Differential gene expression in neuroblastoma cells after transfection with control siRNA, N-Myc siRNA-1, N-Myc siRNA-2, lncMycN siRNA-1 or lncMycN siRNA-2
Ontology highlight
ABSTRACT: N-Myc oncoprotein induces neuroblastoma by modulating gene transcription, and long noncoding RNAs exert biological effects by regulating gene expression. We analysed whether N-Myc and the long noncoding RNA lncMycN mediate the expression of common subsets of genes. Neuroblastoma Kelly cells were transfected with control siRNA, N-Myc siRNA-1, N-Myc siRNA-2, lncMycN siRNA-1 or lncMycN siRNA-2. RNA was extracted from the cells 48 hours after siRNA transfections, and subjected to differential gene expression studies with Affymetrix microarrays.
Project description:Efforts to therapeutically target EZH2 have generally focused on inhibition of its methyltransferase activity, although it remains less clear whether this is the central mechanism whereby EZH2 promotes cancer. We demonstrate that EZH2 directly interacts with both MYC family oncoproteins, MYC and MYCN, and promotes their stabilization in a methyltransferase-independent manner. By competing against the SCFFBW7 ubiquitin ligase to bind MYC and MYCN, EZH2 counteracted FBW7-mediated MYC(N) polyubiquitination and proteasomal degradation. Depletion, but not enzymatic inhibition, of EZH2 induced robust MYC(N) degradation and inhibited tumor cell growth in MYC(N) driven neuroblastoma and small cell lung cancer. These findings unveil the MYC family proteins as global EZH2 oncogenic effectors and EZH2 pharmacologic degraders as potential MYC(N) targeted cancer therapeutics, pointing out that MYC(N) driven cancers may develop inherent resistance to the canonical EZH2 enzymatic inhibitors currently in clinical development.
Project description:N-Myc oncoprotein induces neuroblastoma by modulating gene transcription, and long noncoding RNAs exert biological effects by regulating gene expression. We analysed whether N-Myc and the long noncoding RNA lncMycN mediate the expression of common subsets of genes.
Project description:Within the overall project, we performed a set of microarray and chromatin-immunoprecipitation (ChIP)-chip experiments using siRNA against the (pro)renin receptor ((P)RR), stable overexpression of PLZF, the PLZF translocation inhibitor genistein and the specific V-ATPase inhibitor bafilomycin to dissect transcriptional pathways downstream of the (P)RR. In this dataset, we include the expression data obtained from siRNA against (P)RR in KELLY cells.Three intervention samples and three control samples were analyzed. We generated the following pairwise comparisons using Chipinspector (Genomatix Software GmbH) and a FDR of 2%. ChipInspector carries out significance analysis on the single probe level. Normalized probe set level data not provided for individual Sample records. Processed data is available on Series record.
Project description:To identify c-myc target genes by siRNA transfection in a lymphoma cell line. Keywords: time series design OCI-Ly10 cells were transfected with c-myc siRNA pool versus control siRNA or buffer for a total of 4 microarrays.
Project description:Background: MYC is a transcription factor encoded by the c-MYC gene (thereafter termed MYC). MYC is key transcription factor involved in many central cellular processes including ribosomal biogenesis. MYC is overexpressed in the majority of human tumours including aggressive B-cell lymphoma especially Burkitt's lymphoma. Although Burkitt's lymphoma is a highlight example for MYC overexpression due to a chromosomal translocation, no global analysis of MYC binding sites by chromatin immunoprecipitation (ChIP) followed by global next generation sequencing (ChIP-Seq) has been conducted so far in Burkitt's lymphoma. Methodology/Principal Findings: ChIP-Seq was performed with a MYC-specific antibody giving rise to 7,054 predicted MYC binding sites after bioinformatics analysis of a total of 19 million sequence reads. In line with previous findings, binding sites accumulate in gene sets known to be involved in the ribosomal biogenesis, histone acetyltransferase and methyltransferase complexes and the cell cycle demonstrating a regulatory role of MYC in these processes. Unexpectedly, MYC binding sites also accumulate in genes typically expressed in mature B-cells. To assess the functional consequences of altered MYC binding, the ChIP-Seq data were supplemented with siRNA mediated knock-downs of MYC in BL cell lines followed by gene expression profiling. Interestingly, amongst others, genes involved in B-cell function were up-regulated in response to MYC silencing. Conclusion/Significance: The 7,054 MYC-binding sites identified by our ChIP-Seq approach greatly extend the knowledge regarding MYC binding in Burkitt's lymphoma and sheds further light on the enormous complexity of the MYC regulatory network. Especially our observation that (i) many B-cell relevant genes are targeted by MYC and (ii) that MYC down-regulation leads to an up-regulation of B-cell genes highlights an interesting aspect of BurkittM-BM-4s lymphoma biology. [ChIP-Seq] Analysis of MYC DNA binding sites by ChiP-Seq in 5 BurkittM-BM-4s lymphoma cell lines (Raji, Ramos, Blue1, BL41, CA46) [mRNA expression profiling] siRNA-mediated knock-down of MYC was done employing the BL cell lines Raji, BL41 and Blue1 in order to detect MYC-driven gene expression changes. For this purpose, the cells were Amaxa-transfected using MYC smart pool siRNA and control siRNA (Thermo Scientific/Dharmacon, Erembodegem, Belgium), respectively.
Project description:Epigenetic alterations appear to modulate Myc signaling. We investigated the role of the histone demethylase JMJD2B in Myc-mediated neuroblastoma pathogenesis. We demonstrate that Myc physically interacts with and recruits this epigenetic modifier, which removes repressive H3K9 methyl marks from Myc-target genes. JMJD2B regulates neuroblastoma proliferation and, together with MYCN amplification, identifies a subgroup of poor prognosis patients. We identify a novel histone demethylase inhibitor, ciclopirox, which targets JMJD2B and, consequently, Myc signaling, thereby inhibiting neuroblastoma proliferation and inducing differentiation. In xenograft studies, genetic and pharmacologic inhibition of JMJD2B resulted in significant tumor growth restriction. Our findings provide insight into epigenetic regulation of Myc via histone methylation and proof-of-concept for pharmacologic inhibition of histone demethylases to target Myc signaling in cancer. 8 samples were transfected with two different siRNAs for control, JMJD2B, MYCN and JARID1A.
Project description:WDR5 is an important co-factor for N-Myc-regulated transcriptional activation and tumorigenesis Using ChIP-Seq, We profiled key epigenetic marks H3K4 trimethylation in BE(2)-C neuroblastoma cells transfected with control siRNA or WDR5 siRNA-1 at N-Myc target gene promoters The results showed knockdown WDR5 significantly reduced H3K4me3 at 93.2% of N-Myc binding promoters, but only at 53.5% of N-Myc non-binding promoters. Identification of Histone H3K4 trimethylation and N-Myc binding sites in BE(2)-C cells transfected with control siRNA or WDR5 siRNA-1.
Project description:N-Myc oncoprotein induces neuroblastoma by modulating gene transcription, and long noncoding RNAs exert biological effects by regulating gene expression. We have found that one of long noncoding RNAs modulated by N-Myc is linc00467. We analysed the target genes of the long noncoding RNA linc00467 in neuroblastoma cells.
Project description:WDR5 is an important co-factor for N-Myc-regulated transcriptional activation and tumorigenesis We analysed whether WDR5 siRNAs modulate gene expression Neuroblastoma BE(2)-C cells were treated with control siRNA, WDR5 siRNA-1, and WDR5 siRNA-2 for 40 hours, and subjected to differential gene expression studies with Affymetrix microarrays.