Project description:Control of oxidative stress in the bone marrow (BM) is key for maintaining the balance between self-renewal, proliferation, and differentiation of hematopoietic cells. Breakdown of this regulation can lead to diseases characterized by BM failure such as the myelodysplastic syndromes (MDS). To better understand the role of oxidative stress in MDS development, we compared protein carbonylation as an oxidative stress marker in BM of patients with MDS and control subjects, and also patients with MDS under treatment with the iron chelator deferasirox.
Project description:The progressive mechanism of myelodysplastic syndrome (MDS) remains unknown. We report that ROBO1 and ROBO2 are identified as novel progression-related somatic mutations using whole-exome and targeted sequencing in six of 16 (37.5%) paired MDS patients undergoing disease progression. To investigated the effect of ROBO1 or ROBO2 on ROBO1/2 CN number and LOH, we employed a Cytosan 750K chip to analyze the copy-number variations (CNVs) and loss of heterogeneity (LOH) in MDS patients with ROBO1&2 mutations. Copy number and LOH analysis of Affymetrix CytoScan 750K array was performed for 14 MDS patients with ROBO1 or ROBO2 mutations
Project description:Myelodysplastic syndromes (MDS) are a heterogenous group of hematopoietic stem cell disorders characterized by dysplastic blood cell formation and peripheral blood cytopenias. Up to 30% of patients with MDS will progress to a highly chemotherapy-resistant secondary acute myeloid leukemia (sAML). We identified mutations in U2AF1 in MDS patients and patients with U2AF1 mutations are at an increased risk of developing sAML.
Project description:Myelodysplastic syndromes (MDS) are a heterogenous group of hematopoietic stem cell disorders characterized by dysplastic blood cell formation and peripheral blood cytopenias. Up to 30% of patients with MDS will progress to a highly chemotherapy-resistant secondary acute myeloid leukemia (sAML). We identified mutations in U2AF1 in MDS patients and patients with U2AF1 mutations are at an increased risk of developing sAML. We identified mutations in U2AF1 in patients with MDS and hypothesized that U2AF1 mutations may represent a novel mechanism that could alter gene expression in MDS. To elucidate gene expression changes associated with U2AF1 mutations, we analyzed the global mRNA expression profile obtained from bone marrow CD34+ cells purified from 5 MDS patients with a U2AF1 mutation, 10 MDS patients without a mutation, and 4 normal donors.
Project description:Myelodysplastic syndromes (MDS) are uncommon entities, heterogeneous clinically and cytogenetically. Recently, a new drug, Lenalidomide, has demonstrated to be very effective in patients with MDS and 5q- reaching 70% of hematological responses whereas patients with MDS without 5q- has only 20-30% of hematological responses. The aim of the present study is to determine genetic alteration in this subset of patients, and describe candidate genes related with response or resistance to Lenalidomide.
Project description:Myelodysplastic syndromes (MDS) are uncommon entities, heterogeneous clinically and cytogenetically. Recently, a new drug, Lenalidomide, has demonstrated to be very effective in patients with MDS and 5q- reaching 70% of hematological responses whereas patients with MDS without 5q- has only 20-30% of hematological responses. The aim of the present study is to determine genetic alteration in this subset of patients, and describe candidate genes related with response or resistance to Lenalidomide. The aim of the present study is to determine genetic alteration in this subset of patients, and describe candidate genes related with response or resistance to Lenalidomide. Copy number analysis of Affymetrix GenomeWide SNP 6.0 arrays was performed for 2 patients with MDS an isolated 5q- by conventional cytogenetics. There are also 2 samples from separated CD3+ lymphocytes, which were used as references for copy number and LOH inference.
Project description:Genome-wide expression and methylation profiling identifies novel targets with aberrant hypermethylation and reduced expression in low-risk myelodysplastic syndromes (MDSs). Gene expression profiling signatures may be used to classify the subtypes of Myelodysplastic syndrome (MDS) patients. However, there are few reports on the global methylation status in MDS. The integration of genome-wide epigenetic regulatory marks with gene expression levels would provide additional information regarding the biological differences between MDS and healthy controls. Gene expression and methylation status were measured using high-density microarrays. A total of 552 differentially methylated CpG loci were identified as being present in low-risk MDS; hypermethylated genes were more frequent than hypomethylated genes. In addition, mRNA expression profiling identified 1005 genes that significantly differed between low-risk MDS and the control group. Integrative analysis of the epigenetic and expression profiles revealed that 66.7% of the hypermethylated genes were underexpressed in low-risk MDS cases. Gene network analysis revealed molecular mechanisms associated with the low-risk MDS group, including altered apoptosis pathways. The two key apoptotic genes BCL2 and ETS1 were identified as silenced genes. In addition, the immune response and micro RNA biogenesis were affected by the hypermethylation and underexpression of IL27RA and DICER1. Our integrative analysis revealed that aberrant epigenetic regulation is a hallmark of low-risk MDS patients and could have a central role in these diseases. Low-risk MDS patients and age-matched controls without haematological malignancies were included in the study. Mononuclear cells were isolated from bone marrow samples of low-risk MDS patients and controls by density gradient (Ficoll). A cohort of 18 patients with low-risk MDS and seven controls were included in a simultaneous integrative study of methylation and expression, while the whole series was used as a control group of expression data.