9917. ; 29:11
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Tidskriftsartikel (refereegranskat)abstract
- Estrogen receptor (ER)α-positive tumors are commonly treated with ERα antagonists or inhibitors of estrogen synthesis, but most tumors develop resistance, and we need to better understand the pathways that underlie the proliferative and tumorigenic role of this estrogen-activated transcription factor. We here present the first single-molecule sequencing of the estradiol-induced ERα transcriptome in the luminal A-type human breast cancer cell lines MCF7 and T47D. Sequencing libraries were prepared from the polyadenylated RNA fraction after 8 hours of estrogen or vehicle treatment. Single-molecule sequencing was carried out in biological and technical replicates and differentially expressed genes were defined and analyzed for enriched processes. Correlation analysis with clinical expression and survival were performed, and follow-up experiments carried out using time series, chromatin immunoprecipitation and quantitative real-time PCR. We uncovered that ERα in addition to regulating approximately 2000 protein-coding genes, also regulated up to 1000 long noncoding RNAs (lncRNAs). Most of these were up-regulated, and 178 lncRNAs were regulated in both cell lines. We demonstrate that Long Intergenic Non-protein Coding RNA 1016 (LINC01016) and LINC00160 are direct transcriptional targets of ERα, correlate with ERα expression in clinical samples, and show prognostic significance in relation to breast cancer survival. We show that silencing of LINC00160 results in reduced proliferation, demonstrating that lncRNA expression have functional consequences. Our findings suggest that ERα regulation of lncRNAs is clinically relevant and that their functions and potential use as biomarkers for endocrine response are important to explore.
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| 9. |
- Jonsson, Philip, et al.
(författare)
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Support of a bi-faceted role of estrogen receptor β (ERβ) in ERα-positive breast cancer cells.
- 2014
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Ingår i: Endocrine-Related Cancer. - 1351-0088 .- 1479-6821. ; 21:2, s. 143-160
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Tidskriftsartikel (refereegranskat)abstract
- The expression of estrogen receptor α (ERα) in breast cancer identifies patients most likely to respond to endocrine treatment. The second ER, ERβ, is also expressed in breast tumors, but its function and therapeutic potential need further study. Although in vitro studies have established that ERβ opposes transcriptional and proliferative functions of ERα, several clinical studies report its correlation with proliferative markers and poorer prognosis. The data demonstrate that ERβ opposes ERα are primarily based on transient expression of ERβ. Here, we explored the functions of constitutively expressed ERβ in ERα-positive breast cancer lines MCF7 and T47D. We found that ERβ, under these conditions heterodimerized with ERα in the presence and absence of 17β-estradiol, and induced genome-wide transcriptional changes. Widespread anti-ERα signaling was, however, not observed and ERβ was not antiproliferative. Tamoxifen antagonized proliferation and ER-mediated gene regulation both in the presence and absence of ERβ. In conclusion, ERβ's role in cells adapted to its expression appears to differ from its role in cells with transient expression. Our study is important because it provides a deeper understanding of ERβ's role in breast tumors that coexpress both receptors and supports an emerging bi-faceted role of ERβ.
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| 10. |
- Katchy, Anne, et al.
(författare)
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Coexposure to phytoestrogens and bisphenol a mimics estrogenic effects in an additive manner
- 2014
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Ingår i: Toxicological Sciences. - : Oxford University Press (OUP). - 1096-6080 .- 1096-0929. ; 138:1, s. 21-35
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Tidskriftsartikel (refereegranskat)abstract
- Endocrine-disrupting chemicals (EDC) are abundant in our environment. A number of EDCs, including bisphenol A (BPA) can bind to the estrogen receptors (ER), ERα and ERβ, and may contribute to estrogen-linked diseases such as breast cancer. Early exposure is of particular concern; many EDCs cross the placenta and infants have measurable levels of, eg, BPA. In addition, infants are frequently fed soy-based formula (SF) that contains phytoestrogens. Effects of combined exposure to xeno- and phytoestrogens are poorly studied. Here, we extensively compared to what extent BPA, genistein, and an extract of infant SF mimic estrogen-induced gene transcription and cell proliferation. We investigated ligand-specific effects on ER activation in HeLa-ERα and ERβ reporter cells; on proliferation, genome-wide gene regulation and non-ER-mediated effects in MCF7 breast cancer cells; and how coexposure influenced these effects. The biological relevance was explored using enrichment analyses of differentially regulated genes and clustering with clinical breast cancer profiles. We demonstrate that coexposure to BPA and genistein, or SF, results in increased functional and transcriptional estrogenic effects. Using statistical modeling, we determine that BPA and phytoestrogens act in an additive manner. The proliferative and transcriptional effects of the tested compounds mimic those of 17β-estradiol, and are abolished by cotreatment with an ER antagonist. Gene expression profiles induced by each compound clustered with poor prognosis breast cancer, indicating that exposure may adversely affect breast cancer prognosis. This study accentuates that coexposure to BPA and soy-based phytoestrogens results in additive estrogenic effects, and may contribute to estrogen-linked diseases, including breast cancer.
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