Project description:Despite recent advances in genomic profiling techniques, the precise mechanisms controlling GBM subtypes and their plasticity are not fully unraveled. Here,using transcriptomic data of patient derived stem cell lines we found that FOSL1 is a master regulator of the MES subtype. Depletion of FOSL1 resulted in loss of themesenchymal gene signature (MGS) in mouse Kras-mutant neural stem cells and in human brain tumor stem cells.
Project description:To explore genome-wide alteration MED1 and FOSL1 after depletion of FOSL1, we performed chromatin immunoprecipitation sequencing (ChIP-seq) of SCC1 cells to examine genome-wide recruitment of MED1 and FOSL1 following FOSL1 knockdown. Depletion of FOSL1 led to dramatically loss of the recruitment of MED1 and FOSL1 at a cohort of key oncogenes associate with tumorigenesis and metastasis.
Project description:Glioblastomas (GBM) are driven by malignant neural stem-like cells that display extensive heterogeneity and phenotypic plasticity, which drives tumour progression and therapeutic resistance. Here we show that the nodal extracellular matrix-cell adhesion protein integrin-linked kinase (ILK) is a key determinant of phenotypic plasticity and the mesenchymal-like, invasive cell state in mouse GBM stem cells. We found that an ILK-STAT3 signalling pathway is required for plasticity that enables the transition of GBM stem cells to an astrocyte-like state both in vitro andin vivo. GBM cells genetically depleted of ILK become predominantly stabilised in a transcriptionally-defined progenitor-like state that is characterised by lack of response to differentiation cues and constitutive proliferation. Loss of ILK or interference with STAT3 impairs differentiation potential, reducing phenotypic plasticity of tumour cell populations; additionally, ILK loss causes a mesenchymal- to epithelial-like morphological transition and suppression of malignancy-associated features. Our work defines ILK as a central regulator of multiple GBM phenotypes including phenotypic plasticity and mesenchymal state.
Project description:The differentiation of Th17 cells is controlled by a complex network of transcription factors (TFs), including FOS and JUN proteins of the AP-1 family. The FOS-like proteins, FOSL1 and FOSL2 have recently been reported to control Th17 responses. The molecular mechanisms dictating their roles, however, are unclear. Moreover, although the functions of AP-1 TFs are largely governed by their protein-protein interactions, these are also poorly characterized in this milieu. Using affinity purification in combination with mass-spectrometry we established the first interactomes of FOSL1 and FOSL2 in human Th17 cells. In addition to their known interactions with JUN proteins, our analysis identified several novel binding partners of FOSL factors. Gene ontology analysis revealed RNA binding was enriched as the major functionality for FOSL1 and FOSL2 associated proteins, thereby suggesting possible mechanistic links that have not been studied before. Intriguingly, 29 interactors were found to be shared between FOSL1 and FOSL2, which included crucial regulators of Th17-fate. These findings, including unique and shared interactions, were validated using parallel reaction monitoring targeted mass-spectrometry (PRM-MS), with additional measurements with other laboratory methods. Overall, this study provides key insights into interaction-based signalling mechanisms of FOSL1 and FOSL2, which potentially control Th17 cell-development and associated pathologies.
Project description:Peripheral glial Schwann cells switch to a repair state after nerve injury, proliferate to supply lost cell population, migrate to form regeneration tracks, and generates a permissive microenvironment for nerve regeneration. Exploring essential regulators of the repair responses of Schwann cells may benefit the clinical treatment for peripheral nerve injury. In the present study, FOSL1 regulates Schwann cell phenotype modulation and provided a novel therapeutic approach to orchestrate the regeneration and functional recovery of injured peripheral nerves.
Project description:In hemochorial placentation, trophoblast stem cells differentiate into multiple lineages to aquire specific functions, such as invasive and endocrine phenotype. FOSL1 has been identified as a key regulator for trophoblast differentiation. We used microarray to detail mechanisms underlying FOSL1 signaling pathway in trophoblast differentiation. 3 replicates of differentiated Rcho1 TS cells expressing control shRNA; 3 replicates of differentiated Rcho1 TS cells expressing Fosl1 shRNA
Project description:SUMMARY Despite numerous genome-wide association studies involving glioblastoma (GBM), few therapeutic targets have been identified for this disease. Using patient derived glioma sphere cultures (GSCs), we have found that a subset of the proneural (PN) GSCs undergo transition to a mesenchymal (MES) state in a TNFa/NFkB dependent manner with an associated enrichment of CD44 sub-populations and radio-resistant phenotypes. To the contrary, MES GSCs exhibit constitutive NFkB activation, CD44 enrichment and radio-resistance. Patients whose tumors exhibit a higher MES metagene, increased expression of CD44, or activated NFkB were associated with poor radiation response and shorter survival. Our results indicate that NFkB activation mediated MES differentiation and radiation resistance presents an attractive therapeutic target for GBM. SIGNIFICANCE In this study, we show plasticity between the proneural (PN) and mesenchymal (MES) transcriptome signatures observed in glioblastoma (GBM). Specifically, we show that PN glioma sphere cultures (GSCs) can be induced to a MES state with an associated enrichment of CD44 expressing cells and a gain of radio-resistance, which we implicate as NFkB- dependent. Newly diagnosed GBM samples show a direct correlation between radiation response, higher MES metagene, CD44 expression, and NFkB activation. This correlation is also observed in the subset of GBM samples that do not exhibit IDH1 mutation, a favorable prognostic marker. Our results uncover a previously unknown link between subtype plasticity that is regulated by NFkB. Inhibition of NFkB activation can directly impact radio-resistance and presents an attractive therapeutic target for GBM. 4 treatments