Background The side population (SP) phenotype, a subset of cells that extrude the nucleic acid dye Hoechst 33342, has been reported to be enriched for stem cells in several human normal tissues, cancers and cell lines, and thus may be useful for the identification and isolation of cancer stem cells. Methods We demonstrated the presence of SP fractions in all analyzed tumor cell lines ranging between 7- 20% of cells. To identify gene expression patterns that contribute to SP phenotype, microarray analysis of SP and non-SP cells was performed. We additionally confirmed regulation of some genes by qRT-PCR. Results Surprisingly, only a subset of few genes in SP cells showed altered gene expression. A total of 11 genes in A2C12, 103 genes in cRAF_cMYC and 101 genes in beta5 SP cells were regulated. Most regulated genes are involved in transcription / transcriptional regulation and transport. In addition, we found no enrichment of previously described stem cell marker like CD24a, CD90 or CD133 and also the ABC transporter ABCG2 was only slightly increased in side population fraction of two cell lines. But despite the few differences between SP and non-SP cells, the beta5 tumor cells were highly tumorigenic due to their capacity to form an original murine tumor when injected in NOD/SCID mice. Conclusion These findings stand in contrast to other observations but indicate that there are further factors responsible for the SP phenotype and that SP cells alone are not suitable as a universal stem cell marker.
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Specimen part, Disease, Disease stage, Cell line
View SamplesBackground: Lung cancer is a multistage process with poor prognosis and high morbidity. Importantly, the genetics of dysplasia, a facultative cancer, at the edge of malignant transformation is unknown.
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View SamplesLung cancer is a leading cause of deaths in the world. There is a need to improve an understanding of mechanisms of malignant transformation and to develop genetic markers of disease for better and targeted therapies.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
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Specimen part
View SamplesIntestinal epithelial cells express the lipopolysaccharide (LPS) receptor Toll-like receptor (TLR4) and are responsive to LPS stimulation. Following LPS exposure, epithelial cells, similar to myeloid cells such as macrophages, acquire a state of tolerance. Innate immune tolerance is characterized by a lack of expression of proinflammatory genes in response to repeated stimulation. Tolerant epithelial cells, however, exhibit sustained expression of a distinct set of genes encoding for proteins involved in metabolism and homeostasis. This study comparatively analyzes the gene expression profile 6 hours after LPS stimulation (acute response) versus 6 hours LPS followed by 90 hours incubation in the absence of LPS (tolerant response).
miR-146a mediates protective innate immune tolerance in the neonate intestine.
Specimen part, Cell line, Treatment
View SamplesExtensive molecular profiling of leukemias and preleukemic diseases has revealed that distinct clinical entities, like acute myeloid (AML) and T-lymphoblastic leukemia, share the same pathogenetic mutations. It is not well understood how the cell of origin, accompanying mutations, extracellular signals or structural differences in a mutated gene determine the phenotypic identity of the malignant disease. We studied the relationship of different protein domains of the MN1 oncogene and their effect on the leukemic phenotype, building on the ability of MN1 to induce leukemia without accompanying mutations. We found that the most C-terminal domain of MN1 was required to block myeloid differentiation at an early stage, and deletion of an extended C-terminal domain resulted in loss of myeloid identity and cell differentiation along the T-cell lineage in vivo. Megakaryocytic/erythroid lineage differentiation was blocked by the most N-terminal domain. In addition, the N-terminus was required for proliferation and leukemogenesis in vitro and in vivo through upregulation of HoxA9, HoxA10 and Meis2. Our results provide evidence that a single oncogene can modulate cellular identity of leukemic cells based on its active domains. It is therefore likely that different mutations in the same oncogene may impact cell fate decisions and phenotypic appearance of malignant diseases.
Cell fate decisions in malignant hematopoiesis: leukemia phenotype is determined by distinct functional domains of the MN1 oncogene.
Specimen part
View SamplesMyeloid differentiation is blocked in acute myeloid leukemia (AML), but the molecular mechanisms are not well characterized. MN1 is overexpressed in some AML patients and confers resistance to all-trans retinoic acid (ATRA)-induced differentiation. To understand the role of MN1 as a transcriptional regulator in myeloid differentiation, we fused transcriptional activation (VP16) or repression (M33) domains with MN1 and characterized these cells in vivo. Transcriptional activation of MN1 target genes induced myeloproliferative disease with long latency and differentiation potential to mature neutrophils. A large proportion of differentially expressed genes between leukemic MN1 and differentiation-permissive MN1VP16 cells belonged to the immune response pathway like Irf8 and Ccl9. As MN1 is a co-factor of MEIS1 and RARA, we compared chromatin occupancy between MN1, MEIS1 and RARA. Immune response genes that were upregulated in MN1VP16 cells were co-targeted by MN1 and MEIS1, but not RARA, suggesting that myeloid differentiation is blocked through transcriptional repression of shared target genes of MN1 and MEIS1. Constitutive expression of Irf8 or its target gene Ccl9 identified these genes as potent inhibitors of MN1-induced leukemia. Our data show that MN1 prevents activation of the immune response pathway, and suggest that restoration of Irf8 signalling as a novel therapeutic target in AML.
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View SamplesThe transcription factor Evi1 is essential for the formation and maintenance of hematopoietic stem cells, and induces clonal dominance with malignant progression upon constitutive activation by chromosomal rearrangements or transgene integration events. To understand the immediate and adaptive response of primary murine hematopoietic cells to the transcriptional upregulation of Evi1, we developed an inducible lentiviral vector system with a robust expression switch. We found that Evi1 delays differentiation and promotes survival in myeloid culture conditions, orchestrating a battery of genes involved in stemness (Aldh1a1, Ly6a [Sca1], Abca1, Epcam, among others). Importantly, Evi1 suppresses Cyclins and Cyclin-dependent kinases (Cdk), while it upregulates Cdk inhibitors, inducing quiescence in various proliferation-inducing cytokine conditions and operating in a strictly dose-dependent manner. Hematopoietic cells with persisting Evi1-induction tend to adopt a relatively low expression level. We thus classify Evi1 as a dormancy-inducing oncogene, likely requiring epigenetic and genetic compensation for cell expansion and malignant progression.
Activation of Evi1 inhibits cell cycle progression and differentiation of hematopoietic progenitor cells.
Specimen part
View SamplesDAP12 is a transmembrane protein, expressed as a disulfide-bonded homodimer and bears an immunoreceptor tyrosine-based activation motif (ITAM). DAP12 is broadly expressed in hematopoietic cells and associates with a variety of cell surface receptors in lymphoid and myeloid cells. Macrophages express several DAP12-associated receptors including triggering receptors expressed by myeloid cells (TREM)-1,2 and 3, myeloid DAP12-associating lectin (MDL)-1, CD200R like proteins CD200R3/R4 and CD300C/D/E .
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View SamplesBackground and Aims: In the interleukin-10-deficient (Il10-/-) mouse model of IBD, 10 quantitative trait loci (QTL) have been shown to be associated with colitis susceptibility by linkage analyses on experimental crosses of highly susceptible C3H/HeJBir (C3Bir)-Il10-/- and partially resistant C57BL/6J (B6)-Il10-/- mice. The strongest locus (C3Bir-derived cytokine deficiency-induced colitis susceptibility [Cdcs]1 on Chromosome [Chr] 3) controlled multiple colitogenic subphenotypes and contributed the vast majority to the phenotypic variance in cecum and colon. This was demonstrated by interval-specific Chr 3 congenic mice wherein defined regions of Cdcs1 from C3Bir or B6 were bred into the IL-10-deficient reciprocal background and altered the susceptible or resistant phenotype. Furthermore, this locus likely acts by inducing innate hypo- and adaptive hyperresponsiveness, associated with impaired NFB responses of macrophages. The aim of the present study was to dissect the complexity of Cdcs1 by further development and characterization of reciprocal Cdcs1 congenic strains and to identify potential candidate genes in the congenic interval. Material and Methods: In total, 15 reciprocal congenic strains were generated from Il10-/- mice of either C3H/HeJBir or C57BL/6J backgrounds by 10 cycles of backcrossing. Colitis activity was monitored by histological grading. Candidate genes were identified by fine mapping of congenic intervals, sequencing, microarray analysis and a high-throughput real-time RT-PCR approach using bone marrow-derived macrophages. Results: Within the originally identified Cdcs1-interval, three independent regions were detected that likely contain susceptibility-determining genetic factors (Cdcs1.1, Cdcs1.2, and Cdcs1.3). Combining results of candidate gene approaches revealed Fcgr1, Cnn3, Larp7, and Alpk1 as highly attractive candidate genes with polymorphisms in coding or regulatory regions and expression differences between susceptible and resistant mouse strains. Conclusions: Subcongenic analysis of the major susceptibility locus Cdcs1 on mouse chromosome 3 revealed a complex genetic structure. Candidate gene approaches revealed attractive genes within the identified regions with homologs that are located in human susceptibility regions for IBD.
Cdcs1 a major colitis susceptibility locus in mice; subcongenic analysis reveals genetic complexity.
Sex, Specimen part
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