microRNAs, important regulators of cell proliferation and apoptosis, have been shown to be involved in the pathogenesis of acute myeloid leukemia in adulthood AML. However, comprehensive studies in AML of children and adolescents are missing so far. We investigated the miRNA expression profiles of different AML subtypes from 102 pediatric patients in comparison to CD34+ cells from healthy donors and adult AML patients, in order to identify differentially expressed miRNAs. Pediatric samples with core factor binding acute myeloid leukemia and promyelocytic leukemia could be distinguished from each other and MLL rearranged AML subtypes by 9 and 18 miRNAs, respectively. miR-126, -146a, -181a/b, -100, and miR-125b were identified as highest differentially expressed with marked difference of expression between pediatric and adulthood samples of the same cytogenetic subgroup. We next isolated the miRNA targeting complex from t(8;21) and t(15;17) cell line models and comprehensively identified bound miRNAs and targeted mRNAs by a newly devised immunoprecipitation assay followed by rapid microarray detection. Our findings indicate separate binding preferences for the four human Argonaute proteins. Subsequent bioinformatic analysis revealed a concerted action of different Ago proteins in the regulation of AML-relevant pathways, providing an experimental based database of miRNA-mRNA target interaction in Argonaute proteins.
MicroRNAs distinguish cytogenetic subgroups in pediatric AML and contribute to complex regulatory networks in AML-relevant pathways.
Specimen part
View SamplesGlioblastoma is the most common primary malignant brain tumor occurring in the central nervous system and is characterized by rapid proliferation, genetic aberrations and poor response to treatment. The classical genetic alterations in glioblastoma target pathways governing cellular proliferation, cellular survival, invasion and angiogenesis. In this study, the regulation of glioblastoma-relevant pathways by small non-coding RNAs was analyzed by identification of Argonaute protein-associated microRNAs and mRNAs. We utilized a highly controlled method termed PAR-CLIP-Array by biochemical isolation of cross-linked ribonucleoprotein complexes with monoclonal antibodies specific for individual Argonaute proteins followed by microarray detection. We demonstrate here that the different Argonaute proteins bind different subsets of miRNAs and mRNAs in a glioblastoma cell line model. By extending our study generating miRNA-mRNA network interaction models we could further show, that different Argonaute proteins act in concert to regulate glioblastoma-relevant pathways. We therefore provide novel insights into glioblastoma regulation by microRNAs.
No associated publication
Specimen part, Disease, Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
The impact of TEL-AML1 (ETV6-RUNX1) expression in precursor B cells and implications for leukaemia using three different genome-wide screening methods.
Specimen part, Disease, Disease stage, Cell line
View SamplesAndrogenic steroids are increasingly used for hormone therapy of postmenopausal women and abused as life style drugs and for doping purposes, though knowledge about associated health risks in females is very limited. In order to understand more about short- and long-term androgen effects on a molecular level, we have analyzed hepatic gene expression in female C57BL/6 mice immediately after subcutaneous treatment with testosterone for 3 weeks and after 12 weeks hormone withdrawal using Affymetrix array technology and quantitative real-time RT-PCR. Among about 14,000 genes examined, 48 were up- and 65 genes were downregulated by testosterone after 3-weeks treatment and about 50% of these changes persisted even 12 weeks after testostrone withdrawal. In addition to obvious risks such as induction of hepatocellular carcinomas and virilization of liver metabolism, testosterone induced a series of changes, as e.g. dysregulation of hepatic gene expression due to incomplete conversion of female to male phenotype in particular downregulation of cytochrom P450 isoforms and sulfotransferases. As a long-term testosterone effect, transcripts emerged in the liver that are normally specific for the exocine pancreas including amylase 2, ribonuclease 1, and several trypsin-, chymotrypsin-, and elastase-like proteases. This transdifferentiation of hepatic to exocrine pancreatic tissue indicates that testosterone can initiate long-lasting differentiation programs, which once induced progress even after androgen withdrawal. This may have far-reaching consequences difficult to foresee implying long-term hazards of testosterone-treatment for female health that have not been taken into account yet.
Testosterone-induced upregulation of miRNAs in the female mouse liver.
Sex, Specimen part, Treatment
View SamplesWe identified directly and indirectly regulated target genes utilizing an inducible TEL-AML1 system derived from the murine pro B-cell line BA/F3 and a monoclonal antibody directed against TEL-AML1. By integration of promoter binding identified with ChIP-on-chip, gene expression and protein output through microarray technology and stable labelling of amino acids in cell culture (SILAC), we identified directly and indirectly regulated targets of the TEL-AML1 fusion protein.
The impact of TEL-AML1 (ETV6-RUNX1) expression in precursor B cells and implications for leukaemia using three different genome-wide screening methods.
Cell line
View SamplesReactive oxygen species (ROS) are key signalling molecules that regulate growth and development and coordinate responses to biotic and abiotic stresses. ROS homeostasis is controlled through a complex network of ROS production and scavenging enzymes. Recently, the first genes involved in ROS perception and signal transduction have been identified and, currently, we are facing the challenge to uncover the other players within the ROS regulatory gene network. The specificity of ensuing cellular responses depends on the type of ROS and their subcellular production sites. Various experimental systems, including catalase-deficient plants, in combination with genome-wide expression studies demonstrated that increased hydrogen peroxide (H2O2) levels significantly affect the transcriptome of plants and are capable of launching both defence responses and cell death events.
Spatial H2O2 signaling specificity: H2O2 from chloroplasts and peroxisomes modulates the plant transcriptome differentially.
Age, Specimen part
View SamplesLittle is known about the effects of lenalidomide therapy on Bone Marrow HSPCs in patients with Multiple Myeloma. In this experiment, we examined the gene expression changes associated with a six months
No associated publication
Specimen part, Disease stage, Subject, Time
View SamplesTGR5 (Gpbar1) is a G protein-coupled receptor responsive to bile acids (BAs), which is expressed in different non-parenchymal cells of the liver, including biliary epithelial cells, liver-resident macrophages, sinusoidal endothelial cells (LSECs) and activated hepatic stellate cells (HSCs). Mice with targeted deletion of TGR5 are more susceptible towards cholestatic liver injury induced by cholic acid-feeding and bile duct ligation, resulting in a reduced proliferative response and increased liver injury. Conjugated lithocholic acid (LCA) represents the most potent TGR5 BA ligand and LCA-feeding has been used as a model to rapidly induce severe cholestatic liver injury in mice. Thus, TGR5 knockout (KO) mice and wildtype littermates were fed a diet supplemented with 1%LCA for 84 hours. Liver injury and gene expression changes induced by the LCA-diet revealed an enrichment of pathways associated with inflammation, proliferation and matrix remodelling. Knockout of TGR5 in mice caused upregulation of endothelin-1 (ET-1) expression in the livers. Analysis of TGR5-dependent ET-1 signalling in isolated LSECs and HSCs demonstrated that TGR5 activation reduces ET-1 expression and secretion from LSECs and triggers internalization of the ET-1 receptor in HSCs dampening ET-1 responsiveness. Thus, we identified two independent mechanisms by which TGR5 inhibits ET-1 signalling and modulates portal pressure.
The G Protein-Coupled Bile Acid Receptor TGR5 (Gpbar1) Modulates Endothelin-1 Signaling in Liver.
Sex
View SamplesIn this study we investigated the changes in mRNA expression upon treatment of SH-SY5Y cells to 10M cisplatin for 72h.
Calcium-regulatory proteins as modulators of chemotherapy in human neuroblastoma.
Specimen part, Cell line, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Nijmegen Breakage Syndrome fibroblasts and iPSCs: cellular models for uncovering disease-associated signaling pathways and establishing a screening platform for anti-oxidants.
Specimen part, Disease, Disease stage, Cell line
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