MARCH Study DAC, Vyas Group, University of Oxford
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ABSTRACT:
PROVIDER: EGAC00001003303 | EGA |
REPOSITORIES: EGA
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Project description:Reversal of gene promoter DNA hypermethylation and associated abnormal gene silencing is an attractive approach to cancer therapy. The DNA methylation inhibitor, decitabine (5-aza-2'-deoxycitidine), is proving efficacious for hematological neoplasms especially at lower, less toxic, doses. Experimentally, high doses induce rapid DNA damage and cytotoxicity, but these may not explain the prolonged time to response seen in patients. Transient exposure of leukemic and solid tumor cells to clinically-relevant nanomolar doses, without causing immediate cytotoxicity or apoptosis, produces sustained reduced tumorigenicity, and for leukemia cells, diminished long-term self-renewal. These effects appear triggered by cellular reprogramming and include sustained decreases in promoter DNA methylation with associated gene re-expression, and anti-tumor changes in multiple key cellular regulatory pathways, most of which are high priority targets for pharmacologic anti-cancer strategies. Thus, low dose decitabine regimens appear to have broad applicability for cancer management. [Gene expression profiling] Leukemia cell lines Kasumi-1 and KG1A are treated with 10nM DAC during 72 hours and gene expression was assayed at day 3, 7 and 14 after the start of the treatment. Appropriate mock treated samples were used as control in each case. In addition, Kasumi-1 cells were also treated with a higher dose of DAC (500nM), 100nM ARA-C and 300 nM TSA, again controlled against mock treated Kasumi-1 cells, to separate dose and agent dependent effects. MCF7 was studied as an example of a solid tumor cell line. Therefore MCF7 cells were treated with 100nM DAC and results were assayed at day 1, day 3 and day 10. [Methylation profiling] The effects of the demethylating agent DAC were studied in the leukemia cell line Kasumi-1 over a 28 day time course. Intermediate time points were studied at days 3, 7, 14 and 21. These results were verfied in KG1A and KG1 leukemia cell lines, at one selected time point. The effects on one primary sample were also studied. Four normal leukemia samples (PL1, 2, 4 and 5) were used as general controls. The effect of DAC was compared to ARA-C, TSA. Both mock treated and day 3 DAC treated Kasumi-1 cells were repeated. These results were verified at one selected time point for the DAC treated MCF7 breast cancer cell line.
2012-03-21 | E-GEOD-20945 | biostudies-arrayexpress
Project description:Data Access Committee EGAC00001000667
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Project description:Aberrant expression of microRNA (miRNA) has been reported in various cancers. To clarify the role of miRNA in gastric carcinogenesis, we performed miRNA microarray analysis and investigated expressional changes of miRNAs in a 5-aza-2'-deoxycytidine (DAC)-treated gastric cancer cell line, KATO-ІІІ.
2010-01-20 | GSE16006 | GEO
Project description:We observed gene expression difference between different groups after MDA-MB-231 treated with DMSO, 10 μM DAC, 1 μM DEX, or DAC+DEX. Data obtained from high-throughput sequencing (Illumina NovaSeq 6000 platform) were transformed into raw sequenced reads by CASAVA base calling and stored in FASTQ format. Gene expression of each groups are listed in raw data files. Some different expression genes between two groups are further validated with qRT-PCR.
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Project description:We found frequent epigenetic silencing of microRNA-34b/c in human colorectal cancer. Introduction of miR-34b/c into a colorectal cancer cell line induced significant changes in gene expression profile. We also found overlap between the genes downregulated by miR-34b/c and those downregulated by DAC. Keywords: dose response A colorecal cancer cell line HCT116 was transfected with miR-34b or -c precursor or negative control. Also, HCT116 was treated with 5-aza-2'-deoxycytidine (DAC) or mock. Genes up- or downregulated by miR-34b/c and those by DAC was compared.
2008-04-30 | E-GEOD-10455 | biostudies-arrayexpress
Project description:Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy that resists current treatments. To test epigenetic therapy against this cancer we used the DNA demethylating drug 5-aza-2’-deoxycytidine (DAC) in a KrasLSL-G12D; p53LSL-R270H/+; Pdx1-cre; Brca1flex2/flex2 (KPC-Brca1) mouse model of aggressive stroma-rich PDAC. In untreated tumors, we found globally decreased 5-methyl-cytosine (5mC) in malignant epithelial cells and in cancer-associated myofibroblasts (CAFs), and increased amounts of 5-hydroxymethyl-cytosine (5HmC) in CAFs, in progression from pancreatic intraepithelial neoplasia (PanIN) to PDAC. DAC further reduced DNA methylation and slowed PDAC progression, markedly extending survival in an early treatment protocol and significantly though transiently inhibiting tumor growth when initiated later, without adverse side effects. Escaping tumors contained areas of sarcomatoid transformation with disappearance of CAFs. Mixing-allografting experiments and proliferation indices showed that DAC efficacy was due to inhibition of both the malignant epithelial cells and the stromal CAFs. Expression profiling and immunohistochemistry highlighted DAC-induction of STAT1 in the tumors, and DAC plus gamma-interferon produced an additive anti-proliferative effect on PDAC cells. DAC induced strong expression of the testis antigen DAZL in CAFs. These data show that DAC is effective against PDAC in vivo and provide a rationale for future studies combining hypomethylating agents with cytokines and immunotherapy. Treatment of a short-term explant culture of malignant epithelial cells from a KPC-Brca1 mouse pancreatic carcinoma, with 0.5 micromolar 5-aza-dC (decitabine; DAC) for 48 hours. The experiment includes 3 replicate plates untreated and 3 replicates treated.
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Project description:Data Access Committee EGAC00001000334
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Project description:Melanoma progression model:DAC-mediated gene expression Keywords: other
2005-07-20 | GSE1793 | GEO