Ionizing radiation (IR) has long been associated with reduced hematopoietic function and increased malignancies, although the mechanisms behind this relationship remain poorly understood. The carcinogenic effect of IR has been commonly attributed to the direct induction of DNA damage. We demonstrate that IR exposure results in long-term, somatically heritable, cell-intrinsic reductions in HSC self-renewal that is mediated by C/EBPa and reversed by Notch, both of which are associated with human leukemias. Remarkably, restoration of HSC self-renewal prevents selection for C/EBPa loss of function in previously irradiated HSC pools. We propose that environmental insults prompt HSC to initiate a program limiting their self-renewal to prevent damaged HSC from contributing to hematopoiesis. This "programmed mediocrity" is advantageous for the localized insults animals have evolved to deal with, but becomes tumor promoting when the entire HSC compartment is damaged, such as during total body irradiation, by increasing selective pressure for adaptive oncogenic mutations Overall design: Examination of mRNA levels in in vitro and in vivo Hematopoietic Stem Cell that exposed to IR Ionizing radiation (IR) or control. Each group has three replicates.
Contrasting roles for C/EBPα and Notch in irradiation-induced multipotent hematopoietic progenitor cell defects.
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View SamplesMouse mammary carcinoma cell line 4TO7 was used in this experiment. Six2 overepxression experiment.The mouse Six2 cDNA taken from CMV-sport6 (Open Biosystems) was cloned into a pcDNA3.1-hygromycin vector and transfected into 4TO7 cells, after which stably transfected cells were selected. Gene expression profiles were performed in triplicate for the control and over-expressed lines.
Homeoprotein Six2 promotes breast cancer metastasis via transcriptional and epigenetic control of E-cadherin expression.
Cell line
View SamplesCancer incidence increases in the elderly, although the underlying reasons for this association are unknown. We show that B-progenitors in old mice exhibit profound signaling and metabolic defects, and that expression of BCR-ABL, NRASV12 and MYC reverses these fitness defects, leading to selection of oncogenically-initiated cells and leukemogenesis in old hematopoietic backgrounds. Aging is associated with increased inflammation in the BM microenvironment, and inducing inflammation in young mice phenocopies aging B-lymphopoiesis. Importantly, reducing inflammation in aged mice preserves the function of B-progenitors and prevents NRasV12-mediated oncogenesis. We conclude that chronic microenvironments in old age lead to reductions in the fitness of hematopoietic stem and progenitor cell populations. This reduced progenitor pool fitness leads to selection for cells harboring oncogenic mutations in part due to their ability to correct aging-associated functional defects.
Aging-associated inflammation promotes selection for adaptive oncogenic events in B cell progenitors.
Age, Specimen part
View SamplesThe development of cytostatic-drug resistance renders chemotherapy ineffective in treating ovarian cancer, the most lethal gynaecological malignancy. In many cases, it is difficult to explain the development of drug resistance based on the expression patterns of genes known to be involved in this process. Microarray-based assays can provide information about new genes that are involved in the resistance to cytostatic drugs. This report describes alterations in the level of expression of genes in cisplatin- (CisPt), doxorubicin- (Dox), topotecan- (Top), and paclitaxel- (Pac) resistant variants of W1 and A2780 ovarian cancer cell lines. These drug-resistant variants of the W1 and A2780 cell lines were generated through the stepwise selection of cells tolerant of exposure to the indicated drugs at incrementally increased concentrations. Affymetrix GeneChip Human Genome Array Strips were used for hybridization assays. The genes with significantly altered expression levels (upregulated by more than fivefold or downregulated by less than fivefold relative to the level in the parental line) in the drug-resistant sublines were selected and were filtered using volcano plotting.
Microarray-based detection and expression analysis of extracellular matrix proteins in drug‑resistant ovarian cancer cell lines.
Cell line
View SamplesHere we examined virulence activation in Pseudomonas aeruginosa in response to the synthetic kappa opioid agonist U-50, 488 in nutrient poor media where growth conditions are limited and density dependent quorum sensing is not activated.
Pseudomonas aeruginosa overrides the virulence inducing effect of opioids when it senses an abundance of phosphate.
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View SamplesEmbryonic mouse brain development involves a sequential differentiation of multipotent progenitor cells into neurons and glia. Using microarrays and large 2-D electrophoresis, we investigated the transcriptome and proteome of mouse brains at embryonic days 9.5, 11.5 and 13.5. During this developmental period, neural progenitor cells shift from proliferation to neuronal differentiation. As expected, we detected numerous expression changes between the time points investigated but interestingly, the rate of alteration was about 10% to 13% of all proteins and mRNAs during every two days of development. Furthermore, up- and downregulation was balanced. This was confirmed for two additional stages of development, embryonic day 16 and 18. We hypothesize that during embryonic development, the rate of protein expression alteration is rather constant due to a limitation of cellular resources such as energy, space and free water. The similar complexity found at the transcriptome and proteome level at all stages suggests, that changes in relative concentration of gene products rather than an increased number of gene products dominate throughout cellular differentiation. We found that metabolism and cell cycle related gene products were downregulated in expression when precursor cells switched from proliferation to neuronal differentiation (day 9.5 to 11.5), whereas neuron specific gene products were upregulated. A detailed analysis revealed their implication in differentiation related processes such as rearrangement of the actin cytoskeleton as well as Notch and Wnt signaling pathways.
Transcriptome and proteome analysis of early embryonic mouse brain development.
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View SamplesDuring extreme physiological stress, the intestinal tract can be transformed into a harsh environment characterized by regio- spatial alterations in oxygen, pH, and phosphate concentration. When the human intestine is exposed to extreme medical interventions, the normal flora becomes replaced by pathogenic species whose virulence can be triggered by various physico-chemical cues leading to lethal sepsis. We previously demonstrated that phosphate depletion develops in the mouse intestine following surgical injury and triggers intestinal P. aeruginosa to express a lethal phenotype that can be prevented by oral phosphate ([Pi]) supplementation.
Prevention of siderophore- mediated gut-derived sepsis due to P. aeruginosa can be achieved without iron provision by maintaining local phosphate abundance: role of pH.
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View SamplesP. aeruginosa PAO1 grown as lawns on Nematode Growth Medium prepared without supplementation (NGM Pi<0.1 mM) has high killing ability against C. elegans, however, no mortality in worms has been observed during 48 hrs when feeding on PAO1 lawns grown on phosphate supplemented full NGM Pi 25 mM, pH 6.0 medium.
Red death in Caenorhabditis elegans caused by Pseudomonas aeruginosa PAO1.
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View SamplesCigarette smoking is associated with reduced risk of developing Parkinsons disease (PD). To identify genes that interact with nicotine/smoking, we performed hypothesis-free genome-wide experiments in a paraquat-induced Drosophila model and in a case-control study of PD. We demonstrated that nicotine extends life-span in paraquat-treated Drosophila (P=4E-30). Brain tissue from flies treated with combinations of paraquat and nicotine revealed elevated expression of CG14691 with paraquat which was restored with nicotine co-treatment (P(interaction)=2E-11, P(FDR-adjusted)=4E-7). Independently, variants in the 5 region of SV2C, a human ortholog of CG14691, gave the strongest signal for interaction with smoking (P(interaction)=9E-8). The effect of smoking on PD risk varied six-fold by SV2C genotype (P(heterogeneity)=4E-10). Moreover, SV2C variants identified here were associated with SVC2 gene-expression in the HapMap data. Present results suggest synaptic vesicle protein SV2C plays a role in PD pathogenesis, and that the SV2C genotype may be useful for clinical trials of nicotine for treating PD.
A genetic basis for the variable effect of smoking/nicotine on Parkinson's disease.
Sex, Specimen part
View SamplesThe proper mammalian oocytes maturation is recognized as reaching MII stage and accumulation of mRNA and proteins in cell cytoplasm following fertilization. The proper course of folliculogenesis and oogenesis is orchestrated with morphogenesis significantly influencing further zygote formation and embryos growth. This study was aimed to determinate new transcriptomic markers of porcine oocytes morphogenesis associated with cell maturation capacity.
"Cell Migration" Is the Ontology Group Differentially Expressed in Porcine Oocytes Before and After In Vitro Maturation: A Microarray Approach.
Specimen part
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