Homo sapiens
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA387302 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:DNA-hypermethylated human gastric cancer circumvents apoptosis in the absence of TP53 mutation (RNA-Seq)
| PRJNA994964 | ENA
Project description:DNA-hypermethylated human gastric cancer circumvents apoptosis and premature senescence in the absence of TP53 mutation
| PRJNA994936 | ENA
Project description:Forkhead box (Fox) proteins constitute an evolutionarily conserved family of transcriptional regulators whose deregulations lead to tumorigenesis. However, their regulation and function in gastric cancer are unknown. Promoter hypermethylation occurs during Helicobacter pylori (H pylori)-induced gastritis, but whether the deregulated genes contribute to the multi-step gastric carcinogenesis remains unclear. FOXD3 was found to be hypermethylated in a mouse model of H pylori infection and possess tumor-suppressive functions in gastric cancer cell lines. In order to characterize the direct targets of FOXD3 that confer its actions, we performed ChIP-chip in N87 gastric cancer cell line which express low level of FOXD3 in the nuclei of a sub-population of cells. Promoter hypermethylation occurs during Helicobacter pylori (H pylori)-induced gastritis, but whether the deregulated genes contribute to the multi-step gastric carcinogenesis remains unclear. We used MethylCap-microarray to identify hypermethylated genes in a mouse model of H pylori infection. human Samples: Human gastric tumor cell line, N87 was grown in RPMI1640 supplemented with 10% fetal bovine serum. ChIP assays were performed using anti-FOXD3 antibody. The immunoprecipitated-FOXD3 and -IgG DNA were used to probe the Agilent human ChIP-chip arrays. mouse Samples: Two-condition experiment, H pylori-infected vs. control gastric tissues. 2 dye-swap replicates.
2012-12-28 | E-GEOD-39490 | biostudies-arrayexpress
Project description:DNA methylation is a key contributor to normal mammalian development, although, abnormal CpG islands methylation has been described to have a role in carcinogenesis. In gastric cancer, it is observed a global hypomethylation within the bulk genome and local hypermethylation at specific tumor suppressor genes. Conversely, the absence of DNA methylation may be an important step in stable transcriptional activation of oncogenes, contributing to tumor development. The screening of genes modulated by DNA methylation in gastric cancer may contribute to the identification of tumor suppressor genes and/or oncogenes modulated by DNA methylation never described in this neoplasia. In this experiment we aimed to identify differentially expressed genes by comparing 5-Aza-2’-deoxycytidine (5-AZAdC)-treated and non-treated gastric cancer cell lines. 5-AZAdC is a demethylation agent and has received FDA approval for the treatment of myelodysplastic syndromes. This drug has also showed capacity to treat solid tumors with low dose. The ACP02 and ACP03 gastric cancer cell lines used in this experiment were previously established by our research group from primary gastric adenocarcinomas classified as diffuse and intestinal types, respectively. Both cell lines present chromosome 8 trisomy, MYC amplification, and TP53 loss of copy. Moreover, ACP03 is able to start a tumorigenesis process in Cebus apellas.
2019-04-30 | E-MTAB-7880 | biostudies-arrayexpress
Project description:Background: Tp53 is the most commonly mutated gene in cancer. Canonical Tp53 DNA damage response pathways are well characterized and classically thought to underlie the tumor suppressive effect of Tp53. Challenging this dogma, mouse models have revealed that p53 driven apoptosis and cell cycle arrest are dispensable for tumor suppression. Here, we investigated the inverse context of a p53 mutation predicted to drive expression of canonical targets, but is detected in human cancer. Methods: We established a novel mouse model with a single base pair mutation (GAG>GAC, p53E221D) in the DNA-Binding domain that has wild-type function in screening assays, but is paradoxically found in human cancer in Li Fraumeni syndrome. Using mouse p53 E221D and the the analogous human p53E224D mutant, we evaluated expression, transcriptional activation, and tumor suppression in vitro and in vivo. Results: Expression of human p53E224D from cDNA translated to a fully functional p53 protein. However, p53 E221D/E221D RNA transcribed from the endogenous locus is mis-spliced resulting in nonsense mediated decay. Moreover, fibroblasts derived from p53 E221D/E221D mice do not express a detectable protein product. Mice homozygous for p53 E221D exhibited increased tumor penetrance and decreased life expectancy compared to p53 WT animals. Conclusions: Mouse p53 E221D and human p53 E224D mutations lead to splice variation and a biologically relevant p53 loss of function in vitro and in vivo.
2024-07-28 | GSE239745 | GEO
Project description:Mutations in ARID1A, encoding a subunit of the BAF chromatin remodeling complex, rank amongst the most common molecular aberrations in human cancer. However, oncogenic consequences of ARID1A mutation in human cells remain poorly defined due to lack of forward human genetic model systems. Here, CRISPR/Cas9 knockout of ARID1A in primary TP53-/- human gastric organoids induced morphologic dysplasia, tumorigenicity and mucinous differentiation but impaired Wnt/b-catenin signaling. Genetic Wnt pathway activation rescued mucinous differentiation, but not hyperproliferation, suggesting alternative essential pathways of ARID1A-mediated transformation. ARID1A loss induced transcriptional regulatory modules characteristic of MSI and EBV subtype human gastric cancer, including FOXM1 regulation of multiple mitotic regulatory genes and BIRC5/survivin. Convergently, high-throughput compound screening indicated selective vulnerability of ARID1A-deficient organoids to BIRC5/survivin inhibition, functionally implicating BIRC5/survivin as an essential mediator of proliferation following initial ARID1A loss. However, CRISPR inactivation of ARID1A in established gastric cancer cell lines did not elicit sensitivity to BIRC5/survivin inhibitors, suggesting that this pathway may be selectively required during the early establishment of tumorigenesis. Overall, we define distinct pathways downstream of oncogenic ARID1A mutation, with non-essential Wnt-inhibited mucinous differentiation in parallel with essential transcriptional FOXM1/BIRC5-stimulated proliferation, indicating the general utility of organoid-based forward genetic cancer analysis in human cells.
2021-01-05 | GSE164179 | GEO
Project description:Li-Fraumeni syndrome (LFS) is a hereditary cancer predisposition syndrome associated with a highly penetrant and diverse tumor spectrum characterized by germline mutations in the TP53 tumor suppressor gene. To better understand how TP53 mutations predispose individuals with LFS to cancer development, we characterized tp53 R217H and R242H zebrafish lines as the first zebrafish p53 hotspot mutants (human R248 and R273H). These mutants have lost several key wildtype p53 functions and recapitulate many LFS phenotypes. Specifically, we have shown that the R217H and R242H alleles result in partial-to-no activation of key p53 target genes, are resistant to apoptosis in a dominant negative manner and exhibit a defective G1 cell-cycle checkpoint in vivo. The loss of these wildtype p53 functions predisposed the fish to develop spontaneous tumors as early as 6 months of age. Tumor histology resembles human sarcomas, a predominant LFS tumor type. tp53 R242H mutants developed tumors earlier with a higher lifetime incidence than tp53 null or R217H mutants, suggesting it is a more aggressive mutation, while the R217H allele may be hypomorphic. Additionally, we observed mutation-specific differences both in the tumor type and sex bias across tp53 null, R217H, and R242H genotypes with associated diverse transcriptomic and DNA methylome profiles, impacting metabolism, cell signalling, and biological macromolecule synthesis and degradation. These tp53 zebrafish mutants demonstrate fidelity to their human counterparts and provide new insights into underlying tumorigenesis mechanisms and kinetics, which may inform more tailored tumor surveillance approaches and novel therapeutic targets in LFS.
2024-05-22 | GSE267760 | GEO
Project description:Li-Fraumeni syndrome (LFS) is a hereditary cancer predisposition syndrome associated with a highly penetrant and diverse tumor spectrum characterized by germline mutations in the TP53 tumor suppressor gene. To better understand how TP53 mutations predispose individuals with LFS to cancer development, we characterized tp53 R217H and R242H zebrafish lines as the first zebrafish p53 hotspot mutants (human R248 and R273H). These mutants have lost several key wildtype p53 functions and recapitulate many LFS phenotypes. Specifically, we have shown that the R217H and R242H alleles result in partial-to-no activation of key p53 target genes, are resistant to apoptosis in a dominant negative manner and exhibit a defective G1 cell-cycle checkpoint in vivo. The loss of these wildtype p53 functions predisposed the fish to develop spontaneous tumors as early as 6 months of age. Tumor histology resembles human sarcomas, a predominant LFS tumor type. tp53 R242H mutants developed tumors earlier with a higher lifetime incidence than tp53 null or R217H mutants, suggesting it is a more aggressive mutation, while the R217H allele may be hypomorphic. Additionally, we observed mutation-specific differences both in the tumor type and sex bias across tp53 null, R217H, and R242H genotypes with associated diverse transcriptomic and DNA methylome profiles, impacting metabolism, cell signalling, and biological macromolecule synthesis and degradation. These tp53 zebrafish mutants demonstrate fidelity to their human counterparts and provide new insights into underlying tumorigenesis mechanisms and kinetics, which may inform more tailored tumor surveillance approaches and novel therapeutic targets in LFS.
2024-05-29 | GSE268283 | GEO
Project description:Genome-wide DNA methylation profiling reveals a novel hypermethylated biomarker PRKCB in gastric cancer
| PRJNA1135692 | ENA
Project description:Gastric cancer, a leading cause of cancer related deaths, is a heterogeneous disease, with little consensus on molecular subclasses and their clinical relevance. We describe four molecular subtypes linked with distinct patterns of molecular alterations, disease progression and prognosis viz. a) Microsatellite Instable: hypermutated intestinal subtype tumors occurring in antrum, best overall prognosis, lower frequency of recurrence (22%), with liver metastasis in 23% of recurred cases b) Mesenchymal-like: diffuse tumors with worst prognosis, a tendency to occur at an earlier age and highest recurrence (63%) with peritoneal seeding in 64% of recurred cases, low frequency of molecular alterations c) TP53-inactive with TP53 loss, presence of focal amplifications and chromosomal instability d) TP53-active marked by EBV infection and PIK3CA mutations. The key molecular mechanisms and associated survival patterns are validated in multiple independent cohorts, to provide a consistent and unified framework for further preclinical and clinical research. ACRG Gastric cohort: microarray profiles from 300 gastric tumors from gastric cancer patients.
2015-04-17 | E-GEOD-62254 | biostudies-arrayexpress