Microarray analyses provide a powerful approach to identify gene expression alterations following kidney transplantation. However, the heterogeneity of human kidney transplant specimens and the variation in sample preparation precludes conclusions regarding the underlying mechanisms of the observed alterations. We used a well defined experimental rat kidney transplantation model with consistent transplant and sample preparation procedures to analyze genome wide changes in gene expression after syngeneic (sTX) and allogeneic transplantation (aTX) four days after transplantation. Both interventions were associated with dramatic changes in gene expression. Genes and Pathways related to immune response were extremely up regulated after aTX. Several of the up regulated genes have been described by other groups and we are able to proof this in one study. But several genes are reported for the first time to be up regulated in expression after renal aTX. The function of these genes in acute rejection process has to be evaluated. On the other hand the up regulation of regulatory or protective genes indicates that regulatory mechanism are activated after aTX trying to down regulate the immune response or protect the tissue against the immune system. The study is capable to serve as a representative study in aTX mediated gene expression by covering the known transcriptional changes reported by other groups and identification of novel markers and pathways. Further analysis of the duplicated datasets by other groups can help for a better understanding of the mechanisms mediated by acute rejection and thereby increase the therapeutic threatment.
Activation of counter-regulatory mechanisms in a rat renal acute rejection model.
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View SamplesWe found the PRC2 component EZH2 to be upregulated by the pathognomonic fusion oncogene EWS-FLI1 in Ewing tumors and mesenchymal stem cells (Richter GH et al., Proc Natl Acad Sci U S A. 2009;106:5324-9). Downregulation of EZH2 by RNA interference in Ewing tumor cell lines suppressed oncogenic transformation in vitro and in vivo. These data suggest that EZH2 might play a central role in Ewing Tumor pathology.
Epigenetic maintenance of stemness and malignancy in peripheral neuroectodermal tumors by EZH2.
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Loss of the histone methyltransferase EZH2 induces resistance to multiple drugs in acute myeloid leukemia.
Specimen part, Cell line
View SamplesHere, we analyzed global gene expression changes that were associated with drug resistance in Acute Myeloid Leukemia using the Affymetrix microarray platform.
Loss of the histone methyltransferase EZH2 induces resistance to multiple drugs in acute myeloid leukemia.
Specimen part, Cell line
View SamplesEwing Tumors (ET) are highly malignant tumors, localized in bone or soft tissue and are molecularly defined by ews/ets translocations. We identified histone methyl-transferase Enhancer of Zeste, Drosophila, Homolog 2 (EZH2) to be increased in ET. EZH2s suppressive activity maintains stemness in normal and malignant cells. Here we found EZH2 to be upregulated by the pathognomonic fusion oncogene EWS-FLI1 in ET and mesenchymal stem cells. Downregulation of EZH2 by RNA interference in ET suppressed oncogenic transformation by inhibiting clonogenicity in vitro. Similarly, tumor development and metastasis in immunodeficient Rag2-/-C-/- mice was suppressed. EZH2-mediated gene silencing was shown to be dependent on histone deacetylase (HDAC) activity. Subsequent microarray analysis of EZH2 knock down, HDAC-inhibitor treatment and confirmation in independent assays revealed an undifferentiated phenotype maintained by EZH2 in ET. Downregulation of EZH2 decreased histone H3 lysine 27 trimethylation (H3K27me3) at target loci. EZH2 regulated stemness genes such as nerve growth factor receptor (NGFR) as well as genes involved in neuroectodermal differentiation (EMP1, EPHB2, GFAP, GAP43). These data suggest that EZH2 might play a central role in Ewing Tumor pathology shaping the oncogenicity and stem cell phenotype of this tumor presumably by epigenetic regulation.
EZH2 is a mediator of EWS/FLI1 driven tumor growth and metastasis blocking endothelial and neuro-ectodermal differentiation.
No sample metadata fields
View SamplesMany cases of acute myeloid leukemia (AML) are associated with mutational activation of RTKs such as FLT3. However, RTK inhibitors have limited clinical efficacy as single agents, indicating that AML is driven by concomitant activation of different signaling molecules. We used a functional genomic approach to identify RET, encoding an RTK not previously implicated in AML, as essential gene in different AML subtypes, and observed that RET-dependent AML cells show activation of RET signaling via ARTN/GFRA3 and NRTN/GFRA2 ligand/co-receptor complexes.
RET-mediated autophagy suppression as targetable co-dependence in acute myeloid leukemia.
Specimen part, Disease
View SamplesCancer cell phenotypes are partially determined by epigenetic specifications such as DNA methylation. Metastasis development is a late event in cancerogenesis and might be associated with epigenetic alterations. Here, we analyzed genome wide DNA methylation changes that were associated with pro-metastatic phenotypes in non-small cell lung cancer with Reduced Representation Bisulfite Sequencing. DNMT-inhibition by 5-Azacytidine at low concentrations reverted the pro-metastatic phenotype. 5-Azacytidine led to preferential loss of DNA methylation at sites that were DNA hypermethylated during the in vivo selection. Changes in DNA methylation persisted over time.
DNA methyltransferase inhibition reverses epigenetically embedded phenotypes in lung cancer preferentially affecting polycomb target genes.
Cell line
View SamplesHere, we analyzed global gene expression changes that were associated with pro-metastatic phenotypes in non-small cell lung cancer using the Affymetrix microarray platform.
DNA methyltransferase inhibition reverses epigenetically embedded phenotypes in lung cancer preferentially affecting polycomb target genes.
Cell line
View SamplesThe biology of chronic myeloid leukemia (CML)-stem cells is still incompletely understood. Therefore, we previously developed an inducible transgenic mouse model in which stem cell targeted induction of BCR-ABL expression leads to chronic phase CML-like disease. Here, we now demonstrate that the disease is transplantable using BCR-ABL positive LSK cells (lin-Sca-1+c-kit+). Interestingly, the phenotype is enhanced when unfractionated bone marrow (BM) cells are transplanted. However, neither progenitor cells (lin-Sca-1-c-kit+) nor mature granulocytes (CD11b+Gr-1+), or potential stem cell niche cells were able to transmit the disease or alter the phenotype. The phenotype was largely independent of BCR ABL priming prior to transplant. However, BCR-ABL abrogated the potential of LSK cells to induce full blown disease in secondary recipients. Subsequently, we found that BCR-ABL increased the fraction of multipotent progenitor cells (MPP) at the expense of long term HSC (LT-HSC) in the BM. Microarray analyses of LSK cells revealed that BCR-ABL alters the expression of genes involved in proliferation, survival, and hematopoietic development. Our results suggest that BCR-ABL induces differentiation of LT-HSC and decreases their self renewal capacity. Furthermore, reversion of BCR-ABL eradicates mature cells while leukemic stem cells persist, giving rise to relapsed CML upon re-induction of BCR-ABL.
BCR-ABL enhances differentiation of long-term repopulating hematopoietic stem cells.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Increased DNA methylation of Dnmt3b targets impairs leukemogenesis.
Specimen part
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