Project description:Alterations that perturb differentiation and cell state transitions can lead to defects in development, function and the genesis of cancer. Studying cellular plasticity at high resolution and in real time has proven difficult using existing methods. Here, we use a quantitative approach to gain insights into cell state dynamics of normal mammary epithelial cells (MECs) and validate the model's predictions in vivo. In the absence of Slug/SNAI2, basal mammary progenitor cells transition into a luminal differentiation state, while luminal progenitor cells proliferate and expand; these changes result in abnormal mammary architecture and defects in tissue function. Loss of Slug also disrupts cellular plasticity leading to defects in tissue regeneration and the initiation of cancer. Mechanistically, Slug promotes cellular plasticity by recruiting the chromatin modifier, LSD1 (lysine specific demethylase 1), to promoters of lineage specific genes to represses transcription. Together, these finding demonstrate that Slug is necessary for cellular adaptation during tissue development and regeneration, and that transitioning back into a more primitive stem-like state is a prerequisite for tumor initiation. reference x sample
Project description:Alterations that perturb differentiation and cell state transitions can lead to defects in development, function and the genesis of cancer. Studying cellular plasticity at high resolution and in real time has proven difficult using existing methods. Here, we use a quantitative approach to gain insights into cell state dynamics of normal mammary epithelial cells (MECs) and validate the model's predictions in vivo. In the absence of Slug/SNAI2, basal mammary progenitor cells transition into a luminal differentiation state, while luminal progenitor cells proliferate and expand; these changes result in abnormal mammary architecture and defects in tissue function. Loss of Slug also disrupts cellular plasticity leading to defects in tissue regeneration and the initiation of cancer. Mechanistically, Slug promotes cellular plasticity by recruiting the chromatin modifier, LSD1 (lysine specific demethylase 1), to promoters of lineage specific genes to represses transcription. Together, these finding demonstrate that Slug is necessary for cellular adaptation during tissue development and regeneration, and that transitioning back into a more primitive stem-like state is a prerequisite for tumor initiation.
Project description:Temporal expression profiling was utilized to define transcriptional regulatory pathways in vivo in a mouse muscle regeneration model. Potential downstream targets of MyoD were identified by temporal expression, promoter data base mining, and gel shift assays; Slug and calpain 6 were identified as novel MyoD targets. Slug, a member of the snail/slug family of zinc finger transcriptional repressors critical for mesoderm/ectoderm development, was further shown to be a downstream target by using promoter/reporter constructs and demonstration of defective muscle regeneration in Slug null mice.
Project description:Cancer stem cells (CSCs) are proposed to be responsible for metastatic dissemination and clinical relapse in a variety of cancers. Analogies between CSCs and normal tissue stem cells (SC) has led to the notion that CSCs often co-opt the normal SC program of their tissue-of-origin. The cell-biological program termed epithelial-mesenchymal transition (EMT) has been found to encourage entrance of normal and neoplastic mammary cells into the corresponding SC states. Using genetically engineered knock-in reporter mouse lines, we demonstrate that in the murine mammary lineage, the paralogous EMT-inducing transcription factors Snail and Slug, are selectively exploited by CSCs and normal SCs respectively. Slug, when expressed at physiological levels, only activates a partial EMT program and is dispensable in CSCs. In contrast, Snail drives a far more complete transition into the mesenchymal state and controls both tumor-initiation and metastatic dissemination. Consistent with their functional distinctions, Snail controls far more target genes than Slug, and their distinct functions are determined by their divergent N-terminal domains. Our findings underscore fundamental distinctions between the SC program operating in normal and neoplastic SCs, and hint for potential avenues of selective therapeutic elimination of breast CSCs. We sought to understand differential ability to activate the EMT program in breast cancer cells by transcription factors Snail and Slug. Hence, we mapped genome-wide Snail and Slug binding sites in murine MMTV-PyMT breast cancer cell lines that express high level of Snail or high level of Slug respectively. Specifically, we performed Snail ChIP seq in the mesenchymal pBl.3G cells, and Slug ChIP-seq in the epithelial pBl.1G cells.
Project description:Temporal expression profiling was utilized to define transcriptional regulatory pathways in vivo in a mouse muscle regeneration model. Potential downstream targets of MyoD were identified by temporal expression, promoter data base mining, and gel shift assays; Slug and calpain 6 were identified as novel MyoD targets. Slug, a member of the snail/slug family of zinc finger transcriptional repressors critical for mesoderm/ectoderm development, was further shown to be a downstream target by using promoter/reporter constructs and demonstration of defective muscle regeneration in Slug null mice. Keywords: other
Project description:Cancer stem cells (CSCs) are proposed to be responsible for metastatic dissemination and clinical relapse in a variety of cancers. Analogies between CSCs and normal tissue stem cells (SC) has led to the notion that CSCs often co-opt the normal SC program of their tissue-of-origin. The cell-biological program termed epithelial-mesenchymal transition (EMT) has been found to encourage entrance of normal and neoplastic mammary cells into the corresponding SC states. Using genetically engineered knock-in reporter mouse lines, we demonstrate that in the murine mammary lineage, the paralogous EMT-inducing transcription factors Snail and Slug, are selectively exploited by CSCs and normal SCs respectively. Slug, when expressed at physiological levels, only activates a partial EMT program and is dispensable in CSCs. In contrast, Snail drives a far more complete transition into the mesenchymal state and controls both tumor-initiation and metastatic dissemination. Consistent with their functional distinctions, Snail controls far more target genes than Slug, and their distinct functions are determined by their divergent N-terminal domains. Our findings underscore fundamental distinctions between the SC program operating in normal and neoplastic SCs, and hint for potential avenues of selective therapeutic elimination of breast CSCs.
Project description:Sustainable muscle regeneration necessitates proper maintenance of the quiescence-reversible SCs pool. Activation of p16Ink4a-associated senescence pathway during aging breaks muscle homeostasis and causes degenerative muscle disease by irreversibly dampening satellite cell (SC) self-renewal capacity. We performed microarrays analysis to compare the genome-wide gene expression profiles of wild-type and Slug-deficient SCs and identified distinct classes of up-regulated genes upon deletion of Slug gene.
Project description:Cyclin D1b is a splice variant of the cell cycle regulator Cyclin D1 and is known to harbor divergent and highly oncogenic functions in human disease. While Cyclin D1b is induced during disease progression in many cancer types, the mechanisms underlying Cyclin D1b function remain poorly understood. Herein, models of human disease were utilized to resolve the downstream pathways requisite for the pro-tumorigenic functions of Cyclin D1b. Specifically, it was shown that Cyclin D1b modulates the expression of a large transcriptional network that cooperates with AR signaling to enhance tumor cell growth and invasive potential. Notably, Cyclin D1b promoted AR-dependent activation of genes associated with metastatic phenotypes. Further exploration determined that transcriptional induction of SNAI2 (Slug) was essential for Cyclin D1b- mediated proliferative and invasive properties, implicating Slug as a critical driver of disease progression. Importantly, Cyclin D1b expression highly correlated with that of Slug in clinical samples of advanced disease. Further, in vivo analyses provided strong evidence that Slug enhances both tumor growth and homing to distal soft tissues. Collectively, these findings reveal the underpinning mechanisms behind the pro-tumorigenic functions of Cyclin D1b, and demonstrate that the convergence of the Cyclin D1b-AR and Slug pathways results in the activation of processes critical for the promotion of lethal tumor phenotypes. Analysis of transcriptomes under the control of individual D-type cyclin isoforms in the hormone dependent prostate cancer cell line LNCaP in the presence and absence of androgen. LNCaP cells cultured in charcoal dextran treated media were transduced with virus encoding Cyclin D1a, Cyclin D1b, or control GFP for 24 hours in biological triplicate. Cells were then stimulated with either 1nM DHT or 0.01% EtOH (vehicle control) for 16 hours and harvested for RNA