Alternative mRNA splicing represents an effective mechanism of regulating gene function and is a key element to increase the coding capacity of the human genome. Today, an increasing number of reports illustrates that aberrant splicing events are common and functionally important for cancer development. However, more comprehensive analyses are warranted to get novel insights into the biology underlying malignancies like e.g. acute myeloid leukemia (AML). Here, we performed a genome-wide screening of splicing events in AML using an exon microarray platform. We analyzed complex karyotype and core binding factor (CBF) AML cases (n=64) in order to evaluate the ability to detect alternative splicing events distinguishing distinct leukemia subgroups. Testing different commercial and open source software tools to compare the respective AML subgroups, we could identify a large number of potentially alternatively spliced transcripts with a certain overlap of the different approaches. Selected candidates were further investigated by PCR and sequence analysis: out of 24 candidate genes studied, we could confirm alternative splice forms in 8 genes of potential pathogenic relevance, such as PRMT1 regulating transcription through histone methylation and participating in DNA damage response, and PTPN6, which encodes for a negative regulator of cell cycle control and apoptosis. In summary, this first large Exon microarray based study demonstrates that transcriptome splicing analysis in AML is feasible but challenging, in particular with regard to the currently available software solutions. Nevertheless, our results show that alternatively spliced candidate genes can be detected, and we provide a guide how to approach such analyses.
A robust estimation of exon expression to identify alternative spliced genes applied to human tissues and cancer samples.
Specimen part, Disease, Disease stage
View SamplesSimilar to embryo-derived stem cells, application of human induced pluripotent stem cells (iPSCs) is limited by our understanding of lineage specification. Here, we demonstrate the ability to generate progenitors and mature cells of the hematopoietic fate directly from human dermal fibroblasts without establishing pluripotency. POU domain activation of hematopoietic transcription factors by ectopic expression of Oct-4, together with specific cytokine treatment, allowed generation of cells expressing the pan-leukocyte marker CD45. These unique fibroblast-derived cells gave rise to granulocytic, monocytic, megakaryocytic, and
Direct conversion of human fibroblasts to multilineage blood progenitors.
Sex, Specimen part, Time
View SamplesSpecific microRNA (miRNA) signatures have been associated with different cytogenetic subtypes in acute leukemias. This finding prompted us to investigate potential associations between genetic abnormalities in multiple myeloma (MM) and singular miRNA expression profiles. Moreover, global gene expression profiling was also analyzed to find correlated miRNA-gene expression and select miRNA target genes that show such correlation. For this purpose, we analyzed the expression level of 365 miRNAs and the gene expression profiling in sixty newly diagnosed MM patients, selected to represent the most relevant recurrent genetic abnormalities. Supervised analysis showed significantly deregulated miRNAs in the different cytogenetic subtypes as compared to normal PC. Interestingly, miR-1 and miR-133a clustered on the same chromosomal loci, were specifically overexpressed in the cases with t(14;16). The analysis of the relationship between miRNA expression and their respective target genes showed a conserved inverse correlation between several miRNAs deregulated in MM cells and CCND2 expression level. These results illustrate, for the first time, that miRNA expression pattern in MM is associated with genetic abnormalities, and that the correlation of the expression profile of miRNA and their putative mRNA targets is useful to find statistically significant protein-coding genes in MM pathogenesis associated to changes in specific miRNAs.
Deregulation of microRNA expression in the different genetic subtypes of multiple myeloma and correlation with gene expression profiling.
Specimen part, Disease
View SamplesIncreasing evidence suggests that cancer arises from cells that are capable of initiating and sustaining neoplastic tissue growth, termed cancer stem cells (CSCs). Of central scientific and clinical relevance, cells with CSC properties are enriched for chemo- and radiation resistance and therefore may represent a population of cells that must be therapeutically targeted to prevent cancer recurrence/relapse 1. Human CSCs were first isolated in neoplastic hematopoietic tissue that manifests leukemias such as adult acute myeloid leukemia (AML) 2. AML stem cells represent a benchmark model of human CSC biology, ultimately motivating foundational studies leading to the identification of CSCs from solid tumours such as breast and colon 3. Independent of tissue type, a consistent feature of CSCs is their uncontrolled self-renewal capacity and differentiation blockade that have been commonly related to aberrant activation of pro-oncogenic events such as dysregulation of CBP/p300 transcriptional regulation involving -catenin 4. However, the transcriptional networks involving CBP/p300/-catenin complex have been shown to be equally critical to maintain normal stem cell (SCs) self-renewal for tissue homeostasis and regeneration 5. Here, we identify Sam68 as a distinct target that affords the ability to uniquely regulate CBP mediated transcription in human CSCs. Using a small molecule that targets Sam68, we reveal that shifting its affinity for CBP disrupts CBP/-catenin complexes, leading to immediate changes in histone H3 (K14 and K18) acetylation. Chemical targeting of Sam68 induced global changes in transcriptional programs of patient AML cells involving apoptosis and differentiation and was able to uniquely reduce neoplastic self-renewal of human CSCs in an in vivo model of patient specific acute myeloid leukemia (AML). Our study establishes an approach whereby the CBP/-catenin transcriptome can be uniquely targeted via Sam68 based vulnerability of CSCs that impacts neoplastic differentiation and self-renewal.
Sam68 Allows Selective Targeting of Human Cancer Stem Cells.
Specimen part, Treatment
View SamplesThe purpose of this study was to search for microgravity-sensitive genes, specifically for apoptotic genes influenced by the microgravity environment and other genes related to immune response.
Gene expression alterations in activated human T-cells induced by modeled microgravity.
No sample metadata fields
View SamplesThe below table includes a smaller list of data that was analyzed by dChip and filtered by pvalue such that a file with about 4600 genes was obtained, which allowed for ease of use from 40,000 genes.
Identification of mechanosensitive genes in osteoblasts by comparative microarray studies using the rotating wall vessel and the random positioning machine.
Specimen part
View SamplesThe miR-16 family, which targets genes important for the G1-S transition, is a known modulator of the cell cycle, and members of this family are often deleted or down-regulated in many types of cancers. Here we report the reciprocal relationship - that of the cell cycle controlling the miR-16 family. Levels of this family increase rapidly as cells are arrested in G0. Conversely, as cells are released from G0 arrest, levels of the miR-16 family rapidly decrease. Such rapid changes are made possible by the unusual instabilities of several family members. The repression mediated by the miR-16 family is sensitive to these cell cycle changes, which suggests that the rapid up-regulation of the miR-16 family reinforces cell cycle arrest in G0. Upon cell cycle re-entry, the rapid decay of several members allows levels of the family to decrease, alleviating repression of target genes and allowing proper resumption of the cell cycle. Overall design: Small RNAs were profiled by high-throughput sequencing either during synchronous release after serum starvation or during cell-cycle arrest by contact inhibition.
MicroRNA destabilization enables dynamic regulation of the miR-16 family in response to cell-cycle changes.
Specimen part, Cell line, Subject
View SamplesTranslation and mRNA decay are intimately connected processes, and translational inhibition often precedes and stimulates transcript degradation. Here, we have focused on methods that allow determination of mRNA stability on a transcriptome-wide scale. We describe experimental and computational methods for the two most commonly used approaches (transcriptional inhibition and metabolic labeling), and we discuss associated caveats. Overall design: Metabolic labeling time courses (1, 2, 4, 8, 12, 24 hr) using 4SU were performed in HEK293.
Determining mRNA half-lives on a transcriptome-wide scale.
Treatment, Subject
View SamplesOlfactory sensory neurons express just one out of a possible ~1000 odorant receptor genes, reflecting an exquisite mode of gene regulation. In one model, once an odorant receptor is chosen for expression, other receptor genes are suppressed by a negative feedback mechanism, ensuring a stable functional identity of the sensory neuron for the lifetime of the cell. The signal transduction mechanism subserving odorant receptor gene silencing remains obscure, however. Here we demonstrate in the zebrafish that odorant receptor gene silencing is dependent on receptor activity. Moreover, we show that signaling through G protein ß? subunits is both necessary and sufficient to suppress the expression of odorant receptor genes, and likely acts through histone methylation to maintain the silenced odorant receptor genes in transcriptionally inactive heterochromatin. These results provide new insights linking receptor activity with the epigenetic mechanisms responsible for ensuring the expression of one odorant receptor per olfactory sensory neuron. Overall design: Total 6 samples were analyzed-3 controls & 3 samples
Normalization of RNA-seq data using factor analysis of control genes or samples.
No sample metadata fields
View SamplesAbstract. The role of platelets in hemostasis and thrombosis is clearly established; however, the mechanisms by which platelets mediate inflammatory and immune pathways are less well understood. Platelets interact and modulate the function of blood and vascular cells by releasing bioactive molecules. Although the platelet is anucleate, it contains transcripts that may mirror disease. Platelet mRNA is only associated with low-level protein translation, however, platelets have a unique membrane structure allowing for the passage of small molecules, leading to the possibility that its cytoplasmic RNA may be passed to nucleated cells. To examine this question, platelet-like particles with labeled RNA were co-cultured with vascular cells. Co-culture of platelet-like particles with activated THP-1, monocytic, and endothelial cells led to visual and functional RNA transfer. Post-transfer microarray gene expression analysis of THP-1 cells showed an increase in HBG1/HBG2 and HBA1/HBA2 expression which was directly related to the transfer. Infusion of wild-type platelets into a TLR2 deficient mouse model established in vivo confirmation of select platelet RNA transfer to leukocytes. By specifically transferring green fluorescent protein, it was also observed that external RNA was functional in the recipient cells. The observation that platelets possess the capacity to transfer cytosolic RNA suggests a new function for platelets in the regulation of vascular homeostasis.
Platelets and platelet-like particles mediate intercellular RNA transfer.
Specimen part, Cell line
View Samples