Homo sapiens
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA268381 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Somatic L1 retrotransposition events have been shown to occur in epithelial cancers1-8. Here, we attempted to determine how early somatic L1 insertions occurred during the development of gastrointestinal (GI) cancers. Using L1-targeted resequencing (L1-seq), we studied different stages of four colorectal cancers arising from colonic polyps, seven pancreatic carcinomas, as well as seven gastric cancers. Surprisingly, we found somatic L1 insertions not only in all cancer types and metastases, but also in colonic adenomas, well-known cancer precursors. Some insertions were also present in low quantities in normal GI tissues, occasionally caught in the act of being clonally fixed in the adjacent tumors. Insertions in adenomas and cancers numbered in the hundreds and many were present in multiple tumor sections implying clonal distribution. Our results demonstrate that extensive somatic insertional mutagenesis occurs very early during the development of GI tumors, probably before dysplastic growth. Here we show Human SNP 6.0 Array experiments on DNAs from four colorectal cancer patients (1BV, 2BV, 3BV, and 4BV) with polyps and metastases. Here we characterize the samples for CNVs and compare the samples' CNV status to their respective somatic L1 retrotransposition profile.
2015-08-10 | E-GEOD-63601 | biostudies-arrayexpress
Project description:Somatic L1 retrotransposition events have been shown to occur in epithelial cancers1-8. Here, we attempted to determine how early somatic L1 insertions occurred during the development of gastrointestinal (GI) cancers. Using L1-targeted resequencing (L1-seq), we studied different stages of four colorectal cancers arising from colonic polyps, seven pancreatic carcinomas, as well as seven gastric cancers. Surprisingly, we found somatic L1 insertions not only in all cancer types and metastases, but also in colonic adenomas, well-known cancer precursors. Some insertions were also present in low quantities in normal GI tissues, occasionally caught in the act of being clonally fixed in the adjacent tumors. Insertions in adenomas and cancers numbered in the hundreds and many were present in multiple tumor sections implying clonal distribution. Our results demonstrate that extensive somatic insertional mutagenesis occurs very early during the development of GI tumors, probably before dysplastic growth. We assessed the impact of somatic L1 insertions on the expression of the corresponding protein-coding genes by comparing protein abundance in the polyp with the highest number of somatic L1 insertions with that of its paired normal colon using mass spectrometry analysis. Of the 10 validated somatic insertions that were in protein coding regions in the polyp, two proteins – KIAA1217 and WARS2 – were downregulated in the adenoma >90% and >70%, respectively.
2015-08-11 | PXD001626 | Pride
Project description:Somatic L1 retrotransposition events have been shown to occur in epithelial cancers1-8. Here, we attempted to determine how early somatic L1 insertions occurred during the development of gastrointestinal (GI) cancers. Using L1-targeted resequencing (L1-seq), we studied different stages of four colorectal cancers arising from colonic polyps, seven pancreatic carcinomas, as well as seven gastric cancers. Surprisingly, we found somatic L1 insertions not only in all cancer types and metastases, but also in colonic adenomas, well-known cancer precursors. Some insertions were also present in low quantities in normal GI tissues, occasionally caught in the act of being clonally fixed in the adjacent tumors. Insertions in adenomas and cancers numbered in the hundreds and many were present in multiple tumor sections implying clonal distribution. Our results demonstrate that extensive somatic insertional mutagenesis occurs very early during the development of GI tumors, probably before dysplastic growth.
2015-08-10 | GSE63601 | GEO
Project description:Somatic retrotranspositions of various mobile genetic elements take place in tumors, and L1 retroelements physiologically transpose in neural progenitor cells during neurogenesis. We sequenced whole genomes of the neural progenitor cell-derived subependymal giant cell astrocytomas that typically affect patients suffering from the neurodevelopmental disease Tuberous Sclerosis. Here we show an unprecedented increased L1 retrotransposition in these tumors, with tens of thousands new genomic insertions, that preferentially invade genes involved in neural activity, synaptic transmission and cancer. The prevalent insertions are short, nested in preexisting L1 repeats in the same orientation, trimmed in both the 5’ and 3’ ends, representing unorthodox retrotransposition”. Most somatic L1 inserts in the genomically stable astrocytomas are nested in preexisting L1 elements. This preferred nested integration may act as a “lightning rod” mechanism dampening the effects of massive retrotransposition. In contrast, the enhanced transposition found in genomically unstable breast tumors includes regions of high-density clustered insertion, transposminos. These clustered insertions are expected to be more detrimental, as many of them are non-nested and frequently invade genic and exonic sequences. Exaggerated L1 retrotransposition may be a common stochastic damaging pathway in neurological disorders and cancer.
2016-12-31 | GSE56871 | GEO
Project description:L1 retrotransposons are active elements in the genome, capable of mobilization in neuronal progenitor cells. Previously, we showed that chromatin remodeling during neuronal differentiation allows for a transient stimulation of L1 transcription. The activity of L1 retrotransposons during brain development can impact gene expression and neuronal function. Here we show that L1 neuronal retrotransposition in rodents is increased in the absence of MeCP2, a protein involved in global methylation and human neurodevelopmental diseases. Using neuronal progenitor cells derived from human induced pluripotent stem cells and human tissues, we revealed that Rett syndrome patients, with MeCP2 mutations, have increased susceptibility for L1 retrotransposition. Our data demonstrate that disease-related genetic mutations can influence the frequency of neuronal L1 retrotransposition, thereby increasing brain-specific genetic mosaicism. Genetic reprogramming of somatic cells to a pluripotent state (induced pluripotent stem cells, or iPSCs) by over-expression of specific genes has been accomplished for fibroblasts derived from controls and Rett syndrome patients. Different clones from each were compared to respective original fibroblasts and a human embryonic stem cell line. Gene expression profiles measured using human genome Affymetrix Gene Chip arrays were grouped by hierarchical clustering, and correlation coefficients were computed for all pair-wise comparisons.
2010-11-11 | E-GEOD-21037 | biostudies-arrayexpress
Project description:Somatic L1 Retrotransposition of Colorectal Tumors
| PRJNA173389 | ENA
Project description:Somatic L1 Retrotransposition of Colorectal Tumors
| PRJNA173390 | ENA
Project description:Widespread endogenous retrotransposition generates somatic genetic mosaicism during human development
| PRJEB9178 | ENA
Project description:Throughout an individual’s lifetime, genomic alterations accumulate in somatic cells. However, the mutational landscape induced by retrotransposition of long interspersed nuclear element-1 (L1), a widespread mobile element in the human genome, is poorly understood in normal cells. Here, we explored the whole-genome sequences of 406 normal colorectal clones, 12 MUTYH-associated adenomatous clones, and 19 matched colorectal cancer tissues. In addition, we analyzed promoter DNA methylation status of retrotransposition-competent L1 (in 139 clones) and read-through RNA expression profiles (in 116 clones) to investigate the epigenetic regulation of L1 activity.
| EGAD00001010183 | EGA
Project description:L1 retrotransposons are active elements in the genome, capable of mobilization in neuronal progenitor cells. Previously, we showed that chromatin remodeling during neuronal differentiation allows for a transient stimulation of L1 transcription. The activity of L1 retrotransposons during brain development can impact gene expression and neuronal function. Here we show that L1 neuronal retrotransposition in rodents is increased in the absence of MeCP2, a protein involved in global methylation and human neurodevelopmental diseases. Using neuronal progenitor cells derived from human induced pluripotent stem cells and human tissues, we revealed that Rett syndrome patients, with MeCP2 mutations, have increased susceptibility for L1 retrotransposition. Our data demonstrate that disease-related genetic mutations can influence the frequency of neuronal L1 retrotransposition, thereby increasing brain-specific genetic mosaicism.
2010-11-11 | GSE21037 | GEO