Project description:In several developmental lineages, an increase in expression of the MYC proto-oncogene drives the transition from quiescent stem cells to transit amplifying cells. The mechanism by which MYC restricts self-renewal of adult stem cells is unknown. Here, we show that MYC activates a stereotypic transcriptional program of genes involved in protein translation and mitochondrial biogenesis in mammary epithelial cells and indirectly inhibits the YAP/TAZ co-activators that are essential for mammary stem cell self-renewal. We identify a phospholipase of the mitochondrial outer membrane, PLD6, as the mediator of MYC activity. PLD6 mediates a change in the mitochondrial fusion/fission balance that promotes nuclear export of YAP/TAZ in a LATS- and RHO-independent manner. Mouse models and human pathological data confirm that MYC suppresses YAP/TAZ activity in mammary tumors. PLD6 is also required for glutaminolysis, arguing that MYC-dependent changes in mitochondrial dynamics balance cellular energy metabolism with the self-renewal potential of adult stem cells. ChIP-Seq experiments for MYC-HA (HA-IP) performed in IMEC primary breast epithelial cells. Input-samples were sequenced as controlls.
Project description:In several developmental lineages, an increase in expression of the MYC proto-oncogene drives the transition from quiescent stem cells to transit amplifying cells. The mechanism by which MYC restricts self-renewal of adult stem cells is unknown. Here, we show that MYC activates a stereotypic transcriptional program of genes involved in protein translation and mitochondrial biogenesis in mammary epithelial cells and indirectly inhibits the YAP/TAZ co-activators that are essential for mammary stem cell self-renewal. We identify a phospholipase of the mitochondrial outer membrane, PLD6, as the mediator of MYC activity. PLD6 mediates a change in the mitochondrial fusion/fission balance that promotes nuclear export of YAP/TAZ in a LATS- and RHO-independent manner. Mouse models and human pathological data confirm that MYC suppresses YAP/TAZ activity in mammary tumors. PLD6 is also required for glutaminolysis, arguing that MYC-dependent changes in mitochondrial dynamics balance cellular energy metabolism with the self-renewal potential of adult stem cells.
Project description:In several developmental lineages, an increase in expression of the MYC proto-oncogene drives the transition from quiescent stem cells to transit amplifying cells. The mechanism by which MYC restricts self-renewal of adult stem cells is unknown. Here, we show that MYC activates a stereotypic transcriptional program of genes involved in protein translation and mitochondrial biogenesis in mammary epithelial cells and indirectly inhibits the YAP/TAZ co-activators that are essential for mammary stem cell self-renewal. We identify a phospholipase of the mitochondrial outer membrane, PLD6, as the mediator of MYC activity. PLD6 mediates a change in the mitochondrial fusion/fission balance that promotes nuclear export of YAP/TAZ in a LATS- and RHO-independent manner. Mouse models and human pathological data confirm that MYC suppresses YAP/TAZ activity in mammary tumors. PLD6 is also required for glutaminolysis, arguing that MYC-dependent changes in mitochondrial dynamics balance cellular energy metabolism with the self-renewal potential of adult stem cells.
Project description:In several developmental lineages, an increase in expression of the MYC proto-oncogene drives the transition from quiescent stem cells to transit amplifying cells. The mechanism by which MYC restricts self-renewal of adult stem cells is unknown. Here, we show that MYC activates a stereotypic transcriptional program of genes involved in protein translation and mitochondrial biogenesis in mammary epithelial cells and indirectly inhibits the YAP/TAZ co-activators that are essential for mammary stem cell self-renewal. We identify a phospholipase of the mitochondrial outer membrane, PLD6, as the mediator of MYC activity. PLD6 mediates a change in the mitochondrial fusion/fission balance that promotes nuclear export of YAP/TAZ in a LATS- and RHO-independent manner. Mouse models and human pathological data confirm that MYC suppresses YAP/TAZ activity in mammary tumors. PLD6 is also required for glutaminolysis, arguing that MYC-dependent changes in mitochondrial dynamics balance cellular energy metabolism with the self-renewal potential of adult stem cells. RNA-Seq Experiments in 2 different primary breast epithelial cell lines (HMLE, which were sorted according to CD44/CD24 surface markers & unsorted IMEC). Both cell lines expressed a doxycycline-inducible version of MYC. For the HMLE cell line DGE analysis was performed for the uninduced (EtOH) situation, comparing CD44high vs CD44 low and for the induced situation Dox vs. EtOH for the CD44high population. For the IMEC cell line DGE was performed by comparing Dox-treated populations expressing either Dox-inducible MYC or a vector control which allows to filter out potential effects due to doxycycline treatment.
Project description:The crosstalk between tumor cells and the adjacent normal epithelium contributes to cancer progression, but its regulators have remained elusive. Here, we show that breast cancer cells maintained in hypoxia release small extracellular vesicles (sEV) that activate mitochondrial dynamics, stimulate mitochondrial movements and promote organelle accumulation at the cortical cytoskeleton in normal mammary epithelial cells. This results in Akt activation, membrane focal adhesion turnover and increased epithelial cell migration. RNA-Seq profiling identified Integrin-Linked Kinase (ILK) as the most upregulated pathway in sEV-treated epithelial cells and genetic or pharmacologic targeting of ILK reversed mitochondrial reprogramming and suppressed sEV-induced cell movements. In a three-dimensional model of mammary gland morphogenesis, sEV treatment induced hallmarks of malignant transformation, with deregulated cell death/cell proliferation, loss of apical-basal polarity and appearance of epithelial-to-mesenchymal transition (EMT) markers. Therefore, sEV released by hypoxic breast cancer cells reprogram mitochondrial dynamics and induce oncogenic changes in a normal mammary epithelium
Project description:Purpose: discover the downstream pathways and the mechanism of target activation by the p53:Myc axis in normal mammary and cancer stem cells Methods: we performed ChIPseq experiments from NMuMG cells grown in adhesion under standard conditions Results: the p53:Myc axis orchestrates its transcriptional response in mammary-epithelial cells via a dual and overlapping mechanism: i) a tightly controlled epistasis driven by p53 and executed by Myc, and ii) a co-operative double occupancy of their downstream effectors at different regulatory regions
Project description:c-MYC oncogene is one of the driver lesions in many types of cancer. Among breast cancers, triple negative subtype (TNBC) is characterised by high aggressivness and is associated with high transcriptional activity of MYC. MMTV-cMYC mouse model, in which ectopic expression of c-MYC is driven by mouse mammary tumour virus promoter, is a widely used model of MYC-driven breast cancer. MMTV-cMYC mice develop tumours in the mammary gland(s) at ages ranging from 6 to 10 months. MYC regulates activity of multiple processes including cell cyle, proliferation, metabolism, protein translation, inflammation and apoptosis among others. Previous studies demonstrated that MMTV-cMYC tumours are very heterogeneous. However, how different procecesses regulated by MYC contribute to different steps of the transformation process and tumour development is not known. To evaluate how the expression of genes changes from the initiation of transformation process by ectopic expression of c-MYC in mammary gland epithelial cells to the development of tumours, we perfomed RNAseq analysis of tissues collected from mammary glands and tumours of MMTV-cMYC mice of different ages. Wild type age-matched littermates were used as controls.
Project description:Epithelial-mesenchymal transition (EMT) involves profound changes in cell morphology, driven by transcriptional and epigenetic reprogramming. However, it emerges that translation and the ribosome composition play also key role in establishing physio-pathological phenotypes. Using genome-wide analyses, we report significant rearrangement of the translational landscape and machinery during EMT. Specifically, a mesenchymal cell line overexpressing the EMT transcription factor ZEB1 shows alterations in translational reprogramming and fidelity. Considering the change in translational activity of ZEB1-overexpressing mesenchymal cells, including in fidelity activity, we sought for changes in ribosome composition. We thus performed a riboproteome approach, i.e., mass spectrometry (MS)-based quantitative proteomic analysis of purified cytoplasmic ribosomes to highlight any change in relative amount of individual ribosomal proteins between wild-type and ZEB1-overexpressing human mammary epithelial cells.