scholarly journals SREBP1 drives KRT80-dependent cytoskeletal changes and invasive behavior in endocrine resistant ERα breast cancer

2018 ◽  
Author(s):  
Ylenia Perone ◽  
Aaron J. Farrugia ◽  
Alba Rodriguez Meira ◽  
Balázs Győrffy ◽  
Charlotte Ion ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Invasion ◽  
De Novo ◽  
Regulatory Element ◽  
Leading Edge ◽  
Clinical Endpoints ◽  
Breast Cancer Relapse ◽  
Element Binding Protein ◽  
Cytoskeletal Rearrangements

AbstractApproximately 30% of women diagnosed with ERα breast cancer relapse with metastatic disease following adjuvant treatment with endocrine therapies1,2. The connection between acquisition of drug resistance and invasive potential is poorly understood. In this study, we demonstrate that the type II keratin topological associating domain (TAD)3 undergoes epigenetic reprogramming in cells that develop resistance to aromatase inhibitors (AI), leading to keratin 80 (KRT80) upregulation. In agreement, an increased number of KRT80-positive cells are observed at relapse in vivo while KRT80 expression associates with poor outcome using several clinical endpoints. KRT80 expression is driven by de novo enhancer activation by sterol regulatory element-binding protein 14 (SREBP1). KRT80 upregulation directly promotes cytoskeletal rearrangements at the leading edge, increased focal adhesion maturation and cellular stiffening, which collectively promote cancer cell invasion. Shear-wave elasticity imaging of prospective patients shows that KRT80 levels correlate with stiffer tumors in vivo. Collectively, our data uncover an unpredicted and potentially targetable direct link between epigenetic and cytoskeletal reprogramming promoting cell invasion in response to chronic AI treatment.

Abstract 434: Insig-2a Links CREBH Signaling to Hepatic Lipogenesis and Systemic Hyperlipidemia

2013 ◽  
Vol 33 (suppl_1) ◽  
Author(s):  
Hai Wang ◽  
Qiaozhu Su
Keyword(s):  
De Novo ◽  
Regulatory Element ◽  
Hepatoma Cell ◽  
Gene Promoter ◽  
De Novo Lipogenesis ◽  
Signal Pathways ◽  
Hepatoma Cell Line ◽  
Protein Levels ◽  
Element Binding Protein

The sterol regulatory element binding proteins (SREBPs) are master transcription factors that regulate hepatic de novo lipogenesis. Perturbation of SREBPs functionality is closely related to the onset of hyperlipidemia. The current investigation sought to advance our understanding on the activation of SREBP-1c via the interplay between the cAMP responsive element binding protein H (CREBH) and the liver specific insulin-induced gene 2a isoform (Insig-2a). Genetic depletion of CREBH specifically down regulated expression of both Insign-2a mRNA and protein levels which resulted in the hyperactivation of SREBP-1c and the subsequent hypertriglyceridemia. Challenging wild type (WT) mice with a high fat diet (HFD) specifically stimulated expression of Insig-2a mRNA and protein in the WT mice. In contrast, HFD failed to enhance expressions of Insig-2a mRNA and protein in CREBH-null mice. No alterations were detected on the mRNA transcription of another Insig-2 isoform, Insig-2b, in the livers of WT mice and CREBH-null mice under both chow and HFD conditions. Decrease of Insig-2a caused activation of hepatic de novo lipogenesis, mainly via SREBP-1c activation, which contributed to the development of sever systemic hypertriglyceridemia and hepatic steatosis in CREBH-null mice. Consistent with the in vivo observation, forced expression of CREBH cDNA in a rat hepatoma cell line, McA cells, specifically increased expressions of both Insig-2a mRNA and protein which in turn inhibited activation of SCREBP-1c. Analyzing the gene promoter of Insig-2a, we identified a CREB binding site at the promoter of the Insig-2a and a ChIP assay further confirmed the physical association between CREBH and the Insig-2a promoter. These data identify Insig-2a as a target gene of CREBH. Modulation of Insig-2a expression by CREBH is essentially involved in regulating hepatic triglyceride metabolism. Given the role of CREBH in hepatic acute phage response signaling, this finding further reveals the cross-talk between inflammatory and insulin signal pathways in maintaining systemic lipid homeostasis and may provide rationale for pharmaceutical design to specifically target CREBH and insig-2a in the prevention and treatment of hypertriglyceridemia.

scholarly journals Integrin α3β1 Promotes Invasive and Metastatic Properties of Breast Cancer Cells through Induction of the Brn-2 Transcription Factor

Cancers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 480
Author(s):  
Rakshitha Pandulal Miskin ◽  
Janine S. A. Warren ◽  
Abibatou Ndoye ◽  
Lei Wu ◽  
John M. Lamar ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Transcription Factor ◽  
Cancer Cells ◽  
Cell Invasion ◽  
Breast Cancer Cells ◽  
Gene Promoter ◽  
Akt Inhibitor ◽  
Integrin Α3β1

In the current study, we demonstrate that integrin α3β1 promotes invasive and metastatic traits of triple-negative breast cancer (TNBC) cells through induction of the transcription factor, Brain-2 (Brn-2). We show that RNAi-mediated suppression of α3β1 in MDA-MB-231 cells caused reduced expression of Brn-2 mRNA and protein and reduced activity of the BRN2 gene promoter. In addition, RNAi-targeting of Brn-2 in MDA-MB-231 cells decreased invasion in vitro and lung colonization in vivo, and exogenous Brn-2 expression partially restored invasion to cells in which α3β1 was suppressed. α3β1 promoted phosphorylation of Akt in MDA-MB-231 cells, and treatment of these cells with a pharmacological Akt inhibitor (MK-2206) reduced both Brn-2 expression and cell invasion, indicating that α3β1-Akt signaling contributes to Brn-2 induction. Analysis of RNAseq data from patients with invasive breast carcinoma revealed that high BRN2 expression correlates with poor survival. Moreover, high BRN2 expression positively correlates with high ITGA3 expression in basal-like breast cancer, which is consistent with our experimental findings that α3β1 induces Brn-2 in TNBC cells. Together, our study demonstrates a pro-invasive/pro-metastatic role for Brn-2 in breast cancer cells and identifies a role for integrin α3β1 in regulating Brn-2 expression, thereby revealing a novel mechanism of integrin-dependent breast cancer cell invasion.

Regulation of fatty acid synthase expression in breast cancer by sterol regulatory element binding protein-1c

2003 ◽  
Vol 282 (2) ◽  
pp. 132-137 ◽  
Author(s):  
Y.u-A.n Yang ◽  
Patrice J. Morin ◽  
Wan Fang Han ◽  
Tinghua Chen ◽  
Daniel M. Bornman ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Fatty Acid ◽  
Fatty Acid Synthase ◽  
Binding Protein ◽  
Regulatory Element ◽  
Element Binding Protein ◽  
Sterol Regulatory Element

scholarly journals CRISPR/Cas9-mediated editing of Δ5 and Δ6 desaturases impairs Δ8-desaturation and docosahexaenoic acid synthesis in Atlantic salmon (Salmo salar L.)

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Alex K. Datsomor ◽  
Rolf E. Olsen ◽  
Nikola Zic ◽  
Angelico Madaro ◽  
Atle M. Bones ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Regulatory Element ◽  
Acid Synthesis ◽  
Fatty Acyl ◽  
Chain Polyunsaturated Fatty Acid ◽  
Pufa Diet ◽  
Element Binding Protein ◽  
Sterol Regulatory Element ◽  
High Degree

AbstractThe in vivo functions of Atlantic salmon fatty acyl desaturases (fads2), Δ6fads2-a, Δ6fads2-b, Δ6fads2-c and Δ5fads2 in long chain polyunsaturated fatty acid (LC-PUFA) synthesis in salmon and fish in general remains to be elucidated. Here, we investigate in vivo functions and in vivo functional redundancy of salmon fads2 using two CRISPR-mediated partial knockout salmon, Δ6abc/5Mt with mutations in Δ6fads2-a, Δ6fads2-b, Δ6fads2-c and Δ5fads2, and Δ6bcMt with mutations in Δ6fads2-b and Δ6fads2-c. F0 fish displaying high degree of gene editing (50–100%) were fed low LC-PUFA and high LC-PUFA diets, the former containing reduced levels of eicosapentaenoic (20:5n-3) and docosahexaenoic (22:6n-3) acids but higher content of linoleic (18:2n-6) and alpha-linolenic (18:3n-3) acids, and the latter containing high levels of 20:5n-3 and 22:6n-3 but reduced compositions of 18:2n-6 and 18:3n-3. The Δ6abc/5Mt showed reduced 22:6n-3 levels and accumulated Δ6-desaturation substrates (18:2n-6, 18:3n-3) and Δ5-desaturation substrate (20:4n-3), demonstrating impaired 22:6n-3 synthesis compared to wildtypes (WT). Δ6bcMt showed no effect on Δ6-desaturation compared to WT, suggesting Δ6 Fads2-a as having the predominant Δ6-desaturation activity in salmon, at least in the tissues analyzed. Both Δ6abc/5Mt and Δ6bcMt demonstrated significant accumulation of Δ8-desaturation substrates (20:2n-6, 20:3n-3) when fed low LC-PUFA diet. Additionally, Δ6abc/5Mt demonstrated significant upregulation of the lipogenic transcription regulator, sterol regulatory element binding protein-1 (srebp-1) in liver and pyloric caeca under reduced dietary LC-PUFA. Our data suggest a combined effect of endogenous LC-PUFA synthesis and dietary LC-PUFA levels on srebp-1 expression which ultimately affects LC-PUFA synthesis in salmon. Our data also suggest Δ8-desaturation activities for salmon Δ6 Fads2 enzymes.

scholarly journals A New Role for Sterol Regulatory Element Binding Protein 1 Transcription Factors in the Regulation of Muscle Mass and Muscle Cell Differentiation

2009 ◽  
Vol 30 (5) ◽  
pp. 1182-1198 ◽  
Author(s):  
Virginie Lecomte ◽  
Emmanuelle Meugnier ◽  
Vanessa Euthine ◽  
Christine Durand ◽  
Damien Freyssenet ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Muscle Mass ◽  
Target Genes ◽  
Binding Protein ◽  
Regulatory Element ◽  
Element Binding Protein ◽  
Sterol Regulatory Element ◽  
Myogenic Program

ABSTRACT The role of the transcription factors sterol regulatory element binding protein 1a (SREBP-1a) and SREBP-1c in the regulation of cholesterol and fatty acid metabolism has been well studied; however, little is known about their specific function in muscle. In the present study, analysis of recent microarray data from muscle cells overexpressing SREBP1 suggested that they may play a role in the regulation of myogenesis. We then demonstrated that SREBP-1a and -1c inhibit myoblast-to-myotube differentiation and also induce in vivo and in vitro muscle atrophy. Furthermore, we have identified the transcriptional repressors BHLHB2 and BHLHB3 as mediators of these effects of SREBP-1a and -1c in muscle. Both repressors are SREBP-1 target genes, and they affect the expression of numerous genes involved in the myogenic program. Our findings identify a new role for SREBP-1 transcription factors in muscle, thus linking the control of muscle mass to metabolic pathways.

The role of circCNIH4 in the adipocyte's effects on metastasis of breast cancer cells.

2020 ◽  
Vol 38 (15_suppl) ◽  
pp. e13086-e13086
Author(s):  
Xiu Chen ◽  
Jinhai Tang
Keyword(s):  
Breast Cancer ◽  
Wound Healing ◽  
Cell Invasion ◽  
Invasion And Migration ◽  
Non Invasive ◽  
In Vivo Experiments ◽  
And Migration ◽  
Mcf 7

e13086 Background: Obesity is associated with the risk of breast cancer(BCa) incidence and development. However, biological changes in obesity BCa individuals are still uncertain. Nowadays, circCNIH4, one of novel non-coding RNAs, was found to be a non-invasive biomarker in cancers. Methods: We verified the cancer-promoting role of obesity in BCa patients by comparing BMI indexes of 33 BCa and 44 benign tumor patients. Then we cocultured viscera adipose cells(HPA-v) and BCa cells(MCF-7/H and MDA-MB-231/H) to confirm the function of adipocytes on metastasis of BCa cells through wound healing, transwell assays. In vivo experiments were also performed. We analyzed the expression level of circCNIH4 in MCF-7/H, MDA-MB-231/H and different subtypes of BCa cells by quantitative polymerase chain reaction. Simultaneously, we identified inhibited effects of circCNIH4 on metastasis of BCa cells by wound healing, transwell assays and verified the location of circCNIH4 by FISH. Luciferase Assay was used to detect harbored miRNA. Rescue experiments were then applied. Results: We found the BMI of BCa patients(24.37±2.51) was much higher than benign patients(22.97±2.91). Metastasis of BCa cells were obviously promoted after in vitro and in vivo experiments. Then we found the expression of circCNIH4 in MCF-7/H and MDA-MB-231/H were down-regulated 0.71 and 0.52 than that in MCF-7 and MDA-MB-231. Also, circCNIH4 was positively correlated with less aggressive types of BCa cells. Overexpression of circCNIH4 in MDA-MB-231 could suppress cell invasion and migration, while silencing of it in MCF-7 promoted cell invasion and migration. The FISH assay demonstrated that circCNIH4 mainly located in the cytoplasm and might function as a “sponge” for miRNA. MiR-135b functioned as a tumor promoter gene from data of 93 BCa patients (HR = 2.27; 1.01 − 5.12), and it could be captured by circCNIH4 via luciferase and rescued assays. Conclusions: In this study, we revealed that BMI or viscera adipocytes could deteriorate prognosis of BCa and circCNIH4 could be a novel biomarker for non-invasive BCa. In details, circCNIH4 mainly suppressed the adipocyte's pro-metastasis effects on BCa by capturing miR-135b.

scholarly journals SCAP/SREBP pathway is required for the full steroidogenic response to cyclic AMP

2016 ◽  
Vol 113 (38) ◽  
pp. E5685-E5693 ◽  
Author(s):  
Masami Shimizu-Albergine ◽  
Brian Van Yserloo ◽  
Martin G. Golkowski ◽  
Shao-En Ong ◽  
Joseph A. Beavo ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Leydig Cells ◽  
De Novo ◽  
Regulatory Element ◽  
De Novo Synthesis ◽  
Intracellular Lipid ◽  
Element Binding Protein ◽  
Short Palindromic Repeat ◽  
Sterol Regulatory Element

Luteinizing hormone (LH) stimulates steroidogenesis largely through a surge in cyclic AMP (cAMP). Steroidogenic rates are also critically dependent on the availability of cholesterol at mitochondrial sites of synthesis. This cholesterol is provided by cellular uptake of lipoproteins, mobilization of intracellular lipid, and de novo synthesis. Whether and how these pathways are coordinated by cAMP are poorly understood. Recent phosphoproteomic analyses of cAMP-dependent phosphorylation sites in MA10 Leydig cells suggested that cAMP regulates multiple steps in these processes, including activation of the SCAP/SREBP pathway. SCAP [sterol-regulatory element-binding protein (SREBP) cleavage-activating protein] acts as a cholesterol sensor responsible for regulating intracellular cholesterol balance. Its role in cAMP-mediated control of steroidogenesis has not been explored. We used two CRISPR (clustered regularly interspaced short palindromic repeat)-Cas9 (CRISPR associated protein 9) knockout approaches to test the role of SCAP in steroidogenesis. Our results demonstrate that SCAP is required for progesterone production induced by concurrent inhibition of the cAMP phosphodiesterases PDE4 and PDE8. These inhibitors increased SCAP phosphorylation, SREBP2 activation, and subsequent expression of cholesterol biosynthetic genes, whereas SCAP deficiency largely prevented these effects. Reexpression of SCAP in SCAP-deficient cells restored SREBP2 protein expression and partially restored steroidogenic responses, confirming the requirement of SCAP–SREBP2 in steroidogenesis. Inhibitors of 3-hydroxy-3-methylglutaryl-Coenzyme A reductase and isoprenylation attenuated, whereas exogenously provided cholesterol augmented, PDE inhibitor-induced steroidogenesis, suggesting that the cholesterol substrate needed for steroidogenesis is provided by both de novo synthesis and isoprenylation-dependent mechanisms. Overall, these results demonstrate a novel role for LH/cAMP in SCAP/SREBP activation and subsequent regulation of steroidogenesis.

scholarly journals Advanced glycation end products promote hepatosteatosis by interfering with SCAP-SREBP pathway in fructose-drinking mice

2013 ◽  
Vol 305 (6) ◽  
pp. G398-G407 ◽  
Author(s):  
Raffaella Mastrocola ◽  
Massimo Collino ◽  
Mara Rogazzo ◽  
Claudio Medana ◽  
Debora Nigro ◽  
...  
Keyword(s):  
Advanced Glycation End Products ◽  
De Novo ◽  
Regulatory Element ◽  
Plasma Lipid ◽  
De Novo Lipogenesis ◽  
Advanced Glycation ◽  
Sugary Drinks ◽  
Glycation End Products ◽  
End Products

Clinical studies have linked the increased consumption of fructose to the development of obesity, dyslipidemia, and impaired glucose tolerance, and a role in hepatosteatosis development is presumed. Fructose can undergo a nonenzymatic reaction from which advanced glycation end products (AGEs) are derived, leading to the formation of dysfunctional, fructosylated proteins; however, the in vivo formation of AGEs from fructose is still less known than that from glucose. In the present study C57Bl/6J mice received 15% (wt/vol) fructose (FRT) or 15% (wt/vol) glucose (GLC) in water to drink for 30 wk, resembling human habit to consume sugary drinks. At the end of the protocol both FRT- and GLC-drinking mice had increased fasting glycemia, glucose intolerance, altered plasma lipid profile, and marked hepatosteatosis. FRT mice had higher hepatic triglycerides deposition than GLC, paralleled by a greater increased expression and activity of the sterol regulatory element-binding protein 1 (SREBP1), the transcription factor responsible for the de novo lipogenesis, and of its activating protein SCAP. LC-MS analysis showed a different pattern of AGE production in liver tissue between FRT and GLC mice, with larger amount of carboxymethyl lysine (CML) generated by fructose. Double immunofluorescence and coimmunoprecipitation analysis revealed an interaction between CML and SCAP that could lead to prolonged activation of SREBP1. Overall, the high levels of CML and activation of SCAP/SREBP pathway associated to high fructose exposure here reported may suggest a key role of this signaling pathway in mediating fructose-induced lipogenesis.

scholarly journals MicroRNA-33 encoded by an intron of sterol regulatory element-binding protein 2 (Srebp2) regulates HDL in vivo

2010 ◽  
Vol 107 (40) ◽  
pp. 17321-17326 ◽  
Author(s):  
T. Horie ◽  
K. Ono ◽  
M. Horiguchi ◽  
H. Nishi ◽  
T. Nakamura ◽  
...  
Keyword(s):  
Binding Protein ◽  
Regulatory Element ◽  
Element Binding Protein ◽  
Sterol Regulatory Element
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