MSI analysis using blood-derived MSI markers
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PROVIDER: PRJEB53321 | ENA |
REPOSITORIES: ENA
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Project description:Colorectal cancer, one of the most frequent types of malignancy in the Western world, develops through a multi-step process. The main pathways establishing transformation of normal mucosa to invasive carcinoma include chromosomal instability (CIN), microsatellite instability (MSI) or epigenetic silencing through the CpG Island Methylator Phenotype (CIMP). These pathways have distinct clinical, pathological and genetic characteristics. In general, altered cell surface glycosylation has been linked to colorectal cancer progression, however the impact of MSI-specific pathways on the glycosylation machinery of MSI colon cancer cells has not been investigated yet. In a recent study (Patsos et al., 2009) we have shown that MSI-specific mutations induce marked alterations in cell surface glycosylation, indicating specific changes in the expression of glyco-genes. Therefore the purpose of our experiment is to define these changes by glyco-gene chip analysis. Biallelic mutational inactivation of MSI target genes is believed to drive MSI tumorigenesis. TGFBR2, ACVR2 and AIM2 are among the most frequently mutated genes in MSI colorectal adenomas and carcinomas and functional studies indicate their contribution to MSI-carcinogenesis. A first general screening approach by lectin FACS analysis indicated a correlation between functional inactivation of these genes and cell surface glycosylation of the MSI colon cell line HCT116 (Patsos et al., 2009). For detailed analysis of the altered glycosylation pattern and the underlying molecular mechanisms we have established HCT116 double stable transfectants that allow doxycycline-inducible expression of the three MSI target genes TGFBR2, ACVR2 and AIM2 in a reversible manner. Thus we can experimentally control the expression of the MSI-genes and analyze short and long-term effects on different cell functions, including glycosylation. From the application of the glyco-gene chip for analysis of the transfectants we expect to gain seminal information on the influence of MSI-target genes on glycan expression and function in MSI tumor cells. Correlating loss-of-function of MSI target genes not yet linked with glycosylation to the regulation of the glycophenotype is a novel approach to investigate the glycobiology of tumor cells. In addition it is also suitable to detect new MSI-(glyco)markers for clinical applications, including diagnostic tumor markers and specific targets for immunotherapies.
2011-09-05 | E-GEOD-31927 | biostudies-arrayexpress
Project description:Inhibition of the nonsense mediated decay (NMD) mechanism in cells results in stabilization of transcripts carrying premature translation termination codons. A strategy referred to as gene indentification by NMD inhibition (GINI) has been proposed to identify genes carrying nonsense mutations (Noensie & Dietz, 2001). Genes containing frameshift mutations in colon cancer cell line have been identifying mutatnt genes using GINI, we have now further improved the strategy. In this approach, inhibition of NMD with emetine is complemented with inhibiting NMD by blocking the phosphorylation of the hUpf1 protein with caffeine. In addition, to enhance the GINI strategy, comparing mRNA level alterations produced by inhibiting transcription alone or inhbiiting transcription together with NMD following caffeine pretreatment were used for the efficient identification of false positives produced as a result of stress response to NMD inhibition. To demonstrate the improved efficiency of this approach, we analyzed colon cancer cell lines showing microstellite instability. Bi-allelic inactivating mutations were found in the FXR1, SEC1L1, NCOR1, BAT3, PHD14, ZNF294, C190ORF5 genes as well as genes coding for proteins with yet unknown functions. Experiment Overall Design: Using GINI2 as a method of identifying novel biallelic truncating mutations in MSI+ colon cancer cells, various treatment conditions were applied to cultured colon cancer cell lines LS180 (MSI+) and SW480 (MSI-) and gene expression profiling was measured using Affymetrix GeneChip U133 Plus 2 arrays.
2008-06-13 | E-GEOD-5486 | biostudies-arrayexpress
Project description:Identification of human glucocorticoid response markers using integrated multi-omic analysis [Peripheral blood mononuclear cells]
| PRJNA625267 | ENA
Project description:Microsatellite instability (MSI), caused by defective mismatch repair, is observed in a subset of colorectal cancers (CRCs). We evaluated somatic mutations in microsatellite repeats of genes chosen based on reduced expression in MSI CRC and existence of a coding mononucleotide repeat. Expression profiling of 34 MSI colorectal cancers and 15 normal colonic mucosas was performed in 2002. Comparison of malignant and healthy tissue.
2011-03-01 | E-GEOD-24514 | biostudies-arrayexpress
Project description:Gastric cancer (GC) is the world's third leading cause of cancer mortality. In spite of significant therapeutic improvement, the clinical outcome for patients with advanced GC is poor; thus, the identification and validation of novel targets is extremely important from a clinical point of view. We generated a wide, multi-level platform of GC models, comprising 100 Patient-derived xenografts (PDXs), primary cell lines and organoids. Samples were classified according to their histology, microsatellite stability (MS) and Epstein-Barr virus status, and molecular profile. This PDX platform is the widest in an academic institution and it includes all the GC histologic and molecular types identified by TCGA. PDX histopathological features were consistent with those of patients’ primary tumors and were maintained throughout passages in mice. Factors modulating grafting rate were histology, TNM stage, copy number variation of tyrosine kinases/KRAS genes and MSI status. PDX and PDX-derived cells/organoids demonstrated potential usefulness to study targeted therapy response. Finally, PDX transcriptomic analysis identified a cancer cell intrinsic MSI signature, which was efficiently exported to gastric cancer, allowing the identification -among MSS patients- of a subset of MSI-like tumors with common molecular assets and significant better prognosis. We generated a wide gastric cancer PDX platform, whose exploitation will help identify and validate novel 'druggable' targets and define the best therapeutic strategies. Moreover, transcriptomic analysis of GC PDXs allowed the identification of a cancer cell intrinsic MSI signature, recognizing a subset of MSS patients with MSI transcriptional traits, endowed with better prognosis.
2019-10-15 | GSE128459 | GEO
Project description:Gastric cancers with mismatch repair (MMR) inactivation are characterised by microsatellite instability (MSI). In this study, the transcriptional profile of 38 gastric cancers with and without MSI was analysed. Unsupervised analysis showed that the immune and apoptotic gene networks efficiently discriminated these two cancer types. Hierarchical clustering analysis revealed numerous gene expression changes associated with the MSI phenotype. Amongst these, the p53-responsive genes maspin and 14-3-3 sigma were significantly more expressed in tumours with than without MSI. A tight immunosurveillance coupled with a functional p53 gene response is consistent with the better prognosis of MSI cancers. Frequent silencing of MLH1 and downregulation of MMR target genes, such as MRE11 and MBD4, characterised MSI tumours. The downregulation of SMUG1 was also a typical feature of these tumours. The DNA repair gene expression profile of gastric cancer with MSI is of relevance for therapy response.
2008-12-18 | GSE13911 | GEO
Project description:Gastric cancers with mismatch repair (MMR) inactivation are characterised by microsatellite instability (MSI). In this study, the transcriptional profile of 38 gastric cancers with and without MSI was analysed. Unsupervised analysis showed that the immune and apoptotic gene networks efficiently discriminated these two cancer types. Hierarchical clustering analysis revealed numerous gene expression changes associated with the MSI phenotype. Amongst these, the p53-responsive genes maspin and 14-3-3 sigma were significantly more expressed in tumours with than without MSI. A tight immunosurveillance coupled with a functional p53 gene response is consistent with the better prognosis of MSI cancers. Frequent silencing of MLH1 and downregulation of MMR target genes, such as MRE11 and MBD4, characterised MSI tumours. The downregulation of SMUG1 was also a typical feature of these tumours. The DNA repair gene expression profile of gastric cancer with MSI is of relevance for therapy response. Experiment Overall Design: Genes differentially expressed between MSI and MSS tumours were identified as follows: (i) gene probe sets were pre-selected for being flagged as ‘PRESENT’ in at least 10 tumour samples (21,324 probe sets); (ii) the probe set signal values on the pre-selected probe sets were used to run a t-test between the two types of tumour samples; (iii) the false discovery rate (FDR) method was applied to the t-test calculated p-values to correct for multiple testing and (iv) a false discovery rate <0.05 and a t-test p-value < 0.01 were chosen as threshold criteria to identify the genes differentially expressed in tumours with and without MSI
2009-01-03 | E-GEOD-13911 | biostudies-arrayexpress