Project description:Cancer-associated fibroblasts (CAFs), the principal components of tumor microenvironment, play multiple roles in breast cancer onset and progression. While their impact is widely accepted, treatment options to target CAFs in clinical practice were not yet well established. The nuclear receptor superfamily encompasses a druggable class of molecules, expressed in various stroma and parenchymal cell types, with the interesting therapeutic potential to modulate the reactive microenvironment. Having already addressed the oncosuppressive role of the nuclear Farnesoid X Receptor (FXR) in mammary epithelial cancer cells, the present study is aimed to assess the function of FXR in CAFs and evaluate whether its activation may affect their tumor-promoting features.
Project description:The Farnesoid-X-Receptor (FXR) is a nuclear receptor (NR) known to obligately heterodimerize with Retinoid-X-Receptor (RXR). FXR is expressed as four isoforms (α1-α4) that drive transcription from IR-1 (inverted repeat-1) DNA motifs. More recently, FXR isoforms α2/α4 were found to activate transcription predominantly from non-canonical ER-2 (everted repeat-2) DNA motifs, mediating most metabolic effects of general FXR activation.Here, we explored whether co-occupancy of FXR and RXR in the mouse liver has an influence on DNA motif binding preference. We found RXR acts as a molecular switch, promoting FXRα2 activation from IR-1 instead of ER-2 motifs. Our results showcase FXR as the first NR with RXR-dependent and independent modes of activation, highlighting a potential new layer of complexity for other RXR-heterodimerizing NRs.
Project description:We co-cultured primary cultured CAF (CAF-P), which promotes progression more actively, and CAF (CAF-D), which have less cancer-promoting properties, with OSCC cells, and analyzed the differential secretion through antibody microarray.
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.
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
Project description:Compare the difference between pairwise aNOF and CAF samples for two patients patient #225: aNOF #225 vs CAF #225 patient #248: aNOF #248 vs CAF #248
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.
Project description:Gene expression profiling of CAF co-cultured with human oral squamous cell carcinoma (OSCC) cells compared with mono-cultured CAF. To identify key molecular regulators expressed by carcinoma-associated fibroblasts (CAF) that promote cancer cell invasion, microarrays were performed by comparing co-cultured OSCC cells and CAF with monoculture controls. comparison 1: CAF co-cultured with OSCC vs. mono-cultured CAF comparison 2: OSCC co-cultured with CAF vs. mono-cultured OSCC 1.7X10(5) YD-10B OSCC cells and 1.7X10(5) CAF were seeded in the upper chamber and lower chamber, respectively, of 6-transwell plates containing collagen-coated 1 micrometer pore transmembrane filters (Becton Dickinson, Franklin Lakes, NJ, USA). Monoculture control samples were generated by culturing only CAF or OSCC on the same side of the filter as in the co-culture design.
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.
Project description:To investigate the role of nuclear receptor FXR during hepatocarcinogenesis, HepG2 cels and SK-Hep-1 cells were transfected with lentiviral mediated FXR overexpressive vector or the negative control. After the cells were treated with FXR agonist GW4064 2uM for 24 h, and total RNA were isolated for detection of gene expression .