Effects of DNA methyltransferase inhibitors (DNMTIs) on MDS-derived cell lines
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ABSTRACT: To further investigate the action mechanisms of decitabine (DAC), the molecular pathways regulated by DAC were explored using the gene expression profile of MDS-L cells treated with 4 nM DAC or DMSO for 7 days. Genes whose expression changed by more than 2.0-fold following drug treatment were defined as regulated genes. 956 genes were up-regulated and 461 genes down-regulated in MDS-L cells treated with DAC (4 nM) as compared with the control. Gene expression profiling suggested that DAC significantly affects various gene biogroups, including cellular movement, inflammatory response, hematological system development and function, hematopoiesis, and cell death. Decitabine-induced gene expression in MDS-L cells was measured after 7 days exposure at dose of 4 nM. Three independent samples.
Project description:To further investigate the action mechanisms of decitabine (DAC), the molecular pathways regulated by DAC were explored using the gene expression profile of MDS-L cells treated with 4 nM DAC or DMSO for 7 days. Genes whose expression changed by more than 2.0-fold following drug treatment were defined as regulated genes. 956 genes were up-regulated and 461 genes down-regulated in MDS-L cells treated with DAC (4 nM) as compared with the control. Gene expression profiling suggested that DAC significantly affects various gene biogroups, including cellular movement, inflammatory response, hematological system development and function, hematopoiesis, and cell death.
Project description:In order to further study the mechanism of decitabine (DAC) on MDS cell lines, 1uM DAC was used to treat SKM-1 and MDS-L cell lines, and the molecular pathway changes regulated by DAC were explored. Genes whose expression changes more than 2.0 times after drug treatment are defined as regulated genes. Taking the intersection change of the two cell lines, it was found that compared with the control, 541 genes were up-regulated in the intersection of gene changes treated with DAC, and 762 genes were down-regulated. Gene expression profile analysis shows that DAC can significantly affect various cell biological processes, including antiviral response, immune response, inflammatory response and cell apoptosis.
Project description:Myelodysplastic syndromes (MDS) are a group of clonal myeloid neoplasms characterized by ineffective hematopoiesis and cytopenia. Hypomethylating agents (HMAs) play a central role in the treatment of high-risk MDS, but their mechanisms of action are diverse and not fully understood. To investigate the molecular mechanisms of HMA, an MDS cell line (MDS-L) was cultured with a non-toxic concentration of decitabine for 6 months and drug sensitivity, cell differentiation, and DNA methylation profiles were evaluated. Cells with long-term exposure to decitabine (MDS-L-DAC) were morphologically mature with nuclear lobulation and cytoplasmic granulation, accompanied by decreased expression of the CD34 surface antigen. MDS-L-DAC cells exhibited decreased WT1 expression and intense induction of apoptosis by DAC. DNA methylation array analysis revealed the demethylation of the membrane spanning 4-domains A3 (MS4A3) genes and microRNA-143 (MIR143) in MDS-L-DAC cells. MIR143 functions as a tumor suppressor through the MAPK/ERK pathway, and in MDS-L-DAC cells, decreased expression of KRAS and β-catenin was observed in response to the increased expression of MIR143. The differentiation of MDS cells and decreased expression of WT1 induced by long-term incubation with DAC may involve the restoration of function via demethylation of the MIR143 and MS4A3 gene promoters, which may contribute to eliminating the malignant phenotype through reductions in KRAS and β-catenin expression.
Project description:To evaluate the impact of DNA demethylating agents on our mouse MDS model, we chose 5-aza-2’-deoxycytidine, decitabine (DAC), one of the DNA demethylating agents, which is incorporated into DNA but not RNA and has 10-fold more potency in DNA demethylation than 5-azacitidine. We transplanted Tet2KD/KDEzh2Δ/Δ MDS cells into lethally irradiated secondary recipients and treated them with DAC (low dose DAC at 0.25mg/kg, 3 times a week, intraperitoneal injection), then purified LSK HSPCs and evaluated the expression profiles.
Project description:Azacitidine (AZA) and decitabine (DAC) are cytidine azanucleoside analogs with clinical activity in myelodysplastic syndromes (MDS) and potential activity in solid tumors. To better understand the mechanism of action of these drugs, we examined the effects of AZA and DAC in a panel of non-small cell lung cancer (NSCLC) cell lines. Of 5 NSCLC lines tested in a cell viability assay, all were sensitive to AZA (EC50 of 1.8M-bM-^@M-^S10.5 M-BM-5M), while only H1299 cells were equally sensitive to DAC (EC50 of 5.1 M-BM-5M). In the relatively DAC-insensitive cell line A549, both AZA and DAC caused DNA methyltransferase I depletion and DNA hypomethylation; however, only AZA significantly induced markers of DNA damage and apoptosis, suggesting that mechanisms in addition to, or other than, DNA hypomethylation are important for AZA-induced cell death. Cell cycle analysis indicated that AZA induced an accumulation of cells in sub-G1 phase, whereas DAC mainly caused an increase of cells in G2/M. Gene expression analysis of AZA- and DAC-treated cells revealed strikingly different profiles, with many genes distinctly regulated by each drug. In summary, while both AZA and DAC caused DNA hypomethylation, distinct effects were demonstrated on regulation of gene expression, cell cycle, DNA damage, and apoptosis. A549 and H1299 cells were treated with a dose range (0.3M-bM-^@M-^S3.0 M-NM-<M) of AZA or DAC for 48 hours, and effects on gene expression were assessed by microarray analysis.
Project description:Decitabine (DAC) is used clinically for myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). Our genome-wide CRISPR-dCas9 activation screen using MDS-derived AML cells shows that mitotic regulation plays a pivotal role in DAC resistance. DAC strongly induces abnormal mitosis (abscission failure or tripolar mitosis) in human myeloid tumors at clinical concentrations, especially in those with TP53 mutations and antecedent hematological disorders. This DAC-induced mitotic disruption and apoptosis are significantly attenuated in DNMT1-depleted cells. In contrast, the overexpression of Dnmt1, but not the catalytically inactive mutant, enhances DAC-induced mitotic defects in myeloid tumors. We also demonstrate that DAC-induced mitotic disruption is enhanced by pharmacological inhibition of the ATR-CLSPN-CHK1 pathway. These data challenge the current assumption that DAC inhibits leukemogenesis through DNMT1 inhibition and subsequent DNA hypomethylation, while highlighting the potent activity of DAC to perturb mitosis through aberrant DNMT1-DNA covalent bonds.
Project description:SKM-1 cells were cultured for 28 days in the absence or presence of low doses of the DNMT1 inhibitors DAC (10 nM) or AZA (100 nM). The experiment was carried in two independent set at different times, and with 2 replicates for each condition (Ctl, AZA, DAC) for a total of 12 samples. The SKM-1 cell line is derived from secondary AML arising from MDS, and is one the few representative in vitro models of MDS.
Project description:Acute myeloid leukemia (AML), and other myeloid malignancies, are frequently treated with hypomethylating agents like decitabine. Alterations in the epigenome, induced by decitabine, are likely to result in gene expression changes. The effects of decitabine have not been systemically studied using primary AML samples. We cultured 18 different primary AML samples for 7 days, the last 3 days of which included 100 nM decitabine (DAC) or 100 nm cytarabine (AraC). We hypothesized that decitabine treatment would result in detectable and consistent gene expression changes. For comparison, we also analyzed mRNA from cells treated with DMSO control (mock) and mRNA from uncultured cells taken at the time of diagnosis.
Project description:Decitabine (DAC) is used clinically for myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). To elucidate its exact mechanism of action, we performed a genome-wide CRISPR-dCas9 activation screen using MDS-derived AML cells and revealed that mitotic regulation plays a pivotal role in DAC resistance. DAC strongly induces abnormal mitosis (abscission failure or tripolar mitosis) in human myeloid tumors at clinical concentrations, especially in those with TP53 mutations and antecedent hematological disorders. This DAC-induced mitotic disruption and apoptosis are significantly attenuated in DNMT1-depleted cells. In contrast, the overexpression of Dnmt1, but not the catalytically inactive mutant, enhances DAC-induced mitotic defects in myeloid tumors. These data challenge the current assumption that DAC inhibits leukemogenesis through DNMT1 inhibition and subsequent DNA hypomethylation and highlight the potent activity of DAC to perturb mitosis through aberrant DNMT1-DNA covalent bonds. This clinically revised mode of action is enhanced by pharmacological inhibition of the ATR-CLSPN-CHK1 pathway.
Project description:The miRNA-related signaling pathways in MDS could be screened using high throughput bioinformatics analysis based on the miRNAs expression profile network. Here, we tried to identify the miRNAs-regulated pathways through a miRNA microarray in CD34+ cells from MDS patients. miRNA expression profile analysis was performed in 12 MDS patients and 6 normal controls using GeneChip® miRNA 3.0 Array, and diffirential miRNAs were identified.