Pro-inflammation triggered by microbial lipopolysaccharide (LPS) through Toll-like receptor (TLR) 4 in the presence of interferon (IFN)-g induces cytokine secretion in dendritic cells (DCs) tightly regulated by a defined differentiation program. This DC differentiation is characterized by a dynamic immune activating but also tolerance inducing phenotype associated with irreversible down-modulation of cytokines. CD40L on activated T cells further modifies DC differentiation. Using DNA micro arrays we showed down-regulated mRNA levels of TLR signaling molecules while CD40/CD40L signaling molecules were up-regulated at a time when LPS/IFN-g activated DCs have ceased cytokine expression. Accordingly we demonstrated that CD40/CD40L but not TLR4 or TLR3 signaling mediated by LPS or poly (cytidylic-inosinic) acid (poly I:C) and dsRNA re-established the capacity to secret interleukin (IL)-12 in LPS/IFN-g activated DCs, which have exhausted their potential for cytokine secretion. This resulting TH1 polarizing DC phenotype which lacked accompanying secretion of the crucial immune suppressive IL-10 - enhanced activation of cytotoxic T lymphocytes (CTLs). We therefore conclude that immune modulation is restricted to a secondary T-cell mediated stimulus at an exhausted DC state which prevents an immune tolerant DC phenotype. These findings impacts on the rational design of TLR activated DC-based cancer vaccines for the induction of anti-tumoral CTL responses.
CD40 ligation restores type 1 polarizing capacity in TLR4-activated dendritic cells that have ceased interleukin-12 expression.
No sample metadata fields
View SamplesUpon toll-like receptor (TLR) ligation, dendritic cells (DCs) undergo an activation process referred to as maturation. Over the course of maturation, global DC gene expression is severely altered, resulting in phenotypic changes including DC morphology, migration, immune stimulatory and inhibitory receptor expression, cytokine production, etc.
No associated publication
Sex, Age, Specimen part, Time
View SamplesPAX5-JAK2 has recently been identified as a novel recurrent fusion gene in B-cell precursor acute lymphoblastic leukemia (BCP-ALL) but the function of the encoded chimeric protein has not yet been characterized in detail. Herein we show that the PAX5-JAK2 chimera, which consists of the DNA-binding paired domain of PAX5 and the active kinase domain of JAK2, is a nuclear protein that has the ability to bind to wild-type PAX5 target loci. Moreover, our data provide compelling evidence that PAX5-JAK2 functions as nuclear catalytically active kinase that autophosphorylates and in turn phosphorylates and activates downstream STATs in an apparently non-canonical mode. The chimeric protein also enables cytokine-independent growth of Ba/F3 cells and, therefore, possessing transforming potential. Importantly, the kinase activity of PAX5-JAK2 can be efficiently blocked by JAK2 inhibitors rendering it a potential target for therapeutic intervention. Together, our data show that PAX5-JAK2 simultaneously deregulates the PAX5 downstream transcriptional program and activates the JAK-STAT signaling cascade, and thus, by interfering with these two important pathways, may promote leukemogenesis.
The role of the Janus-faced transcription factor PAX5-JAK2 in acute lymphoblastic leukemia.
Specimen part, Disease, Disease stage
View SamplesPurpose: To define copy number alterations and gene expression signatures underlying pediatric high-grade glioma (HGG). Patients and Methods: We conducted a high-resolution analysis of genomic imbalances in 78 de novo pediatric HGG, including 7 diffuse intrinsic pontine gliomas, and 10 HGG cases arising in children who received cranial irradiation for a previous cancer, using Affymetrix 500K GeneChips. Gene expression signatures for 53 tumors were analyzed with Affymetrix U133v2 arrays. Results were compared with publicly available data from adult tumors. Results: Pediatric and adult glioblastoma were clearly distinguished by frequent gain of chromosome 1q (30% vs 9%) and lower frequency of chromosome 7 gain (13% vs 74%), respectively. The most common focal amplifications also differed, with PDGFRA and EGFR predominant in childhood and adult populations respectively. These common alterations in pediatric HGG were detected at higher frequency in irradiation-induced tumors, suggesting that these are initiating events in childhood gliomagenesis. CDKN2A was the most common tumor suppressor gene targeted by homozygous deletion in pediatric HGG. No IDH1 hotspot mutations were found in pediatric tumors, highlighting molecular differences in pathogenesis between childhood HGG and adult secondary glioblastoma. Integrated copy number and gene expression data indicated that deregulated PDGFRA signaling plays a major role in pediatric HGG. Conclusions: Integrated molecular profiling showed substantial differences in the molecular features underlying pediatric and adult HGG, indicating that findings in adult tumors cannot be simply extrapolated to younger patients. PDGFRA may be a useful target for pediatric HGG including diffuse pontine gliomas.
Integrated molecular genetic profiling of pediatric high-grade gliomas reveals key differences with the adult disease.
Age, Disease
View SamplesPurpose: More than 90% of children with diffuse intrinsic pontine glioma (DIPG) die within 2 years of diagnosis. There is a dire need to identify therapeutic targets, however lack of patient material for research has limited progress. We evaluated a large cohort of diffuse intrinsic pontine gliomas (DIPGs) to identify recurrent genomic abnormalities and gene expression signatures underlying DIPG.
Genome-wide analyses identify recurrent amplifications of receptor tyrosine kinases and cell-cycle regulatory genes in diffuse intrinsic pontine glioma.
Age, Specimen part, Disease
View SamplesMutations in the PTEN, TP53 and RB1 pathways are obligate events in the pathogenesis of human glioblastomas, the highest grade of astrocytoma. To investigate synergy between these tumor suppressors in mice, we induced various combinations of compound deletions conditionally in astrocytes and neural precursors in the mature brain. The resulting highly penetrant astrocytomas showed a spectrum of histopathological variation reminiscent of human tumors, and ranged from grade III to grade IV (glioblastoma). Secondary somatic mutations varied depending on the combination of initiating deletions and were relevant to human disease. Receptor tyrosine kinase amplifications were frequent in tumors initiated by combined conditional deletion of Pten and Tp53, but not when Rb, Pten and Tp53 were simultaneously deleted. Multiple mutations within PI3K and Rb pathways were acquired, however, Mapk activation was not consistently detected in astrocytomas. Gene expression profiling revealed striking similarities to previously described human astrocytoma subclasses. A subset of astrocytomas initiated outside of proliferative niches in the adult brain.
Cooperativity within and among Pten, p53, and Rb pathways induces high-grade astrocytoma in adult brain.
Sex, Specimen part
View SamplesThe morphogen and mitogen, Sonic Hedgehog, activates a Gli1-dependent transcription program that drives proliferation of granule neuron progenitors (GNPs) within the external germinal layer of the postnatally developing cerebellum. Medulloblastomas with mutations activating the Sonic Hedgehog signaling pathway preferentially arise within the external germinal layer, and the tumor cells closely resemble GNPs. Atoh1/Math1, a basic helix-loop-helix transcription factor essential for GNP histogenesis, does not induce medulloblastomas when expressed in primary mouse GNPs that are explanted from the early postnatal cerebellum and transplanted back into the brains of nave mice. However, enforced expression of Atoh1 in primary GNPs enhances the oncogenicity of cells overexpressing Gli1 by almost three orders of magnitude. Unlike Gli1, Atoh1 cannot support GNP proliferation in the absence of Sonic Hedgehog signaling and does not govern expression of canonical cell cycle genes. Instead, Atoh1 maintains GNPs in a Sonic Hedgehog-responsive state by regulating genes that trigger neuronal differentiation, including many expressed in response to bone morphogenic protein-4. Therefore, by targeting multiple genes regulating the differentiation state of GNPs, Atoh1 collaborates with the pro-proliferative Gli1-dependent transcriptional program to influence medulloblastoma development.
Atoh1 inhibits neuronal differentiation and collaborates with Gli1 to generate medulloblastoma-initiating cells.
Age, Specimen part, Treatment
View SamplesMice lacking p53 and one or two alleles of the cyclin D-dependent kinase inhibitor p18Ink4c are prone to medulloblastoma development. The tumor frequency is increased by exposing postnatal animals to ionizing radiation at a time when their cerebella are developing. In irradiated mice engineered to express a floxed p53 allele and a Nestin-Cre transgene, tumor development can be restricted to the brain. Analysis of these animals indicated that inactivation of one or both Ink4c alleles did not affect the time of medulloblastoma onset but increased tumor invasiveness. All such tumors exhibited complete loss of function of the Patched 1 (Ptc1) gene encoding the receptor for sonic hedgehog, and many exhibited other recurrent genetic alterations, including trisomy of chromosome 6, amplification of N-Myc, modest increases in copy number of the Ccnd1 gene encoding cyclin D1, and other complex chromosomal rearrangements. In contrast, medulloblastomas arising in Ptc1+/- mice lacking one or both Ink4c alleles retained p53 function and exhibited only limited genomic instability. Nonetheless, complete inactivation of the wild type Ptc1 allele was a universal event, and trisomy of chromosome 6 was again frequent. The enforced expression of N-Myc or cyclin D1 in primary cerebellar granule neuron precursors isolated from Ink4c-/-, p53-/- mice enabled the cells to initiate medulloblastomas when injected back into the brains of immunocompromised recipient animals. These engineered tumors exhibited gene expression profiles indistinguishable from those of medulloblastomas that arose spontaneously. These results underscore the functional interplay between a network of specific genes that recurrently contribute to medulloblastoma formation.
Genetic alterations in mouse medulloblastomas and generation of tumors de novo from primary cerebellar granule neuron precursors.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
NALP3 inflammasome upregulation and CASP1 cleavage of the glucocorticoid receptor cause glucocorticoid resistance in leukemia cells.
Disease, Cell line, Treatment
View SamplesGenomic technologies have unmasked molecularly distinct subgroups among tumors of the same histological type; but understanding the biologic basis of these subgroups has proved difficult since their defining alterations are often numerous, and the cellular origins of most cancers remain unknown. We sought to decipher complex genomic data sets by matching the genetic alterations contained within these, with candidate cells of origin, to generate accurate disease models. Using an integrated genomic analysis we first identified subgroups of human ependymoma: a form of neural tumor that arises throughout the central nervous system (CNS). Validated alterations included amplifications and homozygous deletions of genes not yet implicated in ependymoma. Matching the transcriptomes of human ependymoma subgroups to those of distinct types of mouse radial glia (RG)neural stem cells (NSCs) that we identified previously to be a candidate cell of origin of ependymoma - allowed us to select RG types most likely to represent cells of origin of disease subgroups. The transcriptome of human cerebral ependymomas that amplify EPHB2 and delete INK4A/ARF matched most closely that of embryonic cerebral Ink4a/Arf-/- RG: remarkably, activation of EphB2 signaling in this RG type, but not others, generated highly penetrant ependymomas that modeled accurately the histology and transcriptome of one human cerebral tumor subgroup (subgroup D). Further comparative genomic analysis revealed selective alterations in the copy number and expression of genes that regulate neural differentiation, particularly synaptogenesis, in both mouse and human subgroup D ependymomas; pinpointing this pathway as a previously unknown target of ependymoma tumorigenesis. Our data demonstrate the power of comparative genomics to sift complex genetic data sets to identify key molecular alterations in cancer subgroups.
Cross-species genomics matches driver mutations and cell compartments to model ependymoma.
Sex, Age, Specimen part, Disease, Disease stage
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