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:Cellular plasticity and transitional cellular states are crucial for tissue regeneration across multiple organs. In the pancreas, oncogenic Kras hijacks this program, acting on tissue-specific enhancers to prevent the resolution of acinar-to-ductal metaplasia (ADM) and lock regeneration into a pro-inflammatory state that progresses to cancer. Enhancer transcription, an early event during cellular state transitions, can generate stable enhancer-associated long noncoding RNAs (lncRNAs) positioned near key transcription factors and chromatin contact boundaries, often enriched for disease-associated variants. While enhancer-associated lncRNAs have been implicated in transcriptional regulation and genome organization, their role in pancreas regeneration and cancer initiation has remained unexplored. In this study, we identified epithelial long noncoding RNAs (lncRNAs) and their target genes in PDAC precursor lesion formation. We demonstrate that LINC00673, expressed from a Sox9-associated super-enhancer during pancreatic development, is reactivated in PDAC. Conditional deletion of LINC00673 in the murine pancreatic epithelium accelerates resolution of ADM and significantly impairs PDAC initiation. Furthermore, we highlight a previously unrecognized role of transcribed super-enhancers in facilitating long-range gene regulation and genome organization during pancreatic cancer initiation. Our study identifies a critical function of LINC00673 in regulating both cell-autonomous and non-cell-autonomous processes during pancreas regeneration and Kras-driven cancer initiation. These findings reveal a novel regulatory layer linking developmental enhancer activity to pancreatic disease progression and highlight new therapeutic opportunities targeting regenerative programs at the earliest stages of neoplastic transformation.
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.