The RPMI-8226 human multiple myeloma cell line was stably infected with either a validated shRNA against BMI1 or a control shRNA. RNA was prepared from these lines, +/- doxycycline induction and at various time points post-induction. Samples were hybridized on the Affymetrix U133plus2 human genome expression microarray.
The Polycomb group protein Bmi-1 is essential for the growth of multiple myeloma cells.
Cell line
View SamplesLong wavelength Ultraviolet (UVA-1) radiation causes oxidative stress that leads to the formation of noxious substances within the skin. As a defensive mechanism skin cells produce detoxifying enzymes and antioxidants when they detect modified molecules. We have recently shown that UVA-1 irradiation oxidizes the abundant membrane phospholipid 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (PAPC), which then induced the synthesis of the stress response protein heme oxygenase 1 (HO-1) in dermal fibroblasts. Here we examined the effects of UVA-1 and (UV-) oxidized phospholipids on the global gene expression in human dermal fibroblasts. We identified a cluster of genes that were co-induced by UVA-1-oxidized PAPC and UVA-1 radiation. The cluster included HO-1, glutamate-cysteine ligase modifier subunit (GCLM), aldo-keto reductases-1-C1 and -C2 (AKR1C1, AKR1C2), and interleukin 8 (IL8). These genes are members of the cellular stress response system termed antioxidant response or Phase II detoxification. Accordingly, the regulatory regions of all these genes contain binding sites for NF-E2-related factor 2 (Nrf2), a major regulator of the antioxidant response.
NF-E2-related factor 2 regulates the stress response to UVA-1-oxidized phospholipids in skin cells.
No sample metadata fields
View SamplesBmi-1 and Mel-18 are close structural homologues that belong to the polycomb group (PcG) of transcriptional regulators of homeotic gene expression in development. They are believed to stably maintain repression of gene expression by altering the state of chromatin at specific promoters. A number of clinical and experimental observations have also implicated Bmi-1 in tumorigenesis and stem cell maintenance. Bmi-1 overexpression or amplification has been observed in a number of human malignancies, particularly in B-cell lymphomas, medulloblastomas and breast cancer. We report here that shRNA-mediated knock-down of either Bmi-1 or Mel-18 in human medulloblastoma DAOY cells results in the inhibition of proliferation, loss of clonogenic survival and anchorage-independent growth, and suppression of xenograft tumor formation in nude mice. Furthermore, overexpression of both Bmi-1 and Mel-18 significantly increased clonogenic survival of Rat1 fibroblasts. In contrast, stable downregulation of Bmi-1 or Mel-18 alone did not affect the growth of SK-OV-3 or U2OS cancer cell lines or normal human WI38 fibroblasts. Gene expression analysis of shRNA-expressing DAOY cells has demonstrated a significant overlap in the Bmi-1- and Mel-18-regulated genes and revealed novel gene targets under their control. Taken together, these results suggest that Bmi-1 and Mel-18 might have overlapping functions in human tumorigenesis.
Contribution of polycomb homologues Bmi-1 and Mel-18 to medulloblastoma pathogenesis.
No sample metadata fields
View SamplesMutations in Hedgehog (Hh) pathway genes, leading to constitutive activation of Smoothened (Smo), occur in sporadic medulloblastoma, the most common brain cancer in children. Antagonists of Smo induce tumor regression in mouse models of medulloblastoma and hold great promise for targeted therapy for this tumor. However, acquired resistance has emerged as one of the major challenges of targeted cancer therapy. Here, we describe novel mechanisms of acquired resistance to Smo antagonists in medulloblastoma. NVP-LDE225, a potent and selective Smo antagonist, inhibits Hh signaling and induces tumor regressions in allograft models of medulloblastoma that are driven by mutations of Patched (Ptch), a tumor suppressor in the Hh pathway. However, after long-term treatment, evidence of acquired resistance was observed. Genome-wide profiling of resistant tumors revealed distinct mechanisms to evade the inhibitory effects of Smo antagonists. Chromosomal amplification of Gli2, a downstream effector of Hh signaling, reactivated Hh signaling and restored tumor growth. Analysis of pathway gene-expression signatures selectively deregulated in resistant tumors identified increased phosphoinosite-3-kinase (PI3K) signaling as another potential resistance mechanism. Probing the functional relevance of increased PI3K signaling, we showed that the combination of NVP-LDE225 with the dual PI3K/mTOR inhibitor NVP-BEZ235 markedly delayed the development of resistance. Our findings have important clinical implications for future treatment strategies in medulloblastoma.
Interfering with resistance to smoothened antagonists by inhibition of the PI3K pathway in medulloblastoma.
Treatment
View SamplesGene expression profiling of macrophages derived from WT and Vdr deficient mice after stimulation with IFNgamma and/or 1alpha,25(OH)2D3
1alpha,25-Dihydroxyvitamin D3 is a potent suppressor of interferon gamma-mediated macrophage activation.
No sample metadata fields
View SamplesHuman umbilical vein endothelial cells (HUVECs) were incubated for 48 h after transfection of scrambled siRNA or siRNA targeting Jmjd6 .
Jumonji domain-containing protein 6 (Jmjd6) is required for angiogenic sprouting and regulates splicing of VEGF-receptor 1.
Specimen part, Treatment
View SamplesDiffuse large B-cell lymphoma (DLBCL) represents the most common form of lymphoma. We could show that in DLBCL cell lines the transcription factor NFAT is constitutively activated and drives the survival of a DLBCL subset. Aim of the analysis was to identify NFAT target genes in a NFAT-dependent (HBL-1) or -independent (HT) DLBCL cell line. To block NFAT activity, the DLBCL cells were treated with the calcineurin inhibitor cyclosporin A (CsA) up to 48 h. With this approach, we identified several survival-related NFAT target genes in HBL-1 cells that might explain the toxic effects of calcineurin inhibitors.
Targeting chronic NFAT activation with calcineurin inhibitors in diffuse large B-cell lymphoma.
Treatment
View SamplesWe analyzed the genome-wide expression by RNA-seq of a yeast strain that expresses Cas9d and a guideRNA targeted to the GAL10 locus (called +116), which inhibits GAL10 ncRNA expression from the antisense strand. We compared this strain to a strain expressing a scrambled guideRNA. The goal was to examine the effects of ncRNA inhibition and to examine if CRISPR inhibition of gene expression has off-target effects. We find that CRISPR-mediated inhibtion of GAL10 ncRNA only significantly changes expression of transcripts at the GAL1-10 locus, showing that CRISPR is highly specific, and that GAL10 ncRNA only control genes at the GAL locus. Overall design: RNA-seq of 2 strains with CRISPR scrambled and 2 strains with CRISPR +116, the latter of which inhibits GAL10 ncRNA
Single-Molecule Imaging Reveals a Switch between Spurious and Functional ncRNA Transcription.
Cell line, Subject
View SamplesBACKGROUND: Dendritic cells (DC) play a central role in primary immune responses and become potent stimulators of the adaptive immune response after undergoing the critical process of maturation. Understanding the dynamics of DC maturation would provide key insights into this important process. Time course microarray experiments can provide unique insights into DC maturation dynamics. Replicate experiments are necessary to address the issues of experimental and biological variability. Statistical methods and averaging are often used to identify significant signals. Here a novel strategy for filtering of replicate time course microarray data, which identifies consistent signals between the replicates, is presented and applied to a DC time course microarray experiment.
Dynamics of dendritic cell maturation are identified through a novel filtering strategy applied to biological time-course microarray replicates.
Specimen part
View SamplesTranscriptome analysis of adult hematopoietic stem cells (HSC) and their progeny has informed our understanding of blood differentiation and leukemogenesis, but a similarly transformative analysis of the embryonic origins of hematopoiesis is lacking. To address this issue, we acquired gene expression profiles of developing HSC purified from over 2500 dissected murine embryos and adult mice, and applied a network biology-based analysis to reconstruct the gene regulatory networks of sequential stages of HSC development. We found that embryonic hematopoietic elements clustered into three distinct transcriptional states characteristic of the definitive yolk sac, HSCs emerging from hemogenic endothelium, and definitive HSCs. We functionally validated several candidate transcriptional regulators of HSC ontogeny by morpholino-mediated knock-down in zebrafish embryos, confirming changes in the expression of HSC markers runx1 and c-myb in the aorta-gonads-mesonephros (AGM), the site of definitive HSC specification. Moreover, we found that HSCs derived from differentiating embryonic stem cells in vitro (ESC-HSC) most closely resemble definitive HSC, yet lack a signature indicative of specification by Notch signaling, which likely accounts for their deficient lymphoid development. Our analysis and accompanying web resource will accelerate the characterization of regulators of HSC ontogeny, facilitate efforts to direct hematopoietic differentiation and cell fate conversion, and serve as a model to study the origins of other adult stem cells.
The transcriptional landscape of hematopoietic stem cell ontogeny.
Specimen part
View Samples