Expression and significance analyses of microRNAs in colorectal cancer

MicroRNAs (miRNAs or miRs) serve as potential diagnostic and prognostic markers or therapeutic targets. However, their roles in the pathogenesis of colorectal cancer (CRC) is not fully understood. The aim of the present study was to investigate the expression levels and functions of miR-205, miR-376c, and miR-539 in CRC development and prognosis. Multiple GEO databases were used to explore miRNA expression levels and associations in CRC cancer and adjacent/normal tissues. In addition, the associations between the expression of the miRNAs and the clinicopathological features of CRC were analyzed. The clinical data and specimens of 25 patients with CRC were collected, detected and analyzed. Combining bioinformatics analysis and databases, the relationship between the three miRNAs and CRC progression and prognosis was explored. In the GSE41655 dataset, miR-376c, miR-539, and miR-205 were all downregulated in tumor tissues, with miRNA-376c exhibiting the most pronounced downregulation. MiR-376c was closely associated with CRC liver metastasis, especially in the synchronous metastasis condition. Additionally, in the miRDB database, an analysis of the overlapping predicted target genes for miR-205, miR-376c, and miR-539 revealed that these three miRNAs share 53 common predicted target genes. Not only did miR-539 and miR-205 significantly differ according to tumor stage and lymph node metastasis, but also their upregulation was significant in tumor advanced stage and lymph node metastasis according to logistic regression in collected cancer tissues. Furthermore, miR-205 was significantly upregulated in tumor differentiation according to logistic regression. In conclusion, miR-205, miR-376c, and miR-539 were revealed to be involved in the development and prognosis of CRC and may be potential targets for CRC therapy.