5-Fluorouracil (5-FU) is a widely used chemotherapeutic drug in colorectal cancer. Previous studies showed that 5-FU modulates RNA metabolism and mRNA expression. In addition, it has been reported that 5-FU incorporates into the RNAs constituting the translational machinery and that 5-FU affects the amount of some mRNAs associated with ribosomes. However, the impact of 5-FU on translational regulation remains unclear. Using translatome profiling, we report that a clinically relevant dose of 5-FU induces a translational reprogramming in colorectal cancer cell lines. Comparison of mRNA distribution between polysomal and non-polysomal fractions in response to 5-FU treatment using microarray quantification identified 313 genes whose translation was selectively regulated. These regulations were mostly stimulatory (91%). Among these genes, we showed that 5-FU increases the mRNA translation of HIVEP2, which encodes a transcription factor whose translation in normal condition is known to be inhibited by mir-155. In response to 5-FU, the expression of mir-155 decreases thus stimulating the translation of HIVEP2 mRNA. Interestingly, the 5-FU-induced increase in specific mRNA translation was associated with reduction of global protein synthesis. Altogether, these findings indicate that 5-FU promotes a translational reprogramming leading to the increased translation of a subset of mRNAs that involves at least for some of them, miRNA-dependent mechanisms. This study supports a still poorly evaluated role of translational control in drug response.
Translational reprogramming of colorectal cancer cells induced by 5-fluorouracil through a miRNA-dependent mechanism.
Treatment
View SamplesNeuroblastoma cell lines can differentiate upon retinoic acid (RA) treatment, a finding that provided the basis for the clinical use of RA to treat neuroblastoma. However, resistance to RA is often observed, which limits its clinical utility. Using a gain-of-function genetic screen we identify the transcriptional coactivator Mastermind-like 3 (MAML3) as a gene whose ectopic expression confers resistance to RA. We find that MAML3 expression leads to loss of activation of a subset of RA target genes, which hampers RA-induced differentiation. The regulatory DNA elements of this subset of RA target genes show overlap in binding of MAML3 and the retinoic acid receptor, suggesting a role for MAML3 in the regulation of these genes. In addition, MAML3 has RA independent functions, including the activation of IGF1R and downstream AKT signaling via upregulation of IGF2, resulting in increased proliferation. Our results indicate an important role for MAML3 in differentiation and proliferation of neuroblastomas. Overall design: RNA-seq of SK-N-SH control and MAML3 overexpressing (SD3.23) cells, either untreated (UT) or treated with 1 µM RA (RA).
Mastermind-Like 3 Controls Proliferation and Differentiation in Neuroblastoma.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Using gene expression to predict differences in the secretome of human omental vs. subcutaneous adipose tissue.
Sex, Specimen part
View SamplesThe objective was to characterize differences in the secretome of human omental compared with subcutaneous adipose tissue using global gene expression profiling. Gene expression was measured using Affymetrix microarrays in subcutaneous and omental adipose tissue (n=3 independent subjects; 6 arrays). Predictive bioinformatic algorithms were employed to identify those differentially expressed genes that code for secreted proteins and to identify common pathways between these proteins. All patients provided informed written consent before inclusion in the study which was approved by the North of Scotland Research Ethics Committee (NOSREC).
Using gene expression to predict differences in the secretome of human omental vs. subcutaneous adipose tissue.
Sex, Specimen part
View SamplesSTAT5A and STAT5B proteins belong to the family of signal transducers and activators of transcription. They are encoded by 2 separate genes with 91% identity in their amino acid sequences. Despite their high degree of conservation, STAT5A and STAT5B exert non-redundant functions, resulting at least in part from differences in target gene activation. To better characterize the differential contribution of STAT5A and STAT5B in gene regulation, we performed single or double knock-down of STAT5A and STAT5B using small interfering RNA. Subsequent gene expression profiling and RT-qPCR analyses of IL-3-stimulated Ba/F3-beta cells led to the identification of putative novel STAT5 target genes. Chromatin immunoprecipitation assays analyzing the corresponding gene loci identified unusual STAT5 binding sites compared to conventional STAT5 responsive elements. Some of the STAT5 targets identified are upregulated in several human cancers, suggesting that they might represent potential oncogenes in STAT5-associated malignancies.
In vivo identification of novel STAT5 target genes.
No sample metadata fields
View SamplesSox2 is required to maintain osteosarcoma cell tumor initiation.Knockdown of Sox2 leads tpo loss of tumorigenic properties. To examine gene expression changes upon Sox2 knockdown, we performed microarray analysis on mouse osteosarcoma cells expressing scrambled or Sox2shRNA. We found that genes upregulated upon Sox2 knockdown included osteoblast diffrentiation genes and genes down regulated included cell cycle and RNA processing genes as well as YAP-TEAD target genes.
Sox2 antagonizes the Hippo pathway to maintain stemness in cancer cells.
Specimen part, Cell line
View SamplesThe Mediator complex regulates gene transcription by linking basal transcriptional machinery with DNA-bound transcription factors. The activity of the Mediator complex is mainly controlled by a kinase submodule that is comprised of four proteins, including MED12. Although ubiquitously expressed, Mediator subunits can differentially regulate gene expression in a tissue-specific manner. Here, we report that MED12 is required for normal cardiac function such that mice with conditional cardiac-specific deletion of MED12 display progressive dilated cardiomyopathy. Loss of MED12 perturbs expression of calcium handling genes in the heart, consequently altering calcium cycling in cardiomyocytes and disrupting cardiac electrical activity. We identified transcription factors that regulate expression of calcium-handling genes that are downregulated in the heart in the absence of MED12, and found that MED12 localizes to transcription factor consensus sequences within calcium handling genes. We showed that MED12 interacts with one such transcription factor, MEF2, in cardiomyocytes, and that MED12 and MEF2 co-occupy promoters of calcium handling genes. Furthermore, we demonstrated that MED12 enhances MEF2 transcriptional activity and overexpression of both increases expression of calcium handling genes in cardiomyocytes. Our data support a role for MED12 as a coordinator of transcription through MEF2 and other transcription factors. We conclude that MED12 is a regulator of a network of calcium handling genes, consequently “mediating” contractility in the mammalian heart. Overall design: Ventricle mRNA profiles of 1-day old control (CTL, CreNEG) and cardiac-specific Med12 knockout mice (Med12cKO, CrePOS) were generated by deep sequencing, in triplicate, using Illumina.
MED12 regulates a transcriptional network of calcium-handling genes in the heart.
No sample metadata fields
View SamplesTranscriptomic analysis of primary human umbilical vein endothelial cells (HUVEC). HUVEC were treated in vitro with CoCl2 to induce hypoxia, high glucose and high glucose plus hypoxia in different intervals (1, 3, 12 hours). Subsequently, the effect of metformin (anti-diabetic drug) on all conditions was studied to take advantage of transcriptomics to prospectively explore the mechanism of this drug to reduce the risk of cardiovascular diseases in type II diabetic patients.
Reference genes for expression studies in hypoxia and hyperglycemia models in human umbilical vein endothelial cells.
Specimen part
View SamplesIntroduction: Glioma stem cells isolated from human glioblastomas are resistant to radiation and cytotoxic chemotherapy and may drive tumor recurrence. Treatment efficacy may depend on the presence of glioma stem cells, expression of DNA repair enzymes such as methylguanine methyltransferase (MGMT), or transcriptome subtype. Methods: To model genetic alterations in the core signaling pathways of human glioblastoma, we induced conditional Rb knockout, Kras activation, and Pten deletion mutations in cortical murine astrocytes. Serial neurosphere culture, multi-lineage differentiation, and orthotopic transplantation were used to assess whether these mutations induced de-differentiation of cortical astrocytes into glioma stem cells. Efficacy of radiation and temozolomide was examined in vitro and in an allograft model in vivo. The effects of radiation on transcriptome subtype was examined by expression profiling. Results: G1/S-defective, Rb knockout astrocytes gained unlimited self-renewal and multi-lineage differentiation capacity, in both the presence and absence of Kras and Pten mutations. Only triple mutant astrocytes formed serially-transplantable glioblastoma allografts. Triple mutant astrocytes and allografts were sensitive to radiation, but expressed Mgmt and were resistant to temozolomide. Radiation induced a shift in transcriptome subtype of glioblastoma allografts from proneural to mesenchymal. Conclusion: A defined set of core signaling pathway mutations induces de-differentiation of cortical murine astrocytes into glioma stem cells. This non-germline genetically engineered mouse model mimics human proneural glioblastoma on histopathological, molecular, and treatment response levels. It may be useful in dissecting the genetic and cellular mechanisms of treatment resistance and developing more effective therapies. Overall design: Investigation of chromatin accessibility in astrocytes and glioblastoma cell lines
Core pathway mutations induce de-differentiation of murine astrocytes into glioblastoma stem cells that are sensitive to radiation but resistant to temozolomide.
Cell line, Subject
View SamplesAnaplastic large-cell lymphoma (ALCL) makes up approximately 15% of paediatric non-Hodgkin's lymphomas of childhood. The vast majority of them is associated with the t(2;5)(p23;q35) translocation that results in the expression of a hybrid oncogenic tyrosine kinase, NPM-ALK. In order to investigate ALCL biological characteristics we used transcriptional profiling approach. Genome-wide gene expression profiling, performed on 23 paediatric ALCL and 12 reactive lymph nodes specimens, showed two novel ALCL subgroups based on their NPM-ALK expression levels (named (ALK low and ALK high). Gene set enrichment analysis revealed, in ALK low samples, a positive enrichment of genes involved in the Interleukin signaling pathway, whereas we found increased expression of genes related to cell cycle progression and division in ALK high tumour samples, such as Aurora Kinase A (AURKA) and B (AURKB). Growth inhibition was observed upon administration of AURKA and AURKB inhibitors Alisertib and Barasertib and it was associated with perturbation of the cell cycle and induction of apoptosis. In conclusion we identified two novel ALCL subgroups, which display unique biological characteristics suggesting sensitivity to distinct targeted therapies.
NPM-ALK expression levels identify two distinct subtypes of paediatric anaplastic large cell lymphoma.
No sample metadata fields
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