This SuperSeries is composed of the SubSeries listed below.
Genome-wide analysis in human colorectal cancer cells reveals ischemia-mediated expression of motility genes via DNA hypomethylation.
Cell line, Treatment
View SamplesDNA hypomethylation is an important epigenetic modification found to occur in many different cancer types, leading to the upregulation of previously silenced genes and loss of genomic stability. We previously demonstrated that hypoxia and hypoglycaemia (ischemia), two common micro-environmental changes in solid tumors, decrease DNA methylation through the downregulation of DNMTs in human colorectal cancer cells. Here, we utilized a genome-wide cross-platform approach to identify genes hypomethylated and upregulated by ischemia. Following exposure to hypoxia or hypoglycaemia, methylated DNA from human colorectal cancer cells (HCT116) was immunoprecipitated and analysed with an Affymetrix promoter array. Additionally, RNA was isolated and analysed in parallel with an Affymetrix expression array. Ingenuity pathway analysis software revealed that a significant proportion of the genes hypomethylated and upregulated were involved in cellular movement, including PLAUR and CYR61. A Matrigel invasion assay revealed that indeed HCT116 cells grown in hypoxic or hypoglycaemic conditions have increased mobility capabilities. Confirmation of upregulated expression of cellular movement genes was performed with qPCR. The correlation between ischemia and metastasis is well established in cancer progression, but the molecular mechanisms responsible for this common observation have not been clearly identified. Our novel results suggest that hypoxia and hypoglycaemia may be driving changes in DNA methylation through downregulation of DNMTs. This is the first report to our knowledge that provides an explanation for the increased metastatic potential seen in ischemic cells; i.e. that ischemia could be driving DNA hypomethylation and increasing expression of cellular movement genes.
Genome-wide analysis in human colorectal cancer cells reveals ischemia-mediated expression of motility genes via DNA hypomethylation.
Cell line, Treatment
View SamplesRecent advances in multiple whole genome technologies provide unprecedented opportunities to profile epigenomic signatures in cancer cells. Previously we used a human gene promoter tiling microarray platform to identify genome-wide DNA methylation changes in a cell line model of breast cancer metastasis. Interestingly, the clustered nature of epigenetic targets that we identified, along with our concurrent karyotype analyses, have now led us to hypothesize that complex genomic alterations in cancer cells (deletions, translocations and ploidy) may be superimposed over promoter-specific methylation events that are responsible for gene-specific expression changes.
Multi-platform whole-genome microarray analyses refine the epigenetic signature of breast cancer metastasis with gene expression and copy number.
Cell line
View SamplesPathologic and epidemiologic evidence has led to a histologic model of breast cancer progression that involves advancement through specific morphologic stages including atypical ductal hyperplasia (ADH), ductal carcinoma in situ (DCIS) and invasive mammary carcinoma (IMC), although not necessarily always in a linear fashion. Numerous observational studies have examined genetic, epigenetic and gene expression differences in breast tissues representing these different stages of progression, but model systems which would allow for experimental testing of specific factors influencing transition through these stages are scarce. The 21T series cell lines, all originally derived from the same patient with metastatic breast cancer, have been proposed to represent a mammary tumor progression series. We report here that three of the 21T cell lines indeed mimic specific stages of human breast cancer progression (21PT-derived cells, ADH; 21NT-derived cells, DCIS; 21MT-1 cells, IMC) when grown in the mammary fat pad of nude mice, albeit after up to a year post-injection. In order to develop a more rapid, readily manipulatable in vitro assay for examining the biologic differences between these cell lines, we have made use of a 3D Matrigel system. When grown in 3D Matrigel, we have found characteristic morphologies of the three cell lines in which quantifiable aspects of the stage-specific in vivo behaviors (i.e. differences in acinar structure formation, cell polarization, cell cohesiveness, cell proliferation, cell invasion) are re-capitulated in a reproducible fashion. Gene expression profiling has revealed a characteristic pattern for each of the three cell lines. Interestingly, WNT pathway alterations are particularly predominant in the early transition from 21PTci (ADH) to 21NTci (DCIS), whereas alterations in expression of genes associated with control of cell motility and invasiveness phenomena are more prominent in the later transition of 21NTci (DCIS) to 21MT-1 (IMC). This system thus reveals potential therapeutic targets and will provide a means of testing the influences of identified genes on transitions between these stages of pre-malignant to malignant growth.
Human 21T breast epithelial cell lines mimic breast cancer progression in vivo and in vitro and show stage-specific gene expression patterns.
No sample metadata fields
View SamplesThis study compares a cell line (MDA-MB-468GFP-LN) that aggressively metastasizes to lymph nodes to its parental line MDA-MB-468GFP. Derivation of the lines is described in Vantyghem et al, Clinical & Experimental Metastasis (2005) 22: 351361. The goal here was to compare the gene expression profile of MDA-MB-468GFP-LN to MDA-MB-468GFP, Compare differential expression to databases of genes known to be involved in either cancer stem cell identification or lymph node specific metastasis in large scale clinical studies, and to confirm genes by RT-PCR
Lymphatic metastasis of breast cancer cells is associated with differential gene expression profiles that predict cancer stem cell-like properties and the ability to survive, establish and grow in a foreign environment.
No sample metadata fields
View SamplesDefective complex I (CI) is the most common type of oxidative phosphorylation (OXPHOS) disease in patients, with an incidence of 1 in 5,000 live births. Complex I deficiency can present in infancy or early adulthood and shows a wide variety of clinical manifestations, including Leigh syndrome, (cardio)myopathy, hypotonia, stroke, ataxia and lactic acidosis. A number of critical processes and factors, like superoxide production, calcium homeostasis, mitochondrial membrane potential and mitochondrial morphology, are known to be involved in clinical CI deficiency, but not all factors are yet known and a complete picture is lacking.
Transcriptional changes in OXPHOS complex I deficiency are related to anti-oxidant pathways and could explain the disturbed calcium homeostasis.
Sex, Age, Specimen part, Disease, Disease stage
View SamplesThis SuperSeries is composed of the SubSeries listed below.
MicroRNA-mRNA interactions in a murine model of hyperoxia-induced bronchopulmonary dysplasia.
Specimen part, Disease, Disease stage, Treatment
View SamplesRecent studies have demonstrated that upon encountering a pathogenic stimulus, robust metabolic rewiring of immune cells occurs. A switch away from oxidative phosphorylation to glycolysis, even in the presence of sufficient amounts of oxygen (akin the Warburg effect), is typically observed in activated innate and adaptive immune cells and is thought to accommodate adequate inflammatory responses. However, whether the Warburg effect is a general phenomenon applicable in human monocytes exposed to different pathogenic stimuli is unknown. Our results using human monocytes from healthy donors demonstrate that the Warburg effect only holds true for TLR4 activated cells. Although activation of other TLRs leads to an increase in glycolysis, no reduction or even an enhancement in oxidative phosphorylation is observed. Moreover, specific metabolic rewiring occurs in TLR4 vs. TLR2 stimulated cells characterized by altered gene expression profiles of pathways related to metabolism, changes in spare respiratory capacity of the cells and differential regulation of mitochondrial enzyme activity. Similarly, results from ex vivo and in vivo studies demonstrate metabolic rewiring of immune cells that is highly dependent on the type of pathogenic stimulus. Although the Warburg effect is observed in human monocytes after TLR4 activation, we propose that this typical metabolic response is not applicable to other inflammatory signalling routes including TLR2 in human monocytes. Instead, each pathogenic stimulus and subsequently activated inflammatory signalling cascade induces specific metabolic rewiring of the immune cell to accommodate an appropriate response.
Microbial stimulation of different Toll-like receptor signalling pathways induces diverse metabolic programmes in human monocytes.
Specimen part, Treatment, Subject
View SamplesA great number of studies have investigated changes induced by morphine exposure in gene expression using several experimental models. In this study, we examined gene expression changes during chronic exposure to morphine during maturation and differentiation of zebrafish CNS.
Whole-genome expression profile in zebrafish embryos after chronic exposure to morphine: identification of new genes associated with neuronal function and mu opioid receptor expression.
Treatment
View SamplesChronic tendon injuries, also known as tendinopathy, are common among professional and recreational athletes. These injuries result in a significant amount of morbidity and health care expenditure and yet little is known about the molecular mechanism leading to tendinopathy. We have used histological evaluation and molecular profiling to determine the gene expression changes in 23 human patients undergoing surgical procedures for the treatment of chronic tendinopathy. Diseased tendons have altered extracellular matrix, fiber disorientation, increased cellular content and vasculature and the absence of inflammatory cells. Global gene expression profiling identified 1783 transcripts with significant different expression patterns in the diseased tendons. Global pathway analysis further suggests altered expression of extracellular matrix proteins and the lack of an appreciable inflammatory response. We have identified pathways and genes regulated in tendinopathy samples that will help contribute to the understanding of the disease towards the development of novel therapeutics.
Regulation of gene expression in human tendinopathy.
Sex, Age, Specimen part, Disease, Disease stage, Subject
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