In an effort to understand the mechanisms of acquired resistance to BRAF inhibitors, we isolated clones that acquired resistance to the BRAF inhibitor GSK2118436 derived from the A375 BRAF V600E mutant melanoma cell line. This resistance clones acquired mutations in NRAS and MEK1. One clones, 16R6-4, acquired two mutations in NRAS Q61K and A146T. Proliferation and western blot analyses demonstrated that these clones were insensitive to single agent GSK2118436 or GSK1120212 (an allosteric MEK inhibitor) but were sensitive to the combination of GSK2118436 and GSK1120212. To further characterize this combination, global transcriptomic analysis was performed in A375 and 16R6-4 after 24 hour treatment with GSK2118436, GSK1120212 or the combination of GSK2118436 and GSK1120212.
Combinations of BRAF, MEK, and PI3K/mTOR inhibitors overcome acquired resistance to the BRAF inhibitor GSK2118436 dabrafenib, mediated by NRAS or MEK mutations.
Specimen part, Cell line, Treatment
View SamplesClinical symptoms of dengue virus (DENV) infection, the most prevalent arthropod-borne viral disease, range from classical mild dengue fever to severe, life-threatening dengue shock syndrome. However, most DENV infections cause few or no symptoms. Asymptomatic DENV-infected patients provide a unique opportunity to decipher the host immune responses leading to virus elimination without negative impact on an individuals health. We used an integrated approach of transcriptional profiling and immunological analysis to compare a Cambodian population of strictly asymptomatic viremic individuals with clinical dengue patients. Whereas inflammatory pathways and innate immune response pathways were similar between asymptomatic individuals and clinical dengue patients, expression of proteins related to antigen presentation and subsequent T and B cell activation pathways were differentially regulated, independent of viral load and previous DENV infection history. Feedback mechanisms controlled the immune response in asymptomatic viremic individuals, as demonstrated by increased activation of T cell apoptosis-related pathways and FcRIIB signaling associated with decreased anti-DENV specific antibody concentrations. Taken together, our data illustrate that symptom-free DENV infection in children is associated with determined by increased activation of the adaptive immune compartment and proper control mechanisms, leading to elimination of viral infection without excessive immune activation, with implications for novel vaccine development strategies
Increased adaptive immune responses and proper feedback regulation protect against clinical dengue.
Sex, Age, Specimen part, Disease, Disease stage
View SamplesTranslation and mRNA degradation are intimately connected, yet the mechanisms that regulate them are not fully understood. Here we examine the regulation of translation and mRNA stability in mouse embryonic stem cells (ESCs) and during differentiation. In contrast to previous reports, we found that transcriptional changes account for most of the molecular changes during ESC differentiation. Within ESCs translation level and mRNA stability are positively correlated. The RNA-binding protein DDX6 has been implicated in processes involving both translational repression and mRNA destabilization; in yeast DDX6 connects codon optimality and mRNA stability and in mammals DDX6 is involved in microRNA-mediated repression. We generated DDX6 KO ESCs and found that while there was minimal connection between codon usage and stability changes, the loss of DDX6 leads to the translational depression of microRNA targets. Surprisingly, the translational derepression of microRNA targets occurs without affecting mRNA stability. Furthermore, DDX6 KO ESCs share overlapping phenotypes and global molecular changes with ESCs that completely lack all microRNAs. Together our results demonstrate that the loss of DDX6 decouples the two forms of microRNA induced repression and emphasize that translational repression by microRNAs is underappreciated. Overall design: 4-thiouridine (4su) metabolic labeling was performed on mouse embryonic stem cells (ESCs) and Epiblast like cells (EpiLCs).
Decoupling the impact of microRNAs on translational repression versus RNA degradation in embryonic stem cells.
Specimen part, Disease, Subject
View SamplesDgcr8 and Dicer are both important components of the microRNA biogenesis pathway while Dicer is also implicated in biogenesis of other types of small RNAs such as siRNAs and mirtrons. Here we performed microarray analysis of WT, Dgcr8 and Dicer knockout ES cells to identify mRNAs differentially regulated upon loss of Dgcr8 and Dicer.
Genomic analysis suggests that mRNA destabilization by the microprocessor is specialized for the auto-regulation of Dgcr8.
Specimen part
View SamplesAbstract: Alternative splicing (AS) plays a major role in the generation of proteomic diversity and in gene regulation. However, the role of the basal splicing machinery in regulating AS remains poorly understood. Here we show that the core snRNP protein SmB/B’ self-regulates its expression by promoting the inclusion of a highly-conserved alternative exon in its own pre-mRNA that targets the spliced transcript for nonsense-mediated mRNA decay (NMD). Depletion of SmB/B’ in human cells results in reduced levels of snRNPs and in a striking reduction in the inclusion levels of hundreds of alternative exons, with comparatively few effects on constitutive exon splicing levels. The affected alternative exons are enriched in genes encoding RNA processing and other RNA binding factors, and a subset of these exons also regulate gene expression by activating NMD. Our results thus demonstrate a role for the core spliceosomal machinery in controlling an exon network that appears to modulate the levels of many RNA processing factors. Overall design: HeLa cells were transfected with a control non-targeting siRNA pool (siNT), or with siRNA pools designed to knockdown SmB/B'' or SRSF1 (also known as SF2/ASF/SFRS1). Sequence reads were aligned to exon-exon junction sequences in a database of EST/cDNA-mined cassette-type alternative splicing events. Processed data files (.bed and .txt) provided as supplementary files on the Series record. Processed data file build information: hg18.
Regulation of alternative splicing by the core spliceosomal machinery.
No sample metadata fields
View Sampleslet-7c and miR-294 were transfected into Dgcr8 -/- miRNA deficient ES cells and RNA was harvested after 12 hours
Opposing microRNA families regulate self-renewal in mouse embryonic stem cells.
Specimen part
View SamplesDicer, which is required for the processing of both microRNAs (miRNAs) and small interfering RNAs (siRNAs), is essential for oocyte maturation. Oocytes express both miRNAs and endogenous siRNAs (endo-siRNAs). To determine whether the abnormalities in Dicer knockout oocytes during meiotic maturation are secondary to the loss of endo-siRNAs and/or miRNAs, we deleted Dgcr8, which encodes a RNA binding protein specifically required for miRNA processing. In striking contrast to Dicer, Dgcr8 deficient oocytes matured normally and, when fertilized with wild-type sperm, produced healthy appearing offspring, even though miRNA levels were reduced to similar levels as Dicer deficient oocytes. Furthermore, the deletion of both maternal and zygotic Dgcr8 alleles did not impair preimplantation development including the determination of the inner cell mass (ICM) and trophectoderm. Most surprisingly, the mRNA profiles of wild-type and Dgcr8 null oocytes were essentially identical while Dicer null oocytes showed hundreds of misregulated transcripts. These findings show that miRNA function is globally suppressed during oocyte maturation and preimplantation development and that endo-siRNAs, rather than miRNAs, underlie the Dicer knockout phenotype in oocytes.
Opposing microRNA families regulate self-renewal in mouse embryonic stem cells.
Specimen part
View SamplesWe investigated the molecular mechanisms of chronic alcohol consumption or lipopolysaccharide insult by gene expression profiling in prefrontal cortex and liver of C57BL/6J mice.
Gene expression in brain and liver produced by three different regimens of alcohol consumption in mice: comparison with immune activation.
Age, Specimen part
View SamplesPeroxisome proliferator-activated receptors (PPARs) are nuclear hormone receptors that act as ligand-activated transcription factors. Although prescribed for dyslipidemia and type-II diabetes, PPAR agonists have demonstrated therapeutic properties for several brain disorders, including alcohol dependence. PPAR agonists decrease ethanol consumption and reduce withdrawal severity and susceptibility to stress-induced relapse in rodents. However, the cellular and molecular mechanisms facilitating these properties have yet to be investigated and little is known about their effects in the brain. We tested three PPAR agonists in a continuous access two-bottle choice (2BC) drinking paradigm and found that tesaglitazar and fenofibrate decreased ethanol consumption in male C57BL/6J mice while bezafibrate did not. Hypothesizing that fenofibrate and tesaglitazar are causing brain gene expression changes that precipitate the reduction in ethanol drinking, we gave daily oral injections of fenofibrate, tesaglitazar and bezafibrate to mice for eight consecutive days and collected liver, prefrontal cortex and amygdala 24 hours after last injection. RNA was isolated and purified using MagMAX-96 Total RNA Isolation Kit. Biotinylated, amplified cRNA was generated using Illumina TotalPrep RNA Amplification Kit and hybridized to Illumina MouseWG-6 v2.0 Expression microarrays.
PPAR agonists regulate brain gene expression: relationship to their effects on ethanol consumption.
Sex, Specimen part
View SamplesWe report on the regulation of transcripts following siRNA-mediated depletion of an RNA binding protein, CELF1, in primary chicken embryonic cardiomyocytes in culture. Overall design: Cultured chicken primary embryonic cardiomyocytes (isolated from embryonic day 8 hearts) were transfected with siRNA against CELF1 (n=3) or mock transfected (n=3) at 24 hours in culture.
Identification of Targets of CUG-BP, Elav-Like Family Member 1 (CELF1) Regulation in Embryonic Heart Muscle.
Specimen part, Treatment, Subject
View Samples