Project description:Diffuse Intrinsic Pontine Glioma (DIPG) is a fatal brain cancer that arises in the brainstem of children with no effective treatment and near 100% fatality. The failure of most therapies can be attributed to the delicate location of these tumors and choosing therapies based on assumptions that DIPGs are molecularly similar to adult disease. Recent studies have unraveled the unique genetic make-up of this brain cancer with nearly 80% harboring a K27M-H3.3 or K27M-H3.1 mutation. However, DIPGs are still thought of as one disease with limited understanding of the genetic drivers of these tumors. To understand what drives DIPGs we integrated whole-genome-sequencing with methylation, expression and copy-number profiling, discovering that DIPGs are three molecularly distinct subgroups (H3-K27M, Silent, MYCN) and uncovering a novel recurrent activating mutation in the activin receptor ACVR1, in 20% of DIPGs. Mutations in ACVR1 were constitutively activating, leading to SMAD phosphorylation and increased expression of downstream activin signaling targets ID1 and ID2. Our results highlight distinct molecular subgroups and novel therapeutic targets for this incurable pediatric cancer. Illumina HT-12 arrays were performed according to the manufacturer's directions on RNA extracted from FFPE biopsy and autopsy brain tissue from DIPG patients. Gene expression profiling on Illumina HT-12 arrays was performed for 35 paediatric DIPG samples and 10 normal brain samples
Project description:The MR is an endocytic receptor, which plays an important role in serum homeostasis and antigen presentation. In this study, we firstly describe an important role of the MR as a direct regulator of CD8+ T cell activity. We could demonstrate that the presence of the MR on DCs impaired the cytotoxicity of activated CD8+ T cells both in vitro and in vivo. This regulatory effect was mediated by a direct interaction of the MR with CD45 on the T cells surface, which abolished CD45 activity. MR-mediated suppression of CD45 resulted in the up-regulation of the inhibitory molecule CTLA-4, which in turn was responsible for the reduced T cell activity. MR-mediated inactivation of CD45, up-regulation of CTLA-4 and T cell inactivation could be circumvented by increased signaling via CD28, which was achieved by DC maturation. These implications point out an important role of the MR in maintaining the balance between tolerance and immunity and might have pivotal implications for the development of vaccination strategies aimed at dampening adaptive immunity. DesTCR T cells were incubated with MR-deficient DCs in the presence of FcMR or isotype controls for the indicated time points. Afterwards, CD8+ T cells were isolated by cell sorting (FACSAria), and immediately lysed in Trizol (Invitrogen) before storage at -80°C for RNA isolation.
Project description:Hyporesponsiveness by phagocytes, a well-known phenomenon in sepsis, is frequently induced by low-dose endotoxin-stimulation of Toll-like-receptor-4 (TLR4) but can also be found under sterile inflammatory conditions. We now demonstrate that the endogenous alarmins myeloid-related protein (MRP) 8 and MRP14 induce phagocyte hyporesponsiveness via chromatin modifications in a TLR4-dependent manner resulting in enhanced survival during murine septic shock. Also during sterile inflammation, polytrauma and burn patients present with initially high MRP serum concentrations identifying these proteins as obvious candidates for triggering secondary hyporesponsiveness in these patients. Interestingly, increased peripartal MRP concentrations prime human neonatal phagocytes for hyporesponsiveness, which was confirmed in murine neonatal endotoxinemia in wildtype and MRP14 -/- mice. Using a comparative bioinformatics analysis between genome-wide response patterns of MRP- and LPS- tolerized monocytes we demonstrated no difference in global gene expression between samples pretreated with either MRP8-MRP14 or LPS. Our data indicate that alarmin-triggered phagocyte tolerance represents a novel regulatory mechanism for the susceptibility of neonates to systemic infections and during sterile inflammation. Human blood monocytes prestimulated with MRP8-MRP14 or LPS and afterwards activated with LPS were selected for RNA extraction and hybridization on Illumina microarrays.
Project description:Thyroid hormone has a positive effect on endochondral bone growth. Few studies have looked at the interaction between thyroid hormone exposures and intramembranous bone derived cells. We used microarray as one tool to determine the gene expression profile of intramembranous (calvarial) derived murine pre-osteoblsts after thyroxine exposure. We isolated whole RNA from MC3T3-E1 cells treated with proliferation media or proliferation media with thyroxine at a dose of 10^-6 mol./liter for 3 or 7 days in culture. We then used an Affymetrix array and compared expression profiles between control and experimental treatments.
Project description:The TET family of dioxygenases catalyze conversion of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), but their involvement in establishing normal 5mC patterns during mammalian development and their contributions to aberrant control of 5mC during cellular transformation remains largely unknown. We depleted TET1, TET2, and TET3 by siRNA in a pluripotent embryonic carcinoma cell model and examined the impact on genome-wide 5mC and 5hmC patterns. TET1 depletion yielded widespread reduction of 5hmC, while depletion of TET2 and TET3 reduced 5hmC at a subset of TET1 targets suggesting functional co-dependence. TET2 or TET3-depletion also caused increased 5hmC, suggesting they play a major role in 5hmC removal. All TETs prevent hypermethylation throughout the genome, a finding dramatically illustrated in CpG island shores, where TET depletion resulted in prolific hypermethylation. Surprisingly, TETs also promote methylation, as hypomethylation was associated with 5hmC reduction. TET function was highly specific to chromatin environment: 5hmC maintenance by all TETs occurred at polycomb-marked chromatin and genes expressed at moderate levels; 5hmC removal by TET2 is associated with highly transcribed genes enriched for H3K4me3 and H3K36me3. Importantly, genes prone to hypermethylation in cancer become depleted of 5hmC with TET deficiency, suggesting the TETs normally promote 5hmC at these loci, and all three TETs are required for 5hmC enrichment at enhancers, a condition necessary for expression of adjacent genes. These results provide novel insight into the division of labor among TET proteins and reveal an important connection of TET activity with chromatin landscape and gene expression. Affymetrix gene expression Human ST1.0 microarray of NCCIT human embryonic carcinoma cells (4 samples in duplicate).
Project description:Global patterns of DNA methylation, mediated by the DNA methyltransferases (DNMTs), are disrupted in all cancers by mechanisms that remain largely unknown, hampering their development as therapeutic targets. Combinatorial acute depltion of all DNMTs in a pluripotent human tumor cell line, followed by epigenome and transcriptome analysis, revealed DNMT functions in unprecedented detail. DNMT3B occupancy regulates methylation during differentiation, while an unexpected interplay was discovered in which DNMT1 and DNMT3B antithetically regulate methylation and hydroxymethylation in gene bodies, a finding confirmed in other cell types. DNMT3B mediated nonCpG methylation, while DNMT3L influenced the activity of DNMT3B toward nonCpG versus CpG site methylation. Taken together, these data reveal new functional targets of each DNMT suggesting that isoform selective inhibition would be therapeutically advantageous. Affymetrix gene expression Human Gene 1.0 ST microarray of NCCIT human embryonic carcinoma cells (13 samples in duplicate).
Project description:From our previous data, we found that loss of ATAD3A gene expression in breast cancer cells results in loss of cell motility in vitro and metastasis in vivo. To obtain a better understanding of oncogenic pathway of ATAD3A, we have established the stable ATAD3A knockdown MDA-MB-231 cells using lentiviral strategy. We used the whole genome microarrays to detail the global programme of gene expression after depleting of ATAD3A and identified distinct classes of up or down-regulated metastmir associated with breast cancer cells migration Total RNA was extracted from ATAD3A stable knockdown cells (shATAD3A) and the control cells (shGFP). The labeled RNA was hybridized on U133 plus 2.0 Array. To identify altered gene expression patterns with or without ATAD3A expression, we compared average mRNA expression levels between the ATAD3A knockdown and control MDA-MB-231 cells.
Project description:Tumor cells have an increased need for amino acids. Mammalian cells cannot synthesize essential amino acids; they must obtain these amino acids via specific transporters. Glutamine, though a non-essential amino acid, is critical for tumor cells (glutamine addiction). Entry of amino acids into tumor cells is enhanced by upregulation of specific transporters. If the transporters that are specifically induced in tumor cells are identified, blockade of the induced transporters would constitute a logical strategy for cancer treatment. The transporter SLC6A14 is unique and transports all essential amino acids as well as glutamine and is expressed only at low levels in normal tissues, but induced in colon cancer and in ER+ breast cancer. We have now established the potential of this transporter as a drug target for breast cancer treatment using genetic and pharmacologic approaches. We then examined the progression of breast cancer in Polyoma middle T antigen (Py-MT) Tg mouse on Slc6a14+/+ and Slc6a14-/- background using microarray analysis. We have used three Affy-chips for each tumor sample (Group 1: WT/PyMT; Group 2: Slc6a14-KO/PyMT). Three biological replicates were used for each group.