Evi1 is essential for proliferation of hematopoietic stem cells and implicated in the development of myeloid disorders. Particularly, high Evi1 expression defines one of the largest clusters in acute myeloid leukemia and is significantly associated with extremely poor prognosis. Improvement of the therapeutic outcome of leukemia with activated Evi1 is one of the most challenging issues. However, mechanistic basis of Evi1-mediated leukemogenesis has not been fully elucidated. Here we show that Evi1 directly represses PTEN transcription in the murine bone marrow, which leads to activation of AKT/mTOR signaling. In a murine bone marrow transplantation model, Evi1 leukemia showed remarkable sensitivity to an mTOR inihibitor rapamycin. Furthermore, we found that Evi1 binds to several polycomb group proteins and recruits polycomb repressive complexes for PTEN downregulation, which reveals a novel epigenetic mechanism of AKT/mTOR activation in leukemia. Expression analyses and chromatin immunoprecipitation assays using human samples indicate that our findings in mice models are recapitulated in human leukemic cells. Dependence of Evi1-expressing leukemic cells on AKT/mTOR signaling provides the first example of targeted therapeutic modalities that suppress the leukemogenic activity of Evi1. The PTEN/AKT/mTOR signaling pathway and the Evi1-polycomb interaction can be promising therapeutic targets for leukemia with activated Evi1.
Evi1 represses PTEN expression and activates PI3K/AKT/mTOR via interactions with polycomb proteins.
Specimen part, Treatment
View SamplesThere is a continuing need for driver strains to enable cell type-specific manipulation in the nervous system. Each cell type expresses a unique set of genes, and recapitulating expression of marker genes by BAC transgenesis or knock-in has generated useful transgenic mouse lines. However since genes are often expressed in many cell types, many of these lines have relatively broad expression patterns. We report an alternative transgenic approach capturing distal enhancers for more focused expression. We identified an enhancer trap probe often producing restricted reporter expression and developed efficient enhancer trap screening with the PiggyBac transposon. We established more than 200 lines and found many lines that label small subsets of neurons in brain substructures, including known and novel cell types. Images and other information about each line are available online (http://enhnacertrap.bio.brandeis.edu). Overall design: Examination of 6 cortical mouse neuronal cell types. 5 of which are in layer 6 in 3 different cortical regions.
A Mammalian enhancer trap resource for discovering and manipulating neuronal cell types.
Sex, Cell line, Subject
View SamplesGIST is considered to invariably arise through gain-of-function KIT or PDGFRA mutation of the interstitial cells of Cajal (ICC). However, the genetic basis of the malignant progression of GIST is poorly understood.
Distinct gene expression-defined classes of gastrointestinal stromal tumor.
Sex, Age
View SamplesThe purpose of the present study was to investigate the association of glutathione S-transferase P1 (GSTP1) expression with resistance to neoadjuvant paclitaxel followed by 5-fluorouracil/epirubicin/cyclophosphamide (P-FEC) in human breast cancers. The relationship of GSTP1 expression and GSTP1 promoter hypermethylation with intrinsic subtypes was also investigated. In this study, primary breast cancer patients (n = 123, stage II-III) treated with neoadjuvant P-FEC were analyzed. Tumor samples were obtained by vacuum-assisted core biopsy before P-FEC. GSTP1 expression was determined using immunohistochemistry, GSTP1 promoter methylation index (MI) using bisulfite methylation assay and intrinsic subtypes using DNA microarray. The pathological complete response (pCR) rate was significantly higher in GSTP1-negative tumors (80.0%) than GSTP1-positive tumors (30.6%) (P = 0.009) among estrogen receptor (ER)-negative tumors but not among ER-positive tumors (P = 0.267). Multivariate analysis showed that GSTP1 was the only predictive factor for pCR (P = 0.013) among ER-negative tumors. Luminal A, luminal B and HER2-enriched tumors showed a significantly lower GSTP1 positivity than basal-like tumors (P = 0.002, P < 0.001 and P = 0.009, respectively), while luminal A, luminal B and HER2-enriched tumors showed a higher GSTP1 MI than basal-like tumors (P = 0.076, P < 0.001 and P < 0.001, respectively). In conclusion, these results suggest the possibility that GSTP1 expression can predict pathological response to P-FEC in ER-negative tumors but not in ER-positive tumors. Additionally, GSTP1 promoter hypermethylation might be implicated more importantly in the pathogenesis of luminal A, luminal B and HER2-enriched tumors than basal-like tumors.
GSTP1 expression predicts poor pathological complete response to neoadjuvant chemotherapy in ER-negative breast cancer.
Age, Specimen part, Disease stage
View SamplesZinc-finger genes Fezf1 and Fezf2 encode transcriptional repressors. Fezf1 and Fezf2 are expressed in the early neural stem/progenitor cells and control neuronal differentiation in mouse dorsal telencephalon.
Zinc finger genes Fezf1 and Fezf2 control neuronal differentiation by repressing Hes5 expression in the forebrain.
Specimen part
View SamplesBackground. The in vivo distribution status and molecular signature of bone marrow mesenchymal stem cells (MSC) remain unknown, although ex vivo expanded MSC have been used in numerous studies.
Identification of mesenchymal stem cell (MSC)-transcription factors by microarray and knockdown analyses, and signature molecule-marked MSC in bone marrow by immunohistochemistry.
No sample metadata fields
View Samples7-days-old Arabidopsis seedlings of wildtype (Col-0) were treated with 1 M IAA for 15 minutes or 3 hours and gene expression of whole plant was analyzed using Affymetrix Gene 1.1 ST Array strips.
AtCAST3.0 update: a web-based tool for analysis of transcriptome data by searching similarities in gene expression profiles.
Age, Treatment, Time
View SamplesTranscriptional profiling of NKAES-derived NK cells after 7 days of culture compared to primary human NK cells and NK cells stimulated by low or high dose IL2 after 7 days of culture.
Expansion of highly cytotoxic human natural killer cells for cancer cell therapy.
Specimen part
View SamplesPerilipin A (PeriA) exclusively locates on adipocyte lipid droplets and is essential for lipid storage and lipolysis. Adipocyte specific overexpression of PeriA caused resistance to diet-induced obesity and resulted in improved insulin sensitivity. In order to better understand the biological basis for this observed phenotype we performed DNA microarray analysis on white adipose tissue (WAT) from PeriA transgenic (Tg) and control wildtype (WT) mice.
Perilipin overexpression in white adipose tissue induces a brown fat-like phenotype.
Sex, Specimen part
View SamplesAntibody-independent effector functions of B cells, such as antigen presentation and cytokine production, have been shown to play an important role in a variety of immune-mediated conditions such as autoimmune diseases, transplant rejection and graft-versus-host disease. Therapeutic strategies, which interfere with B cell activation could therefore be a useful addition to the current immunosuppressive armamentarium. CD40 is one of the strongest activation stimuli for B cells. The aim of this study was to characterise the gene expression changes that occurr after B cell activation via CD40.
Inhibition of protein geranylgeranylation specifically interferes with CD40-dependent B cell activation, resulting in a reduced capacity to induce T cell immunity.
Specimen part, Subject
View Samples