Project description:The whole exome sequencing experiment is part of the study: “Analysis of 5-azacytidine resistance models reveals a set of targetable pathways”. In the study we generated myelodysplastic syndrome/acute myeloid leukemia (MDS/AML) OCI-M2 cell lines as well as patient-derived bone marrow cell lines that are resistant to hypomethylating therapy by 5-azacytidine (AZA). By integrated analysis of expression and mutation data obtained from these samples we have identified multiple signaling pathways whose modulation by specific small molecule inhibitors significantly block proliferation of AZA-resistant cell lines without increasing their sensitivity to AZA. The understanding of the molecular mechanisms which characterize the AZA-R phenotype can be used for broadening therapeutic options at progressing states during AZA therapy.
Project description:Azacitidine (AZA) is a hypomethylating drug used to treat disorders associated with myelodysplasia and related neoplasms. Approximately 50% of patients do not respond to AZA and have very poor outcomes. It is of great interest to identify predictive biomarkers for AZA responsiveness. Therefore, we searched for specific genes whose expression level was associated with response status.Using microarrays, we analyzed gene expression patterns in bone marrow CD34+ cells from 32 patients with myelodysplastic syndromes, chronic myelomonocytic leukemia, and acute myeloid leukemia with myelodysplasia-related changes before AZA therapy. Total RNA was isolated from bone marrow CD34+ cells obtained from myelodysplasia and related neoplasms patients who underwent treatment with 5-azacytidine (AZA, Vidaza). Using Illumina Human HT-12 v. 4 microarrays, we assayed gene expression profiles in patient CD34+ cells before AZA treatment in order to collect basic data for search for markers of the prediction of therapy response.
Project description:Epigenetic changes accompany tumorigenesis and are required for tumor maintenance. Modulation of DNA methylation state, histone acetylation, and histone methylation, as well as reversal of disease-associated epigenetic state aberrations, can be disruptive to malignant disease progression. We produced lipophilic prodrugs of decitabine, which is a DNA methyltransferase inhibitor and is efficacious in treatment of myelodysplastic syndromes when dosed subcutaneously. Comparison of parent and prodrug activities in vitro and in vivo revealed comparable effects and unveiled several novel features of nucleoside analog molecular activity in vitro. HCT116 were treated for 72 hour with Decitabine, Azacytidine and various prodrugs in duplicates at different dose concentrations. Cells were also treated with DMSO as control (quadrpulets), RNA was extracted and samples were hybridized to Affymetrix Hu133plus 2.0 arrays.
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.
Project description:Therapy resistance represents a major clinical challenge in acute myeloid leukemia (AML). Here we define a “MitoScore” signature that identifies high mitochondrial oxidative phosphorylation (OxPHOS) in vivo and in AML patients. Primary AML cells with cytarabine (AraC) resistance and high MitoScore relied on mitochondrial Bcl2 and were highly sensitive to venetoclax (VEN) plus AraC (but not to VEN plus azacytidine, AZA). Single-cell transcriptomics of VEN+AraC-residual cell populations revealed adaptive resistance associated with changes in OxPHOS, electron transport chain complex (ETC) and the TP53 pathway.
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 (using Methylated CpG Island Amplification and Microarrays, MCAM) and expression (using Affymetrix microarrays HG-U133 Plus 2), while the whole series was used as a control group of expression data.
Project description:This SuperSeries is composed of the following subset Series: GSE41130: Expression profiling of Low-Risk Myelodysplastic Syndromes (MDSs) GSE41215: Methylation profiling of Low-Risk Myelodysplastic Syndromes (MDSs) Refer to individual Series
Project description:The RNA sequencing experiment is part of the study: “Modulating Redox Balance Restores Azacytidine Efficacy in Hypomethylating Agent Resistant Disease.” In the study we generated myelodysplastic syndrome/acute myeloid leukemia (MDS/AML) OCI-M2 cell line that is resistant to hypomethylating therapy by 5-azacytidine (AZA). By modulation of the redox environment via modification of redox sensor KEAP1 using sulforaphane (SFN) in these cells we were able to restore sensitivity to AZA. We used RNA sequencing to define transcriptomic differences between AZA sensitive (AZA-S) and AZA resistant (AZA-R) cells and to characterize how the transcriptome is changing upon treatment of these cells with AZA, SFN and combination of both.