Intermediate- and low-methylation epigenotypes do not correspond to CpG island methylator phenotype (low and -zero) in colorectal cancer.
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE37740 | GEO | 2013/03/08
SECONDARY ACCESSION(S): PRJNA163107
REPOSITORIES: GEO
Similar Datasets
Project description:We performed comprehensive genome-scale DNA methylation profiling by Illumina Infinium HumanMethylation27 of 18 DNA pools that represent 84 colorectal cancer (CRC) samples divided according to their high-, intermediate-, and low-methylation epigenotypes (HME, IME, and LME, respectively) and 3 pools representing 70 normal-adjacent colonic tissues. Bisulphite converted DNA from the 21 DNA pools were hybridised to the Illumina Infinium 27k Human Methylation Beadchip v1.2
2013-03-08 | E-GEOD-37740 | biostudies-arrayexpress
Project description:Background Gastric cancer (GC) was characterized by unique DNA methylation epigenotypes (MEs). Still, MEs, including adenocarcinoma of the esophagogastric junction (AEG) and background non-neoplastic columnar mucosae (NM), are yet to be clarified. Methods We analyzed genome-wide DNA MEs of AEG, GC, and background NM using Infinium 450k beadarray, followed by quantitative pyrosequencing validation. Large-scale data of the Cancer Genome Atlas (TCGA) were additionally reviewed. Results Unsupervised two-way hierarchical clustering using Infinium data of 21 AEG, 30 GC, and 11 NM showed four DNA MEs: extremely high-ME (E-HME), high-ME (HME), low-ME (LME), and extremely low-ME (E-LME). The promoter methylation levels were validated by pyrosequencing in 146 samples. Although almost normal mucosae were clustered into E-LME, gastric or esophagogastric junction mucosae with chronic inflammatory change due to either Helicobacter pylori infection or reflux esophagitis were clustered together into LME, which suggested that the inflammation status determined DNA MEs regardless of the causes. Three cases of Barrett’s-related adenocarcinoma were all clustered into HME. Among 94 patients whose tumors can be clustered into one of four MEs, 11 patients with E-LME cancers showed significantly shorter overall survival than the other MEs, even in multivariate Cox regression estimate. TCGA data also showed enrichment of AEG in HME and a poorer prognosis of E-LME. Conclusions E-LME cases, newly confirmed in this study, would be a unique aggressive subtype not associated with the elevation of DNA methylation levels caused by inflammation. LME could be acquired via chronic inflammation independent of the causes, and AEG frequently showed HME.
2022-10-20 | GSE207846 | GEO
Project description:Cell migration is a fundamental process during embryonic development. Most studies on cell migration in vivo have focussed on the migration of cells using the extracellular matrix (ECM) as their substrate for migration. In contrast, much less is known about how cells migrate on other cells, as found in early embryos when the ECM has not yet formed. Here, we show that lateral mesendoderm (LME) cells in the early zebrafish gastrula use the overlying ectoderm as their substrate for migration. We show that the lateral ectoderm is permissive for the animal pole-directed migration of LME cells, while the ectoderm at the animal pole of the gastrula halts animal pole-directed LME migration. These differences in the permissive properties of the ectoderm for LME migration are due to the lateral ectoderm being more cohesive and viscous than the animal ectoderm. Consistently, tuning cell contractility in lateral and animal ectoderm via modulation of the actomyosin cytoskeleton is sufficient to change their permissiveness for LME migration. Finally, we found that BMP signalling is critical for reducing animal ectoderm cohesion and, thus, its capacity to halt LME migration towards the animal pole. Collectively, these findings identify a critical role of ectoderm tissue cohesion and viscosity in guiding LME migration during zebrafish gastrulation.
2025-01-07 | GSE251904 | GEO
Project description:Spliceosomal introns are a ubiquitous feature of eukaryotic genes, whose presence often boosts the expression of their host gene, a phenomenon known as intron-mediated enhancement (IME). IME has been noted across diverse genes and organisms, but remains mysterious in many respects. For example, how does intron sequence affect the magnitude of IME? In this study, we performed a massively parallel reporter assay (MPRA) to assess the effect of varying intron sequence on gene expression in a high-throughput manner, using tens of thousands of synthetic introns with natural splice sites and randomized internal sequence. We observe that most random introns splice efficiently and enhance gene expression as well as or better than fully natural introns. Nearly all introns stimulate gene expression ~eight-fold above an intronless control, at both mRNA and protein levels, suggesting that the primary mechanism acts to increase mRNA levels. IME strength is positively associated with splicing efficiency and with the intronic content of poly-uridine stretches, which we confirm using reporter experiments. In sum, this work elucidates sequence determinants of IME from tens of thousands of random introns.
2024-10-28 | GSE278584 | GEO
Project description:The aim of this study was to uncover the differential transcription regulation pathways between immature embryo (IME)- and mature embryo (ME)-derived callus formation through transcriptome sequencing. We showed that incubation of embryos on auxin-rich medium caused dramatic changes in gene expression profiles within 48 h. A total of 9330 and 11318 differentially expressed genes (DEGs) were found in the IME and ME systems, respectively. 3880 DEGs were found specific to IME_0h/IME_48h, and protein phosphorylation, regulation of transcription, and oxidative-reduction process were the most common gene ontology categories of this group. Twenty-three IAA, 14 ARF, 8 SAUR, 3 YUC, and 4 PIN genes were found to be differentially expressed during callus formation. The effect of callus-inducing medium (CIM) on IAA genes was broader in the IME system than in the ME system, indicating that auxin response in regulating cell reprogramming during callus formation. BBM, LEC1 and PLT2 exhibited a significant increase in expression level during IME system but were not activated in the ME system, WUS showed a more substantial growth trend in the IME system than in the ME system, suggesting that these embryonic, shoot, and root meristems genes play crucial roles in determining the acquisition of competency. In addition, epigenetic regulators—including SUVH3A, SUVH2A, HDA19B/703—exhibited differential expression patterns between the two induction systems, indicating that epigenetic reprogramming might contribute to gene expression activation/suppression in this process.
2022-01-22 | GSE165487 | GEO
Project description:PurposeAberrant promoter methylation and genomic instability occur frequently during colorectal cancer development. CpG island methylator phenotype (CIMP) has been shown to associate with microsatellite instability, and BRAF mutation and is often found in the right-side colon. Nevertheless, the relative importance of CIMP and chromosomal instability (CIN) for tumorigenesis has yet to be thoroughly investigated in sporadic colorectal cancers.Experimental designWe determined CIMP in 161 primary colorectal cancers and 66 matched normal mucosae using a quantitative bisulfite/PCR/ligase detection reaction (LDR)/Universal Array assay. The validity of CIMP was confirmed in a subset of 60 primary tumors using MethyLight assay and five independent markers. In parallel, CIN was analyzed in the same study cohort using Affymetrix 50K Human Mapping arrays.ResultsThe identified CIMP-positive cancers correlate with microsatellite instability (P = 0.075) and the BRAF mutation V600E (P = 0.00005). The array-based high-resolution analysis of chromosomal aberrations indicated that the degree of aneuploidy is spread over a wide spectrum among analyzed colorectal cancers. Whether CIN was defined by copy number variations in selected microsatellite loci (criterion 1) or considered as a continuous variable (criterion 2), CIMP-positive samples showed a strong correlation with low-degree chromosomal aberrations (P = 0.075 and P = 0.012, respectively). Similar correlations were observed when CIMP was determined by MethyLight assay (P = 0.001 and P = 0.013, respectively).ConclusionCIMP-positive tumors generally possess lower chromosomal aberrations, which may only be revealed using a genome-wide approach. The significant difference in the degree of chromosomal aberrations between CIMP-positive and the remainder of samples suggests that epigenetic (CIMP) and genetic (CIN) abnormalities may arise from independent molecular mechanisms of tumor progression.
| S-EPMC3268558 | biostudies-literature
Project description:The CpG island methylator phenotype (CIMP or CIMP-high) with extensive promoter methylation seems to be a distinct epigenotype of colorectal cancer. However, no study has comprehensively examined features of colorectal cancer with less extensive promoter methylation (designated as "CIMP-low"). Using real-time polymerase chain reaction (MethyLight), we quantified DNA methylation in five CIMP-specific gene promoters [CACNA1G, CDKN2A (p16), CRABP1, MLH1, and NEUROG1] in 840 relatively unbiased, population-based colorectal cancer samples, obtained from two large prospective cohort studies. CIMP-low (defined as 1/5 to 3/5 methylated promoters) colorectal cancers were significantly more common among men (38 versus 30% in women, P = 0.01) and among KRAS-mutated tumors (44 versus 30% in KRAS/BRAF wild-type tumors, P = 0.0003; 19% in BRAF-mutated tumors, P < 0.0001). In addition, KRAS mutations were significantly more common in CIMP-low tumors (47%) than in CIMP-high tumors (with > or =4/5 methylated promoters, 12%, P < 0.0001) and CIMP-0 tumors (with 0/5 methylated promoters, 37%, P = 0.007). The associations of CIMP-low tumors with male sex and KRAS mutations still existed after tumors were stratified by microsatellite instability status. In conclusion, CIMP-low colorectal cancer is associated with male sex and KRAS mutations. The hypothesis that CIMP-low tumors are different from CIMP-high and CIMP-0 tumors needs to be tested further.
| S-EPMC1876166 | biostudies-literature
Project description:Aberrant DNA methylation, one of the major epigenetic alterations in cancer, has been reported to accumulate in a subset of colorectal cancer (CRC), so-called CpG island methylator phenotype (CIMP), which was known to correlate with microsatellite instability (MSI)-high CRC. To select new methylation markers genome-widely and epigenotype CRC by DNA methylation comprehensively, we performed methylated DNA immunoprecipitation-on-chip analysis using MSI-high CRC cell line HCT116 and microsatellite-stable SW480, and re-expression array analysis by 5-aza-2-deoxycytidine/Trichostatin A. Methylation levels of 44 new markers selected and 16 previously reported markers were analyzed quantitatively in 149 clinical CRC samples using MALDI-TOF mass spectrometry. By unsupervised two-way hierarchical clustering, CRC was clustered into high-, intermediate-, and low-methylation epigenotypes. Methylation markers were clustered into two groups: Group-1 showing methylation in high-methylation epigenotype and including all the 11 CIMP-related markers except NEUROG1, and Group-2 showing methylation in high- and intermediate-methylation epigenotypes. Marker panel deciding methylation epigenotypes with the highest accuracy was developed: 1st-Panel consisting of Group-1 genes (CACNA1G, LOX, SLC30A10) to extract high-methylation epigenotype, and 2nd-Panel consisting of Group-2 genes (ELMO1, FBN2, THBD, HAND1) and SLC30A10 again to divide the remains into intermediate- and low-methylation epigenotypes. High-methylation epigenotype correlated significantly with BRAF mutation, MSI, proximal tumor location, and mucinous component, in concordance with reported CIMP. Intermediate- and low-methylation epigenotypes significantly correlated with KRAS-mutation(+) and KRAS-mutation(-), respectively. KRAS-mutation(+) intermediate-methylation epigenotype showed worse prognosis than KRAS-mutation(-) low-methylation epigenotype (p=0.030). These three epigenotypes with different genetic characteristics suggested different molecular CRC genesis, and the markers might be useful to predict prognosis.
2010-01-05 | GSE14526 | GEO
Project description:The gene expression of two different tumorigenic human breast epithelial cell types (HMLER and BPLER) is compared with their immortalized parental cell-of-origin (HME and BPE). Experiment Overall Design: Two different normal primary human mammary epithelial cell populations (BPECs and HMECs) were isolated based on their differing in vitro growth requirements. These cells were immortalized by hTERT giving rise to BPE and HME cells. These hTERT immortalized cells (BPE and HME) were transformed by SV40-early region (LT+st) and H-Ras giving rise to transformed tumorigenic derivatives BPLER and HMLER. Biological replicates (4 - 6 samples) for each of 4 cell types were analyzed (untransformed hTERT immortalized cell populations (BPE&HME), and transformed tumorigenic derivatives (BPLER & HMLER).
2008-06-15 | E-GEOD-6885 | biostudies-arrayexpress
Project description:Light travels in a zero-index medium without accumulating a spatial phase, resulting in perfect spatial coherence. Such coherence brings several potential applications, including arbitrarily shaped waveguides, phase-mismatch-free nonlinear propagation, large-area single-mode lasers, and extended superradiance. A promising platform to achieve these applications is an integrated Dirac-cone material that features an impedance-matched zero index. Although an integrated Dirac-cone material eliminates ohmic losses via its purely dielectric structure, it still entails out-of-plane radiation loss, limiting its applications to a small scale. We design an ultra-low-loss integrated Dirac cone material by achieving destructive interference above and below the material. The material consists of a square array of low-aspect-ratio silicon pillars embedded in silicon dioxide, featuring easy fabrication using a standard planar process. This design paves the way for leveraging the perfect spatial coherence of large-area zero-index materials in linear, nonlinear, and quantum optics.
| S-EPMC7791033 | biostudies-literature