miR-497 suppresses epithelial-mesenchymal transition and metastasis in colorectal cancer cells by targeting fos-related antigen-1.
OBJECTIVE
MicroRNAs have key roles in tumor metastasis. The acquisition of metastatic capability by cancer cells is associated with epithelial-mesenchymal transition (EMT). Here, we describe the role and molecular mechanism of miR-497 in colorectal cancer (CRC) cell EMT, migration, and invasion.


METHODS
Quantitative real-time polymerase chain reaction and Western blot assays were performed to detect the expression levels of miR-497 and Fos-related antigen-1 (Fra-1) in the CRC cells. HCT116 and SW480 cells with miR-497 overexpression or Fra-1 low expression were constructed by lipofection. Target prediction and luciferase reporter assays were performed to investigate whether Fra-1 is one of the targets of miR-497. Western blot and Transwell assays were performed to detect the effects of miR-497 and Fra-1 on CRC cell EMT, migration and invasion.


RESULTS
We searched the miRanda, TargetScan, and PicTar databases and found that Fra-1, a key driver of CRC metastasis, is a potential target of miR-497. Quantitative real-time polymerase chain reaction and Western blot analysis verified downregulation of miR-497 and upregulation of Fra-1 in CRC cells. Western blot and Transwell assays showed that overexpression of miR-497 suppresses CRC cell EMT, migration, and invasion. Luciferase gene reporter assay revealed that Fra-1 is a downstream target of miR-497 as miR-497 bound directly to the 3' untranslated region of Fra-1 messenger RNA. An inverse correlation was also found between miR-497 and Fra-1 in HCT116 and SW480 cells. Furthermore, knockdown of Fra-1 recuperated the effects of miR-497 overexpression.


CONCLUSIONS
miR-497 suppresses CRC cell EMT, migration, and invasion partly by targeting Fra-1.
Department of General Surgery, First Affiliated Hospital of Henan University of Chinese Medicine.
Nan
N
Zhang
Department of Hepatobiliary Surgery, Henan Provincial People's Hospital, Zhengzhou.
Quan
Q
Shen
Department of Integrated Chinese and Western Medicine, Tianjin First Central Hospital, Tianjin, People's Republic of China.
Pingping
P
Zhang
Fos-related antigen-1; colorectal cancer; epithelial–mesenchymal transition; metastasis; miR-497