Colorectal cancer is one of the most common cancers in the world. Histological staging is efficient but combination with molecular markers may improve tumors classification. Gene expression profiles have been defined as prognosis predictors among stage II and III tumors but their implementation in medical practice remains controversial. Stage-II tumors have been recognized as a heterogeneous group and high-risk morphologic features have been retained as justifying adjuvant chemotherapy. We propose here the investigation of clinical features and expression profiles from stage II and stage III colon carcinomas without DNA mismatch repair defect. A series of 130 colon cancer samples was retained. Expression profiles were established on oligonucleotide microarrays and processed in the R/Bioconductor environment. Hierarchical then supervised analyses were successively performed applying the data-sampling approach. A molecular signature of seven genes was found to cluster stage III tumors with an adjusted p-values lower than 10^-10. A subgroup of stage-II tumors aggregated this cluster in both series. No correlation was found between with the disease severity but the function of the discriminating genes suggests that tumors have been classified according to their putative response to adjuvant targeted or classic therapies. Further pharmacogenetic studies might document this observation.
A seven-gene signature aggregates a subgroup of stage II colon cancers with stage III.
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We apply the cellular reprogramming experimental paradigm to two disorders caused by symmetrical copy number variations (CNV) of 7q11.23 and displaying a striking combination of shared as well as symmetrically opposite phenotypes: Williams Beuren syndrome (WBS) and 7q microduplication syndrome (7dupASD). Through a uniquely large and informative cohort of transgene-free patient-derived induced pluripotent stem cells (iPSC), along with their differentiated derivatives, we find that 7q11.23 CNV disrupt transcriptional circuits in disease-relevant pathways already at the pluripotent state. These alterations are then selectively amplified upon differentiation into disease-relevant lineages, thereby establishing the value of large iPSC cohorts in the elucidation of disease-relevant developmental pathways. In addition, we functionally define the quota of transcriptional dysregulation specifically caused by dosage imbalances in GTF2I (also known as TFII-I), a transcription factor in 7q11.23 thought to play a critical role in the two conditions, which we found associated to key repressive chromatin modifiers. Finally, we created an open-access web-based platform (accessible at http://bio.ieo.eu/wbs/ ) to make accessible our multi-layered datasets and integrate contributions by the entire community working on the molecular dissection of the 7q11.23 syndromes. Overall design: We reprogrammed skin fibroblasts from patients harbouring a 7q11.23 hemi-deletion (WBS, 4 patients; +1 atypical deletion, AtWBS) or microduplication (7dupASD; 2 patients), as well as from one unaffected relative and two unrelated controls, using integration-free mRNA-reprogramming, leading to the establishment of a total of 27 characterized iPSC clones. We profiled these by RNAseq (either polyA or ribo-zero). To isolate the contribution of GTF2I to the transcriptional dysregulation, we created stable lines expressing a short hairpin against GTF2I from a representative subset of these iPSC clones, and profiled by RNAseq 7 such lines along with their respective scramble controls. Finally, we also profiled by RNAseq mesenchymal stem cells (MSC) derived from a representative subset of the lines.
RNAontheBENCH: computational and empirical resources for benchmarking RNAseq quantification and differential expression methods.
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Malignant gliomas constitute one of the most significant areas of unmet medical need, due to the invariable failure of surgical eradication and their marked molecular heterogeneity. Accumulating evidence has revealed a critical contribution by the Polycomb axis of epigenetic repression. However, a coherent understanding of the regulatory networks affected by Polycomb during gliomagenesis is still lacking. Here we integrate transcriptomic and epigenomic analyses to define Polycomb-dependent networks that promote gliomagenesis, validating them both in two independent mouse models and in a large cohort of human samples. We found that Polycomb dysregulation in gliomagenesis affects transcriptional networks associated to invasiveness and de-differentiation. The dissection of these networks uncovers Zfp423 as a crtitical Polycomb-dependent transcription factor whose silencing negatively impacts survival. The anti-gliomagenic activity of Zfp423 requires interaction with the SMAD proteins within the BMP signaling pathway, pointing to a novel synergic circuit through which Polycomb inhibits BMP signaling. Overall design: Transcriptomic analysis of two different stages of gliomagenesis
Polycomb dysregulation in gliomagenesis targets a Zfp423-dependent differentiation network.
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Analysis of epigenetic changes of pericytes after ischemia-reperfusion renal injury. The hypothesis tested in the present study was that epigenetic change develope in pericytes after acute kidney injury. This phenotype change would cause pericyte to be more proliferative and profibrotic. Results provide important information of the epigenetic change of pericytes, such as specific mechano-responsive genes, up-regulated specific proliferative and profibrotic functions.
Methylation in pericytes after acute injury promotes chronic kidney disease.
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miRNA high-throughput sequencing was used to investigate endometriosis lesion-specific miRNA expression profiles by comparing a set of paired samples of peritoneal endometriotic lesions and matched healthy surrounding tissue together with eutopic endometrium of the same patients. We found that miRNAs of surrounding peritoneal tissue mask most of the miRNA expression differences that could originate from endometriotic tissue and thus only miRNAs with significantly different levels in the endometriotic lesions compared to peritoneal tissue were detected. According to the results of this study, two miRNAs â€“ miR-34c and miR-449a showed remarkably higher expression in lesions compared to healthy tissue. Overall design: Eleven tissue samples (two endometria, five peritoneal lesions and four matched adjacent normal-appearing tissues) were analysed from two patients with a histologically confirmed diagnosis of moderate-severe endometriosis (III-IV stage)
High-throughput sequencing approach uncovers the miRNome of peritoneal endometriotic lesions and adjacent healthy tissues.
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Transcription factor (TF)-induced reprogramming of somatic cells into induced pluripotent stem cells (iPSC) is associated with genome-wide changes in chromatin modifications. Polycomb-mediated histone H3 lysine-27 trimethylation (H3K27me3) has been proposed as a defining mark that distinguishes the somatic from the iPSC epigenome. Here, we dissected the functional role of H3K27me3 in TF-induced reprogramming through the inactivation of the H3K27 methylase EZH2 at the onset of reprogramming. Our results demonstrate that surprisingly the establishment of functional iPSC proceeds despite global loss of H3K27me3. iPSC lacking EZH2 efficiently silenced the somatic transcriptome and differentiated into tissues derived from the three germ layers. Remarkably, the genome-wide analysis of H3K27me3 in Ezh2 mutant iPSC cells revealed the retention of this mark on a highly selected group of Polycomb targets enriched for developmental regulators controlling the expression of lineage specific genes. Erasure of H3K27me3 from these targets led to a striking impairment in TF-induced reprogramming. These results indicate that PRC2-mediated H3K27 trimethylation is required on a highly selective core of Polycomb targets whose repression enables TF-dependent cell reprogramming.
Cell reprogramming requires silencing of a core subset of polycomb targets.
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Cell-type specific RNA-seq is a powerful approach for unravelling molecular processes of endometrial receptivity, and to detect novel sensitive biomarkers of receptivity. Overall design: 16 paired endometrial tissue samples from pre-receptive (defined as LH2) and receptive phase endometria (defined as LH8) from Estonia (defined as E) and Spain (defined as S) were collected. CD9-positive epithelial cells (defined as epithelium) and CD13-positive stromal cells (defined as stroma) were isolated with fluorescent activated cell sorting (FACS) and full transcriptome analysis was performed by RNA-seq.
Meta-signature of human endometrial receptivity: a meta-analysis and validation study of transcriptomic biomarkers.
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Progesterone (P) acting through its cognate nuclear receptors (PRs) plays an essential role in driving pregnancy-associated branching morphogenesis of the mammary gland. However, the fundamental mechanisms, including global cistromic and acute genomic transcriptional responses that are required to elicit active branching morphogenesis in response to P, have not been elucidated. We used microarray analysis to identify global gene expression signatures that are acutely regulated by PRs in the mouse mammary gland after acute P treatment.
Research resource: progesterone receptor targetome underlying mammary gland branching morphogenesis.
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