ADAR1 regulates melanoma progression via miRNAs biogenesis
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ABSTRACT:
ORGANISM(S): synthetic construct Homo sapiens
PROVIDER: GSE31963 | GEO | 2012/08/31
SECONDARY ACCESSION(S): PRJNA144993
REPOSITORIES: GEO
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Project description:Aberrant RNA-editing was observed in several human tumors, but its significance is mostly unknown. Here we show that ADAR1, a ubiquitous RNA-editing enzyme, is commonly lost in metastatic melanoma cells and specimens. Experimental ADAR1 silencing significantly alters melanoma cell morphology, facilitates proliferation and cell-cycle, and increases the tumorigenicity in-vivo. A series of ADAR1 truncation mutants establishes a novel RNA-editing-independent role for ADAR1 in controlling the nuclear and cytoplasmic processing steps of miRNA biogenesis. Altered expression of ADAR1-controled miRNAs accounts for the observed phenotype. We show that the oncogenic miR-17-5p endogenously regulates ADAR1 expression and that its genomic sequence is frequently amplified in melanoma to overexpress the mature miR-17-5p form. ADAR1 and miR-17-5p are ubiquitously expressed, suggesting the generality of this mechanism. Melanoma cell line expressing low ADAR1 levels (ADAR1-Knockdown) using shRNA technique were selected for RNA extraction and hybridization on Affymetrix microarrays. We sought to examine the alterations in the genes and microRNA expression profile in the manipulated cell system, due to ADAR1 possible involvement cancer development. To that end, we selected ADAR1-knockdown (ADAR1-KD) cells that demonstrated an enhanced aggressive phenotype both in vivo and in vitro as compared to the control cells (Control).
2012-08-31 | E-GEOD-31963 | biostudies-arrayexpress
Project description:The blossom of immunotherapy in melanoma highlights the need to delineate mechanisms of immune resistance. Recently, we have demonstrated that the RNA editing protein, adenosine deaminase acting on RNA-1 (ADAR1) is down-regulated during metastatic transition of melanoma, which enhances melanoma cell proliferation and tumorigenicity. Here we investigate the role of ADAR1 in melanoma immune resistance. Importantly, knockdown of ADAR1 in human melanoma cells induces resistance to tumor infiltrating lymphocytes in a cell contact-dependent mechanism. We show that ADAR1, in an editing-independent manner, regulates the biogenesis of miR-222 at the transcription level and thereby Intercellular Adhesion Molecule 1 (ICAM1) expression, which consequently affects melanoma immune resistance. ADAR1 thus has a novel, pivotal, role in cancer immune resistance. Corroborating with these results, the expression of miR-222 in melanoma tissue specimens was significantly higher in patients who had no clinical benefit from treatment with ipilimumab as compared to patients that responded clinically, suggesting that miR-222 could function as a biomarker for the prediction of response to ipilimumab. These results provide not only novel insights on melanoma immune resistance, but also pave the way to the development of innovative personalized tools to enable optimal drug selection and treatment. 13 formalin fixed paraffin embedded (FFPE) melanoma tissues were stained with hematoxilin and eosin for examination by an expert pathologist. Non-tumor tissue was removed. Total RNA was isolated using miRNeasy FFPE kit (Qiagen) according to the manufacture guidelines.
2015-12-31 | E-GEOD-67496 | biostudies-arrayexpress
Project description:The blossom of immunotherapy in melanoma highlights the need to delineate mechanisms of immune resistance. Recently, we have demonstrated that the RNA editing protein, adenosine deaminase acting on RNA-1 (ADAR1) is down-regulated during metastatic transition of melanoma, which enhances melanoma cell proliferation and tumorigenicity. Here we investigate the role of ADAR1 in melanoma immune resistance. Importantly, knockdown of ADAR1 in human melanoma cells induces resistance to tumor infiltrating lymphocytes in a cell contact-dependent mechanism. We show that ADAR1, in an editing-independent manner, regulates the biogenesis of miR-222 at the transcription level and thereby Intercellular Adhesion Molecule 1 (ICAM1) expression, which consequently affects melanoma immune resistance. ADAR1 thus has a novel, pivotal, role in cancer immune resistance. Corroborating with these results, the expression of miR-222 in melanoma tissue specimens was significantly higher in patients who had no clinical benefit from treatment with ipilimumab as compared to patients that responded clinically, suggesting that miR-222 could function as a biomarker for the prediction of response to ipilimumab. These results provide not only novel insights on melanoma immune resistance, but also pave the way to the development of innovative personalized tools to enable optimal drug selection and treatment.
2015-12-31 | GSE67496 | GEO
Project description:The ADAR RNA editing enzymes deaminate adenosine bases to inosines in cellular RNAs, recoding open reading frames. Human ADAR1 mutations cause Aicardi-Goutieres Syndrome (AGS) and Adar1 mutant mice showing an aberrant interferon response and death by embryonic day E12.5 model the human disease. Searches have not identified key ADAR1 RNA editing sites recoding immune/haematopoietic proteins but editing is widespread in Alu sequences. We show that Adar1 embryonic lethality is rescued in Adar1; Mavs double mutant mice in which general antiviral responses to cytoplasmic dsRNA are prevented. We propose that inosine bases are epigenetic marks identifying cellular RNA as innate immune ÒselfÓ. Consistent with this idea we show that an editing-active cytoplasmic ADAR is required to prevent aberrant immune responses in Adar1 mutant mouse embryo fibroblasts. No dramatic increase in repetitive transcripts is observed. AGS mutations in ADAR1 affect editing by the interferon-inducible cytoplasmic ADAR1 isoform. RNA-seq expression profiling in Adar1 and Adar1/Mavs knockout mice embryos.
2014-12-19 | E-GEOD-62917 | biostudies-arrayexpress
Project description:RNAseq analysis of cell lines with ADAR1-p150 and ADAR1-p110 knock-outs and primary human tissue samples (from GSE57353 and GSE99392 data sets) to identify sites of ADAR1 editing
2018-12-04 | GSE115127 | GEO
Project description:The various roles of microRNAs (miRNAs) in controlling the phenotype of cancer cells are the focus of contemporary research efforts. We have recently shown that miR-17 directly targets the ADAR1 gene and thereby enhances melanoma cell aggressiveness. miR-17 and miR-20a belong to the miR-17/92 complex, and their mature forms are identical except for two non-seed nucleotides. Nevertheless, here we show that these two miRNAs carry markedly different effects on melanoma cells. A strong positive correlation was observed between the expression of miR-17 and miR-20a among various melanoma cultures. Luciferase assays showed that miR-17 but not miR-20a directly targets the 3' untranslated region of the ADAR1 gene. Ectopic expression of these miRNAs in melanoma cells differentially alters the expression of five exemplar TargetScan-predicted target genes ADAR1, ITGB8, TGFBR2, MMP2 and VEGF-A. Whole genome expression microarrays confirm a markedly differential effect on the transcriptome. Functionally, over-expression of miR-20a but not of miR-17 in melanoma cells inhibits net proliferation in-vitro. The differential functional effect was observed following ectopic expression of the mature miRNA or of the pre-miRNA sequences. This suggests that the two non-seed nucleotides dictate target sequence recognition and overall functional relevance. These miRNAs are clearly not redundant in melanoma cell biology.
2014-12-31 | GSE57158 | GEO
Project description:ADAR1 is an interferon (IFN) inducible RNA editing enzyme that converts adenosine (A) to inosine (I). Here we identified ADAR1 and ADAR1p150 specific editing events by conducting RNA-seq on WT, ADAR1 KO, and ADAR1p150 KO cells.
2018-02-09 | GSE99249 | GEO
Project description:The project aims to evaluate the contribution of ADAR1 RNA editing to B cell lymphomagenesis, specifically in diffuse large B cell lymphoma (DLBCL). Within our DLBCL cohort, RNA editing targets transcripts within known lymphoma-driving pathways such as apoptosis, p53 and NF-kB signaling, as well as the previously unrecognized RIG-I-like pathway. In the latter context, we show that ADAR1-mediated editing in the MAVS transcript correlates with increased MAVS protein expression levels, associating with increased interferon/NF-kB signaling and increased T cell exhaustion. To confirm this mechanism, we have performed LC-MSMS analysis on a DLBCL cell line (RCK8) in the presence or absence of ADAR1 (Figure S11D ). Additionally, using targeted RNA base editing tools to restore editing within MAVS 3'UTR in ADAR1-deficient cells, we demonstrate that editing is likely to be causal to an increase in downstream signaling in the absence of activation by canonical nucleic acid receptor sensing. To confirm that this signaling increase depends on an increase of MAVS protein upon specific editing, we have performed LC-MSMS analysis on the same samples (Figure 4G).
2023-07-20 | PXD041549 | Pride
Project description:Purpose: RNA editing by ADAR1 is essential for hematopoietic development. The goals of this study were firstly, to identify ADAR1-specific RNA-editing sites by indentifying A-to-I (G) RNA editing sites in wild type mice that were not edited or reduced in editing frequency in ADAR1 deficient murine erythroid cells. Secondly, to determine the transcription consequence of an absence of ADAR1-mediated A-to-I editing. Methods: Total RNA from E14.5 fetal liver of embryos with an erythroid restricted deletion of ADAR1 (KO) and littermate controls (WT), in duplicate. cDNA libraries were prepared and RNA sequenced using Illumina HiSeq2000. The sequence reads that passed quality filters were analyzed at the transcript level with TopHat followed by Cufflinks. qRTâPCR validation was performed using SYBR Green assays. A-to-I (G) RNA editing sites were identified as previously described by Ramaswami G. et al., Nature Methods, 2012 using BurrowsâWheeler Aligner (BWA) followed by ANOVA (ANOVA). RNA editing sites were confirmed by Sanger sequencing. Results: Using an optimized data analysis workflow, we mapped about 30 million sequence reads per sample to the mouse genome (build mm9) and identified 14,484 transcripts in the fetal livers of WT and ADAR1E861A mice with BWA. RNA-seq data had a goodness of fit (R2) of >0.7, p<0.0001 between biological duplicates per genotype. Clusters of hyper-editing were onserved in long, unannotated 3'UTRs of erythroid specific transcripts. A profound upregulation of interferon stimulated genes were found to be massively upregulated (up to 5 log2FC) in KO fetal liver compared to WT. 11.332 (6,894 novel) A-to-I RNA editing sites were identified when assessing mismatches in RNA-seq data. Conclusions: Our study represents the first detailed analysis of erythroid transcriptomes and A-to-I RNA editing sites, with biologic replicates, generated by RNA-seq technology. A-to-I RNA editing is the essential function of ADAR1 and is required to prevent sensing of endogenous transcripts, likely via a RIG-I like receptor mediated axis. Fetal liver mRNA profiles of E14.5 wild type (WT) and ADAR Epor-Cre knock out mice were generated by deep sequencing, in duplicate using Illumina HiSeq 2000.
2016-07-24 | E-GEOD-71042 | biostudies-arrayexpress
Project description:ADAR1-mediated RNA editing suppresses the immunostimulatory potential of endogenous RNA. Deficiency in ADAR1 triggers inflammatory responses; however, the underlying mechanisms remain unclear. In this study, we overexpressed wild-type ADAR1 (ADAR1 WT) and various disease-associated ADAR1 variants in 293T cells to examine transcriptomic RNA editing events. We further compared how disease-associated ADAR1 variants fail to edit specific RNA substrates, potentially contributing to the activation of inflammatory pathways.
2025-03-31 | GSE285023 | GEO