Forced expression of Bmi1 accelerated the self-renewal of hepatic stem/progenitor cells and eventually induced their transformation in an in vivo transplant model. The Ink4a/Arf locus, which encodes a cyclin-dependent kinase inhibitor, p16Ink4a, and a tumor suppressor, p19Arf, is a pivotal target of Bmi1. Therefore, it would be of importance to understand the contribution of the Ink4a/Arf locus to Bmi1 oncogenic functions in cancer and search for as-yet-unknown Bmi1 target genes other than Ink4a/Arf. We used microarrays to explore novel candidate downstream targets for Bmi1 in hepatic stem/progenitor cells
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Specimen part
View SamplesBmi1 is a component of polycomb repressive complex 1 and its role in the inheritance of the stemness of adult somatic stem cells has been well characterized. Bmi1 maintains the self-renewal capacity of adult stem cells, at least partially, by repressing the Ink4a/Arf locus that encodes a cyclin-dependent kinase inhibitor, p16Ink4a, and a tumor suppressor, p19Arf 14. Deletion of both Ink4a and Arf in Bmi1-deficient mice substantially restored the defective self-renewal capacity of HSCs and neural stem cells.
Poised lineage specification in multipotential hematopoietic stem and progenitor cells by the polycomb protein Bmi1.
Specimen part
View SamplesBmi1 is a component of polycomb repressive complex 1 and its role in the inheritance of the stemness of adult somatic stem cells has been well characterized. Bmi1 maintains the self-renewal capacity of adult stem cells, at least partially, by repressing the Ink4a/Arf locus that encodes a cyclin-dependent kinase inhibitor, p16Ink4a, and a tumor suppressor, p19Arf 14. Deletion of both Ink4a and Arf in Bmi1-deficient mice substantially restored the defective self-renewal capacity of HSCs and neural stem cells.
Lethal myelofibrosis induced by Bmi1-deficient hematopoietic cells unveils a tumor suppressor function of the polycomb group genes.
Specimen part
View SamplesFus is the gene for a member of the FET family of RNA-binding proteins often involved in chromosomal translocations to generate oncogenic fusion genes in human cancers. Fus participates in multiple cellular functions, including RNA processing and transport, transcriptional regulation, and genome integrity. We uncovered its critical role in the maintenance of hematopoietic stem cells (HSCs). Fus-/- fetal livers developed normally except for a mild reduction in numbers of colony-forming cells compared to the wild type. The proliferation and differentiation of Fus-/- hematopoietic progenitors were normal in vitro. However, the number of colony-forming cells present in long-term cocultures of Fus-/- hematopoietic progenitors and stromal cells was significantly reduced. Fus-/- HSCs had an impaired long-term repopulating capacity and failed to repopulate in tertiary recipient mice. Fus-/- HSCs were highly susceptible to radiation both in vitro and in vivo and showed retardation of radiation-induced DNA damage repair. These findings define Fus as a novel regulator of HSCs and implicate it in stress-resistance and maintenance of the genomic integrity of HSCs. Therefore, it would be of importance to analyze the gene expression profiles of Fus-knockout hematopoietic stem/progenitor cells to understand its role in HSCs.
FET family proto-oncogene Fus contributes to self-renewal of hematopoietic stem cells.
Specimen part
View SamplesThe polycomb group (PcG) proteins function in gene silencing through histone modifications. They form chromatin-associated multiprotein complexes, termed polycomb repressive complex (PRC) 1 and PRC2. These two complexes work in a coordinated manner in the maintenance of cellular memories through transcriptional repression of target genes. EZH2 is a catalytic component of PRC2 and trimethylates histone H3 at lysine 27 to transcriptionally repress the target genes. PcG proteins have been characterized as general regulators of stem cells, but recent works also unveiled their critical roles in cancer.
Ezh2 augments leukemogenicity by reinforcing differentiation blockage in acute myeloid leukemia.
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View SamplesComparison between livers of FLS mice and livers of DS (DD shionogi) mice
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Specimen part
View SamplesTo identify a novel target for the treatment of heart failure, we examined gene expression in the failing heart. Among the genes analyzed, 12/15 lipoxygenase (12/15-LOX) was markedly up-regulated in heart failure. To determine whether increased expression of 12/15-LOX causes heart failure, we established transgenic mice that overexpressed 12/15-LOX in cardiomyocytes. Echocardiography showed that 12/15-LOX transgenic mice developed systolic dysfunction. Cardiac fibrosis increased in 12/15-LOX transgenic mice with advancing age, and was associated with the infiltration of macrophages. Consistent with these observations, cardiac expression of monocyte chemoattractant protein-1 (Mcp-1) was up-regulated in 12/15-LOX transgenic mice compared with wild-type mice. Treatment with 12-hydroxy-eicosatetraenotic acid, a major metabolite of 12/15-LOX, increased MCP-1 expression in cardiac fibroblasts and endothelial cells, but not in cardiomyocytes. Inhibition of Mcp-1 reduced the infiltration of macrophages into the myocardium and prevented both systolic dysfunction and cardiac fibrosis in 12/15-LOX transgenic mice. Likewise, disruption of 12/15-LOX significantly reduced cardiac Mcp-1 expression and macrophage infiltration, thereby improving systolic dysfunction induced by chronic pressure overload. Our results suggest that cardiac 12/15-LOX is involved in the development of heart failure and that inhibition of 12/15-LOX could be a novel treatment for this condition.
Cardiac 12/15 lipoxygenase-induced inflammation is involved in heart failure.
Sex, Age
View SamplesGene expression profiles of LT-HSCs (Lin-Sca1+cKit+Flk2-CD34-), ST-HSCs (Lin-Sca1+cKit+Flk2-CD34+), MPP (Lin-Sca1+cKit+Flk2+CD34+) and LK (Lin-Sca1-cKit+).
No associated publication
Specimen part, Cell line
View SamplesSetdb1, an H3K9 histone methyltransferase, plays an essential role in silencing of endogenous retroviral elements (ERVs) in early embryo and embryonic stem cells (ESCs). However, its role in somatic stem cells remains unclear. We show that deletion of Setdb1 causes rapid depletion of hematopoietic stem and progenitor cells (HSPCs) and leukemic stem cells. Contrary to ESCs, ERVs were largely repressed and stem cell gene signature was maintained in Setdb1-deficient HSPCs. Instead, a list of non-hematopoietic genes were ectopically activated following reduction in H3K9me3 levels, including epithelial cell adhesion molecule (EpCAM) and Fructose-1,6-bisphosphatase (Fbp2), a muscle-specific gluconeogenesis enzyme gene, in HSPCs, resulting in egression of HSPCs from the bone marrow and compromised cell growth and energy production. Our findings demonstrate that Setdb1 little contributes to the silencing of ERVs in HSPCs but is critical for restricting ectopic activation of non-hematopoietic genes detrimental to HSPCs.
No associated publication
Specimen part, Cell line
View SamplesNon-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations have shown a dramatic response to EGFR inhibitors (EGFR-TKI). EGFR T790M mutation and MET amplification have been recognized as major mechanisms of acquired resistance to EGFR-TKI. Therefore, MET inhibitors have recently been used in NSCLC patients in clinical trials. In this study, we tried to identify the mechanism of acquired resistance to MET inhibitor. We analyzed the antitumor effects of two MET inhibitors, PHA-665752 and crizotinib, in 10 NSCLC cell lines. EBC1 cells with MET amplification were the only cells that were sensitive to both MET inhibitors. We established PHA-665752-resistant EBC1 cells, namely EBC1-R cells. EBC1-R cells showed overexpression of ATP-binding cassette sub-family B member 1 (ABCB1) as well as phosphorylation of MET. EBC1-R cells grew as cell spheres that exhibited cancer stem cell-like (CSC) properties and epithelial mesenchymal transition (EMT). The levels of two miRNAs, miR-374a and miR-138 which targeted ABCB1, were decreased in EBC1-R cells. ABCB1 siRNA and ABCB1 inhibitor elacridar could reduce sphere numbers and suppress EMT. Elacridar could also reverse the resistance to PHA-665752 in EBC1-R cells. Our study demonstrated that ABCB1 overexpression which was associated with CSC properties and EMT was involved in the acquired resistance to MET inhibitor. Inhibition of ABCB1 might be a novel therapeutic strategy for NSCLC patients with acquired resistance to MET inhibitor.
Inhibition of ABCB1 Overcomes Cancer Stem Cell-like Properties and Acquired Resistance to MET Inhibitors in Non-Small Cell Lung Cancer.
Cell line
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