Project description:We showed that a large number of genes were deregulated in colorectal adenomas in comparison with colorectal normal mucosae. 37 colorectal adenoma and 9 colorectal normal mucosa samples were analyzed. We generated a comparison between adenomas and normal mucosae.
Project description:Traditional serrated adenoma (TSA) remains the least understood of all the colorectal adenomas although these lesions have been associated with a significant cancer risk- twice that of the conventional adenoma (CAD) and of the sessile serrated adenoma (SSA/P). This study was performed to investigate the proteomic profiles of the different colorectal adenomas to better assess the pathogenesis of TSA. We performed a global quantitative expression profile of 44 colorectal adenomas (12 TSA, 15 CAD, 17 SSA/Ps) and 17 normal colonic mucosa, conserved as formalin-fixed paraffin-embedded samples, by the label-free quantification (LFQ) method. Unsupervised consensus hierarchical clustering applied to the whole proteomic profile of the 44 colorectal adenomas identified four subtypes. The C1 and C2 were well-individualized clusters composed of most of the CAD (14/15) and most of the SSA (13/17) respectively. This is consistent with the fact that CAD and SSA/Ps are homogeneous but distinct colorectal adenoma entities. In contrast, TSA were subdivided into C3 and C4 clusters that also contained CAD and SSA/Ps, consistent with the more heterogeneous entity of TSA at the morphological and molecular levels. The comparison of the proteome expression profile between the adenoma subtypes and normal colonic mucosa further confirmed the heterogeneous nature of TSA that merged either on CAD or SSA, while CAD and TSA formed homogeneous and distinct entities. Furthermore, we identified LEFTY1 a new potential marker for TSA that may be relevant for the TSA pathogenesis. LEFTY1 is an inhibitor of the Nodal/TGFb pathway that we found to be one of the most overexpressed proteins specifically in the TSA and confirmed by immunohistochemistry. Taken together, our study confirms that CAD and SSA form homogenous but distinct colorectal adenoma entities while TSA are an heterogeneous entity and may arise from either SSA or from normal mucosa that will evolve along the conventional adenoma pathway.
Project description:Genetic and epigenetic alterations are a fundamental aspect of colorectal cancer formation. There is considerable heterogeneity between colorectal cancers regarding the mutations and methylated genes they carry, and this heterogeneity may arise early in the polyp-cancer sequence. However, our understanding of the epigenetic alterations and gene mutations in colon adenomas and their relation to colorectal cancer is incomplete. Thus, we have assessed the methylome in normal colon mucosa, tubular adenomas, and colorectal adenocarcinomas and have determined the relationship of these findings between adenomas and cancer in the colon. Genome-wide alterations in DNA methylation were found in the normal colon mucosa adjacent to colorectal cancer, tubular adenomas, and colorectal cancer. Three subgroups of CRCs and two subgroups of adenomas were identified on the basis of their DNA methylation patterns. The adenomas separated into a high-frequency methylation class (Adenoma-H) and a low-frequency methylation class. The adenoma-H polyps have a methylated DNA signature similar to non-CIMP CRCs, whereas those of the Adenoma-L class have a similar methylation pattern to normal colon mucosa. The CpGs that account for these signatures are located in intragenic/intergenic regions, which suggests that these two groups of adenomas arise from different stem cell populations.
Project description:We evaluated the profile of lncRNA and mRNA expression in 6 colorectal adenoma (CRA), 6 colorectal adenoma (CRC) and 6 matched normal mucosa (NOR) using the Exiqon miRCURY lncRNA and mRNA array,7th generation. We found that global dysregulated lncRNA and mRNAs between colorectal lesions and normal mucosa. Our findings implicates that dysregulation of lncRNA and mRNAs may play important role in the carcinogenesis and present therapeutic targets for CRC.
Project description:Genetic and epigenetic alterations are a fundamental aspect of colorectal cancer formation. There is considerable heterogeneity between colorectal cancers regarding the mutations and methylated genes they carry, and this heterogeneity may arise early in the polyp-cancer sequence. However, our understanding of the epigenetic alterations and gene mutations in colon adenomas and their relation to colorectal cancer is incomplete. Thus, we have assessed the methylome in normal colon mucosa, tubular adenomas, and colorectal adenocarcinomas and have determined the relationship of these findings between adenomas and cancer in the colon. Genome-wide alterations in DNA methylation were found in the normal colon mucosa adjacent to colorectal cancer, tubular adenomas, and colorectal cancer. Three subgroups of CRCs and two subgroups of adenomas were identified on the basis of their DNA methylation patterns. The adenomas separated into a high-frequency methylation class (Adenoma-H) and a low-frequency methylation class. The adenoma-H polyps have a methylated DNA signature similar to non-CIMP CRCs, whereas those of the Adenoma-L class have a similar methylation pattern to normal colon mucosa. The CpGs that account for these signatures are located in intragenic/intergenic regions, which suggests that these two groups of adenomas arise from different stem cell populations. We conducted genome-wide array-based studies and comprehensive data analyses of aberrantly methylated loci in 41 normal colon samples, 42 colon adenomas, and 64 colorectal cancers. Supplementary file 'GSE48684_Matrix_signal_intensities_1.txt.gz': includes the unmethylated and methylated signal intensities from Samples GSM1183439-GSM1183561. Supplementary file 'GSE48684_Matrix_signal_intensities_2.txt.gz': includes the unmethylated and methylated signal intensities from Samples GSM1235135-GSM1235158.