This SuperSeries is composed of the SubSeries listed below.
Pbx1 regulates self-renewal of long-term hematopoietic stem cells by maintaining their quiescence.
Age, Specimen part
View SamplesSelf-renewal is a defining characteristic of stem cells, however the molecular pathways underlying its regulation are poorly understood. Here we demonstrate that conditional inactivation of the Pbx1 proto-oncogene in the hematopoietic compartment results in a progressive loss of long-term hematopoietic stem cells (LT-HSCs) that is associated with concomitant reduction in their quiescence, leading to a defect in the maintenance of self-renewal as assessed by serial transplantation. Transcriptional profiling revealed that multiple stem cell maintenance factors are perturbed in Pbx1-deficient LT-HSCs, which prematurely express a large subset of genes, including cell cycle regulators, normally expressed in non-self-renewing multipotent progenitors. A significant proportion of Pbx1-dependent genes are associated with the Tgf-b pathway, which serves a major role in maintaining HSC quiescence. Pbx1-deficient LT-HSCs are unable to up-regulate the cyclin dependent kinase inhibitor p57 in response to Tgf-b, providing a mechanism through which Pbx1 maintenance of stem cell self-renewal is achieved.
Pbx1 regulates self-renewal of long-term hematopoietic stem cells by maintaining their quiescence.
Age, Specimen part
View SamplesSelf-renewal is a defining characteristic of stem cells, however the molecular pathways underlying its regulation are poorly understood. Here we demonstrate that conditional inactivation of the Pbx1 proto-oncogene in the hematopoietic compartment results in a progressive loss of long-term hematopoietic stem cells (LT-HSCs) that is associated with concomitant reduction in their quiescence, leading to a defect in the maintenance of self-renewal as assessed by serial transplantation. Transcriptional profiling revealed that multiple stem cell maintenance factors are perturbed in Pbx1-deficient LT-HSCs, which prematurely express a large subset of genes, including cell cycle regulators, normally expressed in non-self-renewing multipotent progenitors.
Pbx1 regulates self-renewal of long-term hematopoietic stem cells by maintaining their quiescence.
Age, Specimen part
View SamplesThe capacity of the hematopoietic system to promptly respond to peripheral demands relies on adequate pools of progenitors able to transiently proliferate and differentiate in a regulated manner. However, little is known about factors that may restrain progenitor maturation to maintain their reservoirs. In addition to a profound defect in hematopoietic stem cell (HSC) self-renewal, conditional knockout mice for the Pbx1 proto-oncogene have a significant reduction in lineage-restricted progenitors, including common myeloid progenitors (CMPs) and, to a lesser extent, granulocyte-monocyte progenitors (GMPs).
Pbx1 restrains myeloid maturation while preserving lymphoid potential in hematopoietic progenitors.
Age, Specimen part
View SamplesHuman leukemia cell line RS4.11 was treated with GSK-3 inhibitor SB216763 for 20 hours. Gene expression profiling was performed to analyze genes affected by GSK-3 inhibition.
GSK-3 promotes conditional association of CREB and its coactivators with MEIS1 to facilitate HOX-mediated transcription and oncogenesis.
Treatment
View SamplesDifferences in the inherent properties of undifferentiated fat cell progenitors may contribute to the biological specificity of the abdominal subcutaneous (Sc) and visceral omental (V) fat depots. In this study, the biological characteristics of three distinct subpopulations of adipose tissue-derived stem cells (ASC), i.e. ASCSVF, ASCBottom and ASCCeiling isolated from Sc and V adipose tissue biopsies of non-obese subjects, were investigated. Genome-wide differential gene expression analysis followed by quantitative RT-PCR and analysis of cytokines in the ASC-derived conditioned medium were performed. By analysis of 28,869 annotated genes, 1,019 genes resulted differentially expressed between Sc-ASC and V-ASC. Within the Sc-ASC and V-ASC populations, 546 and 1,222, respectively, were the genes differentially expressed among ASCSVF, ASCBottom and ASCCeiling. A far more striking difference was found when the hierarchical clusters analysis was performed comparing each Sc-ASC with its own homologous V-ASC subset. mRNA levels of HoxA5, Tbx15, PI16, PITPNC1, FABP5, IL-6, IL-8, MCP-1, VEGF, MMP3, TFPI2, and ANXA10 were significantly different between Sc-ASC and V-ASC. Of the 27 cytokines measured, 14 (IL-2, IL-4, IL-5 IL-7, IL-9, IL-10, IL12, IL13, MIP1-, MIP1-, PDGF-, FGFbasic, GM-CSF, IP-10) were not released, whereas 13 were expressed (IL-1beta, IL-1ra, IL-15, IL-17, G-CSF, IFN, RANTES, TNF-, Eotaxin, IL-8, MCP-1, VEGF, IL-6), and of these, MCP-1, Eotaxin, IL-1ra, FGFbasic, IL-6, IL-8, G-CSF, and VEGF were significantly different among ASCSVF, ASCCeiling and ASCBottom of the two adipose tissue depots. These results demonstrate the existence of genetically and functionally heterogeneous fat-derived ASC populations, which may add to the complexity and specificity of Sc and V adipose tissue in humans.
Differences in gene expression and cytokine release profiles highlight the heterogeneity of distinct subsets of adipose tissue-derived stem cells in the subcutaneous and visceral adipose tissue in humans.
Specimen part
View SamplesUsing global gene expression and proteomic analyses, we identified a molecular signature in human embryonic and induced pluripotent stem cells that suggested a central regulatory role for RNA splicing in self-renewal. Through genetic and biochemical approaches, we established reciprocal functional links between the master regulatory factor OCT4 and SFRS2, a member of the serine/arginine-rich family of splicing factors. SFRS2 regulates expression of two isoforms of the methyl-CpG-binding protein MBD2 that play opposing roles in human ESC and during the reprogramming of fibroblasts. Both the MBD2a isoform expressed in fibroblasts and the MBD2c isoform found in pluripotent cells bind OCT4 and NANOG promoters in human ESC, but only MBD2a interacts with NuRD chromatin remodeling factors. Members of the miR-301 and miR-302 families provide additional regulation by targeting SFRS2 and the somatic specific MBD2a isoform. These data are consistent with a model in which OCT4, SFRS2, and MBD2 participate in a positive feedback loop to regulate proteome diversity in support of self-renewal in pluripotent cells.
Alternative splicing of MBD2 supports self-renewal in human pluripotent stem cells.
Specimen part
View SamplesThe CHER-LOB randomized phase II study showed that the combination of lapatinib and trastuzumab plus chemotherapy increases the pathologic complete remission (pCR) rate as compared to chemotherapy plus either trastuzumab or lapatinib. An extensive biomarker programme was prospectively planned to identify potential predictors of sensitivity to different treatments and evaluate treatment effect on tumor biomarkers.
Prospective Biomarker Analysis of the Randomized CHER-LOB Study Evaluating the Dual Anti-HER2 Treatment With Trastuzumab and Lapatinib Plus Chemotherapy as Neoadjuvant Therapy for HER2-Positive Breast Cancer.
Specimen part, Disease, Disease stage
View SamplesIn acute myeloid leukemia, chemotherapy resistance remains prevalent and poorly understood. Using functional proteomics of patient AML specimens, we identified MEF2C S222 phosphorylation as a specific marker of primary chemoresistance. We found that transgenic Mef2cS222A/S222A mice engineered to block MEF2C phosphorylation exhibited normal hematopoiesis, but were resistant to leukemogenesis induced by MLL-AF9. MEF2C phosphorylation was required for leukemia stem cell maintenance, induced by MARK kinases in cells, and blocked by selective MARK inhibitor MRT199665, which caused apoptosis of MEF2C-activated human AML cell lines and primary patient specimens, but not those lacking MEF2C. These findings identify signaling-dependent dysregulation of transcription factor control as a determinant of therapy response in AML, with immediate potential for improved diagnosis and therapy for this disease. Overall design: RNA-sequencing of human leukemia cell line with induction of wildtype or mutant MEF2C.
MEF2C Phosphorylation Is Required for Chemotherapy Resistance in Acute Myeloid Leukemia.
Specimen part, Cell line, Treatment, Subject
View SamplesIn acute myeloid leukemia, chemotherapy resistance remains prevalent and poorly understood. Using functional proteomics of patient AML specimens, we identified MEF2C S222 phosphorylation as a specific marker of primary chemoresistance. We found that transgenic Mef2cS222A/S222A mice engineered to block MEF2C phosphorylation exhibited normal hematopoiesis, but were resistant to leukemogenesis induced by MLL-AF9. MEF2C phosphorylation was required for leukemia stem cell maintenance, induced by MARK kinases in cells, and blocked by selective MARK inhibitor MRT199665, which caused apoptosis of MEF2C-activated human AML cell lines and primary patient specimens, but not those lacking MEF2C. These findings identify signaling-dependent dysregulation of transcription factor control as a determinant of therapy response in AML, with immediate potential for improved diagnosis and therapy for this disease. Overall design: RNA-sequencing of human leukemia cell line with treatment of MARK inhibitor MRT199665.
MEF2C Phosphorylation Is Required for Chemotherapy Resistance in Acute Myeloid Leukemia.
Specimen part, Cell line, Treatment, Subject
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