Recent studies have shown that circular RNAs (circRNAs) are abundant, widely expressed in mammals, and can display cell-type specific expression. However, how production of circRNAs is regulated and their precise biological function remains largely unknown. To study how circRNAs might be regulated during colorectal cancer progression, we used three isogenic colon cancer cell lines that differ only in KRAS mutation status. Cellular RNAs from the parental DLD-1 cells that contain both wild-type and G13D mutant KRAS alleles and isogenically-matched derivative cell lines, DKO-1 (mutant KRAS allele only) and DKs-8 (wild-type KRAS allele only) were analyzed using RNA-Seq. We developed a bioinformatics pipeline to identify and evaluate circRNA candidates from RNA-Seq data. Hundreds of high-quality circRNA candidates were identified in each cell line. Remarkably, circRNAs were significantly down-regulated at a global level in DLD-1 and DKO-1 cells compared to DKs-8 cells, indicating a widespread effect of mutant KRAS on circRNA abundance. This finding was confirmed in two independent colon cancer cell lines HCT116 (KRAS mutant) and HKe3 (KRAS WT). In all three cell lines, circRNAs were also found in secreted extracellular-vesicles, and circRNAs were more abundant in exosomes than cells. Our results suggest that circRNAs may serve as promising cancer biomarkers. Overall design: RNAseq deep sequencing for both cell and exosome mRNAs
Circular RNAs are down-regulated in KRAS mutant colon cancer cells and can be transferred to exosomes.
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View SamplesExisting controversy regarding the importance of AMP-activated protein kinase (AMPK) in fatty acid (FA) oxidation in skeletal muscle with contraction/exercise may to some extent pertain to redundant AMPK1 signaling. Using a mouse model lacking both AMPK1 and -2 in skeletal muscle specifically (mdKO) we hypothesized that FA utilization would be impaired in skeletal muscle. Calorimetric analysis showed a similar respiratory exchange ratio (RER) of AMPK WT and mdKO mice when fed normal chow, a high fat diet or with prolonged fasting. Though, in vivo treadmill exercise at the same relative intensity induced a higher RER in mdKO mice compared to WT (WT=0.81; mdKO=0.87; p<0.01) indicating a decreased utilization of FA. Ex vivo incubation of soleus muscle revealed that basal and contraction-induced FA oxidation was impaired in mdKO mice, suggesting that the increased RER during in vivo running exercise originated from decreased skeletal muscle FA oxidation. A decreased muscle protein expression of CD36 and FABPpm (by 17-40%) together with abolishment of TBC1D1 Ser237 phosphorylation in mdKO mice, may result in lower FA transport capacity and FA transport protein translocation to sarcolemma, respectively. In summary this study shows that the catalytically active AMPK subunits are required for normal stimulation of FA utilization during exercise and contractions.
AMPKα is critical for enhancing skeletal muscle fatty acid utilization during in vivo exercise in mice.
Specimen part
View SamplesExpression profiling of cultured HL-1 cardiomyocytes subjected to hypoxia for 8 hours.
The VLDL receptor promotes lipotoxicity and increases mortality in mice following an acute myocardial infarction.
Cell line
View SamplesWe examined the microRNAs (miRNAs) expressed in chronic lymphocytic leukemia (CLL) and identified miR-150 as the most abundant, but with leukemia-cell-expression levels that varied among patients. CLL cells that expressed ZAP-70 or that used unmutated IGHV each had a median expression-level of miR-150 that was significantly lower than that of ZAP-70-negative CLL cells or those that used mutated IGHV. In samples stratified for expression of miR-150, CLL cells with low-level miR-150 expressed relatively higher levels of forkhead box P1 (FOXP1) and GRB2-associated binding protein 1 (GAB1), genes with 3 UTRs having evolutionary-conserved binding sites for miR-150. High-level expression of miR-150 could repress expression of these genes, which encode proteins that may enhance B-cell receptor (BCR) signaling, a putative CLL-growth/survival signal. Also, high-level expression of miR-150 levels was a significant independent predictor of longer treatment-free-survival (TFS) or overall survival (OS), whereas an inverse association was observed for high-level expression of GAB1 or FOXP1 for OS. This study demonstrates that expression of miR-150 can influence the relative expression of GAB1 and FOXP1 and the signaling potential of the B-cell receptor (BCR), thereby possibly accounting for the noted association of expression of miR-150 and disease outcome.
miR-150 influences B-cell receptor signaling in chronic lymphocytic leukemia by regulating expression of GAB1 and FOXP1.
Specimen part, Disease stage
View SamplesTo identify genes that are regulated from the lncRNA ANRIL (EXON 13), we designed inducible short hairpin RNA constructs and stable integrated them into HEK cells
The large non-coding RNA ANRIL, which is associated with atherosclerosis, periodontitis and several forms of cancer, regulates ADIPOR1, VAMP3 and C11ORF10.
Disease
View SamplesTo identify genes that are regulated from the lncRNA ANRIL (EXON19), we designed inducible short hairpin RNA constructs and stable integrated them into HEK cells
Linear isoforms of the long noncoding RNA CDKN2B-AS1 regulate the c-myc-enhancer binding factor RBMS1.
Disease
View SamplesGene expression was analyzed and compared of normal mouse hepatocyte, premalignant hepatocytes and fully malignant HCC cells. The results provide valuable information about the gene expression alterations during the chronic process of liver cancer development.
Identification of liver cancer progenitors whose malignant progression depends on autocrine IL-6 signaling.
Specimen part
View SamplesIn a cross-site study we evaluated the performance of ribosomal RNA removal kits from Illumina, Takara/Clontech, Kapa Biosystems, Lexogen, New England Biolabs and Qiagen on intact and degraded RNA samples. We found that all of the kits were capable of performing significant ribosomal depletion, though there were differences in their ease of use. All kits were able to remove ribosomal RNA to below 20% with intact RNA and identify ~14,000 protein coding genes from the Universal Human Reference RNA sample at >1FPKM. Analysis of differentially detected genes among kits suggested that transcript length may be a key factor in library production efficiency. These results provide a roadmap for labs on the strengths of each of these methods and how best to utilize them. Overall design: The Universal Human Reference RNA (Agilent) was diluted to 500 ng/ul in 200ul of RNase-free water and 3.94ul of the Spike-in RNA Variant Control E2 Mix (Lexogen) were added. The sample was split into two aliquots, one of which was then heated at 94° C for 1 hour and 27 minutes. 1ul of ERCC RNA Spike-In Mix 1 was added to both the intact and degraded samples. The final intact and degraded RNA samples were then diluted to 25 ng/uL and were distributed to each of the ten genomics core facilities (members of ABRF) for ribo-depletion and library preparation following vendor protocol. Each site prepared between one and four library types. Indices were assigned by the group to prevent overlapping among libraries. Libraries were pooled at an equimolar concentration from each kit using site-specific quantification and pooling SOPs and return each pool along with individual un-pooled libraries to the designated sequencing site. The sequencing site quantified each pool, multiplexed and sequenced over three high output paired-end 75bp runs on the Illumina NextSeq 500. contributor: The Association of Biomolecular Resource Facilities (ABRF) DNA Sequencing Research Group (DSRG) members
Cross-site comparison of ribosomal depletion kits for Illumina RNAseq library construction.
Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Depletion of DNMT1 in differentiated human cells highlights key classes of sensitive genes and an interplay with polycomb repression.
Sex, Specimen part, Time
View SamplesDNA methylation plays a vital role in the cell, but loss-of-function mutations of the maintenance methyltransferase DNMT1 in normal human cells are lethal, precluding target identification, and existing hypomorphic lines are tumour cells. We generated instead a hypomorphic series in normal hTERT-immortalised fibroblasts using stably integrated short hairpin RNA. Approx 2/3 of sites showed demethylation as expected, with 1/3 showing hypermethylation, and targets were shared between the three independently-derived lines. Enrichment analysis indicated significant losses at promoters and gene bodies with four gene classes most affected: 1)protocadherins, which are key to neural cell identity; 2)genes involved in fat homeostasis/body mass determination; 3)olfactory receptors and 4) cancer/testis antigen (CTA) genes. Overall effects on transcription were relatively small in these fibroblasts, but CTA genes showed robust derepression. Comparison with siRNA-treated cells indicated that shRNA lines show substantial remethylation over time. Regions showing persistent hypomethylation in the shRNA lines were associated with polycomb repression, and were derepressed on addition of an EZH2 inhibitor. Persistent hypermethylation in shRNA lines was in contrast associated with poised promoters. Our results suggest polycomb marking blocks remethylation and indicate the sensitivity of key neural, adipose, and cancer-associated genes to chronic depletion of maintenance methylation activity.
Depletion of DNMT1 in differentiated human cells highlights key classes of sensitive genes and an interplay with polycomb repression.
Sex, Specimen part, Time
View Samples