Oncogenic and anticancer roles of miRNAs in colorectal cancer: A review

Colorectal cancer (CRC) is one of the most dangerous cancers that occur in colon or rectum epithelial cells. Some studies disclose that CRC not only is the third most deadly cancer globally, but also, it is increasing every year. Genetic factors and environmental conditions are two main agents that participate in CRC progress. Besides, other factors, including chronic inflammation, diet, family history, and lifestyle have crucial effects on the progress of CRC. One of the most common genetic factors is microRNAs (miRNA). These molecules are a class of non-coding single-stranded RNAs with 21-23 nucleotides that play critical roles in modulating gene expression. Some studies have shown that miRNAs have contributed to the initiation and development of CRC. For example, miR-21 has played an oncogenic role in the onset of adenoma in colon tissue and miR-145 can suppress CRC by hindering cancer cell migration and invasive. However, comprehensive investigations are required to detect miRNAs in CRC for inhibition and decline of death-related CRC disease in screening programs. Moreover, the application of miRNA to target specific genes of cancer cells can help to prepare novel micro or nano formations such as micelles, carbon nanotubes, dendrimers, peptides nanocarriers, micelles, and mesoporous silica nanocarriers based on these molecules. Therefore, in this review, we have elucidated both the oncogenic and anticancer functions of important types of miRNA in CRC