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SRP015449
Homo sapiens
5 Downloadable Samples
Description
Purpose: Development of resistance to tamoxifen is an important clinical issue in the treatment of patients with breast cancer. Tamoxifen resistance may be the result of the acquisition of epigenetic regulation such as DNA methylation within breast cancer cells resulting in changed mRNA expression of genes being pivotal for estrogen dependent growth. Alternatively, tamoxifen resistance may be due to selection of preexisting resistant cells, which may exhibit cancer stem-like characteristics or a combination of the two mechanisms. Methods: To evaluate the contribution of these possible mechanisms to tamoxifen resistance, we applied modified DNA methylation-specific digital karyotyping (MMSDK) and digital gene expression (DGE) in combination with massively parallel sequencing to analyze a well-established tamoxifen resistant cell line model: MCF-7/S0.5 (tamoxifen sensitive parental cell line) and 4 high-dosage tamoxifen selected resistant offspring sublines (MCF-7/TAMR-1, MCF-7/TAMR-4, MCF-7/TAMR-7 and MCF-7/TAMR-8). MMSDK uses BssHII as mapping enzyme (DNA methylation sensitive enzyme). Both MMSDK and DGE use NlaIII and MmeI to produce 20-21 bp tag. The indexed single-end sequencing was performed by Illumina HiSeq 2000 in BGI-Shenzhen. A dynamic programming algorithm-FASTX-Toolkit implemented in Perl was used to trim the adaptor sequence. The trimmed tags were subjected to quality filtering, so that only tags with sequencing quality higher than 30 for more than 80% of the nucleotides were used for subsequent analysis. For MMSDK tag mapping, we generated a simulated reference library, i.e., BssHII reference library, by in silico enzyme digestion of the human genome (hg19, UCSC) regardless of the methylation state. This library was used as reference for subsequent mapping of the tags in the MMSDK analysis. In the DGE analysis, refMrna (hg19, UCSC) was used as reference for mapping cDNA tags. Subsequently, the Burrows–Wheeler Aligner (BWA) procedure for aligning the MMSDK and DGE tags to the simulated BssHII reference library and refMrna reference library, respectively, was applied. Results: MMSDK libraries using BssHII/NlaIII were generated from the parental tamoxifen sensitive subline MCF-7/S0.5 and the 4 TAMR cell lines: TAMR-1, TAMR-4, TAMR-7 and TAMR-8. The 5 indexed MMSDK libraries were sequenced in one lane and 1.38 Gb clean tag data for all 5 cell lines were obtained, with an average sequencing amount of ~270 Mb per library. On average, 59.5 % of the tags with mapping quality = 20 were mapped back to the simulated BssHII/NlaIII reference library. DGE libraries were also generated from MCF-7/S0.5 and the 4 TAMR cell lines. The 5 indexed DGE libraries were sequenced in one lane and obtained 1.71 Gb clean tag data for all 5 cell lines with an average sequencing amount of ~340 Mb per library. On average, 40.8 % with mapping quality = 20 were mapped back to the simulated NlaIII human transcriptome (refMrna reference library). Our present study demonstrates large differences in global gene expression and DNA methylation profiles between parental tamoxifen-sensitive cell line and 4 high-dosage tamoxifen treatment selected resistant sublines. The tamoxifen resistant cell lines exhibited globally higher methylation level than the parental cell line and an inverse relationship between gene expression and DNA methylation in the promoter regions were noticed. High expression of SOX2 and alterations of other SOX gene family members, E2F gene family members and RB-related pocket protein genes as well as highlighted stem cell pathways imply that cancer initiating cells/stem cells are involved in the resistance to tamoxifen. Overall design: DNA methylation and mRNA expression profiles from tamoxifen sensitive parental cell line MCF-7/S0.5 and 4 high dosage of tamoxifen selected resistant offspring sublines (MCF-7/TAMR-1, MCF-7/TAMR-4, MCF-7/TAMR-7 and MCF-7/TAMR-8) were analyzed by MMSDK and DGE methods, respectively, in combination of massively parallel sequencing, using Illumina HiSeq 2000
Publication Title
Integrative analyses of gene expression and DNA methylation profiles in breast cancer cell line models of tamoxifen-resistance indicate a potential role of cells with stem-like properties.
Sample Metadata Fields
No sample metadata fields
View Samples- Mus musculus
- 224 Downloadable Samples
Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
Ischemic tolerance can be induced by numerous preconditioning stimuli, including various Toll-like receptor (TLR) ligands. We have shown previously that systemic administration of the TLR4 ligand, lipopolysaccharide (LPS) or the TLR9 ligand, unmethylated CpG ODNs prior to transient brain ischemia in mice confers substantial protection against ischemic damage. To elucidate the molecular mechanisms of preconditioning, we compared brain and blood genomic profiles in response to preconditioning with these TLR ligands and to preconditioning via exposure to brief ischemia.
Publication Title
Multiple preconditioning paradigms converge on interferon regulatory factor-dependent signaling to promote tolerance to ischemic brain injury.
Sample Metadata Fields
Specimen part, Treatment
View Samples- Danio rerio
- 6 Downloadable Samples
- Affymetrix Zebrafish Genome Array (zebrafish)
Description
The signaling molecule retinoic acid (RA) regulates rod and cone photoreceptor fate, differentiation, and survival. The purpose of this study was to identify eye-specific genes controlled by RA during photoreceptor differentiation in the zebrafish.
Publication Title
Retinoic Acid Signaling Regulates Differential Expression of the Tandemly-Duplicated Long Wavelength-Sensitive Cone Opsin Genes in Zebrafish.
Sample Metadata Fields
Specimen part
View Samples- Sus scrofa
- 94 Downloadable Samples
- Illumina HiSeq 2500
Description
Chromatin packaging in sperm protects it against DNA fragmentation, and the importance of proper chromatin packaging for boar fertility outcome has become increasingly evident. Little is known however about the molecular mechanisms underlying differences in sperm DNA fragmentation and an understanding of the genes controlling this sperm parameter could help in selecting the best boars for AI use. The aim of this study was to identify differentially expressed genes in testis of Norsvin Landrace and Duroc boars with good and bad sperm DNA fragmentation using transcriptome sequencing and to use the data for polymorphism search. RNA sequence reads were obtained using Illumina technology and mapped by TopHat using the Ensembl pig database. Differentially expressed genes and pathways were analyzed using the R Bioconductor packages edgeR and goseq respectively. Using a false discovery rate of 0.05, 309 and 375 genes were found displaying significant differences in expression level between the good and bad condition in Landrace and Duroc respectively. Of the differentially expressed genes, 72 were found in common for the two breeds. Gene ontology analysis revealed that terms common for the two breeds included extracellular matrix, extracellular region and calcium ion binding. Additionally, different metabolic processes were enriched in Landrace and Duroc, whereas immune response ontologies were found to be important in Landrace. SNP detection in Landrace/Duroc identified 53182/53931 variants in 10924/10748 transcripts and of these, 1573/1827 SNPs occurred in 189/241 unique genes that were also differentially expressed. Possible high impact variants were detected using SnpEff. Transcriptome sequencing identified differentially expressed genes and nucleotide variants related to differences in sperm DNA fragmentation, and functional annotation of the genes pointed towards important biochemical pathways. This study provides insights into the genetic network underlying this trait and is a first step towards using sperm DNA fragmentation for predicting boar fertility. Overall design: Nine Landrace, five low and four high, and eleven Duroc, five low and six high, boars were selected for transcriptome profiling based on their extreme DFI values. The biological replicates within the high and low groups were compared.
Publication Title
RNA sequencing reveals candidate genes and polymorphisms related to sperm DNA integrity in testis tissue from boars.
Sample Metadata Fields
Subject
View Samples- Homo sapiens
- 20 Downloadable Samples
- Affymetrix Human Gene 1.0 ST Array (hugene10st)
Description
The effects of LXR stimulation by GW3965 treatment on global mRNA and miRNA expression in primary human in vitro differentiated adipocytes was investigated using microarray profiling.
Publication Title
LXR is a negative regulator of glucose uptake in human adipocytes.
Sample Metadata Fields
Sex, Age, Specimen part, Subject
View Samples- Homo sapiens
- 10 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
In recent years, several approaches have been taken in the peptide-based immunotherapy of metastatic renal cell carcinoma (RCC), although little is known about HLA presentation on metastases compared to primary tumor and normal tissue of RCC. In this study we compared primary tumor, normal tissue and metastases with the aim of identifying similarities and differences between these tissues. We performed this comparison for two RCC patients on the level of the HLA ligandome using mass spectrometry and for three patients on the level of the transcriptome using oligonucleotide microarrays. The quantitative results show that primary tumor is more similar to metastasis than to normal tissue, both on the level of HLA ligand presentation and mRNA. We were able to characterize a total of 142 peptides in the qualitative analysis of HLA-presented peptides. Six of them were significantly overpresented on metastasis, among them a peptide derived from CD151; fourteen were overpresented on both primary tumor and metastasis compared to normal tissue, among them an HLA ligand derived from tumor protein p53. Thus, we could demonstrate that peptide-based immunotherapy might affect tumor as well as metastasis of RCC, but not healthy kidney tissue. Furthermore we were able to identify several peptides derived from tumor-associated antigens that are suitable for vaccination of metastatic RCC.
Publication Title
HLA ligand profiles of primary renal cell carcinoma maintained in metastases.
Sample Metadata Fields
Sex
View Samples- Drosophila melanogaster
- 18 Downloadable Samples
- Affymetrix Drosophila Genome 2.0 Array (drosophila2)
Description
Heterochromatin protein 1a (HP1a) is a chromatin associated protein that has been well studied in many model organisms, such as Drosophila, where it is a determining factor for classical heterochromatin. HP1a is associated with the two histone methyltransferases SETDB1 and Su(var)3-9, which mediate H3K9 methylation marks and participate in the establishment and spreading of HP1a enriched chromatin. While HP1a is generally regarded as a factor that represses gene transcription, several reports have linked HP1a binding to active genes, and in some cases, it has been shown to stimulate transcriptional activity. To clarify the function of HP1a in transcription regulation and its association with Su(var)3-9, SETDB1 and the chromosome 4 specific protein POF, we conducted genome-wide expression studies and combined the results with available binding data in Drosophila melanogaster. The results suggested that HP1a has a repressing function on chromosome 4, where it preferentially targets non-ubiquitously expressed genes (NUEGs), and a stimulating function in pericentromeric regions. Further, we showed that the effects of SETDB1 and Su(var)3-9 are similar to HP1a, and on chromosome 4, Su(var)3-9, SETDB1 and HP1a target the same genes. In contrast, transposons are repressed by HP1a and Su(var)3-9 but are un-affected by SETDB1 and POF. In addition, we found that the binding level and expression effects of HP1a are affected by gene length. Our results indicate that genes have adapted to be properly expressed in their local chromatin environment.
Publication Title
HP1a, Su(var)3-9, SETDB1 and POF stimulate or repress gene expression depending on genomic position, gene length and expression pattern in Drosophila melanogaster.
Sample Metadata Fields
No sample metadata fields
View Samples- Drosophila melanogaster
- 43 Downloadable Samples
- Affymetrix Drosophila Genome 2.0 Array (drosophila2)
Description
Aneuploidy, i.e., variation in the number of individual chromosomes (chromosomal aneuploidy) or chromosome segment (segmental aneuploidy) is associated with developmental abnormalities and reduced fitness in all species examined, is the leading cause of miscarriages and mental retardations and a hallmark of cancer. Despite their documented importance in disease the effects of aneuploidies on the transcriptome remains largely unknown. Here we have examined the expression output in seven deficiency heterozygotes as single deficiencies and in all pairwise combinations. The results show that genes in one copy are buffered, i.e., are expressed above the expected 50% expression level compared to wild type and the buffering is general and not influenced by additional haploid regions. Long genes are significantly better buffered than short genes and our analysis suggests that gene length is the primary determinant for the degree of buffering. For short genes the degree of buffering depends on expression level and expression pattern. Furthermore, the results show that in deficiency heterozygotes the expression of genes involved in proteolysis is enhanced and negatively correlates with the degree of buffering. Our results suggest that proteolysis is a general response induced by aneuploidy.
Publication Title
Buffering and proteolysis are induced by segmental monosomy in Drosophila melanogaster.
Sample Metadata Fields
Sex
View Samples- Drosophila melanogaster
- 6 Downloadable Samples
- Affymetrix Drosophila Genome Array (drosgenome1)
Description
Analysis of expression in pof mutant and wt 1st instar larvae
Publication Title
Painting of fourth and chromosome-wide regulation of the 4th chromosome in Drosophila melanogaster.
Sample Metadata Fields
Sex, Specimen part
View Samples- Drosophila melanogaster
- 6 Downloadable Samples
- Affymetrix Drosophila Genome 2.0 Array (drosophila2)
Description
Analysis of gene expression in pof deletion mutants. Chromosome 4 genes are down-regulated in pof mutants compared to wildtype control. 200 Drosophila melanogaster first instar larvae were used for each of three biological replicates of y1 w67c23; PofD119/PofD119 and three biological replicates of y1 w67c23 as controls.
Publication Title
Painting of fourth and chromosome-wide regulation of the 4th chromosome in Drosophila melanogaster.
Sample Metadata Fields
Sex, Specimen part
View Samples