Lung cancers are documented to have remarkable intratumoral genetic heterogeneity. However, little is known about the heterogeneity of biophysical properties, such as cell motility, and its relationship to early disease pathogenesis and micrometastatic dissemination. In this study, we identified and selected a subpopulation of highly migratory premalignant pulmonary epithelial cells that were observed to migrate through microscale constrictions at up to 100-fold the rate of unselected cells. This enhanced migratory capacity was found to be Rac1-dependent and heritable, as evidenced by maintenance of the phenotype through multiple cell divisions continuing more than 8-weeks post-selection. The morphology of this lung epithelial subpopulation was characterized by increased cell protrusion intensity. In a murine model of micrometastatic seeding and pulmonary colonization, the motility-selected premalignant cells exhibit both enhanced survival in short term assays and enhanced outgrowth of premalignant lesions in longer term assays, thus overcoming important aspects of metastatic inefficiency. Overall, our findings indicate that among premalignant pulmonary epithelial cells, subpopulations with heritable motility-related biophysical properties exist, and these may explain micrometastatic seeding occurring early in the pathogenesis of lung cancer. Understanding, targeting, and preventing these critical biophysical traits and their underlying molecular mechanisms may provide a new approach to prevent metastatic behavior.
Identification of a Human Airway Epithelial Cell Subpopulation with Altered Biophysical, Molecular, and Metastatic Properties.
Age, Specimen part
View SamplesWe have analyzed 2 normal B cells isolated from peripheral blood and 5 CLL specimens with affy 133A microarray for expression.
Aberrant splicing of the E-cadherin transcript is a novel mechanism of gene silencing in chronic lymphocytic leukemia cells.
Specimen part, Disease, Disease stage
View SamplesPU.1 is a key transcription factor for macrophage differentiation. Novel PU.1 target genes were identified by mRNA profiling of PU.1-deficient progenitor cells (PUER) before and after PU.1 activation. We used two different types of Affymetrix DNA-microarrays (430 2.0 arrays and ST 1.0 exon arrays) to characterize the global PU.1-regulated transcriptional program underlying the early processes of macrophage differentiation.
Transcriptomic profiling identifies a PU.1 regulatory network in macrophages.
No sample metadata fields
View SamplesMecp2 loss-of-function has been associated with altered gene expression in many tissues. We characterized gene expression changes within the hippocampi of 3 different Mecp2 loss-of-function mouse models.
An AT-hook domain in MeCP2 determines the clinical course of Rett syndrome and related disorders.
Age, Specimen part
View SamplesClassic ‘position effect’ experiments repositioned genes to the telomere to demonstrate that the epigenetic landscape can dramatically alter gene expression. Here we show that systematic gene knockout collections provide an exceptional resource for interrogating position effects, not only at the telomere but at every single genetic locus. Because deleted genes are replaced by the same reporter gene, interrogation of this reporter provides a sensitive probe into many different chromatin environments while controlling for genetic context. Using this approach we find that, whereas replacement of yeast genes with the kanMX marker does not perturb the chromatin landscape, differences due to gene position account for more than 35% of marker gene activity. We observe chromatin influences different from those reported previously, including an antagonistic interaction between histone H3 lysine 36 trimethylation (H3K36me3) and the Rap1 transcriptional activation site in kanMX that is mediated through a Set2-Rpd3-dependent pathway. This interaction explains why some yeast genes have been resistant to deletion and allows successful generation of these deletion strains using a modified transformation procedure. These findings demonstrate that chromatin regulation is not governed by a uniform ‘histone code’, but by specific interactions between chromatin and genetic factors. Overall design: Data included are RNA-Seq data for 4 heterzygous diploid yeast strains and diploid wild-type. Therea re three replicates for each heterzygous strain, and six replicates for wild-type.
Decoupling epigenetic and genetic effects through systematic analysis of gene position.
Subject
View SamplesSilver nanoparticles are used in consumer products like food contact materials, drinking water technologies and supplements, due to their antimicrobial properties. This leads to an oral uptake and exposure of intestinal cells. In contrast to other studies we found no apoptosis induction by surfactant coated silver nanoparticles in the intestinal cell model Caco-2 in a previous study, although the particles induced oxidative stress, morphological changes and cell death. Therefore, this study aimed to analyze the molecular mechanism of silver nanoparticles in Caco-2 cells. We used global gene expression profiling in differentiated Caco-2 cells, supported by verification of the microarray data by quantitative real time RT-PCR and microscopic analysis, impedance measurements and assays for apoptosis and oxidative stress. Our results revealed that the majority of surfactant coated silver nanoparticles are not taken up into differentiated Caco-2 cells. and probably affect the cells by outside-in signaling. They induce oxidative stress and have an influence on canonical pathways related to FAK, ILK, ERK, MAPK, integrins and adherence and tight junctions, thereby inducing transcription factors like AP1, NFB and NRF2, which mediate cellular reactions in response to oxidative stress and metal ions and induce changes in the cytoskeleton and cell-cell and cell-matrix contacts. The present data confirm the absence of apoptotic cell death. Non-apoptotic, necrotic cell death, especially in the intestine, can cause inflammation and influence the mucosal immune response.
Molecular mechanism of silver nanoparticles in human intestinal cells.
Cell line
View SamplesOncolytic viruses exploit common molecular changes in cancer cells, which are not present in normal cells, to target and kill cancer cells. Ras transformation and defects in type I interferon (IFN)-mediated antiviral responses are known to be the major mechanisms underlying viral oncolysis. Previously, we demonstrated that oncogenic RAS/Mitogen-activated protein kinase kinase (Ras/MEK) activation suppresses the transcription of many IFN-inducible genes in human cancer cells, suggesting that Ras transformation underlies type I IFN defects in cancer cells. Here, we investigated how Ras/MEK downregulates IFN-induced transcription. By conducting promoter deletion analysis of IFN-inducible genes, namely guanylate-binding protein 2 and IFN gamma inducible protein 47 (Ifi47), we identified the IFN regulatory factor 1 (IRF1) binding site as the promoter region responsible for the regulation of transcription by MEK. MEK inhibition promoted transcription of the IFN-inducible genes in wild type mouse embryonic fibroblasts (MEFs), but not in IRF1/ MEFs, showing that IRF1 is involved in MEK-mediated downregulation of IFN-inducible genes. Furthermore, IRF1 protein expression was lower in RasV12 cells compared with vector control NIH3T3 cells, but was restored to equivalent levels by inhibition of MEK. Similarly, the restoration of IRF1 expression by MEK inhibition was observed in human cancer cells. IRF1 re-expression in human cancer cells caused cells to become resistant to infection by the oncolytic vesicular stomatitis virus strain. Together, this work demonstrates that Ras/MEK activation in cancer cells downregulates transcription of IFN-inducible genes by targeting IRF1 expression, resulting in increased susceptibility to viral oncolysis.
Oncogenic Ras inhibits IRF1 to promote viral oncolysis.
No sample metadata fields
View SamplesPirin (PIR) is a putative transcriptional regulator whose expression is silenced in cells bearing the AML1/ETO and PML/RAR leukemogenic fusion proteins and is significantly repressed in a large proportion of acute myeloid leukemias. PIR expression increases during in vitro myeloid differentiation of primary hematopoietic precursor cells, and ablation of PIR in the U937 myelomonocytic cell line or in murine primary hematopoietic precursor cells results in impairment of terminal myeloid differentiation.
Pirin downregulation is a feature of AML and leads to impairment of terminal myeloid differentiation.
Cell line
View SamplesThe data shows the effect of NMD inhbition on cell lines and the change in RNA transcripts. The data also shows comparison of non-transformed cells (tert kert) to a Head and Neck tumorigenic cell line SCC12.
Exon 11 skipping of E-cadherin RNA downregulates its expression in head and neck cancer cells.
Specimen part
View SamplesCharacterization of the transcriptome of normal and abnormal embryos. Overall design: Gene expression profiling of every mono and trisomy.
Human blastocysts of normal and abnormal karyotypes display distinct transcriptome profiles.
Specimen part, Subject
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