microRNA-497 inhibits invasion and metastasis of colorectal cancer cells by targeting vascular endothelial growth factor-A.

Objectives: microRNAs (miRNAs), are non-coding RNAs that regulate gene expression, and are involved in tumour development. The aim of this study was to investigate microRNA-497 (miR-497) expression and its role in development of colorectal cancer (CRC).

Materials And Methods: RT-PCR was performed to detect expression of miR-497 in CRC cell lines (HCT8, LOVO, Ls-174, HCT116 and HT29) and in clinical cancer specimens. To further understand its role, we restored expression of miR-497 in the HCT116 cell line by transfection with miR-497 mimics or inhibitors. Effects of miR-497 on cell proliferation, migration and invasion of targets were also determined both in vitro and in vivo.

Results: miR-497 expression decreased in 34 CRC tissues compared to non-tumour tissues and in tumour cell lines. Overexpression of miR-497 did not inhibit cancer cell growth but suppressed metastasis and invasion both in vitro and in vivo. Vascular endothelial growth factor-A (VEGF-A) was confirmed to be a target of miR-497. Furthermore, we found overexpression of miR-497 altered expression of key molecules of the VEGF-A/ERK/MMP-9 signalling pathway.

Conclusions: Thus our results provide evidence that miR-497 might function as a metastasis suppressor in CRC. Targeting miR-497 may provide a strategy for blocking its metastasis.