Relapse, associated with therapy resistance, is a major clinical problem in acute myeloid leukemia (AML), yet little is known about the underlying molecular mechanisms. Using genome wide gene expression profiling on 11 paired samples from diagnosis and relapse, we show that the expression of a substantial number of genes was altered in a highly consistent manner between these disease stages. Furthermore, the relapse associated gene expression profile was significantly enriched for leukemia stem cell (LSC) genes, indicating that recurring AML is characterized by increased stemness, and supporting the concept that it is due to the outgrowth of chemotherapy resistant LSCs.
A gene expression profile associated with relapse of cytogenetically normal acute myeloid leukemia is enriched for leukemia stem cell genes.
Sex, Age
View SamplesBackground: The transcription factor EVI1 regulates cellular proliferation, differentiation, and apoptosis, and contributes to an aggressive course of disease in myeloid leukemias and other malignancies. Notwithstanding, knowledge about the target genes mediating its biological and pathological functions remains limited. We therefore aimed to identify and characterize novel EVI1 target genes in human myeloid cells. Methods: U937T_EVI1, a previously established human myeloid cell line expressing EVI1 in a tetracycline regulable manner, was subjected to genome wide gene expression microarray analysis. qRT-PCR was used to confirm the regulation of MS4A3 by EVI1. Reporter constructs containing various parts of the MS4A3 upstream region were employed in luciferase assays, and direct binding of EVI1 to the MS4A3 promoter was investigated by chromatin immunoprecipitation. U937 derivative cell lines experimentally expressing EVI1 and/or MS4A3 were generated by retroviral transduction, and tested for their tumorigenicity by subcutaneous injection into severe combined immunodeficient mice. Experimental results were tested for statistical significance using ANOVA and Student's t-test (two-tailed). Results: Gene expression microarray analysis identified 27 unique genes that were up-regulated and 29 that were down-regulated in response to EVI1 induction in the human myeloid cell line, U937. The most strongly repressed gene was membrane-spanning-4-domains subfamily-A member-3 (MS4A3), and its down-regulation by EVI1 was confirmed by qRT-PCR in additional, independent experimental model systems. Reporter gene assays and chromatin immunoprecipitation showed that EVI1 regulated MS4A3 via direct binding to a promoter proximal region. Experimental re-expression of MS4A3 in an EVI1 overexpressing cell line counteracted the tumor promoting effect of EVI1 in a murine xenograft model. Conclusions: Our data reveal MS4A3 as a novel direct target of EVI1 in human myeloid cells, and show that its repression plays a role in EVI1 mediated tumor aggressiveness.
EVI1 promotes tumor growth via transcriptional repression of MS4A3.
Cell line, Time
View SamplesOverexpression of ecotropic viral integration site 1 (EVI1) is associated with aggressive disease in acute myeloid leukemia (AML). Despite of its clinical importance, little is known about the mechanism through which EVI1 confers resistance to antileukemic drugs. Here, we show that a human myeloid cell line constitutively overexpressing EVI1 after infection with a retroviral vector (U937_EVI1) was partially resistant to etoposide and daunorubicin as compared to empty vector infected control cells (U937_vec). Similarly, inducible expression of EVI1 in HL-60 cells decreased their sensitivity to daunorubicin. Gene expression microarray analyses of U937_EVI1 and U937_vec cells cultured in the absence or presence of etoposide showed that 77 and 419 genes were regulated by EVI1 and etoposide, respectively. Notably, mRNA levels of 26 of these genes were altered by both stimuli, indicating that EVI1 regulated genes were strongly enriched among etoposide regulated genes and vice versa. One of the genes that were induced by both EVI1 and etoposide was CDKN1A/p21/WAF, which in addition to its function as a cell cycle regulator plays an important role in conferring chemotherapy resistance in various tumor types. Indeed, overexpression of CDKN1A in U937 cells mimicked the phenotype of EVI1 overexpression, similarly conferring partial resistance to antileukemic drugs.
EVI1 inhibits apoptosis induced by antileukemic drugs via upregulation of CDKN1A/p21/WAF in human myeloid cells.
Cell line, Treatment
View SamplesTarget specific short single-stranded DNA (ssDNA) molecules, called aptamers, are auspicious ligands for numerous in vivo applications. However, aptamers are synthetic molecules, which might be recognized by the immune cells in vivo and induce an activation of the innate immune system. Thus, immune activation potential of synthetic ssDNA oligonucleotides (ODNs) was determined using a well established closed-loop circulation model. Fresh human blood was incubated at 37C for 2 or 4 hours with ssDNA ODNs (SB_ODN) or CpG ODN as positive control. Transcriptional changes were determined by microarray analyses. Blood samples containing SB_ODN demonstrated after 4 hours a significant regulation of 295 transcripts. Amongst others, CCL8, CXCL10, CCL7 and CXCL11 were highest regulated genes. Gene Ontology terms and KEGG pathway analyses exhibited that the differentially expressed genes belong to the transcripts that are regulated during an immune and inflammatory response, and were overrepresented in TLR signaling pathway. This study shows for the first time the potential of aptamers to activate immune system after systemic application into the human blood. Thus, we highly recommend performing of these preclinical tests with potential aptamer-based therapeutics.
Potential capacity of aptamers to trigger immune activation in human blood.
Sex, Specimen part, Treatment, Subject, Time
View SamplesWe have performed whole genome expression arrays covering over 47000 transcripts comparing the transcriptional profile of NKp80+ to NKp80- CD8+ CCR7- alpha beta T cells. A highly similar global gene expression profile was observed between both memory phenotype T cell subsets. Interestingly, the majority of differentially expressed genes are immune-associated. NKp80+ cells contained markedly increased levels of transcripts encoding for MHC class I and II molecules and for numerous members of the KIR family. Also other NK-related transcripts were more abundantly expressed in the NKp80+ subset. With regards to cytokines, chemokines and their receptors, transcripts important for homeostasis and proliferation are expressed differently. Also transcripts encoding for adhesion molecules are present at different levels in both T cell subsets. Further cytotoxic effector molecules are expressed differently.
NKp80 defines and stimulates a reactive subset of CD8 T cells.
Sex, Specimen part
View SamplesThis study was performed to identify gene expression differences in not otherwise specified soft tissue sarcomas (NOS, malignant fibrous histiocytomas) and correlate them to histological findings and the clinical course. RNA was isolated and differential gene expression was analysed by the microarray technique.
Malignant fibrous histiocytoma--pleomorphic sarcoma, NOS gene expression, histology, and clinical course. A pilot study.
Sex
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Intra-ophthalmic artery chemotherapy triggers vascular toxicity through endothelial cell inflammation and leukostasis.
Specimen part, Treatment
View SamplesSuper-selective intra-ophthalmic artery chemotherapy (SSIOAC) is an organ-specific drug-delivery strategy to treat retinoblastoma, the most common primary ocular malignancy in children. Unfortunately, recent clinical reports associate adverse vascular toxicities with SSIOAC using melphalan, the most commonly used chemotherapeutic. To explore the reason for the unexpected vascular toxicities, we have developed in vitro studies with human retinal endothelial cells to test the effects of the chemotherapeutics and a non-human primate model to monitor the SSIOAC treatment in real-time and post-treatment. Melphalan and carboplatin (another chemotherapeutic used to treat retinoblastoma via SSIOAC) triggered migration, proliferation, and apoptosis when used to treat human retinal endothelial cells. Melphalan was associated with increased adhesion of leukocytes to human retinal endothelial cells, and tended to increase with increased cell expression of adhesion proteins (ICAM-1) and soluble chemotactic factors (IL-8). Histopathology post-SSIOAC indicated vessel wall sloughing, leukostasis, and vessel occlusion. We have established an in vitro human cell culture model and a non-human primate model to evaluate strategies designed to obviate vascular side effects, and optimize the efficacy of SSIAOC and the drug preparations used in SSIOAC.
Intra-ophthalmic artery chemotherapy triggers vascular toxicity through endothelial cell inflammation and leukostasis.
Specimen part, Treatment
View SamplesSuper-selective intra-ophthalmic artery chemotherapy (SSIOAC) is an organ-specific drug-delivery strategy to treat retinoblastoma, the most common primary ocular malignancy in children. Unfortunately, recent clinical reports associate adverse vascular toxicities with SSIOAC using melphalan, the most commonly used chemotherapeutic. To explore the reason for the unexpected vascular toxicities, we have developed in vitro studies with human retinal endothelial cells to test the effects of the chemotherapeutics and a non-human primate model to monitor the SSIOAC treatment in real-time and post-treatment. Melphalan and carboplatin (another chemotherapeutic used to treat retinoblastoma via SSIOAC) triggered migration, proliferation, and apoptosis when used to treat human retinal endothelial cells. Melphalan was associated with increased adhesion of leukocytes to human retinal endothelial cells, and tended to increase with increased cell expression of adhesion proteins (ICAM-1) and soluble chemotactic factors (IL-8). Histopathology post-SSIOAC indicated vessel wall sloughing, leukostasis, and vessel occlusion. We have established an in vitro human cell culture model and a non-human primate model to evaluate strategies designed to obviate vascular side effects, and optimize the efficacy of SSIAOC and the drug preparations used in SSIOAC.
Intra-ophthalmic artery chemotherapy triggers vascular toxicity through endothelial cell inflammation and leukostasis.
Specimen part, Treatment
View SamplesWe used microarrays to detail the global program of gene expression during early hESC differentiation to mesendoderm using FBS, with and without RUNX1 depletion.
Transient RUNX1 Expression during Early Mesendodermal Differentiation of hESCs Promotes Epithelial to Mesenchymal Transition through TGFB2 Signaling.
Specimen part, Cell line
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