The functional shift of quiescent endothelial cells into tip cells that migrate and stalk cells that proliferate is a key event during sprouting angiogenesis. We previously showed that the sialomucin CD34 is expressed in a small subset of cultured endothelial cells and that these cells extend filopodia: a hallmark of tip cells in vivo. In the present study, we characterized endothelial cells expressing CD34 in endothelial monolayers in vitro. We found that CD34-positive human umbilical vein endothelial cells show low proliferation activity and increased mRNA expression of all known tip cell markers, as compared to CD34- negative cells. Genome-wide mRNA profiling analysis of CD34-positive endothelial cells demonstrated enrichment for biological functions related to angiogenesis and migration, whereas CD34-negative cells were enriched for functions related to proliferation. In addition, we found an increase or decrease of CD34-positive cells in vitro upon exposure to stimuli that enhance or limit the number of tip cells in vivo, respectively. Our findings suggest cells with virtually all known properties of tip cells are present in vascular endothelial cell cultures and that they can be isolated based on expression of CD34. This novel strategy may open alternative avenues for future studies of molecular processes and functions in tip cells in angiogenesis.
CD34 marks angiogenic tip cells in human vascular endothelial cell cultures.
Specimen part, Subject
View SamplesBoth spotted long oligonucleotide arrays (GPL1384) and Affymetrix GeneChip arrays (GPL96) were used to analyze gene expression in six human head and neck squamous cell carinoma samples versus control samples or lymph node metastases of the same patients. Hybridizations of HG-U133A GeneChip arrays were performed using standard Affymetrix protocols and equipment. Before hybridization on DKFZ Operon 27k long oligonucleotide arrays, 2 g RNA were amplified by one round of linear isothermal RNA amplification, followed by Cy-dUTP incorporation using Klenow fragment. Hybridizations were performed for 16 h at 42 C in a GeneTAC Hybridization Station (Genomic Solutions) using UltraHyb hybridization buffer (Ambion). Hybridized microarrays were scanned at 5 m resolution on a GenePix 4000B microarray scanner (Axon Instruments). Raw signal intensities from both platforms were normalized applying variance stabilization (W. Huber et al., Bioinformatics 18 Suppl 1, 2002). Expression ratios were compared for those genes represented in both array platforms.
Patient-based cross-platform comparison of oligonucleotide microarray expression profiles.
No sample metadata fields
View SamplesGrowth factor independence genes (Gfi1 and Gfi1b) repress recombination activating genes (Rag) transcription in developing B lymphocytes. Because all blood lineages originate from hematopoietic stem cells (HSCs) and different lineage progenitors have been shown to share transcription factor networks prior to cell fate commitment, we hypothesized that GFI family proteins may also play a role in repressing Rag transcription or a global lymphoid transcriptional program in other blood lineages. We tested the level of Rag transcription in various blood cells when Gfi1 and Gfi1b were deleted, and observed an upregulation of Rag expression in plasmacytoid dendritic cells (pDCs). Using microarray analysis, we observed that Gfi1 and Gfi1b regulate a broad spectrum of cellular processes in pDCs, but not a lymphoid specific transcriptional program. This study establishes a role for Gfi1 and Gfi1b in Rag regulation in a non-B lineage cell type
Gfi1 and gfi1b repress rag transcription in plasmacytoid dendritic cells in vitro.
No sample metadata fields
View SamplesGenome-wide association studies (GWAS) have identified dozens of genomic loci, whose single nucleotide polymorphisms (SNPs) predispose to prostate cancer (PCa). However, the biological functions of these common genetic variants and the mechanisms to increase disease risk are largely unknown. We integrated chromatin-IP coupled sequencing (ChIP-seq) and microarray expression profiling in the TMPRSS2-ERG gene rearrangement positive DuCaP cell model with the NHGRI GWAS PCa risk SNPs catalog, in an attempt to identify disease susceptibility SNPs localized within functional androgen receptor binding sites (ARBSs). Among the 48 GWAS index SNPs and 2,702 linked SNPs defined by the 1000G project 104 were found to be localized in the AR ChIP-seq peaks. Of these risk SNPs, rs11891426 T/G in the 7th intron of its host gene melanophilin (MLPH) was found located within a putative auxiliary ARE motif, which we found enriched in the neighborhood of canonical ARE motifs. Exchange of T to G attenuated the transcriptional activity of the MLPH-ARBS in a reporter gene assay. The expression of MLPH protein in tissue samples from prostate cancer patients was significantly lower in those with the G compared to the T allele. Moreover, a significant positive correlation of AR and MLPH protein expression levels was also confirmed in tissue samples. These results unravel a hidden link between AR and a functional PCa risk SNP rs11891426, whose allele alteration affects androgen regulation of its host gene MLPH. This study shows the power of integrative studies to pin down functional risk SNPs and justifies further investigations.
Putative Prostate Cancer Risk SNP in an Androgen Receptor-Binding Site of the Melanophilin Gene Illustrates Enrichment of Risk SNPs in Androgen Receptor Target Sites.
Cell line, Treatment, Time
View SamplesWe used microarrays to detect the differences in gene-expression of the periontal ligament between patients with healthy periodontal ligament and patients with periodontitis
The pathology of bone tissue during peri-implantitis.
Specimen part
View SamplesIn this study we want to ascertain the differences and similarities of infected and inflammated peri implant tissue versus healthy peri implant tissue at the mRNA level.
The pathology of bone tissue during peri-implantitis.
Specimen part, Disease, Disease stage
View SamplesWe have conducted a screen for factors that downregulate expression of the genes encoding the V(D)J recombinase (RAG1 and RAG2) during B cell development. We have identified the transcription factor Gfi1B as being one of the proteins capable of decreasing RAG transcription when overexpressed in Ableson transormed ProB cell lines. We have yet to determine whether the overexpression of Gfi1B downregulates the RAGs directly, or whether it initiates a signalling programme that results in RAG downregulation. We hypothesize that by comparing global gene expression patterns in cells that overexpress Gfi1B and those that do not, we can distinguish between these possibilities and additionally gain insight into the broader genetic program that may be influenced by Gfi1B during hematopoiesis.
Gfi1b negatively regulates Rag expression directly and via the repression of FoxO1.
Cell line
View SamplesWNT-induced secreted protein 1 (WISP1/CCN4), a member of the CCN protein family, acts as a downstream factor of the canonical WNT-signaling pathway. A dysregulated expression of WISP1 often reflects its oncogenic potential by inhibition of apoptosis, a necessary form of cell death that protect cell populations for transformation into malignant phenotypes. WISP1-signaling is also known to affect proliferation and differentiation of human mesenchymal stem cells (hMSCs), which are fundamental for the constitution and maintenance of the musculoskeletal system. Our study emphasizes the importance of WISP1-signaling for cell survival of primary human cells. Therefore, we established a successful down-regulation of endogenous WISP1 transcripts through gene silencing in hMSCs. We were able to demonstrate the consequence of cell death immediately after WISP1 down-regulation took place. Bioinformatical analyses of subsequent performed microarrays from WISP1 down-regulated vs. control samples confirmed this observation. We uncovered several clusters of differential expressed genes important for cellular apoptosis induction and immuno-regulatory processes, thereby indicating TRAIL-induced and p53-mediated apoptosis as well as IFNbeta-signaling. Since all of them act as potent inhibitors for malignant cell growth, in vitro knowledge about the connection with WISP1-signaling could help to find new therapeutic approaches concerning cancerogenesis and tumor growth in musculoskeletal tissues.
WISP 1 is an important survival factor in human mesenchymal stromal cells.
Specimen part, Treatment
View SamplesIn this study we analyzed the myeloma cell contact-mediated changes on the transcriptome of skeletal precursor cells. Therefore, human mesenchymal stem cells (MSC) and osteogenic precursor cells (OPC) were co-cultured with the representative myeloma cell line INA-6 for 24 h. Afterwards, MSC and OPC were separated from INA-6 cells by fluorescence activated cell sorting. Total RNA of MSC and OPC fractions was used for whole genome array analysis.
Contact of myeloma cells induces a characteristic transcriptome signature in skeletal precursor cells -Implications for myeloma bone disease.
Sex, Age, Specimen part, Disease stage
View SamplesBackground and Aim: Fra-1 (Fos-related antigen-1) is a member of the AP1 (activator protein-1) family of transcription factors. We have recently shown that Fra-1 is necessary for breast cancer cells to metastasize in vivo, and that breast cancer outcome can be predicted by a classifier comprising genes that are expressed in a Fra-1-dependent fashion. Here, we show that Fra-1 plays an important role also in colon cancer progression. Methods: We compared proliferation rates of parental and Fra-1-depleted colon cancer cells in vitro under 2D, 3D, and attachment-free conditions and in vivo upon subcutaneous and intravenous injections into mice. We also compared RNA expression profiles of colon cancer cells with and without Fra-1 expression. Results: Fra-1 depletion impair colony outgrowth of human colon cancer cells in soft agar and in suspension, whereas it does not affect proliferation on 2D culture plates. Consistent with this, upon subcutaneous injection into mice, tumors formed by Fra-1-depleted colon cancer cells are only three times smaller than those produced by control cells. In contrast, when injected intravenously, Fra-1 depletion causes 200-fold reduction in tumor burden. Consistent with the more aggressive characteristics of Fra-1-proficient tumors, the prognosis of colon cancer patients can be predicted by a Fra-1 classifier generated by comparing RNA profiles of parental and Fra-1-depleted colon cancer cells. Conclusions: Our results demonstrate that Fra-1 is an important determinant of the metastatic potential of human colon cancer cells, and suggest that a Fra-1 classifier can be used as a prognostic predictor in colon cancer patients. Overall design: HT29 cell line, two shRNAs against Fra-1, one empty vector control, three biological replicates
Fra-1 is a key driver of colon cancer metastasis and a Fra-1 classifier predicts disease-free survival.
No sample metadata fields
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