miR-503 inhibits cell proliferation and induces apoptosis in colorectal cancer cells by targeting E2F3.

OBJECTIVE

Colorectal cancer (CRC) is one of the major healthcare problems worldwide. A lot of miRNAs are aberrantly expressed in CRC and involved in its development and progression. The purpose of this study was to investigate the expression and function of miR-503 in CRC.

METHODS

miR-503 expression was detected in CRC tissues and cell lines by Quantitative real-time PCR. Cell proliferation was assessed by MTT assay. Cell apoptosis and cell cycle distribution were measured by flow cytometry. Moreover, luciferase reporter assay and western blot were performed to determine the potential target of miR-503 in CRC cells.

RESULTS

miR-503 was significantly decreased in CRC tissues and cell lines in comparison with controls. Overexpression of miR-503 in CRC cells remarkably inhibited cell proliferation and induced apoptosis. Furthermore, E2F3 was identified as a direct target of miR-503 in CRC cells and down-regulation of E2F3 had a similar effect as miR-503 overexpression on CRC cells. In addition, the expression of E2F3 was negatively correlated with miR-503 level in CRC tissues.

CONCLUSIONS

miR-503 inhibits cell proliferation and induces apoptosis by directly targeting E2F3 in CRC cells, indicating its potential application in CRC diagnosis and therapy.