Proceedings of the National Academy of Sciences of the United States of America 20050224 11
The AML1-ETO fusion protein, generated by the t(8;21) in acute myeloid leukemia (AML), exerts dominant-negative functions and a variety of gains of function, including a positive effect on the growth of primary human CD34+ hematopoietic stem/progenitor cells. We now show that AML1-ETO expression up-regulates the level of TRKA mRNA and protein in these cells and that AML1-ETO-expressing CD34+ hematopoietic cells grown in the presence of five early-acting hematopoietic cytokines further proliferat ...[more]
Project description:Compare the gene expression profile among human CD34+ cord blood cells infected with MIGR1, MIGR1-AML1-ETO or MIGR1-AML1-ETO∆NHR1 AML1-ETO promotes the self-renewal of human hematopoietic stem/progenitor cells (HSPCs). We found deletion of NHR1 domain abrogates AML1-ETO induced expasion of HSPCs. GFP+CD34+ human cord blood cells were sorted by FACS 72 hours after the infection for RNA extraction and hybridyzation for Affymetrix microarrays.
Project description:To generate normal control microarrays, RNA was isolated from 3 samples of cord blood derived-CD34+ cells activated with cytokines. We used Affymetrix expression profiles of CD34+ cells isolated from 3 normal donors (for LV-GFP and random sites) and activated in culture in the same conditions used for lentiviral transduction as control.
Project description:Tumors contain a fraction of cancer stem cells that maintain the propagation of the disease. The CD34CD38_ cells, isolated from acute myeloid leukemia (AML), were shown to be enriched leukemic stem cells (LSC). We isolated the CD34CD38_ cell fraction from AML and compared their gene expression profiles to the CD34CD38 cell fraction, using microarrays. We found 409 genes that were at least twofold over- or underexpressed between the two cell populations. These include underexpression of DNA repair, signal transduction and cell cycle genes, consistent with the relative quiescence of stem cells, and chromosomal aberrations and mutations of leukemic cells. Comparison of the LSC expression data to that of normal hematopoietic stem cells (HSC) revealed that 34% of the modulated genes are shared by both LSC and HSC, supporting the suggestion that the LSC originated within the HSC progenitors. We focused on the Notch pathway since Jagged-2, a Notch ligand was found to be overexpressed in the LSC samples. We show that DAPT, an inhibitor of gamma-secretase, a protease that is involved in Jagged and Notch signaling, inhibits LSC growth in colony formation assays. Identification of additional genes that regulate LSC self-renewal may provide new targets for therapy. Microarrays were used to compare the gene expression patterns between AML CD34+CD38- cells and AML CD34+CD38+
Project description:Signaling through the AKT and ERK pathways controls cell proliferation. However, the integrated regulation of this multistep process, involving signal processing, cell growth and cell-cycle progression, is poorly understood. Here we study different murine hematopoietic cell types, in which AKT and ERK signaling is triggered by erythropoietin (Epo). Although these cell types share the molecular network topology for pro-proliferative Epo signaling, they exhibit distinct proliferative responses. Iterating quantitative experiments and mathematical modeling, we identify two molecular sources for cell-type-specific proliferation. First, cell-type-specific protein abundance patterns cause differential signal flow along the AKT and ERK pathways. Second, downstream regulators of both pathways have differential effects on proliferation, suggesting that protein synthesis is rate-limiting for faster-cycling cells while slower cell-cycles are controlled at the G1-S progression. The integrated mathematical model of Epo-driven proliferation explains cell-type-specific effects of targeted AKT and ERK inhibitors and faithfully predicts based on the protein abundance anti-proliferative effects of inhibitors in primary human erythroid progenitor cells. Our findings suggest that the effectiveness of targeted cancer therapy might become predictable from protein abundance patterns.
Project description:We derived B-lineage cells by in vitro culture of neonatal cord blood CD34+ cells on MS-5 stromal cells with recombinant IL-7. These cultures yielded CD19+CD127+ and CD19+CD127- cell populations. We performed gene expression profiling on these populations and compared these with each other and with published expression profiles of freshly isolated BM precursor B-cell subsets (E-MEXP-384). These analyses yielded new insights into their different functionality and developmental stage.<br><br>A file containing statistical analysis of the normalized data is included in the file named E-MEXP-2878.additional.zip on the FTP site for this experiment.
Project description:In order to elucidate the molecular mechanism giving rise to the rare In(Lu) type of Lu(a-b-) blood group phenotype we compared the transcriptome of normal and In(Lu) erythroblasts at different stages of maturation. Many erythroid-specific genes had reduced transcript levels suggesting the phenotype resulted from a transcription factor abnormality. A search for mutations in erythroid transcription factors revealed mutations in the promoter or coding sequence of EKLF in 21 of 24 individuals with the In(Lu) phenotype. In all cases the mutant EKLF allele occurred in the presence of a normal EKLF allele. Individuals with the In(Lu) phenotype have no reported pathology indicating that one functional EKLF allele is sufficient to sustain human erythropoiesis. These data provide the first description of inactivating mutations in human EKLF and the first demonstration of a blood group phenotype resulting from mutations in a transcription factor. Experiment Overall Design: Time course study looking at changes in gene expression during erythropoiesis in two cell types: cultured erythroblasts (days 4, 6 and 11) from normal blood donors and from those with the rare blood group In(Lu) phenotype. There are 20 samples in total (10 for each cell type). For each cell type there are 2 samples at day 4 (1 biological replicate, 2 technical replicates, and 4 samples at each of days 6 and 11 (2 biological replicates, 2 technical replicates).
Project description:Here we compare the transcriptional profile of HMB-PP-stimulated versus OKT-3 stimulated human peripheral blood gamma-delta T cells. We show that HMB-PP faithfully reproduces the transcriptional events associated with bona fide activation through the T cell receptor (TCR).
Project description:We used microarrays to analyze the gene expression profile of CD34+CD45RA+CD7+, CD34+CD45RA+CD10+CD19- and CD34+CD45+CD7-CD10-CD19- HPCs isolated from umbilical cord blood CD34+CD45RA+CD7+(CD10-) and CD34+CD45RA+CD10+(CD7-CD19-) HPCs correspond respectively to prothymocytes and early pre-proB precursors. CD34+CD45RA+CD7-CD10-CD19- HPCs correspond to lympho-granulo-macrophagic precursors The corresponding populations were sorted from total CD34+ HPCs isolated from 2 or 3 individual donors
Project description:Purpose: This study was conducted to identify novel genes with importance to the biology of adult acute myelogenous leukemia (AML). Conclusions: NF1 null states are present in 7/95=7% of adult AML and delineate a disease subset that could be preferentially targeted by Ras or mTOR-directed therapeutics. Experimental design: We analyzed DNA from highly purified AML blasts and paired buccal cells from 95 patients for recurrent genomic microdeletions using ultra-high density Affymetrix SNP 6.0 array-based genomic profiling. 006, 096 and 136 normal Samples have been excluded from study.