Basal-like and luminal breast tumors have distinct clinical behavior and molecular profiles, yet the underlying mechanisms are poorly defined. To interrogate processes that determine these distinct phenotypes and their inheritance pattern, we generated somatic cell fusions and performed integrated genetic and epigenetic (DNA methylation and chromatin) profiling. We found that the basal-like trait is generally dominant and it is largely defined by epigenetic repression of luminal transcription factors. Definition of super-enhancers highlighted a core program common in luminal cells but high degree of heterogeneity in basal-like breast cancers that correlates with clinical outcome. We also found that protein extracts of basal-like cells is sufficient to induce luminal-to-basal phenotypic switch implying a trigger of basal-like autoregulatory circuits. We determined that KDM6A might be required for luminal-basal fusions, and identified EN1, TBX18, and TCF4 as candidate transcriptional regulators of luminal-to-basal switch. Our findings highlight the remarkable epigenetic plasticity of breast cancer cells. Overall design: RNA-Seq in breast cancer cell-lines
Somatic Cell Fusions Reveal Extensive Heterogeneity in Basal-like Breast Cancer.
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Autophagy maintains the metabolism and function of young and old stem cells.
Specimen part
View SamplesAutophagy is critical for protecting HSCs from metabolic stress. Here, we used a genetic approach to inactivate autophagy in adult HSCs by deleting the Atg12 gene. We show that loss of autophagy causes accumulation of mitochondria and an oxidative phosphorylation (OXPHOS)-activated metabolic state, which drives accelerated myeloid differentiation likely through epigenetic deregulations rather than transcriptional changes, and impairs HSC self-renewal activity and regenerative potential.
Autophagy maintains the metabolism and function of young and old stem cells.
Specimen part
View SamplesWe identified that knocking down Map4k4 in endothelial cells affected genes associated with the cell cycle, mitosis, and inflammatory genes.
Endothelial Mitogen-Activated Protein Kinase Kinase Kinase Kinase 4 Is Critical for Lymphatic Vascular Development and Function.
Specimen part
View SamplesMultipotent stromal cells (MSC) and their osteoblastic lineage cell (OBC) derivatives are part of the bone marrow (BM) niche and contribute to hematopoietic stem cell (HSC) maintenance. During myeloproliferative neoplasm (MPN) development, MSCs are stimulated to overproduce functtionally altered OBCs, which accumulate in the BM cavity as myelofibrotic cells. These MPN-expanded OBCs, in turn, impair the maintenance of normal HSCs but not of leukemic stem cells.
Myeloproliferative neoplasia remodels the endosteal bone marrow niche into a self-reinforcing leukemic niche.
Specimen part, Time
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MEF2C protects bone marrow B-lymphoid progenitors during stress haematopoiesis.
Age, Specimen part
View SamplesGene expression of mice bone marrow pre-B cells from both control and Vav-Cre Mef2cfl/fl mice (9 months old)
MEF2C protects bone marrow B-lymphoid progenitors during stress haematopoiesis.
Age, Specimen part
View SamplesGene expression of mice bone marrow pro-B cells from both control and Vav-Cre Mef2cfl/fl mice (9 months old)
MEF2C protects bone marrow B-lymphoid progenitors during stress haematopoiesis.
Age, Specimen part
View SamplesIn a screen for upregulated adipocyte genes in insulin resistant versus insulin sensitive subjects matched for BMI, we identified the type II transmembrane protein tenomodulin (TNMD), previously implicated in glucose tolerance in gene association studies. TNMD expression was greatly increased in human preadipocytes during differentiation, while silencing TNMD blocked adipogenic gene induction and adipogenesis.
Tenomodulin promotes human adipocyte differentiation and beneficial visceral adipose tissue expansion.
Specimen part
View SamplesDietary polyunsaturated fatty acids (PUFA) act as potent natural hypolipidemics and are linked to many health benefits in humans and in animal models. Mice fed long-term a high fat diet, in which medium-chain alpha linoleic acid (ALA) was partially replaced by long-chain docosahexaenoic (DHA) and eicosapentaenoic (EPA) fatty acids, showed reduced accumulation of body fat and prevention of insulin resistance, besides increased mitochondrial beta-oxidation in white adipose tissue and decreased plasma lipids. ALA, EPA and DHA all belong to PUFA of n-3 series. The intestine is a gatekeeper organ for ingested lipids. To examine the potential contribution of the intestine in the beneficial effects of EPA and DHA, this study assessed gene expression changes using whole genome microarray analysis on small intestinal scrapings. The main biological process affected was lipid metabolism. Fatty acid uptake, peroxisomal and mitochondrial beta-oxidation, and omega-oxidation of fatty acids were all increased. Quantitative real time PCR and intestinal fatty acid oxidation measurements ([14C(U)]-palmitate) confirmed significant gene expression differences in a dose-dependent manner. Furthermore, no major changes in the expression of lipid metabolism genes were observed in colonic scrapings. In conclusion, we show that marine n-3 fatty acids regulate small intestinal gene expression patterns. Since this organ contributes significantly to whole organism energy use, this adaptation of the small intestine may contribute to the complex and observed beneficial physiological effects of these natural compounds under conditions that will normally lead to development of obesity and diabetes.
Induction of lipid oxidation by polyunsaturated fatty acids of marine origin in small intestine of mice fed a high-fat diet.
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