Publications by authors named "Donghang Cheng"

Purpose: Clinical adoption of NK cell immunotherapy is underway for medulloblastoma and osteosarcoma, however there is currently little feedback on cell fate after administration. We propose magnetic particle imaging (MPI) may have applications for the quantitative detection of NK cells.

Procedures: Human-derived NK-92 cells were labeled by co-incubation with iron oxide nanoparticles (VivoTrax™) for 24 h then excess nanoparticles were washed with centrifugation.

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The RE1 silencing transcription factor (REST) is a driver of sonic hedgehog (SHH) medulloblastoma genesis. Our previous studies showed that REST enhances cell proliferation, metastasis and vascular growth and blocks neuronal differentiation to drive progression of SHH medulloblastoma tumors. Here, we demonstrate that REST promotes autophagy, a pathway that is found to be significantly enriched in human medulloblastoma tumors relative to normal cerebella.

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The coactivator associated arginine methyltransferase (CARM1) promotes transcription, as its name implies. It does so by modifying histones and chromatin bound proteins. We identified nuclear factor I B (NFIB) as a CARM1 substrate and show that this transcription factor utilizes CARM1 as a coactivator.

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Automatic modulation discrimination (AMC) is one of the critical technologies in spatial cognitive communication systems. Building a high-performance AMC model in intelligent receivers can help to realize adaptive signal synchronization and demodulation. However, tackling the intra-class diversity problem is challenging to AMC based on deep learning (DL), as 16QAM and 64QAM are not easily distinguished by DL networks.

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Radar signal anomaly detection is an effective method to detect potential threat targets. Given the low of the traditional AE model and the complex network of GAN, an anomaly detection method based on ResNet-AE is proposed. In this method, CNN is used to extract features and learn the potential distribution law of data.

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Arginine methylation is a post-translational modification that is implicated in multiple biological functions including transcriptional regulation. The expression of protein arginine methyltransferases (PRMT) has been shown to be upregulated in various cancers. PRMTs have emerged as attractive targets for the development of new cancer therapies.

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CARM1 is a protein arginine methyltransferase (PRMT) that acts as a coactivator in a number of transcriptional programs. CARM1 orchestrates this coactivator activity in part by depositing the H3R17me2a histone mark in the vicinity of gene promoters that it regulates. However, the gross levels of H3R17me2a in CARM1 KO mice did not significantly decrease, indicating that other PRMT(s) may compensate for this loss.

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Introduction: In the last decade, a number of genomic and pharmacological studies have demonstrated the importance of epigenetic dysregulation in medulloblastoma initiation and progression. High throughput approaches including gene expression array, next-generation sequencing (NGS), and methylation profiling have now clearly identified at least four molecular subgroups within medulloblastoma, each with distinct clinical and prognostic characteristics. These studies have clearly shown that despite the overall paucity of mutations, clinically relevant events do occur within the cellular epigenetic machinery.

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Somatic mutations affecting CREBBP and EP300 are a hallmark of diffuse large B-cell lymphoma (DLBCL). These mutations are frequently monoallelic, within the histone acetyltransferase (HAT) domain and usually mutually exclusive, suggesting that they might affect a common pathway, and their residual WT expression is required for cell survival. Using in vitro and in vivo models, we found that inhibition of CARM1 activity (CARM1i) slows DLBCL growth, and that the levels of sensitivity are positively correlated with the CREBBP/EP300 mutation load.

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The coactivator-associated arginine methyltransferase (CARM1) functions as a regulator of transcription by methylating a diverse array of substrates. To broaden our understanding of CARM1's mechanistic actions, we sought to identify additional substrates for this enzyme. To do this, we generated CARM1 substrate motif antibodies, and used immunoprecipitation coupled with mass spectrometry to identify cellular targets of CARM1, including mediator complex subunit 12 (MED12) and the lysine methyltransferase KMT2D.

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The discovery of inhibitors of methyl- and acetyl-binding domains has provided evidence for the 'druggability' of epigenetic effector molecules. The small-molecule probe UNC1215 prevents methyl-dependent protein-protein interactions by engaging the aromatic cage of MBT domains and, with lower affinity, Tudor domains. Using a library of tagged UNC1215 analogs, we screened a protein-domain microarray of human methyllysine effector molecules to rapidly detect compounds with new binding profiles with either increased or decreased specificity.

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Signal transduction in response to stimuli relies on the generation of cascades of posttranslational modifications that promote protein-protein interactions and facilitate the assembly of distinct signaling complexes. Arginine methylation is one such modification, which is catalyzed by a family of nine protein arginine methyltransferases, or PRMTs. Elucidating the substrate specificity of each PRMT will promote a better understanding of which signaling networks these enzymes contribute to.

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In many cells, mRNAs containing inverted repeated Alu elements (IRAlus) in their 3' untranslated regions (UTRs) are inefficiently exported to the cytoplasm. Such nuclear retention correlates with paraspeckle-associated protein complexes containing p54(nrb). However, nuclear retention of mRNAs containing IRAlus is variable, and how regulation of retention and export is achieved is poorly understood.

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Arginine methylation is a common post-translational modification that is crucial in modulating gene expression at multiple critical levels. The arginine methyltransferases (PRMTs) are envisaged as promising druggable targets, but their role in physiological and pathological pathways is far from being clear due to the limited number of modulators reported to date. In this effort, enzyme activators can be invaluable tools useful as gain-of-function reagents to interrogate the biological roles in cells and in vivo of PRMTs.

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Arginine methylation was discovered in the mid-1960s. About 15 years ago, the first protein arginine N-methyltransferase (PRMT) enzyme was described. The PRMT family now stands at nine members, and these enzymes play a key role in regulating a multitude of cellular events.

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Article Synopsis
  • CARM1 is a key target for hormone-related cancers, particularly prostate and breast cancers.
  • Research evaluated the effectiveness of certain compounds, specifically 1-benzyl-3,5-bis(3-bromo-4-hydroxybenzylidene)piperidin-4-one (7g) and its variations (8a-l), in inhibiting CARM1.
  • Compounds 7g, 8e, and 8l were found to inhibit CARM1 effectively while showing limited effects on other related enzymes, and 7g significantly reduced PSA promoter activity in LNCaP cells.
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Arginine methylation is a common post-translational modification that has been strongly implicated in transcriptional regulation. The arginine methyltransferases (PRMTs) were first reported as transcriptional coactivators for the estrogen and androgen receptors. Compounds that inhibit these enzymes will provide us with valuable tools for dissecting the roles of these enzymes in cells, and will possibly also have therapeutic applications.

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Here we report the synthesis of a number of compounds structurally related to arginine methyltransferase inhibitor 1 (AMI-1). The structural alterations that we made included: 1) the substitution of the sulfonic groups with the bioisosteric carboxylic groups; 2) the replacement of the ureidic function with a bis-amidic moiety; 3) the introduction of a N-containing basic moiety; and 4) the positional isomerization of the aminohydroxynaphthoic moiety. We have assessed the biological activity of these compounds against a panel of arginine methyltransferases (fungal RmtA, hPRMT1, hCARM1, hPRMT3, hPRMT6) and a lysine methyltransferase (SET7/9) using histone and nonhistone proteins as substrates.

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CARM1 is one of nine protein arginine methyltransferases that methylate arginine residues in proteins. CARM1 is recruited by many different transcription factors as a positive regulator. Gene targeting of CARM1 in mice has been performed, and knock-out mice, which are smaller than their wild-type littermates, die just after birth.

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A number of new compounds bearing two ortho-bromo- and ortho, ortho-dibromophenol moieties linked through a saturated/unsaturated, linear/(poly)cyclic spacer (compounds 1- 9) were prepared as simplified analogues of AMI-5 (eosin), a recently reported inhibitor of both protein arginine and histone lysine methyltransferases (PRMTs and HKMTs). Such compounds were tested against a panel of PRMTs (RmtA, PRMT1, and CARM1) and against human SET7 (a HKMT), using histone and nonhistone proteins as a substrate. They were also screened against HAT and SIRTs, because they are structurally related to some HAT and/or SIRT modulators.

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The coactivator-associated arginine methyltransferase 1 (CARM1) is recruited to gene promoters by many transcription factors. To identify new pathways that use CARM1, we carried out a comprehensive transcriptome analysis of CARM1-knockout embryos. By using complementary DNA microarrays and serial analysis of gene expression, we identified various genes involved in lipid metabolism that were underrepresented in CARM1-knockout embryos, indicating an important role for this coactivator in adipose tissue biology.

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Histone tail post-translational modification results in changes in cellular processes, either by generating or blocking docking sites for histone code readers or by altering the higher order chromatin structure. H3K4me3 is known to mark the promoter regions of active transcription. Proteins bind H3K4 in a methyl-dependent manner and aid in the recruitment of histone-remodeling enzymes and transcriptional cofactors.

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Human protein arginine methyltransferase PRMT8 has been recently described as a type I enzyme in brain that is localized to the plasma membrane by N-terminal myristoylation. The amino acid sequence of human PRMT8 is almost 80% identical to human PRMT1, the major protein arginine methyltransferase activity in mammalian cells. However, the activity of a recombinant PRMT8 GST fusion protein toward methyl-accepting substrates is much lower than that of a GST fusion of PRMT1.

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Article Synopsis
  • PRMT3 is a cytoplasmic type I arginine methyltransferase primarily associated with ribosomes through its interaction with the ribosomal protein rpS2, which it also methylates.
  • Mouse embryos lacking PRMT3 are smaller at birth but grow to a normal size as adults, showing similarities to Minute mutants.
  • While the absence of PRMT3 leads to hypomethylation of rpS2, the overall structure and levels of ribosome subunits and polyribosomes remain unchanged, suggesting that there are other specific proteins interacting with PRMT3 on the ribosomes.
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