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.
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.
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.
Project description:At least six histone H1 variants exist in mammalian somatic cells that bind to the linker DNA and stabilize the nucleosome particle contributing to higher order chromatin compaction. In addition, H1 seems to be involved in the active regulation of gene expression. It is not well known whether the different variants have specific roles, are distributed differentially along the genome, or regulate specific promoters. By taking advantage of specific antibodies to H1 variants and HA-tagged recombinant H1 variants expressed in a breast cancer-derived cell line, we have investigated the distribution of the different somatic H1 variants (H1.2 to H1.5, H1.0 and H1X) in particular promoters and genome-wide. Genome-wide analysis of H1.0, H1.2, H1.4, H1X and H3
Project description:At least six histone H1 variants exist in mammalian somatic cells that bind to the linker DNA and stabilize the nucleosome particle contributing to higher order chromatin compaction. In addition, H1 seems to be involved in the active regulation of gene expression. It is not well known whether the different variants have specific roles, are distributed differentially along the genome, or regulate specific promoters. By taking advantage of specific antibodies to H1 variants and HA-tagged recombinant H1 variants expressed in a breast cancer-derived cell line, we have investigated the distribution of the different somatic H1 variants (H1.2 to H1.5, H1.0 and H1X) in particular promoters and genome-wide.
Project description:At least six histone H1 variants exist in mammalian somatic cells that bind to the linker DNA and stabilize the nucleosome particle contributing to higher order chromatin compaction. In addition, H1 seems to be involved in the active regulation of gene expression. It is not well known whether the different variants have specific roles, are distributed differentially along the genome, or regulate specific promoters. By taking advantage of specific antibodies to H1 variants and HA-tagged recombinant H1 variants expressed in a breast cancer-derived cell line, we have investigated the distribution of the different somatic H1 variants (H1.2 to H1.5, H1.0 and H1X) in particular promoters and genome-wide. Analysis of H1 (H1.0, H1.2, H1.3, H1.4, H1.5 and H1X) and H3 abundance in promoter regions