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:FXR (Farnesoid X Receptor), also known as Nr1h4, is a transcription factor who is also one of the bile acid receptor has been reported to be widely involved in regulating blood glucose, bile acid, and the apoptosis of hepatocyte. We have been studing the key role of FXR in Type 2 Diabetes, which can regulate the insulin secretion or even the apoptosis of β-cells. Thus,we measured the gene expression in the islets of FXR KO mice. Our data shows the abnormal expressed gene between the FXR KO mice and the Control group, which may be regulated by FXR. It will be significant promotion for the research in mechanism of FXR regulating the insulin secretion and apoptosis of β-cells.
2024-12-12 | GSE279682 | 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:Obstruction of bile flow results in bacterial proliferation and mucosal injury in the small intestine that can lead to the translocation of bacteria across the epithelial barrier and systemic infection. These adverse effects of biliary obstruction can be inhibited by administration of bile acids. Here we show that the farnesoid X receptor (FXR), a nuclear receptor for bile acids, induces genes involved in enteroprotection and inhibits bacterial overgrowth and mucosal injury in ileum caused by bile duct ligation. Mice lacking FXR have increased ileal levels of bacteria and a compromised epithelial barrier. These findings reveal a central role for FXR in protecting the distal small intestine from bacterial invasion and suggest that FXR agonists may prevent epithelial deterioration and bacterial translocation in patients with impaired bile flow. In this report we have examined the role of FXR in the ileum. We demonstrate that it plays a crucial role in preventing bacterial overgrowth and maintaining the integrity of the intestinal epithelium
2012-07-19 | GSE39507 | GEO
Project description:The farnesoid X receptor (FXR) is a nuclear receptor activated by bile acids that regulates bile acid metabolism, glucose and cholesterol homeostasis. FXR is expressed as four isoforms (α1-4), and their relative abundance is tissue specific. Human livers express predominantly FXR isoforms α1 and α2. From mouse studies we know that the FXR agonist obeticholic acid (OCA) regulates expression of many genes in the liver. However, there is currently no data on the effects of OCA on FXR isoform selective gene regulation. This is particularly relevant since the relative FXR isoform amounts in the liver are regulated by general bioenergetic cues (Correia JC et al. 2015). In this study we investigate the effect of variations in FXR isoforms α1 or α2 expression on HepG2 cell lines response to treatment with OCA.
2020-07-27 | GSE133659 | 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 farnesoid X receptor (FXR) is a nuclear receptor activated by bile acids and regulates bile acid metabolism, glucose and cholesterol homeostasis. From mouse studies we know that the novel FXR agonist obeticholic acid (OCA) regulates expression of many genes in the liver, but there is currently no data on the effects of OCA on human liver gene expression. This is especially relevant since the novel FXR agonist OCA is currently tested in clinical trials for the treatment of several diseases, such as nonalcoholic steatohepatitis (NASH), nonalcoholic fatty liver disease (NAFLD) and Type 2 Diabetes. In this study we investigate the effect of OCA treatment on gene expression profiles and localization of FXR to the genome in relevant liver samples. ChIP-Seq for FXR in Liver tissue from 2 male mice treated with OCA/INT-747 (10mg/kg/day) and 2 male mice treated with vehicle (1% methyl cellulose).
2016-01-27 | E-GEOD-73624 | biostudies-arrayexpress
Project description:X-box binding protein 1 (XBP1) is a key component of the unfolded protein response that is activated in response to ER stress. Farnesoid X receptor (FXR) null (Fxr-/-) mice have elevated bile acid levels and progressive liver injury. Hepatic XBP1 pathway is activated in older Fxr-/- mice. This project is to investigate the role of liver XBP1 in Fxr-/- mice.
2022-09-19 | GSE201902 | GEO
Project description:Specific bile acids are potent signaling molecules that modulate metabolic pathways affecting lipid, glucose and bile acid homeostasis, and the microbiota. Bile acids are synthesized from cholesterol in the liver, and the key enzymes involved in bile acid synthesis (Cyp7a1, Cyp8b1) are regulated transcriptionally by the nuclear receptor FXR. We have identified an FXR-regulated pathway upstream of a transcriptional repressor that controls multiple bile acid metabolism genes. We identify MafG as an FXR target gene and show that hepatic MAFG overexpression represses genes of the bile acid synthetic pathway and modifies the biliary bile acid composition. In contrast, loss-of-function studies using MafG(+/-) mice causes de-repression of the same genes with concordant changes in biliary bile acid levels. Finally, we identify functional MafG response elements in bile acid metabolism genes using ChIP-seq analysis. Our studies identify a molecular mechanism for the complex feedback regulation of bile acid synthesis controlled by FXR.
2016-02-04 | GSE77529 | GEO