FXR Agonism with Bile Acid Mimetic Reduces Pre-Clinical Triple-Negative Breast Cancer Burden
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1096356 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR28560219_1.fastq.gz | Fastqsanger.gz | |||
| SRR28560219_2.fastq.gz | Fastqsanger.gz | |||
| SRR28560220_1.fastq.gz | Fastqsanger.gz | |||
| SRR28560220_2.fastq.gz | Fastqsanger.gz | |||
| SRR28560221_1.fastq.gz | Fastqsanger.gz |
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Project description:Breast cancer (BC) is the most common malignancy and the leading cause of cancer mortality in women. It is possible that signals arising from the gut microbiome are protective in BC. We used common drugs designed to turn on pathways to mimic one major signal coming from gut microbes, namely bile acids. Taking advantage of a drug called Ocaliva, which is commercially available for another disease, we repurposed this drug to test its anti-cancer potential. Ocaliva worked on a specific protein target called FXR to reduce tumor growth and kill cancer cells. In contrast, a similar drug that targets a different protein called TGR5 was not effective in killing cancer cells. Taken together, these findings suggest that using Ocaliva or other bile acid signals derived from the gut microbiome to target the protein FXR could be an important new therapeutic strategy for individuals with aggressive BC.
2024-04-04 | GSE263255 | GEO
Project description:The Farnesoid-X-Receptor (FXR) is a class II nuclear receptor (NR), a class that obligately heterodimerizes with the Retinoid-X-Receptor (RXR). FXR is expressed as 4 isoforms (α1-α4) activated by bile acids that drive transcription from response elements IR-1 (inverted repeat-1). We recently showed that FXR isoforms α2 and α4 bind to non-canonical response elements ER-2 (everted repeat-2), thereby increasing mitochondrial respiratory capacity and limiting de novo lipogenesis. Binding to ER-2 motifs in mouse liver organoids represented 89% of all FXR genome wide binding. However, mechanistic differences in FXR binding and activation from these two response elements remained unexplored. Using DNA pull down followed by mass-spectrometry, we show that RXR is not involved in FXR binding to ER-2 response elements. Instead, RXR inhibited FXR binding and activation from these elements in luciferase reporters. Genome wide, RXR-lacking FXR binding sites showed higher enrichment for ER-2 motifs in mouse liver. Pharmacological and mutational abrogation of FXR-RXR heterodimerization specifically retained ER-2 transactivation capacities in luciferase reporters and HepG2 cells. Transcriptome-wide, 25% of FXR targets were inhibited upon RXR overexpression, but specifically activated by a novel heterodimerization-deficient mutant FXRα2L434R. These genes were ER-2 responsive and were involved in lipid metabolism and ammonia detoxification. In conclusion, we discovered that RXR is not required and even inhibits binding of FXRα2 to ER-2. Thus, whereas FXR α1 and α3 seem to be genuine class II NR, FXRα2 and α4 are facultative class II at ER-2 motifs. This novel feature holds promise to exploit and tailor therapeutic responses to FXR agonism.
2024-11-12 | PXD047930 | Pride
Project description:The purpose of this study was to elucidate potential effects of fxr mutation on the functional specification of intestinal epithelial cells. To do this, we sorted GFP-positive cells from TgBAC(cldn15la:GFP) transgenics of either fxr+/+ or fxr-/- fish larvae and subjected them to 10X Genomics single-cell RNA-seq. Our results uncovered the requirement of fxr in gene expression and differentiation among multiple intestinal epithelial cell types.
2021-04-30 | GSE173570 | GEO
Project description:Farnesoid-X-Receptor (FXR) plays a central role in maintaining bile acid (BA) homeostasis by transcriptional control of numerous enterohepatic genes, including intestinal FGF19, a hormone that strongly represses hepatic BA synthesis. How activation of the FGF19 receptor at the membrane is transmitted to the nucleus for transcriptional regulation of BA levels and whether FGF19 signaling posttranslationally modulates function of FXR remain largely unknown. Here we show that FXR is phosphorylated at Y67 by non-receptor tyrosine kinase, Src, in response to postprandial FGF19, which is critical for its nuclear localization and transcriptional regulation of BA levels. Liver-specific expression of phospho-defective Y67F-FXR or Src-downregulation in mice result in impaired homeostatic responses to acute BA feeding, and exacerbate cholestatic pathologies upon drug-induced hepatobiliary insults. Also, the hepatic FGF19-Src-FXR pathway is defective in primary biliary cirrhosis patients. This study identifies Src-mediated FXR phosphorylation as a potential therapeutic target and biomarker for BA-related enterohepatic diseases.
2018-04-27 | GSE113707 | GEO
Project description:Identified genes deregulated in mouse primary hepatocytes after modulation of expression/activity of FOXA2 and FXR in glucagon or insulin state
2018-08-16 | GSE113549 | GEO
Project description:Bile acid (BA) homeostasis is maintained through a feedback loop operated by the nuclear hormone receptors FXR and SHP. Here we show that contrary to the current models placing FXR upstream of SHP in a linear regulatory pathway, the phenotypic consequence of the combined loss of both receptors is much more severe than the relatively modest impact of the loss of either Fxr or Shp alone. This is highlighted by the dramatic elevation of hepatic and serum BA levels in the double knockout (DKO) mice as early as three weeks of age coupled with a commensurate increase in Cyp7A1 expression and alterations in BA homeostatic genes. In addition, we find several genes necessary for C21 steroid biosynthetic pathway as novel targets for FXR and SHP. The elevated BAs result in severe hepato-pathology but the DKO mice surprisingly do not develop complete liver failure and live for over a year. Their survival is accompanied by an adaptive proliferation of the resident liver progenitor cell population, known as oval cells. Overall, these data demonstrate that FXR and SHP function coordinately to maintain BA homeostasis, and identify DKO mice as a novel genetic model for juvenile cholestatic disorders and for oval cell activation. Liver samples collected from FXR-/-, SHP-/-, and FXR-/-/SHP-/- animals at 3 or 5 weeks were hybridized to Illumina mouse REF-8 v1.1 arrays in duplicate.
2010-12-10 | E-GEOD-20599 | biostudies-arrayexpress
Project description:The systemic expression of the bile acid (BA) sensor farnesoid X receptor (FXR) has led to promising new therapies targeting cholesterol metabolism, triglyceride production, hepatic steatosis and biliary cholestasis. In contrast to systemic therapy, bile acid release during a meal selectively activates intestinal FXR. By mimicking this tissue-selective effect, the gut-restricted FXR agonist fexaramine (Fex) robustly induces enteric fibroblast growth factor 15 (FGF15), leading to alterations in BA composition, but does so without activating FXR target genes in the liver. However, unlike systemic agonism, we find that Fex reduces diet-induced weight gain, body-wide inflammation and hepatic glucose production, while enhancing thermogenesis and browning of white adipose tissue (WAT). These pronounced metabolic improvements suggest tissue-restricted FXR activation as a new approach in the treatment of obesity and metabolic syndrome.
| S-EPMC4320010 | biostudies-literature
Project description:Glucagon, an essential regulator of glucose and lipid metabolism, also promotes weight loss, in part through potentiation of fibroblast-growth factor 21 (FGF21) secretion. However, FGF21 is only a partial mediator of metabolic actions ensuing from GcgR-activation, prompting us to search for additional pathways. Intriguingly, chronic GcgR agonism increases plasma bile acid levels. We hypothesized that GcgR agonism regulates energy metabolism, at least in part, through farnesoid X receptor (FXR). To test this hypothesis, we studied whole body and liver-specific FXR knockout (FXR∆liver) mice. Chronic GcgR agonist (IUB288) administration in diet-induced obese (DIO) Gcgr, Fgf21 and Fxr whole body or liver-specific knockout (∆liver) mice failed to reduce body weight (BW) when compared to wildtype (WT) mice. IUB288 increased energy expenditure and respiration in DIO WT mice, but not FXR∆liver mice. GcgR agonism increased [14C]-palmitate oxidation in hepatocytes isolated from WT mice in a dose-dependent manner, an effect blunted in hepatocytes from FXR∆liver mice. Our data clearly demonstrate that control of whole body energy expenditure by GcgR agonism requires intact FXR signaling in the liver. This heretofore-unappreciated aspect of glucagon biology has implications for the use of GcgR agonism in the therapy of metabolic disorders.
2019-08-16 | GSE135881 | GEO
Project description:Acetylation of transcriptional regulators is normally dynamically regulated by nutrient status but is often persistently elevated in nutrient-excessive obesity conditions. We investigated the functional consequences of such aberrantly elevated acetylation of the nuclear receptor FXR as a model. Proteomic studies identified K217 as the FXR acetylation site in diet-induced obese mice. In vivo studies utilizing acetylation-mimic and -defective K217 mutants and gene expression profiling revealed that FXR acetylation increased proinflammatory gene expression, macrophage infiltration, and liver cytokine and triglyceride levels, impaired insulin signaling, and increased glucose intolerance. Mechanistically, acetylation of FXR blocked its interaction with the SUMO ligase PIASy and inhibited SUMO2 modification at K277, resulting in activation of inflammatory genes. SUMOylation of agonist-activated FXR increased its interaction with NF-κB but blocked that with RXRα, so that SUMO2-modified FXR was selectively recruited to and trans-repressed inflammatory genes without affecting FXR/RXRα target genes. A dysregulated Acetyl/SUMO switch of FXR in obesity may serve as a general mechanism for diminished anti-inflammatory response of other transcriptional regulators and provide potential therapeutic and diagnostic targets for obesity-related metabolic disorders. FXR-WT or the FXR-K217Q mutant was expressed in lean mice and FXR-WT or the FXR-K217R mutant was expressed in obese mice by adenoviral infection. One week after infection, mice were treated with GW4064 (30 mg/kg in corn oil) overnight before sacrifice and hepatic expression was analyzed by Illumina microarray.
2014-10-17 | E-GEOD-62414 | biostudies-arrayexpress
Project description:The serine or threonine between two zinc fingers of the DNA binding domains (DBD) is highly conserved in a majority of nuclear receptors. In the present study, we focused on the serine 154 of farnesoid X receptor (FXR). To determine the influence of phosphomimetic or non-phosphomimetic mutation for FXR on gene expressions, we employed cDNA microarray analysis using COS-1 cells which ectopically express FXR S154A or FXR S154D with DMSO or CDCA.
2017-05-24 | GSE82278 | GEO