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Colorectal cancer (CRC) is one of the leading causes of cancer deaths in Western countries. A significant number of CRC patients undergoing curatively intended surgery subsequently develop recurrence and die from the disease. MicroRNAs (miRNAs) are aberrantly expressed in cancers and appear to have both diagnostic and prognostic significance. In this study, we identified novel miRNAs associated with recurrence of CRC, and their possible mechanism of action. TaqMan® Human MicroRNA Array Set v2.0 was used to profile the expression of 667 miRNAs in 14 normal colon mucosas and 46 microsatellite stable CRC tumors. Four miRNAs (miR-362-3p, miR-570, miR-148a* and miR-944) were expressed at a higher level in tumors from patients with no recurrence (p < 0.015), compared to tumors from patients with recurrence. A significant association with increased disease free survival was confirmed for miR-362-3p in a second independent cohort of 43 CRC patients, using single TaqMan® microRNA assays. In vitro functional analysis showed that over-expression of miR-362-3p in colon cancer cell lines reduced cell viability, and proliferation mainly due to cell cycle arrest. E2F1, USF2 and PTPN1 were identified as potential miR-362-3p targets by mRNA profiling of HCT116 cells over-expressing miR-362-3p. Subsequently, these genes were confirmed as direct targets by Luciferase reporter assays. Their knockdown in vitro phenocopied the effects of miR-362-3p over-expression. We conclude that miR-362-3p may be a novel prognostic marker in CRC, and hypothesize that the positive effects of augmented miR-362-3p expression may in part be mediated through the targets E2F1, USF2 and PTPN1 Colorectal cancer (CRC) is one of the leading causes of cancer deaths in Western countries. A significant number of CRC patients undergoing curatively intended surgery subsequently develop recurrence and die from the disease. MicroRNAs (miRNAs) are aberrantly expressed in cancers and appear to have both diagnostic and prognostic significance. In this study, we identified novel miRNAs associated with recurrence of CRC, and their possible mechanism of action. TaqMan® Human MicroRNA Array Set v2.0 was used to profile the expression of 667 miRNAs in 14 normal colon mucosas and 46 microsatellite stable CRC tumors. Four miRNAs (miR-362-3p, miR-570, miR-148 a* and miR-944) were expressed at a higher level in tumors from patients with no recurrence (p

In the present study, whole-genome methylation arrays were applied to identify novel genes with tumor specific DNA methylation of promoter CpG islands in pre-malignant and malignant colorectal lesions. Using a combination of Illumina HumanMethylation27 beadchips, Methylation-Sensitive High Resolution Melting (MS-HRM) analysis, and Exon arrays (Affymetrix) the DNA methylation pattern of ~14.000 genes and their transcript levels were investigated in six normal mucosas, six adenomas, and 30 MSI and MSS carcinomas. Sixty eight genes with tumor-specific hypermethylation were identified (p

Colorectal cancer (CRC) is one of the leading causes of cancer deaths. Twenty-five percent of the patients radically treated for a stage II CRC (no lymph node or distant metastasis) later develop recurrence and dies from the disease. MicroRNAs (miRNAs) are aberrantly expressed or mutated in human cancers, and function either as tumour suppressors or oncogenes. Additionally, they also appear to have both diagnostic and prognostic significance. The aim of the present study was to identify miRNAs associated with recurrence of stage II CRC, followed up by an investigation of how these potential biomarkers functionally influence tumour cell behaviour. TaqMan® Human MicroRNA Array Set v2.0 was use to profile the expression of more than 600 miRNAs in 46 stage II CRC tumours (23 without recurrence and 23 with recurrence). Four miRNAs; were identified as being associated with recurrence of the disease. Kaplan Meier analysis showed significant correlations between low expression of the four miRNAs and poor prognosis. Functional characterization of their impact on cell viability using MTT analysis demonstrated that they all inhibit the viability of HCT116 cells. One miRNAs also inhibited the viability of DLD1, LS174T and SW480 cells and was selected for further analysis. In order to get an understanding of the mechanism by which the miRNA affect cellular growth it was decided to elucidate its target network. Candidate mRNAs targets were identified using an integrative approach combining in silico target prediction and transcript profiling. Initially, miRNA over-expression in HCT116 cells was followed by transcriptional profiling of transfected cells using GeneChip Human Exon 1.0 ST Arrays. Three in silico predicted miRNA targets showing differential mRNA expression upon miRNA up-regulation were selected for detailed analysis. Luciferase miRNA target reporter assays confirmed all three mRNAs to be direct targets. Secondly, siRNA mediated knock-down of the potential targets resulted in growth suppression of HCT116 cells, mimicking the effect of the miRNA. In conclusion, miRNAs are associated with recurrence of stage II CRC and has the capacity to inhibit cellular growth in vitro through binding to specific targets.