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EZH2 inhibition in multiple myeloma downregulates myeloma associated oncogenes and upregulates microRNAs with potential tumor suppressor functions.
Cell line
View SamplesMultiple Myeloma (MM) is a plasma cell tumor localized to the bone marrow (BM). Despite current progress in improving patient outcome, MM remains largely incurable. Disease clonal and interpatient heterogeneity has hampered identification of a common underlying mechanism for disease establishment and have slowed the development of novel targeted therapies. Epigenetic aberrations are now emerging as increasingly important in tumorigenesis, thus selective targeting of crucial epigenetic enzymes may provide new therapeutic potential in cancer including MM. Recently, we and others suggested the histone methyltransferase enhancer of zeste homolog 2 (EZH2), to be a potential therapeutic target in MM. Now we show that pharmacological inhibition of EZH2 suppresses the MM cell growth through downregulation of MM-associated oncogenes; IRF-4, XBP-1, PRDM1/BLIMP-1and c-MYC. We also show that downregulation of these genes is mediated via reactivated expression of microRNAs with tumor suppressor functions; primarily miR125a-3p and miR320c. Using chromatin immunoprecipitation (ChIP) we demonstrate that miR125a-3p and miR320c are targets of EZH2 and H3K27me3 in MM cell lines and primary MM cells. Our results further highlight the importance of polycomb-mediated silencing in MM to include microRNAs with tumor suppressor activity. This novel role further strengthens the oncogenic features of EZH2 and its potential as a therapeutic target in MM.
EZH2 inhibition in multiple myeloma downregulates myeloma associated oncogenes and upregulates microRNAs with potential tumor suppressor functions.
Cell line
View SamplesPublished molecular profiling studies in patients with lymphoma suggested the influence of hypoxia inducible factor-1 alpha (HIF1) targets in prognosis of DLBCL. Yet, the role of hypoxia in hematological malignancies remains unclear. We observed that activation of HIF1 resulted in global translation repression during hypoxic stress in DLBCL. Protein translation efficiency as measured using 35S-labeled methionine incorporation revealed a 50% reduction in translation upon activation of HIF1. Importantly, translation was not completely inhibited and expression of clinically correlated hypoxia targets such as GLUT1, HK2, and CYT-C was found to be refractory to translational repression under hypoxia in DLBCL cells. Notably, hypoxic induction of these genes was not observed in normal primary B-cells. Translational repression was coupled with a decrease in mitochondrial function. Screening of primary DLBCL patient samples revealed that expression of HK2, which encodes for the enzyme hexokinase 2, was significantly correlated with DLBCL phenotype. Genetic knockdown studies demonstrated that HK2 is required for promoting growth of DLBCL under hypoxic stress. Altogether, our findings provide strong support for the direct contribution of HK2 in B-cell lymphoma development and suggest that HK2 is a key metabolic driver of the DLBCL phenotype.ne incorporation revealed a 50% reduction in translation upon activation of HIF1. Importantly, translation was not completely blunted and expression of clinically correlated hypoxia targets such as GLUT1, HK2, and CYT-C was found to be refractory to translational repression under hypoxia in DLBCL cells. Notably, hypoxic induction of these genes was not observed in normal primary B-cells. Translational repression was coupled with decrease in mitochondrial function. Screening of DLBCL patient samples identified that expression of HK2, which encodes for the enzyme hexokinase 2, was significantly correlated with DLBCL phenotype. Genetic knockdown studies show that HK2 is required for promoting growth of DLBCL under hypoxic stress. Altogether, our findings provide more definitive proof of direct contribution of HK2 in development of B-cell lymphoma and suggest that HK2 is a key metabolic driver of DLBCL phenotype.
Role of hypoxia in Diffuse Large B-cell Lymphoma: Metabolic repression and selective translation of HK2 facilitates development of DLBCL.
Cell line, Treatment
View SamplesTo understand the biological mechanism of ELL2 in multiple myeloma (MM), we show that the MM risk allele lowers ELL2 expression in CD138+ plasma cells (Pcombined=2.5×10-27; bcombined=-0.24 s.d.), but not in peripheral blood or other tissues. Consistent with this, several variants representing the MM risk allele map to regulatory genomic regions, and three yield reduced transcriptional activity in plasmocytoma cell lines. One of these (rs3777189-C) co-locates with the best-supported lead variants for ELL2 expression and MM risk, and reduces binding of MAFF/G/K family transcription factors. Moreover, further analysis reveals that the MM risk allele associates with upregulation of gene sets related to ribosome biogenesis, and knockout/knockdown and rescue experiments in plasmocytoma cell lines support a cause-effect relationship. Overall design: Reconstitution of ELL2 expression in L363-ELL2-knockout cells
The multiple myeloma risk allele at 5q15 lowers ELL2 expression and increases ribosomal gene expression.
Specimen part, Disease, Disease stage, Cell line, Treatment, Subject
View SamplesTo understand the biological mechanism of ELL2 in multiple myeloma (MM), we show that the MM risk allele lowers ELL2 expression in CD138+ plasma cells (Pcombined=2.5×10-27; bcombined=-0.24 s.d.), but not in peripheral blood or other tissues. Consistent with this, several variants representing the MM risk allele map to regulatory genomic regions, and three yield reduced transcriptional activity in plasmocytoma cell lines. One of these (rs3777189-C) co-locates with the best-supported lead variants for ELL2 expression and MM risk, and reduces binding of MAFF/G/K family transcription factors. Moreover, further analysis reveals that the MM risk allele associates with upregulation of gene sets related to ribosome biogenesis, and knockout/knockdown and rescue experiments in plasmocytoma cell lines support a cause-effect relationship. Overall design: knock out ELL2 in L363 cells using CRISPR-Cas9
The multiple myeloma risk allele at 5q15 lowers ELL2 expression and increases ribosomal gene expression.
Disease, Disease stage, Cell line, Subject
View SamplesMammalian interphase chromosomes interact with the nuclear lamina (NL) through hundreds of large Lamina Associated Domains (LADs). We report a method to map NL contacts genome-wide in single human cells. Analysis of ~400 maps reveals a core architecture of gene-poor LADs that contact the NL with high cell-to-cell consistency, interspersed by LADs with more variable NL interactions. The variable contacts are more sensitive to a change in genome ploidy than the consistent contacts. Single-cell maps indicate that NL contacts involve multivalent interactions over hundreds of kilobases. Moreover, we observe extensive intra-chromosomal coordination of NL contacts, even over tens of megabases. Such coordinated loci exhibit preferential interactions as detected by Hi-C. Finally, single-cell gene expression and chromatin accessibility analysis shows that loci with consistent NL contacts are expressed at lower levels and are more consistently inaccessible than loci with lower contact frequencies. These results highlight fundamental principles of single cell chromatin organization. Overall design: In this dataset, single-cell mRNA sequencing results from 96 single KBM7 cells have been deposited
Genome-wide maps of nuclear lamina interactions in single human cells.
No sample metadata fields
View SamplesAs exposure to episodic drought can impinge significantly on forest health and the establishment of productive tree plantations, there is great interest in understanding the mechanisms of drought response in trees. The ecologically dominant and economically important genus Populus, with its sequenced genome, provides an ideal opportunity to examine transcriptome level changes in trees in response to a drought stimulus. The transcriptome level drought response of two commercially important hybrid Populus clones (P. deltoides P. nigra, DN34, and P. nigra P. maximowiczii, NM6) was characterized over a diurnal period using a 4 2 2 completely randomized factorial ANOVA experimental design (four time points, two genotypes, and two treatment conditions) using Affymetrix Poplar GeneChip microarrays. Notably, the specific genes that exhibited changes in transcript abundance in response to drought differed between the genotypes and/or the time of day that they exhibited their greatest differences. This study emphasizes the fact that it is not possible to draw simple, generalized conclusions about the drought response of the genus Populus on the basis of one species, nor on the basis of results collected at a single time point. The data derived from our studies provide insights into the variety of genetic mechanisms underpinning the Populus drought response, and provide candidates for future experiments aimed at understanding this response across this economically and ecologically important genus.
Genotype and time of day shape the Populus drought response.
Age, Specimen part, Treatment
View SamplesTo screen for specific circadian outputs that may distinguish the pacemaker in the mammalian suprachiasmatic nucleus (SCN) from peripheral-type oscillators in which the canonical clockworks are similarly regulated in a circadian manner, the rhythmic behavior of the transcriptome in forskolin-stimulated NIH/3T3 fibroblasts was analyzed and compared to that found in the rat SCN in vivo and SCN2.2 cells in vitro. Similar to the scope of circadian gene expression in SCN2.2 cells and the rat SCN, NIH/3T3 fibroblasts exhibited circadian fluctuations in the expression of the core clock genes, Per2, Bmal1 (Mop3), and Cry1 and 323 functionally diverse transcripts (2.6%), many of which were involved in cell communication. Overlap in rhythmically-expressed transcripts among NIH/3T3 fibroblasts, SCN2.2 cells and the rat SCN was limited to these clock genes and four other genes that mediate fatty acid and lipid metabolism or function as nuclear factors. Compared to NIH/3T3 cells, circadian gene expression in SCN oscillators was more prevalent among cellular pathways mediating glucose metabolism and neurotransmission. Coupled with evidence for the rhythmic regulation of the inducible isoform of nitric oxide synthase, the enzyme responsible for the production of nitric oxide, in SCN2.2 cells and the rat SCN but not in fibroblasts, studies examining the effects of a NOS inhibitor on metabolic rhythms in co-cultures containing SCN2.2 cells and untreated NIH/3T3 cells suggest that this gaseous neurotransmitter may play a key role in SCN pacemaker function. Thus, this comparative analysis of circadian gene expression in SCN and non-SCN cells may have important implications in the selective identification of circadian signals involved in the coupling of SCN oscillators and the regulation of rhythmicity in downstream cells or tissues.
Circadian profiling of the transcriptome in NIH/3T3 fibroblasts: comparison with rhythmic gene expression in SCN2.2 cells and the rat SCN.
No sample metadata fields
View SamplesThe capacity of embryonic stem cells to differentiate into all lineages of mature organism is precisely regulated by cellular signaling factors. STAT3 is a crucial transcription factor that plays a central role in maintaining embryonic stem cells identity. However the underlying mechanism how Stat3 directs differentiation is still not completely understood. Here we show that Stat3 positively regulates gene expression of methyltransferase like protein 8 (Mettl8) in mouse ES cells. We found that Mettl8 is dispensable for pluripotency but affects ESCs differentiation. Subsequently we discovered that Mettl8 interacts with Mapkbp1's mRNA, which is an intermediate factor in JNK signaling, and inhibits the translation of the mRNA. Thereby, Mettl8 prohibits the activation of JNK signaling and enhances the differentiation of mouse ESCs. Collectively, our study uncovers a Stat3 target Mettl8 which regulates mouse ESCs differentiation via JNK signaling. Overall design: mRNA profiles of E14 cells transfected with scramble siRNA or Mettl8 siRNA were generated by deep sequencing, in triplicate, using Illumina GAIIx.
The STAT3 Target Mettl8 Regulates Mouse ESC Differentiation via Inhibiting the JNK Pathway.
Specimen part, Cell line, Subject
View SamplesThe use of radiation treatment has increased for both sporadic and neurofibromatosis type 2 (NF2)-associated vestibular schwannoma (VS). However, there are a subset of radioresistant tumors and systemic treatments that are seldom used in these patients. We investigated molecular alterations after radiation in three NF2-associated and five sporadically operated recurrent VS after primary irradiation. We compared these findings with 49 non-irradiated (36 sporadic and 13 NF2-associated) VS through gene-expression profiling and pathway analysis. Furthermore, we stained the key molecules of the distinct pathway by immunohistochemistry. A total of 195 differentially expressed genes in sporadic and NF2-related comparisons showed significant differences based on the criteria of p value < 0.05 and a two-fold change. These genes were involved in pathways that are known to be altered upon irradiation (e.g., mammalian target of rapamycin (mTOR), phosphatase and tensin homolog (PTEN) and vascular endothelial growth factor (VEGF) signaling). We observed a combined downregulation of PTEN signaling and an upregulation of mTOR signaling in progressive NF2-associated VS after irradiation. Immunostainings with mTOR and PTEN antibodies confirmed the respective molecular alterations. Taken together, mTOR inhibition might be a promising therapeutic strategy in NF2-associated VS progress after irradiation.
Contribution of mTOR and PTEN to Radioresistance in Sporadic and NF2-Associated Vestibular Schwannomas: A Microarray and Pathway Analysis.
Specimen part, Disease
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