Bmi-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.
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View SamplesLow affinity Tregs are important for controlling autoimmune diabetes. Overall design: High and low affinity Tregs were isolated from the spleen and pancreatic islets of two-TCR retrogenic mice expressing the insulin-specific TCRs 4-8 and 12-4.4m1.
Cutting Edge: Low-Affinity TCRs Support Regulatory T Cell Function in Autoimmunity.
Age, Specimen part, Subject
View SamplesBriefly, the well characterized female hES cell line H9 was allowed to differentiate into a clonally purified mortal splanchnopleuric mesodermal somatic cell line EN13. The EN13 line was subsequently virally reprogrammed back to an induced pluripotent state (we term re-H9) using OCT4, SOX2, KLF4 retroviral vectors creating isogenic lines of hESC, hiPSC and mortal cells. Our results reveal several important differences between embryo-derived H9 and the induced re-H9 stem cells. We find a dysregulation of genes involved in imprinting and altered expression of X-chromosome localized genes in re-H9 cells.
Suppression of the imprinted gene NNAT and X-chromosome gene activation in isogenic human iPS cells.
Cell line
View SamplesRetinoic-acid receptor-related orphan receptor-?t-positive (ROR?t+) innate lymphoid cells (ILCs) produce interleukin (IL)-22 and IL-17, which are critical for protective immunity against enteric pathogens. The molecular mechanism underlying the development and survival of ROR?t+ ILCs is not thoroughly understood. Here we show that Dedicator of cytokinesis 8 (DOCK8), a scaffolding protein involved in cytoskeletal rearrangement and cell migration, is essential for the protective immunity against Citrobacter rodentium. A comparative RNA sequencing-based analysis reveals an impaired induction of antimicrobial peptides in the colon of DOCK8-deficient mice, which correlates with high susceptibility to infection and a very low number of IL-22-producing ROR?t+ ILCs in their GI tract. Furthermore, DOCK8-deficient ROR?t+ ILCs are less responsive to IL-7 mediated signaling, more prone to apoptosis and produce less IL-22 due to a defect in IL-23-mediated STAT3 phosphorylation. Our studies reveal an unsuspected role of DOCK8 for the function, generation and survival of ROR?t+ ILCs. Overall design: Control and DOCK8 KO mice were infected with 2X109 CFU of Citrobacter rodentium and day 8 post infection mice were sacrificed and their colons were harvested (n=5) . Total RNA was purified from the infected colons with RNeasy mini kit (Qiagen). RNA sequencing was performed (pooled RNA sample from five mice in each group) at Genomic Core Facility Southwestern Medical Center, University of Texas.
DOCK8 regulates protective immunity by controlling the function and survival of RORγt+ ILCs.
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View SamplesThe identifcation of alternatively spliced transcript variants specific to particular biological processes in tumours should increase our understanding of cancer. Hypoxia is an important factor in cancer biology and associated splice variants may present new markers to help with planning treatment. A method was developed to analyse alternative splicing in exon array data, using probeset multiplicity to identify genes with changes in expression across their loci, and a combination of the splicing index and a new metric based on the variation of reliability weighted fold changes to detect changes in the splicing patterns. The approach was validated on a cancer/normal sample dataset in which alternative splicing events had been confirmed using RT-PCR. We then analysed ten head and neck squamous cell carcinomas using exon arrays and identified differentially expressed splice variants in five samples with high versus five with low levels of hypoxia-associated genes (Winter et al, 2007; Cancer Res 67:3441-9). The analysis identified a splice variant of LAMA3 (Laminin 3), LAMA3-A, known to be involved in tumour cell invasion and progression. The full-length transcript of the gene (LAMA3-B) did not appear to be hypoxia-associated. The results were confirmed using qualitative real time PCR. In a series of 59 prospectively-collected head and neck tumours (Winter et al, 2007; Cancer Res 67:3441-9), expression of LAMA3-A had prognostic significance whereas LAMA3-B did not. This work illustrates the potential for alternatively spliced transcripts to act as biomarkers of disease prognosis with improved specificity for particular tissues or conditions over assays which do not discriminate between splice variants.
Exon array analysis of head and neck cancers identifies a hypoxia related splice variant of LAMA3 associated with a poor prognosis.
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View SamplesWe established gene expression profiles of diagnostic bone marrow samples of monozygotic twins with acute lymphoblastic leukemia. We established technical duplicates for each twin.
Prenatal origin of separate evolution of leukemia in identical twins.
Sex, Specimen part, Disease, Disease stage
View SamplesSatellite cells are resident skeletal muscle stem cells responsible for muscle maintenance and repair. In resting muscle, satellite cells are maintained in a quiescent state. Satellite cell activation induces the myogenic commitment factor, MyoD, and cell cycle entry to facilitate transition to a population of proliferating myoblasts that eventually exit the cycle and regenerate muscle tissue. The molecular mechanism involved in the transition of a quiescent satellite cell to a transit-amplifying myoblast is poorly understood.
A role for RNA post-transcriptional regulation in satellite cell activation.
Sex, Specimen part
View SamplesBiologic markers of immune tolerance may facilitate tailoring of immune suppression duration after allogeneic hematopoietic cell transplantation (HCT). In a cross-sectional study, peripheral blood samples were obtained from tolerant (n=15, median 38.5 months post-HCT) and non-tolerant (n=17, median 39.5 post-HCT) HCT recipients and healthy control subjects (n=10) for analysis of immune cell subsets and differential gene expression. There were no significant differences in immune subsets across groups. We identified 281 probe sets unique to the tolerant (TOL) group and 122 for non-tolerant (non-TOL). These were enriched for process networks including NK cell cytotoxicity, antigen presentation, lymphocyte proliferation, and cell cycle and apoptosis. Differential gene expression was enriched for CD56, CD66, and CD14 human lineage-specific gene expression. Differential expression of 20 probe sets between groups was sufficient to develop a classifier with > 90% accuracy, correctly classifying 14/15 TOL cases and 15/17 non-TOL cases. These data suggest that differential gene expression can be utilized to accurately classify tolerant patients following HCT. Prospective investigation of immune tolerance biologic markers is warranted.
Tolerance associated gene expression following allogeneic hematopoietic cell transplantation.
Specimen part, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Brain iron accumulation affects myelin-related molecular systems implicated in a rare neurogenetic disease family with neuropsychiatric features.
Sex, Age, Specimen part, Disease
View SamplesDifferential gene expression is assessed in substantia nigra and basal ganglia of neurodegenertion with brain iron accumulation cases (BIA) compared to matched normal controls (c).
Brain iron accumulation affects myelin-related molecular systems implicated in a rare neurogenetic disease family with neuropsychiatric features.
Sex, Age, Specimen part, Disease
View Samples