Differential microRNA expression tracks neoplastic progression in inflammatory bowel disease-associated colorectal cancer

摘要

One of the most serious complications faced by inflammatory bowel disease (IBD) is the potential development of colorectal cancer (CRC). There is a compelling need to enhance the accuracy of cancer screening of IBD patients. MicroRNAs (miRNAs) are small non-protein-coding RNAs that play important roles in CRC oncogenesis. In this study, we report differential miRNA expression in IBD patients with associated CRC, from non-neoplastic tissue to dysplasia and eventually cancer. In addition, we identify and examine the role of dysregulated miRNAs in the TP53 pathway. In our CD patients, six miRNAs were up-regulated from non-neoplastic tissue to dysplasia, but down-regulated from dysplasia to cancer (miR-122, miR-181a, miR-146b-5p, let-7e, miR-17, miR-143) (p<0.001). Six differentially expressed miRNAs affected the TP53 pathway (miR-122, miR-214, miR-372, miR-15b, let-7e, miR-17) (p<0.001). Using two human colon cancer cell lines (HT-29 and HCT-116), E2F1, an upstream regulator of TP53, was down-regulated in both cell lines transfected with let-7e (p<0.05) as well as in HCT-116 cells transfected with miR-17 (p<0.05). Additionally, cyclin G, a cell-cycle regulator miR-122 target was down-regulated in both cell lines (p<0.05). Unique differentially expressed miRNAs were observed in CD-associated CRC progression. Six of these miRNAs had a tumorigenic effect on the TP53 pathway; the effect of three of which was studied using cell lines.