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The Human Epigenetic Drug Database (HEDD) is a comprehensive web-based database for epigenetic drugs, which focuses on the storage and integration of epigenetic drug datasets that were obtained from laboratory experiments that is essential for understanding the mechanism of action of these epigenetic drugs at a systematic level.

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A687V EZH2 is a driver of histone H3 lysine 27 (H3K27) hyper-trimethylation

Drug Name:GSK126
Drug Category:HMTi
Sample Type:human lymphoblastic leukemia cell lines (SUP-B8, NALM-6)
Condition: lymphoblastic leukemia
Experiment Type:Expression profiling by array
Experiment Platform:GPL570 [HG-U133_Plus_2] Affymetrix Human Genome U133 Plus 2.0 Array
Description:The EZH2 methyltransferase silences gene expression through methylation of histone H3 on lysine 27 (H3K27). Recently, EZH2 mutations have been reported at Y641, A677, and A687 in non-Hodgkin lymphoma. Although the Y641F/N/S/H/C and A677G mutations exhibit clearly increased activity with substrates dimethylated at lysine 27 (H3K27me2), the A687V mutant has been shown to prefer a monomethylated lysine 27 (H3K27me1) with little gain of activity toward H3K27me2. Herein, we demonstrate that despite this unique substrate preference, A687V EZH2 still drives increased H3K27me3 when transiently expressed in cells. However, unlike the previously described mutants that dramatically deplete global H3K27me2 levels, A687V EZH2 retains normal levels of H3K27me2. Sequencing of B-cell-derived cancer cell lines identified an acute lymphoblastic leukemia cell line harboring this mutation. Treatment of A687V EZH2-mutant cells with GSK126, a selective EZH2 inhibitor, was associated with a global decrease in H3K27me3, robust gene activation, caspase activation, and decreased proliferation. Structural modeling of the A687V EZH2 active site suggests that the increased catalytic activity with H3K27me1 may be due to a weakened interaction with an active site water molecule that must be displaced for dimethylation to occur. These findings suggest that A687V EZH2 likely increases global H3K27me3 indirectly through increased catalytic activity with H3K27me1 and cells harboring this mutation are highly dependent on EZH2 activity for their survival.
PubmedID:25253781
Citation:Ott HM;Graves AP;Pappalardi MB; Huddleston M;Halsey WS;Hughes AM;Groy A; Dul E; Jiang Y;Bai Y; Annan R; Verma SK; Knight SD; Kruger RG;Dhanak D;Schwartz B;Tummino PJ;Creasy CL;McCabe MT. A687V EZH2 is a driver of histone H3 lysine 27 (H3K27) hypertrimethylation. Mol Cancer Ther 2014 Dec;13(12):3062-73.
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The Human Epigenetic Drug Database (HEDD) is a comprehensive web-based database for epigenetic drugs, which focuses on integrating epigenetic drug studies based Omics data from high through experiments that is essential for understanding the mechanism of action of these epigenetic drugs at a systematic level.

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©2016 Group of Computational Epigenomics and Bioinformatics, College of Life Science, Jilin Normal University, China

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