Purpose:To identify resistance mechanisms for the chemotherapeutic drug fludarabine in chronic lymphocytic leukemia (CLL), as innate and acquired resistance to fludarabine-based chemotherapy represents a major challenge for long-term disease control. Methods: We employed piggyBac transposon-mediated mutagenesis, combined with next-generation sequencing, to identify genes that confer resistance to fludarabine in a human CLL cell line. Results: RNA-seq profiling of fludarabine-resistant cells suggested deregulated MAPK signaling as involved in mediating drug resistance in CLL. Overall design: To address if the fludarabine-resistant HG3 cells were transcriptionally different at a global level compared to their parental cells, we performed RNA-sequencing of three pairs of HG3 pools
Transposon Mutagenesis Reveals Fludarabine Resistance Mechanisms in Chronic Lymphocytic Leukemia.
No sample metadata fields
View SamplesIn order to gain insight into the molecular pathogenesis of the myelodysplastic syndromes (MDS), we performed global gene expression profiling and pathway analysis on the hematopoietic stem cells (HSC) of 183 MDS patients as compared with the HSC of 17 healthy controls. The most significantly deregulated pathways in MDS include interferon signaling, thrombopoietin signaling and the Wnt pathway. Among the most significantly deregulated gene pathways in early MDS are immunodeficiency, apoptosis and chemokine signaling, whereas advanced MDS is characterized by deregulation of DNA damage response and checkpoint pathways. We have identified distinct gene expression profiles and deregulated gene pathways in patients with del(5q), trisomy 8 or 7/del(7q). Patients with trisomy 8 are characterized by deregulation of pathways involved in the immune response, patients with 7/del(7q) by pathways involved in cell survival, whilst patients with del(5q) show deregulation of integrin signaling and cell cycle regulation pathways. This is the first study to determine deregulated gene pathways and ontology groups in the HSC of a large group of MDS patients. The deregulated pathways identified are likely to be critical to the MDS HSC phenotype and give new insights into the molecular pathogenesis of this disorder thereby providing new targets for therapeutic intervention.
Deregulated gene expression pathways in myelodysplastic syndrome hematopoietic stem cells.
Specimen part, Disease
View SamplesLittle is known about the pan-microvascular transcriptome, particularly considering gene transcripts and their encoded proteins that can be considered as vascular-selective in their expression.
Identification of a core set of 58 gene transcripts with broad and specific expression in the microvasculature.
No sample metadata fields
View SamplesWe aimed to determine the impact of the common mutations on the transcriptome in myelodysplastic syndromes (MDS). We linked genomic data with gene expression microarray data and we deconvoluted the expression of genes into contributions stemming from each genetic and cytogenetic alteration, providing insights into how driver mutations interfere with the transcriptomic state. We modelled the influence of mutations and expression changes on diagnostic clinical variables as well as survival.
Combining gene mutation with gene expression data improves outcome prediction in myelodysplastic syndromes.
Specimen part, Disease
View SamplesMutations of the splicing factor U2AF1 are frequent in the myeloid malignancy myelodysplastic syndromes (MDS) and in other cancers. Patients with MDS suffer from peripheral blood cytopenias, including anemia, and increasing bone marrow blasts. We investigated the impact of the common U2AF1 S34F mutation on cellular function and mRNA splicing in the main cell lineages affected in MDS. We demonstrated that U2AF1 S34F expression in human hematopoietic progenitors impairs erythroid differentiation, and skews granulomonocytic differentiation towards granulocytes. RNA-sequencing of erythroid and granulomonocytic colonies revealed that U2AF1 S34F induced a higher number of cassette exon splicing events in granulomonocytic than erythroid cells, and altered mRNA splicing of many transcripts (expressed in both cell types) in a lineage-specific manner. The introduction of isoform changes identified in the target genes H2AFY and STRAP into hematopoietic progenitors recapitulated phenotypes associated with U2AF1 S34F expression in erythroid and/or granulomonocytic cells, suggesting a causal link. Importantly, we provided evidence showing that isoform modulation of the U2AF1 S34F target genes H2AFY and STRAP rescues the erythroid differentiation defect in U2AF1 S34F MDS cells, raising the possibility of using splicing modulators therapeutically. These data have critical implications for understanding MDS phenotypic heterogeneity, and for the development of new targeted therapies. Overall design: RNA sequencing was performed to identify the aberrant splicing events associated with U2AF1 S34F mutation (n=3) compared to U2AF1 wild-type (n=3) and empty vector control (n=3) in BFU-E and CFU-G/M colonies respectively.
The U2AF1S34F mutation induces lineage-specific splicing alterations in myelodysplastic syndromes.
Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Genome-wide screen of cell-cycle regulators in normal and tumor cells identifies a differential response to nucleosome depletion.
Specimen part, Cell line
View SamplesGene-expression in siRNA treated U2OS and hTERT-RPE1 cells showed that CASP8AP2, NPAT and HINFP do not regulate expression of each other, and do not have any common target genes, except histones. Most histone genes are downregulated in U2OS cells following loss of CASP8AP2, NPAT or HINFP. In normal cells, highly-expressed histone genes were downregulated, albeit less than in tumor cells following loss of CASP8AP2. The p53 target genes were upregulated relatively late, clearly after the changes in expression of histone genes were observed.
Genome-wide screen of cell-cycle regulators in normal and tumor cells identifies a differential response to nucleosome depletion.
Cell line
View SamplesMultiple sclerosis is a chronic, inflammatory, demyelinating disease of the central nervous system in which macrophages and microglia play a central role. During active multiple sclerosis foamy macrophages and microglia, containing degenerated myelin, are abundantly found in demyelinated areas. Recent studies have described an altered macrophage phenotype after myelin internalization. However, by which mechanisms myelin affects the phenotype of macrophages and how this phenotype can influence lesion progression is unclear.
Myelin-derived lipids modulate macrophage activity by liver X receptor activation.
Specimen part, Treatment
View SamplesSF3B1, SRSF2 and U2AF1 are the most frequently mutated splicing factor genes in MDS. We have performed a comprehensive analysis to determine the impact of these commonly mutated splicing factors on pre-mRNA splicing in the stem/progenitor cells and in the erythroid and myeloid precursors in splicing factor mutant MDS. Using RNA-seq, we determined the aberrantly spliced genes and dysregulated pathways in bone marrow CD34+ cells of a large group of 82 MDS patients. Splicing factor mutations in MDS result in different mechanistic alterations in splicing and largely affect different genes, but these converged in common dysregulated pathways and cellular processes, including RNA splicing, translation and mitochondrial dysfunction, indicating that these mutations operate through common mechanisms in MDS. Many of these dysregulated pathways and cellular processes can be linked to the known disease pathophysiology and to the phenotypes associated with splicing factor mutations in MDS, whilst several others have not been previously associated with MDS, such as sirtuin signalling. Overall design: RNA-sequencing was performed on bone marrow CD34+ hematopoeitic stem and progenitor cells from patients with myelodysplastic syndrome and healthy controls to identify differential splicing between samples with mutations in the splicing factor SF3B1, SRSF2 or U2AF1 comparative to samples from myelodysplactic syndrome patients without mutations in these splicing factors and healthy controls. Processed data for the CD34+ hematopoeitic stem and progenitor cells are available in the files: CPM_table.txt.gz, Count_table.txt.gz and TPM_table.txt.gz. RNA-sequencing was also performed on monocytic, granulocytic and erythroid precursors from the bone marrow of patients with myelodysplastic syndrome and healthy controls to identify aberrant splicing in samples with mutations in splicing factors SF3B1 and SRSF2 comparative from healthy controls. Processed data for the monocytic, granulocytic and erythroid precursors are available in the files: CPM_table_fractions.txt, Count_table_fractions.txt and TPM_table_fractions.txt.
Impact of spliceosome mutations on RNA splicing in myelodysplasia: dysregulated genes/pathways and clinical associations.
Specimen part, Disease, Subject
View SamplesThe ACBP knockout were created by targeted disruption of the gene in mice. The expression profiling was performed on liver tissue from ACBP-/- (KO) and +/+ (WT) mice at the age of 21 days, which in our study is the time immediately before weaning. The mice used for this experiment were taken directly away from their mother. Thus, having free access to chow and breast milk until sacrificed at 8-11am
Disruption of the acyl-CoA-binding protein gene delays hepatic adaptation to metabolic changes at weaning.
Specimen part
View Samples